Hello, i am newbie in quadcopter.
I have looked on some research paper by google.
Most of those paper mention the PID controller to maintain the motor's speed in order to maintain stability.
My 1st question is: does PID controller is a must to maintain quadcopter's stability?
if yes, why simple PWM to control motor is not enough?
2nd question: most of the board kit available on sale provide accelerometer to measure the pitch, roll and, yaw. Does measuring those parameters related with PID?
I hope someone could enlighten me.
Thank you for you attention.