Neuromuscular control of aerodynamic forces and moments in the blowfly, Calliphora vicina

Flapping insect flight is a complex and beautiful phenomenon that relies on fast, active control mechanisms to counter aerodynamic instability. To directly investigate how freely flying Drosophila melanogaster control their body pitch angle against such instability, we perturbed them using impulsive mechanical torques and filmed their corrective maneuvers with high-speed video. Combining experimental observations and numerical simulation, we found that flies correct for pitch deflections of up to 40 deg in 29±8 ms by bilaterally modulating their wings' front-most stroke angle in a manner well described by a linear proportional-integral (PI) controller. Flies initiate this corrective process only 10±2 ms after the perturbation onset, indicating that pitch stabilization involves a fast reflex response. Remarkably, flies can also correct for very largeamplitude pitch perturbations -greater than 150 deg -providing a regime in which to probe the limits of the linear-response framework. Together with previous studies regarding yaw and roll control, our results on pitch show that flies' stabilization of each of these body angles is consistent with PI control.

Section: Physiological Basis For Pitch Controlmentioning

confidence: 61%

Pitch perfect: how fruit flies control their body pitch angle

Whitehead

Beatus

Canale

et al. 2015

“…Nachtigall reported similar kinematic alterations for the fly Phormia regina during tethered flight (Nachtigall, 1966). Mean stroke frequency in tethered C. vicina varies between 127 and 180Hz (mean 158Hz) (Nachtigall and Roth, 1983) and between 120 and 160Hz (Balint and Dickinson, 2004), whereas slightly smaller values were found by Ennos for this species when flying freely (117 to 158Hz) (Ennos, 1989). We confirmed these values by scoring stroke frequency within the first nine to 29 stroke cycles during unrestrained take-off behaviour, using a high-speed camera (Phantom V12, Vision Research, Wayne, NJ, USA).…”

Section: Wing Kinematicsmentioning

confidence: 84%

Elastic deformation and energy loss of flapping fly wings

Lehmann

Gorb

Nasir

et al. 2011

SUMMARY During flight, the wings of many insects undergo considerable shape changes in spanwise and chordwise directions. We determined the origin of spanwise wing deformation by combining measurements on segmental wing stiffness of the blowfly Calliphora vicina in the ventral and dorsal directions with numerical modelling of instantaneous aerodynamic and inertial forces within the stroke cycle using a two-dimensional unsteady blade elementary approach. We completed this approach by an experimental study on the wing's rotational axis during stroke reversal. The wing's local flexural stiffness ranges from 30 to 40 nN m2 near the root, whereas the distal wing parts are highly compliant (0.6 to 2.2 nN m2). Local bending moments during wing flapping peak near the wing root at the beginning of each half stroke due to both aerodynamic and inertial forces, producing a maximum wing tip deflection of up to 46 deg. Blowfly wings store up to 2.30 μJ elastic potential energy that converts into a mean wing deformation power of 27.3 μW. This value equates to approximately 5.9 and 2.3% of the inertial and aerodynamic power requirements for flight in this animal, respectively. Wing elasticity measurements suggest that approximately 20% or 0.46 μJ of elastic potential energy cannot be recovered within each half stroke. Local strain energy increases from tip to root, matching the distribution of the wing's elastic protein resilin, whereas local strain energy density varies little in the spanwise direction. This study demonstrates a source of mechanical energy loss in fly flight owing to spanwise wing bending at the stroke reversals, even in cases in which aerodynamic power exceeds inertial power. Despite lower stiffness estimates, our findings are widely consistent with previous stiffness measurements on insect wings but highlight the relationship between local flexural stiffness, wing deformation power and energy expenditure in flapping insect wings.

“…As bilateral activation timing differences in these muscles are correlated with mechanical power output (Josephson, 1985), asymmetric flapping kinematics (e.g. Balint and Dickinson, 2004) and yaw torque production (Sponberg and Daniel, 2010), we can assess the magnitude of the hawkmoth's turning input by acquiring neuromuscular activation data from bilateral pairs of flight muscles.…”

Section: Introductionmentioning

confidence: 99%

Neuromuscular control of free-flight yaw turns in the hawkmothManduca sexta

Springthorpe

Fernández

Hedrick

2012

SUMMARYThe biomechanical properties of an animalʼs locomotor structures profoundly influence the relationship between neuromuscular inputs and body movements. In particular, passive stability properties are of interest as they may offer a non-neural mechanism for simplifying control of locomotion. Here, we hypothesized that a passive stability property of animal flight, flapping countertorque (FCT), allows hawkmoths to control planar yaw turns in a damping-dominated framework that makes rotational velocity directly proportional to neuromuscular activity. This contrasts with a more familiar inertia-dominated framework where acceleration is proportional to force and neuromuscular activity. To test our hypothesis, we collected flight muscle activation timing, yaw velocity and acceleration data from freely flying hawkmoths engaged in planar yaw turns. Statistical models built from these data then allowed us to infer the degree to which the moths inhabit either damping-or inertia-dominated control domains. Contrary to our hypothesis, a combined model corresponding to inertia-dominated control of yaw but including substantial damping effects best linked the neuromuscular and kinematic data. This result shows the importance of including passive stability properties in neuromechanical models of flight control and reveals possible trade-offs between manoeuvrability and stability derived from damping. Supplementary material available online at