Study On Some Key Technology Of Vehicle Suspension System

The research objects of this thesis are passive shock absorber, semi-active shock absorber and semi-active suspension of vehicle suspension system. Physics parameter based model of passive shock absorber, innovational mechanism with safety redundancy function, and new semi-active control strategy are studied.A new physics parameters based nonlinear complex model of passive shock absorber was presented. In the model, mechanical dynamics sub-model and fluid dynamics sub-model were modeled with analytic method, while the deformation dynamics sub-model of valve plate was modeled with numerical method based on plate large deformation theory. This complex physics parameter based nonlinear model takes account of the effect of gas pressure, effective bulk modulus of gas mixed oil, bulk modulus of cylinder shell, leak, friction, etc. Validation with test data shows that the model can simulate the damping character and hysteresis of shock absorber well.An innovational mechanism with safety redundancy function of magneto-rheological fluid shock absorber was presented. This fail safe magneto-rheological fluid shock absorber gives attention to controllability of semi-active shock absorbers and safety of passive shock absorbers. Dynamics model, electromagnetic model and permanent-magnetic model were given. Based on the models, prototype shock absorbers were designed and manufactured. Test data show that the models are effective and precision.A new semi-active control strategy based on the new designed shock absorber was studied. The negative stiffness control strategy with legible physics signification was introduced to control the semi-active suspension. The negative stiffness control strategy was compared with sky hook control strategy, and the compare results were validated on the quarter car vertical dynamics test system.A quarter car vertical dynamics test system was established. Two key technology of the test system were discussed, they are robust controller of electro-hydraulic position servo system and methods of reproduction of road roughness in time field.