Motor vehicle with driven wheels on a number of axles and method for controlling same

Abstract

A motor vehicle is controlled via a method, particularly for steering during a malfunction. Two wheels are arranged on a steerable axle of the motor vehicle and each can be driven by a single-wheel drive. At least one wheel is arranged on a non-steerable axle of the motor vehicle and can be driven by a wheel drive. In the event of a malfunction of one of the single-wheel drives being identified, a drive torque or a braking torque is generated with the functioning single-wheel drive of the wheel arranged on the steerable axle of the motor vehicle to steer the wheels arranged on the steerable axle in a specified direction. A drive torque or a braking torque is generated with the wheel drive of the wheel arranged on the non-steerable axle of the motor vehicle to at least partially bring about a specified longitudinal movement of the motor vehicle.

Claims

1. A method for controlling a motor vehicle, wherein the motor vehicle comprises several wheels, wherein two of the several wheels are arranged on a steerable axle of the motor vehicle and are respectively driven by individual wheel drives; wherein at least one of the several wheels is arranged on a non-steerable axle of the motor vehicle and is driven by an individual wheel drive; and wherein the method comprises the following steps: detecting a malfunction of one of the individual wheel drives of the wheels that are arranged on the steerable axle of the motor vehicle, wherein another of the individual wheel drives of the wheels arranged on the steerable axle of the motor vehicle is still fully functional; in response to the detected malfunction, generating a drive torque or a braking torque with the functional individual wheel drive of the wheel that is arranged on the steerable axle of the motor vehicle in order to steer the wheels arranged on the steerable axle in a predetermined direction; and in response to the detected malfunction, generating a drive torque or a braking torque with the wheel drive of the wheel that is arranged on the non-steerable axle of the motor vehicle in order to at least partially effect a predetermined longitudinal movement of the motor vehicle.

2. The method according to claim 1, wherein the generating of a drive torque or a braking torque with the functional individual wheel drive of the wheel that is arranged on the steerable axle of the motor vehicle and the generating of a drive torque or a braking torque with the wheel drive of the wheel that is arranged on the non-steerable axle of the motor vehicle additionally also take place in order to effect, at least partially, a predetermined yaw moment on the motor vehicle.

3. The method according to claim 1, wherein: a drive torque is respectively generated with the fully functional individual wheel drive of the wheel that is arranged on the steerable axle of the motor vehicle and with the wheel drive of the wheel that is arranged on the non-steerable axle of the motor vehicle.

4. The method according to claim 1, wherein the motor vehicle additionally has a controllable braking device for braking a steering movement of the wheels that are arranged on the steerable axle of the motor vehicle, wherein the method further comprises: activating the braking device to prevent any further steering movement once the wheels that are arranged on the steerable axle have been steered in the predetermined direction.

5. The method according to claim 4, wherein, once the braking device has been activated in order to prevent any further steering movement, a drive torque or a braking torque is generated with the fully functional individual wheel drive of the wheel that is arranged on the steerable axle of the motor vehicle in order to at least partially effect the predetermined longitudinal movement of the motor vehicle.

6. The method according to claim 4, wherein the controllable braking device effects a blocking of the steering movement of the wheels that are arranged on the steerable axle of the motor vehicle.

7. The method according to claim 4, wherein the controllable braking device effects a variable braking force or a variable braking torque for braking the steering movement of the wheels that are arranged on the steerable axle of the motor vehicle.

8. The method according to claim 4, wherein the controllable braking device for braking a steering movement acts on a displaceable rod that transmits a steering movement to the wheels that are arranged on the steerable axle of the motor vehicle.

9. The method according to claim 4, wherein the controllable braking device for braking a steering movement effects a braking torque in order to brake a steering rotation of the wheels arranged on the steerable axle of the motor vehicle.

