Online Error Compensation of Gyroscope in MWD Based on MGMA

To solve the problem of low accuracy of the microelectromechanical system (MEMS) gyroscope output in measurement while drilling (MWD), an online error compensation method for MEMS gyroscope based on magnetic-gravitational mayfly algorithm (MGMA) is proposed in this article. First, the source of the MEMS gyroscope error is analyzed and the error compensation model is established. Then, using the feature that the accelerometer has no cumulative error to design objective function, and the constraint conditions of the angle of gravity vector are designed by using anti-vibration magnetometer. Furthermore, on the basis of mayfly algorithm (MA), the upper and lower bounds are determined adaptively according to the relationship between the output of the gyroscope and magnetometer, aiming at the constantly changing gyroscope error parameters caused by the harsh environment in the drilling process. The relative error of gravitational modulus is used to design the inertia weight and balance the exploration and exploitation of the algorithm. Finally, according to the relative error of the magnetic-gravitational modulus, a mutation disturbance strategy is introduced in the offsprings to reduce the possibility of falling into the local optimal. The experimental results show that the gyroscope error after MGMA compensation is obviously decreased, the error of the inclination is reduced from 9.88° to 1.67°, and compared with particle swarm optimization (PSO) and MA algorithm, it has faster speed and higher accuracy.