| 摘要 |
PROBLEM TO BE SOLVED: To obtain an electric power steering for automobile for maintaining operation feeling without any feeling of wrongness even if failure such as voltage drop and instantaneous interruption occurs in the drive power supply of a torque sensor. SOLUTION: By detecting the failure in a power supply V1 of a torque sensor 108 by the self-off function of a voltage-monitoring circuit 3 or a fail switch 2, the gain of an auxiliary steering force operation means 1 is gradually decreased and a torque command Ts to an electric motor for giving auxiliary steering force to an auxiliary steering device is gradually decreased. As a result, even if the power supply V1 fails while the auxiliary steering force is in operation, the auxiliary steering force cannot be lost immediately. Since the auxiliary steering force is gradually attenuated, a driver can continue stable handle operation without any feeling of wrongness where a steering handle suddenly becomes heavy. |
