Guest Lecture by Prof. Spyros Voutsinas, National Technical University of Athens, on Vortex Methods for Wind Turbines

8 June 2015 at 15:15-16:00
Room T6, Marine Technology Centre

Guest Lecture by Prof. Spyros Voutsinas, National Technical University of Athens, on Vortex Methods for Wind Turbines

8 June 2015 at 15:15-16:00
Room T6, Marine Technology Centre

Abstract:

What we call today “Vortex methods” appeared in various forms since 1930, when Rosenhead first introduced the notion of point vortices and formulated a numerical method for predicting the roll-up of the wake of an aircraft wing. Well known variants are the lifting-line and lifting surface methods for wings and rotors as well as the panel and boundary element methods used in aerodynamics. Although not always specifically said, all vortex methods are based on Helmholtz’s decomposition and Green’s theorem. The context is to solve the flow equations in Lagrangian (material) co-ordinates following the evolution of a set of markers. Depending on the choice one is making for the markers a variety of vortex methods can be defined. The older vortex methods used vortex segments or vortex panels as markers for the representation of vortex filaments and vortex sheets. In the late 70’s  point vortices were first  in 3D flows by Rehbach who also indicated the need for regularization. Also a few years earlier Chorin was the first to extend the point vortex method to viscous 2D flows. The elegance and simplicity of vortex methods attracted a lot of researchers from different fields. In the early 80’s Beale and Majda provided mathematical justification of the regularized point vortex methods in 2D and 3D which are today known as vortex particle or blob methods. Since then a long list of theoretical and applied contributions has been published covering a very wide range of topics, including wind energy.

This lecture aims at providing an overview on how vortex methods can be used in wind turbine aerodynamics and aeroelasticity. While the emphasis will be on the particle version of vortex methods, other particle methods will be briefly discussed. We will focus on cost reduction techniques (tree algorithms, Particle Mesh techniques), on viscous formulations though coupling to CFD and on aeroelastic simulations.

Representative results will be discussed in comparison to measurements and other (BEM & CFD) simulation methods addressing the range of applicability of vortex methods in connection to their accuracy/cost ratio. The talk will close with an outlook and a list of still open issues. 


Seminar on "Compositional Control Synthesis and Verification for Networks" by Professor Murat Arcak, U.C. Berkeley

Room B343, Elektro Bld. D, Gløshaugen
Tuesday 26 May at 09:15-11:00
Wednesday 27 May at 09:15-11:00
Thursday 28 May at 09:15-11:00

Seminar on "Compositional Control Synthesis and Verification for Networks" by Professor Murat Arcak, U.C. Berkeley

Room B343, Elektro Bld. D, Gløshaugen
Tuesday 26 May at 09:15-11:00
Wednesday 27 May at 09:15-11:00
Thursday 28 May at 09:15-11:00

Course description:

Control synthesis and performance verification techniques are severely limited in their scalability to large networks of interconnected components.   In this series of lectures we will address this problem with a compositional approach that derives network-level guarantees from structural properties of the components and their interconnection.

First we will review the classical notion of dissipativity and derive conditions under which a large-scale interconnection of dissipative components satisfies a prescribed network performance criterion.  Next we will exhibit practically important interconnection structures and discuss which dissipativity properties are compatible with such structures to verify performance.  We will then present a large-scale optimization technique that searches over dissipativity properties of each component simultaneously for this verification.   Along the way we will define useful variants of the dissipativity notion, such as equilibrium-independent dissipativity and dissipativity with a dynamic supply rate.  We will conclude these lectures with vistas for further research on compositional synthesis, including tools based on formal methods from computer science.  We will illustrate the results presented in these lectures with examples from multi-agent systems, communication networks, and traffic networks.  In doing so, we will exhibit useful structural properties inherent in these networks. 

