JP2017041248A - Servo controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the position control accuracy and speed control accuracy of a servo control device because a speed estimate value is acquired by pseudo-differentiation of a position detection value related to a controlled object in a conventional servo control device. SOLUTION: In a servo control device, a speed estimator for estimating the speed of a controlled object is a Kalman filter based on dynamic characteristics from a control command value to a position detection value in a frequency domain including a speed control band of the servo control device. The position detection value of the control target and the control command value to the control target are input to calculate the speed estimation value of the control target and feed it back to the control system. [Selection diagram] Fig. 1

Description

  The present invention relates to a servo control apparatus including a position control system that controls the position of a control target and a speed control system that controls the speed of the control target.

  The configuration of the conventional most basic servo control device 200 is shown in FIG. The servo control device 200 detects a position by controlling a control object 1 having a position x defined by translational displacement or rotational displacement as a controlled variable, and sampling the position x at a predetermined sampling period, and further quantizing it at a predetermined detection resolution. A position detector 2 that outputs as a value 104, a speed estimator 210 (pseudo-differentiator) that outputs a speed estimation value 105 of the control object 1 based on a pseudo-differentiation of the position detection value 104, and a position command value given from the outside Based on 101 and the position detection value 104, the position controller 3 that calculates and outputs the speed command value 102, and on the basis of the speed command value 102 and the speed estimated value 105, calculates and outputs the control command value 103. And an actuator 5 that applies a control force or a control torque to the controlled object 1 based on the control command value 103. In the servo control device 200, the stability as the control system, the quick response to the change of the position command value 101, and the deviation between the position command value 101 and the position detection value 104 in the steady state satisfy the desired performance. A speed control system as a control system inner loop is designed by the speed controller 4, and a position control system as a control system outer loop is designed by the position controller 3.

  The meanings of the symbols shown in FIG. 10 are as follows.

  Another example of the conventional servo control device 200 is a position control device described in Patent Document 1. In this position control device, the control object 1, the position detector 2, the position controller 3, the speed controller 4, and the actuator 5 have the same configuration as the most basic servo control device 200 shown in FIG. On the other hand, in this position control device, a Kalman filter and a disturbance estimator are added to the feedback loop of the position detection value 104, and the position estimation value and speed estimation value of the controlled object 1 are estimated from the position detection value 104 in the Kalman filter. The disturbance estimator estimates a disturbance estimated value applied to the control object 1 from the control command value 103 and the speed estimated value. After that, the position estimated value is fed back to the position controller 3 and the speed estimated value is fed back to the speed controller 4, whereby the influence of observation noise superimposed on the position detection value 104, the influence of quantization noise, and When a pseudo-differentiator is applied as a speed estimator, the influence of differential noise superimposed on the speed estimated value is reduced. Furthermore, by making a signal obtained by subtracting the estimated disturbance value from the output of the speed controller 4 as the control command value 103 for the controlled object, the disturbance acting on the controlled object 1 is compensated, and the speed fluctuation and position fluctuation are suppressed. Yes.

JP 2000-148207 A

  Thus, in the most basic conventional servo control apparatus 200, a pseudo-differentiator is applied as the speed estimator 210, and the speed of the control target is determined based on the pseudo-differentiation of the position detection value 104 detected by the position detector 2. An estimated value 105 is acquired.

  However, in such a servo control device, due to the quantization by the position detector 2, even if the true position x is a constant value, the position detection value 104 uses the detection resolution of the position detector 2 as a minimum unit. Spike-like speed estimation errors occur due to the pseudo differentiation of the position detection value 104 that fluctuates in a rectangular wave shape and further changes in the speed estimated value 105 in a rectangular wave shape. Therefore, in the conventional servo control apparatus 200 to which a pseudo-differentiator is applied as the speed estimator 210, the position detection value 104 that fluctuates in a rectangular wave shape and the speed estimation value 105 on which the spike-like speed estimation error is superimposed are fed back. Since the position control and the speed control are performed, there is a problem that the position control accuracy and the speed control accuracy are deteriorated particularly in a low-speed drive region where the operation speed of the controlled object 1 is near zero.

  In such a servo control device 200, in order to improve the position control accuracy and the speed control accuracy in the low-speed drive region, it is necessary to improve the detection resolution in the position detector 2. However, since there is a limit to the realizable detection resolution, there is a problem that the position control accuracy and the speed control accuracy are limited by the detection resolution of the position detector 2.

  In addition, when the position detection value 104 includes a fluctuating position detection error synchronized with the true position x, the position detection error is also pseudo-differentiated in the speed estimator 210. There is also a problem that the speed control accuracy of the servo control device 200 deteriorates, particularly in the region where the operation speed of the control target 1 is medium-to-high speed driving, with the fluctuating speed estimation error amplified.

  In order to solve the above problem, the position control device described in Patent Document 1 estimates the position estimated value and the speed estimated value of the controlled object 1 from the position detected value 104 by the Kalman filter, thereby superimposing an error superimposed on the position detected value 104. The error component of the speed estimation value 105 to be superposed due to the component and the pseudo differentiation of the error component is reduced.

  However, even in such a position control device, since the Kalman filter estimates the position estimation value and the speed estimation value based only on the position detection value 104 of the control target 1, there is a limit to improving the estimation accuracy. That is, there is a problem that the position control accuracy and speed control accuracy that can be realized by the position control device are limited.

  In addition, when the error of the position detection value 104 with respect to the true position x expands for a certain period due to bit inversion generated in the position detector 2, the position estimation value and the speed estimation value estimated by the Kalman filter are used. However, there is also a problem that the position control accuracy and the speed control accuracy are inevitably deteriorated even if they are temporarily superimposed.

  The present invention has been made in order to solve the above-described problems. In the low-speed driving region, the influence of the rectangular wave-like fluctuation of the position detection value 104 and the influence of the spike-like speed estimation error superimposed on the speed estimation value 105 are achieved. And minimizing the effects of variable position detection error and speed estimation error superimposed on the position detection value 104 and the speed estimation value 105 in the medium / high speed drive region, and improving the position control accuracy and speed control accuracy in the entire drive region. The object is to realize an improved servo control device.

  Further, even when the error of the position detection value 104 with respect to the true position x increases for a certain period due to the defective operation of the position detector 2, the true position x and the true speed are estimated with high accuracy and the servo is detected. An object of the present invention is to realize a servo control device capable of suppressing deterioration in position control accuracy and speed control accuracy during the period by feeding back to the control device.

  In addition, when position control accuracy and speed control accuracy to be realized are given, a position detector having a lower resolution than the detection resolution conventionally required for the position detector 2 based on the control accuracy is provided. The object is to realize a servo control device that can satisfy the control accuracy even when applied.

The servo control device of the present invention is
A controlled object whose controlled variable is a position defined by translational displacement or rotational displacement;
A position detector that detects the position of the controlled object and outputs a position detection value;
A speed estimator that estimates a speed defined by a translation speed or a rotational speed of the control target based on at least the position detection value and outputs the speed as a speed estimation value;
A position controller that calculates and outputs a speed command value to be controlled based on a position command value given from the outside and the position detection value;
Based on the speed command value and the speed estimated value, a speed controller that calculates and outputs a control command value for a control target;
An actuator for applying a control force for controlling the translational displacement or a control torque for controlling the rotational displacement to the controlled object based on the control command value.
The speed estimator is configured with a Kalman filter based on dynamic characteristics from the control command value to the position detection value in a frequency region including the speed control band of the servo control device. The control command value is input, and the estimated speed value of the control target is estimated and output.

  Further, the speed estimator includes a stationary Kalman filter to which a stationary Kalman gain is applied after the Kalman filter converges to a constant coefficient filter, and the position detection value and the control command value are input to input the speed estimation of the control target. You may comprise so that a value may be estimated and output.

Further, the Kalman filter or the stationary Kalman filter constituting the speed estimator may be configured to estimate and output the position estimation value of the controlled object in addition to the speed estimation value.
In that case, the servo control device further includes:
A delay unit that generates and outputs a delay signal of the position estimation value;
A first position signal selector that selects one of the position estimation value and the position detection value based on a position selection signal and outputs the position feedback signal;
A second position signal selector for selecting one of the delay signal of the position estimation value output from the delay unit and the position detection value based on the position selection signal and outputting the selected signal as a speed estimator input signal; ,
A position selection signal controller that generates and outputs a position selection signal to be input to the first and second position signal selectors based on the speed estimator input signal and the position detection value.
The Kalman filter or the stationary Kalman filter constituting the speed estimator receives the speed estimator input signal and the control command value or the speed deviation between the speed command value and the speed estimated value as inputs. The position estimated value and the speed estimated value are estimated and output. The position controller calculates and outputs the speed command value based on the position command value given from the outside and the position feedback signal.

The servo control device of the present invention is
A controlled object whose controlled variable is a position defined by translational displacement or rotational displacement;
A position detector that detects the position of the controlled object and outputs a position detection value;
A speed estimator that estimates a speed and a position defined by a translation speed or a rotational speed of the control target based on at least the position detection value, and outputs the speed estimation value and the position estimation value;
A position controller that calculates and outputs a speed command value to be controlled based on a position command value given from the outside and the position detection value;
Based on the speed command value and the speed estimated value, a speed controller that calculates and outputs a control command value for a control target;
An actuator for applying a control force for controlling translational displacement or a control torque for controlling rotational displacement based on the control command value;
A first delay unit that generates and outputs a delay signal of the position estimation value;
A disturbance estimator that estimates a disturbance acting on the control target based on the position detection value and a delay signal of the position estimation value output from the first delay unit, and outputs the disturbance estimation value;
A second delay unit that generates and outputs a delay signal of the control command value.
The speed estimator includes a Kalman filter based on dynamic characteristics from the control command value to the position detection value in a frequency region including the speed control band of the servo control device, and the position detection value, The disturbance estimated value and the delay signal of the control command value output from the second delay device are input, and the speed estimated value and the position estimated value of the controlled object are estimated and output.

  Further, the speed estimator includes a stationary Kalman filter to which a stationary Kalman gain is applied after the Kalman filter converges to a constant coefficient filter, and is output from the position detection value, the disturbance estimated value, and the second delay unit. The control command value delay signal may be input and the speed estimation value and the position estimation value of the control target may be estimated and output.

The servo control device may be configured as follows.
The disturbance estimator is configured to determine whether to execute or stop the disturbance estimation operation based on the position selection signal.
The servo control device further comprises:
A first position signal selector that selects one of the position detection value and the position estimation value based on the position selection signal and outputs the position detection signal as a position feedback signal to the position controller;
A second position signal that selects either one of the position detection value and a delay signal of the position estimation value output from the first delay unit based on the position selection signal and outputs it as a speed estimator input signal A selector,
Input to the first position signal selector, the second position signal selector, and the disturbance estimator based on the position detection value and the delay signal of the position estimation value output from the first delay unit. And a position selection signal controller that generates and outputs the position selection signal.
A Kalman filter or a stationary Kalman filter constituting the speed estimator includes a control command value output from the speed estimator input signal from the second position signal selector, the disturbance estimated value, and the second delay unit, or Using the speed deviation delay signal as an input, the speed estimation value and the position estimation value of the control object are estimated and output.
The position controller calculates and outputs the speed command value based on the position command value given from the outside and the position feedback signal from the first position signal selector.

  According to the present invention, the speed estimator is configured with a Kalman filter, and the speed estimation value is estimated based on the position detection value and the control command value. In addition, it is possible to improve the position control accuracy and speed control accuracy of the servo control device in the entire drive region including medium and high speed.

