| Special tractor-semitrailer, which consisting of one tractor and one semi-trailer, carry a large antenna and other equipments. It is very important to ensure the stability and safety in the running. Running stability is the capability that the semi-trailer follows the tractor without transverse sway and capsize in the running and braking process. Tractor-semitrailer running stability is one of the important measures on evaluating handling stability.First of all, the dissertation analyzed the calculating process of the semi-trailer body roll angle when the vehicle turning by the tractor-semitrailer simplified mathematical model. Through establishing the braking mathematical model, the dissertation analyzed the ideal braking force distribution and actual braking force distribution, and obtained a reasonable lock braking sequence between three tractor-semitrailer axles.Second, the parameters of full vehicle dynamics model were obtained based on blueprint lookup, calculation and CAD modeling. The full vehicle rigid-flexible coupling dynamics simulation model including rubber bushings and flexible bodies was established by using the mechanical system simulation software ADAMS, the model of air suspension including height control valve and lateral stabilizer bar were emphases. The tractorsemitrailer dynamics model laid the foundation of running stability simulation analysis.Last, Virtual tests were simulated under the operating condition based on national vehicle test standards, including steering wheel angle step input trial, steering wheel angle impulse trial and rapid double lane change trial, steady circle trial, straight line braking trial and turning braking trial, the running stability simulation results of semi-trailer was analyzed. In the end, the optimization design was conducted based on the running stability of tractor-semitrailer.Virtual tests manifested that running stability of the special tractor-semitrailer satisfy the design requirement. |
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