Variable structure model reference adaptive control using only input and output measurements

A variable structure model reference adaptive controller (VS-MRAC) using only the input and output measurements of the plant is proposed. Stability and transient properties are analysed and discussed. Remarkable transient behaviour is revealed, in particular, model following can be perfectly achieved in a finite time. The effect of plant input disturbance is investigated and the performance of the VS controller is also shown to be qualitatively superior to that obtained with (conventional) integral adaptation algorithms. A link between the VS-MRAC and the conventional MRAC is suggested. Simulations are presented to highlight the theoretical results.