Position measuring apparatus and working apparatus using the same

• US 6,671,650 B2
• Filed: 02/19/2002
• Issued: 12/30/2003
• Est. Priority Date: 03/05/2001
• Status: Active Grant

• Current Assignee: Mitutoyo Corporation
• Original Assignee: Mitutoyo Corporation
• Inventors: Sugita, Kozo, Matsumoto, Masakazu, Ogura, Katsuyuki
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Sun, Xiuqin
• Application Number:
  US10/076,654
• Publication Number:
  US 20020123858A1
• Time in Patent Office: 679 Days
• Field of Search: 702/152, 702/33, 702/99, 702/95, 702/105, 702/167, 702/150-153, 702/157-159, 702/168, 702/FOR.144, 702/FOR-146, 702/FOR.156, 702/FOR.170, 701/26, 364/559, 337/02, 335/02, 335/03, 73/17.9, 73/18.1
• US Class Current: 702/152
• CPC Class Codes: G01B 21/045 Correction of measurements G01B9/02055 takes precedence

Abstract

An object of the invention is to provide a position measuring apparatus which can execute a stable accuracy assurance at a high accuracy against a deterioration with age and a temperature fluctuation of the apparatus while making a correction of an existing volumetric measuring accuracy effective. In order to achieve the object, in accordance with the present invention, in a position measuring apparatus which measures a target position within a specified coordinate space with respect to a predetermined reference surface (4) on the basis of a coordinate system so as to compensate errors, there is provided a detector (18) for measuring whether or not a change is occurred in a relation with respect to the reference surface (4), in a movement executed by a moving machine (8), and there is further provided with an error corrector (20) for correcting at least any one of a compensation parameter compensating a positional coordinates by an error compensator (16) and a positional coordinate compensated by the error compensator (16), on the basis of an amount of change of a relation measured by the detector (18), in the case that the change is occurred.

Claims

1. A position measuring apparatus comprising:

a target position detector for detecting a target position in a coordinate space with respect to a predetermined reference surface;

a moving machine moving in accordance with a predetermined relation with respect to the reference surface so as to move said target position detector for the purpose of detecting the target position by said target position detector;

a positional coordinate computer for computing a positional coordinate of the target position on the basis of a data such as a displacement of said moving machine;

a position coordinate measuring mechanism constituted by said target position detector, said moving machine and said positional coordinate computer;

a memory classifying geometrical errors on the basis of a positional coordinate measured by said position coordinate measuring mechanism and storing compensation parameters determined from the respective classified errors;

an error compensator for reading out the compensation parameters so as to compensate the errors; and

the target position within a specified coordinate space being measured on the basis of a coordinate system,

wherein the position measuring apparatus comprises;

a detector, comprising a reference side angle meter and a measurement side angle meter, for measuring whether or not a change is occurred in a relation with respect to said reference surface, in a movement executed by said moving machine; and

an error corrector for correcting at least any one of the compensation parameter compensating the positional coordinates by said error compensator and the positional coordinate compensated by said error compensator in order to remove an influence given to the positional coordinate computed by the positional coordinate computer in correspondence to the relation between the movement executed by said moving machine and the reference surface, on the basis of an amount of change of the relation measured by said detector, in the case that the change is occurred.

2. A position measuring apparatus as claimed in claim 1, wherein said coordinate system is an xyz rectangular coordinates system in which said coordinate system is extended in vertical, horizontal and height directions.

3. A position measuring apparatus as claimed in claim 2, wherein said moving machine comprises:

a horizontal direction moving machine for moving in conformity with or in parallel to an x axis;

a vertical direction moving machine for moving in conformity with or in parallel to a y axis; and

a height direction moving machine for moving in conformity with or in parallel to a z axis, and

said detector is provided in any one of said vertical direction moving machine, said horizontal direction moving machine and said height direction moving machine.

4. A position measuring apparatus as claimed in claim 1, wherein said moving machine comprises:

a vertical direction moving machine constituted by a straight guide provided on the reference surface and a vertical direction moving mechanism capable of moving along said guide;

a horizontal direction moving machine constituted by a straight guide mounted to a top of said vertical direction moving machine and provided in a direction parallel to the reference surface and orthogonal to the movement direction of the vertical direction moving machine, and a horizontal direction moving mechanism moving along said guide; and

a height direction moving machine constituted by a rod-liked member mounted to said horizontal direction moving machine and provided with said target position detector at a tip, and a height direction moving mechanism moving said rod-liked member in a direction orthogonal to the reference surface,

the vertical direction moving machine moves said target position detector on a specified straight line on the reference surface,

the horizontal direction moving machine moves within a surface orthogonal to the movement direction of said vertical direction moving machine and in parallel to the reference surface,

the height direction moving machine has a predetermined relation with respect to the reference surface by moving in a direction orthogonal to the reference surface, and

said detector is constituted by a reference side angle meter provided on a guide of the vertical direction moving machine and a measurement side angle meter provided in the vertical direction moving mechanism.

5. A position measuring apparatus as claimed in claim 1, wherein said angle meter is a biaxial angle level.

6. A position measuring apparatus as claimed in claim 1, wherein said angle meter is a laser angle level.

7. A position measuring apparatus as claimed in claim 1, further comprising a memory for saving an amount of change of the relation measured by said detector, wherein said detector is detachably provided in the position measuring apparatus.

8. A working apparatus comprising the position measuring apparatus as claimed in claim 1.

9. A position measuring apparatus comprising:

a target position detector for detecting a target position in a coordinate space with respect to a predetermined reference surface;

a moving machine moving in accordance with a predetermined relation with respect to the reference surface so as to move said target position detector for the purpose of detecting the target position by said target position detector;

a positional coordinate computer for computing a positional coordinate of the target position on the basis of a data such as a displacement of said moving machine;

a position coordinate measuring mechanism constituted by said target position detector, said moving machine and said positional coordinate computer;

a memory classifying geometrical errors on the basis of a positional coordinate measured by said position coordinate measuring mechanism and storing compensation parameters determined from the respective classified errors;

an error compensator for reading out the compensation parameters so as to compensate the errors; and

the target position within a specified coordinate space being measured on the basis of a biaxial rectangular coordinates system,

wherein the position measuring apparatus comprises;

a detector for measuring whether or not a change is occurred in a relation with respect to said reference surface, in a movement executed by said moving machine; and

an error corrector for correcting at least any one of the compensation parameter compensating the positional coordinates by said error compensator and the positional coordinate compensated by said error compensator in order to remove an influence given to the positional coordinate computed by the positional coordinate computer in correspondence to the relation between the movement executed by said moving machine and the reference surface, on the basis of an amount of change of the relation measured by said detector, in the case that the change is occurred.

10. A position measuring apparatus as claimed in claim 9, wherein an amount of change of the relation measured by said detector includes a pitching error and a yaw error with respect to an axis in a specified linear direction.

11. A position measuring apparatus as claimed in claim 9, wherein said angle meter is a biaxial angle level.

12. A position measuring apparatus as claimed in claim 9, wherein said angle meter is a laser angle level.

13. A position measuring apparatus as claimed in claim 9, further comprising a memory for saving an amount of change of the relation measured by said detector, wherein said detector is detachably provided in the position measuring apparatus.

14. A working apparatus comprising the position measuring apparatus as claimed in claim 9.