Method and apparatus for improving measurement accuracy of a portable coordinate measurement machine
First Claim
1. A method for improving the measurement accuracy of a portable coordinate measurement machine (CMM) which measures the position of an object in a selected volume, the CMM including a manually positionable articulated arm having opposed first and second ends, said arm including a at least five rotary joints such that said articulated arm has at least five degrees of freedom, a measurement probe attached to a first end of said articulated arm and an electronic circuit which receives the position signals from transducers in said arm and which provides a digital coordinate corresponding to the position of the probe in a selected volume comprising:
- sensing an error in the angular measurement of at least one transducer associated with a rotary joint, said error being caused by deformation of a portion of said articulated arm when said arm is placed under a load, said deformation causing an error in the measurement made by the CMM ; and
correcting said error in response to said deformation the angular measurement.
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Abstract
A method for improving the measurement accuracy of a portable coordinate measurement machine which comprises an articulated arm having jointed arm segments is presented. This method includes sensing deformation of a portion of the articulated arm when the arm is placed under a load, this deformation causing an error in the measurement made by the CMM, and correcting such error in response to the sensed deformation.
167 Citations
36 Claims
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1. A method for improving the measurement accuracy of a portable coordinate measurement machine (CMM) which measures the position of an object in a selected volume, the CMM including a manually positionable articulated arm having opposed first and second ends, said arm including a at least five rotary joints such that said articulated arm has at least five degrees of freedom, a measurement probe attached to a first end of said articulated arm and an electronic circuit which receives the position signals from transducers in said arm and which provides a digital coordinate corresponding to the position of the probe in a selected volume comprising:
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sensing an error in the angular measurement of at least one transducer associated with a rotary joint, said error being caused by deformation of a portion of said articulated arm when said arm is placed under a load, said deformation causing an error in the measurement made by the CMM ; and
correcting said error in response to said deformation the angular measurement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification