Design of a H-infinity robust controller for a DC servo motor system

This paper presents a mixed sensitivity based design approach of H-infinity controller for a dc servo motor system. Frequency dependent suitable weight functions for sensitivity and complementary sensitivity transfer functionare chosen to design the controller. Synthesis of H-infinity controller is performedusing Robust Control Toolbox in MATLAB. The input output data samplesfor a laboratory based DC servomotor system are takenover a finite duration of time. The SystemIdentification Toolbox in MATLAB has been employed to obtain the plant model from the input output dataset. Fitness of the model is investigated by applying different dataset in order to achieve the best fit model. Time domain performance of the system has been observed to illustrate the effectiveness of the designed controller.