12 May 2014 Measurement of six-degree-of-freedom planar motions by using a multiprobe surface encoder
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Abstract
A multiprobe surface encoder for optical metrology of six-degree-of-freedom (six-DOF) planar motions is presented. The surface encoder is composed of an XY planar scale grating with identical microstructures in X - and Y -axes and an optical sensor head. In the optical sensor head, three paralleled laser beams were used as laser probes. After being divided by a beam splitter, the three laser probes were projected onto the scale grating and a reference grating with identical microstructures, respectively. For each probe, the first-order positive and negative diffraction beams along the X - and Y -directions from the scale grating and from the reference grating superimposed with each other and four pieces of interference signals were generated. Three-DOF translational motions of the scale grating Δx , Δy , and Δz can be obtained simultaneously from the interference signals of each probe. Three-DOF angular error motions θ X , θ Y , and θ Z can also be calculated simultaneously from differences of displacement output variations and the geometric relationship among the three probes. A prototype optical sensor head was designed, constructed, and evaluated. Experimental results verified that this surface encoder could provide measurement resolutions of subnanometer and better than 0.1 arc sec for three-DOF translational motions and three-DOF angular error motions, respectively.
© 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)
Xinghui Li, Yuki Shimizu, Takeshi Ito, Yindi Cai, So Ito, Wei Gao, "Measurement of six-degree-of-freedom planar motions by using a multiprobe surface encoder," Optical Engineering 53(12), 122405 (12 May 2014). https://doi.org/10.1117/1.OE.53.12.122405 . Submission:
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