MULTIVARIABLE ROBUST CONTROL SYSTEM: APPLICATION TO A PLASMA REACTOR

This paper describes a multivariable H-2-H-infinity robust control approaches, for an ill conditioned, difficult to control system, given by a plasma chemical reactor CF4/O-2. The control of such a system resulted, in the past, in a slow, oscillatory coupled response. The goals of applying robust controls, is the achievement of a decent smooth response with minimum oscillations and overshoot. In the pursuit of this goal, we proceed to the quantification of uncertainties affecting the plasma process. Then, the robustness conditions in closed loop, to be achieved, are clearly stated. Only then, the H-2 and H-infinity algorithms are applied, after the construction of the augmented system resulting from the standard process form. To provide the advantages of the H-infinity algorithm, we applied the H-2 one and compare the results obtained between the two controls.