Machining of a Rock Surface Shaver with a Piezoelectric Actuator for In situ Analysis in Lunar and Planetary Exploration

Abstract

Future lunar, planetary, and asteroid exploration will strongly demand in situ analysis of rock samples to obtain data related to various aspects. For precise composition analysis, a sample surface should be smoothed. In this paper, a surface shaver with a piezoelectric actuator is proposed and its machining performance in air is investigated. Shaving teeth are mounted at the ends of a pair of lever mechanisms. The device is pressed through four springs onto the workpiece with a linear actuator. When a sinusoidal voltage of 50 V_p-p and an offset voltage of 25 V were applied, the resonance frequency was 556 Hz and the unloaded amplitude of the shaving teeth was 0.77 mm_p-p. Basalt workpieces were machined for 10 min in air. Increasing the thrust force reduced the surface roughness, although the amount removed diminished with a further increase in the thrust force. The surface roughness varied widely not only due to the amount removed but also due to containing the pores.