267,674 research outputs found

    Hand Held Device for Wireless Powering and Interrogation of Biomems Sensors and Actuators

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    A compact, hand-held device for wireless powering, interrogation and data retrieval from at least one implanted sensor. The hand-held device includes an antenna for powering an implanted sensor and for receiving data from the implanted sensor to the hand-held device for at least one of storage, display or analysis. The hand-held device establishes electromagnetic coupling with a low radiating radio frequency power inductor in the implanted sensor at a predefined separation and the antenna geometry allows for the antenna to power, interrogate and retrieve data from the implanted sensor without strapping the hand-held device to a human body housing the implanted sensor The hand-held device optionally allows for activation of the implanted sensor only during interrogation and data retrieval

    DESIGN AND ANALYSIS OF A 3D-PRINTED, THERMOPLASTIC ELASTOMER (TPE) SPRING ELEMENT FOR USE IN CORRECTIVE HAND ORTHOTICS

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    This thesis proposes an algorithm that determine the geometry of 3D-printed, custom-designed spring element bands made of thermoplastic elastomer (TPE) for use in a wearable orthotic device to aid in the physical therapy of a human hand exhibiting spasticity after stroke. Each finger of the hand is modeled as a mechanical system consisting of a triple-rod pendulum with nonlinear stiffness at each joint and forces applied at the attachment point of each flexor muscle. The system is assumed quasi-static, which leads to a torque balance between the flexor tendons in the hand, joint stiffness and the design force applied to the fingertip by the 3D-printed spring element. To better understand material properties of the spring element’s material, several tests are performed on TPE specimens printed with different infill geometries, including tensile tests and cyclic loading tests. The data and stress-strain curves for each geometry type are presented, which yield a nonlinear relationship between stress and strain as well as apparent hysteresis. Polynomial curves are used to fit the data, which allows for the band geometry to be designed. A hypothetical hand is presented along with how input measurements might be taken for the algorithm. The inputs are entered into the algorithm, and the geometry of the bands for each finger are generated. Results are discussed, and future work is noted, providing a means for the design of a customized orthotic device

    Impact of Coupled Resonator Geometry on Silicon-on Insulator Wavelength Filter Characteristics

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    We have analyzed and discussed the issues arising in the design of Silicon - on - Insulator (SOI) wavelength filters with different types of device geometry. Microring and microdisk geometries have been chosen as the device configurations and in order to demonstrate the device performance and potential, Free Spectral Range (FSR), and Q-factor values are computed. Studies of the transmittance characteristics are carried out using Finite- Difference Time-Domain (FDTD) methods by RSOFT Software. Results show that the microring-based wavelength filter has a FSR of 1.4 THz and a Q-factor value of 486. On the other hand,the microdisk based filter has a broader FSR with slightly smaller Q-factor

    A Multi-Robot Cooperation Framework for Sewing Personalized Stent Grafts

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    This paper presents a multi-robot system for manufacturing personalized medical stent grafts. The proposed system adopts a modular design, which includes: a (personalized) mandrel module, a bimanual sewing module, and a vision module. The mandrel module incorporates the personalized geometry of patients, while the bimanual sewing module adopts a learning-by-demonstration approach to transfer human hand-sewing skills to the robots. The human demonstrations were firstly observed by the vision module and then encoded using a statistical model to generate the reference motion trajectories. During autonomous robot sewing, the vision module plays the role of coordinating multi-robot collaboration. Experiment results show that the robots can adapt to generalized stent designs. The proposed system can also be used for other manipulation tasks, especially for flexible production of customized products and where bimanual or multi-robot cooperation is required.Comment: 10 pages, 12 figures, accepted by IEEE Transactions on Industrial Informatics, Key words: modularity, medical device customization, multi-robot system, robot learning, visual servoing, robot sewin

    A Multi-Robot Cooperation Framework for Sewing Personalized Stent Grafts

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    This paper presents a multi-robot system for manufacturing personalized medical stent grafts. The proposed system adopts a modular design, which includes: a (personalized) mandrel module, a bimanual sewing module, and a vision module. The mandrel module incorporates the personalized geometry of patients, while the bimanual sewing module adopts a learning-by-demonstration approach to transfer human hand-sewing skills to the robots. The human demonstrations were firstly observed by the vision module and then encoded using a statistical model to generate the reference motion trajectories. During autonomous robot sewing, the vision module plays the role of coordinating multi-robot collaboration. Experiment results show that the robots can adapt to generalized stent designs. The proposed system can also be used for other manipulation tasks, especially for flexible production of customized products and where bimanual or multi-robot cooperation is required.Comment: 10 pages, 12 figures, accepted by IEEE Transactions on Industrial Informatics, Key words: modularity, medical device customization, multi-robot system, robot learning, visual servoing, robot sewin

    Hand geometry recognition: an approach for closed and separated fingers

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    Hand geometry has been a biometric trait that has attracted attention from several researchers. This stems from the fact that it is less intrusive and could be captured without contact with the acquisition device. Its application ranges from forensic examination to basic authentication use. However, restrictions in hand placement have proven to be one of its challenges. Users are either instructed to keep their fingers separate or closed during capture. Hence, this paper presents an approach to hand geometry using finger measurements that considers both closed and separate fingers. The system starts by cropping out the finger section of the hand and then resizing the cropped fingers. 20 distances were extracted from each finger in both separate and closed finger images. A comparison was made between Manhattan distance and Euclidean distance for features extraction. The support vector machine (SVM) was used for classification. The result showed a better result for Euclidean distance with a false acceptance ratio (FAR) of 0.6 and a false rejection ratio (FRR) of 1.2

    Optimization of Integrated Transistors for Very High Frequency DC-DC Converters

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    This paper presents a method to optimize integrated lateral double-diffused MOSFET transistors for use in very high frequency (VHF, 30-300 MHz) dc-dc converters. A transistor model valid at VHF switching frequencies is developed. Device parameters are related to layout geometry and the resulting layout versus loss tradeoffs are illustrated. A method of finding an optimal layout for a given converter application is developed and experimentally verified in a 50-MHz converter, resulting in a 54% reduction in power loss over a hand-optimized device. It is further demonstrated that hot-carrier limits on device safe operating area may be relaxed under soft switching, yielding significant further loss reduction. A device fabricated with 3-μm gate length in 20-V design rules is validated at 35 V, offering reduced parasitic resistance and capacitance, as compared to the 5.5-μm device. Compared to the original design, loss is up to 75% lower in the example application

    Microgeometry capture using an elastomeric sensor

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    We describe a system for capturing microscopic surface geometry. The system extends the retrographic sensor [Johnson and Adelson 2009] to the microscopic domain, demonstrating spatial resolution as small as 2 microns. In contrast to existing microgeometry capture techniques, the system is not affected by the optical characteristics of the surface being measured---it captures the same geometry whether the object is matte, glossy, or transparent. In addition, the hardware design allows for a variety of form factors, including a hand-held device that can be used to capture high-resolution surface geometry in the field. We achieve these results with a combination of improved sensor materials, illumination design, and reconstruction algorithm, as compared to the original sensor of Johnson and Adelson [2009].National Science Foundation (U.S.) (Grant 0739255)National Institutes of Health (U.S.) (Contract 1-R01-EY019292-01
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