Hardware and Communication Issues of
Airborne Wind Energy Rotational Start-up
Hammad Ahmad, Andrew Wagner, Kurt Geebelen, Moritz Diehl
KU Leuven, Belgium
Abstract
The computational work is compliment with the experimental testing and validation in a controlled environment. An experimental
test set-up is built at KU Leuven for modelling, control and estimation simulations’ validation with hardware-in-the-loop. The idea
was to build the system with commercial off the shelf items. But at the same time the maintainability, reliability and robustness
issues are also accounted for. Current set-up utilises 1 m span aircraft with 800Hz IMU with carousel mounted high resolution
cameras for state estimation. The control surfaces in the aircraft are elevators (longitudinal control) and ailerons (lateral control).
Hardware set-up
Carousel and aircraft interaction
Aim:
• To provide scalable, maintainable and robust system
• To perform indoors model validation, control and estimation experiments
Load imbalance in the carousel structure yield mechanical oscillations in the system.
Carousel arm oscillates in the horizontal plane at the frequency
of the carousel (1 Hz)
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Inertial Measurement Unit Alignment
Latencies in the system
The cameras are triggering at 10 Hz (with an external trigger),
and the data transferred with a 75ms delay. The blobs (red,
green and blue markers) are extracted with a computation delay of 75 ms The carousel position is measured by an encoder
at sampling frequency of 10 Hz.
AWE tether
• Three pairs of copper. The maximum distance for communication over standard Ethernet cable is 90 meters.
• Cable enclosed in sheath braided Kevlar for mechanical
strength with the tether outer diameter of 3.6mm (minimum
drag requirement)
Future work
• Upgrading the aircraft to 2m span
• Upgrading the power electronics for on-board propeller
• Safe communication over power for distances above 100m.
• Tether with minimum drag and higher mechanical strength.