  In addition, the speed estimator is configured with a steady Kalman filter, and the speed estimation value is estimated based on the position detection value and the control command value, so that the speed estimation accuracy for the true speed and the position control accuracy and speed control of the servo controller It is possible to greatly reduce the amount of calculation in the speed estimator while maintaining the accuracy at the same level as when the Kalman filter is applied.

  Furthermore, according to the present invention, since the speed estimation accuracy in the speed estimator is increased, a position control accuracy equivalent to the conventional level is achieved by a servo control device to which a position detector having a lower resolution than in the past is applied. In addition, speed control accuracy can be realized.

  In addition, according to the present invention, even when the error of the position detection value with respect to the true position is expanded for a certain period due to the defective operation of the position detector, the Kalman filter or the stationary Kalman filter constituting the speed estimator is Based on the delay signal of the position estimation value and the control command value or speed deviation, the true position and the true speed are estimated with high accuracy and fed back to the servo controller. Therefore, it is possible to suppress the deterioration of the position control accuracy and the speed control accuracy of the servo control device during the period.

  According to the present invention, the speed estimator is configured by a Kalman filter, and the speed estimation value is estimated based on the position detection value, the disturbance estimation value, and the delay signal of the control command value. Regardless, the accuracy of speed estimation with respect to the true speed can be increased. The position control accuracy and speed control accuracy of the servo control device can be improved in all drive regions including low speed and medium / high speed.

  In addition, the speed estimator is composed of a steady Kalman filter, and the speed estimation value is estimated based on the position detection value, disturbance estimation value, and delay signal of the control command value. It is possible to significantly reduce the amount of calculation in the speed estimator while maintaining the position control accuracy and speed control accuracy of the apparatus at the same level as when the Kalman filter is applied.

  Furthermore, according to the present invention, since the speed estimation accuracy in the speed estimator is increased, a position control accuracy equivalent to the conventional level is achieved by a servo control device to which a position detector having a lower resolution than in the past is applied. In addition, speed control accuracy can be realized.

  In addition, according to the present invention, even when the error of the position detection value with respect to the true position is expanded for a certain period due to the defective operation of the position detector, the Kalman filter or the stationary Kalman filter constituting the speed estimator is Based on the delay signal of the position estimation value, the disturbance estimation value, and the delay signal of the control command value or speed deviation, the true position and the true speed are estimated with high accuracy and fed back to the servo controller. Therefore, it is possible to suppress the deterioration of the position control accuracy and the speed control accuracy of the servo control device during the period.

1 is a block diagram showing a configuration of a servo control device 100 according to a first embodiment. In the conventional basic servo control apparatus 200, it is a time waveform figure which shows the time response characteristic simulation result when a position command value is made into a fixed value. FIG. 6 is a time waveform diagram showing a time response characteristic simulation result when the position command value is a constant value in the servo control device 100 according to the first embodiment. In the conventional basic servo control apparatus 200, it is a time waveform figure which shows the time response characteristic simulation result when the time change rate of a position command value is made into a predetermined fixed value. FIG. 7 is a time waveform diagram showing a time response characteristic simulation result when the time change rate of the position command value is set to a predetermined constant value in the servo control device 100 according to the first embodiment. FIG. 6 is a block diagram illustrating a configuration of a servo control device 100 according to a second embodiment. FIG. 6 is a block diagram showing a configuration of a servo control device 100 according to a third embodiment. In the servo control apparatus 100 by Embodiment 2, it is a time waveform figure which shows the time response characteristic simulation result when the error of a position detection value expands for a fixed period. FIG. 10 is a time waveform diagram showing a time response characteristic simulation result when the error of the position detection value is expanded for a certain period in the servo control apparatus 100 according to the third embodiment. It is a block diagram which shows the structure of the conventional basic servo control apparatus 200. FIG. It is a block diagram which shows the structure of the servo control apparatus 100 by Embodiment 4. In the conventional basic servo control apparatus 200, it is a time waveform figure which shows the time response characteristic simulation result when a position command value is made into a fixed value. In the servo control apparatus 100 by Embodiment 4, it is a time waveform figure which shows the time response characteristic simulation result when a position command value is made into a fixed value. In the conventional basic servo control apparatus 200, it is a time waveform figure which shows the time response characteristic simulation result when the time change rate of a position command value is made into a predetermined fixed value. FIG. 10 is a time waveform diagram showing a time response characteristic simulation result when the time change rate of the position command value is set to a predetermined constant value in the servo control device 100 according to the fourth embodiment. FIG. 10 is a block diagram showing a configuration of a servo control device 100 according to a fifth embodiment. It is a block diagram which shows the structure of the servo control apparatus 100 by Embodiment 6. In the servo control apparatus 100 according to the fifth embodiment, it is a time waveform diagram showing a time response characteristic simulation result when the error of the position detection value is expanded for a certain period. In the servo control device 100 according to the sixth embodiment, it is a time waveform diagram showing a time response characteristic simulation result when the error of the position detection value is expanded for a certain period.

Embodiment 1 FIG.
The first embodiment will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the servo control apparatus 100 according to the first embodiment. In FIG. 1, the same components as those in FIG. The meaning of the symbols shown in FIG. 1 is the same as the meaning of the symbols in FIG.

FIG. 2 shows a simulation result of a time response characteristic of a control command value, a true speed and a speed estimation value, a true position and a position detection value when the position command value is a constant value in the conventional basic servo control device 200. FIG.
FIG. 3 shows a time response characteristic simulation result of the control command value, the true speed and the estimated speed value, the true position and the position detection value when the position command value is a constant value in the servo control device 100 according to the first embodiment. FIG.

FIG. 4 shows a control command value, a true speed and a speed estimation value, a true position and a position detection value when the time change rate of the position command value is a predetermined constant value in the conventional basic servo control device 200. It is a time waveform figure which shows the time response characteristic simulation result.
FIG. 5 shows a control command value, a true speed and a speed estimation value, a true position and a position detection value when the time change rate of the position command value is a predetermined constant value in the servo control device 100 according to the first embodiment. It is a time waveform figure which shows the time response characteristic simulation result.

As shown in FIG. 1, in the servo control device 100 according to the first embodiment, the position x (translational displacement or rotational displacement), which is the control amount of the control target 1, is sampled at the sampling period in the position detector 2, and further The position detection value 104 is output after being quantized with a predetermined detection resolution.
The position controller 3 calculates and outputs the speed command value 102 of the servo controller 100 based on the deviation between the position command value 101 given from the outside and the position detection value 104 output from the position detector 2.
The speed controller 4 calculates the control command value of the servo controller 100 based on the deviation between the speed command value 102 output from the position controller 3 and the speed estimated value 105 output from the speed estimator 6a. Further, a signal obtained by subjecting the control command value to limit processing by the control command limiter 7 a is output as a final control command value 103.
The actuator 5 applies a control force or a control torque that causes the position x to follow the position command value 101 based on the control command value 103 output from the control command limiter 7a.
In the speed estimator 6a, based on the position detection value 104 output from the position detector 2 and the control command value 103 output from the control command limiter 7a, the speed defined by the translation speed or the rotation speed of the control target 1 Is output as a speed estimation value 105.

  At this time, a speed control system as a servo control system inner loop is designed by the speed controller 4, and a position control system as a servo control system outer loop is designed by the position controller 3. Thereby, the stability as the control system in the servo control device 100, the quick response of the position detection value 104 to the change of the position command value 101, and the deviation between the position command value 101 and the position detection value 104 in the steady state are desired. It can be adjusted to satisfy the performance.

  Next, the problems of the conventional basic servo control device 200 (FIG. 10) will be summarized, and the operation of the servo control device 100 according to the first embodiment will be described. In the conventional basic servo control device 200 shown in FIG. 10, for example, the speed estimator 210 is configured by an IIR filter obtained by bilinear transformation of a pseudo-differentiator whose continuous-system transfer function is given by the following pseudo-differentiator transfer function. doing. IIR is an abbreviation for Infinite Impulse Response.

At this time, even if the true position x is constant, due to quantization by the position detector 2, the position detection value 104 fluctuates in a rectangular wave shape with the detection resolution (1LSB) of the position detector 2 as the minimum unit. . LSB is an abbreviation for “Least Significant Bit”.
In the conventional basic servo control device 200, a spike-like speed estimation error occurs in the speed estimation value 105 estimated by the pseudo differentiation of the position detection value 104 that fluctuates in a rectangular waveform, and the position detection that fluctuates in a rectangular waveform. Position control and speed control are performed by feeding back the value 104 and the speed estimation value 105 on which the spike-like speed estimation error is superimposed.
Therefore, in the conventional basic servo control device 200, the position control accuracy and the speed control accuracy are deteriorated particularly in the low-speed drive region where the operation speed of the control target 1 is near zero.

As an example, in the conventional basic servo control device 200, the time of the control command value 103, the true speed and speed estimated value 105, the true position x, and the position detection value 104 when the position command value 101 is a constant value. The response simulation results are shown in FIG.
According to FIG. 2, the position detection value 104 fluctuates in a rectangular wave shape with the detection resolution (1LSB) as an amplitude, and a spike-like speed estimation error is superimposed on the speed estimation value 105, resulting in a control command value that should be essentially zero. It can be seen that the control accuracy of the true position x that should be zero and the true position x that should be a constant value is degraded.

In addition, when the position detection value 104 output from the position detector 2 includes a variable position detection error synchronized with the true position x, the position detection error is also pseudo-differentiated by the speed estimator 210. A variable speed estimation error obtained by amplifying the position detection error is superimposed on the value 105.
In the conventional basic servo control device 200, a position detection value 104 including a variable position detection error synchronized with the true position x and a speed estimation value including a variable speed estimation error synchronized with the true position x. 105 is fed back to perform position control and speed control.
In such a conventional basic servo control device, the speed control accuracy is deteriorated particularly in the region where the operation speed of the controlled object 1 is medium / high speed driving.

As an example, in the conventional basic servo control apparatus 200, the control command value 103, the true speed and the estimated speed value 105, the true position x and the position command value 101 when the time change rate of the position command value 101 is a predetermined constant value. The time response simulation result of the position detection value 104 is shown in FIG.
According to FIG. 4, as a result of superimposing a speed estimation error obtained by amplifying a variable position detection error synchronized with the true position x on the speed estimation value 105, the control command value 103 is also particularly synchronized with the speed estimation error. Thus, it can be seen that the control accuracy of the true speed, which should originally become a constant value, is deteriorated.
In FIG. 4, the true position x indicated by a solid line and the position detection value 104 indicated by a broken line overlap each other.

  Therefore, in the servo control device 100 (FIG. 1) according to the first embodiment, the dynamic characteristics from the control command value 103 to the position detection value 104, that is, the dynamic characteristics of the actuator 5, the control target 1, and the position detector 2 are servo servo. It is assumed that the rigid body characteristic can be approximated in the frequency region including the speed control band of the control device 100. The speed estimator 6a is configured by a Kalman filter given by the following Kalman gain, filter equation, and error covariance matrix equation.

As described above, in the servo control device 100 according to the first embodiment, the speed estimator 6a has the dynamic characteristics from the control command value 103 to the position detection value 104 in the frequency region including the speed control band of the servo control device 100 as rigid body characteristics. And a Kalman filter based on the sampling inertia _Td of the servo controller 100.
In the speed estimator 6a, the position detection value 104 output from the position detector 2 and the control command value 103 output from the control command limiter 7a are input as shown in FIG. The value 105 is estimated and fed back to the speed controller 4.

