High-dynamic tracking control technology for the fast-steering mirror in a laser communication system

Area of Science:

• Optics and Photonics
• Control Systems Engineering
• Aerospace Engineering

Background:

• Laser communication systems demand high-precision tracking to maintain beam stability.
• Fast-steering mirrors (FSMs) are critical components for achieving this precision.
• Existing control strategies often face challenges with parameter tuning and system accuracy.

Purpose of the Study:

• To design an active disturbance rejection control (ADRC) strategy for FSMs.
• To improve tracking accuracy and bandwidth while simplifying parameter tuning.
• To address system delays and enhance both overshoot suppression and rapid response.

Main Methods:

• Development of a reduced-order extended state observer-based ADRC strategy.
• Introduction of a differential adjustment factor to manage tracking differentiator delays.
• Implementation and experimental validation of the reduced-order linear active disturbance rejection control (RLADRC) algorithm.

Main Results:

• RLADRC achieved an 8.49% and 17.99% reduction in rise time compared to PID and LADRC, respectively, for a 1 mrad step response.
• RLADRC showed 24% and 21% lower amplitude attenuation than PID and LADRC under a 300 Hz sinusoidal input.
• Superior tracking performance and reduced phase lag were observed with RLADRC.

Conclusions:

• The RLADRC strategy significantly enhances FSM tracking performance in terms of speed and accuracy.
• The proposed method offers improved disturbance rejection and simpler parameter tuning.
• RLADRC meets the stringent requirements for practical engineering applications, such as 30 Hz frame-rate imaging systems.