Numerical singularity analysis of a tire model for real-time traversability simulation

A military unmanned ground vehicle (MUGV) is operated without human onboard for short-range surveillance and reconnaissance on the battlefield. This MUGV has to control driving speed by estimating road roughness on the driving path. To predict the limit stable speed, driving speed estimation using a vehicle dynamic analysis was proposed. A single prediction process of the proposed method needs a full driving simulation along the given path. So, a highly efficient dynamic model and simulation technique are required for a real-time analysis. Since a tire force is dominant factor that affects vehicle behavior, a precise tire model is one of the most important elements in vehicle dynamic simulation. The real-time traversability simulation demands highly efficient and stable numerical model, but the longitudinal slip sometimes causes a numerical singularity problem from its definition. This problem makes it hard to integrate ODEs when using not only explicit integration method but also implicit integration method. This paper shows the reason for this problem on numerical point of view, and an improvement idea is proposed.