The ultrasonic/sonic anchor (U/S anchor) is an anchoring device that drills a hole for itself in rock, concrete, or other similar material. The U/S anchor is a recent addition to a series of related devices, the first of which were reported in “Ultrasonic/Sonic Drill/Corers With Integrated Sensors” (NPO-20856), NASA Tech Briefs, Vol. 25, No. 1 (January 2003), page 38. There are numerous potential uses for U/S anchors, especially in enabling walking robots and humans to climb steep rock faces for diverse purposes, including scientific exploration, recreational rock climbing, military maneuvers, and search and rescue.
In a typical prior related device, the sonic vibrations are generated with the help of upper and lower mass that is denoted the free mass because it is free to move axially through a limited range within the actuator/tool-bit assembly. In the U/S anchor, there are two free masses: one above and one below the lower tip of the horn (see figure). Each free mass bounces between hard stops at the limits of its range of motion at a sonic frequency. The impacts of the free masses on the hard stops create stress pulses that propagate along the horn, to and through the tool bit, to the tool-bit/rock interface. The rock becomes fractured when its ultimate strain is exceeded.
A major advantage of the U/S anchor (or of any device in this series) is that it is not necessary to apply a large axial force to make the tool bit advance into the drilled material. Similarly, during operation, only a small force suffices to extract the tool bit from the drilled hole. Hence, a human or robotic rock climber could easily insert and withdraw a U/S anchor at successive positions during traversal of a rock face.
This work was done by Yoseph Bar-Cohen and Stewart Sherrit of Caltech for NASA’s Jet Propulsion Laboratory.
This invention is owned by NASA, and a patent application has been filed. Inquiries concerning nonexclusive or exclusive license for its commercial development should be addressed to the Patent Counsel, NASA Management Office–JPL. Refer to NPO-40827.
This Brief includes a Technical Support Package (TSP).
Ultrasonic/Sonic Anchor
(reference NPO-40827) is currently available for download from the TSP library.
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Overview
The document presents a technical disclosure of a novel Ultrasonic/Sonic Anchor (U/S Anchor), designed for efficient anchoring and extraction in various applications, particularly in space exploration and rugged terrains. This innovative device operates using a unique ultrasonic/sonic actuation mechanism, allowing it to penetrate and extract from hard materials such as rocks, concrete, and stones with minimal axial load.
The U/S Anchor is based on the Ultrasonic/Sonic Driller/Corer (USDC) technology, which utilizes a piezoelectric stack and a horn for amplifying displacements. The design features a dual set of free masses that enable the anchor to function as both a penetrator and a self-extractor. The device is capable of generating stress pulses that fracture the material at the interface, facilitating secure anchoring while maintaining a low force requirement for extraction.
Key features of the U/S Anchor include its ability to be mounted and extracted with minimal axial forces, making it suitable for use in low-gravity environments, such as those found on other planets. This capability is crucial for NASA missions that involve in-situ exploration tasks, where reliable anchoring is essential for stability against environmental factors like wind. The document outlines potential applications for the U/S Anchor, including supporting legged and wheeled rovers, anchoring inflatable structures, and assisting astronauts in climbing steep surfaces.
The document also discusses the importance of the U/S Anchor in addressing specific challenges faced during space missions, such as the need for a lightweight, low-power anchoring solution that can operate effectively in harsh conditions. The U/S Anchor is envisioned to enhance the operational capabilities of various NASA platforms and could also have military and recreational applications, such as climbing walls and traversing difficult terrains.
In summary, the U/S Anchor represents a significant advancement in anchoring technology, combining innovative design with practical applications for both space exploration and terrestrial use. Its development reflects ongoing efforts to improve the efficiency and effectiveness of anchoring mechanisms in challenging environments.
