JP2023090071A - Servo system and servo system control method - Google Patents

Abstract

To enable continuous operation of a servomotor using an estimated measurement value obtained from a visual sensor even when an encoder is abnormal.SOLUTION: A servo system comprising a servomotor equipped with an encoder and a servo amplifier that controls the servomotor using a measured value of the encoder, is provided with a visual sensor for capturing an image of a controlled object driven by a servomotor and an ambient environment detector for detecting the ambient environment. The servo amplifier calculates a first estimated measurement value corresponding to the measurement value of the encoder based on an input image, determines soundness of data of the first estimated measurement value if the encoder is normal and stores the ambient environment data as guarantee-able environment data if the soundness is present. Then, if the encoder is abnormal, the servo amplifier compares the input ambient environment data with already stored guarantee-able environment data, and if applicable data is present, the servo amplifier controls the servo motor using the first estimated measurement value.SELECTED DRAWING: Figure 1

Description

The present invention relates to a servo system and a control method for the servo system.

Servo systems are widely used in various industrial fields. In general, a servo system consists of a servomotor equipped with an encoder that outputs (measures) the rotational speed and position of the motor, and feedback of the encoder output, and a power output that eliminates the difference between the encoder output and the operation command. to the servomotor to control the servomotor.

In such a servo system, conventionally known is a technique of detecting (determining) whether or not the output of the encoder is normal, and stopping the servomotor when the output of the encoder is abnormal. For example, Japanese Patent Application Laid-Open No. 2010-284781 (Patent Document 1) discloses that in a servo system that drives a robot, a visual sensor that captures an image of a target within the field of view is attached to an arm, and the image captured by the visual sensor is captured. The first measured value obtained by image processing is compared with the second measured value obtained from the encoder, and if the compared difference exceeds a set threshold value, it is determined that the encoder is abnormal, and the servo A technique for stopping a motor is disclosed.

JP 2010-284781 A

In the above-described conventional servo system (for example, Patent Document 1), an encoder abnormality is detected and the servomotor is stopped when the encoder abnormality is detected. It is possible to realize a highly safe servo system.

However, in the conventional servo system, when the encoder is abnormal, the servo motor is uniformly (without exception) stopped, so the servo system cannot be operated continuously when the encoder is abnormal. For this reason, servo systems used in production lines and the like still have the problem of a decrease in operating rate and a decrease in productivity.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to operate a servo motor using an estimated measurement value obtained from a visual sensor when it is determined that a condition for ensuring safety is satisfied even when an encoder is abnormal in a servo system. To provide a servo system and a method for controlling the servo system that can control and continue the servo system.

In order to solve the above problems, the present invention provides, for example, a servo system comprising a servo motor having an encoder and a servo amplifier for controlling the servo motor using the measured value of the encoder. a visual sensor for capturing an image of an object to be controlled driven by the servomotor; and an ambient environment detector for detecting an ambient environment of the servo system, wherein the servo amplifier detects the image and the ambient environment. and calculating a first estimated measured value corresponding to the measured value based on the image, and the difference between the measured value and the first estimated measured value is within a predetermined threshold during a period in which the encoder is normal. If the data is sound, the ambient environment data is stored as guarantable environment data, and if the encoder is determined to be abnormal, the input The servo system compares the stored ambient environment data with the stored guarantable environment data, and controls the servo motor using the first estimated measured value when the corresponding guarantable environment data exists. .

In order to solve the above problems, another example of the present invention is a servo motor having a servomotor equipped with an encoder and a servo amplifier for controlling the servomotor using the measured value of the encoder. A method for controlling a system, in which an image of a controlled object driven by the servomotor is captured using a visual sensor, and ambient environment data of the servo system is captured using an ambient environment detection unit, and the measurement is performed based on the image. Calculate the first estimated measured value corresponding to the value,
During a period in which the encoder is normal, the soundness of the data is determined by whether or not the difference between the measured value and the first estimated measured value is within a predetermined threshold value, and if the soundness is present, the Surrounding environment data is stored as guarantable environment data, and when it is determined that the encoder is abnormal, the input surrounding environment data and the guarantable environment data are collated, and the corresponding guarantee is performed. In the servo system control method, the servo motor is controlled using the first estimated measurement value when possible environment data exists.

