Optical Fiber Sensor Performance Evaluation in Soft Polyimide Film with Different Thickness Ratios

Area of Science:

• Materials Science
• Robotics Engineering
• Optical Sensing

Background:

• Soft biomedical robotics and flexible morphing wings require precise curvature measurement.
• Optical Fiber Bragg Grating (FBG) sensors offer potential for shape monitoring.
• Limited analysis of FBG sensor embedding depth in polyimide film restricts application.

Purpose of the Study:

• Investigate the relationship between FBG sensor embedded depth in polyimide film and its sensitivity and stability.
• Optimize FBG sensor design for soft robotics and morphing wing applications.
• Validate the performance of embedded FBG sensors for curvature measurement.

Main Methods:

• Introduced the sensing principle and structural design of the FBG sensor embedded in polyimide film.
• Studied the bending curvatures of the FBG sensor and its wavelength shift within the polyimide film.
• Experimentally verified the relationship between sensor sensitivity, stability, and embedded depth.

Main Results:

• Established a linear relationship between wavelength shift and curvature.
• Achieved sensitivities ranging from 1.96 pm/m⁻¹ to 50.65 pm/m⁻¹ for curvatures up to 30 m⁻¹.
• Demonstrated good consistency and stability in repeated experiments for soft actuator and morphing wing measurements.

Conclusions:

• The developed FBG sensor embedded in polyimide film exhibits reliable performance for shape monitoring.
• The embedded depth significantly influences FBG sensor sensitivity and stability.
• This FBG sensing method shows strong potential for real-world applications in soft robotics and flexible morphing wings.