Development and Testing of a Control System for the Automatic Flight of Tethered Parafoils

Coleman, Joseph; Ahmad, Hammad; Toal, Daniel

doi:10.1002/rob.21652

Cited by 5 publications

(3 citation statements)

References 23 publications

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“…The challenges to attach reliable instrumentation to the canopy fabric make in-flight experimental measurements either impossible or extremely difficult [6]. While recent efforts focusing on control and guidance have successfully used in-canopy motion sensors [9,10,12,26], the in-flight measurement of the airfoil aerodynamic characteristics remains a challenge. None of these works, however, attempted to use outer-inner local pressure-differential analysis as an alternative to the classic external pressure coef-ficient assessments.…”

Section: Structural Aspectsmentioning

confidence: 99%

Wind-Tunnel Measurement of Differential Pressure on the Surface of a Dynamically Inflatable Wing Cell

Benedetti

Veras

2021

Aerospace

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An instrumentation system for in-situ measurement of the inner-outer pressure differential at the upper and lower surfaces of dynamically inflatable wings is designed and tested, revealing important insights into the aerodynamic characteristics of inflatable airfoils. Wind tunnel tests demonstrated full capability of low-pressure differential readings in the range of 1.0–120 Pa, covering speeds from 3 to 10 m/s at angles of attack from −20 to +25°. Readings were stable, presenting coefficients of variation from 2% to 7% over the operational flight envelope. The experimental data confirmed the occurrence of a bottom leading-edge recirculation bubble, linked to the low Reynolds regime and the presence of an air intake. It supported the proposition of a novel approach to aerodynamic characterization based on local pressure differentials, which takes in account the confined airflow structure and provides lift forces estimations compatible with practical observation. The results were also compatible with data previously obtained following different strategies and were shown to be effective for parameterizing the inflation and stall phenomena. Overall, the instrumentation may be applied straightforwardly as a flight-test equipment, and it can be further converted into collapse alert and prevention systems.

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Section: Structural Aspectsmentioning

confidence: 99%

Wind-Tunnel Measurement of Differential Pressure on the Surface of a Dynamically Inflatable Wing Cell

Benedetti

Veras

2021

Aerospace

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“…The non-reversing pumping-mode AWE system employing a kite or a glider for harnessing the wind energy is the focus of this paper [5]. Non-reversing pumping mode AWE systems have been initially developed at the University of Limerick, Ireland [5][6][7]. In this type of pumping mode AWE system, a kite or glider is tethered to a ground station consisting of a tether drum coupled to a generator and a fractional scale recovery motor.…”

Section: Introductionmentioning

confidence: 99%

Power Control of Direct Interconnection Technique for Airborne Wind Energy Systems

2018

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In this paper, an offshore airborne wind energy (AWE) farm consisting of three non-reversing pumping mode AWE systems is modelled and simulated. The AWE systems employ permanent magnet synchronous generators (PMSG). A direct interconnection technique is developed and implemented for AWE systems. This method is a new approach invented for interconnecting offshore wind turbines with the least number of required offshore-based power electronic converters. The direct interconnection technique can be beneficial in improving the economy and reliability of marine airborne wind energy systems. The performance and interactions of the directly interconnected generators inside the energy farm internal power grid are investigated. The results of the study conducted in this paper, show the directly interconnected AWE systems can exhibit a poor load balance and significant reactive power exchange which must be addressed. Power control strategies for controlling the active and reactive power of the AWE farm are designed, implemented, and promising results are discussed in this paper.Energies 2018, 11, 3134 2 of 17 they reverse the generator for use as a motor for the recovery process. Reversing the generator in the conventional pumping mode procedure creates difficulty for utility-scale grid interconnection due to the inefficiencies of stopping a large generator and reversing the system as a motor [5]. A variation on the concept of using a separate motor and generator for the recovery phase and power phase are considered by the researchers at TU Delft [8]. The non-reversing pumping mode AWE system is illustrated in Figure 1 (see [5] for greater detail).Compared to the conventional wind turbines, the need for less mechanical and civil construction has made AWE systems an ideal technology for floating offshore wind energy systems where the size of offshore construction is significantly critical [8][9][10]. A factor which is more important when reported studies show increasing attention to the offshore wind resources due to higher wind energy availability, less environmental effects and less land limitation in comparison with on-land wind energy systems [11,12]. For instance, the potential of Ireland for the installation of offshore and on-land wind energy systems by 2050 is 30 GW and 11-16 GW, respectively [13], almost double the capacity for offshore wind compared to on-land wind. Furthermore, the Irish maritime area is ten times larger than the country's landmass providing an exceptional land area for the installation of floating wind energy systems [14].The direct interconnection technique is a new approach to improve the cost and availability of offshore wind energy systems. Pican et al. first introduced the direct interconnection technique (DIT) in 2011 for conventional offshore wind turbines [15,16]. In this technique, unlike the conventional approach, all the offshore units are directly interconnected to each other without any power electronic converter. After dispatching the generated power to shore, the farm power is con...

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“…23 All these small-scale infrastructures involve sensor fusion setups and algorithms mostly targeted (but not limited) to the dynamic characterization and closed-loop control design of AWE systems. [24][25][26][27][28][29] Most of them included onboard equipment like an inertial measurement unit (IMU), global navigation satellite system (GNSS) receivers, load cells, and line angle sensors, among others. It was demonstrated that line angle sensors jeopardized the estimations due to tether sagging and tether dynamics when compared with range sensors.…”

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confidence: 99%

Automatic testbed with a visual motion tracking system for airborne wind energy applications

et al. 2023

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The architecture and a flight test campaign of a small‐scale testbed aimed at aerodynamic and dynamic characterization of airborne wind energy systems are presented. The testbed involves a two‐line rigid‐framed delta kite and an automatic ground station for the lateral control of the kite and reel‐in/reel‐out of the two tethers. The environment, and the states of the kite, the tethers and the actuators are measured by a set of on‐ground and onboard sensors that include, among others, an inertial measurement unit, GNSS receivers, load cells, actuator encoders, a wind station, and a visual motion tracking (VMT) system based on three cameras and an artificial neural network (YOLOv2). The results of a 5‐min flight, including the take‐off, cross‐wind flight, and landing, were used to analyze the capabilities of the testbed. It was shown that the time derivative of the kite course angle exhibits a linear correlation with both the delayed steering input and the delayed differential tether tension, being the dispersion lower for the latter. The intrinsic and extrinsic calibrations proposed for the VMT system led to a good agreement between the estimation of the kite position and course angle provided by the VMT system and the onboard computer. Moreover, although the YOLOv2 algorithm failed in the detection of the kite within around 5% of the images, the simultaneous non‐detection from the three cameras was below 0.1% during the full flight. Such a reliability suggests that a VMT system can be used as a redundant or backup sensor for the GNSS.

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Development and Testing of a Control System for the Automatic Flight of Tethered Parafoils

Cited by 5 publications

References 23 publications

Wind-Tunnel Measurement of Differential Pressure on the Surface of a Dynamically Inflatable Wing Cell

Wind-Tunnel Measurement of Differential Pressure on the Surface of a Dynamically Inflatable Wing Cell

Power Control of Direct Interconnection Technique for Airborne Wind Energy Systems

Automatic testbed with a visual motion tracking system for airborne wind energy applications

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