Order reduction and decoupling method of industrial control system

Abstract

The invention discloses an order reduction and decoupling method of an industrial control system. The industrial control system comprises a plurality of subsystems. The method comprises the following steps: A) establishing a nonlinear state space model of the industrial control system, wherein the nonlinear state space model comprises actuator dynamic which is coupled with the subsystems; B) designing expected closed-loop dynamic of the each reduced-order subsystem; C) selecting a sliding mode plane according to the expected closed-loop dynamic; D) designing a sliding mode controller so that the subsystems possess the expected closed-loop dynamic on the sliding mode plane, decoupling between the subsystems can be realized and the subsystems can guarantee to converge to the sliding mode plane in a limited time under the condition of errors caused by the actuator dynamic; E) using a saturation function which is similar to a switch function in the sliding mode controller, adjusting a keyparameter so as to optimize closed-loop system performance. By using the method of the invention, system order can be reduced; the design of the controller can be simplified and the closed-loop system performance can be optimized.

Description

technical field [0001] The invention relates to a method in the technical field of industrial control, in particular to an order reduction and decoupling method for an industrial control system based on sliding mode technology. Background technique [0002] The actual industrial control system is usually composed of multiple interconnected subsystems. Each subsystem is generally composed of two parts: the actuator and the object. The control system adjusts the reference input of the actuator according to the deviation between the object output and the set value, so as to achieve The purpose of the control object output. The traditional PID controller often used in the actual industrial control system usually distributes the control of each subsystem and does not consider the dynamics of the actuator. This control scheme has the following two problems: [0003] (1) Cannot handle actuator dynamics. Actuators in actual industrial systems, such as hydraulic equipment, electri...

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Problems solved by technology

[0003] (1) Unable to handle executor dynamics

Actuators in actual industrial systems, such as hydraulic equipment, electrical equipment, etc., usually have complex inner-loop control systems to ensure their fast response and high accuracy, but due to the non-ideal characteristics of devices, actuators usually have time delays , hysteresis, dead zone, etc.

If this dynamic is not considered in the design of the control system, the performance of the control system will be deteriorated

But on the other hand, if the equations are written for each actuator, and then the controller is designed, the dimension of the system will be greatly increased, and the difficulty of controller design will be doubled

[0004] (2) Unable to handle coupling between subsystems

Usually, there are various couplings among the subsystems of the actual industrial system. If these couplings are not dealt with, the accuracy of the closed-loop control system will be affected.

But on the other hand, these couplings often have a simple and direct structure, and the use of a systematic decoupling control method will lose the flexibility of the controller design

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