METHOD AND SYSTEM FOR CORRECTING VERTICAL POSITION DEFECTS OF A TRACK

Abstract

The invention relates to a method for correcting vertical position defects of a track after a lifting-tamping process, with a stabilizing process carried out by means of a dynamic track stabilizer in which a stabilizing unit acts on the track at a forward-moving working point in a working direction, with track position data of the untreated track being recorded before the lifting-tamping process, and with track position data of the tamped track being recorded after the lifting-tamping process at a measuring point located in front of the stabilizing unit in the working direction. In this case, additional track position data of the stabilized track are recorded at an post-measuring point located behind the stabilizing unit in the working direction, with the dynamic track stabilizer being actuated during the stabilizing process as a function of track position data of the untreated and the tamped track at the working point and of track position data of the stabilized track at the post-measuring point. The additional post-measurement of the track position after the stabilizing process enables precise control of the dynamic track stabilizer.

Claims

1. A method for correcting vertical position defects of a track after a lifting-tamping process, with a stabilizing process carried out by means of a dynamic track stabilizer in which a stabilizing unit acts on the track at a forward-moving working point in a working direction, with track position data of the untreated track being recorded before the lifting-tamping process, and with track position data of the tamped track being recorded after the lifting-tamping process at a measuring point located in front of the stabilizing unit in the working direction, wherein additional track position data of the stabilized track are recorded at a post-measuring point located behind the stabilizing unit in the working direction, and that the dynamic track stabilizer is actuated during the stabilizing process as a function of track position data of the untreated and the tamped track at the working point and of track position data of the stabilized track at the post-measuring point.

2. A The method according to claim 1, wherein track position data of a target position of the track are predefined, and that the dynamic track stabilizer is additionally actuated during the stabilizing process as a function of correction data which are derived for the working point from the data of the target position and the track position data of the untreated track.

3. The method according to claim 1, wherein a longitudinal gradient or longitudinal level and a crossfall or superelevation of the track are each measured at the respective measuring point to record the track position data.

4. The method according to claim 1, wherein at least one of the following operating parameters of the dynamic track stabilizer is changed during the stabilizing process as a function of the recorded track position data: a vibration frequency, a travelling speed (V.sub.dgs), an imposed load acting on a left rail (al.sub.dgs), an imposed load acting on a right rail (ar.sub.dgs), a total imposed load.

5. The method according to claim 4, wherein the stabilizing process is started with an output value of the respective operating parameter, and that an adjusted value is continuously calculated for the respective operating parameter during the stabilizing process by means of an algorithm set up in a computing unit.

6. The method according to claim 5, wherein weighting factors are stored in the algorithm for the respective operating parameter, and that the weighting factors are continuously adjusted by means of a control.

7. The method according to claim 1, wherein a track position measuring system comprising a plurality of measuring devices is carried along with the dynamic track stabilizer, and that the corresponding track position with respect to a common reference system is recorded at the respective measuring point by means of the assigned measuring devices.

8. The method according to claim 7, wherein the reference system is formed by means of a camera attached to one of the measuring devices and a reference mark attached to another measuring device and positioned in a recording area of the camera, and that measuring marks attached to the remaining measuring devices are recorded by means of the camera in order to record the track position data.

9. A system for carrying out a method according to claim 1, having a track position measuring system and having a dynamic track stabilizer for correcting vertical position defects at a forward-moving working point of a track, wherein the track position measuring system is set up to record the track position at a measuring point arranged in front of the dynamic track stabilizer in the working direction and at a post-measuring point arranged after the dynamic track stabilizer in the working direction, that the dynamic track stabilizer comprises a control device to which track position data recorded by means of the track position measuring system are fed, and that the control device is set up to actuate the dynamic track stabilizer as a function of track position data assigned to the working point and the post-measuring point.

10. The system according to claim 10, wherein a distance between the working point and the post-measuring point lies in a range between 3 m and 10 m, particularly between 5 m and 8 m.

11. The system according to claim 10, wherein the control device comprises a computing unit in which an algorithm is implemented for recalculating at least one operating parameter of the dynamic track stabilizer on the basis of continuously updated track position data.

12. The system according to claim 9, wherein a stabilizing unit comprises a vibration generator and roller clamps that can be clamped onto rails of the track and is supported against a machine frame with imposed load drives that can be actuated separately.

13. The system according to claim 9, wherein a tamping machine is arranged immediately in front of the track stabilizer in the working direction, and that the track position measuring system comprises at least one measuring device which is assigned to the tamping machine.

14. The system according to claim 9, wherein a camera is attached to a first measuring device, that a reference mark is attached to a second measuring device, and that at least one further measuring device with a measuring mark is attached between the first and second measuring device.

