Device for detecting the positions of pivotable parts of railway switches and method for evaluating the signals of sensors for detecting position of pivotable parts of railway switches

Description

The invention relates to a device for detecting and determining different positions of movable parts of railway switches, for example, point rails, and to a method for evaluating the signals of sensors determining the positions of movable parts of switches. As is known, with the ever-widening spread of high-speed railway tracks, the demands on the operation of railway switches are gradually increasing. One of the important prerequisites for safer railway operation is that the train can pass through the railway switches with the greatest possible safety. For this, it is absolutely necessary that the movable parts of the switch, such as the top rails, are moved with the switch adjustment mechanism and can be held in this position precisely after they have been moved. Up to now, a top rail position indicator has been used to monitor these end positions, which was equipped with a mechanical limit switch. However, these mechanical devices are relatively expensive, as they mostly have rods that are easily damaged and therefore often need to be repaired or replaced. In addition to the mechanical position indicators mentioned above, devices are also known that include contactless inductive proximity switches. DE-3511891 discloses a device having an electric motor-driven, individual switch actuator, a lockable actuator and a lockable control slide, as well as a sensor arrangement for detecting the end positions of the slide and determining the safety state. In this solution, the end positions are monitored and the closing position of the control slide and, if applicable, the control slide is monitored using sensors. The signals from the sensors are then transmitted to a control and monitoring unit or a control actuator; in the former, it is determined whether the switch can be driven through. In this solution, the distance measurement of the movable tip rails relative to the fixed main rails is not used. A monitoring device is also known from the patent specification DE-2636359 which monitors the end positions of the movable parts of railway switches. In this case, inductive rail switches are used at specific monitoring points, which cooperate with ferromagnetic counter parts arranged on the movable top rails. It is determined by the inductively generated switch actuation whether the movable rail parts are in their end positions. A method is known from the patent specification EP-514365 for checking the condition of railway switches and determining premature wear in the area of ​​the movable top rails of the switch. In this method, premature wear in the area of ​​the top rails is determined by a sensor, namely by storing the value of the smallest distance measured between the movable top rail and the main rail when passing through the switch, and determining the values ​​of the distances in turn and comparing them with the limit values. In case of exceeding a predetermined limit value, a maintenance command is given. Inductive or capacitive analog sensors are used as sensors in this solution. The inductive proximity switches mentioned above are switching elements of acceptable reliability and wear-free, but they are not suitable for continuously, i.e. permanently, detecting and determining the exact position of the movable parts of the railway switch, they are only suitable for indicating whether one of the end positions of the switch's top rail has been reached or not. Since resonant circuits are used in inductive proximity switches, the measurement accuracy is greatly influenced by the quality of the resonant circuit, which in turn depends strongly on the accuracy of the structural elements and external influences. Therefore, measures requiring great effort are necessary to somewhat increase the accuracy of such measuring devices. Our aim with the present invention is to eliminate the above shortcomings, i.e. to create an improved solution with which the position of the movable parts of railway switches can be continuously measured and their current condition can be checked. The set task was solved by a device that detects the positions of movable parts of a railway switch, for example, the top rails, and is provided with at least one sensor for this purpose. The essence of the device according to the invention is that the sensor is designed as a distance sensor suitable for continuous measurement of distance. Furthermore, the output of the distance sensor is connected to a central electronic evaluation unit suitable for two types of evaluation, in which one evaluation is a distance evaluation, and the other evaluation, separate from this, is a check of the functionality of the distance sensor. By designing the sensor as a continuous distance sensor, the invention makes it possible to precisely monitor the positions of the movable tip rails over the entire adjustment path, which is a significant step forward compared to conventional measuring sensors that are only intended to determine the end state. An electronic circuit arrangement is used for signal evaluation, with which it can be easily determined by means of a function check - for example by providing a reference signal - whether the sensor is still in an acceptable operating condition and whether it provides correct measurement results. Continuous position determination takes place during distance evaluation, in which case the calculation of the current position of the switch tips can be considered as one possible method of position determination.For fast processing of existing measurement values ​​after analog-to-digital conversion, high-performance microcontrollers with fast clock speeds can be used, since the relationship between the position of the tip rail and the sensor signal is usually not linear. According to a further feature of the invention, it is expedient if the distance