Patent ID: 9574876
Date: 2017-02-21
CPC Classifications: G01C,G01D

Claim:
1. An angle detector for detecting an operation angle of an electric actuator having an electric motor, the electric motor configured to generate rotation force when being energized, the angle detector comprising: a controller, including a computer processor, the controller being at least configured to: a mechanical stopper attached to the electric actuator to provide a mechanical rotational limitation of the electric actuator; wherein except when a first condition or a second condition is satisfied, the controller calculates the first average current by using the sampled motor current flowing through the electric motor during operation of the electric actuator and by accumulating the sampled motor current, the first condition is satisfied when a derivation of the motor current with respect to time is equal to or greater than a first threshold value, the second condition is satisfied when a value, which is calculated by subtracting a previous sampled motor current from a present sampled motor current, is equal to or greater than a second threshold value, when the first condition or the second condition is satisfied, the controller calculates the first average current by adding a rotor-locked current instead of the sampled motor current, and the rotor-locked current flows though the electric motor when the electric actuator abuts on the mechanical stopper and cannot mechanically operate.