Disclosed is a system and method for independently evaluating the spatial positional performance of a machine having a movable member, comprising an articulated coordinate measuring machine comprising: a first revolute joint; a probe arm, having a proximal end rigidly attached to the first joint, and having a distal end with a probe tip attached thereto, wherein the probe tip is pivotally mounted to the movable machine member; a second revolute joint; a first support arm serially connecting the first joint to the second joint; and coordinate processing means, operatively connected to the first and second revolute joints, for calculating the spatial coordinates of the probe tip; means for kinematically constraining the articulated coordinate measuring machine to a working surface; and comparator means, in operative association with the coordinate processing means and with the movable machine, for comparing the true position of the movable machine member, as measured by the true position of the probe tip, with the desired position of the movable machine member.

Position feedback control system

A measurement apparatus, system and method for measuring objects which is easily relocatable about the object is described. The system uses an articulated-arm coordinate measuring machine (CMM) and a laser tracker. A retroreflector for use with the laser tracker is located on the arm of the articulated-arm (CMM). A common coordinate frame of reference can be determined for the CMM and the laser tracker so that the CMM can be moved. Also, points hidden from the laser tracker can be measured for example with the CMM.

Apparatus and method for relocating an articulating-arm coordinate measuring machine

A system for producing an assembly comprising at least one component includes at least one 3D metrology system, a workstation processing element, numerical control apparatus and a flexible work cell. The metrology system maps the components for use by the workstation processing element, which electronically displays three-dimensional authority models representative of the components. The workstation processing element compares the as-built models to an electronic display of three-dimensional authority models of the components, and alters a position of at least one of the at least one actual model and the at least one authority model. The workstation processing element then commands the numerical control apparatus to perform a machine operation on the components based upon the comparison. As the numerical control apparatus performs the machine operation on the components, the workstation processing element dynamically displays the actual models such that the electronic display of the actual models is automatically and repeatedly updated.

System and method for producing an assembly by directly implementing three-dimensional computer-aided design component definitions

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 retroflector 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.

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.

Software for improving the accuracy of machines

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.

Method for product acceptance by 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 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

PROBLEM TO BE SOLVED: To solve the problem that large machines, especially, those having working envelopes in excess of fifteen feet, exhibit unacceptable errors because of thermal expansion and mechanical misalignments between 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, and 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.SOLUTION: The present invention uses an interferometric laser tracker or a comparable 3D position sensor to measure the position of a retroreflector attached to an 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.

Thomas W. Pastusak

Papers

Method for product acceptance by improving the accuracy of machines

Scaling machine media for thermal effects to improve machine accuracy

Method for improving accuracy of machines

Verfahren zur verbesserung der genauigkeit von maschinen