JP2016001430A - Position control device and position control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve high responsibility and stability even when it takes a long time due to the occurrence of an overshoot until an operation object transits from a transient state to a steady state.SOLUTION: A target position command signal generation circuit 26 generates a target position command signal VTARG of a mobile body 33. A PID control circuit 25 inputs an output signal VPROC and target position command signal VTARG of a magnetic sensor 21, and generates an operation amount signal MV of the mobile body. A PID control circuit 25 includes: a proportional arithmetic part 42 for outputting a proportional value which is proportional to a first difference E between the output signal VPROC and the target position command signal VTARG; an integration arithmetic part 43 for outputting an integrated value which is proportional to the time integration of the first difference E; a differential arithmetic part 41 for outputting a differential value which is proportional to the time differential of the output signal VPROC; and a feedback part 48 for feeding back the operation amount signal MV to the input side of the integration arithmetic part 43. Especially, this invention is suitable for the auto-focusing of a lens.

Description

  The present invention relates to a position control device and a position control method. More specifically, the present invention relates to a position control device that suppresses overshoot until an operation target changes from a transient state to a steady state, thereby enabling high responsiveness and stability. And a position control method.

  Many of the camera modules installed in smart phones, which are multifunctional mobile phones that have high compatibility with general digital cameras, mobile phones, and the Internet and are based on the functions of personal computers, (AF) function is installed. A contrast detection method is often adopted for an autofocus function mounted on such a compact camera. In this contrast detection method, the lens is actually moved to detect the lens position where the contrast of the subject in the captured image is maximized, and the lens is moved to that position.

  Such a contrast detection method can be realized at a lower cost compared to an active method in which the subject is irradiated with infrared rays or ultrasonic waves and the distance from the reflected wave to the subject is measured. However, there is a problem that it takes time to search for a lens position where the contrast of the subject is maximized. It is desired that the process from when the user presses the shutter button halfway until the subject is focused is completed in a short time (for example, within one second).

By the way, the number of pixels of camera modules mounted on general digital cameras and mobile phones is increasing year by year, and high-definition images can be taken even with these compact cameras. In high-definition images, since the focus shift becomes conspicuous, more accurate autofocus control is required.
In general, a device in which an input signal and a displacement corresponding to the input signal are represented by a linear function is called a linear motion device. An example of this type of linear motion device is a camera autofocus lens.

FIG. 1 is a configuration diagram for explaining a conventional linear motion device control apparatus. In the figure, reference numeral 1 is a magnetic sensor, 2 is an A / D conversion circuit, 3 is a PID control circuit, 4 is a device position command signal generation circuit, 5 is a D / A conversion circuit, 6 is an output driver, 7 is a drive coil, 8 Indicates a moving object.
The magnetic sensor 1 detects a magnetic field generated by a magnet (not shown) attached to the moving body 8 and outputs a detected position signal value Vip corresponding to the detected magnetic field value. The magnetic sensor 1 is preferably a Hall element.

The A / D conversion circuit 2 amplifies the detection position signal from the magnetic sensor 1 and performs A / D conversion, and obtains a detection position signal value Vip subjected to A / D conversion. The device position command signal generation circuit 4 outputs a target position signal value indicating a target position where the moving body 8 should be moved and a calibration execution signal, and is connected to the PID control circuit 3.
The PID control circuit 3 outputs a control signal for moving the moving body 8 to the target position from the target position of the moving body 8 indicated by the current position of the moving body 8 and the target correction position signal value. To do. The output signal from the PID control circuit 3 is D / A converted by the D / A conversion circuit 5, and a drive current is supplied to the drive coil 7 by the output driver 6.
A conventional linear motion device control apparatus as described above is disclosed in, for example, Patent Document 1.

  FIG. 2 is a specific configuration diagram of the controller for the conventional linear motion device in FIG. In FIG. 2, a case where the present invention is applied to the control device 20 that adjusts the position of the lens (moving body) 33 of the camera module 30 will be described. The control device (position control circuit) 20 is configured as an IC circuit, for example. The camera module 30 includes a linear motion device 31 and a drive coil 29 that moves the lens 33. Therefore, by passing a current through the drive coil 29, the magnet 32 is moved, and the position of the lens 33 fixed to the magnet 32 can be adjusted.

