High-fidelity modelling and feedback control of bio-inspired membrane wings

This work is a numerical investigation on the performance of integrally actuated two-dimensional membrane wings made with dielectric elastomers. A high-fidelity model based on the direct numerical integration of the unsteady Navier-Stokes equations is coupled with a geometrically non-linear structur...

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Bibliographic Details
Main Author: Buoso, Stefano
Other Authors: Palacios Nieto, Rafael
Published: Imperial College London 2015
Subjects:
Online Access:http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686327
Description
Summary:This work is a numerical investigation on the performance of integrally actuated two-dimensional membrane wings made with dielectric elastomers. A high-fidelity model based on the direct numerical integration of the unsteady Navier-Stokes equations is coupled with a geometrically non-linear structural model. The rate-dependent constitutive law for the dielectric elastomer is based on a non-linear formulation, and it has been validated against experimental data. In addition, the implementation of the aeroelastic framework has been verified against the relevant literature for the low-Reynolds number flows investigated in this dissertation. Numerical simulations of the open-loop dynamics of the actuated membrane, in good agreement with experimental observations, show that integral actuation offers enough authority in the control of the wing aerodynamic performance. Dielectric elastomers can then be used as embedded actuators, coupling the advantages of passive membranes with a simple and lightweight control mechanism. Further, this work also proposes a model-reduction methodology for the fully coupled system to aid control system design. The low-order description of the actuated system can capture the main system dynamics, and can be used for the design of the control scheme of the wing. Proportional-Integral-Derivative and Linear Quadratic Gaussian feedback controllers, designed using the reduced-order model, are finally implemented in the high-fidelity model for the rejection of flow disturbances. Results show that the wing aerodynamic performance is noticeably enhanced through the actuation as the disturbances on the lift in case of gusts can be reduced up to 60%.