A quadcopter drone is basically controlled with 4 rotors and hence the name. These drones are called rotorcraft since the lift gets generated by 4 sets of airfoils at every corner. It comes with a couple of sets of identical pitch propellers, 2 of them move clockwise and 2 move counter clockwise. The variations in the RPM is what controls lift and throttle for quadcopters.
The motion of these copters is achieved when the RPM of one or more than one rotor is changed. This innovation is what has helped solve the problem of vertical flight and the torque induced control can also be overcome. The design allows it to cast out tail rotors, which aren't very efficient when it comes to a lift. These vehicles are the most efficient as far as vertical takeoff & landing is concerned.
These models have become so much more popular as far as UAV's are concerned. They make use of electronic control systems as well as electronic sensors which can help stabilize them. This is why they are available in a number of sizes with a constant amount of control as well as maneuverability that makes them very good a far as outdoor and indoor usage is concerned.
Here are a couple of the advantages of quadcopters:
1. They don't need any mechanical linkages which you need to do in order to make the desired angle for controlling the movement which can ultimately give a stable design as well as less maintenance for the UAV. The lesser the parts, the lesser the possibility of any faults occurring right?
2. The use of an individual rotor which results in a smaller diameter for the rotors, makes them a lot more stable and also reduces the amount of kinetic energy which is being acquired. This usually leads to less damage as far as any unwanted accidents are concerned. This is what makes this type of UAV a lot safer as far as close interaction is concerned.
Since first implemented way back in 1907 they have gone through a lot of improvisation when small scale UAV's came into the picture and are now being used in some model aircraft projects as well. The current research and advancement means that eventually these quadcopters will be able to perform autonomous advanced missions which cannot be performed by other UAV's. Recently 4K cameras have also been used with these drones and their uses have increased dramatically ever since this happened.