15. The system according to claim 14, wherein the track position measuring system comprises a flash lamp that can be actuated together with the camera.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In the following, the invention is explained by way of example with reference to the accompanying figures. The following figures show in schematic illustrations:

[0025] FIG. 1 Dynamic track stabilizer behind a tamping machine

[0026] FIG. 2 Track position measuring system with five measuring devices in a top view

[0027] FIG. 3 Stabilizing unit with machine frame and track in a sectional view

[0028] FIG. 4 Optical measuring arrangement with passive markers

[0029] FIG. 5 Optical measuring arrangement with active markers

[0030] FIG. 6 Optical measuring arrangement with redundant markers

DESCRIPTION OF THE EMBODIMENTS

[0031] A dynamic track stabilizer (DGS) 1 shown in FIG. 1 is an independent track construction machine with a machine frame 2 supported on rail running gears 3 that is moveable on a track 4. In the example described, this dynamic track stabilizer 1 is operated together with a tamping machine 5. However, the invention also relates to a method in which the dynamic track stabilizer 1 is used independently of a tamping machine 5 in terms of time.

[0032] In a variant not shown, the tamping machine 5 and the dynamic track stabilizer 1 form a combined track construction machine. The cyclic forward movement of a tamping unit 6 is adjusted to the continuous forward movement of the dynamic track stabilizer 1, for example, via a longitudinally shiftable auxiliary frame (satellite).

[0033] The cyclically working tamping machine 5 shown in FIG. 1 is arranged before the dynamic track stabilizer 1 with respect to a working direction 7. An overdrawn course of a track position changing in the working process serves for better illustration. A front rail running gear 3 of the tamping machine 1 travels on the untreated track 4. A measuring device 8 is guided in front of it to record an actual position of this untreated track section. This measuring device 8 is an element of a track position measuring system 9 for recording track position data at different measuring points 10. In addition or in an alternative embodiment of the method, track position data of the untreated track 4 are recorded by means of a separate track inspection vehicle.

[0034] In the example according to FIG. 1, a measuring system 9 with measuring chords is assigned to the tamping machine 1 as a reference system. The dynamic track stabilizer 1 comprises a further measuring system 9 with its own measuring chords. In the case of machines 1, 5 operated in a formation, these two measuring systems 9 are combined into a common track position measuring system 9. Advantageously, all recorded track position data are processed by means of a common evaluation device 11. If necessary, a data transmission takes place between the tamping machine 5 and the dynamic track stabilizer 1 via an air interface.

[0035] Subsequently, the track position data are fed to a control device 12 for adaptive actuation of the dynamic track stabilizer 1. If necessary, track position data of the untreated or already tamped track 4 recorded by a separate track inspection vehicle are transferred to the control device 12 in advance or transmitted via a radio connection.

[0036] During a lifting-tamping process, a track panel formed by sleepers 13 and rails 14 attached thereon is lifted out of a ballast bed 15. For this purpose, the tamping machine 5 comprises a lifting unit 16, which is arranged in front of the tamping unit 6. In between there is another measuring device 8 for recording a performed lifting 17. In the raised track position, tamping tines of the tamping unit 6 penetrate the ballast bed 15. Under the application of vibration, a squeezing movement takes place in which the ballast is pushed under the raised sleepers 13 and compacted. In this way, the track 4 is temporarily fixed in an overlifted track position.

[0037] In the variant shown, each measuring device 8 is designed as a rail-guided device. The respective device 8 comprises wheel-flange rollers which are pressed against the inner sides of the rails 14 by means of a spreading axle. A non-contact variant of the respective measuring device 8 comprises a carrier on which measuring sensors (e.g. laser scanners) directed towards the rails 14 are arranged. By means of these sensors, the position of the measuring device 8 in relation to the rails 14 is recorded.

[0038] At the last measuring point 10 of the track position measuring system 9 of the tamping machine 1, in the working direction 7, there is, for example, a measuring device 8 with an inertial measurement unit (IMU) 18. This is arranged on a measuring frame 19, which is guided on the rails 14 by four wheel-flange rollers. With this measuring device 8, track position data of the tamped track 4 are recorded in a known manner. At the same time, the measuring device 8 serves as the rear reference unit of a chord measuring system set up on the tamping machine 5.

[0039] The overlifted track position is lowered to a final target track position 20 in a subsequent stabilizing process. The dynamic track stabilizer 1 is used here. The dynamic track stabilizer 1 is actuated as a function of measuring data recorded at a plurality of measuring points 10, including a post-measuring point 21. Specifically, a controlled lowering of the track 4 takes place by means of the dynamic track stabilizer 1 at a forward-moving working point 22 with the machine 1 in the working direction 7.

