METHOD FOR DETERMINING THE VEHICLE MASS OF A SELF-PROPELLED VEHICLE, CENTRAL CONTROL UNIT AND SELF-PROPELLED VEHICLE

Description

[0001] The invention relates to a method for determining a vehicle mass of a self-propelled vehicle, in particular a commercial vehicle, a central control unit for carrying out the method, and a self-propelled vehicle with such a central control unit.

[0002] The availability of the most accurate possible vehicle mass of a self-driving vehicle, consisting of at least a towing vehicle and possibly at least one trailer or semi-trailer, is of great importance for the precise and safe planning and control of the target trajectory on which the autonomously operated vehicle is intended to move or is moving. To estimate the vehicle mass, a mass estimation algorithm is normally provided in a central brake control unit of an electronic braking system of the self-driving vehicle. Depending on the estimated vehicle mass, settings are then made in the brake management of the electronic braking system and, in particular, decisions are made regarding threshold values ​​of an RSC system (RSC, Roll Stability Control). The estimated vehicle mass is also used in the drive management of the self-driving vehicle.

[0003] The vehicle mass is traditionally estimated according to Newton's second law (F = M x A) while driving. The internal force (F), a driving force or a braking force, for example, is derived from engine torque, taking into account other vehicle parameters (e.g., the number of vehicle axles) as well as losses in the drive train or brake management, and the vehicle acceleration (A) is derived from the wheel speed of the wheels. Since the internal force in particular, but also the acceleration, depend on a number of unobserved influencing factors, this determination of the vehicle mass is subject to inaccuracies. Disturbances or disturbance forces can only be estimated in specific driving situations.

[0004] For example, DE 10 2008 037 083 A1 proposes to determine the vehicle mass from measured brake pressure and measured vehicle acceleration (deceleration), so that only a few error-prone parameters need to be used. EP 2 215 438 B1 proposes to estimate the vehicle mass based on weight classes into which the vehicle falls with the current load. EP 3 003 814 B1 further proposes to estimate the vehicle mass taking into account the power equation as a function of kinetic energy and drive power. The speed and drive power of the vehicle are to be determined at two consecutive points in time in time in order to be able to solve the power equation even with unknown driving resistances (gradient, rolling resistance, air resistance) and thus calculate out unknown inaccuracies.

[0005] In addition, continuous mass determination is usually provided, since, especially in manually operated vehicles, trigger events indicating a change in vehicle mass—in particular, a change in load in commercial vehicles—are not available or are not specifically used. Therefore, existing systems continuously assume that the vehicle mass may have changed, so that a current mass determination is also performed continuously.

[0006] To avoid this, DE 10 2019 103 968 A1 proposes using seat occupancy or seat belt restraint as vehicle operating information to determine a trigger event for a change in vehicle mass. In this case, the vehicle mass is re-determined. DE 10 2017 001 911 A1 also proposes comparing seat occupancy and / or fuel level and / or pitch angle of the vehicle before and after a stop and correcting the mass in the event of a significant deviation. An estimation of inaccuracies or disruptive forces is not performed. Based on the determined trigger event, the vehicle mass is simply re-determined using known algorithms.

[0007] Document GB 2 576 800 A discloses a self-propelled baggage cart.

[0008] Based on this, the object of the invention is to provide a method for estimating the mass of a self-driving vehicle, with which the vehicle mass can be estimated accurately and with minimal effort. A further object of the invention is to provide a central control unit and a self-driving vehicle.

[0009] This object is achieved by a method, a central control unit, and a self-driving vehicle according to the independent claims. The subclaims specify preferred developments.

[0010] According to the invention, a method is provided for determining a vehicle mass of a self-driving vehicle which is operated at least in automation level 4 or higher (according to the SAE J3016 standard), wherein in the method, in the presence of a trigger event which indicates a probable change in the vehicle mass, a learning operating mode is specifically activated, wherein the self-driving vehicle is specifically operated in the learning operating mode, for example for fixed periods of time, alternately in a first phase and in a second phase, wherein by means of an automated control of the electronic drive system and / or the electronic braking system - in the first phase, an internal force with a first force value, preferably a driving force via the electronic drive system or a deceleration force via the electronic braking system, and -- in the second phase, an internal force with a second force value is exerted on the self-driving vehicle, wherein the first force value differs from the second force value; and determining a disturbance force acting in the phases, wherein the disturbance force differs from the internal force that is actively caused, for example, by the drive or the brakes of the vehicle; and determining the vehicle mass as a function of the vehicle acceleration and the internal force that are present in each respective phase, as well as as a function of the determined or estimated disturbance force. The disturbance force can under certain circumstances be zero if no disturbance force acts on the self-driving vehicle in the respective phases.

