Design and experimental evaluation of robust PID and PI-PD temperature controllers for oil-cooling machines

This paper presents techniques and methodologies for design and experimental evaluation of both robust PID and PI-PD temperature controllers for oil cooling machine systems. The process of oil cooling machine can be experimentally described as a second-order model with time delay. A robust PID controller with sensitivity specifications is proposed to achieve set point tracking, disturbance rejection, and robustness against time-dependent parameter variations. With the obtained three-term parameters of the robust PID controller, a PI-PD controller is constructed in order to control more general industrial processes or plants. Computer simulations are performed to illustrate the superior performance and merit of the proposed PID and PI-PD controllers in comparison with conventional ones. The applicability and usefulness of the proposed control scheme are well exemplified by conducting experiments on a physical high-speed oil cooling machine. Both simulations and experimental results reveal that the proposed PID and PI-PD scheme outperforms the conventional PID and PI-PD controllers.