PID Controller Design Based on the Time Domain Information of Robust IMC Controller Using Maximum Sensitivity

The IMC (Internal Model Control) controller based on robust tuning can improve the robustness and dynamic performance of the system. In this paper, the robustness degree of the control system is investigated based on Maximum Sensitivity (Ms) in depth. And the analytical relationship is obtained between the robustness specification and controller parameters, which gives a clear design criterion to robust IMC controller. Moreover, a novel and simple IMC-PID (Proportional-Integral-Derivative) tuning method is proposed by converting the IMC controller to PID form in terms of the time domain rather than the frequency domain adopted in some conventional IMC-based methods. Hence, the presented IMC-PID gives a good performance with a specific robustness degree. The new IMC-PID method is compared with other classical IMC-PID rules, showing the flexibility and feasibility for a wide range of plants.