The implementation of such systems has been held back by significant control challenges, due to the unpredictable wind turbulence, and nonlinear and open-loop, unstable flying dynamics.
For the project the group used three commercially produced power kites with areas ranging from 6 to 12 m2. The kites were capable of developing 50 to 300kg of force from a wind speed of just 4m/s.
The steering of the kite through the pumping cycles was achieved at the ground unit by changing the lengths of the kite’s two steering lines.
To help determine the position of the kite, the ground unit was fitted with sensors to measure the angle of the main line of the kite. Wind speed and direction, and lines forces were also measured. The kite itself was equipped with an inertial measurement unit consisting of three accelerometers, three magnetometers, three gyroscopes, a barometer, and a GPS. The data from these sensors was transmitted to the ground unit via a radio link.
A Mobile real-time target machine from Speedgoat was leveraged to act as a controller. Advanced algorithms to autonomously fly power cycles, stabilize the system, and to maximize power generation were designed with Simulink.
A real-time application was created from the Simulink model using Simulink Real-Time, and to establish communication with sensors and actuators, Speedgoat driver blocks for analog and digital I/O were used.