[0011] According to the invention, a central control unit for carrying out the method according to the invention and a self-propelled vehicle with such a central control unit as well as an electronic braking system and an electronic drive system are further provided, in which the method according to the invention can be used.

[0012] Advantageously, in a self-driving vehicle operating at least at autonomy level 4, the sensor density and thus the information density are utilized to initially determine or evaluate whether the self-driving vehicle may have changed its mass during operation. Based on this evaluation or the presence of a trigger event, a learning operating mode can then be specifically initiated or activated to determine the mass of the self-driving vehicle as accurately as possible. This allows for good planning of the target trajectory, which is determined depending on the vehicle mass. However, even in current driving situations, unstable driving conditions can be detected and responded to more accurately and reliably if the exact vehicle mass is known.

[0013] Since the vehicle mass is only estimated upon triggering the event, processing effort is minimized. The invention takes advantage of the fact that the last determined vehicle mass in a self-driving vehicle does not need to be constantly validated or checked for changes. Due to the high sensor density in a self-driving vehicle, sufficient operating information is available that can indicate a change in the vehicle mass, so that a new determination of the vehicle mass only needs to be performed in such a case. Therefore, a constant questioning of the validity of the vehicle mass is not necessary in a self-driving vehicle.Nevertheless, it can be provided that at least a plausibility check of the vehicle mass takes place at regular intervals in the driving mode, which, however, does not take place through a targeted intervention in the electronic braking system and / or electronic drive system, but "incidentally" during normal driving operation.

[0014] In the learning mode, the vehicle's driving behavior is adjusted in the alternating first and second phases in such a way that unknown, undetermined, or undeterminable disturbance variables or forces can be estimated, allowing for the most accurate mass determination possible. This takes advantage of the fact that the learning mode in a self-driving vehicle can be specifically and appropriately integrated into the driving process by a central control unit, without being overridden by a manual driver or other automated instance. Therefore, activating the learning mode, in which a targeted switch is made between the first and second phases, does not disrupt the normal operation of the self-driving vehicle in a driving mode, and vice versa.

[0015] It is preferably provided that the first force value in the first phase or the second force value in the second phase is set to zero, so that in the first phase or in the second phase only a disturbing force acts on the self-driving vehicle. In this way, in the respective phase in which an internal force is deliberately set to zero, i.e. no drive power or no deceleration power is acting, it can be estimated directly from the then existing vehicle reaction, in particular the then existing vehicle acceleration, which disturbing forces are acting on the self-driving vehicle, since these alone then ensure vehicle acceleration. This enables a simple quantitative estimation of the disturbing forces, which can then subsequently be used in the other phase for the mass estimation.

[0016] Preferably, it is further provided that an automated control of the electronic drive system and / or the electronic braking system, when the learning operating mode is activated, for setting a first force value or a second force value of zero in the respective phase takes place in such a way that a drive train of the self-propelled vehicle is opened, for example by targeted disengagement, and / or any brakes of the self-propelled vehicle are released. Accordingly, the vehicle acceleration will only be changed by disruptive forces, in particular forces acting externally on the self-propelled vehicle, e.g., a downhill force, air resistance, etc., or forces acting within the self-propelled vehicle, e.g., internal frictional forces of the drive components or a static frictional force on the road surface.In this simple way, a passive driving condition can be specifically created in order to estimate the disturbing forces in the respective phase, for example from the vehicle acceleration then acting.

[0017] In the first phase, a first acceleration value for the vehicle's acceleration is established based on the setting of the first force value and the presence of a disturbing force. In the second phase, a second acceleration value for the vehicle's acceleration is established based on the setting of the second force value and the presence of a disturbing force. The respective force and acceleration values, except for the disturbing force, can be easily determined in the respective phase using corresponding sensors in the vehicle or provided by the respective control units of the electronic drive system or braking system in the self-driving vehicle, thus eliminating the need for additional sensors.

[0018] Based on this, it is further provided that in order to determine the vehicle mass, an average mass value characterizing the vehicle mass is determined from individual mass values, wherein at least one individual mass value is assigned to each phase in which the first force value and / or the second force value is not equal to zero, wherein the individual mass values ​​follow from the first force value or second force value present in the respective phase and the first or second acceleration value present in the respective phase, taking into account a disturbance force value, preferably from Newton's second law.

[0019] Therefore, a vehicle mass can be easily determined from the force and acceleration values ​​determined in the respective phases, for example, by averaging, which also takes into account the disturbing forces acting in the respective phases, making the mass determination more accurate. For a phase with a force value of zero, the disturbing force value is preferably derived directly from the vehicle acceleration present in that phase. For alternating first and second phases without a force value of zero, it is determined by comparing the vehicle accelerations present in the respective phases, since the disturbing force influences the vehicle acceleration equally in both phases.

