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Introduction
Published in Yu Ding, Data Science for Wind Energy, 2019
The wind turbines considered here are the utility-scale, horizontal axis turbines. As illustrated in Fig. 1.1, a turbine, comprising thousands of parts, has three main, visible components: the blades, the nacelle, and the tower. The drive train and control system, including the gearbox and the generator, are inside the nacelle. While the vast majority of horizontal axis wind turbines use a gearbox to speed up the rotor speed inside the generator, there are also direct drive wind turbines in which the gearbox is absent and the rotor directly drives the generator. An anemometer or a pair of them can be found sitting on top of the nacelle, towards its rear end, to measure wind speed, whereas a vane is for the measurement of wind direction. Responding to changes in wind direction, yaw control is to rotate and point the nacelle to where the wind comes from. Responding to changes in wind speed, pitch control turns the blades in relation to the direction of the incoming air flow, adjusting the capability of the turbine to absorb the kinetic energy in the wind or the turbine’s efficiency in doing so.
Study on construction of driver model for obstacle avoidance using risk potential
Published in Maksym Spiryagin, Timothy Gordon, Colin Cole, Tim McSweeney, The Dynamics of Vehicles on Roads and Tracks, 2018
Ichiro Kageyama, Yukiyo Kuriyagawa, Atsushi Tsubouchi
In the first stage of this research, since it is assumed that obstacle avoidance is performed only by steering control, we consider using a quasi-stationary velocity model. In modeling using risk information, it is assumed that the driver is controlled by feed forward steering and feedback steering [3]. Feed forward steering is determined according to the course curvature. Therefore, the curvature is obtained from the minimum potential determined by the risk potential, and feed forward steering is determined using this. In the lateral control algorithm, feedback steering is divided into two parts, one is feedback for course tracking and the other is feedback on directional stability of the vehicle. In the feedback steering of course tracking, second order preview model is used. In this case, a nonlinear feedback model with feedback of the left and right risk difference is used. In the stabilization control for direction control, yaw rate feedback is used. Fig. 3 shows a summary of feed forward and these two feedbacks as a total driver model, which we proposed.
Precision Manufacturing
Published in Osita D. I. Nwokah, Yildirim Hurmuzlu, The Mechanical Systems Design Handbook, 2017
The electronic level is an instrument that measures small angles using the direction of gravity as a reference. A typical set-up for determining the pitch of an axis is shown in Figure 10.28. The two levels, A and B, are used differentially in one plane yielding the angular motion of one level relative to the other level. Level A is located in the tool location, and level B is located where the workpiece is mounted. These locations insure that the angular motions computed will be those that are experienced between the workpiece and the tool. To perform the measurement, the table is moved along its entire length, stopping at fixed distances along the length of the slideway. It is important that the table is brought to a complete stop at each point where the readings are taken. This permits the levels to stabilize so that accurate data can be recorded. The two levels are then read and the value from B is subtracted from A resulting in the relative angular motion between the two levels. The table is then moved to the next location where another reading is taken. This procedure is repeated until the angular motion for the entire axis is mapped. The roll of the slide may be measured by simply rotating the two levels 90° about the vertical axis and repeating the procedure. Yaw measurement requires the use of either a laser angular interferometer or an autocollimator.
Robust wake steering control design in a wind farm for power optimisation using adaptive learning game theory (ALGT) method
Published in International Journal of Control, 2023
Vahid Fazlollahi, Farzad A. Shirazi, Mostafa Taghizadeh, Shahin Siahpour
Understanding that interactions between turbines can affect wind farm power generation, cooperative control methods have been utilised for active wake redirection to maximise the total output power of wind farms. The wind turbines induction factor and yaw angle have been used as control inputs for this purpose. Notice that the axial induction factor can be changed by the generator torque and blade pitch angle. This factor is used to adjust the output power of wind turbines and utilised to rein the deceleration rate of the wind speed inside the wake. Hence, this factor affects the output power of wind turbines located downstream. To increase the total output power of wind farms, a collection of wind turbine induction factors and yaw angles have been used by Boersma et al. (2017), van der Hoek et al. (2019) and Goit and Meyers (2015). In the control of individual wind turbines, yaw control is mostly utilised to adjust the turbine rotor plane upright to the upcoming wind direction to gain the highest output power of the turbine. In wind farms, yaw control reduces the output power of the upstream individual turbines, but by redirecting the wake, it can increase the output power of the downstream wind turbines and consequently the whole farm (Bastankhah & Porté-Agel, 2019; Gebraad et al., 2015; Schepers & Van der Pijl, 2007).
Development of localization system using ultrasonic sensor for an underwater robot to survey narrow environment
Published in Journal of Nuclear Science and Technology, 2018
Ryosuke Kobayashi, Naoyuki Kono
Figure 2 shows the concept of the proposed localization method. A robot position is defined using six components (x, y, z, θRoll, θPitch, θYaw). x, y, z are the horizontal and vertical positions, and θRoll, θPitch, θYaw are the rotation angles around x, y, and z-axes, respectively. Among these parameters, the vertical position z and tilt angle (θRoll, θPitch) are directly detected by a depth sensor and a tiltmeter, respectively. The yaw angle θYaw is also detected by an angular velocity sensor. However, we need to calculate the horizontal position (x, y) by using various sensor data. The method assumes that an underwater robot has an angular velocity sensor, depth sensor, tiltmeter, structural shape-measurement sensor, and optical camera. The 3D environmental map data are built using 3D design data or previously measured data of the target environment. In the environmental information measurement, the structural shape is measured by an ultrasonic sensor. In environmental map generation, environmental maps are generated from the depth measured by the depth sensor and the tilt angle measured by the tiltmeter. Matching point is calculated between the generated environmental maps and the measured structural shape in the map-matching. Finally, the calculated matching point is converted to the robot position. The detailed calculation procedures shown in Figure 2 are as follows.
Geometric control of quadrotor with finite-time convergence and improved transients
Published in International Journal of Systems Science, 2021
The control input torque τ is generated by the thrust produced from the rotors. The rotors 1 and 3 rotate in anticlockwise direction, while rotors 2 and 4 rotate in clockwise direction. Since , increasing angular velocity of rotor 2 and decreasing that of 4 produces roll motion. Similarly, increasing angular velocity of rotor 3 and decreasing that of 1 produces pitch motion. The yaw motion is produced due to the reactive torque exerted on the frame of the body by the propeller in accordance with Newton's Third Law of Motion. Since reactive torque , yaw motion is produced if angular velocity of rotors 2, 4 is increased while that of rotors 1, 3 is decreased by same amount.