Tire-road friction estimation for a wheel-driven field robot

To improve the stability and controllability of vehicles, especially for wheel-driven field robot system, the friction between tire and road are investigated. For the commercial vehicle, various techniques including vehicle dynamic control, traction control, and anti-lock braking system have been developed and adopted. To accomplish these systems, the most important factor is to estimate the tire-road friction characteristics. Most of the tire-road friction estimation algorithms are based on the tire slip ratio and the tracking force obtained by a tire model. However, because the slip ratio and tracking force are difficult to be measured directly and defined strictly, additional estimation algorithms to get these values are required. Therefore, in this paper, in the view of traditional friction definition, we propose a tire-road friction estimation method that uses the traditional friction model. Also, to get normal force for the vehicle system, dynamic force distribution algorithm is suggested. The real car experimental result shows good performance of the proposed methodology.