[0040] At this working point 22, a stabilizing unit 23 with roller clamps 24 is clamped onto the rails 14 (FIG. 3). A vibration generator 25 arranged on the stabilizing unit 23 causes the track panel in the area of the working point 22 to vibrate horizontally at a predefined frequency. A support of the stabilizing unit 23 against the machine frame 2 is provided by imposed load drives 26, each of which is assigned to the rail 14 located below it. These imposed load drives 26 are designed, for example, as hydraulic cylinders that can be actuated separately. The static imposed load, which acts on the assigned rail 14 via wheel-flange rollers 27 of the stabilizing unit 23, can be changed by changing the pressure applied. A measuring device 8 is arranged immediately behind the working point 22 in order to record the track lowering currently being carried out.

[0041] In a track position measuring system 9 designed as a chord measuring system, this measuring device 8 serves on the one hand to control the lowering of the track 4 and on the other hand for post-measurement of the undisturbed actual track position 28 after stabilization. In the example shown, a total of four measuring devices 8 are arranged on the dynamic track stabilizer 1. Seen from the front, the first measuring device 8 is guided on a track section with an overlifted track position. The second measuring device 8 is located directly behind the stabilizing unit 23. Behind this, the third and fourth measuring device 8 are also arranged at defined distances from each other.

[0042] The four measuring devices 8 form two three-point measuring systems with corresponding measuring chords. To control the lowering, a chord is tensioned over each rail 14 between the first and the third measuring device 8. The reference system for post-measurement of the undisturbed track 4 is formed by measuring chords tensioned between the second and the fourth measuring device 8. On the respective measuring device 8 positioned in between, the distance (versine) to the assigned measuring chord is measured and the track position is derived therefrom according to the known moving-chord measuring principle. The position of the third measuring device 8 defines the post-measuring point 21. In order to precisely record the position of the unaffected track 4, a distance a between the post-measuring point 21 and the working point 22 is, for example, 6 m. Alternatively, the third measuring device 8 is designed as a measuring trolley with an inertial measurement unit 18 arranged on a measuring frame 19. In this case, the post-measurement is only carried out by means of this adapted measuring device 8.

[0043] The stabilizing unit 23 is designed either as a single unit or as a double unit. A double unit comprises two sets of units of approximately the same design, guided one behind the other on the track 4. In FIG. 1, such a second set of units is drawn with dotted lines. With a double unit, vibrations with different directions can be introduced into the track 4 at the same time, resulting in more variable operating parameters compared to a single unit.

[0044] According to the invention, at least one operating parameter of the dynamic track stabilizer 1 is changed as a function of recorded track position data during a stabilizing process. Essential here is the recording of track position data at a plurality of measuring points 10, 21, namely at measuring points 10 upstream of the stabilizing unit 23 and at a post-measuring point 21 behind the stabilizing unit 23. In the example according to FIG. 1, the corresponding measurements are carried out by means of the described three-point measuring systems and the inertial measurement unit 18.

[0045] In an improved variant, the measurement of the track position changing in the working process is carried out by means of an optical measuring system 9, as shown in FIG. 2. The advantage of this variant is a common reference system for all measurements carried out. With respect to the working direction 7, a rear measuring device 8 comprises a camera 29 directed towards all measuring devices 8 located in front thereof. A measuring mark 30 is arranged on each of these measuring devices 8 located in front thereof, with one being defined as a reference mark 30. A virtual optical chord 31, which serves as a reference base for the position of the other measuring marks 30, is tensioned between the reference mark 30 and the camera 29. All marks 30 of the measuring system 9 lie in a recording area 32 of the camera 29. The respective measuring or reference mark 30 comprises, for example, a crosshair on a reflective surface.

[0046] In the evaluation device 11 of the track position measuring system 9, the recordings of the camera 29 are continuously evalua ted. The distances of the measuring devices 8 to each other and an imaging scale of the camera 29 are known. With these known size ratios, the evaluation device 11 calculates an actual change in position of the measuring mark 30 with respect to the optical chord 31 from a shifting of a measuring mark 30 imaged on an image sensor. In a predefined coordinate system x,y,z, the corresponding shifting values ?x, ?y result (FIG. 4). These calculated shifting values ?x, ?y correspond to versine values recorded with a conventional chord measuring system.

[0047] Advantageously, the camera 29 is set up to record monochrome images in order to optimize the evaluation. The resolution of the image sensor, for example, is 5 megapixels. This allows shiftings of the measuring marks 30 to be recognized in millimetres. A recording frequency of approx. 200 Hz ensures that changes in position are detected immediately. Thus, approx. 200 measurements are taken per second.

