Method and device for approximating an acceleration signal profile recorded when a rail-bound vehicle crosses a measuring section to the characteristic features of a corresponding force signal profile.

Abstract

Method for approximating an acceleration signal profile a(t) recorded when a rail-bound vehicle passes over a measuring section (1, 1', 1'') to the characteristic features of a corresponding force signal profile F(t), wherein the measuring section (1, 1', 1'') is designed as a rail (3) and has at least one acceleration sensor (11), whose acceleration signals a are transmitted to an electronic evaluation unit (13) for reception and processing, comprising the following method steps: a) Continuous recording of the acceleration a exerted on the rail by a rolling wheel using the at least one acceleration sensor (11); b) Determining the acceleration signal profile a(t) as a result of the wheel contact force F acting on the measuring section (1, 1', 1'') when the vehicle passes over it.c) Filtering the acceleration signal profile a(t) determined in step b) with a high-pass filter and a low-pass filter or a band-pass filter, and d) Numerical integration of the acceleration signal profile a'(t) obtained by filtering in step c).

Description

field of technology

[0001] The invention relates to a method for approximating an acceleration signal profile a(t) recorded when a rail-bound vehicle crosses a measuring track to the characteristic features of a corresponding force signal profile F(t) according to the preamble of claim 1, and to a device for carrying out the method according to the preamble of claim 7. State of the art

[0002] The treads of the wheels of rail vehicles are of crucial importance for ride comfort and the safety of rail transport, as the static and dynamic forces generated during travel are transferred to the rails via the treads and wheel flanges. Ideally, the geometry of the treads corresponds to a slightly conical surface concentrically circumferentially around the wheel axle, with which the wheels roll on the rails. The treads thus form the rotating part of the wheel-rail contact. Deviations from the ideal circular shape, for example, caused by uneven wear, material and manufacturing defects, and the like, are referred to as out-of-roundness. These include singular out-of-roundness such as flat spots, flattening, and material build-up, as well as periodic out-of-roundness such as eccentricities, ovalities, and polygonal shapes.Especially at high speeds, wheel out-of-roundness increases the dynamic component of the forces exerted by the wheels on the rail. Consequently, there is a risk that the limits for peak forces specified by the track operator will be exceeded, potentially damaging the track and rolling stock. Further negative impacts include safety risks, noise emissions, and vibrations of the track bed.

[0003] Therefore, there has been no shortage of efforts to identify wheels of a rail vehicle affected by out-of-roundness as early as possible. Besides manually measuring the geometry of a wheel using gauges on the stationary vehicle, which is particularly suitable for carrying out other maintenance and repair work due to the associated time expenditure, it is also already known to detect out-of-roundness on a wheel while the rail vehicle is passing over a measuring track equipped with sensors.

[0004] A method and device for detecting out-of-roundness and flat spots on the wheels of railway vehicles are already known from EP 1 212 228 B1. In this method, several force transducers are used to measure the vertical forces acting on the rails within a predetermined measuring section. The force transducers are designed as load cells, which are arranged between the rails and fixed sleepers over a length of at least the circumference of the wheel. As the vehicle traverses the measuring section, an electronic evaluation unit calculates an average weight load from the vertical force signals and compares this with the signal over time. If a predetermined deviation is exceeded, an out-of-roundness or flat spot is indicated. In this way, out-of-roundness and flat spots can be detected very reliably.However, since the detection is based on a force signal profile, this method involves relatively high investments for the construction of the measuring section due to the necessary force sensors.

[0005] EP 0 282 615 A1 describes an arrangement for detecting wheel damage using linear accelerometers extending along a rail. These linear accelerometers measure the acceleration transmitted from the wheel to the rail at any given point along their length. The individual measurement signals obtained in this way are subjected to an evaluation procedure to determine the extent of wheel damage. This involves filtering out characteristics from the measurement signal using suitable frequency filter stages and / or FFT analysis, providing information about the type and severity of the wheel damage. The disadvantage of this method is that it only provides a rough measurement result. Furthermore, it does not allow for conclusions to be drawn about the level of stress on the track during a train crossing it.

