60 research outputs found

    Coat Weight Predictions on the Cylindrical Laboratory Coater

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    Paper Coating attempts to create a smooth and even surface for improved optical and printing sheet performance. Trials were conducted using a blade application on a Cylindrical Laboratory Coater. Two different blade extensions were analyzed. These extensions were key variables that influenced blade forces. Currently, to achieve a range of coat weights on a sheet, only the trial and error method is performed during a run. The future goal in mind was to have a computer simulation that could make predictions of coat weights without performing the actual trial. This study was conducted to lay the groundwork for future analysis in hope of achieving this long range goal. A modeling technique was used to relate actual data to predictive data. From this technique, a positive correlation existed between actual data and modeling expectations. The best correlation was due to highly constrained geometries resulting from high run-in settings over the small blade extension. For future study, it is quite possible to establish a computer simulation technique, but it would have to be paper substrate specific and require numerous trials to eliminate all deviations

    Tracking 3-D Rotations with the Quaternion Bingham Filter

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    A deterministic method for sequential estimation of 3-D rotations is presented. The Bingham distribution is used to represent uncertainty directly on the unit quaternion hypersphere. Quaternions avoid the degeneracies of other 3-D orientation representations, while the Bingham distribution allows tracking of large-error (high-entropy) rotational distributions. Experimental comparison to a leading EKF-based filtering approach on both synthetic signals and a ball-tracking dataset shows that the Quaternion Bingham Filter (QBF) has lower tracking error than the EKF, particularly when the state is highly dynamic. We present two versions of the QBF, suitable for tracking the state of first- and second-order rotating dynamical systems

    Probabilistic procrustean models for shape recognition with an application to robotic grasping

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (p. 92-98).Robot manipulators largely rely on complete knowledge of object geometry in order to plan their motion and compute successful grasps. If an object is fully in view, the object geometry can be inferred from sensor data and a grasp computed directly. If the object is occluded by other entities in the scene, manipulations based on the visible part of the object may fail; to compensate, object recognition is often used to identify the location of the object and compute the grasp from a prior model. However, new instances of a known class of objects may vary from the prior model, and known objects may appear in novel configurations if they are not perfectly rigid. As a result, manipulation can pose a substantial modeling challenge when objects are not fully in view. In this thesis, we will attempt to model the shapes of objects in a way that is robust to both deformations and occlusions. In addition, we will develop a model that allows us to recover the hidden parts of occluded objects (shape completion), and which maintains information about the object boundary for use in robotic grasp planning. Our approach will be data-driven and generative, and we will base our probabilistic models on Kendall's Procrustean theory of shape.by Jared Marshall Glover.S.M

    Validating A Plasma Momentum Flux Sensor Against an Inverted Pendulum Thrust Stand

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76115/1/AIAA-2008-4739-514.pd

    Hall Thruster and VASIMR VX-100 Force measurements using a Plasma Momentum Flux Sensor

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76509/1/AIAA-2009-246-125.pd

    The VASIMR[registered trademark] VF-200-1 ISS Experiment as a Laboratory for Astrophysics

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    The VASIMR[R] Flight Experiment (VF-200-1) will be tested in space aboard the International Space Station (ISS) in about four years. It will consist of two 100 kW parallel plasma engines with opposite magnetic dipoles, resulting in a near zero-torque magnetic system. Electrical energy will come from ISS at low power level, be stored in batteries and used to fire the engine at 200 kW. The VF-200-1 project will provide a unique opportunity on the ISS National Laboratory for astrophysicists and space physicists to study the dynamic evolution of an expanding and reconnecting plasma loop. Here, we review the status of the project and discuss our current plans for computational modeling and in situ observation of a dynamic plasma loop on an experimental platform in low-Earth orbit. The VF-200-1 project is still in the early stages of development and we welcome new collaborators
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