Device and method for estimating rotational speed of gearbox based on vibration signal

Abstract

According to one embodiment of the present invention, a speed estimation device may comprise: a converter configured so as to convert a vibration signal acquired from a gear box into a time-frequency representation (TFR); and a generator configured to select a first apex at a first unit time on the basis of the energy value of each apex in the TFR, and to generate information on the operating speed of the machine provided with the gearbox by connecting the first apex to a second apex located at a second unit time.

Description

Technical Field

[0001] The present invention relates to a speed estimation device and method, that is, to a device and method for estimating the rotation speed of a gear box based on a vibration signal in a non-stationary state obtained from the gear box. Background Art

[0002] Typically, when acquiring vibration data of a mechanical system under variable speed operating conditions, a vibration signal in a non-stationary state is observed. Typically, a mechanical system with variable speed operating conditions can use an encoder to confirm the vibration tendency. However, the signal obtained from the encoder often has a different sampling rate from the vibration signal, and when the encoder and the vibration sensor are not in the same location, additional work such as mechanical mechanism to reset the effect of the set operating speed on the vibration signal needs to be considered.

[0003] In order to solve such a problem, as an encoderless vibration data extraction method, a method of demodulating the frequency modulated signal in the vibration signal is performed, or a method of confirming the frequency variability by using a time-frequency ridge model is adopted, based on which a method of confirming the change trend of the vibration data caused by the phase change of the operation is confirmed. However, since the demodulation technology usually works effectively for a single-component signal, it is like a mechanical system that detects harmonics in multiple directions, and when there is a frequency overlap between other different component signals due to noise, it tends to have very poor performance. Therefore, further signal filtering technology is required. In addition, in the case of ridge extraction technology, physical information must be known in advance to identify effective signals, and due to various limitations such as the overlap of the ridge itself and noise problems, it is often difficult to apply in practice.

[0004] On the other hand, there is also a method of directly acquiring a speed profile from a gearbox using an encoder or an inertial measurement unit (IMU). However, when analyzing a vibration signal through a speed profile acquired from an encoder or an IMU, there is a problem of errors due to time-delay between vibration sensors, frequency shifting during signal transmission, and the like.

[0005] Prior art literature

[0006] Patent Literature

[0007] Korean Patent Publication No. 10-2021-0108156 (Publication Date: September 2, 2021) Summary of the invention

[0008] Technical issues

[0009] The technical object of the present invention is to provide an apparatus and method capable of estimating the rotation speed of a gear box without an encoder by utilizing a vibration signal in a non-stationary state acquired from the gear box.

[0010] Another aspect of the present invention is to provide a speed estimating device and method capable of acquiring an accurate and robust speed curve diagram of a gearbox.

[0011] The problems to be solved by the present invention are not limited to the above contents, and other problems to be solved that are not described will be clearly understood by those skilled in the art from the following description.

[0012] Technical Solution

[0013] According to one embodiment of the present invention, the speed estimation device may include: a converter, which is configured to convert a vibration signal obtained from a gear box into TFR (Time-Frequency Representation); and a generator, which is configured to select a vertex in a first unit time based on the energy value of the vertex in the TFR, and generate speed information for the gear box by connecting the first vertex with a second vertex located in a second unit time.

[0014] The generator may set the selectable areas for the first vertex and the second vertex in the TFR using a GMF (Gear Mesh Frequency) of the gear box based on a speed signal measured in the gear box.

[0015] Furthermore, the generator may select a vertex having the highest energy value from among the vertices within the selectable area during the first unit time as the first vertex.

[0016] In addition, the generator can derive the weight of the line segment connecting two vertices within the TFR based on the energy value of each vertex located in the selectable area and at least one of the set acceleration allowable range, and based on the weight, select the second vertex from the vertices of the second unit time located in the selectable area.

[0017] In addition, the generator may select, based on the weight, a vertex having an energy value greater than a first critical value from among the vertices of the second unit time located in the selectable area as a candidate vertex for the second vertex.

[0018] Furthermore, the generator may select, from among the candidate vertices, a candidate vertex that is within the acceleration allowable range as a candidate vertex for the second vertex based on the weight.

[0019] In addition, the generator may select, from candidate vertices within the acceleration allowable range, a vertex whose energy value has an energy value different from that of the first vertex by less than a second critical value as the second vertex based on the weight.

