Meeting Abstract
5-2 Saturday, Jan. 4 08:15 - 08:30 Resonance Properties of Insect-Inspired Series-Elastic Flapping Wings LYNCH, J*; GAU, JF; SPONBERG, S; GRAVISH, N; University of California, San Diego; Georgia Institute of Technology; Georgia Institute of Technology; University of California, San Diego jelynch@ucsd.edu
Flying insects are thought to achieve energy-efficient flapping flight by storing and releasing elastic energy in their muscles, tendons, and thorax. The dynamics and energy efficiency of this process depend on the insect anatomy and the aerodynamic forces experienced by the wing. However, despite significant investigation into the aerodynamics of flapping wings, the influence of elasticity and wing inertia on the dynamics and control of wing movements is relatively unexplored. We developed a dynamically-scaled robophysical experiment to study the resonance properties of flapping wing aerodynamics in the regime of insect flight (Reynolds number between 102 – 104). We observed the steady-state behavior of an acrylic wing actuated in series with a cast silicone torsion spring, varying the elastic element stiffness over a 4-fold range, system inertia over a 3-fold range, flapping amplitude (10 – 64 deg), and frequency (0.5 – 4.1 Hz). Comparing our results to a simplified analytical model of the system with quasi-steady drag forces, we found that the model fits the observed resonance behavior within ± 10% at steady state, suggesting that unsteady aerodynamic phenomena have a weak influence on the steady state dynamics of flapping wings with elastic elements. These experiments indicate the importance of wing inertia, body elasticity, and muscle actuation dynamics towards minimizing energy expenditure in flapping wing flight and aerodynamic force control in insects.