Rail vehicle and method for capturing track position data

Abstract

The invention relates to a rail vehicle (1) having a vehicle frame (2) which is movable on rails (5) of a track (4) in a manner supported on bogies (3), comprising a measurement platform (9) with a first inertial measurement system (13) for capturing track position data. The same measurement platform (9) has an associated second inertial measurement system (13) for measuring a movement of the measurement platform (9), the two inertial measurement systems (13) being coupled to a computer (17) and an algorithm for evaluating captured track position data being set up in the computer (17). Additional measured values are therefore available for calculating the track position data.

Description

Description Rail vehicle and method for recording track position data Technical field

[0001] The invention relates to a rail vehicle with a vehicle frame that is supported on rail bogies and is movable on the rails of a track, comprising a measuring platform with a first inertial measurement system for acquiring first track position data. The invention further relates to a method for operating such a rail vehicle. State of the art

[0002] A rail vehicle equipped with an inertial measurement system for acquiring track geometry data is known, for example, from AT 523627 A4. During a measurement run, data from a trajectory are acquired using an inertial measurement unit (IMU). Relative movements of the IMU with respect to the track are compensated for by means of position measuring devices. As a result, the inertial measurement system provides actual track geometry data, which is used to calculate the target geometry of the track.

[0003] From AT 520526 A4, a rail vehicle is known in which a first measuring platform is arranged on a rail bogie. A track alignment is recorded by means of an inertial measurement system mounted on the first measuring platform. A second measuring platform with a second inertial measurement system and a sensor device for detecting surface points along a track is arranged on the car body of the rail vehicle. The second inertial measurement system detects the movement of the sensor device in three-dimensional space. Description of the invention

[0004] The invention is based on the objective of improving a rail vehicle of the type mentioned at the outset in such a way that the acquisition of track position data can be carried out with higher quality, in particular with higher Process reliability and feasibility must be ensured. Furthermore, a suitable procedure should be specified.

[0005] According to the invention, these problems are solved by the features of independent claims 1 and 9. Dependent claims specify advantageous embodiments of the invention.

[0006] In this system, a second inertial measurement system is assigned to the same measuring platform to measure its movement. Both inertial measurement systems are coupled to a computer, which contains an algorithm for evaluating the acquired track geometry data. Specifically, in each inertial measurement system, an inertial measurement unit (IMU) records the movement of the measuring platform in free space using three accelerometers and three gyrocompasses. The measuring platform is a rigid component of the rail vehicle. Due to the fixed arrangement of the inertial measurement units of both systems on the same rigid measuring platform, the platform's movement is recorded twice. This provides additional measurement data for acquiring and calculating the track geometry data. Furthermore, the acquired measurement data can be used for mutual verification.On the other hand, with appropriate arrangement of the inertial measuring units, additional information for calculating track geometry data can be obtained from the resulting trajectories. Precise track geometry data is derived directly from the respective trajectory when the measuring platform is guided along the track with flanged wheels pressed against a rail. Otherwise, the respective trajectory is at least an approximation of the track alignment, with deviations optionally detectable and compensable. Acquiring approximate track geometry data is sufficient for some applications.

[0007] In an advantageous advanced configuration, each inertial measurement system is set up for the separate acquisition of track geometry data. Both inertial measurement systems measure the track geometry in accordance with regulations, for example, according to standard EN 13848-2. With the two inertial measurement systems integrated into a single overall system, the track geometry is recorded redundantly. The entire system performs fully autonomous and recurring self-checks. Measurement errors are automatically detected and immediately corrected. In this way, the redundantly available track position data leads to higher process reliability.

[0008] Preferably, the measuring platform is arranged on one of the rail bogies, in particular as a measuring frame connected to the wheel axles. This minimizes relative movements of the measuring platform with respect to the track. With a measuring frame connected to the wheel axles, only pendulum movements of the wheels relative to the rails need to be considered. Apart from this, the trajectories recorded by the inertial measuring units correspond to the track alignment.

[0009] In an advantageous embodiment, at least one track measurement unit is arranged on the measuring platform to detect the position of the measuring platform relative to at least one rail of the track. This allows any relative movements between the measuring platform and the rail in the transverse direction to the track axis to be detected. For example, the track measurement unit is designed as a light section sensor and directed towards the inner edge of the rail head. The exact path of this inner rail edge can then be derived from the trajectories detected by the two inertial measuring units.

[0010] A further improvement enables the precise measurement of both rail alignments by arranging a front track gauge measuring system and a rear track gauge measuring system, spaced apart from it in the longitudinal direction of the vehicle, on the measuring platform. This allows the position of the measuring platform relative to both rails of the track to be determined when stationary, at low speeds, and at high speeds. Furthermore, the track gauge can be measured separately with each of the track gauge measuring systems.

[0011] Advantageously, different algorithms for processing motion data are implemented in the first and second inertial measurement systems. This increases functional safety, thereby achieving higher Safety Integrity Levels (SILs). High overall accuracy is achieved when the results obtained with both algorithms lie within a narrow tolerance range. Corresponding accuracy requirements are defined in the standard EN 13848-2.

[0012] Furthermore, functional safety is increased if the first and second inertial measurement systems comprise different hardware components, particularly different inertial measurement units. This ensures that any inherent system errors can be detected and corrected immediately.

[0013] To record the distance traveled by a rail vehicle, an odometer is advantageously mounted on a wheel axle. The data acquired by the inertial measurement systems are evaluated together with the measured distance. Furthermore, several track gauge measuring systems arranged in series can be used for distance measurement. This utilizes slight variations in the track gauge. Every point on the track exhibits a characteristic track gauge profile in its surroundings. Thus, the measurement of the track gauge profile allows conclusions to be drawn about the corresponding point on the track and, consequently, the distance traveled. This use of track gauge measuring systems can also be employed to verify the distance measured by the odometer. This, in turn, increases functional safety because the distance is recorded by two independent systems that function differently from one another.

[0014] In the inventive method for operating the described rail vehicle, the movement of the measuring platform is measured using both inertial measurement systems, track position data is derived from the measured movement, and the track position data is evaluated using the algorithm configured in the computer. The dual movement measurement of the same measuring platform increases the overall accuracy and process reliability.

[0015] Advantageously, the first inertial measurement system acquires initial track position data, and the second inertial measurement system acquires secondary track position data, wherein, in particular, longitudinal height data, swept height data, twist data, superelevation data, and track gauge data are acquired as the respective track position data. In this embodiment of the invention, each of the two inertial measurement systems initially acquires The track position data is collected independently of each other inertial measurement system. Only then is a joint evaluation carried out using a computer.

[0016] In a preferred advanced training, the algorithm compares at least a selection of first track position data with a corresponding selection of second track position data, generating an error message if a difference between the compared track position data reaches a tolerance limit. This continuous integrity check ensures a high level of functional safety.

[0017] Recording error messages in a digital measurement log is advantageous. Such a log ensures that measurements performed with inertial measurement systems remain traceable. Digital error recording enables automated processing of the measurement results, allowing recurring errors to be identified and compensated for using a machine learning algorithm.

[0018] In a further improvement of the method, positional data of the measuring platform relative to at least one rail of the track is recorded using a track measuring unit arranged on the measuring platform. This allows relative movements of the measuring platform relative to the rail in the transverse direction of the track to be easily compensated.

[0019] In a preferred further development, the first track position data is calculated based on the position data using an evaluation unit assigned to the first inertial measurement system, and the second track position data is calculated using an evaluation unit assigned to the second inertial measurement system. Each inertial measurement system is thus configured for the separate acquisition of the track position data, whereby relative movements of the measuring platform with respect to the track are compensated for using the same position data.

[0020] Advantageously, the position of the measuring platform is determined by means of a front and a rear track gauge measuring system, whereby the track gauge data obtained is compared with track gauge data from another track gauge measuring system mounted on the rail vehicle. In addition to the precise position determination of the measuring platform, this process improvement enables redundant path measurement based on the characteristic track gauge profile. This increases measurement accuracy and process reliability. Brief description of the drawings

[0021] The invention is explained below by way of example with reference to the accompanying figures. These show, in schematic representation: Fig. 1 Rail vehicle on a track in side view Fig. 2 Rail vehicle on a track in oblique view Fig. 3 Cross-section of a rail vehicle on a track. Fig. 4 Track measurement with two gauge measuring systems. Description of the embodiments

[0022] The rail vehicle 1 shown in Fig. 1 comprises a vehicle frame 2 which is movable on rail bogies 3 on a track 4. The track 4 comprises two rails 5 which are fastened to sleepers 7 supported in a ballast bed 6. The invention also relates to a slab track (not shown) in which the rails 5 are fastened to a fixed superstructure made of concrete. The rail vehicle 1 is, for example, a measuring vehicle or a track construction machine with a working unit 8 for track maintenance.

[0023] The depicted rail vehicle 1 comprises several measuring platforms 9, which are movable relative to each other. For example, an optical measuring system 10 for detecting surface points of the track 4 is mounted on one of the measuring platforms 9 in the front area. Between the rail bogies 3 is another measuring platform 9 with track gauge measuring systems 11 mounted on it, each comprising track gauge measuring units 12 directed towards the rails 5. The respective track gauge measuring unit 12 is, for example, a light section sensor that detects the position of the measuring platform 9 relative to the associated rail 5.

