Dynamic Single-Input Control of Multistate Multitransition Soft Robotic Actuator

Soft robotics is an attractive and rapidly emerging field, in which actuation is coupled with the elastic response of the robot's structure to achieve complex deformation patterns. A crucial challenge is the need for multiple control inputs, which adds significant complication to the system. A novel concept of single-input control of an actuator is proposed, which composes of interconnected bistable elements. Dynamic response of the actuator and predesigned differences between the elements are exploited to facilitate any desired multistate transition using a single dynamic input. Formulation and analysis of the control system's dynamics and pre-design of its multiple equilibrium states, as well as their stability, are shown. Then, fabrication and demonstration are done experimentally on single-input control of two- and four-element actuators, where the latter can achieve transitions between up to 48 desired states. This work paves the way for next-generation soft robotic actuators with minimal actuation and maximal dexterity.