Multiple Trajectories Generation to Realize Stable Flight of Kites in Airborne Wind Energy System

Although kites are expected to be useful for airborne wind energy systems, their autonomous control is remaining as a difficult problem. In some research, stability was verified around limit cycles and that was adapted to the kite control problem. However, the local stability around only one limit cycle can be verified with such solutions. In this paper, in order to operate kite more stably, multiple trajectories are generated by optimal control, and feedback controllers are designed for each trajectory. A closed trajectory is generated as the reference trajectory. Other surrounding trajectories are generated to converge at points on the reference trajectory. Feedback gain is obtained by time-varying linear quadratic regulator and stability verified area with such controller is computed. The effect of multiple trajectories on the stability is confirmed by simulation, and the direction of method extension is discussed.