That is, the controller 20 of the linear motion device 31 shown in FIG. 2 is arranged in the vicinity of the linear motion device 31 having the magnet 32 attached to the lens (moving body) 33 and the magnet 32 of the linear motion device 31. The drive coil 29 is provided, and the magnet 32 is moved by a force generated by a coil current flowing through the drive coil 29.
The control device 20 of the linear motion device 31 shown in FIG. 2 is provided with a measure for preventing the magnetic sensor 21 from being affected by the leakage magnetic field of the drive coil 29 and causing a detection error. . The calibration calculation circuit 24 has a time to stop energization of the drive coil 29 immediately before obtaining the detected magnetic field, and based on the detected position signal value Vip A / D converted by the A / D conversion circuit 23, The detected position calculation signal value VPROC is obtained from the first position signal value NEGCAL corresponding to the home position of the linear motion device 31 and the second position signal value POSCAL corresponding to the full position of the linear motion device 31.

The leakage magnetic field correction circuit 34 is connected to the device position command signal generation circuit 26 and the calibration calculation circuit 24, and corrects the detection error of the magnetic sensor 21 due to the leakage magnetic field of the drive coil 29.
In FIG. 2, the PID control circuit 25 is connected to the calibration calculation circuit 24 and the leakage magnetic field correction circuit 34, and the detected position calculation signal value VPROC from the calibration calculation circuit 24 and the target correction position signal from the leakage magnetic field correction circuit 34. A value VTARG ′ is input, and control for moving the lens 33 to the target position from the current position of the lens (moving body) 33 and the target position of the lens 33 indicated by the target correction position signal value VTARG ′. A signal is output.

  PID control is a kind of feedback control, and is a method of performing control of an input value by three elements of a deviation between an output value and a target value, its integration and differentiation. There is proportional control (P control) as basic feedback control. This controls the input value as a linear function of the deviation between the output value and the target value. In PID control, an operation for changing an input value in proportion to this deviation is referred to as a proportional operation or a P operation (P is an abbreviation for PROPORIONAL). In other words, if a state with a deviation continues for a long time, the change of the input value is increased and the role of trying to approach the target value is achieved. The operation of changing the input value in proportion to the integration of the deviation is referred to as an integration operation or an I operation (I is an abbreviation for INTERGRAL). A control method combining the proportional action and the integral action in this way is called PI control. The operation of changing the input value in proportion to the differential of the deviation is referred to as differential operation or D operation (D is an abbreviation for DERIVATIVE or DIFFERENTIAL). A control method combining such proportional operation, integral operation and differential operation is called PID control.

  FIGS. 3A to 3C are block diagrams showing various conventional PID control circuits. FIG. 3A is a classic PID control circuit, and FIG. 3B is a differential leading type. FIG. 3C is a block diagram of a PID control circuit of a proportional differential preceding type. In the figure, reference numeral 41 is a differential calculation unit (incomplete differentiation), 42 is a proportional calculation unit, 43 is an integral calculation unit, 44 is a gain amplification unit, 45 is a first deviation calculation unit, and 46 is a control output calculation unit. Yes. Note that these PID control circuits are disclosed in, for example, Patent Document 2 and Patent Document 3.

International Publication No. 2013/171998 JP 2004-227432 A JP-A-6-168003

However, in the position control device using the conventional PID control circuit, when the target value of the operation target changes significantly, the operation amount increases rapidly. For this reason, there is a problem in that overshoot occurs until the operation target (for example, the lens position) transitions from the transient state to the steady state, and it takes time to transition from the transient state to the steady state.
The present invention has been made in view of such problems, and the object of the present invention is to suppress overshoot that occurs until the operation target transitions from a transient state to a steady state with a small circuit area, and has high responsiveness. It is another object of the present invention to provide a position control device and a position control method that enable stability.

  The present invention has been made to achieve such an object. The invention according to claim 1 detects the position of the moving body (33) including the magnet (32) by the magnetic sensor (21). A target position command signal generation circuit (26) for generating a target position command signal (VTARG) of the moving body (33) in a position control device that drives the moving body (33) to a target position based on an operation amount. And a position signal (VPROC) and a target position command signal (VTARG) detected by the magnetic sensor (21) as inputs, and a PID that generates an operation amount signal (MV) of the moving body (33) A control circuit (25), wherein the PID control circuit (25) includes a proportional operation unit (42) that performs a proportional operation, an integration operation unit (43) that performs an integral operation, and a differential operation unit that performs a differential operation. (41) and before A feedback unit (48) that feeds back an operation amount signal (MV) to the integration calculation unit (43), and the PID control circuit (25) is configured to output a first of the target position command signal and the position signal. The integration operation unit (43) integrates a second difference (F) that is a difference between the difference (E) between the output signal and the output signal of the feedback unit. (Example 1; FIGS. 2 and 5)