[0020] Preferably, it is further provided that an individual mass value is determined as a function of a disturbance force value that characterizes the disturbance force in a phase immediately preceding the phase assigned to the individual mass value. Therefore, the individual mass values ​​are calculated based on a disturbance force that is highly likely to still be present in the respective assigned phase. This makes the determination of the individual mass values ​​more accurate overall.

[0021] Preferably, the learning operating mode remains activated until individual mass values ​​assigned to different phases are within a tolerance value around the average mass value. This allows deviations that occur, for example, due to temporarily occurring disruptive forces, such as short gusts of wind or short road gradients, to be filtered out, as these are less significant when averaging over a longer period of time.

[0022] Preferably, it can further be provided that the learning operating mode remains activated until the disturbance force values ​​determined in different phases differ from each other by less than a threshold value. Therefore, the determined disturbance forces can also be directly compared with each other to determine whether only short-term disturbance forces occur, and in this case, the learning operating mode can be extended.

[0023] Preferably, the learning operating mode remains active for at least two first phases and at least two second phases, each alternating. This number of first and second phases ensures at least a reliable determination of the vehicle mass, taking into account the disturbing forces.

[0024] Preferably, it is further provided that the determination of whether a trigger event is present is carried out as a function of operating information of the self-driving vehicle, wherein the operating information includes at least one element selected from the group consisting of: trailer status change information indicating whether a trailer coupling of the autonomous vehicle has been switched between an open position and a closed position in order to infer from this whether the vehicle mass has likely changed due to coupling or uncoupling of a trailer; and / or load opening status change information indicating whether a loading opening to a load compartment of the autonomous vehicle has been opened or closed in order to infer from this whether the vehicle mass has most likely changed due to loading or unloading of a load via the respective loading opening;and / or level change information indicating whether a distance between at least one of the vehicle axles and a vehicle frame of the self-driving vehicle has changed, in order to deduce from this whether the vehicle mass has most likely changed due to a change in the load on the vehicle frame; and / or planned loading information indicating whether and when a scheduled pick-up or drop-off of a load by the self-driving vehicle should occur, in order to deduce from this whether the vehicle mass has most likely changed due to, for example, a loading or unloading planned by the fleet operator;and / or loading activity information indicating whether loading activities are being detected in the environment of the self-driving vehicle, for example via a sensor arrangement which, for example, has a camera, via which loading activities of, for example, people and / or industrial trucks in the environment can be detected, in order to deduce from this whether the vehicle mass has most likely changed due to loading or unloading; and / or loading loss information indicating whether an unintentional loss of cargo has been detected by the self-driving vehicle, for example while driving, for example via a sensor arrangement which, for example, has a camera that can detect a loss of cargo from the self-driving vehicle, in order to deduce from this whether the vehicle mass has most likely changed due to a lost cargo;and / or remote information indicating whether a load pickup or drop-off by the self-driving vehicle was wirelessly communicated via a cloud system or another wireless remote system, in order to deduce whether the vehicle mass has most likely changed due to loading or unloading; and / or position information indicating whether the self-driving vehicle is outside of public road traffic, e.g. at a depot, in order to deduce whether the vehicle mass has most likely changed due to loading or unloading, in particular if the current position of the self-driving vehicle indicates a possibility of loading or unloading.

[0025] Therefore, a range of operating information is available in the self-driving vehicle, which can be used alone or in combination to determine a trigger event. Preferably, the operating information is used to assess whether a change in the vehicle mass is likely, and a trigger signal is output if the operating information determines that a change in the vehicle mass is likely. The trigger signal is used to determine whether a trigger event has occurred.

[0026] The invention is explained in more detail below with reference to the figures. They show: Fig. 1 shows a schematic view of a vehicle; Fig. 2 shows a flowchart of the method according to the invention; and Fig. 3 shows a temporal overview of the learning operating mode.

[0027] Figure 1shows a schematic of an autonomously operated or self-driving vehicle 1, consisting of a towing vehicle 1a and a semi-trailer 1b. The self-driving vehicle 1 is intended to be operated at an automation level of 4 or higher (according to the SAE J3016 standard), meaning that a driver does not necessarily have to be present or attentive. The self-driving vehicle 1 can, in principle, also be a single-unit vehicle or, as a multi-unit vehicle, consist of a towing vehicle 1a with one or more trailers (drawbar trailers, etc.) or semi-trailers 1b.

[0028] The self-driving vehicle 1 has an electronic braking system 2, an electronic drive system 3, and an electronic steering system 4, via which the self-driving vehicle 1 can be automatically braked, driven, or steered, respectively. A central control unit 5 (Virtual Driver) is provided to control the individual electronic systems 2, 3, 4. In a driving operating mode FB, the central control unit 5 is configured to determine and / or read in a target trajectory Ttarget and to guide the self-driving vehicle 1 along this target trajectory Ttarget by controlling the electronic systems 2, 3, 4.

