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1992 IEEE INTERNATIONAL SYMP ON INTELLIGENT CONTROL

作者： RIMON, E BOYD, SP Robotics Laboratory Stanford University Department of Computer Science United States Information Systems Laboratory Stanford University Department of Electrical Engineering United States

ISBN: (纸本)0780305469

Knowledge of the distance between a robot and its surrounding environment is vital for any robotic system. The robot must obtain this information rapidly in order to plan and react in real-time. Our technique first surrounds the robot links and the obstacles by optimal ellipsoids, and then computes the clearance of the links from the obstacles with a generalized distance function. This approach offers an attractive alternative to the widely used technique of computing the distance via polyhedral representation of the robot and the obstacles. In particular, our approach offers a drastic reduction in the complexity of the data structures: each polyhedron, typically represented by a list of its features and their adjacency graph;is replaced by a minimum-volume ellipsoid represented by its center and a symmetric matrix whose dimension is either two or three (the workspace dimension). Moreover, while the computation time of the distance between polyhedra is often a function of their geometrical complexity, computation time in the ellipsoidal case is essentially constant;and becomes even more rapid when it is computed repeatedly along the robot's trajectory. Our method consists of the following two algorithms: The first computes the optimal ellipsoid surrounding a convex polyhedron. The second is an analytic formula for the free margin about one ellipsoid with respect to another, that is computed as a standard eigenvalue problem. An efficient incremental version of the latter algorithm is then proposed. This system has been implemented and preliminary simulation results are provided throughout the paper. © 1992 IEEE.

关键词： Geometry

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The segmented bus: A dynamically segmentable interprocessor communication network for intelligent mobile robot systems

The segmented bus: A dynamically segmentable interprocessor ...

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1992 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 1992

作者： Aras, C.M. Luo, Ren C. Reeves, D.S. Robotics and Intelligent Systems Laboratory Department of Electrical and Computer Engineering United States Department of Computer Science North Carolina State University RaleighNC27695 United States

ISBN: (纸本)0780307372

We propose a new interprocessor communication network, named the Segmented Bus, for multiprocessor message passing computer architectures executing groups of processes with localized communication patterns and time varying computational demands. The control of autonomous robots includes such process sets, making this architecture suitable for the intelligent robot control problem and other control systems with localized and changing message communication patterns. The Segmented Bus also allows dynamic segmentation of the interprocessor communication network for dynamic reconfiguration based on task communication locality. Virtual cut-Through and preemptive circuit switched data transfers are used for inter-segment data transfers on the Segmented Bus. Hardware and protocols for implementing these two techniques are discussed. The performance of the Segmented Bus using the two data transfer techniques is evaluated with simulation and the results are compared to the single bus and the multiple bus in terms of the performance, expandability and the complexity of hardware. © 1992 Institute of Electrical and Electronics Engineers Inc. All rights reserved.

关键词： Data transfer

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Shape recognition by random grasping

Shape recognition by random grasping

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1992 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 1992

作者： Kang, Dukhyun Goldberg, K.Y. Institute for Robotics and Intelligent Systems Computer Science Department University of Southern California Los AngelesCA90059-0273 United States

ISBN: (纸本)0780307372

Our objective is to recognize parts in a structured environment (such as a factory) using inexpensive and widely available hardware. In this paper we consider the class of parts with constant polygonal cross section. We aim to recover the shape of a part's cross section by randomly grasping t,he part with a parallel-jaw gripper and measuring the distance between the jaws (the diameter). Since more than one part may give rise to the same diameter and the diameter sensor may be corrupted by noise due to surface compliance and backlaqh, we use a Bayesian decision procedure to estimate the most probable part. We describe preliminary experiments on synthetic and physical data and report on the sensitivity of recognition time to sensor noise, sensor resolution, and probability threshold. Our experiments suggest that even the most unsophisticated grasp strategy-random grasping-can be sufficient for recognizing parts. © 1992 Institute of Electrical and Electronics Engineers Inc. All rights reserved.

关键词： Intelligent robots

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Continuous smooth path execution for an autonomous guided vehicle (AGV) 21

Continuous smooth path execution for an autonomous guided ve...