Biography: 

Murat Arcak is a professor at U.C. Berkeley in the Electrical Engineering and Computer Sciences Department.  He received the B.S. degree from the Bogazici University, Istanbul, Turkey (1996) and the M.S. and Ph.D. degrees from the University of California, Santa Barbara (1997 and 2000). His research is in dynamical systems and control theory with applications to synthetic biology, multi-agent systems, and transportation. He received a CAREER Award from the National Science Foundation in 2003, the Donald P. Eckman Award from the American Automatic Control Council in 2006, the Control and Systems Theory Prize from the Society for Industrial and Applied Mathematics (SIAM) in 2007, and the Antonio Ruberti Young Researcher Prize from the IEEE Control Systems Society in 2014. He is a member of SIAM and a fellow of IEEE.


Guest Lecture by Dr Ahmed Chemori, University of Montpellier, France, on "Control of Underwater Vehicles: From Design to Real-Time Experiments"

18 May 2015 at 13:15-14:15
Auditorium T1, Marine Technology Centre

 

Guest Lecture by Dr Ahmed Chemori, University of Montpellier, France, on "Control of Underwater Vehicles: From Design to Real-Time Experiments"

18 May 2015 at 13:15-14:15
Auditorium T1, Marine Technology Centre

 


Guest Lecture by Professor Randal W. Beard, BYU, Utah, USA on "Research Activities in Small Unmanned Air Vehicles"

11 May 2015 at 10:15-11:00
Auditorium EL6, Gløshaugen

Guest Lecture by Professor Randal W. Beard, BYU, Utah, USA on "Research Activities in Small Unmanned Air Vehicles"

11 May 2015 at 10:15-11:00
Auditorium EL6, Gløshaugen

 

Abstract:  This talk will provide an overview of several research projects currently underway in the BYU Magicc Lab.  The first project that will discuss is relative navigation in GPS degraded environments.   There are many applications where GPS is either restricted or denied.   We have developed an architecture that uses a relative front end to navigate relative to key frames, and then opportunistically uses GPS measurements and SLAM-style loop closures in a back end process to provide global context.  We will show some recent flight results that demonstrate robustness to GPS failure and degradation.  The second project that we will discuss is the development of a sense and avoid system for small UAS.  We have developed a small radar system for air and ground based detection, and associated detection, tracking, and avoidance algorithms.  The third project is an autopilot design for a unique tailsitter aircraft.  We will focus on attitude estimation and the design of the transition trajectories.  Finally, we describe a project that focuses on robust tracking of multiple ground based targets from an airborne platform.  We will present a new multiple target tracking algorithm that is based on the random sample consensus (RANSAC) algorithm that is widely used in computer vision.  A recursive version of the RANSAC algorithm will be discussed, and its extension to tracking multiple dynamic objects will be explained.  The performance of R-RANSAC will be compared to state of the art target tracking algorithms in the context of problems that are relevant to UAV applications.

Biography:  Randal W. Beard received the B.S. degree in electrical engineering from the University of Utah, Salt Lake City in 1991, the M.S. degree in electrical engineering in 1993, the M.S. degree in mathematics in 1994, and the Ph.D. degree in electrical engineering in 1995, all from Rensselaer Polytechnic Institute, Troy, NY. Since 1996, he has been with the Electrical and Computer Engineering Department at Brigham Young University, Provo, UT, where he is currently a professor. In 1997 and 1998, he was a Summer Faculty Fellow at the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA. In 2006 and 2007 he was a visiting research fellow at the Air Force Research Laboratory, Munitions Directorate, Eglin AFB, FL. His primary research focus is autonomous control of small air vehicles and multivehicle coordination and control. He is a past associate editor for the IEEE Transactions on Automatic Control, the IEEE Control Systems Magazine, and the Journal of Intelligent and Robotic Systems.  He is a fellow of the IEEE, and an associate fellow of AIAA.

http://www.ee.byu.edu/faculty/beard/

Professor Randal W. Beard is the author of "Small Unmanned Aircraft. Theory and Practice". Princeton University Press, 2012.

http://uavbook.byu.edu


Guest Lectures by Dr Kari Tammi and Jackson Potter, VTT Technical Research Centre, Finland

8 May 2015 at 10:15-12:00
Room T3, Marine Technology Centre

 

Guest Lectures by Dr Kari Tammi and Jackson Potter, VTT Technical Research Centre, Finland

8 May 2015 at 10:15-12:00
Room T3, Marine Technology Centre

 

