Rotation angle detection method and device thereof

A rotation angle detection method, applied to a rotating mechanism comprising a motor shaft, a transmission part, and an output shaft, an output torque of the motor shaft acting on the output shaft through the transmission part, and driving the output shaft to rotate, wherein a first angle sensor is arranged on the motor shaft of the rotating mechanism for detecting a first rotation angle of the motor shaft, a second angle sensor is arranged on the output shaft of the rotating mechanism for detecting a second rotation angle of the output shaft;

• the method comprising:
• calculating an estimated value of a rotation angle of the motor shaft during rotation according to the second rotation angle;
• determining an actual range of the rotation angle of the motor shaft, according to the estimated value of the rotation angle and a detection error of the second angle sensor;
• determining optional values of the rotation angle of the motor shaft, based on a relative relationship between the first rotation angle and the estimated value of the rotation angle;
• and
• determining an actual rotation angle of the motor shaft, based on a value falling within the actual range of the rotation angle of the motor shaft among the optional values of the rotation angle, and determining an actual rotation angle of the output shaft according to the actual rotation angle of the motor shaft;
• wherein before the step of calculating the estimated value of the rotation angle of the motor shaft during rotation according to the second rotation angle, further comprises:
• calculating a rotation angle corresponding relationship between the motor shaft and the output shaft, according to a transmission ratio of the transmission part;
• determining an estimated rotation number of the motor shaft, based on the second rotation angle and the rotation angle corresponding relationship between the motor shaft and the output shaft;
• and
• determining an estimated value of a real-time rotation angle of the motor shaft, based on the second rotation angle and the rotation angle corresponding relationship between the motor shaft and the output shaft;
• and
• wherein the step of calculating the estimated value of the rotation angle of the motor shaft during rotation according to the second rotation angle comprises:
• determining the estimated value of the rotation angle by adding a product of the estimated rotation number and 360° to a product of the estimated value of the real-time rotation angle and the transmission ratio.