System for contactless position determination of mechanical components of a railway track device

Abstract

The invention relates to a system for contactless position determination of a mechanical component (1) relative to another mechanical component (2) of a railway track device, the system comprising: at least one reference position unit (3) attachable to one of the mechanical components (1, 2) of the railway track device and comprising a magnetic field source (5); at least one position detection sensor (4) comprising at least two independent magnetic field measurement units (6, 7) and attachable to the other one of the mechanical components (1, 2) of the railway track device; wherein for a predetermined correct relative position or positions of the mechanical components (1,2), the at least one position detection sensor (4) remains in the range of a magnetic field produced by the magnetic field source (5). The system furthermore comprises an evaluation unit (10) comprising at least two interconnected, independent safety processing units (12) each connected to at least one of the magnetic field measurement units (6, 7), wherein the evaluation unit (10) is configured to evaluate in a safe manner whether the position of the reference position unit (3) is within permissible limits, taking into consideration independent evaluations performed by the at least two safety processing units (12) based on the signals and / or information from the respective magnetic field measurement units (6, 7), wherein each of the said evaluations consists in classifying the said signals and / or information as proper or improper by comparing with at least one predetermined boundary value. The invention relates also to a railway track device comprising stationary and / or movable mechanical components (1, 2) and the system for contactless position determination according to the present invention.

Description

[0001] 59P53237PC00 1

[0002] SYSTEM FOR CONTACTLESS POSITION DETERMINATION OF MECHANICAL COMPONENTS OF A RAILWAY TRACK DEVICE

[0003] Technical field

[0004] The present invention relates generally to position determination of movable and stationary mechanical parts in the railway track area, and in particular to a safety related system for automatized position measurement and determination of mechanical parts in railway track devices such as points and their associated devices or rail expansion joints, in order to reduce human effort involved in inspections of the railway track devices and to provide a higher level of safety.

[0005] Background art

[0006] Railway track devices are a group of railway devices ensuring proper functioning of the railway infrastructure, especially the tracks on which railway vehicles move. Among this group, a point, also known as a turnout or a railroad switch, is one of the important track assets in the railway system, and is responsible for changing the direction of moving railway vehicles to different tracks. Depending on the controllable point position, railway vehicles are directed to one of the different tracks, enabling the control over the railway route travelled by the railway vehicles, e.g. trains, trams, underground (metro) trains, elevated trains, etc. There are many different types of points, such as: simple points, double slip points, single slip points, moveable switch diamond crossings or derailers. They are equipped with field devices such as actuators called point machines for driving the movement of the point, end position locking devices for locking movable parts in requested positions, and control devices called end position controllers indicating the position of moving parts of the point.

[0007] Safe conditions for railway operations require proper maintenance of the point, especially mechanical devices in the point, such as switches, crossings, switch drives, crossing drives, end position controllers, locking devices. The maintenance activities focused on verification of the technical condition of the point in the context of its safety are often referred to as an inspection and in most cases are part of the legal regulations concerning the railway operations. In practice, the above requires periodic checking of the distances between moving parts to ensure that the actual distances are within permissible limits, ensuring safe operation of the devices. Such checking typically consists in measuring the distances between selected mechanical components, especially movable ones, and are most often performed by qualified 59P53237PC00 2 technical personnel responsible for maintaining the track and track devices. The same applies to other railway devices with movable parts, e.g. rail expansion joints.

[0008] The work of technical personnel in the track environment is hard, expensive and dangerous. Inspecting railway track devices such as a point and other mechanical devices requires attention and care, which makes it time-consuming and laborious. Measurements are typically performed on site using various measuring devices, from very simple ones (probes, calipers) to relatively complex devices (e.g. laser distance measuring sets). The accuracy of measurements performed by technical personnel may be susceptible to errors due to human errors. The work is carried out outdoors and may be hindered by weather conditions (rain, snow, wind, icing, etc.). The inspection teams have to move to the remote locations which requires preparations and logistics. Last but not least is the fact that for the time of inspections the traffic of trains is stopped or at least reduced.

[0009] For the above reasons, actions are being taken to improve the efficiency of inspections of railway track devices, e.g. by automatic measurements, but with reduced human involvement.

[0010] Prior art

[0011] There are many methods used in many technical domains, especially in automotive industry, for determining the position of mechanical parts. The most popular are contactless methods based on the measurement of the change in the magnetic field. In this group, many different magnetic sensors are used, such as Hall effect sensors, MR sensors, AMR sensors, GMR sensors, TMR sensors, inductive sensors and others. There are other sensing technologies available, such as potentiometers, ultrasonic sensors, lidar and laser sensors, but with known disadvantages in comparison to the magnetic sensors. As one example, JP2008101932A discloses a magnetic position detector capable of restraining the number of part items for various kinds of parts related to magnetic position detection.

[0012] Technical problem

[0013] Railway track conditions are very demanding and the development of an adequate technical solution to support the railway track device inspections is a great challenge due to many aspects and technical problems that need to be taken into account, such as harsh environment, relatively low precision / fit of mechanical devices in the tracks, dimensional tolerances, stability of measurement parameters over a long lifespan, high reliability needed 59P53237PC00 3 etc. Additionally, due to the influence on safe railway operations, the technical solution should fulfil the respective safety requirements.

[0014] Object of the invention

[0015] Taking into consideration the above-mentioned issues and challenges there is a need to provide a robust technical solution capable to be used in the railway track area which would reduce the need of manual work in the track and would provide a high level of safety.

