ERROR TRAJECTORY DESCRIPTIONS OF NONLINEAR CONTROLLER DESIGNS

Research in nonlinear process control is rapidly expanding with an increasing number of seemingly diverse control algorithms appearing. In this review an alternate method of formulating nonlinear control laws is presented. This formulation, which uses the concept of a tracking error trajectory in a differential geometric setting, provides a framework for direct comparison of a number of recently proposed nonlinear process controllers. In addition, the inclusion of integral action in nonlinear control laws can be motivated in terms of the estimation of an output disturbance. Finally, a more general approach to nonlinear controller design is suggested. © 1990.