JP3533318B2 - Positioning control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention is supported by a spring,
A positioning control device that controls the positioning of an actuator that moves vertically according to a drive signal from a driver,
Particularly, it relates to improvement of transient response.

[0002]

2. Description of the Related Art A positioning control device for controlling the position of an actuator by switching between speed control and position control for an actuator which is supported by a spring and has a poor damping characteristic is controlled by speed. When switching between the controller to perform and the controller to perform position control, it took time for the integral term of the switched controller to suppress the spring force. Further, when the gain of the integral term is high, it easily oscillates, and it took time to converge. Therefore, it has been desired to increase the response speed when switching between the speed-based control and the position-based control so as to quickly converge to the target value after the switching.

On the other hand, for example, in the positioning control method and the positioning control device disclosed in Japanese Unexamined Patent Publication No. 5-165527, when the control is switched, the gain of the integral guarantee means is changed. The responsiveness of is improved. Further, in the servo control device disclosed in Japanese Unexamined Patent Publication No. 8-137551, transient response is improved by applying an initial input guarantee signal of an impulse train when the controller is switched. Further, in the disk recording apparatus disclosed in Japanese Patent Laid-Open No. 8-329630, the followability during speed control is improved by feedforward.

[0004]

However, in the positioning control method and the positioning control device disclosed in Japanese Unexamined Patent Publication No. 5-165527, only the gain of the integral term is changed, so that the speed control and the position control can be performed greatly. If the control operation changes, the responsiveness cannot be sufficiently improved. Moreover, it is difficult to improve responsiveness when an optimal regulator with complicated dimensions is used as a controller.

Further, in the servo control device disclosed in Japanese Unexamined Patent Publication No. 8-137551, there is a possibility that the response may worsen if the parameters change due to changes over time.

Further, in the disk recording device disclosed in Japanese Patent Laid-Open No. 8-329630, it is impossible to improve the responsiveness when switching the controller.

The present invention has been made in order to eliminate such disadvantages, and an object thereof is to increase the response speed when switching between speed control and position control, and to quickly converge to a target value after switching.

[0008]

A positioning device according to the present invention is an actuator, a position detection unit, a speed detection unit, a target speed calculation unit, a speed control controller, a position control controller, a controller switching unit, and a controller switching command unit.
And an operation amount compensation unit and the adder and the driver, the actuator is supported by a spring, moves along the guide in response to a drive signal from the driver, the position detecting unit detects the position of the actuator, the speed detection The unit detects the moving speed of the actuator, and the target speed calculation unit calculates the target speed, which is the target of the moving speed of the actuator based on the target position of the actuator and the position of the actuator detected by the position detection unit, and the speed control controller Outputs an operation signal based on the target speed calculated by the target speed calculation unit and the moving speed of the actuator detected by the speed detection unit so that the moving speed of the actuator becomes the target moving speed. The actuator stop position is the target position based on the position and the actuator position detected by the position detector. Outputting an operation signal such that the controller switching unit speed controller has outputted Misao
The operation signal and the operation signal output from the position controller
It switches and outputs to the adder, the controller switching command section
The target position of the actuator and the position detected by the position detector
Based on the position of the actuator,
Command which output signal to output to the adder,
The calculator is the speed control controller input from the controller switching unit.
Operation signal output from the tracker or position controller
Of any of the operation signals output by the
Operation held immediately after the error switcher switches the operation signal
The operation amount correction signal input from the amount correction unit is added and output to the driver, and the actuator is positioned by a control method according to the target position and the actual position of the actuator.

The operation amount correction unit holds the added operation signal from the adder as an operation amount correction signal immediately before the controller switching unit switches the operation signal, and the driver operates the actuator according to the magnitude of the input operation signal. A drive signal is output to suppress overshoot during control switching.

Further, the operation amount correction unit inputs the operation signal output to the driver by the controller switching unit through a low-pass filter to remove the influence of noise or the like, and immediately before the controller switching unit switches the operation signal. The operation signal input via the low-pass filter is held as the operation amount correction signal.

