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Unmanned Aerial System Applications to Coastal Environments
Published in David R. Green, Billy J. Gregory, Alex R. Karachok, Unmanned Aerial Remote Sensing, 2020
Francesco Mancini, Marco Dubbini
Within the rotary-wing models, helicopters and multi-rotors (quad/hexa/octocopters) are the most used for environmental applications and two-dimensional (2D)/3D mapping. One of the major advantages of rotary-wing over fixed-wing aircraft lies in the possibility to hover over a target site, acquire data, images, or video for a selected time and move towards the target for closer inspection at the preferred spatial resolution (Klemas 2015). The need for aircraft with greater manoeuverability and hovering ability has led to a rise in quadcopter use in environmental monitoring and mapping. The UAS regulations for rotary-wing aircraft differ from country to country. However, procedures to authorise UAV flights in nonexclusion areas can be issued by national aviation authorities under similar restriction rules. Vertical take-off and landing UAVs can operate within an aerial work area and under visual line-of-sight conditions (Colomina and Molima 2014). These are now widely used in coastal monitoring and wetland mapping and for flood damage assessment and coastal dynamics studies. Hexacopters and octocopters can carry consumer-grade cameras and fly for 10–20 minutes following a pre-programmed path, with or without stops, and they cost less than US$ 5,000. New systems that can carry multispectral and hyperspectral imagers are being designed, and sensors are being miniaturised to be used on board light UAVs. Due to the ease of use of these models, many of the applications discussed in this chapter have developed for multi-rotor UAV surveys. However, the piloting of multi-rotor UAVs can be problematic under windy conditions (wind speed, >20 km/h) and when there are wind gusts and thermals. Helicopters are less frequently used for coastal investigations, but their performance during a flight can be attractive. Delacourt et al. (2009) developed and tested an unmanned helicopter (DRELIO) to operate under windy conditions of up to 50 km/h and to perform stationary flights from heights up to 300 m through the use of a thermal engine.
A design modification for a quadrotor UAV: modeling, control and implementation
Published in Advanced Robotics, 2019
Sherif Badr, Omar Mehrez, A. E. Kabeel
The quadrotor or quadcopter is a unique type of unmanned aerial vehicles (UAVs) which has Vertical Take Off and Landing ability. The quadrotor has an advantage of maneuverability due to its inherent dynamic nature. Meanwhile, the small size of such UAVs is especially suitable for some applications like surveillance tasks and military purposes. Quadrotors also have potential applications in other areas like earth sciences. Vision systems could be implemented in UAVs which permit covering areas such as object detection and object tracking. Study of quadrotors has interested researchers due to their capability to perform tasks efficiently and accurately. Recently, the focus has shifted to modify the quadrotor design to overcome its existence limitations.