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AWE workshop 23-24 May 2012
Automated Flight and Recent Developments of Kite Power at TU Delft AWE workshop 23-24 May 2012, KU Leuven, Belgium Roland Schmehl
2 AWE workshop 23-24 May 2012
Current demonstrator system Kite Power Technology Outline
• Demonstrator system • Autopilot development • Modeling & simulation • Research group
3 AWE workshop 23-24 May 2012
Kite power system demonstration April 2012, Valkenburg, the Netherlands
Demonstrator system
4 AWE workshop 23-24 May 2012
Demonstrator system Pumping kite working principle
Traction phase: high cable force due to crosswind flight manoeuvers
Recovery phase: low cable force due to depowering (flagging) of kite
5 AWE workshop 23-24 May 2012
Demonstrator system Ground station
Kite power system demonstration
Global Windday 2010, Lelystad, the Netherlands
6 AWE workshop 23-24 May 2012
LEI tube kites
25 m2 bow kite G2 with bridle for improved depower
Demonstrator system
7 AWE workshop 23-24 May 2012
LEI tube kites
25 m2 bow kite G2 with bridle for improved depower
Demonstrator system
8 AWE workshop 23-24 May 2012
Control pod Demonstrator system
9 AWE workshop 23-24 May 2012
System test at Valkenburg
• Altitude: 150 – 300 m • Flight vel: 70 – 90 km/h • Cycle mean power: 6.5 kW • Wing loading: 30 kg/m2
Demonstrator system
11 AWE workshop 23-24 May 2012
Autopilot development
12 AWE workshop 23-24 May 2012
• Power output determined by
• FT tether force, vr reel velocity
• Aim: Constant power output
• max. force by crosswind trajectories (figure-of-8)
• control reeling velocity to keep power constant
• Need for trajectory tracking controller
Principle Control Structure
!
t rP F v const= × »
Autopilot development
13 AWE workshop 23-24 May 2012
Geodesic Distance
( ) ( )1cos sinK C Cvd d c c-= × ¾¾® = - × -r r &
• Kite velocity projected onto local tangent plane
• Geodesic distance decreases depending on orientation
Autopilot development
14 AWE workshop 23-24 May 2012
• Control task: Minimize geodesic distance
• Solution: Control yaw angle χ, so that kite smoothly aligns
• Lack of validated kite models à empirical yaw correlation
• c1, c2 constants, vapp apparent wind speed, PS steering input (function of steering line length), G(Ψ) gravitational term (orientation in resp. to gravity)
Empirical System Model
( )!
sin 0Cvd c c= - × - <&
( )1 2app Sc v P c Gc » × × + × ψ&
Autopilot development
15 AWE workshop 23-24 May 2012
Empirical System Model: Results Autopilot development
16 AWE workshop 23-24 May 2012
• Cascaded control structure:
• Feedback linearization: Independent controller design
• Bearing Controller: Determine χcmd that would decrease δ
• Attitude Controller: Minimize orientation error χcmd –χ
• Adaption to increase robustness:
• Comparison of linearization quality with reference (MRAC)
• Superposition of adaption signal onto control signal
Tracking Controller Autopilot development
17 AWE workshop 23-24 May 2012
Simulation Results Autopilot development
18 AWE workshop 23-24 May 2012
Experimental Results 22 May 2012 Autopilot development
19 AWE workshop 23-24 May 2012
Modelling & simulation
20
Modeling & simulation Dynamic processes affecting kite operation
Structural dynamics
Fluid dynamics
Flight dynamics
FSI
FSI = Fluid-Structure Interaction
21 AWE workshop 23-24 May 2012
Modeling & simulation Model complexity
22 AWE workshop 23-24 May 2012
Modeling & simulation Structural submodel
Canopy à triangular, three node shell elements • Total Lagrangian formulation • Bending + Membrane (Felippa) • Use real material properties
Inflatable LE/struts à Beam elements • Total Langrangian formulation • Based on Euler-Bernoulli • Fitted material properties from experiments
23 AWE workshop 23-24 May 2012
Modeling & simulation Aerodynamic submodel
• Expand Cl, Cd to 5 forces • Keep Cm constant. • Assign weights with variations • Compare to CFD
24 AWE workshop 23-24 May 2012
Modeling & simulation Model complexity
25 AWE workshop 23-24 May 2012
26 AWE workshop 23-24 May 2012
Research group Core staff 2012 • Prof. dr. Wubbo Ockels
Director ASSET institute, chairholder
• Dr. Roland Schmehl
Associate professor, head of research group
• Aart de Wachter, MSc
Project manager Kite Power / Laddermill
• Rolf van der Vlugt, MSc
Kite development, mechanical engineering
• Uwe Fechner, MSc
Electronics, embedded systems
• Sergiy Ulyashyn, MSc
Electronics, embedded systems
• Claudius Jehle
• Allert Bosch
27 AWE workshop 23-24 May 2012
• Friesland Fernijt II (136 kEuro), 2010
> Development of control pod • Rotterdam Climate Initiative (1.6 MEuro), running
> Development & commercialization of complete system
Research group Co-funding 2010-2012
28 AWE workshop 23-24 May 2012
• ASSET positioned as interfaculty institute within TU Delft: • Aerospace Engineering • Electrical Engineering & Computer Science • Industrial Design • Mechanical Engineering
• MSc course “Kite Power Generation & Transportation”
2010: 12 students, 2011: 26 students, 2012: 45 students
• MSc course “Wind Power” (50% kite power) 2011: 49 students, 2012: 82 students
• Currently 10 MSc graduate researchers, tendency rising (especially from Germany)!!!
Research group Educational involvement
29
Thank you for your attention
Web: www.kitepower.eu Email: [email protected] Twitter: www.twitter.com/kite_power