Data communication system, computer-implemented method for railway network data communication, computer program and non-volatile data carrier

Abstract

The invention discloses a rail vehicle (100). It obtains a basic parameter ([mu]) reflecting an initial value of a friction coefficient ([mu] e) associated with a rail section (310) in a railway network (300) and verifies the basic parameter ([mu]) by a process involving applying a gradually increasing braking force (BF) to a specific one of the axles to which the wheels (151, 152, 153, 154) of the rail vehicle (100) are connected measuring respective rotational speeds ([omega] 1, [omega] 2, [omega] 3, [omega] 4) of the axle; determining an absolute difference between the rotational speed (0) 2) of the particular one of the axles and an average rotational speed of the axles other than the particular one of the axles when the gradually increasing braking force (BF) is applied; and in response to the absolute difference exceeding a threshold, deriving a parameter (pm) reflecting a measured value of the friction coefficient ([mu] e), checking whether the measured value of the friction coefficient ([mu] e) is within an acceptance interval starting from the basic parameter ([mu]), and if so, determining that the absolute difference is within the acceptance interval. If so, the verification value of the friction coefficient is designated to be equal to the measured value of the friction coefficient ([mu] e). A friction data message (M ([mu] e)) containing the verification value of the friction coefficient is then issued.

Description

Technical Field

[0001] The invention relates generally to a safety arrangement for a rail vehicle braking system. In particular, the invention relates to a data communication system for a railway network according to the preamble of claim 1 and to a corresponding computer-implemented method. The invention also relates to a computer program and a non-volatile data carrier storing such a computer program. Background Art

[0002] When an electric rail vehicle is in operation, the on-board electric motor is usually used as a generator for decelerating the rail vehicle. However, for efficiency and safety reasons, this braking strategy cannot be relied upon exclusively. In particular, a dedicated braking function is always required to ensure emergency braking functionality and to ensure that the rail vehicle remains stationary after it has stopped. In many cases, the same brake unit is used for different types of braking functionality, such as service brake, emergency brake and parking brake.

[0003] In order to achieve efficient slowing of rail vehicles, it is crucial to have an accurate knowledge of the expected braking distance. The expected braking distance in turn depends to a large extent on the adhesion conditions at the wheel-rail interface, ie the applicable dynamic friction coefficient.

[0004] Today, there are systems for informing rail vehicles of various characteristics of different track sections in a railway network so that the rail vehicles can adjust their driving behavior accordingly.

[0005] For example, US2007 / 0219682 shows a system for providing at least one of train information and rail characterization information used in train performance, the system comprising a first element for determining the position of a train on a rail segment and / or a time from the start of a trip. Also included is a rail characterization element for providing rail segment information and a sensor for measuring the operating condition of at least one locomotive in the train. A database for storing the rail segment information and / or the operating condition of at least one of the locomotives is provided. Also included is a processor to correlate information from the first element, the rail characterization element, the sensor, and / or the database so that the database can be used to create a trip plan that optimizes the train performance according to one or more operating criteria of the train.

[0006] WO 2022 / 006614 describes a method for improving the braking performance of a rail vehicle, the method comprising the following steps: a) associating one or more sensors with one or more components of the rail vehicle, at least one of the one or more sensors including an acoustic sensor configured to detect acoustic signals emitted from a wheel-rail interface; b) using the one or more sensors to obtain measured values ​​of one or more operating parameters of the rail vehicle; c) transmitting the measured values ​​of the one or more operating parameters to an operating parameter monitoring device; d) using a computing circuit of the operating parameter monitoring device to convert the measured values ​​into an output signal message, the output signal message including information related to one or more components of the rail vehicle and / or the adhesion condition at the wheel-rail interface; and e) electronically transmitting the output signal message to one or more receivers.

[0007] US2010 / 0023190 discloses a system for controlling a railway train on a rail section. The system includes a first element for determining the position of the train on the rail section; a second element for providing rail characterization information for the rail section; the rail characterization information related to the physical condition of the rail section; and a processor for controlling the applied traction and braking force of the train in response to the position of the train and the rail characterization information to reduce at least one of wheel wear and / or rail wear during the operation of the train on the rail section.

[0008] Although the above-mentioned systems can provide information dissemination that is potentially relevant to determining the expected braking distance, these systems generally provide data of unsatisfactory quality. As a result, it is not possible to determine a reliable estimate of the braking distance. As a result, unnecessarily large safety margins must be applied between rail vehicles, which results in a less than optimal throughput of the railway network. Summary of the invention

[0009] The object of the present invention is to address the above mentioned problems and to provide a solution which enables rail vehicles to obtain up-to-date high quality information about the applicable adhesion conditions at the wheel-rail interface in various parts of the railway network.

