A Comparison of Several Controllers for Plants with Saturating Power Amplifiers

This paper analyzes the behavior of several control algorithm when used for a plant with saturating power-amplifiers. This analysis is mainly done by experiments using a typical DC-servo configuration. It is shown that linear feedback controllers can produce a significantly degraded closed-loop behavior in the presence of saturations of the power-amplifiers. For plants having saturated power-amplifiers the behavior of several well-known controllers is compared in this paper. In addition a heuristic nonlinear extension of the classical state-feedback controller is proposed which is shown to produce much better transients than its linear counterpart. Finally some key questions are identified which will have to be answered by further research efforts.