JPH011002A - Wide-area stabilization filter for feedback control system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention is a feeder that controls machines all at once.

This paper relates to wide-area stabilization filters applied to control systems.

[Conventional technology]

One method of controlling the speed and position of a machine is feedback control, which measures the speed and position of the machine and applies force to the machine so that there is no difference between the measured signal and a set value.

A speed feedback control device will be explained here as an example of the conventional example, but the diagram shows a block diagram of the speed control of a normal machine, and 7 is the mechanical system to be controlled. 6 is an actuator that applies force to the mechanical system 7; 9 is a speed feedback system that feeds back the speed signal V of the mechanical system 7; and 8 is a speed feedback system that feeds back the speed signal V from the mechanical system 7; It is a comparator for comparison.

The signal V is applied to the actuator 6, and the mechanical system 1 is turned on so that the difference between the actual speed V of the mechanical system 7 and the set value U becomes zero.
Apply force F to . If the actuator 6 is a mechanical system 7 such as a hydraulic servo, it will show the following second-order delay system.

Here, S is the Laplace transform, fA is the natural frequency (Hz) of the actuator 6, ζ is the damping ratio, and K is a constant. The (force F)/(velocity V) for the mechanical system 7 is (
1) is multiplied by a minus, and the dein and phase of (F/V) are shown in Figure 1. On the other hand, the mechanical system is
It is expressed as CX'juzu = F (2).

Here, X represents displacement, ' represents differential, M represents mass, C represents damping coefficient, and K represents spring constant. speed signal viix
', the real part of p/V, that is, the following equation becomes the attenuation term.

F = -Acx1s91 @X'
(3) Here, A is the formula (1), FIG. 4 (a) shows the phase (ψ), and the ?th ? Figure 9(b) shows the dynes. Substituting equation (3) into equation (2), MX'+ (C+ ACOIψ) -X'+fCX =
It becomes O(4).

If the phase ψ is between π/2 and -π/2, the feedback system 9 works to stabilize the mechanical system 7, and otherwise works to destabilize it. Therefore, the natural frequency t of the mechanical system 7
M=Moe/z K is the natural frequency fA of the actuator 6
If it is higher than that, the feed pump system 9 tends to destabilize the mechanical system 7, and when (C+Aμsψ)<0, the natural frequency fM of the mechanical system 7 causes divergent vibrations, making it impossible to operate.

A similar phenomenon occurs in the feeder system 9 that feeds back position and acceleration signals.

[Problem that the invention seeks to solve]

As mentioned above, the conventional speed feedback control device has the disadvantage that the mechanical system 7 is made unstable due to the phase delay of the feeder and the yarn 9, and that divergent vibrations are generated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a wide-range stabilizing filter for a feedback control system that can be used in a feedback system to stabilize the destabilizing force generated by the feedback system.

[Means for solving problems]

In order to achieve the above object, the present invention inputs the input signal of a feedback control system to two branched systems, and stabilizes the input signal input to one of the systems by applying a force lower than the natural frequency to stabilize the input signal input to one of the systems. The input signal input to the other system is passed through a low-pass filter with a cut-off frequency lower than the natural frequency to be stabilized, and then passed through a high-pass filter with a cut-off frequency lower than the desired natural frequency. The output g! The signal obtained by subtracting the output signal of the high-pass filter from number i is output as the output signal of the feedback control system.

[For production]

With the present invention configured as described above, high frequency component signals that have a destabilizing effect on the natural frequency of the mechanical system are interrupted by the low pass filter.

It is passed through the other high-pass filter, the polarity of which is inverted by subtraction, and the ft9p signal is used as a stabilizing signal.

will be removed.

Further, since the low frequency component passes through the low pass filter without being interrupted, and is interrupted through the high pass filter, the polarity is fed back as is, and does not cause any trouble to the control.

Therefore, phase compensation can also be performed for the natural frequency of the mechanical system, which is set in a high frequency region.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the glue TL of the present invention, in which 1 is an LC consisting of an inductance and a capacitor.
In the form, a low-pass filter is represented by a Patwas or Tievisiev type, a high-pass filter is represented by a type similar to the 2f low-pass filter 1, and a d1 overfilter. 3 represents a subtracter.

In Figure 41, the input signal of the feed control system is input to two branched systems, one input signal is input to the low-pass filter 2, and the other input signal is input to the high-pass A pass filter 2. is input. The outputs of the low-pass filter 1 and the high-pass filter 2 are input to a subtracter 3.
The output obtained by subtracting the output of the high-pass filter 2 from the output of the low-pass filter 1 is output.

