Method for controlling a vehicle on a closed site, control unit and vehicle

Description

[0001] The invention relates to a method for controlling a vehicle, in particular a commercial vehicle, on a closed site, in particular a depot, a control unit for carrying out the method and a vehicle.

[0002] Vehicles, especially commercial vehicles, that do not have an active automated steering system can only be integrated into an autonomously managed depot or freight forwarding yard as a closed area to a limited extent, as they cannot follow a predefined path from a starting area to a destination area fully automatically. This is only possible if a driver or operating personnel assumes the driving function, especially the steering function, which means that more personnel than necessary or desired are involved in the depot. However, this is undesirable for autonomously operating vehicles or depots. Retrofitting an active automated steering system is also expensive.

[0003] It is known from the prior art to implement a steering function by controlling service brakes on individual wheels (steering brakes). For example, DE 10 2012 104 793 A1, DE 196 32 251 A1, EP 2 998 175 A1, and DE 10 2006 046 497 A1 describe how to ensure the steering of a vehicle by using the steering brake as a redundant fallback level. Further steering brake functions are described in DE 10 2017 102 021 A1 and DE 10 2019 108 620 A1.

[0004] EP 3 293 064 A1 and EP 3 293 065 A1 also provide for switching back and forth between steering via an automated steering system and steering via steering braking via a switching module, whereby the respective steering is intended to carry out automatic corrections when carrying out autonomous driving maneuvers as part of a lane keeping or lane change assistance system.

[0005] DE102016116857A1 discloses a system for operating a driverless commercial vehicle in a restricted area, wherein the restricted area has an entrance, an exit, and a predetermined destination. The system comprises a transfer module for transferring control of the commercial vehicle at the entrance from the driver of the commercial vehicle to the system, and at the exit and further from the system to the driver of the commercial vehicle. The system further comprises a movement module for autonomously moving the commercial vehicle from the entrance to the predetermined destination and from the predetermined destination to the exit, and an execution module for autonomously performing an action on the commercial vehicle while the commercial vehicle is at the predetermined destination, in order to change a state of the commercial vehicle through the action.

[0006] The object of the invention is to provide a method for controlling a vehicle on a closed site, which allows any vehicle to access an automated site without great effort. The object of the invention is also to provide a control unit and a vehicle.

[0007] This object is achieved by a method, a control unit, and a vehicle according to the independent claims. The subclaims specify preferred developments.

[0008] According to the invention, a method is therefore provided for controlling a vehicle on a closed site, in particular on a depot, wherein the vehicle has a control unit which is designed to automatically control a braking system and a drive system in the vehicle in order to move the vehicle automatically, ie driverless or autonomously, along a defined path.

[0009] After determining that the vehicle does not have a steering system that can be controlled via automatically generated steering control signals to automatically influence the steering angle of the wheels of a steered vehicle axle, at least the following steps must be performed. "Availability" includes both the presence and functionality of such an automatically controllable steering system, which is thus initially determined. This determination preferably occurs in the starting area of ​​the closed area, for example, upon arrival at the closed site.

[0010] The steps taken are in particular: Determining a path between a starting area and a specified target area on the closed site, wherein, when determining the path, it is taken into account, for example, that the steering angle at the wheels of the steered vehicle axle can only be influenced by automated control of brakes of the braking system in the vehicle; generating drive control signals and steering brake control signals in such a way that, with subsequent automated control of the drive system and the braking system with these control signals, the vehicle moves from the starting area along the path to the specified target area and the steering angle changes only due to automated control of the brakes of the braking system.

[0011] According to the invention, a control unit for carrying out the method and a vehicle with the control unit are also provided.

[0012] Advantageously, a steering brake function is thus implemented, allowing the vehicle, which in this case does not have the option of automatically adjusting the steering angle via a conventional steering system, to be steered automatically on the enclosed terrain. This steering is enabled via the steering brake control signal in that, when the braking system is automatically activated, the brakes are controlled individually for each wheel using this steering brake control signal. This creates a differential brake pressure between the wheels of the same vehicle axle. This differential brake pressure results in a steering torque when the respective steered wheels have a positive steering roll radius. This results in a steering angle at the wheels of the steered vehicle axle that is related to the differential brake pressure.In this way, a vehicle with a defective or non-existent automated steering system can still be integrated into an automated closed area, in particular a depot or a forwarding agency yard, without the need for manual control, which is undesirable in such automated yards for reasons of mutual and safe coordination.