[0006] Furthermore, EP 1 883 565 A1 discloses a method for detecting the wheel shapes of railway vehicles' wheels using a measuring section formed by a series of measuring elements attached to the rails. The wheel loads acting on the measuring elements generate force-proportional electrical signals, which are fed to an electronic evaluation unit for analysis. In the evaluation unit, an information array is generated from the signals derived from the measuring elements, which correspond to the movement of the rail in the vertical direction and preferably also in the transverse direction. This information array represents at least one wheel circumference. The information array consists of several information cells, whereby the respective signal components of different information cells can be continuously combined and relevant signal components are evaluated. Brief summary of the invention

[0007] Based on this prior art, the invention aims to provide a method and a device with which the out-of-roundness of a wheel of a rail-bound vehicle can be reliably and accurately determined in an economical manner. A further objective of the invention is to be able to derive quantitative statements about the underlying wheel loads from an existing acceleration signal profile.

[0008] These problems are solved by a method having the features of claim 1 and a device having the features of claim 7.

[0009] Advantageous embodiments are described in the dependent claims.

[0010] The invention is based on the idea of ​​drawing conclusions about the corresponding force signal F(t) from the acceleration signal profile a(t), which is recorded when a rail vehicle passes over a measuring section, without having to additionally record the force signal. The corresponding force signal profile F(t) is defined as the force signal profile F(t), which is unknown or only partially known, but which is the cause of, and thus the basis for, the recorded acceleration signal profile a(t).

[0011] Since more precise information about the mass-spring system formed by the track superstructure, substructure, and rail vehicle is generally unavailable, a purely mathematical conversion of the acceleration signal curve a(t) to the corresponding force signal curve F(t) is not possible. The merit of the invention lies in providing a solution for approximating the force signal curve F(t) from the associated acceleration signal curve a(t), even without knowledge of this information.

[0012] The solution according to the invention provides to filter the acceleration signal profile a(t) recorded by means of a measuring section, whereby signal components below a lower cutoff frequency f are excluded. L and above an upper cutoff frequency f HThe signal is blocked or strongly attenuated. Filtering both aligns the acceleration signal a(t) with the measurement technology and prepares it for numerical integration. For this purpose, a device according to the invention comprises suitable low-pass and high-pass filters or a corresponding band-pass filter.

[0013] For further approximation, the acceleration signal profile a'(t) obtained in this way is numerically integrated, which can be carried out using electronic data processing in a suitable evaluation unit. After completion of the numerical integration, the acceleration signal profile a''(t) is so closely approximated to the corresponding force signal profile F(t) that sufficiently qualified statements can be made about the wear condition and the need for repair of a wheel. For example, above-average maximum and minimum values ​​in the amplitude of the numerically integrated acceleration signal profile a''(t) can indicate wheel out-of-roundness, or, based on consistent repetitions in the acceleration signal profile a(t), conclusions can be drawn about the actual circumference of a wheel and thus its wear condition.

[0014] A particular advantage of evaluating the acceleration signal profile a''(t) obtained according to the invention is that known and proven algorithms for evaluating force signals can be used. This eliminates the need for additional effort in developing and testing suitable software.

[0015] Since measuring sections equipped with force transducers require significantly higher investments than measuring sections with accelerometers, the invention presents itself as a particularly interesting alternative from an economic perspective, especially for operators of railway systems.

[0016] To prevent damage to track systems, compliance with limit values ​​for wheel contact forces F is of great importance. In order to derive quantitative statements about the existing wheel contact forces F from the integrated acceleration signal curve a''(t), an advantageous further development of the invention involves calibrating the acceleration signal curve a''(t) based on known wheel contact forces F. According to a preferred embodiment of the invention, this can be achieved by scaling the acceleration signal curve a''(t) by multiplying the individual values ​​of the acceleration signal curve a''(t) by a uniform factor k and thus adapting them to the force signal curve F(t).

