Method and system for determining spatial coordinates with a mobile coordinate measuring machine

Patent metadata

Field	Value
Publication number	US-9897442-B2
Application number	US-201314421802-A
Country	US
Kind code	B2
Filing date	Aug 13, 2013
Priority date	Aug 16, 2012
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

The invention pertains to a method for determining at least one spatial coordinate of a measurement point of a local structure of an object, providing a mobile coordinate measuring machine, the method comprising at least placing the mobile coordinate measuring machine on a surface of the object to be measured, approaching the measurement point with a sensing head, and determining at least one spatial coordinate of the at least one measurement point, characterized by establishing a defined spatial relation between the coordinate measuring machine and the local structure wherein the defined spatial relation is established by means of a mechanical fixation of the coordinate measuring machine to the object, and/or a continuous determination of position and orientation of the coordinate measuring machine relative to the object. The invention furthermore pertains to a mobile coordinate measuring machine and a computer program product for execution of said method.

First claim

What is claimed is:

1. A method for determining at least one spatial coordinate of a measurement point of a local structure of an object, the method comprising:
providing a mobile coordinate measuring machine;
placing the mobile coordinate measuring machine on a surface of the object to be measured;
establishing a defined spatial relation between the coordinate measuring machine and the local structure, wherein the defined spatial relation is established by means of:
a mechanical fixation of the coordinate measuring machine to the object; and/or
a continuous determination of position and orientation of the coordinate measuring machine relative to the object,

approaching the measurement point with a sensing head; and
determining at least one spatial coordinate of the at least one measurement point.

2. The method according to claim 1 , wherein:
positioning the mobile coordinate measuring machine relative to the local structure and maintaining the position, wherein:
the maintaining the position is fully autonomously by positioning means of the mobile coordinate measuring machine; and/or
the maintaining the position is in such a way that a position and orientation of the base and/or the sensor means is continuously determined relative to the local structure and/or relative to an external surveying instrument.

3. The method according to claim 1 , wherein:
the local structure is a hole or a borehole, and approaching the measurement point comprises introducing a stylus of the mobile coordinate measuring machine into the hole basically along a central axis of the hole.

4. The method according to claim 3 , wherein:
said determining of at least one spatial coordinate of the at least one measurement point comprises:
rotating the stylus around a rotational axis;
emitting a first measurement beam to a plurality of measurement points on a wall of the hole;
receiving reflections of the first measurement beam from the plurality of measurement points; and
determining spatial coordinates of the plurality of measurement points based on the reflections.

5. The method according to claim 1 , wherein:
the defined spatial relation has a tolerance smaller than a characteristic resolution of the applied method for determining the at least one spatial coordinate of the at least one measurement point.

6. The method according to claim 1 , wherein:
the position and orientation of the coordinate measuring machine and of the object are determined by at least one external surveying instrument and/or with respect to a reference coordinate system.

7. A coordinate measuring system for determining at least one spatial coordinate of a measurement point of a local structure of an object, comprising a mobile coordinate measuring machine designed for being placed on a surface of the object and comprising:
a base;
sensor means for measuring the measurement point and for generating measurement data, comprising a sensing head; and
a drive mechanism, adapted to drive the sensing head relative to the base for approaching the measurement point, wherein:
means for establishing a defined spatial relation between the mobile coordinate measuring machine and the local structure, wherein the defined spatial relation is achieved by means of:
a mechanical fixation of the mobile coordinate measuring machine to the object; and/or
a continuous determination of a position and orientation of the coordinate measuring machine relative to the object.

8. The coordinate measuring system according to claim 7 , wherein:
the means for establishing the defined spatial relation have a tolerance smaller than a tolerance of the measurement of the sensor means that is at least two orders of magnitude smaller.

9. The coordinate measuring system a according to claim 7 , wherein:
the coordinate measuring machine comprises:
alignment determination means for actively determining a position and orientation of the base and/or of the sensor means relative to the local structure and/or relative to an external surveying instrument; and/or
scanner means for scanning the surface of the object or the local structure;

the sensor means comprise a tactile sensing head being tiltable towards a measuring points by means of a hinge; and/or
the sensor means comprise:
emitter means for emitting an optical measurement beam;

receiver means for receiving reflections of the measurement beam; and
analyzing means for generating the measurement data based on the reflections, wherein spatial coordinates of a measurement point are derivable from the measurement data.

10. The coordinate measuring system according to claim 7 , wherein the coordinate measuring machine comprises damping means for absorption or compensation of vibrations.

11. The coordinate measuring system according to claim 7 , wherein:
the coordinate measuring machine comprises positioning means for autonomous positioning of the base relative to the local structure, the positioning means being designed to position the base relative to the local structure according to the measurement data to centre the base over a central point of the local structure.

12. The coordinate measuring system according to claim 7 , wherein:
placing means, enabling the coordinate measuring machine to maintain a position at the surface autonomously comprising:
connecting means for connecting the placing means fixedly to the surface, wherein the connecting means comprises at least one of an electromagnet, a permanent magnet, a suction pad, and a vacuum cup with a vacuum pump; and/or
standing means for enabling the coordinate measuring machine to stand on the surface autonomously, wherein the standing means:
are linked to the base by at least three legs, wherein each leg comprises a set of leg members as positioning means, wherein the leg members are movable with respect to another in such a way that the base is positionable relative to the local structure; and/or
comprise wheels and/or rollers that are retractable and/or drivable by motor means.

13. The coordinate measuring system according to claim 7 , wherein:
it is designed for determining at least one spatial coordinate of a measurement point of a hole of an object;
the sensing head is a stylus for approaching the measurement point; and
the drive mechanism is adapted to rotate the stylus around a rotational axis and to drive the stylus in such a way that the stylus is capable to move relative to the base along the rotational axis;
wherein the stylus is introducible into the hole in such a way that at least one spatial coordinate of a measurement point of the hole is determinable.

14. The coordinate measuring system according to claim 13 , wherein:
a first measurement beam is emittable from the stylus orthogonally to the rotational axis.

15. The coordinate measuring system according to claim 13 , wherein:
a second measurement beam is emittable, wherein the first measurement beam and the second measurement beam are emitted into opposite directions;
a parallel measurement beam is emittable parallel to the first measurement beam; and/or
a vertical measurement beam is emittable orthogonal to the first measurement beam.

16. The coordinate measuring system according to claim 13 , wherein:
the coordinate measuring machine comprises hole centring means, comprising at least three centring members designed for entering the hole and expanding towards the outer wall of the hole in order to position the base centrally over the hole.

17. The coordinate measuring system according to claim 7 , wherein:
the coordi

Assignees

• Hexagon Technology Ct Gmbh

Inventors

• Pettersson Bo
• Jordil Pascal

Classifications

• G01B21/04 Primary

  by measuring coordinates of points · CPC title

• G01S17/42

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) · CPC title

• G01B11/005

  coordinate measuring machines · CPC title

• G01B11/002

  for measuring two or more coordinates · CPC title

• G01S17/875

  for determining attitude · CPC title