JP2014232084A - Abnormal sound detection device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and inexpensively detect an abnormality of a device and the like, on the basis of travel sound of a vehicle.SOLUTION: An abnormal sound detection device 10 can easily and inexpensively detect an abnormal sound generated by abnormality of various devices and the like mounted on a railway vehicle 20, on the basis of travel sound of the railway vehicle. Namely, it is determined whether or not an abnormal sound is contained in travel sound by carrying out 1/4 octave band analysis for the travel sound, generating a feature vector having as an element sound pressure which has been subjected to moving average processing at a prescribed average time Ts for each frequency band (octave band), and then comparing the generated feature vector to a feature vector of travel sound at normal time by using one class support vector machine.

Description

  The present invention relates to an abnormal sound detection device that detects abnormal noise based on running sound data of a railway vehicle.

  Railway vehicles are regularly inspected to maintain safety. In addition, for the purpose of promptly detecting abnormalities during operation and preventing accidents in advance, technologies for monitoring the status of various devices and parts installed have been developed and put into practical use. As a state monitoring method, a method of attaching a sensor such as a temperature sensor or an acceleration sensor to each device or component to be monitored is generally used. However, since a large number of devices and parts are mounted on a railway vehicle, if a sensor is attached to each of the devices and parts, the cost becomes high and a failure of the sensor itself may be a problem.

  By the way, abnormalities in devices and parts often appear as sound. For this reason, the technique like patent document 1 is known as a state monitoring using the sound (acoustics) of the rail vehicle in driving | running | working. That is, it is a technique for detecting the wavy wear of the rail of the track on which the railway vehicle traveled by performing frequency analysis by Fourier transform on the detected sound (acoustic data).

Japanese Patent No. 4521524

  The technique of the above-mentioned patent document 1 detects a specific state such as a wave-like wear of a rail based on whether a sound unique to the state is generated. Therefore, when this technology is applied to the status monitoring of various devices mounted on a vehicle, the number and types of devices and parts to be monitored are large, and it is impossible to put it into practical use. The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to detect an abnormality of a device or the like easily and inexpensively based on a running sound of a vehicle.

The first invention for solving the above-described problems is
On the basis of running sound data collected by a sound collecting device provided at a predetermined position of the railway vehicle, an abnormal sound detecting device (for example, FIG. 6 abnormal noise detection device 10),
An analysis means for analyzing the running sound data in a 1 / M octave band (M ≧ 4) (for example, the octave analysis unit 210 in FIG. 6);
Moving average processing means (for example, feature vector calculation unit 220 in FIG. 6) that performs moving average processing on sound pressure data of each frequency band analyzed by the analysis means with a predetermined smoothing time of 2.5 seconds or more and 5 seconds or less. When,
Evaluation that evaluates whether or not the feature vector that is the data of each frequency band that has been subjected to the moving average processing corresponds to the feature vector when normal running sound data is processed by the analysis means and the moving average processing means Processing means (for example, the abnormal sound determination unit 230 in FIG. 6);
Is an abnormal sound detection device.

As another invention,
Based on traveling sound data collected by a sound collecting device provided at a predetermined position of a railway vehicle, the computer can realize a function of detecting abnormal sounds of various devices of the railway vehicle or abnormal sounds of a track that has traveled. A program,
Analyzing means for analyzing the running sound data in a 1 / M octave band (M ≧ 4);
A moving average processing means for performing a moving average process on the sound pressure data of each frequency band analyzed by the analyzing means at a predetermined smoothing time of 2.5 seconds or more and 5 seconds or less;
Evaluation that evaluates whether or not the feature vector that is the data of each frequency band that has been subjected to the moving average processing corresponds to the feature vector when normal running sound data is processed by the analysis means and the moving average processing means Processing means,
A program for causing the computer to function may be configured.

  According to this 1st invention etc., the abnormal noise of the various equipment of the said railway vehicle or the abnormal noise of the track | truck which traveled is detected based on the traveling sound data of a railway vehicle. In other words, the running sound data is analyzed in the 1 / M octave band, and it is evaluated whether or not the feature vector that is the data of each analyzed frequency band corresponds to the feature vector of the running sound data at the normal time. As a result, it is possible to monitor the status of a plurality of devices and parts in an integrated manner without installing a sensor for each device or component to be monitored, and it is possible to easily and inexpensively detect an abnormality.

