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LANDING AN UNMANNED AIR VEHICLE: VISION BASED MOTION ESTIMATION AND NONLINEAR CONTROL

Asian Journal of Control 2008年第3期1卷

作者： Omid Shakernia Yi Ma T. John Koo Shankar Sastry Dept. of Electrical Engineering & Computer Science University of California at Berkeley Berkeley CA94720-1774 U.S.A. Tak-Kuen John Koo received the B.Eng. degree in 1992 in Electronic Engineering and the M.Phil. in 1994 in Information Engineering both from the Chinese University of Hong Kong. From 1994 to 1995 he was a graduate student in Signal and Image Processing Institute at the University of Southern California. He is currently a Ph.D. Candidate in Electrical Engineering and Computer Sciences at the University of California at Berkeley. His research interests include nonlinear control theory hybrid systems inertial navigation systems with applications to unmanned aerial vehicles. He received the Distinguished M.Phil. Thesis Award of the Faculty of Engineering The Chinese University of Hong Kong in 1994. He was a consultant of SRI International in 1998. Currently he is the team leader of the Berkeley AeRobot Team and a delegate of The Graduate Assembly University of California at Berkeley. He is a student member of IEEE and SIAM. S. Shankar Sastry received his Ph.D. degree in 1981 from the University of California Berkeley. He was on the faculty of MIT from 1980-82 and Harvard University as a Gordon McKay professor in 1994. He is currently a Professor of Electrical Engineering and Computer Sciences and Bioengineering and Director of the Electronics Research Laboratory at Berkeley. He has held visiting appointments at the Australian National University Canberra the University of Rome Scuola Normale and University of Pisa the CNRS laboratory LAAS in Toulouse (poste rouge) and as a Vinton Hayes Visiting fellow at the Center for Intelligent Control Systems at MIT. His areas of research are nonlinear and adaptive control robotic telesurgery control of hybrid systems and biological motor control. He is a coauthor (with M. Bodson) of “Adaptive Control: Stability Convergence and Robustness Prentice Hall 1989.” and (with R. Murray and Z. Li) of “A Mathematical Introduction to Robotic Manipulati

In this paper, we use computer vision as a feedback sensor in a control loop for landing an unmanned air vehicle (UAV) on a landing pad. The vision problem we address here is then a special case of the classic ego-motion estimation problem since all feature points lie on a planar surface (the landing pad). We study together the discrete and differential versions of the ego-motion estimation, in order to obtain both position and velocity of the UAV relative to the landing pad. After briefly reviewing existing algorithm for the discrete case, we present, in a unified geometric framework, a new estimation scheme for solving the differential case. We further show how the obtained algorithms enable the vision sensor to be placed in the feedback loop as a state observer for landing control. These algorithms are linear, numerically robust, and computationally inexpensive hence suitable for real-time implementation. We present a thorough performance evaluation of the motion estimation algorithms under varying levels of image measurement noise, altitudes of the camera above the landing pad, and different camera motions relative to the landing pad. A landing controller is then designed for a full dynamic model of the UAV. Using geometric nonlinear control theory, the dynamics of the UAV are decoupled into an inner system and outer system. The proposed control scheme is then based on the differential flatness of the outer system. For the overall closed-loop system, conditions are provided under which exponential stability can be guaranteed. In the closed-loop system, the controller is tightly coupled with the vision based state estimation and the only auxiliary sensor are accelerometers for measuring acceleration of the UAV. Finally, we show through simulation results that the designed vision-in-the-loop controller generates stable landing maneuvers even for large levels of image measurement noise. Experiments on a real UAV will be presented in future work.

关键词： Motion estimation computer vision based control unmanned air vehicle differential flatness

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A machine learning approach to determine semantic dependency structure in Chinese

A machine learning approach to determine semantic dependency...

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FLAIRS 2006 - 19th International Florida Artificial Intelligence Research Society Conference

作者： Yan, Jiajun Bracewell, David B. Ren, Fuji Kuroiwa, Shingo Department of Information Science and Intelligent Systems Faculty of Engineering University of Tokushima Tokushima 770-8506 Japan

In this paper, we attempt to automatically annotate the Penn Chinese Treebank with semantic dependency structure. Initially a small portion of the Penn Chinese Treebank was manually annotated with headword and semantic dependency relations. An initial investigation is then done using a Naive Bayesian Classifier and some handcrafted rules. The results show that the algorithms and proposed approach are effective at determining semantic dependency structure automatically. The Naive Bayesian Classifier makes a good baseline algorithm for future research.

