This paper describes a real-time hierarchical system that fuses data from vision and touch sensors to improve the performance of a coordinate measuring machine (CMM) used for dimensional inspection tasks. The system c...
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ISBN:
(纸本)0819426415
This paper describes a real-time hierarchical system that fuses data from vision and touch sensors to improve the performance of a coordinate measuring machine (CMM) used for dimensional inspection tasks. The system consists of sensory processing, world modeling, and task decomposition modules. It uses the strengths of each sensor-the precision of the CMM scales and the analog touch probe and the global information provided by the low resolution camera-to improve the speed and flexibility of the inspection task. In the experiment described, the vision module performs all computations in image coordinate space. The part's boundaries' are extracted during an initialization process and then the probe's position is continuously updated as it scans and measures the part surface. The system fuses the estimated probe velocity and distance to the part boundary in image coordinates with the estimated velocity and probe position provided by the CMM controller. The fused information provides feedback to the motion controller as it guides the touch probe to scan the part. We also discuss integrating information from the vision system and the probe to autonomously collect data for 2-D to 3-D calibration, and work to register Computer Aided Design (CAD) models with images of parts in the workplace.
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 fe...
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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.
The Oak Ridge National Laboratory (ORNL) has demonstrated, evaluated, and deployed a telerobotic approach for the remote retrieval of hazardous and radioactive wastes from underground storage tanks. The telerobotic sy...
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ISBN:
(纸本)0819426415
The Oak Ridge National Laboratory (ORNL) has demonstrated, evaluated, and deployed a telerobotic approach for the remote retrieval of hazardous and radioactive wastes from underground storage tanks. The telerobotic system, built by Spar Aerospace Ltd., is capable of dislodging and removing sludge and gravel-like wastes without endangering the human operators through contact with the environment. Working in partnership with Washington University, ORNL has implemented an Event Based Planner/Function Based Sharing control (FBSC) as an integral part of their overall telerobotic architecture. These aspects of the system enable the seamless union of the human operator and an autonomous controller in such a way to emphasize safety without any loss of performance. The cooperation between ORNL, Spar, and Washington University requires an open and modular control software architecture to enable the parallel development of various components of the system. controlShell has been used as the underlying software architecture to help meet these criteria of generality and modularity.
The potential of the new language of Java is explored in the development of a decentralised target tracking simulator. Three particular features of the Java language prompted this initial investigation, namely that it...
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ISBN:
(纸本)0819426415
The potential of the new language of Java is explored in the development of a decentralised target tracking simulator. Three particular features of the Java language prompted this initial investigation, namely that it is fully object-oriented, graphical user interfaces (GUIs) may be simply constructed, and it, is Internet compatible. In the context of this paper, the full power of Java's object-oriented design is harnessed to reflect the inherent modularity of decentralised tracking systems. This enables, for example, tracks with their associated information structures, and platforms with their associated tracks, to be encapsulated within advanced data structures, or classes. An easy-to-build GUI, based on Java's Abstract Windowing Toolkit (AWT), permits the end-user to rapidly configure a test scenario by selecting simulation variables from pop-up menus, such as the number of sensor platforms, the number of targets, and the type of target trajectory. Additionally, Java's Internet compatibility allows the simulation, in principle, to be accessed remotely. Development work on the Java tracking simulator is described, and illustrated in terms of pseudo-code and screen snapshots. We conclude that in terms of our long-range goal of constructing a simulator that can aid the investigation of decentralised systems under a range of world scenarios and operating conditions, Java shows considerable promise.
Modeling of Autonomous Mobile Robots (AMRs) is sought to enable the designers to investigate various aspects of the design before the actual implementation takes place. Simulation techniques are undoubtedly enriching ...
