JPH01191201A - Automatic control system - Google Patents

Abstract

PURPOSE:To constitute the control system in which a relation of a desired value R(S) and a controlled variable C(S) is scarcely influenced by a parameter fluctuation of an object to be controlled and a disturbance by adding two pieces of gain elements, two pieces of controllers and one piece of subtracter. CONSTITUTION:Gain elements 8, 8' consist of 1/k and 1-k, when (k) is a constant of 0<=k<=1. Also, controllers 10, 10' are controllers having a transfer characteristic of [1/G'(S)] and H'(S), respectively, when G'(S) and H'(S) are forward transfer functions G(S), and a feedback transfer function H(S) is a simulated transfer characteristic. That is, they are constituted so as to become [1/G'(S)]=[1/G(S)] and H'(S)=H(S) as much as possible. With regard to the gain element 8 and an automatic control system 9, when a direction of its signal is inverted, and also, (k) is set to zero, the gain of a gain element 12 becomes zero, and the system is detached in this part. Therefore, a desired value R(S) and a controlled variable C(S) are related well-definedly only by a range of the controllers 10, 10', an adder 7 and the gain element 8', and come to have no relation to an automatic control system 9' and a disturbance D(S).

Description

[Detailed description of the invention] [Industrial field of application] It is useful for automatic control systems and automatic control devices that are desired to be unaffected by parameter fluctuations and disturbances of the controlled object, and is particularly useful for industrial robots, machines, and machine tools. .

This invention relates to an automatic control method that can be used for servomechanisms widely used in computer peripherals.

[Conventional technology]

Generally, the system shown in FIG. 4 is known as one that utilizes an automatic control system.

FIG. 4 shows the configuration of a conventionally used closed loop automatic control system.

That is, G(8) in 3 is a forward transfer function, and specifically represents a control device or a controlled object. H(S) in 5 is a feedback transfer function, and the control amount (0
(S)] detection device and control device for closed loop stabilization. y(s) of 4 is a transfer function of the disturbance D(8), 1 is a subtracter, 2 is an adder, and R(8) is a target value.

[Problem that the invention seeks to solve]

In FIG. 4, the relationship between target value R(8) and control amount 0(S) can be expressed by the following basic equation.

As is clear from equation (1), even if the target value R(8) is constant, G(S)3 due to parameter fluctuations of the controlled object.
When G(S) changes or disturbance D(S) is added, the control to(S) fluctuates due to these influences, and a true control characteristic is obtained. As a countermeasure to this, G(S)→ If ω, then C(S) becomes, which can reduce the influence of fluctuations in G(S)3 and disturbance D(S), but the higher the gain of G(8)3, the more stable the closed loop becomes. This made it difficult to implement and had little practicality.

[Means for solving problems, effects, examples]

In view of the above-mentioned points, the present invention provides an automatic control system that can realize an automatic control system that is less susceptible to parameter fluctuations and disturbances of a controlled object.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 shows an example of the main part configuration to which the present invention is applied.
6 is a subtracter, 7 is an adder, 8 and 8' are gain elements,
1 is an automatic control system, and 10 and 10' are control devices.

Here, the automatic control system 91 is the conventional automatic control system shown in FIG. Adder 92. Forward transfer function [:G(S)]93. Transfer function of disturbance D(S) (Y(8
)194 and feedback transfer function (H(S):1
Consists of 95.

In FIG. 1, the gain elements 8, 8' are (1/k) and (1-k), where k is a constant (0≦≦1).
Consisting of Further, the control devices 10 and 10' are G'(S).

If H'(S) is a transfer characteristic simulating a forward transfer function G(S) and a feedback transfer function H(S), they have transfer characteristics of [1/G'(S)] and H'(S), respectively. It is a control device.

That is, as far as possible, [1/G'(8)] = (1/G
(S)].

It is assumed that the configuration is such that H'(S)=H(S).

Next, the automatic control system shown in FIG.
The fact that it is not easily affected by parameter fluctuations of S) and disturbance D(S) will be explained in detail.

FIG. 2 shows a method for reversing the direction of the signal in the control block diagram. (a) shows that the subtraction mode can be rewritten into the addition mode, and (b) shows that the transfer function F is ( 1/F) indicates that they can be replaced. In addition,
Regarding the conversion of F with , see Transactions of the Institute of Electrical Engineers of Japan, 87-3
(1967) by Takai, ``How to draw professional line diagrams and its application to analog stains, rays, and n'' will help you understand this.

Furthermore, if the signal direction of the gain element 8 and the automatic control system shown in FIG. 1 are reversed using such a method and k is set to zero, then FIG. 3 is obtained. In other words,
In terms of control characteristics, FIGS. 1 and 3 are completely equivalent.

However, as shown in Figure 3, 11 is an adder, 12 is a gain element 1y is an automatic control system, and in the automatic control system y, 9
6 indicates an adder, 97 a subtractor, and 98 a forward transfer function.

Here, if (k=o), the gain of the gain element 12 becomes zero, and the system is separated at this portion. Therefore, the target value R(8) and the control amount 0(S) are the control device 10,
10', the adder 7, and the range of the gain element 8'.

In other words, it becomes as follows.

This means that α(S), H'(8) is G(S), H
(S), so Equation (2')
The relationship is almost the same as Equation (1) without disturbance D(S), and [1/G'(8)), H'(S) is a control device, and due to parameter fluctuations of the controlled object, G(S) ) changes, the relationship in equation (2') remains unchanged and is not affected by this at all.

Note that (k = o) is an ideal state, but even if it is not zero, the influence of fluctuations and disturbances can be reduced by k (k < 1), and it is quite effective. . (k=
0) is actually equivalent to making the gain of gain element 8 shown in Figure 1 infinite, so although it is difficult strictly speaking, it can be achieved approximately using relay elements and integrators. can do.

〔effect〕

As explained above, according to the present invention, in contrast to the widely used conventional automatic control system shown in FIG. 4, two gain elements and two gain elements are used as shown in FIG. By adding a control device and one subtractor, the target value R
(8) and a control amount of 0 (S), it is possible to provide an automatic control system that can configure a control system that is less susceptible to parameter fluctuations and disturbances of the controlled object. In particular, in the case of servomechanisms, it is possible to obtain constant response characteristics even if the mechanical characteristics of the load change, which has an extremely large practical effect.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of the main part configuration to which the present invention is applied;
Figures 2 (a) and (b) are diagrams shown to explain the method of reversing the direction of the signal in Figure 1, Figure 3 is an equivalent diagram shown to explain Figure 1, and Figure 4 is FIG. 2 is a system diagram showing the configuration of a conventional closed-loop automatic control system for birds.几(S)...Target value, 0(S)...Controlled amount, D(S)...Disturbance, 3...Forward transfer function, 4・・・・・・Transfer function, 5・・・・・・
Feedback transfer function, 8.8', 12...
Gain element, older brother, y... Automatic control system, 10
, 10'...control device.

Claims (1)

[Claims] In an automatic control system that forms a closed-loop automatic control system consisting of a forward transfer function [G(S)] and a feedback transfer function [H(S)], a constant [k (0≦k ≦
1)], a gain element of (1/k) is inserted, a new feedback loop is provided, and the feedback loop is connected to a simulating element of the transfer function [G'(
S), H'(S)] and [1/G'(S)] and [H'
(S)] and (1-k
), and is characterized by making the constant (k) sufficiently small.