Quantitative I/O-controllability assessment for uncertain plants

This paper deals with the calculation of the optimal control performance for linear time invariant plant models in the context of the screening of possible control structures. Compared to other approaches, e.g. the use of the relative gain array or other controllability indices, the proposed computation of the attainable control performance gives a quantitative assessment of a control structure without reference to a particular controller structure other than the assumption of linear control. In the time domain, control performance is measured in a least squares sense while constraints on manipulated and controlled variables can be included. The extension of the method presented here integrates the frequency domain condition for robust stability. Uncertainties are represented by the well known MDelta structure which renders the method generically applicable