Special Coverage

NASA Supercomputer Simulations Reveal 'Noisy' Aerodynamics
Robotic Gripper Cleans Up Space Debris
Soft Robot “Walks” on Any Terrain
Defense Advanced Research Projects Agency
Using Microwaves to Produce High-Quality Graphene
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

Software for Designing Actively Controlled Structures

SMARTCOM is a computer program for the analysis and design of actively controlled “smart” structures. Typically, an actively controlled “smart” structure incorporates piezoelectric sensors and actuators that are used, in conjunction with an electrical control system, to damp vibrations. As is the case for other structures, the analysis and design of actively controlled “smart” structures is often best accomplished with the help of finite-element computer programs. Unfortunately, prior finite-element codes do not offer coupled analyses of the mechanical, electrical, and thermal properties of “smart”-structure materials. Also, they are not directly linked with control software, making it necessary to use separate finite-element and control programs to analyze controlled structures. Furthermore, the programs used heretofore to design “smart” structures do not offer capabilities for optimization or for probabilistic or fuzzy analysis.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Finite element analysis, Mathematical models, Electronic control systems, Sensors and actuators, Electronic control systems, Sensors and actuators, Smart materials, Vibration, Vibration

Magnetically Moved Trim Masses for Fine Position Control

Systems of caged trim masses manipulated by magnetic fields have been proposed for effecting fine control of the positions and/or orientations of spacecraft. The systems were conceived for use during observations by spaceborne interferometers, the component instruments of which (1) are located on multiple spacecraft flying in formation and (2) are required to be kept aligned with each other within narrow position and orientation tolerances. The proposed systems would make it possible to avoid the spurious effects generated by the spacecraft propulsion systems that would otherwise have to be used for fine position control; the spurious effects would include vibrations, exhaust, and flashes of light, which would be detrimental to the interferometric observations. Terrestrial versions of the proposed systems might be useful for fine horizontal positioning of delicate scientific instruments.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Flight control systems, Flight control systems, Spacecraft

New Technique Improves Cirrus Cloud Characterization

A new technique for retrieving cirrus properties from radiometric measurements at submillimeter wavelengths has been developed. The technique can accurately measure the amount of ice present in cirrus clouds, determine the median crystal size, and constrain crystal shape. The retrieval algorithm improves upon prior algorithms by also retrieving middle and upper tropospheric water-vapor profiles in concert with cloud properties. This joint-analysis method corrects for retrieval errors introduced by water vapor in and near the cloud.

Posted in: Briefs, TSP, Physical Sciences, Mathematical models, Radar, Radar, Humidity, Weather and climate

Maximum-Likelihood Template Matching

An improved algorithm for detecting gray-scale and binary templates in digitized images has been devised. The greatest difference between this algorithm and prior template-detecting algorithms stems from the measure used to determine the quality or degree of match between a template and given portion of an image. This measure is based on a maximum-likelihood formulation of the template- matching problem; this measure, and the matching performance obtained by use of it, are more robust than are those of prior template-matching algorithms, most of which utilize a sum-of-squared-differences measure. Other functions that the algorithm performs along with template matching include subpixel localization, estimation of uncertainty, and optimal selection of features. This algorithm is expected to be useful for detecting templates in digital images in a variety of applications, including recognition of objects, ranging by use of stereoscopic images, and tracking of moving objects or features. (For the purpose of tracking, features or objects recognized in an initial image could be used as templates for matching in subsequent images of the same scene.)

Posted in: Briefs, TSP, Information Sciences, Mathematical models, Imaging, Imaging and visualization, Imaging, Imaging and visualization, Performance upgrades

Fast Algorithms and Circuits for Quantum Wavelet Transforms

Fast algorithms and the first complete and efficient circuits for implementing two quantum wavelet transforms have been developed in theory. The significance of this development within the overall development of quantum computing is the following: In principle, the algorithms and circuits constitute instructions for implementing the transforms by use of primitive quantum gates; the circuits in this case are analogous to circuit-diagram-level descriptions of classical electronic circuits that perform logic functions.

