Mechanical analysis of a drum type wheel rolling on loose sandy soil

Based on pressure sinkage laws and shear stress-displacement relationships in terramechanics, a mathematical model was developed to describe the motion performance of a drum type wheel. This should improve design, motion control, and vehicle simulation for the lunar rover. After establishing quantitative relationships between motion performance, soil properties and wheel dimensions, the drum wheel was divided into many slim cylindrical wheels. When analyzing radial and tangential stress distributions under the wheel-soil interface, it was found that maximum radial stress occurs in front of bottom-dead-centre and shifts forward when increasing slip is taken into account. On the basis of parameter measurements of loose sandy soil, the relationship between shear modulus and contact pressure was introduced. For theoretical analysis, the value of shear modulus which corresponds to load exerted on the experiment wheel was obtained by defining the area of drum wheel-soil contact. Experimental results from a single-wheel testbed operated in loose sandy soil shows that this model for predicting drum wheel performance is reliable.