Flexible Printed Circuit Board Strain Sensor Embedded in a Miniaturized Pneumatic Finger

A miniaturized pneumatic finger allows for safer grasping without damaging the surface of an object. A flexible strain sensor was developed and embedded in a miniaturized pneumatic finger to sense the finger’s self-deformation as a feedback control signal. The proposed flexible strain sensor comprised a Zr-based metallic glass sensing material and a flexible printed circuit board (FPCB) substrate. The properties of fabricated strain sensors with different patterns and with metallic glass thin films of different thicknesses were measured. The miniaturized pneumatic finger was fabricated from a highly elastic polymer by demolding. To integrate the flexible strain sensor and the miniaturized pneumatic finger, surface treatment was performed to improve the bonding strength. Measurements of the contact angle and peel-off force reveal that the treated surfaces have lower contact angles and higher bonding strength. This higher bonding strength between the flexible strain sensor and the miniaturized pneumatic finger prevented the destruction of the finger during bending. The developed flexible strain sensor embedded in the miniaturized pneumatic finger could sense the finger’s self-deformation by measuring changes in resistance.