Method and device for inspecting track

Abstract

The invention relates to a method for contactlessly detecting the position of an inspection device (2) movable on a track (8) via a rail travelling device (3) relative to at least one rail (9) of the track (8), in which a projection (17) of a laser beam (15) projected onto the at least one rail (9) is detected by means of a camera (11), in which the projection (17) is projected onto the rail (9) and onto an inner surface (18) of a wheel (19) of the rail travelling device (3) and the detected position of the inspection device (2) relative to the inner surface (18) of the wheel is evaluated by means of an evaluation device (21). The method utilizes the inner surface (18) of the wheel disc as a reference for determining at least one position value of the inspection device (2).

Description

[Technical field]

[0001] The present invention relates to a method for contactlessly detecting the position of an inspection device movable on a track via a rail traveling device relative to at least one rail of the track, in which a projection of a laser beam projected onto the at least one rail is detected by means of a camera, and further to an apparatus configured to perform this method. [Background technology]

[0002] Measurements are carried out at regular intervals in order to be able to assess the state of the track, the wear phenomena and displacements detected forming the basis for planning and carrying out necessary maintenance measures.

[0003] Mostly, inspection devices are used that are arranged on the rail vehicle and thus can move along the track. Special track inspection vehicles have a number of inspection devices whose measurement results are combined into one overall picture of the track condition. In this case, it is necessary to accurately determine the position of each inspection device relative to at least one rail of the track so that absolute or relative track positions or wear phenomena can be derived. Corresponding inspection devices are also used to determine the gauge or gauge line, in which case the position relative to both rails is evaluated.

[0004] Corresponding inspection devices known from Austrian Utility Model No. 14280 and German Publication No. 1165064 work with laser technology, camera systems or ultrasound. Oberlechner G. et al.: POS / TG-Innovation auf dem Gebiet der Gleisgeometriemessung, EI-Eisenbahningenieur (52) 9 / 2001, pp. 6-9, describe further devices for track inspection. Such contactless designs are not subject to wear. However, they place high demands on the control and evaluation devices. In particular, these inspection devices require a calibration process in order to be able to determine the position relative to a reference standard during readjustment. Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the invention is to improve a method of the type mentioned at the outset in order to increase the degree of automation. Furthermore, a corresponding device should be provided. [Means for solving the problem]

[0006] According to the invention, this problem is solved by a method according to claim 1 and by a device according to claim 6. Advantageous configurations of the invention are described in the dependent claims.

[0007] In this case, projections are projected onto the rail and onto the inner surface of the wheel of the rail-running device, and the position of the measuring device relative to the inner surface of the wheel detected is evaluated by means of an evaluation device. The method uses the inner surface of the wheel disc as a reference standard for determining at least one position value of the measuring device. In addition to the distance between the measuring device and the wheel, the mounting angle of the measuring device can also be detected, in particular based on the known orientation of the inner surface of the wheel. The rate of change of the inner surface of the wheel that may possibly occur is very small and may possibly be measured together during continuous operation. This self-monitoring of the measuring system avoids erroneous detection of the position relative to the correspondingly arranged rail.

[0008] In one refinement of the method, in order to automatically calibrate the measuring device, the position of the measuring device relative to the inner surface of the wheel is detected and the detected distance and / or angle of the measuring device relative to the inner surface of the wheel is compared with stored values ​​by means of an evaluation device. With the aid of this self-calibration process, the measuring device itself determines its spatial position. This is particularly useful after a sensor exchange or readjustment of the measuring device.

[0009] Advantageously, two coupled measuring devices are used to detect the position of the track relative to both rails and thereby determine the track gauge, whereby each measuring device determines its own position relative to the correspondingly arranged wheel disc, and the resulting offset dimensions are used as a basis for deriving all the gauges.

[0010] In one refinement of the method, the position of each of the two measuring devices is detected relative to the inner surface of the correspondingly arranged wheel, and the evaluation device is used to compare the detected distance and / or angle of each of the measuring devices relative to the inner surface of the correspondingly arranged wheel with stored values. The orientation of each of the wheels arranged on one common axle is empirically always constant. Since any possible differences over time are negligibly small, a permanent reference standard is provided together with the inner surface of the wheel pair.

[0011] In the above-mentioned automatic calibration method, it is advantageous if an automatic recalibration of the detected distance and / or angle is carried out at predefined time intervals. This ensures that no inaccuracies arise as a result of possible drifts. The computational power required for this remains low, since the individual calibration processes are carried out at sufficiently long time intervals.

[0012] The device according to the invention for contactlessly detecting the position of an inspection device relative to the rails of a track comprises an inspection device and a rail travelling device which is coupled to the inspection device and can travel on the track, the inspection device comprises a laser device for projecting a laser beam and a camera for detecting the projection and is directed towards the rail travelling device in such a way that the laser beam can be projected both onto the rail and onto the inner surface of the wheels of the rail travelling device, and an evaluation device is arranged for evaluating the detected position of the inspection device relative to the inner surface of the wheels. As the inspection device, preferably known light section sensors (laser scanner, mirror scanner) for optically detecting the surface are used. What is novel is the arrangement of the inspection device and the evaluation device which is arranged to determine the position of the inspection device relative to the inner surface of the wheels.