[0010] According to one aspect of the invention, the object is achieved by a data communication system for a railway network, the system comprising at least one measurement controller, at least one transmitter device and a set of receiver devices. The at least one measurement controller is configured to be included in a respective one of at least one rail vehicle of a data provider type. The at least one measurement controller is configured to obtain basic parameters reflecting initial values ​​of friction coefficients associated with a track segment, for example, via an incoming message or as default values. The at least one measurement controller is also configured to generate verification values ​​of the basic parameters, which verification values ​​reflect an updated friction coefficient between a track of the track segment and a wheel of the respective one of the at least one rail vehicle of the data provider type. The verification value is then generated by a process involving: measuring the individual rotational speeds of a particular one of the axles to which the wheels of at least one first rail vehicle are connected while applying a gradually increasing braking force to the axle; determining an absolute difference between the rotational speed of the particular one of the axles and an average rotational speed of the axles other than the particular one of the axles while applying the gradually increasing braking force; and responsive to the absolute difference exceeding a threshold, deriving a parameter reflecting a measured value of a coefficient of friction, checking whether the measured value of the coefficient of friction is within an acceptance interval from a base parameter, and if so, assigning a verification value equal to the measured value of the coefficient of friction. At least one transmitter device is configured to be included in a respective one of the at least one rail vehicle of the data provider type and to send out a friction data message containing the verification value of the coefficient of friction. Each receiver device in the set of receiver devices is configured to be included in a respective one of the at least one rail vehicle in the railway network and to receive the friction data message.

[0011] The above described data communication system is advantageous because it allows sharing of verified friction measurements, i.e. information that rail vehicles carrying receiver devices can rely on when, for example, determining the appropriate distance to a preceding rail vehicle. This in turn enables an increase in overall throughput in the rail network.

[0012] According to one embodiment of this aspect of the invention, each receiver device in the set of receiver devices is configured to receive a friction data message via a wireless interface, and each of the at least one transmitter device is configured to send out a friction data message via the wireless interface. Thus, for example, friction data can be efficiently exchanged between rail vehicles during travel in a railway network.

[0013] According to another embodiment of this aspect of the invention, each of the at least one measurement controller is configured to generate a friction data message, the friction data message comprising: a verified value of the friction coefficient, an identification of a track segment to which the verified value of the friction coefficient relates, and a point in time when the verified value of the friction coefficient was derived. Thus, any rail vehicle carrying a receiver device can conveniently determine the relevant track segment to which the friction coefficient relates and the reliability of the received information.

[0014] According to a further embodiment of this aspect of the invention, each receiver device in the set of receiver devices is configured to receive at least two friction data messages relating to the track segment and to derive an updated value of the friction coefficient for the track segment based on the at least two received friction data messages. Here, the updated value of the friction coefficient is based on a balance of the verified values ​​of the friction coefficient included in the at least two friction data messages.

[0015] For example, balancing of the verification value of the friction coefficient may involve comparing the verification value of the friction coefficient of each of the at least two received friction data messages with a threshold level of the friction coefficient, and assigning an updated value of the friction coefficient equal to the verification value of the friction coefficient of the most recently received message of the at least two received friction data messages if the verification value of the friction coefficient of the most recently received message is lower than or equal to the threshold level. However, if the most recently received message indicates a friction coefficient that is higher than the threshold level, the updated value of the friction coefficient is assigned to be equal to the friction coefficient of the threshold level. Thus, it can be ensured that an excessively high value is not assigned to the friction coefficient.

[0016] Alternatively, balancing of the validation value of the coefficient of friction may involve assigning the updated value of the coefficient of friction equal to the validation value of the coefficient of friction of the most recently received message of at least two received friction data messages without regard to any threshold level. Thus, maximum advantage of the validation value of the coefficient of friction may be taken.

[0017] According to yet another embodiment of this aspect of the invention, the system further comprises at least one dispatching node configured to: receive a friction data message from one of the at least one transmitter device via a wireless interface, and to deliver the received friction data message to at least one of the receiver devices in the set of receiver devices via the wireless interface. Such a communication infrastructure in the form of a dispatching node is beneficial because it bridges the distance gap between different rail vehicles and thus ensures that the friction data messages are properly distributed to the intended receiver devices.

[0018] Preferably, at least one scheduling node is configured to: receive at least two friction data messages associated with a particular track segment, derive an updated value of the friction coefficient value for the track segment based on the at least two received friction data messages, and communicate the updated value of the friction coefficient for the track segment to at least one of the receiver devices. Similar to the above, the updated value of the friction coefficient is based on a balance of the verified values ​​of the friction coefficient included in the at least two friction data messages. Thus, the friction data may be aggregated and enhanced at the at least one scheduling node before being distributed to rail vehicles in the railway network.

[0019] Further similar to the above, balancing of the verification value of the friction coefficient may involve assigning an updated value of the friction coefficient equal to the verification value of the friction coefficient of the most recently received message of the at least two received friction data messages. Alternatively, the verification value of the friction coefficient of each of the at least two received friction data messages may be compared to a threshold level of the friction coefficient, and only if the most recently received message contains a verification value of the friction coefficient below or equal to the threshold level, assigning the updated value of the friction coefficient equal to the verification value of the friction coefficient of the most recently received message. Otherwise, assigning the updated value of the friction coefficient equal to the friction coefficient of the threshold level. This is advantageous for the same reasons as above.

