Design of Wheel Grouser Geometry with Reduced Sinkage for LEV-1 Lunar Rover
Masatsugu Otsuki, Kent Yoshikawa, Takao Maeda, Naoto Usami, Tetsuo Yoshimitsu
AI summary
Problem
Planetary rovers frequently experience excessive wheel sinkage and insufficient traction on loose regolith, which limits mobility and efficiency. Traditional grouser designs struggle to balance high draw-bar pull with minimal sinkage within strict size and mass constraints.
Approach
The authors extended Resistive Force Theory to mathematically model reaction forces for arbitrary grouser shapes, then optimized the grouser angle and length using simulations and single-wheel tests to maximize traction while minimizing sinkage.
Key results
- Formulated a generalized Resistive Force Theory model for arbitrary grouser geometries
- Identified a 90-degree tilted grouser orientation as optimal for maximizing draw-bar pull per sinkage
- Validated the design through single-wheel tests and Distinct Element Method simulations
- Successfully deployed and verified the optimized wheel on the LEV-1 lunar rover
Why it matters
Provides a practical, physics-based design framework for high-traction, low-sinkage rover wheels critical for future lunar and planetary exploration missions.
Abstract
Surface-mobile platforms have explored the moon and the red planet for nearly half century, providing a wealth of scientific data. However, surface mobility on planetary bodies remains a challenging task. In this paper, the formulation of reaction force by a grouser with a generalized geometry for a wheel of a planetary rover is presented, along with its verification through comparisons with the results by the conventional geometry. In a simulation study, the resistive force theory is applied to a general grouser geometry model. The study determines the impact of several parameters, particularly the grouser inclination, on draw-bar pull. The results obtained from the study suggest the formulation of a design for the grouser that is nearly optimal in its capacity to maximize the draw-bar pull per sinkage. We also apply the proposed geometry to the wheel on LEV-1, demonstrating that it works well in actual lunar operations.