Systematic Structural Optimization of a Next Generation Lunar Rover Chassis

Abstract

This research utilized topology and size optimization to optimize a lunar rover chassis in order to reduce structural mass while satisfying the required surface and launch vehicle loading criterion. Renewed interest in lunar exploration has provided an opportunity for Canada to participate in a Lunar Prospecting Mission in collaboration with NASA. Queen’s University, in collaboration with Neptec Design Group, has developed methodology to produce the structural design of a next generation lunar rover chassis using systematic design optimization techniques to minimize the structural mass of the chassis. Typical lightweight design can be achieved using lightweight materials, advanced manufacturing processes or systems, and design optimization. Due to the unique requirements for spacecraft, the proposed research is limited to specific materials and processes, therefore weight reduction is achieved exclusively through design optimization. The structural design was completed using a three stage design approach: Conceptual, Preliminary, and Detailed Design Stages. The Conceptual Design Stage developed chassis designs considering component layout and bounding box topology. The generated concepts were evaluated qualitatively to select the best candidates for design optimization. The Preliminary Design Stage utilized Hyperworks© Optistruct commercial software to complete topology optimization to optimize the chassis bounding box topology while considering lunar surface and launch vehicle loading. The topology optimization results were then used to create preliminary optimum designs. In the detailed design stage, size optimization with Optistruct was used to refine the preliminary design further to produce a final optimum design which had characterized mass and structural performance. All optimization work was constrained to satisfy displacement, stress, and natural frequency constraints. The final optimum design reduced the weight of the chassis by 38.7% when compared to the baseline design while satisfying all required loading scenarios. By current valuation, this mass reduction can be valued at approximately $24 million dollars [2] from the current cost per kg of transporting payload on the lunar surface. This research has shown that new methods can achieve substantial weight reductions in the structural design of spacecraft. Mass reduction of the magnitude found in this research stands to have significant benefits to the development of future space exploration programs.