Design of a Simple Controller to Control Suspension Bridge Non-linear Vibrations due to Moving Loads

Abstract

The flexibility and low damping of the long span suspended cables in suspension bridges make them prone to non-linear vibrations due to wind and moving loads. In this paper we consider the dynamic response of a suspension bridge due to a vertical load moving with a constant speed on the bridge deck. Control mechanisms are suggested to generate control forces to control the non-linear vibrations in the bridge deck and the suspended cables. A simple design is presented for the controller based on the feedback of the velocity measurements taken at the control force location. The design is made first on a linear model before applying it to the actual non-linear system. The method is applied on three different types of control mechanisms. Comparison between the controlled responses using the three controllers indicates that, in addition to the method of designing the control actions, the feasibility of the active control depends mainly on the type of the control mechanism.