Design and mechanical behavior evaluation of flexible metal wheel for crewed lunar rover

Abstract

In lunar exploration, flexible metal wheels are designed because the pneumatic tires and rigid wheels are not suitable for crewed lunar rovers. However, the load capacity of the existing flexible metal wheels cannot meet the requirements of heavy load. In this work, an innovative flexible metal wheel consisting of a single rim and twin carcasses was proposed. Firstly, the design method and the detailed structure of this wheel was described. In order to analyze its mechanical performance under different heavy loads, Finite Element Method simulations were conducted based on lunar environment. By vertical load simulation, sheet thickness (1.5 mm) was determined considering elasticity and stiffness. By tangential force and side force simulation, the maximum stresses were respectively obtained as 715.5 MPa and 433.2 MPa, which were less than the yield strength of the spring steel, thus no plastic deformation would occur. Impact simulation showed that the maximum stress of the flexible wheel on the rigid ground exceeded the yield strength of the spring steel, resulting in plastic deformation, while the maximum stress on the soft ground was less than the yield strength and no plastic deformation occurred. Based on these simulations, the flexible metal wheel was fabricated and tested to verify its strength, stiffness, and impact resistance. The wheel exhibited excellent load capacity and elasticity. Finally, the relationship between the test and simulation was analyzed. It is believed that the structure and design process of this new flexible metal wheel are valuable for the subsequent development of heavy flexible metal wheel.