The rocker-bogie mobility system is a six-wheeled mobility system with the ability to equilibrate ground pressure amongst its wheels and traverse obstacles up to one wheel diameter in height; it has been used previously on NASA's Sojourner, Spirit, Opportunity and Curiosity rovers. This paper presents the mechanical design of an instrumented rocker-bogie mobility system for Kapvik, a 30 kg planetary micro-rover prototype developed for the Canadian Space Agency. The design of the wheel drive system is presented, including: motor selection, gear train selection, and performance limits. The design of a differential mechanism, which minimizes the pitch angle of the rover body, is provided. Design considerations for the integration of single-axis force sensors above the wheel hubs are presented. Structural analysis of the rocker and bogie links is outlined. The cross-hill and uphill-downhill static stability of Kapvik is investigated. Load cell and joint position data from testing during obstacle negotiation and uphill operation are presented.

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JBIS - Journal of the British Interplanetary Society
Department of Mechanical and Aerospace Engineering

Setterfield, T. (Timothy), Frazier, C. (Cameron), & Ellery, A. (2014). Mechanical design and testing of an instrumented rocker-bogie mobility system for the Kapvik micro-rover. JBIS - Journal of the British Interplanetary Society, 67(3), 96–104.