Analysis of Piecewise Linear Systems by the Method of Integral Equations

Abstract

Analysis of piecewise linear systems may require the solution of high-order linear differential equations whose parameters are constants within a given region but change into different constants for adjacent regions. The multiple regions of such a system may be identified with discrete intervals and it is a simple matter to obtain the system response by the method of integral equations. These solutions are given in the form of convergent infinite series, the terms of which may be easily evaluated by a digital computer. The time interval of each region is found by substituting successive values of these truncated series until the required boundary conditions are satisfied. The method is applied to a third order-type two system whose sustained oscillation, when subjected to dry friction, is to be eliminated by dead-zone compensation. The system has four regions with different parameters for each region of the differential equations which are converted into Volterra integral equations of the second kind. The variables are iterated within the digital computer until a convergent solution is found for the condition of sustained oscillation. Procedures are given to determine critical values of dead zone for various ramp rates at which the system is stable.