[0013] Preferably, it can further be provided that the path is defined in such a way that the steering angle at the wheels of the steered vehicle axle remains below a defined limit steering angle, for example, below 20°, during automated control of the braking system with the steering brake control signals to move the vehicle along the path. This prevents wear on the vehicle's brakes, since for larger steering angles, a correspondingly greater differential brake pressure would be necessary to generate a greater steering torque, which would also mean greater absolute brake pressures. This can be taken into account when planning or defining the path, for example by specifying fewer curve sections and / or correspondingly smaller bends that are traversed with the maximum limit steering angle in the existing curve sections between the starting area and the destination area.

[0014] Preferably, the path is further defined by a management system of the enclosed area or by a control unit in the vehicle. Thus, the management system can access the infrastructure of the area to achieve more reliable path planning, or path planning can be performed autonomously from the vehicle, for example, if a management system is currently unavailable or not present.

[0015] Preferably, it can further be provided that vehicle information relating to the vehicle is transmitted to the management system of the closed area in order to determine the path, so that the management system can determine in advance whether or not an automatically controllable steering system is available in the vehicle. For this purpose, a wireless network of the closed area can be used, for example. If an automatically controllable steering system is available, the path can then be planned as usual without the additional restrictions resulting from steering braking. If no automatically controllable steering system is available, which can be deduced from the vehicle information from the management system, path planning then takes place as described above. The management system can therefore automatically initiate the appropriate path planning routine depending on the determined vehicle equipment.

[0016] Preferably, it is further provided that the path and / or the target area is / are determined depending on obstacles and / or other vehicles on the enclosed terrain. It can be taken into account that, due to limitations such as the adjustable steering angle due to the steering brake function, certain maneuvers are more complex or even impossible. It should also be considered that the vehicle must be moving for a steering movement. The path and the target area can be determined or selected accordingly.

[0017] It is preferably further provided that, before the drive system and the braking system are automatically controlled with the control signals, a check is carried out to determine whether the vehicle mass of the vehicle falls below or exceeds a specified limit mass, for example 31 t. This can prevent excessive wear, which can occur with particularly heavy vehicles. It is preferably provided that release for the automated generation of the steering brake control signal and / or for the automated control of the vehicle's braking system with the steering brake control signal, i.e. steering braking, only occurs when the vehicle mass falls below the limit mass. Steering braking is therefore suppressed and the vehicle must move to the target area, if necessary manually controlled, until, for example, after unloading, the vehicle mass is again below the limit mass.

[0018] Preferably, it is further provided that, at least during the automated actuation of the braking system with the steering brake control signal, a brake temperature of at least the brakes that are automatically actuated is monitored, wherein automated generation of the steering brake control signal and / or automated actuation of the vehicle's braking system with the steering brake control signal, i.e., steering braking, is only maintained when the brake temperature is below a temperature limit. This allows for additional wear monitoring, which can be derived from an increased brake temperature.

[0019] Preferably, it is further provided that a steering brake period is determined which indicates how long an automated control of the braking system with the steering brake control signal for the automated travel of the path via the steering brake has taken place, wherein an automated generation of the steering brake control signal and / or an automated control of the braking system of the vehicle with the steering brake control signal, i.e. a steering brake, is only maintained until the steering brake period exceeds a specified limit period. This also makes it possible to estimate wear, since an increased duration for steering braking is an indication of excessive wear. This can also be combined with the temperature monitoring described above. In principle, however, wear can also be estimated based on the steering brake period alone.

[0020] Preferably, the target area also includes a loading ramp, unloading area, or parking space. This allows for flexible use of the method, which can be applied not only at a depot or freight forwarding yard, but also at a rest area or port area.

