JP6964872B2 - Ship engine speed estimation device, ship engine speed estimation method and ship engine speed estimation program - Google Patents

Description

The present invention relates to a ship engine speed estimation device for estimating the speed of a ship propulsion engine, a ship engine speed estimation method, and a ship engine speed estimation program.

Conventionally, in the field of automobiles, a method of collecting acoustic signals in a vehicle with a mobile terminal, extracting the engine speed from the analysis result of the acoustic signals, and estimating the accelerator opening degree has been disclosed (Patent Document 1). ..

On the other hand, in the field of ships, a device for monitoring the rotation speed of a propulsion engine (also referred to as a "main engine") is usually provided for a large ship. On the other hand, small ships (for example, ships of 19 tons or less or less than 24 meters) may not be provided with such a monitoring device, and the rotation speed of the propulsion engine cannot be grasped.

Japanese Unexamined Patent Publication No. 2015-175288

For ships, it is conceivable to estimate the number of revolutions of the propulsion engine by collecting and analyzing the sounds inside the ship in the same way as for automobiles. However, in the case of a ship, unlike the case of an automobile, various noises exist in addition to the operating noise of the propulsion engine (hereinafter, also referred to as "engine noise"). For example, it includes various sounds such as sounds emitted by various equipment inside the ship (rudder plate, wireless communication, etc.), operating sounds of the power generation engine for driving the generator, and sounds outside the ship (waves, wind, etc.). Is done. Therefore, it is not easy to extract the operating sound of the propulsion engine from the collected data.

Even if the operating sound of the propulsion engine can be extracted from the noise inside the ship, the spectrum (power spectrum) of the engine sound includes a plurality of peaks. Specifically, as shown in FIG. 20, the power spectrum of the engine sound has a peak of 1 times (fundamental frequency), 2 times, 3 times, and so on, and is 1.5 times. It also has peaks of half-integer times, 2.5 times, 3.5 times, and so on. As can be seen from the fact that the peak of 1.5 times is the maximum in the example of FIG. 20, the peak of the fundamental frequency is not always the maximum. The power spectrum also differs depending on the type of engine. Further, even if the engine is the same, the power spectrum differs depending on the type of ship (for example, the shape of the hull) and the state of the ship (for example, the load capacity of the load such as fishing gear). Therefore, even if the power spectrum of the engine sound can be obtained, it is not easy to immediately estimate the rotation speed of the propulsion engine.

The present invention has been made based on the above technical recognition, and an object of the present invention is a ship engine speed estimation device and a ship engine capable of estimating the speed of a propulsion engine from ship noise with high accuracy. It is to provide a rotation speed estimation method and a ship engine rotation speed estimation program.

The ship engine speed estimation device according to the present invention is
A ship engine speed estimation device that estimates the speed of a ship's propulsion engine.
A data acquisition unit that acquires sound frame data having a predetermined time width for each predetermined data acquisition time from recorded data that records inboard noise including engine noise of the propulsion engine.
A Fourier transform unit that generates a sound frame spectrum by Fourier transforming the sound frame data,
An averaging processing unit that generates an average sound frame spectrum by averaging a predetermined number of continuous sound frame spectra.
A volume filter created based on a volume profile showing the relationship between the number of revolutions of the propulsion engine and the volume of the inboard noise, and an operating frequency band of the propulsion engine based on the volume of the average sound frame spectrum. And a volume filter processing unit that acquires a passing spectrum that passes through the operating frequency band of the average sound frame spectrum.
A first peak extraction unit that extracts one or more peaks included in the passing spectrum as a first peak group, and a first peak extraction unit.
When the number of peaks included in the first peak group is one, a rotation speed calculation unit that calculates the rotation speed of the propulsion engine based on the frequency of the peak, and a rotation speed calculation unit.
It is characterized by having.

Further, in the ship engine speed estimation device,
Based on the number of cylinders, the number of cycles, and the rated rotation speed of the propulsion engine, the basic frequency at the rated rotation speed of the propulsion engine is calculated, and the upper limit of the frequency to be analyzed is set based on the basic frequency. Setting section and
Before averaging the predetermined number of the sound frame spectra, a spectrum removing unit that removes frequency components above the upper limit of the sound frame spectrum and
May be further provided.

Further, in the ship engine speed estimation device,
The data acquisition time may be shorter than the time width of the sound frame data.

Further, in the ship engine speed estimation device,
The predetermined number of the sound frame spectra may be three or more.

Further, in the ship engine speed estimation device,
A moving average processing unit that obtains a moving average spectrum of the average sound frame spectrum and generates a sound frame difference spectrum by subtracting the moving average spectrum from the average sound frame spectrum.
A second peak extraction unit that extracts a plurality of peaks as a second peak group from the sound frame difference spectrum, and a second peak extraction unit.
When the first peak group includes a plurality of peaks, the first peak group is an integral multiple of the fundamental frequency of the propulsion engine based on the first peak group and the second peak group. And a multiple frequency processing unit that extracts peaks of half-integer multiples,
When the number of peaks extracted by the multiple frequency processing unit is one, the rotation speed calculation unit may calculate the rotation speed of the propulsion engine based on the frequency of the peak.

Further, in the ship engine speed estimation device,
The moving average processing unit may delete a portion of the sound frame difference spectrum below a predetermined bias line.

Further, in the ship engine speed estimation device,
The multiple frequency processing unit
The product of the first matrix whose element is the reciprocal of the frequency of each peak included in the first peak group and the second matrix whose element is the frequency of each peak included in the second peak group. Calculate and
A third matrix is created by determining whether or not each element of the matrix obtained by the calculation is within the bandwidth of the harmonic band path filter which is an integral multiple and a half integer multiple of the fundamental frequency, and the third matrix is created. Peaks of integral multiples and half integral multiples of the basic frequency of the propulsion engine may be extracted based on the matrix of.

Further, in the ship engine speed estimation device,
When a plurality of peaks are extracted by the multiple frequency processing unit, a coefficient of variation indicating fluctuation of the peak power of the predetermined number of sound frame spectra is calculated for each frequency of each peak, and the coefficient of variation is calculated with respect to the frequency of each peak. Further provided with a coefficient of variation filter processing unit that determines the fundamental frequency of the propulsion engine based on a plurality of calculated coefficient of variation.
The rotation speed calculation unit may calculate the rotation speed of the propulsion engine based on the peak frequency determined by the coefficient of variation filter processing unit.

Further, in the ship engine speed estimation device,
Before calculating the coefficient of variation, the coefficient of variation filtering unit obtains an average value of the peak powers of the predetermined number of sound frame spectra, and based on the deviation width from the average value, the predetermined number of peak powers. A part of it may be removed from the calculation target of the coefficient of variation.

