Simple fuzzy PID controller tuning of integrating process with dead-time

Integrating process with dead-time is commonly encountered in process industry. Integrating process can usually be approximated by a low-order plus time-delay model. In this paper, a simple fuzzy proportional-integral-derivative (PID) controller tuning method is proposed for a generalized second-order integrating process with dead-time, which is based on matching the coefficients of corresponding powers of s in the numerator and that in the denominator of a closed-loop system. A simple tuning parameter for PID controller is obtained. A new exponential term approximation is introduced which can reduce the model error. The proof shows that the system performance can be guaranteed. The fuzzy rule base is built and fuzzy tuning of the obtained tuning parameter is applied. The result of the fuzzy tuning method is compared with that proposed in literature under both time varying and non-varying condition. The proposed simple fuzzy tuning method shows a better time domain performance and good robustness under time varying condition.