Multistable Structures for Embedded Energy Storage

In traditional robotic systems, batteries are fixed-volume components, limited to a singular function and requiring dedicated space and weight. Exploring new strategies involves distributing energy storage across system components, drawing inspiration from biological systems where energy reserves are seamlessly integrated into the overall system, similar to blood circulation in living organisms. One promising approach is the use of metafluids, enabling embedded energy storage resembling an energetic vascular system, or ‘robotic blood’. These metafluids are composed of multistable building blocks sealed with gas, with magnets attached to their ends. By aligning these components with integrated electromagnetic actuators, induced motion or thermal changes can facilitate charging, enabling extensive long-term energy storage in local minima energy configurations. Moreover, energy can be harvested during rapid magnet transition in the vicinity of coils during snap-through events between stable states of the structures.<br/><br/>In this work, we investigate both theoretically and experimentally the equilibrium states of externally actuated multistable structures, identifying regions where nonlinear electromagnetic actuation allows for energy charging and discharging. Furthermore, we examine the transient non-equilibrium states of these structures under external electromagnetic and thermal actuation. Our findings highlight the critical role of balancing the effects of sealed gas and the structure’s elasticity for achieving efficient energy storage and release cycles, while considering the harvesting of induced energy during transitions between stable states. Additionally, our simulations capture the multi-timescale dynamics of the structure and its stored energy, identifying thermodynamic processes across cycling stages through a general thermodynamic analysis, free from imposed assumptions on these processes. These insights suggest a promising pathway for advancing embedded energy technologies using metafluids, offering a potential advancement beyond conventional robotic energy storage solutions.