[0020] According to another aspect of the invention, the object is achieved by a computer-implemented method for data communication in a railway network, the method being implemented in at least one processing circuit and involving: obtaining a basic parameter reflecting an initial value of a coefficient of friction associated with a track segment in the railway network in a measurement controller included in a rail vehicle of a data provider type, and generating a verification value of the basic parameter in the measurement controller. The verification value reflects an updated coefficient of friction between the track of the track segment and the wheels of a corresponding one of at least one rail vehicle of the data provider type. The verification value is generated by a process involving: measuring individual rotational speeds of a specific one of the axles to which the wheels of at least one first rail vehicle are connected while applying a gradually increasing braking force to the axle; determining an absolute difference between the rotational speed of the specific one of the axles and an average rotational speed of the axles other than the specific one of the axles when applying the gradually increasing braking force; and responsive to the absolute difference exceeding a threshold, deriving a parameter reflecting a measured value of the coefficient of friction, checking whether the measured value of the coefficient of friction is within an acceptance interval from the basic parameter, and if so, assigning the verification value equal to the measured value of the coefficient of friction. Furthermore, a friction data message is sent from a transmitter device included in a rail vehicle of data supplier type, the friction data message containing a verified value of the friction coefficient. In addition, the method involves receiving the friction data message in a receiver device included in a rail vehicle in a railway network. The advantages of the method as well as its preferred embodiments will become apparent from the discussion above with reference to the proposed friction testing system.

[0021] According to a further aspect of the invention, the object is achieved by a computer program loadable into a non-volatile data carrier communicatively connected to a processing unit. The computer program comprises software for performing the above method when the program is run on the processing unit.

[0022] According to another aspect of the invention, the object is achieved by a non-volatile data carrier comprising the above-mentioned computer program.

[0023] Further advantages, advantageous features and applications of the invention will become apparent from the following description and the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will now be explained in more detail by means of preferred embodiments disclosed as examples and with reference to the accompanying drawings.

[0025] Figure 1 schematically illustrates a rail vehicle comprising an apparatus forming part of a data communications system according to one embodiment of the invention;

[0026] Figure 2 shows a graph illustrating an example of coefficient of friction as a function of wheel slip;

[0027] Figure 3 shows a schematic railway network in which a data communication system according to one embodiment of the present invention is implemented;

[0028] Figure 4 A block diagram of a measurement controller according to an embodiment of the present invention is shown; and

[0029] Figure 5 A preferred exemplary embodiment of the method according to the invention is shown with the aid of a flow chart. DETAILED DESCRIPTION

[0030] exist Figure 1 In the drawing, a schematic diagram of a rail vehicle 100 can be seen comprising apparatus forming part of a data communication system according to one embodiment of the invention. Figure 3 A schematic railway network 300 is shown in which the proposed data communication system may be implemented.

[0031] The data communication system includes a set of receiver devices. Figure 1 An example of such a receiver device 110 is shown, which is comprised in a rail vehicle 100 and which is configured to receive a friction data message M(μ) from at least one other rail vehicle in the railway network 300. The friction data message M(μ) is related to a specific track section of the railway network 300, e.g. Figure 3 As shown in 310.

[0032] The data communication system also includes at least one measurement controller. Figure 1 An example of such a measurement controller 130 is shown comprised in a rail vehicle 100. Thus, by definition, the rail vehicle 100 is a rail vehicle of the data supplier type, ie a source for generating verified friction information, as will be described below.

[0033] The measurement controller 130 is configured to obtain a value reflecting the friction coefficient μ associated with the track segment 310. e The basic parameter μ may be received in the receiver device 110 by means of a friction data message M(μ) from another rail vehicle in the railway network 300, for example. The receiver device 110 may then forward the basic parameter μ to the measurement controller 130. Alternatively or additionally, the measurement controller 130 may generate the basic parameter μ, for example based on default assumptions or historical entries stored in the rail vehicle 100. Thus, the basic parameter μ may originate from another rail vehicle in the railway network 300, from a dedicated friction testing device measuring the track section 310, or from the rail vehicle 100 itself, for example by inference based on neighboring measurement points.

[0034] However, the measurement controller 130 is configured to generate a validation value of the basic parameter μ. The validation value reflects the updated friction coefficient μ between the rail 140 of the track section 310 and the wheels 151, 152, 153 and 154 of the rail vehicle 100 of the data provider type. e The validation value is produced through a process involving the following steps.

[0035] First, when gradually increasing braking force BF is applied to a specific axle (such as 152) among the axles to which wheels 151, 152, 153 and 154 of the rail vehicle 100 are respectively connected, the respective rotational speeds ω1, ω2, ω3 and ω4 of the corresponding axle are measured.

