Tube transfer using the sampling arm for Mars sample caching

Abstract

A sample acquisition and caching architecture has been developed for the proposed Mars 2020 mission that acquires samples directly into sample tubes in coring bits. Sample tubes are inserted and removed from the bits, seals are inserted into the tubes, and the tubes are placed in the sample canister. This paper describes initial algorithms, implementation, and test results where sample tube transfer operations are performed using the sampling arm where the tube gripper is on the arm turret with the sampling tool. The testbed utilizes a robotic arm with harmonic drives in the actuators which then provide an arm with low backlash and high resolution of motion. A six-axis force-torque sensor provides force feedback for the tube transfer operations. The results show that the tube transfer operations can be done robustly using the existing testbed robotic arm and caching hardware. Future work is described which will investigate the effects on robustness of the tube transfer with reduced capability robotic arm and force sensing.