Method and device for determining parameters relevant to braking behavior

Abstract

The invention relates to a method for determining at least one parameter relevant to braking behavior, applicable to the open-loop or closed-loop control of a braking system (210) of a railway vehicle (200). According to the invention, a physical model (PHYSM) is used to determine this parameter, taking into account the influence of a wheel (10) preceding the wheel (20) to be braked, specifically with regard to the influence effect that the preceding wheel (10) exerts on the traction between the rear wheel (20) to be braked and the rail (30).

Description

[0001] The invention relates to a method for determining at least one parameter relevant to the braking behavior of a rail vehicle's braking system, wherein a physical model is used to determine the at least one parameter relevant to the braking behavior, which takes into account the influence of a wheel preceding a wheel to be braked, specifically with regard to an influencing effect that the preceding wheel exerts on the frictional connection between the trailing wheel to be braked and the rail.

[0002] A generic method is known from publication WO 2017 / 175108 A1, which is directed to a method for controlling and restoring the traction of wheels belonging to at least two controlled axles of a railway vehicle during a wheel slip phase, comprising the following steps: Generating speed signals indicating the angular velocity of the wheels; estimating the instantaneous adhesion value at the contact point between the wheels and the rails using an adhesion monitoring device; generating a target slip value for the wheels of at least two axles using an optimization algorithm that processes the estimated adhesion values ​​and continuously changes the target slip value over time, with a predetermined sampling period, to maximize the average value of the vehicle's wheel adhesion.

[0003] In the field of railway vehicle technology, it is common practice to use so-called Hardware-in-the-Loop (HiL) test benches as a dynamic test environment for vehicle software. This combines the actual control system hardware with vehicle models. To implement realistic boundary conditions for drive / brake scenarios, the most accurate possible braking behavior-relevant parameters must be considered in the simulation. For example, for simulating anti-slip test runs, which can also be used as type approval tests, the test conditions of EN15595 should be replicated as realistically as possible.

[0004] Furthermore, European patent EP 3 331 736 B1 discloses a method and a system for commissioning a braking system with predefined approval requirements. In this previously known method, a virtual control data set is checked using a virtual test run to determine to what extent it needs to be modified so that the braking system meets the predefined approval requirements.

[0005] The invention is based on the objective of providing a very precise method for determining at least one parameter relevant to braking behavior.

[0006] This problem is solved according to the invention by a method with the features according to claim 1. Advantageous embodiments of the method according to the invention are specified in the dependent claims.

[0007] According to the invention, the physical model takes into account the influence of fluid on a rail traversed by the wheel to be braked, by including a quantity of fluid acting on the wheel to be braked, wherein the quantity of fluid acting on the wheel to be braked is calculated taking into account a fluid reduction caused by the preceding wheel.

[0008] A significant advantage of the method according to the invention is that it enables the very precise determination of braking behavior-relevant parameters, even in cases where, for example, a water / soap mixture is deliberately sprayed onto railway tracks for testing purposes in order to replicate predetermined test scenarios according to approval standards; because, according to the invention, a conditioning effect that is very relevant in such cases and that one or more leading wheels can exert on a wheel to be braked is specifically taken into account.

[0009] Based on the braking behavior-relevant parameters determined using the inventive method, it is advantageously possible, for example, to simulate very realistic anti-slip test drives according to the EN15595 standard, which in turn allows for a significant reduction in complex and expensive real vehicle tests for both initial commissioning and acceptance tests.

[0010] Fluid reduction can be caused, for example, by friction of the leading wheel on the rail being traveled on, or by fluid adhering to or remaining on the rotating leading wheel.

[0011] Based on the physical model, a first auxiliary characteristic curve, which describes a frictional connection as a function of slip on a dry rail, and a second auxiliary characteristic curve, which describes the frictional connection as a function of slip on a wet rail, are preferably defined for the rail vehicle.

[0012] By including the first and second auxiliary characteristic curves and a moisture value indicating the amount of fluid on the rail during braking, a friction characteristic curve lying between the first and second auxiliary characteristic curves is preferably determined, which describes the actual friction, which forms the or at least one of the braking behavior-relevant parameters to be determined, over time.

