DEVICE AND METHOD FOR DETECTING RAILWAY EQUIPMENT DEFECTS
20210403060 · 2021-12-30
Assignee
Inventors
Cpc classification
B61L25/025
PERFORMING OPERATIONS; TRANSPORTING
B61L23/04
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
A device for detecting railway equipment defects, comprising at least three diagnostic modules mounted on a generic railway vehicle: a first module (geometrical module) configured to measure at least a geometrical feature of the track; a second module (acceleration module) configured to measure in at least a point of said vehicle the side and/or vertical accelerations transmitted from the track to said vehicle; a third module (visual module) configured to acquire the images of the track elements and to analyze them to verify the presence of anomalies;
said modules being configured to associate with each detection carried out when the railway vehicle passes, on which they are mounted, the position where the detection was carried out and to calculate, for each detection, a severity index representative of the deviation of the detection with respect to the standard condition without defects.
Claims
1. A device for detecting railway equipment defects, comprising: at least three diagnostic modules mounted on a generic railway vehicle, of which: a first module (geometrical module) is configured to measure at least a geometrical parameters of the railway; a second module (acceleration module) is configured to measure in at least a point of said vehicle the lateral and/or vertical accelerations transmitted from the railway to said vehicle; a third module (visual module) is configured to acquire images of railway elements and to analyze them to verify the presence of visual anomalies; means for detecting the position of the railway vehicle; electronical means configured to acquire data detected by said diagnostic modules and to calculate, for each detection carried out by each module, a severity index representative of the deviation of the detection with respect to the standard condition of the railway without defects, wherein said electronic means are configured to: a) calculating for each detection of each module an initial severity index (h1) indicative of the amplitude of the deviation of the detection with respect to the standard condition without defects; b) associating to each initial severity index (h1) a parameter (d1) indicative of the kind of potential defect; c) associating each initial severity index (h1) and respective parameter (d1) indicative of the kind of potential defect with their acquisition position (xi), thus defining a potential defect characterized by: a position (xi), a kind parameter (di) and an initial severity index (h1); d) calculating for each potential defect defined in point c) a global severity index (ht), as a function of said parameter (di) indicative of the kind, of said initial severity index (h1), and of the relative distances (xij) with respect to other detected potential defects, of their kind parameters and of their initial severity index; d) comparing said global severity index (ht) with a critical threshold to determine if said potential defect needs a maintenance operation or not.
2. The device for detecting railway equipment defects according to claim 1, wherein said global severity index (ht) is given by the sum of: said initial severity index (hi) and of a contribution relative to each potential defect detected in a predefined area close to said position (xi) of said defect for which the global severity index (ht) is calculated.
3. The device for detecting railway equipment defects according to claim 2, wherein said contribution relative to each potential defect (hj) detected in a predefined area close to said detection position (xi) of said defect for which the global severity index (ht) is calculated is given by the product of the severity index (hj) of said potential defect multiplied by a term which is a function of the relative distance of said two defects (xij) and of said kind parameters of the two defects (di, dj).
4. The device for detecting railway equipment defects according to claim 3, wherein said term function of the relative distance of said two defects (xij) and of said kind parameters of the two defects (di, dj) is calculated as negative exponential of the ratio between the distance of the two defects (xij) and an amplification coefficient (aij), function of said kind parameters of the two defects.
5. The device for detecting railway equipment defects according to claim 1, wherein said critical threshold depends on said kind parameter.
6. The device for detecting railway equipment defects according to claim 2, wherein a width of said predefined area is 1 km.
7. The device for detecting railway equipment defects according to claim 1, wherein said geometrical parameters comprise at least a parameter selected from the group consisting of rail gauge, superelevation, alignment, longitudinal level, track twist or any other parameter derived from geometrical measures on the rail.
8. The device for detecting railway equipment defects according to claim 1, wherein said visual anomalies detected by means of said visual module comprise at least an anomaly selected among: absence or anomaly of couplings, joints anomaly, insufficient quantity of crushed stone, absence or loosening of sleeper screws for sleepers and track bolts for joints, presence of fractures on sleepers and rails or any other morphological anomaly of the elements constituting the equipment.
