Design of a Soft Pneumatic Actuator Finger with Self-strain Sensing

Benefit from high compliance, lightweight and natural motion, soft pneumatic actuators (SPAs) have shown great potential for using as fingers in robotic hands. Currently designed SPAs lack strain feedback, which limits their further applications. Soft fingers using SPAs require sensors embedded in their bodies for strain feedback, and most of the reported sensors used in SPAs are commercial products which suffer from low compliance, bulky volume and integration complexity. This work reports a SPA finger with self-strain sensing by integrating a SPA and a dielectric elastomer (DE) film capacitive strain sensor. The single-chamber with fiber reinforced SPA is chosen for bending motion. The DE film capacitive strain sensor is designed with a simple sandwiched structure which is easy-to-fabricate and thick enough for high compliance. The materials chosen to fabricate the SPA and the sensor are the same which helps to make the integration natural and closely bonded. The actuation response as well as sensing outputs are experimentally analyzed and results show that the sensing output change linearly with bending angles, which can be used for further position feedback control.