Design and Fabrication of Bistable Actuators With High Load Capacity Based on Origami

Soft pneumatic actuators are a crucial component of soft robotics, typically fabricated using elastic materials. Multistability plays a significant role in the future engineering applications of robotics; hence, the feature of multiple stable states is considered, including in pneumatic structures. Here, we propose a bistable structure based on origami principles, capable of switching between two stable states: folded and unfolded. This bistable structure, combined with Kresling pneumatic chambers, has led to the development of two types of programmable torsional actuator structures—torsional extension and torsional bending. The torsion angle, direction, extension height, and bending angle can be programmed through the design parameters of the actuators. These bistable actuators exhibit high axial stiffness in stable state, with the load capacity of the torsional extension and torsional bending actuators exceeding their own weight by 1470 times and 1240 times, respectively. Based on these two actuators, multistable switches, soft grippers, and an arch bridge have been reconfigured to perform various tasks. The bistable actuator is expected to break through limitations in load conditions and manufacturing costs. Its autonomous unfolding and locking characteristics ensure a more robust structure postdeployment, offering new insights into building expandable, sturdy systems.