Active tendon control of suspension bridges

Abstract

The paper first reviews the theory of active tendon control with decentralized Integral Force Feedback (IFF) and collocated displacement actuator and force sensor; a formal proof of the formula giving the maximum achievable damping is provided for the first time. Next, the potential of the control strategy for the control of suspension bridges with active stay cables is evaluated on a numerical model of an existing footbridge; several configurations are investigated where the active cables connect the pylon to the deck or the deck to the catenary. The analysis confirms that it is possible to provide a set of targeted modes with a considerable amount of damping, reaching ξ = 15%. Finally, the control strategy is demonstrated experimentally on a laboratory mock-up equipped with four control stay cables equipped with piezoelectric actuators. The experimental results confirm the excellent performance and robustness of the control system and the very good agreement with the predictions.

ℋ∞ optimization of an integral force feedback controller

“…In addition, one should also notice that the system becomes dynamically softer with the application of IFF control, meaning that the actuator does not contribute to the static stiffness of the system when the control gain is set to the values other than zero. Marneffe (2007) and Preumont et al (2016) reported to use a high pass filter to compensate the static stiffness, which however would result in the invalidity of the derived optimal feedback gain and the compromise of the unconditional stability. Further investigations will be a subject of future work.…”

“…During the past few decades, the potential of using active damping systems (Preumont, 2011) has thus been extensively explored, where additional actuators and sensors are employed and the resultant control force is formed to be proportional to the structure velocity in order to increase the structural damping. A wide range of control techniques such as integral force feedback (IFF) (Preumont et al, 1992(Preumont et al, , 2016, direct velocity feedback (Balas, 1979;Alujevic´et al, 2014), and positive position feedback (Fanson and Caughey, 1990) have been proposed to implement such active damping systems. One common feature of these active damping controllers is that they are relatively easy to implement, where not much prior knowledge of the system is required.…”

“…One important design concern with such a control system is how the control gain of the feedback loop should be set to optimally damp the vibration of the host structure. The most widely used optimization criterion for designing an IFF controller was proposed in Preumont et al (2016), which is referred to as the maximum damping criterion. With this technique, the optimal feedback gain is sought to obtain the most achievable damping for one specified structural mode.…”

A Multi-Degree of Freedom Tuned Mass Damper Design for Vibration Mitigation of a Suspension Bridge

“…Therefore, the dissipation of the vibration energy generated by the dynamic loadings is a central issue in their design. At present, the use of damping systems such as tuned mass damper (TMD) [7], viscous dampers [8,9], or active tendon control [10] is a classical way to alleviate the vibrations in structures. This study aims at the design of multi-degree of freedom TMD for vibration damping of a suspension bridge deck.…”

Damping system for long‐span suspension bridges

“…The dampers are connected to the main cables by smaller cables, and in order to keep these in tension, a pretensioning is applied via a loaded spring in parallel with the damper. A somewhat similar configuration was considered in Preumont et al using piezoelectric active tendon control in a model for damping of vibrations from pedestrian loads on a footbridge. The present damping system is targeting the lowest vertical and torsional modes to suppress flutter‐type instability of the aeroelastic system.…”