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Robust Adaptive Fault-Tolerant Control of the F-14 Aircraft under Sensor Failures

IFAC Proceedings Volumes 2008年第2期41卷 10172-10177页

作者： Sajjad Fekri Dawei Gu Ian Postlethwaite Michael Athans Control & Instrumentation Research Group Department of Engineering University of Leicester U.K. (Tel: +44-116-2522567 Fax: +44-116-2522619 Institute for Systems and Robotics (ISR) Instituto Superior Técnico (IST) Lisbon Portugal also Professor of EE&CS (emeritus) MIT Cambridge MA U.S.A.

This paper presents a novel fault detection and isolation (FDI) architecture applied to the lateral-directional axis of an F-14 aircraft during powered approach to landing under sensor failures. The fault-tolerant architecture employed is based on the so-called “Robust Multiple-Model Adaptive Control” (RMMAC) and hence is referred to as “RMMAC/FDI”. The results demonstrate successful stability and performance of the RMMAC/FDI architecture.

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Switched Thermal Anemometer

Switched Thermal Anemometer

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2008 IEEE Instrumentation and Measurement Technology Conference (I2MTC 2008), vol.5

作者： Lino Marques Grzegorz Tomaszewski Anibal T. de Almeida Institute for Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Coimbra Portugal

A new experimental circuit arrangement for a thermal anemometer using a microcontroller as a control unit is described. The device uses a boost-configured self-heated thermistor as a flow detection sensor. Two different operating modes are presented: a sigma-delta constant temperature operating mode and a transient-temperature based operating mode. Both modes are compared and experimental results showing the performance in both cases are presented.

关键词： Anemometers air flow measurement thermal sigma-delta robot sensors

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Time-coordinated path following of multiple UAVs over time-varying networks using L1 adaptation

Time-coordinated path following of multiple UAVs over time-v...

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作者： Aguiar, A.P. Pascoal, A.M. Kaminer, I. Dobrokhodov, V. Xargay, E. Hovakimyan, N. Cao, C. Ghabcheloo, R. Instituto Superior Técnico Lisbon Portugal Naval Postgraduate School Monterey CA 93943 United States University of Illinois at Urbana-Champaign Urbana IL 61801 United States University of Connecticut Storrs CT 06269 United States Tampere University of Technology Tampere Finland Institute for Systems and Robotics and Electrical Engineering and Computers Instituto Superior Técnico Portugal Department of Mechanical and Astronautical Engineering Naval Postgraduate School United States Department of Mechanical Science and Engineering University of Illinois Urbana-Champaign United States Department of Mechanical Engineering University of Connecticut United States Department of Intelligent Hydraulics and Automation Tampere University of Technology Finland

ISBN: (纸本)9781563479458

Motivated by challenging mission scenarios, this paper tackles the problem of multi-Unmanned Aerial Vehicle (UAV) cooperative control in the presence of time-varying communication networks. Specifically, we address the problem of steering a fleet of UAVs along given paths (path following) so as to meet spatial and/or temporal constraints. One possible scenario is the situation where a fleet of vehicles is tasked to execute collision-free maneuvers under strict spatial constraints and arrive at their final destinations at exactly the same time. The paper builds on previous work by the authors on coordinated path following and extends it to allow for time-varying communication topologies. Path following control in 3D builds on a nonlinear control strategy that is first derived at the kinematic level (outer-loop control). This is followed by the design of an L1 adaptive output feedback control law that effectively augments an existing autopilot and yields an inner-outer loop control structure with guaranteed performance. Multiple vehicle time-critical coordination is achieved by enforcing temporal constraints on the speed profiles of the vehicles along their paths in response to information exchanged over a dynamic communication network. We address explicitly the situation where each vehicle transmits its coordination state to only a subset of the other vehicles, as determined by the communications topology adopted. Further, we consider the case where the communication graph that captures the underlying communication network topology may be disconnected during some interval of time (or may even fail to be connected at any instant of time) and provide conditions under which the complete coordinated path following closed-loop system is stable. Hardware-in-the-Loop (HITL) simulation results demonstrate the benefits of the developed algorithms. ©;2008 by A. P. Aguiar, I. Kaminer, R. Ghabcheloo, A. M. Pascoal, E. Xargay, N. Hovakimyan, C. Cao, V. Dobrokhodov.

关键词： Cooperative communication

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A control method of ankle foot orthosis (AFO) with artificial muscle

A control method of ankle foot orthosis (AFO) with artificia...

