Urban Fasel

Urban Fasel
Imperial College London | Imperial · Department of Aeronautics

Doctor of Sciences (Dr. sc. ETH Zurich)

About

32
Publications
12,373
Reads
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344
Citations
Citations since 2017
31 Research Items
342 Citations
2017201820192020202120222023020406080100120140
2017201820192020202120222023020406080100120140
2017201820192020202120222023020406080100120140
2017201820192020202120222023020406080100120140
Additional affiliations
October 2020 - present
University of Washington Seattle
Position
  • PostDoc Position
Education
May 2016 - August 2020
ETH Zurich
Field of study
  • Mechanical Engineering
February 2014 - March 2016
ETH Zurich
Field of study
  • Mechanical Engineering
September 2010 - September 2013
ETH Zurich
Field of study
  • Mechanical Engineering

Publications

Publications (32)
Article
Aeroelastic structures, from insect wings to wind turbine blades, experience transient unsteady aerodynamic loads that are coupled to their motion. Effective real-time control of flexible structures relies on accurate and efficient predictions of both the unsteady aeroelastic forces and airfoil deformation. For rigid wings, classical unsteady aerod...
Preprint
Full-text available
Accurate and agile trajectory tracking in sub-gram Micro Aerial Vehicles (MAVs) is challenging, as the small scale of the robot induces large model uncertainties, demanding robust feedback controllers, while the fast dynamics and computational constraints prevent the deployment of computationally expensive strategies. In this work, we present an ap...
Preprint
Full-text available
Sparse identification approaches are effective tools for identifying non-linear systems using response data. In the classic aeroelasticity literature, panel-flutter partial differential equation (PDE) models exhibit a variety of non-linear dynamic behaviours. On the basis of the parameters of these models, static and dynamic pre- and post-critical...
Preprint
Full-text available
The single, double, and triple pendulum has served as an illustrative experimental benchmark system for scientists to study dynamical behavior for more than four centuries. The pendulum system exhibits a wide range of interesting behaviors, from simple harmonic motion in the single pendulum to chaotic dynamics in multi-arm pendulums. Under forcing,...
Article
Full-text available
Sparse model identification enables the discovery of nonlinear dynamical systems purely from data; however, this approach is sensitive to noise, especially in the low-data limit. In this work, we leverage the statistical approach of bootstrap aggregating (bagging) to robustify the sparse identification of the nonlinear dynamics (SINDy) algorithm. F...
Preprint
Full-text available
Sparse model identification enables the discovery of nonlinear dynamical systems purely from data; however, this approach is sensitive to noise, especially in the low-data limit. In this work, we leverage the statistical approach of bootstrap aggregating (bagging) to robustify the sparse identification of nonlinear dynamics (SINDy) algorithm. First...
Preprint
Full-text available
Aeroelastic structures, from insect wings to wind turbine blades, experience transient unsteady aerodynamic loads that are coupled to their motion. Effective real-time control of flexible structures relies on accurate and efficient predictions of both the unsteady aeroelastic forces and airfoil deformation. For rigid wings, classical unsteady aerod...
Preprint
Full-text available
Automated data-driven modeling, the process of directly discovering the governing equations of a system from data, is increasingly being used across the scientific community. PySINDy is a Python package that provides tools for applying the sparse identification of nonlinear dynamics (SINDy) approach to data-driven model discovery. In this major upd...
Preprint
Full-text available
Many dynamical systems of interest are nonlinear, with examples in turbulence, epidemiology, neuroscience, and finance, making them difficult to control using linear approaches. Model predictive control (MPC) is a powerful model-based optimization technique that enables the control of such nonlinear systems with constraints. However, modern systems...
Article
Full-text available
A novel approach to reduced-order modeling of high-dimensional systems with time-varying properties is proposed. It combines the problem formulation of the Dynamic Mode Decomposition method with the concept of balanced realization. It is assumed that the only information available on the system comes from input, state, and output trajectories, thus...
Article
Full-text available
Morphing wings are expected to have transformative impact on future transportation and energy systems. To enable analysis and optimization of morphing wings, efficient numerical models are critically important. In this work, we present an accurate and tractable reduced-order model embedded in a genetic-algorithm-based optimization framework. The mo...
Preprint
Full-text available
A novel approach to reduced-order modeling of high-dimensional time varying systems is proposed. It leverages the formalism of the Dynamic Mode Decomposition technique together with the concept of balanced realization. It is assumed that the only information available on the system comes from input, state, and output trajectories generated by numer...
Article
