Modular drive and steering system

Abstract

The invention relates to a modular drive and steering system, comprising a chassis, a first drive and steering module, a second drive and steering module, and a control unit, wherein each of the drive and steering modules has a passive wheel unit and an active wheel unit. Each passive wheel unit has two running wheels, which are arranged such that they can be rotated about a common running wheel horizontal axis and they are axially spaced apart. Each active wheel unit has a bogie and a drive wheel which is rotatably arranged thereon, with which a wheel drive is associated. The bogie is rotatably mounted on the chassis about a first vertical axis and a steering drive is associated with same. The two running wheels and the drive wheel of both drive and steering modules span a respective triangle in relation to one another, wherein the running wheel horizontal axes are arranged parallel to one another and the drive wheel units are arranged opposite on another on both sides of the running wheel horizontal axes. The control unit is connected to the steering drives and the wheel drives and designed to generate drive control commands and to transmit same to the wheel drives, as well as to generate steering control commands and to transmit same to the steering drives.

Description

[0001] Modular drive and steering system

[0002] The invention relates to a modular drive and steering system for mobile platforms, which can be designed for both cargo and passenger transport, particularly for urban applications.

[0003] Different drive and steering systems for such driving platforms are known from the state of the art.

[0004] For example, classic steering knuckles are well known. Their disadvantages are their comparatively complex design and the limitations of the steering geometry.

[0005] DE 20 2019 003 072 U1 proposes a modular driving unit that solves the problem of limited steering geometries and presents a driving platform that allows for a wide variety of steering movements. This solution makes an important contribution to the state of the art, but it is comparatively technically demanding.

[0006] The object of the invention is to provide a modular solution for a drive and steering system that has good steering behavior and high cornering stability and is universally suitable for outdoor and indoor applications.

[0007] The problem is solved by the features listed in patent claim 1. Preferred developments arise from the subclaims.

[0008] The modular drive and steering system according to the invention comprises, as basic components, a chassis, a first drive and steering module, a second drive and steering module, and a control unit. The numbers "first" and "second" are not intended to be a ranking within the meaning of the present invention, but merely serve to clearly identify the components.

[0009] The first drive and steering module has a first passive wheel unit and a first active wheel unit.

[0010] According to the invention, the first passive wheel unit comprises two first wheels arranged rotatably about a common first horizontal wheel axis. They are further arranged axially spaced apart on this first horizontal wheel axis. The first horizontal wheel axis is fixed relative to the chassis and arranged transversely to the main longitudinal axis of the chassis. In this case, the common first horizontal wheel axis is understood as a geometric category, so that in physical terms, each of the two first wheels preferably has a separate axis. A passive wheel unit is understood to mean that no drive torque is generated by the wheels.

[0011] The first active wheel unit has a first bogie and a first drive wheel. The first bogie is arranged on the chassis.

[0012] According to the invention, the bogie is actively mounted for rotation about a first vertical axis. For this purpose, a first steering drive is assigned to the bogie, which can provide a steering torque, thus causing the bogie to rotate about the vertical axis. The steering drive is preferably designed as a torque motor.

[0013] The first drive wheel is mounted on the first bogie so that it can actively rotate about a first drive wheel horizontal axis. A first wheel drive is assigned to the first drive wheel for active rotation. The first wheel drive is preferably an electric motor. The drive wheel horizontal axis is not fixed relative to the chassis, but rather follows a rotation of the chassis. Thus, the drive wheel horizontal axis is rotatable in a main plane of the chassis.

[0014] According to the invention, the positional relationship between the passive wheel unit and the active wheel unit is defined such that the two first impellers and the first drive wheel form a first triangle relative to each other. This is preferably an isosceles triangle, with the base being the first impeller's horizontal axis and the sides being formed by the connecting lines between the first drive wheel and each of the two first impellers.

[0015] The second drive and steering module has a second passive wheel unit and a second active wheel unit.

[0016] According to the modularity according to the invention, the first drive and steering module and the second drive and steering module are constructed in the same way, so that the description contents of the first drive and steering module also apply correspondingly to the second drive and steering module.

[0017] According to the invention, the first horizontal wheel axis and the second horizontal wheel axis are arranged parallel to each other and preferably exactly orthogonal to the main longitudinal axis of the travel platform. The first drive wheel unit and the second drive wheel unit are arranged opposite each other and also on either side of the horizontal wheel axes.

[0018] The triangles spanned by the first drive and steering module and the second drive and steering module are preferably identical and arranged mirrored about an axis of symmetry lying between the horizontal axes of the impeller wheels. However, it is also possible for the distance of the first drive wheel unit from the first horizontal axis of the impeller wheel and the distance of the second drive wheel unit from the second horizontal axis of the impeller wheel to differ from one another.

[0019] The modular drive and steering system also includes the control unit. This is connected to the first and second steering drives as well as to the first and second wheel drives.

[0020] The control unit according to the invention is designed, first, to generate drive control commands and transmit them to the wheel drives, and second, to generate steering control commands and transmit them to the steering drives. The steering control commands cause the two bogies to turn in opposite directions, thus achieving a constant velocity steering system.

[0021] The control unit is preferably an electronic circuit or a processor.

[0022] The modular drive and steering system according to the invention has in particular the following advantages.

[0023] Surprisingly, a solution was found that allows for both high load capacity and good steering behavior using simple means.

[0024] Advantageously, the main load is distributed via the two passive wheel units, thus relieving the load on the active wheel unit.

[0025] At the same time, the problem that reducing the load on the steered axle can be accompanied by a reduction in steering stability is advantageously solved by providing two opposing active wheel units. Particularly during acceleration or deceleration, one of the two active wheel units is always subjected to a higher load due to the tilting moment about the transverse or pitch axis, thus ensuring high lateral traction of the respective drive wheel. In the case of acceleration, this applies to the rear drive wheel, and in the case of deceleration, to the front drive wheel.

[0026] Furthermore, it is advantageous that these driving dynamics advantages can be achieved in a simple manner by arranging a drive and steering module in a similar manner twice and preferably symmetrically.

[0027] The constant velocity steering system also advantageously allows for a particularly tight turning circle. In particular, it is advantageous that the instantaneous center of gravity, i.e., the point around which steering occurs, can even be located within the axial distance formed by the road wheels.

[0028] According to an advantageous further development, the modular drive and steering system is characterized in that the first drive wheel or the second drive wheel is designed as a double wheel.

[0029] According to this refinement, at least one of the drive wheels, but preferably both, is designed as a double wheel. A double wheel is understood to be a drive wheel in which two individual wheels are mounted at a close distance on one and the same drive shaft, in this case on the drive wheel's horizontal axis.

[0030] The advantage of this further training is that with little additional effort there is significantly improved traction and more stable driving and steering behavior.

[0031] According to a further advantageous development, the modular drive and steering system is characterized in that the first passive wheel unit and the second passive wheel unit are integrated into one another, and in that the first two running wheels simultaneously form the second two running wheels. According to this development, the drive and steering system according to the invention has a total of two running wheels and two drive wheel units, so that the two spanned, preferably isosceles triangles have a common base side. Particularly preferably, both drive wheel units are arranged at the same distance perpendicular to the common running wheel horizontal axis, so that the running wheel horizontal axis simultaneously forms an axis of symmetry lying transversely to the main longitudinal axis.

[0032] This further simplifies the technical solution. This advantageously eliminates any risk of wheel slippage, even in the tightest turning radii. This even applies when the modular drive and steering system rotates around its own vertical or yaw axes.

[0033] The invention is illustrated by way of example with reference to

[0034] Fig. 1 Schematic representation in a basic form

[0035] Fig. 2 Simplified schematic representation with double wheel

[0036] Fig. 3 Simplified schematic representation with integrated passive units and with double wheel

[0037] Fig. 4 Simplified schematic representation with integrated passive units explained in more detail.

[0038] Identical reference numerals in the various figures refer to identical features or components. These reference numerals are used in the description even if they are not shown in the respective figure. Fig. 1 shows a schematic representation of an embodiment in a basic form.

[0039] The first steering and drive module 1 comprises the first passive wheel unit 1.1 with the first two running wheels 1.11, which are arranged along the first running wheel horizontal axis 1.12. The two first running wheels 1.11 are axially spaced apart, which in this case essentially corresponds to the width of the driving platform 3. The second passive wheel unit 2.1 with the second two running wheels 2.11 is arranged mirror-symmetrically and at a short distance along the main longitudinal axis of the driving platform on the second running wheel horizontal axis 2.12.

[0040] Each of the two steering and drive modules 1, 2 also has a bogie 1.21, 2.21, each of which can be actively rotated about a vertical axis 1.22, 2.22 (here arranged transversely to the schematic representation plane and therefore represented by a dot) by means of a steering drive 1.23, 2.23, here a torque motor. This determines the steering angle of the respective drive wheel 1.24,

[0041] 2.24, whereby their respective drive wheel horizontal axes 1.25, 2.25 pivot (represented by the curved double arrows). The first drive wheel

[0042] 1.24 is driven by the first wheel drive 1.26 and the second drive wheel 2.24 is driven by the second wheel drive 2.26.

