453 research outputs found

    Technology for the Future: In-Space Technology Experiments Program, part 2

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    The purpose of the Office of Aeronautics and Space Technology (OAST) In-Space Technology Experiments Program In-STEP 1988 Workshop was to identify and prioritize technologies that are critical for future national space programs and require validation in the space environment, and review current NASA (In-Reach) and industry/ university (Out-Reach) experiments. A prioritized list of the critical technology needs was developed for the following eight disciplines: structures; environmental effects; power systems and thermal management; fluid management and propulsion systems; automation and robotics; sensors and information systems; in-space systems; and humans in space. This is part two of two parts and contains the critical technology presentations for the eight theme elements and a summary listing of critical space technology needs for each theme

    A Review of Cooperative Actuator and Sensor Systems Based on Dielectric Elastomer Transducers

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    This paper presents an overview of cooperative actuator and sensor systems based on dielectric elastomer (DE) transducers. A DE consists of a flexible capacitor made of a thin layer of soft dielectric material (e.g., acrylic, silicone) surrounded with a compliant electrode, which is able to work as an actuator or as a sensor. Features such as large deformation, high compliance, flexibility, energy efficiency, lightweight, self-sensing, and low cost make DE technology particularly attractive for the realization of mechatronic systems that are capable of performance not achievable with alternative technologies. If several DEs are arranged in an array-like configuration, new concepts of cooperative actuator/sensor systems can be enabled, in which novel applications and features are made possible by the synergistic operations among nearby elements. The goal of this paper is to review recent advances in the area of cooperative DE systems technology. After summarizing the basic operating principle of DE transducers, several applications of cooperative DE actuators and sensors from the recent literature are discussed, ranging from haptic interfaces and bio-inspired robots to micro-scale devices and tactile sensors. Finally, challenges and perspectives for the future development of cooperative DE systems are discussed

