Parameters' Optimization Design Of Nonlinear Hydropneumatic Suspension

The hydro-pneumatic suspension with ideal stiffness and damping character is suitable for mineral trucks. However, design methods before haven't exerted the advantages of hydro-pneumatic suspensions. Therefore, study on nonlinear stiffness and damping parameters optimization in a new way is of great significance on improving the riding comfort, elevating drivers' fatigue and prolonging the life of vehicles.Now the optical design of the nonlinear stiffness and damping of the hydro-pneumatic suspension is usually based on theories of the linear system and the revises have to be conducted subsequently through experiments of suspensions as well as full vehicles, which call for long terms and high costs. However, utilizing the equivalent linearization method combined with the multi-body dynamic simulation can increase the accuracy of results and shorten research periods.This paper designs the hydro-pneumatic suspension system's stiffness and damping of one kind of mineral truck to optimize its ride comfort. The contents are as follows:Firstly, design studies of the front hydro-pneumatic suspension's equivalent linear stiffness and damping are conducted based on a two-freedom system. The relationship between variations of stiffness and damping and ride comfort is analyzed. The best equivalent linear stiffness and damping coefficients are found with the ADAMS/Insight so that the best nonlinear stiffness and damping curves of the hydro-pneumatic suspension system are built.Secondly, designs of experiments of both front and rear hydro-pneumatic suspensions' equivalent linear stiffness and damping coefficients are conducted based on a half vehicle vibration model. The relationship between the combination styles of the two suspensions' equivalent stiffness and damping and ride comfort is analyzed. The best variation range of ratios of offset frequencies and damping ratios between two suspensions is obtained and the best equivalent linear stiffness and damping coefficients are found with the ADAMS/Insight. Then the optical nonlinear stiffness and damping curves of front and rear hydro-pneumatic suspension systems are built respectively.Finally, to optimize the ride comfort of the mineral truck both loaded and unloaded simultaneously, a comprehensive assess function that reflects the ride comforts of two statuses is constructed. Change stiffness curves in the model constantly until the most suitable nonlinear stiffness characteristic is found to achieve the best comprehensive ride comfort. The comparison of simulation results proves the effectiveness of the optimization.