[0013] The friction characteristic curve is determined in a particularly advantageous manner according to: Fx t = Fw t ⋅ HK 1 Cx t + 1 − Fw t ⋅ HK 2 Cx t where HK1 describes the first auxiliary characteristic curve as a function of the time-dependent slip Cx(t), HK2 describes the second auxiliary characteristic curve as a function of the time-dependent slip Cx(t) and Fw describes the moisture value.

[0014] The first auxiliary characteristic curve HK1 is preferably determined according to HK 1 = M 1 t ⋅ Ka ⋅ E 1 t , Q t / 1 + E t , Q t 2 + atan Ks ⋅ E 1 t , Q t / Pi where Ka is a dimensionless reduction factor in the adhesion region of the wheel / rail contact area, Ks is a dimensionless reduction factor in the sliding region of the wheel / rail contact area, Q(t) is the wheel contact force of the wheel to be braked on a rail, M1(t) is a first auxiliary function of the first auxiliary characteristic curve, and E1(t,Q(t)) is a second auxiliary function of the first auxiliary characteristic curve.

[0015] The second auxiliary characteristic curve HK2 is preferably determined according to HK 2 = M 2 t ⋅ Ka ⋅ E 2 t , Q t / 1 + E 2 t , Q t 2 + atan Ks ⋅ E 2 t , Q t / Pi where M2(t) describes a first auxiliary function of the second auxiliary characteristic curve and E2(t,Q(t)) describes a second auxiliary function of the second auxiliary characteristic curve.

[0016] Preferably, the frictional contact between the wheel to be braked and a railway track to be traversed is determined as a braking behavior-relevant parameter or at least one of the braking behavior-relevant parameters.

[0017] As a braking behavior-relevant parameter, or at least one of the braking behavior-relevant parameters, a control parameter for a slip controller can advantageously be determined alternatively or additionally. This control parameter regulates the braking force acting on the wheel during braking in such a way that the actual wheel slip corresponds to a target slip determined using the friction characteristic curve. With this latter design variant, it is thus possible to determine optimal control parameters for the slip controllers during simulation runs based on the physical model. These parameters then allow the fulfillment of specified approval requirements in real-world operation, even under special test conditions, such as rails wetted with water-soap mixtures.

[0018] At least one parameter relevant to braking behavior can be determined, for example, by the vehicle's control unit.

[0019] Alternatively or additionally, at least one parameter relevant to braking behavior can advantageously be determined by a device, for example a computing device, outside the rail vehicle.

[0020] Advantageously, at least one braking behavior-relevant parameter can be used within the framework of a procedure for commissioning a braking system of the rail vehicle, whose braking system is to meet specified approval requirements, whereby the fulfillment of the approval requirements is simulated by including the at least one determined braking behavior-relevant parameter.

[0021] The invention further relates to a device for determining at least one braking-behavior-relevant parameter for controlling or regulating a braking system of a rail vehicle according to claim 10. According to the invention, with respect to such a device, it is provided that the physical model is configured to take into account the influence of fluid on a rail traversed by the wheel to be braked, by including a quantity of fluid acting on the wheel to be braked, wherein the quantity of fluid acting on the wheel to be braked is calculated taking into account a fluid reduction caused by the preceding wheel.

[0022] Regarding the advantages of the device according to the invention and its advantageous embodiments, reference is made to the above explanations in connection with the method according to the invention and its advantageous embodiments. Specifically, the device can perform all of the above process steps individually or in any combination.

[0023] It is advantageous if the device is designed to determine the frictional contact, which is one of the braking behavior-relevant parameters, in the form of a frictional contact characteristic curve based on a moisture value indicating the moisture on the rail to be traversed, and to determine a control parameter for a slip controller of the rail vehicle as a further braking behavior-relevant parameter based on the determined frictional contact characteristic curve, wherein the slip controller regulates the braking of the rail vehicle by regulating the slip on the basis of this further braking behavior-relevant parameter.

[0024] The invention also relates to a rail vehicle with a device as described above.

[0025] Regarding the advantages of the rail vehicle according to the invention and its advantageous embodiments, reference is made to the above statements in connection with the method according to the invention and its advantageous embodiments.

[0026] The invention is explained in more detail below with reference to exemplary embodiments; these show, by way of example, Figure 1: Auxiliary characteristic curves over slip for different environmental conditions; Figure 2: A physical model describing the influence of a leading wheel on a following wheel to be braked; Figure 3: An embodiment of an external device suitable for determining at least one braking behavior-relevant parameter for controlling or regulating at least one slip controller; and Figure 4: An embodiment of an internal vehicle device suitable for determining at least one braking behavior-relevant parameter for controlling or regulating at least one slip controller.

[0027] For the sake of clarity, the same reference symbols are always used in the figures for identical or comparable components.

[0028] The following is an example related to the Figure 1 and 2First, it is explained how, based on a first and second slip-dependent auxiliary characteristic curve HK1 and HK2 (see Figure 1 ) and a fluid value Fw, which represents the moisture on a rail 30 according to Figure 2 indicates that at least one braking-related parameter, the frictional contact Fx, can be determined for two or more wheels, taking into account the influence of the leading wheel (see reference numeral 10 in Figure 2 ) to the next wheel (see reference 20 in Figure 2 ) is taken into account. The frictional force Fx will fluctuate over time during a journey and thus forms a frictional force characteristic Fx(t) over time.

[0029] The two auxiliary characteristic curves HK1 and HK2 each describe the force transmission Fx as a function of the respective slip Cx, whereby the first auxiliary characteristic curve HK1 describes the force transmission Fx as a function of the slip Cx with a dry splint and the second auxiliary characteristic curve HK2 describes the force transmission Fx as a function of the slip Cx with a wet splint. Figure 1 shows, as an example, the course of the two auxiliary characteristic curves HK1 and HK2 over the slip Cx.

[0030] The friction characteristic Fx(t) of the friction Fx over time t is preferably calculated using the two auxiliary characteristic curves HK1 and HK2 as a function of the respective time-dependent fluid value Fw and the also time-dependent slip Cx(t) according to Fx t = Fw t ⋅ HK 1 Cx t + 1 − Fw t ⋅ HK 2 Cx t a) Calculation of the two auxiliary characteristic curves HK1 and HK2:

[0031] In a first step, an auxiliary function M1(t) is determined for the first auxiliary characteristic curve HK1 and an auxiliary function M2(t) is determined for the second auxiliary characteristic curve HK2 over time t according to M 1 t = M 01 ⋅ 1 − A 1 / exp − B 1 ⋅ V t + A 1 M 2 t = M 02 ⋅ 1 − A 2 / exp − B 2 ⋅ V t + A 2 where M01 denotes the maximum of a dimensionless friction coefficient, which can assume a value of, for example, M01 = 0.08 for the first auxiliary characteristic curve HK1. M02 denotes the maximum of a dimensionless friction coefficient for the second auxiliary characteristic curve HK2 and can assume a value of, for example, 0.35.

[0032] A1 and A2 denote the ratio between the minimum and maximum coefficients of friction for the respective first and second auxiliary characteristic curves HK1 and HK2. For the first auxiliary characteristic curve HK1, the ratio A can be on the order of 0.1, and for the second auxiliary characteristic curve HK2, on the order of 0.2.

[0033] B1 and B2 each represent a dimensionless factor in the exponential reduction of the frictional resistance drop with increasing slip values. For the first auxiliary characteristic curve HK1, the factor B1 can be on the order of 0.3, and for the second auxiliary characteristic curve HK2, on the order of 0.2.

[0034] V(t) denotes the translational speed of wheels 10 and 20 in the longitudinal direction of the vehicle over time t.

[0035] In a second step, a second auxiliary function E1(t,Q(t)) is determined for the first auxiliary characteristic curve HK1 and a second auxiliary function E2(t,Q(t)) is determined for the second auxiliary characteristic curve HK2 according to E 1 t , Q t = Pi ⋅ G ⋅ Ah ⋅ Bh ⋅ C _ 11 ⋅ Cx t / 4 ⋅ Q t ⋅ M 1 t E 2 t , Q t = Pi ⋅ G ⋅ Ah ⋅ Bh ⋅ C _ 11 ⋅ Cx t / 4 ⋅ Q t ⋅ M 2 t where Pi is the mathematical constant or Archimedes constant, G is a shear modulus of the wheel (e.g. in Pa), Ah and Bh are the semi-axes of the contact ellipses of the wheel on the rail (e.g. in meters), C_11 is the so-called Kalker slip coefficient in the longitudinal direction, Cx is the slip of the wheel and Q is the wheel contact force of the wheel on the rail (e.g. in Newtons).