  By estimating the speed estimation value 105 by the speed estimator 6a, even if the position detection value 104 fluctuates in a rectangular wave shape with the detection resolution (1LSB) of the position detector 2 as the minimum unit, the speed estimation value 105 has a spike shape. Thus, the speed estimation accuracy for the true speed can be increased. Therefore, it is possible to improve the position control accuracy and the speed control accuracy of the servo control device 100 in the low-speed drive region where the operation speed of the control target 1 is near zero.

As an example, in the servo control device 100 according to the first embodiment, the time of the control command value 103, the true speed and the estimated speed value 105, the true position x, and the position detection value 104 when the position command value 101 is a constant value. The response simulation results are shown in FIG.
In the time response simulation related to FIG. 3 and the time response simulation related to FIG. 2 of the conventional basic servo control device 200, the vertical axis is the same scale, and the horizontal axis is the same scale. The basic configuration of the servo controller differs only in the speed estimator.
In FIG. 3, the true speed indicated by the solid line and the speed estimation value 105 indicated by the broken line overlap each other.

  According to FIG. 3, even if the position detection value 104 fluctuates in a rectangular wave shape with the detection resolution (1LSB) as an amplitude, the speed estimation value 105 output from the speed estimator 6a is as shown in FIG. There is no spike-like speed estimation error, and the true speed is estimated with high accuracy. As a result, the fluctuation amount of the control command value 103 is greatly suppressed as compared with FIG. 2, and the control accuracy of the true speed that should be essentially zero and the true position x that should be essentially a constant value is greatly improved. You can see that

  Even when the position detection value 104 output from the position detector 2 includes a variable position detection error synchronized with the true position x, the speed estimation value 105 has a variable position detection error amplified. A speed estimation error does not occur, and the speed estimation accuracy for the true speed can be increased. Therefore, it is possible to improve the speed control accuracy of the servo control device 100 in a region where the operation speed of the controlled object 1 is medium / high speed driving.

As an example, in the servo control apparatus 100 according to the first embodiment, the control command value 103, the true speed and the speed estimated value 105, the true position x, and the like when the time change rate of the position command value 101 is a predetermined constant value. The time response simulation result of the position detection value 104 is shown in FIG.
In the time response simulation related to FIG. 5 and the time response simulation related to FIG. 4 of the conventional basic servo control apparatus 200, the vertical axis is the same scale, and the horizontal axis is the same scale. The basic configuration of the servo controller differs only in the speed estimator.
In FIG. 5, the true speed indicated by a solid line and the speed estimation value 105 indicated by a broken line overlap each other.

  According to FIG. 5, the speed estimation value 105 does not have a fluctuating speed estimation error synchronized with the true position x found in the conventional basic servo control device 200 (FIG. 4). Is estimated with high accuracy. As a result, it can be seen that the fluctuation amount of the control command value 103 is significantly suppressed as compared with FIG. 4, and the control accuracy of the true speed that should be a constant value is greatly improved.

  As described above, according to the servo control device 100 according to the first embodiment, the speed estimator 6a can increase the speed estimation accuracy for the true speed, and the servo can be controlled in the entire drive region including the low speed and the medium speed. The position control accuracy and speed control accuracy of the control device 100 can be improved. In other words, it is possible to achieve position control accuracy and speed control accuracy of the same level as in the past by the servo control device 100 to which the position detector 2 having a lower resolution than in the past is applied.

  By the way, the first embodiment is merely an example. For example, it goes without saying that the control command limiter 7a shown in FIG.

  In this embodiment, the dynamic characteristics from the control command value to the position detection value, that is, the dynamic characteristics of the actuator, the controlled object, and the position detector are approximated by the rigid body characteristics in the frequency region including the speed control band of the servo control device. The velocity estimator was constructed with a Kalman filter, assuming that it was possible. In addition, the speed estimator estimates the speed estimation value of the control target by using the position detection value and the control command value as input, and feeds back to the speed controller.

  As a result, even if the position detection value fluctuates in a rectangular waveform with the detection resolution (1LSB) of the position detector as the minimum unit, the speed estimation value does not generate a spike-like speed estimation error, and the speed estimation for the true speed is performed. The accuracy can be increased. Therefore, it is possible to improve the position control accuracy and speed control accuracy of the servo control device in a low-speed drive region where the operation speed of the control target is near zero.

  In addition, even when the position detection value by the position detector includes a variable position detection error synchronized with the true position, the speed estimation value does not generate a variable speed estimation error in which the position detection error is amplified. The speed estimation accuracy for the true speed can be increased. Therefore, it is possible to improve the speed control accuracy of the servo control device in a region where the operation speed of the controlled object is medium and high speed driving.

  Therefore, it is possible to improve the position control accuracy and the speed control accuracy of the servo control device in the entire drive region including the low speed and the medium high speed. In other words, position control accuracy and speed control accuracy equivalent to the conventional level can be realized by a servo control device to which a position detector having a lower resolution than the conventional one is applied.

  In particular, in this embodiment, an equivalent inertia that approximates a dynamic characteristic from a control command value to a position detection value by a rigid body characteristic in a frequency region including a speed control band of the servo control apparatus, a sampling period of the servo control apparatus, The velocity estimator is configured by a Kalman filter constructed based on

  For this reason, a Kalman filter can be configured by the sampling period of the servo control device obtained as information with high accuracy and the equivalent inertia determined with high accuracy based on the measurement result of the actual machine characteristics. Thus, the accuracy of speed estimation with respect to the true speed can be further improved.

Embodiment 2. FIG.
The second embodiment will be described below with reference to the drawings.
FIG. 6 is a block diagram showing a configuration of the servo control apparatus 100 according to the second embodiment. In FIG. 6, the same components as those in FIG. The meanings of the symbols shown in FIG. 6 are as follows. However, the description of the same symbols as those in FIG. 1 is omitted.

As shown in FIG. 6, in the servo control device 100 according to the second embodiment, the speed deviation between the speed command value 102 output from the position controller 3 and the speed estimated value 105 output from the speed estimator 6b is calculated. Input to the speed deviation limiter 7b. Then, a speed deviation 106 obtained by performing a limit process on the speed deviation is input to the speed controller 4.
The speed controller 4 calculates and outputs the control command value 103 of the servo control device 100 based on the speed deviation 106 after the limit process output from the speed deviation limiter 7b.
The speed estimator 6b estimates the speed of the controlled object 1 on the basis of the position detection value 104 output from the position detector 2 and the speed deviation 106 output from the speed deviation limiter 7b. Output as.

Next, the operation of the servo control apparatus 100 according to the second embodiment will be described.
In the servo control device 100 (FIG. 6) according to the second embodiment, the dynamic characteristics from the speed deviation 106 to the position detection value 104, that is, the dynamic characteristics of the speed controller 4, the actuator 5, the control target 1, and the position detector 2 are obtained. It is assumed that the rigid body characteristic can be approximated in the frequency region including the speed control band of the servo control device 100. The speed estimator 6b is configured by a stationary Kalman filter given by the following filter equation.

In general, when the system parameters F _k , G _k , D _k , and H _k of the controlled object 1 are given as time-invariant systems F, G, D, and H that do not depend on time, the Kalman filter converges to a steady-state constant Kalman filter. . In particular, if (F, G) is stable and (H, F) is detectable, the stationary Kalman filter is asymptotically stable.
In the servo control device 100 according to the second embodiment, the steady Kalman gain after the Kalman filter converges to the constant coefficient filter is applied using the above characteristics. And the speed estimator 6b was comprised by the stationary Kalman filter.

In the servo control device 100 according to the second embodiment, the dynamic characteristics from the speed deviation 106 to the position detection value 104, that is, the dynamic characteristics of the speed controller 4, the actuator 5, the controlled object 1, and the position detector 2 are It is assumed that the rigid body characteristic can be approximated in the frequency region including the speed control band of the control device 100. The speed estimator 6b is configured by a stationary Kalman filter based on the sampling period _Td of the servo control device 100 and the speed control system gain intersection frequency ω _rc (the third equation of the filter equation (prediction)). ).
In this speed estimator 6b, the position estimation value 104 output from the position detector 2 and the speed deviation 106 output from the speed deviation limiter 7b are input as shown in FIG. The value 105 is estimated and fed back to the speed deviation limiter 7b.

By estimating the speed estimation value 105 by the speed estimator 6b having the above-described configuration, the dynamic characteristics from the control command value 103 to the position detection value 104, that is, the dynamic characteristics of the actuator 5, the control target 1, and the position detector 2 are obtained. Even when the equivalent inertia A approximated by the rigid body characteristic changes, if the constant low frequency region control characteristic (speed control system gain intersection frequency ω _rc ) can always be realized by the speed controller 4, the following becomes possible. That is, the position detection value 104 output from the position detector 2 and the speed controller 4 are input as the speed controller 4, the actuator 5, the control object 1, and the position detector 2 as a system that is estimated by the stationary Kalman filter. By using the speed deviation 106 as an input to the stationary Kalman filter, it is possible to maintain the estimation accuracy of the speed estimation value 105 with respect to the true speed at an arbitrary equivalent inertia A. In addition, the stationary Kalman filter in this case can be constructed based on the sampling period T _d of the servo control device 100 and the speed control system gain intersection frequency ω _rc .

  In this case, the consistency of the control command value 103 is obtained by applying the value obtained by equivalently converting the control command limit value in the control command limiter 7a shown in FIG. 1 by the following equation as the speed deviation limit value in the speed deviation limiter 7b. It is necessary to ensure.

Note that the second embodiment is merely an example. For example, it goes without saying that the speed deviation limiter 7b shown in FIG. 6 is not necessarily implemented. In the second embodiment, the steady Kalman filter constituting the speed estimator 6b is constructed based on the sampling period _Td of the servo controller 100 and the speed control system gain intersection frequency _ωrc . However, the stationary Kalman filter constituting the speed estimator 6b is equivalent to an equivalent inertia A in which the dynamic characteristic from the control command value 103 to the position detection value 104 is approximated by a rigid body characteristic in a frequency region including the speed control band of the servo controller 100. sampling period T _d of the servo control device _100, and be built on the basis of a proportional control gain K _D of the speed controller 4 may (second formula of the filter equation (predicted)).

  In this embodiment, the dynamic characteristics from the speed deviation to the position detection value, that is, the dynamic characteristics of the speed controller, the actuator, the control target, and the position detector are in the frequency domain including the speed control band of the servo controller. It is assumed that it can be approximated by rigid body characteristics. Then, the velocity estimator was configured with a stationary Kalman filter to which the stationary Kalman gain after the Kalman filter converged to the constant coefficient filter was applied. After that, the speed estimator estimates the speed estimation value of the control target using the position detection value and the speed deviation as inputs, and feeds back to the speed deviation limiter.

  This significantly reduces the amount of computation in the speed estimator while maintaining the estimated accuracy of the speed estimate for the true speed, that is, the position control accuracy and speed control accuracy of the servo controller, at the same level as when applying the Kalman filter. It becomes possible to make it.

  In addition, in this embodiment, on the premise that a constant low frequency region control characteristic (speed control system gain intersection frequency) can always be realized by the speed controller of the servo control device, the speed controller, the actuator, the controlled object, and A stationary Kalman filter was constructed using the position detector as the target system. The speed estimator configured by the stationary Kalman filter is configured to estimate and output a speed estimation value based on the position detection value and the speed deviation.

  As a result, even if the equivalent inertia, which approximates the dynamic characteristics from the control command value to the position detection value, that is, the dynamic characteristics of the actuator, the controlled object, and the position detector, is changed by the rigid body characteristics, any equivalent inertia can be obtained. It is possible to maintain the control accuracy of the speed estimation value with respect to the true speed.