[0029] The self-propelled vehicle 1 further comprises a mass estimation unit 7, arranged, for example, in the towing vehicle 1a, which is configured to estimate a vehicle mass M of the self-propelled vehicle 1 and output a corresponding mass estimate MW. The vehicle mass M refers in this case to the entire self-propelled vehicle 1 comprising all vehicle parts (towing vehicle 1a and semi-trailer 1b or additional trailers / semi-trailers). The mass estimation unit 7 can, for example, be integrated into the central control unit 5, for example as software or an algorithm. Similarly, the mass estimation unit 7 can also be connected to the central control unit 5 in a signal-conducting manner and / or integrated into one of the electronic systems 2, 3, 4, so that the mass estimate MW can also be transmitted externally to the central control unit 5.

[0030] The central control unit 5 can use the estimated mass value MW, in particular, to determine the target trajectory Ttarget and / or also when following the target trajectory Ttarget, in order to proactively avoid stability-critical situations in autonomous driving mode and / or in the current driving situation. To ensure the best possible planning in fully automated driving mode and to be able to accurately evaluate the current driving situation with regard to driving stability, the vehicle mass M must be determined as accurately as possible by the mass estimation unit 7.

[0031] The mass estimation unit 7 estimates the vehicle mass M based on Newton's second law F = M x A, where F is an internal force with which the self-propelled vehicle 1 is driven or decelerated in order to accelerate the vehicle mass M with a vehicle acceleration A (positive or negative) oriented in the longitudinal direction L of the self-propelled vehicle 1. Therefore, either a driving force FA or a deceleration force FV can act on the self-propelled vehicle 1, which influences the internal force F in the above formula.

[0032] In the driven case, the driving force FA results, for example, from an engine torque D generated by the drive 30 of the electronic drive system 3, taking into account losses V that normally occur in a drive train 35 of the self-propelled vehicle 1, which are preferably known. The engine torque D or a related variable can be transmitted, for example, from a drive controller 31 (engine electronics) of the electronic drive system 3, for example via a data bus of the self-propelled vehicle 1, to the mass estimation unit 7 in the central control unit 5. Depending on this, and taking into account the known losses V in the drive train 35, the mass estimation unit 7 can determine a (positive) force value FW, which characterizes the driving force FA in the driven case.

[0033] In the braking case, the deceleration force FV or a (negative) force value FW results, for example, from the activation times of the individual brakes 20 (service brake 20a, continuous brake 20b, engine brake 20c, etc.) generated in a brake control 21 of the electronic braking system 2 and / or from brake signals SB output by the brake control 21 of the electronic braking system 2 to the individual brakes 20 in order to decelerate the self-driving vehicle 1 as requested. Therefore, variables characterizing the current deceleration force FV can also be transmitted from the brake control 21, for example, via the data bus, to the mass estimation unit 7 in the central control unit 5.

[0034] The vehicle acceleration A can be characterized by an acceleration value AW, which results, for example, from the calculated wheel accelerations A8 of the individual wheels 8 of the self-propelled vehicle 1. For this purpose, the wheel speeds N are determined individually by wheel speed sensors 9 on the respective wheels 8 of the self-propelled vehicle 1, and the individual wheel accelerations A8 are calculated from these by mathematical derivation. The vehicle acceleration A or the acceleration value AW is then determined, for example, by calculating an average value (arithmetic mean) across all or some of the wheels 8.

[0035] The vehicle mass M is estimated in the mass estimation unit 7, for example, by determining the mass of the vehicle in a determination step STE (cf. Fig. 2) individual mass values ​​MWi, with i = 1, 2, 3, ... p (p = number of individual values) are continuously calculated, which follow from the current driving situation using the formula M = F / A. Subsequently, a mass mean value MWM (arithmetic mean) is calculated from the individual mass values ​​MWi determined at different times t, whereby the mass mean value MWM indicates the mass estimate MW to be output. As a result of the averaging, the mass estimate MW approaches the actual vehicle mass M of the self-driving vehicle 1 with an increasing number p of individual mass values ​​MWi.

[0036] In order to carry out this determination process as precisely as possible, the individual mass values ​​MWi are determined in a learning operating mode EB, which can be specifically set or activated by the central control unit 5 in an activation step STA if a trigger event TE, which will be explained in more detail later, occurs. If such a trigger event TE does not occur, the self-driving vehicle 1 continues to operate in the drive operating mode FB. In the learning operating mode EB, the first phases P1 and the second phases P2 alternate specifically, with the central control unit 5 controlling the electronic drive system 3 and / or the electronic braking system 2 for this purpose according to Fig. 3 in first time periods dt1 to set the first phases P1 and in second time periods dt2 to set the second phases P2, or specifically suspends a control.

