An analytic method for finding the closed-loop frequency response of nonlinear feedback-control systems

THE linear theory in the field of feedback-control systems is highly developed and various techniques are available for analysis and synthesis of linear feedback-control systems. On the other hand, there are many problems to be solved in the field of nonlinear feedback-control systems. Techniques of analyzing and synthesizing nonlinear feedback-control systems are quite limited because of difficulties in handling nonlinear differential equations.