controller signal

Hello, I have a general questions about the trajectory control of quadcopter. Suppose we have a ground station which can send the control command to quadcopter and all accurate feeback data. For a specific trajectory, by using PID, we can get a position error [x_e, y_e, z_e]', further, we can...

Hi, I recently bought a Syma X8W and I am trying to fly for the first time however it seems like one of the motor is running slower then others and Remote Control is showing the signal keep flashing. Can you please help and do you know why the signal keep flashing? I have already full charged...