Abstract
This paper presents a robust scheme for the direct type of model reference adaptive control system (MRACS) and its stability analysis in the presence of unmodeled dynamics and measurement noise. This scheme is characterized by the use of adaptive law with dead zone and integral type of fixed compensator. The adaptive law prevents the adjustable parameters from drifting and the fixed compensator improves the deteriorated control performance caused by the use of dead zone. The stability of the system is analyzed by a new method which evaluates an exponentially weighted norm, called as L2δ norm, of the regressor signals and then applies the Gronwall lemma. This method enables us to analyze the stability based on the L2-property of the parameter adjusting rate, which is guaranteed by the adaptve law. Effectiveness of the scheme is demonstrated by the simulation carried out for a simple plant with 1st order nominal part.