FIGS. 2(a) and 2(b) show typical phase and gain characteristics of a low-pass filter 1 having a cutoff frequency fl.

Also, FIG. 3 (&) and (b) show the cutoff frequency f.

2 shows typical phase and gain characteristics of a high-pass filter 2 with .

The phase diagram and gain characteristics of the stabilizing filter shown in Fig. 1, which is composed of the low-pass filter 1 with the characteristics shown in Fig. 2 and the high-pass filter 2 with the characteristics shown in Fig. 3, are shown in Fig. 4 (&) @ (b). become that way. Although FIG. 4 shows an example in which the power of the low-pass filter 1, the cut-off frequency f1, and the cut-off frequency f of the high-pass filter 2 match, the cut-off frequencies f□ and f may not necessarily match. . The characteristics of the stabilizing filter in Figure 4 are the cutoff frequency f, =f, =f*
The gain increases slightly in the vicinity, but the gain characteristics remain almost constant.

f, the phase is zero at lower frequencies, and f, the phase is 180° (π) at higher frequencies, varying.

FIG. 5 shows the stabilizing filter shown in FIG. 1 applied to the conventional mechanical speed control device shown in FIG. 8, and the stabilizing filter 4 shown in FIG. 1 inserted into the speed feedback system 9. , is.

Cutoff frequency f of low-pass filter 1 and high-pass filter 2 of stabilizing filter 4, (=ft=fm)
The phase and gain characteristics of (force F)/(velocity KV) when set at a point slightly lower than the natural frequency fMc of the mechanical system are as shown in FIGS. 6(a) and (b). Even in the high frequency range including the natural frequency fMC of the mechanical system, the gain l F/V
1, as is clear from the comparison between FIG. 6 and the layer diagram, the conventional example and the embodiment of the present invention are almost the same, and the phase is positive.

Therefore, Acosψ in equation (3) is positive and stabilized with respect to the seventh natural frequency fMc of the mechanical system. In fact, the mechanical system 7 has multiple degrees of freedom, has several natural frequencies at frequencies higher than fMc, and has a stabilizing effect on the entire mechanical system 7.

In the embodiments described above, the cutoff frequencies of the low-pass filter 1 and the high-pass filter 2 are made the same, but they may be different, and the frequency range in which the phase changes can be adjusted according to the amount of difference. The amount of attenuation can also be adjusted by changing the position.

[Effects of the Invention] According to the present invention, the input signal of the feed control system is input to two branched systems, and each input signal is passed through a low-pass filter and a high-pass filter. Since the output signal of the filter minus the output signal of the high-pass filter is output as the output signal of the feed control system, it also has a stabilizing effect in the high frequency region where the natural frequency of the mechanical system exists. can be added,
And the feedback dyne is still the same.

It is possible to provide a wide-range stabilizing filter with a feedback control system that is good against noise.

[Brief explanation of drawings]

The IT diagram is a linear diagram showing an embodiment of the wide-area stabilizing filter of the feedback control system of the present invention. FIG. 2 is a transfer characteristic diagram of the low-pass filter shown in FIG. 1. Figure 3 is a transfer characteristic diagram of the high-pass filter in Figure 1;
The figure is a transfer characteristic diagram of the stabilizing filter shown in FIG. FIG. 5 is a block diagram showing an example in which the stabilizing filter of FIG. 1 is applied to a conventional mechanical speed control device, 8146,
The figure is a transfer characteristic diagram of the feeder system shown in Figure 5. FIG. 4 shows a block 1w factor showing an example of a conventional mechanical speed control device, and FIG. ψ is a transmission characteristic diagram of the speed feed 1 pack system shown in FIGS. 1...Low-pass filter, 2...High-pass 4-pass filter. 3...Subtractor, 4...Stabilizing filter, 6...Active. 2...Mechanical system, 8...Comparator, 9...Speed feeder. Applicant's agent Patent attorney Takeshi Suzue Hikogame 1 r3 @5

Claims (1)

[Claims] The input signal of the feedback control system is input to two branched systems, and the input signal input to one of these systems is passed through a low-pass filter with a cutoff frequency lower than the natural frequency to be stabilized. After passing the input signal input to one system through a high-pass filter with a cutoff frequency lower than the natural frequency to be stabilized, the output signal of the high-pass filter is converted from the output signal of the low-pass filter. A wide-area stabilizing filter for a feedback control system that outputs a signal obtained by subtracting .