Modified bang-bang control law for structural control implementation

Linear quadratic regulator (LQR) formulation has been used extensively in many control systems designed for structural control applications due to its stability and robustness. However, recent results obtained from simulation, laboratory experiments, and full-scale structural applications show that it is difficult to use linear feedback-control laws to produce a significant peak-response reduction when the peak response occurs during the first few cycles of the time history. On the other hand, although another class of well-known optimal control laws, so called "bang-bang" control, has been investigated for several decades, their potential in civil engineering structural control has not yet been exploited. The purpose of this paper is to present a new implementable control law for response control of civil engineering structures, based on the optimal bang-bang control principle. Through a series of simulation studies and experimental verification in the laboratory using a model structure, it is shown that the proposed new control law can significantly improve peak-response reduction under the same constraints imposed on the control resources as in the LQR case.