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Real-time robot-assisted ergonomics

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arXiv 2018年

作者： Shafti, A. Ataka, A. Lazpita, B. Urbistondo Shiva, A. Wurdemann, H.A. Althoefer, K. Dept. of Computing Imperial College London Centre for Robotics Research King's College London. Department of Mechanical Engineering University College London Gower St. LondonWC1E 6BT United Kingdom School of Engineering and Materials Science Queen Mary University of London LondonE1 4NS United Kingdom

This paper describes a novel approach in human-robot interaction driven by ergonomics. With a clear focus on optimising ergonomics, the approach proposed here continuously observes a human user's posture and by invoking appropriate cooperative robot movements, the user's posture is, whenever required, brought back to an ergonomic optimum. Effectively, the new protocol optimises the human-robot relative position and orientation as a function of human ergonomics. An RGB-D camera is used to calculate and monitor human joint angles in real-time and to determine the current ergonomics state. A total of 6 main causes of low ergonomic states are identified, leading to 6 universal robot responses to allow the human to return to an optimal ergonomics state. The algorithmic framework identifies these 6 causes and controls the cooperating robot to always adapt the environment (e.g. change the pose of the workpiece) in a way that is ergonomically most comfortable for the interacting user. Hence, human-robot interaction is continuously re-evaluated optimizing ergonomics states. The approach is validated through an experimental study, based on established ergonomic methods and their adaptation for real-time application. The study confirms improved ergonomics using the new approach. Copyright © 2018, The Authors. All rights reserved.

关键词： Ergonomics

Comparison of Spinel and Monoclinic Crystal Structures of γ-Al2O3 for Simulation of Electron Energy Loss Spectra

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Microscopy and Microanalysis 2017年第S1期23卷 2020-2021页

作者： Henry O. Ayoola Cecile S. Bonifacio Qing Zhu Dong Su Joshua Kas John J. Rehr Eric A. Stach Wissam A. Saidi Judith C. Yang Dept. of Chemical and Petroleum Engineering University of Pittsburgh Pittsburgh PA (USA) Center for Functional Materials Brookhaven National Laboratory Upton NY (USA) Dept. of Physics University of Washington Seattle WA (USA) Dept. of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh PA (USA)

Complexity certification of a distributed augmented lagrangian method

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arXiv 2017年

作者： Lee, Soomin Chatzipanagiotis, Nikolaos Zavlanos, Michael M. Dept. of Industrial and Systems Engineering Georgia Tech AtlantaGA30318 United States Dept. of Mechanical Engineering and Materials Science Duke University DurhamNC27708 United States

In this paper we present complexity certification results for a distributed Augmented Lagrangian (AL) algorithm used to solve convex optimization problems involving globally coupled linear constraints. Our method relies on the Accelerated Distributed Augmented Lagrangian (ADAL) algorithm, which can handle the coupled linear constraints in a distributed manner based on local estimates of the AL. We show that the theoretical complexity of ADAL to reach an ϵ-optimal solution both in terms of suboptimality and infeasibility is O( 1 ϵ ) iterations. Moreover, we provide a valid upper bound for the optimal dual multiplier which enables us to explicitly specify these complexity *** also show how to choose the stepsize parameter to minimize the bounds on the convergence rates. Finally, we discuss a motivating example, a model predictive control (MPC) problem, involving a finite number of subsystems which interact with each other via a general network. Copyright © 2017, The Authors. All rights reserved.

关键词： Constrained optimization

Density Functional Theory-based modeling and calculations of a polyamide molecular unit for studying forward-osmosis-dewatering of microalgae

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Density Functional Theory-based modeling and calculations of...

