CMM WITH IMPROVED SENSORS
A method of operating an articulated arm CMM is provided. One or more coordinates on an object can be measured with the articulated arm CMM. At least one of the encoders can then be at least partially powered-off. The encoder can then be powered on and one or more coordinates on the same object can be measured without recalibrating the encoder.
1 . A method of operating an articulated arm CMM comprising:
measuring one or more coordinates on an object with an articulated arm CMM;
at least partially powering off at least one encoder in the articulated arm CMM;
powering on said at least one encoder; and
measuring one or more coordinates on said object after powering on said encoder without re-indexing said encoder.
2 . The method of claim 1 , wherein the step of powering off comprises fully powering off said encoder.
3 . The method of claim 1 , further comprising the step of putting the CMM in a sleep mode.
4 . The method of claim 1 , further comprising the step of combining the measured coordinates from before and after the powering off step into a single data set representing the measured object.
5 . An articulated arm CMM comprising:
an articulated arm comprising a plurality of articulated arm members, a coordinate acquisition member at a distal end, and a base at a proximal end;
wherein at least one of the articulation members comprises an absolute encoder.
6 . The articulated arm CMM of claim 5 , wherein the at least one absolute encoder is configured to enter a sleep mode during which it does not measure its position.
7 . The articulated arm CMM of claim 6 , wherein the at least one absolute encoder is powered off during said sleep mode.
8 . The articulated arm CMM of claim 5 , wherein the at least one absolute encoder is configured to enter a mode in which it reads position at a lower frequency.
9 . The articulated arm CMM of claim 5 , wherein the absolute encoder comprises a non-repeating pattern.
10 . The articulated arm CMM of claim 9 , wherein the pattern comprises varying reflective properties.
11 . The articulated arm CMM of claim 9 , wherein the pattern comprises varying translucent properties.
12 . The articulated arm CMM of claim 9 , wherein the pattern comprises varying magnetic properties.
13 . The articulated arm CMM of claim 5 , wherein the arm comprises a plurality of measured axes of rotation and at least one absolute encoder for each measured axis of rotation.
14 . The articulated arm CMM of claim 5 , wherein the absolute encoder consists of more than one readhead.
15 . An articulated arm CMM comprising:
an articulated arm comprising a plurality of articulated arm members, a measuring probe, at a distal end, and a base at a proximal end:
a tilt sensor rigidly connected to the base such that the tilt sensor can detect a tilting angle of the base.
16 . The articulate arm CMM of claim 15 , wherein the arm provides a signal to a user when the tilt of the base changes beyond a threshold amount.
17 . The articulated arm CMM of claim 15 , wherein the arm or an external device compensates the data for tilting sensed by the tilt sensor.
18 . The articulated arm CMM of claim 15 , wherein the arm or an external device flags data taken while the tilt of the base has changed beyond a threshold amount.
19 . A method of operating an articulated arm CMM comprising:
measuring one or more coordinates with an articulated arm CMM;
continuously measuring the tilt of the articulated arm CMM; and
when the measured tilt exceeds a threshold value, performing an action selected from the group consisting of compensating the measured coordinates for the tilt, providing a signal regarding the tilt to a user, and flagging the measured coordinates taken during the tilt.