The ship engine speed estimation method according to the present invention is
A method for estimating the number of revolutions of a ship engine, which estimates the number of revolutions of a ship's propulsion engine.
A step of acquiring sound frame data having a predetermined time width at a predetermined data acquisition time from the recorded data obtained by recording the inboard noise including the engine sound of the propulsion engine.
A step of generating a sound frame spectrum by Fourier transforming the sound frame data,
A step of generating an average sound frame spectrum by averaging a predetermined number of consecutive sound frame spectra.
A volume filter created based on a volume profile showing the relationship between the number of revolutions of the propulsion engine and the volume of the inboard noise, and an operating frequency band of the propulsion engine based on the volume of the average sound frame spectrum. And the step of acquiring the passing spectrum passing through the operating frequency band in the average sound frame spectrum.
A step of extracting one or more peaks included in the passing spectrum as a first peak group, and
When the number of peaks included in the first peak group is one, the step of calculating the rotation speed of the propulsion engine based on the frequency of the peak, and
It is characterized by having.

The ship engine speed estimation program according to the present invention is
A ship engine speed estimation program for estimating the speed of a ship's propulsion engine.
A step of acquiring sound frame data having a predetermined time width at a predetermined data acquisition time from the recorded data obtained by recording the inboard noise including the engine sound of the propulsion engine.
A step of generating a sound frame spectrum by Fourier transforming the sound frame data,
A step of generating an average sound frame spectrum by averaging a predetermined number of consecutive sound frame spectra.
A volume filter created based on a volume profile showing the relationship between the number of revolutions of the propulsion engine and the volume of the inboard noise, and an operating frequency band of the propulsion engine based on the volume of the average sound frame spectrum. And the step of acquiring the passing spectrum passing through the operating frequency band in the average sound frame spectrum.
A step of extracting one or more peaks included in the passing spectrum as a first peak group, and
When the number of peaks included in the first peak group is one, the step of calculating the rotation speed of the propulsion engine based on the frequency of the peak, and
Let the computer run.

According to the present invention, the rotation speed of the propulsion engine can be estimated with high accuracy from the noise inside the ship.

It is a figure which shows the schematic structure of the ship 100 which concerns on one example. It is a figure which shows the schematic structure of the ship engine rotation speed estimation device 1 which concerns on embodiment. It is a figure which shows the schematic structure of the control part 50 which concerns on 1st Embodiment. This is an example of a graph showing a volume profile of inboard noise measured in advance. This is an example of a graph for explaining how to set a limiter line in the volume profile. This is an example of a graph showing the created volume filter. It is a graph for demonstrating the method of creating a volume filter which concerns on a modification. It is a figure for demonstrating the method of acquiring the sound frame data from the recorded data of the noise in a ship. This is an example of a graph showing an average sound frame spectrum. It is a figure for demonstrating the method to acquire the passing spectrum by passing the average sound frame spectrum through a volume filter. It is a flowchart for demonstrating the process flow of advance preparation. It is a flowchart for demonstrating the ship engine rotation speed estimation method which concerns on 1st Embodiment. This is an example of a graph showing a passage spectrum having a plurality of peaks. It is a figure which shows the schematic structure of the control part 50A which concerns on 2nd Embodiment. This is an example of a graph showing an average sound frame spectrum and a spectrum obtained by moving average processing the average sound frame spectrum. This is an example of a graph showing a sound frame difference spectrum and a threshold value (bias line). This is an example of a graph showing a spectrum cut by a bias line. (A) is a diagram showing each element of the matrix X, and (b) is a diagram showing an example of each element of the matrix Y. About five sound frame spectrum, the reference value (frequency _{f p)} power value of a frequency that matches the ^{_{P fp j (j = 1,2,}} ···, 5) are diagrams showing a. It is a figure for demonstrating the process of removing a part of the extracted power value before calculating the coefficient of variation. It is a flowchart for demonstrating the ship engine rotation speed estimation method which concerns on 2nd Embodiment. This is an example of the power spectrum of the engine sound of a propulsion engine.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

(First Embodiment)
First, with reference to FIG. 1, a schematic configuration of the ship 100 according to an example will be described. As shown in FIG. 1, the ship 100 is provided with a propulsion engine 110 that rotates the propeller 140 and a power generation engine 120 that rotates the generator 130. The power generation engine 120 and the generator 130 are not indispensable configurations. For example, when the electric equipment (cooling / heating, lighting, winch, etc.) in the ship is driven by the battery, the power generation engine 120 and the generator 130 do not have to be provided in the ship 100.

As shown in FIG. 1, the ship 100 is provided with a ship engine speed estimation device 1. The ship engine rotation speed estimation device 1 is configured to estimate the rotation speed of the propulsion engine 110 of the ship 100, as will be described in detail later. The ship engine rotation speed estimation device 1 may be an information processing device (personal computer or the like) installed in the ship 100, or an information processing terminal (smartphone, tablet terminal or the like) carried by a sailor. ..

In the present embodiment, the ship 100 is a small ship having a total length of less than 24 meters or a total ton number of 19 tons or less. The ship engine rotation speed estimation device 1 is not only applied to small ships, but may be used to estimate the rotation speed of the propulsion engine of a medium-sized ship or a large ship.

<Ship engine speed estimation device>
Next, a schematic configuration of the ship engine speed estimation device 1 will be described with reference to FIG.

As shown in FIG. 2, the ship engine speed estimation device 1 includes a sound input unit 10, an information input unit 20, an information output unit 30, a storage unit 40, and a control unit 50. The ship engine rotation speed estimation device 1 may have a communication unit (not shown) for transmitting / receiving information to / from another information processing device via a communication network such as the Internet. Further, the ship engine rotation speed estimation device 1 may have a position detecting means such as GPS (Global Positioning System) and an acceleration sensor.

Hereinafter, each configuration of the ship engine speed estimation device 1 will be described.

The sound input unit 10 is a device for inputting the surrounding sound of the ship engine speed estimation device 1. The sound input unit 10 is composed of, for example, a microphone mounted on an information processing terminal such as a smartphone.

The sound input unit 10 inputs the noise inside the ship as the sound around the ship engine speed estimation device 1. The “inboard noise” is the noise in the ship 100 including the engine sound of the propulsion engine 110. Inboard noise includes, for example, engine noise of the propulsion engine 110, noise emitted by various equipment inside the vessel (rudder plate, wireless equipment, nautical instruments, etc.), noise outside the vessel (wind, wave noise, etc.). The operating noise of the power generation engine 120 and the like are included.

The onboard noise input by the sound input unit 10 is converted into a digital signal and then stored in the storage unit 40 as recorded data. The recorded data of the noise inside the ship may be stored in an external storage device (not shown) communication-connected to the ship engine rotation speed estimation device 1.

In order to analyze the engine sound in detail, it is preferable to make the frequency resolution when recording the inboard noise as small as possible. On the other hand, the smaller the frequency resolution, the longer the sampling time, and the more the real-time property is impaired. In this embodiment, 44.1 kHz used for audio recording is used as the sampling frequency Fs. In this case, assuming that the number of sampling points Ns is 2 bytes, the frequency resolution ΔF is 0.6729 [Hz] (= 44,100 / 65,536). Therefore, the inboard noise sampling time (1 / ΔF) is about 1.5 seconds. In the present embodiment, as will be described later, the real-time property is ensured by making the recording data acquisition interval (data acquisition time) shorter than the sound frame data time width (about 1.5 seconds).

