Topology Optimization and Prototype of a Highly Adaptive Multi-Material Compliant Finger for Parallel Grippers

Developing an adaptive robotic finger or gripping jaw capable of handling objects of diverse sizes and shapes presents a significant challenge in robotics. The fin ray-type compliant finger is one of the designs intended to adapt to the contours of a workpiece using passive compliance of its structure. However, according to our tests, the fin ray-type fingers only conform well to circular objects. In order to develop a highly adaptive finger design suitable for parallel grippers, we present a multi-material and multi-objective topology optimization method to synthesize an innovative compliant finger capable of conforming to circular, rectangular, concave, and asymmetric objects. The prototype of the multi-material compliant finger is manufactured via 3D printing using two different elastomers, and two identical fingers are installed on a parallel gripper actuator for grasping applications. The gripper's adaptability is determined based on the total contact length between its fingers and the object being grasped. The experimental results show that our novel multi-material parallel gripper outperformed the fin ray-type compliant gripper in both adaptability and maximum payload.