Analysis And Optimization Of A Heavy-duty Truck’s Cab Vibration

With the social and economic development as well as the gradual introduction ofthe country’s economic control policies in the recent years, the demand of theheavy-duty trucks in the domestic market was sharply rising and the heavy-duty truckbecame the important transport of the long distance transportation and the large-scaleproject in the national economy. This paper started with the phenomenon of aheavy-duty truck’s cab vibrated abnormally, did a road test of the truck to measure thevibration signal, and then analyzed the vibration of all the parts of the truck and findthe fault existed in the various system of the truck. Finally, used the software tosimulate and analyze and find the way to solve the fault of the truck, and promoted theride comfort of the truck.The paper did a vibration signal road test, and got the signal of every importantposition of the truck. The paper used the vertical direction acceleration RMS value ofthe truck seat to evaluate the ride comfort objectively, and the results showed that thecab vibration was abnormal and the ride comfort was poor needed to be improved. Bycarrying out the coherence function, the spectrum analysis and the self-powerspectrum analysis of the test data, the paper got the conclusion that the vibrationsource came from the road, the damping effect of the front suspension vibrationisolation system was ideal, and the damping effect of the cab suspension system wasbad needed to be improved.Because of the cab vibration was so abnormal and the ride comfort was poor andthe damping effect of the cab suspension wan not ideal, the paper first did the modalanalysis of the cab and got the first three modal frequencies, the results showed themodal frequencies (18.98Hz) were all higher than the cab vibration excitation (about3Hz), and the influence of the modal frequency to the cab abnormal vibration waslittle. The paper improved the ride comfort mainly from the parameters optimizationof the cab suspension system. The paper set up the simple model of the cab suspensionsystem by used the software ADAMS, and used the orthogonal experiment designmethod to optimize the cab suspension system parameters. The paper used thedamping force mathematical formula fitting to optimize the nonlinear dampingparameter. After optimization, the vertical direction acceleration RMS value of thetruck seat reduced by16.28%when the speed was50km/h. From the results of the verification test, the vertical direction acceleration RMS value of the truck seat undervery test speed reduced ideally, the cab vibration optimized and the ride comfortimproved ideally as well.