Robust Tracker Design Using Composite Nonlinear Feedback for Uncertain Dynamical Systems with Multiple Time Delays

Robust Tracker Design Using Composite Nonlinear Feedback for Uncertain Dynamical Systems with Multiple Time Delays

In this paper, the theory of using algebraic Riccati equation and composite nonlinear feedback technique is considered for robust tracking and model following of linearsystems with time-varying uncertain parameters, multiple timedelays and disturbances. It is guaranteed that with the designed controller, the tracking error decreases asymptotically to zero in the presence of time varying uncertain parameters, delays and disturbances. For performance improvement of the dynamicalsystem, the proposed robust tracking controller consists of linear and nonlinear feedback parts without any switchingelement. The linear feedback law is designed to allow the closed loop system have a small damping ratio and a quick response,while the nonlinear feedback law increases the damping ratio of the system as the system output approaches the output of the reference model. The simulation results illustrate the validity of the developed method