[0036] Then, when gradually increasing braking force BF is applied to the specific one of the axles, the absolute difference between the rotation speed ω2 of the specific one of the axles and the average rotation speed of the other axles (i.e., all axles except the specific one of the axles) is determined. In response to the absolute difference exceeding a threshold value, a value reflecting the friction coefficient μ e The measured value of the parameter μ m .

[0037] The measurement controller 130 is also configured to check the friction coefficient μ e Is the measured value of within the acceptance interval starting from the basic parameter μ, for example, starting from the friction coefficient μ e If the friction coefficient μ e If the measured value of is within the acceptance interval, the measurement controller 130 is configured to assign the verification value equal to the friction coefficient μ e Of course, the acceptance interval does not have to be ±10%. On the contrary, any wider or narrower extension of this interval is also conceivable.

[0038] However, if the friction coefficient μ e If the measured value is not within the acceptance interval, the measurement controller 130 is preferably configured to repeat the above steps to obtain the friction coefficient μ e The new measurement value.

[0039] Reference now Figure 2 , it will be explained how the friction coefficient μ can be derived by studying the absolute difference between the rotational speed ω2 of a particular one of the axles and the average rotational speeds ω1, ω3 and ω4 of the other axles when gradually increasing braking forces are applied to the particular one of the axles. e The verification value. Figure 2 The dynamic friction coefficient μ is shown kAn example of how this can be expressed as a function of the wheel slip s, which is understood here as a general term indicating the sliding or rotational movement of the wheel relative to the track. In other words, the wheel slip s applies to slowing down as well as to accelerating.

[0040] Typically, the dynamic friction coefficient μ k As the wheel slip s increases, it increases relatively proportionally. However, when approaching the peak μ e When the dynamic friction coefficient μ k Slightly stabilized. Friction coefficient peak μ e With optimal wheel slip e After this, a further increase in the wheel slip s leads to a dynamic friction coefficient μ k Gradually decrease.

[0041] According to the invention, a parameter μ that reflects the coefficient of friction between the wheels of the rail vehicle 100 and the rail on which the rail vehicle 100 travels is determined. m Ideally, the peak value μ should be e For example, the peak value μ can be obtained as follows e When the first wheel speed signal ω2 and the second wheel speed signal ω a The absolute difference between ω2 and ω a When the threshold is exceeded, this corresponds to at least one wheel 152 on a specific one of the axles being at an optimum wheel slip s e Wheel slip experienced near m The dynamic friction coefficient μ k It is given by the following expression:

[0042]

[0043] Where F is the force applied by the brake unit,

[0044] m is the mass of the rail vehicle 100, and

[0045] g is the standard acceleration due to gravity.

[0046] Assuming wheel slip s m is at optimum wheel slip e In the case of near k The peak value μ e .

[0047] In addition to the above, the data communication system according to the present invention comprises at least one transmitter device, Figure 1 In the embodiment of the present invention, the at least one transmitter device is exemplified by a unit 120 included in a rail vehicle 100 of the data provider type. The transmitter device is configured to emit a signal containing the friction coefficient μ eThe verification value of the friction data message M(μ e ), so that at least one other rail vehicle in the railway network 300 can receive the friction data message M(μ e ) to obtain information about the verification value.

[0048] Thus, each of at least one rail vehicle 100, 312, 313 and 314 equipped with a receiver device 110 in the railway network 300 can utilize the friction coefficient μ when maintaining a certain distance from the rail vehicle in front and / or when braking. e The verification value.

[0049] Preferably, the measurement controller 130 is configured to generate a friction data message M(μ e ), so that it not only contains the friction coefficient μ e The verification value of the friction coefficient μ e The verified value of the friction coefficient μ is obtained by identifying the track section to which it relates and specifying e The timestamp of the time when the value was verified. Figure 3 By showing the friction data message M(μ e ,ID 310 , t1) to illustrate this point, the friction data message includes the friction coefficient μ e The verification value and the identification ID of the track segment 310 associated with it 310 , and the friction coefficient μ e The time point t1 when the verification value is obtained.

[0050] Preferably, each receiver device 110 is configured to receive data via a friction data message M(μ e ) to receive the friction coefficient μ e The verification value of , and each transmitter device 120 is configured to transmit the verification value of , via a friction data message M(μ e ) to generate the friction coefficient μ e That is, this allows high-quality friction information to be conveniently shared between different rail vehicles 100, 312, 313 and 314 in the railway network 300.

[0051] In order to maintain an accurate and updated record of the adhesion conditions at the wheel-rail interface in the railway network 300, according to one embodiment of the present invention, each receiver device 110 is configured to receive at least two friction data messages M (μ) associated with the same track segment (such as 310). e ), and based on at least two received friction data messages M(μ e) to obtain an updated value of the friction coefficient of the track segment 310. The updated value of the friction coefficient is based on at least two friction data messages M (μ e ) includes the friction coefficient μ e However, technically, the balancing may involve a e The validation values ​​are not weighted in any way, such as by calculating an average or median.