[0043] The control unit 4 is connected to the first steering drive 1.23 and the first wheel drive 1.26 as well as to the second steering drive 2.23 and the second wheel drive 2.26 and thus transmits the drive control commands to the wheel drives 1.26, 2.26 and the steering control commands to the steering drives 1.23, 2.23.

[0044] Figs. 2 to 4 are simplified schematic representations in which, for the sake of clarity, the drives 1.23, 1.24, 2.23, 2.24 and the control unit 4 have been omitted. Fig. 2 essentially corresponds to the embodiment according to Fig. 1, but has a double wheel as the drive wheel 1.24, 2.24. In Fig. 2, the two triangles formed by the running wheels 1.11, 2.11 and the drive wheels 1.22, 2.22 are also shown as bold dashed lines to clarify the positional relationships.

[0045] Fig. 3 shows an embodiment in which the first and second passive wheel units 1.1, 2.1 are integrated into one another, resulting in only one common horizontal wheel axis 1.25, 2.25 and two common wheels 1.24, 2.4. In this embodiment, the drive wheels 1.24, 2.24 are also designed as double wheels.

[0046] Fig. 4 shows a further embodiment. This essentially corresponds to the embodiment shown in Fig. 3, but as a simplification, it has drive wheels 1.24, 2.24, each designed as a single wheel.

[0047] Reference symbols used

[0048] 1 first drive and steering module

[0049] 1.1 first passive wheel unit

[0050] 1.11 two first wheels

[0051] 1.12 first impeller horizontal axis

[0052] 1.2 first active wheel unit

[0053] 1.21 first bogie

[0054] 1.22 first vertical axis

[0055] 1.23 first steering drive

[0056] 1.24 first drive wheel

[0057] 1.25 first drive wheel horizontal axis

[0058] 1.26 first wheel drive

[0059] 2 second drive and steering module

[0060] 2.1 first passive wheel unit

[0061] 2.11 two first wheels

[0062] 2.12 second impeller horizontal axis

[0063] 2.2 second active wheel unit

[0064] 2.21 second bogie

[0065] 2.22 second vertical axis

[0066] 2.23 second steering drive

[0067] 2.24 second drive wheel

[0068] 2.25 second drive wheel horizontal axis

[0069] 2.26 second wheel drive

[0070] 3 Chassis

[0071] 4 Control unit

Claims

Patent claims 1. Modular drive and steering system comprising a chassis (3), a first drive and steering module (1), a second drive and steering module (2), and a control unit (4), wherein the first drive and steering module (1) comprises a first passive wheel unit (1.1) and a first active wheel unit (1.2), wherein the first passive wheel unit (1.1) comprises two first running wheels (1.11) rotatably arranged about a common first running wheel horizontal axis (1.12) and axially spaced, wherein the first active wheel unit (1.2) comprises a first bogie (1.21) and a first drive wheel (1.24), wherein the first bogie (1.21) is rotatably mounted on the chassis (3) about a first vertical axis (1.22), and a first steering drive (1.23) is assigned to the first bogie (1.21), wherein the first drive wheel (1.24) is mounted on the first bogie (1.21). arranged rotatably about a first drive wheel horizontal axis (1.25) and connected to the first drive wheel (1.24) a first wheel drive (1.26) is assigned, wherein the two first running wheels (1.11) and the first drive wheel (1.24) form a first triangle with respect to each other, wherein the second drive and steering module (2) has a second passive wheel unit (2.1) and a second active wheel unit (2.2). wherein the second passive wheel unit (2.1) has two second running wheels (2.11) which are rotatably arranged about a common second running wheel horizontal axis (2.12) and axially spaced apart, wherein the second active wheel unit (2.2) has a second bogie (2.21) and a second drive wheel (2.24), wherein the second bogie (2.21) is rotatably mounted on the chassis (3) about a second vertical axis (2.22) and a second steering drive (2.23) is assigned to the second bogie (2.21), wherein the second drive wheel (2.24) is rotatably arranged on the second bogie (2.21) about a second drive wheel horizontal axis (2.25) and a second wheel drive (2.26) is assigned to the second drive wheel (2.24), wherein the two second running wheels (2.11) and the second drive wheel (2.24) are22) span a second triangle with respect to each other, wherein the first and second wheel horizontal axes are arranged parallel to each other and the first and second drive wheel units are arranged opposite each other on both sides of the wheel horizontal axes, wherein the control unit is connected to the steering drives and the wheel drives and is configured to generate drive control commands and transmit them to the wheel drives and to generate steering control commands and transmit them to the steering drives. Modular drive and steering system according to claim 1, characterized in that the first drive wheel or the second drive wheel is configured as a double wheel. Modular drive and steering system according to one of the preceding claims. characterized in that the first passive wheel unit and the second passive wheel unit are integrated into each other and that the first two wheels simultaneously form the second two wheels.

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