[0021] The invention is explained in more detail below with reference to the figures. They show: Fig. 1 shows a schematic view of a depot as a closed area; Fig. 1a shows a schematic view of a vehicle; and Fig. 2 shows a flowchart of the method according to the invention.

[0022] Figur 1a shows schematically a vehicle 1, which consists of a towing vehicle 1a and a trailer 1b coupled to it and which is arranged according to Fig. 1 is located on an enclosed site 2, for example a depot 2a (freight forwarding yard) or a rest area or a port area. The enclosed site 2a is controlled or coordinated by a management system 3, which ensures in particular that arriving vehicles 1 are guided from a starting area 4 along a specified path P to a defined destination area 5, for example to a specified loading ramp 5a.

[0023] For this purpose, the path P is planned or determined by the management system 3 depending on certain vehicle information I1, which may contain, for example, a load, an authorization, a destination, vehicle equipment, etc., and transmitted via any communication system 6, for example a stationary and local wireless network 6a (e.g. WLAN), to a vehicle control unit 10 in the relevant vehicle 1. The vehicle control unit 10 then ensures that the vehicle 1 moves automatically along the specified path P to the target area 5 by controlling the corresponding system components of the vehicle 1 via control signals.

[0024] The path P is determined in particular depending on the vehicle equipment, from which it can be derived which system components the vehicle control unit 10 can control in order to follow the defined path P. This makes it possible to take into account the manner in which autonomous control of the vehicle 1 is possible on the enclosed site 2. If, for example, no automatically controllable steering system 20 is available in the vehicle 1, via which a steering angle d of the wheels 7 of a steerable vehicle axle 8, in particular the front axle of the vehicle 1, can be actively adjusted, this must be taken into account accordingly when planning the path P by the management system 3, so that such a vehicle 1 can also be integrated into the automated process at the depot 2a.

[0025] Within the framework of a method for controlling the vehicle 1 on the enclosed site 2, in particular the depot 2a, according to the flow chart in Fig. 2Under this condition, for example, the following procedure is provided: First, in an initial step ST0, management system 3 determines from vehicle information I1 whether an automatically controllable steering system 20 is available, i.e., whether it is present in vehicle 1 and is therefore functional. If this is the case, path P can be planned by management system 3 as usual such that vehicle 1 is moved along path P by automated control of the automatically controllable steering system 20 via steering control signals SL, of the automatically controllable drive system 30 via drive control signals SA, and of the automatically controllable braking system 40 via braking control signals SB. The respective control signals SA, SB, SL are also generated automatically by control unit 10 depending on path P. When determining path P, the infrastructure at depot 2a is used, i.e.obstacles H and other stationary or moving vehicles 100 are detected and taken into account.

[0026] In the event that an automatically controllable steering system 20 is not available in the vehicle 1 because such a system is not present or is defective, when determining the path P from the start area 4 to the destination area 5, the management system 3 takes into account in a first step ST1 that steering of the vehicle 1 by setting a specific steering angle d on the wheels 7 of the steered vehicle axle 8 can only take place within the framework of a steering brake function.

[0027] In principle, the initial check step ST0 and the first step ST1 for determining the path P can also be carried out by the control unit 10 itself, whereby instead of relying on the infrastructure of the depot 2a, a sensor system 50 with the sensors in the vehicle 1 is used to plan and determine the path P. The vehicle information I1, in particular the vehicle equipment, is known to the control unit 10 itself, so that the planning and determination of the path P can also take place from this perspective.

[0028] The control unit 10 will then, in a subsequent second step ST2, generate steering brake control signals SBL instead of the steering control signals SL for the automated steering of the vehicle 1 in order to influence the steering angle d of the wheels 7 of the steered vehicle axle 8, wherein at the same time a drive control signal SA is also generated, since steering braking is only possible while the vehicle 1 is traveling (forwards or backwards). These generated steering brake control signals SBL and drive control signals SA are then automatically transmitted to the braking system 40 and the braking system 40, respectively, in a third step ST3.the drive system 30, whereupon, when the vehicle 1 is moving, a specific steering torque L results on the vehicle 1 through a wheel-individual control of the brakes 9, in particular on the wheels 7 of the steered vehicle axle 8, which, due to the positive steering roll radius on the wheels 7 of the steered vehicle axle 8, ensures that these wheels 7 are turned by a specific steering angle d and thus that the driven vehicle 1 is steered.

