Study On Stiffness Damping Characteristics And Comfort Optimization Of Nonlinear Seat Suspension For Special Engineering Vehicles

Special engineering vehicles generally apply high stiffness suspension to meet the requirements of large bearing capacity.Besides,the driving road surface is poor and the operating environment is bad,which further aggravate the vehicle vibration.For high stiffness suspension,there is a little room for comfort optimization,so the damping effect of seat suspension for special engineering vehicles has a significant impact on the driver’s whole body vibration and driving comfort experience.Nonlinear seat suspension can solve the problem of low-frequency vibration isolation of traditional linear seat suspension.Therefore,the in-depth study of nonlinear seat suspension is a vital and practical topic to improve the comfort for special engineering vehicles.At present,the vibration isolation effect of wishbone nonlinear seat suspension used in most special engineering vehicles is not obvious and the comfort experience is not high.In order to solve the above problems,the following research is carried out in this paper.(1)The theoretical model and simulation model of the nonlinear seat suspension are established,and the static test of seat suspension is carried out.The stiffness and damping characteristics of wishbone seat suspension are obtained by theoretical analysis and experimental verification,which showed that the wishbone seat suspension has weak nonlinear stiffness within the load range and the comfort of the seat can not be effectively guaranteed.(2)In order to further explore the dynamic characteristics of the non-linear seat suspension,a domestic loader is selected for the real vehicle test.After denoising and detrending the measured data,the spectrum is obtained by Fourier transform.Then the magnitude and the causes of vibration were analyzed.The results indicated that the seat suspension performs well at idle speed and can effectively block the high-frequency influence from the engine.However,the effect of medium and low frequency vibration isolation is obvious,and the comfort evaluation is poor in the flat road driving,uneven road driving and working conditions which is the most concerned about of the loader.(3)A new segmented wishbone seat suspension is designed in this paper to improve the nonlinear stiffness characteristics of the seat.Firstly,the nonlinear elastic force is expressed by 9-degree homogeneous polynomial,and the ideal stiffness characteristic curves are obtained by optimization.Secondly,the dynamic model of segmented seat is established and solved,and the stiffness parameters of segmented wishbone seat are obtained by optimizing the model.Finally,the optimized effect is verified.The results show that the root mean square value of the seat support plate’s acceleration after optimization are reduced by 64% and 80%under driving conditions and working conditions.(4)The prototype of segmented seat suspension is processed,and the real vehicle test is carried out on the seat.The acceleration time history curves,frequency domain curves and seat comfort evaluation are obtained,which manifested that the segmented wishbone seat suspension has more outstanding low-frequency vibration isolation performance and more stable vibration isolation effect than the wishbone seat suspension under various working conditions.