Kite Model with Bridle Control for Wind-Power Generation

A compact flight dynamics model of a kite is developed by using Lagrangian formulation. The lengths of the three ropes of the bridle and the tether of the kite depend on time and are used to implement an open-loop control scheme of the kite system. By imposing simple time-periodic control laws, two pumping strategies for wind-energy generation are explored. Periodic trajectories of the system and their stability properties (Floquet characteristic multipliers) are computed numerically. As the amplitudes of the figure-eight paths are increased, the system becomes more efficient but less stable. A cyclic-fold bifurcation is detected for a very large lateral displacement of the kite. The impact of the control-law parameters on the generated power, including the period and the amplitude, is investigated. The results indicate that a correct design of the control could provide an optimal energy-generation system and a robust scheme to exploit high-altitude winds.