Abstract
In this paper, we present two design schemes of continuous-time model reference adaptive control system (MRACS) which are robust to modeling error of a plant. At first, we present a design scheme of MRACS in which we utilize a design approach of variable structure systems (VSS). In this design scheme, we can ensure robustness property of MRACS in the presence of modelling error by choosing appropriate parameters which are decided by the designer and make the output-error between the plant and the reference model asymptotically zero. However, it is possible that the use of VSS design approach causes chattering phenomena in this design scheme. To overcome this drawback, we also propose another design scheme in which we consider the prevention of chattering phenomena.