关键词： Learning systems

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Robust multi-target tracking using spatio-temporal context

Robust multi-target tracking using spatio-temporal context

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2006 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, CVPR 2006

作者： Nguyen, Hieu T. Qiang, Ji Smeulders, Arnold W. M. Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute United States Intelligent Sensory Information Systems Faculty of Science University of Amsterdam Netherlands

ISBN: (纸本)0769525970

In multi-target tracking, the maintaining of the correct identity of targets is challenging. In the presented tracking method, accurate target identification is achieved by incorporating the appearance information of the spatial and temporal context of each target. The spatial context of a target involves local background and nearby targets. The first contribution of the paper is to provide a new discriminative model for multi-target tracking with the embedded classification of each target against its context. As a result, the tracker not only searches for the image region similar to the target but also avoids latching on nearby targets or on a background region. The temporal context of a target includes its appearances seen during tracking in the past. The past appearances are used to train a probabilistic PCA that is used as the measurement model of the target at the present. As the second contribution, we develop a new incremental scheme for probabilistic PCA. It can update accurately the full set of parameters including a noise parameterstill ignored in related literature. The experiments show robust tracking performance under the condition of severe clutter, occlusions and pose changes. © 2006 IEEE.

关键词： Automatic target recognition

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Cover Picture: Single DNA Molecule Isolation and Trapping in a Microfluidic Device (ChemPhysChem 12/2007)

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ChemPhysChem 2007年第12期8卷 1733-1733页

作者： Momoko Kumemura Dr. Dominique Collard Prof. Dr. Christophe Yamahata Dr. Naoyoshi Sakaki Dr. Gen Hashiguchi Prof. Dr. Hiroyuki Fujita Prof. Dr. Center for International Research on MicroMechatronics Institute of Industrial Science The University of Tokyo 4-6-1 Komaba Meguro-ku Tokyo 153-8505 Japan Fax: (+81) 3-5452-6250 Laboratory for Integrated Micro Mechatronic Systems LIMMS/CNRS-IIS Institute of Industrial Science The University of Tokyo 4-6-1 Komaba Meguro-ku Tokyo 153-8505 Japan Department of Intelligent Mechanical Systems Engineering Faculty of Engineering Kagawa University 2217-20 Hayashi-cho Takamatsu 761-0396 Japan

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Emotion estimation system based on emotion occurrence sentence pattern

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International Conference on intelligent Computing, ICIC 2006

作者： Matsumoto, Kazuyuki Fuji, Ren Kuroiwa, Shingo Department of Information Science and Intelligent Systems Faculty of Engineering University of Tokushima Minami-Josanjima-Cho Tokushima-shi 770-8506 Japan School of Information Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

ISBN: (纸本)3540372741

The approach of emotion estimation from the conventional text was for estimating superficial emotion expression mainly. However emotions may be included in human's utterance even if emotion expressions are not in it. In this paper, we proposed an emotion estimation algorithm for conversation sentence. We gave the rules of emotion occurrence to 1616 sentence patterns. In addition, we developed a dictionary which consisted of emotional words and emotional idioms. The proposed method can estimate emotions in a sentence by matching the sentence pattern of emotion occurrence and the rule. Furthermore, we can get two or more emotions included in the sentence by calculating emotion parameter. We constructed the experiment system based on the proposed method for evaluation. We analyzed weblog data including 253 sentences by the system, and conducted the experiment to evaluate emotion estimation accuracy. As a result, we obtained the estimation accuracy of about 60 %. © Springer-Verlag Berlin Heidelberg 2006.

关键词： Pattern recognition systems

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Double-array compression by pruning twin leaves and unifying common suffixes

Double-array compression by pruning twin leaves and unifying...

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International Conference on Computing & Informatics (ICOCI)

作者： Susumu Yata Masaki Oono Kazuhiro Morita Toru Sumitomo Jun-ichi Aoe Department of Information Science and Intelligent Systems Faculty of Engineering University of Tokushima Japan

A minimal prefix (MP) trie is a tree structure for key retrieval, and a double-array is an efficient data structure for the MP trie. This paper presents two compression methods for the double-array. One method removes leaf nodes following two-way arcs (named twin leaves) from the MP trie. The other method unifies common suffixes. Experimental results show that space usage of the double-array is reduced to about 60% by the two methods.

