Motion Control

Analyzing Rollover Stability of Capsules With Airbags Using LS-Dyna

This method interpolates data to predict the stability boundaries for a capsule on airbags. Langley Research Center, Hampton, Virginia 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

Read More >>

Test Fixture for Isolation of Vibration Shaker from G-Loading

Combined testing is possible in a controlled, calibrated, and repetitive manner. John F. Kennedy Space Center, Florida 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

Read More >>

Rotary Series Elastic Actuator

The actuator provides motion and sensing for the degrees of freedom in the upper arm of a dexterous humanoid robot. Lyndon B. Johnson Space Center, Houston, Texas In order to perform human-like movement, an actuator is placed at each degree of freedom (DOF) in a humanoid robot. Additionally, these actuators must be packaged in an arrangement that approximates human structure and appearance. In this innovation, a rotary actuator assembly incorporates a brushless DC motor, a gear reduction, a variety of sensors, and a custom planar torsion spring to provide motive force, passive compliance, and torque sensing within an anthropomorphic package. The actuator, in various size scales, was designed for the humanoid robot described in “Dexterous Humanoid Robot,” (MSC-24739), NASA Tech Briefs, Vol. 38, No. 6 (June 2014), p. 52.

Posted in: Briefs, Motion Control

Read More >>

High-Temperature Actuators for Aircraft Propulsion Systems

Future “more electric aircraft” (MEA) will require electric actuation systems for control surfaces and engine controls. Electric motors, drive electronics, and mechanisms are essential elements of aircraft actuation in MEAs that incorporate Electro-Magnetic Actuators (EMAs). High-temperature environments experienced in aircraft applications place demands on actuator components, materials, and insulation systems that dictate the use of new technologies and materials.

Posted in: Articles, Motion Control

Read More >>

Probe Positioning System for Antenna Range

Three or more cables provide the desired positioning. NASA’s Jet Propulsion Laboratory, Pasadena, California 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

Read More >>

Fluidic Actuators with No Moving Parts

Langley Research Center, Hampton, Virginia 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

Read More >>

Designing a Multi-Segmented Robot for Hull Climbing

The Multi-segmented Magnetic Ro bot (MSMR) project addresses a capability gap in the intelligence, surveillance, and reconnaissance needs of the U.S. Navy visit, board, search, and seizure (VBSS); Navy SEALs; and Marine Force Reconnaissance teams. A segmented robotic platform with magnetic wheels and a minimal acoustic signature was developed that can navigate the hull, tanks, and passageways of a ship. The goal was to provide effective climbing and turning ability over and within a ferrous hull that typically features plumbing, protrusions, and indentations such as weld seams where hull plating meets. Such a robot will be able to climb the hull of a ship, provide covert perch-and-stare surveillance of the deck area, and wirelessly transmit audio/video before a search team boards. The technology is also promising for inspection of tanks, and dangerous or hard-to-reach passageways and voids in maritime vessels.

Posted in: Articles, Motion Control

Read More >>

White Papers

A Brief History of Modern Digital Shaker Controllers
Sponsored by Crystal Instruments
Electropolishing for Hydraulics and Pneumatics
Sponsored by Able Electropolishing
Adhesion Reduction of Semiconductor Dicing Tape
Sponsored by Excelitas
What is Wiring Synthesis?
Sponsored by Mentor Graphics
Protecting the Sky
Sponsored by Rohde and Schwarz AD
Customized Masking Solutions Don’t Require Customized Masks
Sponsored by Dymax

White Papers Sponsored By:

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.