evaluation is connected to a characteristic curve query determined by the signal of the distance sensor as a function of the tip rail position. Thanks to such a characteristic curve query, the current position of the tip rail can be precisely determined. HU 225 355 B1 A further advantageous embodiment of the invention has at least one further sensor, the output of which is connected to the central electronic evaluation unit for measuring the rest signal in both end positions and is in cooperative connection with the function check. By using an additional distance sensor in this embodiment, which may be a specially calibrated sensor or the same as the first distance sensor, the accuracy of the measurement of the rest signal and thus the reliability of the function check is further improved. The position determination of the movable parts of the railway switch can be further refined by an embodiment of the device according to the invention which has at least two distance sensors. These are arranged on the track, for example in a common measuring plane, in the region of the end positions of the movable switch parts, especially the top rails, which are resting on the main rail and are remote from it. By arranging several distance sensors in the above-mentioned manner, in addition to the function check in the undamped state, an additional function check can also be carried out in the damped end position. By using at least two distance sensors arranged at different locations, the reliability of the function check and the accuracy of the distance measurement can be further improved by comparing the measured values ​​and / or averaging. Furthermore, in the case of such a design, deformations of the movable tip rails, e.g. due to wear, can be continuously monitored along the entire length of the switch, for which measurements can also be taken while the vehicle is passing over the switch. In this way, the actual operating condition of the switches can always be determined precisely and long-term changes can be calculated in advance. According to a further feature of the invention, the characteristic curves stored for the characteristic curve query are provided with tolerance fields for the permissible operating ranges for the positions of the movable parts, especially the top rails, in contact with and removed from the main rail, and the functionality is also checked in the contact and removed end positions. The tolerance fields prevent the function check from triggering an alarm signal even with a small displacement from the end position of the movable top rails and from interrupting the operation too early in cases that are not actually critical. This design also makes it possible to continuously monitor changes in end positions and to carry out repair and adjustment operations that occur too early, even when the measured values ​​are within the tolerance fields. This means that wear conditions within the tolerance limits can be clearly observed, which can save significant material and costs. It is advisable if the quiescent signal is connected to the characteristic curve query as a calibration value for the characteristic curve. Since the quiescent signal can be used to "shift" the characteristic curve itself, the value of the quiescent signal is equal to the function value of the shifted position, and a characteristic curve series is formed. Such a characteristic curve self-regulation during the formation of the characteristic curve series allows operating effects and aging phenomena to be largely eliminated during signal evaluation and genuine position values ​​to be determined. In order to eliminate further interference factors resulting from line losses, such as voltage drops due to line resistances, it is advisable to design the distance sensor outputs as current outputs. By designing the sensor outputs as current outputs, the sensor output signals are available as easily processed current signals. In order to reliably determine the operating trends of railway switches over a longer period of time, for example to detect wear in a timely manner and to determine the remaining service life of the switch in advance, it is advisable for the central electronic evaluation unit to be connected to a data storage device. In order to check the safe closure of the top rails when moving them and to check the narrowest passage, it is advisable to use an embodiment in which the distance sensors are arranged in different measuring planes. The method according to the invention is for evaluating the signals of sensors used for determining the position of movable parts of railway switches, for example point rails, in which the device according to the invention is preferably used. The essence of the method according to the invention is that the signals of the distance sensors are evaluated in a characteristic curve calculation unit, the positions are determined as functions of the signal values, in which case the signals are compared with the quiescent signals of the distance sensors and the operability of the distance sensors is determined. If appropriate, signal values ​​outside the tolerance fields specified in the characteristic curves are taken into account for error signals, and the characteristic curve is adapted to the operating conditions by comparing it with the quiescent signals of the distance sensors within the permissible tolerance range, and short-term error signals are suppressed. Since the signals emitted by the sensors are analyzed both for determining the distance and for testing the functionality of the sensors by simultaneously adjusting the characteristic curve, the interference effects on the equipment have been completely eliminated and the measurement accuracy has been greatly increased. Since only those signal values ​​trigger an error signal that fall outside the tolerance range predefined in the characteristic curve, the range within the tolerance fields is therefore considered the operating range. This ensures that