Have you ever wondered how your drones fly? What is the science and physics that allows them to fly?
[/vc_column_text][vc_column_text]The drone is a quadcopter that has 4 rotors that are all connected to individual motors, allowing them to move at different speeds. The two diagonal rotors spin clockwise, while the other two diagonal motors spin counterclockwise. The two opposing rotations balance each other out and keep the drone steady. So if all the rotors were to spin in the same direction, it would result in a net torque that causes the complete quadcopter to spin. When the rotors spin together, they push down on the air and the air pushes up on the rotors. When the rotors spin fast the drone will rise into the sky and when the rotors slow down the drone will descend towards the ground.[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column width="1/5"][vc_column_text]
Diagram of the reaction torques on each motor of a quadcopter aircraft, due to the rotation of the rotors. Rotors 1 and 3 rotate in one direction, while rotors 2 and 4 rotate in the opposite direction, producing opposite torques for control.
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The red propellers move clockwise while the blue propellers move counterclockwise.
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A quadcopter hovers or adjusts its altitude by applying equal thrust to all four rotors.
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A quadcopter regulates its yaw by applying more thrust to rotors rotating in one direction.
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A quadcopter adjusts its pitch or roll by applying more thrust to one rotor and less thrust to its diametrically opposed rotor.
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Forces and moments that impact the drone
Four propellers produce thrust Fi in the direction perpendicular to the plane of rotation of the propeller. This thrust is proportional to the square of the angular velocity of the propellers. As the propellers rotate, they create the reaction torque Mi on the quadcopter about the Z-axis. This reaction torque is proportional to the square of the angle. Angular velocity of the propeller. Thrust produced by opposite torques of propeller production torque Mx and My. This torque is given by different forces x length between two propellers. And finally, the gravitational force that always acts in the downward direction. The motion of the quadcopter can be analyzed by Newton's second law of motion.
[/vc_column_text][vc_single_image image="20276" img_size="full" alignment="center"][vc_column_text]So, how do you, you may be wondering, do the Quadcopter get free in the air?
To get off the ground, the drone needs a net Upward Force. Since a quadcopter is stable in the air, it needs to be in balance. The drone's motors generate a thrust greater than the quadcopter's weight, causing the quadcopter to rise upwards. All forces need to be balanced and the total thrust F1 + F2 + F3 + F4 produced by the propeller must equal the quadcopter's weight and all the torque produced must equal 0.
The governing equation for this motion is “All Moments = 0”. The motors generate thrust. In the case of increasing motion, the net thrust produced by all the propellers is greater than the weight of the quadcopter. This results in an out-of-motion of the quadcopter, which in this case is mr> 0. For the falling motion, the thrust produced by all the propellers must be less than the weight of the quadcopter.[/vc_column_text][vc_single_image image="20275" img_size="full" alignment="center"][vc_column_text]
Conclusion
Now that we have gotten through all the physics of drones, you will have probably noticed that every movement is accomplished by changing the rotation speed of one or more rotors on the drone. This can be done by the remote controller which does this by increasing or decreasing the voltage of each motor. But as you already know if you have ever flown a quad bike we don’t do this for each motor individually because it would be insanely difficult to manually adjust. However, if you have a control system like an accelerometer and gyroscope you can simply press a joystick with your thumb and let a computer handle all of that. An accelerometer and gyroscope in the drone can further increase the ease and stability of flight by making minute adjustments to the power of each rotor. Add in a GPS system and you can pretty much eliminate the human entirely. So you can see that flying a drone is quite easy if you let the computer do all the work. But it is still nice to understand the physics behind it.