  In particular, in this embodiment, the speed estimator is configured by a stationary Kalman filter constructed based on the sampling period of the servo control device and the speed control system gain intersection frequency.

  Therefore, the steady Kalman filter is based on the sampling period of the servo controller that has been conventionally obtained as highly accurate information and the speed control system gain intersection frequency that is measured with high accuracy based on the actual machine characteristics after the speed controller is designed. Can be configured. In the speed estimator, the speed estimation accuracy for the true speed can be further increased.

Embodiment 3 FIG.
The third embodiment will be described below with reference to the drawings.
FIG. 7 is a block diagram showing a configuration of the servo control apparatus 100 according to the third embodiment. In FIG. 7, the same components as those in FIG. The meanings of the symbols shown in FIG. 7 are as follows. However, the description of the same symbols as those in FIG. 6 is omitted.

FIG. 8 shows time response characteristics of the control command value, the true speed and the estimated speed value, and the true position and the position detection value when the error of the position detection value is expanded for a certain period in the servo control device 100 according to the second embodiment. It is a time waveform figure which shows a simulation result.
FIG. 9 shows the time response characteristics of the control command value, the true speed and the estimated speed value, the true position and the position detection value when the error of the position detection value is expanded for a certain period in the servo control device 100 according to the third embodiment. It is a time waveform figure which shows a simulation result.

As shown in FIG. 7, in the servo control device 100 according to the third embodiment, the speed estimator 6 b estimates and outputs the position estimated value 107 in addition to the speed estimated value 105 of the controlled object 1.
The delay unit 8 receives the position estimation value 107 output from the speed estimator 6b as input, and generates and outputs a 1-sampling delay signal 108.
In the first position signal selector 9, either the position estimation value 107 output from the speed estimator 6 b or the position detection value 104 output from the position detector 2 is received from the position selection signal controller 11. Selection is made based on the output position selection signal, and the position feedback signal is output.
In the second position signal selector 10, either the one sampling delay signal 108 of the position estimation value output from the delay unit 8 or the position detection value 104 output from the position detector 2 is used as the position selection signal. It selects based on the position selection signal output from the controller 11, and outputs it as a speed estimator input signal.
The position selection signal controller 11 selects the first position signal based on the speed estimator input signal output from the second position signal selector 10 and the position detection value 104 output from the position detector 2. A position selection signal to be input to the device 9 and the second position signal selector 10 is generated and output.
The speed estimator 6b estimates the position and speed of the control target 1 based on the speed estimator input signal output from the second position signal selector 10 and the speed deviation 106 output from the speed deviation limiter 7b. To do. Then, the speed estimator 6 b outputs the estimated position as the position estimated value 107 and outputs the estimated speed as the speed estimated value 105.
The position controller 3 calculates the speed command value 102 of the servo controller 100 based on the deviation between the position command value 101 given from the outside and the position feedback signal output from the first position signal selector 9. Output.

Next, in the servo control device 100 according to the second embodiment, the operation when the error of the position detection value 104 increases for a certain period will be described, and the operation of the servo control device 100 according to the third embodiment will be described.
In the servo control device 100 according to the second embodiment shown in FIG. 6, when the error of the position detection value 104 with respect to the true position x is expanded for a certain period due to the defective operation of the position detector 2, it is configured with a steady Kalman filter. The speed estimator 6b estimates the speed estimated value 105 based on the position detection value 104 on which an excessive error is superimposed. Therefore, the speed estimation accuracy for the true speed is degraded. At this time, the servo control device 100 performs position control and speed control by feeding back the position detection value 104 on which an excessive error is superimposed and the speed estimation value 105 with a deteriorated estimation accuracy, for a certain period. For this reason, the position control accuracy and the speed control accuracy are extremely deteriorated in accordance with the error amount superimposed on the position detection value 104 for a certain period.

As an example, in the servo control device 100 according to the second embodiment, the error of the position detection value 104 is approximately 50 ms from the time 0.1 s with the time change rate of the position command value 101 set to a predetermined constant value. FIG. 8 shows time response simulation results of the control command value 103, the true speed and the estimated speed value 105, the true position x, and the position detection value 104 when enlarged.
According to FIG. 8, the control command value 103 has reached the control command limit value corresponding to the speed deviation limiter 7b. That is, the estimation accuracy of the speed estimation value 105 is extremely deteriorated in accordance with an excessive error superimposed on the position detection value 104, and the control command value 103 is greatly disturbed. Therefore, it can be seen that a period of approximately 0.3 s is required until the servo control device 100 returns to the normal operation with respect to the error expansion period (50 ms) in the position detection value 104.

  Therefore, in the servo control device 100 (FIG. 7) according to the third embodiment, the stationary Kalman filter constituting the speed estimator 6b estimates the position estimated value 107 in addition to the speed estimated value 105 (the embodiment). The filter equation (estimation) described in 2 is used. That is, the position estimation value 107 is applied to the input signal to the speed estimator 6 b and the position feedback signal to the position controller 3 during the error expansion period of the position detection value 104. Thereby, deterioration of the position control accuracy and the speed control accuracy of the servo control device 100 due to the defective operation of the position detector 2 is suppressed.

Specifically, from the speed estimator 6b configured by a stationary Kalman filter, based on the filter equation (estimation) described in the second embodiment, in addition to the speed estimated value 105 of the control target 1, the position estimated value 107 Is also output. The position estimation value 107 is converted into a 1 sampling delay signal 108 corresponding to the sampling period of the servo control device 100 in the delay unit 8 and input to the first position signal selector 9.
In the first position signal selector 9, either the position estimation value 107 output from the speed estimator 6 b or the position detection value 104 output from the position detector 2 is received from the position selection signal controller 11. Selection is made based on the output position selection signal, and the position feedback signal is output.
In the second position signal selector 10, either the one sampling delay signal 108 of the position estimation value output from the delay unit 8 or the position detection value 104 output from the position detector 2 is used as the position selection signal. It selects based on the position selection signal output from the controller 11, and outputs it as a speed estimator input signal.

  The position selection signal controller 11 selects the first position signal based on the speed estimator input signal output from the second position signal selector 10 and the position detection value 104 output from the position detector 2. The position selection signal to be input to the device 9 and the second position signal selector 10 is switched and held based on the following conditions.

The speed estimator 6b estimates the position and speed of the control target 1 based on the speed estimator input signal output from the second position signal selector 10 and the speed deviation 106 output from the speed deviation limiter 7b. To do. Then, the speed estimator 6 b outputs the estimated position as the position estimated value 107 and outputs the estimated speed as the speed estimated value 105.
The position controller 3 calculates the speed command value 102 of the servo controller 100 based on the deviation between the position command value 101 given from the outside and the position feedback signal output from the first position signal selector 9. Output.

  Thereby, when the position detection value 104 output from the position detector 2 is normal, the position feedback signal (first output) fed back to the position controller 3 based on the condition (2) or the condition (3). The position detection value 104 is applied as usual as the position signal selector 9 output) and the speed estimator input signal (second position signal selector 10 output) input to the speed estimator 6b.

  On the other hand, when the error of the position detection value 104 is expanded for a certain period due to the defective operation of the position detector 2, a position feedback signal (first output) fed back to the position controller 3 based on the above condition (1). By applying the position estimation value 107 output from the speed estimator 6b to the position signal selector 9 output), the speed estimator input signal (second position signal selector 10 output) input to the speed estimator 6b. The one-sample delayed signal 108 of the position estimation value is applied. Thereby, deterioration of the position control accuracy and the speed control accuracy of the servo control device 100 due to the defective operation of the position detector 2 is suppressed.

As an example, in the servo control device 100 according to the third embodiment, the error of the position detection value 104 increases in a period of about 50 ms from the time 0.1 s with the time change rate of the position command value 101 set to a predetermined constant value. FIG. 9 shows the time response simulation results of the control command value 103, the true speed and the estimated speed value 105, the true position x, and the position detection value 104 in the case of the above.
In the time response simulation related to FIG. 9 and the time response simulation related to FIG. 8, the vertical axis is the same scale, and the horizontal axis is the same scale. Further, the error amount superimposed on the position detection value 104 is also the same.
In FIG. 9, the true speed indicated by the solid line and the speed estimated value 105 indicated by the broken line overlap each other.

According to FIG. 9, even if the error of the position detection value 104 is increased for a certain period due to the defective operation of the position detector 2, the speed estimation value 105 output from the speed estimator 6b is shown in FIG. The speed estimation accuracy is not deteriorated as described above, and the true speed is estimated with high accuracy.
During the error expansion period of the position detection value 104, the position estimated value 107 and the speed estimated value 105 whose speed estimation accuracy is greatly improved are fed back to the position controller 3 and the speed deviation limiter 7b, whereby the control command value 103 It can be seen that the fluctuation amount of the servo control device 100 is greatly suppressed as compared with FIG. 8, and the behavior of the servo control device 100 is maintained in a substantially normal operation.

  The third embodiment is merely an example. For example, it goes without saying that the speed deviation limiter 7b shown in FIG. In the third embodiment, the configuration of the delay unit 8 is set to one sampling delay corresponding to the sampling period of the servo control device 100. However, the configuration of the delay unit 8 is not necessarily set to one sampling delay. That is, the delay unit 8 may be constructed with an arbitrary delay amount. In addition, in the third embodiment, the speed estimator 6b is configured by a stationary Kalman filter. However, the speed estimator 6b may be configured by the Kalman filter described in the first embodiment. Further, the input of the speed estimator 6b may be constituted by a control command value and a speed estimator input signal.

  In the third embodiment, it is used that the stationary Kalman filter constituting the speed estimator estimates the position estimated value in addition to the speed estimated value. Then, in the error detection period of the position detection value, the position estimated value estimated by the stationary Kalman filter is applied to the position feedback signal to the position controller, and the position estimated value is sampled by one sampling delay to the input signal to the speed estimator. By applying the signal, the deterioration of the position control accuracy and the speed control accuracy of the servo control device due to the defective operation of the position detector is suppressed.

  As a result, even when the error of the position detection value with respect to the true position is expanded for a certain period due to the defective operation of the position detector, the stationary Kalman filter constituting the speed estimator performs the 1 sampling delay signal of the position estimation value. The true position and true speed are estimated with high accuracy based on the velocity deviation and the feedback to the servo controller. Therefore, it is possible to suppress the deterioration of the position control accuracy and the speed control accuracy of the servo control device during the period.

  In the third embodiment, when the absolute value of the error between the speed estimator input signal and the position detection value is greater than or equal to the first threshold by the position selection signal controller, the position feedback signal (first position signal selector) The position estimation value output from the speed estimator is applied to the output), and the speed estimator input signal (second position signal selector output) input to the speed estimator is delayed by one sampling delay of the position estimation value. Signal applied. Further, when the absolute error value between the speed estimator input signal and the position detection value converges below the second threshold, or when a preset return time has elapsed, the position feedback signal (first position signal selection) Device position output) and a speed estimator input signal (second position signal selector output) are both applied with conventional position detection values.

  As a result, regarding the switching of the output signals in the first and second position signal selectors, the output signals are switched both in the output signal switching by the error detection of the position detection value and in the output signal switching by the normal operation return of the position detector. The discontinuous change of the signal can be minimized. Therefore, it is possible to minimize the deterioration of the position control accuracy and the speed control accuracy of the servo control device due to the defective operation of the position detector. In addition, in the output signal switching by the normal operation return of the position detector, the output signal switching in the first and second position signal selectors is performed even when the preset return time has elapsed. The operation can be surely executed.

