Westinghouse Electric Corporation

Jeffrey D Taft

James F Ellison

Gerald A Breakey

Casey C Neubauer

Richard S Antoszewski

Jack W Clements

Andrew P Reiman

Sinan G Aksoy

Scott A Upton

Robert A Drisko

James O Seymour, Jr

Frank J Sciulli

A control processor in a robotic system treats optically sensed locations along the path ahead of the tool, which are classified in relation to elapsed distances and identified in 3-D coordinates and 3-axes tool orientation, to apply in real time and under feedforward a control signal representing the error between anticipated tool position and anticipated sensed location on the path. In the process, the anticipated sensed location is obtained by reference to a model made ahead of time with the stored sensed locations grouped as a function of elapsed distances and having a common algebraic feature, such as the slope or the change of slope. A taught path for the robot has been recovered by the control processor also based on elapsed distances and control is related to actual tool position provided by the robot.

Parametric path modeling for an optical automatic seam tracker and real

The image pipeline for a vision system includes a series of digital image processing boards controlled by a computer. A video camera generates from a laser beam reflected from the target surface an RS-170 analog video signal which is converted to a digital signal for processing. Bins of digitizing parameters suitable for several target surface reflectivities are stored in computer memory. The appropriate bin is selected from histogram data of pixel intensity levels generated by one of the image processing boards using digitizing parameters from a reference bin. Improved imaging, especially of black surfaces, is achieved by scanning a laser beam to generate a light stripe over a number of image frames using the digitizing parameters from the selected bin and integrating the data from the successive frames using the image processing boards.

Vision system with adjustment for variations in imaged surface

An image processing system uses the digital expression of the video image of a light stripe derived optically from a seam to create a 1-D signal representative of a one-pixel wide line. The target coordinates for the tool operating on the seam is converted directly into 3-D tool position and orientation from the 1-D signal. Matching with models is effected in real time by comparing symbolic attributes of the graphs built up with the 1-D signal and with standard seams. From such matching is selected the operative corner, or target for the tool.

Image processing system for an optical seam tracker

A look-ahead sensor attached to the its effector end deviates upon each control action upon the robot toward a new position along the seam path. The chord across the seam path from the present effector end to the contemporaneously sensed seam path location is determined and used with the present orientation of the effector end to determine an additional yaw angle compensating for the deviation. As a result, the look-ahead sensor is constantly brought back on track.

Path contriving system for look-ahead sensor in a robotic control system

A control processor in a robotic system treats optically sensed locations along the seam path ahead of the tool, which are classified in relation to elapsed distances and identified in 3-D coordinates and 3-axes tool orientation, to apply in real time and under feedforward a control signal representing the error between anticipated tool position and anticipated sensed location on the path. In the process, the anticipated sensed location is obtained by interpolation between acutally sensed locations. A taught path is recovered from the robot. The control processor operation is also based on elapsed distances and related to actual tool position provided by the robot.

Optical automatic seam tracker and real time control system for an

A method and apparatus for illuminating a target, for example the wall and internal structures of a coal, oil, or gas fired combustion chamber for remote viewing. A coherent light source is used to illuminate the target with illumination of a selected spectral content different from that produced by ambient light resulting from the combustion of the fuel. The coherent light illuminates the target and a narrow band optical filter is placed in front of a viewing camera to filter ambient light but to pass the illuminating source reflected from the target. The coherent light source has a wavelength range of about 422 nm to about 780 nm. Source wavelengths are chosen to be sufficiently long to penetrate particulate laden gases and still be distinguishable from thermal radiation inside the furnace. A human observer may manipulate the laser source and view the target using filter spectacles.

Through flame optical viewing

The present invention includes a surface inspection system with a single light source producing two light stripe sheets projected from different angles onto an inspected surface so that a combined light sheet produces a light stripe image with no shadows results. The two light stripe sheets are created by tangentially reflecting a laser beam off of separate cylindrical reflectors. The light stripe is detected by an imaging system, including a camera having a CCD image array, held at a fixed angle with respect to the light sheet which allows the two-dimensional curvature of the stripe to be detected. The two-dimensional light stripe image is converted into a digital image and processed by linear and logical digital filters that narrow the stripe down to two pixels wide. A coordinate extraction apparatus extracts the coordinates of the bottom row of the pixel image producing a digital representation of the light stripe curve. The sample curve is compared by a computer with a reference curve by obtaining the absolute value of the difference in height of points along the sample and reference curves after alignment and comparing the absolute value to an error or tolerance threshold. Any deviation beyond the fixed tolerance is reported as a surface irregularity defect.

Geometric surface inspection system with dual overlap light stripe

A range finding apparatus includes a pair of spaced apart cameras which provide signals that are digitalized, stored in frame buffers, and provided to a computer that provides a range map of a target object viewed by the cameras. The computer optimizes a disparity function by minimizing a cost functional, thereby finding the range at different points on the surface of the target object based on variations in illumination, reflectivity, and texture.

Range finding method and apparatus

A compact optical apparatus for tracking a path of movement of a tool along a line of travel on a workpiece, includes a light source for providing a collimated light beam, wherein the light source is mounted on the tool adjacent the rear of the tool. A cylindrical reflector is mounted adjacent one side of the tool and is positioned in the path of the collimated light beam to reflect at least a portion of the collimated light beam to project a light stripe on the workpiece in front of the tool. The cylindrical reflector is positioned with respect to the collimated light beam and the line of travel of the tool so that the projected light stripe is substantially bisected by the line of travel. A camera is oriented to face away from the workpiece and is used to generate an image of the light stripe projected on the workpiece. An autocorrelation filter is connected to the camera in situations where the tool causes transient images to be produced on the image, for example, when the tool is a seam welder which produces sparks which travel across the field of view of the camera. The autocorrelation filter is employed to remove the spark trails from the image of the projected light stripe.

Compact optical apparatus for tracking a path of movement of a tool

A vision sensor for tracking includes a light stripe vision sensor for use in harsh environments. This light stripe generator is light source independent and produces a light stripe without the use of lenses. Additionally, the enclosure in which the light stripe generating and detecting means are mounted includes an environmental control system which provides pressurized, conditioned air into the apparatus enclosure in order to control the affects of dust, humidity and temperature variations countered in many working environments. This vision system is particularly well suited for use in welding applications and can be easily used in combination with an industrial manipulator to provide automated vision sensor capabilities.

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Plum Boro, PA, United States of America

Jeffrey D Taft