Patent ID: 12208833

DETAILED DESCRIPTION

In an embodiment, the invention provides a method for controlling a vehicle within a confined site, by means of which method any vehicle can, without great expenditure, be afforded access to a site that is operated in automated fashion. In an embodiment, a control unit and a vehicle are provided.

Accordingly, an embodiment of the invention provides a method for controlling a vehicle within a confined site, in particular within a depot, wherein the vehicle has a control unit that is designed to control a brake system and a drive system in the vehicle in automated fashion in order to move the vehicle in automated fashion, that is to say in driverless or autonomous fashion, along a specified path.

Following a determination that there is no steering system available in the vehicle that can be controlled by way of steering control signals generated in automated fashion in order to influence a steering angle of wheels of a steered vehicle axle of the vehicle in automated fashion, at least the following steps are carried out. Here, the “availability” relates both to the presence and to the functionality of such a steering system that is controllable in automated fashion, and this is therefore firstly determined. The determination is preferably performed in the starting area of the confined area, for example following arrival at the confined site.

The steps that are carried out are in particular as follows:specifying a path between a starting area and a specified destination area within the confined site, wherein, in the specification of the path, it is for example taken into consideration that the steering angle at the wheels of the steered vehicle axle can only be influenced by automated control of brakes of the brake system in the vehicle;generating drive control signals and steering braking control signals such that, during subsequent automated control of the drive system and of the brake system using said control signals, the vehicle moves from the starting area along the path to the specified destination area, and the steering angle varies owing solely to automated control of the brakes of the brake system.

According to an embodiment of the invention, a control unit for carrying out the method, and a vehicle having the control unit, are also provided.

A steering braking function is advantageously thus implemented, with which the vehicle, which in this case has no facility for automated setting of a steering angle by means of a conventional steering system, can nevertheless be steered in automated fashion within the confined site. This steering by means of the steering braking control signal is made possible by virtue of the brakes being controlled on a wheel-specific basis during automated control of the brake system using said steering braking control signal, such that a differential brake pressure is generated between wheels of the same vehicle axle, which results in a steering moment in the case of a positive scrub radius (kingpin offset) of the steered wheels in question, causing a steering angle associated with the differential brake pressure to be set at the wheels of the steered vehicle axle. In this way, a vehicle having a defective automated steering system or having no automated steering system can nevertheless be incorporated into a confined site that is operated in automated fashion, in particular a depot or a haulage depot, without the need for manual control which, for the purposes of mutual and safe coordination, is undesired within such depots that are operated in automated fashion.

Provision can furthermore be made whereby the path is specified such that, during automated control of the brake system using the steering braking control signals for the purposes of moving the vehicle along the path, the steering angle at the wheels of the steered vehicle axle remains below a specified limit steering angle, for example below 20°. Wear of the brakes of the vehicle is thus avoided, because, for greater steering angles, a correspondingly higher differential brake pressure would be required to generate a higher steering moment, which would also entail higher absolute brake pressures. This can already be taken into consideration in the planning or specification of the path, for example through the specification of fewer curve sections, and/or curvatures of correspondingly lesser degree, travel through which involves the limit steering angle at a maximum, in the curve sections provided, between the starting area and the destination area.

Provision is preferably furthermore made whereby the path is specified by a management system of the confined site or on a control unit in the vehicle. The management system can thus draw upon the infrastructure of the site in order to achieve more reliable path planning, or else path planning can be performed autonomously by the vehicle, for example if a management system is not currently available or is not provided.

Provision can preferably furthermore be made whereby vehicle information items relating to the vehicle are transmitted to the management system of the confined site for the purposes of specifying the path, such that the management system can identify in advance whether or not a steering system that is controllable in automated fashion is available in the vehicle. For example, a wireless network of the confined site can be used for this purpose. If a steering system that is controllable in automated fashion is available, the planning of the path is then possible in the conventional manner, without the additional limitations that arise from steering braking. If no steering system that is controllable in automated fashion is available, which can be derived by the management system from the vehicle information items, the path planning is then performed as described above. The management system can thus automatically initiate the relevant path planning routine in accordance with the determined vehicle equipment specification.