According to a second aspect of the present invention, in the first aspect of the invention, the PID control circuit (25) determines the feedback amount of the feedback unit (48) according to the first difference (E). It is characterized by adjusting. (Example 2; FIG. 9)
According to a third aspect of the present invention, in the second aspect of the present invention, the PID control circuit (25) includes an absolute value calculation unit (50) for calculating an absolute value of the first difference (E). And the feedback amount of the feedback section (48) is adjusted according to the absolute value. (Example 2; FIG. 7)
According to a fourth aspect of the present invention, in the third aspect of the present invention, the PID control circuit (25) is configured to multiply the absolute value and the output signal of the feedback unit (48) by a multiplier (49). The feedback amount is adjusted by multiplying by. (Example 2; FIG. 7)

The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the PID control circuit (25) includes a low-pass filter circuit (51) and a target value filter circuit (52). PID control is performed on the position signal that has passed through the low-pass filter circuit and the target position command signal that has passed through the target value filter circuit. (Example 6; FIG. 12)
According to a sixth aspect of the present invention, in the fifth aspect of the invention, the absolute value calculation unit passes through the target position command signal before passing through the target value filter circuit and a low pass filter circuit. An absolute value of a difference from the position signal is calculated.

The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the PID control circuit (25) includes the proportional calculation unit (42) and the integral calculation unit (43). ), And a gain amplifying unit for gain-amplifying a signal obtained by adding or subtracting the output signal from the differentiation operation unit (41) for performing the differentiation operation and outputting it as an operation amount signal. (Example 1; FIGS. 2 and 5)
The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the proportional calculation unit performs a proportional operation of the first difference (E), or A proportional operation of the position signal is performed, and the differential operation unit performs a differential operation of the first difference (E) or performs a differential operation of the position signal.
The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the moving body is a linear motion device of an autofocus lens.

In the invention according to claim 10, the position of the moving body (33) including the magnet (32) is detected by the magnetic sensor (21), and the moving body (33) is detected based on the operation amount. In the position control method for driving the moving body, a target position command signal generating step for generating a target position command signal (VTARG) of the moving body (33), and a position signal (VPROC) of the moving body detected by the magnetic sensor (21). ) And a PID control step of generating an operation amount signal (MV) based on the target position command signal (VTARG) and performing PID control, the PID control step differentiating the position signal; A step of calculating a first difference between a position signal (VPROC) and the target position command signal (VTARG), and a step of calculating a proportional value proportional to the first difference (E). Generating a feedback signal from the manipulated variable signal, subtracting the feedback signal from the first difference (E), calculating a second difference, and integrating the second difference And a step.
The invention according to claim 11 is the invention according to claim 10, wherein the PID control step calculates an absolute value of the first difference (E), the absolute value and the feedback signal. And the step of integrating the second difference is a step of integrating a signal obtained by multiplying the absolute value and the feedback signal.

  According to the present invention, a position control device and a position control method that suppress overshoot that occurs until an operation target transitions from a transient state to a steady state with a small circuit area and enables high responsiveness and stability are realized. be able to.

It is a block diagram for demonstrating the control apparatus of the conventional linear motion device. It is a specific block diagram of the control apparatus of the conventional linear motion device in FIG. (A) thru | or (c) are block diagrams which show various conventional PID control circuits. (A) thru | or (c) is a figure for demonstrating the further improvement point of the PID control circuit in FIG. It is a circuit block diagram for demonstrating Example 1 of the position control apparatus which concerns on this invention. (A) thru | or (c) is a figure for demonstrating the effect in Example 1 shown in FIG. It is a circuit block diagram for demonstrating Example 2 of the position control apparatus which concerns on this invention. It is a circuit block diagram for demonstrating Example 3 of the position control apparatus which concerns on this invention. It is a circuit block diagram for demonstrating Example 4 of the position control apparatus which concerns on this invention. (A) thru | or (c) is a figure for demonstrating the effect in Example 2 thru | or 4 shown in FIG. 7 thru | or FIG. It is a circuit block diagram for demonstrating Example 5 of the position control apparatus which concerns on this invention. It is a circuit block diagram for demonstrating Example 6 of the position control apparatus which concerns on this invention. (A), (b) is a figure for demonstrating the characteristic structure in Example 6 shown in FIG. It is a circuit block diagram for demonstrating Example 7 of the position control apparatus which concerns on this invention.

