Drilling states monitoring for a planetary drilling & coring testbed (PDCT): Method and design

Abstract

Drilling & coring has been selected as an effective method of acquiring soil sample in robotic planetary explorations. To avoid serious overload faults, drilling states should be monitored online and be tuned in a reasonable range. Herein, a novel flexible tube coring (FTC) method is adopted in China lunar exploration mission. To verify the proposed FTC method and acquire useful drilling states for online control, a planetary drilling & coring testbed (PDCT) was developed. The flowing states of lunar regolith are accurately acquired by applying a camera to calculate the volume of removed cuttings and by utilizing an ultrasonic sensor into the hollow auger to monitor the state of coring soil. Besides, drilling loads are acquired by a F/T sensor installed at the bottom of soil container. Experiments in one typical lunar regolith simulant show that the designed PDCT can be used to conduct ground tests for optimizing drill tool's structure and control strategy.