Research On Control Strategy Of Hydraulic Adaptive Bearing Of Railway Emergency Repair Bridge

Railway bridges,as key structures for railways to cross oceans or other obstacles,are crucial in achieving smooth handover of railway lines.When the original railway bridge is damaged,the railway emergency repair bridge can serve as a temporary bridge for trains to pass smoothly,providing convenience for logistics support and emergency repair work.Traditional elevated floating bridges often use passive control bearing or semi-active control bearing systems in emergency repairs,which greatly limits the stability of trains passing on the floating bridge.Especially when the floating bridge system is in a wave interference environment and there is partial load on the train,the bridge not only generates severe vibration,but also displacement synchronization errors on both sides,seriously affecting the safe passage of the train.In order to solve the above problems,based on the research at home and abroad,this thesis takes the 87 type emergency repair steel beam as the research object,analyzes the vibration response of the bridge,studies the active control strategy,uses the hydraulic adaptive bearing based on fuzzy sliding mode control to suppress the vibration of the bridge,and analyzes the joint simulation results.Firstly,analyze the characteristics of the electro-hydraulic servo valve and derive the dynamic characteristic equation of the electro-hydraulic position servo system.Analyze the state feedback and output feedback of the system,and establish a state space model of the electro-hydraulic position system based on position variables and deviation variables.The environment of the hydraulic adaptive bearing is divided into three working conditions: fixed bridge pier,static water floating pier,and wave interference floating pier,and the bearing model and closed-loop control structure diagram are established respectively.Secondly,use Adams to build a train bridge water dynamics system model,analyze the vibration response of the rigid flexible coupling system,and use the coupling method to analyze the contact force between the wheel and rail.Establish dynamic equations of bridge structures using finite element method and solve dynamic problems using numerical methods.By using potential flow theory,analyze the first-order wave forces and analyze the coordinate system of the floating structure.Based on the three working conditions of the hydraulic adaptive bearing,establish an overall model of the floating bridge system and calculate the equivalent elastic stiffness of the water buoyancy.Then,a cross coupling synchronization control strategy is proposed to address the synchronization error caused by train bias and wave loads.Fuzzy sliding mode control and three state feedback control are used to reduce the buffeting of the system,suppress the transverse and vertical vibration of the beam structure,and compensate the displacement of the bridge end caused by the flexible foundation and wave lifting.Finally,a fuzzy sliding mode control module and a hydraulic system module are built using Matlab/Simulink,and combined with Adams model,the joint simulation results of the bridge under three conditions of free vibration,sweep excitation and vehicle load are analyzed.The simulation results show that the hydraulic adaptive bearing can provide real-time compensation for water level changes,significantly control bridge vibration,reduce displacement synchronization error,and have strong robustness against external interference.