  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. We propose a
novel concept of single-input control of an actuator composed of interconnected
bi-stable elements. Dynamic response of the actuator and pre-designed
differences between the elements are exploited to facilitate any desired
multi-state transition, using a single dynamic input. We show formulation and
analysis of the control system's dynamics and pre-design of its multiple
equilibrium states, as well as their stability. Then we fabricate and
demonstrate experimentally on single-input control of two- and four-element
actuators, where the latter can achieve transitions between up to 48 desired
states. Our work paves the way for next-generation soft robotic actuators with
minimal actuation and maximal dexterity.