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The positioning control device of the present invention comprises:
The position of the actuator supported by the spring is controlled by switching the control by the moving speed of the actuator and the control by the position of the actuator, and it is controlled so as to quickly stop at the target position. It improves the sex.

The positioning control device of the present invention includes an actuator, a position detection unit, a speed detection unit, a target speed calculation unit, a speed control controller, a position control controller, a controller switching unit, a controller switching command unit, and an operation amount correction unit.
It has an adder and a driver. The actuator is supported by a spring and moves in the vertical direction, for example, along the guide in response to a drive signal from the driver. The position detection unit includes, for example, an encoder and detects the position from the movement amount of the actuator. The speed detector detects the moving speed of the actuator from the cycle of the signal from the encoder, for example. The target speed calculation unit calculates a target speed that is a target of the speed at which the actuator moves by, for example, triangular drive, based on the target position of the actuator and the position of the actuator detected by the position detection unit. The speed controller outputs an operation signal so that the actual moving speed of the actuator becomes the target moving speed based on the target speed calculated by the target speed calculating unit and the moving speed of the actuator detected by the speed detecting unit. The position controller outputs an operation signal based on the target position of the actuator and the position of the actuator detected by the position detector so that the stop position of the actuator becomes the target position. The controller switching unit is the speed control
Operation signal output by controller and position controller
And outputs it to the adder by switching the operation signal output by.
The controller switching command section controls the target position of the actuator and
And the position of the actuator detected by the position detector,
Which operation signal is added to the controller switching unit
Command to output. Adder is the controller switching unit
Operation signal output from the speed controller input from
No. or operation signal output from the position controller
Some operation signal and the controller switching unit turn off the operation signal.
The operation input from the operation amount correction unit held immediately after the replacement
The amount correction signal is added and output to the driver.
In the operation amount correction unit, the controller switching unit
Input the operation signal to be output to the driver immediately before switching.
The operation signal that has been
The controller switching unit switches the operation signal output to
Direct the manipulated variable correction signal that was held immediately after
It is added to the output operation signal and output to the driver. Dora
The averaging of the current depends on the magnitude of the input operation signal.
Outputs the drive signal for the chute. In this way, by switching between speed-based control and position-based control in order to position the actuator, for example, when the target position of the actuator is separated from the target position by a predetermined value or more, the speed-based control is performed to move the actuator. By increasing the speed, the actuator quickly approaches the target position, and when the distance from the actuator to the target position becomes less than a predetermined value, control is performed according to the position, and the moving speed of the actuator is slowed to speed up the transient response. However, the position of the actuator can be quickly converged to the target position. Also, the speed control controller
Speed control by position controller and position by position controller
The response when switching the control is made faster and the transient response is improved.
You can do better and prevent overshoot when switching control
It can be kept small.

[0019]

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a positioning control device of the present invention. The positioning control device is, for example, the actuator 1.
A position detector 2, a speed detector 3, a target speed calculator 4, a speed comparator 5, a speed controller 6, a position comparator 7, a position controller 8, a controller switching command unit 9, a controller switching unit 10, and a low-pass filter. (Hereinafter "L
PF ". ) 11, an operation amount correction unit 12, and an adder 13
And driver 14.

As shown in FIG. 2, the actuator 1 includes a carriage 21 as a movable portion and a voice coil motor 24 as a driving force supply portion of the carriage 21. The carriage 21 is supported by a spring 22 for gravity compensation. In the initial state, the force of the spring 22 and the carriage 21
It stops at a position where the weights of the two are balanced. Carriage 21
Is restricted in its horizontal movement by a linear guide 23 such as an air slider, and is moved in the vertical direction by a driving force from a voice coil motor 24. The position detector 2 includes, for example, an encoder 25. The encoder 25 generates a pulse signal at a cycle according to the moving speed as the carriage 21 moves in the vertical direction. The position detector 2 detects the amount of movement of the carriage 21 based on the signal generated by the encoder 25, and detects the actual position X of the carriage 21 from the detected amount of movement of the carriage 21. The speed detector 3 calculates the actual moving speed V of the carriage 21 based on the time of the pulse interval of the pulse signal from the encoder 25.