关键词： Tail Information retrieval Information science intelligent systems intelligent structures data engineering systems engineering and theory data structures Tree data structures Natural languages

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Sintering behavior and mechanical properties of injection molded Ti-4.3Fe-7.1Cr alloys

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Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 2006年第10期53卷 821-826页

作者： Itoh, Yoshinori Uematsu, Toshiaki Sato, Kenji Miura, Hideshi Niinomi, Mitsuo Ikeda, Masahiko Hamamatsu Industrial Research Institute of Shizuoka Prefecture 1-3-3 Shinmiyakoda Hamamatsu 431-2103 Japan Department of Intelligent Machinery and Systems Faculty of Engineering Kyusyu University 744 Motooka Nishi-ku Fukuoka 819-0395 Japan Department of Biomaterials Science Institute for Materials Research Tohoku University 2-1-1 Katahira Aoba-ku Sendai 980-8577 Japan Department of Materials Science and Engineering Faculty of Engineering Kansai University 3-3-35 Yamate-cho Suita 564-8680 Japan

The metal injection molding process was used to produce the Ti-4.3Fe-7.1Cr alloy compacts using the mixture of Ti and Fe-Cr alloy powders, and mixed elemental powder. The effect of mixed powder and sintering temperature on the densification behavior, mechanical properties and microstructures of the compacts were mainly investigated. The compacts sintered at below 1423 K using a mixed elemental powder showed higher density and tensile strength as compared to the compacts using a mixture of Ti and Fe-Cr alloy powders. However, the tensile elongation at fracture of sintered compacts using both mixed powders was about 3%. Characteristic X-ray images and X-ray diffraction measurement confirms a particle dispersion, which is thought to be precipitation of αTi phase, along the grain boundaries. Eventually, the tensile strength and relative density of the compacts sintered at 1423 K using a mixed elemental powder attain 1160 MPa and 96.9%, respectively.

关键词： Titanium alloys

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Theory of Internet Auctions

Theory of Internet Auctions

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IEEE International Conference on systems, Man and Cybernetics

作者： Makoto Yokoo Department of Intelligent Systems Faculty of Information Science and Electrical Engineering Kyushu University Fukuoka Japan

Electronic commerce (EC) is a promising field for applying agent and artificial intelligence technologies. This article shows an overview of the theory of Internet auctions. First, we explain the basic terms and concepts used in auction and game theory literature. Then, we describe various auction protocols and examine the theoretical characteristics of these protocols.

关键词： Internet Protocols Electronic commerce Artificial intelligence Telephony Costs Cybernetics Game theory Robustness Microeconomics

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Obituary

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European Journal of Control 2006年第3期12卷 346-348页

作者： Ron Patton Steven Ding Control & Intelligent Systems Engineering Research group Department of Engineering Faculty of Applied Science & Technology The University of Hull UK Institute for Automatic Control and Complex Systems (AKS) Faculty of Engineering University of Duisburg-Essen Germany

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Robust multi-target tracking using spatio-temporal context

Robust multi-target tracking using spatio-temporal context

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Conference on Computer Vision and Pattern Recognition (CVPR)

作者： H.T. Nguyen Qiang Ji A.W.M. Smeulders Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute USA Intelligent Sensory Information Systems Faculty of Science University of Amsterdam Netherlands

In multi-target tracking, the maintaining of the correct identity of targets is challenging. In the presented tracking method, accurate target identification is achieved by incorporating the appearance information of the spatial and temporal context of each target. The spatial context of a target involves local background and nearby targets. The first contribution of the paper is to provide a new discriminative model for multi-target tracking with the embedded classification of each target against its context. As a result, the tracker not only searches for the image region similar to the target but also avoids latching on nearby targets or on a background region. The temporal context of a target includes its appearances seen during tracking in the past. The past appearances are used to train a probabilistic PCA that is used as the measurement model of the target at the present. As the second contribution, we develop a new incremental scheme for probabilistic PCA. It can update accurately the full set of parameters including a noise parameter still ignored in related literature. The experiments show robust tracking performance under the condition of severe clutter, occlusions and pose changes.

关键词： Target tracking Principal component analysis Maintenance engineering systems engineering and theory intelligent systems intelligent sensors Information systems Context modeling Noise robustness Layout

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