An Autonomous Snapper with Physical Intelligence

Harnessing elastic instabilities enables plants to surpass the constraints of their intrinsically slow and limited movement. Carnivorous plant D. muscipula, for example, can control the spatial variation of osmotic pressure on its leaves to induce snap-through transition and to reset their curvature for subsequent predatory snaps. Nature‘s use of elastic instability has profoundly influenced the development of many snap-through systems in the soft robotics field. However, majority of these systems cannot perform autonomously under uniform stimulation due to the energy barrier between two states. In our paper, we present a novel strategy to achieve autonomous snapping under uniform stimulation by exploiting the interaction between the snapping device with its environment. We illustrate that the mechanism is rooted in the photothermally induced snap-through and energy transfer of the snapper with the environment, regulated by a negative feedback loop enabling autonomous snapping. We investigate the underlying mechanism through experiments and numerical simulations. The snapper’s interaction with its environment facilitates sustained and adaptive motion, attributing physical intelligence to the device and allowing it to function as both an actuator and a sensor. Our findings reveal the snapper’s capability to differentiate substrates based on color and texture, leading to its application as a color detector. We finally explore the snapper’s ability to adapt to changes in the stimulation and the environment. These results demonstrate an effective approach for developing autonomous and physically intelligent actuators.