Analysis of the four-axis principle of Drone

The core principle of the Drone quadcopter (quadrotor) can be simply summarized as:
Through the speed difference of the four rotors, the lift and torque are controlled to achieve flight attitude adjustment.
1. Infrastructure
4 rotors: in pairs of two, rotating clockwise (CW) and counterclockwise (CCW) to counteract rotational torque.
Motor and flight controller: The motor regulates the speed to change the rotor speed, and the flight controller (including gyroscope, accelerometer, etc.) senses the attitude and controls the motor.
2. Flight control logic
VTOL:
The 4 rotors rotate at constant speed, and the total lift is > when gravity rises, vice versa, and hovers when equal.
Forward and backward / left and right movement:
For example, "forward": reducing the speed of the front rotor and increasing the speed of the rear rotor, the fuselage leans forward, and the horizontal component of lift pushes forward.
Rotation (yaw):
Increase the speed of a certain set of rotors (e.g., clockwise group), its reverse torque is greater than that of another group, and the fuselage rotates in the opposite direction (e.g., counterclockwise).
Attitude Stability:
The flight controller detects attitude deviations (such as tilt and rotation) in real time through sensors, and automatically adjusts the rotor speed correction.
3. Key takeaways
Balance of forces: Lift against gravity, torque is counteracted by forward and reverse rotating rotors.
Core logic: By changing the speed of any rotor, the balance of force or torque is broken to achieve movement or steering.
Summary: The quadcopter drone relies on the "speed difference" to play mechanical balance, and the flight controller is adjusted in real time as the "brain", so as to achieve flexible flight.