Position Estimation for Ultra-Low Speed Gimbal Servo System of SGMSCMG Based on Linear Hall Sensors

In the low speed servo system of single gimbal magnetically suspended control moment gyro (SGMSCMG), the accuracy of rotor position is an important factor which influences the speed accuracy. Linear hall sensors with small volume and high precision are usually adopted to the compact equipment and suitable for SGMSCMG. However, the signals detected by hall sensors contain lots of harmonics and noise which influence the accuracy significantly. For this reason, a novel precise position detection method based on 2-step cascaded Kalman filter with phase compensation scheme is proposed to extract the precise position information from 'dirty' signals. The proposed method is advantageous since it is very simple and practical, and the phase compensation scheme can primely compensate the phase delay caused by cascaded Kalman filter. Finally, the experiments are carried out in a 50Nm SGMSCMG, and the results show that the method can effectively estimate the angular position of the ultra-low speed servo motor, and the position accuracy can be improved by 85.7%.