METHOD AND ARRANGEMENT FOR DETERMINING THE MOTION STATE OF A RAIL VEHICLE WHEEL

Description

[0001] The invention relates to a method for determining the state of motion of a wheel of a rail vehicle in relation to the rail on which the wheel of the rail vehicle travels, as well as a corresponding arrangement.

[0002] In railway engineering, the technical term "skidding" refers to the spinning of a wheel or driven wheel on a rail. During skidding, the peripheral speed of the wheel is thus much greater than the corresponding travel speed of the rail vehicle.

[0003] During spinning, the friction ratio between the driven wheel and the rail is too low, the driven wheel spins virtually "idle", and damage occurs, particularly on the rail, due to increased material removal.

[0004] Rail vehicles are equipped with so-called anti-skid devices which are intended to prevent skidding by briefly reducing the tractive force when the rail vehicle starts moving in order to ensure an optimised transfer of tractive force from the drive of the rail vehicle to the rail.

[0005] The term "gliding" refers to the rotation-free sliding of the wheel or braked wheel on the rail. During sliding, the circumferential speed of the wheel is therefore much lower than the associated speed of the rail vehicle.

[0006] When sliding, the friction ratio between a brake acting on the wheel is too high, the braked wheel locks, and damage occurs, particularly on the wheel, due to increased material removal.

[0007] Rail vehicles are equipped with so-called anti-skid devices which are intended to prevent sliding when the rail vehicle is braked by briefly reducing the braking force in order to ensure an optimised transmission of braking force from the braking system of the rail vehicle to the rail.

[0008] The term "rolling" refers to a "normal" rotational movement of the wheel, in which the circumferential speed of the wheel during operation, when starting and also when braking, corresponds at least approximately to the assigned, respective driving speed of the rail vehicle.

[0009] In summary, skidding, sliding and rolling form three states of motion of the wheel of the rail vehicle.

[0010] Various systems for anti-skid and anti-skid protection are known, based on measurements of different physical quantities and using sensors. For example, the angular velocity of the wheel is determined via a tachogenerator, or the torque of a drive is determined via measured values ​​from the associated current / voltage converter.

[0011] Due to the measurement method described, these systems are often too slow and therefore react too late to problems that occur during propulsion or braking.

[0012] JP S 59175302 A discloses an optical detection of the slipping and sliding conditions of a train.

[0013] It is therefore the object of the present invention to provide an improved method and a corresponding arrangement for determining the state of movement of a rail vehicle wheel, which enables a rapid and reliable determination of the operating state with little additional effort.

[0014] This problem is solved by the features of the independent patent claims. Advantageous further developments are specified in the subclaims.

[0015] The method according to the invention is camera-based and uses known image processing methods or image processing algorithms.

[0016] In the method according to the invention for determining the state of motion of a wheel of a rail vehicle relative to the rail on which the wheel of the rail vehicle travels, a camera focused on a wheel-rail area on the rail vehicle captures consecutive images of the wheel-rail area as an image sequence. The wheel-rail area includes at least a partial area of ​​a wheel of the rail vehicle and at least a partial area of ​​a rail on which the wheel is to travel.

[0017] In the images, an area is determined along which the parts of the wheel and the rail touch.

[0018] In a first image of the image sequence, at least one characteristic point is determined for the rail section, which is clearly visually recognizable in the first image and in images following the first image. This point can be assigned as a component to the rail section. Similarly, in the first image, at least one characteristic point is determined for the wheel section, which is clearly visually recognizable in the first image and in the images following the first image. This point can be assigned as a component to the wheel section.

[0019] For consecutive images, the respective distances of the characteristic points to the contact area are determined. The wheel's motion state is determined from the change in the distance of the characteristic points to the contact area that results over the consecutive images.

[0020] In an advantageous further development, a straight line is determined as the area along which the parts of the wheel and the rail touch.

[0021] In an advantageous further development, the rail head is filmed by the camera as a part of the rail and / or the wheel running surface is filmed by the camera as a part of the wheel.

