ABSOLUTE SIX-DEGREES-OF-FREEDOM GRATING ENCODER

• Main Authors: WANG, Shengtong, LI, Xinghui
• Format: Patent
• Language: Chinese; English; French
• Published: 24.08.2023
• Subjects: ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVEREDIN A SINGLE OTHER SUBCLASS; MEASURING; MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR; PHYSICS; TARIFF METERING APPARATUS; TESTING

An absolute six-degrees-of-freedom grating encoder. A collimated beam which is generated by a light source module (10) passes through a PBS to generate a beam L1 and a beam L2. The beam L2 is first split into a beam L2-1, a beam L2-2 and a beam L2-3 by means of a composite grating light-splitting module (4). The beam L2-1 generates diffracted light by using a two-dimensional grating region (5-1) of a composite grating (5), and the diffracted light passes through an absolute four-degrees-of-freedom measurement module (20) to measure an absolute pose of the composite grating (5) in θx, θy, θz and z directions. The beam L2-2 and the beam L2-3 respectively enter reference code channels via an X-direction mask and a Y-direction mask. The masks have the same code as the reference code channels, and when being aligned with the code channels, the masks generate a negative pulse, so as to mark a zero position. Beams which are generated by the diffraction of the beam L2-1 and beams which are generated by the beam L1 at