Adjusting frequency response characteristics of fiber optic accelerometers using electromagnetic feedback technology

Area of Science:

• Instrumentation and Measurement
• Optical Sensors
• Control Systems Engineering

Background:

• Fiber optic accelerometers are crucial for measuring acceleration.
• Existing designs often have limited flat working bandwidth and performance consistency issues.
• Electromagnetic feedback offers a potential solution to these limitations.

Purpose of the Study:

• To propose and validate a control method using electromagnetic feedback for fiber optic accelerometers.
• To enhance the frequency response characteristics, specifically expanding the flat working bandwidth.
• To improve the overall performance consistency and reduce response deviation.

Main Methods:

• A disc-type vibration pickup structure was employed in an open-loop configuration.
• An electromagnetic feedback control unit was cascaded with the sensor.
• A proportional-differential (PID) control algorithm was used to generate the feedback signal.
• The feedback signal was applied to the sensor's input.

Main Results:

• The closed-loop system achieved a 3 dB bandwidth of approximately 210 Hz, a 3.5-fold increase over the open-loop system.
• Sensitivity was maintained at 72.97 dB re rad/g.
• The closed-loop system demonstrated significantly reduced response deviation compared to the open-loop system.
• Improved performance consistency was observed, mitigating issues caused by fabrication errors.

Conclusions:

• Electromagnetic feedback control effectively expands the flat working bandwidth of fiber optic accelerometers.
• This control strategy enhances performance consistency and reduces measurement deviations.
• The proposed method offers a viable approach for improving accelerometer performance in demanding applications.