STABILITY AND EXPONENTIAL STABILITY OF AN ADAPTIVE-CONTROL SCHEME FORPLANTS OF ANY RELATIVE DEGREE

Relying on a new adaptive pole assignment control scheme for plants wi th unknown relative degree and uncertain order which can be made minim um phase by means of a relative degree-one first order parallel compen sator, a new adaptation mechanism is proposed in this note in order to tackle with the problem of tile attainment of an exponentially stable behavior of the output error. In particular, the connection between e xponential stability and persistent excitation is outlined, and a comp lete stability analysis is performed.