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1992 IEEE Region 10 International Conference on Technology Enabling Tomorrow: computers, Communications and Automation towards the 21st Century, TENCON 1992

作者： Zelinsky, A. Dowson, I. Intelligent Robotics Laboratory Department of Computer Science University of Wollongong P.O. Box 1144 WollongongNSW2500 Australia

ISBN: (纸本)0780308492

A method for converting a series of line segments generated by a high-level path planner for an AGV to a combination of continuous smooth curves and straight line paths is presented. Ideally, the straight line path segments should be connected by circular arcs. The AGV's angular velocity along the straight paths is zero and will not smoothly connect the angular velocity moments required to traverse the circular arcs. Therefore, a transition curve (clothoid) needs to be generated to smoothly connect these angular moments. A technique for computing the clothoid transition curves for an AGV to execute is given. The method was implemented on a Macintosh II computer and was used to control a mobile robot. © 1992 IEEE.

关键词： Angular velocity

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ACTIVE DYNAMIC STEREO FOR NAVIGATION 2nd

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2ND EUROPEAN CONF ON computer VISION ( ECCV 92 )

作者： GROSSO, E TISTARELLI, M SANDINI, G University of Genoa Department of Communication Computer and Systems Science Integrated Laboratory for Advanced Robotics (LIRA-Lab) Via Opera Pia 11A Genoa 16145 Italy

ISBN: (纸本)3540554262

Stereo vision and motion analysis have been frequently used to infer scene structure and to control the movement of a mobile vehicle or a robot arm. Unfortunately, when considered separately, these methods present intrinsic difficulties and a simple fusion of the respective results has been proved to be insufficient in practice. The paper presents a cooperative schema in which the binocular disparity is computed for corresponding points in several stereo frames and it is used, together with optical flow, to compute the time-to-impact. The formulation of the problem takes into account translation of the stereo set-up and rotation of the cameras while tracking an environmental point and performing one degree of freedom active vergence control. Experiments on a stereo sequence from a real scene are presented and discussed. © Springer-Verlag Berlin Heidelberg 1992.

关键词： Stereo vision

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Quasi-statically planned self-posture changeability for link system

Quasi-statically planned self-posture changeability for link...

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1992 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 1992

作者： Kaneko, Makoto Tanie, Kazuo Kyushu Institute of Technology Computer Science and System Engineering Fukuoka820 Japan Robotics Department Mechanical Engineering Laboratory Tsukuha Scicncc305 Japan

ISBN: (纸本)0780307372

With a proper combination of compliant and position- controlled joints, a link system can change its posture with keeping contact between link system and environment. This motion is so-called Self-Posture Changing Motion (SPCM). This paper first discusses several key technologies to realize a SPCM with defining it in a general form available for plane contact as well as point contact. A SPCM can be applied for detecting an approximate contact point between a 2-D link system and an unknown object. The second goal of this paper is to explore a scheme capable of providing a closer point to the object's surface. In order to evaluate a computing scheme, Degree-of-Approximation (I).O.A) is newly introduced. This is defined as the distance between a computed point and the nearest point over the object's surface. We finally proposes a scheme which improves D.O.A and provides an exact contact point not only for a sharp-edged object but also for a constant curved object. © 1992 IEEE. All rights reserved.

关键词： Point contacts

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A pictorial index mechanism for model-based matching

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Data and Knowledge Engineering 1992年第4期8卷 309-327页

作者： Grosky, William I. Neo, Peter Mehrotra, Rajiv Computer Science Department Wayne State University Detroit MI 48202 United States Key Plastics Inc. Plymouth MI 48170 40300 Plymouth Road United States Computer Science Department Center for Robotics and Manufacturing Systems University of Kentucky Lexington KY 40506 United States

We are currently developing unified query processing strategies for image databases. To perform this task, model-based representations of images by content are being used, as well as a hierarchical generalization of a relatively new object-recognition technique called data-driven indexed hypotheses. As the name implies, it is index-based, from which its efficiency derives. Earlier approaches to data-driven model-based object recognition techniques were not capable of handling complex image data containing overlapping, partially visible, and touching objects due to the limitations of the features used for building models. Recently, a few data-driven techniques capable of handling complex image data have been proposed. In these techniques, as in traditional databases, iconic index structures are employed to store the image and shape representation in such a way that searching for a given shape or image feature can be conducted efficiently. Some of these techniques handle the insertion and deletion of shapes and/or image representations very efficiently and with very little influence on the overall system performance. However, the main disadvantage of all previous data-driven implementations is that they are main memory based. In the present paper, we describe a secondary memory implementation of data-driven indexed hypotheses along with some performance studies we have conducted. © 1992.

