Vehicle power steering system

Patent metadata

Field	Value
Publication number	US-10994772-B2
Application number	US-201916702912-A
Country	US
Kind code	B2
Filing date	Dec 4, 2019
Priority date	Dec 7, 2018
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A steering system in a vehicle includes a plurality of subsystems provided with a control unit. The control unit includes a storage unit storing steer angle information regarding a steer angle of one of a steering mechanism and a steered mechanism when the steering mechanism or the steered mechanism stops, an abnormality determiner determining abnormality of the motor rotation detection value and the detection circuit in the plurality of subsystems at a start time of a motor based on a comparison of at least two parameters, and a steer angle calculator calculating the steer angle based on the parameters having been determined by the abnormality determiner as not abnormal.

First claim

What is claimed is:

1. A steering system of a vehicle, comprising:
a steering mechanism;
a steered mechanism;
a motor configured to drive at least one of the steering mechanism or the steered mechanism; and
a control unit configured to control the motor, wherein
a plurality of subsystems provided in the steering system each include (i) a detection circuit configured to calculate a rotation detection value of the motor based on an angle sensor detecting a rotation of the motor and (ii) a power supply path configured to supply electric power from a power source to the detection circuit, and wherein
the control unit includes:
a storage unit configured to store steer angle information regarding a steering angle of the steering mechanism and/or a turning angle of the steered mechanism driven by the motor when the steering mechanism and the steered mechanism stop;
an abnormality determiner configured to determine, at a start time of the motor operation, abnormality of the rotation detection value and the detection circuit in the plurality of subsystems based on a comparison of at least two parameters among parameters including (i) a plurality of the rotation detection values respectively obtained from the detection circuits in the plurality of subsystems and (ii) the steer angle information stored in the storage unit, the at least two parameters subject to comparison respectively being a parameter obtained by using a supply of electric power from a different power supply path; and
a steer angle calculator configured to calculate the steer angle based on the parameters having been determined by the abnormality determiner as not having abnormality among the parameters including the plurality of rotation detection values and the steer angle information stored in the storage unit.

2. The steering system of claim 1 , wherein
the steering angle calculator calculates the steering angle by prioritizing the plurality of rotation detection values rather than the steer angle information.

3. The steering system of claim 1 , wherein
the plurality of subsystems each include a subsystem-specific control unit that receives a supply of the electric power from the power source provided in a subject subsystem,
the detection circuit in the subject subsystem receives a supply of electric power from the power source via the power supply path provided in the subject subsystem,
the storage unit stores, as the steer angle information, the rotation detection value obtained from the detection circuit in the subject subsystem at a stop time of the steering mechanism and the steered mechanism, and
when the rotation detection value of one subsystem and the steer angle information of an other subsystem are compared and a difference therebetween is equal to or greater than a first threshold value at the start time of the motor, the abnormality determiner determines that the detection circuit and the rotation detection value of the subsystem from which the rotation detection value is obtained are abnormal.

4. The steering system of claim 1 , wherein
the plurality of subsystems each include a subsystem-specific, individual control unit that receives a supply of the electric power from the power source provided in a subject subsystem,
the detection circuit in the subject subsystem receives a supply of electric power from the power source provided in the subject subsystem via one power supply path and from the power source provided in an other subsystem via a different power supply path,
the storage unit stores, as the steer angle information, the rotation detection value obtained from the detection circuit in the subject subsystem at a stop time of the steering mechanism and the steered mechanism, and
when the rotation detection value of the target subsystem and the steer angle information of the other subsystem are compared and a difference therebetween is equal to or greater than a second threshold value at the start time of the motor, the abnormality determiner determines that the detection circuit and the rotation detection value of the subsystem from which the rotation detection value is obtained are abnormal.

5. The steering system of claim 1 , wherein
the steering system includes a steering angle sensor capable of detecting the steering angle of at least one of the steering mechanism and the steered mechanism that is driven by the motor,
the plurality of subsystems each include a subsystem-specific, individual control unit,
the steering angle sensor receives a supply of electric power via a power supply path that is different from the power supply path of at least one of the detection circuit and the individual control unit,
the storage unit stores, as the steer angle information, a steering angle detection value detected by the steering angle sensor at a stop time of the steering mechanism and the steered mechanism, and
based on a comparison of at least two parameters from among parameters including the rotation detection value, the steer angle information, and the steer angle detection value obtained from the steer angle sensor at the start time of the motor, the at least two parameters each having been obtained by receiving a supply of the electric power from different electric power supply path, the abnormality determiner determines the abnormality of each parameter.

6. The steering system of claim 1 , wherein
the plurality of subsystems each include a plurality of angle sensors including a main sensor and a sub sensor, and
the abnormality determiner determines that at least one of the main sensor and the sub sensor is abnormal when a difference between the rotation detection value of the main sensor and the rotation detection value of the sub sensor exceeds a preset fifth threshold value.

7. The steering system of claim 1 , wherein
the control unit sets an initial position of the steering mechanism for a straight travel of the vehicle as a neutral position of the steering mechanism when the parameter for a calculation of the steering angle of the steering mechanism is determined as abnormal by the abnormality determiner.

8. The steering system of claim 1 , wherein
the control unit notifies a neutral position setting of the steered mechanism or performs the neutral position setting of the steered mechanism when the parameter for a calculation of the steer angle of the steered mechanism is determined as abnormal by the abnormality determiner.

Assignees

• Denso Corp

Inventors

• Suzuki Takashi
• Kuramitsu Shuji
• Nakajima Nobuyori
• Endoh Go
• Suzuki Haruo
• Nakamura Koichi
• Ogi Yosuke
• Oka Atsuko

Classifications

• B62D5/0484 Primary

  for reaction to failures, e.g. limp home · CPC title

• H02P29/024

  Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load · CPC title

• B62D5/0412

  the axes of motor and steering column being parallel · CPC title

• B62D15/0215

  by measuring on the steering column · CPC title

• B62D5/0487 Primary

  detecting motor faults (B62D5/0496 takes precedence) · CPC title