A robust discrete-time direct adaptive control algorithm (Q1319501)

After a short presentation of some approaches in robustness of the discrete-time adaptive control algorithm in Section 2 is reviewed the ordinary discrete-time adaptive control algorithm with dead-zone. In Section 3 are presented main results about a new robust direct adaptive control algorithm. It is considered the case where the upper bound of the disturbances is unknown and it is used an estimate of \(\eta\) in the dead- zone function. By considering a Lyapunov function candidate the stability and convergence of the new adaptive control system are analysed. A theorem which assumes the global stability of the new algorithm is given. This new robust discrete-time directe adaptive control algorithm uses the dead-zone but no upper bound on the disturbances is required apriori. Results on global stability and convergence are also established.