STEERING CONTROL SYSTEM OF A MULTI-LEVEL VEHICLE

Description

[0001] The invention relates to a steering control system for controlling the steering of a multi-section vehicle with several movably connected vehicle parts, comprising the features of the preamble of claim 1. Accordingly, the steering control system includes a first axle control unit for arrangement in conjunction with a first steerable axle unit and at least one second axle control unit for arrangement in conjunction with at least one second steerable axle unit. Furthermore, the invention relates to a multi-section vehicle with several movably connected vehicle parts and several steerable axle units, as well as such a steering control system. Finally, the invention relates to a method for constructing a steering control system. STATE OF THE ART

[0002] Document DE 10 2017 112 183 A1 discloses a steering control system for steering at least one rear axle of a multi-section vehicle, comprising a first control unit. The first control unit has a first input interface for receiving a front axle steering angle data point and a vehicle speed data point, and includes a setpoint module for determining a first target rear axle steering angle data point based on the vehicle speed data point and the front axle steering angle data point. Furthermore, a second control unit is provided, comprising a second input interface for receiving the front axle steering angle data point and the vehicle speed data point, and including a parallel module for determining a second target rear axle steering angle data point based on the vehicle speed data point and the front axle steering angle data point.An axis-divided control system that can be expanded modularly is not possible due to the rigid structure.

[0003] Document DE 10 2006 037 588 A1 discloses a method for multi-axle steering of multi-section road vehicles with several steerable axle units via output control signals using a steering control system. The calculation of the control signals incorporates online measured vehicle parameters such as vehicle speed and the target trajectory. Lateral deviations between the target trajectory and the actual vehicle position, described by the location of the steering axle centers, which are unavoidable due to disturbances or other influences, are measured and corrected by subordinate control loops at each steering axle. A disadvantage of the described setup is the rigid and non-expandable arrangement of components consisting of several superior and subordinate control elements.

[0004] Further steering control systems are known from EP 1 847 442 A2, DE 10 2010 027 118 A1, EP 3 363 274 A1 and US 2013 / 1 87361 A1, which corresponds to the preamble of claim 1. However, the steering control systems disclosed therein are also rigidly designed and not flexibly expandable. REVELATION OF THE INVENTION

[0005] The object of the invention is to create a steering control system for controlling the steering of a multi-section vehicle with several movably connected vehicle parts and several steerable axle units, which is flexible in its application, in particular without increasing the overall complexity of the system and / or compromising the accuracy and / or safety of the steering control. In particular, a steering control system is to be created that has a modular design and can be used for vehicles with either more or fewer axle units.

[0006] The problem according to the invention is solved by a system with the features of independent claim 1. Furthermore, the problem according to the invention is solved by a multi-section vehicle with the features of independent claim 9 and a method for constructing a steering control system with the features of independent claim 10.

[0007] According to the invention, it has been recognized that steering control systems are necessary for the construction of so-called trams on wheels. These systems must be able to individually control the axle control units on the steerable axle units, ensuring that each axle unit assumes the correct steering angle position for a given trajectory. For this to work, the axle control unit of each controlled axle unit must be supplied with specifically calculated steering angle data, while simultaneously transmitting current axle information from the axles to a control unit. The aim is to provide a steering control system that can be operated independently of the number of steerable axle units and without significant adaptation effort for trams on wheels of varying lengths with a variable number of vehicle sections. Tram systems, in particular, have very different regional requirements, which can also vary depending on the route or the time of day.Therefore, a high degree of flexibility is required, especially in such vehicle systems. The steering control system according to the invention can guarantee precisely this flexibility, particularly without compromising vehicle safety.

[0008] According to the invention, the steering control system has a central control module which is connected to the several axle control units via a common data line for exchanging steering angle data, wherein the axle control units have data interfaces for communication via the data line which are designed for the transmission of identical data formats, whereby the steering control system can be modularly constructed with a variable number of integrable axle control units.

[0009] The steering control system further developed according to the invention offers the advantage that the essential control tasks can be processed locally in the central control module, while the axle control units, which are arranged in conjunction with the axle units, essentially process peripheral information directly related to the sensors and actuators of the axle unit itself. The actual control information can thus be generated in the central control module in order to ultimately supply the axle control units with the steering information. At the same time, the axle control units can transmit the respective current axle control information to the central control module.

[0010] The key advantage is also achieved by the fact that the axle control units can be operated independently of one another, since they essentially only exchange data with the central control module. Therefore, the number of axle control units ultimately connected to the system is irrelevant to the function of the steering control system. In other words, in the simplest case, a steering control system according to the invention can be built from a central control module and one or more axle control units, each assigned to a specific axle. To create this comparatively simple architecture within the steering control system, the data interfaces of the axle control units are designed to be identical or the same, so that the central control module does not need to be adapted to the number of axle units.The data exchange between the central control module and the axle control units can be standardized in such a way that the steering control system can be expanded or reduced as needed with regard to the number of axle control units. In particular, due to their identical design, the data interfaces, in conjunction with the data line and especially with the central control module, do not require any assigned slots in a mechanical-technical sense or any separate programming in an electrical sense.

[0011] The data interfaces, which are identical to one another according to the invention, are designed such that the data formats of the data interfaces of the multiple axis control units can be read by each individual axis control unit. Individual or all data interfaces can be identical to one another, and in particular, identical. That is, the data interfaces of the multiple axis control units can be identical or identical in terms of construction, geometry, mechanics, electrical components, and / or information technology. For example, the data interfaces can have the same pin assignment of a connector unit and an identical, and in particular, identical geometry, so that the connector units are interchangeable.However, particularly with regard to electrical aspects, the data interfaces are designed to be identical to each other, so that the multiple data interfaces of the multiple axle control units can exchange identical data formats with the central control module. This enables the modular design of the steering control system with a variable number of axle control units and a correspondingly variable number of axle units. Consequently, a vehicle can be built with varying numbers of components, and components can be easily removed or added, for example, to quickly adapt the tram to current transport needs.

[0012] According to one embodiment, the axle control units are identical to one another in terms of construction, geometry, mechanics, electrical components, and / or information technology. The axle control units can be used for a front axle unit, a middle axle unit, or a rear axle unit with respect to a vehicle's direction of travel, and the axle unit is, in particular, actively steered. The axle unit can also be equipped with a steering unit, which is controlled, for example, by a driver or an autonomous driving system of the vehicle. The axle control unit of such an axle unit with a steering unit can be identical in one of the aforementioned ways to axle control units without a steering unit. However, the axle control unit of an axle unit with a steering unit can also include additional functions. These additional functions can, in particular, be selectively activated or deactivated, for example, by...depending on whether the axle unit is intended to function as an axle unit with or without a steering unit.

[0013] According to one embodiment of the steering control system, axle-specific steering angle actual data is transmitted from each axle control unit to the central control module, and / or axle-specific steering angle target data is transmitted from the central control module to each of the axle control units. According to a particularly advantageous aspect of the invention, steering angle information is generally exchanged mainly or exclusively via the data lines, specifically the actual steering angle data from the axle control units to the central control module and / or the steering angle target data from the central control module to the axle control units. Of course, ancillary data or information can also be transmitted, particularly if the communication system via the data line is based on a bus system and the individual axle control units need to be addressed with these associated data sequences.

[0014] The central control module can have a control interface through which vehicle driving data is transmitted to the central control module, the driving data including at least a vehicle speed, a direction of travel, and / or steering information. The steering information can be provided, in particular, by a steering system operated by a driver and / or by an autonomous driving system of the vehicle. The control of the axle control units by the central control module is based, in particular, on and / or dependent on the driving data transmitted by the vehicle to the central control module via the control interface. For example, a steering angle adjustment calculated by the central control module is smaller at higher vehicle speeds than at lower vehicle speeds.

[0015] Steering information can be provided by a steering system, in particular a steer-by-wire system, by means of which the driver operates a steering wheel. The steering information is provided by a steering sensor and transmitted to the central control module via the control interface. The steering information provided by a driver or an autonomous driving system can be accessed directly at an axle unit. According to one embodiment, this steering information is first transmitted to the central control module to then steer the axle unit on which the steering system is located. The other axles are controlled in the same way with corresponding information.In other words, in this embodiment, a multi-unit vehicle is no longer steered at, for example, a front axle unit by means of steering information from a driver or an autonomous driving system. Instead, the steering information reaches each individual axle unit via the central control module, so that a target steering angle, calculated by the central control module, is executed for each axle unit based on this steering information. However, it is also possible for the steering information to be processed directly by the corresponding axle control unit of the axle unit with the steering system, and for this axle unit to be steered directly according to the steering information. Simultaneously, the steering information is transmitted to the central control module, which also processes the steering information and outputs corresponding steering angle data to the other axle control units.Alternatively, steering information from a steer-by-wire system or a steering wheel can be fed directly to the central control module. The central control module processes the steering angle information and transmits corresponding steering angle data to the individual axle control units.

[0016] The central control module can output data to a vehicle control unit or its subsystems via the control interface or another interface. For example, status information and / or error messages can be sent from the central control module to the vehicle or its control unit. Furthermore, the central control module can issue braking, speed, and / or performance requests, which are processed, for example, within the vehicle's brake and / or engine control system. The central control module can thus also influence the overall control of the vehicle. For example, in the event of a fault, the central control module can impose a speed limit.

[0017] According to one embodiment, the steerable axle units have axle devices comprising at least one steering actuator, at least one sensor, at least one hydraulic unit, and / or at least one electronic axle safety device, wherein the axle control unit of the steerable axle unit autonomously controls and / or monitors the axle devices. Information exchange, for example, between sensors and actuators of the axle unit itself, takes place within the axle unit with the axle control unit, without this information necessarily having to be transmitted to the central control module via the data line. However, the axle control unit determines actual data, in particular the current steering angle, which is provided to the central control module via the data line.For example, if the axle control unit receives a target steering angle data set by the central control module, it can activate the axle unit by communicating with its sensors and actuators, particularly the hydraulic unit and / or steering actuator. This allows the axle control unit to then transmit the resulting actual steering angle information back to the central control module via its data interface. This creates a control loop in which the axle control units regularly query the actual steering angle data, which is then processed by a corresponding program in the central control module. The control loop also includes outputting target steering angle data to the axle control units to determine correction values ​​and implement appropriate adjustments.The periodically repeated determination of correction values ​​and triggering of such corrections ultimately leads to the execution of the corresponding steering angle setting, which is individually adjusted for each axle unit, with the settings being monitored by the central control module.

[0018] To increase functional reliability, the axle control unit is designed to have at least two redundant and operational processing units. In particular, the central control module may also have at least two, and preferably three, redundant and operational central processing units. Alternatively or additionally, to increase the functional reliability of the steering control system, the data line and the respective data interfaces of the axle control units may have redundant data transmission means. The system is thus designed in such a way that comparative analyses can be performed with respect to the central processing units of the central control module and the processing units of the axle control units.If the information obtained from the individual processing units or from the individual central processing units differs from one another, the plausibility of the information can be checked again, which is particularly possible with three redundantly configured and operated units. It is especially advantageous if the processing units of the axle control unit or the central processing units of the central control module have different hardware configurations in order to exclude systemic error influences. As a result, a steering control system can be provided that meets the ASIL-D standard.

[0019] To increase the operational reliability of the steering control system, the central control module includes, in particular, one or more monitoring means for verifying the plausibility of the actual steering angle data transmitted by the axle control units. Likewise, it is possible that each axle control unit preferably includes one or more monitoring means for verifying the plausibility of the target steering angle data transmitted by the central control module. The monitoring means can include microcontrollers in which comparison data is stored, and the microcontrollers compare the actual steering angle data and the target steering angle data with the comparison data.For example, if steering angle information from the actual data or the target data falls outside a plausibility range, a comparison can be made with the monitoring device to the other information, insofar as it is provided by the other computing units of the axle control unit or by the other central computing units of the central control module.

[0020] Vehicle components are typically connected to each other by joints. These joints may have joint control units that are also connected to the data line and can exchange data with the central control module. In particular, the joints may have angle sensors that acquire joint angle information and transmit it to the central control module. To further increase operational reliability, the joint angle information can also be acquired independently by the joint control unit. Specifically, a plausibility check of the joint angle information acquired in this way can be performed against the joint angle information of the central control module. Furthermore, it is also possible to feed the joint angle information from the joints between the vehicle components to the central control module to determine the target steering angle data.

[0021] According to the invention, the central control module comprises a software-based, vehicle-specific motion model configured to determine the axle-specific steering angle target data for output to each of the axle control units based on the vehicle-specific motion model. The vehicle-specific motion model is based on vehicle data, in particular the dimensions and / or mass of the vehicle, on axle data such as axle loads and / or the number of steerable and / or non-steerable axle units, and / or on joint data, e.g., the joint angles and / or the number of joints.

[0022] The invention further relates to a multi-section vehicle with several movably connected vehicle parts and several steerable axle units, and with a steering control system for controlling the steering of the multi-section vehicle, wherein the steering control system comprises a first axle control unit arranged in conjunction with a first steerable axle unit, and at least a second axle control unit arranged in conjunction with at least a second steerable axle unit.In particular, the steering control system has a central control module which is connected to the several axle control units via a common data line for the exchange of steering angle data, wherein the axle control units have data interfaces for communication via the data line which are designed for the transmission of identical data formats, thus making the steering control system modular with a variable number of integrable axle control units.

[0023] According to the invention, the central control module comprises a software-based, vehicle-specific motion model configured to determine the axle-specific steering angle target data for output to each of the axle control units based on the vehicle-specific motion model. The vehicle-specific motion model is based on vehicle data, in particular the dimensions and / or mass of the vehicle, on axle data such as axle loads and / or the number of steerable and / or non-steerable axle units, and / or on joint data, e.g., the joint angles and / or the number of joints.

[0024] With regard to preferred embodiments of the multi-section vehicle, the descriptions of the steering control system according to the invention apply accordingly.

[0025] The invention further relates to a method for constructing a steering control system designed to control the steering of a multi-section vehicle with several movably connected vehicle parts and several steerable axle units, wherein the method comprises at least the following steps: modular arrangement of a first axle control unit in conjunction with a first steerable axle unit, modular arrangement of at least one second axle control unit in conjunction with at least one second steerable axle unit, wherein the axle control units are designed to be interchangeable with respect to their connection to a data line, and wherein a central control module is provided which exchanges steering information with the axle control units via the data line, wherein, upon commissioning of the steering control system, the axle control units are operated independently of one another and independently of their number.by communicating with a central control module via the common data line.

[0026] According to the invention, the central control module comprises a software-based, vehicle-specific motion model with which the axle-specific steering angle target data are determined for output to each of the axle control units based on the vehicle-specific motion model. The vehicle-specific motion model is based on vehicle data, in particular the dimensions and / or mass of the vehicle, on axle data such as axle loads and / or the number of steerable and / or non-steerable axle units, and / or on joint data, e.g., the joint angles and / or the number of joints.

[0027] The method is characterized in particular by the fact that the axle control units communicate exclusively with the central control module. This means that, unlike in the prior art, the axle control units do not directly exchange information with each other for steering the axle units and use this information directly for steering the axle units. Rather, information provided by the axle control units is merely processed in the central control module or forwarded by it for processing. Simultaneously, the axle units use only the data provided by the central control module for steering the axle units.

[0028] Furthermore, it is provided that axle-specific steering angle actual data is transmitted from each of the axle control units to the central control module and / or that axle-specific steering angle target data is transmitted from the central control module to each of the axle control units.

[0029] Within the scope of the invention, the method can in particular provide that the vehicle parts are connected to each other via joints, wherein the joints each have joint control devices that transmit joint data to the central control module, which includes at least one of the following information: steering angle data, damping data, articulation angle data, lateral offset data, lateral force data.

[0030] With regard to preferred embodiments of the method according to the invention, the descriptions of the steering control system according to the invention and the multi-section vehicle apply accordingly.

[0031] Advantageous embodiments of the invention are described in the claims, the description, and the drawings. The advantages of features and combinations of features mentioned in the description are merely examples and can have an effect alternatively or cumulatively, without necessarily requiring that the advantages be achieved by embodiments of the invention. The features mentioned in the claims and the description are to be understood with regard to their number as meaning that exactly this number or a greater number than the stated number is present, without the need for an explicit use of the term "at least." Thus, for example, if a data interface is mentioned, this is to be understood as meaning that exactly one data interface, two data interfaces, or several data interfaces are present.These features may be supplemented by other features or may be the only features comprising the respective product. The reference numerals included in the claims do not constitute a limitation of the scope of the subject matter protected by the claims. They serve only to make the claims easier to understand. PREFERRED EXAMPLES OF THE INVENTION

[0032] Further measures improving the invention are described in more detail below, together with a description of preferred embodiments of the invention, with reference to the figures. The figures show: Figure 1 is a schematic view of a vehicle with multiple axle units and a steering control system for controlling the axle units; Figure 2 is a perspective view of an axle unit with an axle control unit; Figure 3 is a perspective view of an axle unit with an axle control unit and a steering device; and Figure 4 is another schematic view of the vehicle with a steering control system featuring a central control module with, by way of example, only one axle control unit.

[0033] The in Figure 1 The vehicle 100 shown is designed in the style of a so-called tram on wheels. The vehicle 100 comprises several vehicle sections 10, and the individual vehicle sections 10 have one or more axle units 11. The vehicle sections 10 are connected to one another by means of joints 29. Such vehicles 100 can be particularly long and are constructed from several vehicle sections 10.

[0034] A schematic representation shows a steering control system 1, which serves to link the several axle control units 12 to the axle units 11. When the vehicle 100 is set in motion, each axle unit 11 must assume a previously calculated steering angle in order to travel along a desired trajectory without individual axle units 11 deviating from the trajectory, which in the worst case would render the vehicle inoperable. A control system for the vehicle 100 is necessary for this purpose, the structure of which is described in more detail below.

[0035] The steering control system 1 has a central control module 13, which is connected to the axle control units 12 of the axle units 11 via a common data line 14 for the exchange of steering angle data. The data line 14 has several parallel data transmission means 28 to provide redundancy. To further increase operational reliability, the central control module 13 has several independent central processing units 27, which are shown only schematically.

[0036] Driving data 19, such as the direction of travel and the speed of the vehicle 100, can be supplied to the central control module 13 via a control interface 18. Steering information 20, provided by a steering device 21, is also supplied to the central control module 13 and also constitutes driving data. The steering device 21 can be operated by a driver of the vehicle 100 in a manner known per se, or the steering device 21 may be part of an autonomous driving system of the vehicle 100.

[0037] The steering information exchanged via data line 14 between the axle control units 12 and the central control module 13 concerns actual steering angle data transmitted from the axle control units 12 to the central control module 13, and the data concerns target steering angle data 17 transmitted from the central control module 13 to the axle control units 12. Furthermore, the joints 29 have joint control devices 30, which also exchange data with data line 14 and thus with the central control module 13.

[0038] The Figures 2 and 3 show examples of axle units 11, where the axle unit 11 is configured according to the Figure 3 a steering device 21, and thereby differs from the axle unit 11 according to Figure 2 differs.

[0039] The axle units 11 include, as an essential component, an axle control unit 12, which has a data interface 15. The data interface 15 is connected to the data line 14 for data transmission. The axle control units 12 are connected to components of the axle unit 11, of which several sensors and actuators are shown (this list is not exhaustive). For example, the axle units 11 have steering actuators 22, which can be controlled via the axle control unit 12. For example, the current steering angle of the axle unit 11 can be detected by sensors 23 and processed by the axle control unit 12. Other components of the axle units 11 include, for example, a hydraulic unit 24, which can be used to drive the steering actuators 22.

[0040] The axle control unit 12 is connected to the data interface 15, which supplies the steering angle data to the central control module (not shown) via the data line 14 and receives corresponding steering angle data from the central control module.

[0041] Figure 3 Figure 1 shows an axle unit 11, which can be located, for example, at the front or rear end of the vehicle 100. The axle unit 11 has a steering device 21 that transmits steering information 20 to the axle control unit 12. This allows a driver or an autonomous driving system to specify a path along which the vehicle 100 should travel.

[0042] Figure 4Finally, a further schematic view shows the steering control system 1 in conjunction with the vehicle 100. The vehicle 100 is shown with the several axle units 11, with one axle unit 11 and its associated components shown schematically enlarged. Above the vehicle 100, the central control module 13 is shown, with a data line 14 between the central control module 13 and the axle unit 11 schematically indicated. The depicted axle unit 11 is present multiple times in order to form the steering control system 1 together with the central control module 13.

[0043] As an essential electronic component, the axle unit 11 includes the axle control unit 12, which is connected to the data line 14 via the data interface 15.

[0044] In the illustrated embodiment, the central control module 13 is based on three central processing units 27, which can be structurally identical or, in particular, each have different hardware. The central processing units 27 are operated side by side and, in particular, independently of one another. With different hardware, operational reliability can be further increased, as the software-based, vehicle-specific motion model can be installed and operated on each of the central processing units 27. Thus, with three central processing units 27 and the associated redundancy, a very high level of operational reliability is achieved for the central control module 13. According to the invention, the central control module 13 can also be designed and built on a single central processing unit 27, on two central processing units 27, or on more than three central processing units 27.

[0045] The axle unit 11 includes the axle control unit 12, which is exemplified by two computing units 26 that can be operated redundantly in the same manner. The two computing units 26 shown for forming the axle control unit 12 can also have different hardware configurations or be identical. If steering information is exchanged with the central control module 13 via the data line 14, the plausibility of the exchanged data can be monitored by an axle operational safety device 25.

[0046] The axle unit 11, for example, has a steering actuator 22 for performing the steering movement of the wheels, a sensor 23 for detecting a current steering angle of the wheels and a hydraulic unit 24, wherein preferably all peripheral devices are controlled by the axle control unit 12.

[0047] The invention is not limited in its implementation to the preferred embodiment described above. Rather, a number of variants are conceivable, which utilize the solution presented even in fundamentally different designs. All features and / or advantages arising from the claims, the description, or the drawings, including design details or spatial arrangements, can be essential to the invention, both individually and in various combinations. Reference symbol list:

[0048] 100 vehicles 1. Steering control system 10 Vehicle component 11 Axle unit 12 Axle control unit 13 Central control module 14 Data line 15 Data interface 16 Actual steering angle data 17 Target steering angle data 18 Control interface 19 Driving data 20 Steering information 21 Steering device 22 Steering actuator 23 Sensor 24 Hydraulic unit 25 Axle operational safety device 26 Computing unit 27 Central computing unit 28 Data transmission device 29 Joint 30 Joint control device

Claims

1. Steering control system (1) for controlling steering of a multi-unit vehicle (100) having a plurality of movably interconnected vehicle parts (10) and a plurality of steerable axle units (11), comprising - a first axle control unit (12) for arrangement in connection with a first steerable axle unit (11), and - at least one second axle control unit (12) for arrangement in connection with at least one second steerable axle unit (11), - wherein - the steering control system (1) has a central control module (13) which is connected to the plurality of axle control units (12) via a common data line (14) for exchanging steering angle data, - wherein the axle control units (12) have data interfaces (15) for communication via the data line (14), which interfaces are designed to transmit mutually identical data formats, as a result of which the steering control system (1) can have a modular design with a variable number of axle control units (12) which can be integrated, - wherein axle-specific steering angle actual data (16) can be transmitted from each of the axle control units (12) to the central control module (13), and axle-specific steering angle target data (17) can be transmitted from the central control module (13) to each of the axle control units (12), characterized in that the central control module (13) has a software-based vehicle-specific movement model which is designed to determine the axle-specific steering angle target data (17) for outputting to each of the axle control units (12) on the basis of the vehicle-specific movement model, wherein the vehicle-specific movement model is based on vehicle data, at least comprising: - the dimensions and / or mass of the vehicle (100), - the axle data, at least comprising axle loads and / or the number of steerable and / or non-steerable axle units (11), and / or - joint data comprising joint angles and / or the number of joints (29).

2. Steering control system (1) according to claim 1, characterized in that the axle control units (12) are structurally and / or electronically identical to one another and / or can be operated independently of one another.

3. Steering control system (1) according to either of the preceding claims, characterized in that - the central control module (13) has a control interface (18) via which driving data (19) of the vehicle (100) can be transmitted to the central control module (13), wherein the driving data (19) comprise at least a driving speed, a driving direction and / or steering information (20), wherein optionally a steering device (21) controlled by a driver and / or an autonomous driving device of the vehicle (100) provides the steering information (20); and / or - the central control module (13) has a control interface for transmitting central control module data to a vehicle controller, wherein the central control module data comprise status information and / or braking, speed and / or power information.

4. Steering control system (1) according to any of the preceding claims, characterized in that the steerable axle units (11) have axle devices comprising at least one steering actuator (22), at least one sensor (23), at least one hydraulic unit (24) and / or at least one electronic axle operation safety device (25), wherein the axle control unit (12) of the steerable axle unit (11) autonomously controls and / or monitors the axle devices.

5. Steering control system (1) according to any of the preceding claims, characterized in that the axle control unit (12) has at least two computing units (26) which are designed to be redundant with respect to one another, and / or the central control module (13) has at least two and preferably three central computing units (27) which are designed to be redundant with respect to one another.