Moreover, as 2nd invention, it is the abnormal sound detection device of 1st invention,
The analysis means performs analysis in a quarter octave band.
You may comprise an abnormal sound detection apparatus.

  According to the second aspect of the invention, the running sound data is analyzed in the 1/4 octave band. Therefore, it is possible to reduce the amount of calculation by reducing the amount of data to be calculated.

Moreover, as 3rd invention, it is the abnormal sound detection device of 1st or 2nd invention,
The evaluation processing means performs the evaluation by performing an evaluation operation by a one-class support vector machine in which parameters are determined based on a feature vector related to normal running sound data.
You may comprise an abnormal sound detection apparatus.

  According to the third aspect of the present invention, whether or not the feature vector of the running sound corresponds to the feature vector of the running sound at the normal time is determined based on the feature vector related to the running sound at the normal time. This is performed by an evaluation operation using a one-class support vector machine. Therefore, evaluation can be performed with a relatively small amount of calculation.

Moreover, as 4th invention, it is the abnormal noise detection device of 3rd invention,
The evaluation processing means includes
Normalization means for normalizing the evaluation value by the one-class support vector machine (for example, the abnormal sound determination unit 230 in FIG. 6);
Means for determining whether or not the normalized value satisfies a predetermined threshold condition for determining that the noise is abnormal;
Having
You may comprise an abnormal sound detection apparatus.

  According to the fourth aspect of the invention, the evaluation value by the one-class support vector machine is normalized, and it is determined whether or not the sound is abnormal depending on whether or not the normalized value satisfies the threshold condition.

Moreover, as 5th invention, it is the noise detection device of the invention of any one of 1st-4th,
Further comprising an acquisition means for acquiring a running state of the railway vehicle at the time of collecting the running sound data;
The evaluation processing means performs the evaluation by executing an evaluation calculation in which a parameter is set based on a feature vector related to running sound data in a normal state and in the obtained running state.
You may comprise an abnormal sound detection apparatus.

  According to the fifth aspect of the invention, the evaluation as to whether or not the feature vector of the running sound corresponds to the feature vector of the running sound at the normal time is the running sound at the normal time and in the same running state as the evaluation time. This is done by an evaluation operation in which parameters are determined based on the feature vector. For example, even when the motor is operating normally, the sound is different if the running state of the railway vehicle (for example, whether it is power running or regenerative braking) is different. For this reason, the feature vector of the normal running sound is prepared for each running state, and the evaluation of the feature vector corresponding to the running state when carrying out the abnormal noise detection is executed, thereby improving the accuracy of the abnormal noise detection. Can be improved.

Moreover, as 6th invention, it is the abnormal sound detection device of 5th invention,
The traveling sound data when the traveling state at the time of sound collection of the traveling sound data is not continued for the smoothing time or more is inhibited from being evaluated by the evaluation processing means, and the traveling when the traveling sound data is continued for the smoothing time or more. Causing the evaluation processing means to evaluate the sound data;
You may comprise an abnormal sound detection apparatus.

  According to the sixth aspect of the invention, it is evaluated whether or not the feature vector of the running sound corresponds to the feature vector of the running sound at the normal time, and the running state at the time of collecting the running sound continues for the smoothing time or longer. The running sound when there is not is suppressed, and only the running sound when it lasts for more than the smoothing time is performed. Thereby, since the traveling sound in which the traveling state has changed in the middle is not a target for abnormal noise detection, it is possible to prevent a decrease in the accuracy of abnormal noise detection.

The schematic diagram of an abnormal sound detection apparatus. An example of calculating the degree of abnormality for a feature vector. An example of the result of the hierarchical clustering with respect to the feature vector. An example of the relationship between average time and abnormal sound discrimination performance. An example of the relationship between the number of sounds in one octave and the noise discrimination performance. The block diagram of an abnormal noise detection apparatus. The flowchart of an abnormal sound detection process.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the applicable embodiment of the present invention is not limited to this.

