Research Of Automotive Dynamics And Kinematics Based On Rigid-Flexible Coupling Suspension

Due to the development tendency of suspension parts design toward slight weight, the flexible deformations of the suspension parts can't be neglected. In vehicle dynamics, the suspension parts are regarded as rigid body generally, which can't meet the demand for research, therefore, it is very necessary to research the flexible elements vibration and the influence on the system dynamic performance.Based on theory of multi-body system dynamics, the mechanical system simulation software MSC.ADAMS is applied to build the rigid-flexible coupling full vehicle model that based on the flexibility of suspension parts. The suspension kinematics and ride performance of full vehicle are researched and compared with the simulation results of rigid multi-body model. Especially, new methods in establishing vehicle dynamic model, analytical method, and evaluation method are proposed in this dissertation.In the research of front rigid-flexible coupling suspension kinematics, the results show that the flexibility of the suspension parts have apparent effects on the changes of wheel alignment parameters in the motion of the suspension. Especially, the effect of toe angle is the most apparent. Contraposed shortages of the road surface model in ADAMS, the road surface model for random inputs with left and right wheels correlated is established based on the filtered white noise method. This model is very applicable to various vehicles for simulation and extends the elements of ADAMS road surface model library. More attention is paid to the influence of the flexibility of suspension parts for ride performance. The time-frequency responses of vehicle chassis accelerations, suspension working space and dynamic tire load etc. are analyzed and compared with rigid multi-body model, by which are made some conclusions. The weighted seat acceleration in time domain isobtained through the digital filter of frequency weighted function, and the r.m.s value of weighted acceleration is calculated based on it. Finally the ride performance of vehicle is evaluated, which improves the traditional frequency domain evaluation method.