Soft Kirigami Actuators

Electrothermal bimorph actuators are widely used in soft robotics and MEMS devices due to their simplistic design and ease of controllability. While a wide range of studies have investigated one-dimensional tip-bending actuators and used them to develop grippers, robots, and optical devices, actuation in more complex geometries with multiple degrees of freedom is yet to be examined. In this study, we propose and investigate more intricate motions using electrothermal bimorph actuators to manipulate thin sheets. We demonstrate out-of-plane bulging actuators embedded in continuous thin films that can achieve vertical displacement exceeding 2cm from the rest position. We explore the motion numerically and experimentally and examine new emerging regimes of actuation. By strategically inducing curvatures with actuators on sheets with cuts, we show deformations resembling buckling modes of kirigamis. Unlike buckling modes generated by stretching, the use of electrical actuation enables local and independent actuation of these kirigami-like deformations. Our work sets a foundation for the design of more complex soft structures.