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2-DIMENSIONAL ROBOT NAVIGATION AMONG UNKNOWN STATIONARY POLYGONAL OBSTACLES

IeeE TRANSACTIONS ON robotics AND AUTOMATION 1993年第1期9卷 96-102页

作者： FOUX, G HEYMANN, M BRUCKSTEIN, A Center for Intelligent Systems Department of Computer Science Technion-Israel Institute of Technology Haifa Israel

We describe an algorithm for navigating a polygonal robot, capable of translational motion, in an unknown environment. The environment contains stationary polygonal obstacles and is bounded by polygonal walls, all of which are initially unknown to the robot. The environment is learned during the navigation process by use of a laser range-finding device, and new knowledge is integrated with previously acquired information. A partial map of the environment is thus obtained. The map contains parts of the obstacles that were ''seen'' by the robot and the free space between them. The obstacles in the map are transformed into a new set or expanded polygonal obstacles. This enables treating the robot as a point instead of a polygon, and the navigation problem is reduced to point navigation among unknown polygonal obstacles. A navigation graph is built from the transformed obstacles in the map. This is a partial visibility graph of the enlarged obstacles. A search is conducted on the graph for a path to the destination. The path is piecewise linear;at its corners, the robot stops, scans its environment, and updates the map, the obstacles, and the planned path. The algorithm is proved to converge to the desired destination in a finite number of steps provided a path to the destination exists. If such a path does not exist, then the navigation process terminates in a finite number of steps with the conclusion that the destination is unreachable.

关键词： Navigation Orbital robotics Robot sensing systems robotics and automation Kinematics Manipulators Motion planning Robust control Robot control Filtering

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ORIENTING POLYGONAL PARTS WITHOUT SENSORS

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ALGORITHMICA 1993年第2-4期10卷 201-225页

作者： GOLDBERG, KY 1. Institute for Robotics and Intelligent Systems Computer Science Department University of Southern California 90089-0273 Los Angeles CA USA

In manufacturing it is often necessary to orient parts prior to packing or assembly. We say that a planar part is polygonal if its convex hull is a polygon. We consider the following problem: given a list of n vertices describing a polygonal part whose initial orientation is unknown, find the shortest sequence of mechanical gripper actions that is guaranteed to orient the part up to symmetry in its convex hull. We show that such a sequence exists for any polygonal part by giving an O(n2 log n) algorithm for finding the sequence. Since the gripper actions do not require feedback, this result implies that any polygonal part can be oriented without sensors.

关键词： robotics PARTS FeeDING PLANNING GRASPING COMPLIANCE MOTION PLANNING WITH UNCERTAINTY COMPLIANT MOTION PLANNING

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Fast motion planning by parallel processing - A review

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JOURNAL OF intelligent & ROBOTIC systems 1997年第1期20卷 45-69页

作者： Henrich, D Institute for Real-Time Computer Systems and Robotics Computer Science Department University of Karlsruhe Kaiserstrasse 12 D-76128 Karlsruhe Germany

One of the many features needed to support the activities of autonomous systems is the ability to plan motion. This enables robots to move in their environment securely and to accomplish given tasks. Unfortunately, the control loop comprising sensing, planning, and acting has not yet been closed for robots in dynamic environments. One reason involves the long execution times of the motion planning component. A solution for this problem is offered by the use of highly parallel computation. Thus, an important task is the parallelization of existing motion planning algorithms for robots so that they are suitable for highly parallel computation. In several cases, completely new algorithms have to be designed, so that a parallelization is feasible. In this survey, we review recent approaches to motion planning using parallel computation. As a classification scheme, we use the structure given by the different approaches to the robot's motion planning. For each approach, the available parallel processing methods are discussed. Each approach is assigned a unique class. Finally, for each research work referenced, a list of keywords is given.

关键词： robotics autonomous systems parallel algorithms parallelism and concurrency motion planning review

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THE CONTROL ARCHITECTURE OF THE PRIAMOS MOBILE SYSTEM

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CONTROL ENGINeeRING PRACTICE 1994年第2期2卷 341-346页

作者： DILLMANN, R KREUZIGER, J WALLNER, F Department of Computer Science University of Karlsruhe Institute for Real-Time Computer Control Systems and Robotics P.O. Box 6980 76128 Karlsruhe Germany

In this paper the control architecture of the PRIAMOS mobile robot system is presented. It consists of four layers which integrate reactive and reflexive components in such a way that the robot can combine fast reaction to unexpected obstacles with predictive behaviour to known components in the environment. A solution for the problem of how to combine control layers which process information on different levels of abstraction and of increasing complexity is discussed. The reflexive part of the control architecture and the modification concerning the motion controller of the mobile robot which was necessary to apply the idea of reflexive navigation is described in more detail. The architecture presented allows motion tasks to be executed in partially unknown or changing environment in an efficient manner. Especially, the time-critical reflexive level is computationally less expensive than in previous approaches.