[Overview]
FIG. 1 is a schematic diagram of an abnormal sound detection device 10 of the present embodiment. The abnormal sound detection device 10 is installed in the railway vehicle 20 and performs voice analysis processing on the traveling sound collected by the microphone 12 so as to be included in traveling sounds generated by various devices such as motors and abnormalities in the traveling track. Detects abnormal noise. The abnormal sound detection device 10 detects the abnormal noise included in the traveling sound by comparing the traveling sound in the vehicle collected by the microphone 12 with the traveling sound in the normal time collected in advance. For this reason, it is desirable that the abnormal sound detection device 10 be installed in a cab where, for example, passengers' voices are difficult to be collected so that the conditions for collecting both traveling sounds are close. The microphone 12 and the main unit may be separated from each other by wire or wirelessly, and the microphone 12 may be installed near the floor of the cab.

The abnormal noise detection in this embodiment will be described.
(A) Calculation of Feature Vector First, a feature vector is calculated from running sound data input from the microphone 12. Specifically, 1 / M (M ≧ 4) octave analysis is performed on the running sound data, and a predetermined average time (smoothing time) of 2.5 seconds to 5 seconds for each octave band (frequency band). ) Calculate the sound pressure after moving average processing at Ts. Then, a feature vector x having the sound pressure of each octave band as an element is calculated.

(B) Abnormal sound determination Next, by using a one-class support vector machine, the calculated feature vector is compared with the characteristic vector of the normal traveling sound to determine whether the traveling sound includes the abnormal sound. judge.

(B-1) One-class support vector machine The one-class support vector machine is a technique that applies a support vector machine that is a learning model for classifying feature vectors into two classes (groups). The support vector machine obtains a hyperplane for classifying the learning data in which the class is determined so that the distance (margin) between the two classes of data is maximized, and uses this hyperplane to determine the feature vector to be determined. Classify into either class.

  The one-class support vector machine uses only one class of normal data as learning data, obtains a hyperplane for classifying normal data and other data, and uses this hyperplane to determine a feature vector to be determined Is classified as either normal or abnormal.

この判別関数ｆ（ｘ）が正値の場合には特徴ベクトルｘは正常、負値の場合には特徴ベクトルｘは異常と判別する。 In the one-class support vector machine, the discriminant function f (x) used for discriminating the normality / abnormality of the feature vector x is determined by the following equation (1).

When the discriminant function f (x) is a positive value, the feature vector x is judged as normal, and when the discriminant function f (x) is negative, the feature vector x is judged as abnormal.

式（２）において、パラメータνは、例えば０．１に設定される。また、関数ｋ（ｘ，ｙ）はカーネル関数であり、ガウシアンカーネルを用いると、次式（３）で定められる。

In equation (1), vector xi is a support vector. The support vector is a feature vector in which the corresponding coefficient a is not “0” among the feature vectors x of normal data. The coefficient ai of the support vector xi is calculated as a solution to the minimization problem of the following equation (2).

In equation (2), the parameter ν is set to 0.1, for example. Further, the function k (x, y) is a kernel function, and is defined by the following equation (3) when a Gaussian kernel is used.

In Expression (3), the parameter σ is determined as the maximum value of the distance between feature vectors, for example. The parameter ρ is given by the following equation (4).

(B-2) Abnormal Sound Detection In this embodiment, using the discriminant function f (x) of the one-class support vector machine, the abnormality degree g for the feature vector x of the traveling sound data to be detected is expressed by the following equation (5) ) Is determined as an abnormal degree calculation function g (x).

  This abnormality degree calculation function g (x) is a value obtained by normalizing the value obtained by the discriminant function f (x) with the parameter ρ. It can be said that the evaluation value is normalized by a one-class support vector machine. Therefore, when the degree of abnormality g is a positive value, it is determined that the running sound includes an abnormal noise, and when the abnormality level g is a negative value, it is determined that no abnormal noise is included. In addition, the degree of abnormality g is a value in the range of “−1.0 to +1.0”, and the higher the positive value and the absolute value, the higher the possibility that abnormal noise is included in the traveling sound data to be detected. It can be said.