[0048] In an advantageous further development, the camera 29 is coupled with a flash lamp 33. For example, a plurality of high-power LEDs are arranged around a lens of the camera 29 to flash in the direction of the measuring marks 30 synchronously with the triggering of the camera 29. In this embodiment, the measuring marks 30 are designed as passive elements of the track position measuring system 9 (FIG. 4). For example, the respective measuring mark 30 is affixed as a retro-reflective foil to a suitable surface of the assigned measuring device 8.

[0049] FIG. 5 shows active measuring marks 30. These are actuated together with the camera 29 and light up in the direction of the camera 29. Preferably, high-power LEDs which flash synchronously with the triggering of the camera 29 are also used here. The respective measuring mark 30 comprises a transparent foil which is backlit by an LED flash lamp 33 with diffused light. Compared to a passive measuring mark, a higher light intensity is achievable, giving better results particularly in dusty environments and in bad weather.

[0050] A further improvement of the track position measuring system 9 used in the present invention is shown in FIG. 6. It is taken into account that in exceptional cases obstacles 34 may lie between the camera 29 and the measuring marks 30. For example, in the case of strong deflections in track curves, individual unit parts can temporarily cover the respective visual axis. A plurality of redundant measuring marks 30 are assigned to a measuring device 8 so that the position of the measuring device 8 can still be reliably recorded even if one of the measuring marks 30 does not appear in the image of the camera 29.

[0051] Based on the recorded track position data, the following operating parameters of the dynamic track stabilizer 1 are continuously adjusted, for example: [0052] f.sub.ags . . . vibration frequency of the vibration generator 24 [0053] al.sub.dgs . . . imposed load of the stabilizing unit 23 on the left rail 14 [0054] ar.sub.dgs . . . imposed load of the stabilizing unit 23 on the right rail 14 [0055] ag.sub.dgs . . . total imposed load [0056] V.sub.dgs . . . pass speed (forward speed) of the stabilizing unit 23

[0057] The track position data recorded in the working direction 7 in front of stabilizing unit 23 are assigned to the current working point 22. This means that all track position data with a local assignment to the track 4 are recorded before the stabilizing process. For example, the track position data are supplemented with position data from a navigation satellite system (GNSS data). With known distances between the measuring points 10 and the working point 22, a simple reference can be established via a recorded distance.

[0058] Specifically, the following measuring data are recorded in advance and then used to adjust the operating parameters when the respective measuring point 10 corresponds to the current working point 22: [0059] h.sub.ivs . . . actual longitudinal level of the untreated track 4 [0060] q.sub.ivs . . . actual crossfall (actual superelevation) of the untreated track 4 [0061] h.sub.ins . . . actual longitudinal level of the tamped track 4 [0062] q.sub.ins . . . actual crossfall (actual superelevation) of the tamped track 4

[0063] In addition, predefined values for a final target track position are used to adjust the operating parameters: [0064] h.sub.s . . . target longitudinal level of the finished track 4 [0065] q.sub.s . . . target crossfall (target superelevation) of the finished track 4

[0066] Exemplary formulae for the continuous adjustment of the operating parameters use the following weighting factors: [0067] g.sub.f1 . . . 1.sup.st weighting factor for vibration frequency [0068] g.sub.f2 . . . 2.sup.nd weighting factor for vibration frequency [0069] g.sub.a1 . . . 1.sup.st weighting factor for imposed load [0070] g.sub.a2 . . . 2.sup.nd weighting factor for imposed load [0071] g.sub.a3 . . . 3.sup.rd weighting factor for imposed load [0072] g.sub.a4 . . . 4.sup.th weighting factor for imposed load [0073] g.sub.v1 . . . 1.sup.st weighting factor for pass speed [0074] g.sub.v2 . . . 2.sup.st weighting factor for pass speed

[0075] At the beginning of a working operation, the following output values are applied for the operating parameters: [0076] f.sub.0 . . . output value for vibration frequency [0077] a.sub.0 . . . output value for the left and the right imposed load [0078] V.sub.0 . . . output value for the pass speed

[0079] The following formulae are stored in the control device 12 in order to adjust operating parameters of the dynamic track stabilizer 1 during a stabilizing process for the current working position 22:

