A Coefficient of Friction Estimation Monitoring System for Autonomous Off-Road Vehicles

A Coefficient of Friction Estimation Monitoring System for Autonomous Off-Road Vehicles Using Wide Area Augme- ntation Systems (WAAS) and a Magnetic Pulse Generator Shaft Encoder Abstract: The proposed work introduces a means of developing a friction measurement system that has many applications in vehicle safety systems such as Anti-lock Braking System (ABS) and Traction Control System (TCS). Rapid weather and road conditions would change the behavior of the vehicle and a need of a system to eliminate the associated hazard is crucial. This system depends mainly on merging the output of two subsystems; a Wide Area Augmentation System (WAAS)and counting magnetic pulses generated by gear teeth on the vehicle’s axle (Wheel Shaft Encoder). This will lead to a better accuracy of the measurement of the Coefficient of Friction. Moreover, the physical relation between the different parameters of the system such as the slip angel, friction, normal force, and stiffness will improve the feedback of implementing a fully autonomous vehicle. 1 Introduction: 1.1 Background Vehicle traction control, which is composed of an anti-lock braking system (ABS) and a traction control system (TCS) during acceleration, can enhance vehicle performance. The objective of such control is to maximize tire traction by preventing the wheels from locking during braking and from spinning during acceleration, while maintaining adequate vehicle stability and steer ability. Simply, wheel slip occurs when the forces applied to a tire exceeds the traction available to that tire. This force is applied in two ways: Longitudinally {draw:frame} {draw:frame} : From engine or brakes Laterally {draw:frame} {draw:frame} : From driving around a curve, i.e. change of direction Therefore, if the sum of these forces is bigger than the traction, then it is very obvious that wheel slip will occur [1]. The most important point for creating a wheel model for a vehicle is the exact observation

References: [2] U. Kiencke, L. Nielsen: “ Automotive Control Systems: For Engine, Driveline, and Vehicle”, Springer Science + Business Media, New York, 2005.