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

A control method of electromagnetic feedback is proposed for adjusting frequency response characteristics of fiber optic accelerometers, which could expand the flat working bandwidth and enhance performance consistency. The proof sensor employs an open-loop disc-type vibration pickup structure, cascaded with an electromagnetic feedback control unit. A proportional-differential control algorithm is utilized to generate the feedback signal, which ultimately acts on the input side of the sensor. Experimental results show that the 3 dB bandwidth of the constructed closed-loop system is expanded to approximately 210 Hz, more than 3.5 times that of the open-loop system, while maintaining a sensitivity of 72.97 dB re rad/g. Furthermore, the regulated closed-loop systems exhibit a significantly reduced response deviation, compared to the open-loop systems with fluctuating response characteristics due to fabrication errors.