[0052] According to one embodiment of the present invention, the friction coefficient μ e The balancing of the verification value involves combining at least two received friction data messages M(μ e ) for each of the friction coefficients μ e The verification value of is compared with the threshold level of the friction coefficient. If the friction coefficient μ of the latest received message e If the verification value of is lower than or equal to the threshold level, the updated value of the friction coefficient is assigned to be equal to at least two received friction data messages M(μ e ) is the friction coefficient value μ of the latest received message e Otherwise, the updated value of the friction factor is assigned a friction factor equal to the threshold level. Thus, the friction factor will never be assigned a better / higher value than the threshold level. This helps comply with regulatory requirements that may specify a maximum value for the friction factor.

[0053] Alternatively, according to another embodiment of the present invention, the friction coefficient μ e The balancing of the verification value involves specifying the updated value of the friction coefficient to be equal to at least two received friction data messages M(μ e ) is the friction coefficient μ of the latest received message e , i.e., without considering any maximum value of the friction coefficient.

[0054] Reference again Figure 3 According to one embodiment of the present invention, the data communication system comprises at least one scheduling node 320. Each scheduling node 320 is configured to receive a friction data message M (μ) from at least one transmitter device 120 via a wireless interface. e ,ID 310 , t1). Here, the rail vehicle 100 includes sending a friction data message M(μ e ,ID 310 ,t1). In addition, each scheduling node 320 is configured to transmit the received friction data message M to at least one of the receiver devices 110 in the group of receiver devices via the wireless interface. Here, the corresponding receiver device in each of the rail vehicles 312, 313 and 314 receives the friction data message M (μ) from the scheduling node 320, respectively. e,ID 310 , t1). Therefore, it is sufficient that the rail vehicles 100, 312, 313 and 314 are communicatively connected to at least one dispatching node 320 in order to exchange friction information with other rail vehicles in the railway network 300.

[0055] According to one embodiment of the present invention, the scheduling node 320 is configured to receive at least two friction data messages M (μ) associated with a specific track segment (such as 310). e ,ID 310 , t1). The scheduling node 320 is further configured to receive the friction data message M(μ e ,ID 310 , t1) to obtain an updated value of the friction coefficient of the track segment 310. Similar to the above, the updated value of the friction coefficient is based on at least two friction data messages M (μ e ,ID 310 ,t1) includes the friction coefficient μ e The scheduling node 320 is configured to communicate the updated value of the coefficient of friction of the track segment 310 to at least one of the receiver devices 110 by sending out a friction data message M over the wireless interface.

[0056] Further similar to the above, according to one embodiment of the present invention, the friction coefficient μ e The balancing of the verification value involves combining at least two received friction data messages M(μ e ,ID 310 ,t1) of each of the friction coefficient μ e The verification value is compared with the threshold level of the friction coefficient. If at least two received friction data messages M(μ e ,ID 310 , the friction coefficient μ of the latest received message in t1) e If the verification value of is lower than or equal to the threshold level, the updated value of the friction coefficient is assigned to be equal to the friction coefficient μ of the most recently received message. e Otherwise, the scheduling node 320 is configured to assign an updated value of the friction coefficient to be equal to the threshold level of friction coefficient.

[0057] Alternatively, according to one embodiment of the present invention, the friction coefficient μ implemented by the scheduling node 320 is e The balancing of the verification value simply involves assigning the updated value of the friction coefficient equal to at least two received friction data messages M(μ e ,ID 310 , the friction coefficient μ of the latest received message in t1) e The verification value.

[0058] Figure 4 A block diagram of a measurement controller 130 according to one embodiment of the present invention is shown. The measurement controller 130 comprises a processing circuit in the form of at least one processor 430 and a storage unit 420 (i.e. a non-volatile data carrier) storing a computer program 425, which in turn contains software for causing the at least one processor 430 to perform the actions mentioned in the present disclosure when the computer program 425 is run on the at least one processor 430.

[0059] To summarize, and for reference Figure 5 Referring to the flowchart in FIG. 1 , a computer-implemented method for data communication in the railway network 300 performed by the measurement controller 130 according to a preferred embodiment of the present invention will now be described.

[0060] In a first step 510 , it is checked whether a basic parameter μ has been obtained, which reflects the friction coefficient μ associated with a specific track section 310 in the railway network 300 . e If the basic parameter μ has been obtained, for example, via the received friction data message M(μ), steps 520 and 530 follow; otherwise, the process loops back and remains at step 510.

[0061] The validation value of the basic parameter μ is generated by executing steps 520 to 570. The validation value reflects the updated friction coefficient μ between the rail 140 of the track section 310 and the wheel of the rail vehicle 100 of the data provider type (ie, in which the process is performed). e .

