Method of generating an error map for calibration of a robot or multi-axis machining center
AssigneeFaro Technologoies Inc.
InventorSimon Raab
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Abstract
A novel, portable coordinate measuring machine comprises a multijointed (preferably six joints) manually positionable measuring arm for accurately and easily measuring a volume, which in a preferred embodiment, comprises a sphere ranging from six to eight feet in diameter and a measuring accuracy of 2 Sigma +/−0.005 inch. In addition to the measuring arm, the present invention employs a controller (or serial box) which acts as the electronic interface between the arm and a host computer. The coordinate measuring machine of this invention is particularly useful in a novel method of generating an error map and thus correcting and/or programming the tool path for multi-axis machining centers, particularly robots.
Claims7
A method for generating an error map for multi-axis devices in order to improve the repeatability and/or precision of multi-axis devices comprising the steps of:
- (1) attaching the measurement arm of a passive three dimensional coordinate measuring machine (CMM) having multiple degrees of freedom to a multi-axis device and operating the CMM through a selected 3-dimensional path or operation which emulates the desired proselected programmed path or operation of the multi-axis device;
- (2) developing 3-dimensional data of at least one of (a) position and (b) orientation from step (1) and storing said data, said data defining the actual path or operation of the multi-axis device;
- (3) comparing the actual path or operation to the desired preselected programmed path or operation;
- (4) generating an error map comparing the actual path or operation to the desired preselected programmed path or operation;
- and
- (5) using said error map to improve the repeatability and/or precision of the multi-axis device;
- wherein said CMM includes 6 degrees of freedom, said CMM comprises:
- a movable arm having opposed first and second ends, said arm including a plurality of joints with each joint corresponding to a degree of freedom such that said arm is movable within a selected volume, each of said joints comprising a rotational transfer housing for housing a position transducer, said transducer producing a position signal;
- a support base attached to said first end of said movable arm;
- a probe attached to said second end of said movable arm;
- and
- an electronic circuit for receiving said position signals from said transducer and providing a digital coordinate corresponding to the position of said probe in a selected volume.
Dependencies are inferred from the claim text.