SU744453A1 - Variable-structure system - Google Patents

Description

one

The proposed system relates to automation and can be applied in the management of dynamic objects.

The closest in technical essence to the invention is system 1, comprising a key, a measuring unit, an initial conditions setting unit, a control and synchronization unit and serially connected logic unit, a coefficient switch and an execution unit, the output of which is connected to the input of the measuring unit through the control object the output of the coefficients associated with the second input of the switch.

A disadvantage of the known system is its low accuracy.

The purpose of the invention is to increase the accuracy of the system.

To do this, it contains functional calculation blocks, control object models and controller models, with the output of the measuring unit connected to the control object models through serially connected initial conditions block and a key, the outputs of which are connected to their second inputs through the corresponding controller models, and through the corresponding functional calculating units - with the inputs of the logic unit, and the output of the control and synchronization unit is connected to the second key input.

The drawing shows a block diagram of a variable structure control device. The following designations are made here:

5 1 - control object, 2 - measuring unit, 3 - coefficient switch, 4 - executive unit, 5 - initial conditions setting unit, 6 - key, 7 - control and synchronization unit, 8 - object model, 9 - controller model, 10 is a functional computing unit, 11 is a logical block.

The control device operates as follows.

15 The phase coordinates of the control object 1 are measured and compared with the set values of the phase coordinates Xs in the measuring unit 2. The error signal generated in the measuring unit 2,

20 enters the switch 3 factors. In it, the error signals on the phase coordinates are multiplied by the corresponding coefficients and summed, realizing the control law of the controller

25

,

where and is the control action; 30Xg - phase coordinates;

ki are the corresponding coefficients.

The coefficients ki can change in steps (change of structure), thereby implementing the law of control of one or another controller. The output of the switch 3 of the coefficients is connected to the input of the execution unit 4, which directly controls the object. To control the switching of the coefficients, by means of the block 5, setting the initial conditions and the closed key 6, controlled by the control and synchronization block 7, we set the initial conditions on the object model 8, operating in an accelerated time scale in the prediction mode. After that, the key 6 is opened, the predictive models of the objects are switched to the decision mode, while controlling each corresponding model 9 of the controller. As models of regulators, all variants of control laws that can be implemented by a block of switched coefficients are used.

In the time interval from the beginning of the decision to the end of the transition process in the model of the object controlled by the model of the controller, block 10 calculates a certain functional over which the optimization is carried out. After the end of the transition process in the last object model, logic block 11 compares the values of the functionals at the outputs of the functional calculation blocks 10 and performs the switching of the coefficients in the coefficient switching unit so as to realize the control law of the controller of the object model corresponding to the minimum of the functional. After that, the cycle repeats. Thus, a comparison is made of all control laws that can be implemented by a block of switched coefficients, and the control law is chosen to control the object, with which the minimum of a given functionality is provided for the object model.

As a functional, the integral of the square of the error during the transient process or the time of the transient process (maximum speed) can be used. The end of the transition process can be determined by the input of the transition process in a 5% “tube. The cycle time should be chosen as short as possible. The control and synchronization unit must ensure that the models work in the initial conditions setting mode (the key is closed) and in the decision mode (the key is open). In the simplest case, the unit can be implemented on a multivibrator and work on a rigid program. Relays can be used as keys. For the functional unit for calculating, for a minimum of the root-mean-square error, for example, a quadrant and integrator connected in series can be used, and as a model for the object and the regulator, circuits assembled on LS chains and operational amplifiers. The only requirement for controller models and regulators implemented by the coefficient switching unit is the stability of the object controlled by this controller (similarly to the controller and object model). Laws of control regulators implemented

0, by the switching unit of coefficients, are selected similarly to the prototype.

The logical block can be implemented in the simplest case (in the block of switched coefficients only

5 two laws of control are analogous to the block forming the function of switching the prototype with the only difference that instead of function 5 the function / i- / a is used, where / 1 is the value of the functional provided by the first implemented control law (controller), / 2 is the value of the functional provided by the second law of governance.

The use of new elements - predictive models, functional calculation blocks, logic block favorably distinguishes the proposed variable structure control device from the prototype, as it allows to optimize the system

control by specified criteria. This makes it possible to improve the quality of the control system, to obtain a transition process that is close to optimal.

Claims (1)

Invention Formula A variable structure system comprising a key, a measuring unit, an initial conditions setting unit, a control and synchronization unit and serially connected logical unit, a coefficient switch and an execution unit, the output of which is connected to the input of the measuring unit through the control object and connected to the second input of the switch coefficients, characterized in that, in order to increase the accuracy of the system, it contains blocks for calculating the functional, control object models and controller models, and the output the measuring unit through serially connected unit sets the initial conditions and the key is connected to the inputs of the control object models, the outputs of which are connected to their second inputs through the corresponding controller models, and the output of the control unit and synchronization are connected through the corresponding functional calculating blocks with the second key entry. 0Sources of information taken into account during the examination 1. S. Emelnov. Automatic control systems with variable structure, M., 1967, p. 304-305 (prototype).