This work introduces a novel structural concept for morphing wings, based on carbon-fiber reinforced polymer (CFRP) lattice structures. Conventional wing spars and ribs are replaced by CFRP rods, which are arranged with varying orientation and distribution within a load-carrying wing skin. A new structural parametrization is introduced to define th...
Conference Paper
The paper proposes a novel approach to data-driven reduced-order modeling which combines the Dynamic Mode Decomposition technique with the concept of balanced realization. The information on the system comes from input, state, and output trajectories, and the goal is to derive a linear low-dimensional input-output model approximation. % of the syst...
Poster
Full-text available
The design and computational model of a representative multi-megawatt airborne wind energy (AWE) system operated in pumping cycles is presented [1], together with a simulation framework that accounts for the flight dynamics of the fixed wing aircraft and the sagging of the tether, combining this with flight control and optimisation strategies to de...
Article
Full-text available
In this paper, we present the design and computational model of a representative multi-megawatt airborne wind energy (AWE) system, together with a simulation framework that accounts for the flight dynamics of the fixed-wing aircraft and the sagging of the tether, combining this with flight control and optimisation strategies to derive the power cur...
Conference Paper
This work presents the design, optimization and testing of a novel lattice-structure based morphing wing. The lattice-structure concept spans a large design space, including the possibility to vary among others material, number, distribution and the orientation of the lattice rods. The used parametrization scheme considers both the positioning of t...
Article
Full-text available
Accurate and efficient aeroelastic models are critically important for enabling the optimization and control of highly flexible aerospace structures, which are expected to become pervasive in future transportation and energy systems. Advanced materials and morphing wing technologies are resulting in next-generation aeroelastic systems that are char...
Article
Full-text available
Large design and manufacturing effort for high load carrying composite structures results from anisotropic material behavior, tedious curing or forming conditions as well as high sensitivity to manufacturing defects. Such challenges limit the design freedom and result in large cost and time effort. A novel design approach is proposed to realize loa...
Article
Flying wings achieve their roll, pitch, and yaw controllability exclusively through spanwise variations of lift and drag due to the lack of an empennage. Instead of using conventional control surfaces, which increase the aerodynamic drag due to gaps and discontinuities, a morphing structure can be employed. This work considers a previously develope...
Preprint
Full-text available
Accurate and efficient aeroelastic models are critically important for enabling the optimization and control of highly flexible aerospace structures, which are expected to become pervasive in future transportation and energy systems. Advanced materials and morphing wing technologies are resulting in next-generation aeroelastic systems that are char...
Article
Full-text available
Continuous carbon fibre composite additive manufacturing opens up new possibilities for automated, cost-effective manufacturing of highly-loaded structures. This is achieved by the high design freedom of the process, allowing to tailor the fibre placement and by thereby fully exploiting the anisotropy and strength of the composite material. On the...
Article
Airborne wind energy (AWE) is a power production technique aiming to harvest energy from high-altitude winds through tethered aircraft. In the ground-based power generation concept, the aircraft flies dynamic trajectories at high flight speeds and lift coefficients, thus creating large lift forces. These forces drive a ground-based generator via a...
Article
The design of morphing structures requires attaining concurrently light-weight, load-carrying and shape adaptable systems that minimize complexity, actuation requirements and part count. Exploiting the external loads to produce local stiffness variations induced by elastic instabilities offers the potential to activate shape deformations purely pas...
Conference Paper
This work presents the design, optimization, manufacturing, and experimental characterization of a swept, camber-morphing, flying wing. By virtue of a novel actuation concept, combined with a compliant structural concept, camber deflections of sufficient amplitude to achieve controllability in roll and pitch are attained. The optimization, which ac...
Article
Airborne wind energy (AWE) vehicles maximize energy production by constantly operating at extreme wing loading, permitted by high flight speeds. Additionally, the wide range of wind speeds and the presence of flow inhomogeneities and gusts create a complex and demanding flight environment for AWE systems. Adaptation to different flow conditions is...
Article
Morphing systems able to efficiently adjust their characteristics to resolve the conflicting demands of changing operating conditions offer great potential for enhanced performance and functionality. The main practical challenge, however, consists in combining the desired compliance to accomplish radical reversible geometry modifications at reduced...

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Projects

Project (1)
Project
Develop an open source simulation framework for a multi-megawatt airborne wind energy reference system. https://github.com/awegroup/MegAWES