The Boeing Company

Thomas W Pastusak

Thomas A Greenwood

Gregory Louis Clark

An apparatus coupled with a mechanism and cooperating with the mechanism to locate an end-effector within a predetermined distance of a work site for situating the end-effector with respect to the work site includes: (a) a positioning unit coupled with the end-effector for moving the end-effector an adjustment distance with respect to the workpiece; (b) a sensing unit coupled with the apparatus for sensing extant locus of the end-effector with respect to at least one reference locus; and (c) an error determining device coupled with the sensing unit and the positioning unit; the error determining device determining a difference between the extant locus and the work locus. The positioning unit moves the end-effector in response to the difference indicating signal to reduce the difference.

Apparatus and method for situating a tool with respect to a work site on a workpiece

Large machines, especially those having working envelopes in excess of fifteen feet, exhibit unacceptable errors because of thermal expansion and mechanical misalignments between the axes. The errors have traditionally been minimized by enclosing the machine in a thermal enclosure, by careful calibration, or by mounting a laser interferometer on each axis. These solutions are costly, may require frequent recalibration, and do not correct for small rotations of one axis relative to another axis due to wear etc. The present invention uses an interferometric laser tracker or a comparable 3D position sensor to measure the position of a retroreflector attached to the end effector, e.g. a machine head when the machine comes to rest. A computer compares the measured position to the desired position according to the machine media, and adds the appropriate correction with trickle feed media statements to move the machine to the correct position prior to further machining.

Software for improving the accuracy of machines

Method for improving the accuracy of machines

Large machines, especially those having working envelopes in excess of fifteen feet, exhibit unacceptable errors because of thermal expansion and mechanical misalignments between the axes. The errors have traditionally been minimized by enclosing the machine in a thermal enclosure, by careful calibration, or by mounting a laser interferometer on each axis. These solutions are costly, may require frequent recalibration, and do not correct for small rotations of one axis relative to another axis due to wear etc. The present invention uses an interferometric laser tracker or a comparable 3D position sensor to measure the position of a retroreflector attached to the end effector, e.g. a machine head when the machine comes to rest. A computer compares the measured position to the desired position according to the machine media, and adds the appropriate correction with trickle feed media statements to move the machine to the correct position prior to further machining. The present invention scales the media statements for changes in the part that occur during its manufacture or inspection.

Real-time orientation of machine media to improve machine accuracy

Large machines, especially those having working envelopes in excess of fifteen feet, exhibit unacceptable errors because of thermal expansion and mechanical misalignments between the axes. The present invention uses an interferometric laser tracker or a comparable 3D position sensor to measure the position of a retroreflector attached to the end effector, e.g. a machine head when the machine comes to rest. A computer compares the measured position to the desired position according to the machine media, and adds the appropriate correction with trickle feed media statements to move the machine to the correct position prior to further machining. The present invention scales the media statements for thermal effects in the factory.

Scaling machine media for thermal effects to improve machine accuracy

Product acceptance requires accurate measurement of product features. We augment machine control with true position feedback from an independent measurement system to allow such inspection to occur with conventional machine tools rather than expensive, special purpose, limited versatility Coordinate Measuring Machines.

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Kent, WA, United States of America

Thomas W Pastusak