Electric power steering apparatus

摘要

An electric power steering apparatus includes a first torque calculating unit for calculating a first torque command based on a steering torque detected by the steering torque detecting unit, a second torque command calculating unit for calculating a second torque command based on the wheel rotation speed, an emergency switching unit for outputting the second torque command instead of the first torque command when error of the rotation torque is detected, a wheel rotation speed error detecting unit for detecting an error of the wheel rotation speed based at least on the wheel rotation speed, the steering torque in a normal state and the motor rotation information, and an emergency command limiting unit for liming the second torque command when normal and the motor rotation information, and where error of the wheel rotation speed is detected, when the second torque command is selected by the emergency switching unit.

主权项

1. An electric power steering apparatus comprising:
a steering torque detecting unit configured to detect a steering torque input to a steering mechanism; a first torque command calculating unit configured to calculate a first torque command based on the steering torque detected by the steering torque detecting unit; an electric motor configured to generate a steering assist torque to be supplied to the steering mechanism; a torque detecting unit error detecting unit configured to detect error of the steering torque detecting unit; a wheel rotation speed detecting unit configured to detect a wheel rotation speed of a vehicle; a motor rotation information detecting unit configured to detect motor rotation information of the electric motor; a second torque command calculating unit configured to calculate a second torque command based on the wheel rotation speed detected by the wheel rotation speed detecting unit; an emergency switching unit configured to select the first torque command, when an error of the torque detecting unit is not detected by the torque detecting unit error detecting unit, and configured to select the second torque command, when an error of the torque detecting unit is detected by the torque detecting unit error detecting unit; a motor control unit configured to drive control the electric motor based on the torque command selected by the emergency switching unit; a wheel rotation speed error detecting unit configured to detect an error of the wheel rotation speed based on at least one of the wheel rotation speed detected by the wheel rotation speed detecting unit, the steering torque detected when the steering torque detecting unit is normal, and the motor rotation information detected by the motor rotation information detecting unit; and an emergency command limiting unit configured to limit the second torque command when the second torque command is selected by the emergency switching unit, where the error of the wheel rotation speed is detected by the wheel rotation speed error detecting unit, wherein
where the error of the wheel rotation speed is detected when the second torque command is selected, the emergency command limiting unit limits the second torque command to a limiting value calculated as a function of a deviation between a threshold and a left and right wheel rotation speed difference detected by the wheel rotation speed detecting unit.