According to the present invention, in the servo system, the soundness of the estimated measurement value obtained from the visual sensor is determined while the encoder is normal, and the ambient environment data in the case of soundness is stored as the guarantable environment data. If the encoder malfunctions, the servo motor is controlled by the estimated measurement value estimated from the image of the visual sensor if the input ambient environment data corresponds to the stored guaranteeable environment data. Therefore, the servo system can be operated continuously.

It is a figure which shows the structure of the servo system in Example 1 of this invention. It is a figure which shows an example of the ambient environment data which is stored. FIG. 7 is a diagram showing an operation flow of the arithmetic processing unit when the encoder is normal; FIG. 7 is a diagram showing an operation flow of the arithmetic processing unit when the encoder is abnormal; FIG. 10 is a diagram showing the configuration of a servo system in Example 2;

Hereinafter, embodiments (examples) of the present invention will be described in detail with reference to the drawings. Here, the present invention should not be construed as being limited to the contents of the examples described below. Those skilled in the art will easily understand that the configuration can be changed without departing from the technical idea or gist of the present invention.

In addition, in the configurations of the embodiments described below, the same reference numerals may be used in common for the same devices or parts having similar functions in different drawings, and redundant description may be omitted. In addition, the position, size, shape, range, etc. of each component shown in the drawings do not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. Accordingly, the present invention is not limited to the location, size, shape, extent, etc. of components disclosed in the drawings.

<<Example 1>>
Next, Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 is a diagram showing the configuration of a servo system according to the first embodiment. FIG. 2 is a diagram illustrating an example of ambient environment data stored in a storage unit; 3 and 4 are diagrams showing the operation flow of the servo system in the first embodiment.

First, the overall configuration of the servo system of the embodiment will be described with reference to FIG. In FIG. 1, the servo system 1 has a servomotor 20 having an encoder 21 and a servo amplifier 10 that controls the servomotor 20 . Further, in the system of the first embodiment, the servo amplifier 10 and the host controller 50 are communicably connected.

In addition, in the first embodiment, the visual sensor 30 is installed so as to capture an image of temporal fluctuations (moving state) of the controlled object driven and controlled by the servomotor, and the ambient environment for detecting the ambient environment of the servo system. A detection unit 40 is provided. A visual sensor 30 is installed so as to capture an image for estimating the measurements made by the encoder. For example, a visual sensor is installed at a place (position, posture) where the movement of a controlled object driven by a servomotor can be captured in an image. The ambient environment detection unit 40 detects physical quantity data that affects the image of the visual sensor.

Here, the "surrounding environment" refers to the conditions around the servo system, particularly the environment that affects the image captured by the visual sensor. "Ambient environment data" is data indicating physical quantities in the surrounding environment. Specific examples of ambient environment data include the intensity of light (illuminance) that affects the content of images captured by the visual sensor, the amount of dust (dust amount) at the location where the visual sensor is installed, and the degree of dirt on the lens of the visual sensor. be. Further, the "shooting conditions" of the visual sensor specifically refer to the orientation of the camera lens, the focal length, the zoom amount, and the like. In the embodiment, the visual sensor measures (detects) the surrounding environment data when the image of the servo system is taken, but it is not necessary to measure all the physical data such as the intensity of light, the amount of dust, and the degree of dirt on the lens. No matter what, one of these physical quantities may be selected and measured. Similarly, the photographing condition may be obtained by obtaining all of the camera lens orientation, focal length, and zoom amount, but basically, it is also possible to select any one of them.

The servo amplifier 10 in this embodiment includes a motor control unit 11 that feeds back the output of an encoder 21 (measured values of motor speed and position) and controls power supplied to the servo motor 20, an arithmetic processing unit 12, and a storage unit. and a portion 14 . Note that the current sensor 13 is a sensor that detects the current supplied to the motor. Although the current sensor is usually installed in the motor control unit 11 and used for feedback control of current control in many cases, it is described outside the motor control unit 11 here.

