Active Control of the Hinge of a Flapping Wing with Electrostatic Sticking to Modify the Passive Pitching Motion

Peters, H.J.; Qi, Wang; Goosen, J.F.L.; Keulen, Fred van

doi:10.1007/978-3-319-44507-6_8

Cited by 3 publications

(4 citation statements)

References 19 publications

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“…The functioning of the first promising method (i.e., interaction of stacked layers) has been recently demonstrated both analytically and experimentally [14]. With this method, the bending stiffness of an elastic hinge consisting of stacked layers is changed by modifying the interaction between these layers (i.e., the layers stick or slip with respect to each other).…”

Section: Methods To Induce Structural Property Changesmentioning

confidence: 99%

Methods to actively modify the dynamic response of cm-scale FWMAV designs

Peters

Goosen

Keulen

2016

Smart Mater. Struct.

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Abstract. Lightweight vibrating structures (such as Flapping Wing Micro Air Vehicle (FWMAV) designs) often require some form of control. To achieve controllability, local structural property changes (e.g., damping and stiffness changes) might be induced in an active manner. The stroke-averaged lift force production of a FWMAV wing can be modified by changing the structural properties of that wing at carefully selected places (e.g., changing the properties of the elastic hinge at the wing root as studied in this work). To actively change the structural properties, we investigate three different methods which are based on: 1) piezoelectric polymers, 2) electrorheological fluids, and 3) electrostatic softening. This work aims to gain simple yet insightful ways to determine the potential of these methods without focusing on the precise modeling. Analytical models of FWMAV wing designs that include control approaches based on these three methods are used to calculate the achievable lift force modifications after activating these methods. The lift force production as a result of a wing flapping motion is determined using a quasi-steady aerodynamic model. Both piezoelectric polymers and electrostatic softening are found to be promising in changing the structural properties and, hence, the lift force production of FWMAV wings. For the control of lightweight FWMAV designs, numerical simulations reveal a promising roll maneuverability due to the induced lift force difference between a pair of opposite wings. Although applied to a specific FWMAV design, this work is relevant for control of small, lightweight, possible compliant, vibrating structures in general.

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Section: Methods To Induce Structural Property Changesmentioning

confidence: 99%

Methods to actively modify the dynamic response of cm-scale FWMAV designs

Peters

Goosen

Keulen

2016

Smart Mater. Struct.

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“…First, the average thickness is not adequate to reflect the real hawkmoth wing thickness distribution considering its morphological complexity. Second, the wing with prescribed dimensions and mass can be easily fabricated using a foam sheet (Expanded PolyStyrene) (Peters et al, 2017) in case artificial wings are needed for futural experimental study. A harmonic sweeping motion, ϕ(t) = ϕ m sin(2π f t), is applied to drive the wing, where the amplitude ϕ m is set to 60 • and f is the flapping frequency.…”

Section: Validation Of the Proposed Twist Modelmentioning

confidence: 99%

An efficient fluid–structure interaction model for optimizing twistable flapping wings

