| The air suspension is widely used of buses, because it can change its stiffness characteristic by charging and discharging gas to get ideal stiffness curve, riding comfort, driving stability. However, there has not been optimization match semi-active air suspension under different driving conditions, for it is restricted by identification of driving road condition, air suspension stiffness theory, control law, and so on. With the development of auto-industry and the increase of driving speed, higher requirements of driving safety and riding comfort are put forward. In this paper, some research was conducted, aiming at the problems. The research works are as follows:(1) With ride vibration analysis based on 1/4 model of vehicle, by the relation of body vibration acceleration, travel speed and vehicle parameters, the identification model of driving road condition was built, based on vibration and travel speed.(2) According to thermodynamic theory, by grogin theorem, the air spring stiffness analytic formula under different heights was build.(3) According to the ride vibration analysis and requirements of driving comfort and handing stability, the optimum damping control model of air spring vehicle was built.(4) According to engineering thermodynamics theory with its structural characteristics, a high degree control law mathematical model was build, and a control method was put forward of adjusting the air spring height to change the stiffness.By simulation, its optimal ratio mathematical and control theory are correct and the result show that semi-active suspension system developed meets the requirements of driving and the riding comfort and it can reduce the vehicle roll angle, This research has important theoretical and application valve for the design and control of semi-active air suspension. |
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