Special Coverage

Transducer-Actuator Systems for On-Machine Measurements and Automatic Part Alignment
Wide-Area Surveillance Using HD LWIR Uncooled Sensors
Heavy Lift Wing in Ground (WIG) Cargo Flying Boat
Technique Provides Security for Multi-Robot Systems
Bringing New Vision to Laser Material Processing Systems
NASA Tests Lasers’ Ability to Transmit Data from Space
Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines
Vibration Tables Shake Up Aerospace and Car Testing
Supercomputer Cooling System Uses Refrigerant to Replace Water

Piezoelectric Actuated Inchworm Motor (PAIM)

This linear piezoelectric actuator can operate at temperatures of 77 K or below.

NASA’s Jet Propulsion Laboratory, Pasadena, California

Conventional piezoelectric materials, such as PZTs, have reasonably high electromechanical coupling over 70%, and excellent performance at room temperature. However, their coupling factor (converting electrical to mechanical energy and vice versa) drops substantially at cryogenic temperatures, as the extrinsic contributions (domain wall motions) are almost frozen out below 130 K.

Posted in: Briefs, TSP, Energy, Fluid Handling, Motors & Drives, Electric motors
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Reactionless Drive Tube Sampling Device and Deployment Method

Springs and a counter-mass create a powerful and stable sampling device.

NASA’s Jet Propulsion Laboratory, Pasadena, California

A sampling device and a deployment method were developed that allow collection of a predefined sample volume from up to a predefined depth, precise sampling site selection, and low impact on the deploying spacecraft. This device is accelerated toward the sampled body, penetrates the surface, closes a door mechanism to retain the sample, and ejects a sampling tube with the sample inside. At the same time the drive tube is accelerated, a sacrificial reaction mass can be accelerated in the opposite direction and released in space to minimize the momentum impact on the spacecraft. The energy required to accelerate both objects is sourced locally, and can be a spring, cold gas, electric, or pyrotechnic. After the sample tube is ejected or extracted from the drive tube, it can be presented for analysis or placed in a sample return capsule.

Posted in: Briefs, TSP, Mechanical Components, Motors & Drives, Drilling, Test equipment and instrumentation, Spacecraft
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Micropulse Detonation Rocket Engine for Nano-Satellite Propulsion

Goddard Space Flight Center, Greenbelt, Maryland

An efficient propulsion system would use a micropulse detonation rocket engine (–PDRE) for nano-satellite maneuverability in space. Technical objectives are to design, build, and conduct a small detonation tube experiment in order to explore the feasibility of using –PDRE for propelling a nano-satellite. The plan is to study the requirement and predict the performance of –PDRE using various candidate propellants, as well as to conduct ground experiments, demonstrate useful thrust, and measure the specific impulse in a two-year time frame, so that a follow-on project can be proposed in a future NRI Center Innovation Fund.

Posted in: Briefs, TSP, Aeronautics, Motion Control, Propulsion, Automation, Propellants, Rocket engines, Satellites
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Propellant Loading Visualization Software

Monitoring of complex propulsion pressure systems has been simplified with colors.

Goddard Space Flight Center, Greenbelt, Maryland

Complex pressure systems are utilized during testing in the propulsion branch as well as during the propellant loading stage of a mission. Keeping track of the state of such a system becomes more difficult as the complexity of such a system increases, and when extensive procedures are being followed. A book-keeping system is needed for visualizing these complex systems.

Posted in: Briefs, TSP, Motion Control, Propulsion, Software, Computer software / hardware, Computer software and hardware, Imaging, Imaging and visualization, Computer software / hardware, Computer software and hardware, Imaging, Imaging and visualization, Propellants
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Robust Gimbal System for Small-Payload Manipulation

This is a low-mass, small-volume gimbal unit.

NASA’s Jet Propulsion Laboratory, Pasadena, California

Spaceborne gimbal systems are typically bulky with large footprints. Such a gimbal system may consist of a forked elevation stage rotating on top of the azimuth motor, and occupy a large volume. Mounting flexibility of such a system may be limited.