Embodiment 4 FIG.
Hereinafter, the fourth embodiment will be described with reference to the drawings.
FIG. 11 is a block diagram showing the configuration of the servo control apparatus according to the fourth embodiment. In FIG. 11, the same components as those in FIG. The meanings of the symbols shown in FIG. 11 are as follows. However, the description of the same symbols as those in FIG. 10 is omitted. Note that a lower right subscript k of a variable (symbol) represents a time kT _d (k = 0, 1, 2,...) Corresponding to the variable.

FIG. 12 shows a simulation result of time response characteristics of a control command value, a true speed and a speed estimation value, a true position and a position detection value when the position command value is a constant value in the conventional basic servo control device 200. FIG.
FIG. 13 shows a time response characteristic simulation result of a control command value, a true speed and a speed estimation value, a true position and a position detection value when the position command value is a constant value in the servo control device 100 according to the fourth embodiment. FIG.

FIG. 14 shows a control command value, a true speed and a speed estimation value, a true position and a position detection value when the time change rate of the position command value is a predetermined constant value in the conventional basic servo control device 200. It is a time waveform figure which shows the time response characteristic simulation result.
FIG. 15 shows a control command value, a true speed and a speed estimated value, a true position and a position detection value when the time change rate of the position command value is a predetermined constant value in the servo control device 100 according to the fourth embodiment. It is a time waveform figure which shows the time response characteristic simulation result.

As shown in FIG. 11, in the servo control apparatus 100 according to the fourth embodiment, the position x, which is the control amount of the controlled object 1, is sampled at the sampling period _Td in the position detector 2, and further, a predetermined detection resolution is obtained. in is quantized and output as the position detection value 104 at time kT _d. The position x is defined by translational displacement or rotational displacement.
The position controller 3 calculates and outputs the speed command value 102 for the control object 1 based on the deviation between the position command value 101 given from the outside and the position detection value 104 output from the position detector 2. .
The speed controller 4 calculates a control command value for the controlled object 1 based on the deviation between the speed command value 102 output from the position controller 3 and the speed estimated value 105 output from the speed estimator 6a. Further, a signal obtained by subjecting the control command value to limit processing by the control command limiter 7 a is output as a final control command value 103.
The actuator 5 applies a control force or a control torque that causes the position x to follow the position command value 101 based on the control command value 103 output from the control command limiter 7a.
The first delay unit 8a receives the position estimated value 107 output from the speed estimator 6a as an input, and generates and outputs a one-sample delay signal 108a corresponding to the sampling period _Td .
The disturbance estimator 12a acts on the controlled object 1 based on a position estimation error obtained by subtracting the one-sample delay signal 108a that is the output of the first delay unit 8a from the position detection value 104 output from the position detector 2. The disturbance is estimated and output as a disturbance estimated value 109a.
The second delay unit 8b receives the control command value 103 output from the control command limiter 7a as input, and generates and outputs a one-sample delay signal 108b corresponding to the sampling period _Td .
The speed estimator 6a receives the position detection value 104 output from the position detector 2, the disturbance estimation value 109a output from the disturbance estimator 12a, and the one-sample delay signal 108b output from the second delay unit 8b. As a result, the speed defined by the translation speed or the rotation speed of the control object 1 is estimated and output as a speed estimated value 105. Further, the speed estimator 6 a estimates the position x of the control target 1 and outputs it as a position estimated value 107.

  At this time, a speed control system as a servo control system inner loop is designed by the speed controller 4, and a position control system as a servo control system outer loop is designed by the position controller 3. Thereby, the stability as the control system in the servo control device 100, the quick response of the position detection value 104 to the change of the position command value 101, and the deviation between the position command value 101 and the position detection value 104 in the steady state are desired. It can be adjusted to satisfy the performance.

  Next, the problems of the conventional basic servo control device 200 (FIG. 10) will be summarized, and the operation of the servo control device 100 according to the fourth embodiment will be described. In the conventional basic servo control device 200 shown in FIG. 10, for example, the speed estimator 210 is changed by an IIR filter obtained by bilinear transformation of a pseudo-differentiator whose continuous transfer function is given by the following pseudo-differentiator transfer function. It is composed.

At this time, even if the true position x is constant, due to quantization by the position detector 2, the position detection value 104 fluctuates in a rectangular wave shape with the detection resolution (1LSB) of the position detector 2 as the minimum unit. .
In the conventional basic servo control device 200, a spike-like speed estimation error occurs in the speed estimation value 105 estimated by the pseudo differentiation of the position detection value 104 that fluctuates in a rectangular waveform, and the position detection that fluctuates in a rectangular waveform. The position control and the speed control are performed by feeding back the value 104 and the speed estimation value 105 on which the spike-like speed estimation error is superimposed.
Therefore, in the conventional basic servo control device 200, the position control accuracy and the speed control accuracy are deteriorated particularly in the low-speed drive region where the operation speed of the control target 1 is near zero.

As an example, in the conventional basic servo control device 200, the time of the control command value 103, the true speed and speed estimated value 105, the true position x, and the position detection value 104 when the position command value 101 is a constant value. The response simulation result is shown in FIG.
According to FIG. 12, the position detection value 104 fluctuates in a rectangular wave shape with the detection resolution (1LSB) as an amplitude, and a control command value 103 that should be essentially zero as a result of superimposing a spike-like speed estimation error on the speed estimation value 105. It can be seen that the control accuracy of the true speed that should be zero and the true position x that should be a constant value is degraded.

In addition, when the position detection value 104 output from the position detector 2 includes a variable position detection error synchronized with the true position x, the position detection error is also pseudo-differentiated by the speed estimator 210. A variable speed estimation error obtained by amplifying the position detection error is superimposed on the value 105.
In the conventional basic servo control device 200, a position detection value 104 including a variable position detection error synchronized with the true position x and a speed estimation value including a variable speed estimation error synchronized with the true position x. 105 is fed back to perform position control and speed control.
In such a conventional basic servo control device, the speed control accuracy is deteriorated particularly in the region where the operation speed of the controlled object 1 is medium / high speed driving.

As an example, in the conventional basic servo control apparatus 200, the control command value 103, the true speed and the estimated speed value 105, the true position x and the position command value 101 when the time change rate of the position command value 101 is a predetermined constant value. The time response simulation result of the position detection value 104 is shown in FIG. According to FIG. 14, as a result of superimposing a speed estimation error obtained by amplifying a variable position detection error synchronized with the true position x on the speed estimation value 105, the control command value 103 is also synchronized with the speed estimation error. It can be seen that the control accuracy of the true speed, which should be a constant value, is deteriorated.
In FIG. 14, the true position x indicated by a solid line and the position detection value 104 indicated by a broken line overlap each other.

Therefore, in the servo control device 100 (FIG. 11) according to the fourth embodiment, the dynamic characteristics from the control command value 103 to the position detection value 104, that is, the dynamic characteristics of the actuator 5, the control target 1, and the position detector 2 are It is assumed that the rigid body characteristic can be approximated in the frequency region including the speed control band of the servo control device 100.
The speed estimator 6a is configured by a Kalman filter given by the following Kalman gain, filter equation, and error covariance matrix equation.

As described above, in the servo control device 100 according to the fourth embodiment, the equivalent inertia obtained by approximating the dynamic characteristics from the control command value 103 to the position detection value 104 by the rigid body characteristics in the frequency region including the speed control band of the servo control apparatus 100. A speed estimator 6a is configured by a Kalman filter based on A and the sampling period _Td of the servo control device 100.

  In the servo control device 100 (FIG. 11) according to the fourth embodiment, the estimator given by the following disturbance estimator transfer function corresponding to the serial connection of the PI compensator and the phase advance compensator is used as the continuous transfer function. The disturbance estimator 12a is configured by the bilinearly transformed IIR filter.

  In the Kalman filter that constitutes the speed estimator 6a, the disturbance acting on the controlled object 1 is not considered. For this reason, an error occurs in the position estimation value 107 with respect to the position detection value 104 under a disturbance action. The disturbance estimator 12a estimates the disturbance estimated value 109a based on the position estimation error, and inputs the added value of the disturbance estimated value 109a and the control command value to the speed estimator 6a as a new control command value. With such a configuration, the estimation error of the position estimation value 107 with respect to the position detection value 104 converges to zero, and the influence of disturbance acting on the control target 1 is compensated.

On top of that, the servo control device 100 according to the fourth embodiment, as an operation at time kT _d, first, acquires the position detection value 104 of the control target 1 by the position detector 2.
Next, based on the position estimation error obtained by subtracting the one-sample delayed signal 108a (position estimation value at the previous time (k-1) _Td ), which is the output of the first delay unit 8a, from the position detection value 104, disturbance The estimator 12a calculates and outputs a disturbance estimated value 109a acting on the control target 1.
Furthermore, based on the position detection value 104, the disturbance estimated value 109a, and the one-sample delayed signal 108b (control command value at the previous time (k-1) _Td ) output from the second delay unit 8b, the speed estimator The speed estimation value 105 and the position estimation value 107 of the control target 1 are calculated and output by 6a.
The position controller 3 calculates and outputs the speed command value 102 based on the deviation between the position command value 101 and the position detection value 104.
Finally, based on the deviation between the speed command value 102 and the speed estimated value 105, the speed controller 4 and the control command limiter 7a calculate and output the control command value 103 for the controlled object 1.

  In this way, by estimating the speed estimation value 105 by the speed estimator 6a, even if the position detection value 104 fluctuates in a rectangular wave shape with the detection resolution (1LSB) of the position detector 2 as the minimum unit, the speed estimation value 105 Does not generate a spike-like speed estimation error, and the speed estimation accuracy for the true speed can be increased. Therefore, it is possible to improve the position control accuracy and the speed control accuracy of the servo control device 100 in the low-speed drive region where the operation speed of the control target 1 is near zero.

As an example, in the servo control device 100 according to the fourth embodiment, the time of the control command value 103, the true speed and speed estimated value 105, the true position x, and the position detection value 104 when the position command value 101 is a constant value. The response simulation result is shown in FIG.
In the time response simulation related to FIG. 13 and the time response simulation related to FIG. 12 of the conventional basic servo control apparatus 200, the vertical axis is the same scale, and the horizontal axis is the same scale.
In FIG. 13, the true speed indicated by a solid line and the speed estimated value 105 indicated by a broken line overlap each other.

  According to FIG. 13, even if the position detection value 104 fluctuates in a rectangular wave shape with the detection resolution (1LSB) as an amplitude, the speed estimation value 105 output from the speed estimator 6a has a spike as shown in FIG. Thus, the true speed is estimated with high accuracy. As a result, the fluctuation amount of the control command value 103 is greatly suppressed as compared with FIG. 12, and the control accuracy of the true speed that should be essentially zero and the true position x that should be essentially a constant value is greatly improved. I understand that

  Even when the position detection value 104 output from the position detector 2 includes a variable position detection error synchronized with the true position x, the variable speed estimation error superimposed on the speed estimation value 105 is suppressed. The speed estimation accuracy for the true speed can be increased. Therefore, it is possible to improve the speed control accuracy of the servo control device 100 in a region where the operation speed of the controlled object 1 is medium / high speed driving.

As an example, in the servo control apparatus 100 according to the fourth embodiment, the control command value 103, the true speed and the speed estimated value 105, the true position x, and the like when the time change rate of the position command value 101 is a predetermined constant value. The time response simulation result of the position detection value 104 is shown in FIG.
In the time response simulation related to FIG. 15 and the time response simulation related to FIG. 14 of the conventional basic servo control apparatus 200, the vertical axis is the same scale, and the horizontal axis is the same scale.
In FIG. 15, the true position x indicated by a solid line and the position detection value 104 indicated by a broken line overlap each other.