Goosen

Keulen

2017

Journal of Fluids and Structures

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Spanwise twist can dominate the deformation of flapping wings and alters the aerodynamic performance and power efficiency of flapping wings by changing the local angle of attack. Traditional Fluid-Structure Interaction (FSI) models, based on Computational Structural Dynamics (CSD) and Computational Fluid Dynamics (CFD), have been used to investigate the influence of twist on the power efficiency. However, it is impractical to use them for twist optimization due to the high computational cost. On the other hand, it is of great interest to study the optimal twist of flapping wings. In this work, we propose a computationally efficient FSI model based on an analytical twist model and a quasi-steady aerodynamic model which replace the expensive CSD and CFD methods. The twist model uses a polynomial to describe the change of the twist angle along the span. The polynomial order is determined based on a convergence study. A nonlinear plate model is used to evaluate the structural response of the twisted wing. The adopted quasi-steady aerodynamic model analytically calculates the aerodynamic loads by including four loading terms which originate from the wing's translation, rotation, their coupling and the addedmass effect. Based on the proposed FSI model, we optimize the twist of a rectangular wing by minimizing the power consumption during hovering flight. The power efficiency of optimized twistable and rigid wings is studied. Comparisons indicates that the optimized twistable wings exhibit power efficiencies close to the optimized rigid wings, unless the pitching amplitude at the wing root is limited. When the pitching amplitude at the root decreases by increasing the root stiffness, the optimized rigid wings need more power for hovering. However, with the help of wing twist, the power efficiencies of optimized twistable wings with a prescribed root stiffness are comparable with the twistable wings with an optimal root stiffness. This observation provides an explanation for the different levels of twist exhibited by insect wings. The high computational efficiency of the proposed FSI model allows further application to parametric studies and optimization of flapping wings. This will enhance the understanding of insect wing flexibility and help the design of flexible artificial wings for flapping wing micro air vehicles.

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“…For insects, there are several ways to achieve minor stiffness changes, including the vein blood circulation (Hou et al, 2014), wing warping (Ristroph and Childress, 2014). For FWMAVs, there also exist many approaches to tune the wing stiffness, e.g., piezoelectric polymers, electrorheological fluids, and electrostatic softening (Peters et al, 2015;Peters, 2016).…”

Section: Influence Of Lift Constraintsmentioning

confidence: 99%

“…For FWMAVs, there also exist many approaches to tune the wing stiffness, e.g. piezoelectric polymers, electrorheological fluids, and electrostatic softening (Peters et al 2015, Peters 2016).…”

Section: Influence Of Lift Constraintsmentioning

confidence: 99%

Optimal pitching axis location of flapping wings for efficient hovering flight

Qi¹,

Goosen²,

Keulen³

2017

Bioinspir. Biomim.

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Flapping wings can pitch passively about their pitching axes due to their flexibility, inertia, and aerodynamic loads. A shift in the pitching axis location can dynamically alter the aerodynamic loads, which in turn changes the passive pitching motion and the flight efficiency. Therefore, it is of great interest to investigate the optimal pitching axis for flapping wings to maximize the power efficiency during hovering flight. In this study, flapping wings are modeled as rigid plates with non-uniform mass distribution. The wing flexibility is represented by a linearly torsional spring at the wing root. A predictive quasi-steady aerodynamic model is used to evaluate the lift generated by such wings. Two extreme power consumption scenarios are modeled for hovering flight, i.e. the power consumed by a drive system with and without the capacity of kinetic energy recovery. For wings with different shapes, the optimal pitching axis location is found such that the cycle-averaged power consumption during hovering flight is minimized. Optimization results show that the optimal pitching axis is located between the leading edge and the mid-chord line, which shows close resemblance to insect wings. An optimal pitching axis can save up to 33% of power during hovering flight when compared to traditional wings used by most of flapping wing micro air vehicles (FWMAVs). Traditional wings typically use the straight leading edge as the pitching axis. With the optimized pitching axis, flapping wings show higher pitching amplitudes and start the pitching reversals in advance of the sweeping reversals. These phenomena lead to higher lift-to-drag ratios and, thus, explain the lower power consumption. In addition, the optimized pitching axis provides the drive system higher potential to recycle energy during the deceleration phases as compared to their counterparts. This observation underlines the particular importance of the wing pitching axis location for energy-efficient FWMAVs when using kinetic energy recovery drive systems.

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Active Control of the Hinge of a Flapping Wing with Electrostatic Sticking to Modify the Passive Pitching Motion

Cited by 3 publications

References 19 publications

Methods to actively modify the dynamic response of cm-scale FWMAV designs

Methods to actively modify the dynamic response of cm-scale FWMAV designs

An efficient fluid–structure interaction model for optimizing twistable flapping wings

Optimal pitching axis location of flapping wings for efficient hovering flight

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