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SICE Annual Conference

作者： Masanori Sugisaka Jiwu Wang Hiroshi Tsumura Masashi Kataoka Institute for Physical and Chemical Research Nagoya Japan Department of Mechanical and Electrical Engineering Nippon Bunri University Itiki Oita Japan Graduate School of Information Production and Systems Waseda University Kitakyushu Japan ALife Robotics Company Limited Oita Miyazaki Japan Faculty of Medicine Oita University Oita Japan

ISBN: (纸本)9784907764302

We developed a new ankle foot orthosis (AFO) using artificial muscle. In AFO two pressure sensors are arranged in the bottom of the foot. One is located on the toe and other is located on the heel. The control consists of four control sequences such that (1) when the heel touches down on the floor, the pressure of artificial muscle goes to zero gradually, (2) when the toe touches down on the floor after the touch down of the heel, the pressure of artificial muscle is still off, (3) when the heel leaves from the floor, the pressure of artificial muscle is zero, (4) when the toe leaves from the floor, the pressure of artificial muscle becomes a certain value, hence, the artificial muscle is shortened. From the experimental data of a disabled patient it is revealed that this control law yields the faster walking and the shorter swing length. Also, especially, it is clarified that in the action shown by (2) above the plantar flexion control is very important for early recovery of walking ability. In this paper we focus our attention to the development of a new control law to improve the rehabilitation performance based on the plantar flexion control.

关键词： Control Methods control law muscles Decks Toes Heel plantar flexion Ability to walk artificial

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Vehicle communications: A short survey

Vehicle communications: A short survey

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2007 IADIS International Conference on Telecommunications, Networks and systems, TNS 2007, part of the 1st IADIS Multi Conference on Computer Science and Information systems, MCCSIS 2007

作者： Fernandes, Pedro Nunes, Urbano ISR - Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Polo II Coimbra Portugal

ISBN: (纸本)9789728924409

Inter-vehicle communications (IVC) consists in a real application of vehicular ad-hoc networks (VANET) and is part of Intelligent Transportation systems (ITS). An overview of IVC is presented. To guarantee IVC effectiveness, attention must be paid to one of the most important component of the system: the driver and the way he/her receives crucial information. A brief summary of the communication issues is presented. © MCCSIS 2007 .All right reserved.

关键词： Automobile drivers

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Audio-Visual Speech Processing Framework for Lip Reading

Audio-Visual Speech Processing Framework for Lip Reading

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International Conference on Information and Communication Technologies: From Theory to Applications, ICTTA

作者： Abdulbaset M. Nasr Abd Rahman Ramli Mohammad Hamiruce Shamala K Subramaniam Robotics Lab Institute of advanced technology Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia Department of Computer and Communications Systems Faculty of Engineering Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia Department of Electrical and Electronics Engineering Faculty of Engineering Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia Department of Communication Technology & Networks Faculty of Computer Science and Information Technology Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia

It is well known that speech production and perception process is inherently bimodal consisting of audio and visual components. Recently there has been increased interest in using the visual modality in combination with the acoustic modality for improved speech processing. This field of study has gained the title of audio-visual speech processing. Lip movement recognition, also known as lip reading, is a communication skill which involves the interpretation of lip movements in order to estimate some important parameters of the lips that include, but not limited to, size, shape and orientation. In this paper, we represent a hybrid framework for lip reading which is based on both audio and visual speech parameters extracted from a video stream of isolated spoken words. The proposed algorithm is self-tuned in the sense that it starts with an estimations of speech parameters based on visual lip features and then the coefficients of the algorithm are fine-tuned based on the extracted audio parameters. In the audio speech processing part, extracted audio features are used to generate a vector containing information of the speech phonemes. These information are used later to enhance the recognition and matching process. For lip feature extraction, we use a modified version of the method used by F. Huang and T. Chen for tracking of multiple faces. This method is based on statistical color modeling and the deformable template. The experiments based on the proposed framework showed interesting results in recognition of isolated words.

关键词： Speech processing Image processing Parameter estimation Data mining Feature extraction Robots Computer networks systems engineering and theory Communications technology Computer science

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AI and memory: Studies towards equipping a robot with a sparse distributed memory

AI and memory: Studies towards equipping a robot with a spar...

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IEEE International Conference on robotics and Biomimetics

作者： Mateus Mendes A. Paulo Coimbra Manuel Crisostomo ESTGOH IPC Coimbra ISR-Institute of Systems and Robotics Department of Electrical and ComputerEngineering University of Coimbra Portugal ISR-Institute of Systems and Robotics Department of Electrical and ComputerEngineering University of Coimbra Portugal

ISBN: (纸本)9781424417612;1424417619

Traditional approaches to Artificial Intelligence (AI) and robotics seem only to provide advances at a very slow pace. Many researchers agree that new, different approaches are needed to provide a breakthrough and allow the construction of robots with human-like capacities. Our approach consists in navigating a robot using vision a Sparse Distributed Memory (SDM), a kind of associative memory based on the properties of high dimensional binary spaces, which, in theory, exhibits some human-like behaviours. During learning the robot will store sequences of images in the SDM. During execution the robot will follow the sequence of images that is closest to its current view. Preliminary results show that the memory can store and predict sequences of images with a small error tolerance.

