IMC based PI/PID controller tuning rule for time delay processes

The motivation of this study is to obtain single PI/PID tuning formula for different type of processes with enhanced disturbance rejection performance. A simple tuning formula gives the consistently better performance as compared to well-known SIMC method at the same degree of robustness for stable and integrating process. The performance of the unstable process has been compared with other recently published method which also shows significant advantage in the proposed method. For the selection of the closed-loop time constant, (t_c), a guideline is provided over a broad range of time-delay/time-constant ratios on the basis of the peak of maximum uncertainty (M_s). Comparison of the IAE has been conducted for wide range of θ/t ratio for the first order time delay process. The proposed method gives better performances for wide range of θ/t ratio as compared to SIMC while Lee et al. shows poor disturbance rejection in lag dominant process.