A Rock-coring Campaign in an Analogue Environment:Performance, Lessons and Development

Harkness, Patrick; McRobb, Malcolm; Loh, Ying; Hyde, Mark; Lucas, Margaret

doi:10.2514/6.2014-4264

Cited by 2 publications

(3 citation statements)

References 8 publications

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“…The densities for these three types of rocks are similar but their porosities vary significantly which may cause the controlled drill tool to behave differently during percussive drilling. 30 [9] 38 [10] 40 [9] The RMS power in free air percussion is found to be around 20W, and a reference level of 30W is set to examine the performance of the drill in all three rocks. Additionally, drills will be conducted in the Blaxter sandstone at 25W, 30W (a duplicate test) and 35W to examine the effect of the reference level itself, and all tests are conducted both with and without rotation to allow the impact force applied to be measured.…”

Section: Performance Of Control Systemmentioning

confidence: 99%

A Motion Control System Design for an Ultrasonic Percussive Coring/Drilling Unit

Harkness

Timoney

et al. 2015

AIAA SPACE 2015 Conference and Exposition

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A prototype of a motion control system for an Ultrasonic Planetary Core Drill (UPCD) tool is presented. This system is designed to maintain a consistent dynamic behavior in the ultrasonic horn/free-mass/drill bit stack during ultrasonic-percussive drilling into a range of non-homogeneous rocks. The control system is a simple negative feedback loop which employs the output of the P100 control unit (manufactured by Sonic Systems Ltd) that powers the ultrasonic transducer, ensuring that the drill tool is advanced while a steady ultrasonic vibration level is maintained. This paper describes the mechanical design of the test rig, the control system design and an evaluation of its performance. Nomenclature u = control input s = sensor output r = reference e = error

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Section: Performance Of Control Systemmentioning

confidence: 99%

A Motion Control System Design for an Ultrasonic Percussive Coring/Drilling Unit

Harkness

Timoney

et al. 2015

AIAA SPACE 2015 Conference and Exposition

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“…The values are the eigenvalues of the distributed parameter model calculated in equation (8). The eigenvectors are the amplitude ratios between the 1 st and 2 nd stages of the 2-stage transducer and horn as measured experimentally at resonances.…”

Section: A 2-stage Transducer and Horn Modelmentioning

confidence: 99%

“…This permits rotation of the lance for the drill string assembly [7] and ensures that the teeth of the drill-bit impact different regions of the rock as drilling progresses. This ensures that the contact area remains small, the interface pressures remain correspondingly high, and the rate of progress is sufficiently rapid for planetary drilling [8].…”

Section: Introductionmentioning

confidence: 99%

A Parametric Study for the Design of an Optimized Ultrasonic Percussive Planetary Drill Tool

Harkness

Worrall

et al. 2017

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Abstract-Traditional rotary drilling for planetary rock sampling, in-situ analysis and sample return, is challenging because the axial force and holding torque requirements are not necessarily compatible with lightweight spacecraft architectures in low-gravity environments. This article seeks to optimize an ultrasonic-percussive drill tool to achieve rock penetration with lower reacted force requirements, with a strategic view towards building an Ultrasonic Planetary Core Drill (UPCD) device. The UPCD is a descendant of the Ultrasonic/Sonic Driller/Corer (USDC) technique. In these concepts, a transducer and horn (typically resonant at around 20kHz) is used to excite a toroidal free-mass which oscillates chaotically between the horn tip and drill base at lower frequencies (generally between 10Hz to 1kHz). This creates a series of stress pulses which are transferred through the drill-bit to the rock surface and, while the stress at the drill-bit tip/rock interface exceeds the compressive strength of the rock, cause fractures that result in fragmentation of the rock. This facilitates augering and downward progress. In order to ensure that the drill-bit tip delivers the greatest effective impulse (the time-integral of the drill-bit tip/rock pressure curve exceeding the strength of the rock), parameters such as the spring rates and the mass of the free-mass, drill-bit and transducer have been varied and compared in both computer simulation and in practical experiment. The most interesting findings, and those of particular relevance to deep drilling, indicate that increasing the mass of the drill-bit has a limited (or even positive) influence on the rate of effective impulse delivered.

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A Rock-coring Campaign in an Analogue Environment:Performance, Lessons and Development

Cited by 2 publications

References 8 publications

A Motion Control System Design for an Ultrasonic Percussive Coring/Drilling Unit

A Motion Control System Design for an Ultrasonic Percussive Coring/Drilling Unit

A Parametric Study for the Design of an Optimized Ultrasonic Percussive Planetary Drill Tool

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