[0022] In an advantageous further development, a high-resolution camera system is used as the camera and / or a system that operates in the infrared light range or in the ultraviolet light range is used as the camera.

[0023] In an advantageous further development, the motion states of the wheel are determined as either rolling, sliding or skidding.

[0024] In the event that both the distance between the contact area and the characteristic point of the rail section and the distance between the contact area and the characteristic point of the wheel section change uniformly and in the same direction, the wheel's state of motion is determined to be "rolling".

[0025] In the event that the distance between the contact area and the characteristic point of the wheel sub-area changes, while the distance between the contact area and the characteristic point of the rail sub-area remains essentially unchanged, the wheel's motion state is determined to be "skidding".

[0026] In the event that the distance between the contact area and the characteristic point of the rail section changes, while the distance between the contact area and the characteristic point of the rail section remains essentially unchanged, the motion state of the wheel is determined to be "sliding".

[0027] In an advantageous further development, a large number of characteristic points are used both on the part of the rail and on the part of the wheel in order to refine the analysis of the state of motion via respective changes in distance to the contact area and to initiate correspondingly finely tuned counter-regulations for skidding or sliding in the rail vehicle.

[0028] In an advantageous further development, information regarding the determined operating mode is transmitted to a drive control of the rail vehicle and / or to a brake control of the rail vehicle in order to initiate a respective counter-regulation in the rail vehicle.

[0029] In an advantageous further development, the rail vehicle's drive control system reduces the traction force when skidding is detected in order to at least counteract the skidding. Similarly, the rail vehicle's brake control system reduces the traction force when skidding is detected in order to at least counteract the skidding.

[0030] In an advantageous further development, the camera images are used to monitor and / or evaluate the rail condition of a rail line.

[0031] In an advantageous further development, damage, surface changes, surface discolorations and / or structures on the partial area of ​​the rail or wheel are used as characteristic points.

[0032] In an advantageous further development, markings are used as characteristic points, which are attached to the part of the rail or the part of the wheel.

[0033] The method according to the invention makes it possible to detect both skidding and sliding of a driven or braked wheel very quickly, reliably and precisely.

[0034] The method according to the invention makes it possible to reduce or completely prevent wear on both the wheel, more precisely on the wheel tread, and on the rail, more precisely on the rail head.

[0035] The method according to the invention enables an improvement or optimization of a drive control or a brake control with which the rail vehicle is subjected during operation.

[0036] The method according to the invention enables a current or subsequent visualization and evaluation of wheel movement states along a rail or railway line as well as an evaluation of the line condition.

[0037] The method according to the invention eliminates the need for previously required operating resources, such as sand or compressed air for a rail vehicle's starting aid. This also supports and enables environmentally friendly operation of the rail vehicle.

[0038] The method according to the invention can be used reliably regardless of the time of day and even in bad weather conditions.

[0039] This is achieved, for example, by a suitable choice of the camera system used (e.g. its resolution) and the wavelength range used for observation (infrared light, ultraviolet light) in which the camera system operates.

[0040] The method according to the invention extends maintenance intervals for reprofiling wheel discs. At the same time, wear and tear on the infrastructure is reduced, particularly in stations and on track gradients.

[0041] The invention is explained in more detail below with reference to a drawing. It shows: FIG 1 shows the working principle of the invention in an overview, FIG 2 shows with reference to FIG 1 a contour extraction to determine a straight line, FIG 3 shows with reference to FIG 1 and FIG 2 a determination of characteristic points, FIG 4with reference to FIG 3 a determination of distances of the characteristic points to the straight line, FIG 5 with reference to the preceding figures the method according to the invention in a flow chart, FIG 6 in a schematic representation the use of the camera images which are taken within the scope of the invention, FIG 7 a rail vehicle with an arrangement of the cameras for the method according to the invention.

[0042] FIG 1 shows the working principle of the invention in an overview.

[0043] A rail vehicle is equipped with a camera, preferably a high-resolution camera, which is directed or focused on a wheel-rail area.

[0044] In this area, at least a partial area of ​​a wheel RD of the rail vehicle and at least a partial area of ​​a rail SCH on which the wheel is to travel can be seen.