关键词： intelligent MACHINES NAVIGATION HIERARCHICALLY intelligent CONTROL ARCHITECTURE OBSTACLE AVOIDANCE ROBOTS SENSORS

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REAL-TIME MAP REFINEMENT BY USE OF SONAR AND ACTIVE STEREO-VISION

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robotics AND AUTONOMOUS systems 1995年第1期16卷 47-56页

作者： WALLNER, F DILLMANN, R Institute for Real-Time Computer Systems & Robotics Department of Computer Science University of Karlsruhe P.O. Box 6980 76128 Karlsruhe 1 Germany

A mobile robot that navigates in an unknown or changing environment needs to maintain a dynamic model of its environment in order to update existing knowledge about the world. This paper addresses the problem of how to update a local model of the perceivable environment of a mobile robot and how to produce a description of newly perceived obstacles. A new hybrid concept is presented which combines the advantages of parameter- and grid-based modelling techniques. By introducing local grids that only cover areas where new obstacles are expected, the complexity of the map building process is significantly reduced. Local grids can be used in dynamic environment which was not possible with earlier grid-modelling approaches. The information, grids are constructed from, is provided by ultrasonic range sensors and an active stereo-vision system, Fusing information of both sensor systems is advantageous, especially due to their complementary error characteristics concerning range and angular resolution.

关键词： MOBILE ROBOT ACTIVE SENSING MAP BUILDING SENSOR FUSION

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On generalisation of machine learning with neural-evolutionary computations 3

On generalisation of machine learning with neural-evolutiona...

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3rd International Conference on Computational Intelligence and Multimedia Applications, ICCIMA 1999

作者： Kumar, Rajeev Department of Computer Science Centre for Robotics and Intelligent Systems Birla Institute of Technology and Science Pilani333 031 India

ISBN: (纸本)0769503004

Generalisation is a non-trivial problem in machine learning and more so with neural networks which have the capabilities of inducing varying degrees of freedom. It is influenced by many factors in network design, such as network size, initial conditions, learning rate, weight decay factor, pruning algorithms, and many more. In spite of continuous research efforts, we could not arrive at a practical solution which can offer a superior generalisation. We present a novel approach for handling complex problems of machine learning. A multiobjective genetic algorithm is used for identifying (near-) optimal subspaces for hierarchical learning. This strategy of explicitly partitioning the data for subsequent mapping onto a hierarchical classifier is found both to reduce the learning complexity and the classification time. The classification performance of various algorithms is compared and it is argued that the neural modules are superior for learning the localised decision surfaces of such partitions and offer better generalisation. © 1999 IeeE.

关键词： Degrees of freedom (mechanics)

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Unsupervised learning using the tensor voting graph 5

Unsupervised learning using the tensor voting graph

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5th International Conference on Scale Space and Variational Methods in computer Vision, SSVM 2015

作者： Deutsch, Shay Medioni, Gérard Computer Science Department Institute for Robotics and Intelligent Systems University of Southern California Los Angeles United States

ISBN: (纸本)9783319184609

Tensor Voting is a local, non parametric method that provides an efficient way to learn the complex geometric manifold structure under a significant amount of outlier noise. The main limitation of the Tensor Voting framework is that it is strictly a local method, thus not efficient to infer the global properties of complex manifolds. We therefore suggest constructing a unique graph which we call the Tensor Voting Graph, in which the affinity is based on the contribution of neighboring points to a point local tangent space estimated by Tensor Voting. The Tensor Voting Graph compactly and effectively represents the global structure of the underlying manifold. We experimentally demonstrate that we can accurately estimate the geodesic distance on complex manifolds, and substantially outperform all state of the art competing approaches, especially when outliers are present. We also demonstrate our method’s superior ability to segment manifolds, first on synthetic data, then on standard data sets for a motion segmentation, with graceful degradation in the presence of noise. © IFIP International Federation for Information Processing 2015.

关键词： Tensors

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Autonomous mobile robot teams

Autonomous mobile robot teams

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Conference on intelligent Robots in Factory, Field, Space, and Service, 1994

作者： Agah, Arvin Bekey, George A. Institute for Robotics and Intelligent Systems Computer Science Department University of Southern California Los AngelesCA United States

This paper describes autonomous mobile robot teams, performing tasks in unstructured environments. The behavior and the intelligence of the group is distributed, and the system does not include a central command base or leader. The novel concept of the Tropism-Based Cognitive Architecture is introduced, which is used by the robots in order to produce behavior, transforming their sensory information to proper action. The results of a number of simulation experiments are presented. These experiments include worlds where the robot teams must locate, decompose, and gather objects, and defend themselves against hostile predators, while navigating around stationary and mobile obstacles. © 1993 by Arvin Agah. Published by the American institute of Aeronautics and Astronautics, Inc.

