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Low-Pressure Casting of Bulk Metallic Glasses for Gears and Other Applications

Applications include the automotive, aeronautics, aerospace, robotics, commercial, and military/defense industries. NASA’s Jet Propulsion Laboratory, Pasadena, California With the correct selection of composition, some bulk metallic glasses (BMGs) have been demonstrated that have excellent combinations of hardness, fracture toughness, and wear resistance so that their use in gears and gearboxes is a potentially commercially viable application. For BMGs to be used as a low-cost alternative to steel gears, rapid fabrication strategies are needed to cast the BMGs into net-shaped gears that require little or no post-casting machining prior to use. Die casting, suction casting, and other cold-mold casting techniques have been widely demonstrated for BMGs in the past, but the unique nature of gears precludes traditional techniques from being used in an optimal way.

Posted in: Briefs

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Lunar Materials Handling System

Lyndon B. Johnson Space Center, Houston, Texas A method was developed for transfer of lunar soil into and out of process equipment. The Lunar Materials Handling System (LMHS) conveys solids to a process vessel, provides a gas-tight seal, prevents seal contamination, and minimizes wear from abrasive particles. The LMHS increases equipment life and minimizes process losses, thereby increasing overall in-situ resource utilization (ISRU) leverage. The LMHS is based on a seal arrangement by which lunar or Mars regolith can be repeatedly introduced into, and removed from, reaction chambers operating under a wide range of conditions. An integrated LMHS was demonstrated during operation in a one-cubic-meter vacuum chamber using hydrogen reduction as an ISRU process demonstration platform.

Posted in: Briefs, TSP, Robotics

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Two-Dimensional Dropped Sensor Suite

The concept can be applied to gather data simultaneously from a number of locations that are too hazardous or inaccessible. NASA’s Jet Propulsion Laboratory, Pasadena, California There are locations that are either too hazardous to land and gather data, or not practical to land. Also, data may need to be gathered from multiple (tens to hundreds) locations (sometimes at once). This is not feasible with a single lander or rover. A single lander does not provide any redundancy in case the lander (or rover) is lost during landing, and due to high costs, is not amenable to landing at multiple locations.

Posted in: Briefs, TSP, Robotics

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Controlling Execution Sequence Using Tactile-Classification During Manipulation by a Humanoid Robot

Lyndon B. Johnson Space Center, Houston, Texas It is necessary to track system state during robotic manipulation. System state is defined to be manipulator and environment configuration. Without tracking, the robot is ignorant of the outcomes of its actions. State tracking enables the robot to respond to sub-task failures. Tracking system state is difficult for complex robots that incorporate hundreds of individual sensor signals. It is difficult to determine which signals are relevant and which are not, and to find low dimensional representations of system state.

Posted in: Briefs, Robotics

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Autonomous Guidance Algorithm to Auto-Pilot Spacecraft in the Vicinity of Primitive Celestial Bodies

Sequential convex programming is used. NASA’s Jet Propulsion Laboratory, Pasadena, California The dynamics in the vicinity of small bodies are highly nonlinear. Trajectory design in small-body environments requires accurate gravity and solar radiation pressure models to guarantee the satisfaction of spacecraft operational constraints such as thruster silent times, state, and control constraints. The G-PROX guidance algorithm generates fuel-optimal trajectories in the vicinity of asteroids and small bodies. The non-convexity in the control constraints is handled with the lossless convexification technique, which is a convex relaxation of the control constraints. G-PROX uses sequential convex programming and solves a convergent sequence of convex optimization problems generated via sequential linearization of both the dynamics and control bounds, synergistically combined with lossless convexification. The sequence of convex optimization problems converges to a locally optimal solution of the original nonlinear non-convex problem.

Posted in: Briefs, TSP, Robotics

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Safe Maritime Autonomous Path Planning in a High Sea State

Path planning for sea surface vehicles prevents capsizing and bow-diving in a high sea state. NASA’s Jet Propulsion Laboratory, Pasadena, California The goal of this work was to develop algorithms and software to generate a path that takes into account the direction of waves and wind as much as possible in order to mitigate potential damage to an autonomous underwater vehicle. A risk-based path planning algorithm to analyze real-world sensory data is combined with an enhanced sea surface model to generate a safe path.

Posted in: Briefs, TSP, Robotics

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Human Grasp Assist

A spinoff of the NASA/GM Robonaut 2 humanoid robot, this lightweight, motorized device can reduce or eliminate repetitive stresses to hands and arms. Lyndon B. Johnson Space Center, Houston, Texas Repetitive manual operations can degrade the work efficiency of a human operator over time, with the cumulative stresses of repetitive motion potentially affecting the resultant product quality and/or process efficiency. Accordingly, a lightweight, motorized device has been created that a user/operator may wear on a hand and forearm to augment the innate ability to flex his or her fingers, thumbs, and various connecting phalanges of a hand, thus optimizing the amount of grasping force applied to an object. The amount of augmenting tensile force provided by the motorized device may be controlled by the user via force-based contact sensors positioned at a distal end of each finger. As the operator exerts a grasping force on an object, a microcontroller, which may be embedded within (or connected to) a flexible band or strap portion of the device, automatically executes an algorithm to thereby calculate and/or select an optimal amount of augmenting tensile force required for executing the grasping action.

Posted in: Briefs, Robotics

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