[0036] Using M1(t) and M2(t) respectively, and E1(t,Q(t)) and E2(t,Q(t)) respectively, the first and second auxiliary characteristic curves HK1 and HK2 can then be calculated according to HK 1 = M 1 t ⋅ Ka ⋅ E 1 t , Q t / 1 + E 1 t , Q t 2 + atan Ks ⋅ E 1 t , Q t / Pi HK 2 = M 2 t ⋅ Ka ⋅ E 2 t , Q t / 1 + E 2 t , Q t 2 + atan Ks ⋅ E 2 t , Q t / Pi

[0037] Ka denotes dimensionless reduction factors in the adhesion area of ​​the wheel / rail contact area and Ks denotes dimensionless reduction factors in the sliding area of ​​the wheel / rail contact area. b) Calculation of the liquid value Fw: (1) Front wheel 10 (see Figure 2):

[0038] The fluid value Fw, which is used to link the two auxiliary curves HK1 and HK2 for the purpose of forming the friction characteristic curve Fx(t), is preferably calculated for the i-th wheel 10, which is front in the direction of travel on a rail 30, according to Fwi t = 1 / 1 + exp − Kb ⋅ Swi t − dt + Sai t / Smax t − 0.5

[0039] Sai refers to the amount of liquid added in front of the front wheel 10, for example, sprayed onto the rail in front of the front wheel 30 for a test run. Sa can be calculated as follows: Sai t = Kad ⋅ 1 / V t ⋅ Bh ⋅ dV _ liquid / dt where Kad is a dimensionless parameter, Bh is the half-axis length of the contact ellipse in the direction of travel, V(t) is the translational speed of the wheel in the longitudinal direction of the vehicle, and dV_liquid / dt is the liquid rate in the case of liquid addition.

[0040] Smax refers to the maximum amount of fluid under the wheel 30 and can be determined according to Smax t = min Kmax / V t , K _ lim where Kmax and K_lim denote dimensionless parameters.

[0041] Swi denotes the amount of fluid under the i-th wheel 30 and can be calculated according to: Swi t = min Swi t − dt + Sai t , Smax t − Sworn t ⋅ K _ distr where Swi(t-dt) denotes the amount of fluid under the i-th wheel 30 that was present at time t-dt (dt: duration of one wheel revolution) and is at least partially returned to the wheel contact surface after the next wheel revolution.

[0042] Sworn denotes the amount of liquid consumed through evaporation or similar processes, i.e., the amount of liquid lost. K_distr denotes a dimensionless parameter.

[0043] Sworn can be calculated according to: Sworn t = Kworn ⋅ Wfriction t where Kworn is a dimensionless parameter and Wfriction specifies the frictional work of the wheel, for example in Nm (Newton Meter).

[0044] For the i-th wheel 10, the friction characteristic Fxi(t) is thus given by: Fxi t = Fwi t ⋅ HK 1 t + 1 − Fwi t ⋅ HK 2 t (2) Following wheel 20:

[0045] For the (i+1)th wheel 20 following the i-th wheel 10, the fluid value Fwi+1, which is used to link the two auxiliary curves HK1 and HK2, is preferably calculated according to Fwi + 1 t = 1 / 1 + exp − Kb ⋅ Swi + 1 t − dt + Sai + 1 t / Smax t − 0.5

[0046] Swi+1(t) is calculated for the following wheel 20 in the same way as Swi(t), i.e. in the same way as has been explained above for the i-th wheel 10.