Provision is preferably furthermore made whereby the path and/or the destination area are/is specified in a manner dependent on obstructions and/or other vehicles within the confined site. It can be taken into consideration here that, owing to the limitations imposed by the steering braking function on the settable steering angle, for example, certain shunting maneuvers are more complicated or impossible, wherein it can also be considered that the vehicle can be in motion for a steering movement. The path, and the destination area, can be specified or selected accordingly.

Provision is preferably furthermore made whereby, prior to the automated control of the drive system and of the brake system using the control signals, it is checked whether a vehicle mass of the vehicle is lower or higher than a specified limit mass, for example 31t (tonnes). Excessive wear that may occur in the case of particularly heavy vehicles can thus be avoided. Provision is preferably made whereby automated generation of the steering braking control signal and/or automated control of the brake system of the vehicle using the steering braking control signal, that is to say steering braking, is allowed only if the vehicle mass is lower than the limit mass. Steering braking is thus suppressed, and the vehicle can be steered manually to the destination area as necessary, for example until the vehicle mass is below the limit mass again after the unloading operation.

Provision is preferably furthermore made whereby, at least during the automated control of the brake system using the steering braking control signal, a brake temperature at least of those brakes which are controlled in automated fashion is monitored, wherein automated generation of the steering braking control signal and/or automated control of the brake system of the vehicle using the steering braking control signal, that is to say steering braking, is maintained only if the brake temperature is below a temperature limit value. Additional monitoring of wear, which can be derived from an elevated brake temperature, is thus possible.

Provision can preferably furthermore made whereby a steering braking duration is ascertained which indicates the length of time for which automated control of the brake system using the steering braking signal has been performed for the purposes of traveling along the path in automated fashion by way of steering braking, wherein automated generation of the steering braking control signal and/or automated control of the brake system of the vehicle using the steering braking control signal, that is to say steering braking, is maintained only until such time as the steering braking duration exceeds a specified limit duration. Wear can be estimated in this way, too, because an increased duration for steering braking is a sign of excessive wear. This can also be combined with the temperature monitoring described above. In principle, the wear can also be estimated solely on the basis of the steering braking duration.

Provision is preferably furthermore made whereby a loading ramp or an unloading location or a parking space is situated in the destination area. Flexible use of the method is thus realized, which method can be implemented not only within a depot or a haulage depot but also within a rest area or a port site.

FIG.1aschematically shows a vehicle1which includes a tractor vehicle1aand a trailer1bcoupled thereto, and which, as perFIG.1, is situated within a confined site2, for example a depot2a(haulage depot) or a rest area or a port site. The confined site2ais controlled and coordinated by a management system3, which in particular ensures that arriving vehicles1are directed from a starting area4along a specified path P to a defined destination area5, for example to a specified loading ramp5a.

For this purpose, the path P is planned or specified by the management system3in a manner dependent on certain vehicle information items I1, which many for example include a payload, an authorization, a destination, a vehicle equipment specification etc., and is transmitted via an arbitrary communication system6, for example a static and local wireless network6a(for example WLAN), to a vehicle control unit10in the relevant vehicle1. Then, by controlling the relevant system components of the vehicle1using control signals, the vehicle control unit10ensures that the vehicle1moves in automated fashion along the specified path P to the destination area5.

Here, the path P is specified in particular in accordance with the vehicle equipment specification, from which it can be derived what system components the vehicle control unit10can control in order to follow the specified path P. The manner in which the vehicle1can be autonomously controlled on the confined site2can thus be taken into consideration. For example, if no steering system20which is controllable in automated fashion, and by means of which a steering angle d of the wheels7of a steerable vehicle axle8, in particular the front axle of the vehicle1, can be actively set, is available in the vehicle1, this can be correspondingly taken into consideration in the planning of the path P by the management system3such that even a vehicle1of the type in question can be incorporated into the automated course of events within the depot2a.

Under these conditions, in the context of a method for controlling the vehicle1within the confined site2, in particular the depot2a, it is for example the case that the following approach is provided, as per the flow diagram inFIG.2:

Firstly, in an initial step ST0, the management system3ascertains, on the basis of the vehicle information items I1, whether a steering system20that is controllable in automated fashion is available, that is to say is present in the vehicle1and is correspondingly also functional. If this is the case, the path P can be planned by the management system3in the conventional manner such that the vehicle1is moved along the path P by automated control of the steering system20, which is controllable in automated fashion, using steering control signals SL, of the drive system30, which is controllable in automated fashion, using drive control signals SA, and of the brake system40, which is controllable in automated fashion, using braking control signals SB. Here, the relevant control signals SA, SB, SL are also generated in automated fashion by the control unit10in accordance with the path P. The infrastructure within the depot2ais used, that is to say obstructions H and other stationary or moving vehicles100are identified and taken into consideration, in the specification of the path P.