[0013] In one preferred refinement of the device, the detection device comprises a closed casing with at least one viewing window for the laser beam and for the detection range of the camera, whereby the sensor system of the detection device is shielded against adverse influences of the surrounding environment, in particular against moisture, dust and solar radiation.

[0014] In one further refinement, at least one inspection device is arranged on one common inspection frame for each rail of the track, the common inspection frame forming a rigid base for the inspection devices, so that their positions relative to one another remain unchanged.

[0015] Advantageously, an inertial measurement unit (IMU) is arranged on the measuring frame for determining the trajectory. With this extension, in addition to the position and the gauge of the rail relative to the measuring unit, the extension of the rail can also be determined. In this case, the trajectory of each rail is derived from the trajectory determined by the inertial measurement unit via the measurement results of each measuring device.

[0016] One further refinement envisages that the evaluation device is provided with an automatic calibration routine by means of which the distance and / or angle of each detected measuring device relative to the inner surface of the correspondingly positioned wheel can be compared with stored values, said automatic calibration enabling the device to operate with a sufficiently accurate measuring accuracy even after being adversely affected.

[0017] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing a railway vehicle. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] In Fig. 1, a rail vehicle with an inspection platform as device 1 is shown, on which four inspection devices 2 are arranged. An inspection frame 4 arranged on a rail running device 3 is used as the inspection platform. In one alternative configuration, a vehicle frame 5 is used as the inspection platform. The rail vehicle is, for example, a track inspection vehicle with a number of further inspection devices (e.g. ultrasonic inspection devices for inspecting the rail material, rotating lasers, etc.). In particular, an inertial measurement unit 6 is arranged on the inspection frame 4, which detects a trajectory 7.

[0020] In one reduced configuration (not shown), the device 1 is a manual inspection vehicle with a rail travelling device 3 and at least one inspection device 2. During the inspection process, the inspection device 2 coupled to the rail travelling device 3 is moved along the track 8. In this case, the inspection device 2 is used to measure the position of the track 8 relative to at least one rail 9. In the illustrated example, four inspection devices 2 are arranged on a common rigid inspection frame 4. Thereby, the exact positions of all inspection devices 2 relative to the rails 9 of the track 8 are detected.

[0021] Each inspection device 2 is configured as a light section sensor and includes a laser device 10, a camera 11 and a control device 12. In the illustrated embodiment, the laser device 10 includes a laser source 13 and a deflection mirror 14. The laser device 10 projects a fan-shaped laser beam 15 onto the inner rail head edge 16 of the rail 9. In particular, the laser source 13 is configured as a so-called line laser. In this case, a line projection 17 instead of a point is generated by special optics, in which case various geometric shapes are possible. In the context of the invention, simple line segments, rectangles or triangles are of value as the line projection 17, for example.

[0022] In the present invention, the projection 17 is not only projected onto the rail 9, but also onto the inner surface 18 of the wheel 19 of the rail traveling device 3. The part projected onto the inner surface 18 of the wheel is detected by means of the camera 11. For this purpose, the detection range 20 of the camera 11 is directed towards both the rail 9 and the inner surface 18 of the wheel. On the basis of the detected image data, the position of the inspection device 2 with respect to the inner surface 18 of the wheel is determined in an evaluation device 21 by means of photogrammetry.

[0023] For example, the control device 12 and the evaluation device 21 are combined and arranged with a powerful microprocessor in the measuring device 2 itself. However, the evaluation device 21 can also be installed in a separate computing unit 22 in the rail vehicle. In the offline version, the recorded data is stored on a data storage medium. The data is then centrally evaluated in the evaluation device 21. In this case, the data is preferably linked to the respective position coordinates, which are determined, for example, by means of a GNSS system or a distance sensor.

[0024] In one alternative embodiment, the inspection data is transmitted centrally via an air interface and evaluated there. Position or gauge data already evaluated in real time is also transmitted centrally and can be used for maintenance planning.

[0025] To utilize further aspects of the invention, the inspection device 2 can be integrated into the inspection system of a railway construction machine, in which case the inspection data can be used directly for various maintenance measures, for example to inspect or re-inspect the track during tamping or cleaning operations.

[0026] FIG. 2 shows the arrangement of the laser devices 10 and the cameras 11 of the individual inspection devices 2 relative to the wheels 19 of the correspondingly arranged rail travelling devices 3. The laser source 13 projects a projection 17 via a deflection mirror 14 onto the inner rail head edge 16 and simultaneously onto the inner surface 18 of the wheel 19. In this example, the part projected onto the wheel 19 is a straight line. In the inspection device 2, a zero point 23 and a coordinate system xyz are defined. Furthermore, the inner surface 18 of the wheel 19 is a plane, in which the projected straight line is located. This relationship makes it possible to determine the normal distance a between the zero point 23 and the inner surface 18 of the wheel 19 by means of photogrammetry in the evaluation device 21. Furthermore, the angle α, which indicates the inclination of the inspection device 2 relative to the inner surface 18, can be determined. For example, the angle α includes the coordinate axis z and the normal to the inner surface 18.

