PID autotuner based on gain- and phase-margin specifications

In this paper, a simple and efficient PID autotuner is proposed. First, a second-order plus deadtime model is identified on the basis of two continuous relay feedback experiments. With the model available, the PID controller is designed on the basis of gain- and phase-margin specifications. The PID autotuner achieves high performance for processes with various dynamics, including those with low- and high-order, small and large dead-time, and monotonic and oscillatory responses. Simulation examples show the effectiveness and flexibility of the PID autotuner.