Method and arrangement for an electrical steering system

• US 9,555,824 B2
• Filed: 12/20/2012
• Issued: 01/31/2017
• Est. Priority Date: 12/20/2012
• Status: Active Grant

• Current Assignee: Volvo Truck Corporation (Volvo AB)
• Original Assignee: Volvo Truck Corporation (Volvo AB)
• Inventors: Preijert, Stefan
• Primary Examiner(s): Sweeney, Brian P
• Application Number:
  US14/654,038
• Publication Number:
  US 20150329141A1
• Time in Patent Office: 1,503 Days
• Field of Search: 701/41
• US Class Current: 1/1
• CPC Class Codes: B62D 1/16 Steering columns
• CPC Class Codes: B62D 5/0463 calculating assisting torque from the motor based on driver input
• CPC Class Codes: B62D 6/008 Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications
• CPC Class Codes: B62D 6/04 responsive only to forces disturbing the intended course of the vehicle, e.g. forces acting transversely to the direction of vehicle travel

Abstract

A method for assisting a driver of a vehicle during operation by providing the driver with a desired steering feel, involves detecting a first steering angle for an output shaft, which first steering angle indicates the position of ground engaging members; detecting a second steering angle for an input shaft, which second steering angle indicates the position of a steering device; comparing the first and second steering angles and determining a current state of a steering arrangement; and controlling a first actuator connected to the output shaft and a second actuator connected to the input shaft in response to the detected first and second steering angles, in order to achieve a desired state of the steering arrangement; and applying a torque to the steering device proportional to the angular difference between the output shaft and the input shaft using a resilient portion in an interconnection. An arrangement is also disclosed.

Claims

1. A method for assisting a driver of a vehicle during operation by providing the driver with a desired steering feel, wherein the vehicle comprises a steering arrangement comprising an input shaft connected to a manually operated steering device, an output shaft connected to at least one pair of ground engaging members and a mechanical interconnection connecting the output shaft and the input shaft, comprising

detecting a first steering angle for the output shaft, which first steering angle indicates the position of the ground engaging members;

detecting a second steering angle for the input shaft, which second steering angle indicates the position of the steering device;

comparing the first and second steering angles and determining a current state of the steering arrangement; and

controlling a first actuator connected to the output shaft and a second actuator connected to the input shaft in response to the detected first and second steering angles, in order to achieve a desired state of the steering arrangement;

applying a torque to the steering device proportional to the angular difference between the output shaft and the input shaft using a resilient portion in the mechanical interconnection, in order to provide the driver with a desired steering feel.

2. Method according to claim 1, comprising controlling the first and the second actuators by applying torque to the input shaft and the output shaft in opposite directions in response to the determined current state of the steering arrangement.

3. Method according to claim 1, comprising

detecting a changing first steering angle indicating a deflection of the ground engaging members;

detecting a constant second steering angle indicating a fixed position of the steering device;

controlling the first and the second actuators in response to the detected first steering angle;

counteracting the torque transmitted from the ground engaging members by applying an equal and opposite torque to the output shaft; and

counteracting the torque transmitted from the output shaft by applying an equal and opposite torque to the input shaft to maintain a constant second steering angle for the steering device.

4. Method according to claim 3, comprising controlling the first and the second actuators to apply a fluctuating torque in equal and opposite directions to counteract a fluctuating torque from the ground engaging member during a bump steer condition.

5. Method according to claim 3, comprising controlling the first and the second actuators to apply a continuous torque in equal and opposite directions to counteract a suspension induced torque from a steering linkage connecting the ground engaging members and the output shaft.

6. Method according to claim 5, comprising applying the continuous torque to maintain the steering device in a predetermined position, in order to provide steering error compensation.

7. Method according to claim 1, comprising

detecting a current first steering angle indicating a deflection of the ground engaging members;

detecting a current second steering angle indicating a steering input from the steering device;

controlling the first and the second actuators in response to the detected first steering angle;

applying a first torque to the output shaft to transmit a steering torque to the ground engaging members in response to the steering input; and

applying a second torque to the input shaft in the opposite direction providing a resistance to the steering input.

8. Method according to claim 7, comprising applying a first torque that is less than the second torque to provide a steering feel indicating understeer.

9. Method according to claim 7, comprising, applying a first torque that is greater than the second torque to provide a steering feel indicating oversteer.

10. Steering arrangement in a vehicle, which power steering arrangement comprises an input shaft connected to a manually operated steering device, an output shaft connected to at least one pair of ground engaging members and a mechanical interconnection between the input shaft and the output shaft, and angular sensors arranged to detect the angular positions of the steering device and the ground engaging members and an electronic control unit arranged to determine a current state of the steering arrangement, wherein the power steering arrangement farther comprises a first actuator connected to the output shaft, a second actuator connected to the input shaft, and an elastic steering force transmitting element connecting the input shaft and the output shaft,

wherein the first and the second actuators are individually controllable and are arranged to rotate the output shaft and the input shaft, respectively, in opposite directions in response to the detected angular positions of the steering device and the ground engaging members, and the current state of the steering arrangement, and

wherein the steering force transmitting element is arranged to apply a torque to the steering device proportional to the angular difference between the output shaft and the input shaft.

