Nonlintools: GUI Tool for Analysis and Design of Nonlinear Control System

Abstract

A class of nonlinear control system, in which the nonlinearity can not be expressed by any analytical expression, is difficult to analysis and design. Describing Function (DF) and Phase Plane Trajectory (PPT) are well established frequency and time domain methods for analysis of such systems. These methods are graphical methods and very time consuming methods. Novel GUI tool based on above two methods is presented. MATLAB based ’nonlintools’ is user friendly tool for analysis of nonlinear control systems. It is possible to find out existence, stability, frequency and amplitude of limit cycle very quickly. Functions and features are added such a way that it can be also used for design of nonlinear control systems to achieve desired performance. It is very simple to learn this tool. One can easily use it with preliminary knowledge of DF and PPT methods.