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

Abstract

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.

Cable Vibration Control using Magnetorheological Dampers

“…In addition, an adapter was provided for each cable to supply adjustable current to the MR dampers to achieve the maximum damping according to different vibration conditions. After the full installation of MR dampers, a series of field vibration measurements and tests lasting 45 days (Duan, 2004;Duan et al, 2004) had been conducted in the bridge site with the following purposes: (i) to investigate the overall performance of the MR damping system under different types of excitation conditions; (ii) to identify the exciting mechanism of rain-windinduced cable vibrations, and (iii) to experimentally verify the real-time feedback semi-active control strategies developed. It was found that some cables were susceptible to the rain-wind-induced vibration when the dampers were working in the passive mode without current input, and the vibration was then effectively suppressed when the optimal or sub-optimal current/ voltage input was applied.…”

“…However, clipping treatment at many time steps may significantly affect control effectiveness and its realization is practically not easy when the used MR dampers are not fast enough in responding to the applied magnetic field. Keeping in mind the above points, a state-derivative feedback control strategy based on acceleration measurement has been proposed within the framework of reciprocal state space (Duan et al, 2004). Based on appropriate energy weighting, the commanded control force is directly implementable by MR dampers in most situations and can be switched to passive-off damping force of the MR dampers in the small velocity range.…”

Stay cable vibration mitigation: A review

“…Duan et al (2004, 2005c) proposed collocated state-derivative feedback control based on the finite difference model, along with validation using the cable-MR damper system on the Dongting Lake Bridge. Wu et al (2007b) and Wu et al (2006a) proposed voltage adjusting method based on directions of measured displacement and velocity.…”

Experimental evaluation of a self-powered smart damping system in reducing vibrations of a full-scale stay cable

“…By using a medium-scale cable, Christenson [7] experimentally analyzed the performance of an MR damper in mitigating cable vibrations, with the results demonstrating an excellent performance. Duan et al [8][9][10] carried out a series of field comparative tests of cable vibration control using MR dampers. It was shown that the equivalent modal damping ratios of the cable-damper system were noticeably dependent on the vibration amplitude.…”