The target speed calculation unit 4 receives the input target position Xr
Then, the target speed Vr is calculated from the actual position X of the carriage 21 detected by the position detection unit 3. For example, when the target speed is obtained by triangular drive, if the position before movement is X0, the target position is Xr, the current position of the carriage 25 is X, the acceleration of the carriage 25 is α, and the target speed is Xr, the position X0 before movement is From the intermediate point to the intermediate point {(Xr-X0) / 2}, the target speed Vr is given by the following equation.

[0023]

[Equation 1]

Further, the target velocity Vr from the intermediate point {(Xr-X0) / 2} to the target position Xr is given by the following equation.

[0025]

[Equation 2]

The speed comparator 5 includes an actual moving speed V of the carriage 21 detected by the speed detecting unit 3 and a target speed calculating unit 4
The calculated target speed Vr is compared with the target speed Vr and the speed deviation ev is output. The speed controller 6 is composed of, for example, a phase compensator, receives the speed deviation ev from the speed comparator 5, performs phase compensation such as phase delay or phase advance to ensure stability, and performs the required control. It is integrated with the comparison gain according to the performance, and the signal of the current value ic1 (n) is output as the operation signal. Here, the current value ic1 (n) indicates the current value of the operation signal output by the speed controller 6 at the n-th control timing.

The position comparator 7 compares the target position Xr with the current position X of the carriage 25 and outputs a position deviation ep. The position controller 8 is composed of, for example, a phase compensator, receives the position deviation ep from the position comparator 7, performs phase compensation such as phase delay or phase advance to ensure stability, and performs required control. It integrates with the comparison gain according to the performance, and outputs the signal of the current command value ic2 as the operation signal. Here, the current value ic2 (n) indicates the current value of the operation signal output by the position controller 9 at the n-th control timing.

When the position deviation ep output from the position comparator 7 is larger than a predetermined reference position deviation, the controller switching command unit 9 instructs the controller switching unit 10 to switch to the control by the speed control controller 6. When the position deviation ep output from the position comparator 7 is less than or equal to a predetermined reference position deviation, the controller switching unit 1 switches to control by the position controller 9.
A switching command signal is output to 0. Controller switching unit 10
Switches the signal input to the adder 13 between the operation signal from the speed control controller 6 and the operation signal from the position control controller 9 according to the command signal from the controller switching command unit 9. Here, the signal output from the controller switching unit 10 includes a current value from the speed control controller 6.
Since there is an operation signal of ic1 (n) and an operation signal of current value ic2 (n) from the position controller 9, in the following description, the current value of the operation signal output by the controller switching unit 10 will be ic (n). And

The LPF 11 extracts low frequency components from the signal from the adder 13, removes spike-like fluctuation components and noise components, and inputs the extracted low frequency components to the manipulated variable correcting unit 12. The manipulated variable correction unit 12 uses the current value IC1 of the signal input from the LPF 11 at the control timing immediately before the switching command signal from the controller switching command unit 9 is input.
(n-1) is held, and the signal of the current value IC1 (n-1) held immediately after the switching of the operation signal by the controller switching unit 10 is output to the adder 13. The adder 13 calculates the current value ic (n) of the signal from the controller switching unit 10 as shown in the following equation.
Current value IC1 (n-1) of the signal input from the manipulated variable correction unit 12
Is added and the operation signal of the current value IC1 (n) is output.

[0030]

[Equation 3]

The driver 14 outputs a drive signal for the actuator 1 having a current corresponding to the magnitude of the operation signal input from the adder 13. When the current of the signal output by the driver 14 has a positive value, the carriage 21 moves in the positive direction, and when the current of the signal output by the driver 14 has a negative value, the carriage 21 moves in the negative direction. To do.

