Studying the Effect of the Tail on the Dynamics of a Flapping-Wing MAV using Free-Flight Data

Rijks, Frank G.; Karásek, Matěj; Armanini, Sophie F.; Visser, Coen C. de

doi:10.2514/6.2018-0524

Cited by 3 publications

(5 citation statements)

References 31 publications

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“…It is therefore useful for design purposes, and may help to explain the large differences observed between short and long tails of similar area or aspect ratio. 44 The effective cycle-averaged AOA behaves in a complementary way, first decreasing and then increasing. This is consistent with the variation in flapping-induced velocity: where there is less induced velocity, the AOA is closer to the AOA of the wings/ body and the contribution of the free stream becomes relatively more important compared to that of the flapping.…”

Section: Local Flow and Tail Force Predictionmentioning

confidence: 99%

“…On the one hand, flapping-wing vehicles are typically very small, so their tails generate very small forces that may be difficult to measure even with highly accurate force sensors. 44 This makes it particularly difficult to carry out measurements on the tail alone. On the other hand, clamping the full FWMAV in the wind tunnel results in vibrations, especially in z B direction, that are not observed in free flight 45 -a significant problem because this is the direction the tail is expected to contribute to most.…”

Section: Aerodynamic Coefficientsmentioning

confidence: 99%

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Modelling wing wake and tail aerodynamics of a flapping-wing micro aerial vehicle

Armanini

Caetano

Visser

et al. 2019

International Journal of Micro Air Vehicles

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Despite significant interest in tailless flapping-wing micro aerial vehicle designs, tailed configurations are often favoured, as they offer many benefits, such as static stability and a simpler control strategy, separating wing and tail control. However, the tail aerodynamics are highly complex due to the interaction between the unsteady wing wake and tail, which is generally not modelled explicitly. We propose an approach to model the flapping-wing wake and hence the tail aerodynamics of a tailed flapping-wing robot. First, the wake is modelled as a periodic function depending on wing flap phase and position with respect to the wings. The wake model is constructed out of six low-order sub-models representing the mean, amplitude and phase of the tangential and vertical velocity components. The parameters in each sub-model are estimated from stereo-particle image velocimetry measurements using an identification method based on multivariate simplex splines. The computed model represents the measured wake with high accuracy, is computationally manageable and is applicable to a range of different tail geometries. The wake model is then used within a quasi-steady aerodynamic model, and combined with the effect of free-stream velocity, to estimate the forces produced by the tail. The results provide a basis for further modelling, simulation and design work, and yield insight into the role of the tail and its interaction with the wing wake in flapping-wing vehicles. It was found that due to the effect of the wing wake, the velocity seen by the tail is of a similar magnitude as the free stream and that the tail is most effective at 50-70% of its span.

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Section: Local Flow and Tail Force Predictionmentioning

confidence: 99%

Section: Aerodynamic Coefficientsmentioning

confidence: 99%

Modelling wing wake and tail aerodynamics of a flapping-wing micro aerial vehicle

Armanini

Caetano

Visser

et al. 2019

International Journal of Micro Air Vehicles

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“…The measurement results were further used to estimate the flow conditions near the MAV tail (Section 3.2.1), which is of relevance for the flight performance in terms of control and stability. Although a full exposure of the design implications of these results is beyond the scope of the present paper, information on the flow conditions near the tail is expected to be supportive to the modeling of wake/tail interactions and the interpretation of "black-box" flight control data [21,22].…”

Section: Discussionmentioning

confidence: 86%

“…Although a further exposure of the design implications of these results is beyond the scope of the present paper, information on the flow conditions near the tail is expected to be supportive to the modeling of wing-wake/tail interactions [21], and to further interpret "black-box" data on tail surface sizing and tail effectiveness [22]. Figure 9.…”

Section: Estimation Of Flow Conditions Perceived By the Tailmentioning

confidence: 81%

Flow Visualization around a Flapping-Wing Micro Air Vehicle in Free Flight Using Large-Scale PIV

