Error Compensation of Yaw and Pitch Deformation on Roll Angle Measurement

Aiming at the double grating torsion deformation measurement scheme, we study the influence of yaw and pitch angle changes on the roll angle measurement, and propose a corresponding error compensation method. First, the math-ematical model is established by analyzing the relationship between the yaw, pitch deformation and the geometric projection of the grating. The model shows that measurement error is also affected by the magnitude of the roll angle itself. In the experiment, the high precision multi-tooth indexing table is used to simulate the yaw deformation, and the collected data is used for polynomial fitting analysis. Finally, the accuracy of roll angle measurement can be guaranteed within 3.5" after 3-order polynomial compensation.