Abstract
A wheeled mobile robot traversing on sandy terrain should be aware of its mobility hazard such as wheel slip that will be a trigger of immobilizing wheel stuck in loose sand. A wheel having large diameter/width generally possesses high traversability on sandy terrain because its large contact area can moderate steep stress concentration between wheel-terrain interactions, resulting less deformation of sand. However, such large wheel is relatively heavy and needs large envelope to be stowed, and also it requires large input power for its rotation. Therefore, a well-defined guideline for wheel design, namely how to determine an appropriate wheel size, is of an important issue. This paper presents a method providing the most appropriate wheel parameters (wheel radius and wheel width) which maximizes wheel traction performance on sandy terrain. The proposed method consists of the following four steps. First, a wheel parameter set is assumed as uncertain parameter, and defined by a statistical distribution form (i.e. Gaussian, Uniform). Then, a wheel-terrain contact model is employed to define an evaluation metric for the wheel traction performance. Subsequently, a stochastic method for uncertainty analysis called SRSM (stochastic response surface method) is to obtain an equivalent system model which is expressed as a polynomial function composed of the wheel parameters. Finally, the most appropriate set of wheel parameters which maximizes the evaluation metric is then numerically obtained by solving an optimization problem of the equivalent system model. In this paper, each step of the proposed method is introduced and then a simulative study of the wheel parameter evaluation is described.