IEEE International Conference on Humanoid, Nanotechnology, Information Technology, Communication and Control, Environment and Management

作者： Jester N. Itliong Al Rey C. Villagracia Joaquin Lorenzo V. Moreno Gian Paolo O. Bernardo Kurt Irvin M. Rojas Melanie Y. David Robby B. Manrique Allan Abraham B. Padama Aristotle T. Ubando Alvin B. Culaba Jo-Shu Chang Nelson B. Arboleda Wei-Hsin Chen Hui Lin Ong Hideaki Kasai Physics Department De La Salle University and Applied Physics Department Eulogio “Amang” Rodriguez Institute of Science and Technology Manila Philippines Physics Department De La Salle University Manila Philippines Mechanical Engineering Dept. De La Salle University Manila Philippines Institute of Math. Sci. & Physics University University of the Philippines Los Baños Laguna Philippines Dept. of Chemical Engineering National Cheng Kung University Tainan Taiwan Dept. of Aeronautics & Astronautics National Cheng Kung University Tainan Taiwan School of Materials Engineering Universiti Malaysia Perlis Perlis Malaysia Akashi College National Institute of Technolgy Hyogo Japan

Both the preparation of a reliable all-atom model of a polyamide (PA) membrane and the determination of its electrostatic parameters are considered significant challenges in a proposal to study forward-osmosis-dewatering of microalgae using molecular dynamics (MD). Density functional theory (DFT)-based calculations can effectively calculate for optimized structure and electrostatic properties, thus, employed to model and characterize the PA membrane starting from its molecular unit. The performed structural optimization resulted to the most stable configuration of the PA unit with bond length values that showed strong stability in the molecule such as the amide bond length of 1.413 A which was found to differ from that of a related study by ～3%. The calculated charge density distributions, electrostatic potential isosurface, and Mulliken charges on the PA unit provided potential binding sites and insights on the formation of amide bonds on the PA molecule. The non-amide-bonded nitrogen atom of m-phenylene diamine (MPD) was found to be the most active site in the molecule due to its highest magnitude of negative charge (positive Coulomb potential), suggesting that amide bond-formation with a carbon atom of a trimesoyl chloride (TMC) monomer is most likely to occur during polymerization. The calculated charges in the amide group and the zero-net sum of these charges also agreed reasonably well with another study. The results are of vital importance in parameterizing the interaction potentials of PA for use in the MD simulations.

关键词： Electric potential Electrostatics Optimization Physics Isosurfaces Polymers Biomembranes

Rapid Nanometer Mapping of Nickel-Steel Friction Stir Weld Joint

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Microscopy and Microanalysis 2017年第S1期23卷 578-579页

作者： Genevieve Lee Guilherme Abreu-Faria F Johnnatan Rodríguez Jonathan Orsborn Antonio J. Ramirez Welding Eng. Program Dept. of Materials Science and Eng. The Ohio State University - Columbus OH USA Center for Design and Manufacturing Excellence College of Engineering The Ohio State University -Columbus OH USA. Manufacturing and Materials Joining Innovation Center - Ma2JIC Dept. of Materials Science and Eng. The Ohio State University - Columbus OH USA Dept. of Mechanical Engineering EIA University - Envigado Ant. Colombia Center for Electron Microscopy Dept. of Materials Science and Eng. The Ohio State University -Columbus OH USA Center for the Accelerated Maturation of Materials Dept. of Materials Science and Eng. The Ohio State University Columbus OH

Numerical study of fuselage aerodynamics of DLR-F6 wing-body in ground effect 35

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Numerical study of fuselage aerodynamics of DLR-F6 wing-body...

35th AIAA Applied Aerodynamics Conference, 2017

作者： Deng, Ning Qu, Qiulin Agarwal, Ramesh K. Dept. of Mechanical Engineering and Materials Science Washington University in St. Louis St. LouisMO63130 United States Institute of Fluid Mechanics Beijing University of Aeronautics and Astronautics Washington University in St. Louis St. LouisMO63130 United States

ISBN: (数字)9781624105012

ISBN: (纸本)9781624105012

The main focus of this paper is on the simulation of flow past a three-dimensional wing-body configuration (DLR-F6) in ground effect. For the purpose of validation of the simulation approach, computations are performed for the DLR-F6 wing-body in unbounded flow and are compared with the experimental data. The commercial CFD solver ANSYS FLUENT is employed for computations. Compressible Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with Spalart-Allmaras (SA) and K-ω Shear Stress Transport (SST) turbulence models are solved. The validated code is employed to calculate the flow field in ground effect. In particular, the aerodynamics of the fuselage is analyzed in detail. The effects of flight heights above the ground on the aerodynamic properties and flow field are analyzed. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Ground effect