[0016] Summary of the invention

[0017] The present invention provides a system for contactless position determination of a mechanical component relative to another mechanical component of a railway track device, the system comprising at least one reference position unit attachable to one of the mechanical components of the railway track device and comprising a magnetic field source, at least one position detection sensor comprising at least two independent magnetic field measurement units and attachable to the other one of the mechanical components of the railway track device, wherein for a predetermined correct relative position or positions of the mechanical components, the at least one position detection sensor remains in the range of a magnetic field produced by the magnetic field source. The system comprises also an evaluation unit comprising at least two interconnected, independent safety processing units each connected to at least one of the magnetic field measurement units, wherein the evaluation unit is configured to evaluate in a safe manner whether the position of the reference position unit is within permissible limits, taking into consideration independent evaluations performed by the at least two safety processing units based on the signals and / or information from the respective magnetic field measurement units, wherein each of the said evaluations consists in classifying the said signals and / or information as proper or improper by comparing with at least one predetermined boundary value.

[0018] According to another preferred embodiment of the system, the position detection sensor comprises one or more additional sensors for detecting environmental or technical conditions, selected at least from acceleration sensors, vibration sensors, inclination sensors, displacement sensors, temperature sensors, humidity sensors, oil level sensors, oil pressure sensors, electric supply power sensors, voltage sensors, current sensors, wherein the one or more additional sensors are connected to at least one of the safety processing units and / or to a separate diagnostic unit. 59P53237PC00 4

[0019] According to still another preferred embodiment of the system, the system comprises one or more additional external binary sensors each indicating one of the predetermined states of an associated component of the railway track device, wherein the one or more additional external binary sensors are connected to at least one of the safety processing units and / or to a separate diagnostic unit.

[0020] According to still another preferred embodiment of the system, the magnetic field source is a constant magnetic field source, in particular a magnet or a coil.

[0021] According to still another preferred embodiment of the system, the magnetic field measurement units are selected at least from Hall effect sensors, MR sensors, AMR sensors, GMR sensors, TMR sensors or inductive sensors.

[0022] According to still another preferred embodiment of the system, each of the magnetic field measurement units is configured to perform measurements in at least two axes.

[0023] According to still another preferred embodiment of the system, the magnetic field measurement units are stacked together, preferably integrated in one component.

[0024] According to still another preferred embodiment of the system, the magnetic field measurement units are arranged side by side and in a common plane with the magnetic field source constitute the vertices of a triangle.

[0025] According to still another preferred embodiment of the system, the magnetic field measurement units are arranged at a predetermined distance to each other, and the evaluation unit is configured to determine the perpendicular distance from the mechanical component using geometrical dependencies of a triangle, whose vertices are taken as positions of the magnetic field measurement units and the magnetic field source.

[0026] According to still another preferred embodiment of the system, the evaluation unit furthermore comprises a communication unit configured to provide communication between its internal units and with an external system and to transmit to the external system information about the position of the mechanical component and / or information about the environmental and technical conditions, and a cryptographic circuit configured to authenticate, authorise and encrypt the communication.

[0027] According to still another preferred embodiment of the system, the evaluation unit furthermore comprises a configuration unit connected to the communication unit, wherein the configuration unit contains configuration information for configuring the expected operation of internal units and circuits of the evaluation unit. 59P53237PC00 5

[0028] According to still another preferred embodiment of the system, the system furthermore comprises a magnetic field reference unit arranged inside or outside the position detection sensor, and the evaluation unit is configured, respectively, to monitor the sensitivity of the position detection sensor or to detect the loss of sensitivity based on the known magnetic field produced by the magnetic field reference unit.

[0029] According to still another preferred embodiment of the system, the evaluation unit is equipped with an NFC interface connected to or integrated into the communication unit, the NFC interface being capable of exchanging the diagnostic, configuration and safety-related information with other NFC-enabled devices.

[0030] The present invention furthermore provides a railway track device comprising stationary and / or movable mechanical components and the system for contactless position determination as defined in any one of the above embodiments.

[0031] According to one preferred embodiment of the railway track device, the railway track device is selected at least from: a point and its equipment including switches and switch drives, crossings and crossing drives, end position controllers, locking devices and mechanisms; and a rail expansion joint.

[0032] The system according to the invention meets high safety and security requirements. Whenever used in this specification and claims, the term “safety” means freedom from unacceptable risk. In railway systems the system safety is classified into five safety integrity levels (SIL), where 0 is the lowest level, and 4 is the highest level. Safety integrity is defined by standards as “ability of safety-related system to achieve its required safety functions under all the stated conditions within a stated operational environment and within a stated duration” (EN 50126-1). In railway systems, vital (i.e. safety-related) systems require most often SIL3 up to SIL4.

[0033] On the other hand and in contrast to the term “safety”, the term “security” is to be understood in the following meaning: a system or service is considered to be secure to the extent that its users can rely on that it functions (or will function) in the intended way.

[0034] In the context of the present invention, whenever the term “track device” or “railway track device” is used, it should be construed as any device installed in the track or in its vicinity and having mechanical components that are movable or stationary with respect to each other and whose relative position is to be measured or determined for the safety of operation. 59P53237PC00 6

[0035] Furthermore, in the context of the present invention, the terms “railway” or “rail” refer to the infrastructure that enables the movement of various types of rail vehicles, including trains, trams, underground (metro) trains, elevated trains, etc., and includes also monorail systems.