[0017] The factor k can be stored as a fixed value for a specific rail vehicle type in the evaluation unit. Alternatively, it is possible to determine the factor k as the rail vehicle traverses the measuring section, thereby increasing the accuracy of the approximation of the integrated acceleration signal profile a''(t). For this to work, at least part of the measuring section must be equipped with force sensors that record the corresponding force signal profile F(t) during or after the acquisition of the acceleration signal profile a(t). Corresponding individual values ​​or segments of the two signal profiles a''(t) and F(t) can then be compared, allowing the factor k to be determined according to the following relationship: k=a'' / F or k=a''(t) / F(t)

[0018] A suitable measuring section is advantageously divided into a first section equipped with force sensors and a second section with accelerometers. The first and second sections can overlap, for example, by extending the second section with the accelerometers over the entire length of the measuring section, while the second, shorter section covers only a longitudinal segment. In this embodiment of the invention, the acceleration signal a and the force signal F are recorded simultaneously, allowing for subsequent calibration of the integrated acceleration signal profile a(t) based on the actual wheel contact forces. This approach allows for the derivation of exceptionally reliable values ​​for the wheel contact force F from the acceleration signal profile a(t) obtained through numerical integration.

[0019] In another embodiment of the invention, the first and second measuring sections follow one another in the direction of the rail track. Since both measuring sections are shorter than the total measuring section, the full length of the measuring section is only obtained by combining the two sections. This embodiment is particularly suitable when a measuring section with force transducers for determining wheel contact forces is already present, and its functionality is to be extended to include the condition of the wheels of a rail vehicle. However, new measuring sections can also be implemented economically using this embodiment of the invention.

[0020] Without limiting ourselves to this, the invention will below be explained in more detail with reference to exemplary embodiments illustrated in the drawings, whereby further features and advantages of the invention will become apparent. Where possible, identical reference numerals are used for identical and functionally equivalent features of different embodiments. Brief description of the drawings

[0021] It shows Fig. 1 an oblique view of a first embodiment of a device according to the invention for carrying out a method according to the invention, Fig. 2 the temporal course of the process with the device according to Fig. 1 detected acceleration signal a, Fig. 3 an oblique view of a second embodiment of a device according to the invention for carrying out a method according to the invention, Fig. 4a the temporal course of the process with the device according to Fig. 3 recorded force signal F, Fig. 4b the temporal course of the process with the device according to Fig. 3 detected acceleration signal a, Fig. 5 an oblique view of a third embodiment of a device according to the invention for carrying out a method according to the invention, Fig. 6a the temporal course of the process with the device according to Fig. 5 recorded force signal F, Fig. 6b the temporal course of the process with the device according to Fig. 5 detected acceleration signal a, and Fig. 7 the temporal course of an acceleration signal a, a', a'' at different times during the execution of the method according to the invention in comparison with the corresponding force signal course F. Description of the embodiments

[0022] Fig. Figure 1 shows a first embodiment of a device according to the invention for carrying out the method according to the invention, with a measuring section 1 for recording and evaluating the acceleration a that occurs during the passage of a rail-bound vehicle over the measuring section 1. In a simplified representation, a section of a rail track 2, designed as a measuring section 1, is shown, comprising two parallel rails 3 supported by a plurality of sleepers 4. The distance between the sleepers 4 is in the range of approximately 600 mm to 700 mm. The rail track 2 is traversed by a rail-bound vehicle at a speed v, for example, a passenger or freight car, for which only the wheels 5 of a wheelset axle (not shown) are depicted as a representative example.The direction of travel of the rail-bound vehicle is denoted by x, the wheel force exerted by a wheel 5 on a rail 3 by F.

[0023] The measuring section 1 extends over a length L which, in the present embodiment, corresponds to at least 1.2 times the wheel circumference U of the wheels 5 of the vehicles traveling on the rail track 2, preferably 1.5 times, and most preferably 2 times. With a standard wheel diameter of approximately 1250 mm, this results in a length L of at least 4710 mm, preferably at least 5888 mm, and most preferably 7850 mm.

[0024] In the area of ​​measuring section 1, a measuring device for recording the acceleration a exerted on the rail 3 by a rolling wheel 5 is integrated into the rail track 2. The measuring device initially comprises two transverse force sensors 6, 7 arranged on each rail 3, one of which is installed at the beginning and the other at the end of measuring section 1. These sensors are, for example, measuring eyes or strain gauges that detect the shear stresses induced in the rails 3 by the wheels 5 in an analog manner and convert them into digital measurement signals. In this embodiment, the transverse force sensors 6, 7 serve for the optional determination of the wheel contact forces. Furthermore, the transverse force sensors 6, 7 can be used as switches for the start and end of the measuring process of the measuring device and / or for axle detection and vehicle identification. Additionally, as described below... Fig. 2. In more detail, the driving speed v in the area of ​​the measuring section 1 is determined using the transverse force sensors 6, 7, which can be determined on the basis of the known distance of the transverse force sensor 6 from the transverse force sensor 7 in the direction of travel x and the known time period T, which is the difference of the rolling times t. A and t E corresponds.

