Patent ID: 7190138
Filing Date: 2007-03-13
Classification: F16H,H02P

Abstract:
1. A motor drive control system failure monitoring apparatus designed to monitor a failure in operation of a motor drive control system which controls rotation of a motor working to output torque to a motor-driven member through a torque transmitting mechanism and an output shaft joined to the motor-driven member and includes a motor angular position sensor working to produce an output as a function of an angular position of the motor for use in controlling rotation of the motor to bring the angular position of the motor into agreement with a target one and an output shaft angular position sensor working to produce an output as a function of an angular position of the output shaft, said failure monitoring apparatus comprising: a first comparing circuit working to compare one of the output of the motor angular position sensor and a change in the output of the motor angular position sensor with one of the output of the output shaft angular position sensor and a change in the output of the output shaft angular position sensor; a second comparing circuit working when the motor is at rest to compare the output of the motor angular position sensor with the target angular position when the motor is at rest; and a failure diagnosing circuit working to discriminate among failures in operation of the motor angular position sensor and the output shaft angular position sensor and another type of failure using results of the comparisons as made by said first and second comparing circuits; wherein when the result of comparison made by said first comparing circuit shows that the one of the output of the motor angular position sensor and the change in the output of the motor angular position sensor mismatches the one of the output of the output shaft angular position sensor and the change in the output of the output shaft angular position sensor, said failure diagnosing circuit discriminates between the failures in operation of the motor angular position sensor and the output shaft angular position sensor based on whether the result of comparison made by the second comparing circuit shows a match between the output of the motor angular position sensor and the target angular position or not, and wherein when the result of comparison made by said first comparing circuit shows that the one of the output of the motor angular position sensor and the change in the output of the motor angular position sensor matches the one of the output of the output shaft angular position sensor and the change in the output of the output shaft angular position sensor, said failure diagnosing circuit discriminates between the failures in operation of the motor angular position sensor and the output shaft angular position sensor based on whether the result of comparison made by the second comparing circuit shows a mismatch between the output of the motor angular position sensor and the target angular position or not.