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Nonlinear control for a Model-scaled Helicopter with Constraints on Rotor Thrust and Fuselage Attitude

自动化学报 2014年第11期40卷 2654-2664页

作者： ZHU Bing The Seventh Research Division Beihang University Beijing 100191 China Department of Electrical Electronic and Computer Engineering University of Pretoria Pretoria 0083 South Africa Science and Technology on Aircraft Control Laboratory Beihang University Beijing 100191 China

A nonlinear control is proposed for trajectory tracking of a 6-DOF model-scaled helicopter with constraints on main rotor thrust and fuselage attitude. In the procedure of control design, the mathematical model of helicopter is simplified into three subsystems: altitude subsystem, longitudinal-lateral subsystem and attitude subsystem. The proposed control is developed by combining the sub-controls for the corresponding subsystems. The sub-controls for altitude subsystem and longitudinal-lateral subsystem are designed with hyperbolic tangent functions to satisfy the constraints; the sub-control for attitude subsystem is based on backstepping technique such that fuselage attitude tracks the virtual control for longitudinal-lateral subsystem. It is proved theoretically that tracking errors are ultimately bounded, and control constraints are satisfied. Performances of the proposed controller are demonstrated by simulation results.

关键词：直升机旋翼控制模型非线性控制机身姿态推力缩放双曲正切函数

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Materials Science/Clinical Medi Cine: Epidermal devices for noninvasive, precise, and continuous mapping of macrovascular and microvascular blood flow

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Science Advances 2015年第9期1卷

作者： Webb, R. Chad Ma, Yinji Krishnan, Siddharth Li, Yuhang Yoon, Stephen Guo, Xiaogang Feng, Xue Shi, Yan Seidel, Miles Cho, Nam Heon Kurniawan, Jonas Ahad, James Sheth, Niral Kim, Joseph TaylorVI, James G. Darlington, Tom Chang, Ken Huang, Weizhong Ayers, Joshua Gruebele, Alexander Pielak, Rafal M. Slepian, Marvin J. Huang, Yonggang Gorbach, Alexander M. Rogers, John A. Department of Materials Science and Engineering Frederick Seitz Materials Research Laboratory University of Illinois at Urbana-Champaign UrbanaIL61801 United States Departments of Civil and Environmental Engineering Mechanical Engineering Center for Engineering and Health Skin Disease Research Center Northwestern University EvanstonIL60208 United States Department of Engineering Mechanics Center for Mechanics and Materials Tsinghua University Beijing100084 China Institute of Solid Mechanics Beihang University Beijing100191 China National Institute of Biomedical Imaging and Bioengineering National Institutes of Health BethesdaMD20892 United States College of Aerospace and Civil Engineering Harbin Engineering University Harbin150001 China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing210016 China Genomic Medicine Section Hematology Branch National Heart Lung and Blood Institute National Institutes of Health BethesdaMD20892 United States Department of Electrical and Computer Engineering Frederick Seitz Materials Research Laboratory University of Illinois at Urbana-Champaign UrbanaIL61801 United States L'Oreál California Research Center 953 Indiana Street San FranciscoCA94107 United States Department of Medicine Sarver Heart Center Department of Biomedical Engineering University of Arizona TucsonAZ85724 United States

Continuous monitoring of variations in blood flow is vital in assessing the status of microvascular and macrovascular beds for a wide range of clinical and research scenarios. Although a variety of techniques exist, most require complete immobilization of the subject, thereby limiting their utility to hospital or clinical settings. Those that can be rendered in wearable formats suffer from limited accuracy, motion artifacts, and other shortcomings that follow from an inability to achieve intimate, noninvasive mechanical linkage of sensors with the surface of the skin. We introduce an ultrathin, soft, skin-conforming sensor technology that offers advanced capabilities in continuous and precise blood flow mapping. Systematic work establishes a set of experimental procedures and theoretical models for quantitative measurements and guidelines in design and operation. Experimental studies on human subjects, including validation with measurements performed using state-of-the-art clinical techniques, demonstrate sensitive and accurate assessment of both macrovascular and microvascular flow under a range of physiological conditions. Refined operational modes eliminate long-term drifts and reduce power consumption, thereby providing steps toward the use of this technology for continuous monitoring during daily activities. © 2015 The Authors, some rights reserved.

