Method for reducing a longitudinal vibration

Abstract

The invention relates to a method for reducing a longitudinal vibration (LS) in a train (ZG), wherein the train has at least one driven unit (AE) and at least one rail vehicle (WA) connected thereto. A movement force (AK-AE) is applied to the train (ZG) in order to drive the train (ZG) in a targeted manner or to brake the train (ZG) in a targeted manner. A longitudinal vibration (LS) occurring in the train is detected. A temporal progression (t(LS)) of the longitudinal vibration (LS) is determined and fed into an algorithm (ALG). A counterforce (DAK-AE) is determined by the algorithm (ALG) in such a way that the counterforce (DAK-AE), by being combined with the movement force (AK-AE), dampens the longitudinal vibration (LS). The counterforce (DAK-AE) is applied in the train in order to reduce the longitudinal vibration in the train.

Description

Method for reducing a longitudinal vibration The invention relates to a method for reducing a longitudinal vibration for a train comprising at least one driven unit. Introduction It is known that a train that comprises, for example, a driven unit and at least one car coupled thereto as elements can experience a longitudinal vibration. The longitudinal vibration is produced as a result of the coupled elements of the train interacting via coupling elements that are used and is also dependent, inter alia, on a speed of travel of the train. The longitudinal vibration generates forces that additionally act on the coupling elements used and may place them under stress. If a coupling element has its stress limit exceeded, breakage of the coupling element may cause train separation. In particular trains consisting of tank cars are susceptible to such a longitudinal vibration, which preferably arises when the train is accelerated or braked. This problem is currently solved by virtue of an engineer of the train identifying an occurring longitudinal vibration and accordingly taking targeted countermeasures: in order to reduce the longitudinal vibration, he / she slows the train based on their experience in train operation or accelerates the train as appropriate. In summary, when a longitudinal vibration occurs, he / she opposes a motive force of the train that drives or slows the train with a counterforce that, in conjunction with the motive force, causes the longitudinal vibration to be reduced. This approach is thus based on early identification of the longitudinal vibration by the engineer of the train and on their experience, in order firstly to sufficiently reduce the longitudinal vibration and secondly to maintain safe operation of the train. This intervention by the engineer disadvantageously causes a perceptible change in train dynamics and an increased energy consumption. Owing to the "human factor" and owing to the possibilities that there are for the longitudinal vibration to form and be reduced, this approach is not very well developed and not very satisfactory. Objective It is therefore the object of the present invention to specify an improved method for reducing an occurring longitudinal vibration for a train. This object is achieved by the features of claim 1. Advantageous developments are specified in the dependent claims. Invention The inventive method for reducing a longitudinal vibration relates to a train that comprises at least one driven unit and at least one rail vehicle connected thereto. The train has a motive force applied to it in order to drive the train in a deliberate manner or in order to slow the train in a deliberate manner. The motive force allows normal or trouble-free train operation. A longitudinal vibration arising for the train is detected as a disruption to train operation. A time characteristic of the longitudinal vibration is determined and fed to an algorithm. The algorithm determines a counterforce such that the counterforce, when superimposed on the motive force, causes the disruptive longitudinal vibration to be absorbed. The counterforce thus determined is implemented in the train in order to reduce the disruptive longitudinal vibration in the train. In a preferred development, the time characteristic of the longitudinal vibration is determined in amplitude and frequency. In a preferred development, a sensor is used to detect the longitudinal vibration and / or to determine the time characteristic of the longitudinal vibration. In a preferred development, the counterforce is introduced into the train, and implemented, by the driven unit and / or by the at least one rail vehicle. The counterforce acts, for example, as an (additional) driving force or as an (additional) braking force that is introduced into the train as appropriate in order to use the superimposition on the motive force to reduce the longitudinal vibration in the train. In a preferred development, the counterforce is superimposed on the motive force as a time characteristic. In a preferred development, the counterforce is determined and / or superimposed and / or implemented in the train in an automated manner. This is done in particular without the involvement of an engineer of the train. In a preferred development, the algorithm is tailored to an operating behavior of the driven unit in order to take into account previously known time delays in the counterforce implementation in the train. In a preferred development, the sensor used is an acceleration sensor. In a preferred development, the sensor used is a sensor - that is arranged close to or on the driven unit, or - that is arranged close to or on a coupling that connects the driven unit to the rail vehicle, or - that is arranged close to or on a coupling that connects two adjacent rail vehicles of the train to one another. In