[0025] Furthermore, the measuring device includes accelerometers 11 for recording the acceleration a. The accelerometers 11 are each attached between two sleepers 4 on the underside of the rails 3, resulting in a mutual distance of the accelerometers 11 in the direction of the track 2, which corresponds to the single sleeper spacing, but can also be larger and, for example, correspond to twice the sleeper spacing.

[0026] The transverse force transducers 6, 7 and the accelerometer 11 are connected via data lines 12 to an electronic evaluation unit 13, in which data storage and processing take place. To carry out the method according to the invention, the evaluation unit 13 can, for example, have high-pass, low-pass, and / or bandpass filters to filter the acceleration signal, and / or computational algorithms are executed in the evaluation unit 13 by means of which a numerical integration of the acceleration profile a(t) is performed. The data of a measurement process or the results of the evaluation are transmitted to a higher-level central unit via radio or a further data line 14. It is also possible to carry out the data processing partially or completely at the higher-level central unit.

[0027] In Fig. Figure 2 shows the time course of the acceleration signal a measured by the accelerometers 11 during the crossing of the measuring section 1. The point at which the wheel 5 passes over the lateral force sensor 6 corresponds to time t. A , at which the measurement process by the measuring device begins. The passing of the lateral force sensor 7 by the same wheel 5 defines the time t. E , which defines the end of the measurement process. The interval between time points t A and t E The horizontal time interval T corresponds to the duration of the crossing over the measuring section 1. If the spatial distance between the transverse force sensors 6, 7 is known, which in the present embodiment corresponds to the length L of the measuring section 1, the travel speed v of the rail vehicle can be determined according to the following relationship: v=L / T with T=(tE−tA)

[0028] The amplitude of the acceleration signal a oscillates around zero at a high frequency, depending on the quality of the wheel 5's running surface. Significant deviations from this range represent the first acceleration maximum 16 and the first acceleration minimum 17 of the acceleration signal curve a(t), indicating a non-roundness on the wheel 5's running surface. The time of the first occurrence of the first acceleration maximum 16 and the first acceleration minimum 17 is denoted by t1.

[0029] Due to the predetermined length L of measuring section 1, which is greater than the wheel circumference U, the wheel 5 rolls at least a portion of its circumference U a second time within measuring section 1 during the ongoing measurement process. This renewed rolling of the wheel 5 on the rail 3 generates an acceleration signal profile a(t) whose characteristic features correspond to those of the previous acceleration signal profile a(t). The most noticeable repetition is the second acceleration maximum 16' or second acceleration minimum 17' at time t2, which, based on their amplitude and shape, can be assigned to the first acceleration maximum 16 and first acceleration minimum 17, respectively. The time interval Δt between times t1 and t2 corresponds to the time it takes for the wheel 5 to roll once over its circumference U. In conjunction with the known travel speed v, the circumference U of the wheel 5 can be determined from this using the following relationship: U=v*Δt with Δt=t2−t1

[0030] The acceleration signal profile a(t) recorded by the measuring device forms the basis for carrying out the method according to the invention, in which the acceleration signal profile a(t) is approximated to the force signal profile F(t) underlying the acceleration signal profile a(t), which is described in detail below. Fig. 7 will be explained in more detail.

[0031] A second embodiment of a device according to the invention is the subject of Fig. 3, Fig. 4a and Fig. 4b. The in Fig. The measuring section 1' shown in section 3 corresponds to the one shown below. Fig. The measuring section 1 described above is supplemented by a partial measuring section 1.1 for recording the wheel contact force F in the area of ​​the partial measuring section 1.1. To avoid repetition, reference is made to the above statements regarding the rail track 2, the measuring section 1' with transverse force sensors 6, 7, acceleration sensors 11, data lines 12, evaluation unit 13 etc., which apply accordingly.

[0032] The partial measuring section 1.1 extends over a length L1, which is shorter than the length L of the measuring section 1' and, in the present embodiment, corresponds at least to the single wheel circumference U of the wheels 5 of the vehicles traveling on the rail track 2. With a standard wheel diameter of approximately 1250 mm, this results in a length of at least 2925 mm.