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ISBN:
(纸本)0819426415
Modeling of Autonomous Mobile Robots (AMRs) is sought to enable the designers to investigate various aspects of the design before the actual implementation takes place. Simulation techniques are undoubtedly enriching the design tools, by which the designer would be able to vary the design parameters as appropriate until achieving some optimal performance point. Although they are general purpose, multimedia tools, especially authoring tools, cant give the AMR designer some degree of assistance in fulfilling his simulation task as fast as possible. This rapid prototyping tool is rather cost effective, and allow the designer to interactively manipulate his design in simple steps. In this paper, a multimedia environment has been constructed to enable designers to simulate AMRs in order to investigate aspects concerning their kinematics and dynamics. It is also sought that these design experiences can be gathered and categorized in a tutoring system that could be used by practitioners and students enrolled in highly technical courses such as robotics. The rich multimedia environment can assist the learner in so many ways by devising examples, suggesting solutions and design tradeoffs that have been experienced before.
Virtual Reality has become a tool for use in many areas of research. We have designed and built a VR system for use in range data fusion and visualization. One major VR tool is the CAVE. This is the ultimate visualiza...
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ISBN:
(纸本)0819426415
Virtual Reality has become a tool for use in many areas of research. We have designed and built a VR system for use in range data fusion and visualization. One major VR tool is the CAVE. This is the ultimate visualization tool, but comes with a large price tag. Our design uses a unique CAVE whose graphics are powered by a desktop computer instead of a larger rack machine making it much less costly. The system consists of a screen eight feet tall by twenty-seven feet wide giving a variable field-of-view currently set at 160 degrees. A Silicon Graphics Indigo2 MaxImpact with the Impact Channel Option is used for display. This gives the capability to drive three projectors at a resolution of 640x480 for use in displaying the virtual environment and one 640x480 display for a user control interface. This machine is also the first desktop package which has built-in hardware texture mapping. This feature allows us to quickly fuse the range and intensity data and other multi-sensory data. The final goal is a complete 3D texture mapped model of the environment. A dataglove, magnetic tracker, and spaceball are to be used for manipulation of the data and navigation through the virtual environment. This system gives several users the ability to interactively create 3D models from multiple range images.
This paper describes a new semi-autonomous, calibration-free system which integrates a user-friendly graphical interface, several cameras, a laser pointer mounted on a two-axis pan/tilt unit, and a six degree-of-freed...
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ISBN:
(纸本)0819426415
This paper describes a new semi-autonomous, calibration-free system which integrates a user-friendly graphical interface, several cameras, a laser pointer mounted on a two-axis pan/tilt unit, and a six degree-of-freedom robot. The details of the system will be discussed in reference to the problem of coating a workpiece of unknown geometry that is positioned arbitrarily with respect to the robot and the vision sensors. The remote user specifies the region of the workpiece that is to be coated simply by ''pointing'' and ''clicking'' on the region of interest as it appears in a single image on the user's computer monitor. By means of a simple and robust control strategy, the laser pointer mounted on the pan/tilt unit is autonomously actuated to a user-specified number of approximate positions in the region of the surface of interest. This is used to create compatible maneuver objectives in the participating vision sensors. Then, using the method of camera-space manipulation, the robot is controlled to make several passes across the region. Regardless of the geometry of the workpiece, the manipulated nozzle always remains perpendicular to the surface at a user-specified distance from the surface, Upon completion of the coating process, the laser pointer is again actuated to pass through a specified number of points on the :new surface. This information is used to make a very precise inference of the thickness of the build-up of the coat that has been applied. If the coat is not sufficiently thick, the robot makes more passes as required. The paper also presents experimental results of the high accuracy of position and orientation control of the manipulated tool, as well as the depth inference of the surface coat applied.
The authors address the development of a coherent framework suitable for the treatment of the heterogeneous multisensorfusion problem, in the context of a robotic environment. The analysis, is based on a geometric de...
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The authors address the development of a coherent framework suitable for the treatment of the heterogeneous multisensorfusion problem, in the context of a robotic environment. The analysis, is based on a geometric description of the robotic environment, and concentrates on parameterizable features of the assumed rigid dynamic objects of interest present in the environment. A quantitative representation of a sensor's inherent ability to extract pertinent information from the environment is stressed. A highly efficient, flexible, and fault-tolerant, decentralizedsensorfusion architecture based on a linear information type structure is presented and compared with previous work in this area. The inclusion of techniques to cope with generalized spatial and temporal uncollocation, along with conclusive discussions on the most appropriate level in the fusion structure for these alignment procedures to be performed, represent the principal contribution.< >
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