GPS Based Real-Time Identification of Tire-Road Friction Coefficient

Project summary:

This project focused on the development of real-time tire-road friction coefficient estimation systems for snowplows that can reliably estimate different road surface friction levels and quickly detect abrupt changes in friction coefficient. Two types of systems were developed in this study: a wheel-based system employing a redundant wheel (used primarily for benchmarking purposes) and a novel vehicle-based system employing vehicle motion measurements from differential GPS and other onboard vehicle sensors to calculate friction coefficients. The vehicle-based measurement system has several advantages over current commercially available wheel-based systems, including: reliability (skidding wheel not required for operation); low total cost (required components have several other useful applications on a high-tech maintenance vehicle); and quicker and more accurate measurements under a wide range of operating conditions. In addition to winter maintenance applications, real-time identification of the friction coefficient is also expected to be valuable to other vehicle systems, including ABS, skid-control, collision avoidance and adaptive cruise control systems.