[0036] As an example, track devices cover points and their equipment (such as switches and switch drives, crossings and crossing drives, end position controllers, locking devices and mechanisms) and others, as well as single track devices such as rail expansion joints and their equipment and others. Furthermore, when reference is made to measuring or determining the position of a mechanical component or components, this may refer to a component or components that are stationary or to a component or components that are movable. This also includes the case where one component is stationary and the other is movable, the case where both components are stationary, as well as the case where both components are movable. A stationary mechanical component can be understood as any mechanical component which is permanently attached, mounted, installed or fixed to another stationary part of a railway track device or some other stationary object that is present on or near the track, or to the track itself. A movable mechanical component can be understood as any mechanical element which, in connection with the function it performs, is movable in at least one direction. Mutual position of these mechanical components is of great importance for the correct and safe railway traffic.

[0037] As one example, in case of a point representing one possible railway track device, stock rails are stationary mechanical components, whereas switch toes and switch rails are movable mechanical components. Similarly, a crossing nose (frog) can be a movable mechanical component. As another example, in case of a driving device such as a point machine representing another possible railway track device, a housing of the driving device is a stationary mechanical component, whereas a driving (switch) rod and control (detection) rods are movable mechanical components. Parts of a locking circuit are also movable mechanical components.

[0038] As still another example, in case of a rail expansion joint representing another possible railway track device, two parts of a rail (jaw and tongue) can be movable mechanical components.

[0039] These are merely some examples to facilitate understanding the invention, and one skilled in the art will be aware of many other possible railway track devices comprising other types of stationary and movable mechanical components, which are not directly mentioned here, but are covered by the defined scope, and whose relative position(s) can be monitored by 59P53237PC00 7 the system according to the present invention with increased safety. Furthermore, following the indicated examples, one skilled in the art will be able to easily identify other stationary and movable mechanical components or elements in various railway track devices.

[0040] The solution according to the present invention provides a number of advantages. First of all, the system provides vital (i.e., safety-related) information about the position of a mechanical component or components. The combination of the magnetic, contactless sensing technologies and the evaluation unit leads to a smart solution highly integrating vital and non- vital functionalities, thereby significantly reducing complexity, cabling, and the number of required devices. As a result, the inspection of points could be transformed in such a way that the physical presence of people in track could be replaced by the automatised measurement with the required level of safety and security of the information provided remotely.

[0041] Finally, the additional sensors included in the system and / or outside it provide substantial additional benefits that arise from the comprehensive available information supporting the maintenance processes and / or safety aspects of points and other railway track devices.

[0042] Further features and advantages of the present invention will become apparent after reading a more detailed description of exemplary embodiments presented below in connection with the attached drawings, in which:

[0043] Fig. 1 is a schematic illustration of a system for contactless position determination of a mechanical component of a railway track device.

[0044] Fig. 2 is a schematic illustration of an extended configuration of a system for contactless position determination of a mechanical component of a railway track device.

[0045] Fig. 3a is a schematic illustration of one possible configuration of mechanical components and attached components of the system for contactless position determination.

[0046] Fig. 3b shows the configuration from Fig. 3a in spatial view.

[0047] Fig. 4a is a schematic illustration of another possible configuration of mechanical components and attached components of the system for contactless position determination.

[0048] Fig. 4b shows the configuration from Fig. 4a in spatial view.

[0049] Figs. 5a and 5b illustrate two possible arrangements of magnetic field measurement units. 59P53237PC00 8

[0050] Fig. 6 is a schematic illustration explaining the principle of position determination in the arrangement from Fig. 5b.

[0051] Detailed description

[0052] Fig. 1 shows a schematic illustration of a system for contactless position determination of a mechanical component of a railway track device. The railway track device (not shown in its entirety in the figure) comprises two mechanical components 1, 2 which are movable with respect to each other. These mechanical components 1, 2 may be own components of the railway track device or may be attached to the railway track device elements. A movable mechanical component 1 of the railway track device can be moved in lateral directions (left / right as indicated by a double- sided arrow in Fig. 1) during its regular operation, however, this is only one example and other movement directions are possible as well. A stationary mechanical component 2 of the railway track device remains fixed in its position during regular operation. It is the role of the system for contactless position determination according to the present invention to measure the relative position of these two mechanical components 1, 2 to ensure safe operation of the railway track device. The railway track devices can be, for example, points and their equipment (such as switches and switch drives, crossings and crossing drives, end position controllers, locking devices and mechanisms) and others, as well as single track devices such as a rail expansion joints and their equipment and others, each having mechanical components of suitable shape and configuration and in a specific relationship, e.g. movable with respect to each other or stationary at some distance to each other, etc.