Target position Xr is negative (gravitational acceleration direction)
In this case, when moving in the negative direction by the speed control of the speed controller 6, the spring 22 exerts a force Fk in the opposite direction to the thrust F applied to the carriage 21. The force Fk in the opposite direction to this thrust F is given by the following equation, where k is the spring constant.

[0033]

[Equation 4]

The force exerted by the spring 22 becomes a disturbance d, which causes a velocity deviation ev. This speed deviation ev is suppressed by the integral term of the speed controller 6.

When the control of the speed controller 6 is switched to the control of the position controller 9, the integral term of the switched position controller 9 is not an integral amount for suppressing the force Fk of the spring 22. Therefore, if the current value of the operation signal from the position controller 9 is not corrected,
As shown by the dotted line A in FIG. 3, the position deviation temporarily increases,
After a large overshoot, it converges on the target position Xr. On the other hand, as described above, by correcting the current value of the operation signal, the time delay until the integration amount becomes large as shown by the solid line B in FIG. 3 is compensated, and the operation amount correction value Δic Thus, the force Fk of the spring 22 is suppressed, the overshoot is suppressed to be small, and the carriage 21 can be quickly positioned at the target position Xr.

Here, in the above embodiment, the manipulated variable correcting unit 12
Holds the current value IC1 (n-1) of the signal input from the LPF 11 at the timing immediately before the switching command signal from the controller switching command unit 9 is input, and holds it immediately after the switching of the signal by the controller switching unit 10. Although the signal of the current value IC1 (n-1) is output to the adder 13, the spring constant of the spring 22 supporting the carriage 21 of the actuator 1 and the position detection unit 2 detect it as shown in FIG. The operation amount correction value that causes the actuator 1 to generate a force required to extend the spring 22 based on the actual position of the carriage 21 may be calculated and held.

The operation amount correction unit 12 calculates an operation amount correction value Δic, which is a current correction value for correcting the force by the spring 22, from the spring constant k and the movement distance of the carriage 21 at any time, and calculates the calculated operation amount. The correction value Δic is input to the adder 13 and is added to the operation signal output to the driver 14 to cancel the disturbance d of the spring 22 applied to the actuator 1. Here, the origin for obtaining the moving distance does not necessarily have to be a position where the force of the spring 22 and the weight of the carriage 21 are in balance, and may be a negative direction from the position where they are in balance.

When the carriage 21 moves in the negative direction, the spring 22 extends and a force Fk is generated in the direction opposite to the direction in which the carriage 21 is propelled. If the origin is X0, the position of the carriage 21 is X, and the spring constant is k, the force Fk generated in the spring 22
Is as shown in the following equation.

[0039]

[Equation 5]

In order to suppress this force Fk, the increase value of the current that causes the voice coil motor 24 to generate force is taken as the manipulated variable correction value Δic. Let K be the thrust constant of the voice coil motor 24.
If f, then the following equation holds.

[0041]

[Equation 6]

Since the force Fk of the spring 22 is constantly suppressed by using the manipulated variable correction value Δic calculated using the above equation, the gain of the integral term for increasing the low frequency gain is not increased in order to reduce the deviation. In addition, the followability with respect to the target speed and the target position can be improved. Further, the deviation due to the delay of the integral term when the control by the speed controller 6 is switched to the control by the position controller 9 can be suppressed, and the deviation of the integral term can be reduced as compared with the case without correction (the case indicated by the dotted line C in FIG. 5). Since the gain is small, overshoot can be suppressed to a small value as shown by the solid line D in FIG.

Further, the operation amount correcting section 12 stores the position where the restoring force of the spring 22 and the weight of the carriage 21 are balanced,
A manipulated variable correction value Δic that causes the actuator 1 to generate a force necessary for expanding and contracting the spring 22 based on the spring constant of the spring 22 supporting the carriage 21 and the stored distance from the balanced position to the actual position of the carriage 21. May be calculated.

