FAILURE DETECTOR FOR STEERING TORQUE DETECTING MEANS

摘要

PROBLEM TO BE SOLVED: To surely detect a failure in a steering torque sensor irrespective of fluctuation in a power source voltage. SOLUTION: The failure detection in the steering torque sensor is allowed when the power source voltage for supplying electric power to the steering torque sensor of a motor-driven power steering device exceeds an operation voltage lower limit value (referring to an area A), and the failure detection in the steering torque sensor is prohibited when the power source voltage comes to the operation voltage lower limit value or less (referring to an area B). The failure detection in the steering torque sensor is left under the prohibited condition until the lapse of a prescribed time is confirmed by a restoration counter, even when the power source voltage is restored thereafter to exceed the operation voltage lower limit value (referring to an area C), and the failure detection in the steering torque sensor is allowed after the lapse of the prescribed time (referring to an area A'). Erroneous detection is thereby prevented from being generated caused by executing the failure detection in the steering torque sensor under an unstable condition just after the restoration to the normal power source voltage. COPYRIGHT: (C)2005,JPO&NCIPI