Research On Sliding Mode Predictive Fault Tolerant Control For Uncertain Discrete Time Systems With Time Delay

The control system is developing towards the direction of large-scale and complexity.This system has the characteristics of high degree of digitization,inaccurate model,accompanied by disturbance and easily happened faults.Therefore,it is necessary to study the fault-tolerant control methods for such discrete systems.Time delay is very common in practical systems. This increases the design difficulty of fault tolerant control algorithm.It results in the final controller can not make the closed-loop system have the desired dynamic performance,thereby reducing the actual control effect,and even cause the system is not stable.This paper studies the fault tolerant control method of sliding mode predictive control for uncertain discrete systems with time-delay,combined with the sliding mode control(SMC)and model predictive control(MPC).This research mainly includes the following contents.1.The robust fault tolerant control of a class of uncertain discrete-time systems with time delay under actuator faults is studied.This system includes state varying time delay,parameter perturbations and external disturbance.A sliding mode predictive fault tolerant control based on Multi-agent particle swarm optimization(MAPSO)is presented.Firstly,the sliding mode prediction model of the system is designed by assigning poles of the output error of the system,and a new discrete reference trajectory is proposed.Secondly,the traditional receding-horizon optimization is improved by PSO.Thirdly,experimental results of quad-rotor helicopter simulation platform prove the feasibility and effectiveness of the proposed control scheme.2.For the above system,a kind of sliding mode fault tolerant predictive control based on self-adjusting chaos particle swarm optimization(SCPSO)is proposed.Firstly,a quasi-integral sliding mode prediction model is constructed.Based on the Lyapunov stability theory and linear matrix inequality technique,the sufficient condition of the asymptotic stability of the sliding mode prediction model is given.Secondly,compared to PSO used in the last point,the receding-horizon optimization is further improved by introducing chaos factor and accelerating convergence factor.Thirdly,the experimental results of the quad-rotor helicopter platform have the characteristics of fast response,small overshoot and small chattering.3.On the basis of the previous point,the problem of robust fault tolerant control is studied in the case of sensor faults for the system with state delay and input delay,and a sliding mode fault tolerant predictive control scheme based on multi-swarm cooperative chaos simulated annealing particle swarm optimization(MCCSAPSO)is proposed.Firstly,the equation of the sensor fault system with constraint is transformed into a new state equation.The sliding mode prediction model is constructed based on the new fault system state equations.Secondly,the receding-horizon optimization process is improved based on MCCSAPSO.Thirdly,the experimental results of the quad-rotor helicopter simulation platform show that the proposed controller has a good control proformance.