Steering system for vehicle

Patent metadata

Field	Value
Publication number	US-12286168-B2
Application number	US-202118002550-A
Country	US
Kind code	B2
Filing date	Mar 31, 2021
Priority date	Mar 31, 2021
Publication date	Apr 29, 2025
Grant date	Apr 29, 2025

Abstract

In a steer-by-wire steering system for a vehicle, a control unit ( 16 ) controls an operation of a steering actuator to cause the steered angle of wheels to be in a prescribed relationship to a steering angle, and an operation of the reaction force actuator ( 15 ) including a pair of reaction force motors ( 14 ) to cause the reaction force to be a value (Tt) corresponding to a steered state of the wheels, wherein the control unit is provided with a failure detection unit ( 36 ) configured to detect failures of the reaction force motors, and upon detecting a failure of one of the reaction force motors, progressively reduce an output (Tta) of the other reaction motor to a prescribed limit value (TL).

First claim

The invention claimed is:

1. A steering system for a vehicle, comprising:
a steering member configured to receive a steering operation;
a steering mechanism mechanically separated from the steering member and configured to steer wheels;
a steering angle sensor that detects a steering angle of the steering member; a steered angle sensor that detects a steered angle of the wheels;
a steering actuator configured to provide a drive force to the steering mechanism; a reaction force actuator including at least two reaction force motors and configured to apply a reaction force to the steering member in response to the steering operation; and
a control unit that controls an operation of the steering actuator to cause the steered angle to be in a prescribed relationship to the steering angle, and an operation of the reaction force actuator to cause the reaction force to be a value corresponding to a steered state of the wheels,
wherein the control unit is provided with a failure detection unit configured to detect failures of the reaction force motors, and upon detecting a failure of all but one of the reaction force motors, progressively reduce an output of the remaining reaction force motor to a prescribed limit value,
wherein the limit value is equal to or greater than a value that allows the steering member to be driven by the reaction force actuator while no external force is applied to the steering member.

2. A steering system for a vehicle according to claim 1 , wherein the steering member includes a steering wheel that is rotatable around an axis of a steering shaft, and the limit value is smaller than a value that is required to cancel a torque corresponding to a loading of a weight of an arm of a driver placed on the steering wheel.

3. A steering system for a vehicle, comprising:
a steering member configured to receive a steering operation;
a steering mechanism mechanically separated from the steering member and configured to steer wheels;
a steering angle sensor that detects a steering angle of the steering member; a steered angle sensor that detects a steered angle of the wheels;
a steering actuator configured to provide a drive force to the steering mechanism; a reaction force actuator including at least two reaction force motors and configured to apply a reaction force to the steering member in response to the steering operation; and
a control unit that controls an operation of the steering actuator to cause the steered angle to be in a prescribed relationship to the steering angle, and an operation of the reaction force actuator to cause the reaction force to be a value corresponding to a steered state of the wheels,
wherein the control unit is provided with a failure detection unit configured to detect failures of the reaction force motors, and upon detecting a failure of all but one of the reaction force motors, progressively reduce an output of the remaining reaction force motor to a prescribed limit value,
wherein the control unit progressively reduces the output of the remaining reaction force motor at a reduction rate (R) which gets smaller as a vehicle speed increases.

4. A steering system for a vehicle, comprising:
a steering member configured to receive a steering operation;
a steering mechanism mechanically separated from the steering member and configured to steer wheels;
a steering angle sensor that detects a steering angle of the steering member; a steered angle sensor that detects a steered angle of the wheels;
a steering actuator configured to provide a drive force to the steering mechanism; a reaction force actuator including at least two reaction force motors and configured to apply a reaction force to the steering member in response to the steering operation; and
a control unit that controls an operation of the steering actuator to cause the steered angle to be in a prescribed relationship to the steering angle, and an operation of the reaction force actuator to cause the reaction force to be a value corresponding to a steered state of the wheels,
wherein the control unit is provided with a failure detection unit configured to detect failures of the reaction force motors, and upon detecting a failure of all but one of the reaction force motors, progressively reduce an output of the remaining reaction force motor to a prescribed limit value,
wherein the control unit progressively reduces the output of the remaining reaction force motor at a reduction rate which is larger when the vehicle is cornering than when the vehicle is traveling straight ahead.

5. A steering system for a vehicle, comprising:
a steering member configured to receive a steering operation;
a steering mechanism mechanically separated from the steering member and configured to steer wheels;
a steering angle sensor that detects a steering angle of the steering member; a steered angle sensor that detects a steered angle of the wheels;
a steering actuator configured to provide a drive force to the steering mechanism;
a reaction force actuator including at least two reaction force motors and configured to apply a reaction force to the steering member in response to the steering operation; and
a control unit that controls an operation of the steering actuator to cause the steered angle to be in a prescribed relationship to the steering angle, and an operation of the reaction force actuator to cause the reaction force to be a value corresponding to a steered state of the wheels,
wherein the control unit is provided with a failure detection unit configured to detect failures of the reaction force motors, and upon detecting a failure of all but one of the reaction force motors, progressively reduce an output of the remaining reaction force motor to a prescribed limit value,
wherein the control unit progressively reduces the output of the remaining reaction force motor only when an absolute value of the steering angle is larger than a predetermined value.

6. A steering system for a vehicle, comprising:
a steering member configured to receive a steering operation;
a steering mechanism mechanically separated from the steering member and configured to steer wheels;
a steering angle sensor that detects a steering angle of the steering member; a steered angle sensor that detects a steered angle of the wheels;
a steering actuator configured to provide a drive force to the steering mechanism; a reaction force actuator including at least two reaction force motors and configured to apply a reaction force to the steering member in response to the steering operation; and
a control unit that controls an operation of the steering actuator to cause the steered angle to be in a prescribed relationship to the steering angle, and an operation of the reaction force actuator to cause the reaction force to be a value corresponding to a steered state of the wheels,
wherein the control unit is provided with a failure detection unit configured to detect failures of the reaction force motors, and upon detecting a failure of all but one of the reaction force motors, progressively reduce an output of the remaining reaction force motor to a prescribed limit value,
wherein the steering system further comprises a vibration device for vibrating the steering member, wherein the control unit is configured to control the operation of the vibration device such that the vibration device is activated so as to vibrate the steering member while the vehicle is traveling straight and the output of the remaining reaction force motor is being progressively reduced.

7. A steering system for a vehicle according to claim 6 , wherein the control unit drives the vibration device only while the vehicle is traveling straight, and controls the steering actuator so as not to change the steering angle while dr

Assignees

• Honda Motor Co Ltd
• Thyssenkrupp Presta Ag

Inventors

• Ojima Yosuke
• Hanji Munetsugu
• KULCSAR David
• Szepessy Imre
• DOMBAI Laszlo
• Kakas Peter

Classifications

• B62D15/0215

  by measuring on the steering column · CPC title

• B62D6/008

  Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications · CPC title

• B62D5/0484

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

• B62D5/006

  power actuated · CPC title

• B62D5/003 Primary

  Backup systems, e.g. for manual steering (B62D5/30 takes precedence) · CPC title