Axle Drive and Brake-Based Traction Control Interaction 2011-01-2160
Brake-based traction control systems (TC), which utilize the brake of a spinning wheel of the drive axle, are widely used in passenger cars and light trucks, and recently were applied to all-wheel drive construction equipment. Such machines employ various types of interwheel drive systems (i.e., axle drives such as open differentials, limited slip differentials, etc.) to control torque split between the drive wheels and, thus, improve vehicle traction performance.
As experimental research showed, the interaction between the traction control system and the axle drive can lead to unpredictable changes in vehicle performance. Lack of analytical work in this area motivated this study of the interaction and impact of the two systems on each other and the dynamics and performance of a drive axle. The paper presents an analysis of the torque/force distribution between the driving wheels of an axle with open differential and limited slip differential with different torque bias characteristics when the traction control system is on and the driving wheels have the same/different gripping conditions. Also, the normal tire loads vary due to lateral inclination of the axle. Results of analytical research explain the nature of extra torque loads of the wheels, determine the yaw moment, and show energy losses in tires and the axle brake mechanisms. These results layout the requirements needed for the braking torque and control algorithm development of the traction control system to work “cooperatively” with limited slip differentials.