Structure Optimization Research Of Linear Grating Sensor

Linear grating sensor is mainly used for closed-loop feedback control of CNC machine tools and precision instrument. Its accuracy directly determines the accuracy of CNC machine tools. For the past few years, the domestic research on the linear grating sensor mainly concentrates in high precision grating motherboard manufacturing, long grating ruler manufacturing, absolute coding technology, single-field scanning technology, and so on. There is only a little research on the temperature character and mechanical structure. But temperature character and mechanical structure of grating sensor has great influence on its accuracy.This paper first analyses the factors affecting the accuracy of linear grating sensor, focus on the analysis of the errors introduced by the two factors of the temperature character and mechanical structure. And then carries out a scheme based on the temperature character and mechanical structure. We use steel as the material of the grating ruler, because its linear expansion coefficient is unified with the machine tools and the work. We choose the guide rail structure to achieve the relative motion of the reading head and the grating ruler. The reason that the structure used is that the guide rail movement is smooth,flexible and less of vibration. Finally, this paper designs the connection mode, appearance and the seal type.This paper carries out some experiments on assembly, debugging and signal processing. And the final results has passed the verification of China Institute of Metrology.