When the encoder 21 is normal, the motor control unit 11 feeds back speed/position data (hereinafter referred to as measurement value) A0 measured by the encoder 21 via the switching unit 110, and outputs the measurement value of the encoder 21. The deviation between A0 and the motor operation command S is obtained, and the controller 111 supplies electric power to the servomotor 20 so as to eliminate this deviation, thereby controlling the speed and position of the servomotor 20. FIG. Therefore, when the encoder 21 is normal (while it is determined to be normal), the switching unit 110 is switched to the input side of the measured value A0 of the encoder. When it is determined that the encoder 21 is abnormal, the switch signal C from the arithmetic processing unit 12 causes the switching unit 110 to change the estimated measured value (hereinafter referred to as first estimated measured value) A1 obtained from the image of the visual sensor. can be supplied to the motor control unit 11 .

The arithmetic processing unit 12 gives an operation command S to the motor control unit 11, and inputs the measured value A0 of the encoder, the image G captured by the visual sensor, the surrounding environment KD, and the current I to be supplied to the servomotor 20.

First, in this servo system, while the servomotor 20 is operating, it is determined at predetermined timings whether or not the encoder 21 is normal. Also, based on the input image G, a first estimated measured value A1 corresponding to the measured value A0 is calculated. During the period in which the encoder 21 is determined to be normal (during the period in which the encoder is normal) based on the abnormality determination (abnormality detection) of the encoder, the difference between the measured value A0 and the first estimated measured value A1 is determined in advance. It judges whether or not it is within a set threshold, and judges the soundness of the data.

Then, when the first estimated measurement value A1 is determined to be sound, the ambient environment data KD is stored in the storage unit 14 as "assurable environment data". This calculation, determination, and storage operation are performed at fixed time intervals during the period when the encoder 21 is normal.

When the encoder 21 is determined to be abnormal, the arithmetic processing unit 12 compares (collates) the input ambient environment data KD with the guarantable environment data stored in the storage unit 14 during the encoder normal period. . As a result, if there is a first estimated measured value A1 that matches the input ambient environment data KD among the first estimated measured values A1, the current first estimated measured value can be used for motor control. We judge that it is. In that case, instead of the measured value A0 of the encoder 21, the first estimated measured value A1 is supplied to the motor control section 11. FIG. Specifically, the switching signal C and the first estimated measured value A1 are output to the motor control section 11 . Thereby, the motor control section 11 can switch the switching section 110 and control the operation of the servo motor 20 using the first estimated measurement value A1. That is, even when the encoder is abnormal, if the ambient environment is the same as or equivalent to the ambient environment in which the soundness was determined in the normal state, the servomotor continues to operate.

Further, when it is determined that the encoder 21 is abnormal, if the arithmetic processing unit 12 determines that the input ambient environment data KD does not correspond to the stored guarantable environment data, the first estimation It judges that the accuracy of the measured value is low and cannot be used for motor control, and outputs a motor stop signal ST to the motor control unit 11 . The motor control unit 11 stops the servomotor 20 by cutting off the power supply to the motor in response to the stop signal ST.

In this way, even when the encoder 21 is abnormal, the servo system 1 can continue operation if it determines that certain conditions for ensuring safety are satisfied. A detailed description of a specific configuration of such an arithmetic processing unit 12 and a series of arithmetic processing operations will be given later.

Next, a more detailed configuration of the arithmetic processing unit 12 will be described. The arithmetic processing unit 12 can be specifically realized by a computer, a processor, or the like having a calculation function. Here, the arithmetic processing unit 12 includes a ROM 121 that stores programs, a RAM that temporarily stores various information (data) for arithmetic processing, and an image that performs image processing for estimating measurement values for an input image. A processing unit 123, a CPU 124 that executes a series of arithmetic processing based on a program, a setting unit 125 for setting information, and an input/output control for mutual communication of information with the host controller 50. Realize with /O126. Devices in the arithmetic processing unit 12 are connected by a bus 127 capable of mutual communication. The storage unit 14 and the arithmetic processing unit 12 are also connected by a bus so as to be mutually communicable.

For the image processing unit 123, it is preferable to use a dynamically reconfigurable processor (DRP) capable of processing image data at high speed. A DRP (dynamically reconfigurable processor) is hardware that executes an application while dynamically switching connections between computing units. Note that the DRP itself is known, and a detailed description thereof will be omitted here.

With the configuration as described above, the arithmetic processing unit 12 stores various information (data) in the storage unit 14, and stores information (data) stored in the internal memory and various information stored in the storage unit 14. It takes in and executes a series of arithmetic processing.