First, a PID control circuit which is a premise of the present invention will be described with reference to FIG. The PID control circuit 25 shown in FIG. 3B corresponds to the PID control circuit 25 in FIG. 2, and the input signal Vip (VPROC) and the target value VTARG also correspond to the signals shown in FIG.
PID control calculates a control output (operation amount) MV based on a deviation (difference) E between an input signal VPROC to be controlled and a target value VTARG, thereby bringing the input signal VPROC closer to the target value VTARG and close to the target value. It is possible to hold on the value.

  In the PID control, a proportional operation (P operation) for outputting a proportional value proportional to the deviation E by the proportional calculation unit 42 and an integration operation for outputting an integral value proportional to the time integration of the deviation E by the integral calculation unit 43 (P operation). The control is performed by combining three operations: an I operation) and a differential operation (D operation) that outputs a differential value proportional to the time differentiation of the input signal VPROC by the differential operation unit 41. Each of these operations has parameters, and various devices having different dynamic characteristics can be controlled by selecting appropriate parameters.

The deviation calculator 45 is for calculating a deviation E between the target value VTARG and the input signal VPROC from the magnetic sensor (corresponding to reference numeral 21 in FIG. 2).
The proportional calculation unit 42 is for outputting a proportional value KP proportional to the deviation E output from the deviation calculation unit 45, and corresponds to the P operation in the conventional PID control.
The integral calculation unit 43 is for outputting an integral value KI proportional to the time integral of the deviation E output from the deviation calculation unit 45, and corresponds to the I operation in the conventional PID control.

The differential operation unit 41 is for outputting a differential value KD proportional to the time differential of the input signal VPROC from the magnetic sensor, and corresponds to the D operation in the conventional PID control.
The control output calculation unit 46 is for calculating a control output value (operation amount) MV via the gain amplifier 44 based on outputs from the proportional calculation unit 42, the integral calculation unit 43, and the differentiation calculation unit 41. is there. Specifically, the control output calculation unit 46 calculates the sum of the proportional value KP, the integral value KI, and the differential value KD output from the proportional calculation unit 42, the integral calculation unit 43, and the differential calculation unit 41 ( Add or subtract) and output to the controlled object.

4A to 4C are diagrams for explaining further improvements of the PID control circuit in FIG. 3, in which FIG. 4A is a target value, FIG. 4B is an operation amount, and FIG. (C) shows the operation target (lens position).
As shown in FIG. 4A, when the target value changes significantly, the operation amount increases rapidly as shown in FIG. 4B. As a result, as shown in FIG. 4C, overshoot occurs until the operation target (lens position) transitions from the transient state to the steady state, resulting in poor stability. In addition, there is a problem that it takes time until the transition from the transient state to the steady state, and the responsiveness is poor.
Hereinafter, embodiments for solving such problems will be described.

FIG. 5 is a circuit configuration diagram for explaining Example 1 of the position control device according to the present invention. In the figure, reference numeral 47 indicates a feedback calculation unit, and 48 indicates a feedback unit. In addition, the same code | symbol is attached | subjected to the component which has the same function as FIG.3 (b).
As shown in FIG. 1 or FIG. 2, the position control apparatus of the first embodiment detects the position of the moving body 33 including the magnet 32 (FIG. 2) by the magnetic sensor 21, and sets the moving body 33 to the target value. It is a position control device that drives to a target position based on it.

  The position control apparatus according to the first embodiment includes, for example, an A / D conversion circuit that AD-converts an output signal from a magnetic sensor that detects the position of a moving body, an output of the A / D conversion circuit, and a device position command signal generation circuit. A PID control circuit that performs PID control based on the output, a target position command signal generation circuit (device position command signal generation circuit) that generates a target position command signal, and D / D that outputs the output of the PID control circuit to the output driver after D / A conversion A conversion circuit is included. The output driver drives the drive coil in accordance with the operation amount signal of the PID control circuit to drive the position of the moving body.

The magnetic sensor detects a magnetic field generated by a magnet attached to the moving body and outputs a detected position signal value Vip corresponding to the detected magnetic field value. The magnetic sensor is preferably a Hall element.
The A / D conversion circuit amplifies the detection position signal from the magnetic sensor and performs A / D conversion, and obtains a detection position signal value Vip subjected to A / D conversion.

The target position command signal generation circuit outputs a target position signal value indicating a target position where the moving body is to be moved and a calibration execution signal to the PID control circuit.
A target position command signal generation circuit (device position command signal generation circuit) 26 generates a target position command signal VTARG for the moving body 33. The PID control circuit 25 receives the output signal (input signal of the PID control circuit 25) VPROC and the target position command signal VTARG of the magnetic sensor 21, and generates an operation amount signal MV of the moving body 33.

