Chordwise wing flexibility may passively stabilize hovering insects

Area of Science:

• Bio-inspired robotics
• Insect flight dynamics
• Fluid-structure interaction

Background:

• Insect wings are flexible, influencing aerodynamics and power.
• Previous studies on insect flight dynamics often assume rigid wings.
• Rigid wings are typically associated with unstable hover equilibrium due to pitch sensitivity.

Purpose of the Study:

• To investigate the influence of wing flexibility on insect flight dynamics.
• To determine if wing flexibility contributes to stable hover equilibrium in insects.
• To provide insights for designing stable flapping wing robots.

Main Methods:

• Simulated free-flight insect dynamics at the fruit fly scale in the longitudinal plane.
• Modeled chordwise wing flexibility using a linear beam.
• Solved two-dimensional Navier-Stokes equations within a fluid-structure integration scheme.

Main Results:

• Demonstrated that flapping wing flyers with flexible wings exhibit stable hover equilibria.
• Showed that for insect-like wing flexibilities, all system matrix eigenvalues have negative real parts.
• Identified that flexible wings stabilize unstable modes by passively deforming, increasing horizontal velocity and pitch rate damping.

Conclusions:

• Insect wing flexibility plays a crucial role in passively stabilizing hover flight.
• The passive stabilization mechanism via wing deformation enhances damping of perturbations.
• Findings can inform the design of more stable and efficient synthetic flapping wing robots.