The information input unit 20 is an interface for the user to input information to the ship engine rotation speed estimation device 1, and is, for example, a touch panel, a keyboard, a mouse, a button, or the like. The sound input unit 10 may function as an information input unit. The user inputs values necessary for estimating the rotation speed of the propulsion engine 110, such as the rated rotation speed of the propulsion engine 110, the number of cylinders, and the number of cycles, via the information input unit 20.

The information output unit 30 is an interface that outputs various information (for example, an estimated number of rotations) to the user, and is, for example, a display (liquid crystal display, organic EL display, etc.) that displays an image.

The information output unit 30 may be a speaker that outputs information by voice. When the information input unit 20 is a touch panel, the information input unit 20 may also serve as the information output unit 30.

Further, the information output unit 30 may output a video signal or a voice signal to a video display means or a voice output means connected to the outside of the ship engine rotation speed estimation device 1, or may be connected to the outside. The data may be output to a printing device (printer), or the data may be output and stored in a storage device inside or outside the ship engine rotation speed estimation device 1.

The storage unit 40 is a storage device composed of a hard disk, a semiconductor memory, or the like. The storage unit 40 stores data necessary for information processing by the control unit 50, and also stores information generated by the control unit 50.

The control unit 50 controls the operation of the ship engine rotation speed estimation device 1, and is composed of a processor such as a CPU (central processing unit) as hardware.

Next, the control unit 50 will be described in detail with reference to FIG.

The control unit 50 includes a frequency upper limit setting unit 51, a volume filter creation unit 52, a data acquisition unit 53, a Fourier transform unit 54, a spectrum removal unit 55, an averaging processing unit 56, and a volume filter processing unit 57. It has a peak extraction unit (first peak extraction unit) 58 and a rotation number calculation unit 59. Each unit of the control unit 50 is realized by the processor in the ship engine rotation speed estimation device 1 executing a predetermined program (for example, a smartphone application). At least one of these functional units may be realized by the hardware in the ship engine speed estimation device 1.

Hereinafter, each unit of the control unit 50 will be described in detail.

The frequency upper limit setting unit 51 acquires the values of the rated rotation speed, the number of cylinders, and the number of cycles of the propulsion engine 110 via the information input unit 20. The frequency upper limit setting unit 51 may read a parameter value (a value of at least one of the rated rotation speed, the number of cylinders, and the number of cycles) stored in the storage unit 40 in advance from the storage unit 40.

The frequency upper limit setting unit 51 calculates the fundamental frequency at the rated rotation speed of the propulsion engine 110 based on the number of cylinders, the number of cycles, and the rated rotation speed of the propulsion engine 110. Specifically, the fundamental frequency of the engine sound at the rated rotation speed is calculated using the equation (1).

Here, _Rated : the fundamental frequency of the engine sound at the rated rotation speed, _Rated : the rated rotation speed [rpm], C: the number of cylinders of the propulsion engine 110, S: the number of cycles (stroke) of the propulsion engine 110. be.

The frequency upper limit setting unit 51 sets the upper limit of the analysis target frequency (also referred to as “cutoff frequency”) based on the calculated fundamental frequency at the time of rated rotation. _{When the analysis target is up to a value of ρ k} times the fundamental frequency at the rated rotation, the frequency upper limit setting unit 51 calculates and sets the cutoff frequency using the equations (2) and (3). The set cutoff frequency is used by the spectrum removal unit 55 (details will be described later).

Here, _Flim : cutoff frequency, α: margin.

For example, when k = 3, ρ ₃ = 2, the analysis target is up to the frequency obtained by adding the margin α to twice the fundamental frequency at the rated rotation speed. The margin α may be a predetermined value or a value set by the user via the information input unit 20.

The volume filter creation unit 52 creates a volume filter (Sound Volume Filter: SVF) based on the volume profile. The volume profile is unique to the propulsion engine and the ship and shows the relationship between the number of revolutions of the propulsion engine 110 and the volume of inboard noise. Here, the "volume" is a value (integrated value) obtained by integrating the power (frequency component) below the cutoff frequency in the frequency direction with respect to the power spectrum of the noise inside the ship. When the cutoff frequency is not set, the volume is a value obtained by integrating the power spectrum values for all frequencies.

Here, a method of acquiring a volume profile will be described. First, the noise inside the ship is recorded for a plurality of rotation speeds from the idling operation state of the propulsion engine 110 to the rated speed operation state. At this time, the noise inside the ship is recorded multiple times for each rotation speed. Then, each recorded data is Fourier transformed to generate a power spectrum. Then, the volume is calculated for each power spectrum. The vertical bars in the graph of FIG. 4A indicate the variation in volume. In FIG. 4A, the horizontal axis of the graph indicates the rotation speed of the propulsion engine 110, and the rotation speed of “100%” indicates the rated rotation speed (FIGS. 4B and 5 (a) described later). , (B).)

Next, an approximate curve is obtained based on the volume data of each rotation speed. This approximation curve shows the volume profile. The solid line curve in FIG. 4A shows an example of the volume profile. Many ships do not have a variable speed mechanism like a car transmission (ie, only 1st speed), so it is possible to obtain such a volume profile.

By the way, the volume increases as the rotation speed of the propulsion engine 110 increases. With the propulsion engine 110 alone, the relationship between the volume and the number of revolutions can be expressed by a relatively simple mathematical formula. However, when the propulsion engine is mounted on the ship, the volume is affected by the fluid resistance of the ship 100 and the like, so that the volume changes in a complicated manner with respect to the rotation speed. For example, the approximate curve of the volume profile shown in FIG. 4A has a bump indicated by reference numeral H, and this bump appears due to the large fluid resistance of the hull at the rotation speed (ship speed). In the case of a small ship, if the ship speed (engine speed) is increased, it will be in a gliding state after several humps (increase / decrease in hull resistance).

The volume filter creation unit 52 creates a volume filter as follows based on the acquired volume profile.

First, the volume filter creating unit 52 obtains the _{deviation width ΔV rated as shown in FIG. 4A.} This dissociation width ΔV _rated is the dissociation width of the volume value that deviates most from the average volume value at a predetermined rotation speed. In the example of FIG. 4A, the predetermined rotation speed is the rated rotation speed. The divergence width at the rated rotation speed is often larger than the divergence width at other rotation speeds. Therefore, by using the deviation width at the rated rotation speed, the estimation accuracy of the rotation speed can be improved. The volume filter creating unit 52 may obtain the deviation width at a rotation speed other than the rated rotation speed.

Next, as shown in FIG. 4B, the volume filter creation unit 52 sets limiter lines UL and LL having a width of _{± ΔV rated in the volume profile at the top and bottom.} In FIG. 4B, the limiter line UL is the upper limiter line, and the limiter line LL is the lower limiter line.

After that, as shown in FIG. 4C, the volume filter creating unit 52 creates a volume filter by converting the horizontal axis (X axis) of the graph showing the limiter lines UL and LL into frequencies. The volume filter created in this way is stored in the storage unit 40.