[0033] The measuring section 1' and sub-measuring section 1.1 overlap in the direction of travel x, sharing a common beginning defined by the lateral force sensors 6. The first sub-measuring section 1.1 ends after length L1 at the lateral force sensors 8, while the measuring section 1' continues to the lateral force sensors 7, which mark the end of the measuring section 1'.

[0034] In the area of ​​the partial measuring section 1.1, the measuring device also includes shear force transducers arranged on the rails 3. These transducers can correspond to shear force transducers 6 at the beginning of the partial measuring section 1.1 and to shear force transducer 8 installed at the end of the partial measuring section 1.1. Additional shear force transducers 9 can be arranged between them, their mutual spacing corresponding, for example, to one or two times the sleeper spacing. As previously described, the shear force transducers 6, 8, 9 are preferably measuring eyes or strain gauges that detect the shear stresses induced by the wheels 5 into the rails 3 analogously and convert them into digital measurement signals.

[0035] Like the transverse force sensors 6 and 7, the transverse force sensors 8 and 9 serve for force shunt correction to compensate for disturbances from adjacent rail sections. In this way, the partial measuring section 1.1 is segmented into smaller measuring sections. The transverse force sensors 6, 7, 8, and 9 can also be used to determine the wheel contact force F.

[0036] Furthermore, force transducers 10 are provided in the area of ​​the first partial measuring section 1.1 for detecting the wheel contact force F, for example, load beams, load cells, or load discs. In order to obtain a force signal that is as uniform as possible over the length of the partial measuring section 1.1, in the present embodiment a force transducer 10 is arranged between each sleeper 4 and each rail 3, resulting in a mutual spacing of the force transducers 10 in the direction of the track 2 corresponding to the single sleeper spacing. In addition, embodiments within the scope of the invention are also included in which the spacing of successive force transducers 10 in the direction of travel x corresponds to two or three times the sleeper spacing.

[0037] As already described in the first embodiment, the transverse force transducers 6, 7, 8, 9 and the force transducers 10 are connected via the data lines 12 to an electronic evaluation unit 13, in which data storage and processing take place. The data of a measurement process and, if applicable, its evaluation are transmitted to a higher-level central unit via radio or a further data line 14.

[0038] As from the Fig. 4a and Fig. As can be seen from 4b, it begins at time t A Simultaneously, both the wheel contact force F is detected by means of the force sensors 10 and the acceleration a is detected by means of the acceleration sensors 11. Accordingly, in this embodiment of the invention, the force signal profile F(t) over the length L1 is recorded simultaneously with the acceleration signal profile a(t).

[0039] Fig. Figure 4a shows the time course of the force signal F measured by force transducers 10 during the crossing of the partial measuring section 1.1, which begins with the wheel 5 rolling over the lateral force transducer 6 and ends at time tx, when the wheel 5 rolls over the lateral force transducer 8 and thus leaves the area of ​​the first partial measuring section 1.1.

[0040] The amplitude of the force signal F oscillates more or less strongly around a value corresponding to the static load component F, depending on the quality of the wheel's running surface 5. stat The force F exerted by a wheel 5 on a rail 3 corresponds to the force F. Significant deviations from the fluctuation range are represented by the force maximum 14 and force minimum 15 at time t1, which, due to their slope and amplitude, indicate an out-of-roundness on the running surface of the wheel 5.

[0041] The acceleration signal curve a(t) as in Fig. 4b shown corresponds to the one under Fig. As described in section 2, reference is made to what has been said there to avoid repetition. It should be noted that an out-of-roundness on the running surface of a wheel 5 at the same time t1 leads to maximum values ​​14, 15 in the force signal curve F(t) and to maximum values ​​16, 17 in the acceleration signal curve a(t).

[0042] In this embodiment of the invention, the acceleration signal profile a(t) recorded by the measuring device is approximated to the force signal profile F(t) underlying the acceleration signal profile a(t) by combining the acceleration signal profile a(t) with the force signal profile F(t), as detailed in the description of Fig. 7 will be explained in more detail.

