Research On Mechanical-Electric Transmission Tracked Vehicle Steering Performance Prediction

The steering performance is an important evaluation index of tracked vehicle dynamic performance.In this paper,one type of vehicle with electro-mechanical transmission(EMT)is studied specifically.The steering performance is analyzed and predicted both under the ideal conditions and the actual conditions considering the slipping of track-contact-ground.In this paper concerning EMT,several typical system's steering characteristics under the ideal conditions is analyzed.And the speed,torque and power balance relation of power coupling mechanism scheme for double side motors coupling drive transmission,dual motor drive transmission and Series-parallel Hybrid transmission are calculated.The power demand,rapidity,controllability and stability of steering process of the three transmission systems is analyzed.The characteristics of different transmission systems are summed up according to the analysis above.The parameters of turning resistance moment,turning radius,turning angular speed and acting force between tracks and ground are calculated based on the kinematical and dynamic model considering the influence of steering centrifugal force.Based on the Matlab/Simulink platform,the simulation model of the 40t-level vehicle is established.Tracked vehicle testing results show that steering model established in this paper agrees with the actual turning process well.Based on the model above,the steering considering slip steering performance is analyzed.In this paper,the steering performance of tracked vehicle is analyzed according to the slip ratio of the two sides of the track,the relative offset of the turning center,the correction coefficient of the turning radius and the correction coefficient of the turning angular speed.The analysis results show that comparing with the calculation results,the turning radius is between 1.2 to 1.5 times,and the turning angular speed is 62% in slipping steer situation.At the same vehicle speed,the stability and controllability of turning process deteriorate with the decreases of turning radius.At the same turning radius,the controllability and stability of turning process deteriorate with the increase of vehicle speed.The power demands and working state of engine and motors during steering process are obtained based on the Simulink model to provide the theoretical support on the steering process control.