  According to FIG. 15, the fluctuating speed estimation error superimposed on the speed estimation value 105 is suppressed as compared with FIG. 14, and as a result, the fluctuation amount of the control command value 103 is also suppressed. Thereby, the control accuracy of the true speed, which should be a constant value, is also improved.

  Thus, according to the servo control device 100 according to the fourth embodiment, the disturbance estimator 12a estimates the disturbance acting on the controlled object 1 and is output from the disturbance estimated value 109a and the second delay unit 8b. The added value with the sample delay signal 108b is input to the speed estimator 6a as a new control command value. By setting it as such a structure, the influence of the disturbance which acts on the control object 1 can be compensated. Therefore, the accuracy of speed estimation with respect to the true speed can be increased regardless of the level of disturbance acting on the control target 1, and the position control accuracy of the servo control device 100 can be achieved in all drive regions including low speed and medium / high speed. In addition, the speed control accuracy can be improved. In other words, it is possible to achieve position control accuracy and speed control accuracy of the same level as in the past by the servo control device 100 to which the position detector 2 having a lower resolution than in the past is applied.

  Incidentally, the above-described fourth embodiment is merely an example, and it goes without saying that, for example, the control command limiter 7a shown in FIG. 11 is not necessarily implemented.

In this embodiment, the dynamic characteristics from the control command value 103 to the position detection value 104, that is, the dynamic characteristics of the actuator 5, the controlled object 1, and the position detector 2 are included in the speed control band of the servo control device 100. The velocity estimator 6a is composed of a Kalman filter, assuming that the region can be approximated by rigid body characteristics. The disturbance estimator 12a estimates the disturbance acting on the controlled object 1 and outputs the estimated disturbance value 109a. Then, in the speed estimator 6a, the position detection value 104, the disturbance estimation value 109a, and the control command value at the previous time (k-1) _Td are input, and the speed estimation value 105 of the control object 1 is estimated. Feedback was made to the speed controller 4.

  Thereby, even if the position detection value 104 fluctuates in a rectangular wave shape with the detection resolution (1LSB) of the position detector 2 as the minimum unit, a spike-like speed estimation error does not occur in the speed estimation value 105, and the control object 1 The speed estimation accuracy for the true speed can be increased regardless of the level of disturbance acting on the motor. Therefore, it is possible to improve the position control accuracy and the speed control accuracy of the servo control device 100 in the low-speed drive region where the operation speed of the control target 1 is near zero.

  In addition, even when the position detection value 104 by the position detector 2 includes a variable position detection error synchronized with the true position x, the variable speed estimation error superimposed on the speed estimation value 105 is suppressed, and the control target The speed estimation accuracy for the true speed can be increased regardless of the level of the disturbance acting on 1. Therefore, it is possible to improve the speed control accuracy of the servo control device 100 in a region where the operation speed of the controlled object 1 is medium / high speed driving.

  Therefore, it is possible to improve the position control accuracy and the speed control accuracy of the servo control device 100 in the entire drive region including the low speed and the medium high speed. In other words, it is possible to achieve position control accuracy and speed control accuracy of the same level as in the past by the servo control device 100 to which the position detector 2 having a lower resolution than in the past is applied.

In particular, in the fourth embodiment, in the frequency range including the speed control band of the servo control device 100, the equivalent inertia A in which the dynamic characteristics from the control command value 103 to the position detection value 104 are approximated by the rigid body characteristics, and the servo control. The velocity estimator 6a is configured by a Kalman filter constructed based on the sampling period _Td of the apparatus 100.

For this reason, a Kalman filter can be configured by the sampling period _Td of the servo control device 100 obtained as information with high accuracy and the equivalent inertia A determined with high accuracy based on the measurement result of the actual machine characteristics. In the speed estimator 6a, the speed estimation accuracy for the true speed can be further increased.

Embodiment 5 FIG.
Hereinafter, the fifth embodiment will be described with reference to the drawings.
FIG. 16 is a block diagram showing a configuration of the servo control device 100 according to the fifth embodiment. In FIG. 16, the same components as those in FIG. The meanings of the symbols shown in FIG. 16 are as follows. However, the description of the same symbols as those in FIG. 11 is omitted.

As shown in FIG. 16, in the servo control device 100 according to the fifth embodiment, the speed deviation between the speed command value 102 output from the position controller 3 and the speed estimated value 105 output from the speed estimator 6b. Is input to the speed deviation limiter 7b. Then, the speed deviation 106 obtained by performing the limit process on the speed deviation is input to the speed controller 4.
The speed controller 4 calculates and outputs the control command value 103 of the servo control device 100 based on the speed deviation 106 after the limit process output from the speed deviation limiter 7b.
The first delay unit 8a receives the position estimation value 107 output from the speed estimator 6b, and generates and outputs a one-sample delay signal 108a corresponding to the sampling period _Td .
The disturbance estimator 12b acts on the control object 1 based on the position estimation error obtained by subtracting the one-sample delay signal 108a that is the output of the first delay unit 8a from the position detection value 104 output from the position detector 2. The estimated disturbance is output as a disturbance estimated value 109b.
In the second delay unit 8c, the speed deviation 106 output from the speed deviation limiter 7b is input, and a one-sample delay signal 108c corresponding to the sampling period _Td is generated and output. The speed estimator 6b receives the position detection value 104 output from the position detector 2, the disturbance estimation value 109b output from the disturbance estimator 12b, and the one-sample delay signal 108c output from the second delay unit 8c. As a result, the speed and position x of the control object 1 are estimated and output as the speed estimated value 105 and the position estimated value 107.

Next, the operation of the servo control apparatus 100 according to the fifth embodiment will be described.
In the servo control device 100 (FIG. 16) according to the fifth embodiment, the dynamic characteristics from the speed deviation 106 to the position detection value 104, that is, the dynamic characteristics of the speed controller 4, the actuator 5, the control target 1, and the position detector 2. However, it is assumed that the rigid body characteristic can be approximated in the frequency region including the speed control band of the servo control device 100. The speed estimator 6b is configured by a stationary Kalman filter given by the following filter equation.

In general, when the system parameters F _k , G _k , D _k , and H _k of the controlled object 1 are given as time-invariant systems F, G, D, and H that do not depend on time, the Kalman filter converges to a steady-state constant Kalman filter. . In particular, if (F, G) is stable and (H, F) is detectable, the stationary Kalman filter is asymptotically stable.
In the servo control device 100 according to the fifth embodiment, the steady Kalman gain after the Kalman filter converges to the constant coefficient filter is applied using the above characteristics. And the speed estimator 6b is comprised by the stationary Kalman filter.

In the servo control device 100 according to the fifth embodiment, the dynamic characteristics from the speed deviation 106 to the position detection value 104, that is, the dynamic characteristics of the speed controller 4, the actuator 5, the controlled object 1, and the position detector 2 are It is assumed that the rigid body characteristic can be approximated in the frequency region including the speed control band of the servo control device 100. The speed estimator 6b is composed of a stationary Kalman filter based on the sampling period _Td of the servo control device 100 and the speed control system gain intersection frequency ω _rc (the third equation of the filter equation (prediction)).

On the other hand, in the servo control apparatus 100 according to the fifth embodiment, the continuous system transfer function is an estimation given by a disturbance estimator transfer function (refer to the fourth embodiment) corresponding to a series connection of a PI compensator and a phase advance compensator. The disturbance estimator 12b is constituted by an IIR filter obtained by bilinear transformation of the detector.
In the stationary Kalman filter constituting the speed estimator 6b, the disturbance acting on the controlled object 1 is not considered. For this reason, an error occurs in the position estimation value 107 with respect to the position detection value 104 under a disturbance action. The disturbance estimator 12b estimates the disturbance estimated value 109b based on this position estimation error, and inputs the added value of the disturbance estimated value 109b and the speed deviation to the speed estimator 6b as a new speed deviation. With such a configuration, the estimation error of the position estimation value 107 with respect to the position detection value 104 converges to zero, and the influence of disturbance acting on the control target 1 is compensated.

On top of that, the servo control device 100 according to the fifth embodiment, as an operation at time kT _d, first, acquires the position detection value 104 of the control target 1 by the position detector 2.
Next, based on the position estimation error obtained by subtracting the one-sample delayed signal 108a (position estimation value at the previous time (k-1) _Td ), which is the output of the first delay unit 8a, from the position detection value 104, disturbance The estimator 12b calculates and outputs a disturbance estimated value 109b acting on the controlled object 1.
Further, based on the position detection value 104, the disturbance estimated value 109b, and the one-sample delay signal 108c (speed deviation at the previous time (k−1) _Td ) output from the second delay unit 8c, the speed estimator 6b. Thus, the speed estimated value 105 and the position estimated value 107 of the controlled object 1 are calculated and output.
The position controller 3 calculates and outputs the speed command value 102 based on the deviation between the position command value 101 and the position detection value 104.
Next, a signal obtained by performing a limit process on the deviation between the speed command value 102 and the speed estimated value 105 is output as a speed deviation 106 from the speed deviation limiter 7b.
Finally, based on the speed deviation 106, the speed controller 4 calculates and outputs a control command value 103 for the control target 1.

As described above, according to the servo control apparatus 100 according to the fifth embodiment, the speed estimation value 105 is estimated by the speed estimator 6b having the above-described configuration, so that the dynamic characteristics from the control command value 103 to the position detection value 104, that is, Even when the equivalent inertia A obtained by approximating the dynamic characteristics of the actuator 5, the controlled object 1, and the position detector 2 by the rigid body characteristics changes, the speed controller 4 always provides a constant low frequency range control characteristic (speed control system gain). If the intersection frequency ω _rc ) can be realized, the following becomes possible. Specifically, the input to the stationary Kalman filter is the position detection value 104 output from the position detector 2, the disturbance estimated value 109b output from the disturbance estimator 12b, and the speed output from the second delay unit 8c. A one-sample delay signal 108c of deviation is assumed. As a result, the system to be estimated by the stationary Kalman filter is defined as the speed controller 4, the actuator 5, the control object 1, and the position detector 2, regardless of the level of the disturbance acting on the control object 1. It is possible to maintain the estimation accuracy of the speed estimation value 105 for the true speed.

In addition, the stationary Kalman filter in this case can be constructed based on the sampling period T _d of the servo control device 100 and the speed control system gain intersection frequency ω _rc .
In this case, as a speed deviation limit value in the speed deviation limiter 7b, a value obtained by equivalently converting the control command limit value in the control command limiter 7a shown in FIG. It is necessary to ensure sex.

Incidentally, the fifth embodiment is merely an example, and it goes without saying that, for example, the speed deviation limiter 7b shown in FIG. 16 is not necessarily mounted. In the fifth embodiment, the steady Kalman filter constituting the speed estimator 6b is constructed based on the sampling period _Td of the servo control device 100 and the speed control system gain intersection frequency _ωrc . However, in a frequency region including the speed control band of the servo control device 100, an equivalent inertia A approximating a dynamic characteristic from the control command value 103 to the position detection value 104 by a rigid body characteristic, a sampling period T _d of the servo control device 100, and it may be constructed on the basis of the proportional control gain K _D of the speed controller 4 (second formula of the filter equation (predicted)).

