Modified sliding-mode bang-bang control for seismically excited linear structures

Recently, sliding-mode control (SMC) methods have been investigated for app lication to seismically excited civil engineering structures and have prove d to be effective control strategic methods. On the other hand, although an other class of well-known optimal control laws, the so-called 'bang-bang' c ontrol, has been investigated for several decades, their potential in civil engineering structural control has not been fully exploited. The purpose o f this paper is to present a new control law for civil engineering structur es, which is the sliding-mode bang-bang control (SMBBC). The SMBBC method i s a combination of the SMC and the bang-bang control. In consideration of a ctuators not suitable for high-speed switching of control forces in the SMB BC in practice, modified sliding-mode bang-bang control (MSMBBC) law is pro posed and demonstrated to be able to provide the same control effects as th e SMBBC case. Condition modified sliding-mode bang-bang control (CMSMBBC) l aw is also investigated in this paper. In the CMSMBBC case, actuators act o nly when response quantities exceed some designated threshold values. The d etermination method of maximum control-forces for actuators is investigated through example computation. The performance and robustness of the propose d control methods are all demonstrated by numerical simulation. Simulation results demonstrate that the presented methods are viable and an attractive control strategy for application to seismically excited linear structures. Copyright (C) 2000 John Wiley & Sons, Ltd.