Anti-disturbance Control For Systems With Multiple Disturbances

Disturbances exist widely in practical applications and affect the performance of the controlled system.Because of the increasing complexity of the controlled object and environment,and the increasingly high requirements for control accuracy,real-time performance and stability,the rejection and stabilization of disturbances has become a research hotspot in recent years.Under the background,the anti-disturbance control problelms are considered for a few classes of systems with multiple disturbances by using the conrtrol?DOBC?method.The main content includes the following three aspects:Firstly,the anti-disturbance control problem is studied for a class of discrete-time stochastic systems with multiple disturbances.Multiple disturbances are divided into three parts:the non-harmonic disturbance,process disturbance in theH₂-norm and a sequence of random vectors.A nonlinear disturbance observer?NDO?is constructed to online estimate non-harmonic disturbances,on this basis,by combiningH_?control and DOBC method,a nonlinear disturbance observer-based control?NDOBC?scheme is proposed.This proposed strategy make the composite system achieves asymptotically mean-square bounded and asymptotically mean-square stable in the different conditions.Secondly,the problem of finite-time anti-disturbance control is considered for a class of system with multiple disturbances.Multiple disturbances are divided into two parts:the disturbance with partially-known information and the perturbations of uncertainties.This chapter extends the current DOBC work into the finite-time control method.By designing a disturbance observer?DO?to online estimate disturbances and a disturbance observer-based finite-time control?DOBFTC?scheme is proposed by combining with Implicitly Lyapunov function method.This scheme can make the composite system ensure its robust performance and achieve globally finite-time stable,and the convergence time can be adjusted by the initial value and the controller parameter.Thirdly,the fixed-time anti-disturbance control problem is investigated for a class of system under multiple disturbances.In this part,by combining the fixed-time control method with the anti-interference control,the disturbance observer?DO?is constructed to estimate the disturbance online and the Implicit Lyapunov function method is combined to propose the fixed-time anti-disturbance control?FTADC?scheme.The scheme can guarantee the globally fixed-time stable of the system state and the convergence time is independent of the initial value.