Patent ID: 7827001

Claim:
A method for fault detection in an actuator ( 2 ), the method comprising the steps of: generating a control value ( 1 ) via a control unit ( 11 ); transmitting the control value ( 1 ) to both an actuator ( 2 ) and a modeling unit ( 3 ); sensing a measured actuator position ( 4 ) with a sensor with the measured actuator position ( 4 ) being relative to the control value ( 1 ); sending the measured actuator position ( 4 ), sensed by the sensor, to a signal conditioning unit ( 5 ) which determines a measured actuator movement ( 6 ) from the measured actuator position ( 4 ) over a defined time interval; calculating, in the modeling unit ( 3 ), an expected actuator movement ( 7 ) based solely upon the control value ( 1 ) which is the only input to the modeling unit ( 3 ) over the defined time interval; sending both the measured actuator movement ( 6 ), from the conditioning unit ( 5 ), and the expected actuator movement ( 7 ), from the modeling unit ( 3 ) to a computer unit ( 8 ) such that by summing the measured actuator movement ( 6 ) and the expected actuator movement ( 7 ) over the defined time interval between 10 and 20 calculation cycles, a drifting separation of the measured actuator movement ( 6 ) from the expected actuator movement ( 7 ) is minimized; and producing at an output, via the computer unit ( 8 ), corresponding status signal ( 9 ) concerning a functioning status of at least one of the actuator ( 2 ) and the sensor for determining the actuator position ( 4 ).