SUMMARYA high-"delity PC-based control system has been developed to improve the tracking characteristics of a small-scale seismic motion simulator used for testing structural control designs. This work outlines the development and testing of the control system. First, the simulator hardware is described in detail. The process of constructing a mechanistic model of the system and identifying model parameters is then described. Next, a closed-loop feedback/feed-forward control algorithm, based on an optimal receding horizon formulation, is developed. The control design was tested and the results indicate that the seismic shake table precisely tracked reference seismic motions.
We investigate semi-active control for a wide class of systems with scalar nonlinear semi-active actuator dynamics and consider the problem of designing control laws that guarantee stability and provide sufficient performance. Requiring the semi-active actuator to satisfy two general conditions, we present a method for designing quickest descent controllers generated from quadratic Lyapunov functions that guarantee asymptotic stability within the operating range of the semiactive device for the zero disturbance case. For the external excitation case, Ž bounded-input, bounded-output stability is achieved and a stable attractor ball of . ultimate boundedness of the system is computed based on the upper bound of the disturbances. We show that our wide class of systems covers, in particular, two nonlinear actuator models from the literature. Tuning the performance of the simple Lyapunov controllers is straightforward using either modal or state penalties. Simulation results are presented which indicate that the Lyapunov control laws can be selected to provide similar decay rates as a ''time-optimal'' controller for a semi-actively controlled single degree of freedom structure with no external excitation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.