Machine vision system for position sensing
First Claim
1. A system for sensing the position of an end effector on a remotely manipulated robot arm, comprising:
- a manipulator arm having at least two degrees of freedom for displacing an end effector;
an arm control system responsive to input signals generated remotely from the arm, for positioning the arm relative to a stationary work surface;
means for illuminating the work surface in the vicinity of the end effector;
means for generating a video image of the end effector and the illuminated surface;
means for establishing a reference coordinate of the end effector for a known reference position of the arm relative to the work surface;
means for generating a digitized image of at least a portion of the generated video image when the video image includes the reference position;
means for calibrating the digitized image to the video image by associating the reference coordinate of the end effector in the video image with a reference coordinate of the end effector in the digitized image;
means for continually processing changes in the digitized images resulting from changes in the video images accompanying displacement of the arm from the reference position by the arm control system, to continually track the path of movement of the arm; and
means responsive to the means for processing changes, for continually generating an index indicative of the actual coordinate of the end effector relative to the work surface as the arm is displaced along the work surface.
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Accused Products
Abstract
The video image of the end effector (26) and work surface (32) in the vicinity of the end effector is converted into a series of continually generated digitized images (132), which are further processed to detect and track the relative motion between the end effector and the work surface. After calibration (126), whereby an index of coordinates and arm orientation is established for a known positioning of the end effector relative to a known reference feature (28a) on the work surface, the tracking (168) of the motion of the end effector is utilized to continually update the index (104) to indicate the actual coordinate and orientation of the end effector relative to the work surface. The updated index is displayed on a live video monitor (44), and can be used as input to the feedback circuit (94) of the manipulator control system. In another embodiment of the invention, a high resolution monitor (52) displays an image of substantially the entire work surface, and particularly the features of interest, in the nature of a work surface map, and superimposes thereon a visual indication of the location, orientation and movement of the end effector, using the updated index information.
108 Citations
23 Claims
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1. A system for sensing the position of an end effector on a remotely manipulated robot arm, comprising:
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a manipulator arm having at least two degrees of freedom for displacing an end effector; an arm control system responsive to input signals generated remotely from the arm, for positioning the arm relative to a stationary work surface; means for illuminating the work surface in the vicinity of the end effector; means for generating a video image of the end effector and the illuminated surface; means for establishing a reference coordinate of the end effector for a known reference position of the arm relative to the work surface; means for generating a digitized image of at least a portion of the generated video image when the video image includes the reference position; means for calibrating the digitized image to the video image by associating the reference coordinate of the end effector in the video image with a reference coordinate of the end effector in the digitized image; means for continually processing changes in the digitized images resulting from changes in the video images accompanying displacement of the arm from the reference position by the arm control system, to continually track the path of movement of the arm; and means responsive to the means for processing changes, for continually generating an index indicative of the actual coordinate of the end effector relative to the work surface as the arm is displaced along the work surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of sensing the position of an end effector on a remotely manipulated robot arm relative to distinct features on a work surface having a known geometry, comprising the steps of:
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mounting the arm so that the end effector is adjacent the work surface; generating a video image of the end effector and the work surface in the vicinity of the end effector; positioning the end effector at a known reference position relative to a reference feature on the work surface; establishing a reference coordinate for the reference position of the end effector; generating a digitized image of at least a portion of the video image; calibrating the digitized image to the video image such that the reference coordinate of the end effector in the video image and the reference coordinate of the end effector in the digitized image are the same; moving the arm relative to the work surface; continually processing changes in the digitized image as the arm is moved, to continually track the coordinates of the path of movement of the end effector; and displaying an index indicative of the actual coordinate of the end effector as the end effector is displaced from the reference position. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. In a remote manipulator system including an articulated manipulator arm, an end effector on the manipulator arm, a manipulator control system for moving the arm to position the end effector sequentially in a desired relationship relative to discrete features on a work surface, and means mounted for movement with the arm for generating a video image of the work surface including a plurality of features as the arm is moved, the improvement comprising:
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image sampling means for continually capturing a predetermined portion of the video image containing a plurality of features to produce a series of digitized image frames; image conversion means coupled to the image sampling means, for extracting from each digitized image frame, a salient attribute of ach of at least two said features; and tracking means coupled to the image conversion means, for inferring from changes in the salient attributes in the series of digitized frames, the path of movement of the arm relative to the work surface. - View Dependent Claims (21, 22, 23)
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Specification