小型绝对式光电轴角编码器电路优化设计

为实现绝对式光电轴角编码器的小型化和智能化，设计了一种基于DSP2812和数字电位计的小型绝对式光电编码器处理电路。提出采用全数字化处理的方法实现粗、精码信号的处理；利用DSP内部A/D转换器实现粗码信号的放大、整形等功能，取消人工调试机械电位器及放大器、比较器等硬件；同时，将编码器精码信号幅值偏差、稳定性偏差的实时补偿算法嵌入到处理电路中。以16位编码器为实验对象，测试电路性能。实验表明，新设计的处理电路的直径仅为36 mm，且光电信号幅值变化率≤2%，直流漂移量≤2%，实时补偿时间约为2 s。其性能可靠，实现编码器机电一体式，缩小了航天设备的体积，且有效提高了编码器的环境适应性和测角可靠性。

Optimal circuit design for miniature absolute photoelectric encoder

In order to realize the miniaturization and intelligence of absolute photoelectric encoder, a processing circuit based on DSP2812 and digital potentiometer was designed. To automatically adjust the amplitude of precise and coarse signal, a fully digital processing method was proposed. The DSP with A/D was used to achieve amplification and shaping of coarse code signal. And several hardware such as debugging mechanical potentiometer, amplifier and comparator were cancelled. Meanwhile, real time compensation algorithm for amplitude deviation and stability deviation of precise code signal was embedded into the processing circuit. To test the capability of the processing circuit, a 16-bit encoder was selected as the experimental object. The experimental results showed that the diameter of the newly designed processing circuit was merely 36 mm. The amplitude variation rate of photoelectric signal was less than 2%. The DC drift value was less than 2%. Real-time compensation time was about 2s. The new processing circuit with electromechanical integration was reliable, which can minimize the size of aerospace equipments, and improve the environmental adaptability and angle measurement reliability of the encoder.