Next, the operation of the first embodiment shown in FIG. 1 will be explained using FIGS. 1 to 4. FIG.

First, in FIG. 1, the servo amplifier 10 inputs the measured values (velocity/position of the motor) of the encoder 21 . The input measured value is normally input to the motor control unit 11 and also input to the arithmetic processing unit 12 at the same time.

On the other hand, in synchronism with the input of the measured value from the encoder 21, the arithmetic processing unit 12 detects the image captured by the visual sensor 30, the surrounding environment detected by the surrounding environment detection unit 40, and the current detected by the current sensor 13. input. In addition, the photographing conditions of the visual sensor 30 are also taken into the arithmetic processing section 12 . The imaging conditions may be configured as part of the ambient environment detection unit 40 . Alternatively, it may be set from the setting unit 125 . These pieces of information (data) are temporarily stored in the internal RAM 122 and then stored in the storage unit 14 by the processing operation of the CPU 124 .

First, the arithmetic processing unit 12 (CPU 124) executes abnormality determination (abnormality detection) processing for determining whether the encoder 21 is normal. This abnormality determination method itself is well known (see JP-A-2005-198467, JP-A-5-344775, JP-A-2001-333590, JP-A-2002-350184, WO2019/031219, etc.). Moreover, the method described in the above-mentioned patent document 1 may be used. A detailed description of this abnormality determination is omitted.

Next, when the encoder is normal, the arithmetic processing unit 12 (CPU 124) uses the image data processed by the image processing unit 123 and stored in the RAM 122 to obtain the encoder measurement values (motor speed/position). Estimate the corresponding physical quantity. Since this estimation calculation method using images is also well known, the description thereof is omitted here. For example, a method such as that disclosed in Patent Document 1 may be used. Hereinafter, the motor speed/position value calculated based on this image is referred to as "first estimated measured value A1" because it is an estimated value corresponding to the measured value by the encoder. Here, the reason why the estimated value from the image is referred to as the "first estimated measured value" is to distinguish it from the estimated value estimated from the current.

Next, the arithmetic processing unit 12 (CPU 124) obtains the difference between the first estimated measurement value A1 and the encoder measurement value A0, and determines whether or not this difference exceeds a pre-stored threshold value. If the difference does not exceed the threshold, it is determined that the first estimated measurement value A0 obtained based on the image G captured by the visual sensor 30 is healthy.

In this embodiment, based on the motor current I, a "second estimated measured value A2", which is an estimated value corresponding to the measured value (motor speed/position) of the encoder 21, is also calculated. In addition to judging soundness by comparing the first estimated measured value A1 and the measured value A0 of the encoder, the difference between the first estimated measured value A1 and the second estimated measured value A2 is used as a threshold value. Use judgment to compare with. That is, the soundness of the first estimated measured value A1 is determined using not only the encoder measured value A0 but also the second estimated measured value A2. This makes the health determination more accurate.

Then, when it is determined that "soundness exists" by such a soundness determination, the ambient environment data KD stored in the RAM 122, the encoder measurement values, the estimated measurement values calculated based on the image, etc. It is stored in the storage unit 14 as "assurable environment data". If the first estimated measured value A1 is determined to be "no soundness" as a result of the soundness judgment, the ambient environment data is stored in the storage unit 14 as unguaranteed environment data (non-guaranteable environment data). Specifically, for example, information of "1" if it can be guaranteed and "0" if it cannot be guaranteed is used as judgment information, and the judgment information is stored together with the ambient environment data KD. Thereby, it is possible to distinguish whether the ambient environment data KD is "assurable environment data" or "unassurable environment data". In addition, in this embodiment, when storing the environment data, "calibration data" used when adjusting (correcting) the first estimated measurement value and the visual sensor are also stored as a set. Details of this will be described later.

Next, an example of information (environmental data and calibration data) stored in the storage unit 14 will be described with reference to FIG. FIG. 2 shows an example of information (data) recorded by the storage unit 14, which is stored as a data set for each mode. That is, the measured value A0 of the encoder, the first estimated measured value A1 estimated based on the image of the visual sensor, and the second estimated measured value A2 estimated based on the electric current are stored together with the surrounding environment data KD. be.

