Absolute diameter measurement arm
First Claim
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1. A method of determining absolute diameter of an object on a rotary table, comprising:
- having an assembly formed of (i) a rotary table on a base, and (ii) a support tower on the base and carrying a horizontal measurement arm with a measurement probe end, tracking the measurement probe end of the horizontal measurement arm to obtain a position in three-dimensional space of the measurement probe end of the horizontal measurement arm;
using the horizontal measurement arm, measuring a plurality of points around a circumference of a subject object on the rotary table;
for each measured point, determining a respective corrected point by applying a measurement arm correction to the measured point, the measurement arm correction being based on the tracked and obtained position of the measurement probe end of the measurement arm; and
applying the determined corrected points in a multi-point polygon model and determining absolute diameter of the subject object.
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Abstract
A measurement apparatus and corresponding method can be used to measure an absolute diameter of a part in a shop floor environment. A tracker such as a laser tracker monitors a position of a probe end of a measurement arm of the apparatus. The position measured by the laser tracker can be used directly account for errors in the apparatus such as, for example, positioning errors of the measurement arm. The position monitoring of the tracking device eliminates complex apparatus calibrations and calculations used for previous devices.
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Citations
19 Claims
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1. A method of determining absolute diameter of an object on a rotary table, comprising:
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having an assembly formed of (i) a rotary table on a base, and (ii) a support tower on the base and carrying a horizontal measurement arm with a measurement probe end, tracking the measurement probe end of the horizontal measurement arm to obtain a position in three-dimensional space of the measurement probe end of the horizontal measurement arm; using the horizontal measurement arm, measuring a plurality of points around a circumference of a subject object on the rotary table; for each measured point, determining a respective corrected point by applying a measurement arm correction to the measured point, the measurement arm correction being based on the tracked and obtained position of the measurement probe end of the measurement arm; and applying the determined corrected points in a multi-point polygon model and determining absolute diameter of the subject object. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of calibrating measurements by a horizontal measurement arm, comprising:
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given a high precision rotary table on a base, a support tower on the base carrying a horizontal measurement arm, and a tracker configured to track a measurement probe end of the horizontal measurement arm to obtain a position in three-dimensional space of the measurement probe end of the horizontal measurement arm; determining a measurement arm error based on the tracked and obtained position of the measurement probe end of the horizontal measurement arm; using the determined measurement arm error to effectively measure a plurality of corrected points around a circumference of a subject object on the rotary table with the horizontal measurement arm such that an absolute radius of the subject object is able to be determined by applying the plurality of corrected points in a multi-point polygon model. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An apparatus for measuring absolute diameter of an object on a rotary table, comprising:
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a stable base with a substantially flat surface, the base including vibration-isolating mounts to isolate the stable base from ambient vibrations; a precision rotary table mounted to the flat surface of the stable base; a support tower mounted to the flat surface of the stable base, the support tower substantially perpendicular to the flat surface; a horizontal measurement arm mounted to the support tower substantially parallel to the flat surface and configured to move towards and away from a centerline of rotation of the precision rotary table, the horizontal measurement arm configured to measure a distance of a precision gauge head on a probe end of the horizontal measurement arm from the centerline of rotation; a tracker mounted to the stable base and configured to obtain a position in three-dimensional space of the probe end of the horizontal measurement arm; and a controller configured to; i) determine a measurement arm correction based on the tracked and obtained position of the probe end of the measurement arm; ii) determine a plurality of corrected points by applying a measurement arm correction to each of a plurality of measured points, the measured points being measured by the horizontal measurement arm around a circumference of a subject object on the rotary table, and the measurement arm correction being based upon the position in three-dimensional space of the probe end of the measurement arm; and iii) determine an absolute radius of the object by applying the plurality of corrected points in a multi-point polygon model. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification