全数字IMU方案研究

分析了现有IMU内部模拟电路的不足，提出全数字IMU方案和结构框图，其内容包括高精度模数转换电路、高速数学运算平台、陀螺数字伺服电路、高精度数字温控电路和以数字滤波数据融合为核心的计算方法。论证了陀螺回路数字控制方案、陀螺模糊温度控制方案，确定出陀螺回路A／D采样频率应大于3000Hz，高精度A／D转换器采样频率应大于500Hz，且位数不应低于18bit。最后，展示了已经研制成功的3项试验结果：24bit A／D与陀螺和加速度计联机实测结果、CPU和24bit A／D间接口通讯逻辑接口和基于模糊控制的陀螺温控系统。

Full-digital IMU Scheme

The defects of the analog circuits in inertial measurement unit were analyzed at first, and the full-digital inertial measurement unit scheme was presented, including high precise A/D, high-speed calculation unit, digital servo-loop for gyro, high precise digital temperature control circuit and the algorithm of digital filter and data fusion. Then the precepts of digital servo-loop for gyro and fuzzy temperature control circuits were discussed. The sampling frequency of digital servo-loop for gyro and high precise A/D that measured the output of gyros were estimated as more than 3000 Hz and 500 Hz. Finally, the results of three parts of the scheme were presented. The first is the testing datum of 24bit A/D that is connected with gyro and accelerometer. The second is logic-interface between CPU and 24bit A/D. And the last one is gyro temperature control based on fuzzy control.