The environment data KD also stores information as to whether accuracy can be guaranteed or not. This information is stored as "environmental data that can be secured" when it is determined that the first estimated measured value is sound. In other words, it can be determined that the stored ambient environment is "environmental data that can be guaranteed" based on this accuracy-assurable information. In this example, the environmental data to be stored are light intensity, dust amount, and lens contamination. Physical data actually measured may be stored, but here, each physical quantity is divided into a plurality of levels and stored. For example, in the case of light intensity, the intensity is classified into five levels from strong to weak, and the corresponding level is stored instead of the actual intensity. By performing and storing such level divisions, it is possible to efficiently carry out a matching operation when the encoder is abnormal.

Also, in FIG. 2, calibration data is stored in addition to these data. In the example of FIG. 2, two types of data are stored. The first is "estimated value correction data" and the second is "visual sensor adjustment data". Specifically, the data for estimated value correction is the difference between the measured value A0 of the encoder and the first estimated measured value A1 estimated based on the image, and the ratio thereof. The data for adjusting the visual sensor are the direction, zoom, and focal length of the visual camera.

These calibration data are used when performing adjustment (calibration) when it is determined that the encoder 21 is abnormal. Specifically, when the arithmetic processing unit 12 outputs the first estimated measured value A1 to the motor control unit 11, it adjusts the first estimated measured value A1 using data for correcting the estimated value and outputs the adjusted first estimated measured value A1. For example, when using the difference between both measured values, the value obtained by subtracting this difference from the raw first estimated measured value A1 calculated based on the image is used as the first estimated measured value A1 after adjustment, and the motor control This adjustment is such that the data is output to the unit 11 . When the ratio is used, the calculated raw first estimated measured value A1 is multiplied by this ratio, and the adjusted first estimated measured value A1 is output to the motor control unit 11. . Also, the data for photographing correction is used to adjust the orientation, focus, etc. of the visual sensor. In FIG. 1, the dashed line connecting the arithmetic processing unit 12 to the visual sensor 30 indicates that the visual sensor 30 is adjusted.

Note that this calibration data may be stored in the storage unit 14 together with the certifiable environment data as shown in FIG. may be stored separately from the certifiable environment data in the storage unit. However, in that case, it is necessary to associate each piece of guarantable environment data with each piece of calibration data so that they can be associated with each other. Moreover, although FIG. 2 shows an example in which two types of calibration data are stored, it is also possible to store any one type of data.

Next, the operation of the servo amplifier 10 in FIG. 1 (basically, the operation of the arithmetic processing section 12) will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 is an operational flow when the encoder 21 is normal, and FIG. 4 is an operational flow when the encoder 21 is abnormal.

First, referring to FIG. 3, the operation of the arithmetic processing unit 12 when the encoder 21 is normal will be described.
In step S101 of FIG. 3, it is diagnosed whether the encoder is normal. In S102, the result of this diagnosis is used to determine whether the encoder 21 is normal or abnormal, and when the encoder 21 is normal, the process proceeds to step S103. If it is determined that the encoder 21 is abnormal, the process advances to step S200 to execute the processing operation when the encoder is abnormal. Details of the operation when the encoder is determined to be abnormal will be described later with reference to FIG.

In step S103 of FIG. 3, data measurement values, images, currents, and ambient environment data are input and stored at predetermined timings. In step S104, the first estimated measured value A1 is calculated from the image captured by the visual sensor 30, and the second estimated measured value is calculated from the current.

Next, in step S105, the soundness of the data of the first estimated measured value A1 is determined. Judgment compares the first estimated measurement value and the measurement value of the encoder, and judges that soundness exists when the difference is within the threshold. Also, the first estimated measured value and the second estimated measured value are compared to determine the soundness of the first estimated measured value A1. If any of them exceeds the threshold, it is determined that the first estimated measured value A1 is not sound.

If it is determined in the next step S106 that the data of the first estimated measured value A1 is sound, the process proceeds to step S107. When it is judged that there is no soundness, it progresses to step S109.

