Gecko-Inspired Adhesive Grasping from Convex to Flat Surfaces with Contact Sensing

This article introduces a gecko-inspired, rolling, inward adhesion/outward release gripper with adhesive contact sensing for grasping convex-to-flat surfaces. The gripper consists of pneumatically driven hierarchical adhesive modules (bio-toe) with the capability of contact sensing, and rolling inward/outward module (rolling module). The bio-toe manufactured using soft materials can safely and flexibly cater to curved and flat surfaces. The rolling module developed using four-bar linkage mechanism allows the opposing bio-toes to roll inward to enhance adhesion (adhesion forces up to 6.3 N on a flat surface and 23 N on an 18 m-1 curved surface) and roll outward to decrease the force in releasing (less than 3 N and especially less than 0.8 N on the flat surface). Embedded resistive strain gauges provide real time signals for the controller to determine the status of the bio-toe, such as bending, adhesion/release, and even adhesive contact rates, thereby allowing the gripper to autonomously approach, envelop, adhere to, and release objects of various shapes, with the potential for dynamic adhesion control in the future. The adhesive gripper equipped with adhesive contact sensing and biomimetic inward adhesion/outward release capabilities exhibits a broader grasping range and applicability in smart adhesive grabbing across industrial, agricultural, and human-robot interaction contexts.