  FIG. 2 is an example of the calculation result of the degree of abnormality g. FIG. 2 shows the degree of abnormality g for the feature vectors n1 to n10 and a1 to a9 for each of the 19 types of traveling sound data. Among these, feature vectors n1 to n10 are feature vectors of normal running sound data, and in particular, feature vectors n2, n4, n6, and n10 having an abnormality degree of 0 are support vectors. Further, the feature vectors a1 to a9 are feature vectors of running sound including abnormal sounds. In particular, the feature vector a9 is a feature vector of a running sound that can be identified by human beings as clearly including an abnormal sound, and the other feature vectors a1 to a8 are different to the extent that they cannot be identified by human hearing. This is a feature vector of running sound including sound.

  As shown in FIG. 2, the abnormalities of the feature vectors n1 to n10 of normal data are all 0 or a negative value. In addition, the abnormalities of the feature vectors a1 to a9 of the traveling sound data to be detected are all positive values, indicating that abnormal sounds are included. In particular, the degree of abnormality of the feature vector a9 is prominent as compared to the other feature vectors a1 to a8.

(C) Parameter for calculating feature vector The calculated feature vector differs depending on the parameter when calculating the feature vector. For this reason, the ability to determine whether or not the running sound includes abnormal noise depends on the parameters used when calculating the feature vector. Here, the difference in the noise discrimination performance when the average time Ts and the 1 / N value of the octave analysis, which are parameters for calculating the feature vector, are different will be described.

  Allophone discrimination performance was judged by hierarchical clustering. In the dendrogram generated by this hierarchical clustering, the length of a feature vector branch represents the degree of similarity between the feature vector and another feature vector closest to the feature vector.

  FIG. 3 is an example of a dendrogram generated by hierarchical clustering. 3 (a) and 3 (b) both use the same running sound data as the 19 kinds of running sound data used in FIG. 2, and change and average only the average time Ts for the octave analysis result. This is a result of performing hierarchical clustering on. Specifically, FIG. 3A shows an average time Ts of about 0.2 seconds, and FIG. 3B shows an average time Ts of about 3.0 seconds.

  As described above, among the feature vectors n1 to n10 and a1 to a9, the feature vectors n1 to n10 are feature vectors of normal running sound data. The feature vectors a1 to a9 are feature vectors of running sound data including abnormal sounds. In particular, the feature vector a9 is a feature vector of running sound data containing obvious abnormal sounds that can be identified by human hearing.

  As shown in FIG. 3, it can be seen that even with the same traveling sound data, the detection performance of abnormal noise differs depending on the parameter (here, average time Ts) related to the calculation of the feature vector. That is, in FIG. 3A, it can be said that the branch of the feature vector a2 is the longest and the abnormal sound cannot be correctly identified. On the other hand, in FIG. 3B, the length of the branch of the feature vector a9, which is an abnormal sound, is the longest and the length protrudes from the other feature vectors, and the abnormal sound can be discriminated. I can say that.

  A value obtained by dividing the length of the branch corresponding to the feature vector of the abnormal sound by the length of the longest branch among the other feature vectors is used as an index of the abnormal sound discrimination performance by hierarchical clustering. In other words, this abnormal sound discrimination performance index is a value of 1 or more when the length of the branch of the abnormal noise feature vector is the longest, and the larger this value is, the clearer the abnormal sound is identified. Show. This index is used in FIGS.

  In this hierarchical clustering, since it is necessary to calculate the distance between all feature vectors, there is a disadvantage that the amount of calculation increases as the number of feature vectors increases. Therefore, a method using hierarchical clustering is also possible as a method for detecting abnormal noise. However, when an abnormal noise detection device is installed in a running railway vehicle to detect abnormal noise in real time, the amount of calculation is as much as possible. It is necessary to suppress. Therefore, in this embodiment, a one-class support vector machine is used. One-class support vector machines have the advantage that the amount of calculation required to evaluate feature vectors is small.

(C-1) Average time Ts
FIG. 4 is a diagram illustrating an example of the relationship between the average time Ts in the octave analysis and the abnormal sound discrimination performance. A plurality of traveling sound data including traveling sound data including obvious abnormal sounds that can be discerned by human hearing was prepared, and an index of the abnormal sound discrimination performance was calculated by the above-described method using hierarchical clustering.

  FIG. 4 shows the result of calculating an abnormal sound discrimination performance index by changing the average time Ts, which is a parameter relating to the calculation, in the range of “2.0 to 6.0 seconds” in calculating the feature vector. ing. FIG. 4 shows a case where 1/4 octave analysis (that is, the number of sounds in one octave is “4”), but 1/6 octave analysis (that is, the number of sounds in one octave). Is “6”), the waveforms are almost the same.

  According to FIG. 4, when the average time Ts is 2.0 to 2.7 seconds, the noise discrimination performance increases (improves) almost linearly as the average time Ts increases. I couldn't see it. Further, when the average time Ts was 4.0 to 5.0 seconds, the noise discrimination performance increased or decreased, but generally showed a high value. Further, when the average time Ts was more than 5.0 seconds, the abnormal sound discrimination performance was gradually lowered. As the average time Ts increases, the amount of calculation increases and processing delay occurs. For this reason, it is considered that the average time Ts is preferably about 2.5 to 5.0 seconds, and more preferably about 2.5 to 3.0 seconds, from the viewpoint of ease of data processing and followability to state changes.

(C-2) Number of sounds in one octave FIG. 5 is a diagram illustrating an example of the relationship between the number of N in the 1 / N octave analysis and the noise discrimination performance. A plurality of traveling sound data including traveling sound data including obvious abnormal sounds that can be discerned by human hearing was prepared, and an index of the abnormal sound discrimination performance was calculated by the above-described method using hierarchical clustering.

  In FIG. 5, in calculating the feature vector, the number N of sounds in one octave, which is a parameter related to the calculation, is changed to 0, 1,. Results are shown. The average time Ts was 3 seconds. According to FIG. 5, the abnormal sound discrimination performance is lower when N is “2” than “1”. In addition, in the case of “3” or higher, the noise discrimination performance is higher than in the case of “1”. In addition, the noise discrimination performance increased (improved) as N changed from “2” to “4”, but the maximum was “4”, and there was almost no change when “5 or more”. Accordingly, it can be said that N is desirably “4” or more. That is, it is desired that 1 / M (M ≧ 4) octave. Further, as the value of M increases, the amount of calculation increases, and the abnormal sound discrimination performance becomes maximum at “4”. For this reason, the number of sounds in one octave is “4”, that is, octave analysis of a quarter octave band is considered more suitable.

[Function configuration]
FIG. 6 is a configuration diagram of the abnormal sound detection device 10. According to FIG. 6, the abnormal sound detection device 10 includes an audio input unit 110, an operation input unit 120, a display unit 130, an audio output unit 140, a processing unit 200, and a storage unit 300. The

  The sound input unit 110 is a sound collection device realized by, for example, a microphone, and outputs collected sound data to the processing unit 200. The voice data input from the voice input unit 110 is stored and stored as the running sound data 330 in association with the time of sound collection.

  The operation input unit 120 is an input device realized by, for example, a keyboard, a mouse, a touch panel, various switches, and the like, and outputs an input signal corresponding to the operation input to the processing unit 200. The display unit 130 is a display device realized by, for example, a liquid crystal display (LCD) or an electroluminescent display (ELD), and performs various screen displays based on display signals from the processing unit 200. The audio output unit 140 is a sound output device realized by, for example, a speaker, and performs various audio outputs based on the audio signal from the processing unit 200.

  The processing unit 200 is realized by an arithmetic device such as a CPU, for example, and performs overall control of the abnormal sound detection device 10 based on programs, data, and the like stored in the storage unit 300. The processing unit 200 includes an octave analysis unit 210, a feature vector calculation unit 220, and an abnormal sound determination unit 230, and performs an abnormal sound detection process (see FIG. 7) according to the abnormal sound detection program 310.

  The octave analysis unit 210 performs an octave analysis on the running sound input from the voice input unit 110 and calculates the sound pressure of each frequency band (octave band). In the present embodiment, an octave analysis of a quarter octave band is performed.

  The feature vector calculation unit 220 averages the effective value of the sound pressure in each frequency band calculated by the octave analysis over a predetermined average time Ts, and the feature vector x having the average sound pressure in each frequency band as an element. Is calculated. The calculated feature vector x is stored and stored as feature vector data 340 in association with the sound collection time of the corresponding traveling sound data.

