Method 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 an articulated arm having opposed first and second ends, said arm including 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 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.
0 Assignments
0 Petitions
Accused Products
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.
-
Citations
106 Claims
-
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 an articulated arm having opposed first and second ends, said arm including 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 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. - 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, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50)
-
-
49. The method of claim 195 wherein said at least one of said rotary joints comprises at least seven rotary joints.
-
51. A portable coordinate measurement machine (CMM) which measures the position of an object in a selected volume, the CMM including an articulated arm having opposed first and second ends, said arm including 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:
-
means for sensing 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
means for correcting said error in response to said deformation. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100)
-
-
101. A portable coordinate measurement machine (CMM) which measures the position of an object in a selected volume, the CMM including an articulated arm having opposed first and second ends, said arm including at least one rotary joint, 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 wherein at least one of said rotary joints includes a periodic pattern of a measurable characteristic, at least one read head spaced from and in communication with said pattern, said pattern and said read head being positioned within said joint so as to be rotatable with respect to each other, and at least one sensor which measures relative movement in said periodic pattern with respect to said at least one read head, comprising:
-
means for using said at least one sensor for sensing 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
means for correcting said error in response to said deformation. - View Dependent Claims (102, 103, 104)
-
-
105. A portable coordinate measurement machine (CMM) which measures the position of an object in a selected volume, the CMM including an articulated arm having opposed first and second ends, said arm including a plurality of rotary joints, 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 wherein at least two of said plurality of rotary joints each includes a periodic pattern of a measurable characteristic, at least two read heads spaced from and in communication with said pattern, said pattern and said at least two read heads being positioned within said joint so as to be rotatable with respect to each other, comprising:
-
using said at least two read heads in each of said at least two rotary joints to sense 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.
-
-
106. 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 an articulated arm having opposed first and second ends, said arm including a plurality of rotary joints, 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 wherein at least one of said rotary joints includes a periodic pattern of a measurable characteristic, at least one read head spaced from and in communication with said pattern, said pattern and said read head being positioned within said joint so as to be rotatable with respect to each other, and at least one sensor which measures relative movement in said periodic pattern with respect to said at least one read head comprising:
-
using said at least one sensor for sensing 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.
-
Specification