VEHICLE HAVING A WHEEL-SELECTIVE DRIVE TORQUE ASSEMBLY AND ARTICULATED JOINT, AND METHOD FOR CONTROLLING THE VEHICLE

Abstract

A vehicle is proposed having a first axle portion, wherein the first axle portion has a first axle, a second axle portion, wherein the second axle portion has a second axle, a wheel-selective drive torque arrangement, wherein at least one of the axles is designed as an axle influenced by the wheel-selective drive torque arrangement, and a control device, wherein the control device is designed to control the wheel-selective drive torque arrangement in order to convert a steering command into cornering of the vehicle, and an articulated joint, wherein the first and second axle portions are coupled to one another by the articulated joint.

Claims

1. A vehicle comprising: a first axle portion, wherein the first axle portion has a first axle, a second axle portion, wherein the second axle portion has a second axle, a wheel-selective drive torque arrangement, wherein at least one of the axles is designed as an axle influenced by the wheel-selective drive torque arrangement, a control device, wherein the control device is designed to control the wheel-selective drive torque arrangement in order to convert a steering command into cornering of the vehicle, and an articulated joint, wherein the first and the second axle portion are coupled to one another by the articulated joint.

2. The vehicle according to claim 1, wherein the vehicle can assume a straight ahead operating state, wherein an articulation angle of the articulated joint is 0, and the vehicle can assume a cornering operating state, wherein an articulation angle of the articulated joint is not equal to 0.

3. The vehicle according to claim 1, wherein the drive torque arrangement has a wheel-selective drive arrangement or a wheel-selective deceleration arrangement.

4. The vehicle according to claim 3, wherein the wheel-selective drive arrangement has two wheel motors on a driven axle as the at least one torque-influenced axle or the wheel-selective deceleration arrangement has two selectively controllable brakes on a braked axle as the at least one torque-influenced axle.

5. The vehicle according to claim 1, wherein the first and second axles are designed as unsteered axles.

6. The vehicle according to claim 1, wherein the articulated joint is designed as a passive articulated joint.

7. The vehicle according to claim 1, wherein one of the axles is designed as the torque-influenced axle and the other axle is designed as a passive axle.

8. The vehicle according to claim 1, wherein both axles are designed as torque-influenced axles.

9. A method for controlling the vehicle according to claim 1, wherein cornering is implemented by introducing different drive torques onto the wheels of the at least one torque-influenced axle.

10. The method for controlling the vehicle according to claim 9, characterized in that the articulation angle of the articulation joint is changed by changing the drive torque distribution on the wheels of the at least one torque-influenced axle.

11. The vehicle of claim 7 wherein the torque-influenced axle is a rear axle.

12. A method of controlling a vehicle, the vehicle comprising: a front axle portion having a first axle; and a rear axle portion having a second axle and coupled to the front axle portion by an articulated joint; the method comprising: in response to a steering input, commanding a differential torque on one of the first axle and the second axle.

13. The method of claim 12 wherein the rear axle portion has an inside rear wheel and an outside rear wheel relative to the steering input and commanding a differential torque on one of the first axle and the second axle comprises commanding a first positive torque for the inside rear wheel and a second positive torque, less than the first positive torque for the outside rear wheel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Further features, advantages, and effects result from the following description of a preferred embodiment. In the figures:

[0029] FIG. 1 shows a schematic block diagram of a vehicle;

[0030] FIG. 2 shows a schematic illustration of the steering method with the vehicle from FIG. 1.

DETAILED DESCRIPTION

[0031] FIG. 1 shows a vehicle 1 in a schematic block diagram. The vehicle 1 has a first axle portion 2a and a second axle portion 2b. The axle portions 2a, b are arranged one behind the other in the longitudinal direction of the vehicle 1. In the exemplary embodiment shown, the axle portions 2a, b are designed as vehicle halves, in particular the vehicle 1 is divided in the middle. In alternative exemplary embodiments, the division of the vehicle 1 can also be asymmetrical. The axle portion 2a has an axle 3a, the axle portion 2b has an axle 3b. The axles 3a, 3b each have two wheels 4. The wheels 4 are arranged in the respective axle portions 2a, b, non-pivotably mounted with respect to a vertical axis of the vehicle 1. In particular, the wheels 4 are arranged rigidly and/or non-pivotably with respect to a steering angle of the wheels 4.

[0032] The wheels 4 of the first axle 3a each have a wheel motor 5, which is in particular designed as a wheel hub motor. The first axle 3a thus has two wheel motors 5 and is designed as a driven axle. In the same way, the wheels 4 of the second axle 3b are each assigned a wheel motor 5, which in particular is designed as a wheel hub motor. Optionally, in addition, the wheels 4 of the first and second axles 3a, 3b each have a brake 13. The first and second axles a, b are thus designed as torque-influenced axles. The wheel motors 5 are controlled by a control device 6 so that each wheel 5 can be selectively assigned a freely selectable drive torque. Optionally, in addition, the brakes 13 are controlled via the control device 6 so that each wheel 5 can be selectively assigned a freely selectable negative drive torque, in particular deceleration torque and/or braking torque. The wheel motors 5 together form a wheel-selective drive arrangement 10. The brakes 13 together form a wheel-selective deceleration arrangement 11. The wheel-selective drive arrangement 10 and the wheel-selective deceleration arrangement 11, together or individually, form a wheel-selective drive torque arrangement 12.

