Electric Power Steering Apparatus
First Claim
1. An electric power steering apparatus comprising:
- a steering torque detecting unit for detecting a steering torque input to a steering mechanism;
a first torque command calculating unit for calculating a first torque command based on the steering torque detected by the steering torque detecting unit;
an electric motor for generating a steering assist torque to be supplied o the steering mechanism;
a torque detecting unit error detecting unit for detecting error of the steering torque detecting unit;
a wheel rotation speed detecting unit for detecting a wheel rotation speed of a vehicle;
a motor rotation information detecting unit for detecting motor rotation information of the electric motor;
a second torque command calculating unit for calculating a second torque command based on the wheel rotation speed detected by the wheel rotation speed detecting unit;
an emergency switching unit for selecting the first torque command, when an error of the torque detecting unit is not detected by the torque detecting unit error detecting unit, and for selecting the second torque command calculating unit, when an error of the torque detecting unit is detected by the torque detecting unit error detecting unit;
a motor control unit for drive controlling the electric motor based on the torque command selected by the emergency switching unit;
a wheel rotation speed error detecting unit for detecting 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 for limiting 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.
1 Assignment
0 Petitions
Accused Products
Abstract
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.
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Citations
22 Claims
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1. An electric power steering apparatus comprising:
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a steering torque detecting unit for detecting a steering torque input to a steering mechanism; a first torque command calculating unit for calculating a first torque command based on the steering torque detected by the steering torque detecting unit; an electric motor for generating a steering assist torque to be supplied o the steering mechanism; a torque detecting unit error detecting unit for detecting error of the steering torque detecting unit; a wheel rotation speed detecting unit for detecting a wheel rotation speed of a vehicle; a motor rotation information detecting unit for detecting motor rotation information of the electric motor; a second torque command calculating unit for calculating a second torque command based on the wheel rotation speed detected by the wheel rotation speed detecting unit; an emergency switching unit for selecting the first torque command, when an error of the torque detecting unit is not detected by the torque detecting unit error detecting unit, and for selecting the second torque command calculating unit, when an error of the torque detecting unit is detected by the torque detecting unit error detecting unit; a motor control unit for drive controlling the electric motor based on the torque command selected by the emergency switching unit; a wheel rotation speed error detecting unit for detecting 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 for limiting 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. - View Dependent Claims (2, 3, 4, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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5. An electric power steering apparatus comprising:
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a steering torque detecting unit for detecting a steering torque input to a steering mechanism; a first torque command calculating unit for calculating a first torque command based on the steering torque detected by the steering torque detecting unit; an electric motor for generating a steering assist torque to be supplied o the steering mechanism; a torque detecting unit error detecting unit for detecting error of the steering torque detecting unit; a wheel rotation speed detecting unit for detecting a wheel rotation speed of a vehicle; a motor rotation information detecting unit for detecting motor rotation information of the electric motor; a second torque command calculating unit for calculating a second torque command based on the wheel rotation speed detected by the wheel rotation speed detecting unit; an emergency switching unit for selecting the first torque command, when an error of the torque detecting unit is not detected by the torque detecting unit error detecting unit, and for selecting the second torque command calculating unit, when an error of the torque detecting unit is detected by the torque detecting unit error detecting unit; a motor control unit for drive controlling the electric motor based on the torque command selected by the emergency switching unit; a wheel rotation speed error detecting unit for detecting 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 for limiting 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 the second torque command calculating unit comprises a self-aligning torque estimating unit for estimating a self-aligning torque transmitted from a road surface side to the steering mechanism based on the wheel rotation speed, and a gain adjusting unit for calculating the second torque command by multiplying gain with the self-aligning torque estimated by the self aligning torque estimating unit. - View Dependent Claims (6, 7)
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8. An electric power steering apparatus comprising:
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a steering torque detecting unit for detecting a steering torque input to a steering mechanism; a first torque command calculating unit for calculating a first torque command based on the steering torque detected by the steering torque detecting unit; an electric motor for generating a steering assist torque to be supplied to the steering mechanism; a torque detecting unit error detecting unit for detecting error of the steering torque detecting unit; a wheel rotation speed detecting unit for detecting a wheel rotation speed of a vehicle; a motor rotation information detecting unit for detecting motor rotation information of the electric motor; a second torque command calculating unit for calculating a second torque command based on the wheel rotation speed detected by the wheel rotation speed detecting unit; an emergency switching unit for selecting the first torque command, when an error of the torque detecting unit is not detected by the torque detecting unit error detecting unit, and for selecting the second torque command calculating unit, when an error of the torque detecting unit is detected by the torque detecting unit error detecting unit; a motor control unit for drive controlling the electric motor based on the torque command selected by the emergency switching unit; a wheel rotation speed error detecting unit for detecting 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 for limiting 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 the second torque command calculating unit comprises a self-aligning torque estimating unit for estimating a self-aligning torque transmitted from a road surface side to the steering mechanism based on the wheel rotation speed, a gain adjusting unit for calculating the second torque command by multiplying gain with the self-aligning torque estimated by the self-aligning torque estimating unit, and a torque control unit for limiting the second torque command calculated by the gain adjusting unit on the basis at least on either of a vehicle speed calculated based on the wheel rotation speed detected by the wheel rotation speed detecting unit or a vehicle speed detected by the vehicle speed detecting unit, and a motor angular velocity calculated by the motor angular velocity calculating unit. - View Dependent Claims (9, 10)
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Specification