| With the rapid development of the rail transit industry,the highest running speed of high-speed EMU is increasing.The higher running speed makes the operating environment of the connecting parts of the vehicle end even worse,which has a more acid test and higher requirements for the safety and stability of the train operation.Especially when the train passes through the curve,turnout and knick point,the relative motion between each part of the vehicle and two adjacent vehicles will be more severe.Therefore,it is necessary to study the relative position of two adjacent vehicles and the movement condition of the vehicle end connecting parts to provide reasonable vehicle ends clearance and the reasonable arrangement of the connecting parts of the vehicle ends for vehicle design,and avoid the interference of the connecting parts of the adjacent vehicle ends in the operation of the train.The research methods of inter-vehicle relationship include road test,simulation and bench test.The road test is of high cost and high risk.The simulation can not only make up for the shortcomings of the road test,but also has the advantages of short test period,and being suitable for different vehicles and lines.However,the simulation requires a great quantity of input parameters,and has a lot of approximation and simplification process.Therefore,the simulation has a certain gap with the actual situation.Compared with road test and simulation,the bench test is less affected by external environment,and can accurately reproduce the road condition and carry out the limit test which is difficult to realize in the road test.The motion parameters of each part of the vehicle end can be measured through bench test,which can provide the test basis for the design of the vehicle end.Therefore,CRRC Changchun Railway Vehicles Co.,Ltd commissioned Jilin University to develop an inter-vehicle relationship test bench.The test bench can provide the simulation of 6-DOF motion posture for two adjacent vehicles.Based on the project of the inter-vehicle relationship test bench,the contents of this paper include the following aspects:(1)Build the model of train-track system dynamicsThe track model is described by the Frenet frame.Given the radius of curvature and the curve superelevation of each point on the track center line and the vertical coordinate corre-sponding to the vertical curve,all information about the track can be calculated.A train model consisting of 3 vehicles is established.Two adjacent vehicles are connected by a vehicle end connection device,and each vehicle contains a car body,2 bogies and 4 wheelsets with a total of 42 degrees of freedom.The dynamic model of vehicle end connection device including the coupler,damper and windshield are established.The vehicle and track are coupled by wheel rail contact force,and the wheel rail contact model including the wheel rail contact geometry,the wheel rail normal force and the wheel rail creep force are established.(2)Research on the design scheme of the inter-vehicle relationship test benchThe design scheme of the inter-vehicle test bench is composed of two 6-DOF platforms,14 actuators and two vehicle end simulators.The motions of two 6-DOF platforms are controlled by coordinating the motion of the 14 actuators to simulate the actual vehicle end running state.The measurement system is responsible for the collection of relevant datas in the process of the inter-vehicle relationship test.The control system is mainly responsible for inputting control instructions to the test bench to make the test bench move according to the requirements.The monitoring system is used to monitor the state of the test to ensure the safety and reliability of the test.(3)Research on the algorithm of solving the test spectrum of the inter-vehicle relationship test benchSolving the control command of the actuators of the test bench is the premise and key technology to realize the simulation of vehicle end motion attitude on the test bench.The track,train and test bench are studied as a system.The postures of the train running on the line are transformed into the expansion amount of the actuators by the algorithms of space coordinates position and pose transformation and inverse kinematics.Based on the two different models of the kinematic model of train-test bench system and the dynamic model of train-test bench system,the paper presents the algorithms of the two test spectrums.The control commands of the 14 actuators are solved by simulation,and the control instructions obtained by the two methods are compared and analyzed.(4)Solution of relative position and posture of vehicle ends based on simulationIn order to ensure the safety and reliability of the bench test,the virtual prototype model of the inter-vehicle relationship test bench was built before the bench test.The control commands of 14 actuators are one-to-one inputted into the model as a test spectrum.Whether the test spectrum can be applied to the bench test can be determined by simulation.At the same time,the relative position and posture of the adjacent vehicle ends are obtained to compare and analyze with the relative position and posture of the vehicle ends obtained from the bench test to verify the accuracy of the bench test results.(5)Solution of relative position and posture of vehicle ends based on bench testAfter the simulation confirms that the test is safe and feasible,the bench test is carried out and the relative motion of the adjacent vehicle ends running on the line are simulated.The test results are compared with the simulation results to verify the accuracy of the test.Through the calculated results of relative position and posture of vehicle ends,the swing angles of the coupler,the windshield angles,lateral staggered distance of the two vehicle ends,and the minimum distance between two adjacent vehicle ends can be calculated to evaluate the running state of the vehicle ends when the train is running.According to different line conditions,the corresponding bench test was carried out,and the different test results were compared and analyzed. |
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