This work investigates the potential use of direct ultrasonic vibration as an aid to penetration of granular material. Compared with non-ultrasonic penetration, required forces have been observed to reduce by an order of magnitude. Similarly, total consumed power can be reduced by up to 27%, depending on the substrate and ultrasonic amplitude used. Tests were also carried out in high-gravity conditions, displaying a trend that suggests these benefits could be leveraged in lower gravity regimes.
This paper describes the effects of ultrasonically-assisted penetration of granular materials, in high gravity situations. The experimental rig, instrumented to obtain penetration force, rate and power both with and without ultrasonic assistance, was used to drive a penetrator into a granular material inside the ESA Large Diameter Centrifuge at accelerations of up to 10 g during early September 2015. Ultrasonic penetration proved to be most beneficial at lower levels of accelerations, reducing the required overhead weight by 80%, and the total power consumption by 27%.
This work presents the methods used and initial findings of the control of the model for an autonomous trenchless drilling device, with bioinspired worm-like locomotion. The model is validated using Inverse Simulation. The initial control is detailed with data from the simulation and experimental device.
This paper describes the effects of combining ultrasonic vibration with hammeraction style penetrators, such as the HP 3 probe on the InSight mission. By synchronizing short pulses of vibration with the impact of the hammer, the number of hammer strikes required to reach a specified depth was reduced by over a third in some cases, depending on the sand and amplitude of vibration used. Additional investigations looked at comparing the performance of pure hammering with pure pulsing, allowing recommendations for operational procedures if this technology were to be taken forward in the future.
The Ultrasonic Planetary Core Drill (UPCD), recently developed by a consortium of European partners with co-ordination from the University of Glasgow, is a planetary sample acquisition and caching systems testbed, recently field tested at Alexander Island, Antarctica.During the early development of the technology, laboratory-based drilling tests at ambient pressure, utilizing volatile-laden permafrost simulants, revealed the need for an enhancement of the existing control algorithm which autonomously governs the rate of progress of the drill through the terrain. Such modifications have been deemed essential if failure modes relating to re-solidification of unbound volatiles are to be avoided.In the preliminary development of this thermal control algorithm, multiple sensors have been utilized in order to enhance the reliability of the system. It is hoped that this sensor suite may also allow data concerning the thermal environment of the terrain to be exploited, improving the scientific return of the mission. This paper details the early progress made towards a robust thermal control system for the Ultrasonic Planetary Core Drill, featuring results of laboratory testing under ambient conditions in to targets consisting of simulated permafrost, pure ice and frozen saturated rock. Results from this series of preliminary tests show that, when required, the control algorithm developed has proven to be a useful addition to the UPCD control system through its ability to prevent freeze-in faults.
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