JPH01296321A - Positioning controlling method - Google Patents

Abstract

PURPOSE:To position a movable member with high accuracy by quickly converging the movable member to an aimed position by means of signals proportional to the positional deviation values of the member when the speed of the member is fast and adding the integrated value of the deviation values to the signals when the member approaches the aimed position. CONSTITUTION:The speed of a positioning table 3 is sampled (k) times per hour and the sum of the absolute values of the speeds Vn is found. When the speed becomes slower than a prescribed value (alpha) and the table 3 approaches an aimed position, an integration circuit 6 is inserted by means of a switch A. A speed conversion circuit 7 inputs a position measuring value X and outputs a speed S to a speed gain circuit 8 after converting the value X into the speed S. The circuit 8 multiplies the inputted speed S by a speed gain Kv and outputs a signal I4 corresponding to the measured speed to a subtractor P3. A driver 1 drives a linear motor 2 by using a value obtained by multiplying the output (I3-I4) of the subtractor P3 by a driver gain KD, namely, a position adjusting value. By using such constitution, the responsiveness of the proportional control and the vibration amplitude are prevented from getting worse and from being expanded so as to highly accurately position the movable member at a high speed.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for controlling positioning of various automatic devices.

(Prior Art) A conventional positioning control method uses a position deviation value, which is the difference between a position specification value indicating the position to be reached by the object to be positioned or the mechanical part driving it, and the current position measurement value. Proportional control that outputs a reference speed signal that gives the corresponding speed to the motor drive circuit, and outputs the result of subtracting the reference signal and the measured speed to the motor drive circuit, and calculates the integral value of the position deviation over a predetermined time as described above. There was proportional-integral control in which the integral value multiplied by the adjustment value was added to the standard speed and used as a speed signal.

Proportional control has the advantage that convergence can be made sufficiently fast depending on how the adjustment values are selected. However, when a regular external force that tries to shift the position of the object acts, a positioning error occurs. On the other hand, in proportional-integral control, positioning errors can be eliminated by the integral function. However, there are problems in that the positioning response becomes slow, and depending on the value of the adjustment value, vibration may become large or the stopping position may shift.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems, and does not cause positioning errors even when receiving a regular external force that occurs during positioning.
An object of the present invention is to provide a positioning control method that enables positioning in a short time.

(Means for Solving the Problems) As a method for achieving the above object, the present invention provides a method for making a movable member driven by a motor reach a position of a specified position value by using the difference between the position command value and the position measurement value. In a control method for positioning using a signal that is the product of a position deviation value and an adjustment value of a contact value, in the process of reaching the specified position value, the sum of the absolute values of velocities within a predetermined time is less than a predetermined value. When the value is small, the signal obtained by adding the product of the integrated value of the position deviation value and the cough value adjustment value to the signal is used as the reference speed signal of the motor, and the signal obtained by subtracting the measured speed signal from this signal is used. The movable member is caused to reach the position of the specified position value by controlling the front motor.

(Function) The present invention calculates the sum of sampling values of the velocity of a movable member within a predetermined time, and when this is larger than a predetermined value, a signal proportional to the position deviation value is used, and when it is smaller, this signal is used to calculate the position deviation value. A signal obtained by adding a signal proportional to the integrated value of the deviation value is defined as a reference speed signal. By driving the motor using a signal obtained by subtracting the measured speed signal from this signal, the movable member is caused to reach the designated position.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the positioning control method of the present invention.

The driver 1 drives the positioning table 3 to move it over the linear motor 2 to a predetermined position. The encoder 4 receives a position measurement value X indicating the position of the positioning table 3.
Output. The position command value X and the position designation value X are input to the subtracter P1, and a position deviation value (XaX) is output. When switch A is used, position gain circuit 5
input the deviation value (Xo
The adjusted value) is multiplied by Ko and output to the adder P to perform proportional control. When switch A is closed, the position deviation value (XO-X) is input to the integrating circuit 6, and a signal proportional to l/CS (Xo-X)dt, which is the integral value multiplied by the integral gain l/C, is generated. 12 is output to the adder P2, and the adder P uses the signal (1+ +11) as the reference speed signal to the subtracter P.
Output to 3.

FIG. 2 shows the control of switch A. (a) of the figure shows a change in the position measurement value X with respect to the position command value X.

The speed of the positioning table 3 is sampled once per hour and is given by equation (1), which is the sum of the values.

Σ1val<α... (1) Switch A is turned on when the speed of table 3 in equation (1) is smaller than a predetermined value α, and integration circuit 6 is inserted.

When it is larger than the predetermined value α, switch A is turned off and the integrating circuit 6 is not inserted.

The speed conversion circuit 7 inputs the position measurement value X, converts it into a speed S, and outputs it to the speed gain circuit 8. Speed gain circuit 8
is the signal I corresponding to the measured speed by multiplying the input by the speed gain Kv
4 is output to the subtractor P.

The driver 1 drives the linear motor 2 with a signal obtained by multiplying the output signal (I, -4) of the subtractor P3 by a driver gain Kll.

Next, the operation of the embodiment will be explained with reference to the flowchart shown in FIG. In step 20, the values of signals 1 to I are reset to 0, and then in step 21, the number of empty pulls is reset to 0. In step 22, position deviation values (X, -X) are calculated. At step 23,
For speed calculation, the speed conversion circuit 7 converts the speed from the position deviation value, and then the speed gain circuit 8 converts the measured speed signal ■
, is output, and at step 25, n is directly incremented by +1. At step 26, n=
It is checked whether it is k or not, and if it is not, the process returns to step 25 and +1 is repeated. If n= in step 26, step 2
If Σ1v71 is smaller than α, switch A is turned on to output the proportional control signal ■1, and the process advances to step 7. If it is larger, the integral control signal rz=1/C3(XO-X)dt is calculated in step 28. At step 29, signals 11 and I2 from steps 28 and 29 are added to obtain a reference speed signal I3. Step 30
The standard speed signal I at step 23 and the specified speed signal I at step 23
4 is input to driver 1. In step 31, the driver 1 drives the linear motor 2 using a signal obtained by multiplying the driver gain by 0 to the signal N:+14) to cause the positioning table 3 to reach the specified position.

(Effects of the Invention) As explained above, when the speed of the movable member is high, convergence to the target position is accelerated by a signal proportional to the position deviation value between the position command value and the position measurement value, and the speed is lower than the predetermined value. When the deviation value is small, that is, when the target position is approached, a signal of a value obtained by integrating the deviation value is added to the above-mentioned signal to eliminate positioning errors and perform accurate positioning. This prevents poor responsiveness and vibration amplitude of proportional control from increasing, and enables high-speed and highly accurate positioning.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the positioning control method of the present invention, FIG. 2 is a characteristic diagram thereof, and FIG. 3 is a flowchart showing the operation of FIG. 1. 1...Driver, 2...Linear motor, 5...
Position gain circuit, 6...Integrator circuit, P,, P,...
Subtractor, P2...adder.

Claims (1)

[Claims] In order to cause the movable member driven by the motor to reach the specified position value, positioning is performed using a signal that is the product of a position deviation value, which is the difference between the position command value and the position measurement value, and an adjustment value of this value. In the control method, in the process of reaching the specified position value, when the sum of the absolute values of the speeds within a predetermined time is smaller than a predetermined value, the product of the integrated value of the position deviation value and the adjustment value of the value is A signal obtained by adding the signal to the above signal is used as a reference speed signal for the motor, and the movable member is brought to the position of the specified position value by controlling the front motor to be driven by a signal obtained by subtracting the measured speed signal from this signal. A positioning control method characterized by: