Modeling of the Wheel-Soil Contact for Planetary Exploration Rovers

Abstract

In order to lead the cost-intensive mission of a planetary exploration rover to a success, tremendous efforts must previously be undertaken in development and design. An important issue in the exploration rover development is the consideration of the wheel-soil contact, which is necessary to ensure the maneuverability of a rover, especially on loose and soft soil. As a consequence, the modeling of the contact reactions between wheel and soil has become a subject of research, because it can help to reduce costs in the development by using simulations instead of designing expensive prototypes. In this master thesis the focus is on semi-empirical models of terramechanics, however the operational capability of these models is strongly limited due to their high degree of simplification. For this reason, extensions to existing models are investigated in order to verify if these extensions improve the operational capability of semi-empirical models. In particular, the suitability of different approaches of the so-called bristle model, which is a concept of friction modeling, are implemented in an existing simulation environment and then tested in simulation, as well as on a test bed. In order to validate these model extensions, as well as to investigate the wheel-soil contact behavior in soft soil, a field campaign on the linear guided Single-Wheel Testbed at the DLR Oberpfaffenhofen are performed.