An Optimization Procedure based on Analytic Stability Conditions for Systems Linearized by the Describing Function Method

There are limitations to the analytical methods which may be used to select the optimum parameters of a control system using iterative optimization techniques. These methods tend to optimize systems only with respect to certain types of performance criteria and only for a limited class of input signals. Present iterative optimization methods are unable to handle directly the analytical stability conditions for systems linearized by the describing function method. A method of incorporating these stability conditions into the many optimization procedures which use the gradients of stability constraints is shown, and an example of its use in the design of a compensator in a nonlinear control system is also presented. © 1982 Butterworth & Co. (Publishers) Ltd.