title: Bumblebees minimize control challenges by combining active and passive modes in unsteady winds.
abstract: The natural wind environment that volant insects encounter is unsteady and highly complex, posing significant flight-control and stability challenges. It is critical to understand the strategies insects employ to safely navigate in natural environments. We combined experiments on free flying bumblebees with high-fidelity numerical simulations and lower-order modeling to identify the mechanics that mediate insect flight in unsteady winds. We trained bumblebees to fly upwind towards an artificial flower in a wind tunnel under steady wind and in a von Kármán street formed in the wake of a cylinder. Analysis revealed that at lower frequencies in both steady and unsteady winds the bees mediated lateral movement with body roll - typical casting motion. Numerical simulations of a bumblebee in similar conditions permitted the separation of the passive and active components of the flight trajectories. Consequently, we derived simple mathematical models that describe these two motion components. Comparison between the free-flying live and modeled bees revealed a novel mechanism that enables bees to passively ride out high-frequency perturbations while performing active maneuvers at lower frequencies. The capacity of maintaining stability by combining passive and active modes at different timescales provides a viable means for animals and machines to tackle the challenges posed by complex airflows.
authors.affiliation: Graduate School of Engineering, Chiba University, Japan.|School of Aerospace Mechanical and Manufacturing Engineering, RMIT University, Melbourne Australia.
authors.forename: Sridhar
authors.initials: S
authors.lastname: Ravi
authors.affiliation: Graduate School of Engineering, Chiba University, Japan.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Kolomenskiy
authors.affiliation: ISTA, Technische Universität Berlin, Müller-Breslau-Strasse 12, 10623 Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Engels
authors.affiliation: I2M - UMR 7373 - CNRS, Centre de Mathématiques et d'Informatique, Aix-Marseille Université, France.
authors.forename: Kai
authors.initials: K
authors.lastname: Schneider
authors.affiliation: School of Mechanical and Manufacturing Engineering, University of New South Wales, New South Wales, Australia.
authors.forename: Chun
authors.initials: C
authors.lastname: Wang
authors.affiliation: ISTA, Technische Universität Berlin, Müller-Breslau-Strasse 12, 10623 Berlin, Germany.
authors.forename: Jörn
authors.initials: J
authors.lastname: Sesterhenn
authors.affiliation: Graduate School of Engineering, Chiba University, Japan.|Shanghai-Jiao Tong University and Chiba University International Cooperative Research Centre (SJTU-CU ICRC), Shanghai, People's Republic of China.
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
mesh_terms: D000392:Air Movements; D000818:Animals; D001516:Bees / Q000502:physiology*; D001696:Biomechanical Phenomena; D005426:Flight, Animal; D008962:Models, Theoretical; D000072458:Orientation, Spatial; D014919:Wind