DE102022112684A1 - Method for controlling an autonomous vehicle, computer program product, control unit and autonomous vehicle - Google Patents

Abstract

The invention relates to a method for controlling an autonomously driving vehicle (1) with a drive unit (2) and a control device (3) for controlling the vehicle (1), with a first vehicle axle (4) with at least two vehicle wheels (5, 6) , which define a first track width S1, and a second vehicle axle (7) running parallel to the first vehicle axle (4) with at least two vehicle wheels (8, 9) which define a second track width S2, at least the vehicle wheels (5, 6, 8 , 9) can be steered on one of the vehicle axles (4,7) by the control device (3), and two vehicle wheels (5,6,8,9) on one of the vehicle axles (4,7) can be driven by the drive unit (2).

Description

The present invention relates to a method for controlling an autonomously driving vehicle with a drive unit and a control device for controlling the vehicle, with a first vehicle axle with at least two vehicle wheels that define a first track width S, and a second vehicle axle running parallel to the first vehicle axle with at least two vehicle wheels that define a second track width S, wherein at least the vehicle wheels on one of the vehicle axles can be steered by the control device, and two vehicle wheels on one of the vehicle axles can be driven by the drive unit. The invention further relates to a computer program product, a control unit and an autonomously driving vehicle.

Electric motors are increasingly being used to drive motor vehicles in order to create alternatives to combustion engines that require fossil fuels. Significant efforts have already been made to improve the suitability of electric drives for everyday use and to offer users the usual driving comfort.

In this context, wheel drive modules are also generally known from the prior art. The integration of the electric drive into the individual wheels and the combination of individually driven and steerable wheels (wheel modules) opens up new possibilities for vehicle maneuverability in confined situations. This is made possible by an electric steering actuator (steering actuator) integrated into the wheel drive module, which, for example, enables a steering angle of up to 90° in any direction. In other words, very large steering angles can be achieved using such a wheel drive module, which can be used for maneuvering and parking, for example.

The combination of this extreme mobility with the electric drive makes such a wheel drive module particularly suitable for motor vehicles that are primarily used in city traffic, including self-driving motor vehicles for city traffic. An autonomous motor vehicle or self-driving motor vehicle is a motor vehicle that can drive, steer and park without the influence of a human driver (highly automated driving or autonomous driving).

A wheel drive module of the type mentioned is, for example, from the publication DE 10 2017 106 826 A1 known. This publication shows a wheel drive module for a motor vehicle, with a wheel and a wheel guide for guiding the wheel. The wheel guide in turn comprises (i) a wheel carrier unit for supporting the wheel, which includes an electric drive machine and a braking device, (ii) a wheel fork carrying the wheel carrier unit, (iii) a spring-damper unit (sometimes also simply referred to as a spring strut), (iv) at least part of a storage unit for supporting the wheel module on a vehicle body of the motor vehicle and (v) a steering actuator for adjusting the steering angle of the wheel via the wheel fork. A connection to the body/vehicle body takes place via a storage unit designed as a strut bearing. The publication also shows a motor vehicle with four such wheel modules.

In addition to increasing electrification of drive trains in motor vehicles, motor vehicles are also becoming increasingly autonomous. Particularly with the advent of automated electric vehicles and new complete vehicle concepts, so-called people movers are increasingly being used in urban areas, which are designed as autonomous motor vehicles. An autonomous motor vehicle or self-driving motor vehicle is a motor vehicle that can drive, steer and, for example, park without the influence of a human driver (highly automated driving or autonomous driving). A special form of autonomous motor vehicle is the autonomous passenger transport vehicle, which is also referred to as a people mover or autonomous people mover. In this context, autonomous means that none of the people being transported controls the vehicle, but rather that the passenger transport vehicle is self-controlled or automatically controlled. The people transported are usually “just” passengers/passengers.

In this context, various concepts for controlling vehicle speed and vehicle acceleration have also become known. DE102011080761A1 describes, for example, a method for determining a speed warning for a driver of a motor vehicle, in which a control unit calculates a curvature of the route based on map data for a predeterminable part of the route ahead and uses this to calculate and output a maximum speed as a recommendation. DE102017212899A1 describes a method for calculating the trajectory/trajectory planning of a motor vehicle.