Posted in: Articles, Briefs, TSP, Mechanical Components, Motion Control, Motors & Drives, Materials handling, Mountings, Spacecraft
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Compact Active Vibration Control System

A highly directional actuator can be shaped so that it couples to the response of a flexible structure in the same manner as point sensors.

This innovation consists of an analog controller, diamond-shaped patch actuator, and point sensors (such as accelerometers). The actuator is designed to couple to the flexural response of the structure in the same manner as a group of point sensors. This results in a co-located transducer pair. The signals from all sensors are combined, filtered, and amplified within the analog controller. The resulting signal is then applied to the actuator, which generates a control force out-of-phase with the measured response. Because the transducers are co-located, the vibration control system is inherently robust to variations in properties of the underlying structure that is being controlled. This type of control system actively suppresses the vibration of a flexible structure using surface-mounted transducers without any external mechanical connections.

Posted in: Briefs, TSP, Motion Control, Electronic control systems, Electronic control systems, Vibration, Vibration
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Analyzing Rollover Stability of Capsules With Airbags Using LS-Dyna

This method interpolates data to predict the stability boundaries for a capsule on airbags.

As NASA moves towards developing technologies needed to implement its new Exploration program, studies conducted for Apollo in the 1960s to understand the rollover stability of capsules landing are being revisited. Although rigid body kinematics analyses of the rollover behavior of capsules on impact provided critical insight to the Apollo problem, extensive ground test programs were also used. For the new Orion spacecraft, airbag designs have improved sufficiently for NASA to consider their use to mitigate landing loads to ensure crew safety and to enable reusability of the capsule.

Posted in: Briefs, TSP, Motion Control, Stability control, Airbag systems, Spacecraft
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Test Fixture for Isolation of Vibration Shaker from G-Loading

Combined testing is possible in a controlled, calibrated, and repetitive manner.

The first step in implementing the capability to test sensitive launch vehicle instruments in a combined environment has been completed. The test environment consists of specific vibration spectra induced under sustained Gs, using NASTAR’s ATFS-400 centrifuge. Fixtures allow mounting of the device under test (DUT) to a vibrational shaker in a centrifuge for generating moderate G-loading (1.4 to 9G) such that the vibrational shaker’s capabilities are only slightly affected by the G-loads applied during testing. Two configurations were designed, with the vibrational load parallel to the G-loads, and with the vibration loads transverse (at right angles) to the G-loads. The results are extremely encouraging, and demonstrate the potential of the NASTAR centrifuge to perform this kind of combined testing in a controlled, calibrated, and repetitive manner.

Posted in: Briefs, TSP, Motion Control, Aircraft instruments, Aircraft instruments, Vibration, Vibration, Launch vehicles
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Probe Positioning System for Antenna Range

Three or more cables provide the desired positioning.

In situ measurements of antenna patterns on rovers in a simulated terrain are difficult to make with conventional antenna range techniques. The desired pattern data covers a hemisphere above the antenna of interest, which is close to the ground. This is incompatible with traditional measurements that place the antenna under test on a movable support that tilts and rotates.

Posted in: Briefs, TSP, Motion Control, Antennas, Sensors and actuators, Antennas, Sensors and actuators, Spacecraft
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Fluidic Actuators with No Moving Parts

Two new fluidic actuator designs were developed to control fluid flow in ways that will ultimately result in improved system performance and fuel efficiency in to improve the aerodynamic performance of a variety of vehicles. These flow control actuators, often referred to as fluidic oscillators or sweeping jet actuators, utilize the Coanda effect to generate spatially oscillating bursts (or jets). They can be embedded directly into a control surface (such as a wing or a turbine blade) to help reduce flow separation, increase lift, reduce drag, enhance mixing, or increase heat transfer. Recent studies show up to a 60% performance enhancement (such as increased lift or reduced drag) with fluidic actuators.

Posted in: Briefs, TSP, Motion Control, Sensors and actuators, Sensors and actuators, Aerodynamics
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