基于重力四元数的陀螺漂移估计与补偿

为提高钻探中的钻具姿态测量精度,提出一种基于重力四元数的MEMS惯性随钻姿态测量方法.采用MEMS惯性器件构建钻具姿态测量系统,把加速度计数据解算的姿态四元数作为观测四元数,陀螺仪数据解算的姿态四元数作为误差四元数;然后将陀螺仪漂移融入误差四元数,建立重力四元数估计陀螺仪误差四元数的模型,采用最小二乘法估计陀螺仪三轴漂移,进而补偿陀螺仪姿态四元数;通过补偿后的姿态四元数解算出钻具姿态.最后设计了转台、振动台实验和钻进模拟实验,实验结果表明,姿态四元数补偿后的井斜角和工具面角漂移由平均10 °/h减小到约0.2 °/h,方位角误差由平均12 °/h减小到约0.46 °/h,实现了加速度计补偿陀螺的三轴漂移,表明该方法能够有效提高钻具的姿态测量精度.

Gyro drift estimation and compensation based on gravity quaternion

In order to decrease the attitude measurement error while drilling,an gravity quaternion estimating triaxial gyro drift-based(AQEGD)attitude measurement algorithm is proposed using an inertial sensor composed of a triaxial accelerometer and a triaxial gyroscope.The gravity quaternion based on accelerometer data is regarded as an observation vector,the gyro quaternion based on gyro data as an error vector blended in triaxial gyro drift;The triaxial gyro drift errors are sensed by the gravity quaternion using the linear least square estimation algorithm,by which the gyro quaternion used to calculate drilling tools dynamic attitude orientation is compensated;At last turntable experiment,shaking-table experiment and drilling experiment are conducted to verify the performance of the proposed algorithm in various dynamic condition settings and to provide further insight into the variations in the estimation accuracy.Furthermore,the experiments indicate that the proposed AQEGD can lower the triaxial gyro drift,with corresponding orientation average errors of deviation angle and tool face angle from 10 °/h(before compensation)to 0.2 °/h(after compensation),azimuth from 12 °/h to 0.46 °/h.