10. A motor vehicle with several wheels, wherein two of the wheels are arranged on a steerable axle of the motor vehicle and are respectively driven by individual wheel drives, wherein at least one of the wheels is arranged on a non-steerable axle of the motor vehicle and is driven by a wheel drive, and wherein the motor vehicle additionally comprises a control unit for controlling the individual wheel drives and the controller is configured for carrying out a method according to claim 1.

11. The method according to claim 1, wherein: a braking torque is respectively generated with the fully functional individual wheel drive of the wheel that is arranged on the steerable axle of the motor vehicle and with the wheel drive of the wheel that is arranged on the non-steerable axle of the motor vehicle.

12. The method according to claim 1, wherein: a drive torque is generated with the fully functional individual wheel drive of the wheel that is arranged on the steerable axle of the motor vehicle, and a braking torque is generated with the wheel drive of the wheel that is arranged on the non-steerable axle of the motor vehicle.

13. The method according to claim 1, wherein: a braking torque is generated with the fully functional individual wheel drive of the wheel that is arranged on the steerable axle of the motor vehicle, and a drive torque is generated with the wheel drive of the wheel that is arranged on the non-steerable axle of the motor vehicle.

14. A motor vehicle comprising: a first steerable wheel driven by a first wheel motor; a second steerable wheel driven by a second wheel motor; an unsteerable wheel driven by a third wheel motor; and a controller configured to detect a failure of the first wheel motor and respond by commanding a first torque from the second wheel motor and a second torque from the third wheel motor to induce a predefined steering angle and a predefined longitudinal force.

15. The motor vehicle of claim 14 further comprising a steering brake configured to selectively hold the first and second steerable wheels at the predefined steering angle and wherein the controller is further configured to command the steering brake to engage after inducing the predefined steering angle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Additional advantages, details, and further developments will become apparent from the below description of a preferred embodiment, with reference to the drawing. The sole FIGURE is a schematic representation of a vehicle.

DETAILED DESCRIPTION

[0035] The sole FIGURE shows a schematic representation of two front wheels 01 on a steerable axle and two back wheels 02 on a non-steerable axle of a motor vehicle 03 during one step of a preferred embodiment of a method. The two front wheels 01 on the steerable axle and the two back wheels 02 on the non-steerable axle of the motor vehicle 03 may be driven respectively by individual wheel drives (not shown). The steering movement of the front wheels 01 is linked together via steering levers 04 and a steering rod 06. The motor vehicle 03 includes a controllable braking device 07 for braking a steering movement of the front wheels 01. The controllable braking device 07 acts on the steering rod 06 and may block a displacement of the steering rod 06 in the y-direction.

[0036] The method is provided for the case in which one of the individual wheel drives (not shown) of the front wheels 01 on the steerable axle of the motor vehicle 03 has a malfunction. In the example shown, the individual wheel drive (not shown) of the front wheel 01 arranged on the right side of the steerable axle of the motor vehicle 03 has failed such that the right front wheel 01 cannot be driven.

[0037] In the example shown, a drive torque is generated with the individual wheel drive (not shown) of the front wheel 01 that is arranged on the left side on the steerable axle of the motor vehicle 03 in order to steer the front wheels 01 in a desired direction 08. Correspondingly, a force F.sub.x,vl acts on the left front wheel 01. In the y direction, a force F.sub.y,vl acts on the front left wheel 01, and a force F.sub.y,vr acts on the front right wheel 01.

[0038] In the example shown, a braking torque is generated with the individual wheel drive (not shown) of the back wheel 02 that is arranged on the right side of the non-steerable axle of the motor vehicle 03 in order to effect a predetermined longitudinal movement of the motor vehicle 03. Correspondingly, a force F.sub.x,hr acts on the right back wheel 02. In the y direction, a force F.sub.y,hl acts on the back left wheel 02, and a force F.sub.y,hr acts on the back right wheel 02.

LIST OF REFERENCE SYMBOLS

[0039] 01 front wheel [0040] 02 back wheel [0041] 03 motor vehicle [0042] 04 steering lever [0043] 05 — [0044] 06 steering rod [0045] 07 controllable braking device [0046] 08 direction