Optimum Analytical Tuning of I-PD Controllers for Unstable Time Delay Systems

Unstable processes are frequently encountered in industrial applications. Proportional-Integral-Derivative (PID) controllers are the most widespread used controllers for controlling unstable processes. However, it has been shown that PID controllers perform unsatisfactorily for controlling unstable processes. Therefore, this study reports on the use of I-PD controllers for improving closed loop performances of unstable processes. Optimal and analytical tuning rules have been derived to calculate tuning parameters of the I-PD controller. Simulation results, giving comparisons of some existing PID and I-PD design methods to control open loop unstable processes, have been supplied to illustrate superior closed loop performance of the proposed optimal and analytical I-PD design approach.