a preferred development, the driven unit used is a locomotive or a railcar or a driven wheelset or a driven bogie. Advantages of the invention: The present invention provides a dependable and automated solution for reducing a longitudinal vibration in the train. The present invention delivers a reliable method for reducing the longitudinal vibration, which is carried out in an automated manner independently of the engineer. Manual intervention by the engineer according to the known prior art disadvantageously results in perceptible changes in train dynamics being caused. These disadvantageous changes are avoided by the present invention. The present invention  allows gentle and yet effective implementation of the counterforce in an automated manner. The   present   invention   influences train   dynamics only insignificantly and achieves energy savings. The present invention prevents hitherto critical longitudinal vibrations that occur in particular in the case of very long trains transporting goods and can lead to breakage of coupling elements, and thus prevents train separation. Description of the figures The invention is explained in more detail below with the aid of a drawing, in which: FIG. 1 shows details pertaining to the present invention, and FIG. 2 shows a flowchart for the present invention with reference to FIG. 1, and FIG. 3 to FIG. 6 show a longitudinal vibration arising and being reduced for the train. FIG. 1 shows details pertaining to the present invention. The method for reducing a longitudinal vibration LS is used for a train ZG that comprises at least one driven unit AE, in this case a locomotive, and rail vehicles WA connected thereto, in this case tank cars. The driven unit AE has a motive force or a driving force AK-AE applied to it in order to influence the movement of the train ZG in a defined or deliberate manner in line with driving or braking. The driving force AK-AE may be the joint cause of an arising longitudinal vibration LS for the train ZG. The driving force AK-AE may be a force for accelerating or driving the train or a force for braking the train. The train ZG uses sensors SEN to detect the longitudinal vibration LS occurring in the train ZG. The sensors SEN used in this case are acceleration sensors. In this case, a sensor SEN is arranged on the driven unit AE, for example on a car body of the driven unit AE. Additionally, further sensors SEN are arranged on couplings KUP in order to detect the longitudinal vibration LS. The coupling KUP connects the driven unit AE to a rail vehicle WA or connects two adjacent rail vehicles WA of the train ZG. The train ZG determines a time characteristic t(LS) of the longitudinal vibration LS (preferably in frequency f(LS) and amplitude A(LS)) and feeds it to an algorithm ALG, which in this case is part of a control system of the driven unit AE. The algorithm ALG takes the time characteristic of the longitudinal vibration LS as a basis for determining a difference driving force DAK-AE as a counterforce for the driven unit EA of the train ZG in such a way that superimposition of the driving force AK-AE on the difference driving force DAK-AE reduces the longitudinal vibration LS. The algorithm ALG preferably begins by determining the counterforce when a predetermined amplitude value for the longitudinal vibration LS is exceeded as a limit value. The difference driving force DAK-AE may be a force for braking the train or a force for accelerating the train. The difference driving force DAK-AE is implemented as a counterforce by the driven unit EA in such a way that the detected longitudinal vibration LS is reduced. FIG. 2 shows a flowchart for the present invention with reference to FIG. 1. In a first step S1, the train ZG uses the sensor SEN to detect the longitudinal vibration LS occurring in the train ZG. In a second step S2, the train ZG determines the time characteristic t(LS) of the longitudinal vibration LS in frequency f(LS) and amplitude A(LS) and feeds it to the algorithm ALG. In a third step S3, the algorithm ALG takes the time characteristic t(LS) of the longitudinal vibration LS as a basis for determining a difference driving force DAK-AE for the driven unit AE of the train ZG in such a way that superimposition of the driving force AK-AE of the driven unit AE on the difference driving force DAK-AE reduces the longitudinal vibration LS in the train ZG. In a fourth step S4, the difference driving force DAK-AE is implemented by the driven unit AE in such a way that the detected longitudinal vibration LS in the train ZG is reduced. FIG. 3 to FIG. 6 show a longitudinal vibration arising and being reduced for a train that consists of a locomotive and of four attached cars. FIG. 3 shows the train starting up as normal. There is not yet any longitudinal vibration in the train. The locomotive generates a tractive force that is passed on via the interfaces between the locomotive and / or between the cars in the train. The tractive force becomes ever smaller toward the end of the train. FIG. 4 and FIG. 5 show superimposition of forces when the train is starting up. The tractive force exerted by the locomotive during startup is superimposed with a dynamic tractive force and compressive force. As a result, groups of cars move relative to one another and thus produce a wave of relative displacements of the cars that migrates through the train, said displacements forming a longitudinal vibration. FIG. 6 shows the longitudinal vibration being reduced for the train. If the time characteristic (frequency and amplitude) of the longitudinal vibration is known, the locomotive as a driven unit is rendered able to use the principle of an active absorber to reduce the longitudinal vibration or keep it at a very low level.

