The Next Generation of Relay-Based PID Autotuners (PART 1): Some Insights on the Performance of Simple Relay-Based PID Autotuners

The paper presents theoretical insights which might lead to further development of improved relay-based PID autotuners. The analysis is based on the first generation of autotuners, namely the widely used Åström-Hägglund relay-feedback tuner. The analysis is accompanied by illustrative examples. The performance of the autotuners is evaluated against a reference PID controller which is designed using computer aided design tools and assuming full knowledge of the system's transfer function. The paper is concluded by pointing towards some ideas to design a more generally valid version of the PID autotuner.