If no steering system20that is controllable in automated fashion is available in the vehicle1, because such a system is not present or has a defect, then in a first step ST1in the specification of the path P from the starting area4to the destination area5by the management system3, it is taken into consideration that steering of the vehicle1by setting of a particular steering angle d at the wheels7of the steered vehicle axle8is possible only in the context of a steering braking function.

In principle, the initial checking step ST0and the first step ST1for specifying the path P can also be performed by the control unit10itself, wherein, rather than drawing upon the infrastructure of the depot2a, a sensor system50having the sensor equipment in the vehicle1is used to plan and specify the path P. The vehicle information items I1, in particular the vehicle equipment specifications, are known to the control unit10itself, such that the planning and specification of the path P can also be performed from this aspect.

In a subsequent second step ST2, the control unit10will then, instead of the steering control signals SL for automated steering of the vehicle1, generate steering braking control signals SBL for the purposes of influencing the steering angle d of the wheels7of the steered vehicle axle8, with a drive control signal SA simultaneously also being generated, because steering braking is possible only whilst the vehicle1is traveling (forwards or backwards). Then, in a third step ST3, said generated steering braking control signals SBL and drive control signals SA are transmitted in automated fashion to the brake system40and to the drive system30, whereupon, whilst the vehicle1is in motion, wheel-specific control of the brakes9, in particular at the wheels7of the steered vehicle axle8, results in a particular steering moment L being exerted on the vehicle1, which steering moment, owing to the positive scrub radius at the wheels7of the steered vehicle axle8, cause said wheels7to turn by a particular steering angle d, causing the driven vehicle1to be steered.

The steering braking control signals SBL are generated such that a differential brake pressure dP is established at the wheels7of the steered vehicle axle8through wheel-specific control of the brakes9, wherein the brake pressure is ideally zero at one of the brakes9of the steered vehicle axle8so as not to exert undue load on the brakes9. Correspondingly to said differential brake pressure dP, a steering angle d is set at the wheels7of the steered vehicle axle8by way of the steering moment L that is established (and by way of the positive scrub radius), which steering angle in turn implements the steering specification at the relevant position of the path P in automated fashion. The specified path P can thus be traveled along through automated control of the brake system40, using the steering braking control signal SBL, and of the drive system30, using the drive signals SA. Braking or driving of the vehicle1is achieved here by way of a superposition of the drive control signal SA or of the braking control signal SB with the steering braking control signal SBL.

Since efficient steering of the vehicle1is possible to a lesser degree, or only up to a limit steering angle dG of for example 20°, by way of steering braking, this can be taken into consideration in the specification of the path P by the management system3in the first step ST1. Although steering angles d greater than a limit steering angle dG of 20° can be implemented by way of the described steering braking, this is possible only with increased wear of the respectively controlled brakes9. It can therefore also be taken into consideration that steering braking results in increased wear of the particular brakes9that are controlled for the purposes of steering braking. Accordingly, the path P can for example be specified such that it has only a small number of curve sections KA and/or has only curve sections KA with a low degree of curvature K, such that the differential brake pressure dP that is set, and accordingly also the absolute brake pressures at the relevant brakes9, are of lesser magnitude.

Under some circumstances, it is also necessary to take into consideration the specification of the destination area5at which, for example, a payload is to be picked up or set down. Here, it can for example be taken into consideration that, when resorting to steering braking in the manner described above, maneuvering of a vehicle1without a steering system30that is controllable in automated fashion to a free loading ramp5abetween two loading ramps5athat are already occupied by other vehicles100is highly complicated and is possible only with a large number of curve sections KA. Therefore, in this situation, the path P should be selected using a correspondingly different loading ramp5aas a destination area5, in the case of which fewer curve sections KA and/or curve sections KA with a lesser degree of curvature K are required.

