A resonance suppression method in platform style inertial reference unit via particle swarm optimization notch filter

Area of Science:

• Mechanical Engineering
• Control Systems Engineering
• Optical Engineering

Background:

• Inertial reference units (IRUs) are crucial for line-of-sight (LOS) stabilization in applications like laser communication and remote sensing.
• Platform style IRUs (PIRUs) offer higher bandwidth and precision than frame style IRUs but suffer from mechanical resonance due to flexure hinges.
• This resonance negatively impacts the performance of LOS stabilization systems.

Purpose of the Study:

• To model and identify the mechanical resonance in a PIRU.
• To develop and optimize a method for suppressing this resonance to enhance system performance.
• To achieve a higher control bandwidth for the LOS stabilization system.

Main Methods:

• An open-loop dynamic model of the PIRU was established.
• Identification experiments were conducted to quantify resonance peaks (28.7 dB at 27.07 Hz on the x-axis, 30.3 dB at 26.59 Hz on the y-axis).
• An asymmetric notch filter was designed and optimized using a particle swarm optimization algorithm with a custom fitness function to suppress resonance.

Main Results:

• The asymmetric notch filter effectively suppressed the identified mechanical resonance peaks.
• Resonance peaks were reduced by 97.88%.
• The system's control bandwidth was significantly increased, reaching 159.31 Hz.

Conclusions:

• The developed method successfully mitigates mechanical resonance in PIRUs.
• Optimized asymmetric notch filters enhance the precision and bandwidth of LOS stabilization systems.
• This approach enables more accurate target acquisition, pointing, and tracking under external disturbances.