ON THE RESPONSE OF NON-LINEAR TIME-VARIANT CONTROL SYSTEMS SUBJECTED TO A PREASSIGNED SIGNAL IN THE PRESENCE OF GAUSSIAN RANDOM NOISE

A graphical method of evaluating the response of nonlinear time-variant control systems excited by a step input in the presence of a stationary random noise is presented. Descriptions theoretically treat various problems. First, in order to motivate the general procedure an extension of the phase plane method is carried out and the indicial response of nonlinear time-variant control systems under the disturbance-free condition is graphically calculated. Second, the non stationary response of nonlinear time-variant control systems with a random input is evaluated by a manner similar to phase-plane analysis. Evaluation of the indicial response of nonlinear time-variant control systems in the presence of gaussian random disturbance is discussed. The advantage of the procedure is applicability to the calculation of response of nonlinear time- variant control systems with various types of pre-assigned inputs, even in the presence of random disturbance. (auth)