Energy-Efficient 3D-Printed Multi-Material Gripper with Integrated Smart Sensing and Actuation

Soft grippers, while ideal for handling delicate and irregular objects, often require continuous input to maintain grip, limiting energy efficiency. This paper presents a naturally closed, energy-efficient soft gripper with integrated sensing and actuation. The gripper's body is fabricated in a single step and incorporates a conductive thermoplastic polyurethanes (TPU) layer for proprioception and external sensing. A novel 3D-printed Acrylonitrile Butadiene Styrene (ABS) curved flat spring enhances grasp force and enables rapid closure when actuated by a shape memory alloy (SMA). A multi-objective optimization study is performed which offers guidelines for balancing print efficiency and dimensional accuracy in TPU 3D printing by tuning layer height and print speed. Finite Element Analysis (FEA) is also carried out to further evaluate the gripper's deformation behavior. The gripper was successfully deployed on a humanoid robot to perform pick-and-place tasks, demonstrating its practical functionality.