  Further, the PID control circuit 25 performs a proportional operation for outputting a proportional value proportional to the first deviation (difference) E between the output signal VPROC of the magnetic sensor 21 and the target position command signal VTARG by the first deviation calculator 45. A proportional calculation unit 42 for performing an integration operation for outputting an integral value proportional to the time integral of the first deviation E, and a differential operation for outputting a differential value proportional to the time differentiation of the output signal VPROC. A differential calculation unit 41 to perform, and a feedback unit 48 that feeds back the manipulated variable signal MV to the input side of the integration calculation unit 43 are provided.

In the feedback unit 48, the operation amount signal MV is most simply multiplied by a scaling coefficient. However, the operation amount signal MV may be appropriately filtered, modulated, or operated.
Further, the integration calculation unit 43 integrates the second deviation (difference) F by the feedback calculation unit 47 between the first deviation E and the output signal of the feedback unit 48. The moving body 33 can be a linear motion device of an autofocus lens.
In other words, the feedback calculation unit 47 is provided in front of the integration calculation unit 43, and the control output value (operation amount) MV from the gain amplifier 44 is fed back to the input of the integration calculation unit 43 via the feedback unit 48, so that the target The controllability of the PID control circuit is improved in the transitional interval when the value changes. As a result, stability is improved and response is also improved.

  FIGS. 6A to 6C are diagrams for explaining the effects of the first embodiment shown in FIG. 5. FIG. 6A is a target value, FIG. 6B is an operation amount, and FIG. c) shows the operation target (lens position). As is clear from FIG. 6C, overshoot is improved before the operation target (lens position) transitions from the transient state to the steady state as compared with FIG. 4C, and the transition from the transient state to the steady state is performed. Time is shortened, and responsiveness is improved in a transient state. In addition, since the internal configuration of the PID control circuit, the circuit can be miniaturized.

  In addition to the form in which the manipulated variable signal is fed back to the integral calculation unit, a form in which the operation amount signal is fed back to the proportional calculation unit, the differential calculation unit, and both may be employed. Further, the feedback of the manipulated variable signal may be a form in which feedback of the output signal of the feedback unit, feedback of the output of the feedback unit and the multiplication result of the absolute value calculation unit, and a signal according to them are fed back.

FIG. 7 is a circuit configuration diagram for explaining a second embodiment of the position control device according to the present invention. In the figure, reference numeral 49 denotes a multiplication unit, and 50 denotes an absolute value calculation unit. In addition, the same code | symbol is attached | subjected to the component which has the same function as FIG. An example in which the present invention is applied to the differential leading type PID control circuit shown in FIG.
The PID control circuit 25 in the position control apparatus according to the second embodiment is configured such that the feedback amount of the feedback unit 48 is adjusted according to the first deviation E. The PID control circuit 25 also includes an absolute value calculation unit 50 that calculates the absolute value of the first deviation E so that the feedback amount of the feedback unit 48 is adjusted according to the absolute value of the first deviation E. It is configured. The PID control circuit 25 is configured such that the feedback amount is adjusted by multiplying the absolute value of the first deviation E and the output signal of the feedback unit 48 by a multiplier 49.
That is, by providing the multiplication unit 49 between the feedback calculation unit 47 and the feedback unit 48 and providing the absolute value calculation unit 50 between the output side of the deviation calculation unit 45 and the multiplication unit 49, The deviation amount and the feedback amount are calculated so that the target value error is eliminated.

Although the controllability of the PID control circuit is improved in the transient state when the target value changes due to the feedback of the operation amount MV, the operation amount MV_Bias is necessary to stabilize the operation target in the steady state. If this MV_Bias is present, an offset remains in the integral calculation input and a target value shift occurs. However, in the second embodiment, in the steady state, the deviation E between the target value VTARG and the input signal VPROC is almost 0, so the feedback amount of the operation amount signal MV is 0. Therefore, the controllability of the PID control circuit can be improved in the transitional section when the target value changes due to the feedback of the operation amount MV, and the target value deviation does not occur.
The second embodiment is a form in which the absolute value of the deviation E is multiplied by the output of the feedback unit 48, but is not the absolute value of the deviation E but a signal that converges from 0 to 0 in a certain time, and is controlled. Any configuration can be used as long as the feedback amount of the manipulated variable signal in the PID control circuit can be zero in a steady state, such as a form in which the output of the feedback unit 48 is multiplied by a signal that enhances the performance.