[0053] The system for contactless position determination presented in Fig. 1 comprises a reference position unit 3 assigned and attached to the movable mechanical component 1 and a position detection sensor 4 assigned and attached to the stationary mechanical component 2, wherein the reference position unit 3 and the position detection sensor 4 are located on the two opposing sides or surfaces of the respective mechanical components 1, 2 such that they face towards each other without any other metal component therebetween. For example, they could by attached to the respective mechanical components 1, 2 by any suitable means (glued, screwed etc.) or positioned inside or recessed in the components 1, 2, if this is technically possible and acceptable. It is also possible to provide an alternative arrangement in which the reference position unit 3 is assigned to the stationary mechanical component 2, and the position detection sensor 4 is assigned to the movable component 1. 59P53237PC00 9

[0054] The reference position unit 3 comprises a magnetic field source 5, e.g. a permanent magnet or a coil supplied with constant current, which produces a magnetic field, and the position detection sensor 4 comprises a first magnetic field measurement unit 6 and a second magnetic field measurement unit 7 connected to an evaluation unit 10. The relative position of the magnetic field source 5 and the position detection sensor 4 is such that the magnetic field measurement units 6, 7 remain in the range of the magnetic field produced by the magnetic field source 5 to be able to detect the predetermined correct relative position(s) of the mechanical components 1, 2. As a result, the position-dependent magnetic field of the magnetic field source 5 (as seen by the position detection sensor 4) can be constantly detected and measured by the magnetic field measurement units 6, 7. These measurement correspond to the relative position of the two mechanical components 1, 2. In a still condition, the presence and position of the magnetic field source 5 can be determined in a safe and reliable manner by the two independent magnetic field measurement units 6, 7. In case where the movable mechanical component 1 is moved together with the magnetic field source 5 with respect to the stationary mechanical component 2 and the position detection sensor 4 attached to it, the first and second magnetic field measurement units 6, 7 measure corresponding variations of the magnetic field (its strength) produced by the magnetic field source 5, such as a permanent magnet. The measurements performed by the magnetic field measurement units 6, 7 are read and evaluated by the evaluation unit 10, which is described below in more detail.

[0055] The magnetic field measurement units 6, 7 are used for converting the magnitude and variations of a magnetic field into electric signals, and can be implemented in one of the known technologies, including Hall effect sensors, magnetoresistive (MR) sensors, anisotropic magnetoresistive (AMR) sensors, giant magnetoresistance (GMR) sensors, tunnel magnetoresistance (TMR) sensors, inductive sensors, or other suitable magnetic field sensors which are not explicitly mentioned here but are conceivable for the skilled person. Depending on the design, magnetic sensors can be one-dimensional (ID), two-dimensional (2D) or even three-dimensional (3D) magnetic sensors. As a result, depending on the requirements, it is possible to select simple magnetic sensors to provide a very simple output indicating the presence or absence of a magnetic field or an output indicating the strength of a magnetic field, or more advanced magnetic sensors to provide an output indicating magnetic field measurements in a number of axes. In the latter case, it is possible to determine more precisely not only the properties of the measured magnetic field, but also the orientation or angles of the magnetic sensor relative to the measured magnetic field source, such as by using trigonometric 59P53237PC00 10 relations. Knowing the angle and the distance, it is possible to determine the offset, i.e. the position relative to the measuring system.

[0056] The evaluation unit 10 is in communication with the magnetic field measurement units 6, 7 of the position detection sensor 4 using any suitable means, such as wired or cable connection and furthermore provides electrical power to the units 6, 7. The evaluation unit 10 can be positioned in the vicinity of the associated railway track device, preferably it can be embedded or integrated in it, however, depending on the needs, it would be also possible to position the evaluation unit 10 remotely, e.g. at some distance from the position detection sensor 4, for example in another device or as attached to another component. The evaluation unit 10 presented in Fig. 1 comprises two safety processing units 12, a communication unit 13, a cryptographic circuit 14 and a configuration unit 15.

[0057] The first and second magnetic field measurement units 6, 7 of the position detection sensor 4 are connected to the two safety processing units 12, respectively, forming so-called safety channels. As shown by the double arrow, the safety processing units 12 also can communicate with each other, e.g. to exchange input information and processing results. This enables each of the safety processing units 12 to receive signals and other data from both magnetic field measurement units 6, 7 for further processing, so that each safety processing unit 12 is able to check both units 6, 7 independently, and to exchange the processing results, so that the results obtained by each of the safety processing units 12 can be compared to each other and verified. Although not showed in Fig. 1, in one alternative embodiment it would be also possible to provide additional connections from each of the field measurement units 6, 7 to both safety processing units 12. One skilled in the art and in the field of Safety Level Integrity requirements will be aware that these are only exemplary configurations and other connection schemes and configurations are possible, as long as each of the safety processing units 12 can effectively receive signals and other information from the field measurement units 6, 7 and share information with the other one.

