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Pulse-Echo Probe Mounting Fixture for Blind Alignment on Pipes

This technology enables an effective, real-time, in-service health monitoring system for steam pipes. NASA’s Jet Propulsion Laboratory, Pasadena, California The probe and its mounting fixture are critical parts of the health monitoring of steam pipes. A high-temperature, piezoelectric transducer generates and receives ultrasonic waves, and the probe has to transmit the wave normal to the pipe surface. The mounting fixture is designed to allow for alignment of the probe even without a reference reflection, and thus enables blind alignment. In order to allow aligning of the probe normal to the surface of potential water condensation, and to secure intimate contact to the pipe surface, a novel mounting fixture was conceived and developed.

Posted in: Briefs, TSP

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Zero-Gravity Mobile Robot Using ON/OFF Adhesive Pads and Inchworm Mechanism

The robot has applications in military reconnaissance, and as a commercial toy. NASA’s Jet Propulsion Laboratory, Pasadena, California Inspection of the International Space Station and other manmade objects in space is difficult because of the microgravity environment. Robots are a promising approach to accomplish these inspection tasks and later repairs, but must be able to maneuver across the surfaces. Because there is no gravity, the robot is at high risk of floating away, necessitating grippers that can adhere to the surface and resist the forces and torques of inspecting and moving on the structure.

Posted in: Briefs

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Passive Mechanism for Maintaining Tension at a Spool to Within a Given Window

This innovation can be used with a vehicle, crane, winch, or boat, or for rock climbing, water skiing, and parasailing. NASA’s Jet Propulsion Laboratory, Pasadena, California During any winding or unwinding action, a tether may experience unexpected changes in tension. For example, the load being wound could become stuck and stop moving, causing the tension in the line to suddenly become extremely high. Alternatively, the load could slip, causing a lack of tension, or slack, in the line. Both of these scenarios can be harmful to neatly winding a spool in a tightly packed pattern. Excessive tension can cause one layer of line to become lodged in a layer below it and jammed. Too low of tension can cause the line on the spool to partially unravel and cause disorganized spooling. A novel mechanism utilizes the tension in the line and springs to hold a pulley between friction pads and a ratcheting mechanism to keep the tension at the spool within a particular window.

Posted in: Briefs, TSP

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Aluminum Gas Tungsten Arc Orbital Tube Welding

Orbital tube butt welding could be performed on aluminum tubes. NASA’s Jet Propulsion Laboratory, Pasadena, California JPL has been hand-welding aluminum tubing for decades in support of flight programs and ground support equipment, including thermal plates and shrouds. This hand-welding process is time-consuming, cumbersome, difficult, and unreliable in terms of repeatability and success, which leads to leaks, rework, and cost increase. Socket-style meltdown welds are difficult to inspect via traditional nondestructive evaluation (NDE) methods (radiography) since by design, there is always an inherent highstress point in the joint.

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Contact State Estimation for Multi-Finger Robot Hands Using Particle Filters

This method identifies the location, orientation, and shape of an object touched by a robot hand. Lyndon B. Johnson Space Center, Houston, Texas A method, using a particle filter, has been created for identifying the location, orientation, and shape of an object that a robot hand touches. An appropriate motion model has been defined that characterizes the motion of the robot hand as it moves relative to an object. The measurement model also estimates the likelihood of an observation of contact position, velocity, and tactile sensor information given handobject states, and is approximated analytically based on a geometric model, or on a corpus of training data. In either case, the measurement model distribution is encoded as a Gaussian, or using radial basis functions.

Posted in: Briefs, Machinery & Automation, Robotics

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Tendon-Driven Finger, Wrist, and Thumb Actuation System

This mini-manipulator for use in a humanoid robot system has size, strength, and dexterity comparable to that of a human. Lyndon B. Johnson Space Center, Houston, Texas The Robonaut 2 (R2) Dexterous Robot is the result of an effort to build a two-armed, ten-fingered humanoid robot torso capable of assembly work. This invention concerns a multi-fingered hand, and is composed of several parts. One is a tendon-driven, four-link, four-degree-of-freedom robotic thumb. Another is an extrinsic actuation system for tendon-driven fingers. The final part is a wrist mechanism with a large range of motion capable of high strength and speed while maintaining human wrist range of motion. The wrist provides pass-through capability for extrinsic hand actuation.

Posted in: Briefs, Machinery & Automation, Robotics

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Visual-Aided Inertial Navigation for Computationally Constrained Aerial Vehicles

System tracks points and edges, and previous vehicle poses. NASA’s Jet Propulsion Laboratory, Pasadena, California Micro aerial vehicles (MAVs) are lightweight, highly dynamic vehicles with limited payload, sensing, and computation capabilities. There is significant interest to automate MAVs for military surveillance, reconnaissance, and search-and-rescue missions. The current state of the art in MAV control utilizes an external system of cameras or other sensors to localize the vehicle during flight. Precise MAV localization using onboard computing and sensing resources is required for missions in unknown indoor and outdoor environments. In general MAVs may only operate using a low-performance inertial measurement unit and a single camera, with use of other sensors such as GPS or altimeters being limited by payload or environmental constraints.

Posted in: Briefs, Machinery & Automation, Robotics

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