11. Steering arrangement according to claim 10, wherein the first and the second actuators are arranged to apply torque to the output shaft and the input shaft in opposite directions in response to the determined current state of the steering arrangement.

12. Steering arrangement according to claim 10, wherein the first and the second actuators are arranged to apply a fluctuating torque in equal and opposite directions to counteract a fluctuating torque from the ground engaging members (4) during a bump steer condition.

13. Steering arrangement according to claim 10, wherein the first and the second actuators are arranged to apply a continuous torque in equal and opposite directions to counteract a suspension induced torque from a steering linkage connecting the ground engaging members and the output shaft, in order to maintain the steering device in a predetermined position.

14. Steering arrangement according to claim 10, wherein the first actuator is arranged to apply a first torque to the output shaft to transmit a steering torque to the ground engaging members in response to the steering input;

and that the second actuator is arranged to apply a second torque to the input shaft in the opposite direction providing a resistance to the steering input.

15. Steering arrangement according to claim 14, wherein the first torque is less than the second torque to provide a steering feel indicating understeer.

16. Steering arrangement according to claim 14, wherein the first torque that is greater than the second torque to provide a steering feel indicating oversteer.

17. Steering arrangement according to claim 10, wherein the first and the second actuators are arranged to apply torque to the output shaft and the input shaft in the same direction in response to the determined current state of the steering arrangement, in order to provide steering assistance.

18. Vehicle, comprising a power steering arrangement, the power steering arrangement comprising an input shaft connected to a manually operated steering device, an output shaft connected to at least one pair of ground engaging members and a mechanical interconnection between the input shaft and the output shaft, and angular sensors arranged to detect the angular positions of the steering device and the around engaging members and an electronic control unit arranged to determine a current state of the steering arrangement, wherein the power steering arrangement further comprises a first actuator connected to the output shaft, a second actuator connected to the input shaft, and an elastic steering force transmitting element connecting the input shaft and the output shaft,

wherein the first and the second actuators are individually controllable and are arranged to rotate the output shaft and the input shaft, respectively, in opposite directions in response to the detected angular positions of the steering device and the ground engaging members, and the current state of the steering arrangement, and

wherein the steering force transmitting element is arranged to apply a torque to the steering device proportional to the angular difference between the output shaft and the input shaft.

19. A computer comprising a program stored on a non-transitory computer readable medium for performing all the steps of a method for assisting a driver of a vehicle during operation by providing the driver with a desired steering feel, wherein the vehicle comprises a steering arrangement comprising an input shaft connected to a manually operated steering device, an output shaft connected to at least one pair of ground engaging members and a mechanical interconnection connecting the output shaft and the input shaft, comprising

detecting a first steering angle for the output shaft, which first steering angle indicates the position of the ground engaging members;

detecting a second steering angle for the input shaft, which second steering angle indicates the position of the steering device;

comparing the first and second steering angles and determining a current state of the steering arrangement; and

controlling a first actuator connected to the output shaft and a second actuator connected to the input shaft in response to the detected first and second steering angles, in order to achieve a desired state of the steering arrangement;

applying a torque to the steering, device proportional to the angular difference between the output shaft and the input shaft using a resilient portion in the mechanical interconnection, in order to provide the driver with a desired steering feel.

20. A computer program product comprising a program stored on a non-transitory computer readable medium for performing all steps of a method for assisting a driver of a vehicle during operation by providing the driver with as desired steering feel, wherein the vehicle comprises a steering arrangement comprising an input shaft connected to a manually operated steering device, an output shaft connected to at least one pair of ground engaging members and a mechanical interconnection connecting the output shaft and the input shaft, comprising

detecting a first steering angle for the output shaft, which first steering angle indicates the position of the ground engaging members;

detecting a second steering angle for the input shaft, which second steering angle indicates the position of the steering device;

comparing the first and second steering angles and determining a current state of the steering arrangement; and

controlling a first actuator connected to the output shaft and a second actuator connected to the input shaft in response to the detected first and second steering angles, in order to achieve a desired state of the steering arrangement;

applying a torque to the steering device proportional to the angular difference between the output shaft and the input shaft using, a resilient portion in the mechanical interconnection, in order to provide the driver with a desired steering feel when the program product is run on a computer.

21. A non-transitory storage medium for use in a computer, comprising a computer readable program to perform a method for assisting a driver of a vehicle during operation by providing the driver with a desired steering feel, wherein the vehicle comprises a steering arrangement comprising an input shaft connected to a manually operated steering device, an output shaft connected to at least one pair of ground engaging members and a mechanical interconnection connecting the output shaft and the input shaft, comprising

detecting a first steering angle for the output shaft, which first steering angle indicates the position of the ground engaging members;

detecting a second steering angle for the input shaft, which second steering angle indicates the position of the steering device;

comparing the first and second steering angles and determining a current state of the steering arrangement; and

controlling a first actuator connected to the output shaft and a second actuator connected to the input shaft in response to the detected first and second steering angles, in order to achieve a desired state of the steering arrangement;

applying a torque to the steering device proportional to the angular difference between the output shaft and the input shaft using a resilient portion in the mechanical interconnection, in order to provide the driver with a desired steering feel.