Improving Control Behaviour with Set-Point Pre-Processors

The design principle of control algorithms working with set-point pre-processors, called SPP controllers, is described. Set-point pre-processors calculate internal set-point graphs of controlled variables in such a way that very high controller gains are attainable and, thus, stability is increased. The behaviour of SPP controllers is normally much closer to the “best physically possible” controller performance, and much more predictable than the one of conventional control structures. Furthermore, otherwise conflicting design objectives can nearly all be achieved, e.g., stability, safety, high speed, small energy consumption, or steady and harmonic temporal controller output values. Since SPP control algorithms allow for extremely fast reactions, it was obvious to approximate their mathematical models by rule base tables allowing their implementation by safety licensable fuzzy controllers.