Integrative Studies of Escape Flight in Hummingbirds: From Perception and Aerodynamics to Maneuverability

Hummingbirds are nature~s masters of agile aerodynamic maneuvers, they have arguably the bestperforming visual-perception among all natural fliers and are the most adept at capitalizing upon unsteady, high-force aerodynamic mechanisms for maneuverability. The proposed research aims to reveal how hummingbirds produce complex escape maneuvers, which is arguably the ultimate natural behavior amenable to laboratory tests for understanding how the maneuverability arises from the interactions among perceptual, musculoskeletal and aerodynamic processes, and therefore for making genuine advancement in the understanding and translation of biologicalautonomy.This research will start from quantifying the maneuverability of calliope hummingbirds while they escape to different directions, which will be compared with those measured in other two species of hummingbirds (black-chinned and magnificent) and insect fliers (hoverfly, bumblebee and hawkmoth), as well as with a hummingbird-sized quadrotor flier. The optimality of the observedhummingbird escape maneuvering patterns will be assessed by solving optimal control problems based on dynamic models with imposed kinematic and energetic constraints. Through the comparative study, we will identify the specific ways hummingbirds exceed other natural or manmade fliers, and reveal the underlying limiting factors of maneuverability. Next, we will quantify,on the functional level, how the visual and auditory perceptual cues drive the elicitation, modulation and stabilization of the escape maneuvers in terms of their patterns, magnitude and timings. The potential causal inference capability of hummingbirds will also be investigated. In addition, we will also investigate how hummingbirds combine perception with spatial memory of obstacles arranged in the flight arena in the production of escape maneuvers. Next, the forcevectoring and unsteady aerodynamic mechanisms exploited by the hummingbirds in the escape maneuvers will be studied using a combined experimental and computational-fluid-dynamics (CFD) methods. The CFD results will enable us to study the required muscle mechanical powerfor the hummingbird escape maneuvers, from which to determine whether they are energetically possible for the quadcopter. Finally, we will study the musculoskeletal responses in terms of both muscle activation/deactivation and the skeletal movements in the escape maneuver, which is an integral part for maneuverability. We will record the neuromuscular recruitment of the pectoralismuscle during escape maneuvers using electromyography (EMG) experiments and study the timing of activations and deactivations change in response to varied perceptual cues arrived at different stages of escape maneuvers. In addition, we will use high-speed 3D fluoroscopy X-ray of Moving Morphology (XROMM) to measure skeletal movements during the escape maneuvers.Together this research seeks to develop an informed-translation of biological perception-and control principles to autonomous systems for agile locomotion. The knowledge gained will have broad impacts on both aerial and underwater systems that are designed to achieve high agility in fluid environments by solving perception and locomotion control problems. In addition, thisproject will also enable a multi-disciplinary collaborative team to integrate principles in animal behavior and perception, dynamic modeling, unsteady aerodynamics, optimal control and neuroscience for STEM education activities that foster interdisciplinary learning experiences for a diverse group of students.