On two arc-shaped sensor front noses for smaller axial resistance of mole

The mole is the probe device, using internal hammering mechanism to move downward by compaction of lunar soil in space exploration. In this paper, we propose convex and concave circular arc shape for sensor front nose of the hammer-driven mole. Afterwards, mechanics models are established between soil and mole with the two shapes of the sensor front nose respectively according to soil mechanics theory. Then, we deduce the approximate axial resistance equations of the mole and other parameters are considered to be constant in order to analyze the influence of the geometric parameters calibre-radius-head to axial resistance only. Besides, different of the two shapes are compared as well. What's more, the penetration of the mole with two shapes is simulated in EDEM software and the theoretical results are demonstrated by simulations.