关键词： Blood

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Low Complexity Constraint control Using Contractive Sets

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IFAC Proceedings Volumes 2014年第3期47卷 2933-2938页

作者： Morten Hovd Sorin Olaru George Bitsoris Engineering Cybernetics Department Norwegian University of Science and Technology N-7491 Trondheim Norway SUPELEC Systems Science Automatic Control Department and EPIINRIA DISCO 3 rue Joliot Curie 91192 France Control Systems Laboratiry Department of Electrical and Computer Engineering University of Patras 26500 Patras Greece

This paper proposes a simple, non-iterative way of calculating low-complexity controlled contractive sets, and shows how such set can be used for controller design for systems with state and input constraints. The result is a low complexity controller, suitable for implementation in embedded control systems with modest computational power and available memory.

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Fluid dynamic characterization of a novel branching anastomosis design

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International Biomechanics 2015年第1期2卷 73-78页

作者： Samuelson, Rodney Nair, Priya Snyder, Kenneth Frakes, David Preul, Mark C. Nakaji, Peter Spetzler, Robert F. Division of Neurological Surgery Barrow Neurological Institute Phoenix AZ United States School of Biological and Health Systems Engineering Arizona State University Tempe AZ United States Department of Neurosurgery University of Buffalo Buffalo NY United States School of Electrical Computer and Energy Engineering Arizona State University Tempe AZ United States Neurosurgery Research Laboratory Barrow Neurological Institute Phoenix AZ United States

Geometric characteristics of a vascular anastomosis can have important biomechanical impacts, particularly in the hemodynamic context of wall shear stress (WSS). In this study, we propose a new branching anastomosis design, the Hybrid anastomosis, to connect a donor vessel to two recipient vessels. The central obstruction characteristic of the traditional Figure 8 anastomosis is mitigated by creating a recessed lumen at the bifurcation. Chicken vessels were used to create and test three Figure 8 and three Hybrid anastomoses ex vivo. Computational fluid dynamics (CFD) simulations of idealized anastomosis designs were then used to verify the experiments and further studied the WSS and WSS gradient (WSSG) profiles of the designs. Experimental results showed increased flow through the Hybrid anastomosis (0.40 ml/s vs. 0.23 ml/s). The mean suture time averaged 20 and 28 min for the Figure 8 and Hybrid anastomoses, respectively. CFD simulations agreed with the experiments;the simulations showed lower flow resistance in the Hybrid anastomosis (1.89 kPa-s/ml vs. 6.77 kPa-s/ml). Most importantly, a set of more physiologically realistic simulations showed that the Hybrid anastomosis reduced WSS and WSSG by over 60% as compared to the Figure 8. Results demonstrated that the proposed Hybrid anastomosis can be created on a comparable surgical time scale (and from the same initial vasculature) as compared to the Figure 8 anastomosis, while decreasing flow resistance and reducing WSS and WSSG considerably. These findings support that the new Hybrid anastomosis may represent a favorable surgical alternative to the Figure 8 design. © 2015 The Author(s). Published by Taylor & Francis.

关键词： Anastomosis Computational fluid dynamics Wall shear stress

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Conformational Dynamics of apo‐GlnBP Revealed by Experimental and Computational Analysis

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Angewandte Chemie 2016年第45期128卷

作者： Yitao Feng Lu Zhang Shaowen Wu Zhijun Liu Xin Gao Xu Zhang Maili Liu Jianwei Liu Xuhui Huang Wenning Wang Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Department of Chemistry and Institutes of Biomedical Sciences Fudan University Shanghai P.R. China Department of Chemistry The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong National Center for Protein Science Shanghai Institute of Biochemistry and Cell Biology Chinese Academy of Sciences Shanghai China King Abdullah University of Science and Technology (KAUST) Computational Bioscience Research Center (CBRC) Computer Electrical and Mathematical Sciences and Engineering (CEMSE) Division Thuwal 23955 Saudi Arabia Key Laboratory of Magnetic and Resonance in Biological Systems State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Centre for Magnetic Resonance Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan China Division of Biomedical Engineering Center of Systems Biology and Human Health Institute for Advance Study and School of Science The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong

The glutamine binding protein (GlnBP) binds l ‐glutamine and cooperates with its cognate transporters during glutamine uptake. Crystal structure analysis has revealed an open and a closed conformation for apo‐ and holo‐GlnBP, respectively. However, the detailed conformational dynamics have remained unclear. Herein, we combined NMR spectroscopy, MD simulations, and single‐molecule FRET techniques to decipher the conformational dynamics of apo‐GlnBP. The NMR residual dipolar couplings of apo‐GlnBP were in good agreement with a MD‐derived structure ensemble consisting of four metastable states. The open and closed conformations are the two major states. This four‐state model was further validated by smFRET experiments and suggests the conformational selection mechanism in ligand recognition of GlnBP.

关键词： FRET Konformationsdynamik Moleküldynamik NMR-Spektroskopie Proteinfaltung

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Calibrationless parallel imaging reconstruction based on structured low-rank matrix completion

Calibrationless parallel imaging reconstruction based on str...

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作者： Shin, Peter J. Larson, Peder E. Z. Ohliger, Michael A. Elad, Michael Pauly, John M. Vigneron, Daniel B. Lustig, Michael Department of Radiology and Biomedical Imaging University of California at San Francisco San FranciscoCA United States UC Berkeley-UCSF Graduate Program in Bioengineering CA United States Department of Electrical Engineering and Computer Science University of California at Berkeley BerkeleyCA United States Department of Computer Science Technion'Israel Institute of Technology Haifa Israel Magnetic Resonance Systems Research Laboratory Department of Electrical Engineering Stanford University StanfordCA United States

Purpose: A calibrationless parallel imaging reconstruction method, termed simultaneous autocalibrating and k-space estimation (SAKE), is presented. It is a data-driven, coil-by-coil reconstruction method that does not require a separate calibration step for estimating coil sensitivity information. Methods: In SAKE, an undersampled, multichannel dataset is structured into a single data matrix. The reconstruction is then formulated as a structured low-rank matrix completion problem. An iterative solution that implements a projection-ontosets algorithm with singular value thresholding is described. Results: Reconstruction results are demonstrated for retrospectively and prospectively undersampled, multichannel Cartesian data having no calibration signals. Additionally, non-Cartesian data reconstruction is presented. Finally, improved image quality is demonstrated by combining SAKE with wavelet-based compressed sensing. Conclusion: Because estimation of coil sensitivity information is not needed, the proposed method could potentially benefit MR applications where acquiring accurate calibration data is limiting or not possible at all. © 2013 Wiley Periodicals, Inc.

关键词： Compressed sensing

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Acquiring brain signals of imagining humanoid robot walking behavior via cerebot

Advances in Intelligent Systems and Computing

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Advances in Intelligent systems and Computing 2014年 215卷 617-627页

作者： Li, Wei Li, Yunyi Chen, Genshe Meng, Qinghao Zeng, Ming Sun, Fuchun Tianjin University Tianjin China Department of Computer and Electrical Engineering and Computer Science California State University Bakersfield 9001 Stockdale Hwy Bakersfield CA 93311-1022 United States Department of Psychology and Neuroscience Duke University 417 Chapel Drive Durham NC 27708-0086 United States I-Fusion Technologies Inc Germantown MD 20874 United States State Key Laboratory of Intelligent Technology and Systems Tsinghua University Beijing China

control of humanoid robot behavior with the mind begins a new era of robotics research. One of the critical issues in this research is how to acquire the brain signals with high quality which are correlated to humanoid robot behavior. In order to improve subjects' concentration on their mental activities during tests, we develop a stimuli module in the Cerebot system, consisting of a Cerebus neural data acquisition system and a Kumotek robot with 20 degrees of freedom or a NAO robot with 25 degrees of freedom. We present the experimental procedures for acquiring brain signals of imagining humanoid robot walking behavior by using movies of robot walking or real robot walking activities. We record two groups of brain signals correlated to mental activities of six robot walking behavior. Finally, we present a demonstration of controlling the humanoid robot walking behavior using the phase coding mechanisms of the Delta rhythms. © Springer-Verlag Berlin Heidelberg 2014.

