COMPUTATIONAL-COMPLEXITY REDUCTION IN SCALED H-INFINITY SYNTHESIS

The H-infinity control problem with constant scaling is considered. Th is problem is known to reduce to a search for matrices satisfying line ar matrix inequalities (LMIs) and an additional nonconvex constraint. Recently, globally convergent algorithms to solve this nonconvex feasi bility problem have been proposed. A major factor that determines the computational complexity is the number of nonconvex constraints. This paper gives verifiable conditions on the plant under which the reducti on of nonconvex constraints is possible. The conditions appear to be a strong requirement, but in fact, they are nautrally satisfied in cert ain problems. (C) 1997 Elsevier Science Ltd.