Research And Application Of Robust Control Method For Uncertain Systems

Based on the development demand of national defense technology and control theory,the research on uncertain systems has attracted wide attention.The research direction of uncertain systems is many and involves many aspects.This paper mainly focuses on the research of control methods for uncertain systems.At present,the methods of disturbance compensation control,sliding mode control and adaptive control have been studied and widely used because of their good robust performance to the uncertain system.However,there are still many deficiencies in the research of these control methods.First,there is a control peak problem that may be caused by the estimated peak in the disturbance compensation control;secondly,most of the control methods can not suppress the unmatched uncertain disturbance;finally,the research on the control gain unknown system is less.The problems solved in this paper and the innovation points are as follows:In this paper,a series of researches on the problem of peaking-free observer-based control methods are proposed.First,we study the existing reduced order disturbance observer and the occurrence condition and time of the estimated peak phenomenon of the extended state disturbance observer.Then,two solutions are proposed to solve the peak ing problem,namely,the scheme of designing time-varying observation gain and the scheme of blocking the peak.These two estimation peaks are the foundation of the following no spike disturbance compensation control.Then,in this chapter,two novel time-varying gain disturbance observers(time-varying gain observers and adaptive gain finite time convergence disturbance observers)are designed for the scheme of time-varying gain design.A series of researches are carried out on the sliding mode control of uncertain systems with no-peaking compensation.Based on the time-varying gain disturbance observer,the adaptive disturbance observer and the traditional sliding mode control are combined to solve the peaking problem,a non-peaking compensation sliding mode control algorithm is proposed.In addition,in order to further improve the robustness and rapidity of sliding mode control,a new nonsingular sliding mode with specified time convergence is proposed.Based on the proposed adaptive disturbance observer and the new sliding mode,a finite time convergent sliding mode controller with no peak disturbance compensation is designed.For a class of non-affine and non-matching uncertain systems,A series of studies are carried out.In order to solve the problem of non-affine nonlinear and non-matched disturbance,the system is transformed into a matching uncertain system with unknown intermediate state based on differential.Then,the unknown intermediate state and the matched disturbance are simultaneously estimated based on the high-order extended state observer.Then,based on the output of the high-order extended state observer,the sliding mode surface is constructed,and then the corresponding disturbance compensation sliding mode controller is designed.Then,in order to solve the potential peak problem of the high order extended state observer,the blocking peak factor is added to the sliding mode surface,and a non-peaking compensation sliding mode controller is designed.For a class of uncertain matching systems with unknown control inputs,a series of researches are carried out based on adaptive sliding mode control.Firstly,an adaptive sliding mode controller is proposed for uncertain systems with unknown control gain but known positive and negative control gain.The proposed control scheme effectively guarantees the convergence of the system state.Then,based on the adaptive sliding mode controller,the control direction switching decision strategy is added to the uncertain system with unknown control gain and positive and negative gain.The control gain size and the negative impact of positive and negative uncertainty are eliminated.Then,in view of the fact that the proposed direct handover strategy may be difficult to respond to the actual controller,a transition strategy of switching control direction is proposed.For a class of unmatched uncertain systems with unknown control inputs,a series of researches are carried out based on adaptive sliding mode control.Firstly,based on differential and compensation,the unmatched uncertain system is transformed into a matc hing uncertain system with unknown intermediate state.Then,the high order extended state observer is designed to estimate the unknown intermediate state.Then,the sliding surface is constructed based on the output of the system state and the high order extended state observer,and the peak factor is added to the constructed sliding surface in order to solve the estimated peak phenomenon that the observer may appear.Then,based on the adaptive method,the control law is designed to ensure that the output state of the control system converges to the zero area for the unknown control gain but the positive and negative.Then,for the control gain size and the positive or negative conditions are unknown,on the basis of the adaptive method,the switching method is added to ensure the stable convergence of the output state.At the same time,aiming at the problem that the direct controller can not respond to the actual controller,the switching method is designed by using the transition handover mode.Simulation results verify the effectiveness of the proposed control scheme.Finally,a variety of theoretical research results are applied to a series of guidance and control problems for near space interceptors.Aiming at the design problem of interceptor guidance law,a sliding mode guidance law without spike interference compensation is designed.For the integrated guidance and control design of interceptor with unmatched uncertain disturbance,a jamming compensation sliding mode controller based on blocking peak factor is proposed.Aiming at the attitude control problem of the Kinetic Energy Interceptor with unknown control gain,a switching direction controller based on adaptive sliding mode control is proposed.