A Wheel and Vehicle Mobility Index Based on Traction and Velocity for Optimization of Mobility Performance

Abstract

In this paper, two new indices for wheel and vehicle mobility performance suitable for mobility performance optimization are proposed based on the wheel circumferential forces and the vehicle actual linear velocity. The indices are intended for on-the go assessment of mobility for autonomous real-time optimization of wheel power distribution. The wheel mobility performance (WMP) characterizes the mobility performance of a wheel in terms of its traction and velocity with regard to a potential but unachievable maximum. The index is extended to a vehicle with a given number of drive wheels, where the traction characteristics and theoretical velocities may be different at each wheel, as the vehicle mobility performance (VMP). The VMP index is demonstrated through a simulated comparison of multiple driveline configurations of a 4x4 vehicle on different terrains to the optimal value. The optimal mobility is computed through an objective function with the use of Lagrange Multipliers which determine the optimal distribution of vehicle forces and slippages which achieve optimal mobility.