Physical, mechanical and thermal properties of lightweight foamed concrete with fly ash

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IOP Conference Series: materials science and engineering 2018年第1期420卷

作者： Chundakus Habsya Kuncoro Diharjo Prabang Setyono Prasasto Satwiko Doctor Candidate in Postgraduate Program Sebelas Maret University Indonesia Mechanical Engineering Dept. Engineering Faculty Sebelas Maret University Surakarta Indonesia Environmental Science Dept. Postgraduate Program Sebelas Maret University Surakarta Indonesia Department of Architecture Faculty of Engineering Universitas Atma Jaya Yogyakarta Indonesia

This study aims to investigate the effect of fly ash content on the density, thermal conductivity, compressive strength and water absorption of Lightweight Foamed Concrete (LFC). This LFC consists of cement, water, sand, fly ash (FA) and foam. The foam is needed to to create air voids in the mixture and reduce its weight. The foaming agent which was diluted in the water was given air pressure using foam generator to produce foam. The LFC are made with water-cement ratio of 1:1 and cement-agregat ratio of 1: 4. Aggregates consisted of sand and FA varied by 0%, 10%, 20% and 30% in weight. The content offoam was 30% and 40% of the mortar volume. The increasing of foam content decreases density, thermal conductivity, and compressive strength of LFC. However, that increases its water absorption. The increasing of FA contentalso decreases water absorption, but it density, thermal conductivity and compressive strength.

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Thermal marangoni-driven dynamics of spinning liquid films

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arXiv 2018年

作者： Dijksman, Joshua A. Mukhopadhyay, Shomeek Behringer, Robert P. Witelski, Thomas P. Physical Chemistry and Soft Matter Wageningen University & Research Wageningen Netherlands Department of Mechanical Engineering and Materials Science Yale University New HavenCT06511 United States Dept. of Physics & Center for Nonlinear and Complex Systems Duke University Box 90305 DurhamNC27708-0305 United States Department of Mathematics Duke University Box 90320 DurhamNC27708-0320 United States

Spin coating of thin films of viscous liquids on a rotating substrate is a core technological component of semiconductor microchip fabrication. The thinning dynamics is influenced by many physical processes. Specifically temperature gradients affect thin liquid films through their influence on the local fluid surface tension. We show here experimentally and numerically that adding a static temperature gradient has a significant effect on the equilibrium film thickness and height profile reached in spin coating. Our results suggest that thermal gradients can be used to control film height profile dynamics. Copyright © 2018, The Authors. All rights reserved.

关键词： Thin films

Controlling a robotic stereo camera under image quantization noise

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arXiv 2017年

作者： Freundlich, Charles Zhang, Yan Zhu, Alex Zihao Mordohai, Philippos Zavlanos, Michael M. Dept. of Mechanical Engineering and Materials Science Duke University DurhamNC27708 United States Dept. of Computer Science Stevens Institute of Technology HobokenNJ07030 United States Dept. of Computer and Information Science University of Pennsylvania PhiladelphiaPA United States

In this paper, we address the problem of controlling a mobile stereo camera under image quantization noise. Assuming that a pair of images of a set of targets is available, the camera moves through a sequence of Next-Best-Views (NBVs), i.e., a sequence of views that minimize the trace of the targets' cumulative state covariance, constructed using a realistic model of the stereo rig that captures image quantization noise and a Kalman Filter (KF) that fuses the observation history with new information. The proposed algorithm decomposes control into two stages: first the NBV is computed in the camera relative coordinates, and then the camera moves to realize this view in the fixed global coordinate frame. This decomposition allows the camera to drive to a new pose that effectively realizes the NBV in camera coordinates while satisfying Field-of-View constraints in global coordinates, a task that is particularly challenging using complex sensing models. We provide simulations and real experiments that illustrate the ability of the proposed mobile camera system to accurately localize sets of targets. We also propose a novel data-driven technique to characterize unmodeled uncertainty, such as calibration errors, at the pixel level and show that this method ensures stability of the KF. Copyright © 2017, The Authors. All rights reserved.

关键词： Cameras