There is a continuing need to expand the areas of application of such people movers. For example, it is generally known that the platform of an autonomous driving vehicle Motor vehicle to use it to tow truck trailers, such as in the DE1752295U is described. Here, an autonomously driving substructure is connected to a semi-trailer using a defined coupling point. A similar concept is in the DE102019119074A1 shown. The document US 2018/0129958 A discloses a modular electric vehicle with interchangeable vehicle modules, allowing a user to disassemble and reassemble the vehicle for different use cases.

Another autonomous transport system is known from the company Udelv, among others (https://www.udelv.com/). The vehicle is suitable for bringing goods or packages to the recipient autonomously. The vehicle can be loaded centrally in a logistics center and bring the individual packages to different recipients, or the vehicle collects packages or goods from different senders and brings them to a central logistics center. A hybrid of the scenarios mentioned above is also conceivable.

Depending on the load, such vehicles for transporting goods can have a high center of gravity and therefore have a high tendency to tip over, especially if the track width of the vehicle is chosen to be comparatively narrow in order to ensure good passability of the vehicle even in narrow or narrow urban driving environments to be able to realize. In today's vehicles, the chassis is usually designed taking all driving situations into account in such a way that the vehicle is prevented from tipping over.

However, with an autonomous transport vehicle, the driving situations that arise are very difficult to estimate because, among other things, the vehicle is loaded by different senders and the weight of the respective package is not always known in advance and the sender can place the package in a free compartment independently. This allows, for example, a heavy package to be placed in an upper compartment, thereby increasing the center of gravity of the vehicle. Due to the application, there is usually no need to check that the vehicle has been loaded correctly by a trained driver. This lack of verification must be compensated for in an autonomous vehicle.

It is therefore the object of the invention to provide a method for controlling an autonomously driving vehicle, in particular for an autonomous transport vehicle, which enables safe operation of the vehicle taking into account the current loading status. It is also the object of the invention to realize an improved computer program product, an optimized control device and an improved autonomously driving vehicle.

1. a) Ermittlung des Gewichts m des Fahrzeugs;
2. b) Ermittlung der Lage des Schwerpunkts des Fahrzeugs in einer senkrecht zur Schwerkraftrichtung verlaufenden Ebene;
3. c) Ermittlung der Lage des Schwerpunkts des Fahrzeugs in Schwerkraftrichtung;
4. d) Ermittlung einer zulässigen Querbeschleunigung q_max für das Fahrzeug und Speicherung der zulässigen Querbeschleunigung q_max in der Steuereinrichtung;
5. e) Ermittlung von Informationen aus einer Trajektorie (10), die eine Ist-Fahrzeuggeschwindigkeit v_ist, eine Beschleunigung a_x in Längsrichtung des Fahrzeugs (1) sowie einen Lenkwinkel α repräsentieren und welche zur
6. f) Ermittlung einer Ist-Querbeschleunigung q_ist des Fahrzeugs verwendet werden;
7. g) Vergleich der Ist-Querbeschleunigung q_ist des Fahrzeugs mit der zulässigen Querbeschleunigung q_max und bei Vorhandensein der Bedingung, dass die Ist-Querbeschleunigung q_ist des Fahrzeugs größer ist als die zulässige Querbeschleunigung q_max;
8. h) Ermittlung einer korrigierten Beschleunigung a_korr zur Reduzierung der Ist-Fahrzeuggeschwindigkeit v_ist.

