Design of Multifunctional Soft Doming Actuator for Soft Machines

Bilayer bending based soft actuators are widely utilized in soft robotics for locomotion and object gripping. However, studies on soft actuators based on bilayer doming remain largely unexplored despite the often-observed dome-like shapes in undersea animals such as jellyfish and octopus suction cup. Here, based on the simplified model of bending-induced doming of circular bilayer plates with mismatched deformation, we explore the design of soft doming actuator upon pneumatic actuation and its implications in design of multifunctional soft machines. The bilayer actuator is composed of patterned embedded pneumatic channel on top for radial expansion and a solid elastomeric layer on bottom for strain-limiting. We show that both the cavity volume and bending angle at the rim of the actuated dome can be controlled by tuning the height gradient of the pneumatic channel along the radial direction. We demonstrate its potential multifunctional applications in swimming, adhesion, and gripping, including high efficient jellyfish-inspired underwater soft robots with locomotion speed of 84 cm/min and rotation-based soft grippers with low energy cost by harnessing the large rim bending angle, as well as octopus-inspired soft adhesion actuators with strong and switchable adhesion force of over 10 N by utilizing the large cavity volume.