Theoretical and experimental studies on semi-active feedback control of cable vibration using MR dampers

This paper presents theoretical and in-situ experimental studies on semi-active vibration control of bridge cables using magneto-rheological (MR) dampers. The feedback control is accomplished using only one MR damper and one accelerometer collocated near the lower end of the cable. A new control strategy, state-derivative feedback control, is formulated within the framework of reciprocal state space (RSS). This state-derivative feedback control strategy is novel in the sense that it directly uses acceleration information for feedback and state estimation, which is usually the only measurand available in practical cable vibration control implementation. More importantly, the control force commanded by this strategy with an appropriate energy weighting tends to be dissipative and therefore implementable by semi-active MR dampers without clipping. Numerical simulations of state-derivative feedback control for a 115m long stay cable in the cable-stayed Dongting Lake Bridge are conducted under different excitation conditions, and then experimental validation of the prototype cable is carried out in the bridge site with the help of the real-time control system dSPACE. Good agreement is observed between the simulation and experimental results.