This object is achieved by a method for controlling an autonomously driving vehicle with a drive unit and a control device for controlling the vehicle, with a first vehicle axle with at least two vehicle wheels that define a first track width S, and a second vehicle axle running parallel to the first vehicle axis at least two vehicle wheels that define a second track width S, wherein at least the vehicle wheels on one of the vehicle axles can be steered by the control device, and two vehicle wheels on one of the vehicle axles can be driven by the drive unit, comprising the following steps:

1. a) Determination of the weight m of the vehicle;
2. b) determining the position of the vehicle's center of gravity in a plane perpendicular to the direction of gravity;
3. c) Determination of the position of the vehicle's center of gravity in the direction of gravity;
4. d) determining a permissible lateral acceleration q _max for the vehicle and storing the permissible lateral acceleration q _max in the control device;
5. e) Determination of information from a trajectory (10), which _represents an actual vehicle speed v, an acceleration a _x in the longitudinal direction of the vehicle (1) and a steering angle α and which
6. f) Determination of an actual lateral acceleration q of the vehicle _can be used;
7. g) Comparison of the actual lateral acceleration q _is of the vehicle with the permissible lateral acceleration q _max and in the presence of the condition that the actual lateral acceleration q _is of the vehicle is greater than the permissible lateral acceleration q _max ;
8. h) Determination of a corrected acceleration a _korr to reduce the actual vehicle speed v _ist .

This can be used to provide a method which, after loading the vehicle, determines the position of the center of gravity of the vehicle and adaptively determines the permissible lateral acceleration of the vehicle, as well as monitors and limits the trajectory planning of the autonomous driving function so that a predetermined lateral acceleration is not exceeded. This ensures that even if the vehicle is unfavorably loaded safe operation is ensured, especially when cornering.

The invention describes a method for operating an autonomous vehicle, this method being particularly suitable for an autonomous transport system, since this ensures safe operation of the vehicle regardless of the load.

First, the individual elements of the claimed subject matter of the invention are explained in the order in which they are mentioned in the claim sentence and particularly preferred embodiments of the subject matter of the invention are described below.

A drive unit can in particular include an electrical machine.

According to a further preferred further development of the invention, it can also be provided that the first vehicle axle has/has a first electrically operable drive train and/or the second vehicle axle has/has a second electrically operable drive train and the first electrically operable drive train and the second electrically operable drive train are highly preferred are essentially identical.

An electrically operable drive train comprises an electric machine and preferably a transmission arrangement coupled to the electric machine. The gear arrangement and the electrical machine form a structural unit. This can be formed, for example, by means of a drive train housing in which the transmission arrangement and the electric machine are accommodated together.

Such electrical machines are used to convert electrical energy into mechanical energy and/or vice versa, and generally include a stationary part called a stator, stand or armature and a part called a rotor or rotor and arranged to be movable relative to the stationary part. In the case of electrical machines designed as rotary machines, a distinction is made in particular between radial flux machines and axial flux machines. A radial flux machine is characterized in that the magnetic field lines in the air gap formed between the rotor and stator extend in the radial direction, while in the case of an axial flux machine the magnetic field lines in the air gap formed between the rotor and stator extend in the axial direction. In connection with the invention, the electrical machine can be designed both as an axial flux machine and as a radial flux machine.

In particular, the electric machine is dimensioned such that vehicle speeds greater than 50 km/h, preferably greater than 80 km/h and in particular greater than 100 km/h can be achieved. The electric motor particularly preferably has a power greater than 30 kW, preferably greater than 50 kW and in particular greater than 120 kW. It is further preferred that the electric machine provides speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, most preferably greater than 12,500 rpm.

The transmission arrangement of the electrically operable drive train can in particular be coupled to the electric machine, which is designed to generate a drive torque for the motor vehicle. The drive torque is particularly preferably a main drive torque, so that the motor vehicle is driven exclusively by the drive torque. The gear arrangement is preferably designed as a planetary gear.

According to an advantageous embodiment of the invention, it can be provided that the vehicle wheels of the first vehicle axle and the second vehicle axle are designed to be steerable, whereby the maneuverability of the vehicle can be further improved.

In a likewise preferred embodiment variant of the invention, it can also be provided that the vehicle wheels of a vehicle axle can each be driven by an electric machine, whereby the driving dynamics and driving stability of the vehicle can be further improved.

It can also be advantageous to further develop the invention in such a way that an actively steerable and driven vehicle wheel, an electric machine, a steering actuator and a braking device each form a wheel drive module. In this context, it is advantageous if the electrical machine is designed as a radial flux machine. In this context, it is also particularly preferred that the vehicle has at least four, preferably identical, wheel drive modules, which on the one hand allows the modularity of the vehicle to be further improved and, on the other hand, the driving characteristics of the vehicle can be further optimized.

