A robust adaptive controller without apriori knowledge from modelling errors

This paper presents a design approach of robust adaptive controllers using the techniques of backstepping and parameter projection. With this design scheme, no apriori knowledge on the unmodelled dynamics is required for controller implementation. It is shown that, global stability of the system is guaranteed in the presence of unmodelled dynamics and bounded external disturbances. A bound for the output tracking error is obtained as a function of the sizes of the unmodelled dynamics and external disturbances. In the ideal case where there is no modelling error, perfect tracking is ensured.