Multi-objective Nonlinear Control of Semiactive and Regenerative Systems

Many modern structural control devices for earthquake engineering applications are essentially passive devices with adaptive parameters. Semiactive and regenerative forcing systems are two examples. In order to achieve performance superior to time-invariant passive systems, these devices must be controlled in the nonlinear regime, and consequently it is nontrivial to develop feedback controllers which adhere to analytically-computable measures of closed-loop performance. In the context of stationary random vibration, current state-of-the-art control design methods do not guarantee to simultaneously keep the variances of a set of important structural response quantities below desired thresholds. In this paper, a generalized control design approach is presented which guarantees bounds on the variances of multiple response quantities. The method is illustrated through simulation of a six-story, base isolated structure, with two control devices. Both semiactive and regenerative designs are considered in this example.