Quadcopters are robots which use their four rotors to fly. Different control of four motors of their rotary wings helps the robot implement various maneuvers. Quadcopters are quite agile flying robots. Historically they gained high interest due to their vertical lift off ability, but because of their inefficiency development of these robots slowed down. With the introduction of unmanned aerial vehicles and the advances in the robotic technology, they gained popularity mainly among researchers and hobbyists. Due to their small size and high maneuverability, they are suitable both for indoor and outdoor usage. For that reason researchers and hobbyists show high interest for these flying robots.
Quadcopters are used for various purposes because they are much easier to produce. Besides commercial quadcopters that are intended for hobbyists, these robots are used by the researchers for developing or testing flight control techniques. They are used in recon and safety missions with military purposes. The main disadvantages of quadcopters are their low lifting capacity and short flying times.