[0058] The role of the safety processing units 12 is to determine the relative position of the magnetic field measurement units 6, 7 with respect to the predetermined reference (magnetic field source 5) taking into account signals representing magnetic field levels (strengths or intensities) provided by the magnetic field measurement units 6, 7. The measurement data related to the measured magnetic field is provided from the magnetic field measurement units 6, 7 to the safety processing units 12 in the form of analog or digital signals that are processed 59P53237PC00 11 in a safe way by the safety processing units 12. The quality of data (precision, stability over temperature and time) provided by the measurement units 6, 7 can be also improved by means of replacing a ID measurement unit by a 2D or 3D unit due to the possibility of using calculations based on angles instead of, or in addition to, the strength of the magnetic signal only. The above-mentioned signals are evaluated independently in a safe way, by at least two safety processing units 12, and based on the strengths and direction of the measured magnetic field the distance to the reference point (magnetic field source 5) is determined and compared to the permitted boundary value. Such a boundary or threshold value may be a predetermined value available for both safety processing units 12. Output value data processing must be performed independently in a manner that complies with the normative requirements and standards commonly known to a skilled person in the field of safety and signaling (such as, e.g., Safety Integrity Levels mentioned earlier herein). As a result, binary information about the proper or improper position of the two elements under observation is developed. The decision about the proper or improper position is developed taking into consideration the measured distance that is compared to the boundary value with the use of a methodology typical for the safety related systems. In addition, the precise information about the measured distance is available. Both safety processing units 12 are connected to the communication unit 13 which performs communication to an external system and shares the information about the determined position of the relevant mechanical component or part. To this end, the communication unit 13 is also connected to the cryptographic circuit 14 and to the configuration unit 15, and coordinates the exchange of information internally, i.e. between internal units and circuits, and externally, i.e. with the external systems 11 and / or other external entities. The cryptographic circuit 14 is used to support the security related requirements e.g. for authentication, authorisation and encryption of communication with external systems, such as the external system 11 presented in Fig. 1 and connected to the communication unit 13. In this way, the external system 11 can receive information indicating the determined position of the mechanical component in a safe and secure manner. In practice, the external system 11 could be a vital signaling system operating as SIL3 or SIL4 system or an advanced information system supporting the maintenance process or it could be a simple system switching binary its output state depending on the determined position of the monitored mechanical component. As known in the field of railway safety, any deviation from the previously defined safety range, such as e.g. the position of a mechanical component determined by the system according to the present invention to be outside the permissible limits, causes appropriate actions to be triggered, such as blocking or closing a given track section, sending appropriate warning or alarm signals, etc., 59P53237PC00 12 to prevent any risks associated with potential malfunction of the monitored railway track devices.

[0059] One of the most important advantages of the system according to the invention is that by doubling (or multiplying in general) the safety channels, it is possible to increase control over the proper operation of railway track devices in terms of safety. One skilled in the art will also be aware that the system according to the present invention is not limited to two channels, each comprising a magnetic field measurement unit and a safety processing unit for processing its signal, as presented in the above example. The position determination safety can be further increased by providing more such channels, e.g. three, four or more. Adding more channels e.g. to improve the reliability of the system or to increase the accuracy and precision would mean providing more magnetic field measurement units each with a safety processing units assigned to it, which is also covered by the scope of the present invention.

[0060] The configuration unit 15 contains configuration information for configuring the expected behavior of the safety processing units 12 and other internal units and circuits of the evaluation unit 11, e.g. values of parameters needed to develop the information about the position, such as boundary values, calibration coefficients, parameters necessary for internal and external communication and information related to the version of hardware and software. The above information is shared internally between the configuration unit 15, the safety processing units 12, the communication unit 13, and other units of the evaluation unit 11 (including the diagnostic unit described later in this specification).

[0061] As presented in Fig. 1, the position detection sensor 4 may furthermore comprise an internal magnetic field reference unit 8. This internal magnetic field reference unit 8 produces a magnetic field having a known value, that is used by the evaluation unit 11 to verify the sensitivity of the position detection sensor 4 when the magnetic field from the reference position unit 3 (i.e. produced by the magnetic field source 5) is not present, what is advantageous in safety systems and could be used e.g. for testing the system. Depending on the application, the internal magnetic field reference unit 8 can be integrated inside the position detection sensor 4 (as presented in Fig. 1) to verify its sensitivity, or can be a separate external entity arranged outside the position detection sensor 4 (not shown in Fig. 1) and connected to the mechanical component 2, that provides the evaluation unit 10 with the possibility to detect that the position detection sensor 4 is not fixed to the mechanical component 2, for example in the event of detachment or falling off. 59P53237PC00 13

[0062] Fig. 2 shows an extended configuration of a system for contactless position determination of a mechanical component according to the present invention. This configuration corresponds for the most part to the previous configuration of the system presented in Fig. 1 and for similar elements the same reference numbers are provided. The overlapping description is therefore not repeated here and mainly the differences of the extended configuration in Fig. 2 are explained.

[0063] Furthermore, for the sake of clarity, only the position detection sensor 4 and the evaluation unit 10 are shown, as these two components are modified in this configuration. The components 4, 6, 7 have already been described with reference to Fig. 1, therefore the excessive description is omitted here.

[0064] Due to high flexibility and expandability of the evaluation unit 10, it is possible to add additional sensors as vital or non-vital parts of the system, which means that said sensors can play an important role in terms of safety or support the functioning of the system. In the presented configuration, additional sensors denoted as 17 and 18 have been introduced in the position detection sensor 4. Sensors 17, 18 can be arranged in various ways inside the position detection sensor 4 and their number can be smaller or larger than shown in this example. The sensor 17 (or possibly more sensors than shown in Fig. 2) is connected to the safety processing unit 12 of the evaluation unit 10 as an example, while the other sensors collectively denoted as 18 are connected to a separate diagnostic unit 16 provided in the evaluation unit 10 and connected to the communication unit 13. Although for simplicity the sensors 18 are illustrated as connected in series in Fig. 2, it will be understood that each of the sensors 18 (and sensors 17 in case of a greater number thereof) is connected to and can communicate with the diagnostic unit 16 or the safety processing unit 12, e.g. using a parallel connection, a bus or any other suitable connection scheme. Alternatively, all the sensors 18 can be also connected to the safety processing unit 12, if required (as in the case where they have a safety-related function). The sensors 17, 18 can be used to monitor the status of the measuring system or for additional monitoring of the status of the track equipment or environmental conditions relevant to the operation of the track equipment. In this way, a given sensor can be “vital” (or safety-related) and connected to the safety processing unit 12 or “non-vital” and connected to the diagnostic unit 16. Other configurations are also possible, for example the diagnostic unit 16 may use the communication unit 13 for forwarding measurements data to the safety processing unit(s) 12 to be taken into account in the evaluation. 59P53237PC00 14