[0037] In the first phase P1, the self-propelled vehicle 1 is actively driven with a defined internal force F, i.e. drive force FA or deceleration force FV, via the drive 30 or actively decelerated via the respective brakes 20 (service brakes 20a, continuous brakes 20b, engine brakes 20c, etc.). In the first phase P1, a specific first force value FW1 characterizing the internal force F is present. In the second phase P2, the self-propelled vehicle 1 is also operated with a defined internal force F, wherein in the second phase P2, a specific second force value FW2 characterizing the internal force F is present, which explicitly differs from the first force value FW1.The self-driving vehicle 1 is therefore operated differently in both phases P1, P2, whereby in the first phase P1 a first acceleration value AW1 characterizing the vehicle acceleration A in this first phase P1 is established and in the second phase P2 a second acceleration value AW2 characterizing the vehicle acceleration A in this second phase P2 is established.

[0038] In a preferred embodiment, the second force value FW2 is zero in the second phase P2, i.e., the self-propelled vehicle 1 is not actively driven via the drive 30 or actively braked via the respective brakes 20 in the second phase P2. For this purpose, the drive control 31 or the electronic drive system 2 and / or the brake control 21 or the electronic brake system 3 are controlled by the central control unit 5 in the second phase P2 in such a way that, for example, the drive train 35 is opened by disengaging the clutch or the respective brakes 20 are released.

[0039] In the second phase P2, according to the preferred embodiment, a defined driving state is created in which the vehicle acceleration A of the self-driving vehicle 1 changes only as a function of unknown disturbance forces FS, if any are present. If, for example, a vehicle acceleration A or a second acceleration value AW2 is non-zero in the second phase P2, a (positive or negative) disturbance force FS or a disturbance variable characterizing it can be derived therefrom, which is responsible for the change in movement (propulsion or deceleration) of the self-driving vehicle 1 in the second phase P2.

[0040] A (positive or negative) disturbance force FS can, for example, be caused by an incline (gradient, incline) along which the self-driving vehicle 1 is moving, or by the effect of wind (from the front or rear) or other external forces acting on the self-driving vehicle 1. Furthermore, disturbance forces FS can also be frictional forces that act, for example, on the moving drive components in the self-driving vehicle 1 and / or that act on the road surface due to a specific tire condition (static friction forces). These disturbance forces FS can either not be determined at all or not always accurately by sensors in the self-driving vehicle 1. However, the second phase P2 with a defined second force value FW2 of zero enables a direct estimation of these disturbance forces FS, which can be processed into a corresponding disturbance force value FWS by the mass estimation unit 7.

[0041] In the first phase P1, a driving state is created in which the vehicle acceleration A of the self-propelled vehicle 1 changes as a result of the known or defined internal forces F or the defined first force values ​​FW1 (positive or negative) by the drive 30 or the brakes 20, but also as a function of the unknown disturbance forces FS, if present. Assuming that the disturbance forces FS do not change significantly in the immediately successive phases P1, P2, the disturbance forces FS or the disturbance force value FWS directly determined or estimated in the second phase P2 can be specifically taken into account in the determination step STE, in which the individual mass values ​​MWi are estimated based on the first force values ​​FW1 and the first acceleration values ​​AW1 available in the first phase P1 for different times t.Thus, in the determination step STE, the individual mass values ​​are determined, for example, via MWi = (FW1 + FWS) / AW1, ie from the vehicle acceleration A of the self-driving vehicle 1 caused by the known and unknown forces F, FS.

[0042] If the second force value FW2 is not zero in the second phase P2, the disturbance force FS cannot be estimated directly from the second acceleration value AW2, but at least from the difference between the first acceleration value AW1 in the first phase P1 and the second acceleration value AW2 in the second phase P2, taking into account the respectively set force values ​​FW1, FW2, although here again it is assumed that the disturbance forces FS are approximately identical in both phases P1, P2. Therefore, the disturbance forces FS or a disturbance force value FWS are determined after a first and a second phase P1, P2 have been completed at least once.

[0043] By repeatedly switching between the first phase P1 and the second phase P2 by the central control unit 5, rapidly changing disturbing forces FS, such as temporary gusts of wind, can also be detected and taken into account. If the individual mass values ​​MWi, which were determined over several consecutive first phases P1 or second phases P2, in which the second force values ​​FW2 are not equal to zero, based on the disturbing forces FS from the respective preceding phases P1, P2, deviate from each other by a certain tolerance value TW, for example, the teach-in operating mode EB can be extended accordingly until the individual mass values ​​MWi are within a certain tolerance or the mass dispersion is minimized.According to an equivalent alternative, the estimated disturbance forces FS from successive phases P1 and P2 can also be compared with each other, and in the event of deviations above a limit value GW, an extension of the teach-in operating mode EB can be provided. This filters out briefly occurring disturbance forces FS that only act in the second phase P2 and not completely in the first phase P1 (or vice versa). This makes the mass determination more accurate overall.

