A comparative performance study of PID auto-tuners

The benchmark testing of the autotuning performance characteristics of three controllers is reported. The controllers are two commercial single-loop proportional integral-derivative (PID) controllers, the SattControl relay feedback autotuner and the Foxboro EXACT self-tuning controller, and a refined Ziegler-Nichols prototype PID controller autotuned by means of the cross-correlation method. A novel microcontroller-based process simulator has been used to simulate several generic processes for the benchmark tests. Quantitative results based on the integral squared error of the transient responses are used to contrast the relative performance of the autotuning controllers in the presence of setpoint change, static load disturbance, and measurement noise. Another performance measure, namely the retuning time, is used to compare performance.<<ETX>>