Ultra-tunable bistable structures for universal robotic applications

Bistable structures in nature are unparalleled for their fast response and force amplification even with the most minute physical stimulation. However, current works on bistable structures mainly focus on their stable states, while promising intermediate states with a large range of tunable energy barriers are missing. Here, we report a type of ultra-tunable bistable structure. Our results show that the trigger force of a single structure can be tuned to 0.1% of its maximum value, and the lifted weight difference exceeds 107 times using grippers composed of proposed structures with different design parameters. We prototyped various functional robots using the proposed structures to demonstrate their wide-range design space across materials and scales, such as an ultra-sensitive robotic flytrap, a fast catcher, a minimal jumper, etc. This work broadens the frontiers of bistable structure design and leads a way to future design in robotics, biomedical engineering, architecture, and kinetic art.