FIG. 8 is a circuit configuration diagram for explaining Example 3 of the position control device according to the present invention. In addition, the same code | symbol is attached | subjected to the component which has the same function as FIG. An example in which the present invention is applied to the classical PID control circuit shown in FIG.
That is, the differential calculation unit 41 does not directly calculate the input signal VPROC but calculates a deviation E from the point A.

FIG. 9 is a circuit configuration diagram for explaining Example 4 of the position control device according to the present invention. In addition, the same code | symbol is attached | subjected to the component which has the same function as FIG. An example is shown in which the present invention is applied to the proportional-differential-preceding type PID control circuit shown in FIG.
That is, the proportional calculation unit 42 does not calculate the deviation E from the point A, but directly calculates the input signal VPROC.

FIGS. 10A to 10C are diagrams for explaining the effects in the second to fourth embodiments shown in FIGS. 7 to 9, where FIG. 10A is a target value, and FIG. 10B is an operation. FIG. 10C shows the operation target (lens position).
Here, in the case of multiplying the output of the feedback unit 48 using the deviation E, the absolute value calculation unit 50 is required. In the following, it is assumed that there is no absolute value calculation unit 50 and the deviation E is input to the multiplier 49 with the same sign.
When the lens moving direction is the positive direction, the deviation E is a positive value, and the operation amount signal MV is also a positive value. Therefore, the output signal of the multiplier 49 becomes a positive value, and the deviation F obtained by calculating the difference of the output (positive value) of the multiplier 49 with respect to the deviation E (positive value) is input to the integral calculation unit 43. The peak value of the operation amount can be reduced.

On the other hand, when the lens moving direction is a negative direction, the deviation E is a negative value, and the operation amount signal MV is also a negative value. Therefore, the output signal of the multiplier 49 becomes a positive value, and when the deviation F obtained by calculating the difference of the output (positive value) of the multiplier 49 with respect to the deviation E (negative value) is input to the integral calculation unit 43, In addition, the peak value of the operation amount becomes large.
Therefore, in order to reduce the peak value of the manipulated variable regardless of whether the lens movement direction is positive or negative and suppress the target value deviation, the absolute value calculation unit 50 is required. When the lens moving direction is a negative direction, the deviation E is a negative value, and the operation amount signal MV is also a negative value. However, since the absolute value calculation unit 50 is provided, the output signal of the multiplier 49 becomes a negative value, and the deviation F obtained by calculating the difference of the output (negative value) of the multiplier 49 with respect to the deviation E (negative value) is an integral calculation. By inputting to the unit 43, the peak value of the operation amount can be reduced.

FIG. 11 is a circuit configuration diagram for explaining a fifth embodiment of the position control apparatus according to the present invention. In addition, the same code | symbol is attached | subjected to the component which has the same function as FIG.
The position control device of the fifth embodiment is a modification of the position control device of the second embodiment described above. In the second embodiment, the proportional calculation unit 42 receives the deviation E of the first deviation calculation unit 45 as an input. However, in the fifth embodiment, the input signal VPROC is directly input. That is, the proportional calculation unit 42 is configured to perform a proportional operation that outputs a proportional value that is proportional to the output signal VPROC of the magnetic sensor 21 instead of performing a proportional operation that outputs a proportional value that is proportional to the first deviation E. Has been. In such a connection relationship, the same effects as those of the second embodiment are obtained.

FIG. 12 is a circuit configuration diagram for explaining a sixth embodiment of the position control apparatus according to the present invention. In the figure, reference numeral 51 denotes a low-pass filter (LPF; primary) circuit, 52 denotes a target value filter circuit, and 53 denotes a second deviation calculator. In addition, the same code | symbol is attached | subjected to the component which has the same function as FIG.
The position control apparatus according to the sixth embodiment is a further modification of the position control apparatus according to the second embodiment described above, and includes an LPF circuit 51 in the preceding stage of the differential calculation section 41 and the first deviation calculation section 45. A target value filter circuit 52 is provided in the preceding stage, and the absolute value calculation unit 50 receives the third deviation (difference) G between the target value VTARG and the output signal of the LPF circuit 51 via the second deviation calculation unit 53. Yes.
That is, the PID control circuit 25 in the position control apparatus of the sixth embodiment is provided with the LPF circuit 51 in the previous stage of the differential calculation unit 41 and the target value filter circuit 52 in the previous stage of the first deviation calculation unit 45. A second deviation calculation unit 53 is provided in the preceding stage of the value calculation unit 50.