[0062] In step 520 , the rotational speed of a specific one of the axles of the rail vehicle 100 of the data provider type is obtained, and in step 530 , preferably in parallel with step 520 , the average rotational speed of the axles other than the specific one of the axles is obtained.

[0063] In step 540 following step 520, a braking force BF is applied to the specific one of the axles, and in step 550 following steps 540 and 530, it is checked whether the absolute difference between the rotation speed of the specific one of the axles and the average rotation speed of the axles other than the specific one of the axles exceeds a threshold. If so, step 560 follows; otherwise, the process loops back to steps 520 and 530. Next time, when step 540 is reached, the braking force BF is applied with a slightly larger magnitude than the previous time, so that the braking force BF gradually increases for each pass through the cycle.

[0064] In step 560, a parameter μ is obtained that reflects the measured value of the friction coefficient μe. m As mentioned above Figure 2 The friction coefficient μ is obtained as described abovee The measured value.

[0065] Thereafter, step 570 checks whether the measured value of the friction coefficient μe is within the friction coefficient μe reflected by the basic parameter μ obtained in step 510. e If the measured value of the friction coefficient μe is found to be within the acceptance interval, the verified value of the basic parameter μ is assigned to be equal to the friction coefficient μe. e The measured value of , and the next step is step 580. Otherwise, the process loops back to steps 520 and 530 to obtain a new measured value of the friction coefficient μe.

[0066] In step 580, a message M(μ) containing the verification value of the basic parameter μ is sent, for example, via a wireless interface. e ), so that other rail vehicles in the railway network 300 can receive the message. After this, the process loops back to step 510.

[0067] refer to Figure 5 All process steps described and any subsequence of steps can be controlled by means of a programmed processor. In addition, although the embodiments of the present invention described above with reference to the accompanying drawings include a processor and a process executed in at least one processor, the present invention is therefore also extended to a computer program adapted to put the present invention into practice, in particular a computer program on or in a carrier. The program can be in the form of source code, object code, intermediate source code and object code (such as in a partially compiled form), or any other form suitable for implementing the process according to the present invention. The program can be part of an operating system, or it can be a separate application. The carrier can be any entity or device capable of carrying the program. For example, the carrier can include a storage medium such as a flash memory, a ROM (read-only memory), such as a DVD (digital video / versatile disk), a CD (optical disk) or a semiconductor ROM, an EPROM (erasable programmable read-only memory), an EEPROM (electrically erasable programmable read-only memory) or a magnetic recording medium, such as a floppy disk or a hard disk. In addition, the carrier can be a transmittable carrier, such as an electrical signal or optical signal that can be transmitted via a cable or optical cable or by radio or by other means. When the program is embodied in a signal that can be directly transmitted by a cable or other device or means, the carrier can be composed of such a cable or device or means. Alternatively, the carrier may be an integrated circuit in which the program is embedded, the integrated circuit being adapted for performing the relevant process or intended for performing the relevant process.

[0068] When used in this specification, the term "comprising" is used to specify the presence of the recorded features, integers, steps or components. The term does not exclude the presence or addition of one or more additional elements, features, integers, steps or components or combinations thereof. The indefinite article "a" or "an" does not exclude plurality. In the claims, the word "or" should not be interpreted as an exclusive or (sometimes referred to as "XOR"). On the contrary, unless otherwise indicated, expressions such as "A or B" cover all cases of "A and not B", "B and not A" and "A and B". The mere fact that certain measures are cited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting the scope.

[0069] It should also be noted that features from the various embodiments described herein may be combined freely, unless it is explicitly stated that such a combination is inappropriate.

[0070] Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0071] The invention is not limited to the embodiments described in the figures but may be varied freely within the scope of the claims.

Claims

1. A data communication system for a railway network (300), the system comprising: At least one measurement controller (130), the at least one measurement controller being configured to: included in a respective one of at least one rail vehicle (100) of the data provider type, Obtaining a coefficient of friction (μ) associated with a track segment (310) in the railway network (300) e ), and generating a verified value of the basic parameter (μ) reflecting an updated coefficient of friction (μ) between the rail (140) of the track section (310) and the wheels (151, 152, 153, 154) of the corresponding one of the at least one rail vehicle (100) of the data provider type; e ), and the verification value is generated by a process involving the following: measuring the respective rotational speeds (ω1, ω2, ω3, ω4) of a specific one of the axles to which the wheels (151, 152, 153, 154) of at least one first rail vehicle are connected while applying a gradually increasing braking force (BF) to the axle, determining an absolute difference between the rotational speed (ω2) of the particular one of the axles and an average rotational speed of the axles other than the particular one of the axles while applying the gradually increasing braking force (BF), and in response to the absolute difference exceeding a threshold: The friction coefficient (μ e ) of the measured value (μ m ); Check the friction coefficient (μ e ) is within the acceptance interval from the basic parameter (μ), and if so, then The verification value is assigned to be equal to the friction coefficient (μ e ), and At least one transmitter device (120), the at least one transmitter device being configured to: is comprised in a respective one of at least one rail vehicle (100) of the data provider type, and The friction coefficient (μ e ) of the verification value of the friction data message (M(μ e )); as well as A set of receiver devices (110), each of the set of receiver devices being configured to: at least one rail vehicle (100, 312, 313, 314) included in the railway network (300), and Receive the friction data message (M(μ e )).