A wheel drive module includes in particular an electric wheel hub drive. Such electric wheel hub drives are comparatively small compared to cars due to the space available and the size gen) driving dynamics requirements are well suited for use in commercial vehicles. In addition to the wheel hub drive, a wheel drive module can also, for example, have power electronics for powering the wheel hub drive, a wheel bearing, a sensor for measuring the torque, a sensor for measuring the speed, a sensor for measuring weight, a sensor for measuring the temperature and / or a sensor for measuring noise include. A sensor for weight measurement can also be implemented by or in the air spring of an air suspension system of the motor vehicle.

According to an advantageous embodiment of the invention, it can be provided that steps a)-d) are determined before the vehicle begins to travel so as not to allow a potentially unstable driving situation at any phase of the moving operation along the trajectories.

According to a further preferred development of the invention, it can also be provided that the vehicle wheels are operatively connected to a sensor system for determining the weight m of the vehicle, in which the weight force of the vehicle acting on each of the vehicle wheels is determined, whereby a particularly precise weight measurement before and can also be made possible while driving.

Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the control device comprises a module for trajectory planning and a module for trajectory tracking control, wherein the module for trajectory planning determines the acceleration a _x in the longitudinal direction of the vehicle and the steering angle α and sends it to the module to the trajectory control.

The object of the invention can further be achieved by a computer program product which is stored on a machine-readable carrier, or computer data signal, embodied by an electromagnetic wave, with program code which is suitable for carrying out the method according to claims 1-4.

Furthermore, the object of the invention can be achieved by a control device for controlling an autonomously driving vehicle, comprising a processor and a memory which contains a computer program code, the memory and the computer program code being configured with the processor, the control device for carrying out a method To initiate claims 1-4.

Finally, the object of the invention can also be achieved by an autonomously driving vehicle with a drive unit and a control device for controlling the vehicle, with a first vehicle axle with at least two vehicle wheels that define a first track width S, and a second vehicle axle running parallel to the first vehicle axis with at least two vehicle wheels, which define a second track width S, wherein at least the vehicle wheels on one of the vehicle axles can be steered by the control device, and two vehicle wheels on one of the vehicle axles can be driven by the drive unit, the control device being designed according to claim.

In this context, it can also be advantageous to further develop the invention in such a way that the vehicle has an air suspension system, via which the vehicle wheels are arranged resiliently on a chassis of the vehicle against the direction of gravity. This makes it possible to achieve a particularly high level of driving comfort and ensure constant ground clearance regardless of weight.

According to a further preferred embodiment of the subject matter of the invention, it can be provided that the control device of the vehicle has a first control device for determining the trajectory of the vehicle and a second control device for controlling the air suspension system, which enables a modular structure of the control.

Finally, the invention can also be advantageously designed in such a way that each vehicle wheel has a drive unit assigned to it, whereby the modular structure of the vehicle can be further optimized.

The invention will be explained in more detail below using figures without restricting the general idea of the invention.

• 1 eine erste Ausführungsform eines autonom fahrenden Kraftfahrzeugs in einer schematischen Blockschaltansicht,
• 2 eine zweite Ausführungsform eines autonom fahrenden Kraftfahrzeugs in einer schematischen Blockschaltansicht,
• 3 ein autonom fahrendes Kraftfahrzeug in einer schematischen Seitenansicht,
• 4 eine Steuereinrichtung in einer schematischen Blockschaltansicht,
• 5 eine Ablaufdiagramm eines Verfahrens Verfahren zur Steuerung eines autonom fahrenden Fahrzeugs.

It shows:

• 1 a first embodiment of an autonomously driving motor vehicle in a schematic block diagram,
• 2 a second embodiment of an autonomously driving motor vehicle in a schematic block diagram,
• 3 an autonomously driving motor vehicle in a schematic side view,
• 4 a control device in a schematic block diagram,
• 5 a flowchart of a method for controlling an autonomous vehicle.

