Multivariable tuning regulators: The feedforward and robust control of a general servomechanism problem

A new notion of computer identification, as opposed to the conventional plant identification problem, is introduced in this paper. It is assumed that it is desired to aynthesize a robust feedforward-feedback controller for an unknown plant so that asymptotic tracking, in the presence of disturbances, occurs. The only assumptions made regarding the description of the plant model are that: (i) the plant is linear and plant-invariant, (ii) the uncontrolled plant is stable. Note that it is assumed that the order of the plant modal is unknown. Necessary and sufficient conditions which allow the robust feed-forward-feedback compensator to be synthesized so that the controlled system is stable and so that asymptotic tracking, in the presence of both measurable and unmeasurable disturbances, occurs are obtained. An algorithm which allows the controllers to be synthesized is given. Some numerical examples are included to illustrate the results.