2. The system of claim 1, wherein: Each receiver device (110) in the set of receiver devices is configured to receive the friction data message (M(μ)) via a wireless interface. e )),and Each of the at least one transmitter device (120) is configured to send out the friction data message (M(μ)) via the wireless interface. e )).

3. The system of claim 2, wherein each of the at least one measurement controller (130) is configured to generate the friction data message (M(μ e )、M(μ e ,ID 310 ,t1)) to include: The friction coefficient (μ e ), The friction coefficient (μ e ) of the track segment (310) associated with the verification value 310 ),as well as In deriving the friction coefficient (μ e ) is the time point (t1) when the verification value is obtained.

4. The system of claim 3, wherein each receiver device (110) in the set of receiver devices is configured to: Receiving at least two friction data messages (M(μ)) associated with the track segment (310) e )),as well as Based on at least two received friction data messages (M(μ e )) to derive an updated value of the friction coefficient of the track segment (310), the updated value of the friction coefficient being based on the data included in the at least two friction data messages (M(μ e )) in the friction coefficient (μ e )’s verification value.

5. The system of claim 4, wherein the friction coefficient (μ e ) includes: The at least two received friction data messages (M(μ e The friction coefficient (μ) of each of e ) is compared with a threshold level of the friction coefficient, and If the at least two received friction data messages (M(μ e The friction coefficient (μ) of the latest received message in e ) is lower than or equal to the threshold level, the updated value of the friction coefficient is assigned to be equal to the friction coefficient (μ) of the most recently received message e ), otherwise, The updated value of the coefficient of friction is assigned to be equal to the threshold level of coefficient of friction.

6. The system of claim 4, wherein the friction coefficient (μ e ) includes: The updated value of the friction coefficient is assigned to the at least two received friction data messages (M(μ e The friction coefficient (μ) of the latest received friction data message in e )’s verification value.

7. The system according to any one of claims 3 to 6, further comprising: at least one scheduling node (320), the at least one scheduling node being configured to: receive the friction data message (M(μ)) from one of the at least one transmitter device (120) via the wireless interface e ,ID 310 , t1)), and delivering the received friction data message (M) to at least one of the receiver devices (110) in the group of receiver devices via the wireless interface.

8. The system of claim 7, wherein the at least one scheduling node (320) is configured to: Receiving at least two friction data messages (M(μ)) associated with a particular track segment (310) e ,ID 310 ,t1)), Based on the at least two received friction data messages (M(μ e ,ID 310 , t1)) to derive an updated value of the friction coefficient of the track segment (310), the updated value of the friction coefficient being based on the data included in the at least two friction data messages (M(μ e ,ID 310 ,t1)) in the friction coefficient (μ e ) of the verification value, and The updated value of the coefficient of friction of the track section (310) is communicated to at least one of the receiver devices (110) in the set of receiver devices via a friction data message (M) sent out over the wireless interface.

9. The system of claim 8, wherein the friction coefficient (μ e ) includes: The at least two received friction data messages (M(μ e ,ID 310 ,t1)) of each of the friction coefficients (μ e ) is compared with a threshold level of the friction coefficient, and If the at least two received friction data messages (M(μ e ,ID 310 ,t1)) the friction coefficient (μ) of the latest received message e ) is lower than or equal to the threshold level, the updated value of the friction coefficient is assigned to be equal to the friction coefficient (μ) of the most recently received message e ), otherwise, The updated value of the coefficient of friction is assigned to be equal to the threshold level of coefficient of friction.

10. The system of claim 8, wherein the friction coefficient (μ e ) includes: The updated value of the friction coefficient is assigned to the at least two received friction data messages (M(μ e ,ID 310 ,t1)) the friction coefficient (μ) of the latest received message e )’s verification value.

