Partial Contact Force Controllability in Active Wheeled Vehicles

Abstract

This paper presents a geometric approach for solving the force distribution problem in active wheeled vehicles (AWVs) moving on uneven surfaces. Here an active vehicle is defined as a system that includes independent actuators for all its internal joints. In general, AWVs do not possess omni-directional mobility, and they possess fewer actuators than the number of wheel-ground contact force components. This article presents an approach for separating the contact force vectors into active and passive components such that there exists an invertible square matrix that maps the active contact forces to the actuator efforts. An appropriate force allocation algorithm can then be developed for these systems. The concepts introduced in this article are demonstrated via an example of AWVs on uneven terrain. An example of force distribution in active legged vehicles (ALVs) that possess the same number of actuators as contact forces is also provided for comparison.