    Surgical Instruments based on flexible micro-electronics

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    This dissertation explores strategies to create micro-scale tools with integrated electronic and mechanical functionalities. Recently developed approaches to control the shape of flexible micro-structures are employed to fabricate micro-electronic instruments that embed components for sensing and actuation, aiming to expand the toolkit of minimally invasive surgery. This thesis proposes two distinct types of devices that might expand the boundaries of modern surgical interventions and enable new bio-medical applications. First, an electronically integrated micro-catheter is developed. Electronic components for sensing and actuation are embedded into the catheter wall through an alternative fabrication paradigm that takes advantage of a self-rolling polymeric thin-film system. With a diameter of only 0.1 mm, the catheter is capable of delivering fluids in a highly targeted fashion, comprises actuated opposing digits for the efficient manipulation of microscopic objects, and a magnetic sensor for navigation. Employing a specially conceived approach for position tracking, navigation with a high resolution below 0.1 mm is achieved. The fundamental functionalities and mechanical properties of this instrument are evaluated in artificial model environments and ex vivo tissues. The second development explores reshapeable micro-electronic devices. These systems integrate conductive polymer actuators and strain or magnetic sensors to adjust their shape through feedback-driven closed loop control and mechanically interact with their environment. Due to their inherent flexibility and integrated sensory capabilities, these devices are well suited to interface with and manipulate sensitive biological tissues, as demonstrated with an ex vivo nerve bundle, and may facilitate new interventions in neural surgery.:List of Abbreviations 1 Introduction 1.1 Motivation 1.2 Objectives and structure of this dissertation 2 Background 2.1 Tools for minimally invasive surgery 2.1.1 Catheters 2.1.2 Tools for robotic micro-surgery 2.1.3 Flexible electronics for smart surgical tools 2.2 Platforms for shapeable electronics 2.2.1 Shapeable polymer composites 2.2.2 Shapeable electronics 2.2.3 Soft actuators and manipulators 2.3 Sensors for position and shape feedback 2.3.1 Magnetic sensors for position and orientation measurements 2.3.2 Strain gauge sensors 3 Materials and Methods 3.1 Materials for shapeable electronics 3.1.1 Metal-organic sacrificial layer 3.1.2 Polyimide as reinforcing material 3.1.3 Swelling hydrogel for self assembly 3.1.4 Polypyrrole for flexible micro actuators 3.2 Device fabrication techniques 3.2.1 Photolithography 3.2.2 Electron beam deposition 3.2.3 Sputter deposition 3.2.4 Atomic layer deposition 3.2.5 Electro-polymerization of polypyrrole 3.3 Device characterization techniques 3.3.1 Kerr magnetometry 3.3.2 Electro-magnetic characterization of sensors 3.3.3 Electro-chemical analysis of polypyrrole 3.3.4 Preparation of model environments and materials 3.4 Sensor signal evaluation and processing 3.4.1 Signal processing 3.4.2 Cross correlation for phase analysis 3.4.3 PID feedback control 4 Electronically Integrated Self Assembled Micro Catheters 4.1 Design and Fabrication 4.1.1 Fabrication and self assembly 4.1.2 Features and design considerations 4.1.3 Electronic and fluidic connections 4.2 Integrated features and functionalities 4.2.1 Fluidic transport 4.2.2 Bending stability 4.2.3 Actuated micro manipulator 4.3 Magnetic position tracking 4.3.1 Integrated magnetic sensor 4.3.2 Position control with sensor feedback 4.3.3 Introduction of magnetic phase encoded tracking 4.3.4 Experimental realization 4.3.5 Simultaneous magnetic and ultrasound tracking 4.3.6 Discussion, limitations, and perspectives 5 Reshapeable Micro Electronic Devices 5.1 Design and fabrication 5.1.1 Estimation of optimal fabrication parameters 5.1.2 Device Fabrication 5.1.3 Control electronics and software 5.2 Performance of Actuators 5.2.1 Blocking force, speed, and durability 5.2.2 Curvature 5.3 Orientation control with magnetic sensors 5.3.1 Magnetic sensors on actuated device 5.3.2 Reference magnetic field 5.3.3 Feedback control 5.4 Shape control with integrated strain sensors 5.4.1 Strain gauge curvature sensors 5.4.2 Feedback control 5.4.3 Obstacle detection 5.5 Heterogenous integration with active electronics 5.5.1 Fabrication and properties of active matrices 5.5.2 Fabrication and operation of PPy actuators 5.5.3 Site selective actuation 6 Discussion and Outlook 6.1 Integrated self assembled catheters 6.1.1 Outlook 6.2 Reshapeable micro electronic devices 6.2.1 Outlook 7 Conclusion Appendix A1 Processing parameters for polymer stack layers A2 Derivation of magnetic phase profile in 3D Bibliography List of Figures and Tables Acknowledgements Theses List of Publication

    Johnson Space Center Research and Technology 1993 Annual Report

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    Johnson Space Center research and technology accomplishments during fiscal year 1993 are described and principle researchers and technologists are identified as contacts for further information. Each of the four sections gives a summary of overall progress in a major discipline, followed by detailed, illustrated descriptions of significant tasks. The four disciplines are Life Sciences, Human Support Technology, Solar Systems Sciences, and Space Systems Technology. The report is intended for technical and management audiences throughout the NASA and worldwide aerospace community. An index lists project titles, funding codes, and principal investigators

    Small business innovation research. Abstracts of completed 1987 phase 1 projects

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    Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

    Study of robotics systems applications to the space station program

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    Applications of robotics systems to potential uses of the Space Station as an assembly facility, and secondarily as a servicing facility, are considered. A typical robotics system mission is described along with the pertinent application guidelines and Space Station environmental assumptions utilized in developing the robotic task scenarios. A functional description of a supervised dual-robot space structure construction system is given, and four key areas of robotic technology are defined, described, and assessed. Alternate technologies for implementing the more routine space technology support subsystems that will be required to support the Space Station robotic systems in assembly and servicing tasks are briefly discussed. The environmental conditions impacting on the robotic configuration design and operation are reviewed

    Index to 1986 NASA Tech Briefs, volume 11, numbers 1-4

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    Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1986 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

    Research and technology

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    Significant research and technology activities at the Johnson Space Center (JSC) during Fiscal Year 1990 are reviewed. Research in human factors engineering, the Space Shuttle, the Space Station Freedom, space exploration and related topics are covered

    Crew station design

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