[0044] In contrast to manual driving, e.g. in autonomy level 2, the activation of the learning operating mode EB by the central control unit 5 can be carried out in such a way that no unwanted or disruptive effect on normal driving occurs, since it can be planned accordingly by the virtual driver or the central control unit 5 and during this time no override normally occurs, which simplifies the learning process overall.

[0045] As already mentioned, the learning operating mode EB is activated in the activation step STA only when a trigger event TE occurs. This occurs, for example, when an evaluation unit 15, which can be integrated, for example, in the mass estimation unit 7, has classified a change in the vehicle mass M as probable in an evaluation step STB. If this is the case, a trigger signal ST can be output by the evaluation unit 15, whereupon the central control unit 5 activates the learning operating mode EB in the activation step STA and, by electrically controlling the electronic systems 2, 3, 4, alternately implements the respective phases P1, P2 in the respective time periods dt1, dt2 as described above.

[0046] In the evaluation step STB, to determine whether a change in the vehicle mass M is likely or whether a trigger event TE is present, the evaluation unit 15, for example, uses operating information I that is already recorded and used for the operation of the self-driving vehicle 1 and is therefore available without restriction. This operating information I can, for example, be: Trailer status change information I1, which indicates whether a trailer coupling 17 (fifth wheel coupling, drawbar coupling, etc.) of the self-propelled vehicle 1 has been switched between an open position 170 and a closed position 17G (or vice versa), from which it can be deduced that the vehicle mass M has most likely changed due to coupling or uncoupling of the trailer 1b; and / or loading opening status change information I2, which indicates whether a loading opening 27, for example a loading door, a roller shutter, etc. to the loading space 28, has been opened and / or closed, from which it can be deduced that the vehicle mass M has most likely changed due to loading or unloading of a load 19 via the respective loading opening 27;and / or level change information I3, which indicates whether a distance between at least one of the vehicle axles 18 and a vehicle frame 13 of the self-propelled vehicle 1 has changed, from which it can be deduced that the vehicle mass M has most likely changed due to a change in the load on the vehicle frame 13; and / or planned loading information I4, which indicates whether and when a scheduled pick-up or drop-off of a load 19 by the self-propelled vehicle 1 should occur, from which it can be deduced that the vehicle mass M has most likely changed due to a planned loading or unloading;and / or loading activity information I5, which indicates whether loading activities LT are detected in the environment U of the self-driving vehicle 1, wherein this can be done, for example, using sensors of a sensor arrangement 6, which, for example, has a camera 6a as a sensor, which can detect loading activities LT of, for example, persons and / or industrial trucks, from which it can be deduced that the vehicle mass M has most likely changed due to loading or unloading;and / or charge loss information I6, which indicates whether an unintentional loss of charge 19 was detected, for example, during the journey. This can be done, for example, using sensors of a sensor arrangement 6 in the self-driving vehicle 1, which, for example, has a camera 6a as a sensor that can detect a loss of charge 19, from which it can be deduced that the vehicle mass M has most likely changed due to a lost charge 19; and / or remote information I7, which indicates whether a pickup or release of charge 19 was wirelessly communicated via a cloud system C or another wireless remote system R, from which it can be deduced that the vehicle mass M has most likely changed due to loading or unloading.and / or position information I8 indicating whether the self-driving vehicle 1 is outside of public road traffic Ö, e.g. at a depot, from which it can be deduced that the vehicle mass M has most likely changed due to loading or unloading, in particular if the current position indicates a possibility of loading or unloading. ;

[0047] Depending on the respective operating information(s) I that is / are available to the evaluation unit 15 and that is / are provided, for example, via corresponding signals in the self-driving vehicle 1, the probability of a change in the vehicle mass M is evaluated in the evaluation step STB, and a trigger signal ST is then output if the evaluation indicates a mass change event or a significant or relevant change in the vehicle mass M. Accordingly, the vehicle mass M is not continuously determined in the manner described. Continuous validation of the exact vehicle mass M during the journey is therefore not provided, so that the mass determination is simplified overall.

