91-0020 Hybrid Control of Seismic-Excited Nonlinear and Inelastic Structural Systems J.N.Yang, Z.Li, A.Danielians 1991 University of California at Irvine 136 PB92-143171 15 Refined versions of the instantaneous optimal control algorithms for nonlinear or inelastic systems are proposed. Their advantage is that the control vector is determined directly from the measured response state vector without tracking a time dependent system matrix. Applications of these algorithms to various types of aseismic hybrid control systems are demonstrated. These hybrid systems include combinations of sliding isolators or lead-core rubber bearings and active devices such as actuators, active mass dampers, etc. The performance of various control systems are evaluated and compared, and the advantages of hybrid systems are demonstrated. This report also offers an instantaneous optimal control formulation for nonlinear and inelastic systems which incorporates the specific hysteretic model of the system. The resulting optimal control vector, which satisfies both necessary and sufficient conditions of optimality, is obtained as a function of the total deformation, velocity and the hysteretic component of the structural response. As above, applications of this optimal algorithm to various hybrid systems are demonstrated. Structural Control, Inelastic Systems, Instantaneous Optimal Control Algorithms, Velocity Feedback, Hybrid Control Systems, Hysteretic Systems, Nonlinear Systems, and Acceleration Feedback.