[0045] Preferably, the camera captures a wheel tread RDLF as a partial area of ​​the wheel RD in successive images, while a rail head SCHK is captured as a partial area of ​​the rail SCH.

[0046] In successive images from the camera, a straight line GER is determined between the rail head SCHK and the wheel tread RDLF with the aid of camera or evaluation electronics, along which the two touch each other.

[0047] In successive camera images, the evaluation electronics determine a characteristic point P1SK on the rail head SCHK. Similarly, a characteristic point P1RDLF is determined on the wheel tread RDLF.

[0048] Visually recognizable and clearly identifiable points are used as characteristic points P1SK and P1RDLF. These include, for example, noticeable damage, surface changes, surface discoloration, etc., on the rail head SCHK or the wheel tread RDLF.

[0049] Alternatively or in addition, specially designed markings are used as characteristic points, which are attached to the rail head SCHK or to the wheel tread RDLF.

[0050] In successive camera images, the evaluation electronics determine a distance D1SK between the characteristic point P1SK and the straight line GER. Similarly, a distance D1RDLF is determined between the characteristic point P1RDLF and the straight line GER.

[0051] These distances D1SK, D1RDLF change depending on the state of motion of the wheel RD of the rail vehicle.

[0052] When the wheel moves in the direction of travel FRTR When rolling, the two distances D1SK, D1RDLF will decrease evenly, when skidding (i.e. when the wheel RD is spinning) the distance D1RDLF will decrease while the distance D1SK will remain essentially the same, and when sliding (i.e. when the wheel RD is locked) the distance D1RDLF will remain essentially the same while the distance D1SK will decrease.

[0053] By analyzing the successive images, the movement state of the wheel RD of the rail vehicle is deduced or determined.

[0054] The above-mentioned investigation or evaluation of the distance change is carried out within specified tolerances so that minor deviations in the distance changes that occur during the operational operation of the rail vehicle do not distort the evaluation result.

[0055] FIG 2 shows with reference to FIG 1 a contour extraction, the result of which is the straight line GER between the wheel tread RDLF and the rail head SK.

[0056] FIG 3 shows with reference to the figures FIG 1 , FIG 2 a determination or extraction of characteristic points P1SK, P2SK, P3SK as well as P1RDLF, P2RDLF, P3RDLF.

[0057] FIG 4 shows with reference to FIG 3 the distances D1SK, D2SK, D3SK and D1RDLF, D2RDLF, D3RDLF assigned to the characteristic points P1SK, P2SK, P3SK and P1RDLF, P2RDLF, P3RDLF to the straight line GER.

[0058] Through the FIG 3 and in FIG 4 By using a large number of characteristic points and the associated analysis of the corresponding changes in distance, the analysis of the state of motion is refined and more precise results on the extent of skidding or sliding are determined.

[0059] This allows for finely tuned counter-regulation to reduce or completely prevent skidding or sliding.

[0060] FIG 5 shows, with reference to the preceding figures, the method according to the invention in a flow chart or using an associated software architecture.

[0061] In a first block B1, successive camera images are generated using a high-resolution camera, showing the wheel-rail area.

[0062] In a second block B2, these images are preprocessed and classified in a third block B3, i.e. assigned to a respective monitored wheel of the rail vehicle.

[0063] In a fourth block B4, contour extraction is carried out to determine the straight line along which the wheel (wheel tread) and the rail (rail head) touch.

[0064] In a fifth block B5, one or more characteristic points on the wheel or on the wheel tread are extracted or determined.

[0065] In a sixth block B6, the distance of the characteristic points of the wheel or wheel tread to the straight line is determined.

[0066] In a seventh block B7, one or more characteristic points on the rail or on the rail head are extracted or determined.

[0067] In an eighth block B8, the distance of the characteristic points of the rail or rail head to the straight line is determined.

[0068] In a ninth block B9, the changes in distance of the respective characteristic points to the straight line are determined and an operating mode of the wheel is determined.