The 1-3 show an autonomously driving vehicle 1 with a drive unit 2 and a control device 3 for controlling the vehicle 1. The vehicle 1 has a first vehicle axle 4 with at least two vehicle wheels 5, 6, which define a first track width S1, and one parallel to the first vehicle axle 4 extending second vehicle axle 7 with at least two vehicle wheels 8,9, which define a second track width S2, the vehicle wheels 8,9 being steerable on the vehicle axle 7 by the control device 3. The two vehicle wheels 5,6 of the vehicle axle 4 can be driven by the drive unit 2. In the embodiment shown, the drive unit 2 is an electrically operable axle drive train with an electric machine.

2 shows an embodiment of a vehicle with a different drive concept, in which each vehicle wheel 5,6,8,9 has a drive unit 22,23,24,25 assigned to it.

In the 4 1, the control device 3 for controlling the autonomously driving vehicle 1 is shown, comprising a processor 15 and a memory 16 which contains a computer program code, the memory 16 and the computer program code being configured with the processor 15, the control device 3 for carrying out a further operation below to initiate the procedure described in more detail.

The vehicle 1, as shown in the 1-2 is shown, has at least sensors 26 for detecting the surroundings and a first control unit 20 for the autonomous driving function. Furthermore, the vehicle 1 has an air suspension system 14, via which the vehicle wheels 5, 6, 8, 9 are arranged resiliently on a chassis 19 of the vehicle 1 against the direction of gravity. A second control unit 21 is connected to the air suspension system 14. The first control device 20 and the second control device 21 are part of the control device 3 of the vehicle 1. The control device 3 of the vehicle 1 thus has - in other words - a first control device 20 for determining the trajectory 10 of the vehicle 1 and a second control device 21 Control of the air suspension system 14.

In addition to the drive unit 2 and the steering that can be actuated by the control device 3, the vehicle of course also has a brake, not shown in the figures. The actuators for the functions mentioned are not shown further. The automated driving function determines a trajectory 10 based on the sensor data from the surroundings detection. The trajectory 10 has a curve radius R. The air suspension system 14 is designed to determine the spring forces F of the respective wheel 5,6,8,9.

The inventive solution includes a method which, after loading one of the 1-2 known vehicles 1, the position of the center of gravity 27 of the vehicle 1 and adaptively the permissible lateral acceleration of the vehicle 1 is determined, as well as the trajectory planning 12 of the autonomous driving function is monitored and limited so that a predetermined lateral acceleration is not exceeded. This prevents the vehicle 1 from tipping over, even if it is unfavorably loaded.

This will be explained in more detail below using the 3 and 5 explained.

According to the method, the vehicle weight m and the position of the center of gravity 27 are determined after the vehicle 1 has been loaded. For this purpose, the goods to be transported are placed in the loading space 28. The 1 and the 2 It can also be clearly seen that the vehicle wheels 5,6,8,9 can be operatively connected to a sensor system 11 for determining the weight m of the vehicle 1, in which the weight force of the vehicle 1 acting on each of the vehicle wheels 5,6,8,9 is determined.

mit

• m= Gewicht des Fahrzeugs
• Fv1 = Kraft auf das erste Vorderrad
• Fv2 = Kraft auf das zweite Vorderrad
• Fh1 = Kraft auf das erste Hinterrad
• Fh2 = Kraft auf das zweite Hinterrad
• g = Erdbeschleunigung

The weight m of the vehicle 1 can be determined, for example, by this sensor system 11 on the vehicle wheels 5, 6, 8, 9 and/or by the air suspension system 14. The vehicle weight m is in the exemplary embodiment shown 1-2 determined by the second control unit 21 of the air suspension system 14 and results from: $$\text{m}=\left({\text{<figure-callout id="1" label="F v" filenames="DE102022112684A1\_0008.png,DE102022112684A1\_0009.png" state="{{state}}">F</figure-callout>}}_{\text{v}}+{\text{<figure-callout id="2" label="F v" filenames="DE102022112684A1\_0008.png" state="{{state}}">F</figure-callout>}}_{\text{v}}+{\text{<figure-callout id="1" label="F H" filenames="DE102022112684A1\_0008.png,DE102022112684A1\_0009.png" state="{{state}}">F</figure-callout>}}_{\text{H}}+{\text{F}}_{\text{H}2}\right)\text{/G}$$

with

• m= weight of the vehicle
• Fv1 = force on the first front wheel
• Fv2 = force on the second front wheel
• Fh1 = force on the first rear wheel
• Fh2 = force on the second rear wheel
• g = acceleration due to gravity

This step is shown in the startup diagram 5 carried out in program block a.