The method of creating the volume filter is not limited to the above, and a simpler method can be adopted. A method of creating a volume filter according to a modified example will be described with reference to FIG. In this modification, an approximate outline line of the volume profile is created from the information of two points, the average volume Va _{- idle} at the idling speed Nidle and the average volume Va _-rated at the rated speed N _{rated operation.} The line indicating the volume profile may be a curved line or a straight line.

Specifically, first, as shown in FIG. 5A, the volume filter creating unit 52 has a point A indicating _{an average volume Va-idle when the idling speed is Nidle} , and an average when the _{rated speed is rated.} A curve C (volume profile) passing through two points with a point B indicating the volume Va _{-rated is obtained.} The curve C is, for example, an exponential curve or a quadratic curve.

Next, as shown in FIG. 5B, the volume filter creating unit 52 obtains the _{deviation width ΔV rated.} This dissociation width ΔV _rated is the dissociation width of the volume value that deviates most from the average volume value at a predetermined rotation speed. Here, a predetermined rotation speed is set as the rated rotation speed. After that, as shown in FIG. 5B, the volume filter creating unit 52 sets the limiter lines UL and LL having the width of _{± ΔV rated in the volume profile at the top and bottom.} Then, as shown in FIG. 5C, the volume filter creating unit 52 creates a volume filter by converting the horizontal axis (X axis) of the graphs of the limiter lines UL and LL into frequencies.

According to this modification, since the volume filter is created only from the information of two points, that is, the idling operation and the rated operation, the estimation accuracy of the rotation speed is lowered, but the volume filter can be easily obtained.

The data acquisition unit 53 acquires sound frame data having a predetermined time width from the recorded data obtained by recording the noise inside the ship at each predetermined data acquisition time. The data acquisition unit 53 stores the sound frame data cut out from the recorded data in the storage unit 40.

The data acquisition time is preferably shorter than the time width of the sound frame data. In other words, the data acquisition unit 53 may acquire sound frame data so as to overlap each other, as shown in FIG. As a result, real-time performance can be ensured while ensuring the time width (that is, frequency resolution) of the sound frame data.

In the present embodiment, as shown in FIG. 6, the data acquisition unit 53 obtains sound frame data SF1 to SF7 having a length of about 1.5 seconds from the recorded data SRD every 0.7 to 0.8 seconds. get. In FIG. 6, the most recently acquired sound frame data is SF7, and the data acquired immediately before that is SF6.

The Fourier transform unit 54 generates a sound frame spectrum by Fourier transforming the sound frame data. More specifically, the Fourier transform unit 54 generates the sound frame spectrum of the sound frame data by the fast Fourier transform each time the sound frame data is acquired by the data acquisition unit 53.

The Fourier transform unit 54 may store the generated sound frame spectrum data in the storage unit 40. The stored sound frame spectrum is used, for example, in the coefficient of variation filtering process described in the second embodiment.

The spectrum removal unit 55 removes frequency components equal to or higher than the _{cutoff frequency (Flim} ) of the sound frame spectrum acquired by the data acquisition unit 53 before the averaging processing unit 56, which will be described later, averages the plurality of sound frame spectra. Remove. As a result, the amount of calculation associated with subsequent data processing can be reduced. Further, since the frequency component unrelated to the engine sound is removed, the accuracy of estimating the rotation speed of the propulsion engine 110 can be improved. However, the spectrum removal unit 55 is not an essential configuration.

The spectrum removal unit 55 may store the sound frame spectrum data in which the frequency component equal to or higher than the cutoff frequency is removed in the storage unit 40. The stored sound frame spectrum is used, for example, in the coefficient of variation filtering process described in the second embodiment. Further, the spectrum removing unit 55 may remove the operating frequency of the power generation engine 120. Since the power generation engine 120 rotates at a constant rotation speed, the operating frequency is also constant and is known.

The averaging processing unit 56 generates an average sound frame spectrum by averaging a predetermined number of consecutive sound frame spectra. In the present embodiment, the averaging processing unit 56 performs averaging processing using the five sound frame spectra from the latest. FIG. 7 shows an example of the average sound frame spectrum when the arithmetic mean is taken. As shown in FIG. 7, the average sound frame spectrum includes a plurality of peaks including the peak of the fundamental frequency. In this embodiment, the average sound frame spectrum does not have a frequency component equal to or higher than the cutoff frequency.

From the viewpoint of improving the estimation accuracy of the rotation speed of the propulsion engine 110, it is preferable that the number of sound frame spectra to be averaged (predetermined number) is large, but it may be at least two. From the viewpoint of performing the coefficient of variation filtering process described later, the predetermined number is preferably 3 or more. In the present embodiment, the average sound frame spectrum is generated by averaging the five sound frame spectra. Therefore, as can be seen from FIG. 6, the average sound frame spectrum is generated using the recorded data from about 4.5 seconds ago to the present.

When the spectrum removal unit 55 is not provided, the averaging processing unit 56 averages the sound frame spectrum generated by the Fourier transform unit 54 as it is. Further, the averaging processing unit 56 may generate an average sound frame spectrum not only by arithmetic averaging but also by other averaging processing such as geometric mean.

The volume filter processing unit 57 estimates the operating frequency band of the propulsion engine 110 based on the volume filter created by the volume filter creation unit 52 and the volume of the average sound frame spectrum. In FIG. 8, the band described as “passing band” indicates the operating frequency band, and the measured volume line SL indicates the volume of the average sound frame spectrum generated by the averaging processing unit 56 (that is, the integrated value of the power spectrum). Shown. As shown in FIG. 8, the lower limit frequency of the passing band is the frequency of the intersection of the measured volume line SL and the upper limiter line UL, and the upper limit frequency of the passing band is the frequency of the measured volume line SL and the lower limiter line LL. The frequency of the intersection.

The volume of the average sound frame spectrum is calculated by the volume filter processing unit 57 based on the average sound frame spectrum generated by the averaging processing unit 56. Not limited to this, other functional units of the control unit 50, such as the averaging processing unit 56, may calculate the volume of the average sound frame spectrum.

After estimating the operating frequency band, the volume filter processing unit 57 acquires a passing spectrum that passes through the estimated operating frequency band in the average sound frame spectrum. This passing spectrum has one or more peaks and includes a fundamental frequency peak of the propulsion engine 110.

The peak extraction unit 58 extracts one or a plurality of peaks included in the passing spectrum as a first peak group. The passing spectrum is a set of numerical values (power levels) arranged at equal intervals in the frequency direction in the operating frequency band. The peak extraction unit 58 extracts the frequency of the peak (local maximum value) from this set. That is, the data of the first peak group is a set of frequency values of each peak.

When the number of peaks included in the first peak group extracted by the peak extraction unit 58 is one, the rotation speed calculation unit 59 calculates the rotation speed of the propulsion engine 110 based on the frequency of the peak. Specifically, the number of revolutions of the propulsion engine 110 is calculated using the equation (4).

Here, N: the rotation speed [rpm] of the propulsion engine 110, C: the number of cylinders, S: the number of cycles (stroke), F: the frequency of the extracted peak.

