Steering Returnability Analysis And Optimization Of Double-Front-Axle Vehicles

Among vehicle handling stabilities, the returnability performance is very important. It has close relationship with safety performance. So, the research of returnability performance is of great meaning and value.This paper takes the double-front-axle tractor for the study, according to the market feedback, there exists problems at returnability aspect:in low speed conditions, while the steering wheels finish returning, residual yaw rate is too heavy; in high-speed conditions, the vehicle responds slowly, the steering wheels can’t return to straight-ahead position in time. To these kind problems, we carry on cornering steer release test^constant radius cornering test and steering portability test. It can not only help defining the research questions, but also provides basis for establishing mathematical model.In the analysis of domestic and international automobile steering returnability, propose two research methods:one is based on the balance of working and energy, establish the equation of active steering aligning torque work and resistance torque work, by writing calculation procedures in Matlab software, analyze the impact of various parameters on the steering returnability; the other one is based on the vehicle dynamic response during returning process, establish the kinematics differential equation of steering wheel angle that yaw rate and steering wheel angle can be predicted and the simulation model in the Matlab/Simulink module, relevant parameters are written m file, analyze the steering wheel movement around the kingpin and the response of kinds parameters.And then, on the basis of multi-body system dynamics theory, depending on the geometric and the technical parameters of the tractor, established vehicle model in MSC.ADAMS/Car module. By using virtual prototype model, conducted cornering steer release simulation、constant radius cornering simulation and steering portability simulation. Finaly, verified the model is accurate by compared with empirical data.At last, combined with the analysis of the theory, significant parameters are selected for returnability performance optimization which providing direction towards Further improvement.