A Passive Dynamic Approach for Flapping-Wing Micro-Aerial Vehicle Control

Abstract

This article outlines a new control approach for flapping-wing micro-aerial vehicles (MAVs), inspired both by biological systems and by the need for lightweight actuation and control solutions. In our approach, the aerodynamic forces required for agile motions are achieved indirectly, by modifying passive impedance properties that couple motion of the power stroke to the angle of attack (AoA) of the wing. This strategy is theoretically appealing because it can exploit an invariant, cyclical power stroke, for efficiency, and because an impedance-adjusting strategy should also require lower bandwidth, weight, and power than direct, intra-wingbeat control of AoA. We examine the theoretical range of control torques and forces that can be achieved using this method and conclude that it is a plausible method of control. Our results demonstrate the potential of a passive dynamic design and control approach in reducing mechanical complexity, weight and power consumption of an MAV while achieving the aerodynamic forces required for the types of high-fidelity maneuvers that drive current interest in autonomous, flapping-wing robotics. NOMENCLATURE c(r) Chord length of wing, at radius r c m (r) Mean chord position, at radius r COP Center of pressure on wing during flappinḡ c w Normalized mean chord length ω w Flapping frequency (rad/s)

The Dynamics of Passive Wing-Pitching in Hovering Flight of Flapping Micro Air Vehicles Using Three-Dimensional Aerodynamic Simulations

“…The results for these two wing planforms are consistent with the parametric study in Ref. 21. Further parametric studies on the relationship between wing planform and aerodynamic performance can serve as a basis for wing shape and hinge stiffness selection.…”

“…Here, we use the overset grid method. Notice that the technical literature describes the implementation of a significant number of simulations based on quasi-steady blade-element formulations and on Navier-Stokes solvers, with diverse degrees of fidelity, in order to study the lift mechanisms and the aerodynamic forces generated by flapping wings with fully prescribed kinematics 21,22,23,24 . However, to this date, the use of integrated (rigid dynamics + CFD) simulations aiming to understand the complex dynamical behavior of wings that simultaneously actively flap and passively pitch has not been sufficiently investigated.…”

A Review of Biomimetic Air Vehicle Research: 1984-2014

“…One example that has been investigated involves first passively coupling the wing's feathering DOF to the active controlled flapping DOF, then varying the wing joint's stiffness using a tunable impedance system. The feathering DOF is semi-actively controlled by adjusting the impedance without any effect on the flapping DOF (Byl, 2010 [44]).…”

Kinematic and Aerodynamic Modelling of Bi- and Quad-Wing Flapping Wing Micro-Air-Vehicle

“…A generic semi-elliptical ornithopter's wing planform with the backdrop of various wing-planform geometries[9] [15]-[20].Blade element theory has been utilized for flapping wing analysis by many researchers[2] [7][16] [28]. In the present work, unsteady aerodynamics of a flapping wing using a modified strip theory approach as a simplification of DeLaurier's and Harmon's approach for pterosaur flapping-wing aerodynamics is carried out without post-stall behavior.…”

“…In the present work, unsteady aerodynamics of a flapping wing using a modified strip theory approach as a simplification of DeLaurier's and Harmon's approach for pterosaur flapping-wing aerodynamics is carried out without post-stall behavior. Byl[16] and Malik and Ahmad[29] have applied blade element and De-Laurier's approach in their work, respectively. A novel initiative has been introduced by Djojodihardjo and Ramli [19] [20] for separating the wing flapping motion element and carrying out a parametric study on the contribution of each of these elements in the aerodynamic forces generated.…”