Description
DETAILED DESCRIPTION OF THE INVENTION
[0032] According to a preferred embodiment, the system according to the present invention comprises at least three diagnostic modules mounted on a generic railway vehicle: [0033] a first module, called geometrical module, dedicated to measuring track geometrical parameters (rail gauge, superelevation, alignment, longitudinal level, track twist or any other parameter derived from geometrical measures on track); [0034] a second module, called acceleration module, dedicated to measuring side and vertical accelerations transmitted from track to measuring vehicle; [0035] a third module, called visual module, configured to acquire images of the track elements and to analyze them automatically to detect visual defects, for example absence or anomalies of couplings, joints anomalies, insufficient quantity of crushed stones, absence or loosening of sleeper screws for sleepers and track blots for joints.
[0036] The three modules are configured to associate with each detection of a potential defect carried out when the railway vehicle passes, on which they are mounted, the position where such detection was carried out. This association can be carried out by means of a GPS signal and/or an odometer.
[0037] The three modules are also configured to calculate, for each detection, an index representative of the deviation of the detection with respect to the standard condition without defects, in the following also called severity index (hi).
[0038] The diagnostic method for detecting railway equipment defects which can be applied with the device according to the present invention comprises the following steps of:
a) measuring geometrical, accelerometric and visual parameters at the same time, by means of the just described three diagnostic modules;
b) evaluation of the severity index calculated for all the detections, in order to detect potential defects, by associating with each potential defect the position where it was detected;
c) comparison of said severity index with at least a predetermined critical threshold for defect kind.
[0039] The method is characterized in that it further comprises:
e) another analysis for
(i) verifying the detected defect, thus excluding that it is a false positive;
(ii) determining the cause of the defect;
(iii) verifying if a defect, even if the severity index is lower than the threshold of step d), is to be considered dangerous since it is close to other defects.
[0040] As a function of the results of the analysis of point e), therefore, it is possible to determine the kind of maintenance to be carried out to restore the normal conditions of the equipment in a more efficient and exact way with respect to the known systems.
EXAMPLES OF APPLICATION
[0041] In the following, some examples of application of the just described method are reported for clarity's sake.
[0042] A partial deterioration of an isolated joint determines a localized yielding of the rail under load, which causes an anomalous acceleration of the vehicle. In such condition, the geometrical module detects a level defect (gap between rail height and surrounding rolling plane), while the acceleration module detects an anomalous vertical acceleration at the vehicle axles. The visual module, at the same measuring section, recognizes the presence of a joint and detects there a fracture which reduced its structural stiffness.
[0043] The concomitance of these three detections (geometrical, accelerometric, visual) allows to verify the defect, thus excluding that it is a false positive.
[0044] This redundancy, i.e. the presence of systems measuring many physical aspects, allows a cross check of the defect detection which reduces the error probability, thus allowing a global evaluation of the risk condition, a reduction of false positives, and the determination of the cause determining the defect.
[0045] On the basis of the information provided by the system, from the point of view of the maintenance operator, it is clear that the joint is to be repaired or changed, and the correct maintenance operation allows to plan the maintenance operation in a more efficient and economical way, thus avoiding the worsening of the detected condition. In fact, anomalous yielding of the joint leads to high accelerations transmitted from vehicle to track; such accelerations cause ballast yielding, thus further increasing the joint inflection.
[0046] If the system detects in the same measuring section absence of crushed stone as well, the maintenance operator will know in advance, i.e. before going physically on place, that in addition to the substitution of the joint, it is to be restored also the ballast original profile.
[0047] The further analysis, which can be carried out with the system according to the invention, provided with the information about defects presence, kind, severity and position, is the definition of an index which, in addition to the single defect severity, considers also their mutual position.
[0048] It is to be indicated with: [0049] d.sub.1, d.sub.2, . . . , d.sub.3 a number n of consecutive defects, each one of any different kind, detected by the running railway vehicle; [0050] x.sub.12, x.sub.13, x.sub.14, . . . , the distance between a defect and the following ones in running direction; [0051] h.sub.1, h.sub.2, . . . , h.sub.n the severity index of each defect considered isolated.
[0052] It is to be specified that the parameter “d” contains a coding of the defect kind.