[0020] Furthermore, the generator may repeat a process of connecting vertices within the TFR to respectively generate velocity information of component signals of the vibration signal, and generate a velocity profile by adding each of the generated velocity information.

[0021] Furthermore, the generator may change energy values ​​of a vertex and vertices adjacent to the vertex selected in the process of generating the velocity information of the first component signal among the component signals, and then generate the velocity information of the second component signal based on the changed energy values.

[0022] Furthermore, the generator may generate the speed curve graph by analyzing a correlation between each of the speed information and excluding speed information of component signals having a correlation below a critical value.

[0023] According to another embodiment of the present invention, the speed estimation method may include:

[0024] The steps of converting a vibration signal obtained from a gearbox into a TFR; selecting a first vertex in a first unit time based on an energy value of a vertex in the TFR; and generating speed information of the gearbox by connecting the first vertex with a second vertex located at a second unit time.

[0025] According to another embodiment of the present invention, a computer program stored in a computer-readable recording medium may include instructions for causing the processor to perform a speed estimation method when executed by the processor, the speed estimation method including: a step of converting a vibration signal acquired from a gearbox into a TFR; a step of selecting a first vertex in a first unit time based on an energy value of a vertex in the TFR; and a step of generating speed information of the gearbox by connecting the first vertex with a second vertex located at a second unit time.

[0026] Effects of the Invention

[0027] According to an embodiment of the present invention, even without an encoder, the rotation speed of the gear box can be estimated by using a vibration signal in a non-stationary state obtained from the gear box.

[0028] According to one embodiment of the present invention, since accurate and robust speed data can be obtained from the gearbox, the condition of the machinery equipped with the gearbox can be monitored, and even if the signal changes due to the operating environment, the difference between the vibration signals caused by the operating phase difference can be reduced, thereby reducing false sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a diagram showing a speed estimating device according to an embodiment of the present invention.

[0030] Figure 2 is a diagram illustrating a process of converting a vibration signal into a time-frequency domain according to an embodiment of the present invention.

[0031] Figure 3 is a diagram illustrating a process of generating speed information according to an embodiment of the present invention.

[0032] Figure 4 FIG. 1 is a diagram illustrating a process of setting an area in which vertices can be selected according to an embodiment of the present invention.

[0033] Figure 5 and Figure 6 is a diagram illustrating a process of connecting vertices according to an embodiment of the present invention.

[0034] Figure 7 This is a diagram showing a process of repeatedly extracting velocity information of each component signal of a vibration signal by the velocity estimating device according to one embodiment of the present invention.

[0035] Figure 8 It is a diagram showing a process of generating a speed graph according to an embodiment of the present invention.

[0036] Fig. 9 It is a diagram showing a speed estimation method according to an embodiment of the present invention.

[0037] Reference numerals

[0038] 100: speed estimation device, 110: converter, 115: vibration sensor, 120: generator, 125: IMU, 150: gear box. DETAILED DESCRIPTION

[0039] The advantages and features of the present invention, and methods for achieving them will become clear by reference to the embodiments described below in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms. This embodiment is provided only to make the disclosure of the present invention complete and to fully inform the scope of the invention to those skilled in the art. The present invention is defined only by the scope of the claims. Therefore, in some embodiments, well-known processing steps, well-known component structures, and well-known technologies are not described in detail to avoid the present invention being interpreted in an ambiguous manner.

[0040] The terms used in this specification are selected from the currently widely used general terms as much as possible in consideration of the functions in the present invention, but this may be different according to the intention of those skilled in the art, precedents, the emergence of new technologies, etc. In addition, in certain cases, there are also terms arbitrarily selected by the applicant, in which case, their meanings will be described in detail in the description of the corresponding invention. Therefore, the terms used in this specification should be interpreted based on the meaning of the terms and the overall content of the present invention, rather than simply based on the names of the terms.

[0041] Throughout the present specification, when it is mentioned that a certain part “includes” a certain constituent element, unless otherwise described, it means that other constituent elements are not excluded and other constituent elements may also be included.

[0042] In addition, terms such as "unit", "module", etc. used in this specification may refer to hardware components such as software or FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and "unit", "module", etc. perform at least one function or action. However, "unit", "module", etc. are not limited to the meaning of software or hardware. "Unit", "module", etc. can be configured to reside on an addressable storage medium, and can also be configured to be reproduced on one or more processors. Therefore, as an example, "unit", "module", etc. include software components, object-oriented software components, components such as class components and task components, procedures, functions, attributes, processes, subroutines, fragments of program code, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays, and variables. The components of the present invention and the functions provided by "units", "modules", etc. can be combined into a smaller number of components, "units", "modules", etc., or can be further separated into "units", "modules", etc.

