Fractional control of precision modular servo setup for better limit cycle suppression

In this paper, we report an interesting superiority of fractional order controllers over conventional order controllers. It is found that the fractional order proportional-integral controllers (PI^α and [PI]^α) designed for precision modular servo experimental setup to meet given loop shaping requirements outperform the correspondingly designed integer order PID in limit cycle suppression. More precisely, a pretty significant reduction in the limit cycle amplitude is observed with PI^α and [PI]^α as compared to the normal (integer order) PID in the real time closed loop system response.