A 3D printed flexible electroadhesion gripper

A gripper is a robot end effector that performs the grasping function. Primarily, stiff and soft conventional grippers are differentiated. Compared to typical rigid grippers, soft grippers provide more flexibility, the ability to grasp complicated curved surfaces, and the capacity to move delicate objects; nevertheless, their preparation technique is challenging and their fabrication is laborious. With the evolution of multi-material 3D printing technology, multi-material 3D printers are able to manufacture an endless number of material combinations with a simple preparation technique and high precision, and are widely used in the medical equipment, aerospace, and other sectors. This study shows a totally 3D-printed flexible gripper consisting of a flexible electroadhesion (EA) pad, a bio-inspired spiral spring, and an EA fixture in an attempt to solve the limitations of current methods for producing flexible electrodes and soft grippers. For the production of flexible EA pads, two kinds of conductive and non-conductive polylactic acid (PLA) materials are utilized; polylactic acid and thermoplastic polyurethanes (TPU) materials are used for the production of an EA fixture and an adaptable gripper. The breakdown voltage, shear and normal EA forces of flexible EA pads were evaluated, as well as the optimal size configuration was determined. The breakdown voltage, shear force, and normal EA force of the flexible EA pad were evaluated, and the optimal size configuration was determined. The optimal size configuration is rectangular comb electrode 1, with an electrode width of 4 mm, electrode spacing of 4 mm, and a duty cycle of 0.50. Under the optimal size configuration, the breakdown voltage, shear force, and normal EA force are 4.8KV, 1.192 +/- 0.006 N, and 0.049 N, respectively; a fixture based on biomimetic spiral springs and TPU fingers was designed and manufactured, and employed as a fixture for flexible EA pads. A novel type of bubble artificial muscle actuator was employed as the driving device for the flexible fixture; finally, the fixture gripped a 215.2 g object (130 mm x 60 mm x 95 mm) in the combined action of EA force and mechanical clamping force. It is hoped that these flexible grippers would broaden the usage of preparation technology and electroadhesion in soft robots.

Automated summary

This study presents a fully 3D-printed flexible gripper that utilizes electroadhesion technology and mechanical clamping force for object grasping. The gripper is made from multiple materials and the optimal size configuration is determined. It is expected that these flexible grippers can be widely applied in soft robots.