Negative aerodynamic damping causes tower vibrations on turbines with stall rotors. Under certain conditions, these vibrations may rise to a level that causes a shutdown. Active stall turbines have a pitch system, and the objective of the work was to develop pitch control algorithms which would minimise the probability of tower vibrations rising to the shutdown level. The results of a root caus...

Experiments have been carried out at sub-critical Reynolds number to investigate free-to-roll motions induced by forebody and/or wings complex flow on a 30° swept back nonslender wings-slender body-model for static and dynamic (pitch-up) cases. For the dynamic (pitch-up) case it has been observed that roll amplitude decreases and lag increases with increase in pitching speed. Decrease in roll a...

A stability analysis is conducted on the proposed three-time scale singular perturbation control that is applied to a Radio/Control helicopter on a platform to regulate its vertical position. The control law proposed allows to achieve the desired altitude by either selecting a desired collective pitch angle or a desired angular velocity of the blades.

Several approaches for modelling the longitudinal aerodynamic coefficients of a fighter aircraft at high angles of attack, including the unsteady effects are presented. A traditional approach where the model of the coefficient arises in the form of the steady and unsteady effects, the unsteady effect being modelled by means of transfer functions. The second approach uses an internal variable de...

By combining optical triangulation with the comb-fringe technique and dual-channel telemetry, wing kinematics and body attitudes accompanying muscle activities of free-flying male hawkmoths were recorded synchronously when they performed flight manoeuvres elicited by a female sex pheromone. The results indicate that the wing leading edge angular position at the ventral stroke reversal, which ca...

The objective of the paper is to develop a novel intelligent pitch control system of a 2MW wind turbine driven by variable-speed hydraulic pump-controlled system. For realizing the intelligent pitch controller, self-organizing fuzzy sliding mode control, which combines fuzzy sliding mode control and self-organizing modifier, is proposed. In order to verify the proposed concept experimentally, a...

This note examines pattern-recognition and track reconstruction issues for the scintillator tracking system of the UT Maya Muon detector [1]. The basic geometry and performance characteristics of the tracking system are described in [2]. As described in the references, the scintillator strips are assumed to form helices of a fixed pitch-angle θs on their respective tracking layers. The tracking...

In this research paper an energy system composed of three energy conversion devices namely, photovoltaic panels, a wind turbine, and a battery is proposed. This controller directs power to a fixed voltage DC bus. The fixed voltage bus supplies the load, while the excess power is directed to the batteries. Simulation and control of a hybrid PVwind generator system connected to the load are prese...