1,370 research outputs found

    Performance enhancement of linear robotic workcell using DSP based control

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    Robotic Controllers have for the major part been computer implementations of PID or similar controllers. In this thesis DSP based control of a Robotic Workcell is presented. The control algorithms used with the DSP based controller are Input Shaping and also State Feedback. Input Shaping is a Feed Forward strategy for eliminating vibration under certain conditions. In this thesis Input Shaping is applied to the performance enhancement of a linear robot system. Although feedback control strategies offer higher accuracy and are much more robust, feedforward strategies offer possibilities for improving the response time. Input Shaping is successfully applied to the robot system. In particular the Zero Vibration (ZV), Zero Vibration and Derivative (ZVD), Extra Insensitive (El), and Optimal shapers are examined. The performance of these shapers is examined, with the system parameters subject to change. The performance of the Shapers is compared to a State Controller, for small steps. Since the command shaping is dependent on the measurement of the system damping (ζ) and the natural frequency (ωn) , performance degradation is observed if these parameters change significantly. By suitable design, this degradation can be restricted, so that useful performance is obtained from the system

    AERO & VISTA: Demonstrating HF Radio Interferometry with Vector Sensors

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    AERO (Auroral Emission Radio Observer) and VISTA (Vector Interferometry Space Technology using AERO) are recently selected NASA HTIDeS CubeSat missions for terrestrial auroral science and radio interferometric technology demonstration. The AERO and VISTA CubeSats both host vector sensing antenna systems providing advanced electromagnetic capabilities. Together, they will provide the first in-space demonstration of interferometric imaging, beamforming, and nulling using electromagnetic vector sensors at low frequencies (100 kHz –15 MHz). A key goal of the joint missions’ technology demonstration is to validate theoretical sensor performance modeling indicating that interferometric arrays composed of vector sensors will be able to maintain sensitivity even in the presence of terrestrial interference. If validated in flight, this capability would relax the requirement that space-based low frequency interferometers be placed far from the Earth (e.g. lunar orbit), and the closer communications range will significantly increase the data volume returned from space-based radio telescope systems. The two-spacecraft AERO+VISTA mission will address the auroral science goals of AERO (Erickson et al. 2018, SSC18) while adding three additional technology demonstration goals enabled by the second CubeSat, VISTA

    Technology 2000, volume 1

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    The purpose of the conference was to increase awareness of existing NASA developed technologies that are available for immediate use in the development of new products and processes, and to lay the groundwork for the effective utilization of emerging technologies. There were sessions on the following: Computer technology and software engineering; Human factors engineering and life sciences; Information and data management; Material sciences; Manufacturing and fabrication technology; Power, energy, and control systems; Robotics; Sensors and measurement technology; Artificial intelligence; Environmental technology; Optics and communications; and Superconductivity

    SPHERE: the exoplanet imager for the Very Large Telescope

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    Observations of circumstellar environments to look for the direct signal of exoplanets and the scattered light from disks has significant instrumental implications. In the past 15 years, major developments in adaptive optics, coronagraphy, optical manufacturing, wavefront sensing and data processing, together with a consistent global system analysis have enabled a new generation of high-contrast imagers and spectrographs on large ground-based telescopes with much better performance. One of the most productive is the Spectro-Polarimetic High contrast imager for Exoplanets REsearch (SPHERE) designed and built for the ESO Very Large Telescope (VLT) in Chile. SPHERE includes an extreme adaptive optics system, a highly stable common path interface, several types of coronagraphs and three science instruments. Two of them, the Integral Field Spectrograph (IFS) and the Infra-Red Dual-band Imager and Spectrograph (IRDIS), are designed to efficiently cover the near-infrared (NIR) range in a single observation for efficient young planet search. The third one, ZIMPOL, is designed for visible (VIR) polarimetric observation to look for the reflected light of exoplanets and the light scattered by debris disks. This suite of three science instruments enables to study circumstellar environments at unprecedented angular resolution both in the visible and the near-infrared. In this work, we present the complete instrument and its on-sky performance after 4 years of operations at the VLT.Comment: Final version accepted for publication in A&