<Ship engine speed estimation method>
The processing operation of the ship engine speed estimation device 1 according to the first embodiment will be described with reference to the flowcharts of FIGS. 9 and 10. FIG. 9 shows a processing flow related to advance preparation, and FIG. 10 shows a processing flow related to the rotation speed estimation of the propulsion engine 110.

First, the processing flow related to the advance preparation will be described with reference to FIG.

As described above, the frequency upper limit setting unit 51 calculates the fundamental frequency at the rated rotation speed of the propulsion engine 110, _{and sets the cutoff frequency (Flim} ) based on the calculated fundamental frequency (step S1). ..

Next, the volume filter creation unit 52 creates a volume filter based on the volume profile as described above (step S2).

The order of steps S1 and S2 may be changed.

Next, the processing flow related to the rotation speed estimation of the propulsion engine 110 will be described with reference to FIG.

First, the data acquisition unit 53 acquires sound frame data having a predetermined time width for each predetermined data acquisition time from the recorded data obtained by recording the noise inside the ship (step S11).

Next, the Fourier transform unit 54 generates a sound frame spectrum by Fourier transforming the sound frame data acquired in step S11 (step S12).

Next, the spectrum removing unit 55 removes _{frequency components equal to} or higher than the cutoff frequency (Flim) of the sound frame spectrum acquired in step S12 (step S13).

Next, the averaging processing unit 56 generates an average sound frame spectrum by averaging a predetermined number of continuous sound frame spectra (step S14).

Next, the volume filter processing unit 57 estimates the operating frequency band of the propulsion engine 110 based on the volume filter created in step S2 and the volume of the average sound frame spectrum generated in step S14, and averages them. Of the sound frame spectrum, a passing spectrum that passes through the estimated operating frequency band is acquired (step S15).

Next, the peak extraction unit 58 extracts one or a plurality of peaks included in the passing spectrum acquired in step S15 as a first peak group (step S16).

Next, the control unit 50 determines whether or not the number of peaks included in the first peak group extracted in step S16 is one (step S17). When the number of peaks included in the first peak group is one (S17: Yes), the rotation speed calculation unit 59 determines the propulsion engine 110 based on the frequency of the peak (specified peak). The number of rotations of is calculated (step S18). Since the frequency of the specified peak is the fundamental frequency of the engine sound, the rotation speed of the propulsion engine 110 can be calculated.

On the other hand, when the number of peaks included in the first peak group is a plurality (S17: No), the narrowing process is performed (step S20). This processing content will be described in the second embodiment.

As described above, in the first embodiment, the volume filter processing unit 57 estimates the operating frequency band of the propulsion engine 110 based on the volume filter created in advance and the volume of the average sound frame spectrum. , The volume filter processing unit 57 acquires a passing spectrum that passes through the estimated operating frequency band in the average sound frame spectrum, and the rotation speed calculation unit 59 obtains the propulsion engine 110 based on the peak frequency of the passing spectrum. Calculate the number of rotations of. As described above, according to the first embodiment, the rotation speed of the propulsion engine 110 can be estimated with high accuracy from the noise inside the ship by using the volume filter peculiar to the ship that has been pre-learned.

(Second Embodiment)
Next, a second embodiment according to the present invention will be described. In the present embodiment, as shown in FIG. 11, when the first peak group extracted from the passing spectrum contains a plurality of peaks, the peaks are narrowed down and the peak of the fundamental frequency is specified. Hereinafter, the second embodiment will be described with a focus on the differences from the first embodiment. The components of the ship engine speed estimation device 1 other than the control unit 50 are the same as those in the first embodiment, and thus detailed description thereof will be omitted.

The control unit 50A according to the second embodiment will be described with reference to FIG.

In addition to each unit (frequency upper limit setting unit 51 to rotation speed calculation unit 59) of the control unit 50, the control unit 50A includes a moving average processing unit 61, a peak extraction unit (second peak extraction unit) 62, and a multiple frequency. It has a processing unit 63 and a coefficient of variation filter processing unit 64. Note that, in FIG. 12, the configuration common to the control unit 50 is not shown. Each unit of the control unit 50A is realized by the processor in the ship engine rotation speed estimation device 1 executing a predetermined program (for example, a smartphone application). At least one of these functional units may be realized by the hardware in the ship engine speed estimation device 1.

Hereinafter, each unit newly added by the control unit 50A will be described in detail.

The moving average processing unit 61 obtains the moving average spectrum of the average sound frame spectrum generated by the averaging processing unit 56. Then, the moving average processing unit 61 generates a sound frame difference spectrum by subtracting the obtained moving average spectrum from the average sound frame spectrum. In FIG. 13, the average sound frame spectrum (arithmetic mean) is shown by a broken line, and the moving average spectrum is shown by a solid line. FIG. 14 shows the sound frame difference spectrum with a solid line.

Further, the moving average processing unit 61 removes a portion of the sound frame difference spectrum below the predetermined bias line. In FIG. 14, the bias line is shown as an alternate long and short dash line. In the present embodiment, the bias line is set based on the volume of the propulsion engine 110 during idling operation. By cutting off the sound frame difference spectrum with the bias line in this way, as shown in FIG. 15, a power spectrum having a plurality of relatively high peaks can be obtained. It should be noted that partial removal of the sound frame difference spectrum by the bias line is not essential. Further, the bias line may be set by another method.

The peak extraction unit 62 extracts a plurality of peaks as a second peak group from the sound frame difference spectrum generated by the moving average processing unit 61. The sound frame difference spectrum is a set of numerical values (power levels) arranged at equal intervals in the frequency direction. The peak extraction unit 62 extracts the frequency of the peak (local maximum value) from this set.

The second peak group extracted by the peak extraction unit 62 is an integral multiple and a half-integer multiple (that is, 1.0 times, 1.5 times, 2.0 times, etc.) of the fundamental frequency of the propulsion engine 110. Includes frequency peaks.

When the first peak group extracted by the peak extraction unit 58 described in the first embodiment includes a plurality of peaks, the multiple frequency processing unit 63 is based on the first peak group and the second peak group. Then, from the first peak group, peaks that are integral multiples and half-integer multiples of the fundamental frequency of the propulsion engine 110 are extracted.

That is, the multiple frequency processing unit 63 includes a plurality of peaks (fundamental frequency candidates) included in the first peak group and a plurality of peaks (fundamental frequency and its integral multiples and half-integer multiples) included in the second peak group. The plurality of peaks included in the first peak group are narrowed down to a peak group having frequencies that are integral multiples and half-integer multiples of the fundamental frequency.

Here, the multiple frequency processing by the multiple frequency processing unit 63 will be described in detail.

First, a matrix F is created from the data of the first peak group (set of frequency values of each peak). This matrix F is a 1-by-n matrix and is represented by the equation (5).

Here, f ₁ , f ₂ , ..., F _n are the frequency values of the peaks included in the first peak group, and n is the number of peaks included in the first peak group.

For example, the matrix F is F = (72.7, 76.0, 78.7, 81.4, 82.8, 86.8, 88.8).