When the position where the force of the spring 22 and the weight of the carriage 21 balance in the initial state is Xs, the force Fk of the spring can be expressed by the following equation.

[0045]

[Equation 7]

The manipulated variable correction value Δic can be expressed by the following equation.

[0047]

[Equation 8]

Thus, by obtaining the operation amount correction value Δic in consideration of the balance of the carriage 21, it is possible to suppress not only the expansion of the spring but also the disturbance due to the contraction.

Further, the manipulated variable correcting unit 12 is necessary to extend the spring 22 based on the spring constant of the spring 22 supporting the actuator 1 and the actual position of the actuator 1 detected by the position detecting unit 2 as described above. A manipulated variable correction value that causes the actuator to generate a large force, and further calculates a manipulated variable correction value that corrects the influence of the frictional force based on the acceleration and frictional force of the actuator 1, and calculates both manipulated variable correction values. It may be added to the operation signal output to the driver 14. When the acceleration of the carriage 21 is α and the weight of the carriage 21 is M, its force Fa can be expressed by the following equation.

[0050]

[Equation 9]

The force Fm generated by the voice coil motor 24 can be expressed by the following equation, where Kf is the thrust constant and im is the motor current.

[0052]

[Equation 10]

Since Fa = Fm, the following equation holds.

[0054]

[Equation 11]

Therefore, assuming that the component for correction such as friction is if, the correction value Δic can be expressed by the following equation.

[0056]

[Equation 12]

As a result, as shown in FIG. 6, the followability during control by the speed controller 6 can be further improved. Here, the dotted line E in the figure is the target speed, and the solid line F
Is the speed of the carriage 21 when the above correction is performed, and G in the drawing is the carriage 21 when the above correction is not performed.
Shows the speed of.

Further, the operation amount correcting section 12 stores the position where the restoring force of the spring and the weight of the carriage 21 balance, as already described, and based on the spring constant of the spring 22 supporting the carriage 21 and the stored balance position. The manipulated variable correction value Δ that causes the actuator to generate the force required to expand and contract the spring based on the distance to the actual position of the actuator.
ic is calculated, and the operation amount correction value Δic for correcting the influence of the frictional force based on the acceleration and the frictional force of the carriage 21
May be calculated, and both calculated operation amount correction values may be output to the driver 14 in addition to the magnitude of the operation signal output to the driver 14. The correction value Δic in this case is as shown in the following equation.

[0059]

[Equation 13]

Here, the friction correction component if is changed by the acceleration switching load and the law. By performing the correction in this way, it is possible to further improve the followability when the speed control controller 6 performs the control.

Furthermore, when the control of the speed controller 6 is switched to the control of the position controller 9, the state variable of the position controller 9 and when the control of the position controller 9 is switched to the control of the speed controller 6. The state variable of the speed control controller 6 may be reset to the initial value. If the state variable is vector x, the input is vector u, and the output is vector y,
The following equation holds.

[0062]

[Equation 14]

When the control by the speed controller 6 and the control by the position controller 9 are switched, an overshoot occurs as shown by a dotted line H in FIG. 7 because the integral amount of the integral term of the newly connected controller is not appropriate. It may become large and the transient response may deteriorate. Therefore, by resetting the state variable vector x to be, for example, vector 0, the integral amount of the controller can be reset, and the overshoot can be reduced as shown by the solid line I in FIG.

Further, the state variable vector x is set to the vector 0.
Instead of resetting so that it becomes, the predetermined optimum vector xc may be set. As a result, the overshoot can be further reduced as shown by the solid line K in FIG.