[0048] However, a rough plausibility check of the vehicle mass M can be performed at regular intervals even when the drive operating mode FB is activated. For example, by determining a disturbance force FS during load breaks, e.g., during a gear change, and using this force to at least estimate individual mass values ​​MWi during load phases using Newton's second law. However, this plausibility check does not involve active intervention in the driving process, as in the learning operating mode FE. List of reference symbols (part of the description)

[0049] 1Vehicle 1aTowing vehicle 1bTrailer 2Electronic braking system 3Electronic drive system 4Electronic steering system 5Central control unit 6Sensor arrangement 6aCamera 7Mass estimation unit 8Wheel of the self-propelled vehicle 1 9Wheel speed sensor 15Evaluation unit 17Trailer coupling 170Open position of the trailer coupling 17 17GClosed position of the trailer coupling 17 18Vehicle axle 19Load 20Brake 20aService brake 20bContinuous brake 20cEngine brake 21Brake control 27Loading opening 28Loading space 30Drive 31Drive control 35Drivetrain AVehicle acceleration A8Wheel acceleration AWAcceleration value AW1First acceleration value AW2Second acceleration value CCloud system dt1First period dt2 second period DRoms EBLearning operating mode FInternal force FADrive force FBTravel operating mode FSDisturbance force FVDeceleration force FWForce value FW1First force value FW2Second force value FWSDisturbance force value GWLimit value IOperating informationI1Trailer status change information I2Load opening status change information I3Level change information I4Planned loading information I5Loading activity information I6Loading loss information I7Remote information I8Position information LLongitudinal direction LTLoading activity MVehicle mass MWMass estimate MWiIndividual mass value MWMMass average NWheel speed ÖPublic road traffic pIndex P1First phase P2Second phase RRemote system SBBraking signal STTrigger signal tTime point TSollTarget trajectory TETrigger event TWTolerance value LValues ​​in the drive train 35 STB, STA, STESteps of the procedure

Claims

1. Method for determining a vehicle mass (M) of a self-driving vehicle (1), wherein an internal force (F) can be exerted on the self-driving vehicle (1) by automated control of an electronic drive system (3) which has a drive (30) and / or of an electronic braking system (2) which has brakes (20), comprising at least the following steps: - identifying whether a trigger event (TE) is present, wherein the trigger event (TE) indicates that a change in the vehicle mass (M) of the self-driving vehicle (1) is likely, and - activating a learning operating mode (EB) when a trigger event (TE) is present (STA), wherein the self-driving vehicle (1) is operated in the learning operating mode (EB) alternately in a first phase (P1) and in a second phase (P2), wherein by automated control of the electronic drive system (3) and / or of the electronic braking system (2) -- in the first phase (P1) an internal force (F) which has a first force value (FW1), and -- in the second phase (P2) an internal force (F) which has a second force value (FW2) is exerted on the self-driving vehicle (1), wherein the first force value (FW1) differs from the second force value (FW2); - determining a disturbing force (FS) acting in the phases (P1, P2); and - determining the vehicle mass (M) (STE) on the basis of a vehicle acceleration (A) and the internal force (F), which are each present in the relevant phase (P1, P2), as well as on the basis of the determined disturbing force (FS).

2. Method according to claim 1, characterized in that the first force value (FW1) in the first phase (P1) or the second force value (FW2) in the second phase (P2) is set to zero, so that in the first phase (P1) or in the second phase (P2) only a disturbing force (FS) acts on the self-driving vehicle (1).

3. Method according to claim 2, characterized in that automated control of the electronic drive system (3) and / or of the electronic braking system (2) takes place, when the learning operating mode (EB) is activated for setting a first force value (FW1) or a second force value (FW2) of zero in the relevant phase (P1, P2), in such a way that a drive train (35) of the self-driving vehicle (1) is opened and / or any brakes (20) of the self-driving vehicle (1) are released.

4. Method according to any of the preceding claims, characterized in that the electronic drive system (3) and / or the electronic braking system (2) is or are specifically controlled, when the learning operating mode (EB) is activated, by a central control unit (5) in the first phase (P1) for a specified first period of time (dt1) and in the second phase (P2) for a specified second period of time (dt2) in order to set an internal force (F) which has the first force value (FW1), e.g. not equal to zero, in the first phase (P1), and an internal force (F) which has the second force value (FW1), e.g. zero, in the second phase (P2).

5. Method according to any of the preceding claims, characterized in that the electronic drive system (3) and / or the electronic braking system (3) is controlled, when the learning operating mode (EB) is activated for setting a first force value (FW1) and / or a second force value (FW2) not equal to zero in the relevant phase (P1, P2), in such a way that a drive force (FA) or a deceleration force (FV) acts on the self-driving vehicle (1) as the internal force (F).

6. Method according to any of the preceding claims, characterized in that in the first phase (P1), a first acceleration value (AW1) for the vehicle acceleration (A) is set due to the setting of the first force value (FW1) and the presence of a disturbing force (FS), and in the second phase (P2), a second acceleration value (AW2) for the vehicle acceleration (A) is set due to the setting of the second force value (FW2) and the presence of a disturbing force (FS).

