Basic information on multicopter technology

Multicopters (often colloquially referred to as "drones") are based on a simple principle: At least four drive units (electric motors with propellers) arranged crosswise on one level are individually controlled by electronics. The drive units are arranged in such a way that they push the air away downwards and thus give the multicopter a thrust vertically upwards. This causes the multicopter to hover in the air. The electronics use various sensors (gyroscopes, air pressure gauges, compass) to ensure that the multicopter remains in balance and thus in the air.

Position corrections are achieved by the individual speed control of the individual motors. If the speed is slightly reduced on one drive unit, the thrust on that side is reduced and the multicopter tilts a little in that direction. This causes the multicopter to move in that direction. If the speed is changed evenly on all drive units, the multicopter will rise or fall.

Multicopters always have several pairs of drive units and are therefore also called quadrocopters, hexacopters or octocopters according to the number of motors. In each pair of drive units, the two electric motors are driven in opposite directions to neutralise the effects of the torque of the individual motors on the direction of rotation of the multicopter. However, if rotation of the multicopter is desired, for example, for a clockwise rotation, the speed is increased for all the left-turning motors, while it is decreased for the right-turning motors. This keeps the multicopter at the same altitude, but uses the torque of the motors for rotation around its own axis.

With the help of a radio remote control, the pilot influences the flight behaviour of the multicopter and thus steers the multicopter to the desired position and altitude. Current multicopters also have GPS support and a compass. This allows the multicopter to determine and control its own position and altitude. This function can be used to make the multicopter hold its position independently, even against wind influences, i.e. to "park" it at a point.

To take pictures from the air, you can attach a camera to a multicopter. If you mount the camera in a so-called "gimbal", the tilt angle can be controlled independently of the orientation of the multicopter via the radio remote control. Current gimbals automatically compensate for flight movements of the multicopter so that the camera always remains optimally aligned. The release of the camera can also be influenced via the radio remote control.

In order to check the image section of the camera, the current camera image can be tapped and transmitted via a video radio link to a ground station. Here the camera image can be displayed on a monitor or video glasses. With the help of this technical support, it is possible for the pilot to correct the alignment of the camera and to trigger the camera at the right moment.