Research On Active Vibration Damping Of Large Truss Bridge Inspection Vehicle

Large truss bridge inspection vehicle can be used to detect and repair large-width bridges.During the work,the workers need to be sent to the bottom of the bridge,thus forming a long steel structure platform suspended in the space.Due to the elasticity of the material,the vehicle body and working platform of the bridge inspection vehicle will vibrate under the disturbance such as workers’ walking,bridge vibration and wind load,etc.These vibrations will reduce the stability and comfort of the working platform.In order to improve the vehicle’s adaptability to external environment disturbances,and to create a more stable working platform for the workers,this paper takes a certain model of truss bridge inspection vehicle as research object and do research on its vibration control.Establish mechanical equation of bridge inspection vehicle under disturbances.PID control algorithm is designed for the active suspension to reduce the vibration of the vehicle body.LQG control algorithm is designed for the active mass damper to reduce the vibration of the working platform.The results comparison between the simulations in which control force is applied and those in which have no control force shows a good damping effect.Firstly,simplify the bridge to an equal-beam model,establish its mechanical equation of transverse vibration,according to Euler-Bernoulli beam hypothesis.Obtain the generalized force exerted by moving vehicle on bridge,use Mat Lab to make the response curve of vibration at bridge mid-span.Secondly,design PID control algorithm for active suspension.Establish differential equations of the vehicle suspension,obtain system transfer function by Laplace transform.Use Simulink to simulate vehicle body vibration response under disturbance.Design the gain coefficients of proportional,integral and differential links of PID controller,use Simulink to simulate the system with PID controller to see control effect of active suspension.Thirdly,simplify the mechanical model of working platform into distributed mass model,and establish its mechanical equation.Simplify pedestrian load model,use Mat Lab to calculate the vibration responses of pedestrians walking in each section of the platform.Calculate the wind load applied to the platform,use Mat Lab to calculate the vibration response of the platform under wind load.Finally,establish the mechanical equation of working platform involved with control force.Obtain feedback gain matrix K by using LQR control algorithm.Design Kalman filter and calculate Kalman filter gain.According to LQG control algorithm,vibration control models of working platform under pedestrian excitation and wind load excitation are established in Simulink respectively.Make a comparison between under-control vibration response and no control vibration response of the platform.