关键词： Data-driven iconic indexing image database model-based matching

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Robotic instrumented complaint wrist

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Journal of Manufacturing science and Engineering, Transactions of the ASME 1992年第1期114卷 120-122页

作者： Xu, Yangsheng Paul, R.P. The Robotics Institute Carnegie Mellon University Pittsburgh PA 15213 United States Department of Computer and Information Science University of Pennsylvania Philadelphia PA 19104 United States

A robotic complaint wrist which combines a passive compliance device and a displacement sensor has been developed and tested. The device provides the necessary flexibility to accommodate transitions between the position control and force control modes, and avoid large impact forces as a robot makes contact with parts, as well as correct positioning errors and allow the relaxation of tolerances in assembly and manufacturing operations. The device installed between a robot arm and end-effector is composed of two parts: a passive compliance device and a sensing mechanism. The passive compliance is provided by a rubber structure;its configuration can be arranged to yield the desired stiffness ratio along and about each axis. The sensing mechanism consists of a six-joint serial linkage with a transducer at each point. The measured deflection is used to actively control the contact forces and compensate for the positioning error during motion and *** this paper, the design features of two prototypes of the device are described. A systematic hybrid position/force control scheme incorporating the device is presented. © 1992 by ASME.

关键词： Errors Deflection robotics End effectors Engineering prototypes Position control Sensors Stiffness Displacement Design Rubber Force control Relaxation (Physics) Linkages Transducers Manufacturing Robots

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On the derivation of geometric constraints in stereo

On the derivation of geometric constraints in stereo

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1992 IEEE computer Society Conference on computer Vision and Pattern Recognition, CVPR 1992

作者： Stewart, C.V. Department of Computer Science New York State Center for Advanced Technology in Automation and Robotics Rensselaer Polytechnic Institute TroyNY12180-3590 United States

ISBN: (纸本)0818628553

Probability density functions (PDFs) are derived for many of the geometric measurements upon which stereo matching techniques are based, including orientation differences between matching line segments or curves, the gradient of disparity, the directional derivative of disparity, and disparity differences between matches. The PDFs resulting from the transformations are used to critically examine many existing stereo techniques. Several techniques based on these PDFs are proposed. © 1992 IEEE.

关键词： Probability density function

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Adaptive control techniques for dynamic visual repositioning of hand-eye robotic systems

Adaptive control techniques for dynamic visual repositioning...

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1992 IEEE Workshop on Applications of computer Vision, WACV 1992

作者： Papanikolopoulos, N.P. Khosla, P.K. Department of Computer Science University of Minnesota 200 Union St. SE MinneapolisMN55455 United States Department of Electrical and Computer Engineering Robotics Institute Carnegie Mellon University PittsburghPA15213 United States

ISBN: (纸本)0818628405

Using active monocular vision for 3-D visual control tasks is difficult since the translational and the rotational degrees of freedom are strongly coupled. The paper addresses several issues in 3-D visual control and presents adaptive control schemes for the problem of robotic visual servoing (eye-in-hand configuration) around a static rigid target. The objective is to move the image projections of several feature points of the static rigid target to some desired image positions. The inverse perspective transformation is assumed partially unknown. The adaptive controllers compensate for the servoing errors, the partially unknown camera parameters, and the computational delays which are introduced by the time-consuming vision algorithms. The authors present a stability analysis along with a study of the conditions that the feature points must satisfy in order for the problem to be solvable. Finally, several experimental results are presented to verify the validity and the efficacy of the proposed algorithms. © 1992 IEEE.

关键词： Degrees of freedom (mechanics)

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