7. Method according to claim 6, characterized in that, in order to determine the vehicle mass (M), an average mass value (MWM) characterizing the vehicle mass (M) is ascertained from single mass values (Mwi), at least one single mass value (Mwi) being assigned to each phase (P1, P2) in which the first force value (FW1) and / or the second force value (FW2) is not equal to zero, the single mass values (MWi) resulting from the first force value (FW1) or second force value (FW2) present in the relevant phase (P1, P2) and the first acceleration value (AW1) or second acceleration value (AW2) present in the relevant phase (P1, P2), taking into account a disturbing force value (FSW), the disturbing force value (FSW) characterizing the disturbing force (FS).

8. Method according to claim 7, characterized in that the disturbing force value (FSW) - results from the first acceleration value (AW1) if the first force value (FW1) in the first phase (P1) is zero, or - results from the second acceleration value (AW2) if the second force value (FW2) in the second phase (P1) is zero, or results from the first acceleration value (AW1) and the second acceleration value (AW2) if the first and the second force value (FW1, FW2) are not equal to zero.

9. Method according to claim 7 or claim 8, characterized in that a single mass value (MWi) is ascertained on the basis of a disturbing force value (FSW) which characterizes the disturbing force (FS) in a phase (P2, P1) which lies immediately before the phase (P1, P2) assigned to the single mass value (MWi).

10. Method according to any of claims 7 to 9, characterized in that the learning operating mode (EB) remains activated until single mass values (MWi) assigned to different phases (P1, P2) lie within a tolerance value (TW) around the average mass value (MWM).

11. Method according to any of claims 7 to 10, characterized in that the learning operating mode (EB) remains activated until disturbing force values (FSW) determined in different phases (P1, P2) deviate from each other by less than a limit value (GW).

12. Method according to any of the preceding claims, characterized in that the learning operating mode (EB) remains activated for at least two first phases (P1) and at least two second phases (P2), which alternate.

13. Method according to any of the preceding claims, characterized in that determining whether a trigger event (TE) is present is carried out on the basis of operating information (I) of the self-driving vehicle (1), the operating information (I) containing at least one element selected from the group consisting of: - trailer status change information (11) indicating whether a trailer coupling (17) of the self-driving vehicle (1) has been switched between an open position (170) and a closed position (17G); and / or - loading opening status change information (I2) indicating whether a loading opening (27) to a loading space (28) of the self-driving vehicle (1) has been opened or closed; and / or - level change information (I3) indicating whether a distance between at least one of the vehicle axles (18) and a vehicle frame (13) of the self-driving vehicle (1) has changed; and / or - planned load information (I4) indicating whether and when a load (19) should be picked up or delivered by the self-driving vehicle (1) as planned; and / or - loading activity information (I5) indicating whether loading activities (LT) are perceived in a vicinity (U) of the self-driving vehicle (1), this taking place, for example, via a sensor arrangement (6) which, for example, has a camera (6a) via which loading activities (LT) in the vicinity (U) can be perceived; and / or - loading loss information (I6) indicating whether an unwanted loss of a load (19) from the self-driving vehicle (1) was perceived, for example during the journey, this taking place, for example, via a sensor arrangement (6) which, for example, has a camera (6a) which can perceive a loss of the load (19) from the self-driving vehicle (1); and / or - remote information (I7) indicating whether a pickup or delivery of a load (19) by the self-driving vehicle (1) was communicated wirelessly via a cloud system (C) or another wireless remote system (R); and / or - position information (I8) indicating whether the self-driving vehicle (1) is outside public roads (Ö) (e.g. at a depot).

14. Method according to claim 13, characterized in that on the basis of the operating information (IB), it is assessed (STB) whether a change in the vehicle mass (M) is likely, and a trigger signal (ST) is issued if it is established that a change in the vehicle mass (M) is likely, the trigger signal (ST) being the basis on which it is determined whether a trigger event is present.

15. Central control unit (5) for carrying out a method according to any of the preceding claims.

16. Self-driving vehicle (1) which has a central control unit (5) according to claim 15, an electronic braking system (2) and an electronic drive system (3), wherein the central control unit (5) is designed to control the electronic braking system (2) and the electronic drive system (3), when a trigger event (TE) is present, in an activated learning operating mode (EB) such that the self-driving vehicle (1) is operated alternately in a first phase (P1) and in a second phase (P2), wherein by automated control of the electronic drive system (3) and / or the electronic braking system (2) by the central control unit (5) -- in the first phase (P1) an internal force (F) which has a first force value (FW1) can be set on the self-driving vehicle (1), and -- in the second phase (P2) an internal force (F) which has a second force value (FW2) can be set on the self-driving vehicle (1), wherein the first force value (FW1) differs from the second force value (FW2); and the central control unit (5) is designed to determine a disturbing force (FS) acting in the relevant phase (P1, P2) and to determine a vehicle mass (M) on the basis of the vehicle acceleration (A) and the internal force (F), which are each present in the relevant phase (P1, P2), as well as on the basis of the disturbing force (FS).