10:15-11:00 "Energy Flow Simulation Analysis for Optimizing Vessel Energy Efficiency" by Dr Kari Tammi

- Presents a tool developed at VTT for vehicle energy system analysis, based in Simscape

- The tool covers e.g. detailed frequency converter models, and ranges up to system level energy flows 

- Energy flows including production, waste heat recovery, and consumption in a ship have been analyzed

 

11:15-12:00 "Using and Improving the Steam System Model in a Ship Energy Flow Simulator" by Jackson Potter

- A drum boiler model based on a paper by Åstrom & Bell (2000) is modeled in Simscape

- The configuration of the ship's exhaust gas boiler pumps was studied, and several energy-saving alternative configurations are proposed

- Empirical models that predict the temperature of gas through the exhaust gas boilers are added to the Ship Energy Flow Simulator


Guest Lectures Series by Dr Antonio Loría on Stability and Stabilization of Time-varying Systems

23 April 2015: 10:15-12:00 and 13:15-15:00
24 April 2015: 10:15-12:00 and 13:15-15:00
27 April 2015: 10:15-12:00 and 13:15-15:00
28 April 2015: 10:15-12:00 and 13:15-15:00
29 April 2015: 09:15-12:00 and 13:15-15:00
Room B343, Electro Building B, Gløshaugen

Guest Lectures Series by Dr Antonio Loría on Stability and Stabilization of Time-varying Systems

23 April 2015: 10:15-12:00 and 13:15-15:00
24 April 2015: 10:15-12:00 and 13:15-15:00
27 April 2015: 10:15-12:00 and 13:15-15:00
28 April 2015: 10:15-12:00 and 13:15-15:00
29 April 2015: 09:15-12:00 and 13:15-15:00
Room B343, Electro Building B, Gløshaugen

Summary of the seminar:

Lyapunov's direct method is widely regarded as a powerful method to study (Lyapunov) stability of dynamical systems. Originally introduced for nonlinear autonomous differential equations, modern extensions include discontinuous systems, systems with jumps, systems with impulsive dynamics, time delays, etc. This course focusses on the study of systems with smooth dynamics since in a number of engineering control problems "basic" nonlinear control theory may be used to design stabilizing controllers. However, in control of physical systems (robots, marine vehicles, motors, etc) realistic scenarios impose uncertainties in the parameters and the impossibility of measuring the whole system's state. Solving such problems through systematic Lyapunov-based design may rapidly become intractable only because of our inability to find a (control) Lyapunov function. Therefore, standard Lyapunov theory for nonlinear time-varying systems, as developed by Barbashin and Krasovskii in the 1950s may rapidly appear frustrating since rendering our analysis inconclusive.

In this course we study Lyapunov stability without a (strict) Lyapunov function via alternative methods which involve:

invariance principles and tools from real analysis (Barbalat);
integrability conditions (Panteley et al);
differential conditions with more than one auxiliary function (Matrosov);
feedback and cascade-interconnected systems (Panteley, Lora);.

The lectures are intended for PhD students and researchers willing to strengthen their knowledge in stability analysis of complex nonlinear systems. It is composed of 21 1-hr lessons

 

Short bio:

A. Loría was born in Mexico City, in 1969. He got the BSc degree in Electronic Systems Engineering from the "Monterrey Institute of Technological and Higher Studies (ITESM) in 1991. He got the DEA (~MSc) and PhD in Control Engineering degrees from the "University of Technology of Compiègne" in 1993 and 1996 respectively, both under the supervision of Romeo Ortega. From December 1996 till May 1997 he was a research fellow of the Department of Applied Mathematics at the University of Twente. From May through December 1997 he was a research fellow of the Department of Engineering Cybernetics at the Norwegian Institute of Science and Technology. From January through December 1998, he was an associate research engineer of the Center for Control Engineering and Computation, under the sponsorship of Prof. Petar Kokotovic and Prof. Andrew Teel. A. Loría occupies a permanent Research position at the French National Council of Scientific Research (CNRS) since 1999 (Senior Researcher since 2007) and is with Laboratoire de Signaux et Systèmes since 2001.


