Combining a Disturbance Observer with Triple-Loop Control Based on MEMS Accelerometers for Line-of-Sight...

Area of Science:

• Optical Engineering
• Control Systems
• Sensor Technology

Background:

• Traditional line-of-sight (LOS) stabilization in fine tracking optical systems (FTOS) relies on fiber-optic gyroscopes (FOGs).
• FOGs present challenges due to high cost, large size, and limited space in compact systems.
• Micro-electro-mechanical system (MEMS) accelerometers offer a cheaper, smaller alternative but suffer from low-frequency noise susceptibility, limiting disturbance suppression ability (DSA).

Purpose of the Study:

• To develop a cost-effective and compact inner loop for FTOS stabilization using MEMS accelerometers.
• To overcome the limitations of MEMS accelerometers in low-frequency disturbance suppression.
• To enhance the overall disturbance suppression ability (DSA) of CCD-based FTOS.

Main Methods:

• Proposed a novel approach combining a disturbance observer (DOB) with triple-loop control (TLC) for MEMS accelerometer-based inner loop.
• Implemented a composite velocity loop through acceleration integration, corrected by CCD.
• Utilized DOB to improve medium-frequency DSA and adjusted the composite velocity loop for enhanced low-frequency DSA.

Main Results:

• The proposed method significantly improves medium-frequency DSA via the DOB.
• The composite velocity loop effectively enhances low-frequency DSA, compensating for accelerometer limitations.
• Experimental verification confirms superior DSA compared to traditional methods.

Conclusions:

• The combined DOB and TLC approach effectively utilizes MEMS accelerometers for FTOS stabilization.
• This method offers a viable, cost-effective alternative to FOGs for LOS stabilization.
• The system demonstrates improved disturbance suppression ability across various frequencies.