Decentralized active tendon control and stability of cable-stayed bridges

In this paper, active tendon control of cable-stayed bridges subjected to vertical seismic excitation is investigated by using the decentralized control technique. A control system, made up of control cables and the corresponding control mechanism, is employed for seismic response control of cable-stayed bridges. A simply supported cable-stayed beam model with lumped-mass idealization is used as the bridge model for control design. A control algorithm in terms of the decentralized control approach specific for large-scale system is then developed with the bridge model being decomposed into two interconnected subsystems. A set of decentralized controllers that minimize the performance index of each subsystem and guarantee the stability of overall structure are designed by use of the scale Lyapunov functions. The proposed active control algorithm in application to cable-stayed bridges has the advantage that each subsystem can be controlled independently, using only the local information. The performance of the proposed control algorithm is verified through numerical simulation