Determination of the position of the center of gravity 27 of the vehicle 1 in a plane 29 perpendicular to the direction of gravity and the determination of the position of the center of gravity 27 of the vehicle 1 in the direction of gravity can be based on 3 be understood. The autonomous, as a transport vehicle Vehicle 1 configured with the vehicle is in the 3 shown in a side view.

The position of the center of gravity 27 in the x direction (Ih) is first determined and the position of the center of gravity 27 in the z direction (h) is determined based on this information. This data is determined when starting or braking, based on the acceleration in the longitudinal direction/deceleration in the longitudinal direction a _x , after the vehicle 1 has been loaded. This can be done, for example, as part of a very short start-up and braking of the vehicle 1.

mit

• Ih = Position des Schwerpunkts von der Hinterachse aus
• I = Radstand
• Fv1 = Kraft auf das erste Vorderrad
• Fv2 = Kraft auf das zweite Vorderrad
• Fh1 = Kraft auf das erste Hinterrad
• Fh2 = Kraft auf das zweite Hinterrad

The position of the center of gravity 27 in the longitudinal direction (x direction) is carried out in the flowchart of the figure in the program block b and results from: $$\text{Yeh}=\text{I}*\left({\text{F}}_{\text{v}1}+{\text{F}}_{\text{v}2}\right)\text{/}\left(\left({\text{F}}_{\text{H}1}+{\text{F}}_{\text{H}2}\right)*\left({\text{F}}_{\text{v}1}+{\text{F}}_{\text{v}2}\right)\right),$$

with

• Ih = position of the center of gravity from the rear axle
• I = wheelbase
• Fv1 = force on the first front wheel
• Fv2 = force on the second front wheel
• Fh1 = force on the first rear wheel
• Fh2 = force on the second rear wheel

mit

• m= Gewicht des Fahrzeugs
• lh = Position des Schwerpunkts von der Hinterachse aus
• l = Radstand
• a_x= Soll-Beschleunigung des Fahrzeugs in Längsrichtung
• g = Erdbeschleunigung
• dF_v = Änderung der Achslast unter der Längsbeschleunigung a_x

The height h of the center of gravity 27, which is determined in program block c, results from: $$\text{H}=\left({\text{dF}}_{\text{v}}*\text{l}-\text{m}*\text{G}*\left(\text{I}-\text{lh}\right)\right)\text{/}\left(\text{m}*{\text{a}}_{\text{x}}\right),$$

with

• m= weight of the vehicle
• lh = position of the center of gravity from the rear axle
• l = wheelbase
• a _x = target acceleration of the vehicle in the longitudinal direction
• g = acceleration due to gravity
• dF _v = change in axle load under longitudinal acceleration a _x

The longitudinal acceleration a _x is caused by the drive or the brake. The second control unit determines dF _v . In a further embodiment, the deflection can also be recorded and the axle load dF _v can be determined using the known spring stiffness. For this purpose, the vehicle 1 can briefly start and brake.

mit

• S = Spurweite des Fahrzeugs
• F = Korrekturfaktor oder Korrekturfunktion
• H = Höhe h des Schwerpunktes
• g = Erdbeschleunigung

Based on the center of gravity height h, the permissible lateral acceleration q _max is determined in a program block d1 using the following relationship: $${\text{q}}_{\text{Max}}=\text{G}*\left(\text{S/}2*\text{H}\right)*\text{f},$$

with

• S = track width of the vehicle
• F = correction factor or correction function
• H = height h of the center of gravity
• g = acceleration due to gravity

The permissible lateral acceleration q _max is stored in the program block d2 in the control device 3.