In step S107, the ambient environment when it is determined to be sound is stored in the storage unit 14 as guarantable environment data together with the measured value A0, the first estimated measured value A1, and the second estimated measured value A2 at that time. . Also, at that time, the calibration data is stored as shown in step S108. The contents are as shown in FIG. Further, in step S109, the ambient environment when it is determined that there is no soundness is stored as unguaranteable environment data together with the measured value A0, the first estimated measured value A1, and the second estimated measured value A2 at that time. . Incidentally, when it is determined that there is no soundness, the calibration data may or may not be stored.

Next, in step S110, it is determined whether or not the servomotor 20 is being driven at that time. If the servomotor 20 is being driven, the process returns to step S101 and continues the operations from step S101 to step S110.

In this manner, when the encoder 21 is normal, the arithmetic processing unit 12 stores the information shown in FIG. 2 in the storage unit 14 at predetermined timings. If the contents to be stored one after another are the same as the contents already stored, it is convenient not to store new information. In this way, the number of sets of assurable environment data stored in the storage unit 14 does not increase more than necessary, and even if the encoder 21 is abnormal, the environment data and the stored assureable environment data will not increase. Comparison and collation can be efficiently performed.

Next, referring to FIG. 4, the operation when the encoder 21 is abnormal (NO in step S102 of FIG. 3) will be described.

In FIG. 4, in step S201, data input is continued in the same manner as when the encoder is normal. At least the input of the image G and the ambient environment data KD continues.

In step S202, a first estimated measurement value is calculated based on the image G. In step S203, the ambient environment data input after the encoder abnormality determination is compared with the "environment data that can be guaranteed" stored when the encoder is normal. If the surrounding environment at that point in time corresponds to (applies to) the assurable environment data, the first estimated measurement value at that point satisfies the condition that it is an estimated value in an environment in which accuracy can be guaranteed.

In step S205, the results of the comparison and reference are checked to determine whether or not the input ambient environment corresponds to (is included in) the guarantable environment data. move on. As a result of the comparison and reference, if the input surrounding environment does not correspond to the stored guaranteeable environment data (there is no corresponding data), the process proceeds to step S208.

In step S205, calibration data (estimated value correction data shown in FIG. 2) is used to calibrate the first estimated measured value calculated in step S202. That is, the calculated first estimated measured value A1 is corrected (adjusted).

Then, in step S206, the corrected first estimated measurement value A1 is output to the motor control section 11 together with the switching signal C. FIG. As a result, the motor control unit 11 stops the feedback input of the measured value A0 (abnormal state) of the encoder 21 and switches to input the first estimated measured value A1 output by the arithmetic processing unit 12 . 1 is switched by the switching signal C, and the first estimated measured value A1 is input to the motor control section 11. By this switching, the motor control section 11 can control the servo motor 20 using the first estimated measured value A1 supplied from the arithmetic processing section 12 . That is, the operation of the servo system 1 can be continued.

In the next step S207, it is determined whether or not the servomotor 20 is in operation. If the servo motor 20 is in operation, the process returns to step S201 to repeat the above-described operations.

On the other hand, in step S204, if the input ambient environment data does not correspond to the certifiable environment data, the operation of step S208 is executed. That is, it determines that the accuracy (reliability) of the calculated first estimated measurement value is low, and outputs a stop command ST for the servomotor 20 to the motor control section 11 . In response to this stop command, the motor control unit 11 cuts off the power supplied to drive the servomotor 20 to stop the servomotor 20 .

As described above, according to the servo system of the first embodiment, the servo amplifier 10 receives an image from the visual sensor and the surrounding environment, and based on the image, the first estimated measured value corresponding to the encoder measured value (velocity/position). is calculated, and when the encoder is normal, the soundness of the data is determined by whether the difference between the measured value of the encoder and the first estimated measured value is within a predetermined threshold value. The ambient environment data input at that time is stored as guarantable environment data, and when the encoder is determined to be abnormal, the input ambient environment data corresponds to the guarantable environment data stored when the encoder is normal. In this case, the servo motor can be continuously controlled by switching from the encoder measured value to the first estimated measured value. If the input ambient environment data does not correspond to the guarantable environment data stored when the encoder is normal, the servomotor is stopped.

Further, in this embodiment, when storing the guarantable environment data, store calibration data for adjusting the value of the first estimated measured value, correct the first estimated measured value with this calibration data, Since the control of the servomotor is continued based on the corrected first estimated measurement value, it is possible to continue operation with higher safety. In addition, since data for performing calibration of the orientation of the visual sensor, etc., is also stored, the imaging conditions of the visual sensor itself can be stabilized.

