High resolution interpolation techniques of small photoelectric encoder

In order to improve the resolution and interpolation precision of the small photoelectric encoder without increment of size and weight, some research has been carried out on the high-resolution interpolation method. Firstly, main factors which affected the resolution and interpolation precision of the small photoelectric encoder were analyzed, and then the analog-to-digital conversion gain error and imbalance error were calibrated by microcontroller of ADuC841. Finally, the electronic interpolation algorithm was optimized, and a small photoelectric encoder signal processing circuit with high interpolation precision was designed. Experimental results showed that precise code signal interpolation of 1 024 parts of the encoder could be realized with this design, and peak-to-peak value of the interpolation cycle error could be reduced from 163 to 70. The resolution of the small photoelectric encoder with an exterior diameter of 40 mm could be improved by 4 times up to 4.98, and its precision could be improved to 30. The method improves the resolution and interpolation precision of the encoder.Because of its simple circuit structure and high resolution interpolation the method could be applied to absolute and incremental photoelectric encoders with the limitation of size and weight.