[0047] Assuming that no additional amount of liquid is added externally to the (i+1)-th wheel 20, Sai+1 results solely from the amount of liquid left behind by the i-th wheel 10 on the rail 30; in this case, therefore, the following applies: Sai + 1 t = Souti t where Souti describes the amount of fluid left behind by the i-th wheel 10 and can be calculated, for example, according to Souti t = Kdistr ⋅ Sai t + Srail t

[0048] With Srail(t) = Swi(t)·(1 / Kdistr-1) then: Sai + 1 t = Souti t = Kdistr ⋅ Sai t + Swi t ⋅ 1 / Kdistr − 1

[0049] For subsequent wheels without an external fluid supply, i.e., for the (i+2)th wheel, etc., a corresponding calculation would be applied as for the (i+1)th wheel, provided that Sai is always derived from the amount of fluid left behind by the preceding wheel. For the (i+2)th wheel, for example, this would result in... Sai + 2 t = Souti + 1 t

[0050] The friction characteristic Fxi+1(t) for the following (i+1)th wheel 20 is then calculated according to: Fxi + 1 t = Fwi + 1 t ⋅ HK 1 t + 1 − Fwi + 1 t ⋅ HK 2 t

[0051] In summary, the above takes into account the following in connection with the Figure 1 and 2The described physical model for determining the force transmission states that a leading i-th wheel 10 influences the amount of fluid acting on the following (i+1)-th wheel 20, because a portion of the amount of fluid relevant for the leading i-th wheel (cf. portion Kdistr·Swi(t) in the formulas above) remains on the leading i-th wheel and continues to rotate with it, and another portion Sworn(t) is lost due to the friction work of the i-th wheel.

[0052] The above in connection with the Figure 1 and 2 The described physical model can, for example, be implemented by an institution 100 (see Figure 3 ) can be used.

[0053] The facility 100 according to Figure 3It comprises a computing unit 110 and a memory 120 in which a software module SPM is stored. When executed by the computing unit 110, the software program module SPM determines the operation of the unit 100, or at least it influences its operation.

[0054] When the software module SPM is executed by the computing unit 110, the unit 100 preferably first executes a method based on the above-described and in the Figure 3 Using the physical model designated PHYSM for wheels 10 and 20 of a rail vehicle 200, the friction characteristics Fxi(t) and Fxi+1(t) are first calculated. The friction characteristics Fxi(t) and Fxi+1(t) each describe the friction Fx as the primary braking behavior-relevant parameters over time.

[0055] If the friction characteristics Fxi(t) and Fxi+1(t) are available, a journey of the rail vehicle 200 on a given track 300 can be simulated over time. Based on the simulation results of such simulated journeys, suitable control parameters BRPi and BRPi+1, for example, can be calculated as further (secondary) braking behavior-relevant parameters for controlling or regulating slip controllers 211i and 211i+1 of a braking system 210 of the rail vehicle 200.

[0056] The slip controllers 211i and 211i+1 are used in the embodiment according to Figure 3 actuated by a brake control unit 213 of the brake system 210 by means of a brake signal BS.

[0057] In the simulation of the journey(s) of rail vehicle 200 on track 300 and in the determination of the further braking behavior-relevant parameters BRPi and BRPi+1, the physical model PHYSM is again used, at least indirectly, due to the use of the friction characteristics Fxi(t) and Fxi+1(t), as described above in connection with the Figure 1 and 2 has been described because, in the driving simulation, the frictional contact Fx between the wheels 10 and 20 and the rail 30 is taken into account.

[0058] Using the physical model PHYSM, a journey can be simulated, for example, incorporating virtually added quantities of liquid, which are injected, for instance, in the direction of travel P in front of the i-th (e.g., i=1) wheel 10. Within the framework of the simulation(s), suitable or even optimal numerical values ​​for the parameters BRPi and BRPi+1 can then be advantageously determined. These values ​​can be used in real (later) operation as control parameters in the slip controllers 211i and 211i+1 for the braking operation of the rail vehicle 200.

