Research On Driving Characteristics Of Multi-axle Mechanic And Electric Compound Wheel Drive Vehicle

In this paper, by taking a multi-axles mechanic and electric driving vehicle for the study, the following contents are studied, including the establishment of the vehicle longitudinal dynamics model, the formulation of traditional two-parameter dynamic shift strategy, the development of three-parameter dynamic shift strategy based on torque distribution, and the study of fuzzy shifting control based on curve recognition, which are of great importance for improving the acceleration performance as well as the capability to driving on complex road conditions of a multi-axles mechanic and electric driving vehicle. The research work can be summarized as the following points:The structure and working principle of the driveline is analyzed. According to the characteristics of the transmission system, which hydraulic mechanical transmission is used in two front axles while distributed electric driving system is used, the vehicle longitudinal dynamics model is established based on characteristics of various transmission components. Meanwhile, simulation model based on Matlab/Simulink is established.Theoretical analysis of the links and differences between the two kinds of gearshift judgment is taken in developing the dynamic shift strategy. The traditional two-parameter dynamic shift strategy is formulated base on the joint working characteristics of the engine and the torque converter. And an experiment was conducted to verify the correctness and rationality of the gearshift strategy.For the two-parameter gearshift strategy can not be fully applicable to the multi-axles mechanic and electric driving vehicle, a kind of method to formulate the three-parameter gearshift strategy based on throttle, vehicle velocity, and torque distribution has been proposed. In this method, torque distribution coefficient ti is introduced to quantify the power take off(PTO) from the engine. At last, simulation and analysis of vehicle dynamic performance with the optimized gearshift strategy was taken to verify the correctness and rationality of the optimized three-parameter gearshift strategy.The vehicle yaw rate and side-slip angle are used as control variables to establish the yaw moment decision modules based on PID control. A nonlinear superposition method which introduced the distribution coefficient is used to establish DYC control system. A optimization allocation method which take tire adhesion utilization rate as the optimal control target is established to distribute auxiliary yawing moment into each wheel's longitudinal force. A offline simulation platform is set up under the environment of Matlab/Simulink software. Through the simulation research, the control effect of the stability control system designed in this paper is verified.