Optimal PID Tuning for Second Order plus Dead Time Processes

Using dimensional analysis and numerical optimisation techniques, an optimal PID tuning method for second order plus dead time processes is proposed. Considering a step change in setpoint, PID tuning formulae are developed through minimising an objective function. To consider robustness issues, the optimisation problem is constrained so that a minimum gain margin of 3 and a minimum phase margin of 60° are guaranteed. Simulation results show that the proposed tuning formulae are effectively applicable to a large variety of processes.

Keywords:

PID control , SOPDT process , NDT technique