Analysis of Grouser Performance to Develop Guidelines for Design for Planetary Rovers

This paper addresses issues in the design of wheel grousers for planetary rovers. It has been shown in prior and related work that grousers on wheel rims can improve traveling performance of rovers on loose soils. However, the main focus of these studies, so far, has been limited to straight grousers and to straight line motion of the wheels. This work extends such studies to include chevron-shaped grousers and also sideslipping motions for cross-slope and steering maneuvers. We show that chevron-shaped grousers can increase tractive efficiency (the ratio of output to input work for the wheel), though only in relatively benign or low slip operations. We also show that grousers increase lateral forces during sideslip operations, improving performance on cross-slopes, but decreasing skid-steering efficiency. We demonstrate that an equation for appropriate grouser spacing, developed in prior work, remains consistent with sideslip operations. Based on these results, guidelines for grouser design are discussed for different operating conditions.