Coordinate measuring machine and method for operating a coordinate measuring machine

Patent metadata

Field	Value
Publication number	US-10145664-B2
Application number	US-201615295905-A
Country	US
Kind code	B2
Filing date	Oct 17, 2016
Priority date	Apr 17, 2014
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

A coordinate measuring machine including a workpiece support for mounting a workpiece to be measured; a mechanism for moving a sensor in a first coordinate direction and a second coordinate direction perpendicular thereto. The mechanism includes: a first measurement slide guided in the first coordinate direction along two parallel guides arranged on opposite sides of the workpiece support. The first measurement slide spans the support. The first slide is driven via a first drive, which drives the first slide along a first guide of the guides, and is driven via a second drive, which drives the first slide along the second of the guides; a second measurement slide guided movably in the second coordinate direction along the first measurement slide. The second slide is assigned a position measuring system, via which the position of the second measurement slide relative to the first measurement slide can be determined; a controller, which actuates the first and second drive. The controller includes a force feedforward control, which, depending on the detected position (xactual) of the second measurement slide and depending on a setpoint acceleration (asetpoint) to be set of the first measurement slide, brings about an actuation of the first drive and/or of the second drive in such a way that the torques which as a result of the acceleration of the first measurement slide by the first drive and by the second drive relative to a rotation axis (Rz) which is perpendicular to the first and second coordinate directions at least partly or completely compensate for one another.

First claim

What is claimed is:

1. A coordinate measuring apparatus comprising
a workpiece support configured for mounting a workpiece to be measured;
a sensor;
a mechanism configured to move said sensor in at least a first coordinate direction (y) and a second coordinate direction (x) perpendicular to said first coordinate direction;
said mechanism for moving said sensor including
a first guide and a second guide arranged in parallel on opposite sides of said work piece support;
a first measurement slide configured to be guided in said first coordinate direction (y) along said parallel first and second guides;
said first measurement slide spanning said workpiece support;
a first drive configured to drive said first measurement slide along said first guide;
a second drive configured to drive said first measurement slide along said second guide;
a second measurement slide configured to be guided movably in the second coordinate direction (x) along said first measurement slide;
a positioning measuring system assigned to said second measurement slide and configured to determine a position (x actual ) of said second measurement slide relative to said first measurement slide;

a controller configured to actuate at least said first drive and said second drive; and,
said controller including a force feedforward control, which, depending on said determined position (x actual ) of said second measurement slide and depending on a setpoint acceleration (a setpoint ) to be set of said first measurement slide, is configured to cause an actuation of at least one of said first drive and said second drive in such a way that the torques which occur as a result of the acceleration of said first measurement slide by said first drive and by said second drive relative to a rotation axis (R z ) which is perpendicular to said first coordinate direction (y) and said second coordinate direction (x) at least partly or completely compensate for one another.

2. The coordinate measuring machine of claim 1 , wherein:
said first drive includes a first drive regulating circuit;
said second drive includes a second drive regulating circuit; and,
said force feedforward control is configured to ascertain at least one of a first force feedforward control value (I L-feedforward ) configured to be applied to said first drive regulating circuit of said first drive and a second force feedforward control value (I R-feedforward ) configured to be applied to said second drive regulating circuit of said second drive.

3. The coordinate measuring machine of claim 2 , wherein at least one of said first force feedforward control value (I L-feedforward ) and said second force feedforward control value (I R-feedforward ) is a current value which is applied to a current regulator of the corresponding one of said first drive regulating circuit and said second drive regulating circuit.

4. The coordinate measuring machine of claim 2 , wherein said force feedforward control is configured to ascertain at least one of said first force feedforward control value (I L-feedforward ) from the product of the setpoint acceleration (a setpoint ) and a first proportionality factor (C L-actual ) and said second force feedforward control value (I R-feedforward ) from the product of said setpoint acceleration (a setpoint ) and a second proportionality factor (C R-actual ).