[0053] The method according to the present invention, in order to carry out an analysis of the synergic action of many isolated defects, provides the calculation of a global severity index h.sub.t of the detected defects, as a function of the kind and severity of each defect, as well as of its relative distance with respect to the other defects.
h.sub.t=F(d.sub.i,h.sub.i,x.sub.ij) (1)
[0054] According to a first embodiment, the function F is a linear or not linear combination of the parameters; according to another embodiment the function F is a Fuzzy logarithm or any other mathematical function which allows to combine efficiently the defects synergic effect.
[0055] As a way of example, assuming that a defect d.sub.1 was detected with severity index h.sub.1, and assuming also that a second defect d.sub.2 was detected with severity index h.sub.2 at distance x.sub.12 from the first defect, a possible mathematical function calculating the total severity index of the two aggregated defects is the following:
[0056] The term in parenthesis is a decreasing exponential function which weighs the contribution of defect d.sub.2 aggregated to defect d.sub.1. If the two defects are present in the same track section, their inter-distance x.sub.12 is equal to zero, and so the term in parenthesis is equal to 1.
[0057] Therefore, the effect of defect d.sub.2 aggregated to defect d.sub.1 is considered completely in the calculation of the combined severity index h.sub.t. While the inter-distance increases, the exponential reduces to zero as faster as lower the amplification coefficient a.sub.12 is. This coefficient quantifies the synergic effect of the distance between two aggregated defects; therefore, it will be higher when the synergic effect of the second defect vanishes rapidly with the distance.
[0058] As a way of merely indicative and not limiting example, in the following it is described an embodiment of the method. Let's assume to evaluate the severity index (h.sub.1) of a defect according to a scale from 1 to 5, in which: [0059] value 1 of the index corresponds to a moderate defect which does not require any specific action other than to monitor its evolution in time; [0060] value 2 corresponds to the need of a maintenance operation in three months; [0061] value 3 corresponds to the need of a maintenance operation in a week; [0062] value 4 corresponds to the need of a maintenance operation in a day; [0063] value 5 corresponds to a very severe defect which requires the suspension of the train circulation and the immediate elimination of the defect.
[0064] It is to be considered now the rail gauge measure, whose nominal value is 1435 mm. According to the just described logic, when the system measures in a determined point of the track a rail gauge value equal to 1440 mmm it generates a defect with severity index equal to h.sub.1=1, since a deviation of 5 mm is not considered severe with respect to the nominal measure. In order to explain better the logic, if in the same point a rail gauge value equal to 1465 mm is measured, the same defect would be assigned a value equal to 4 of the severity index, which would require a maintenance operation in 24 hours.
[0065] Let's assume now that at a distance x.sub.12=0.5 m with respect to the point where it was generated the defect with severity index equal to 1, the visual system detects the absence of both bolts on inner and outer couplings of the right rail.
[0066] This second defect, taken singularly, is assigned a severity index h.sub.2=2, which means a maintenance operation in three months. However, the close distance between the two defects allows to foresee a possible increase in rail gauge in short time, owing to the absence of two bolts on the right rail, but this defects evolution, even if technically foreseeable, is not signaled by the detection systems known at the state of the art, which consider the defects singularly. Therefore, in case of using one of any system known at the state of the art, maintenance operations would be undertaken in three months, thus allowing the rail gauge defect to evolve towards a condition of greater risk for circulation.
[0067] The system according to the present invention instead, by providing the calculation of the total severity index according to what previously explained, even in presence of defects, which are not considered severe singularly, indicates the need of a more imminent maintenance operation.
[0068] In fact, by assuming an amplification ratio a.sub.12=2 for combined presence of a defect kind d.sub.1=rail gauge defect and a defect kind d.sub.2=absence of couplings, the calculation of the total severity index would be obtained with the yet reported formula (2), which, in this case, would give the following value:
[0069] The calculated value h.sub.t, since it is greater than 2.5, is rounded up to 3, and so, according to the just described severity scale, is it determined the need for a maintenance operation in a week.
[0070] Therefore, it is observed as the presence of two close defects which, taken singularly, would indicate the need of a maintenance operation in three months, is detected by the system according to the present invention as a defect which requires a maintenance operation in a week.
[0071] In the case of the just explained example, this reduces drastically the evolution of rail gauge defect. However, it is clear that what just described is only an example of the method according to the invention, and that different numerical values can be assigned to amplification factors or to severity indexes, without departing from the aims of the invention.