[0069] In a tenth block B10, information regarding the determined operating mode is sent to a drive control of the rail vehicle and / or to a brake control of the rail vehicle.

[0070] If wheel skidding is detected, the drive control initiates a temporary reduction in traction force on the rail vehicle in order to reduce or prevent the skidding.

[0071] If wheel slippage is detected, the brake control initiates a temporary reduction in the braking force on the rail vehicle in order to reduce or prevent the slippage.

[0072] FIG 6 shows in a schematic diagram the use of the camera images taken within the scope of the invention.

[0073] The high-resolution images generated by the KAM camera are fed into an image processing program (BVP), where they are analyzed and the operating mode of the wheel is determined.

[0074] In a preferred further development, the image processing program BVP is used to determine or detect the condition of the rails using the images.

[0075] The camera images, the operating mode and / or the rail condition information are preferably sent to a land-based control center LS or a communication platform KOM, for example a RAILIGENT platform, for further processing.

[0076] In a preferred further development, the camera images, the operating mode and / or the rail condition information are fed to a central train control unit ZSG of the rail vehicle.

[0077] In a preferred further development, the central train control unit (ZSG) initiates a radio-controlled transmission for further processing via a remote data transmission (DFÜ) of the rail vehicle.

[0078] In a preferred further development, the central train control unit ZSG initiates the documentation via a memory SP of the rail vehicle.

[0079] In a preferred further development, the central train control unit ZSG initiates the above-mentioned countermeasures via a drive control unit ASG or a brake control unit BSG in order to counteract skidding or sliding.

[0080] In a preferred further development, the central train control unit ZSG provides information to the driver of the rail vehicle via an HMI display unit.

[0081] This information preferably concerns the determined operating mode of the wheel and / or suitable countermeasures that the driver should initiate.

[0082] In a preferred further development, this information contains a message about countermeasures that have been automatically taken and already implemented in order to inform the train driver about the drive or braking situation.

[0083] FIG 7 shows a rail vehicle SFZ for the method according to the invention as well as an advantageous arrangement of the cameras KAM used in the method according to the invention, which, as shown here, are arranged individually for each individual wheel RD.

Claims

1. Method for determining the movement state of a wheel (RD) of a rail vehicle (SFZ) with respect to the rail (SCH) traversed by the wheel (RD) of the rail vehicle (SFZ), - wherein a camera (KAM) focused on a wheel-rail region on the rail vehicle (SFZ) is used to capture, as an image sequence, successive images of the wheel-rail region, wherein the wheel-rail region contains at least a sub-region (RDLF) of a wheel (RD) of the rail vehicle (SFZ) as well as at least a sub-region (SK) of a rail (SCH) to be traversed by the wheel (RD), - wherein a region (GER), as a contact region (GER), is ascertained in the images, along which the sub-region (RDLF) of the wheel (RD) and the sub-region (SK) of the rail (SCH) are in contact, - wherein in a first image of the image sequence of the sub-region (SK) of the rail (SCH) at least a characteristic point (PlSK) is ascertained which is clearly optically recognizable in the first image and in images which follow the first image, - wherein in the first image of the sub-region (RDLF) of the wheel (RD) at least one characteristic point (PlRDLF) is ascertained which is clearly optically recognizable in the first image and in the images which follow the first image, - wherein for the successive images of the sub-region (SK) of the rail (SCH), respective distances (DlSK) of the characteristic points (PlSK) from the contact region (GER) are determined, - wherein for the successive images of the sub-region (RDLF) of the wheel (RD), respective distances (DlRDLF) of the characteristic points (PlRDLF) from the contact region (GER) are determined, - wherein the movement state of the wheel (RD) is determined from a change in the distance (DlSK, DlRDLF) of the characteristic points (PlSK, PlRDLF) from the contact region (GER), which results from the successive images.

2. Method according to Claim 1 wherein a straight line (GER) is ascertained as the region (GER) along which the sub-regions (RDLF, SK) of the wheel (RD) and the rail (SCH) are in contact.