The preceding steps ad are determined before the actual journey of the vehicle 1 begins. Likewise, before the start of the journey, the determination of a trajectory 10 for the vehicle 1 is carried out, the trajectory 10 comprising information which represents an acceleration a _x in the longitudinal direction of the vehicle 1 as well as a steering angle α and which _is used to determine an actual lateral acceleration q Vehicle 1 can be used.

In order to comply with the trajectory 10, the vehicle 1 must implement an acceleration in the longitudinal direction a _x and a steering angle α. This information is transferred from the trajectory planning 12 to the trajectory tracking control 13. Like in the 5 shown, the control device 3 has a module for trajectory planning 12 and a module for trajectory tracking control 13, the module for trajectory planning 12 determining the acceleration a _x in the longitudinal direction of the vehicle 1 and the steering angle α and passing it on to the module for trajectory tracking control 13.

Based on the existing vehicle speed v _is , the specified acceleration a _x and the steering angle α, the transverse acceleration q _is determined. For this purpose, the vehicle speed v _ist is determined, for example, via the wheel speed sensors 30.

wobei

• v_neu = Fahrzeuggeschwindigkeit
• v_ist = aktuelle Fahrzeuggeschwindigkeit
• a_x= Soll-Beschleunigung des Fahrzeugs in Längsrichtung
• t = Zeit

Subsequently, in the program block e2, a _new vehicle speed v _is calculated based on the current vehicle speed v, which was already determined in the program block e1, and the target acceleration a _x $${\text{v}}_{\text{new}}={\text{v}}_{\text{is}}+{\text{a}}_{\text{x}}*\text{t}$$

where

• v _new = vehicle speed
• v _is = current vehicle speed
• a _x = target acceleration of the vehicle in the longitudinal direction
• t = time

mit

• R = Kurvenradius
• l = Radstand
• α = Lenkwinkel

The curve radius R is then determined in the program block e3 based on the steering angle specification α and the wheelbase I of the vehicle 1 $$\text{R}=\text{I/}\mathrm{\alpha },$$

with

• R = curve radius
• l = wheelbase
• α = steering angle

• q_ist = Ist-Querbeschleunigung
• v_neu = Fahrzeuggeschwindigkeit
• R = Kurvenradius

This allows the actual lateral acceleration q to be determined in the program block f _on the basis of v _new and the curve radius R, with $${\text{Q}}_{\text{is}}={\left({\text{v}}_{\text{new}}\right)}^2*\text{R},$$

• q _is = actual lateral acceleration
• v _new = vehicle speed
• R = curve radius

Now, in the program block g, a comparison of the actual lateral acceleration q _is of the vehicle 1 with the permissible lateral acceleration q _max and in the presence of the condition that the actual lateral acceleration q _is of the vehicle 1 is greater than the permissible lateral acceleration q _max , In the program block h, a corrected acceleration a _{korr is} calculated to reduce the actual vehicle speed v ist. If the resulting lateral acceleration q _exceeds the maximum permissible lateral acceleration q _max depending on the current state of charge, a corrected acceleration a _korr is calculated. However, if the ACTUAL lateral acceleration q _falls below the maximum lateral acceleration q _max , the acceleration a _x is implemented by the drive system.

The method described can in particular be embodied as a computer program product stored on a machine-readable medium, or computer data signal, embodied by an electromagnetic wave, with program code suitable for carrying out the method described above.

The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be viewed as limiting but rather as illustrative. The following patent claims are to be understood as meaning that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of other features. If the patent claims and the above description define 'first' and 'second' features, this designation serves to distinguish two similar features without establishing a ranking.

Reference symbol list

1

vehicle

2

Drive unit

3

Control device

4

Vehicle axle

5

vehicle wheel

6

vehicle wheel

7

Vehicle axle

8th

vehicle wheel

9

vehicle wheel

10

Trajectory

11

Sensors

12

Trajectory planning

13

Trajectory tracking control

14

Air suspension system

15

processor

16

Storage

19

chassis

20

Control unit

21

Control unit

22

Drive unit

23

Drive unit

24

Drive unit

25

Drive unit

26

Sensors

27

main emphasis

28

cargo space

29

level

30

Wheel speed sensor

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102017106826 A1 [0005]
• DE 102011080761 A1 [0007]
• DE 102017212899 A1 [0007]
• DE 1752295 U [0008]
• DE 102019119074 A1 [0008]
• US 20180129958 A [0008]

