Research On Sliding Mode Control Of Several Classes Of Neutral Systems

The research of SMC for neutral systems is an important direction in modern control theory.Neutral systems are a class of generalized time-delay systems,in which the state of the system is not only related to the state of the past time,but also to the change rate of the state of the past time.Neutral systems have a wider application background.Most time-delay systems can be regarded as special cases of neutral systems,and many time-delay systems can also be transformed into neutral systems.SMC is a kind of discontinuous controls which breaks through the fixed structure,and its control law is simple and does not need accurate system model.The most important thing is that the system has complete robustness to external disturbances and unmodeled dynamics when it is in sliding mode.Therefore,the study of SMC of neutral systems has important practical value and theoretical significance.In this thesis,the SMC of several classes of neutral systems is studied,including the theory of chattering suppression,control law design,sliding mode function design and observer.The following main innovations and research contents are given:(1)The problem of chattering suppression for sliding mode control of neutral systems with mismatched disturbances is studied.Firstly,the main consideration is to suppress chattering by perturbation,a disturbance observer for neutral systems with mismatched disturbances is established firstly,and the controller is constructed by observing the disturbance values,so that the system state reaches the sliding surface in finite time,and a sufficient condition for the stability is obtained during the time of sliding.Finally,the simulation results show that the disturbance has a good effect on chattering suppression.(2)The sliding mode control of uncertain neutral systems with Markov jump is studied.Firstly,a controller is designed to enable the system to reach the sliding surface.Considering the introduction of neutral operators into the design of sliding mode functions,and a stability theorem is proposed-Secondly,due to external disturbances,a non-fragile H? observer is introduced when the state is not measurable,and then sliding mode control is applied to the error system.Finally,the validity of the theorem is verified by simulation.(3)The sliding mode control of uncertain neutral stochastic system with Markov jump and partial unknown transition probability is studied.Based on the research results of sliding mode control for uncertain neutral systems with Markov jump,Markov jump systems with partial unknown transition probability are considered.Firstly,a sliding mode control law is designed to enable the system state to reach the sliding mode surface in finite time,and a sufficient condition that the system state slide to the stable equilibrium point on the sliding mode surface is proposed.Finally,a numerical example is given to illustrate the correctness of the proposed results.