  Since the target value filter circuit 52 is provided, the configuration of the PID control circuit can be switched in a stepwise manner from the proportional differential preceding type PID control to the differential leading type PID control. The target value filter circuit 52 is a filter circuit mainly having a phase advance / lag compensation element. The parameters of the target value filter circuit 52 include a first parameter such that the time constant τ1 of the phase lag element becomes a time constant proportional to the integration time in the integration calculation unit 43 of the PID control circuit 25, and the time of the phase advance element. A second parameter is set such that the constant τ2 becomes a time constant proportional to the time constant τ1 of the phase delay element. However, any configuration may be used as long as the configuration is such as a filter and a calculation that can arbitrarily adjust the generated waveform of the target value VTARG.

FIGS. 13A and 13B are diagrams for explaining a characteristic configuration in the sixth embodiment shown in FIG. 12, and FIG. 13A is an input signal of the target value filter, and FIG. Indicates the output signal of the target value filter.
In the second embodiment shown in FIG. 7, the deviation E is input from the intermediate point A between the first deviation calculating section 45 and the feedback calculating section 47 to the absolute value calculating section 50. In the sixth embodiment, The difference between the signal before the input of the target value filter circuit 52 and the output signal of the LPF circuit 51 is inputted as the third deviation G via the second deviation calculator 53.

  The input signal and output signal of the target value filter circuit 52 have waveforms as shown in FIGS. 13A and 13B depending on the setting parameters. By calculating the difference between the signal before the input of the target value filter circuit 52 and the output signal of the LPF circuit 51 instead of the output signal of the target value filter circuit 52, a feedback calculation of the manipulated variable MV according to the setting parameters of the target value filter circuit 52 The deviation used in the above does not fluctuate and becomes a large deviation immediately after the target value is changed. Thereby, target value shift | offset | difference can be suppressed with sufficient precision. Note that a PID control circuit configuration different from the method described in this embodiment may be used.

FIG. 14 is a circuit configuration diagram for explaining a seventh embodiment of the position control apparatus according to the present invention. Components having the same functions as those in FIG. 12 are denoted by the same reference numerals.
The position control device of the seventh embodiment is a modification of the position control device of the sixth embodiment described above. In the sixth embodiment, the multiplication unit 49 is provided between the feedback calculation unit 47 and the feedback unit 48. This is removed, and the output signal of the absolute value calculation unit 50 is directly input to the feedback unit 48.

That is, the output of the absolute value calculation unit 50 is input to the feedback unit 48 instead of being input to the multiplier 49, and the FB (feedback) amount is directly adjusted. However, the following must be satisfied.
1) Feed back the operation amount MV, 2) The feedback amount is output in the transient state, and the feedback amount is zero or almost zero in the steady state. 3) The signal input to the feedback calculation unit 47 is the operation amount. This is a code opposite to the code of MV.

As described above, the position control device according to the present invention includes a linear motion device control device configured so that the moving body moves linearly, a touch correction control device configured such that the mobile body moves in a plane, and the like. Is mentioned. In particular, autofocus control of a smartphone camera lens is a suitable example.
In particular, in the auto focus control, when the lens position is stabilized after the lens position is largely driven to the target position, the configuration of the second embodiment is preferable. According to this, in addition to the operability of moving the lens significantly, the stability of holding the lens stably is also improved.

The position control method of the present invention will be described below.
The position control method of the present invention is a position control method in which the position of the moving body 33 including the magnet 32 is detected by the magnetic sensor 21 and the moving body 33 is driven to the target position based on the operation amount.
Based on the target position command signal generation step for generating the target position command signal VTARG of the moving body 33, the position signal VPROC of the moving body detected by the magnetic sensor 21 and the target position command signal VTARG, the operation amount signal MV is generated and PID is generated. PID control step for controlling.

  The PID control step for generating the operation amount signal MV of the moving body 33 includes the step of differentiating the position signal, the step of calculating the first difference between the position signal VPROC and the target position command signal VTARG, Calculating a proportional value proportional to the difference E; generating a feedback signal from the manipulated variable signal; calculating a second difference by subtracting the feedback signal from the first difference E; Integrating the difference.

