Research On Vehicle Comfort Based On Random Vibration

With the overall development our country,cars have become indispensable transportation means for families and people also have higher and higher requirements on the comfort of cars.Therefore,it is necessary to study the comfort of the vehicle,and try to improve the smoothness of the vehicle and the comfort of the passengers.The unevenness of the road is the main incentive for the vibration of the vehicle,which is obviously random.There are a lot of repetitive analyses in the optimization of the vehicle parameters,and the conventional stochastic vibration analysis method is not so efficient,which greatly limit the vehicle's application in practical use.This paper is based on the theory of random vibration,and adopts the efficient virtual excitation method to the analysis of vehicle comfort.Firstly,the random vibration response of the vehicle-bridge coupling is solved.Then,the importance of the various factors that affect the comfort of the vehicle is analyzed by the orthogonal test method.Finally,based on the sensitivity analysis,the structural parameters of the vehicle are optimized.In this way the smoothness of the vehicle and the comfort of the passengers are improved.The main research contents are as follows:(1)Based on the efficient pseudo excitation method,the vibration response of the vehicle-bridge coupling system under random excitation is solved.The 1/2 automobile model and the simply supported beam bridge model are established,and the virtual form of road roughness excitation is constructed according to the pseudo excitation method.The vehicle-bridge coupling system under non-stationary random excitation is analyzed by MATLAB program,and the vertical vibration response of the vehicle and the bridge is obtained.The influence of vehicle speed and bridge roughness grade on deflection and vehicle vertical vibration is also studied.(2)Based on the orthogonal test,the influence degree of various working conditions and vehicle parameters on vehicle comfort is analyzed.By establishing a vehicle model of eight degrees of freedom,and considering the coherence effect of the random excitation at the left and right rut,this paper will use the vertical weighted acceleration RMS value of the seat as the evaluation index of the comfort.All these help to analyze the comfort of the vehicle.The orthogonal test is designed to analyze the influence of various conditions and vehicle parameters on the comfort.At the same time,it figures out which affect is more obvious,and to make preparation for the analysis of next step.(3)Based on the sensitivity analysis,the vehicle parameters are optimized to improve vehicle comfort.The first and second order sensitivity of comfort evaluation index is obtained based on virtual excitation method.Combined with the sequence linear programming,the vehicle parameters are optimized to obtain the local optimal solution of the vehicle parameters under the constraint condition and the vehicle comfort is improved.The vehicle design provides some reference.By this way,we can improve the vehicle comfort,and offer reference to vehicle design.