[0033] The vehicle 1 has a control device 6 for controlling the wheel motors 5 and optionally, in addition, the brakes 13 and thus the wheel-selective drive torque arrangement 12. The control device 6 is designed as a digital data processing device.

[0034] The control device 6 has an output interface 7 for data coupling with the wheel motors 5 and optionally, in addition, with the brakes 13. Furthermore, the control device 6 has an input interface 8 for receiving a steering command. Optionally, in addition, further parameters such as driving speed specification of the driver and vehicle condition variables may also be passed. For example, the input interface 8 can have a data connection to a steering wheel of the vehicle 1 for receiving the steering command.

[0035] The vehicle 1 has an articulated joint 9, via which the first and second axle portions 2a, 2b are connected to one another so as to be pivotable about the vertical axis of the vehicle 1. The articulated joint 9 is designed as a purely mechanical joint that is free of external energy and is pivoted passively. When the vehicle 1 is traveling straight ahead, an articulation angle between the first axle portion 2a and the second axle portion 2b is 0. The pivot angle is increased when cornering.

[0036] The steering strategy of vehicle 1 is a steering system for vehicle 1 with articulated steering, the steering force for setting the articulation angle being generated by wheel-selective influencing of the drive torques on wheels 4. The steering force is thus generated directly from the drive train, namely by the wheel motors 5, and optionally, in addition, from the brakes 13.

[0037] FIG. 2 shows the vehicle 1 reduced to the functional portions, the first and second axle portions 2a, 2b again being shown. The vehicle 1 is in an operating state of cornering. FIG. 2 shows the operating principle of steering of the vehicle 1 by torque vectoring and/or brake force distribution in the vehicle 1 with articulated steering. If, for example, a higher drive torque is transmitted to the left rear wheel 4, that is to say the wheel on the inside of the curve, than to the right rear wheel 4, that is to say the wheel on the outside of the curve, the second axle 3b rotates about an articulation point which is guided by the articulation joint 9. In this way, a change in the articulation angle of the articulated joint 9 is initiated via the distribution of the drive torques. As an alternative or in addition, the articulation angle can be changed if a greater drive torque is transmitted to the right front wheel 4, that is to say the wheel on the outside of the curve, than to the left front wheel 5, that is to say the wheel 5 on the inside of the curve.

[0038] The basic ideas are as follows: Conventional commercial vehicles with articulated steering (see prior art) rely on hydraulic power steering. However, there are some negative aspects associated with a hydraulic device. On the one hand, the actuator requires a large installation space in the area of the steering system and its existence also results in a higher vehicle weight. On the other hand, the steering energy requirement is higher by a factor of 3 compared with axle steering. This is particularly important when steering in a stationary position. Another disadvantage of hydraulic power steering is the high load on the frame parts.

[0039] Torque vectoring (wheel-specific torque distribution) or EPS (wheel-specific deceleration) is being used increasingly, especially in future mobile machinery. This means that a vehicle with wheel-selective drives or brakes can be steered on the various axles or wheels by means of different drive torques. Torque vectoring or braking force distribution can be used in an energy-efficient manner in conjunction with articulated vehicles. FIG. 2 shows the principle of operation of steering by torque vectoring or brake force distribution in vehicles with articulated steering. If, for example, a higher drive torque is transmitted to the left rear wheel 4 than to the right rear wheel 4, the rear axle 3b rotates about the articulation point of the articulation joint 9.

[0040] It is assumed that vehicles 1 with articulated steering can be steered completely by torque vectoring and/or brake force distribution so that the hydraulic external power steering previously required can be completely substituted. However, this requires the use of a suitable drive train, optionally a suitable deceleration arrangement, a suitable chassis and intelligent control. By using torque vectoring and/or braking force distribution in conjunction with articulated steering, there are several advantages: The greatest benefit lies in the elimination of hydraulic power steering, which can save space and weight. At the same time, the turning radius of the vehicle 1 can be significantly reduced or the maximum pivot angle reduced, which also reduces the risk of the vehicle tipping over. In addition, the so-called jackknife effect, i.e., the unwanted folding of the vehicle 1 can be avoided. There is also a high energy potential with torque vectoring and/or brake force distribution compared with hydraulic power steering, especially when steering in a stationary position and at lower speeds.

LIST OF REFERENCE SYMBOLS

[0041] 1 vehicle [0042] 2a, 2b axle portions [0043] 3a, 3b axles [0044] 4 wheels [0045] 5 wheel motors [0046] 6 control device [0047] 7 output interface [0048] 8 input interface [0049] 9 articulated joint [0050] 10 wheel-selective drive arrangement [0051] 11 wheel selective deceleration arrangement [0052] 12 wheel-selective drive torque arrangement [0053] 13 brakes