operations are not interrupted in the event of small displacements of the top rails from the end position, since maintaining operation in such cases does not involve any risk. Such a measurement technique, taken as a whole, increases the service life of the movable top rails of railway switches. If, on the other hand, the signal emitted does not fall within the tolerance fields, then either the top rail has moved or the sensor has failed. HU 225 355 Β1 (The simultaneous occurrence of these two disturbances is excluded by the safety guidelines of the railway regulations.) If the equipment indicates an actual fault, the sensors must be tested separately. Therefore, by also determining the duration of the fault indication through data storage, it is possible to eliminate fault indications that may arise, for example, from people or animals unintentionally entering the range of the distance sensors for a short time. The operational capability of the railway switches is therefore not interrupted in such a case. The evaluation procedure also ensures that only actual failure or malfunction of the sensors causes the interruption of railway operations. In a preferred embodiment of the method according to the invention, in addition to checking the movable top rails, the operability of the switch setting device is also checked. This allows for even more reliable switch setting. By checking the switch setting device, it is achieved that faults that can be traced back to the switch setting device and are not related to wear and tear of the top rails due to use or other operational influences can be filtered out in time. In this way, the main sources of error that directly lead to the shutdown and repair of the railway switch can be monitored continuously and independently of each other. In a further preferred embodiment of the method according to the invention, the measurement signals obtained in different measurement planes are compared with each other. This allows the safe closure to be monitored and the narrowest passage to be ensured. The invention is described in more detail on the basis of the attached drawing, which shows an exemplary embodiment of the solution according to the invention. In the drawing: Figure 1 is a schematic top view of a railway switch equipped with the device according to the invention; Figure 2 is a schematic diagram of a device for determining the position of the movable parts of the gearbox; Figure 3 shows the circuit arrangement of the solution according to Figure 2 in more detail; Figure 4 shows a diagram illustrating the characteristic curves used as the basis for the characteristic curve query. Below we provide an explanation of some terms for the purpose of a clear interpretation of our description and claims, but we note that these are known to the person skilled in the art in international practice. Figure 4 illustrates the positions and displacements of the rail tongue as a function of the sensor signals as a "characteristic curve". It is obvious from Figure 4 that this function is not linear. The term “quiescent signal” refers to the constant base current of the sensor. The quiescent, i.e. constant base current, is the current of the sensor that can be measured when there is no object to be measured within the operating range of the inductive sensor; in this case, the oscillator of the inductive sensor is not damped, which results in the sensor current being maximum. The term “functional check” refers to checking the correct operation of the sensor. By "characteristic curve interrogation" we mean that according to the invention the signals emitted by the sensor are compared with the characteristic curves in order to determine whether the sensor is still functioning properly. For this purpose, we have provided separate structural units which "interrogate" the characteristic curves. The term “characteristic curve self-regulation” means that the characteristic curves must be constantly adapted, as the physical and physical characteristics of the sensors change over time, for example due to wear. The initial static reference signal of the sensor is used as a calibration value to adapt the characteristic curve of the sensor. If the sensor reference signal deviates from the previously stored value, a new characteristic curve is generated, starting from this new static reference signal. The originally recorded characteristic curve can no longer be used after a certain operating time of the sensor, so a new characteristic curve is generated - starting from the newly measured static reference signal. In this way, a series of characteristic curves is generated, which is called a “characteristic curve series”. The narrowest passage is denoted by the term "minimum distance", which means the minimum distance between the rail and the moving rail tongue, in the open position of the rail tongue. The term “damped sensor” means that inductive distance sensors are “damped” by the measured object, in this case the movable rail section. In other words, the oscillator of the inductive sensor is damped depending on the distance of the measured object from the sensor. "Characteristic curve calculation" means that the characteristic curve calculation operation is necessary to determine the distance of the tongue rails from the sensor, using the query of the characteristic curves. The definition of "adapting the characteristic curve to the operating conditions" refers to the characteristic that we have already explained above under the term "self-regulation of characteristic curves", i.e. the characteristic curve is adapted, i.e. adjusted, to changes in the physical and physical characteristics of the sensor, for example due to wear and tear during use. Figure 1 shows a railway switch, the movable top rails of which are indicated by reference numerals 1 and 2. The switch is provided with a known switch adjusting device 3, which is capable of moving the top rails 1 and 2 to predetermined positions. This switch is equipped with