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Steering and Depth Control of an Underwater Robot Using Fuzzy-Like PD Controller

IFAC Proceedings Volumes 2000年第21期33卷 239-244页

作者： I.S. Akkizidis G.N. Roberts P. Ridao J. Batlle Mechatronics Research Centre University of Wales College Newport Allt-yr-yn Campus PO Box 180 Newport South Wales NP9 5XR UK Computer Vision and Robotics Group Institute of Informatics and Applications Edifici Politècnica II Campus Montilivi 7071-Girona SPAIN

The design of a steering and depth control of an underwater vehicle is of interest from the point of view of motion stabilisation as well as manoeuvring performance. The paper describes how a Fuzzy-like Proportional Derivative Controller (Fuzzy-like PD Control) is used to control the course-changing and course-keeping tracking mission and motion of an underwater vehicle. The idea for this type of control architecture is to identify the optimum values, in terms of control performance and robustness, of the parameters of the F-like PD Controller. These parameters may be the scaling factors that are applied in the input/output of the PD part of the controller as well as the fuzzy sets of the fuzzy part of the controller. The values of the scaling factors for the error, the change-of-error and the control output are optimised based on experiments. In this work a method has been developed to control the yaw and depth of an underwater robot in terms of course-changing and course-keeping. The controller is synthesised in two parts. Firstly it is applied in horizontal xy and secondly in vertical xz surface. Experiments in a real environment were planned using the Taguchi Design of Experiments and performed to investigate the capabilities of the controller. The results are presented and analysed extensively.

关键词： Fuzzy like-PD Controller Yaw and Depth Control Taguchi Design of Experiments

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Combining central and peripheral vision for reactive robot navigation

Combining central and peripheral vision for reactive robot n...

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Proceedings of the 1999 IEEE computer Society Conference on computer vision and Pattern Recognition (CVPR'99)

作者： Argyros, Antonis A. Bergholm, Fredrik Computer Vision and Robotics Lab Crete Greece

ISBN: (纸本)769501494

In this paper, we present a new method for vision-based, reactive robot navigation that enables a robot to move in the middle of the free space by exploiting both central and peripheral vision. The robot employs a forward-looking camera for central vision and two side-looking cameras for sensing the periphery of its visual field. The developed method combines the information acquired by this trinocular vision system and produces low-level motor commands that keep the robot in the middle of the free space. The approach follows the purposive vision paradigm in the sense that vision is not studied in isolation but in the context of the behaviors that the system is engaged as well as the environment and the robot's motor capabilities. It is demonstrated that by taking into account these issues, vision processing can be drastically simplified, still giving rise to quite complex behaviors. The proposed method does not make strict assumptions about the environment, requires very low level information to be extracted from the images, produces a robust robot behavior and is computationally efficient. Results obtained by both simulations and from a prototype on-line implementation demonstrate the effectiveness of the method.

关键词： computer vision

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Combining central and peripheral vision for reactive robot navigation

Combining central and peripheral vision for reactive robot n...

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Conference on computer vision and Pattern Recognition (CVPR)

作者： A.A. Argyros F. Bergholm Computer Vision and Robotics Laboratory ICS/FORTH Crete Greece Computational Vision and Active Perception Laboratory Stockholm Sweden

In this paper we present a new method for vision-based, reactive robot navigation that enables a robot to move in the middle of the free space by exploiting both central and peripheral vision. The robot employs a forward-looking camera for central vision and two side-looking cameras for sensing the periphery of its visual field. The developed method combines the information acquired by this trinocular vision system and produces low-level motor commands that keep the robot in the middle of the free space. The approach follows the purposive vision paradigm in the sense that vision is not studied in isolation but in the context of the behaviors that the system is engaged as well as the environment and the robot's motor capabilities. It is demonstrated that by taking into account these issues, vision processing can be drastically simplified still giving rise to quite complex behaviors. The proposed method does not make strict assumptions about the environment, requires very low level information to be extracted from the images, produces a robust robot behavior and is computationally efficient. Results obtained by bath simulations and from a prototype on-line implementation demonstrate the effectiveness of the method.

