JPS6016641B2 - On/off control method - Google Patents

Description

[Detailed Description of the Invention] {a) Description of the Technical Field The present invention provides an on-off control system that improves control accuracy through pulse control when fixed-value control of processes or follow-up control of machine tools is performed using on-off control. The present invention relates to an off control method and device.

'b' Explanation of Prior Art Conventional on/off control devices control the controlled object to simply increase, maintain the status quo, decrease, or take a positive It attempts to approach the target value by giving a three-value operation signal indicating whether to move, maintain the status quo, or move in a negative direction, and the control accuracy is mainly determined by the inertia of the controlled object.

FIG. 1 shows a block diagram of the follower method.

In Fig. 1, the target value A set by the reference setting device 1 and the control output Discriminator 2
If A>×, a signal is sent to the controlled drive device (hereinafter simply referred to as the drive device) 3 to increase the control output, and if A<×, the drive A signal is sent to device 3 to reduce the control output. As a result, as shown in Figure 3, for example, the eye blind value changed from B to A. In the case of switching, when the control output x enters within the width range D of the polarity discriminator 2 at time t, the drive signal C from the polarity discriminator 2 to the drive device 3 stops, and the control output With the inertia of 3, it moves until time t and becomes the final value x, leaving an error e8. The value of e8 is determined by the width of the belt and the inertia of the drive device 3, and the latter changes with the aging of the drive device 3 and is not always a constant value. Therefore, the width of the belt should also have some margin. This has the disadvantage that the accuracy of the system is also limited by this value. {c'Object of the Invention The present invention, after the control output enters the uncontrolled band width, drives the drive device in pulses with a time width corresponding to the control deviation between the target value and the control output, thereby eliminating the need for the control device. An object of the present invention is to provide an on/off control method that can improve control accuracy without frequently repeating on/off operations.

'd} Description of the Invention The present invention will be described below with reference to an embodiment shown in FIG.

In the conventional circuit, the value A of the setting device 1 and the control output When the output is off, that is, when the control deviation e is within the range value of the polarity discriminator 2, the NOT circuit 4 outputs an output, opens the gate of the gate circuit 5, and sends the control deviation e to the integrator 6. The integrator 6 integrates the input value e when the output of the integral reset oscillator 8 is on, and makes the integrated value zero when it is off. The output of the integrator 6 is sent to an auxiliary polarity discriminator 7, and when the value of the integrator 6 exceeds a certain value, a drive signal is sent to the drive device 3 to increase or decrease the control output. As a result, when the control output falls within the dead band width of 2, it becomes a value pulse-driven with a time width corresponding to the control deviation e.

This situation is shown in FIG. Set the target value as shown in Figure 5b,
For example, when changing from B to A, the polarity discriminator 2 first outputs a signal as shown in FIG.
It works to increase the output as shown in the figure. When the dead zone value -D is entered, the output of the magnetic discriminator 2 is turned off, and from time t, to t,'
The control output x changes depending on the inertia of the drive device and load. On the other hand, the control deviation e is integrated as shown in FIG. 5 e while the transmitter 8 is on as shown in FIG. 7 to the driving device 3 via the OR circuit 9 at the time f in FIG. 5 to t4.
, t7 to t7. Since the output of the integrator 6 is the integrated value of the control deviation, the time width of the pulse drive by the auxiliary polarity discriminator 7 naturally changes in accordance with the control deviation. As is clear from Fig. 5, when the control deviation c becomes smaller, the amount of pulse drive also becomes smaller correspondingly, which is much improved over conventional on-off control without causing instability due to over-control. The driving period can be freely varied by changing the oscillator frequency and the integrator time constant.
There is no need to repeat on/off operations unnecessarily.

In this way, according to the method of this invention, it is possible to control the drive mechanism and therefore the load stably and accurately, and since the drive device and load are not made to make unnecessary movements during settling, it is possible to control the mechanical parts. This has the effect of preventing wear and unnecessary loss of driving power.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the follower device, FIG. 2 is a characteristic diagram of the polarity discriminator, FIG. 3 is a characteristic diagram showing the control state by the conventional device, FIG. 4 is a block diagram of the device of the present invention, and FIG. Figures a to f are time charts showing control states according to the method of the present invention. 1...Reference setter, 2...Polarity discriminator, 3...
. . . Drive device for controlled object, 4 . . . Knot circuit, 5 . . . Gate circuit, 6 . . . Integrator, 7.
...Auxiliary polarity discriminator, 8... Integral reset oscillator, 9... OR circuit. Figure 1 Figure 2 Figure 3 Figure 5 Figure 4

Claims (1)

[Claims] 1. When the control deviation between the reference setter output and the control output exceeds the first dead band width, the drive device of the controlled object is controlled with a control output of a constant value of polarity corresponding to the polarity of the control deviation. , when the control deviation becomes equal to or less than the dead band width, the control deviation is integrated at a certain period for a certain period during that period and then reset, and the integrated value is calculated only during the period when this integrated value exceeds the second dead band width. An on/off control method for controlling the drive device of the controlled object with a control output having a constant value of polarity corresponding to the polarity of the control target.