Posted in: Briefs, TSP, Information Sciences, Mathematical models, Architecture, Integrated circuits, Architecture, Integrated circuits

Study of Inertial and Gravitational Masses of a Boson

A report presents a theoretical study of the relationship between the inertial mass (mi) and gravitational mass (mg) of a self-interacting neutral scalar boson in a heat bath. The question of whether these masses differ arises in modern physics. In quantum field theory, the mass of a particle appears as a parameter that, as a result of interaction with fields, is changed to a renormalizable, physically reliable value (mR). The interaction of a particle with fields also has a thermal character. Thus, a boson in a heat bath in a gravitational field gains an acceleration different from the gravitational acceleration. The study utilizes a simple approximate Lagrangian model that is well suited for analysis of temperature- and gravitation-related effects.

Posted in: Briefs, TSP, Physical Sciences, Mathematical models, Measurements, Thermal testing

Metal/Dielectric Color Filters for Flat Panel Displays

A report expands on the proposal described in “Low-Absorption Color Filters for Flat Panel Display Devices” (NPO-20435) NASA Tech Briefs, Vol. 23, No. 12 (December 1999), page 34. To recapitulate: The dye pixel color filters in a conventional liquid-crystal or other display device would be replaced with interference filters, which are less absorptive, and optics would be configured so that light reflected from the filters would be reused as illumination. The overall effect would be to increase brightness and efficiency. The present report adds specificity by proposing that the interference filters be of the type described in “Metal/Dielectric-Film Interference Color Filters” (NPO-20217), NASA Tech Briefs, Vol. 23, No. 2 (February 1999), page 70: Each filter would be made of three thin metal films interspersed with two thin dielectric films. In comparison with conventional multilayer all-dielectric filters, the proposed filters would contain fewer layers, and therefore could be fabricated more easily and at lower cost.

Posted in: Briefs, TSP, Physical Sciences, Displays, Displays, Product development, Fabrication, Metals

Multiphase-Flow Model of Fluidized-Bed Pyrolysis of Biomass

A report presents additional information about the subject matter of “Model of Pyrolysis of Biomass in a Fluidized- Bed Reactor” (NPO-20708) NASA Tech Briefs, Vol. 25, No. 6 (June 2001), page 59. The model is built on equations for the dynamics of three components — gas, sand, and biomass — partly by taking suitable ensemble averages of the coupled conservation equations for the gas, and for the biomass and sand particles. Equations for exchanges of mass, momentum, and energy between phases are included. Equations for transport of the solid phase are closed by use of separate distribution functions for sand and biomass particles. Interparticle collisions are described in the framework of the kinetic theory of dense gases, using inelastic- rigid-sphere models.

Posted in: Briefs, TSP, Physical Sciences, Mathematical models, Soils, Biomaterials, Gases

Vision-Only Operator Interface for a Robotic Manipulator

A system of electronic hardware and software has been developed as an experimental prototype of a visual interface between a human operator and a possibly remote one-arm anthropomorphic robotic manipulator. The system is denoted, more specifically, as a visiononly operator interface to emphasize that unlike some other operator interfaces, it does not include joysticks, forcefeedback devices, or other mechanical devices that could encumber the operator. The operator commands the robot by moving one of his or her arms; the operator receives feedback in the form of a live video image of the work space of the robot overlaid with a graphical model of the robot plus icons that warn of robot poses that should be avoided.

Posted in: Briefs, TSP, Electronics & Computers, Computer software / hardware, Computer software and hardware, Computer software / hardware, Computer software and hardware, Human machine interface (HMI), Displays, Displays, Robotics

Software for Geometric Calibration of Video Cameras

A software library and set of programs largely automate the geometric calibration of video cameras. Developed especially for robotic vision systems, this software generates the information needed to determine the three-dimensional (3D) positions of objects that appear in two- dimensional (2D) video images. Typically, the software can perform 2D-to-3D mappings with precision of 0.1 to 0.3 pixels. The software enables the creation, manipulation, and application of geometric models of camera lenses. The models are constructed semiautomatically from images of known calibration targets, and these models can be applied automatically to live images, thereby enabling robots to generate the position information needed for such robotic operations as manipulation of objects, mapping, and navigation. The software supports three main types of models: (1) linear (ordinarily suitable for fields of view narrower than about 30°), (2) radial lens distortion (typically suitable for fields of view ranging from 15° to 110° wide), and (3) fisheye lens distortion (typically suitable for fields of view wider than 90°). Camera models generated by this software have enabled the development of real-time, visionbased control systems on a variety of advanced civilian and military robots.

Posted in: Briefs, TSP, Software, Calibration, Mathematical models, Computer software / hardware, Computer software and hardware, Optics, Computer software / hardware, Computer software and hardware, Optics, Robotics

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