[0059] During the Figure 3In the illustrated embodiment, the device 100 is preferably an external device that tests, prior to the initial commissioning of a real rail vehicle or at least prior to a real test run of the rail vehicle 200, whether the rail vehicle 200 would meet specified approval requirements. For this purpose, it first calculates the braking behavior-relevant parameter(s) and then simulates test runs of the rail vehicle 200 based on these calculations. Within the framework of the simulations and tests, it determines, for example by computational trial and error, suitable braking behavior-relevant control parameters for the braking system 210, such as the parameters BRPi and BRPi+1 for the slip controllers 211i and 211i+1, with which the approval requirements are met. Subsequently, the braking behavior-relevant control parameters determined by the simulation are implemented in the real rail vehicle.Real test runs can be carried out with the actual rail vehicle after this implementation.

[0060] The Figure 4 shows an alternative design variant, in which the in Figure 3 The device 100 shown is an internal device of the rail vehicle 200 and is formed, for example, by a vehicle control unit of the rail vehicle 200 or integrated into a vehicle control unit not shown. The internal device 100 can simulate and define the braking behavior-relevant parameter(s) before or during travel, for example, also taking into account other current travel parameters such as temperature or rain. The braking behavior-relevant parameters can again be control parameters for the slip controllers 211i or 211i+1, which act on the respective assigned brake 212i or 212i+1 of the rail vehicle 200 and regulate the braking force of the assigned brake.

[0061] This in connection with the Figure 1 and 2 The described physical friction model advantageously makes it possible to simulate the friction conditions of the wheels even on a water / soap mixture or a rail wetted with a water / soap mixture. As described, the conditioning effect caused by preceding wheels can be taken into account, which can lead to an increase in friction and correspondingly changed slip values ​​for following wheels, because preceding wheels alter or reduce the quantity of the water / soap mixture.

[0062] This in connection with the Figure 1 and 2 The described physical model enables, for example, the simulation of anti-slip test drives according to the EN15595 standard. This allows for a significant reduction in complex and expensive vehicle tests during initial commissioning or acceptance tests.

[0063] Although the invention has been illustrated and described in detail by means of preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived by the person skilled in the art without leaving the scope of protection of the invention as defined by the following claims.

Claims

1. Method for determining at least one braking-behaviour-relevant parameter for the control or regulation of a braking system (210) of a rail vehicle (200), wherein a physical model (PHYSM) is used in the determining of the at least one braking-behaviour-relevant parameter, the physical model taking into account the influence of a wheel (10) leading a wheel (20) to be braked, specifically with respect to an influence effect which the leading wheel (10) has on the adhesion between the trailing wheel (20) to be braked and the rail (30), characterised in that - the physical model (PHYSM) takes into account the influence of liquid on a rail (30) travelled by the wheel (20) to be braked, namely by taking into account a quantity of liquid acting on the wheel (20) to be braked, - wherein the quantity of liquid acting on the wheel (20) to be braked is calculated by taking into account a liquid reduction caused by the leading wheel (10).

2. Method according to claim 1, characterised in that - on the basis of the physical model (PHYSM), a first auxiliary characteristic (HK1), which describes an adhesion as a function of slippage when the rail (30) is dry, and a second auxiliary characteristic (HK2), which describes the adhesion as a function of slippage when the rail (30) is wet, are calculated for the rail vehicle (200) and - taking into account the first and second auxiliary characteristic (HK1, HK2) and a moisture value indicating the amount of liquid on the rail (30) during braking, an adhesion characteristic lying between the first and second auxiliary characteristic (HK1) is determined, which represents the actual adhesion, which forms the or at least one of the braking-behaviour-relevant parameters to be determined, over time.

3. Method according to claim 2, characterised in that the adhesion characteristic is determined according to Fx t = Fw t · HK 1 Cx t + 1 − Fw t · HK 2 Cx t where HK1 describes the first auxiliary characteristic as a function of the time t-dependent slippage Cx, HK2 the second auxiliary characteristic as a function of the time-dependent slippage Cx(t) and Fw the moisture value.

4. Method according to one of the preceding claims 2-3, characterised in that the first auxiliary characteristic HK1 is determined according to HK 1 = M 1 t ⋅ Ka ⋅ E 1 t , Q t / 1 + E 1 t , Q t 2 + atan Ks ⋅ E 1 t , Q t / Pi where Ka describes a dimensionless reduction factor in the adhesion region of the wheel / rail contact area, Ks a dimensionless reduction factor in the slippage region of the wheel / rail contact area, Q the wheel contact force of the wheel (20) to be braked on a rail (30), M1(t) a first auxiliary function of the first auxiliary characteristic (HK1) and E1(t) a second auxiliary function of the first auxiliary characteristic (HK1).

