Design of reprogrammable soft pneumatic actuators via physically cut-induced variable constraints

To address the design challenges of reprogrammable soft pneumatic actuators, we propose a cut-induced design strategy inspired by kirigami art. The actuator’s deformation capability is enabled by the expansion of internal cuts. Meanwhile, external cuts dynamically modulate the constraint patterns that the surrounding material exerts on expansion-driven deformation. Through the synergistic effect of internal and external cuts, the design of reprogrammable soft pneumatic actuators is realized. Leveraging this approach, a single structural body can achieve diverse deformation modes simply by creating or restoring external cuts through cut-and-bond process. Crucially, these diverse deformation modes are achieved using a single air source and a monomaterial actuator. It is maximally simplifies the architecture of reprogrammable soft pneumatic actuators. We further carried out experimental and simulation-based investigations to characterize the deformation behaviors of the elongation and bending elements. We established a dataset encompassing cut parameters, air pressure, and corresponding deformation outputs via finite element simulation. Building on this dataset, we constructed an inverse design method by integrating a backpropagation neural network with the NSGA-II multi-objective optimization algorithm. The letters U, V, J, and C were selected as target shapes. Our inverse design algorithm successfully reproduced these target shapes using a single soft actuator. Furthermore, leveraging this design strategy, we fabricated a soft gripper. Through reprogramming, this gripper achieved three typical grasping patterns found in human daily life. This not only demonstrates the significant advantages of our reprogrammable design approach, but also represents a notable advancement in research on reprogrammable pneumatic soft actuators.