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This paper presents a method of data-driven parametric Dynamic Mode Decomposition (p-DMD) to derive a linear parameter-varying reduced-order model (LPV-ROM) for the nonlinear aeroelasticity of highly flexible aircraft. It directly uses the data snapshots obtained at varying flight conditions, and encodes the physical understanding of the nonlinear model's polynomial dependency on flight conditions to produce a polynomial-dependent LPV-ROM. Therefore, this method can handle not only the equilibrium flight conditions but also the cases of continuously-varying flight conditions. In the numerical studies, a highly flexible cantilever wing and a slender vehicle built based on it are first studied with fixed angles of attack as the scheduling parameter. The comparisons between traditional linearization-based parametric modeling and the data-driven p-DMD modeling are performed to verify the modeling accuracy. The results demonstrate that the current p-DMD modeling method can capture the aeroelastic and flight dynamic responses of highly flexible aircraft in both time and frequency domains. In addition, the proposed p-DMD method is applied to the highly flexible aircraft in a perturbed longitudinal flight with varying angles of attack as the scheduling parameter. The nonlinear aeroelastic and flight dynamic data are compared with the simulation results of the data-driven p-DMD model. The comparison results demonstrate that it can accurately capture the non-equilibrium (or transient) aeroelastic and flight dynamic behaviors of such slender vehicles.

The paper addresses both active and passive flutter suppression for highly flexible wings using piezoelectric transduction. The piezoelectric effect is included in a strain-based geometrically nonlinear beam formulation. The resulting structural dynamic equations for multifunctional beams are then coupled with a finite-state unsteady aerodynamic formulation, allowing for piezoelectric energy harvesting and actuation with the nonlinear aeroelastic system. With the development, it is possible to provide an integral aeroelastic and electromechanical solution of concurrent active piezoelectric control on and energy harvesting from wing vibrations, with the consideration of the geometrical nonlinear effects of the slender multifunctional wings. The energy harvesting system can provide an additional damping effect on the wing as well as its harvesting capability. In this paper, an LQG controller is developed for the active control of wing limit-cycle oscillations due to the onset of flutter instability. The controller demonstrates effective flutter control capability. Furthermore, a concurrent active vibration control and energy harvesting can also be realized for the multifunctional wing system with embedded piezoelectric materials., Meeting Information: First International Symposium on Flutter and its Application (May 15-17, 2016. Mielparque-tokyo), Minato-ku, Tokyo, Japan, Physical characteristics: Original contains color illustrations, 形態: カラー図版あり

We propose a new approximate method for counting the number of the solutions for constraint satisfaction problem (CSP). The method derives from the partition function based on introducing the free energy and capturing the relationship of probabilities of variables and constraints, which requires the marginal probabilities. It firstly obtains the marginal probabilities using the belief propagation, and then computes the number of solutions according to the partition function. This allows us to directly plug the marginal probabilities into the partition function and efficiently count the number of solutions for CSP. The experimental results show that our method can solve both random problems and structural problems efficiently., Comment: 14 pages, 2 figures, 3 tables

The University of Michigan has designed and is currently building an unmanned aerial vehicle, denoted X-HALE, which is aeroelastically representative of very flexible aircraft. The objective of this test bed is to collect unique data of the geometrically nonlinear aeroelastic response coupled with the flight dynamics to be used for future code validation. The aircraft will present specific aeroelastic features (e.g., coupled rigid/elastic body instability, large wing deflection during gust, etc.) that can be measured in flight. Moreover, the airframe construction choice is such that the elastic, inertial and geometric properties can be well characterized. These are requirements driven by the need of the collected data to be used to support validation of coupled nonlinear aeroelastic/flight dynamics codes., Presented at the 51st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference 12 - 15 April 2010, Orlando, Florida.