Indirect adaptive fuzzy sliding mode control method of SISO discrete time system

Abstract

An indirect adaptive fuzzy sliding mode control method of a SISO discrete time system is disclosed. The method comprises the following steps: step 1. selecting an offline parameter; step 2. constructing a sliding mode controller with a fuzzy subsystem; step 3. performing online adjustment to a parameter vector of a fuzzy system and calculating control input. An adaptive law with parameter projection is used to on-line adjust the parameter vector of the fuzzy system. According to the invention, through introducing the sliding mode control, system uncertainty, an adverse effect of unknown external interference on system stability and dynamic performance can be overcome. Through introducing a unknown function and switching control in the fuzzy system approximation sliding mode control law of the parameter vector adaption adjustment, dependence of a control method to a system prior model can be eliminated, flutter caused by the switching control can be mitigated and even completely eliminated and precision for system output to track a given track can be increased. By using the method of the invention, the system stability and the dynamic performance can be simultaneously considered and practical value is possessed.

Description

technical field [0001] The invention relates to the technical field of sliding mode variable structure control, in particular to an indirect self-adaptive fuzzy sliding mode control method for a single-input and single-output discrete-time system whose model is unknown and has external interference. Can have a wide range of applications. Background technique [0002] In the control of a single-input-single-output (SISO) discrete-time system with an unknown model, after searching the prior art, it was found that in the literature Indirect adaptive fuzzy control for a class of nonlinear discrete-time systems (Journal of Systems Engineering and Electronics, 2008, 19(6): 1203-1207.), the author proposed an indirect adaptive fuzzy control method (IAFC), which achieved good results in the absence of external disturbances in the system; in the literature Robust adaptive quasi-sliding mode controller for discrete-time systems (Systems and Control Letters, 1998, 35(3): 165-173.), th...

AI Technical Summary

Problems solved by technology

For the case of a large sampling period, it is difficult to directly discretize the continuous control method to ensure the stability and control effect of the system

Due to the influence of the environment in which the actual system is located, the existence of interference will also have an adverse effect on the control effect

The IAFC control method proposed in the literature Indirect adaptive fuzzy control for a class of nonlinear discrete-time systems (Journal of Systems Engineering and Electronics, 2008, 19(6): 1203-1207.) does not consider external disturbances, and cannot guarantee the existence of disturbances case, the stability and dynamic performance of the system

The RAQSMC control method in the document Robust adaptive quasi-sliding mode controller for discrete-time systems (Systems and Control Letters, 1998, 35(3): 165-173.) is also due to its availability and expression form of the estimated model limited and difficult to apply to model-unknown systems

Literature Sliding mode control of a discrete system (Systems and Control Letters, 1990, 14 (2): 145-152.) and Discrete-time variable structure control systems (IEEE Transactions on Industrial Electronics, 1995, 42 (2): 117- The discrete sliding mode control method proposed in 122.) can well overcome system uncertainty and external disturbances, but both require pre-obtained bounds of the estimated model and disturbances, and direct switching control will lead to severe chattering , making the control law designed by this method difficult to apply in the actual system

Images