Hybrid Additive Manufacturing of a Topologically Optimized, Modular Lattice Wheel for Terrain-Adaptive Mobility on Martian Surfaces

Mobility on the Martian surface poses complex challenges due to abrasive regolith, thermal cycling, low atmospheric pressure, and unpredictable terrain. To address these, this study presents the design, development, and validation of a hybrid-manufactured, terrain-adaptive Mars rover wheel. The final architecture integrates a CNC-machined titanium skeleton, a topology-optimized titanium lattice core fabricated via Laser Powder Bed Fusion (LPBF), and modular tread lugs constructed from flexible TPU using material extrusion. Each component is functionally partitioned to optimize structural integrity, impact absorption, and adaptability while ensuring repairability and manufacturability in both Earthbased and potential in-situ environments. A structured design process incorporating Quality Function Deployment (QFD), Design for Additive Manufacturing (DfAM), and lattice benchmarking led to the selection of the Octa-Hedroid lattice topology for the TPU tread lugs. Finite element analyses showed that this structure minimizes deflection (0.57 mm) and maintains low von Mises stress (15 MPa), while also promoting self-cleaning under Martian conditions due to its open, interconnected void geometry. Prototype fabrication at both 1:2 and 1:1 scales validated printability, modular assembly, and robustness under thermal, impact, and rolling resistance tests across multiple terrains. This work demonstrates how hybrid additive manufacturing can be strategically employed to meet planetary mobility needs through weightefficient, compliant, and serviceable designs. The modular lattice-based wheel provides a scalable and maintainable alternative to traditional rigid or mesh-based rover wheels, with significant promise for deployment in future Mars or other extra-terrestrial exploration missions.