A novel mechanism for autotuning based on quantisation

Abstract Relay auto tuning has found wide acceptance in industry. However, the method suffers from several disadvantages, especially the need to remove the existing controller, which is replaced by a relay. This paper describes a new approach aimed at retaining the substantial advantages of the relay autotuning method whilst minimising the associated disadvantages. In particular, it is proposed that a quantiser be used at the controller output. This can be thought of as multiple relays that automatically sustain the operating point. It is also shown how multiple frequency points can be examined and how the existing controller can be simultaneously estimated together with the plant.