In this embodiment, the dynamic characteristics from the speed deviation 106 to the position detection value 104, that is, the dynamic characteristics of the speed controller 4, the actuator 5, the controlled object 1, and the position detector 2 are controlled by the speed control of the servo controller 100. It is assumed that the rigid body characteristics can be approximated in the frequency domain including the band. Then, by applying the steady Kalman gain after the Kalman filter converges to the constant coefficient filter, the speed estimator 6b is configured by the steady Kalman filter. Further, the disturbance acting on the controlled object 1 is estimated by the disturbance estimator 12b and output as a disturbance estimated value 109b. Then, the speed estimator 6b estimates the speed estimation value 105 of the control object 1 by using the position detection value 104, the disturbance estimation value 109b, and the speed deviation 108c at the previous time (k-1) _Td as input. Feedback was made to the deviation limiter 7b.

  As a result, the calculation amount in the speed estimator 6b is maintained while maintaining the estimation accuracy of the speed estimation value 105 for the true speed, that is, the position control accuracy and the speed control accuracy of the servo control device 100 at the same level as when the Kalman filter is applied. It can be greatly reduced.

In addition, in the fifth embodiment, on the assumption that a constant low frequency region control characteristic (speed control system gain intersection frequency ω _rc ) can always be realized by the speed controller 4 of the servo control device 100, the speed controller 4, A stationary Kalman filter was constructed with the actuator 5, the controlled object 1, and the position detector 2 as the target system. The speed estimator 6b configured by the stationary Kalman filter is configured to estimate and output the speed estimated value 105.

  Thus, even when the dynamic characteristic from the control command value 103 to the position detection value 104, that is, the equivalent inertia A that approximates the dynamic characteristic of the actuator 5, the control target 1, and the position detector 2 with the rigid body characteristic changes, It becomes possible to maintain the control accuracy of the speed estimated value 105 with respect to the true speed at an arbitrary equivalent inertia.

In particular, in this embodiment, the speed estimator 6b is configured by a steady Kalman filter constructed based on the sampling period _Td of the servo control device 100 and the speed control system gain intersection frequency _ωrc .

For this reason, the speed control system gain intersection frequency ω that is measured with high accuracy based on the sampling period T _d of the servo control device 100 that has conventionally been obtained as highly accurate information and the actual machine characteristics after the speed controller 4 is designed. _A stationary Kalman filter can be constituted by _rc . In the speed estimator 6b, the speed estimation accuracy for the true speed can be further increased.

Embodiment 6 FIG.
Hereinafter, the sixth embodiment will be described with reference to the drawings.
FIG. 17 is a block diagram showing a configuration of the servo control device 100 according to the sixth embodiment. In FIG. 17, the same components as those in FIG.

FIG. 18 shows the time response characteristics of the control command value, the true speed and the estimated speed value, the true position and the position detection value when the error of the position detection value is expanded for a certain period in the servo control device 100 according to the fifth embodiment. It is a time waveform figure which shows a simulation result.
FIG. 19 shows the time response characteristics of the control command value, the true speed and the estimated speed value, the true position and the position detection value when the error of the position detection value is expanded for a certain period in the servo control device 100 according to the sixth embodiment. It is a time waveform figure which shows a simulation result.

As shown in FIG. 17, in the servo control apparatus 100 according to the sixth embodiment, the first position signal selector 9 outputs the position detection value 104 output from the position detector 2 and the speed estimator 6b. Is selected based on the position selection signal output from the position selection signal controller 11 and is output as a position feedback signal to the position controller 3.
In the second position signal selector 10, either the position detection value 104 output from the position detector 2 or the one-sample delay signal 108a of the position estimation value output from the first delay unit 8a is obtained. A selection is made based on the position selection signal output from the position selection signal controller 11 and output as a speed estimator input signal.
The position selection signal controller 11 uses the first position signal based on the position detection value 104 output from the position detector 2 and the one-sample delay signal 108a of the position estimation value output from the first delay unit 8a. A position selection signal to be input to the selector 9, the second position signal selector 10, and the disturbance estimator 12b is generated and output.
The disturbance estimator 12b determines whether to execute or stop the disturbance estimation operation based on the position selection signal output from the position selection signal controller 11.
In the speed estimator 6b, the speed estimator input signal output from the second position signal selector 10, the disturbance estimated value 109b output from the disturbance estimator 12b, and the speed deviation output from the second delay unit 8c. Based on the one-sample delay signal 108c, the speed and position of the control target 1 are estimated and output as the speed estimated value 105 and the position estimated value 107.
The position controller 3 calculates the speed command value 102 of the servo controller 100 based on the deviation between the position command value 101 given from the outside and the position feedback signal output from the first position signal selector 9. Output.

Next, in the servo control device 100 according to the fifth embodiment, the operation when the error of the position detection value 104 with respect to the true position x is expanded for a certain period is shown, and then the operation of the servo control device 100 according to the sixth embodiment. Will be described.
In the servo control device 100 according to the fifth embodiment shown in FIG. 16, when the error of the position detection value 104 with respect to the true position x is expanded for a certain period due to the defective operation of the position detector 2, it is configured with a steady Kalman filter. The speed estimator 6b estimates the speed estimated value 105 based on the position detection value 104 on which an excessive error is superimposed. Therefore, the speed estimation accuracy for the true speed is degraded. At this time, the servo control device 100 performs position control and speed control by feeding back the position detection value 104 on which an excessive error is superimposed and the speed estimation value 105 whose estimation accuracy is deteriorated, even during a certain period. For this reason, the position control accuracy and the speed control accuracy are extremely deteriorated in accordance with the error amount superimposed on the position detection value 104 for a certain period.

As an example, in the servo control apparatus 100 according to the fifth embodiment, the error of the position detection value 104 is approximately 50 ms from the time 0.1 s with the time change rate of the position command value 101 set to a predetermined constant value. FIG. 18 shows a time response simulation result of the control command value 103, the true speed and the estimated speed value 105, the true position x, and the position detection value 104 when enlarged.
According to FIG. 18, the estimation accuracy of the speed estimation value 105 is extremely deteriorated in accordance with an excessive error superimposed on the position detection value 104, and the control command value 103 is greatly disturbed. In FIG. 18, the control command value 103 has reached the control command limit value corresponding to the speed deviation limiter 7b. Therefore, it can be seen that a period of approximately 0.15 s is required for the servo control device 100 to return to the normal operation with respect to the error expansion period (50 ms) in the position detection value 104.

  Therefore, in the servo control device 100 (FIG. 17) according to the sixth embodiment, the disturbance estimation operation in the disturbance estimator 12b is stopped during the error expansion period of the position detection value 104, and the position feedback signal to the position controller 3 is set in the position feedback signal. The estimated value 107 is applied, and the one-sample delayed signal 108a of the position estimated value is applied to the velocity estimator input signal to the velocity estimator 6b. Thereby, deterioration of the position control accuracy and the speed control accuracy of the servo control device 100 due to the defective operation of the position detector 2 is suppressed.

  Specifically, based on the position detection value 104 output from the position detector 2 by the position selection signal controller 11 and the one-sample delay signal 108a of the position estimation value output from the first delay unit 8a, Switch the position selection signal as follows.

  When the position selection signal is in the “normal” state and the following conditions are satisfied, the position selection signal controller 11 switches the position selection signal from “normal” to “abnormal” and holds it.

  After the position selection signal is switched to the “abnormal” state, the position selection signal is switched from “abnormal” to “normal” by the position selection signal controller 11 when the following conditions are satisfied.

In the disturbance estimator 12b, when the position selection signal output from the position selection signal controller 11 is “normal”, the disturbance estimation operation similar to that of the fifth embodiment is executed and the disturbance estimation value 109b is output.
On the other hand, when the position selection signal is switched to “abnormal” at the time kT _d , the disturbance estimator 12 b performs the disturbance estimation operation while holding the disturbance estimated value 109 b of (k−1) T _d immediately before switching. Stop.

  Based on the position selection signal output from the position selection signal controller 11, the first position signal selector 9 selects a position feedback signal that is output according to the following expression.

  In the second position signal selector 10, based on the position selection signal output from the position selection signal controller 11, the output speed estimator input signal is selected according to the following expression.

In the speed estimator 6b, the speed estimator input signal output from the second position signal selector 10, the disturbance estimated value 109b output from the disturbance estimator 12b, and the speed deviation output from the second delay unit 8c. Based on the one-sample delay signal 108c, the estimated speed value 105 and the estimated position value 107 of the controlled object 1 are estimated and output.
The position controller 3 calculates the speed command value 102 of the servo controller 100 based on the deviation between the position command value 101 given from the outside and the position feedback signal output from the first position signal selector 9. Output.

  As a result, when the position detection value 104 output from the position detector 2 is normal, the position feedback signal for the position controller 3 (the output of the first position signal selector 9) and the speed estimation for the speed estimator 6b. The position detection value 104 is applied as a conventional device input signal (output of the second position signal selector 10).

  On the other hand, when the error of the position detection value 104 is expanded for a certain period due to the defective operation of the position detector 2, the position is estimated in the position feedback signal (output of the first position signal selector 9) to the position controller 3. By applying the value 107 and applying the one-sample delay signal 108a of the position estimated value to the speed estimator input signal (output of the second position signal selector 10) to the speed estimator 6b, the position detector 2 is defective. Deterioration of position control accuracy and speed control accuracy of the servo control device 100 due to operation is suppressed.

As an example, in the servo control device 100 according to the sixth embodiment, the error of the position detection value 104 increases in a period of about 50 ms from the time 0.1 s with the time change rate of the position command value 101 set to a predetermined constant value. FIG. 19 shows the time response simulation results of the control command value 103, the true speed and the estimated speed value 105, the true position x, and the position detection value 104 in the case of the above.
In the time response simulation related to FIG. 19 and the time response simulation related to FIG. 18, the vertical axis is the same scale and the horizontal axis is the same scale. Further, the error amount superimposed on the position detection value 104 is also the same.

According to FIG. 19, even if the error of the position detection value 104 is expanded for a certain period due to the defective operation of the position detector 2, the speed estimation value 105 output from the speed estimator 6b is shown in FIG. Thus, the speed estimation accuracy is not deteriorated as described above, and the true speed is estimated with high accuracy.
By feeding back the position estimation value 107 and the speed estimation value 105 with greatly improved speed estimation accuracy to the position controller 3 and the speed deviation limiter 7b during the error expansion period of the position detection value 104, the control command value 103 It can be seen that the amount of fluctuation is also greatly suppressed as compared to FIG. 18, and the behavior of the servo control device 100 is maintained in a substantially normal operation.

  Note that the sixth embodiment described above is merely an example, and for example, it is needless to say that the speed deviation limiter 7b illustrated in FIG. In the sixth embodiment, the speed estimator 6b is configured with a stationary Kalman filter. However, the speed estimator 6b may be configured with the Kalman filter described in the fourth embodiment. Further, the input signal of the speed estimator 6b may be composed of a one-sample delay signal 108b of a control command value, a disturbance estimated value 109a, and a speed estimator input signal.

  In the sixth embodiment, during the error expansion period of the position detection value 104, the disturbance estimation operation in the disturbance estimator 12b is stopped, the position estimation value 107 is applied to the position feedback signal to the position controller 3, and the speed estimator By applying the one-sample delay signal 108a of the position estimation value to the speed estimator input signal to 6b, the deterioration of the position control accuracy and the speed control accuracy of the servo control device 100 due to the defective operation of the position detector 2 is suppressed. I tried to do it.

  Thereby, even when the error of the position detection value 104 with respect to the true position x is expanded for a certain period due to the defective operation of the position detector 2, the steady Kalman filter constituting the speed estimator 6b is changed to the true position x. The true speed is estimated with high accuracy and fed back to the servo controller 100. Therefore, it is possible to suppress deterioration of the position control accuracy and the speed control accuracy of the servo control device 100 during the period.