[0065] The role of the diagnostic unit 16 is to receive and process signals and data from the sensors connected thereto in order to determine, e.g., whether the parameters derived from the signals are within permissible limits. The status of parameters or exceeding the permissible limits can be transmitted to the communication unit 13 and then further to external units. In alternative implementations, the diagnostic unit 16 can also be integrated with the communication unit 13 or with the safety processing unit 12. As sensors 17, 18 any available sensors can be used, such as temperature sensors, humidity or ice sensors, vibration sensors, acceleration sensors, oil level, oil pressure, electric supply power, voltage, current or others. The number, type and connection of additional sensors depend on the needs. The diagnostic unit 16, as one of the internal units of the evaluation unit 10, can send information to other units as well as receive information from other units via the communication unit 13, such as configuration information and others. As a result, the diagnostic unit 16 can be taken into account not only internally within the evaluation unit 10 but also externally, for example by transmitting diagnostic information to external systems.

[0066] The temperature sensor could provide the safety evaluation unit 10 with information that supports effective compensation of temperature-dependent changes influencing the system accuracy and precision. The temperature sensor can be also integrated into at least one of the magnetic field measurement units 6, 7.

[0067] The acceleration sensor could provide information about the acceleration, vibration, displacement and inclination of the metal parts during the change of the point position or during the passage of the train. The above information could be additionally used to detect the technical condition of the fixation / attachment of the metal parts e.g. to detect loosed screws or the technical condition of supporting elements such as sleepers, or fixation of the point machines.

[0068] The humidity sensor could provide valuable information about the presence of water or excessive humidity in the devices such as point machines or locking devices.

[0069] Depending on the character of the information provided by the sensors above, they can be connected to the safety processing units 12 in order to develop the vital or non-vital information. Alternatively, in case the non-vital information is needed, the sensor could be connected to the diagnostic unit 16 processing the non-vital information. This additional information related to the environmental conditions or to the technical condition of fixation and supporting element can be shared by the evaluation unit 10 with the external systems through the communication unit 13. 59P53237PC00 15

[0070] It is obvious for the skilled person that according to the above concept other sensors, standalone or integrated, could be used as well, such as, e.g., vibration sensors, inclinometers, gyroscopes etc.

[0071] Furthermore, in addition or as an alternative to the sensors 17, 18, it is possible to add additional external binary sensors as vital or non-vital parts of the system, which means that said external binary sensors can play an important role in terms of safety or support the functioning of the system. In the presented configuration, additional external binary sensors denoted as 19 and 20 have been introduced externally to the evaluation unit 10 and connected to it. External binary sensors 19, 20 can be arranged in various ways outside the evaluation unit 10 and their number can be smaller or larger than shown in this example. The external binary sensors collectively denoted as 19 are connected to the safety processing unit 12 of the evaluation unit 10 as an example, while the other external binary sensors collectively denoted as 20 are connected to the diagnostic unit 16. Alternatively, all the external binary sensors 19 can be also connected to the safety processing unit 12, if required (as in the case where they have a safety-related function). Although for simplicity the external binary sensors 19, 20 are illustrated as connected in series in Fig. 2, it will be understood that each of the external binary sensors 19, 20 is connected to and can communicate with the safety processing unit 12 or with the diagnostic unit 16, e.g. using a parallel connection, a bus or any other suitable connection scheme.

[0072] The external binary sensors 19, 20 can be used to monitor the status of the measuring system or for additional monitoring of the status of the track equipment or environmental conditions relevant to the operation of the track equipment. In this way, a given external binary sensor can be “vital” (or safety-related) and connected to the safety processing unit 12 or “non- vital” and connected to the diagnostic unit 16.

[0073] The external binary sensor 19 can be used as a vital binary input from a classic end position controller of the track equipment, which comprises a power source (continuous or periodic), at least one end position controller contactor contact and an input device for processing binary information of "0" or "1".

[0074] The external binary sensors 20 can be used for non-vital system state monitoring like system housing integrity, cover opening, fire detection, detection of exceeding the specified operating conditions (e.g. temperature, humidity, flooding, shocks, etc.) . 59P53237PC00 16

[0075] To provide some illustrative examples, the external binary sensors could indicate whether a housing or a cover is in its place (first binary state) or is removed (second binary state), or whether a given monitored mechanical component has reached its end position (first binary state) or not (second binary state), or whether the specified condition has occurred (first binary state) or not (second binary state), etc.

[0076] Similarly as in the case of the sensors 17, 18, signals and information provided by the external binary sensors 19, 20 can be taken into consideration by the evaluation unit 10 when evaluating the safe condition of the railway track device. Typically, in case where the safety processing units 12 evaluate the vital (safety-related) sensor data, all output states determined by the external binary sensors 19, 20 must comply with predetermined values or levels for the track device status to be considered safe. In case where the diagnostic unit 16 evaluate the non- vital sensor data, output states determined by the external binary sensors 19, 20 and other additional sensors can be used e.g. for generating notifications about inspection or maintenance needed in the near future.

