1992 Volume 5 Issue 7 Pages 274-282
This paper proposes a design method of MRACS (Model Reference Adaptive Control System) for unknown plants in the presence of deterministic disturbance or periodic disturbance, so that the output error will converge to zero as time tends to infinity.
In the traditional adaptive control systems dealing with disturbance, the disturbance was usually restricted to be deterministic. To remove the effect of disterbance, the general way was to use extended system including a disturbance model, or to use integral compensators. Here, a new disturbance compensating method is proposed, in which disturbance compensating signals are introduced into MRACS, and are combined adaptively to cancel the effect of disturbance. In this proposed method, because the filter signals of input and output are composed in the same way as the disturbance free cases, the MRACS has a simple constructure. Even for the periodic disturbance with unknown shape, if the period is known, by using Fourier series, the proposed method is also possible to remove the effect of this sort of disturbance. Furthermore, being used, disturbance compensating signals in MRACS, it is possible to take the initial responses of filters into account, and the characteristics of parameter convergence can be improved. The effectiveness of this proposed method is illustrated by some computer simulations.