Self-tuning PID control structures

There has been much work on self-tuning PID controllers. There are many possible structures for PID controllers. The basic concepts of PID control can be generalised within the same structure but allowing for the control of complicated dynamic systems using advanced control design algorithms. This structure arises naturally from the system description and does not need to be imposed artificially. The concept of PID control can be usefully generalised to make contact with recent methods such as internal-model control and generalised predictive control. One should not start with a PID controller and then decide how to tune it, but rather one should start with a rational design method and system model from which a (generalised) PID structure will then materialise. Recent advances in local model networks using multiple-model self-tuning PID controllers give a neat extension of the basic (generalised) PID structure to handle nonlinear or time-varying systems. The PID concept is alive and well