Reduced-order H∞ and LQR control for wind-excited tall buildings

摘要

Because of the large number of degrees-of-freedom involved in modeling wind-excited tall buildings, three reduced-order control methods are presented and their performances are investigated systematically. These include the state reduced--order control, criti- cal-mode control and simple modal control. The important issues associated with reduced-order control, control spillover and obser- vation spillover have been addressed. Both the robust H∞ and lin- ear quadratic regulator (LOR) control algorithms have been used. Applications of static output feedback controllers, that utilize only a limited number of sensors without an observer, are also investi- gated for practical implementations of control devices on wind- excited structures. The spatially correlated wind loads, as defined by a cross--power spectral density matrix, have been used to com- pute the stochastic response of the full-order tall building to dem- onstrate the performance of each control method. Numerical results indicate that as long as enough modes are considered in the reduced--order system, the performance for both state reduced- order control and critical-mode control are comparable to that of the full-order control. However, the performance of the simple modal control for reducing the acceleration response of wind- excited buildings is not satisfactory because of the spillover effects. Simulation results further indicate that static output controllers for reduced-order systems provide a possibility for reducing the required number of sensors. From the practical implementation standpoint, the state reduced-order control may be preferable to the critical--mode control, since it does not require an observer.