Co-Programming Shape Morphing and Interaction Forces of Soft Grippers for Compliant Grasping

The shape-morphing capability and interaction forces of soft grippers are pivotal in determining the grasping performance, particularly in tasks that require gentle and safe handling, such as the manipulation of fragile or delicate objects. However, most soft gripper designs primarily focus on enhancing the deformation range and load capacity at the fingertip, often neglecting precise regulation of deformation and interaction forces during contact with objects. In this article, a novel topology-optimization framework for soft gripper design is proposed, aiming to achieve large-area contact with specified objects and uniformly distributed interaction forces. The grasped object is modeled by a set of springs, and the optimization objective concurrently regulates the gripper's shape morphing and the contact forces in terms of their distribution and resultant force. The gradient-based optimization algorithm generates a soft adaptive gripper design with interpretable structural features. Quantitative experiments demonstrate that the optimized gripper satisfies the specified requirements, exhibiting uniform wrapping over a large area and sufficient grasping force biased toward the palm side as desired to counteract gravity. Grasping tests with various objects, ranging from small cherry tomatoes to a 1.55 L bottle of water, further highlight the gripper's superior compliance, adaptability, and load capacity.