The PID control step for generating the operation amount signal MV of the moving body 33 is the simplest of multiplying the step of calculating the absolute value of the first difference E and the operation amount MV of the feedback unit 48 by a scaling factor. Or a step of multiplying the absolute value by the feedback signal or satisfying 1), 2), and 3) described above by an appropriate filter, modulation, or calculation for the manipulated variable MV. The step of integrating the second difference is a step of integrating a signal obtained by multiplying the absolute value and the feedback signal.
In this way, it is possible to realize a position control method that suppresses overshoot that occurs before the operation target transitions from the transient state to the steady state and enables high responsiveness and stability. Further, this configuration is very simple and can be realized with a small circuit area.

DESCRIPTION OF SYMBOLS 1 Magnetic sensor 2 A / D conversion circuit 3 PID control circuit 4 Device position (target position) command signal generation circuit 5 D / A conversion circuit 6 Output driver 7 Drive coil 8 Moving body 13 PID control device 20 Control device (position control circuit) )
21 Magnetic Sensor 22 Amplifier 23 A / D Conversion Circuit 24 Calibration Operation Circuit 25 PID Control Circuit 26 Target Position Command Signal Generation Circuits 28a and 28b Output Driver 29 Drive Coil 30 Camera Module 31 Linear Motion Device 32 Magnet 33 Lens (Moving Object)
34 Leakage magnetic field correction circuit 41 Differential calculation unit 42 Proportional calculation unit 43 Integration calculation unit 44 Gain amplification unit 45 First deviation calculation unit 46 Control output calculation unit 47 Feedback calculation unit 48 Feedback unit 49 Multiplication unit 50 Absolute value calculation unit 51 LPF Circuit 52 Target value filter circuit 53 Second deviation calculation unit

Claims (11)

In a position control device that detects a position of a moving body including a magnet by a magnetic sensor and drives the moving body to a target position based on an operation amount.
A target position command signal generation circuit for generating a target position command signal of the moving body;
A PID control circuit that receives the position signal of the moving body detected by the magnetic sensor and the target position command signal and generates an operation amount signal of the moving body, and
The PID control circuit includes a proportional operation unit that performs a proportional operation, an integration operation unit that performs an integration operation, a differential operation unit that performs a differentiation operation, and a feedback unit that feeds back the operation amount signal.
The PID control circuit is configured such that the integration calculation unit integrates a second difference which is a difference between a first difference between the target position command signal and the position signal and an output signal of the feedback unit. Position control device.   The position control device according to claim 1, wherein the PID control circuit adjusts a feedback amount of the feedback unit according to the first difference.   The position control device according to claim 2, wherein the PID control circuit includes an absolute value calculation unit that calculates an absolute value of the first difference, and adjusts the feedback amount of the feedback unit according to the absolute value. .   The position control device according to claim 3, wherein the PID control circuit adjusts the feedback amount by multiplying the absolute value and an output signal of the feedback unit by a multiplier.   The PID control circuit includes a low-pass filter circuit and a target value filter circuit, and performs PID control on the position signal that has passed through the low-pass filter circuit and the target position command signal that has passed through the target value filter circuit. The position control device according to claim 1, wherein the position control device is performed.   6. The position control according to claim 5, wherein the absolute value calculation unit calculates an absolute value of a difference between the target position command signal before passing through the target value filter circuit and the position signal via a low-pass filter circuit. apparatus.   2. The PID control circuit further includes a gain amplifying unit that amplifies a signal obtained by adding or subtracting output signals from the proportional operation unit, the integration operation unit, and the differentiation operation unit and outputs the result as an operation amount signal. The position control apparatus as described in any one of -6. The proportional calculation unit performs a proportional operation of the first difference, or performs a proportional operation of the position signal,
The position control device according to any one of claims 1 to 7, wherein the differential operation unit performs a differential operation of the first difference or performs a differential operation of the position signal.   The position control apparatus according to claim 1, wherein the moving body is a linear motion device of an autofocus lens. In a position control method for detecting a position of a moving body including a magnet by a magnetic sensor and driving the moving body to a target position based on an operation amount,
A target position command signal generating step for generating a target position command signal of the moving body;
A PID control step of generating an operation amount signal based on the position signal of the moving body detected by the magnetic sensor and the target position command signal and performing PID control,
The PID control step includes
Differentiating the position signal;
Calculating a first difference between the position signal and the target position command signal;
Calculating a proportional value proportional to the first difference;
Generating a feedback signal from the manipulated variable signal;
Subtracting the feedback signal from the first difference to calculate a second difference;
Integrating the second difference. A position control method comprising: The PID control step includes calculating an absolute value of the first difference, and multiplying the absolute value by the feedback signal;
The position control method according to claim 10, wherein the step of integrating the second difference is a step of integrating a signal obtained by multiplying the absolute value and the feedback signal.

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