Coordinate measuring machine (CMM) and method of compensating errors in a CMM

摘要

The present invention relates to a coordinate measuring machine comprising a stationary base, a probe head, at least one linear drive mechanism for moving in a first direction, the linear drive mechanism having a linear guide and a movable member being supported for movement along the guide by bearings. The linear drive mechanism further comprises at least a first pre-calibrated integral sensor-package having at least two displacement sensors each for measuring a distance from the movable member to the guide in a direction being non-parallel with respect to the first direction, wherein the sensed distances indicate a translational displacement of the movable member from an ordinary bearing position in a direction perpendicular to the first direction and a rotational displacement of the movable member.

主权项

1. A coordinate measuring machine for determination of at least one space coordinate of a measurement point on an object to be measured, comprising:
a stationary base; a probe head being moveable relative to the base; at least one linear drive mechanism for provision of movability of the probe head relative to the base in a first direction, the linear drive mechanism including:
a linear guide in the first direction;a movable member being supported for movement along the linear guide by bearings provided between mutually facing surface of the linear guide and the moving member; anda linear measuring instrument for determination of a first drive position of the movable member in the first direction in parallel to the linear guide;a calculation unit for determination of the space coordinate as a function of at least the first drive position;at least a first pre-calibrated integral sensor-package having at least two displacement sensors each being built for measuring a distance from the movable member to the linear guide in a direction being non-parallel with respect to the first direction, in particular bearing distances between mutually facing surfaces of the movable member and the linear guide, wherein:
the first pre-calibrated integral sensor-package comprises a common housing for rigidly joining together the displacement sensors with a precisely known spatial and geometrical relationship of the displacement sensors relative to each other and the first integral sensor package is built modular and forms a one-piece, coherent component in such a way that it is mountable to and removable from the coordinate measuring machine en bloc;the sensed distances indicate a translational displacement of the movable member from an ordinary bearing position in a direction perpendicular to the first direction; and a rotational displacement of the movable member; andthe space coordinate is determined by the calculation unit is further dependent on the indicated displacement.