An approach to the computation of a representation of objects with a planar and curved faces using discontinuity features in range images is presented. Edge maps are computed from real laser triangulation images using...
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An approach to the computation of a representation of objects with a planar and curved faces using discontinuity features in range images is presented. Edge maps are computed from real laser triangulation images using local operators and shadow analysis, and then structured into an edge-junction graph embedding and quantitative information. This is achieved by appealing to certain concepts of line-drawing analysis adapted to the three-dimensional nature of range imaging. The edge-oriented method is primarily useful for objects that are well-described by their edges. The main advantage of edge-based descriptions is that no fixed surface primitives are assumed. On the other hand, this scheme can only represent objects without any surface crease edges (such as a sphere) by viewpoint-dependent limb edges. This information may be insufficient for the ensuing high-level task. Thus, a generalization of the description format might include a surface analysis to provide a richer representation.< >
A distributed control system built using a local area network of digital signal processor based controllers is described. By coordinating the single-loop controllers, the system allows the partitioning of different ta...
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A distributed control system built using a local area network of digital signal processor based controllers is described. By coordinating the single-loop controllers, the system allows the partitioning of different tasks on separate microcomputers and offers the advantages of expandability and modularity. Different strategies can be implemented by downloading of software in this distributed control system. Although the architecture of this control system is designed for robot control, the system is generally and fully programmable and does not assume any manipulator characteristics. AT&T DSP32 32-bit, 16-MHz digital signal processors are used in this design. Simulation of the control system software is tested on an IBM-AT with the AT&T DSP32 development tools, and these results are presented.< >
Using a hierarchical approach, an expert system for performing circuit board repair tasks within a robotic workcell has been developed. The new circuit board repair system is rule-based and includes a nonmonotonic inf...
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Using a hierarchical approach, an expert system for performing circuit board repair tasks within a robotic workcell has been developed. The new circuit board repair system is rule-based and includes a nonmonotonic inference engine using forward chaining and nonblocking functions, a database describing a robotic workcell, and rule sets into which repair tasks are implemented. Parallel-processing capability is achieved by using nonblocking functions. Action synthesis is based on matching rules to the given database. The system was programmed in Common LISP on a SUN 3 workstation under UNIX BSD version 4.3 and on a dedicated Symbolics 3600 LISP machine. The development, implementation, and testing of the circuit board repair system are described.< >
An approach to finding the solution equations for simple manipulators is described which enhances the well known method of Paul, Renaud, and Stevenson, by explicitly making use of known decouplings in the manipulator ...
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This paper describes a new approach to decision support based on logic programming. SAGE, Sequence Analysis by Graphical Evaluation, is a both a logic framework and a set of Prolog programs to express and then solve t...
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We propose a two-level hierarchy for planning collision-free trajectories in time varying environments. Global geometric algorithms for trajectory planning are used in conjunction with a local avoidance strategy. Simu...
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The focus of this article is the presentation of the issues involved in the design of a system able to automatically or semi-automatically construct a global, world-centered model of an industrial scene. In a robotic ...
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The problem of curve detection decomposes naturally into two stages: (i) inferring the (discrete) trace and tangent to the curve;and (ii) finding integrals through the resultant tangent field. Orientation selection is...
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An approach to the problem of range image segmentation is described. It is a hybrid of region- and edge-based approaches. It is assumed that the range image of an object, which may be constructed of both curved and pl...
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An approach to the problem of range image segmentation is described. It is a hybrid of region- and edge-based approaches. It is assumed that the range image of an object, which may be constructed of both curved and planar surfaces, is divided into surface primitives which are homogeneous in their intrinsic differential geometric properties and do not contain discontinuities in either depth or surface orientation. The method is based on the computation of the Gaussian and mean curvatures from which a curvature sign map is computed. Two initial edge-based segmentations are also computed from the partial derivatives and depth values. One detects jump edges while the other highlights roof edges. The three image maps are then combined to produce the final range image segmentation. Experimental results for both synthetic and real range data of polyhedral and curved objects have proved the usefulness of the approach. Results for the real data are given.< >
Robot tasks have come to demand flexible sensory-based "intelligent" behavior. The single robot has given way to multiple robots cooperating in three-dimensional dynamic environments which allow them to acco...
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Robot tasks have come to demand flexible sensory-based "intelligent" behavior. The single robot has given way to multiple robots cooperating in three-dimensional dynamic environments which allow them to accomplish complex and intricate tasks. Because of the complex nature of the tasks performed, centralized control is no longer practical; workcells have become centers of distributed computing. This motivates the need for an interprocess communication (IPC) facility which would integrate the individual elements both within and between workcells. A survey of IPC is presented in the context of distributed robotics. To make the survey more meaningful, it is introduced by some remarks about general approaches to communication within a distributed computing environment. A discussion of the main IPC design issues for distributed robotics is included.
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