a control device according to the invention. A találmány szerinti berendezésnek az 1 és 2 csúcssínek folyamatos távolságérzékelésére induktív 4, 5, 6 és 7 távolságérzékelői vannak, amelyek a jelen esetben egyazon közös mérési síkban vannak elrendezve. A váltó fix tősínjeit az 1. ábrán 8 hivatkozási számmal jelöltük. Amint az 1. ábra vázlatos felülnézetéből kitűnik, minden vágányhelyzetet egy-egy távolságérzékelő „figyel”, nevezetesen az 5 távolságérzékelő a 8 tősínen felfekvő 1 csúcssínnel, a 4 távolságérzé4 HU 225 355 The riser Β1 is associated with the top rail 2 removed from the main rail 8. The two additional distance sensors 6 and 7 are not damped in the switching position shown in Figure 1. In such an arrangement, it can be ensured that the position of the resting top rail is detected by a distance sensor oriented towards the rail ridge, and the position of the removed top rail is detected by a distance sensor oriented towards the rail base. Since, according to our experimental experience, the top rail removed from the main rail has a significantly larger dimensional tolerance than the top rail resting on the main rail, a much larger measuring range can be used to measure the position of the top rail removed from the main rail than in the case of the top rail resting on the main rail. The distance sensor used for the smaller measuring range of the top rail resting on the main rail can have a significantly higher resolution, so much higher measuring accuracy can be achieved here. In the solution according to the invention, the continuous monitoring of the position of the movable top rails 1 and 2 was combined with the monitoring of the operability of the electromechanically or electrohydraulically operated shift adjustment device 3. In Figure 2, we only schematically indicate the tip rails 1 and 2 resting on the main rail 8 or in a position removed from it, and the distance sensors 4 and 5 damped according to the tip rail positions, as well as the undamped distance sensors 6 and 7, which, as mentioned above, are designed for continuous distance sensing. The distance sensors 4, 5, 6 and 7 used here are of a two-wire design, which means that the sensed signal is converted into a current signal proportional to the distance, which cannot be falsified by the wire resistance. The device according to the invention has a central electronic evaluation unit 10, which is connected to the distance sensors 4, 5, 6 and 7, and in which the signals given by the distance sensors 4, 5, 6 and 7 are further processed, and thereby the respective positions of the top rails 1 and 2 are precisely determined. Furthermore, the device according to the invention has safety relays 11, which are in control connection with the outputs of the central evaluation unit 10. In Figure 3, we have again schematically marked the distance sensors 4, 5, 6 and 7 suitable for continuous measurement, which are connected to the electronic unit 12, which is part of the central electronic evaluation unit 10 illustrated in Figure 2, as shown here. The output signals of the distance sensors 4, 5, 6 and 7 are therefore processed in the electronic unit 12. In the electronic unit 12, the incoming signals are fed to two microcontrollers 15 and 17, which are operated independently of each other, by interposing input protection circuits 13 and frequency filters 14. The microcontrollers 15 and 17 are interconnected to test and constantly monitor the functionality of the distance sensors 4, 5, 6 and 7. The safety relays 11 are controlled by outputs 16 via a circuit arrangement not described in detail below. The microcontrollers 15 and 17 perform the actual processing of the signals. These are equipped with an electronic characteristic curve calculation unit (not shown) which determines the respective distance of the movable top rails 1 and 2 by means of the stored characteristic curves. In Figure 4, we have illustrated the characteristic curves of the different positions of the peak rails as a function of the detected signals represented as current signals. A 4. ábrán 1A hivatkozási jellel jelölt jelleggörbe megfelel a távolságérzékelő alapjelleggörbéjének, nevezetesen az elmozdulás és az áram függvényének. A 2A és 3A hivatkozási jelekkel jelölt jelleggörbék ezzel szemben olyan függvényeknek felelnek meg, amelyek a távolságérzékelő bizonyos használata, azaz bizonyos mértékű elöregedése, kopása után lépnek fel, amikor is 18 nyíl irányába a 2A jelleggörbe lefelé eltolódik az 1A jelleggörbéhez képest. Megfelelő méréstechnikai intézkedésekkel, például a távolságérzékelőn függetlenül mért nyugalmi áram összehasonlítása révén, a jelleggörbék a 18 nyíl irányába az elöregedési, kopási folyamatnak megfelelő változások figyelembevételével megfelelően módosíthatók. By determining the quiescent current of the distance sensors in the undamped state in addition to checking their functionality, a tolerance field is determined in the end position regions within the characteristic curve series, namely a tolerance field in the contact region and a tolerance field in the region of the removed top rail, thereby the operating state of the distance sensors 4, 5, 6 and 7 can be constantly monitored in both the damped and undamped states. The current signals detected after the switch changeover must be within the specified tolerance range for fault-free operation. If this signal falls outside the tolerance range, the fault can be traced back either to the impermissible position of top rail 1 or 2, or to the failure of the given distance sensor. According to practical experience, both disturbances can hardly occur simultaneously. Returning to Figure 1, in the second measurement plane, which is in this case offset from the first measurement plane, additional distance sensors 21 and 22 were arranged on both sides next to the top rails 1 and 2 and the main rails 8. These can of course also be connected to the central electronic evaluation unit 10, and their use further increases the measurement accuracy.