[0029] The steering brake control signals SBL are generated in such a way that a differential brake pressure dP is built up at the wheels 7 of the steered vehicle axle 8 by individually controlling the brakes 9 for each wheel, whereby the brake pressure at one of the brakes 9 of the steered vehicle axle 8 is ideally zero in order not to place unnecessary strain on the brakes 9. This differential brake pressure dP corresponds, via the built-up steering torque L (and via the positive steering roll radius), to a resulting steering angle d at the wheels 7 of the steered vehicle axle 8, which in turn automatically implements the steering command at the respective position of the path P. In this way, the specified path P can be followed by automated control of the braking system 40 with the steering brake control signal SBL and of the drive system 30 with the drive signals SA.Braking or driving of the vehicle 1 is achieved by superimposing the drive control signal SA or the brake control signal SB with the steering brake control signal SBL.

[0030] Since vehicle 1 can be steered less effectively by steering braking or only with a limit steering angle dG of, for example, 20°, this must be taken into account when defining path P by management system 3 in the first step ST1. Although larger steering angles d than a limit steering angle dG of 20° can also be achieved by the described steering braking, this only results in increased wear on the respective brakes 9 controlled. It must therefore also be taken into account that increased wear on the respective brakes 9 controlled for steering braking occurs due to steering braking. Accordingly, path P must be defined, for example, such that it has only a few curve sections KA and / or only curve sections KA with a slight curvature K occur, so that the set differential brake pressure dP and accordingly also the absolute brake pressures at the respective brakes 9 are lower.

[0031] Under certain circumstances, the definition of the target area 5, where, for example, a load is to be picked up or dropped off, may also need to be taken into account. For example, it may be taken into account that a vehicle 1 without an automatically controllable steering system 30 can only maneuver to a free loading ramp 5a between two loading ramps 5a already occupied by other vehicles 100 with great effort and with a large number of curve sections KA, relying on steering braking as described above. Therefore, in this situation, path P with a correspondingly different loading ramp 5a should be selected as the target area 5, where fewer curve sections KA and / or curve sections KA with a smaller curvature K are necessary.

[0032] Before or after determining the path P for the automated control of vehicle 1 using the steering brake function (first step ST1), a vehicle mass M of vehicle 1 can additionally be detected, e.g., from pressure information from an air suspension and / or another mass estimate, in order to enable the subsequent automated control of vehicle 1 depending thereon. In an intermediate step STZ, it is checked whether the detected vehicle mass M exceeds a limit mass MG of, for example, 31 t. Only if the limit mass MG is undershot does the automated generation of the steering brake control signal SBL and / or the automated control of the braking system 30 with the steering brake control signal SBL subsequently occur in steps ST2 or ST3.Similarly, a release of the steering brake function can be permanently activated, whereby the steering brake function is suppressed by the control unit 10 if the limit mass MG is exceeded.

[0033] This takes into account that implementing the steering brake function on very heavy vehicles 1 can lead to very high wear on the brakes 9. For a vehicle 1 with a vehicle mass M that is greater than the limit mass MG, the vehicle 1 must therefore be driven independently or manually to the target area 5 in the depot 2a. This would then be, for example, a route on which the vehicle 1 is fully loaded (on the way to unloading at the target area 5 or on the way back after loading in the target area 5), ​​whereas the route before loading or after unloading could be covered automatically, provided the vehicle mass M is below the limit mass MG.

[0034] When traveling along path P using the steering brake function, additional temperature monitoring may be provided. For this purpose, a temperature sensor 51 is arranged on the brakes 9. If a brake temperature T9 of individual brakes 9 exceeds a temperature limit value TG, the enable for the automated generation of the steering brake control signal SBL and / or for the automated control of the braking system 30 with the steering brake control signal SBL is revoked in steps ST2 or ST3, or the steering brake function is suppressed.

[0035] Additionally or alternatively, a steering brake period tBL can also be measured, within which the brakes 9 are activated to implement the steering brake function, for example, by an automated function in the braking system 30 and / or by the control unit 10. If a limit period tG is exceeded, regardless of the level of the brake temperature T9, it is provided that an enable for the automated generation of the steering brake control signal SBL and / or for the automated control of the automated braking system 30 with the steering brake control signal SBL is withdrawn in steps ST2 or ST3, or the steering brake function is suppressed. This prevents excessive wear, regardless of the brake temperature T9.

[0036] Instead of specifying the path P for shunting to a loading ramp 5a, it is also possible to provide for unloading of bulk goods at an unloading point 15, in which case the path P must then also be selected accordingly under the conditions described above with regard to steering braking.

[0037] By appropriately controlling the respective system components 20, 30, 40 by the control unit 10, the path P can be traveled automatically, wherein the control unit 10 can also monitor this automated journey accordingly by using a sensor system 50 with the corresponding sensors in the vehicle 1, for example by carrying out an actual / target comparison of the position of the vehicle 1 and / or obstacle detection.

[0038] If the vehicle 1 has subsequently arrived in the target area 5 in the correspondingly provided pose (orientation, position) in a fourth step ST4, the respective task can be carried out, e.g. loading, unloading, service activities, etc., before the vehicle 1 subsequently moves again on a predetermined path P to another target area or back to the original starting area 4 to leave the depot 2a.

[0039] Instead of at a depot 2a as described, the method can also be carried out at a rest area as a closed area 2, whereby the driver drops off the vehicle 1 at the rest area entrance (starting area 4) and the vehicle 1 is then maneuvered autonomously under steering braking into a free parking space 16 (target area 5) which can be reached with the steering braking function. List of reference symbols (part of the description)

[0040] 1Vehicle 1aTowing vehicle 1bTrailer 2Enclosed area 2aDepot 3Management system 4Start area 5Destination area 5aLoading ramp 6Communication system 6aWireless network 7Wheel 8Steerable vehicle axle 9Brake 10Vehicle control unit 15Unloading area 16Parking space 20Automatically controllable steering system 30Automatically controllable drive system 40Automatically controllable braking system 50Sensor system 51Temperature sensors 100Other vehicles dSteering angle dGLimit steering angle dPDifferential brake pressure HHobstacle MVehicle mass MGGLimit mass I1Vehicle information PPPath KKurve KACorner section LLeering torque SADrive control signal SBBraking control signal SBLSteering brake control signal tBLSterding brake period tGGLimit period T9Brake temperature TGGLimit temperature ST0, ST1, ST2, ST3, ST5, STZSteps of the procedure

Claims

1. Method for controlling a vehicle (1) on a closed site (2), in particular at a depot (2a), wherein the vehicle (1) has a control unit (10) which is designed to automatically control a braking system (30) and a drive system (40) in the vehicle (1) in order to move the vehicle (1) automatically along a defined path (P), wherein, after determining that no steering system (20) is available in the vehicle (1) that can be controlled via automatically generated steering control signals (SL) in order to automatically influence (ST0) a steering angle (d) of wheels (7) of a steered vehicle axle (8) of the vehicle (1), at least the following steps are carried out: - defining a path (P) between a starting region (4) and a defined destination region (5) on the closed site (2) (ST1); - generating drive control signals (SA) and steering brake control signals (SBL) such that the vehicle (1) moves from the starting region (4) along the path (P) into the defined destination region (5) with a subsequent automated control of the drive system (40) and the braking system (30) using these control signals (SA, SBL), and the steering angle (d) changes only due to automated control of the brakes (9) of the braking system (30) (ST3).

2. Method according to claim 1, characterized in that the path (P) is defined in such a way that the steering angle (d) at the wheels (7) of the steered vehicle axle (8) remains below a defined limit steering angle (dG) when the braking system (30) is automatically controlled with the steering brake control signals (SBL) to move the vehicle (1) along the path (P).

3. Method according to claim 2, characterized in that the limit steering angle (dG) is 20°.

4. Method according to any of the preceding claims, characterized in that the path (P) is defined by a management system (3) of the closed site (2) or on a control unit (10) in the vehicle (1).

