Mixed Stabilization And H_? Control Of Uncertain Linear Systems With Input Constraint And Time Delay

Time-delay,uncertainty and input constraint are widespread in various systems.They can influence the performance especially the stability of a system,thus need paying cdose attention when designing a controller.On the other hand,it is often required that a control system have a logical transient process,a high-precision steady-state response and the property of strong robustness against the external disturbance.Therefore,aiming at a class of linear uncertain time-delay systems with input constraint,the study on the control synthesis under the compounded consideration of a better transient and steady performance and stronger robustness has a great significance in both theory and application.The main contents of this thesis include the following two aspects:First,sufficient conditions to guarantee the mixed stabilization of the linear uncertain time-delay system are given.The mixed stabilization problem is converted into the feasibility problem of some linear matrix inequalities?LMIs?.The effectiveness of the proposed control strategy is demonstrated through the numerical simulation of an unmanned aerial vehicle.Second,considering a linear uncertain time-delay system with an input constraint and an external disturbance,an H_? controller based on mixed stability is presented so that the closed-loop system is internally mixed-stable and the L₂-gain from the external disturbance to the controlled output is no greater than a given constant ?.Also the H_? control problem based on mixed stability is solved through the feasibility problem of some LMIs.