Optimal Design of a Highly Self-Adaptive Gripper with Multi-Phalange Compliant Fingers for Grasping Irregularly Shaped Objects

The development of a robotic gripper for handling objects of various sizes, shapes, weights, and degrees of hardness is a challenging problem in the field of robotics. In order to design a highly self-adaptive gripper capable of conforming to a wide range of objects, this article presents an innovative topology-optimized design of a compliant finger consisting of several multi-material phalanges connected by flexure hinges. The prototype was pro- duced by means of a metamaterial approach, which utilizes 3D- printed infill structures (periodic cells) with different infill densities to represent regions with different equivalent mechanical proper- ties. Adaptability tests were conducted to demonstrate the effec- tiveness of the proposed design in grasping circular, rectangular, trapezoidal, and concave objects. The results were compared with those of the fingers with single infill densities and a commercially available Festo MultiChoiceGripper, which features a Fin Ray structure. The total contact length between the fingers and the grasped object was used as a measure of the grippers’ adaptability. The test results demonstrate that this novel self-adaptive gripper is comparatively highly adaptable for grasping irregularly shaped objects and is able to carry a maximum payload of 6.76 kg.