[0043] The Fig. 5 and Fig. Figure 6 finally shows an embodiment of the invention in which the measuring section 1" in the direction of the rail track 2 is composed of a first partial measuring section 1.1 of length L1 and a second partial measuring section 1.2 of length L2, which merge seamlessly into one another in the direction of travel x. The first partial measuring section 1.1 with force transducers 10 corresponds to the one described below. Fig. 3 described, so that the statements therein apply accordingly.

[0044] The second measuring section 1.2 with the accelerometers 11 has a design that is basically the same as described below. Fig. The measuring section 1 described in section 1 is identical, so that what is stated there applies accordingly. However, a significant difference is that the length L2 of the second partial measuring section 1.2 is considerably smaller than the length L of measuring section 1.2. The length L2 of the second partial measuring section 1.2 can be smaller than the length L1 of the first partial measuring section 1.1, as in the present embodiment, or it can be larger than the length L1 of the first partial measuring section 1.1. In both cases, the first partial measuring section 1.1 and the second partial measuring section 1.2 together constitute measuring section 1". At the beginning of measuring section 1", transverse force sensors 6 are arranged on the rails 3, and at the end of measuring section 1", transverse force sensors 7 are arranged. Additional transverse force sensors 8 are located in the transition area between the first partial measuring section 1.1 and the second partial measuring section 1.2, and optionally in the area of ​​partial measuring section 1.1, in order to measure it as before. Fig. to divide it into 3 smaller sections.

[0045] When a rail vehicle crosses the measuring section 1", in the area of ​​the first partial measuring section 1.1 from time t A A force signal profile F(t) over the length L1 was recorded, for which, as already mentioned below... Fig. 4a describes the force maximum 14 and force minimum 15 as characteristic. These occur at time t when the end of the first partial measuring section 1.1 and the beginning of the second partial measuring section 1.2 are reached during the rolling over of the transverse force sensors 8. X The acquisition of the acceleration signal a begins over the length L2 of the second partial measuring section 1.2, which is in Fig. The acceleration profile a(t) shown in Figure 6b, with acceleration maxima 16 and acceleration minima 17, is obtained. The measurement process ends when the wheels 5 pass over the lateral force sensors 7 at the end of the measuring section 1".

[0046] For the evaluation of the combined force / acceleration profile, the acceleration signal profile a(t) is approximated to the force signal profile F(t) underlying the acceleration profile a(t) using the method according to the invention, which is subsequently demonstrated using Fig. Section 7 is explained in more detail. The result is a continuous force signal curve F(t) that can be used for further analysis.

[0047] Based on Fig. 7. The different procedural steps for approximating the acceleration signal profile a(t) as in [reference] are described below. Fig. 7a is illustrated by the underlying force signal profile F(t), which in turn is the subject of Fig. 7d is the process whose course is to be replicated as closely as possible by stepwise processing of the acceleration signal curve a(t). The necessary data processing can take place wholly or partly in the evaluation unit 13, or wholly or partly at a higher-level location, to which the necessary data are transmitted for this purpose.

[0048] Fig. Figure 7a shows the acceleration signal profile a(t), as recorded, for example, by its accelerometer 11 when a rail vehicle passes over a measuring section 1, 1'. Due to the high frequency of the oscillating acceleration signal a, qualified conclusions can be drawn about the corresponding force signal profile F(t) (see Figure 7a). Fig. 7d) not readily possible. Nevertheless, unusual deviations from the average acceleration signal curve a(t) can be observed in the region of the first maximum 16 and first minimum 17 at time t1, which are attributable to a non-roundness of the wheel 5. Due to the length L of the measuring section 1, 1', which is greater than the circumference U of the wheel 5, these maximum values ​​are repeated as the maximum 16' and minimum 17' at time t2 when the wheel 5 rolls over the measuring section 1, 1' again. This applies analogously to the partial measuring section 1.2, which differs from measuring sections 1, 1' only in its shorter length L2.

