Development of a robust mating system for use in the autonomous assembly of planetary drill strings

Timoney, R., Worrall, K. , Li, X. , Firstbrook, D. and Harkness, P. (2020) Development of a robust mating system for use in the autonomous assembly of planetary drill strings. Journal of Aerospace Engineering, 33(4), 04020040. (doi: 10.1061/(ASCE)AS.1943-5525.0001139)

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Abstract

Volume-constrained robotic missions seeking to obtain samples from beneath a planetary subsurface may wish to use a rigid drill string consisting of multiple, individual drill bit sections connected together, as opposed to a single, lengthy drill bit. To ensure that drill strings can be assembled and disassembled reliably, it is essential that a robust connection system be used. The authors propose a geometry that seeks to address the requirements of such a mating interface. The proposed solution is based on the bayonet interface, using L- and T-shaped so-called female grooves and male studs connected and disconnected together through a series of clockwise and counterclockwise rotations and single-point clamping events. This routine allows the transfer of both percussion through the drill string and torque in both directions of rotation, while permitting the accurate disconnection of individual drills bits at the required location. Sustained laboratory and field drilling operations suggest that bayonet-style connections offer a reliable solution to the problem of autonomous assembly and disassembly of drill strings in a planetary exploration setting. This paper discusses the development of such a connection system, based on the bayonet connection, which has been implemented in the overall architecture of the Ultrasonic Planetary Core Drill (UPCD). The design trade-off study, which sought to evaluate the use of the bayonet system in comparison with the more conventional screw thread interface, will be discussed, alongside experimental results from percussion transmission testing and drill string assembly testing.

Item Type:Articles
Additional Information:The Ultrasonic Planetary Core Drill consortium would like to acknowledge the financial support provided under the European Commission Framework 7 scheme.
Keywords:Planetary drilling, space systems, Mars exploration, lunar exploration, ISRU.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Firstbrook, David and Li, Dr Xuan and Timoney, Dr Ryan and Worrall, Dr Kevin and Harkness, Professor Patrick
Authors: Timoney, R., Worrall, K., Li, X., Firstbrook, D., and Harkness, P.
Subjects:T Technology > TJ Mechanical engineering and machinery
College/School:College of Science and Engineering > School of Engineering > Autonomous Systems and Connectivity
College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Journal of Aerospace Engineering
Publisher:American Society of Civil Engineers
ISSN:0893-1321
ISSN (Online):1943-5525
Published Online:08 May 2020
Copyright Holders:Copyright © 2020 American Society of Civil Engineers
First Published:First published in Journal of Aerospace Engineering 33(4):04020040
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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