China
Africa
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Parachutes and Parafoils in Agricultural Crop Production
Published in K. R. Krishna, Aerial Robotics in Agriculture, 2021
Parafoil is an air drop device consisting of a non-rigid (textile) air foil with an aerodynamic cell structure. It is inflatable by wind (and used without engine or motor). It is designed to slow the descent and impact of cargo, equipment or personnel dropped from an airborne aircraft. Ram-air inflation forces the parafoil into a classic wing cross-section. Parafoils are most commonly constructed out of ripstop nylon (e.g., Parafoil ZD 141).
Fluid-structure interaction simulation for performance prediction and design optimization of parafoils
Published in Engineering Applications of Computational Fluid Mechanics, 2023
Hong Zhu, Qinglin Sun, Jin Tao, Hao Sun, Zengqiang Chen, Xianyi Zeng, Damien Soulat
The basic airfoil inlet is a crucial factor affecting the aerodynamic performance of parafoil (Cao & Zhu, 2013). To investigate the influence of airfoil shape on the aerodynamic performance of a parafoil system, we constructed two canopy models composed of airfoils with different inlet lengths, named Model C (inlet length 0.05c, c denotes the chord length) and Model D (inlet length 0.1c), respectively. For specific geometric parameters, please refer to Table 1.
In-flight wind identification and soft landing control for autonomous unmanned powered parafoils
Published in International Journal of Systems Science, 2018
Shuzhen Luo, Panlong Tan, Qinglin Sun, Wannan Wu, Haowen Luo, Zengqiang Chen
In recent years, delivery of military paratroopers and supplies to ground troops has been more and more accomplished by autonomously operating, parafoil-based aerial delivery system, which can carry the payload from mere kilos up to 10 ton. This system usually contains a ram-air parafoil that is controlled by actuators, several sensors and complementary items (Jing, 2005; Li, Yang, He, & Han, 2016; Zhang, Gao, Chen, Sun, & Zhang, 2013). The parafoil system is superior to the well-known round-canopy system for their ability to easily handle in the flight and even enable a precise and soft landing. Furthermore, the powered parafoil system is a new kind of flexible wing vehicle, which consists of the parafoil and power plant that is equipped on the back of the payload. This system extends possible applications of unpowered parafoil systems with the ability to take off from the ground and cruise for a long time, which has widespread applications in both the civil and military fields (Yakimenko, 2015). However, given the flexible fabric materials for the canopy and low flight speed, the powered parafoil system is obviously subjected to the wind disturbance (Horst, 2013; Ward, Costello, & Slegers, 2010; Watanabe & Ochi, 2008; Yakimenko, 2015; Zhu et al., 2015). If we can obtain the information of wind speed and direction, it is the key point for the system to take advantage of winds or to eliminate wind impacts. First, knowing the winds aloft ensures that the system can possibly reach the intended touch-down area. Additionally, when the powered parafoil system carry out the mission and track trajectory, a certain compensation control strategy for the known wind information can improve the tracking accuracy and the stability of the system. Second, for autonomous landing parafoil systems, the ability to perform a final flare manoeuvre against the wind direction allows a considerable reduction of horizontal and vertical velocities at impact, enabling soft landings required for a safe delivery of sensible loads. Therefore, it is crucial for the system to know the information of wind. Due to the above reasons, the wind identification in the flight process is of great significance to the development of the system.