Characteristics of tangential force acting on a single lug with translational motion in sandy soil

Lugs (i.e., grousers) are attached on the surface of wheels/tracks of mobile robots to enhance their traveling performance for accessing loose sandy terrains. The goal of this study is to experimentally confirm the effects of velocity, sinkage length, moving direction angle and inclination angle on the tangential force acting on an actively actuated lug. Moreover, based on comparison of the measured and the calculated values by using conventional tangential stress model, we confirmed that the force acting on lug-tip surface is not negligible. Subsequently, the tangential forces were measured with a series lugs with different thickness to show influences of the thickness further.