A biomimetic sensor for a crawling minirobot

This paper presents the development of a biomimetic sensor, with the ability to imitate exteroceptor and proprioceptor functions of invertebrates, such as earthworms. 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. Perforated PVDF strips are embedded in a segmented silicone shell of a crawling earthworm minirobot with the ability to elongate and contract, thanks to a smart configuration of shape memory alloy actuators. A 4-segment minirobot with a sensorised skin has been fabricated. Experiments on separate sensorised silicone segments and also on the sensorised minirobot show that the biomimetic PVDF-based sensors can detect both the external contact and the internal actions, thus imitating the exteroceptive and proprioceptive sensing capabilities of real earthworms.