Three-Dimensional Kinematic Analysis of the Actuated Spoke Wheel Robot

Abstract

A current problem for mobile robots in unstructured environments is their lack of general mobility. Wheeled, treaded, and legged robots each have their advantages and disadvantages, but they all lack the flexibility to be able to cope with a wide range of terrain. The actuated spoke wheel system was presented in an earlier work as an alternative locomotive method that allows unique mobility capabilities to cope with various situations. This paper presents the three-dimensional kinematic analysis of the actuated spoke wheel system with no slip and no bounce constraints at the ground contacts for a robot using a two actuated spoke wheel configuration. The first analysis will cover the case when the axle is coplanar with the line connecting the contact points, called the pivot line, and show results from two examples, corresponding to steady state turning and, in the special case, straight-line walking. The second case will describe the configuration when the pivot line is skew with the axle, comparing the robot in this configuration to an SPPS spatial mechanism. This comparison will lead to the recommendation of a more general model, based on the SPPS mechanism, that will be used to analyze the motion in both configurations.