Plant-inspired Mechano-sensing Soft Robot

Modern society relies on robotic automation to accomplish menial, hazardous, and sophisticated tasks. A growing subfield of robotics uses soft materials to accomplish these tasks. While promising, soft robots typically lack a key feature: mechanosensitivity. To address this challenge, we designed a smart skin transmitting information using non-linear poroelasticity in a fashion reminiscent of plant mechanoperception. More specifically, we used a biocompatible strain-softening material, Ecoflex©, to design a skin perforated with channels filled with a liquid that we implemented on a homemade 3D-printed arm and connected to a pressure sensor. When the robot arm grasps an object, the skin deformation leads to a superlinear increase in pressure, enabling accurate stress measurements. We could then experimentally access the strain applied by the robotic arm and use these inputs in combination with contact mechanics theory to extract the radius and effective Young's modulus of the grabbed object. Furthermore, the versatile nature of the Ecoflex© sensitive skin enables its implementation on surgical devices to measure the mechanical properties of cancerous and healthy tissues, thus complementing biopsies. As such, this innovative skin broadens horizons for automation, robotic surgery, and ensures safer interactions between robotic devices and humans.