| The Mining dump truck ride comfort is one of the important performances, it not only on passengers comfort or goods integrity, but also on the dynamical and economical performance of vehicle, working life of auto parts. As mining dump trucks often work in complex and poor conditions, drivers feel tired easily;in addition, the suspension system may be subjected to large deformation and exhibits strong nonlinear characteristics as well as time-varied characters because of its load-bearing large. So, the ride comfort has been a major performance that makes it succeed more easily in the competitive market of same kind of vehicles. And the above situations may be improved by using a new type of nonlinear hydro-pneumatic suspension, which can satisfy the requirements of vehicles, and improve controllability/stability and ride comfort. Further more, the hydro-pneumatic suspension will suppress the vehicle vibration induced by the road excitation if designed properly and can relieve the riding fatigue of the driver as well as prolong the life of the vehicle. As well, hydro-pneumatic suspension is of compact structure, large carrying capacity, good damping performance, etc.Selecting the Mining electric wheel dump truck (SF33900) as the research object, this paper built the dynamic model of the hydro-pneumatic suspension system. Referring to the entire truck riding comfort experiment and taking ride comfort as optimization objective, the ideal nonlinear curve of the variable suspension stiffness and damping was figured out through the optimization of the suspension system under different vehicle speeds. Main contents of this paper are as follows:1. The experiment of entire truck riding comfort was made, and a further study was conducted on the root mean square value of acceleration, attenuation coefficient, power spectrum density of each testing positions. The shock absorption effect of hydro-pneumatic suspension and other components were evaluated and analyzed by using of these evaluation indicators.2. An identification algorithm of physical parameters of the nonlinear stiffness and damping characteristics of Hydro-pneumatic suspension system was developed, making use of Daubechies wavelet’s compactness and regularization and least-square method. The representative models which could fully describe the nonlinear mechanic characters of the Hydro-pneumatic suspension were defined as analogical3-ordered multinomial using least square method based on the identification results. These models were ultimately used in the dynamic simulation of the entire truck. At last, the identification results were verified by using multi-body dynamics simulation software Adams/view.3. The model of engineering dump truck with seven degrees of freedom was set up, which included cubic nonlinear stiffness and cubic nonlinear damping characteristics, then the simulation model was established by Simulink and the ride comfort of the model was simulated and analyzed; At last, the simulation model was validated by test.4. The optimization design variables were determined by single factor analysis, and the mathematic model of the Hydro-pneumatic suspension system for optimization under different working conditions was established by using weight coefficient method, the ideal stiffness and damping parameters and curves were obtained after the combined optimization design between Simulink and GA algorithm, and this study laid a foundation for the optimization of the gas height and pressure and the structural parameters of Hydro-pneumatic suspension. The simulation results showed that:the root mean square value of the body acceleration was greatly brought down on different conditions, maximum achieved38.69%, minimum also had13.12%, so the vehicle ride comfort could be significantly improved. |
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