Automated design of multivariable control systems

A new automated procedure for the computer-aided design of linear, time-invariant, multivariable control systems is developed for the case where the design specifications are given in the frequency domain in the form of stability margins, loop gains, and closed-loop frequency responses. The procedure minimizes a cost (penalty) function which measures the deviation of the system responses from those specified to obtain the required fixed-configuration compensation to meet the specifications. The procedure is applied to a representative aircraft control system design problem using three local search techniques (optimium step-size gradient, Fletcher-Powell, and Rosenbrock pattern search) and a new "global" random search technique for the required minimizations. The new "global" random search technique appears to be superior to the local search techniques for the class of problems studied.