[0077] Although not shown in Figs. 1 and 2, the evaluation unit 10 can also be equipped with a near-field communication (NFC) interface capable of exchanging all relevant information, including diagnostic, configuration and safety-related information, with other electronic devices wirelessly. Such an NFC interface can be connected to or integrated with the communication unit 13 and can be used for communication with smartphones, tablets or any other standard or dedicated devices equipped with a compatible NFC interface. This provides an additional advantage of eliminating the need for a specialized connector resistant to environmental conditions, and at the same time a very short transmission range (usually a few centimeters) requires both devices to be close together, so that the risk that an outsider will try to interfere is limited.

[0078] As mentioned earlier, the mechanical components 1, 2 may have different shapes and configurations depending on the given type of the railway track device, and the reference position unit 3 and the position detection sensor 4 may be attached to the respective mechanical components in various ways. Figures 2a, 2b and 3a, 3b show some possible configurations of such arrangements.

[0079] Figs. 3a and 3b illustrate one possible configuration of mechanical components and attached components of the system for contactless position determination in schematic and spatial views. The movable mechanical component 1 of the railway track device has the form 59P53237PC00 17 of a rod which moves laterally as indicated by a double-sided arrow in Fig. 3a, whereas the stationary mechanical component 2 of the railway track device has the form of a housing with a through hole through which the rod is inserted and can be freely moved in the direction of its longitudinal axis. The rod is connected to other parts of the railway track device (not shown) and its position relative to the housing is to be determined. The reference position unit 3 comprising the magnetic field source 5 is entirely recessed into the rod in its bottom part such that no part of it protrudes beyond the body of the rod. As a result, the rod can be moved through the hole without the risk that the reference position unit 3 will catch on the housing. The housing (i.e. the stationary mechanical component 2) has a support protruding upwards in the central part of the bottom, on top of which the position detection sensor 4 is attached. The dimensions of the support are selected such that the first and second magnetic field measurement units 6, 7 are located close to the bottom side of the rod. When moving the rod along its longitudinal axis, the magnetic field source 5 moves over the units 6, 7. Based on magnetic field detection, the system of the present invention is able to determine that both mechanical components 1, 2 are in a predetermined position relative to each other.

[0080] Figs. 4a and 4b illustrate another possible configuration of mechanical components and attached components of the system for contactless position determination in schematic and spatial views. This configuration is in most aspects similar to the previous configuration, so only the differences between the both configurations will be discussed here. In the configuration presented in Figs. 4a and 4b, only a part of the movable mechanical component 1 has the form of a rod. To one end of the rod (located inside the housing) a structural element is attached with a complex geometric shape adapted to a specific function of the railway track device (no further details are presented herein as the invention is focused on relative positon of the mechanical components 1, 2). The reference position unit 3 comprising the magnetic field source 5 is attached to the bottom part of the structural element, in particular to one of the flat surfaces selected such that the magnet 5 moves over the units 6, 7 during the movement of the movable mechanical component 1. Based on magnetic field detection, the system of the present invention is able to determine that both mechanical components 1, 2 are in a predetermined position relative to each other.

[0081] Figs. 5a and 5b illustrate two possible arrangements of magnetic field measurement units. For ease of understanding, only the relevant elements of the system are shown. In both arrangements, magnetic field measurement units 6, 7 are arranged inside the position detection 59P53237PC00 18 sensor 4 and detect a magnetic field produced by the magnetic field source 5 of the reference position unit 3.

[0082] According to the arrangement shown in Fig. 5a, the magnetic field measurement units 6, 7 are stacked together so that they are very close to each other. In some realizations, both magnetic field measurement units 6, 7 can be integrated in a single component . The advantage of this arrangement is high compactability and miniaturization. Smaller sensor size can be advantageous for embedded systems because it takes up less space and is suitable for use in currently existing devices with little space.

[0083] According to the arrangement shown in Fig. 5b, the magnetic field measurement units 6, 7 are arranged side by side at a certain distance from each other.. As furthermore illustrated in Fig. 5b, mutual arrangement of the elements 5, 6 and 7 is such that a common plane can be defined in three-dimensional space which includes all these elements 5, 6 and 7. Therefore, they can be seen as forming the vertices of a triangle marked in the figure with a dashed line.

[0084] Reference will be made now to Fig. 6 which explains the principle of determining the position of a mechanical component, for example in cases where the perpendicular distance of the related parts could vary. The above could happen when the “guidance” of the components is not very precise, due to the wearing or mechanical tolerances, what happens often in railway track conditions.

[0085] For ease of understanding, the elements 5, 6, 7 are illustrated in a simplified form of circles with additional markings for distances and angles. The first and second magnetic field measurement units 6, 7 are arranged next to each other with a known horizontal distance “LI” between them. The magnetic field source 5 of the reference position unit is detected independently by the magnetic field measurement units 6 and 7 having 2D or 3D capabilities (i.e. capable of measuring a magnetic field in two or more axes) and as a result the respective angles a and P are determined. Knowing the values of LI, a and P, the perpendicular distance h can be determined based on well-known geometrical dependencies of a triangle. The above increases the precision of the position measurement and provides information about the precision of the “guidance”.

[0086] The principles of the invention have been explained in detail using specific embodiments presented and discussed above. It should be noted, however, that the scope of the present invention is not limited to the presented specific examples, and many different 59P53237PC00 19 modifications and changes could be made to the invention without departing from its scope defined by the enclosed claims.

