Smart structures: Part II  Hybrid control systems and control strategies

In a companion paper, the writers reviewed significant work done on active and semi-active vibration control of structures performed in the past decade or so. In this paper, journal articles on the hybrid vibration control of structures and control strategies, published during the same period, are reviewed. They include hybrid mass dampers, semi-active base isolators, actuators with passive dampers, and semi-active Tuned Liquid Column Dampers (TLCD) with passive dampers. A key element in successful implementation of smart structure technology is an effective control algorithm to compute the magnitudes of internal forces to be applied to the structure. Various improved or new control strategies developed for civil structures are reviewed in this paper. They include modified LQR and LQG, neural network-based, fuzzy logic, sliding mode and wavelet-based controllers. Studies on optimum placement of control devices are also summarized.