Longitudinal Actuated Abdomen Control for Energy Efficient Flight of Insects

Abstract

The actuated abdomens of insects such as dragonflies have long been suggested to play a role in optimisation and control of flight. We have examined the effect of this type of actuation in the simplified case of a small fixed wing aircraft to determine whether energetic advantages exist in normal flight when compared to the cost of actuation using aerodynamic control surfaces. We explore the benefits the abdomen/tail might provide to balance level flight against trim changes. We also consider the transient advantage of using alternative longitudinal control effectors in a pull up flight maneuver. Results show that the articulated abdomen significantly reduces energy consumption and increase performance in isolated manoeuvres. The results also indicate a design feature that could be incorporated into small unmanned aircraft under particular circumstances. We aim to highlight behaviours that would increase flight efficiency to inform designers of micro aerial vehicles and to aid the analysis of insect flight behaviour and energetics.

Biomimetic Drones Inspired by Dragonflies Will Require a Systems Based Approach and Insights from Biology

“…Generally, in manned fighter aerial combat, the aircraft with the ability to maintain a higher specific energy and excess power has a greater maneuver advantage [76]. We have reported [71] an average of 1% more specific energy and 1.83% more excess power using abdominal deflection to initiate a steady pull up maneuver, in comparison with using the elevator. In most small electrically powered aircraft, at least 50% of the power available is used for propulsion [77].…”

“…Although hover is important for a dragonfly, it is not their primary mode of flight, as they spend most of their flight time in forward motion [69]. There has been little effort to quantify these effects [70] and little attempt, until recently, to consider the effects of these posture changes on flight performance [71]. The following analysis considers the potential roles of abdominal articulation in an abstracted fixed wing glider at constant speed.…”

“…The non-linear equations of motion for a fixed wing aircraft are adapted here to include an abdomen/tail modelled as an added mass, m T , concentrated at the tip of a massless rod [71]. For the purposes of isolating inertial forces from aerodynamic forces on the tail, the aerodynamic effects of the tail were ignored, as these effects are expected to have little influence on the aerodynamics of the aircraft, compared to the wings, legs, and thorax.…”

“…The translational and rotational dynamic equations are represented by Equations ( 3) and (4), respectively [71,72]:…”

“…The "yaw" turn, which is the second turning mode, is achieved without banking; rather, the longitudinal axis of the dragonfly turns, which has now been modelled and simulated, as shown in Figure 11. Energy savings have been recorded to achieve longitudinal balance and pull up maneuvers by manipulating moments using abdominal articulation as alternative control effectors to conventional aerosurfaces [71]. Overall, a 4-5% average in propulsive power savings was recorded using abdominal movements for the correction of comparatively mild imbalances in steady cruise.…”