Next, a matrix A having elements reciprocal of the elements of the matrix F is created. This matrix A is an n-by-1 matrix and is represented by the equation (6).

Next, the matrix B is created from the data of the second peak group (set of frequency values of each peak). This matrix B is a 1-by-m matrix and is represented by the equation (7).

Here, b ₁ , b ₂ , ..., B _m are the frequency values of the peaks included in the second peak group, and m is the number of peaks included in the second peak group.

For example, the matrix B is B = (57.9, 61.2, 72.7, 86.8, 88.8, 101.6, 103.0, 115.7, 129.9, 131.9, 135.9, 144.7, 159.5, 173.6, 175.6, 188.4).

Next, the product of the matrix A and the matrix B is calculated to obtain the matrix X. As shown in the equation (8), this matrix X is a matrix of n rows and m columns.

Next, a ρ _k overtone filter (overtone bandpass filter) is prepared for the matrix X. _{The bandwidth (passing band) of the ρ k} harmonic overtone filter when the margin of error is ± e% is expressed by the equation (9).

As the ρ _k overtone filter, k (= 2ρ _k -1) bandpass filters are prepared. For example, when the analysis target is up to twice the fundamental frequency at the rated rotation speed (that is, when ρ ₃ = 2), three overtone bandpass filters (1.0 times, 1.5 times, Prepare a 2.0x filter). The middle side of the equation (9) shows the (n, m) component of the matrix X, but this is just an example. As will be described later, each component of the matrix X is contained in the middle side, and the ρ _k harmonics. Whether or not to pass the filter is determined.

From the formula (9), the bandwidth of the 1.0-fold filter is 0.95 ≦ b _m / f _n ≦ 1.05. Similarly, the bandwidth of the 1.5x filter is 1.425 ≤ b _m / f _n ≤ 1.575, and the bandwidth of the 2.0x filter is 1.90 ≤ b _m / f _n. ≦ 2.10.

Next, the matrix X is passed through each of the prepared harmonic bandpass filters. Specifically, it is determined whether or not the value of each element of the matrix X falls within the bandwidth of each harmonic bandpass filter. Then, the matrix Y is created by leaving the numerical values of the elements that have passed through any of the overtone bandpass filters as they are, while setting the elements that do not pass through the bandwidth of any of the overtone bandpass filters to 0. FIG. 16A shows each element of the matrix X, and FIG. 16B shows an example of each element of the matrix Y. In FIG. 16B, the element that does not pass through the bandwidth of any of the overtone bandpass filters is 0.

Next, the matrix Y is decomposed into _{n matrices Y 1} , Y ₂ , ..., Y n for each row. Each decomposed matrix is a 1-by-m matrix. In the example of FIG. 16B, the matrix Y ₂ = (b ₁ / f ₂ , 0, 0, ..., 0) Next, the matrix Y _p (p = 1, 2, ... n) In, each element from the first column to the mth column is totaled, and when the total value falls below a predetermined threshold value t, the matrix Y _p is discarded (that is, it is excluded from the processing to be calculated).

The threshold value t is given by, for example, the following equations (10) and (11). By using these formulas, it is possible to reduce the weight of the calculation process and improve the accuracy.

For example, in the case of ρ ₃ = 2, e = 5, t = 2.375.

On the other hand, when the total value of each element from the first column to the mth column becomes the threshold value t or more, as shown in the equation (12), _{the element f p} (scalar) of the matrix F is relative to the matrix _{Y p.} Value). In the example of equation (12), two elements b ₁ and b _m are extracted as candidates for the fundamental frequency.

When the _{above calculation process is performed on the matrix Y 1} to the matrix Y _n and the non-zero elements are narrowed down to only one, the value is specified as the fundamental frequency of the propulsion engine 110.

By the above-mentioned double frequency processing, peaks having an integral multiple and a half-integer multiple of the fundamental frequency are extracted from the plurality of peaks included in the first peak group. For example, when the frequency up to twice the fundamental frequency at the rated rotation speed is analyzed (that is, when k = 3, ρ ₃ = 2), among the plurality of peaks included in the first peak group, among the plurality of peaks, Those corresponding to peaks at 1.0 times, 1.5 times, or 2.0 times the fundamental frequency are extracted.

^{As described above, the multiple frequency processing unit 63 includes the first matrix AT} having the reciprocal of the frequency of each peak included in the first peak group as an element, and the frequency of each peak included in the second peak group. the product of the second matrix B whose elements are calculated, each element b _{m /} f _n obtained matrix X in this calculation, a predetermined numerical range set for each overtone band pass filter (pass band ), A matrix Y _p (p = 1, 2, ..., N) of 1 row and m columns is created. Then, the scalar value f _p is multiplied by the _{matrix Y p at} which the sum of the elements is equal to or greater than the threshold value t. As a result, peaks that are integral multiples and half-integer multiples of the fundamental frequency of the propulsion engine 110 are extracted. When only one peak is extracted by the double frequency processing, that peak is specified as the fundamental frequency of the propulsion engine 110.

That is, when the number of peaks included in the first peak group is narrowed down to one by the above-mentioned double frequency processing, the rotation speed calculation unit 59 uses the equation (4) as described in the first embodiment. Then, the rotation speed of the propulsion engine 110 is calculated based on the frequency of the peak.

Next, the coefficient of variation filter processing unit 64 will be described.

The coefficient of variation filter processing unit 64 performs the coefficient of variation filter processing to specify the fundamental frequency when the frequency cannot be narrowed down to one peak by the multiple frequency processing. In the coefficient of variation filtering process, a predetermined number of sound frame spectra stored in the storage unit 40 are referred to, and those having a large peak power (level) fluctuation are excluded from the candidates for the fundamental frequency.

More specifically, when a plurality of peaks are extracted by the coefficient of variation processing unit 63, the coefficient of variation filter processing unit 64 has a predetermined number (five in this embodiment) of sound frame spectra for each frequency of each peak. The coefficient of variation (CV _fp described later) indicating the fluctuation of power is calculated. Then, the fundamental frequency of the propulsion engine 110 is determined based on a plurality of coefficient of variation calculated for the frequency of each peak.

The coefficient of variation filtering will be described in detail below.

Variation coefficient filter process unit 64, a double frequency processing unit 63 non-zero elements remaining in the matrix Y _p created by (frequency of the fundamental frequency candidates), the reference value of the peak frequencies contained in the sound frame spectrum. Then, the power of the frequency matching the reference value is extracted from each of the predetermined number of sound frame spectra. 17, the five sound frame spectrum shows the reference value (frequency _{f p)} of the frequency that matches the power value ^{_{P fp j (j = 1,2,3,4,5)}} . The sound frame spectrum used here is stored in the storage unit 40 by, for example, the Fourier transform unit 54 or the spectrum removal unit 55.

The coefficient of variation filter processing unit 64 calculates the _{coefficient of variation CV fp} using the above-mentioned reference value and the power value extracted from the sound frame spectrum. The coefficient of variation _{CV fp} represents the variation of power in the frequency _{f p.}

First, variation coefficient filter process unit 64, using equation (13), calculates the average value of the power of the frequency f _p.

