Ⅳ Analysis of UAV system Multi Rotor Brain- Flight Controller First of all, the flight controller acts as a special mixer for the multi rotor. The rise and fall of the remote controller's roll is converted to the size of the power output of the corresponding motor. In addition, now the flight controller has electric gyroscope, accelerometer, compass, barometer sensor. In the attitude mode, the attitude of the aircraft is analyzed by software algorithm. The correction of the attitude anomalies caused by the installation of the aircraft, the interference of the outside as well as the inconsistency between the components helps to maintain the stable state. Multi Rotor Power- Motor Now the mostly used motor of the multi rotor is an external rotor brush-less motor. Brush-less motor removes the brush, so the most direct change is that there is no electric Spark when the brush motor runs. This greatly reduces the interference of the electric Spark to the remote control equipment. Multi Rotor Power- ESC The electrical input is DC, which can be connected to a voltage regulator or a lithium battery. The general power supply is around the 2-6 section of lithium battery. The output is a three-phase pulse DC, which is directly connected with the three-phase input of the motor. If the electric motor is turned on and the motor reverses, it is only necessary to change any of the two positions between the three lines. There is also a signal line, which is used to connect flight controller or receiver to receive the control signal, so as to change the output current and control the running speed of the motor. Multi Rotor Power- Positive and Negative Propellers The counter torsion is caused by the air resistance when the propeller rotates. According principle of mutual effect of the force, the counter torsion will drive the aircraft to rotate in the opposite direction of the propeller rotation. In order to counteract the reverse torque of the propeller, the four propellers nearby are different in the direction of the propeller rotation, so the positive and negative propellers are needed. The wind of the positive and negative propellers all blow down. A positive propeller rotates clockwise and a negative propeller rotates counterclockwise. When the normal quad axis flights, the four propellers counteracts each other. The principle of counter torsion is applied in multi rotor rotation Multi Rotor Drone Frame The frame is the body part of the multi rotor. The materials are usually made of nylon, plastic, aluminum alloy, glass fiber and carbon fiber. Carbon fiber is the most excellent composite material with high strength and rigidity, and it is the most widely used in the production of multi rotor drone frame. Multi Rotor Power Source-Lithium Polymer Battery At present, the most commonly used battery for multi rotor is lithium polymer battery. The nominal voltage of the monolithic core is 3.7V, which is 4.2V after full charge. The lowest discharge can not be less than 3V, otherwise, the core will cause permanent damage and cannot be repaired. The battery has the characteristics of slow charging (small charging current), fast discharge (high discharge current), and it's needed to use the specific charger. Multi Rotor Ground Command Station-Remote Controller Remote controller: it is a radio communication device, composed of RC transmitter and RC receiver. The RC transmitter is hand-held and RC receiver is an airborne terminal. It's needed to send control command to the RC receiver on the drone so as to achieve the wireless control of the drone.