Guest Lecture by Dr Helge Aagaard Madsen, DTU Wind Energy (Risø), on Aerodynamic induction models for HAWT´s and VAWT´s in HAWC2 with recent updates

13 April 2015 at 15:15-16:00
Room T9, Marine Technology Centre

Guest Lecture by Dr Helge Aagaard Madsen, DTU Wind Energy (Risø), on Aerodynamic induction models for HAWT´s and VAWT´s in HAWC2 with recent updates

13 April 2015 at 15:15-16:00
Room T9, Marine Technology Centre

Abstract:

One of the consequences of the up-scaling of wind turbines is that the aerodynamic loading over the rotor isk has become more non-uniform caused by wind shear and the rotational sampling of the turbulence. The question is how well we model this effect in our aeroelastic codes based on the BEM theory. In HAWC2 this is taken into account as the BEM model is implemented in the grid points of a fixed grid covering the swept area. Modelling the impact of wake swirl and flow expansion is also commented on.

In order to improve the unsteady induction modelling close to the individual blades and in particular to improve the computation of aeroelastic damping a so-called near wake model has been developed. Originally the model has been developed by Beddoes for helicopter rotor applications. It is a simplified lifting line model for the individual blades taking into account only the first 90 deg. of the trailed vortices. The model will be shortly described and results from initial simulations with the near wake model in HAWC2 will be presented.

Recently, the HAWC2 code has been extended with the so-called Actuator Cylinder model for induction computations on VAWT´s. The model and the implementation are briefly described. A comparison with results from a number of other models is presented. 


AMOS Innovation: Executive Course

9-10 April 2015
DIGS

AMOS Innovation: Executive Course

9-10 April 2015
DIGS

This is a two-day executive course in the commercialization of research as part of AMOS’ innovation program.

The participants will learn tools and methods for commercialization and for making impact from research. Value creation through both new spin-offs and in existing industry will be discussed.

NTNU Technology Transfer facilitate this course together with the Intellectual Property Institute of Norway and AMOS’ management. Industry experts will also be invited.

Watch a short video about the course


Guest Lectures Series on Hydrodynamic Aspects of Marine Structures

9, 16 and 23 March 2015 at 13:15-16:00
Room T6, Marine Technology Centre, Tyholt

Guest Lectures Series on Hydrodynamic Aspects of Marine Structures

9, 16 and 23 March 2015 at 13:15-16:00
Room T6, Marine Technology Centre, Tyholt

1.
9 March 2015 at 13:15-16:00
Room T6, Marine Technology Centre, Tyholt
"Harmonic Polynomial Cell (HPC) methods and its applications in marine hydrodynamics"
Lecturer: Dr. Yanlin  Shao

2.
16 March 2015 at 13:15-16:00
Room T6, Marine Technology Centre, Tyholt
"Mesh generation and analysis for Computational Fluid Mechanics"
Lecturer: Dr. Giuseppina Colicchio

3.
23 March 2015 at 13:15-16:00
Room T6, Marine Technology Centre, Tyholt
"Wave impacts in sloshing flows"
Lecturer: Prof. Claudio Lugni


Guest Lecture by Prof. Jasna Prpić-Oršić, University of Rijeka, Croatia, on a Greener Approach to Ship Design and Optimal Route Planning

4 March 2015 at 13:15-14:00
Auditorium T1, Marine Technology Centre

Guest Lecture by Prof. Jasna Prpić-Oršić, University of Rijeka, Croatia, on a Greener Approach to Ship Design and Optimal Route Planning

4 March 2015 at 13:15-14:00
Auditorium T1, Marine Technology Centre

Abstract:

Basic characteristics of an efficient transportation are safety, cost effectiveness and friendliness with the environment. According to various environmental impact assessments, ocean-going vessels, as the most important part of maritime transportation industry, will have increasing influence on the global ecosystem in the near future. In the modern approach to ship design the problems related to energy efficiency and environmental protection must not be left aside. A methodology for estimating the attainable speed in moderate and severe sea is proposed. Reliable ship speed loss estimation under real environmental conditions allows a more accurate prediction of the power increase and fuel consumption as well as gas emissions from ships.

