Design and Evaluation of Skating Motions for a Dexterous Quadruped

Abstract

This paper describes skating locomotion for a quadruped robot with dexterous limbs. The emphasis is on design of omnidirectional motion primitives and quantification of resulting speed and accuracy when traversing different types of smooth but potentially non-flat terrain. In particular, we study trade-offs between using four-wheeled versus three-wheeled skating maneuvers. In four-wheeled skating, motions have the benefit of symmetry, so that errors due to wheel slip should theoretically cancel out on average. Three-wheeled skating, by contrast, introduces significantly more asymmetry in configuration and contact force distribution over time; however, it has the advantage of guaranteeing continuous ground contact for all skates when terrain has bumps or other curvature. We present simulation results quantifying errors for each approach, for various terrains. Our results allow us to tune motions to reduce biases and variability in motion, which are primarily due to accelerations as locomotion begins.