5. Method according to claim 4, characterized in that vehicle information (11) relating to the vehicle (1) is transmitted to the management system (3) of the closed site (2) for defining the path (P), so that the management system (3) can determine in advance whether an automatically controllable steering system (20) is available in the vehicle (1).

6. Method according to any of the preceding claims, characterized in that when the path (P) is defined, it is taken into account that the steering angle (d) at the wheels (7) of the steered vehicle axle (8) can be influenced only by automated control of brakes (9) of the braking system (30) in the vehicle (1).

7. Method according to any of the preceding claims, characterized in that the path (P) and / or the destination region (5) is or are defined depending on obstacles (H) and / or other vehicles (100) on the closed site (2).

8. Method according to any of the preceding claims, characterized in that before the drive system (40) and the braking system (30) are automatically controlled with the control signals (SA, SBL) (ST3), it is checked whether a vehicle mass (M) of the vehicle (1) falls below or exceeds a defined limit mass (MG), for example 31t.

9. Method according to claim 8, characterized in that a release for the automated generation of the steering brake control signal (SBL) and / or for the automated control of the braking system (30) of the vehicle (1) with the steering brake control signal (SBL) only occurs (STZ) when the vehicle mass (M) falls below the limit mass (MG).

10. Method according to any of the preceding claims, characterized in that at least during the automated control of the braking system (30) with the steering brake control signal (SBL), a brake temperature (T9) of at least the brakes (9) which are automatically controlled is monitored, an automated generation of the steering brake control signal (SBL) and / or an automated control of the braking system (30) of the vehicle (1) with the steering brake control signal (SBL) being maintained only when the brake temperature (T9) is below a temperature limit value (TG).

11. Method according to any of the preceding claims, characterized in that a steering brake period (tBL) is determined which indicates how long an automated control of the braking system (30) with the steering brake control signal (SBL) for the automated travel of the path (P) has taken place, an automated generation of the steering brake control signal (SBL) and / or an automated control of the braking system (30) of the vehicle (1) with the steering brake control signal (SBL) being maintained only until the steering brake period (tBL) exceeds a defined limit period (tG).

12. Method according to any of the preceding claims, characterized in that the steering brake control signal (SBL) is generated in such a way that the brakes (9) are controlled individually for each wheel with this steering brake control signal (SBL) when the braking system (30) is controlled automatically, so that a differential brake pressure (dP) is formed between wheels (7) of the same vehicle axle (8), as a result of which a steering torque (L) results and a steering angle (d) related to the differential brake pressure (dP) is established at the wheels (7) of the steered vehicle axle (8).

13. Method according to any of the preceding claims, characterized in that there is a loading ramp (5a) or an unloading place (15) or a parking space (16) in the destination region (5).

14. Method according to any of the preceding claims, characterized in that determining whether an automatically controllable steering system (20) is available in the vehicle (1) takes place in the starting region (4) of the closed site (2).

15. Control unit (10) for a vehicle (1), in particular for carrying out a method according to any of the preceding claims, wherein the control unit (10) is designed to automatically control a braking system (30) and a drive system (40) in the vehicle (1) in order to automatically move the vehicle (1) along a defined path (P), wherein the control unit (10) is designed to generate drive control signals (SA) and steering brake control signals (SBL) such that the vehicle (1) moves from the starting region (4) along a predefined path (P) into the defined destination region (5) with an automated control of the drive system (40) and the braking system (30) using these control signals (SA, SBL), and the steering angle (d) changes only due to automated control of the brakes (9) of the braking system (30), wherein, when the path (P) is defined between a starting region (4) and a defined destination region (5) on the closed site (2), it is taken into account that the steering angle (d) at the wheels (7) of the steered vehicle axle (8) can be influenced only by automated control of brakes (9) of the braking system (30) in the vehicle (1).

16. Control unit (10) according to claim 15, characterized in that the control unit (10) is designed to determine the path (P) itself or to receive the path (P) from a management system (3) of the closed site (2).

17. Vehicle (1) comprising a braking system (30) and a drive system (40) and a control unit (10) according to claim 15 or 16.