Meeting Abstract
Small insects repeatedly jump with high take-off velocities by storing elastic energy in springs from deformation of the exoskeleton. These jumps allow insects to navigate rough terrain, clearing obstacles many times their own size, making them sources of inspiration in microrobots. However, at-scale microrobots lack the agility of insects, in part due to limited understanding of energy storage in the exoskeleton of insects. Insect springs are often composites of stiff chitin and compliant resilin, with a difference in Young’s Modulus over three orders of magnitude. The resilin contributes very little to the springs’ stored elastic energy, so its role is unclear. To explore the role of ‘soft’ materials in springs, the insect spring was simplified to a synthetic analog, a bilayer cantilever beam. We explored the dynamic and failure properties of the springs both experimentally and theoretically. Dynamic properties of the spring did not vary significantly with varying thickness of soft material, but ultimate stored elastic energy did; springs with thicker soft material stored more energy through increased deflection. However, mass-specific stored energy in composite springs decreased, though the mass of insect springs is negligible compared to body mass. Theoretical exploration shows a stark contrast in the design sensitivity of stored potential energy to material thickness. Potential energy storage is less sensitive to soft material thickness in composite springs than the thickness of single material springs, so any mistakes in soft material thickness are negligible compared to mistakes in hard material; this facilitates designing a greater reliability in jumping robots while sacrificing little performance, a key trait for the success of autonomous robots.
