A new model reference robust control for the systems with disturbances

A new design technique of the model reference robust control is proposed for single input single output (SISO) minimum-phase (with respect to the relation between the input and the output) dynamical systems with unmatched disturbances. By using the transfer function method, based on the variable structure system theory, the special signals generated by the disturbances are approximately estimated for two possible cases of the systems. Then the estimated signals are applied to the corresponding model reference controllers to cancel the influence generated by the disturbances for each case. The output tracking error can be made arbitrarily small without the requirement that the control energy is available as much as it is needed. Design example and simulation results are presented to show the practicality and effectiveness of the proposed algorithm.