Proposed design of a single-wheel test rig for a Lunar rover

This thesis aims to study, analyze, and design a test rig for Lunar rover wheels to understand their lifecycle under various operational configurations. The proposed test rig features a single-wheel with a configurable vertical load, which is suitable for characterizing the first-order of magnitude in wheel-soil interaction and traction capabilities. However, it misses out on vehicle-induced forces deriving from suspensions and the interaction between each wheel. More in advance, the proposed system is designed to meet a set of specific requirements: it must be dismountable, capable of rotating around its own axis with controlled velocity, able to support a maximum load of 150 kg (equivalent to half of the rover’s total weight), and allow for the measurement of the inclination of the arm to which the wheel is attached. An additional feature includes the ability to vary the wheel’s camber angle in 5° increments. The thesis begins with an introduction to space exploration and past rover missions, emphasizing the critical role of wheels and the engineering tests conducted to address potential operational challenges. This is followed by a chapter dedicated to terramechanics, outlining the fundamental models and parameters used to analyze wheel-soil interaction in extraterrestrial environments. A comprehensive review of existing test rigs and rover wheel designs provided the foundation for the development of the proposed system. The final design features a single-wheel configuration built primarily with aluminum profiles, ensuring modularity and ease of assembly. The wheel is mounted on a two-meter-long arm capable of overcoming terrain obstacles and rotating around a central axis, while also allowing for the application of configurable vertical loads. The design phase, conducted mainly in a 3D CAD environment, is supported by structural calculations and engineering evaluations for the sizing and selection of components, including sensors, wiring, and the motor. Numerical simulations were also performed, yielding promising results that validate the prototype’s feasibility. In conclusion, the thesis presents the key features of the system, highlighting the innovative solutions adopted, the promising results obtained, and provides a timeline estimate through a Gantt chart. Finally, an analysis of the lessons-learnt offers a comprehensive overview of the project, identifying and suggesting potential design variations and improvements. The work conducted in this thesis lays solid technical foundations and provides essential insights for the potential physical realization of the single-wheel test rig designed for Lunar rover wheels.