Variable structure model reference adaptive control based on two-degree-of-freedom compensators scheme

In this paper, a variable structure model reference adaptive control system (MRACS) based an two-degree-of-freedom compensators scheme (2 DOF) is proposed. First, a MRACS with fixed compensator is constructed using the 2 DOF proposed in Masuda et al. (1994). Second, the fixed compensator is replaced by a switching compensator. The switching algorithm is determined in order that the estimated parameter can converge more rapidly. Since the Proposed method is based on the 2 DOF structure, the switching compensator works only when the parameter uncertainties are large. The boundedness of all signals in the closed-loop system and the convergence of the output error are proved. Finally, simulation results are illustrated to show the effectiveness of the proposed method.