Before or after the specification of the path P for the automated control of the vehicle1using the steering braking function (first step ST1), it is additionally possible for a vehicle mass M of the vehicle1to be acquired, for example from pressure information items from an air suspension system and/or from some other mass estimation, in order to allow the subsequent automated control of the vehicle1in accordance with this. In an intermediate step STZ, it is checked for this purpose whether the acquired vehicle mass M is higher than a limit mass MG of for example 31t. Only if the limit mass MG is undershot is automated generation of the steering braking control signal SBL and/or automated control of the brake system30using the steering braking control signal SBL subsequently allowed in the steps ST2and ST3. It is equivalently possible for the steering braking function to be permanently allowed, wherein the steering braking function is suppressed by the control unit10if the limit mass MG is overshot.

It is thus taken into consideration that implementation of the steering braking function in the case of very heavy vehicles1can lead to a very high degree of wear of the brakes9. In the case of a vehicle1having a vehicle mass M higher than the limit mass MG, the vehicle1can therefore be driven independently or manually within the depot2ato the destination area5. This is then for example a route on which the vehicle1is fully laden (incoming route before unloading at the destination area5or return route after loading at the destination area5), whereas the route before loading or after unloading could be covered in automated fashion if the vehicle mass M is lower than the limit mass MG.

When the path P is traveled along using the steering braking function, temperature monitoring can additionally be provided. For this purpose, a temperature sensor arrangement51is arranged at the brakes9. If a brake temperature T9of individual brakes9exceeds a temperature limit value TG, automated generation of the steering braking control signal SBL and/or automated control of the brake system30using the steering braking control signal SBL is disallowed, or the steering braking function is suppressed, in the steps ST2and ST3.

A steering braking duration tBL for which the brakes9are controlled for the purposes of implementing the steering braking function can additionally or alternatively be measured, for example by an automated function in the brake system30and/or by the control unit10. If a limit duration tG is overshot, then it is also the case independently of the level of the brake temperature T9that automated generation of the steering braking control signal SBL and/or automated control of the automated brake system30using the steering braking control signal SBL is disallowed, or the steering braking function is suppressed, in the steps ST2and ST3. Excessive wear is thus avoided irrespective of the brake temperature T9.

Instead of specifying the path P for maneuvering to a loading ramp5a, provision can also be made for unloading of bulk material at an unloading location15, wherein it is then also the case that the path P can be correspondingly selected under the above-described conditions with regard to steering braking.

Through corresponding control of the relevant system components20,30,40by the control unit10, the path P can be traveled in automated fashion, wherein the control unit10can use a sensor system50having the corresponding sensor equipment in the vehicle1to correspondingly monitor this automated journey, and can for example perform an actual-setpoint comparison of the position of the vehicle1and/or identify obstructions.

When the vehicle1has subsequently, in a fourth step ST4, arrived at the destination area5in the correspondingly intended pose (orientation, position), the relevant task can be performed, for example loading, unloading, servicing activities, etc., before the vehicle1is subsequently moved again on a specified path P to a further destination, or back to the original starting area4in order to exit the depot2a.

Instead of a depot2aas described, the method can also be implemented within a rest area as a confined site2, wherein the driver sets down the vehicle1at the rest area entrance (starting area4) and the vehicle1is subsequently maneuvered autonomously, using steering braking, into a free parking space16(destination area5) that can be reached using the steering braking function.

While subject matter of the present disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Any statement made herein characterizing the invention is also to be considered illustrative or exemplary and not restrictive as the invention is defined by the claims. It will be understood that changes and modifications may be made, by those of ordinary skill in the art, within the scope of the following claims, which may include any combination of features from different embodiments described above.

The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.

LIST OF REFERENCE DESIGNATIONS (PART OF THE DESCRIPTION)

1Vehicle1aTractor vehicle1bTrailer2Confined site2aDepot3Management system4Starting areaDestination area5aLoading ramp6Communication system6aWireless network7Wheel8Steerable vehicle axle9Brake10Vehicle control unit15Unloading location16Parking space20Steering system with automated control capability30Drive system with automated control capability40Brake system with automated control capability50Sensor system51Temperature sensor arrangement100Other vehiclesd Steering angledG Limit steering angledP Differential brake pressureH ObstructionM Vehicle massMG Limit massI1Vehicle information itemP PathK CurvatureKA Curve sectionL Steering momentSA Drive control signalSB Braking control signalSBL Steering braking control signaltBL Steering braking durationtG Limit durationT9Brake temperatureTG Limit temperatureST0, ST1, ST2, ST3, ST5, STZ Steps of the method