Claims

1. Device for determining the positions of movable railway switch parts, for example point rails, with at least one sensor, characterized in that the sensor is designed as a distance sensor (4, 5, 6, 7) suitable for continuous distance measurement, and furthermore the output of the distance sensor (4, 5, 6, 7) is connected to a central electronic evaluation unit (10) suitable for two types of evaluation, in which one evaluation is a distance evaluation and the other evaluation is a check of the functionality of the distance sensor (4, 5, 6, 7).

2. The device according to claim 1, characterized in that the evaluation unit (10) is designed to perform the distance evaluation as a function of the top rail position in association with a characteristic curve query determined by the signal of the distance sensor (4, 5, 6, 7).

3. Device according to claim 1 or 2, characterized in that it has at least one further distance sensor (5-7), the output of which is connected to the central evaluation unit (10) for measuring the idle setpoint in both end positions and is in a cooperative connection with the function monitor.

4. The device according to any one of claims 1-3, characterized in that it has at least two distance sensors (4-7), which are arranged in a common measurement plane on the track in the region of the end positions of the movable switch parts, especially the tip rails (1, 2), which are resting on the main rail (8) of the railway track and are remote from it.

5. Device according to any one of claims 1-4, characterized in that the characteristic curves (1 A, 2A, 3A) stored for the characteristic curve query have tolerance fields (19, 20) for the permissible operating ranges for the end positions of the movable parts, especially the top rails (1, 2), in contact and removed, and furthermore the device is designed to be able to perform the function check in these contact and removed positions.

6. The device according to any one of claims 1-5, characterized in that the quiescent signal is a calibration value belonging to the characteristic curve (1 A) which is associated with the characteristic curve query.

7. Device according to any one of claims 1-6, characterized in that the outputs of the distance sensor (4, 5, 6, 7) are designed as current outputs.

8. Device according to any one of claims 1-7, characterized in that the central electronic evaluation unit (10) is connected to a data storage device.

9. Device according to any one of claims 1-8, characterized in that the distance sensors (4, 5, 6, 7; 21, 22) are arranged in different measurement planes.

10. Method for evaluating the signals of sensors used to determine the position of movable railway switch parts, characterized in that the signals of the distance sensors (4-7) are evaluated in a characteristic curve calculation unit, the positions are determined as functions of the signal values, in which case the signals are compared with the quiescent signals of the distance sensors (4-7) and the operability of the distance sensors is determined, and if appropriate, signal values ​​outside the tolerance fields (19, 20) defined in the characteristic curves (1A, 2A, 3A) are taken into account for error signals, and the characteristic curve (2A, 3A) is adapted to the operating conditions by comparing it with the quiescent signals of the distance sensors (4-7) within the permissible tolerance range, and short-term error signals are suppressed.

11. The method according to claim 10, characterized in that in addition to checking the movable top rails (1, 2), the operability of the switch adjustment device (3) is also checked, 12. Method according to claim 10 or 11, characterized in that the measurement signals obtained in different measurement planes are compared with each other.