Patent GB-2524661-A (GB)
Title: Coordinate measurement machine with distance meter used to establish frame of reference
Inventor: BRIDGES ROBERT E
IPC: G01B21/04
Filed: 2015-03-23
Abstract: A portable articulated arm coordinate measuring machine AACMM includes a distance meter to measure 3D coordinates of at least three targets to establish a position and orientation of the articulated arm within a frame of reference established by the at least three targets. A method of operating the AACMM for measuring three-dimensional coordinates of an object in space comprises: providing the AACMM in a AACMM frame of reference having an origin, the AACMM having a manually positionable arm portion, a base, a noncontact measurement device, and an electronic circuit, the arm portion having an opposed first end and second end, the arm portion comprising a plurality of connected arm segments, each of the plurality of connected arm segments having at least one position transducer for producing a plurality of position signals, the first end connected to the base, the noncontact measurement device connected to the second end, an electromagnetic radiation transmitter, and a sensor, the electronic circuit configured to receive the plurality of position signals; providing a first reflective target at a first location having first target three dimensional coordinates in a target frame of reference, a second reflective target at a second location having second target three-dimensional coordinates in the target frame of reference, and a third reflective target at a third location having third target three dimensional coordinates in the target frame of reference, wherein the first location, the second location, and the third location are non-collinear; manually positioning the second end to direct the transmitted electromagnetic radiation to the first target; measuring a first distance to the first target with the noncontact measurement device and measuring a first plurality of position signals; manually positioning the second end to direct the transmitted electromagnetic radiation to the second target; measuring a second distance to the second target with the noncontact measurement device and measuring a second plurality of position signals; manually positioning the second end to direct the transmitted electromagnetic radiation to the third target; measuring a third distance to the third target with the noncontact measurement device and measuring a third plurality of position signals; determining by a processor, relative to the target frame of reference, first origin coordinates and first AACMM orientation angles, the first origin coordinates being three dimensional coordinates of the origin in the target frame of reference and the first AACMM orientation angles being three rotational angles of orientation of the AACMM in the target frame of reference, the first origin coordinates and the first AACMM orientation angles being based at least in part on the first distance, the first plurality of signals, the first three-dimensional coordinates, the second distance, the second plurality of signals, the second three-dimensional coordinates, the third distance, the third plurality of signals, and the third three-dimensional coordinates; and storing the first origin coordinates and the first AACMM orientation angles.