关键词： Navigation

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The potential of thermal imaging to assist winemakers in the detection of downy mildew in Vitis vinifera cv Loureiro

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Procedia computer science 2025年 256卷 78-85页

作者： Fernando Portela Cláudio A. Paredes Joaquim J. Sousa Luís Pádua Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB) University of Trás-os-Montes e Alto Douro (UTAD) 5000-801 Vila Real Portugal PROMETHEUS Research Unit in Materials Energy and Environment for Sustainability Escola Superior Agrária Instituto Politécnico de Viana do Castelo (IPVC) 4900-347 Viana do Castelo Portugal Agronomy Department School of Agrarian and Veterinary Sciences UTAD 5000-801 Vila Real Portugal CISAS—Center for Research in Agrifood Systems and Sustainability IPVC 4900-347 Viana do Castelo Portugal Engineering Department School of Science and Technology UTAD 5000-801 Vila Real Portugal Centre for Robotics in Industry and Intelligent Systems (CRIIS) INESC Technology and Science (INESC-TEC) 4200-465 Porto Portugal Institute for Innovation Capacity Building and Sustainability of Agri-Food Production UTAD 5000-801 Vila Real Portugal

Vineyards represent one of the main crop systems of greatest importance in the world economy, both in terms of the value chain of wine production and in its current expression of generating tradable goods. One of the challenges of grape production is grapevine health, which annually forces the winegrowers to incur fixed costs associated with the prevention and/or treatment of pests and diseases, causing an impact on the environment due to the application of phytosanitary products. Among the various diseases affecting grapevines, downy mildew ( Plasmopara viticola ) stands out, which causes negative impacts throughout the phenological cycle, particularly on leaves by affecting the absorption of photosynthetic pigments and consequent chlorophyll production, ultimately influencing grape yield and quality. Traditional methods for detecting vineyard diseases are often insufficient in crop protection, favoring new forms of a more agile decision support with timely responses. Proximal sensing trough optical sensors can assist in early disease detection. In this context, thermal infrared sensors stand out for their ability to capture changes in thermal response of leaves due to changes in grapevine metabolism and photosynthetic production. This study aims to explore the use of thermal infrared imagery to assess the detection of downy mildew by evaluating temperature variations in the surface of grapevine leaves when compared with non-infected leaves in a vineyard plot of the cv. Loureiro. The effects of temporal and spatial variability on the temperature of mildew-infected vine leaves are reported. A temperature variation of 2.71 °C was found within the same leaf when comparing to infected and non-infect areas. As the infection progresses over time, thermal variation tends to increase.

关键词： proximity sensors thermography disease detection precision viticulture agricultural mechanization automation

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An Extended Kalman Filter for frequent local and infrequent global sensor data fusion

An Extended Kalman Filter for frequent local and infrequent ...

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Conference on Sensor Fusion and Decentralized Control in Autonomous Robotic systems

作者： Roumeliotis, SI Bekey, GA Department of Electrical Engineering Department of Computer Science Institute for Robotics and Intelligent Systems University of Southern California Los Angeles CA 90089-0781 United States

ISBN: (纸本)0819426415

In this paper we compare the performance of a dead-reckoning system for robot navigation to a system using an Extended Kalman Filter (EKF). Dead-reckoning systems are able to approximate position and orientation by feeding data (provided usually by local sensors) to the kinematic model of the vehicle. These systems are subject to many different sources of error. EKFs have the ability to combine the same information and compensate for most of these errors to yield a better estimate. Our simulation results using a simplified kinematic model of Rocky 7 (an experimental rover used in the Mars exploration program at Jet Propulsion Laboratory (JPL)) show that an improvement in performance up to 40% (position error) can be achieved. The local sensors used are: wheel encoders, steering angle potentiometer and gyroscope. Involvement of global sensor measurements can drastically increase the accuracy of the estimate. The lack of GPS or magnetic field on Mars narrows our choices for global localization. Landmarks, such as the sun can be used as natural beacons (reference point for absolute measurements). A sun sensor (SS) that measures the absolute orientation of the rover has been built by Lockheed Martin and now is part of the sensor suite of Rocky 7. The SS measurement is crucial for the estimation filter and we show that the accuracy of the estimation decreases exponentially as the frequency of the SS data fed to the EKF decreases.

关键词： robot localization sun sensor Extended Kalman Filter

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