JPS62182803A - Position controller - Google Patents

Abstract

PURPOSE:To set quickly and stably a controlled system to an allowable range of the final control target value by using the integration gain with which a servo system is stable and another integration gain larger than the first one with switching. CONSTITUTION:When deviation epsiloni is supplied to an integrator 1, an arithmetic circuit 2 calculates integral epsilonidt and at the same time an absolute value circuit 6 converts the value integral epsilonidt into the absolute value ¦epsiloni¦. Then a comparator 7 compares the value ¦epsiloni¦ with the prescribed reference value epsilonp. thus the signal of a high level is delivered to a changeover switch 5 in case of ¦epsiloni¦>epsilonp. Receiving said signal, the switch 5 is connected to the side B. Thus the large integration gain Kpi set by a gain setting device is given to the arithmetic result of the circuit 2. Then the output I'=Kpi and integral epsilonidt are given to a servo system. Thus the quick position control is possible with a position controller.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a position control device applied to industrial robots, XY stages, etc., and particularly relates to a servo system of this type of position control device. The present invention provides a novel integrator for quickly and stably bringing a controlled object within the allowable range of the final control target value.

<Background of the Invention> As shown in FIG. 5, a conventional position control device of this type uses current position data (hereinafter simply "
A position feedback loop 22 that feeds back the current speed data (referred to as "current value")
3. In the position feedback loop 22, the deviation ε between the control target value X0 and the current value XR is determined, and the moving body 2 is adjusted so that this deviation ε becomes zero.
Positioning control to the first target position is performed. The deviation ε
is input to the integrator 24 and integrated in order to make the steady position error zero, and then in the next block 25 compensation is provided to improve the control characteristics of the position feedback loop 22, and further in the next block 26 the gain is It gives KA. The speed feedback loop 23 is used to provide a damping element to the servo system of the moving body 21, and in block 27, compensation is provided to improve the control characteristics of the speed feedback loop 23, and in the next block 28, the gain Ks is is giving.

By the way, the integrator 24 has the final control t'ltl I''
The integrator 24 is operated after the target value is obtained.If the integral gain of this integrator 24 is Kpi, its output I is as shown in the following equation 0.

1 = 3, engineering εdt −−−−−−−・−・■ Conventionally, in this type of integrator 24, the optimal integral gain K pi is set so that the servo system is stable. When the gain Kpi is used, there is a problem in that it takes an extremely long time for the controlled object to fall within the allowable range of the control target value, making quick position control difficult.

<Object of the invention> This invention is intended to solve the above problems,
By switching between an integral gain that stabilizes the servo system and an integral gain that is larger than this integral gain, this new system can quickly and stably bring the controlled object within the allowable range of the final control target value. The purpose of the present invention is to provide a position control device.

<Structure and Effects of the Invention> In order to achieve the above object, the position control device of the present invention includes a calculation means for inputting the deviation between the final control target value and the current value of the controlled object and performing an integral calculation, and this calculation means. a first gain setting means for giving an optimal integral gain for stabilizing the servo system to the calculation result value; and a second gain setting means for giving the calculation result value a larger integral gain than the optimal integral gain. The system is equipped with a gain setting means, a comparison means for comparing the magnitude of the deviation with respect to a predetermined reference value, and a switching means for switching and setting one of the integral gains based on the comparison result by the comparison means.

According to this invention, when the deviation between the final control target value and the current value of the controlled object is larger than the predetermined reference value, a large integral gain is given by the second gain setting means, and the deviation is set to the reference value. When the following is achieved, the optimal integral gain can be given by the first gain setting means, so the controlled object can be quickly and stably brought within the allowable range of the final control target value, etc. A remarkable effect has been achieved in achieving the purpose of the invention.

<Description of Embodiments> FIG. 1 shows an integrator 1 included in a position control device of the present invention.
An example is shown below. This position control device is for moving and positioning a controlled object to a target position in an industrial robot, an XY stage, etc., and has the same configuration as that shown in FIG. 5 described above (description omitted). .

The integrator 1 shown in FIG. 1 includes an arithmetic circuit 2 that inputs the deviation ε between the final control target value and the current value of the controlled object and calculates 5ε and dt, as well as two gain circuits. Setting device 3
．． 4. Changeover switch 5゜Absolute value circuit 6, comparator 7
It is made up of etc.

The gain setters 3 and 4 are for giving a predetermined integral gain to the calculation result value by the arithmetic circuit 2, and one gain setter 3 gives the optimum integral gain Kpi to stabilize the servo system. The other gain setter 4 provides an integral gain K pi' larger than the integral gain K pi. The absolute value of circuit 6 is the deviation ε, whose absolute value is 16.1
Convert to The comparator 7 is for comparing the magnitude of the above-mentioned absolute value 1ε11 with respect to a predetermined reference value ε3. The signals at the LO-'' level are output to the respective changeover switches 5.

