Computer-Aided Control Engineering Environment for the Synthesis of Nonlinear Control Systems

We describe a second-generation toolset for computer-aided nonlinear control system analysis and design based on sinusoidal-input describing function (SIDF) methods. There are two main elements in our CAD software: a simulation-based program for generating amplitude-dependent SIDF input/output models for nonlinear plants, and a frequency-domain nonlinear compensator design package. Both of these are described in detail. This software can treat very general nonlinear systems, with no restrictions as to system order, number of nonlinearities, configuration, or nonlinearity type. An overview of the application of this software to the ATB1000 Army test facility (comprising an electromechanical pointing system with flexible modes) will be provided, to illustrate the use and efficacy of these tools.