H-infinity controller design for pneumatic servosystem: a comparative study

In recent times, pneumatic servosystems have received wide acceptance in industries and other special systems. Current researches focus on improving the disturbance rejection properties of pneumatic servosystems to work well in industrial environment. So far many controllers have been developed to control the system, of which the H-infinity controller is found to guarantee robustness and performance. In this paper, design of robust H infinity controller is proposed for pneumatic servo system using different techniques such as mixed sensitivity function, loop shaping design using Glover-McFarlane method and optimal controller design based on solution of Riccati equations and comparative analysis is done with conventional PID controller tuned using Ziegler-Nichols method. Comparison with a well tuned PID controller shows the efficacy of H-infinity controller designed using the proposed algorithms.