[0087] List of reference signs

[0088] 1 movable mechanical component

[0089] 2 stationary mechanical component

[0090] 3 reference position unit

[0091] 4 position detection sensor

[0092] 5 magnetic field source

[0093] 6 first magnetic field measurement unit

[0094] 7 second magnetic field measurement unit

[0095] 8 magnetic field reference unit

[0096] 10 evaluation unit

[0097] 11 external system

[0098] 12 safety processing units

[0099] 13 communication unit

[0100] 14 cryptographic circuit

[0101] 15 configuration unit

[0102] 16 diagnostic unit

[0103] 17 additional sensors (connected to the safety processing unit)

[0104] 18 additional sensors (connected to the diagnostic unit)

[0105] 19 additional external binary sensors (connected to the safety processing unit)

[0106] 20 additional external binary sensors (connected to the diagnostic unit)

Claims

59P53237PC00 20CLAIMS1. A system for contactless position determination of a mechanical component (1) relative to another mechanical component (2) of a railway track device, the system comprising:- at least one reference position unit (3) attachable to one of the mechanical components (1, 2) of the railway track device and comprising a magnetic field source (5);- at least one position detection sensor (4) comprising at least two independent magnetic field measurement units (6, 7) and attachable to the other one of the mechanical components (1, 2) of the railway track device; wherein for a predetermined correct relative position or positions of the mechanical components (1, 2), the at least one position detection sensor (4) remains in the range of a magnetic field produced by the magnetic field source (5);- an evaluation unit (10) comprising at least two interconnected, independent safety processing units (12) each connected to at least one of the magnetic field measurement units (6, 7); wherein the evaluation unit (10) is configured to evaluate in a safe manner whether the position of the reference position unit (3) is within permissible limits, taking into consideration independent evaluations performed by the at least two safety processing units (12) based on the signals and / or information from the respective magnetic field measurement units (6, 7), wherein each of the said evaluations consists in classifying the said signals and / or information as proper or improper by comparing with at least one predetermined boundary value.

2. The system according to claim 1, wherein the position detection sensor (4) comprises one or more additional sensors (17, 18) for detecting environmental or technical conditions, selected at least from acceleration sensors, vibration sensors, inclination sensors, displacement sensors, temperature sensors, humidity sensors, oil level sensors, oil pressure sensors, electric supply power sensors, voltage sensors, current sensors, wherein the one or more additional sensors (17, 18) are connected to at least one of the safety processing units (12) and / or to a separate diagnostic unit (16).59P53237PC00 213. The system according to claim 1 or 2, comprising one or more additional external binary sensors (19, 20) each indicating one of the predetermined states of an associated component of the railway track device, wherein the one or more additional external binary sensors (19, 20) are connected to at least one of the safety processing units (12) and / or to a separate diagnostic unit (16).

4. The system according to any of the previous claims, wherein the magnetic field source (5) is a constant magnetic field source, in particular a magnet or a coil.

5. The system according to any of the previous claims, wherein the magnetic field measurement units (6, 7) are selected at least from Hall effect sensors, MR sensors, AMR sensors, GMR sensors, TMR sensors or inductive sensors.

6. The system according to any of the previous claims, wherein each of the magnetic field measurement units (6, 7) is configured to perform measurements in at least two axes.

7. The system according to any of the previous claims, wherein the magnetic field measurement units (6, 7) are stacked together, preferably integrated in one component.

8. The system according to any one of claims 1 - 6, wherein the magnetic field measurement units (6, 7) are arranged side by side and in a common plane with the magnetic field source (5) constitute the vertices of a triangle.

9. The system according to claim 8, wherein the magnetic field measurement units (6, 7) are arranged at a predetermined distance (LI) to each other, and the evaluation unit (10) is configured to determine the perpendicular distance (h) from the mechanical component (1) using geometrical dependencies of a triangle, whose vertices are taken as positions of the magnetic field measurement units (6, 7) and the magnetic field source (5).

10. The system according to any of the previous claims, wherein the evaluation unit (10) furthermore comprises a communication unit (13) configured to provide communication between its internal units and with an external system (11) and to transmit to the external system (11) information about the position of the mechanical component (1) and / or information about the environmental and technical conditions, and a cryptographic circuit (14) configured to authenticate, authorise and encrypt the communication.59P53237PC00 2211. The system according to claim 10, wherein the evaluation unit (10) furthermore comprises a configuration unit (15) connected to the communication unit (13), wherein the configuration unit (15) contains configuration information for configuring the expected operation of internal units and circuits of the evaluation unit (10).

12. The system according to any of the previous claims, wherein the system furthermore comprises a magnetic field reference unit (8) arranged inside or outside the position detection sensor (4), and the evaluation unit (10) is configured, respectively, to monitor the sensitivity of the position detection sensor (4) or to detect the loss of sensitivity based on the known magnetic field produced by the magnetic field reference unit (8).

13. The system according to any of the previous claims, wherein the evaluation unit (10) is equipped with an NFC interface connected to or integrated into the communication unit (13), the NFC interface being capable of exchanging the diagnostic, configuration and safety-related information with other NFC-enabled devices.

14. A railway track device comprising stationary and / or movable mechanical components (1, 2) and the system for contactless position determination as defined in any one of claims 1 - 13.

15. The railway track device according to claim 14, wherein the railway track device is selected at least from: a point and its equipment including switches and switch drives, crossings and crossing drives, end position controllers, locking devices and mechanisms; and a rail expansion joint.

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