Some advantages of the autotuning approach in PID control

The normal approaches to control system compensator design in both classical and modern control first require one to obtain a mathematical model of the process. This is also usually the case even when the form of compensator has been decided and only its parameters need to be found or tuned. This procedure suffers from two disadvantages, firstly the need to find a mathematical model which may be time consuming and not necessarily straightforward, and secondly if tuning in situ is required because the model is poor or its parameters change with time further modelling has to be done or some other approach has to be used. In this paper the theory of the autotuning method is presented and this is followed with a simple example which illustrates the robustness of frequency response tuning. The paper discusses PID tuning algorithms and briefly outlines additional facets of autotuning. Finally some conclusions are given