Online reprogramming electronic bits for <i>N</i> dimension fractal soft deformable structures

Inspired by the complex fractal morphologies and deformations observed in animals and plants, an <i>N</i>-dimensional soft structure composed of stretchable electronic bits has been developed. This soft structure, capable of independent and cooperative motion, can be manipulated through the programming of bits using a machine language based on instruction encoding. This method simplifies the process of changing the bit's step temperature to control its binary state. Theoretical analysis demonstrates that the fractal dimensions and deformation morphologies of the soft structure achieve stability and extremity when the total number of programming bits exceeds eighteen. Considering strip-shaped soft structures as a case study, their ultimate deformation morphologies, covering the reachable regions of all bits, can achieve complexity comparable to that of dandelion tufts and tree crowns. Moreover, the deformation process exhibits agility akin to that of an octopus. We have prepared samples that include strip-shaped soft structures, each containing multiple pairs of bits, and a hand-shaped soft structure equipped with five pairs of bits, intended for conducting deformation programming experiments. These experimental results validated the correctness of the online reprogramming method for soft structures, showing their capability to perform a range of complex deformations, such as the "OK" gesture, and highlighting potential applications in surgical contexts. This design strategy contributes to the development of soft structures, offering contributions from both theoretical and practical perspectives.