3. Method according to Claim 1 or 2, - wherein the rail head (SK) of the rail (SCH) is filmed by the camera (KAM) as the sub-region of the rail (SCH), and / or - wherein the wheel running surface (RDLF) of the wheel (RD) is filmed by the camera (KAM) as the sub-region of the wheel (RD) .

4. Method according to Claim 1, - wherein a high-resolution camera system is used as the camera (KAM), and / or - wherein a system that operates in the infrared light range or in the ultraviolet light range is used as the camera (KAM).

5. Method according to Claim 1 wherein either rolling or sliding or skidding is determined as the movement state of the wheel.

6. Method according to Claim 5, wherein for the case in which both the distance (DlSK) between the contact region (GER) and the characteristic point (PlSK) of the sub-region (SK) of the rail (SCH) and the distance (DlRDLF) between the contact region (GER) and the characteristic point (PlRDLF) of the sub-region (RDLF) of the wheel (RD) change equally and in the same direction, rolling is determined as the movement state of the wheel (RD).

7. Method according to Claim 5, wherein for the case in which the distance (DlRDLF) between the contact region (GER) and the characteristic point (PlRDLF) of the sub-region (RDLF) of the wheel changes, whereas the distance (DlSK) between the contact region (GER) and the characteristic point (PlSK) of the sub-region (SK) of the rail (SCH) remains essentially unchanged, skidding is determined as the movement state of the wheel (RD).

8. Method according to Claim 5, wherein for the case in which the distance (DlSK) between the contact region (GER) and the characteristic point (PlSK) of the sub-region (SK) of the rail (SCH) changes, whereas the distance (DlRDLF) between the contact region (GER) and the characteristic point (PlRDLF) of the sub-region (RDLF) of the rail (SCH) remains essentially unchanged, sliding is ascertained as the movement state of the wheel (RD).

9. Method according to any one of the preceding claims, wherein a plurality of characteristic points (PlSK, P2SK, P3SK, PlRDLF, P2RDLF, P3RDLF) are used both for the sub-region (SK) of the rail (SCH) and for the sub-region (RDLF) of the wheel (RD) in order to refine the analysis of the movement state over respective changes in distance (DlSK, D2SK, D3SK, DlRDLF, D2RDLF, D3RDLF) from the contact region (GER) and in order to initiate correspondingly finely tuned counter-adjustments for skidding or sliding of the rail vehicle.

10. Method according to any one of the preceding claims, wherein information about the ascertained operating mode is transmitted to a drive control system of the rail vehicle and / or to a brake control system of the rail vehicle in order to initiate a corresponding counter-adjustment of the rail vehicle.

11. Method according to Claim 10, - wherein a traction force reduction is carried out by the drive control system of the rail vehicle when skidding is detected on the rail vehicle in order to at least counteract the skidding, or - wherein a traction force reduction is carried out by the brake control system of the rail vehicle when sliding is detected on the rail vehicle in order to at least counteract the sliding.

12. Method according to Claim 1, wherein the camera images are used for monitoring and / or for assessing a rail condition of a railway line.

13. Method according to any one of the preceding claims, wherein - damage, surface changes, surface discoloration and / or structures on the sub-region (RDLF) of the rail (SCH) or of the wheel (RD), or - markings that are attached to the sub-region (SK) of the rail (SCH) or to the sub-region (RDLF) of the wheel (RD) are used as the characteristic points (PlSK, PlRDLF).

14. Arrangement for determining the movement state of a wheel (RD) of a rail vehicle (SFZ), - with a wheel (RD) of a rail vehicle (SFZ) and with a rail (SCH) that is traversed by the wheel (RD) of the rail vehicle (SFZ), - with a camera (KAM) arranged on the rail vehicle (SFZ) and focused on a wheel-rail region, - wherein the camera is designed in such a way that, as an image sequence, successive images of the wheel-rail region are recorded, wherein the wheel-rail region contains at least one sub-region (RDLF) of a wheel (RD) of the rail vehicle (SFZ) and at least one sub-region (SK) of a rail (SCH) to be traversed by the wheel (RD), - and with means for image analysis designed to carry out the method according to any one of Claims 1 to 13.