The Key Technology Of High Precision Micro Absolute Photoelectric Encoder

Absolute photoelectric encoder is by converting the optical signal into an electrical signal and output absolute position sensor information. Compared with the incremental photoelectric encoder output data with corresponding only after a position, needs no absolute zero, power-off restart also do not need to look for zero, no cumulative error,etc. Absolute encoder is widely used in robotics, CNC machine tools, radar, theodolite and other automation field. In the military and aerospace requirements such as high precision, small space, measurement range of more than360degrees, the single ring absolute photoelectric encoder can’t meet the requirements, needs multi-turn encoder to replace.Based on analyzing the working principle and composition of absolute photoelectric encoder on traditional, it uses a matrix-encoded code disc, and completed the code disc of16bit absolute photoelectric encoder, reduced the volume of the high number of encoder. It expounds the constraints of the relationship between the high-precision encoder and the dimension accuracy. Code disc and slit plate material uses K9glass, it has good light transmission, and it can also improve the accuracy of the photoelectric encoder. Meanwhile, the system gives the most suitable slit width of the slit plate. Due to the composition and structure of mechanical multi-turn encoder is very complex, there are many factors affecting the accuracy, it can’t ensure the accuracy of the encoder. It uses the combination of incremental and absolute encoder, ultimately, it achieves the function of the multi-turn absolute photoelectric encoder. Considering the accuracy and the number of bits in the absolute encoder, it uses the fine subdivision of the moire fringes tangent method.The papers around the key technology of micro high-precision absolute photoelectric encoder is designed miniature high-precision encoder system based on C8051F310MCU. It implements the hardware design of the optical system, signal processing system and data transmission system. And it also write the software of the signal processing, decoding, data transmission and tangent subdivision. Finally, it gives the physical figure and the experimental results of the system, and carries on the thorough analysis of the results.