关键词： Anthropomorphic robots

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Improved perturbation bounds for the continuous-time H∞-control problem

Improved perturbation bounds for the continuous-time H∞-con...

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作者： Christov, Nicolai D. Konstantinov, Mihail M. Petkov, Petko Hr. Laboratory of Automatics Computer Engineering and Signal Processing Lille University of Science and Technology Villeneuve d'Ascq59655 France Department of Mathematics University of Architecture Civil Engineering and Geodesy Sofia1046 Bulgaria Department of Systems and Control Technical University of Sofia Sofia1000 Bulgaria

New local perturbation bounds for the continuous-time H∞-control problem are obtained, which are nonlinear functions of the data perturbations and are tighter than the existing condition number-based local bounds. These nonlinear local bounds are then incorporated into nonlocal perturbation bounds which are less conservative than the existing nonlocal perturbation estimates for the H∞-control problem. Copyright © 2014, Kent State University.

关键词： Riccati equations

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Program-based and model-based PLC design environment for multicore FPGA architectures 11

Program-based and model-based PLC design environment for mul...

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11th International Conference on Informatics in control, Automation and Robotics, ICINCO 2014

作者： Economakos, Christoforos Skarpetis, Michael Economakos, George Technological Educational Institution of Sterea Ellada Department of Automation Engineering Psahna EviaGR34400 Greece National Technical University of Athens School of Electrical and Computer Engineering Microprocessors and Digital Systems Laboratory Heroon Polytechniou 9 Zografou AthensGR15780 Greece

ISBN: (纸本)9789897580390

Digital design has been growing rapidly during the last years, offering advanced implementation solutions for a diversity of appliances and instruments, integrating different sensors and actuators. This has a great impact on embedded automation, where traditional Programmable Logic controllers (PLCs) have been gradually replaced by high performance Embedded controllers, Digital Signal Processor (DSP) chips and, more recently, power efficient Field Programmable Gate Arrays (FPGAs). Such new implementation platforms bring together efficient design methodologies, like model-based design and high-level or C level program-based design. In their turn, new design methodologies are accompanied by new design technologies like Intellectual Property (IP) based design and High-Level Synthesis (HLS). This paper presents a design environment that utilizes program-based and model-based design, for the development of PLC applications. Specifically, a tool flow is constructed that supports either the design of new control algorithms or the translation of existing algorithms into C. Then, HLS and FPGA implementation tools are adopted, to implement the selected algorithms as mul-ticore, embedded designs, offering performance improvements and hardware utilization efficiency. Overall, the proposed methodology and underlying tool flow support a novel high productivity prototyping platform for digital control applications, with very promising future extension capabilities.

关键词： Programmable logic controllers

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On the Cooperative Observability of a Continuous-Time Linear System on an Undirected Network

On the Cooperative Observability of a Continuous-Time Linear...

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International Joint Conference on Neural Networks

作者： Henghui Zhu Kexin Liu Jinhu Lu Zongli Lin Yao Chen Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Chinese Academy of Sciences Charles L. Brown Department of Electrical and Computer Engineering University of Virginia School of Electronic and Information Engineering Beijing Jiaotong University

ISBN: (纸本)9781479914821

In traditional control theory, a single observer has access all the measured outputs of the plant to estimates its asymptotically. In many real world engineering systems, it may be difficult to build a single observer that has access to all the measured outputs. One way around this difficulty is to build a network of cooperative observers, each of which obtains a portion of the measurement outputs, that collectively produce an asymptotic estimate of the plant state. In this paper, we construct a network of such observers for a continuous-time linear system. Assuming that these observers are connected through an undirected connected network, we establish a necessary and sufficient condition on the plant parameters under which the network of observers will achieve asymptotic omniscience. A network of cooperative observers is said to achieve asymptotic omniscience if their states all converge to the plant state asymptotically. Numerical simulation results are presented to validate theoretical results. The design of cooperative observers sheds some light on the solution of some other real-world problems, such as the design of networked location-based services and sensor networks.

关键词： Observers Eigenvalues and eigenfunctions Laplace equations Couplings Symmetric matrices Linear systems Kalman filters

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