Research On Diffraction Photoelectric Angle Displacement Sensor

With the continuous advancement of science and technology,photoelectric angular displacement sensors are widely used in various high-precision equipment due to their high precision,compact structure,and high stability.They are considered to be the sensors with the most market potential.However,such sensors are seldom applied on scanning galvanometer.At present,most of the angle sensors used on the scanning galvanometer on the market are potentiometers,encoders and so on,which limits the measurement method and the size of the structure integration.In order to solve the above problems,this paper designs a diffractive photoelectric angular displacement sensor for measuring the rotation angle of the scanning galvanometer,which uses the method of reflecting the circular grating to produce diffraction light interference to measure the rotation angle of the galvanometer with high precision.At the same time,in order to ensure the measurement accuracy,the reflector in the angle sensor and the scanning galvanometer are designed to be coaxial,so as to realize the measurement of the ±10° rotation angle of the scanning galvanometer,and the measurement accuracy can reach 10".In addition,the reflection of the reflective circular grating and the reflecting mirror can be matched with the folding prism to realize the light reentry,making the overall structure compact and small,with a small moment of inertia,meeting the high-precision and miniaturization requirements of the scanning galvanometer.It promotes the application of photoelectric angular displacement sensor in scanning galvanometer.In this paper,the design of diffractive photoelectric angular displacement sensor is completed in three aspects.The first is the selection of the method and the establishment of the model.Based on the principle of diffraction and interference,this paper gives the design scheme of the diffraction photoelectric angular displacement sensor and establishes the corresponding mathematical model.Using the ±1st-order diffracted light interference generated by the reflective circular grating,with a mirror designed coaxially with the scanning galvanometer,the angle information is converted into the variation of the interference fringe,and the rotation angle of the galvanometer is obtained.The mathematical model is established according to the measurement scheme.The change of light path is given according to the direction of the optical path.The specific relationship between the angle of scanning galvanometer and the intensity of interference fringe is deduced.The model is simulated and analyzed,and the measurement optical path is given by the quantitative model.The second is the overall structure design.According to the established mathematical model,the mechanical structure and signal processing circuit of the diffractive photoelectric angular displacement sensor are designed,including the fixing of various components,the photoelectric conversion module,the amplifying circuit,the comparison shaping circuit,the serial output circuit and software design of signal processing circuit.The last is experimental measurement and analysis.According to the measurement plan,the design of the diffraction photoelectric angular displacement sensor is completed,and the scanning galvanometer lens and driver designed by the cooperative company are used to complete the design of the scanning galvanometer prototype using the diffraction photoelectric angular displacement sensor.Specific experiments are carried out by building a detection platform,and the accuracy detection of the diffraction photoelectric angular displacement sensor is completed with the help of a high-precision turntable,photoelectric autocollimator and so on,and the error is analyzed.