Claims

1. A method for reducing a longitudinal vibration (LS) for a train (ZG), wherein the train comprises at least one driven unit (AE) and at least one rail vehicle (WA) connected thereto, - in which the train (ZG) has a motive force (AK-AE) applied to it in order to drive the train (ZG) in a deliberate manner or in order to slow the train (ZG) in a deliberate manner,- in which a longitudinal vibration (LS) arising for the train (ZG) is detected,- in which a time characteristic (t(LS)) of the longitudinal vibration (LS) is determined and fed to an algorithm (ALG),- in which the algorithm (ALG) determines a counterforce (DAK-AE) in such a way that the counterforce (DAK-AE), when superimposed on the motive force (AK-AE), causes the longitudinal vibration (LS) to be absorbed, and- in which the counterforce (DAK-AE) is implemented in the train in order to reduce the longitudinal vibration in the train.

2. The method as claimed in claim 1, in which a sensor (SEN) is used to detect the longitudinal vibration (LS) and / or to determine the time characteristic (t(LS)) of the longitudinal vibration (LS).

3. The method as claimed in claim 1, in which the counterforce (DAK-AE) is introduced into the train (ZG), and implemented, by the driven unit (AE) and / or by the at least one rail vehicle (WA).

4. The method as claimed in one of the preceding claims, in which the counterforce (DAK-AE) is superimposed on the motive force (AK-AE) as a time characteristic.

5. The method as claimed in one of the preceding claims, in which the counterforce (DAK-AE) is determined and / or superimposed and / or implemented in the train (ZG) in an automated manner.

6. The method as claimed in one of the preceding claims, in which the algorithm (ALG) is tailored to an operating behavior ofthe driven unit (AE) in order to take into account previously known time delays in the counterforce implementation in the train (ZG).

7. The method as claimed in one of the preceding claims, in which the sensor used is an acceleration sensor.

8. The method as claimed in one of the preceding claims, in which the sensor (SEN) used is a sensor (SEN)- that is arranged close to or on the driven unit (AE), or- that is arranged close to or on a coupling (KUP) that connectsthe driven unit (AE) to the rail vehicle (WA), or- that is arranged close to or on a coupling (KUP) that connectstwo adjacent rail vehicles (WA) of the train (ZG) to oneanother.

9. The method as claimed in one of the preceding claims, in which the driven unit (AE) used is a locomotive or a railcar or a driven wheelset or a driven bogie.

10. A train comprising means designed to carry out the method as claimed in one of claims 1 to 9.

11. The train as claimed in claim 10,- in which the train (ZG) comprises at least one driven unit (AE) and at least one rail vehicle (WA) connected thereto,- in which the train (ZG) comprises motive force means that apply a motive force (AK-AE) to the train (ZG) in order to drive the train (ZG) in a deliberate manner or in order to slow the train (ZG) in a deliberate manner,- in which the train (ZG) comprises a detection means designed to detect a longitudinal vibration (LS) arising for the train (ZG),- in which the train (ZG) comprises a means for determining a time characteristic (t(LS)) of the longitudinal vibration (LS),- in which the train (ZG) comprises an algorithm (ALG) to which the time characteristic (t(LS)) of the longitudinal vibration (LS) is fed,- in which the algorithm (ALG) is designed to determine acounterforce (DAK-AE) so that the counterforce (DAK-AE), when superimposed on the motive force (AK-AE), causes the longitudinal vibration (LS) to be absorbed, and- in which the train (ZG) comprises a means for implementing the counterforce (DAK-AE) so that the longitudinal vibration in the train is reduced.

12. The train as claimed in claim 11, in which the detection means and / or the means for determining the time characteristic (t(LS)) of the longitudinal vibration (LS) is a sensor (SEN), in particular an acceleration sensor.

13. The train as claimed in claim 12, in which the sensor (SEN)- is arranged close to or on the driven unit (AE), or- is arranged close to or on a coupling (KUP) that connects the driven unit (AE) to the rail vehicle (WA), or- is arranged close to or on a coupling (KUP) that connects two adjacent rail vehicles (WA) of the train (ZG) to one another.

14. The train as claimed in claim 11, in which the algorithm (ALG) is tailored to an operating behavior of the driven unit (AE) in order to take into account previously known time delays in the counterforce implementation in the train (ZG).

15. The train as claimed in claim 11, in which the driven unit (AE) is a locomotive or a railcar or a driven wheelset or a driven bogie.

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