[0024] Furthermore, a measuring platform 9, designed as a measuring frame, is arranged on one of the rail bogies 3. Relative movements between this measuring platform 9 and the other measuring platforms 9 result from the suspension, steering, and tilting of the rail bogie 3. in relation to the vehicle frame 2. A first and a second inertial measurement system 13 are assigned to the rigid measuring frame. At least the inertial measurement units 14 of the two inertial measurement systems 13 are fixed in their relative positions on the measuring platform 9. The term inertial measurement unit (IMU) refers to the actual measuring instrument for measuring angular rate and acceleration. The respective inertial measurement system 13 is also capable of executing correction algorithms and determining the position. Usually, the measuring instrument and a microcontroller 20 are housed in a common enclosure. However, the components can also be distributed across several enclosures.

[0025] A trajectory 15 of the associated inertial measurement unit 14 can be derived from the motion data acquired by the respective inertial measurement system 13. A coordinate system with its origin at the starting position of a measurement run typically serves as the reference system. As soon as the rail vehicle 1 starts moving, position points 15 are recorded along the two trajectories, the coordinates of which are subsequently available for evaluation.

[0026] The distance traveled is recorded, for example, by means of an odometer 16. Alternatively or additionally, the track gauge measuring systems 11 are used for distance measurement. During a forward movement of the rail vehicle 1, each track gauge measuring system 11 records a profile of the track gauge g over a travel time t, as shown in Fig. 4. Because both track gauge measuring systems 11 measure the same track 4 immediately one after the other, two approximately identical track gauge profiles result with a time offset At. This time offset At is evaluated, whereby the current speed and the distance traveled can be determined with a fixed distance a between the track gauge measuring systems 9. In this way, the track gauge measuring systems 11 are used for distance measurement in addition to position and track gauge measurement.

[0027] Furthermore, the repeated track gauge measurement increases process reliability. For this purpose, the track gauge measuring systems 11 are coupled to a computer 17. The computer 17 continuously compares the input parameters in the form of the track gauges. The following are compared: For example, the measurement results of a first group of track gauge measuring systems 11 arranged on the vehicle frame 2 are compared with the measurement results of a second group of track gauge measuring systems 11 arranged on the rail bogie 3. The latter are coupled with the inertial measuring systems 13. From the measurement results of the first group, for example, an average value is calculated, which is continuously compared with a current measurement value of the second group using a known longitudinal offset b. If deviations are too large, an error message is generated.

[0028] Both inertial measurement systems 13 are also coupled to the computer 17. The acquired track position data is evaluated using an algorithm configured in computer 17, which also verifies data integrity. In the simplest case, the data acquired by the inertial measurement systems 13 are continuously compared. As soon as a difference reaches a tolerance limit, an error message is generated. This is useful if the inertial measurement units 14 are arranged directly next to each other on the measurement platform 9. In this case, it can be assumed that the same motion data are acquired synchronously during error-free operation. Such an arrangement is shown in Fig. 2, where, for better visibility of the individual components, the car body of the rail vehicle 1 is shown separated from the track bogies 3.

[0029] Advantageously, the two inertial measurement systems 13 differ in their installed hardware components. To further increase process reliability, the two inertial measurement systems 13 also differ in the algorithms and filters used to process the motion data. Using different systems for acquiring and processing the motion data increases the safety integrity level. This requirement is met, for example, by using inertial measurement systems 13 from different manufacturers.

[0030] Furthermore, it is possible to automatically calibrate the two inertial measurement systems 13 by continuously comparing the measurement results. This compensates for drift that typically occurs with inertial measurement units 14.

[0031] Additional information is obtained by spaced-apart arrangements of the inertial measuring units 14 on the measuring platform 9. In the example shown in Fig. 1, the first inertial measuring unit 14 is arranged on a front crossbeam of the measuring frame, and the second inertial measuring unit 14 is arranged on a rear crossbeam of the measuring frame. In this way, the movement of the measuring platform 9 in space is recorded at different locations. The forward movement of the rail vehicle 1 can be derived from the resulting motion data.

[0032] The position of the measuring frame relative to the rails 5 is determined by the track gauge measuring systems 11 arranged at the front and rear of the measuring frame. Fig. 3 shows one of these track gauge measuring systems 11 with two track gauge measuring units 12. In each track gauge measuring unit 12, a laser source 18 projects a fan of light onto the associated rail 5. The resulting projection on the rail 5 is captured by a camera 19 and evaluated in a microcontroller 20. In this way, the position of the track gauge measuring unit 12 relative to the associated rail 5 is determined. All four track gauge measuring units 12 arranged on the measuring frame provide position data of the measuring frame relative to the rails 5.