[0027] An exemplary calibration method is described in connection with Fig. 3. Here, one measuring device 2 is assigned to each rail 9. With the above-described measuring method, the distances a1, a2 to the inner surface 18 of the wheel assigned to it are measured for each measuring device 2. The mutual distance c of the measuring devices 2 is obtained via the known and constant inner distance b of the wheel discs 19. In this way, each measuring device 2 can be calibrated anew after a sensor exchange or after a mounting adaptation. Furthermore, a recalibration can be carried out at any time.

[0028] By evaluating the projection 17 on the rail head inner edge 16, the gauge s of the track 8 can subsequently be determined using the mutual spacing c of the inspection devices 2. Methods for determining the position of a light section sensor relative to the rail head inner edge 16 are known, for example, from AU 520 266 A1.

[0029] In Fig. 4 an exemplary device 1 is shown in plan view. On each rail 9, two inspection devices 2 are arranged corresponding to each other at a fixed distance d. Each inspection device 2 comprises a dedicated laser device 10, which projects a projection 17 onto the correspondingly arranged rail 9 and onto the inner surface 18 of the correspondingly arranged wheel. This allows the position of each inspection device 2 to be calibrated separately. All inspection devices 2 are arranged on a common inspection frame 4, which is directly connected to the axles 24 of the wheels 19 of the rail travelling device 3. This means that the spring travel of the rail travelling device 3 does not influence the position of the inspection frame 4 relative to the rail 9. The inspection frame 4 can thus be used as a reference surface for track inspection.

[0030] The gauge s is measured simultaneously at two points within the distance d by this device 1. This allows the extension of the rails 9 to be detected starting from a standstill and at low forward speeds without detection of the trajectory 7. From a minimum speed onwards, the trajectory 7 detected by means of the inertial measuring unit 6 can be transferred to each rail 9 via the measured values ​​detected by means of the measuring device 2.

[0031] The rail travelling device 3 applies a load to the track 8 during the inspection run. Thus, track inspection is performed under realistic load conditions. No compensation of the spring travel or movements of the carbody 25 is required.

Claims

1. 1. A method for contactlessly detecting the position of an inspection device (2) movable on a track (8) via a rail traveling device (3) relative to at least one rail (9) of the track (8), the method comprising detecting a projection (17) of a laser beam (15) projected onto the at least one rail (9) using a camera (11), characterized in that the projection (17) is projected onto the rail (9) and onto an inner surface (18) of a wheel (19) of the rail traveling device (3), and the detected position of the inspection device (2) relative to the inner surface (18) of the wheel is evaluated using an evaluation device (21).

2. 2. The method according to claim 1, further comprising detecting a position of the measuring device (2) relative to the inner surface (18) of the wheel (19) and comparing the detected distance (a) and / or angle (α) of the measuring device (2) relative to the inner surface (18) of the wheel (19) with stored values ​​(b) by means of the evaluation device (21) in order to automatically calibrate the measuring device (2).

3. 3. The method according to claim 1, wherein two coupled measuring devices (2) are used to detect the position of the track (8) relative to both rails (9) and determine the gauge (s) of the track (8) therefrom.

4. 4. The method according to claim 3, wherein the automatic calibration of the two measuring devices (2) comprises detecting the position of each of the measuring devices (2) relative to the inner surface (18) of the correspondingly arranged wheel (19) and comparing the detected distance (a) and / or angle (α) of each of the measuring devices (2) relative to the inner surface (18) of the correspondingly arranged wheel (19) with stored values ​​(b) by means of the evaluation device (21).

5. 3. The method according to claim 2, wherein an automatic recalibration of the detected distance (a) and / or angle (α) is carried out at predetermined time intervals.

6. 1. A device (1) for contactlessly detecting the position of an inspection device (2) relative to a rail (9) of a track (8), the inspection device (2) being coupled to a rail traveling device (3) capable of traveling on the track (8) and including a laser device (10) for projecting a laser beam (15) and a camera (11) for detecting the projection (17), characterized in that the inspection device (2) is oriented with respect to the rail traveling device (3) so that the laser beam (15) can be projected onto both the rail (9) and an inner surface (18) of a wheel (19) of the rail traveling device (3), and an evaluation device (21) is disposed in the device (1) for evaluating the detected position of the inspection device (2) relative to the inner surface (18) of the wheel.

7. 7. The device (1) according to claim 6, wherein the inspection device (2) comprises a closed casing with at least one viewing window for the laser beam (15) and for the detection range (20) of the camera (11).

8. 8. Apparatus (1) according to claim 6 or 7, characterized in that at least one inspection device (2) is arranged on one common inspection frame (4) for each rail (9) of the track (8).

9. 9. The device (1) according to claim 8, wherein an inertial measurement unit for detecting a trajectory is arranged on the measurement frame.

10. 7. The device (1) according to claim 6, wherein the evaluation device (21) is provided with an automatic calibration routine by means of which the distance (a) and / or angle (α) of each of the detection devices (2) detected relative to the inner surface (18) of the correspondingly arranged wheel can be compared with stored values ​​(b).

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