Flutter control of long-span suspension bridges

The dynamic stabilization of a sectional model of a long-span suspension bridge is considered. Feedback control is achieved using leading- and trailing-edge flaps as actuators. While a wide variety of control systems is possible, we focus on compensation schemes that can be implemented using passive mechanical components such as springs, dampers, and a rack and pinion mechanism. A single-loop control system is investigated that controls the flaps by sensing the main deck heave velocity. A symmetrical control scheme is used on both flaps to make the feedback system insensitive to the wind direction. The key finding is that the critical wind speed for the flutter instability of the sectional model of the bridge can be greatly increased, with good robustness characteristics, through passive feedback control.