  The abnormal sound determination unit 230 compares the feature vector x calculated by the feature vector calculation unit with the feature vector xi (i = 1, 2,..., L) of the normal traveling sound data, thereby driving the vehicle. It is determined whether or not an abnormal sound is included in the sound. Specifically, the degree of abnormality g of the feature vector x is calculated according to equation (5) using a one-class support vector machine. If the calculated degree of abnormality g is a positive value, it is determined that abnormal noise is included, and if not, it is determined that abnormal noise is not included. This corresponds to evaluating whether or not the feature vector that has been subjected to the moving average processing corresponds to the feature vector related to the running sound data at the normal time.

  Here, the feature vector xi of the running sound data at the normal time is stored as the feature vector data 320 at the normal time. The calculated degree of abnormality g is accumulated and stored as abnormal sound detection result data 350 in association with the sound collection time of the corresponding traveling sound data.

  The storage unit 300 stores a system program for realizing various functions for the processing unit to integrally control the abnormal sound detection device, a program and data for realizing the present embodiment, and the processing unit. The operation data from the operation input unit, the voice data from the voice input unit, and the like are temporarily stored. In the present embodiment, the abnormal sound detection program 310, the normal feature vector data 320, the running sound data 330, the feature vector data 340, and the abnormal sound detection result data 350 are stored.

[Process flow]
FIG. 7 is a flowchart for explaining the flow of abnormal noise detection processing. According to FIG. 7, first, when the predetermined detection timing is reached (step S1: YES), the octave analysis unit 210 performs an octave analysis on the input running sound data, and the sound of each frequency band. The pressure is calculated (step S3). The detection timing in step S1 is, for example, when a predetermined time (for example, 5 seconds) has elapsed after departure from the stop station, or when a notch (powering notch and / or brake notch) becomes a predetermined notch. The timing when the driving operation satisfies a predetermined driving operation condition, such as when the vehicle is traveling on the road, can be set. In addition, a traveling position calculation device may be provided on the vehicle, and the timing when the vehicle passes a position satisfying a predetermined position condition (for example, a predetermined kilometer position) may be set as the detection timing.

  Next, the feature vector calculation unit 220 performs a moving average process on the calculated sound pressure in each frequency band for a predetermined average time Ts (step S5), and calculates a feature vector x of the running sound using the averaged sound pressure as an element. (Step S7).

  Subsequently, the abnormal sound determination unit 230 calculates the degree of abnormality g of the calculated feature vector x, and determines whether or not the traveling sound includes abnormal sound according to the sign of the calculated degree of abnormality g. That is, if the degree of abnormality g is a positive value, it is determined that the running sound includes abnormal noise, and if it is not a positive value, it is determined that no abnormal noise is included (normal) (step S9). Then, for example, the abnormal sound determination result is output by a predetermined display output to the display unit 130, a predetermined audio output to the audio output unit 140, or the like (step S11).

  Thereafter, it is determined whether or not the abnormal sound detection process is ended by satisfying an end condition such as arrival at the terminal station. If not (NO at step S13), the process returns to step S1 to perform the same process. If completed (step S13: YES), this process is terminated.

[Function and effect]
As described above, the abnormal sound detection device 10 according to the present embodiment easily and inexpensively detects abnormal noise generated due to an abnormality of various devices mounted on the railway vehicle 20 based on the running sound of the railway vehicle. be able to. In other words, a 1/4 octave analysis is performed on the running sound, and a feature vector having a sound pressure obtained by moving average processing for each frequency band (octave band) at a predetermined average time Ts as an element is generated. By comparing the generated feature vector with the feature vector of the normal traveling sound, it is determined whether or not the traveling sound includes abnormal noise. Thereby, abnormal noise detection for a plurality of devices and parts mounted on the railway vehicle becomes possible.

[Modification]
It should be noted that embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention.

(A) Abnormality g
In the above-described embodiment, when the degree of abnormality g is a positive value, it is determined that the running sound includes abnormal noise. However, a threshold value of the abnormality degree g for determining that abnormal noise is included is determined and calculated. If the degree of abnormality g is a positive value and greater than or equal to this threshold value, it may be determined that the running sound includes abnormal noise.