The objective is to improve ship design and performance taking into accounts the environmental issue, creating a so-called eco-efficient or “green” ship design. The problem is multidisciplinary and requires the joint work of experts in the naval architecture, mechanical engineering, marine engineering and other engineering field.

Presentation


Mini-course by Prof. Manfredi Maggiore, University of Toronto, Canada, on Reduction Principles for Hierarchical Control Design

18 February 2015 at 09:00-16:00
Room B343, Electro Building B, Gløshaugen Campus

Mini-course by Prof. Manfredi Maggiore, University of Toronto, Canada, on Reduction Principles for Hierarchical Control Design

18 February 2015 at 09:00-16:00
Room B343, Electro Building B, Gløshaugen Campus

Abstract

This mini-course presents a formulation of the hierarchical control design problem for nonlinear systems. The idea in hierarchical control design is to “divide and conquer” a complex control specification by decomposing it into a hierarchy of sub-specifications, each one typically easier to enforce than the original specification. The backstepping technique for equilibrium stabilization is a popular example of hierarchical control design.

Hierarchical control specifications arise naturally in modern robotics applications. To illustrate, the path following problem for vehicle formations involves a hierarchy of two specifications: first enforce the desired formation, then make the formation follow a pre-specified path in three-space. Enforcing the formation corresponds to stabilizing a subset $\Gamma_1$ of the vehicles’ state space; making the formation follow the path corresponds to stabilizing a second subset, $\Gamma_2$, contained in $\Gamma_1$. Thus in this context, hierarchical control design corresponds to the simultaneous stabilization of two nested invariant sets $\Gamma_2 \subset \Gamma_1$.

In this mini-course a framework is proposed in which hierarchical control design amounts to the simultaneous stabilization of a finite collection of nested controlled invariant sets. I will discuss so-called reduction principles as tools to address this stabilization problem. The theory will be used to solve two problems: the design of distributed controllers solving the circular formation stabilization problem for nonholonomic vehicles, and the design of almost-global position controllers for thrust-propelled underactuated vehicles. In the context of equilibrium stabilization of lower-triangular control systems, I will show that reduction principles allow one to improve the classical backstepping technique.

Biography

Manfredi Maggiore was born in Genoa, Italy. He received the Laurea degree in Electrical Engineering in 1996 from the University of Genoa and the PhD degree in Electrical Engineering from the Ohio State University, USA, in 2000. Since 2000 he has been with the Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Canada, where he is currently Professor. He has been a Visiting Professor at the University of Roma Tor Vergata (2001) and the University of Bologna (2007-2008). His research focuses on mathematical nonlinear control, and relies on methods from dynamical systems theory and differential geometry.


Guest Lecture by Prof. R. Andrew Schwartz, Michigan Technological University, on Model Updating of Spinning Beam Structures for Load Characterization and Structural Health Monitoring Applications

2 February 2015 at 15:15-16:00
Room T9, Marine Technology Centre, Tyholt

Guest Lecture by Prof. R. Andrew Schwartz, Michigan Technological University, on Model Updating of Spinning Beam Structures for Load Characterization and Structural Health Monitoring Applications

2 February 2015 at 15:15-16:00
Room T9, Marine Technology Centre, Tyholt

Abstract:

Structural health monitoring (SHM) relies on models to exploit damage-sensitive features in order to identify and characterize damage.  Mechanistic models that are able to incorporate damage behavior are preferred, as they can represent damage type and severity, as well as characterize the danger posed to the structure by hypothesized damage scenarios.  Fusion of data-driven models, realized from vibrational response data, with useful mechanistic models must be achieved in order to  make use of sensor data in this way.  In addition, low-order models are preferred for SHM owing to the need for such systems to operate autonomously and in near real time.  In this study, a mechanistic model, based on spinning finite elements with damped gyroscopic and coupled flexural torsional effects, is fused with a data-driven model, based on output-only cyclo-stationary stochastic subspace identification, for spinning beam structures using an adaptive simulated annealing algorithm.  The ultimate goal of the project is to incorporate fluid-structure interaction into the mechanistic model for use in load characterization and SHM of wind turbine structures.  Related work integrating novel 2D strain-sensing skins for damage detection is also presented.