Finite-state mechanologic for embodied control in soft machines

Soft machines have attracted interest for their ability to interact with their environment and adapt to external disturbances. However, their nonlinear material behavior can be challenging, often necessitating complex sensing and feedback systems. To overcome these limitations, it is essential to develop material and structural designs that embody control in the system. Multistable structures offer a potential solution, enabling programmable, discrete shape changes via specific actuation sequences without the need for closed-loop control. This study explores a class of pneumatically actuated morphing systems that encode multiple accessible, stable states, offering a route to shape reconfiguration and embodied intelligence by combining soft robotics with dome-patterned metastructures. Informed by the mechanics of hierarchically multistable metastructures, we design coexisting states that resemble distinct actuation modes in soft machines. Notably, the mechanical response of our morphing metastructures can be abstracted as a finite state automaton, a mathematical model used to depict and emulate sequential logic. We demonstrate how to describe our soft structures system as a temporal finite state machine that yields different output shapes depending on the recorded sequence. Our strategy offers a new approach to controlling soft robots by exploiting the nonlinear mechanics of multistable structures to the designer’s advantage, thereby paving the way for embodied finite-state technology in soft structures.