(B) Traveling state of railway vehicle Further, according to the traveling state of the railway vehicle, a feature vector of traveling sound at normal time may be selected to obtain the degree of abnormality g. Specifically, a feature vector of normal running sound is prepared for each of a plurality of types of running states such as power running, running and braking (regeneration). Then, when executing the abnormal noise detection process, the travel state at the time of sound collection is acquired, and the abnormality level calculation of Expression (5) is performed using the feature vector of the normal travel sound corresponding to the acquired travel state. The degree of abnormality g is calculated from the function g (x). When the traveling state is different, the operation sound of the motor is different, and thus the collected traveling sound is different. For this reason, it is possible to improve the accuracy of abnormal noise detection by selecting and switching the normal special vector used for calculating the degree of abnormality g in accordance with the traveling state.

  Further, in this case, when the running state at the time of collecting the running sound does not continue for the average time Ts for performing the moving average process, that is, when the running state of the railway vehicle changes during the collecting of the running sound. May not perform (suppress) abnormal noise detection based on the collected traveling sound.

DESCRIPTION OF SYMBOLS 10 Abnormal noise detection apparatus, 12 Microphone 110 Audio | voice input part, 120 Operation input part 130 Display part, 140 Audio | voice output part 200 Processing part 210 Octave analysis part, 220 Feature vector calculation part, 230 Abnormal sound determination part 300 Storage part 310 Abnormal sound Detection program 320 Normal feature vector data, 330 Running sound data 340 Feature vector data, 350 Abnormal sound detection result data

Claims (7)

An abnormal sound detection device that detects abnormal noise of various devices of the railway vehicle or abnormal noise of a traveled track based on traveling sound data collected by a sound collector provided at a predetermined position of the railway vehicle,
Analyzing means for analyzing the running sound data in a 1 / M octave band (M ≧ 4);
Moving average processing means for moving average processing the sound pressure data of each frequency band analyzed by the analysis means at a predetermined smoothing time of 2.5 seconds or more and 5 seconds or less;
Evaluation that evaluates whether or not the feature vector that is the data of each frequency band that has been subjected to the moving average processing corresponds to the feature vector when normal running sound data is processed by the analysis means and the moving average processing means Processing means;
An abnormal sound detection device. The analysis means performs analysis in a quarter octave band.
The abnormal sound detection device according to claim 1. The evaluation processing means performs the evaluation by performing an evaluation operation by a one-class support vector machine in which parameters are determined based on a feature vector related to normal running sound data.
The abnormal sound detection device according to claim 1 or 2. The evaluation processing means includes
Normalization means for normalizing the evaluation value by the one-class support vector machine;
Means for determining whether or not the normalized value satisfies a predetermined threshold condition for determining that the noise is abnormal;
Having
The abnormal sound detection device according to claim 3. Further comprising an acquisition means for acquiring a running state of the railway vehicle at the time of collecting the running sound data;
The evaluation processing means performs the evaluation by executing an evaluation calculation in which a parameter is set based on a feature vector related to running sound data in a normal state and in the obtained running state.
The abnormal noise detection apparatus as described in any one of Claims 1-4. The traveling sound data when the traveling state at the time of sound collection of the traveling sound data is not continued for the smoothing time or more is inhibited from being evaluated by the evaluation processing means, and the traveling when the traveling sound data is continued for the smoothing time or more. Causing the evaluation processing means to evaluate the sound data;
The abnormal sound detection device according to claim 5. Based on traveling sound data collected by a sound collecting device provided at a predetermined position of a railway vehicle, the computer can realize a function of detecting abnormal sounds of various devices of the railway vehicle or abnormal sounds of a track that has traveled. A program,
Analyzing means for analyzing the running sound data in a 1 / M octave band (M ≧ 4);
A moving average processing means for performing a moving average process on the sound pressure data of each frequency band analyzed by the analyzing means at a predetermined smoothing time of 2.5 seconds or more and 5 seconds or less;
Evaluation that evaluates whether or not the feature vector that is the data of each frequency band that has been subjected to the moving average processing corresponds to the feature vector when normal running sound data is processed by the analysis means and the moving average processing means Processing means,
A program for causing the computer to function as

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