    TransFormers for Extreme Environments: Projecting Favorable Micro-Environments Around Robots and Areas of Interest

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    Surviving Extreme Space Environments (EE) is one of NASAs Space Technology Grand Challenges; we propose a paradigm shift in addressing this challenge. TransFormers (TFs) transform a region of an extreme environment into a favorable micro-environment, projecting energy at the precise location where robots or humans operate. TFs often use shape transformation to control the energy projection

    Experimental and simulation study results for video landmark acquisition and tracking technology

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    A synopsis of related Earth observation technology is provided and includes surface-feature tracking, generic feature classification and landmark identification, and navigation by multicolor correlation. With the advent of the Space Shuttle era, the NASA role takes on new significance in that one can now conceive of dedicated Earth resources missions. Space Shuttle also provides a unique test bed for evaluating advanced sensor technology like that described in this report. As a result of this type of rationale, the FILE OSTA-1 Shuttle experiment, which grew out of the Video Landmark Acquisition and Tracking (VILAT) activity, was developed and is described in this report along with the relevant tradeoffs. In addition, a synopsis of FILE computer simulation activity is included. This synopsis relates to future required capabilities such as landmark registration, reacquisition, and tracking

    The NASA Spitzer Space Telescope

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    The National Aeronautics and Space Administration's Spitzer Space Telescope (formerly the Space Infrared Telescope Facility) is the fourth and final facility in the Great Observatories Program, joining Hubble Space Telescope (1990), the Compton Gamma-Ray Observatory (1991–2000), and the Chandra X-Ray Observatory (1999). Spitzer, with a sensitivity that is almost three orders of magnitude greater than that of any previous ground-based and space-based infrared observatory, is expected to revolutionize our understanding of the creation of the universe, the formation and evolution of primitive galaxies, the origin of stars and planets, and the chemical evolution of the universe. This review presents a brief overview of the scientific objectives and history of infrared astronomy. We discuss Spitzer's expected role in infrared astronomy for the new millennium. We describe pertinent details of the design, construction, launch, in-orbit checkout, and operations of the observatory and summarize some science highlights from the first two and a half years of Spitzer operations. More information about Spitzer can be found at http://spitzer.caltech.edu/

    COBE's search for structure in the Big Bang

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    The launch of Cosmic Background Explorer (COBE) and the definition of Earth Observing System (EOS) are two of the major events at NASA-Goddard. The three experiments contained in COBE (Differential Microwave Radiometer (DMR), Far Infrared Absolute Spectrophotometer (FIRAS), and Diffuse Infrared Background Experiment (DIRBE)) are very important in measuring the big bang. DMR measures the isotropy of the cosmic background (direction of the radiation). FIRAS looks at the spectrum over the whole sky, searching for deviations, and DIRBE operates in the infrared part of the spectrum gathering evidence of the earliest galaxy formation. By special techniques, the radiation coming from the solar system will be distinguished from that of extragalactic origin. Unique graphics will be used to represent the temperature of the emitting material. A cosmic event will be modeled of such importance that it will affect cosmological theory for generations to come. EOS will monitor changes in the Earth's geophysics during a whole solar color cycle

    Multi-object recognition and retrieval using Puma560 robot

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    The objective of the research described here is to develop efficient algorithm and software tools for multiobject recognition and retrieval. This research project addresses two major issues: The first issue is the identification of features and efficient methods for feature extraction which can completely describe an object. These features can be acquired using visual and ultra-sonic sensors. The second issue is the development of efficient algorithms for the retrieval of multi-objects based on their features; The methods and algorithms developed in this research are verified on a Unimation PUMA 560 robot. Non contact sensors (a vision and a range sensor) are employed for feature detection. The information from both sensors will be combined for feature extraction and feature mapping (sensor fusion). The sensors and the robot have been integrated for this purpose with a Pentium 133 Mhz Personal Computer

    Laboratory for Oceans

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    A review is made of the activities of the Laboratory for Oceans. The staff and the research activities are nearly evenly divided between engineering and scientific endeavors. The Laboratory contributes engineering design skills to aircraft and ground based experiments in terrestrial and atmospheric sciences in cooperation with scientists from labs in Earth sciences
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