DESIGN OF CONSTANT GAIN DISSIPATIVE CONTROLLERS FOR EIGENSYSTEM ASSIGNMENT IN PASSIVE SYSTEMS

Partial eigensystem assignment with output feedback can lead to an uns table closed loop system. now ever, output feedback with passive linea r time-invariant systems, such as flexible space structures, is guaran teed to be stable if the controller is dissipative. A novel approach i s presented for synthesis of dissipative output feedback gain matrices For assigning a selected number of closed-loop poles. Dissipativity o f a gain matrix is known to be equivalent to positive semidefiniteness of the symmetric part of the matrix, A sequential procedure is presen ted to assign one self-conjugate pair of closed-loop eigenvalues at ea ch step using dissipative output feedback gain matrices, while ensurin g that the eigenvalues assigned in the previous steps are not disturbe d, The problem of assigning one closed-loop pair is reduced to a const rained solution of a system of quadratic equations, and necessary and sufficient conditions for the existence of a solution are presented. A minimax approach is presented for determining parameters that satisfy these conditions, This method can assign as many closed-loop system p oles as the number of control inputs, A numerical example of damping e nhancement for a flexible structure is presented to demonstrate the ap proach.