A Variable Stiffness Electroadhesive Gripper Based on Low Melting Point Alloys

Abstract

Electroadhesive grippers can be used to pick up a wide range of materials, and those with variable stiffness functionality can increase load capacity and strength. This paper proposes an electroadhesive gripper (VSEAF) with variable stiffness function and a simple construction based on low melting point alloys (LMPAs) with active form adaptation through pneumatic driving. Resistance wires provide active changing stiffness. For a case study, a three-fingered gripper was designed with three electroadhesive fingers of varied stiffness. It is envisaged that these electroadhesive grippers with variable stiffness would extend the preparation process and boost the use of electroadhesion in soft robot applications.

Design and Experiment Investigation on Soft Grippers with Modular Variable Stiffness Structure

“…Liu et al [ 3 ] proposed a shape-memory alloy (SMA)-based soft gripper with variable stiffness composed of three robotic fingers for grasping compliantly at low stiffness and holding robustly at high stiffness, where the paraffin as a variable stiffness material in the joint can be heated or cooled to change the stiffness of the robotic fingers. Xiang et al [ 4 ] designed an electro-adhesive gripper with variable stiffness and a simple construction based on low-melting-point alloys, where the active form adaptation and active changing stiffness can be achieved by pneumatic driving and resistance wires, respectively. Nishida et al [ 5 ] developed a robot gripper based on an electromagnet and a reforming magnetorheological (MR) fluid which is employed to adjust the gripper stiffness.…”

Synergizing Structural Stiffness Regulation with Compliance Contact Stiffness: Bioinspired Soft Stimuli‐Responsive Materials Design for Soft Machines

“…[13][14][15][16] Recently, researchers have presented several stimuli-response materials that can achieve mechanical responses under the action of external fields, [17][18][19][20] such as light, [21] magnetic, [22,23] and electric fields. [24] Utilizing this distinctive feature of advanced materials, such as dielectric elastomers (DEs), [25][26][27] low-melting-point alloys (LMPAs), [28][29][30] and shape memory polymers (SMPs) [31][32][33][34][35] to construct soft machines, can endow them with tunable structural stiffness. For instance, Aksoy et al employed DEs to develop multimorph soft actuator sheets with enhanced loadbearing capabilities, which could obtain multiple distinct configurations controlled by Joule heating.…”