System for characterizing manual welding operations on pipe and other curved structures

Abstract

A system for characterizing manual welding exercises and providing valuable training to welders that includes components for generating, capturing, and processing data. The data generating component further includes a fixture, workpiece, at least one calibration device having at least two point markers integral therewith, and a welding tool. The data capturing component further includes an imaging system for capturing images of the point markers and the data processing component is operative to receive information from the data capturing component and perform various position and orientation calculations.

1 . A system for characterizing welding operations, comprising:
 (a) a data generating component, wherein the data generating component further includes:
 (i) a fixture, wherein the geometric characteristics of the fixture are predetermined; 
 (ii) a workpiece adapted to be mounted on the fixture, wherein the workpiece includes at least one joint to be welded, wherein the vector extending along the joint to be welded defines an operation path, and wherein the operation path is linear, curvilinear, circular, or a combination thereof; 
 (iii) at least one calibration device, wherein each calibration device further includes at least two point markers integral therewith, and wherein the geometric relationship between the point markers and the operation path is predetermined; and 
 (iv) a welding tool, wherein the welding tool is operative to form a weld at the joint to be welded, wherein the welding tool defines a tool point and a tool vector, and wherein the welding tool further includes a target attached to the welding tool, wherein the target further includes a plurality of point markers mounted thereon in a predetermined pattern, and wherein the predetermined pattern of point markers is operative to define a rigid body; and 
   (b) a data capturing component, wherein the data capturing component further includes an imaging system for capturing images of the point markers; and   (c) a data processing component, wherein the data processing component is operative to receive information from the data capturing component and then calculate:
 (i) the position and orientation of the operation path relative to the three-dimensional space viewable by the imaging system; 
 (ii) the position of the tool point and orientation of the tool vector relative to the rigid body; and 
 (iii) the position of the tool point and orientation of the tool vector relative to the operation path. 
   
     
     
         2 . The system of  claim 1 , wherein the imaging system further includes a plurality of digital cameras. 
     
     
         3 . The system of  claim 2 , wherein at least one filter is incorporated into the optical sequence for each of the plurality of digital cameras for permitting light from only the wavelengths which are reflected or emitted from the point markers for improving image signal-to-noise ratio. 
     
     
         4 . The system of  claim 2 , wherein the imaging system further includes at least one dynamic region of interest viewable by the plurality of digital cameras, wherein the dynamic region of interest is determined by use of previously known positions for the rigid body, and wherein image information is gathered and processed only from within the dynamic region of interest. 
     
     
         5 . The system of  claim 2 , wherein the plurality of digital cameras includes at least one digital camera positioned above the workpiece and at least one digital camera positioned below the workpiece. 
     
     
         6 . The system of  claim 1 , wherein the workpiece comprises a pipe. 
     
     
         7 . The system of  claim 1 , wherein the position and orientation of the operation path is calibrated using at least two point markers integral to a calibration device which is placed at a known translational and rotational offset to the fixture, and wherein the fixture holds the workpiece at a known translational and rotational offset to the operation path. 
     
     
         8 . The system of  claim 1 , wherein the position and orientation of the operation path is calibrated using at least two point markers located on a fixture that holds the workpiece at a known translational and rotational offset to the operation path. 
     
     
         9 . The system of  claim 1 , wherein the operation path is non-linear, wherein the position and orientation of the operation path in three-dimensional space may be mapped using a calibration device that includes at least two point markers, and wherein the operation path dictates the placement of the calibration device at multiple, different points thereon. 
     
     
         10 . The system of  claim 9 , wherein the operation path is circular. 
     
     
         11 . The system of  claim 1 , wherein the position and orientation of the operation path undergoes a predetermined translational and rotational offset from its original calibration plane based on predetermined sequence steps included in the overall system operation. 
     
     
         12 . The system of  claim 1 , wherein the position and orientation of the operation path, or a predetermined segment thereof, relative to the three-dimensional space viewable by the imaging system is obtained from a three-dimensional CAD model, the coordinate system of which is known relative to the coordinate system of the imaging system. 
     
     
         13 . The system of  claim 12 , wherein the three-dimensional CAD model contains a definition of linear or curvilinear points which define the operation path segment. 
     
     
         14 . The system of  claim 12 , wherein at least three calibration points are located on both the three-dimensional CAD model and on the fixture. 
     
     
         15 . The system of  claim 14 , wherein a position and orientation shift is applied to the three-dimensional CAD model by measuring the position of the at least three calibration points on the fixture with the imaging system and then comparing the measurements to the original calibration points of the three-dimensional CAD model. 
     
     
         16 . The system of  claim 1 , wherein the position and orientation of the operation path is made up of one or more operation path segments that form a chain, and wherein consecutive segments share an operation path point at the end of one segment and the start of the next segment. 
     
     
         17 . The system of  claim 1 , wherein calibration of the tool point and tool vector of the welding tool is performed using two or more point markers integrated into a removable calibration device, and wherein the point markers in the calibration device are located along a tool vector that has a known offset to the tool point of the welding tool. 
     
     
         18 . The system of  claim 1 , wherein calibration of the tool point of the welding tool is performed by inserting the tip of the welding tool into a calibration device, the position and orientation of which relative to the workpiece is predetermined. 
     
     
         19 . The system of  claim 18 , wherein the system calculates values for at least one of tool position, orientation, velocity, and acceleration with respect to the operation path, wherein these values are then compared to predetermined preferred values to determine deviations from known and preferred procedures, and wherein such deviations are used for at least one of assessing skill level, providing feedback for training, assessing progress toward a skill goal, and quality control purposes. 
     
     
         20 . The system of  claim 1 , wherein the point markers defining the rigid body are affixed to the welding tool in a multi-faceted configuration that accommodates a wide range of rotation and orientation changes of the welding tool when in use. 
     
     
         21 . The system of  claim 1 , wherein the point markers defining the rigid body are affixed to the welding tool in a spherical configuration that accommodates a wide range of rotation and orientation changes of the welding tool when in use. 
     
     
         22 . The system of  claim 1 , wherein the passive or active point markers are affixed to the welding tool in a ring configuration that accommodates a wide range of rotation and orientation changes of the welding tool when in use. 
     
     
         23 . The system of  claim 1 , wherein the system calculates values for at least one of tool position, orientation, velocity, and acceleration with respect to the operation path, wherein these values are then compared to predetermined preferred values to determine deviations from known and preferred procedures, and wherein such deviations are used for at least one of assessing skill level, providing feedback for training, assessing progress toward a skill goal, and quality control purposes. 
     
     
         24 . The system of  claim 1 , wherein the fixture includes a frame;
 wherein the frame at least partially surrounds the workpiece;   wherein the frame includes a plurality of digital cameras mounted thereon; and   wherein each digital camera captures images of the workpiece from a different angle.