5. The coordinate measuring machine of claim 4 , wherein:
said first proportionality factor (C L-actual ) is stored in the form of a first fixed value (C L1 ) assigned to said first proportionality factor (C L-actual ) for a first position (x 1 ) of said second measurement slide and is stored in the form of a second fixed value (C L2 ) assigned to said first proportionality factor (C L-actual ) for a second position (x 2 ) of said second measurement slide, wherein said first proportionality factor (C L-actual ) is ascertained using a present position (x actual ) of said second measurement slide by linear interpolation or linear extrapolation from the first fixed value (C L1 ) assigned to the first proportionality factor (C L-actual ) and the second fixed value (C R2 ) assigned to the first proportionality factor (C L-actual ); and/or,
said second proportionality factor (C R-actual ) is stored in the form of a first fixed value (C R1 ) assigned to said second proportionality factor (C R-actual ) for a first position (x 1 ) of said second measurement slide and is stored in the form of a second fixed value (C R2 ) assigned to said second proportionality factor (C R-actual ) for a second position (x 2 ) of said second measurement slide, wherein said second proportionality factor (C R-actual ) is ascertained using a present position (x actual ) of said second measurement slide by linear interpolation or linear extrapolation from said first fixed value (C R1 ) assigned to said second proportionality factor (C R-actual ) and said second fixed value (C R2 ) assigned to said second proportionality factor (C R-actual ).

6. The coordinate measuring machine of claim 2 further comprising:
a first regulating circuit including a first position regulator and a first speed regulator;
said first drive regulating circuit is part of said first regulating circuit; wherein,
a reference variable of the first drive regulating circuit is formed by the sum of the output of said first speed regulator and of said first force feedforward control value (I L-feedforward ) or is formed only by an output of the said first speed regulator;
a reference variable of the first speed regulator is formed by the output of said first position regulator; and,
a reference variable of the first position regulator is formed by a setpoint position (y setpoint ).

7. The coordinate measuring machine of claim 6 , wherein said reference variable of said second drive regulating circuit is formed exclusively by said second force feedforward control value (I R-feedforward ).

8. The coordinate measuring machine of claim 6 , wherein a reference variable of the second drive regulating circuit is formed by a sum of an output (I L-setpoint ) of said first speed regulator and of said second force feedforward control value (I R-feedforward ).

9. The coordinate measuring machine of claim 6 , wherein said mechanism includes a second position measuring system configured to determine a first position measurement value (y L-actual ) of said first measurement slide relative to said first guide; and, wherein a signal fed back to said first position regulator is said first position measurement value (y L-actual ) of the first measurement slide and a signal fed back to the first speed regulator is a time derivative of said first position measurement value (y L-actual ).

10. The coordinate measuring machine of claim 6 , further comprising:
a second regulating circuit including a second position regulator and a second speed regulator;
said second drive regulating circuit of the second drive being part of said second regulating circuit;
wherein, a reference variable of said second drive regulating circuit is formed by a sum of the output (I R-setpoint ) of said second speed regulator and of said second force feedforward control value (I R-feedforward ); and,
a reference variable of said second speed regulator is formed by the output (v R-setpoint ) of the second position regulator.

11. The coordinate measuring machine of claim 10 , wherein:
said mechanism includes a second position measuring system configured to determine a first position measurement value (y L-actual ) of said first measurement slide relative to said first guide, and a third position measuring system configured to determine a second position measurement value (y R-actual ) of said f

Assignees

• Zeiss Carl Industrielle Messtechnik Gmbh

Inventors

• Grupp Guenter
• Bernhardt Ralf
• Bendzulla Klaus
• Moser Gerd

Classifications

• G05B19/401

  characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes (G05B19/19 takes precedence) · CPC title

• G05B2219/37193

  Multicoordinate measuring system, machine, cmm · CPC title

• G01B5/008 Primary

  using coordinate measuring machines · CPC title

• G01B21/04

  by measuring coordinates of points · CPC title