Stability of limit cycles in relay control systems

The stability of limit cycles in relay feedback systems is investigated in this paper. Balasubramanian's stability matrix has been modified to make it applicable for time delay systems as well for systems having a relative order of 1. Astrom's state space method has been extended for the prediction of limit cycles and for the derivation of the stability matrix for relay feedback systems having relays with hysteresis and dead zone. Extensive simulation results are given to substantiate the methods presented. Copyright (C) 1998 IFAC.