  In particular, in the sixth embodiment, the position selection signal controller 11 performs position selection when the absolute error value between the position detection value 104 and the one-sample delay signal 108a of the position estimation value is equal to or greater than the first threshold value. The signal is switched from “normal” to “abnormal” and held. Furthermore, when the error absolute value between the position detection value 104 and the one-sample delay signal 108a of the position estimation value has converged to the second threshold value or below, or when a preset return time has elapsed, the position selection signal “ Switch from “abnormal” to “normal” and hold.

  As a result, the discontinuous change in the operation switching of the disturbance estimator 12b and the first and second changes at both the switching timing by the error detection of the position detection value 104 and the switching timing by the normal operation return of the position detector 2. The discontinuous change in the output signal switching of the position signal selector can be minimized. Therefore, it is possible to minimize the deterioration of the position control accuracy and the speed control accuracy of the servo control device 100 due to the defective operation of the position detector 2. In addition, even when a preset return time has elapsed, the normal operation return of the position detector 2 is executed, thereby switching the operation of the disturbance estimator 12b and the output signals in the first and second position signal selectors. It becomes possible to execute switching reliably.

  1 control object, 2 position detector, 3 position controller, 4 speed controller, 5 actuator, 6a speed estimator, 6b speed estimator, 7a control command limiter, 7b speed deviation limiter, 8 delay unit, 8a first Delay unit, 8b, 8c second delay unit, 9 first position signal selector, 10 second position signal selector, 11 position selection signal controller, 12a, 12b disturbance estimator, 100 servo controller, 101 Position command value, 102 Speed command value, 103 Control command value, 104 Position detection value, 105 Speed estimation value, 106 Speed deviation, 107 Position estimation value, 108 1 sampling delay signal, 108a, 108b, 108c 1 sampling delay signal, 109a 109b Disturbance estimate, 200 Servo controller, 210 Speed estimator.

Claims (18)

A controlled object whose controlled variable is a position defined by translational displacement or rotational displacement;
A position detector that detects the position of the controlled object and outputs a position detection value;
A speed estimator that estimates a speed defined by a translation speed or a rotational speed of the control target based on at least the position detection value and outputs the speed as a speed estimation value;
A position controller that calculates and outputs a speed command value to be controlled based on a position command value given from the outside and the position detection value;
Based on the speed command value and the speed estimated value, a speed controller that calculates and outputs a control command value for a control target;
A servo control device comprising a control force for controlling translational displacement or an actuator for applying control torque for controlling rotational displacement based on the control command value;
The speed estimator is
It is composed of a Kalman filter based on dynamic characteristics from the control command value to the position detection value in a frequency region including the speed control band of the servo control device,
A servo control device, wherein the position detection value and the control command value are input and the speed estimation value of the control target is estimated and output. The speed estimator is
The Kalman filter is composed of a stationary Kalman filter that applies a stationary Kalman gain after convergence to a constant coefficient filter,
2. The servo control device according to claim 1, wherein the position detection value and the control command value are input and the speed estimation value of the control target is estimated and output. The Kalman filter or stationary Kalman filter constituting the velocity estimator is
The position detection value;
A speed deviation between the speed command value and the speed estimated value;
The servo control device according to claim 1, wherein the servo control device is configured to estimate and output the speed estimation value of the control target. The Kalman filter or stationary Kalman filter constituting the velocity estimator is
When the position detection value and the control command value are input,
Equivalent inertia approximating the dynamic characteristic from the control command value to the position detection value by a rigid body characteristic in a frequency region including the speed control band of the servo control device,
Configured based on the sampling period of the servo control device,
When inputting the speed deviation between the speed command value and the speed estimated value,
Equivalent inertia approximating the dynamic characteristic from the control command value to the position detection value by a rigid body characteristic in a frequency region including the speed control band of the servo control device,
The sampling period of the servo controller;
The servo control device according to any one of claims 1 to 3, wherein the servo control device is configured based on a proportional control gain in the speed controller. The Kalman filter or stationary Kalman filter constituting the velocity estimator is
Speed control system gain intersection frequency realized by the speed controller,
The sampling period of the servo controller;
4. The servo control device according to claim 3, wherein the servo control device is configured based on the above. The Kalman filter or stationary Kalman filter constituting the velocity estimator is
In addition to the estimated speed value, the estimated position value of the controlled object is estimated and output,
The servo control device further comprises:
A delay unit that generates and outputs a delay signal of the position estimation value;
A first position signal selector that selects one of the position estimation value and the position detection value based on a position selection signal and outputs the position feedback signal;
A second position signal selector that selects one of the delay signal of the position estimation value output from the delay unit and the position detection value based on the position selection signal and outputs the selected signal as a speed estimator input signal. When,
Position selection for generating and outputting the position selection signal for input to the first position signal selector and the second position signal selector based on the speed estimator input signal and the position detection value A signal controller;
With
The Kalman filter or stationary Kalman filter constituting the velocity estimator is
The speed estimator input signal;
With the control command value or the speed deviation between the speed command value and the speed estimated value as input, the position estimated value and the speed estimated value of the control target are estimated and output,
The position controller is
3. The servo control according to claim 1, wherein the speed command value is calculated and output based on the position command value given from outside and the position feedback signal. apparatus. The delay device is
7. The servo control device according to claim 6, wherein a 1-sample delay signal corresponding to a sampling period of the servo control device is generated and output as a delay signal of the position estimation value. The position selection signal controller is
When the error absolute value between the speed estimator input signal and the position detection value is equal to or greater than a first threshold,
The first position signal selector selects and outputs the position estimate as the position feedback signal;
The second position signal selector switches and holds the position selection signal so as to select and output the delayed signal of the position estimation value as the speed estimator input signal;
Furthermore, when the error absolute value between the speed estimator input signal and the position detection value converges below a second threshold value, or when a preset return time has elapsed,
The first position signal selector selects and outputs the position detection value as the position feedback signal;
The second position signal selector is configured to switch and hold the position selection signal so as to select and output the position detection value as the speed estimator input signal. 6. The servo control device according to 6. A controlled object whose controlled variable is a position defined by translational displacement or rotational displacement;
A position detector that detects the position of the controlled object and outputs a position detection value;
A speed estimator that estimates a speed and a position defined by a translation speed or a rotational speed of the control target based on at least the position detection value, and outputs the speed estimation value and the position estimation value;
A position controller that calculates and outputs a speed command value to be controlled based on a position command value given from the outside and the position detection value;
Based on the speed command value and the speed estimated value, a speed controller that calculates and outputs a control command value for a control target;
An actuator for applying a control force for controlling translational displacement or a control torque for controlling rotational displacement based on the control command value;
A first delay unit that generates and outputs a delay signal of the position estimation value;
A disturbance estimator that estimates a disturbance acting on the control target based on the position detection value and a delay signal of the position estimation value output from the first delay unit, and outputs the disturbance estimation value;
A second delay unit that generates and outputs a delay signal of the control command value;
In the servo control device with
The speed estimator is
In the frequency region including the speed control band of the servo control device, the Kalman filter based on the dynamic characteristics from the control command value to the position detection value,
The position detection value, the disturbance estimation value, and the delay signal of the control command value output from the second delay device are input, and the speed estimation value and the position estimation value of the control target are estimated and output. Servo control device. The speed estimator is
The Kalman filter is composed of a stationary Kalman filter that applies a stationary Kalman gain after convergence to a constant coefficient filter,
The position detection value, the disturbance estimation value, and the delay signal of the control command value output from the second delay device are input, and the speed estimation value and the position estimation value of the control target are estimated and output. The servo control device according to claim 9. The second delay device is
Using as input the speed deviation obtained by subtracting the speed estimated value from the speed command value, generating and outputting a delay signal of the speed deviation,
The Kalman filter or stationary Kalman filter constituting the velocity estimator is
The position detection value, the disturbance estimation value, and the speed deviation delay signal output from the second delay unit are input, and the speed estimation value and the position estimation value of the control target are estimated and output. The servo control device according to claim 9 or 10, wherein The Kalman filter or stationary Kalman filter constituting the velocity estimator is
When the position detection value, the disturbance estimated value, and the delay signal of the control command value output from the second delay device are input,
Equivalent inertia approximating the dynamic characteristics from the control command value to the position detection value by the rigid body characteristics in the frequency domain including the speed control band of the servo control device,
Configured based on the sampling period of the servo controller,
When the position detection value, the disturbance estimation value, and the delay signal of the speed deviation output from the second delay device are input,
Equivalent inertia approximating the dynamic characteristics from the control command value to the position detection value by the rigid body characteristics in the frequency domain including the speed control band of the servo control device,
The sampling period of the servo controller;
12. The servo control device according to claim 9, wherein the servo control device is configured based on a proportional control gain in the speed controller. The Kalman filter or stationary Kalman filter constituting the velocity estimator is
Speed control system gain intersection frequency realized by the speed controller,
The sampling period of the servo controller;
The servo control device according to claim 11, wherein the servo control device is configured based on the above. The first delay is
10. The servo control device according to claim 9, wherein a one-sample delay signal corresponding to a sampling period of the servo control device is generated and output as the delay signal of the position estimation value. The second delay device is
10. A one-sample delay signal corresponding to a sampling period of the servo control device is generated and output as the control command value delay signal or the speed deviation delay signal. The servo control device according to claim 11. The disturbance estimator is
It consists of a series connection of a PI compensator and a phase lead compensator,
12. A disturbance estimation value acting on the control target is estimated and output using a position estimation error obtained by subtracting a delay signal of the position estimation value from the position detection value as input. The servo control device according to any one of claims. The disturbance estimator is
Configured to determine the execution or stop of the disturbance estimation operation based on the position selection signal;
The servo control device further comprises:
A first position signal selector that selects one of the position detection value and the position estimation value based on the position selection signal and outputs the position detection signal as a position feedback signal to the position controller;
A second position signal that selects either one of the position detection value and a delay signal of the position estimation value output from the first delay unit based on the position selection signal and outputs it as a speed estimator input signal A selector,
Input to the first position signal selector, the second position signal selector, and the disturbance estimator based on the position detection value and the delay signal of the position estimation value output from the first delay unit. A position selection signal controller that generates and outputs the position selection signal for
With
The Kalman filter or stationary Kalman filter constituting the velocity estimator is
The speed estimator input signal from the second position signal selector, the disturbance estimation value, and the control command value or speed deviation delay signal output from the second delay unit are input, and the control target Estimate and output velocity and position estimates,
The position controller is
The speed command value is calculated and output based on the position command value given from the outside and the position feedback signal from the first position signal selector. The servo control device according to any one of claims 9 to 11. The position selection signal controller is
When the absolute error value between the position detection value and the delay signal of the position estimation value output from the first delay device is equal to or greater than a first threshold value,
The disturbance estimator stops the disturbance estimation operation while holding the previous disturbance estimated value,
The first position signal selector selects and outputs the position estimate;
The second position signal selector switches and holds the position selection signal so as to select and output the delay signal of the position estimation value output from the first delay device,
After the position selection signal is switched, the error absolute value of the position detection value and the delay signal of the position estimation value output from the first delay unit converges below a second threshold value, or the position When the preset return time has elapsed after switching the selection signal,
The disturbance estimator performs a disturbance estimation operation,
The first position signal selector selects and outputs the position detection value;
18. The servo control apparatus according to claim 17, wherein the second position signal selector switches and holds the position selection signal so as to select and output the position detection value.

Images