[00001]$\begin{array}{c}{f}_{\mathrm{dgs}}:=f_0+g_{f1}.Math.\left(h_s-h_{\mathrm{ivs}}\right)+g_{f2}.Math.\left(h_{\mathrm{ins}}-h_s\right)\\ {\mathrm{al}}_{\mathrm{dgs}}:=a_0+g_{a1}.Math.\left(q_s-q_{\mathrm{ivs}}\right)+g_{a2}.Math.\left(q_{\mathrm{ins}}-q_s\right)+g_{a3}.Math.\left(h_s-h_{\mathrm{ivs}}\right)+g_{a4}.Math.\left(h_{\mathrm{ins}}-h_s\right)\\ {\mathrm{ar}}_{\mathrm{dgs}}:=a_0-g_{a1}.Math.\left(q_s-q_{\mathrm{ivs}}\right)-g_{a2}.Math.\left(q_{\mathrm{ins}}-q_s\right)+g_{a3}.Math.\left(h_s-h_{\mathrm{ivs}}\right)+g_{a4}.Math.\left(h_{\mathrm{ins}}-h_s\right)\\ v_{\mathrm{dgs}}:=v_0+g_{v1}.Math.\left(h_s-h_{\mathrm{ivs}}\right)+g_{v2}.Math.\left(h_{\mathrm{ins}}-h_s\right)\\ {\mathrm{ag}}_{\mathrm{dgs}}:={\mathrm{al}}_{\mathrm{dgs}}+a{r}_{\mathrm{dgs}}\end{array}$

[0080] Due to the effect of the dynamic track stabilizer 1, there is a lowering of the track 4 and a change in the longitudinal level and/or the superelevation during the pass. These changes are recorded by the post-measurement of the track position. Accordingly, the following track position data are used to adjust the correction of the track position and the operating parameters: [0081] h.sub.ind . . . actual longitudinal level of the stabilized track 4 [0082] q.sub.ind . . . actual crossfall (actual superelevation) of the stabilized track 4

[0083] For example, an iterative adjustment of the operating parameters was performed by the following formulae stored in the control device 12:

[00002]$\begin{array}{c}?h:=\left(h_s-h_{\mathrm{ind}}\right)\\ ?q:=\left(q_s-q_{\mathrm{ind}}\right)\\ g_{f1}\left(n+1\right):=g_{f1}\left(n\right)+k_{\mathrm{gf}1}.Math.?h\\ g_{f2}\left(n+1\right):=g_{f2}\left(n\right)+k_{\mathrm{gf}2}.Math.?h\\ g_{a1}\left(n+1\right):=g_{a1}\left(n\right)+k_{\mathrm{ga}1}.Math.?q\\ g_{a2}\left(n+1\right):=g_{a1}\left(n\right)+k_{\mathrm{ga}2}.Math.?q\\ g_{a3}\left(n+1\right):=g_{a3}\left(n\right)+k_{\mathrm{ga}3}.Math.?h\\ g_{a4}\left(n+1\right):=g_{a4}\left(n\right)+k_{\mathrm{ga}4}.Math.?h\\ g_{v1}\left(n+1\right):=g_{v1}\left(n\right)+k_{\mathrm{gv}1}.Math.?h\\ g_{v2}\left(n+1\right):=g_{v1}\left(n\right)+k_{\mathrm{gv}2}.Math.?h\end{array}$

[0084] With the iterative adjustment, the original values of the weighting factors are replaced by new values. If both the crossfall and the longitudinal level correspond to the respective target value after the stabilizing process, the dynamic stabilizer 1 is perfectly adjusted and no adaptation of the weighting factors takes place.

[0085] The factors k.sub.gf1, k.sub.gf2, k.sub.ga1, k.sub.ga2, k.sub.ga3, k.sub.ga4, k.sub.gv1, k.sub.gv2 used determine a control gain and are calculated in tests or simulations, for example. The same applies to the output values of the operating parameters f.sub.0, a.sub.0, V.sub.0 and to output values of the weighting factors g.sub.f1(0), g.sub.f2(0), g.sub.a1(0), g.sub.a2(0), g.sub.a3(0), g.sub.a4(0), g.sub.v1(0), g.sub.v2(0). If the method is carried out frequently, experience is gained so that suitable values are available at the beginning of a working operation.

[0086] In the extended method involving the tamping machine 5, the following overlifting values (correction values) are predefined:

[00003]$\begin{array}{c}{h}_{\mathrm{ks}}:=\left(h_s-h_{\mathrm{ivs}}\right).Math.F_h\\ q_{\mathrm{ks}}:=\left(q_s-q_{\mathrm{ivs}}\right).Math.F_q\end{array}$

In a simple embodiment, an invariable factor F.sub.h, F.sub.q is predefined in each case to determine the overlifting values. However, known methods can also be used to continuously adjust the overliftings to changing track conditions.