[0049] In the first procedural step, the Fig. The acceleration signal waveform a(t) shown in 7a is filtered using a high-pass filter and a low-pass filter or a band-pass filter. The lower cutoff frequency f LThe frequency lies between 5 Hz and 60 Hz, preferably between 10 Hz and 30 Hz and most preferably at 15 Hz, and the upper cutoff frequency f H between 400 Hz and 800 Hz, preferably between 500 Hz and 700 Hz, and most preferably at 600 Hz. After applying the filters, the following occurs: Fig. 7b shows the acceleration signal waveform a'(t). By restricting the recorded acceleration signals a to the frequency range between the lower cutoff frequency f L upper cutoff frequency f H In the acceleration signal curve a'(t) a clear amplitude profile can be identified, which also has as characteristic features a first maximum 16 or first minimum 17 at time t1 and a second maximum 16' and second minimum 17' at time t2.

[0050] The acceleration signal profile a'(t) is then processed by numerical integration, leading to the result shown in Fig.The acceleration signal curve a''(t) shown in Figure 7c is characterized by a further approximation to the force signal curve F(t). In particular, the amplitude ratios of maximum 16, 16' to minimum 17, 17' of the acceleration signal curve a''(t) already correspond approximately to those of the force signal curve F(t). QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 1212228 B1

[0004] EP 0282615 A1

[0005] EP 1883565 A1

[0006]

Claims

[1] Method for approximating an acceleration signal profile a(t) recorded when a rail-bound vehicle passes over a measuring section (1, 1', 1") to the characteristic features of a corresponding force signal profile F(t), wherein the measuring section (1, 1', 1") is designed as a rail (3) and has at least one acceleration sensor (11) whose acceleration signals a are transmitted to an electronic evaluation unit (13) for reception and processing, comprising the following method steps: a) Determining the acceleration signal profile a(t) resulting from the wheel contact force F acting on the measuring section (1, 1', 1") during the crossing by continuously recording the acceleration a using the at least one acceleration sensor (11), b) Filtering the acceleration signal curve a(t) determined in step a) using a high-pass filter and a low-pass filter or a band-pass filter, and c) Numerical integration of the acceleration signal profile a'(t) obtained by filtering in step b). [2] Method according to claim 1, characterized by the following further procedural step: d) Scaling the acceleration profile a''(t) obtained in step c) by numerical integration by multiplication with a factor k. [3] Method according to one of claims 1 or 2, characterized by , that in step b) the cutoff frequency f L the frequency of the high-pass filter is between 5 Hz and 60 Hz, preferably between 10 Hz and 30 Hz and most preferably 15 Hz. [4] Method according to any one of claims 1 to 3, characterized by , that in step b) the cutoff frequency f H the frequency of the low-pass filter is between 400 Hz and 800 Hz, preferably between 500 Hz and 700 Hz and most preferably 600 Hz. [5] Method according to any one of claims 1 to 4, characterized by, that in step d) the factor k is determined by calibrating the acceleration signal profile a''(t) obtained by numerical integration on the basis of a corresponding force signal profile F(t) recorded by means of the measuring section (1, 1', 1"). [6] Method according to any one of claims 1 to 5, characterized by , that in step d) the factor k is determined by calibrating the acceleration signal profile a''(t) obtained by numerical integration using values ​​and / or profiles for the wheel contact force F stored in the evaluation unit (13). [7] Device for approximating an acceleration signal profile a(t) detected when a rail-bound vehicle passes over a measuring section (1, 1', 1") to the characteristic features of a corresponding force signal profile F(t), wherein the measuring section (1, 1', 1") is designed as a rail (3) and has at least one acceleration sensor (11) and an electronic evaluation unit (13), characterized by , that the electronic evaluation unit (13) is designed to, a) to determine the acceleration signal profile a(t) resulting from the wheel contact force F acting during the crossing of the measuring section (1, 1', 1") by continuously recording the acceleration a using the at least one acceleration sensor (11), b) to filter the acceleration signal curve a(t) determined under a) using a high-pass filter and a low-pass filter or a band-pass filter, and c) to numerically integrate the acceleration signal curve a'(t) obtained by filtering under b). [8] Device according to claim 7, characterized by , that the measuring section (1, 1', 1") additionally has at least one force sensor (10) for recording the wheel contact force F. [9] Device according to claim 8, characterized by , that the area of ​​the measuring section (1', 1") with the at least one acceleration sensor (11) and the area with the at least one force sensor (10) partially overlap or follow one another in the direction of travel x. [10] Device according to any one of claims 7 to 9, characterized by , that the measuring section (1, 1', 1") has a transverse force sensor (6, 7, 8, 9) or rail switch at least at its beginning and / or end.

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