Here, J: sound frame a predetermined number of _{spectra, P fp} ^{j: j-th} (j = 1,2, ···, J ) is the power at the frequency _{f p} of the. In this embodiment, J = 5.

Next, variation coefficient filter process unit 64 calculates the coefficient of variation _{CV fp} representing the variation of the power in the frequency _{f p} by the equation (14).

Then, the coefficient of variation filter processing unit 64 _{calculates the final evaluation scale CV p} by the equation (15).

Here, CV _Rofp represents the coefficient of variation of ρ times the frequency of the fundamental frequency candidate f _p. For example, the coefficient of variation of a frequency 1/2 octave higher than _{f p (that is, a frequency 1.5 times f p} ) is expressed _{as CV 1.5 fp,} and a frequency one octave higher than _{f p} (that is, 2.0 times _{f p) is expressed as CV 1.5 fp.} The coefficient of variation of (frequency) is expressed _{as CV 2.0 fp.} The function min is a function that returns the smallest value among the arguments.

Variation coefficient filter process unit 64, evaluation measure CV _p determines the fundamental frequency candidate f _p is the minimum as the fundamental frequency of the propulsion engine 110.

When the fundamental frequency is determined by the coefficient of variation filter processing as described above, the rotation speed calculation unit 59 is determined by the coefficient of variation filter processing unit 64 using the equation (4) described in the first embodiment. The rotation speed of the propulsion engine 110 is calculated based on the peak frequency (fundamental frequency).

Incidentally, when the frequency f _p of the fundamental frequency candidate is close to the fundamental frequency of the generator engine 120, by beat phenomenon occurs, it may adversely affect the above variation coefficient filtering. That is, in the frequency domain around the fundamental frequency of the power generation engine 120, the extracted power value fluctuates greatly, and as a result, the value of the coefficient of variation becomes large, and the fundamental frequency of the propulsion engine 110 is accurately determined. Becomes difficult.

Therefore, among the power in the frequency matching the reference value, that divergence from the power average value of the frequency is large, that excluded from the calculation target of the coefficient of variation CV _fp, to calculate the coefficient of variation CV _fp subsequently preferable. For example, before calculating the coefficient of variation CV _fp , the maximum and minimum extracted power values may be excluded from the calculation target. In this case, J in the equation (14) becomes J-2 because two power values are excluded. FIG. 18 (a) shows five power values extracted from the sound frame spectrum, and FIG. 18 (b) excludes the maximum power value (j = 2) and the minimum power value (j = 3) 3 Shows the power values. In this example, the coefficient of variation is calculated using the power values of j = 1, 4, and 5.

As described above, the coefficient of variation filter processing unit 64 obtains the average value of the peak powers of a predetermined number of sound frame spectra before calculating the _{coefficient of variation CV fp, and the predetermined number is based on the deviation width from this average value.} A part of the peak power of is removed from the calculation target of the _{coefficient of variation CV fp. By calculating the coefficient of variation CV fp} after excluding the power values (maximum value, minimum value, etc.) that have a large deviation from the average value, a beat occurs between the noise of the propulsion engine 110 and the power generation engine 120. Even in this case, the influence of noise of the power generation engine 120 can be suppressed, and the fundamental frequency of the propulsion engine 110 can be accurately determined.

<Ship engine speed estimation method>
The processing operation (narrowing process) of the ship engine rotation speed estimation device 1 according to the second embodiment will be described with reference to the flowchart of FIG.

First, the moving average processing unit 61 obtains the moving average spectrum of the average sound frame spectrum, and subtracts the moving average spectrum from the average sound frame spectrum to generate a sound frame difference spectrum (step S21).

Next, the peak extraction unit 62 extracts a plurality of peaks as a second peak group from the sound frame difference spectrum generated in step S21 (step S22).

Next, the multiple frequency processing unit 63 transfers the propulsion engine 110 from the first peak group based on the first peak group extracted in step S16 and the second peak group extracted in step S22. Peaks that are integral multiples and half-integer multiples of the fundamental frequency are extracted (step S23).

Next, the control unit 50A determines whether or not the number of peaks extracted in step S23 is one (step S24). Then, when the number of peaks is one (S24: Yes), the process returns to step S18, and the rotation speed calculation unit 59 determines the rotation speed of the propulsion engine 110 based on the frequency of the peak (specified peak). calculate.

On the other hand, when the number of peaks is a plurality (S24: No), the coefficient of variation filter processing unit 64 performs the coefficient of variation filter processing (step S25). The fundamental frequency is specified by the coefficient of variation filtering. After step S25, the process returns to step S18, and the rotation speed of the propulsion engine 110 is calculated based on the fundamental frequency specified by the coefficient of variation filtering.

As described above, in the second embodiment, the fundamental frequency is specified from the plurality of frequency components included in the passing spectrum described in the first embodiment by performing the multiple frequency processing and the coefficient of variation filtering processing. In the double frequency processing, the candidates for the fundamental frequency are narrowed down by utilizing the knowledge that the power spectrum of the engine sound of the propulsion engine has frequency components that are integral multiples and half-integer multiples of the fundamental frequency. In the coefficient of variation filtering, the fundamental frequency sound is constantly generated, while other sounds (waves, wind, sounds generated by onboard equipment, etc.) are generated and stopped. To narrow down the candidates for the fundamental frequency. Further, even in a situation where the operating frequency of the power generation engine 120 is close to that of the propulsion engine 110 and a beat is occurring, the level fluctuation of the beat frequency component is relatively large, so that the beat frequency component is removed by the coefficient of variation filtering. It is possible.

Therefore, according to the second embodiment, even when a plurality of peaks are included in the first peak group, the peak of the fundamental frequency is specified and the rotation speed of the propulsion engine 110 is estimated with high accuracy. be able to.

As described above, according to the present invention, the rotation speed of the propulsion engine can be accurately estimated from the noise inside the ship. This makes it possible to detect an abnormality in the propulsion engine based on, for example, the speed of the ship and the estimated number of revolutions.

Based on the above description, those skilled in the art may be able to conceive of additional effects and various modifications of the present invention, but the embodiments of the present invention are not limited to the above-described embodiments. Various additions, changes and partial deletions are possible without departing from the conceptual idea and purpose of the present invention derived from the contents defined in the claims and their equivalents.

At least a part of the control units 50 and 50A of the ship engine speed estimation device 1 described in the above-described embodiment may be configured by hardware or software. In the case of software configuration, a program that realizes at least a part of the functions of the control units 50 and 50A may be stored in a recording medium such as a flexible disk or a CD-ROM, read by a computer, and executed. The recording medium is not limited to a removable one such as a magnetic disk or an optical disk, and may be a fixed recording medium such as a hard disk device or a memory.

Further, a program that realizes at least a part of the functions of the control units 50 and 50A may be distributed via a communication line (including wireless communication) such as the Internet. Further, the program may be encrypted, modulated, compressed, and distributed via a wired line or wireless line such as the Internet, or stored in a recording medium.

Further, the ship engine speed estimation device 1 may be configured by a plurality of information processing devices that are communicated with each other. For example, the information processing device communicated with the ship engine speed estimation device 1 may have at least a part of the data processing function of the ship engine speed estimation device 1.