This selector switch 5 is used to switch and set one of the integral gains Kl)j+Kl)j' according to the comparison result by the comparator 7. When the comparator 7 outputs a LOW level signal, the switch 5 becomes the A side, and the switch becomes the B side when the comparator 7 outputs the old G1 bilevel signal.

When the deviation ε, is input to the illustrated integrator 1, the arithmetic circuit 2 calculates the deviation ε, dt, and the absolute value circuit 6 converts it into an absolute value 1ε,1. Then, the comparator 7 goes off and compares the magnitude of the 1 value lε11 with a predetermined reference value ε9, and when 1ε, 1>ε, “lllG
A signal of level 11 is output to the changeover switch 5. The changeover switch 5 receives this signal and connects the switch to the B side, so that the gain setter 4 provides a large integral gain K pi' to the calculation result value of the calculation circuit 2. And this output 1'=Kp,'kε
, dt to the servo system, rapid position control is achieved.

Figure 2 shows the absolute value of deviation ε over time: 1ε41
shows the change characteristics of According to the diagram, the change characteristics are 1ε, 1
When >ε, the curve becomes steep with respect to the passage of time t, indicating that a rapid control operation is being performed during this period.

In this way, when the controlled object approaches the control target value and the comparator 7 determines that 1ε11≦ε9, a “LO-” level signal is output to the changeover switch 5, and the switch is set to A.
connected to the side. As a result, the integral gain K p obtained by the other gain setter 3 is calculated based on the calculation result value obtained by the calculation circuit 2.
i will be given, and this output I = K-tJ
By outputting ε and dt from the integrator 1 to the servo system, stable position control without oscillation is performed.

In FIG. 2, the change characteristic of Igil≦ε is a gentle curve with respect to the passage of time t, indicating that stable position control is being performed during this time.

FIG. 3 shows an example of a circuit configuration for realizing the above-mentioned integral function through software control.
Micro Processor Unit) 10
A servo system control ROM 12 and a RAM 13 are electrically connected to the main control ROM II via a bus 14. The main control ROM II has the following functions when it is necessary to activate or stop the integral function:
Information to that effect is stored in a predetermined area of the RAM 13 (for example, when the operation starts, the rlJ flag is set, and when the operation is stopped, the
The software is set to write a flag of "0"). Further, software is set in the servo system control ROM 12 to read information from the RAM 13 every servo cycle, and to activate or stop the integral function based on the continuously read information. The MPU10 decodes and executes the programs stored in each of the ROMs 11 and 12, and performs various calculations and processes while reading and writing information to the RAM 13.

FIG. 4 shows the control procedure of the MPU 10 to realize the integral function. In the illustrated example, the MPU 10 first reads out information regarding the start and stop of integration from a predetermined area of the RAM 13 in step 1 (indicated by rsTLJ in the figure), and determines whether it is operation start information or operation stop information. If it is determined that it is operation start information, step 1 becomes YES', and the next step 2 calculates the deviation ε1 between the final control target value θ and the current value θ,1 of the controlled object, and then In step 3, the integral value Σ of the deviation ε,
ε is calculated and saved in the RAM 13. Next, MPIJlo compares the absolute value 1ε51 of the deviation ε1 with the reference value ε2 in step 4, and when the determination in step 4 is "YES"(1εL1>ε2), in step 5 the integral value Σε.

and a large integral gain K. ′ and the output 1
Send r=K pi rΣεi to the servo system.

On the other hand, when the determination in step 5 is “NO” (1ε,
1≦ε2), proceed to step 6 and calculate the integral value Σ
ε, and the optimal integral gain K pi to stabilize the servo system.
Then, the output 1=, Σε1 is sent to the servo system.

Note that in step 1, when it is determined that MPUl0 is operation stop information, the determination in step 1 is "NO".
”, the program proceeds to step 7, and the integral value Σε4 set in the RAM 13 is cleared.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing an example of the circuit configuration of an integrator according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing changes in deviation with respect to time, and FIG. FIG. 4 is a flowchart showing the control operation of the embodiment of FIG. 3, and FIG. 5 is a block diagram showing the overall structure of the position control device. 1...Integrator 2...Arithmetic circuit 3.
4... Gain setting device 5... Selector switch 7... Comparator 10... MPUlL
12...ROM 13...RAM
Nia +/) Z, f & Ryurei 9th Fushizu 4 gain establishment foot association.

Claims (1)

[Scope of Claims] A position control device for moving and positioning a controlled object to a target position, comprising calculation means for inputting a deviation between a final control target value and a current value of the controlled object and performing an integral calculation; a first gain setting means for giving an optimal integral gain for stabilizing the servo system to the calculation result value of the calculation means; and a first gain setting means for giving the calculation result value an integral gain larger than the optimal integral gain. It comprises a second gain setting means, a comparison means for comparing the magnitude of the deviation with respect to a predetermined reference value, and a switching means for switching and setting one of the integral gains based on the comparison result by the comparison means. Position control device.