Servo Design for Nonlinear Systems with Output Feedback

A new servo design methodology for nonlinear systems will be presented. This methodology provides a systematic procedure to solve the output tracking problem in the absence of full state variable feedback, while addressing the issues of closed loop stability, performance and robustness. This nonlinear servo design procedure combines techniques from Input/Output Linearization and Nonlinear Model Based Compensation-Loop Operator Recovery. It achieves improved performance and enhanced robustness properties with respect to the control techniques involved in its assembly, without increasing the magnitude of the control signals. Simulation results show that with appropriate filtering, for Input/Output Linearization based control schemes, dynamic compensation provides better performance than static compensation. Performance improvement is achieved by means of approximate disturbance cancelation, using a disturbance model derived from new results on Loop Operator Recovery.