There are many practical control problems where the control action is deter
mined by switching among a given set of control laws. This paper presents n
ecessary and sufficient conditions to test for quadratic stabilizability an
d for robust stabilizability with a quadratic storage function for switched
controller systems. Algorithms which can be used to construct appropriatel
y stabilizing control laws are also presented. (C) 1999 Elsevier Science Lt
d. All rights reserved.