INDIRECT ADAPTIVE NONLINEAR CONTROL OF DISCRETE-TIME-SYSTEMS CONTAINING A DEAD-ZONE

In this paper an indirect adaptive output feedback control result whic h applies to discrete time systems containing a dead-zone nonlinearity and linear dynamics is presented. A plant parametrization that is lin ear in a set of unknown parameters is first developed. This is accompl ished by forcing the regional descriptions of the dead-zone to be enti rely contained in the definition of a regressor. This is convenient fo r estimation, since adaptation for the parameters of the separate regi ons of the non-linearities is implicitly accommodated by the regressor . Unfortunately, this parametrization necessitates multiple estimates of the zeros of the plant. To overcome the difficulty of designing a f eedback/feedforward controller given multiple estimates of the zeros, we implement a non linear 'zero-resolving' prefilter. This prefilter t o the plant allows one to design a feedback/feedforward controller bas ed on one set of zeros.