Sensorizing high-aspect-ratio soft robots: towards closed-loop applications for grasping and locomotion

High aspect ratios are a common feature in biological systems like muscle fibers, tentacles, or annelids that inspire novel applications in artificial muscles, grasping, manipulation, and locomotion. This paper explores interoceptive and exteroceptive sensing methods for high-aspect-ratio soft robots to overcome the limitation of externalized sensing and control, which is currently typical for such robots. We present a design and manufacturing process for sensorized soft robots (aspect ratio ∼17) with an integrated stretchable carbon microparticle proprioception sensor and phototransistor-based exteroceptive layer for low-resolution ambient light detection. We show that our interoceptive sensor provides accurate results for curling during 120 pressurization cycles. The exteroceptive sensor detects the proximity of other robots but shows only a slight correlation during entanglement tests. Finally, we demonstrate that sensorized high-aspect-ratio soft robots can detect the disentanglement of robots under load.