System and method for precisely positioning a robotic tool
First Claim
1. An apparatus for precisely positioning a robotic tool relative to a worksite, wherein the worksite has a target located at a fixed position relative thereto, the apparatus comprising:
- (a) a camera, mounted to the robotic tool at an angle, operable to;
(1) focus an image of the target onto a focal plane so that when the robotic tool is at a nominal distance from the worksite, said image appears at a specified position on the focal plane, and to(2) generate a position signal indicating a current position of the robotic tool relative to the worksite, as indicated by an actual position on said focal plane where said image of the target appears;
(b) a system controller, in communication with said camera, operable to(1) determine a parallax corrected position of said image of the target on said focal plane, wherein said parallax corrected position is separated from said specified position for tool distances other than said nominal distance, said parallax corrected position corresponds to parallax free positioning of the robotic tool relative to the worksite, and said parallax corrected position is based on(i) said nominal distance between the robotic tool and the worksite and any variation in distance from said nominal distance,(ii) said angle, and(iii) a focal length of said camera, and(2) generate a position correction signal representing a difference between said current position of the robotic tool relative to the worksite and said desired position of the robotic tool relative to the worksite; and
(c) a positioning mechanism, in communication with said system controller, to reposition the robotic tool relative to the worksite in response to said position correction signal.
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Abstract
A system and method for precisely positioning a robotic tool relative to a worksite, wherein the worksite includes a positioning target located at a fixed position relative thereto is disclosed. A camera coupled to the robotic tool detects the target and generates a position signal representing a current position of the robotic tool relative to the worksite. A system controller receives the position signal and computes a parallax-corrected position based on the distance to the worksite. In addition, the system controller produces a correction signal representing the difference between the parallax-corrected position and the current position. A mechanical arm precisely positions the robotic tool and the worksite relative to each other.
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Citations
16 Claims
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1. An apparatus for precisely positioning a robotic tool relative to a worksite, wherein the worksite has a target located at a fixed position relative thereto, the apparatus comprising:
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(a) a camera, mounted to the robotic tool at an angle, operable to; (1) focus an image of the target onto a focal plane so that when the robotic tool is at a nominal distance from the worksite, said image appears at a specified position on the focal plane, and to (2) generate a position signal indicating a current position of the robotic tool relative to the worksite, as indicated by an actual position on said focal plane where said image of the target appears; (b) a system controller, in communication with said camera, operable to (1) determine a parallax corrected position of said image of the target on said focal plane, wherein said parallax corrected position is separated from said specified position for tool distances other than said nominal distance, said parallax corrected position corresponds to parallax free positioning of the robotic tool relative to the worksite, and said parallax corrected position is based on (i) said nominal distance between the robotic tool and the worksite and any variation in distance from said nominal distance, (ii) said angle, and (iii) a focal length of said camera, and (2) generate a position correction signal representing a difference between said current position of the robotic tool relative to the worksite and said desired position of the robotic tool relative to the worksite; and (c) a positioning mechanism, in communication with said system controller, to reposition the robotic tool relative to the worksite in response to said position correction signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for precisely positioning a robotic tool relative to a worksite, wherein the robotic tool has a camera mounted at an angle thereto, and wherein the worksite has a target located at a fixed position relative thereto, the method comprising the steps of:
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(1) focusing an image of the target onto a focal plane of the camera so that when the robotic tool is at a nominal distance from the worksite, said image appears at a specified position on the focal plane; (2) generating an image position signal representing an actual position on said focal plane where said image of the target appears, said image position signal representing a perceived position of the robotic tool relative to the worksite; (3) computing a parallax-corrected position of said image of the target on said focal plane, said parallax-corrected position representing the focal plane position on which said image must appear for the tool to be in a precise position relative to the worksite, wherein said parallax-corrected position is determined based on the angle of the camera, a focal length of the camera, said nominal distance between the tool and the worksite, and any variation from said nominal distance; (4) computing a difference between said actual position of said image and said parallax-corrected position of said image, said difference representing a difference between said perceived position and said actual position of the robotic tool relative to the worksite; (5) generating a position correction signal based on a difference between said actual position of said image and said parallax-corrected position of said image; and (6) repositioning the robotic tool to said precise position relative to the worksite in response to said position correction signal. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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Specification