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In the past decade, a rich repertoire of soft robots, designed from biomimetic and intuitive approaches, has been developed to overcome challenges faced by their rigid-bodied counterparts. However, these design approaches are greatly limited by the designers' experience and inspiration. In this article, the structural design problem is mathematically modeled under the framework of topology optimization, and solved by a new implementation tool that combines Abaqus/CAE and Matlab coding. Herein, a pneumatic soft gripper with two identical fingers was developed as a practical application. To fulfill the grasping task, each gripper finger is optimized to achieve its maximal bending deformation. The optimized gripper fingers are in high consistence with human fingers as indicated by pseudo-joints. Thereafter, the optimized gripper fingers are directly fabricated by three-dimensional printing technique with unprecedented fidelity regardless of high geometric complexity. Experimental results show that the gripper can grasp an elastic balloon, and each gripper finger is able to undergo a [Formula: see text] free travel bending and exert 0.23 N grasping force upon 0.06 MPa actuation pressure. The proposed approach is freely extendable to develop other types of soft robots and this represents an important step toward the goal of designing and fabricating soft robots automatically.

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Kirigami is the art of paper cutting, and it is emerging as an elegant design and manufacturing solution in mechanical metamaterials. Currently, the majority of kirigami designs focus on shape-morphing, but there is little attention on the remarkable mechanical properties they can produce: high strength to weight ratio where they can bear thousands of times of their own weight. This paper proposes a kirigami-based, strong, yet lightweight metamaterial, which is created by folding pop-up and pop-down from a checkerboard pattern with blocks. To transform the kirigami metamaterial into arbitrary objects, the challenge lies in how to automatically design the kirigami folding to approximate the outline of the object. Herein, a computational model that is based on deploying discretized objects onto a planar sheet is proposed. Additionally, to achieve high strength, a glue-free connector that can lock the collocated cuts in the folded configuration is designed. The standard compression tests show that the kirigami metamaterial, weighing 12.05 g, can carry 346.4 N payloads. Meanwhile, six examples of curved surfaces are prototyped to verify the shape transforming capability of the proposed kirigami metamaterial. This study paves the way towards using the kirigami technique for weight reduction in industrial applications.