Programs for CAD of Multivariable Control Systems in both the Time and Frequency Domains

Abstract

In this paper a description of a suite of programs used in the computer-aided design of linear, timeinvariant, multivariable control systems is given. Algorithms which have been programmed for control systems design in the time-domain include optimal state feedback, Kalman filtering, pole-placement, observer design, and output feedback design with dynamics if necessary. The option to design controllers for continuous- or discrete-time systems is generally provided in the above programs. Controller design in the frequency-domain is carried out using a package which incorporates the direct-Nyquist array, inverse-Nyquist array, and characteristic locus design methods. User interaction with this package is via a vector-refresh graphics workstation.The foregoing controller design algorithms in turn rely upon a number of support programs. These may include eigenvalue and eigenvector routines, function minimisation routines and LU Factorisation routines, for example. Programs for the conversion between time- and frequency-domain system representations are also available. Associated programs for the manipulation of polynomials include a root-finding routine, and for matrix polynomials a greatest common left- or right-divisor routine, and the Smith-normal form routine. A routine for finding the McMillan form of rational matrices is also available. Other support facilities include a matrix utility which allows the storage and retrieval of system data in a common database- as well as the execution of standard matrix operations -- and a plot facility for the time-simulation of open- or closed-loop systems. The entire suite of design, simulation and support programs described above is supported by a user-friendly, help facility. Examples of interactive design sessions, including the design of a power system stabiliser, are given in the paper, with results being taken directly from computer hardcopy.