关键词： Robot vision systems Robot sensing systems Orbital robotics Cameras Navigation Machine vision Data mining Robustness Computational modeling Virtual prototyping

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Face model adaptation with active tracking

Face model adaptation with active tracking

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IEEE International Conference on Image Processing

作者： Lijun Yin A. Basu Computer Vision and Robotics Research Laboratory Department of Computing Science University of Alberta Edmonton AB Canada

A system for face model adaptation combining active tracking is presented. Input from an active camera is used for MPEG4 model based coding. First, the background is compensated considering a moving camera (tilt or pan). Second, the talking face is segmented from the compensated background using fusion of frame differences. A morphological filter is then applied to make the system less sensitive to noise. Third, Hough transform and deformable template coupled with color information are exploited to detect the facial features, e.g., eyes, mouth. Fourth, a wireframe model is adapted to the extracted face by an extended dynamic mesh. The feasibility of the proposed system is demonstrated using several real active video sequences.

关键词： Adaptation model Face detection Cameras MPEG 4 Standard Filters Colored noise Facial features Eyes Mouth Data mining

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Shape recognition and vision-based robot control by shape morphing

Shape recognition and vision-based robot control by shape mo...

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International Conference on Information Intelligence and Systems

作者： R. Singh R.M. Voyles D. Littau N.P. Papanikolopoulos Artificial Intelligence Robotics and Vision Laboratory Department of Computer Science and Engineering University of Minnesota Minneapolis MN USA

The article presents a unified approach for object recognition and recognition based control of robotic interactions with objects. The approach is based on morphing the shape of objects. The morph of one object to another is treated as a deformation and is defined such that it can be quantified using a physics based model. This quantification serves as a dissimilarity measure and is used for shape recognition. By storing the views that represent the grasp positions for different object, the proposed framework is used to identify the desired end position a robot needs to attain for interacting with the given object. Furthermore, the images synthesized during the morph define a view based trajectory, starting with the view defining the initial robot-object orientation to the view defining the desired robot-object orientation. We propose a technique where these synthetic images are used to control the motion of a PUMA 560 eye-in-hand manipulator to execute alignment and grasping tasks. The proposed approach does not require complete calibration information, obviates manual feature selection and correspondence, can provide smooth trajectories, and needs a single image for each object (in a 4-DOF formulation). Potential applications range from recognition and positioning with respect to partially occluded or deformable objects as well as planning robotic grasping based on human demonstration.

关键词： Shape control Robot control Shape measurement Object recognition Physics Deformable models Motion control Manipulators Calibration Humans

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Microcalcification evaluation in computer assisted diagnosis for digital mammography

Microcalcification evaluation in computer assisted diagnosis...

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作者： Martí, Joan Batlle, Joan Cuffí, Xevi Español, Josep Computer Vision and Robotics Group Campus de Montilivi s/n University of Giroria 17071 Girona Spain Department of Oncology Univ. Hospital Dr. Josep Trueta Avda. de França s/n 17007 Girona Spain

In order to develop applications for visual interpretation of medical images, the early detection and evaluation of microcalcifications in digital mammograms is very important since their presence is often associated with a high incidence of breast cancers. Accurate classification into benign and malignant groups would help improve diagnostic sensitivity as well as reduce the number of unnecessary biopsies. The challenge here is the selection of the useful features to distinguish benign from malignant micro calcifications. Our purpose in this work is to analyse a microcalcification evaluation method based on a set of shape-based features extracted from the digitised mammography. The segmentation of the microcalcifications is performed using a fixed-tolerance region growing method to extract boundaries of calcifications with manually selected seed pixels. Taking into account that shapes and sizes of clustered microcalcifications have been associated with a high risk of carcinoma based on different subjective measures, such as whether or not the calcifications are irregular, linear, vermiform, branched, rounded or ring like, our efforts were addressed to obtain a feature set related to the shape. The identification of the parameters concerning the malignant character of the microcalcifications was performed on a set of 146 mammograms with their real diagnosis known in advance from biopsies. This allowed identifying the following shape-based parameters as the relevant ones: Number of clusters, Number of holes, Area, Feret elongation, Roughness, and Elongation. Further experiments on a set of 70 new mammograms showed that the performance of the classification scheme is close to the mean performance of three expert radiologists, which allows to consider the proposed method for assisting the diagnosis and encourages to continue the investigation in the sense of adding new features not only related to the shape.

