High-precision displacement measurement considering angular crosstalk for six-degree-of-freedom grating encoder

High-precision position and orientation measurement plays a crucial role in modern engineering and scientific fields, finding applications in areas such as advanced manufacturing, aerospace, and medical technology. Grating encoders are stable and highly accurate position and orientation measurement solutions, particularly well-suited for multi-degree-of-freedom high-precision measurement scenarios. <br/> <br/> This paper addresses the modeling and compensation of crosstalk errors resulting from grating angle variations in a previously designed six-degree-of-freedom grating encoder for position and orientation measurement. The six-degree-offreedom grating encoder consists of components such as a light source module, reference and measurement gratings, an angle measurement module, and a displacement measurement module. The deflection of the grating affects the interference signal for displacement measurement. The emitted light beam from the light source undergoes diffraction by the measurement grating, using for measuring three degrees of freedom (angles). The interference between the diffracted light from the measurement grating and the reference grating is detected by the displacement measurement module, using for measuring three degrees of freedom (displacements). The traditional grating displacement measurement does not consider the influence of rotation on the laser phase. This paper innovatively models the influence of rotation on the laser phase, which can compensate the displacement settlement, and the ultra-high precision displacement measurement can be obtained.