PVDF-based Biomimetic Sensor for Application in Crawling Soft-body Mini-Robots

This paper focus on developing a flexible biomimetic sensor, which is embedded in a soft earthworm-like crawling mini-robot and mimics exteroceptive and proprioceptive functions of invertebrates, such as its biological counterpart-earthworm. A polyvinylidene fluoride (PVDF) film is selected as the sensing element because it is flexible, highly sensitive and easy to be integrated in different shapes. Thin and narrow PVDF strips are embedded with an innovative molding-embedding-remolding fabrication procedure in a segmented compliant silicone shell which serves as skin and passive actuation of a crawling earthworm-like mini-robot with the ability to elongate and contract. Several experiments were performed by using a purposely developed test-bench in order to test sensor behaviour. The results show that the biomimetic flexible PVDF-based sensor can detect both the external contact and the internal actions, thus imitating the exteroceptive and proprioceptive sensing capabilities of real earthworms. The developed biomimetic sensors are promising in order to achieve an useful sensor feedback for the earthworm-like minirobot motion control