1 Ship engine rotation speed estimation device 10 Sound input unit 20 Information input unit 30 Information output unit 40 Storage unit 50 Control unit 51 Frequency upper limit setting unit 52 Volume filter creation unit 53 Data acquisition unit 54 Fourier conversion unit 55 Spectrum removal unit 56 Average Processing unit 57 Volume filter processing unit 58 Peak extraction unit 59 Rotation speed calculation unit 61 Moving average processing unit 62 Peak extraction unit 63 Multiple frequency processing unit 64 Fluctuation coefficient filter processing unit 100 Ship 110 Propulsion engine 120 Power generation engine 130 Generator 140 Propeller Flim Cutoff frequency LL, UL Limiter line SL Measured volume line SF1 to SF7 Sound frame data

Claims (11)

A ship engine speed estimation device that estimates the speed of a ship's propulsion engine.
A data acquisition unit that acquires sound frame data having a predetermined time width for each predetermined data acquisition time from recorded data that records inboard noise including engine noise of the propulsion engine.
A Fourier transform unit that generates a sound frame spectrum by Fourier transforming the sound frame data,
An averaging processing unit that generates an average sound frame spectrum by averaging a predetermined number of continuous sound frame spectra.
A volume filter created based on a volume profile showing the relationship between the number of revolutions of the propulsion engine and the volume of the inboard noise, and an operating frequency band of the propulsion engine based on the volume of the average sound frame spectrum. And a volume filter processing unit that acquires a passing spectrum that passes through the operating frequency band of the average sound frame spectrum.
A first peak extraction unit that extracts one or more peaks included in the passing spectrum as a first peak group, and a first peak extraction unit.
When the number of peaks included in the first peak group is one, a rotation speed calculation unit that calculates the rotation speed of the propulsion engine based on the frequency of the peak, and a rotation speed calculation unit.
A ship engine speed estimation device, characterized in that it is provided with. Based on the number of cylinders, the number of cycles, and the rated rotation speed of the propulsion engine, the basic frequency at the rated rotation speed of the propulsion engine is calculated, and the upper limit of the frequency to be analyzed is set based on the basic frequency. Setting section and
Before averaging the predetermined number of the sound frame spectra, a spectrum removing unit that removes frequency components above the upper limit of the sound frame spectrum and
The ship engine speed estimation device according to claim 1, further comprising. The ship engine speed estimation device according to claim 1 or 2, wherein the data acquisition time is shorter than the time width of the sound frame data. The ship engine rotation speed estimation device according to any one of claims 1 to 3, wherein the predetermined number of the sound frame spectra is 3 or more. A moving average processing unit that obtains a moving average spectrum of the average sound frame spectrum and generates a sound frame difference spectrum by subtracting the moving average spectrum from the average sound frame spectrum.
A second peak extraction unit that extracts a plurality of peaks as a second peak group from the sound frame difference spectrum, and a second peak extraction unit.
When the first peak group includes a plurality of peaks, the first peak group is an integral multiple of the fundamental frequency of the propulsion engine based on the first peak group and the second peak group. And a multiple frequency processing unit that extracts peaks of half-integer multiples,
Claim 1 is characterized in that when the number of peaks extracted by the multiple frequency processing unit is one, the rotation speed calculation unit calculates the rotation speed of the propulsion engine based on the frequency of the peak. 4. The marine engine speed estimation device according to any one of 4. The ship engine rotation speed estimation device according to claim 5, wherein the moving average processing unit deletes a portion of the sound frame difference spectrum below a predetermined bias line. The multiple frequency processing unit
The product of the first matrix whose element is the reciprocal of the frequency of each peak included in the first peak group and the second matrix whose element is the frequency of each peak included in the second peak group. Calculate and
A third matrix is created by determining whether or not each element of the matrix obtained by the calculation is within the bandwidth of the harmonic band path filter which is an integral multiple or a half-integer multiple of the fundamental frequency. The ship engine speed estimation device according to claim 5 or 6, wherein peaks of integral multiples and half-integer multiples of the fundamental frequency of the propulsion engine are extracted based on the matrix of. When a plurality of peaks are extracted by the multiple frequency processing unit, a coefficient of variation indicating fluctuation of the peak power of the predetermined number of sound frame spectra is calculated for each frequency of each peak, and the coefficient of variation is calculated with respect to the frequency of each peak. Further provided with a coefficient of variation filter processing unit that determines the fundamental frequency of the propulsion engine based on a plurality of calculated coefficient of variation.
The rotation speed calculation unit according to any one of claims 5 to 7, wherein the rotation speed calculation unit calculates the rotation speed of the propulsion engine based on the frequency of the peak determined by the coefficient of variation filtering unit. Ship engine speed estimation device. Before calculating the coefficient of variation, the coefficient of variation filtering unit obtains an average value of the peak powers of the predetermined number of sound frame spectra, and based on the deviation width from the average value, the predetermined number of peak powers. The ship engine rotation speed estimation device according to claim 8, wherein a part of them is removed from the calculation target of the coefficient of variation. A method for estimating the number of revolutions of a ship engine, which estimates the number of revolutions of a ship's propulsion engine.
A step of acquiring sound frame data having a predetermined time width at a predetermined data acquisition time from the recorded data obtained by recording the inboard noise including the engine sound of the propulsion engine.
A step of generating a sound frame spectrum by Fourier transforming the sound frame data,
A step of generating an average sound frame spectrum by averaging a predetermined number of consecutive sound frame spectra.
A volume filter created based on a volume profile showing the relationship between the number of revolutions of the propulsion engine and the volume of the inboard noise, and an operating frequency band of the propulsion engine based on the volume of the average sound frame spectrum. And the step of acquiring the passing spectrum passing through the operating frequency band in the average sound frame spectrum.
A step of extracting one or more peaks included in the passing spectrum as a first peak group, and
When the number of peaks included in the first peak group is one, the step of calculating the rotation speed of the propulsion engine based on the frequency of the peak, and
A method for estimating the number of revolutions of a ship engine, which comprises. A ship engine speed estimation program for estimating the speed of a ship's propulsion engine.
A step of acquiring sound frame data having a predetermined time width at a predetermined data acquisition time from the recorded data obtained by recording the inboard noise including the engine sound of the propulsion engine.
A step of generating a sound frame spectrum by Fourier transforming the sound frame data,
A step of generating an average sound frame spectrum by averaging a predetermined number of consecutive sound frame spectra.
A volume filter created based on a volume profile showing the relationship between the number of revolutions of the propulsion engine and the volume of the inboard noise, and an operating frequency band of the propulsion engine based on the volume of the average sound frame spectrum. And the step of acquiring the passing spectrum passing through the operating frequency band in the average sound frame spectrum.
A step of extracting one or more peaks included in the passing spectrum as a first peak group, and
When the number of peaks included in the first peak group is one, the step of calculating the rotation speed of the propulsion engine based on the frequency of the peak, and
A ship engine speed estimation program that causes a computer to execute.

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