<<Example 2>>
Next, a servo system in Example 2 of the present invention will be described with reference to the drawings. FIG. 5 is a diagram showing the configuration of the servo system of the second embodiment.

In the servo system of Example 1 (FIG. 1), the arithmetic processing section 12 and the storage section 14 are provided in the servo amplifier 10 . On the other hand, the servo system 1 of the second embodiment is different in that the arithmetic processing section 12 and the storage section 14 are provided in the host controller 50 . Other than that, the same control as in the first and second embodiments is performed.

That is, the contents of the second embodiment are almost the same as those described in the first embodiment. Therefore, redundant description of the content already described is omitted here. Specifically, the arithmetic processing unit 12 provided in the host controller 50 is functionally equivalent to the arithmetic processing unit 12 in the servo amplifier 10 of the first embodiment. Also, the contents stored in the storage unit 14 are the same as those shown in FIG. Furthermore, the operation flow in the arithmetic processing unit 12 is also the same as the contents shown in FIGS. Therefore, redundant descriptions of these matters will be omitted. Also in the second embodiment, the servo amplifier 10 and the host controller are connected so as to be able to communicate with each other. Hereinafter, the difference between the second embodiment and the first embodiment will be mainly described.

In FIG. 5, the ambient environment data KD, the image G captured by the visual sensor 30, the current I, and the measured values (motor speed and position) of the encoder 21 are taken into the arithmetic processing unit 12 provided in the host controller 50. (entered). Using these data, the arithmetic processing unit 12 calculates a first estimated measured value corresponding to the measured value (velocity/position) of the encoder 21 based on the image G, and when the encoder 21 is normal, The soundness of the data is determined based on whether or not the difference between the measured value and the first estimated measured value is within a predetermined threshold.

If the data is sound, the ambient environment data KD is stored as the guarantable environment data, and if it is determined that the encoder 21 is abnormal, the input ambient environment data is stored as the guarantable environment when the encoder is normal. If it corresponds to the data, the motor controller 11 in the servo amplifier 10 is controlled to switch from the encoder measured value to the first estimated measured value A1. That is, the arithmetic processing unit 12 outputs the switching signal C and the first estimated measurement value A1 to the motor control unit 11. FIG. Thereby, the motor control unit 11 can continue to operate the servomotor using the first estimated measurement value A1.

If the input ambient environment data KD does not correspond to the guaranteeable environment data stored when the encoder is normal, the arithmetic processing unit 12 outputs a stop command ST to the motor control unit 11 . When receiving the stop command ST, the motor control unit 11 performs control to stop the servomotor. Note that the adjustment of the first estimated measurement value and the posture control of the visual sensor based on the calibration data have already been explained, so a description thereof will be omitted.

According to the second embodiment of the present invention, it has the same effects as the first embodiment described above. In addition, in the second embodiment, when there are a plurality of servo systems composed of servo motors and servo amplifiers, it is not necessary to provide an arithmetic processing unit for each servo system, so the overall configuration is simplified.

Reference Signs List 1 Servo system 10 Servo amplifier 11 Motor control unit 12 Arithmetic processing unit 13 Current sensor 14 Storage unit 20 Servo motor 21 Encoder 50 Host controller
110...Switching unit 111...Control unit 121...ROM 122...RAM 123...Image processing unit 124...CPU 125...Setting unit 126...I/O

Claims (13)

