Event-triggered Adaptive Fuzzy Control For Nonlinear Systems

In the real physical and engineering systems,there are many problems,such as nonlinear term,random disturbance,uncertainty,dynamic mutation and comprehensive control.The existence of these problems will not only greatly reduce the performance index of the system,but also cause the error and oscillation of the system,which will directly affect the stability of the system.Therefore,the research and design of the control scheme of the system with nonlinear input has inestimable practical significance.In the study of the actual system,there is a certain degree of constraints.We have to formulate a corresponding control scheme in order to achieve the preset performance of the system,so that the state and output of the system can be limited within the constraints.In the third chapter,we design the adaptive fuzzy control for a class of stochastic nonlinear systems with input saturation characteristics based on the event-triggered mechanism.In order to overcome the design difficulties caused by saturation nonlinearity,the saturation function is approximated by introducing a method of controlling the smooth nonlinear function of the input signal.Secondly,an adaptive fuzzy tracking controller based on the median theorem is constructed using Backstepping technology.On the basis of the above,in order to save the communication resources of the system,this paper introduces an event-triggered control mechanism based on a relative threshold strategy to reduce the transmission pressure of the system.Furthermore,the proposed adaptive fuzzy controller ensures that all signals in the closed-loop system are bounded in probability through the analysis of Lyapunov stability theory,and the output of the system finally converges to the small neighborhood of the desired reference signal in the sense of the average fourth power.Finally,the accuracy and effectiveness of the proposed control scheme are further verified by giving the simulation examples.In the fourth chapter,we design an adaptive fuzzy tracking control scheme for a class of time-delay nonlinear systems with input dead zone and full-state constraints based on an improved event trigger mechanism.In this paper,we construct appropriate Lyapunov function to compensate for the delay,and ensure that all states of closed-loop system do not violate the predefined compact set.In this paper,the fuzzy logic system is used to approximate the nonlinear function.Further,the design and analysis method of the improved adaptive event-triggered control strategy is adopted to realize a control scheme with fixed threshold,event-triggered control input and tracking error decreasing function,which effectively reduces the computational burden of the communication process.Finally,the proposed controller in this paper guarantees that the closed-loop signals are locally uniformly bounded,the system states_ix(t)can be constrained in the appropriate compact set?_{x i},and the error tracking signals will converge to the appropriate compact set?_ei.At the same time,this scheme also avoids the Zeno behavior.The simulation results show that the scheme is effective.