[0065]

As described above, the present invention outputs an operation signal based on the target speed of the actuator and the actual moving speed of the actuator so that the moving speed of the actuator becomes the target moving speed, and the target of the actuator is output. An operation signal is output based on the position and the position of the actuator so that the actuator stop position becomes the target position, and both operation signals are switched based on the target position of the actuator and the actual position of the actuator , and further directed to the driver. Out
Input to the driver just before switching the operation signal to apply
Hold the operation signal as the operation amount correction signal and send it to the driver.
Operation held immediately after switching the operation signal to be output
Add the amount correction signal to the operation signal output to the driver
Since the output to the driver by, it is possible to perform quickly the actuator positioning control method according to the actual position and the target position of the actuator,
Minimize overshoot when switching control
it can.

[0066]

Further, just before switching the operation signal to be output to the driver, it is input through the low-pass filter,
Since the input operation signal is held as the operation amount correction signal, and the held operation amount correction signal is output to the driver in addition to the operation signal output to the driver, malfunction due to high frequency components such as noise can be prevented.

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[Brief description of drawings]

FIG. 1 is a configuration diagram of a positioning control device according to the present invention.

FIG. 2 is a side view of an actuator.

FIG. 3 is an explanatory diagram illustrating a locus of a carriage when corrected by a signal before switching.

FIG. 4 is a connection diagram of an operation amount correction unit that calculates an operation amount correction value from a carriage position.

FIG. 5 is an explanatory diagram illustrating a trajectory when correction is performed based on the position of the carriage.

FIG. 6 is an explanatory diagram illustrating a trajectory when correction is performed based on the position and friction of the carriage.

FIG. 7 is an explanatory diagram illustrating a trajectory when a state variable is reset to 0.

FIG. 8 is an explanatory diagram illustrating a trajectory when a state variable is set to a predetermined value.

[Explanation of symbols]

1 actuator 2 Position detector 3 Speed detector 4 Target speed calculator 5 Speed comparator 6 Speed controller 7 Position comparator 8 Position controller 9 Controller switching command section 10 Controller switching unit 11 LPF 12 Operation amount correction unit 13 adder 14 drivers 21 carriage 22 spring 25 encoder

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G05D 3/00-3/20 G05B ⁷ /00-7/04 G05B 11/00-13/04

Claims (2)

(57) [Claims] 1. An actuator, a position detector, a speed detector, a target speed calculator, a speed controller, a position controller, a controller switch and a controller switch.
It has a command unit, an operation amount correction unit, an adder, and a driver.The actuator is supported by a spring and moves along a guide according to a drive signal from the driver, and a position detection unit detects the position of the actuator, The speed detection unit detects the moving speed of the actuator, and the target speed calculation unit calculates the target speed that is the target speed of the actuator movement based on the target position of the actuator and the position of the actuator detected by the position detection unit. The control controller outputs an operation signal based on the target speed calculated by the target speed calculator and the actuator moving speed detected by the speed detector so that the actuator moving speed becomes the target moving speed. Actuator stop position based on the target position of the actuator and the position of the actuator detected by the position detector. There outputs an operation signal so that the target position, the controller switching unit speed controller has outputted
The operation signal and the operation signal output from the position controller
To output to the adder, and the controller switching command section sets the actuator target position and
And the position of the actuator detected by the position detector,
Which operation signal is added to the controller switching unit
Output to the speed control command input from the controller switching unit.
Operation signal output from controller or position control controller
Controller and one of the operation signals output by the
The operation held immediately after the roller switching unit switches the operation signal.
Add the operation amount correction signal input from the work amount correction unit
Output to the driver, the operation amount correction unit holds the added operation signal from the adder as the operation amount correction signal immediately before the controller switching unit switches the operation signal, and the driver sets the input operation signal to the same magnitude. A positioning control device which outputs a drive signal for an actuator in response to the actuator. 2. The operation amount correction unit inputs the operation signal output to the driver by the controller switching unit via a low pass filter, and inputs the operation signal via the low pass filter immediately before the controller switching unit switches the operation signal. The positioning control device according to claim 1, wherein the operated operation signal is held as an operation amount correction signal.