An additional velocity loop in the CCD and MEMS accelerometer-based lightweight optoelectronic system control

Abstract

In the charge-coupled device(CCD)-based optoelectronic system(OS)，the external disturbance has a bad influence on the line-of-sight(LOS) stabilization, especially in a moving platform. Generally, with a high-performance fiber-optic gyroscope(FOG), we build a velocity inner loop to enhance the disturbance suppression ability(DSA). However, FOG has a big size, high cost and power consumption which limit its application in space-constrained occasion. With the development of the micro-electro-mechanical system(MEMS) industry, the MEMS accelerometer and gyro are more used in the optoelectronic field for their small volume and low price. Since the MEMS accelerometer has a much higher bandwidth than the MEMS gyro, it’s more suitable to build a high-bandwidth and high-sampling inner loop to enhance the DSA. Unfortunately, since the signal of the MEMS accelerometer in low frequency is weak and commonly with drift and much noise, the low-frequency DSA of the inner loop is insufficient. Considering the CCD has a good low-frequency signal and the MEMS accelerometer has an advantage in high frequency, based on the acceleration and position double-loop control(APDC), we proposed to add an additional velocity loop by fusing the CCD’s low-frequency signal and the accelerometer’s high-frequency signal with an open-loop bandwidth fusion method(OBF) to further enhance the DSA. The fusion velocity even has a higher bandwidth than the MEMS gyro. A series of comparative experimental results demonstrate the proposed method could get a lightweight OS with a strong DSA, which is close to the triple loop control based on the MEMS accelerometer and real gyro, and even has a better DSA in medium frequency.