Quadcopter Drones and Unmanned Aerial Vehicles
What is a quadcopter?
A quadcopter drone is an unmanned aerial vehicle with two pairs of rotors that are used to generate lift to enable the aircraft to fly. One pair of rotors turns clockwise and the other anti-clockwise, and by varying the speeds it is possible to generate thrust as well as turning motions.
Quadcopters are simpler in construction and cheaper and easier to fly than manned helicopters, making them an ideal choice for certain applications such as surveying and aerial photography. Their ability to hover in place gives them an advantage over fixed-wing UAVs and aircraft for small-scale surveillance and reconnaissance. They can also be used for deliveries, and have already been used to provide medical supplies in both remote and urban areas.
Many quadcopters are gyro-stabilised to allow them to fly smoothly even under windy conditions. An IMU (inertial measurement unit) detects changes in the yaw, pitch and roll of the aircraft and sends data to a flight controller, which adjusts the output to the rotors to achieve the desired outcome.
Quadcopter drone size and endurance
Quadcopter sizes range from mini quadcopters not much more than an inch square, to professional UAV systems measuring two to three feet in diameter. There tends to be an upper limit on the size of quadcopters as more volume means more weight, which requires more power to lift – there is then a tradeoff between battery weight and size versus flight endurance.
The typical flight time of a battery-powered quadcopter is around 30 minutes. New designs have managed to extend this by incorporating battery cells into a majority of the quadcopter structure. Hydrogen fuel cells, providing a greater energy density than batteries, can also be affixed to larger quadcopters to extend flight endurance.
Quadcopter cameras and aerial imaging
Aerial imaging is the most popular application for quadcopter UAVs, and many manufacturers offer packages pairing a quadcopter with camera payload. These cameras may be integrated into multi-axis gimbals that allow the camera to be moved during flight and also reduce the effects of vibration.
Quadcopter video and still image camera payloads can offer powerful optical and digital zoom capabilities, with 4K video and still image resolutions in the tens of megapixels, making them ideal for tactical and professional applications such as surveillance and industrial inspection. Some quadcopter cameras also offer FPV (First Person View) capabilities, in which low-latency video is fed back to the pilot via 4G/LTE to a screen or headset. FPV drones are often used in the sport of quadcopter racing.
Many quadcopter imaging systems feature a range of intelligent flight modes to enhance functionality, such as following the operator, active target tracking, and autonomous following of waypoints.