6. Steering control system (1) according to any of the preceding claims, characterized in that the data line (14) and the respective data interfaces (15) of the axle control units (12) have data transmission means (28) which are designed to be redundant with respect to one another.

7. Steering control system (1) according to any of the preceding claims, characterized in that the central control module (13) has at least one monitoring means, by means of which the plausibility of the steering angle actual data (16) transmitted by the axle control units (12) can be monitored, and / or the axle control units (12) have at least one monitoring means, by means of which the plausibility of the steering angle target data (17) transmitted by the central control module (13) can be monitored.

8. Steering control system (1) according to any of the preceding claims, characterized in that the vehicle parts (10) are connected to one another via joints (29), wherein the joints (29) have joint control devices (30) which are connected to the data line (14) and are in data exchange with the central control module (13), in particular in order to transmit joint angle information, which can be detected by means of angle sensors at the joints (29), to the central control module (13).

9. Multi-unit vehicle (100) comprising a plurality of movably interconnected vehicle parts (10) and a plurality of steerable axle units (11), and comprising a steering control system (1) for controlling the steering of the multi-unit vehicle (100), wherein the steering control system (1) has: - a first axle control unit (12) arranged in connection with a first steerable axle unit (11), and - at least one second axle control unit (12) arranged in connection with at least one second steerable axle unit (11), wherein - the steering control system (1) has a central control module (13) which is connected to the plurality of axle control units (12) via a common data line (14) for exchanging steering angle data, - wherein the axle control units (12) have data interfaces (15) for communication via the data line (14), which interfaces are designed to transmit mutually identical data formats, as a result of which the steering control system (1) has a modular design with a variable number of linkable axle control units (12) which can be integrated, - wherein axle-specific steering angle actual data (16) can be transmitted from each of the axle control units (12) to the central control module (13), and axle-specific steering angle target data (17) can be transmitted from the central control module (13) to each of the axle control units (12), characterized in that the central control module (13) has a software-based vehicle-specific movement model which is designed to determine the axle-specific steering angle target data (17) for outputting to each of the axle control units (12) on the basis of the vehicle-specific movement model, wherein the vehicle-specific movement model is based on vehicle data, at least comprising: - the dimensions and / or mass of the vehicle (100), - the axle data, at least comprising axle loads and / or the number of steerable and / or non-steerable axle units (11), and / or - joint data comprising joint angles and / or the number of joints (29).

10. Method for constructing a steering control system (1) which is designed to control the steering of a multi-unit vehicle (100) having a plurality of movably interconnected vehicle parts (10) and a plurality of steerable axle units (11), wherein the method comprises at least the following steps: - modular arrangement of a first axle control unit (12) in connection with a first steerable axle unit (11) and - modular arrangement of at least one second axle control unit (12) in connection with at least one second steerable axle unit (11), - wherein the axle control units (12) are designed to be interchangeable with one another with regard to their connection to a data line (14) and - wherein a central control module (13) is configured which exchanges steering information with the axle control units (12) via the data line (14), wherein - when the steering control system (1) is put into operation, the axle control units (12) are operated independently of one another and independently of their number by communicating with the central control module (13) via the common data line (14), - axle-specific steering angle actual data (16) are transmitted from each of the axle control units (12) to the central control module (13), and axle-specific steering angle target data (17) are transmitted from the central control module (13) to each of the axle control units (12), - wherein the central control module (13) has a software-based vehicle-specific movement model, by means of which the axle-specific steering angle target data (17) for outputting to each of the axle control units (12) are determined on the basis of the vehicle-specific movement model, wherein the vehicle-specific movement model is based on vehicle data, at least comprising: - the dimensions and / or mass of the vehicle (100), - the axle data, at least comprising axle loads and / or the number of steerable and / or non-steerable axle units (11), and / or - joint data comprising joint angles and / or the number of joints (29).

11. Method according to claim 10, characterized in that the axle control units (12) communicate exclusively with the central control module (13).

12. Method according to any of claims 10 to 11, characterized in that the vehicle parts (10) are connected to one another via joints (29), wherein the joints (29) each have joint control devices (30) which transmit joint data to the central control module (13), which data comprise at least one of the following pieces of information: steering angle data, damping data, articulation angle data, lateral offset data, lateral force data.