Research on Transmission Gear Modification of EMUs Based on Random Forests Algorithm
There exists a gear meshing impact during the gear transmission of EMU,which exacerbates the vibration of the gearbox and impacts its service safety.As a result,the rigid-flexible dynamic model of a motor vehicle with gear transmission system is established in SIMPACK,and the SIMPACK-ISIGHT simulation platform is constructed to calculate the optimal modification parameters of transmission gears,and its optimization effect on gearbox vibration is investigated.The experimental design is based on the root mean square values of vibration acceleration of gearbox at speeds of 200 km/h,250 km/h,300 km/h and 350 km/h.The test results show that altering the gear modification parameters significantly affects the vertical vibration acceleration of the gearbox,but not the lateral vibration acceleration.The surrogate model is established using the random forests algorithm,and the NSGA-Ⅱ algorithm is used to call the surrogate model to optimize gear modification parameters.The reduction in the root mean square value of the vertical vibration acceleration of the gearbox is taken as the optimization rate,and the weighted average of the optimization rate at each speed is taken as the goal.The optimization results indicate that gear modification can optimize the root mean square value of vertical vibration acceleration of the gearbox at each speed,and that the optimization effect of gear modification on vertical vibration of the gearbox gradually becomes worse with increasing speed.Finally,using the gear modification parameters obtained by average distribution weights as an example,the changes of vertical vibration acceleration of the gearbox before and after gear modification are compared.The computation results indicate that in the time domain,the magnitude of vertical vibration acceleration of the gearbox decreases at each speed subsequent to gear modification.In the frequency domain,the magnitude of the vertical vibration acceleration of the gearbox at each speed at the gear meshing frequency significantly decreases,with an average decrease of 65.01%.
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维普
