Tech Briefs

Workspace-Safe Operation of a Force- or Impedance-Controlled Robot

This technology can be used for automatic control of a robot that may come into contact with an object or operator in its workspace. Lyndon B. Johnson Space Center, Houston, Texas Precise motion control of a robot by controlling its various robotic manipulators may be organized by the required level of task specification. The levels include object-level control, which describes the ability to control the behavior of an object held in a single or a cooperative grasp of the robot; end-effector control, which is control of the various manipulators such as robotic fingers and thumbs; and joint-level control. Collectively, the various control levels achieve the required mobility, dexterity, and work task-related functionality.

Posted in: Mechanics, Mechanical Components, Briefs, TSP

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Cryogenic Mixing Pump with No Moving Parts

The pump is self-priming and can efficiently pump two-phase fluid. John H. Glenn Research Center, Cleveland, Ohio Refueling spacecraft in space offers tremendous benefits for increased payload capacity and reduced launch cost, but the problem of thermal stratification in long-term storage tanks presents a key challenge. To meet this challenge, a reliable, compact, lightweight, and efficient cryogenic mixing pump was developed with no moving parts. The pump uses an innovative thermodynamic process to generate fluid jets to promote fluid mixing. This thermodynamic process eliminates moving parts to generate pumping action. Inherent to its design, the pump is self-priming and can efficiently pump two-phase fluid. The device will significantly enhance the reliability of pressure control systems for storage tanks.

Posted in: Mechanics, Mechanical Components, Briefs, TSP

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Seal Design Feature for Redundancy Verification

The technology may be of interest to designers of high-altitude aircraft and submarine vessels. Lyndon B. Johnson Space Center, Houston, Texas NASA has requirements for redundant seals to protect human-occupied cabin atmospheres, as well as fluid and gas systems in space vehicles exposed to the harsh environments. Comparable requirements have been passed down to the International Space Station (ISS) Program, and are now levied on the Orion Multi-Purpose Crew Vehicle (MPCV).

Posted in: Mechanics, Mechanical Components, Briefs

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Dexterous Humanoid Robot

This robot can replace human workers in dangerous, life-threatening conditions. Lyndon B. Johnson Space Center, Houston, Texas A humanoid robot has been created that includes a torso, a pair of arms, a neck, and a head. The torso extends along a primary axis and presents a pair of shoulders. The pair of arms movably extends from the shoulders. Each of the arms is fully jointed. The neck movably extends from the torso along the primary axis, and has at least one neck joint. The head movably extends from the neck along the primary axis. The head has at least one head joint. The shoulders are canted toward one another at a shrug angle that is defined between each of the shoulders such that a workspace is defined between the shoulders.

Posted in: Mechanics, Mechanical Components, Briefs

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Tethered Vehicle Control and Tracking System

Kite-like wind energy generation systems can power a generator on the ground. Langley Research Center, Hampton, Virginia This innovation can control the flight of a tethered vehicle, in an airborne wind energy (AWE) generation system, through the use of a pan-tilt platform and a visible spectrum digital camera, combined with tracking and control software running on a standard PC.

Posted in: Mechanics, Mechanical Components, Briefs, TSP

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Lunar Organic Waste Reformer

Possible applications also include conversion of terrestrial organic wastes into fuel for power generation or into feedstock for chemical manufacture. John H. Glenn Research Center, Cleveland, Ohio The Lunar Organic Waste Reformer (LOWR) is a novel technology to convert organic wastes from human space exploration outposts into useful propellant constituents. The LOWR meets NASA’s Trash to Supply Gas (TtSG) objective under the Advanced Exploration Systems Logistics Reduction and Repurposing project by integrating steam reformation, methanation, and electrolysis to convert organic waste into methane and oxygen products. At reformer temperatures above 700 °C, oxygenated steam reacts with organic matter to produce a gas mixture largely composed of hydrogen, carbon monoxide, and carbon dioxide. After condensing and removing excess water, the reformer exhaust gases are fed to a catalytic Sabatier reactor where they are combined with supplemental hydrogen at 350 to 500 °C to produce methane and water. The methane product can be liquefied for storage.

Posted in: Physical Sciences, Briefs

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Digital Laser Frequency Stabilization via Cavity Locking Employing Low-Frequency Direct Modulation

Direct modulation reduces complexity, volume, and mass. NASA’s Jet Propulsion Laboratory, Pasadena, California This project’s goal was to simplify laser frequency stabilization. A simpler system will have many benefits, including reduction of power consumption, complexity, volume, mass, and risk of failure. To implement the Pound-Drever-Hall (PDH) technique requires both RF modulation and demodulation electronics, including an electro-optic modulator, a photoreceiver of sufficient bandwidth to detect the RF modulation fields, demodulation electronics of sufficient bandwidth, and an RF function generator. For a space mission, this equipment can be costly and power-hungry, in addition to the difficulty of being rated to operate in the harsh space environment.

Posted in: Physical Sciences, Briefs, TSP

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