Design and feasibility tests of a flexible gripper based on inflatable rubber pockets

In this paper, we present feasibility test results of a flexible gripper design following a literature survey on various types, design and control strategies of the existing grippers. A flexible gripper based on the use of compliant materials (i.e., rubber) with pneumatic inflation was designed, analyzed, built and tested. Parametric FE analyses were conducted to investigate the effects of process and design parameters, such as rubber material, pressure, initial jaw displacement and friction. Based on the FEA results, a simple, single rubber-pocketed flexible gripper was designed and built. Feasibility experiments were performed to demonstrate and obtain an overall understanding about the capability and limitations of the gripper. It was found that objects with different shapes (cylindrical, prismatic and complex), weight (50 g–20 kg.), and types (egg, steel hemi-spheres, wax cylinders, etc.) could be picked and placed without any loss of control of the object. The range of positioning error for two different part shapes (i.e., prismatic or cylindrical) was found to be 20–90 μm (translational) and 0.03–0.9° (rotational).