Claims (10)

Method for controlling an autonomously driving vehicle (1) with a drive unit (2) and a control device (3) for controlling the vehicle (1), with a first vehicle axle (4) with at least two vehicle wheels (5,6), which have a first Define track width S ₁ , and a second vehicle axle (7) running parallel to the first vehicle axis (4) with at least two vehicle wheels (8,9) which define a second track width S ₂ , at least the vehicle wheels (5,6,8,9 ) can be steered on one of the vehicle axles (4,7) by the control device (3), and two vehicle wheels (5,6,8,9) of one of the vehicle axles (4,7) can be driven by the drive unit (2), comprising the the following steps a) determining the weight m of the vehicle (1); b) determining the position of the center of gravity (27) of the vehicle (1) in a plane (29) perpendicular to the direction of gravity; c) determining the position of the center of gravity (27) of the vehicle (1) in the direction of gravity; d) determining a permissible lateral acceleration q _max for the vehicle (1) and storing the permissible lateral acceleration q _max in the control device (3); e) determining information from a trajectory (10), which _represents an actual vehicle speed v, an acceleration a _x in the longitudinal direction of the vehicle (1) and a steering angle α and which _{is used} to f) determine an actual lateral acceleration q of the vehicle (1) be used; g) Comparison of the actual lateral acceleration q _is of the vehicle (1) with the permissible lateral acceleration q _max and in the presence of the condition that the actual lateral acceleration q _is of the vehicle (1) is greater than the permissible lateral acceleration q _max ; h) Determination of a corrected acceleration a _korr to reduce the actual vehicle speed v _ist . Procedure according to Claim 1 , characterized in that steps a)-d) are determined before the vehicle (1) begins to travel. Procedure according to Claim 1 or 2 , characterized in that the vehicle wheels (5,6,8,9) are operatively connected to a sensor system (11) for determining the weight m of the vehicle (1), in which the on each of the vehicle wheels (5,6,8,9 ) acting weight of the vehicle (1) is determined. Method according to one of the preceding claims, characterized in that the control device (3) comprises a module for trajectory planning (12) and a module for trajectory tracking control (13), the module for trajectory planning (12) controlling the acceleration a _x in the longitudinal direction of the vehicle ( 1) and the steering angle α is determined and passed on to the trajectory tracking control module (13). Computer program product stored on a machine-readable medium, or computer data signal embodied by an electromagnetic wave, with program code suitable for carrying out the method according to Claim 1 - 4 . Control device (3) for controlling an autonomously driving vehicle (1), comprising a processor (15) and a memory (16) which contains a computer program code, the memory (16) and the computer program code being configured with the processor (15) , the control device (3) for carrying out a method Claim 1 - 4 to cause. Autonomously driving vehicle (1) with a drive unit (2) and a control device (3) for controlling the vehicle (1), with a first vehicle axle (4) with at least two vehicle wheels (5,6) which define a first track width S ₁ , and a second vehicle axle (7) running parallel to the first vehicle axle (4) with at least two vehicle wheels (8,9) which define a second track width S ₂ , with at least the vehicle wheels (5,6,8,9) on one of the Vehicle axles (4,7) can be steered by the control device (3), and two vehicle wheels (5,6,8,9) of one of the vehicle axles (4,7) can be driven by the drive unit (2), characterized in that the control device (3) after Claim 6 is executed. Vehicle (1) after Claim 7 , characterized in that the vehicle (1) has an air suspension system (14), via which the vehicle wheels (5,6,8,9) are arranged resiliently on a chassis (19) of the vehicle (1) against the direction of gravity. Vehicle (1) after Claim 7 or 8th , characterized in that the control device (3) of the vehicle (1) has a first control device (20) for determining the trajectory (10) of the vehicle (1) and a second control device (21) for controlling the air suspension system (14). Vehicle (1) according to one of the previous ones Claims 7 - 9 , characterized in that each vehicle wheel (5,6,8,9) has a drive unit (22,23,24,25) assigned to it.

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