Repeated simulations with a point-mass model show our control approach to be robust against turbulence, and simulations with a multi-body model of a flexible kite validate our modeling assumptions. The controller adapts the estimates of these control derivatives based on tracking performance. We show how the zero-term of the linearization can be measured directly using on-board sensors, and how in this way the control law comes to depend on the control derivatives of the aerodynamic kite model only. In order to facilitate model inversion we linearize the turning angle dynamics in the steering control input, and apply energy methods to derive a stabilizing feedback law. We show how the differential-geometric notion of turning angle can be used as a one-dimensional representation of the kite trajectory, and how this leads to a single-input single-output tracking problem. Kites commonly have a single control input available for steering. The latter is especially important for control of flexible kites, which are hard to model accurately in a point-mass or rigid-body framework. Compared to alternative approaches, such as model predictive control, our approach has three major advantages: a stability proof, ease of implementation, and minimal modeling requirements. In this thesis we present a novel solution to the kite trajectory tracking problem using an explicit control law. The front blade should work fruitfully at the larger radius and had better not work at the smaller radius for giving plenty of wind energy to the rear wind rotor, taking account of the flow interaction between both wind rotors. Continuously, this paper investigates experimentally and numerically the flow condition around the wind rotors to know the flow interactions between the front and the rear wind rotors, and optimizes the blade profile in the front wind rotor. The unique rotational behaviors of the tandem wind rotors and the fundamental performances of the unit have been discussed at the previous paper. The large-sized front wind rotor and the small-sized rear wind rotor drive, as for the upwind type, the inner and the outer rotational armatures, respectively, in keeping the rotational torque counter-balanced between both wind rotors/armatures. The authors have invented the superior wind power unit, which is composed of the tandem wind rotors and the double rotational armature type generator without the traditional stator. A relationship between post-stall lift and drag peak magnitude and blockage is hypothesised for conventional tunnel data that persists even after the application of corrections. The double slatted tolerant tunnel has the best performance overall based on similarity of results for the aerofoils but post-stall force peaks are significantly lower than for the conventional tunnel. The single slatted wall data is similar to that from the corrected conventional tunnel. Results are given for the best single and double slatted wall tunnels, chosen based on which tunnel wall porosity gives the closest force measurements for the two aerofoils. The tolerant tunnel does not need any corrections. Conventional tunnel results require processing with blockage corrections that are less than ideal for application to stalled aerofoils. The tolerant tunnel has transversely slotted walls and can be configured with either single or double slatted walls, with adjustable wall porosity. New data is presented for two different-sized NACA-0012 aerofoils, taken in blockage-tolerant and conventional solid-walled wind tunnels. Discrepancies between existing studies are shown to affect modelled performance of VAWTs, with wind tunnel blockage identified as a possible cause. Abstract Good quality post-stall aerofoil force data at low Reynolds numbers is needed for the analysis of vertical-axis wind turbines (VAWTs).
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