An Experimental Platform for Understanding Size Scaling of Latch-Mediated Spring Actuation

Latch-mediated spring actuation (LaMSA) systems use elastic elements to produce extremely strong strikes, high jumps, and other fast movements that outperform direct motor actuation at small size scales. The size-scaling of LaMSA system performance has been mathematically modeled, but not physically modeled. This work presents development and validation of a LaMSA mechanism for understanding scaling of latch-mediated spring actuation. The mechanism consists of a five-bar linkage with an elastic element running across it. Using commercially available components and common fabrication techniques, we create multiple versions of the mechanism isometrically scaled by almost an order of magnitude in size. Using high speed videography to measure the unloading kinematics, we find the mechanism's maximum velocity and acceleration, as well as the kinetic energy released. We compare these results with mathematical modeling to validate the correct scaling of the mechanism, demonstrating its utility as an experimental platform for understanding scaling of LaMSA systems. Finally, we present explorations of other scaling regimes, such as measuring performance across scales with increasing payload mass, and non-isometrically scaling the elastomer.