The goal of the GOFER project is to control the operation of many mobile robots in an indoor environment in order to automate a variety of tasks. This project raises many research issues: man-robot and robot-robot com...
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The goal of the GOFER project is to control the operation of many mobile robots in an indoor environment in order to automate a variety of tasks. This project raises many research issues: man-robot and robot-robot communication systems and protocols, implementation of non-conflicting sensor systems, task-adapted strategy in the use of sensors, sensor fusion, contingency-tolerant motion control, multi-robot motion planning, multi-robot task planning and scheduling. The purpose of the paper is to focus on the integration of software dealing with various aspects of the overall problem. The paper presents a general simulation tool designed to package such software, and to evaluate and compare methods that solve some of the specific problems mentioned above in an unpredictable environment.< >
A system aimed at controlling the actions of mobile robots in an indoor environment is presented. The main issue addressed is reactive planning: the system enables such robots to perform nonelementary tasks in an envi...
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A system aimed at controlling the actions of mobile robots in an indoor environment is presented. The main issue addressed is reactive planning: the system enables such robots to perform nonelementary tasks in an environment that unpredictably demands to adapt the robots' actions. A control system dealing with this problem was implemented in the context of a representative motion task. A demonstration was carried out on one GOFER robot to test how effectively and reliably the system could achieve this task. The control system is composed of a planning module, written in the Action Network formalism, that governs various behaviors implemented with artificial potential fields or other specific control strategies. Both the system implemented and the demonstration are detailed.< >
The authors investigate a path planning approach that consists of concurrently building and searching a graph connecting the local minima of a numerical potential field defined over the robot's configuration space...
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The authors investigate a path planning approach that consists of concurrently building and searching a graph connecting the local minima of a numerical potential field defined over the robot's configuration space. They describe techniques for constructing 'good' potentials and efficient methods for dealing with the local minima of these functions. These techniques have been implemented in fast planners that can deal with single and/or multiple robot systems with few and/or many degrees of freedom. Some experimental results with these planners are described.< >
Considers a theory of planning, sensing and action in which the fundamental building blocks are, in effect, the 'recognizable sets'-that is, the places in the world that the robot can recognize and distinguish...
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Considers a theory of planning, sensing and action in which the fundamental building blocks are, in effect, the 'recognizable sets'-that is, the places in the world that the robot can recognize and distinguish between. To this end the authors observe that viewing the world through sensors, partitions the world into 'perceptual equivalence classes.' The more information the sensors provide, the 'finer' this partition is. Various possible partitions of the world fit into a lattice structure. This lattice structure captures the information or knowledge state about the world. Using this theory the authors develop notions of task-directed planning and show how history can be used to direct actions and gain information. The authors investigate the structure of the recognizability lattice and its relationship to the world. The authors consider how to compute perceptual equivalence classes both from a model, and incrementally, from the world. Finally, the authors investigate mathematical properties that can help the robot generate disambiguating strategies to gain information about the world to accomplish a task.< >
The authors propose a sophisticated control software based on blackboard architecture for dextrous relocation-based manipulation synthesis using robot hands. An analysis of the suitability of such a blackboard archite...
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The authors propose a sophisticated control software based on blackboard architecture for dextrous relocation-based manipulation synthesis using robot hands. An analysis of the suitability of such a blackboard architecture to relocation-based dexterous manipulation is addressed in detail. It is shown that the control software is capable of autonomous decision-making and can provide human-like variable grain-size common-sense reasoning and analysis while performing grasping or manipulation operations using robot hands.< >
The authors present a systematic comparison of three commonly used least-squares based methods that describes the relationship between noise levels, patch sizes and reliability of surface classification in computer vi...
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The authors present a systematic comparison of three commonly used least-squares based methods that describes the relationship between noise levels, patch sizes and reliability of surface classification in computer vision. The different methods were tested on several sets of synthetic and real data. Complete sets of quadric surfaces were tested. In each case the standard deviation of the Gaussian noise ranged from 0 to 0.05. Four different patch sizes were tested in each case representing data from the entire surface, half surface, quarter surface and from a small patch of the surface. Similar tests were made for two different types of real range data, a sphere and a cylinder. Both synthetic and real data showed improvement in the results obtained by using the M-estimate method in the case of gross outlying points.< >
The authors present an algorithm designed to provide a robot-vehicle with sufficient 'intelligence' to be able to optimize its behavior in the light of information while carrying out the task of moving from an...
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The authors present an algorithm designed to provide a robot-vehicle with sufficient 'intelligence' to be able to optimize its behavior in the light of information while carrying out the task of moving from any position and orientation to any other position and orientation. The kinematic and dynamic constraints of a nonholonomic vehicle are included explicitly. It is thus possible to finesse issues concerned with producing planned paths that cannot be achieved in practice by a real vehicle. Some of the maneuvers that this algorithm can support are shown. The algorithm has been designed to allow the inclusion of unmapped obstacles and thus has the potential of being extended to situations where there are multiple moving vehicles.< >
A reference force-tracking impedance control system is proposed, consisting of a conventional impedance controller in the inner-loop and a trajectory modifying controller in the outer-loop for force-tracking. The desi...
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A reference force-tracking impedance control system is proposed, consisting of a conventional impedance controller in the inner-loop and a trajectory modifying controller in the outer-loop for force-tracking. The design of the outer-loop is presented and the stability of the two-loop control system is analyzed. A computationally efficient control algorithm for the inner-loop is suggested. Simulation results are presented. The controller is able to achieve excellent position and force-tracking with unknown environment stiffness and the presence of a burr on the tracking surface.< >
Connected components detection and labeling is an essential step in many image analysis techniques. The efficiency of the connected components labeling algorithm is critical for many image processing and machine visio...
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Connected components detection and labeling is an essential step in many image analysis techniques. The efficiency of the connected components labeling algorithm is critical for many image processing and machine vision applications that require real time response. The advances in the areas of parallel processing and VLSI technology can be exploited in designing hardware algorithms of high speed and throughput. The authors propose a systolic algorithm and architecture for finding connected components in an image. The architecture is simple and can be implemented as a special purpose VLSI chip. Although, the algorithm has a time complexity of O(N/sup 2/), this is in terms of the actual clock cycle which is estimated as 25 nano seconds. The proposed hardware can process a 128*128 image on 0.85 msec and uses 128 processors where as the MPP requires 94.6 msec with 16384 processors. The only special purpose hardware that exists due to X.D. Yang (1988) requires 300 msec to label a 512*512 image which can be accomplished in about 13.5 msec using the authors' proposed hardware.< >
Describes some current work aimed at producing a system which will act as an assistant to engineers doing failure mode effects analysis (FMEA). The particular interest in FMEA is in the design of electrical circuits i...
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Describes some current work aimed at producing a system which will act as an assistant to engineers doing failure mode effects analysis (FMEA). The particular interest in FMEA is in the design of electrical circuits in an automotive context. In the FMEA application, it is important that faults such as short and open circuits (changes in the topology of the circuit) and their effects can be located quickly. The qualitative reasoning technique developed demonstrates how this can be done and also provides a technique for generating additional information, such as the possibility of current flow given a future change to the circuit.< >
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