A servo system comprising a servomotor having an encoder and a servo amplifier that feeds back a measurement value of the encoder to control the servomotor,
a visual sensor for capturing an image of a controlled object driven by the servomotor; and an ambient environment detection unit for detecting ambient environment data of the servo system,
The servo amplifier receives the image and the ambient environment data, calculates a first estimated measured value corresponding to the measured value based on the image, and calculates the measured value and the first estimated measured value during a period when the encoder is normal. The soundness of the data is determined based on whether or not the difference from one estimated measurement value is within a predetermined threshold. If it is determined to be abnormal, the input ambient environment data and the stored guarantable environment data are collated, and if the corresponding guarantable environment data exists, the first estimated measured value is calculated. A servo system using to control the servo motor. A servo system as claimed in claim 1, wherein
When recording the guarantable environment data, the servo amplifier records a difference or ratio between the first estimated measured value and the measured value together with the guarantable environment data, and drives the servo motor according to the first estimated measured value. and adjusting the first estimated measurement value using the difference or the ratio. A servo system as claimed in claim 1, wherein
When recording the guarantable environment data, the servo amplifier records the imaging conditions of the visual sensor together with the guarantable environment data, and controls the servo motor with the first estimated measurement value. A system for adjusting the visual sensor based on a condition. A servo system as claimed in claim 1, wherein
a current sensor for detecting a current supplied to the servomotor;
The servo amplifier calculates a second estimated measured value corresponding to the measured value based on the current, and when judging the soundness, the measured value, the first estimated measured value, and the second estimated measured value. are compared with each other, and if they are within the threshold value, it is determined that the soundness is present. A servo system as claimed in claim 1, wherein
The servo amplifier determines that the encoder is abnormal and compares the input ambient environment data with the stored assurable environment data. A servo system that stops a servo motor. A servo system as claimed in claim 1, wherein
The servo amplifier includes a motor control unit that controls the motor using the measured value of the encoder when the encoder is normal, an arithmetic processing unit that controls the driving of the motor control unit, and a storage unit.
The arithmetic processing unit acquires the image and the ambient environment data, calculates a first estimated measured value corresponding to the measured value based on the image, and calculates the measured value and the first estimated measured value when the encoder is normal. 1 judging whether the difference from the estimated measurement value is within a predetermined threshold value, and if the data is sound, storing the ambient environment data as guarantable environment data in the storage unit; When the encoder is determined to be abnormal and the input ambient environment data corresponds to the guarantable environment data stored in the storage unit, the first estimated measurement value is sent to the motor control unit. and the motor control unit controls the motor using the supplied first estimated measurement value. A servo system as claimed in claim 6, wherein
A servo system comprising a host controller connected to the servo amplifier so as to be able to communicate with each other, wherein the arithmetic processing section and the storage section are incorporated in the host controller. A servo system as claimed in claim 1, wherein
The servo system according to claim 1, wherein the servo amplifier is equipped with a dynamic reconstruction processor, and image processing is performed by the dynamic reconstruction processor when calculating the first estimated measurement value based on the image. A control method for a servo system comprising a servomotor equipped with an encoder and a servo amplifier that feeds back a measurement value of the encoder to control the servomotor,
An image of the controlled object driven by the servomotor is captured using a visual sensor, and ambient environment data of the servo system is captured using an ambient environment detection unit, and a first estimated measurement corresponding to the measured value is performed based on the image. Calculate the value of
During a period in which the encoder is normal, whether or not the difference between the measured value and the first estimated measured value is within a predetermined threshold determines the soundness of the data, and if soundness is present, the surrounding storing environmental data as certifiable environmental data;
When it is determined that the encoder is abnormal, the input ambient environment data and the guarantable environment data are collated, and if the corresponding guarantable environment data exists, the first estimated measurement A method of controlling a servo system, wherein a value is used to control the servo motor. In the servo system control method according to claim 9,
When recording the guarantable environment data, the servo amplifier records a difference or ratio between the first estimated measured value and the measured value together with the guarantable environment data, and drives the servo motor according to the first estimated measured value. and adjusting the first estimated measurement value using the difference or the ratio when controlling the driving of the system. In the servo system control method according to claim 9,
When recording the certifiable environment data, the imaging conditions of the visual sensor are recorded together with the certifiable environment data, and when the servo motor is controlled by the first estimated measurement value, the visual sensor is controlled based on the imaging conditions. A method of controlling a servo system, comprising adjusting a sensor. In the servo system control method according to claim 9,
calculating a second estimated measured value based on the current supplied to the servo motor;
When judging the soundness, the mutual deviation between the second estimated measured value based on the current, the first estimated measured value based on the visual sensor, and the measured value by the encoder is within the threshold. A control method for a servo system, characterized in that the presence of soundness is determined by: In the servo system control method according to claim 9,
When it is determined that the encoder is abnormal, and the input ambient environment data and the stored guarantable environment data are collated, and if the corresponding guarantable environment data does not exist, the servomotor is stopped. A servo system control method characterized by:

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