5. Method according to one of the preceding claims 2-4, characterised in that the second auxiliary characteristic (HK2) is determined according to HK 2 = M 2 t ⋅ Ka ⋅ E 2 t , Q t / 1 + E 2 t , Q t 2 + atan Ks ⋅ E 2 t , Q t / Pi where Ka describes a dimensionless reduction factor in the adhesion region of the wheel / rail contact area, Ks a dimensionless reduction factor in the slippage region of the wheel / rail contact area, Q the wheel contact force of the wheel (20) to be braked on a rail (30), M2(t) a first auxiliary function of the second auxiliary characteristic (HK2) and E2(t) a second auxiliary function of the second auxiliary characteristic (HK2).

6. Method according to one of the preceding claims, characterised in that the adhesion between the wheel (20) to be braked and a railroad track (30) is determined as the braking-behaviour-relevant parameter or at least one of the braking-behaviour-relevant parameters.

7. Method according to one of the preceding claims, characterised in that as a braking-behaviour-relevant parameter or at least one of the braking-behaviour-relevant parameters, a control parameter for a slip controller (211i+1) is determined, which when braking the wheel (20) to be braked regulates the braking force acting on the wheel (20) in such a way that the actual slippage of the wheel corresponds to a target slippage determined using the adhesion characteristic.

8. Method according to one of the preceding claims, characterised in that the at least one braking-behaviour-relevant parameter is determined by a vehicle control device of the vehicle.

9. Method according to one of the preceding claims, characterised in that - the at least one braking-behaviour-relevant parameter is determined by a facility (100) outside the rail vehicle (200) and is used as part of a method for putting into service a braking system (210) of the rail vehicle (200) whose braking system is intended to meet specified approval requirements, - wherein the fulfilment of the approval requirements is simulated taking into account the at least one determined braking-behaviour-relevant parameter.

10. Facility (100) for determining at least one braking-behaviour-relevant parameter for controlling or regulating a braking system (210) of a rail vehicle (200), wherein the facility (100) is designed to use a physical model (PHYSM) when determining the parameter, the physical model taking into account the influence of a wheel (10) which leads a wheel (20) to be braked, specifically with respect to an influence effect which the leading wheel (10) has on the adhesion between the trailing wheel (20) to be braked and the rail (30), characterised in that - the physical model (PHYSM) is configured to take into account the influence of liquid on a rail (30) travelled by the wheel (20) to be braked, namely by taking into account a quantity of liquid acting on the wheel (20) to be braked, - wherein the quantity of liquid acting on the wheel (20) to be braked is calculated taking into account a liquid reduction caused by the leading wheel (10).

11. Facility (100) according to claim 10, characterised in that - the facility (100) is designed to determine the adhesion, which forms one of the braking-behaviour-relevant parameters, in the form of an adhesion characteristic on the basis of a moisture value indicating the moisture on the rail (30) to be travelled on, and to determine a control parameter for a slip controller (211i, 211i+1) of the rail vehicle (200) on the basis of the determined adhesion characteristic as a further braking-behaviour-relevant parameter, - wherein the slip controller (211i, 211i+1) regulates the braking of the rail vehicle (200) on the basis of this further braking-behaviour-related parameter by regulating the slippage.

12. Rail vehicle (200) having a facility (100) according to claim 10 or 11.

13. Rail vehicle (200) according to claim 12, characterised in that - the facility (100) is designed to determine the adhesion, which forms one of the braking-behaviour-relevant parameters, in the form of an adhesion characteristic on the basis of a moisture value indicating the moisture on the rail (30) to be travelled on, and to determine a control parameter for a slip controller (211i, 211i+1) of the rail vehicle (200) on the basis of the determined adhesion characteristic as a further braking-behaviour-relevant parameter, - wherein the slip controller (211i, 211i+1) regulates the braking of the rail vehicle (200) on the basis of this further braking-behaviour-related parameter by regulating the slippage.

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