11. A computer-implemented method for data communication in a railway network (300), the method being implemented in at least one processing circuit (430) and comprising: A measurement controller (130) included in a data provider type rail vehicle (100) is provided to obtain a friction coefficient (μ) related to a section (310) in the railway network (300). e ), A verification value of the basic parameter (μ) is generated in the measurement controller (130), the verification value reflecting an updated friction coefficient (μ) between the rail (140) of the track section (310) and the wheels (151, 152, 153, 154) of a corresponding one of the at least one rail vehicle (100) of the data provider type. e ), and the verification value is generated by a process involving the following: measuring the respective rotational speeds (ω1, ω2, ω3, ω4) of a specific one of the axles to which the wheels (151, 152, 153, 154) of at least one first rail vehicle are connected while applying a gradually increasing braking force (BF) to the axle, determining an absolute difference between the rotational speed (ω2) of the particular one of the axles and an average rotational speed of the axles other than the particular one of the axles while applying the gradually increasing braking force (BF), and in response to the absolute difference exceeding a threshold: The friction coefficient (μ e ) of the measured value (μ m ); Check the friction coefficient (μ e ) is within the acceptance interval from the basic parameter (μ), and if so, then The verification value is assigned to be equal to the friction coefficient (μ e ), and A data transmission including the friction coefficient (μ) is sent from a transmitter device (120) included in the rail vehicle (100) of the data provider type. e ) of the verification value of the friction data message (M(μ e ));as well as The friction data message (M(μ) is received in a receiver device (110) included in a rail vehicle (100, 312, 313, 314) in the railway network (300). e )).

12. The method according to claim 11, comprising: The friction data message (M(μ) is received in each receiver device (110) in the set of receiver devices via a wireless interface. e )),as well as The friction data message (M(μ)) is sent from each of the at least one transmitter device (120) through the wireless interface e )).

13. The method according to claim 12, comprising: The friction data message (M(μ) is generated in each of at least one measurement controller (130) e )、M(μ e ,ID 310 ,t1)) to include: the friction coefficient (μ e ) and the friction coefficient (μ e ) of the track segment (310) associated with the verification value 310 ), and in deriving the friction coefficient (μ e ) is the time point (t1) when the verification value is obtained.

14. The method according to claim 13, comprising, in each receiver device (110) in the set of receiver devices: Receiving at least two friction data messages (M(μ)) associated with the track segment (310) e )),as well as Based on at least two received friction data messages (M(μ e )) to derive an updated value of the friction coefficient of the track segment (310), the updated value of the friction coefficient being based on the data included in the at least two friction data messages (M(μ e )) in the friction coefficient (μ e )’s verification value.

15. The method according to claim 14, wherein the friction coefficient (μ e ) includes: The at least two received friction data messages (M(μ e The friction coefficient (μ) of each of e ) is compared with a threshold level of the friction coefficient, and If the at least two received friction data messages (M(μ e The friction coefficient (μ) of the latest received message in e ) is lower than or equal to the threshold level, the updated value of the friction coefficient is assigned to be equal to the friction coefficient (μ) of the most recently received message e ), otherwise, The updated value of the coefficient of friction is assigned to be equal to the threshold level of coefficient of friction.

16. The method according to claim 14, wherein the friction coefficient (μ e ) includes: The updated value of the friction coefficient is assigned to the at least two received friction data messages (M(μ e The friction coefficient (μ) of the latest received message in e )’s verification value.

17. The method according to any one of claims 13 to 16, further comprising: The friction data message (M(μ)) is received in at least one scheduling node (320) from one of the at least one transmitter device (120) via the wireless interface. e ,ID 310 ,t1)), and The received friction data message (M) is communicated to at least one of the receiver devices (110) of the set of receiver devices via the wireless interface.

18. The method according to claim 17, further comprising, in the scheduling node: Receiving at least two friction data messages (M(μ)) associated with a particular track segment (310) e ,ID 310 ,t1)), Based on the at least two received friction data messages (M(μ e ,ID 310 , t1)) to derive an updated value of the friction coefficient of the track segment (310), the updated value of the friction coefficient being based on the data included in the at least two friction data messages (M(μ e ,ID 310 ,t1)) in the friction coefficient (μ e ) of the verification value, and The updated value of the coefficient of friction of the track section (310) is communicated to at least one of the receiver devices (110) in the set of receiver devices via a friction data message (M) sent out over the wireless interface.

19. The method according to claim 18, wherein the friction coefficient (μ e ) includes: The at least two received friction data messages (M(μ e ,ID 310 ,t1)) of each of the friction coefficients (μ e ) is compared with a threshold level of the friction coefficient, and If the at least two received friction data messages (M(μ e ,ID 310 ,t1)) the friction coefficient (μ) of the latest received message e ) is lower than or equal to the threshold level, the updated value of the friction coefficient is assigned to be equal to the friction coefficient (μ) of the most recently received message e ), otherwise, The updated value of the coefficient of friction is assigned to be equal to the threshold level of coefficient of friction.

20. The method according to claim 18, wherein the friction coefficient (μ e ) includes: The updated value of the friction coefficient is assigned to the at least two received friction data messages (M(μ e ,ID 310 ,t1)) the friction coefficient (μ) of the latest received message e )’s verification value.

21. A computer program (425) loadable into a non-volatile data carrier (420) communicatively connected to at least one processor (430), the computer program (425) comprising software for executing a method according to any one of claims 11 to 20 when the computer program (425) is run on the at least one processor (430).

22. A non-volatile data carrier (420) comprising a computer program (425) according to claim 21.

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