关键词： Calcification (biochemistry)

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The mapping of texture on VR polygonal models 2

The mapping of texture on VR polygonal models

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2nd International Conference on 3-D Digital Imaging and Modeling, 3DIM 1999

作者： Laurendeau, Denis Bertrand, Nathalie Houde, Régis Computer Vision and Systems Laboratory Department of Electrical Engineering and Computer Engineering Laval University QuebecQCG1K 7P4 Canada Robotics Division Hydro Quebec Research Institute VarennesQCJ3X 1S1 Canada

ISBN: (纸本)0769500625

The paper addresses the problem of choosing automatically, and without user intervention, the best possible 2D image that should be used to map as a texture on polygons of a geometric model of complex scenes made of several objects. The geometric models and the texture data are obtained separately: the models are built from range data while the texture information is obtained from 2D color images of the scene. The system does not make any assumption on the way the texture data has been acquired. Texture selection results are presented for an indoor scene. © 1999 IEEE.

关键词： Image texture

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Planning of regrasp operations

Planning of regrasp operations

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IEEE International Conference on robotics and Automation (ICRA)

作者： S.A. Stoeter S. Voss N.P. Papanikolopoulos H. Mosemann Artificial Intelligence Robotics and Vision Laboratory Department of Computer Science and Engineering University of Minnesota Minneapolis MN USA Institute for Robotics and Process Control Technical University of Braunschweig Germany

Robotic manipulators in contemporary work-cells are often incapable of solving even simple pick-and-place operations. More specifically, most systems require each object to be supplied in the same and pre-defined way. Introducing regrasping to the production cycle relaxes the constraints imposed on supply mechanisms. Regrasping describes the operation that must be performed whenever an object's pick-up grasp is incompatible with its put-down grasp. The paper presents a novel approach to solve the regrasp problem for robots equipped with parallel-jaw end-effecters. The proposed method first evaluates the object's possible grasps and placements. These are subsequently combined to form grasp-placement-grasp triples. A regrasp sequence leading from the pick-up to the put-down grasp is generated by searching through the resulting space of compatible grasp-placement-grasp triples. The algorithm takes kinematic and geometric constraints of both the manipulator and the objects into account. Computational concerns are addressed by subdividing the calculation into an off-line and a fast online phase.

关键词： Intelligent robots Robot vision systems Belts Path planning Artificial intelligence Laboratories computer science Process control Manipulators Production

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Shape recognition and vision-based robot control by shape morphing

Shape recognition and vision-based robot control by shape mo...

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1999 International Conference on Information Intelligence and Systems, ICIIS 1999

作者： Singh, Rahul Voyles, Richard M. Littau, David Papanikolopoulos, Nikolaos P. Artificial Intelligence Robotics and Vision Laboratory Department of Computer Science and Engineering University of Minnesota MinneapolisMN55455 United States Bio-Informatics Division Exelixis Pharmaceuticals 280 E. Grand Avenue So. San FranciscoCA94080 United States

ISBN: (纸本)0769504469

In this paper we article presents a unified approach for object recognition and recognition based control of robotic interactions with objects. The approach is based on morphing the shape of objects. The morph of one object to another is treated as a deformation and is defined such that it can be quantified using a physics based model. This quantification serves as a dissimilarity measure and is used for shape recognition. By storing the views that represent the grasp positions for different object, the proposed framework is used to identify the desired end position a robot needs to attain for interacting with the given object. Furthermore, the images synthesized during the morph define a view based trajectory, starting with the view defining the initial robot-object orientation to the view defining the desired robot-object orientation. We propose a technique where these synthetic images are used to control the motion of a PUMA 560 eye-in-hand manipulator to execute alignment and grasping tasks. The proposed approach does not require complete calibration information, obviates manual feature selection and correspondence, can provide smooth trajectories, and needs a single image for each object (in a 4-DOF formulation). Potential applications range from recognition and positioning with respect to partially occluded or deformable objects as well as planning robotic grasping based on human demonstration. © 1999 IEEE.

关键词： Object recognition

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The mapping of texture on VR polygonal models

The mapping of texture on VR polygonal models

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International Conference on 3D Imaging, Modeling, Processing, Visualization and Transmission (3DIMPVT)

作者： D. Laurendeau N. Bertrand R. Houde Department of Electrical Engineering and Computer Engineering Computer Vision and Systems Laboratory Laval University QUE Canada Robotics Division Hydro-Quebec Research Institute (IREQ) Varennes QUE Canada

关键词： Virtual reality Layout Solid modeling computer vision Color computer graphics Rendering (computer graphics) Cameras Laboratories Data engineering

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