et al. 2018

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Flow visualizations have been performed on a free flying, flapping-wing micro air vehicle (MAV), using a large-scale particle image velocimetry (PIV) approach. The PIV method involves the use of helium-filled soap bubbles (HFSB) as tracer particles. HFSB scatter light with much higher intensity than regular seeding particles, comparable to that reflected off the flexible flapping wings. This enables flow field visualization to be achieved close to the flapping wings, in contrast to previous PIV experiments with regular seeding. Unlike previous tethered wind tunnel measurements, in which the vehicle is fixed relative to the measurement setup, the MAV is now flown through the measurement area. In this way, the experiment captures the flow field of the MAV in free flight, allowing the true nature of the flow representative of actual flight to be appreciated. Measurements were performed for two different orientations of the light sheet with respect to the flight direction. In the first configuration, the light sheet is parallel to the flight direction, and visualizes a streamwise plane that intersects the MAV wings at a specific spanwise position. In the second configuration, the illumination plane is normal to the flight direction, and visualizes the flow as the MAV passes through the light sheet.Aerospace 2018, 5, 99 2 of 15 Quite a variety of visualization PIV studies on animals in free flight have been reported, see e.g., [11][12][13]; however, the direct correspondence to the current MAV configuration is limited. Firstly, most of these studies consider single-wing configurations at relatively fast forward flight, for which the flow dynamics are less complex than for hovering or slow forward flight, especially in the case of counter-flapping wing configurations with large-amplitude and high-frequency stroke behavior, as considered here. Furthermore, flow visualizations reported in literature have predominantly been limited to wake visualizations, while near-wing visualizations suffer in large regions around the wing from reflections or the obstruction of the illumination [13].The MAV used in the current tests is the DelFly II (henceforth called DelFly for simplicity) [3], for which tethered experiments have been previously performed in hovering [14,15] and symmetric forward flight (at zero pitch angle) [9] configurations. These configurations both result in symmetrical flow patterns around the wings, which is not representative of true forward flight, where an appreciable forward velocity is combined with a high pitch angle. This will result in upper and lower wings experiencing distinctly different aerodynamic conditions. Tethered flow visualization experiments have been carried out on a different DelFly version at relatively small pitch angles [16], whereas [17] reports on preliminary results of a setup intend to enable free-flight wake visualization by controlling the MAV at a fixed position in the exit of a large wind tunnel. The current investigation takes a different and novel approach by aiming to visualiz...

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“…21 In almost all the works done for controlling pitch and yaw channels of flapping wings MAVs, they used the elevator and rudder in the same manner as in fixed-wing flying vehicles. 22,23 Also, valuable research about mechanism design, aerodynamics, and recent progress in the field of flapping wing MAVs are presented in Chellapurath et al, 24 Karimian and Jahanbin, 25 and Haider et al 26 DelFly MAV with one degree of freedom for the motor to produce thrust and with a rudder and elevator for guidance and control is famous. After reviewing the MAV's studies, we see the modeling and simulation of a dragonfly with an active rigid abdomen is important and fills the gap.…”

Section: Introductionmentioning

confidence: 99%

Hardware in the loop simulation and implementation of a dragonfly-like MAV using clap and fling mechanism

Lashgari

Naghash

2023

Proceedings of the Institution of Mechanical Engineers, Part C:

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The main aim of this paper is to model and simulate flight dynamics and to design a controller for a dragonfly-like micro aerial vehicle (MAV). This MAV has flapping wings using a clap and fling mechanism with a rigid abdomen. Kane’s method is applied to derive the longitudinal motion equations of the MAV as a multi-body system. Then, the aerodynamic lift and drag forces of the MAV are obtained. These equations are substituted in the derived motion equations. Furthermore, a new structure for a dragonfly-like flapping wing MAV is presented in which abdomen motion is considered in the longitudinal mode. In this work, the use of the abdomen is also formulated. A change in the motor’s speed generates differential thrust that creates a pitch moment as a control input. State space linearized equations of motion are presented by using appropriate assumptions in the aerodynamics, and dynamic nonlinear equations. To validate the linearized model, the response of the open-loop linear system is compared with the nonlinear one. In addition, the positive role of the abdomen in the open loop is discussed and analyzed. Finally, an LQR controller is designed for the pitch mode which is robust against disturbances. The validity, effectiveness, and performance of the derived equations and designed autopilot are shown by implemented hardware in the loop testbed using a fixed abdomen. Results demonstrate a good agreement between theoretical and experimental responses with accurate hovering at the desired angle.

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Studying the Effect of the Tail on the Dynamics of a Flapping-Wing MAV using Free-Flight Data

Cited by 3 publications

References 31 publications

Modelling wing wake and tail aerodynamics of a flapping-wing micro aerial vehicle

Modelling wing wake and tail aerodynamics of a flapping-wing micro aerial vehicle

Flow Visualization around a Flapping-Wing Micro Air Vehicle in Free Flight Using Large-Scale PIV

Hardware in the loop simulation and implementation of a dragonfly-like MAV using clap and fling mechanism

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