关键词： Artificial intelligence Intelligent robots Humans Brain modeling Orbital robotics Navigation Humanoid robots Neurons Machine intelligence Mathematical model

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A Drowsiness and Point of Attention Monitoring System for Driver Vigilance

A Drowsiness and Point of Attention Monitoring System for Dr...

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International Conference on Intelligent Transportation

作者： Jorge Batista ISR-Institute of Systems and Robotics Department of Electrical Engineering and Computers FCTUC University of Coimbra Coimbra Portugal

This paper presents a framework that combines a robust facial features location with an elliptical face modelling to measure driver's vigilance level. The proposed solution deals with the computation of eyelid movement parameters and head (face) point of attention. The most important facial feature points are automatically detected using a statistically anthropometric face model. After observing the structural symmetry of the human face and performing some anthropometric measurements, the system is able to build a model that can be used in isolating the most important facial feature areas: mouth, eyes and eyebrows. Combination of different image processing techniques are applied within the selected regions for detecting the most important facial feature points. A model based approach is used to estimate the 3D orientation of the human face. The shape of the face is modelled as an ellipse assuming that the human face aspect ratio (ratio of the major to minor axes of the 3D face ellipse) is known. The elliptical fitting of the face at the image level is constrained by the location of the eyes which considerable increase the performance of the system. The system is fully automatic and classifies rotation in all-view direction, detects eye blinking and eye closure and recovers the principal facial features points over a wide range of human head rotations. Experimental results using real images sequences demonstrates the accuracy and robustness of the proposed solution.

关键词： Monitoring Face detection Facial features Humans Robustness Head Eyes Eyelids Performance evaluation Area measurement

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On Maximum Stability Margin Design of Nonlinear Uncertain systems: Fuzzy Control Approach

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Asian Journal of Control 2008年第3期3卷

作者： Chung-Shi Tseng Bor-Sen Chen Huey-Jian Uang the Department of Electrical Engineering of Ming Hsin Institute of Technology Hsin Chu Taiwan. the Department of Electrical Engineering of National Tsing Hua University Hsin Chu Taiwan. Huey-Jian:Uang received the B.S. degree from the Department of Electrical Engineering Feng-Chia University Taichung Taiwan and the M.S. degree and Ph.D. degree from National Tsing-Hua University Hsin-Chu Taiwan all in electrical engineering. He is now an Assistant Professor at the Ming Hsin Institute of Technology and Commerce Hsin-Chu Taiwan. His current research interests include robotics robust control and fuzzy systems.

This paper studies the maximum stability margin design for nonlinear uncertain systems using fuzzy control. First, the Takagi and Sugeno fuzzy model is employed to approximate a nonlinear uncertain system. Next, based on the fuzzy model, the maximum stability margin for a nonlinear uncertain system is studied to achieve as much tolerance of plant uncertainties as possible using a fuzzy control method. In the proposed fuzzy control method, the maximum stability margin design problem is parameterized in terms of a corresponding generalized eigenvalue problem (GEVP). For the case where state variables are unavailable, a fuzzy observer-based control scheme is also proposed to deal with the maximum stability margin for nonlinear uncertain systems. Using a suboptimal approach, we characterize the maximum stability margin via fuzzy observer-based control in terms of a linear matrix inequality problem (LMIP). The GEVP and LMIP can be solved very efficiently via convex optimization techniques. Simulation examples are given to illustrate the design procedure of the proposed method.

关键词： Maximum stability margin fuzzy control GEVP and LMIP

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Retrieving and Exploiting Hand's Orientation in Tabletop Interaction

Retrieving and Exploiting Hand's Orientation in Tabletop Int...

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IEEE International Conference on Multimedia and Expo (ICME)

作者： Joao Carreira Paulo Peixoto Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Portugal

Large displays and hand gestures can be combined to augment the traditional desktop paradigm, allowing for multiple co-located users to interact simultaneously with a single computer, and therefore to engage in computer mediated collaboration activities. Here we introduce a novel technique for recovering the rotation of the hands, adapting a previously developed vision-based interface which we use to extract the users' bare hands from a video stream, taken over a tabletop display. Unlike previous tabletop input devices, ours is focused on capturing holistic hand cues. We argue that these cues, namely the posture and the rotation of the hand, can be an important complement to the fingertips' positions used in most systems of this kind, because we consider they can make the experience more natural and simple for the users. We also present a new interaction technique using these capabilities.

关键词： Mice Hardware Computer displays Application software Computer vision Shape Collaborative software Collaborative work Space technology Robots

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