Analytical tuning rules of digital PID controllers for integrating processes via the Symmetrical Optimum criterion

Explicit tuning rules for digital PID regulators are presented regarding the control of integrating processes. Controller parameters are determined analytically as a function of the process parameters and the sampling time of the controller. The derivation of the proposed PID control law lies in the principle of the Symmetrical Optimum criterion. The performance of the proposed control law is compared with the conventional tuning of the PID regulator via the Symmetrical Optimum criterion when controlling the same process. Simulation examples show improvement of output disturbance rejection of up to 71.05% decrease of settling time.