[0033] In an evaluation unit 21, the position data acquired by the track gauge measuring systems 11 are used to deduce the track position from the respective trajectory 15. The coordinates of the respective trajectory 15 are transformed onto the respective rail 5 via the known geometric arrangement of the inertial measuring units 14 and the track gauge measuring units 12 relative to each other. This subsequently yields the relevant track parameters, in particular the track gauge, the direction or swept height, the longitudinal height, the superelevation, and the twist of the track 4. Advantageously, each inertial measuring system 13 is assigned its own evaluation unit 21. The track position data, acquired twice, are then evaluated in the computer 17 and their integrity is checked.

[0034] Combining the measurement data increases the overall accuracy. Errors are detected immediately and taken into account during further processing of the track geometry data. This is achieved, for example, by... Stochastic comparisons of the track parameters determined by the different individual measuring systems are performed. Statistical evaluations can compensate for measurement inaccuracies and eliminate localized measurement errors. The standard EN 13848-2 defines the required accuracy. For each individual measuring system, 95% of the measurement results must lie within the specified tolerance. The inventive redundancy of the individual measuring systems results in a higher overall accuracy, with up to 99% of the combined measurement results lying within the tolerance.

Claims

Patent claims 1. Rail vehicle (1) with a vehicle frame (2) supported on rail bogies (3) and movable on rails (5) of a track (4), comprising a measuring platform (9) with a first inertial measuring system (13) for recording track position data, characterized in that a second inertial measuring system (13) for measuring a movement of the measuring platform (9) is assigned to the same measuring platform (9), that both inertial measuring systems (13) are coupled to a computer (17) and that an algorithm for evaluating recorded track position data is set up in the computer (17).

2. Rail vehicle (1) according to claim 1, characterized in that each inertial measurement system (13) is equipped for the separate acquisition of track position data.

3. Rail vehicle (1) according to claim 1 or 2, characterized in that the measuring platform (9) is arranged on one of the rail bogies (3), in particular as a measuring frame connected to wheel axles.

4. Rail vehicle (1) according to one of claims 1 to 3, characterized in that at least one track measuring unit (12) for detecting the position of the measuring platform (9) relative to at least one rail (5) of the track (4) is arranged on the measuring platform (9).

5. Rail vehicle (1) according to one of claims 1 to 4, characterized in that a front track gauge measuring system (11) and a rear track gauge measuring system (11) spaced apart from it in the longitudinal direction of the vehicle are arranged on the measuring platform (9).

6. Rail vehicle (1) according to one of claims 1 to 5, characterized in that different algorithms for processing motion data are provided in the first inertial measurement system (13) and in the second inertial measurement system (13).

7. Rail vehicle (1) according to one of claims 1 to 6, characterized in that the first inertial measuring system (13) and the second inertial measuring system (13) comprise different hardware components, in particular different inertial measuring units (14).

8. Rail vehicle (1) according to one of claims 1 to 7, characterized in that an odometer (16) for recording a distance is arranged on a wheel axle of the rail vehicle (3).

9. Method for operating a rail vehicle (1) according to one of claims 1 to 8, characterized in that a movement of the measuring platform (9) is measured by means of both inertial measuring systems (13), that track position data are derived from the measured movement and that the track position data are evaluated by means of the algorithm set up in the computer (17).

10. Method according to claim 9, characterized in that first track position data are acquired by means of the first inertial measuring system (13) and second track position data are acquired by means of the second inertial measuring system (13) and that in particular longitudinal height data, swept height data, twist data, superelevation data and track gauge data are acquired as respective track position data.

11. Method according to claim 10, characterized in that at least a selection of first track position data is compared with a corresponding selection of second track position data by means of the algorithm and that an error message is generated if a difference between the compared track position data reaches a tolerance limit.

12. Method according to claim 11, characterized in that the error message is recorded in a digital measurement protocol.

13. Method according to one of claims 9 to 12, characterized in that a track measuring unit (12) arranged on the measuring platform (9) is used. Position data of the measuring platform (9) relative to at least one rail (5) of the track (4) are recorded.

14. Method according to claim 13, characterized in that the first track position data are calculated on the basis of the position data by means of an evaluation device (21) assigned to the first inertial measuring system (13) and the second track position data are calculated by means of an evaluation device (21) assigned to the second inertial measuring system (13).

15. Method according to one of claims 9 to 14, characterized in that the position of the measuring platform (9) is detected by means of a front track gauge measuring system (11) and a rear track gauge measuring system (11) and that track gauge data detected thereby are compared with track gauge data of a further track gauge measuring system (11) arranged on the rail vehicle (1).

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