[0043] In addition, in this specification, the terms "first", "second", "third" and the like may be used to describe various components, but these components are not limited by these terms. The purpose of using these terms is to distinguish one component from other components.

[0044] The embodiments of the present invention are described in detail below with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. In addition, in the accompanying drawings, parts that are not related to the description are omitted to clearly illustrate the present invention. Throughout the specification, the same reference numerals refer to the same constituent elements.

[0045] Figure 1 It is a diagram showing a speed estimating device according to an embodiment of the present invention.

[0046] Reference Figure 1 A speed estimation device 100 according to an embodiment of the present invention includes a receiver 110 , a converter 120 , and a generator 130 .

[0047] The receiver 110 may be configured to receive a vibration signal measured by a vibration sensor 151 provided in the gearbox 150 and an acceleration signal and / or an angular velocity signal measured by an inertial measurement unit 152 (IMU). The vibration signal obtained from the gearbox 150 may be a non-stationary signal. A non-stationary signal may refer to a signal whose frequency property or characteristic changes over time due to the gearbox 150 running at a variable speed. The gearbox 150 is a device including a plurality of gears for power transmission, and may be used interchangeably with terms such as a gearbox and a gear set.

[0048] As an example, when the speed estimation device 100 of an embodiment of the present invention is used to generate a speed curve diagram of a planetary gearbox provided in a gyratory portion of an engineering machine such as an excavator, the receiver 110 may be configured to receive a vibration signal, a speed signal, etc. measured in the corresponding planetary gearbox from a vibration sensor 151, an IMU 152, etc. based on a wired or wireless communication method. However, the present invention is not limited thereto, and may be used to obtain a speed curve diagram of any machine provided with a gearbox.

[0049] The converter 120 may be configured to convert a non-stationary vibration signal obtained from the gearbox 150 through the receiver 110 into a TFR (Time-Frequency Representation). As an example, the converter 120 may generate a TFR representing the vibration signal in a time-frequency domain by removing noise from the vibration signal and performing a STFT (Short Time Fourier Transform). The TFR may be used interchangeably with terms such as image and spectrogram.

[0050] The generator 130 may be configured to select a first vertex in a first unit time based on the energy value of the vertex in the TFR generated by the converter 120, and generate speed information (or speed estimation information) of the gearbox 150 by performing a process of connecting the first vertex with a second vertex located at a second unit time. To this end, the generator 130 may replace or regard each index of the TFR generated by the converter 120 as a vertex. In addition, the speed information may be generated by calculating an optimal path through a process of selecting or determining a line segment to connect each vertex.

[0051] For example, the generator 130 can set a selectable area for the first vertex and the second vertex in the TFR using the GMF (Gear Mesh Frequency) of the gearbox 150 based on the signal obtained from the IMU 152 through the receiver 110. Therefore, when the generator 130 calculates the path to connect the vertices, the range of selectable vertices can be limited to vertices located between the upper limit and the lower limit set by the GMF of the gearbox 150 based on the speed signal measured by the gearbox 150. The generator 130 can select the vertex with the highest energy value from the vertices located in the first unit time within the selectable area as the first vertex. The first vertex may refer to the vertex at index (0, p) in the TFR. That is, when the generator 130 selects the first vertex in the TFR, it can select the vertex with the highest energy value in the selectable area as the first vertex.

[0052] On the other hand, the generator 130 can derive the weight of the line segment connecting two vertices in the TFR (hereinafter referred to as the node weight) based on the energy value of each vertex located in the selectable area and at least one of the set acceleration allowable ranges, and based on this, select the second vertex from the vertices of the second unit time located in the selectable area. The second vertex may refer to the vertex with index (1, p) located in the TFR. That is, when the generator 130 selects the second vertex to be connected to the first vertex in the TFR, it can use the node weight derived based on the energy value of the vertex located in the selectable area and / or the acceleration allowable range to limit the range or position of the vertices that can be selected as the second vertex.

[0053] For example, the generator 130 may select, based on the node weight, vertices whose energy values ​​are greater than the first critical value among the vertices located in the second unit time within the selectable area and / or vertices located in the acceleration allowable range as candidate vertices for the second vertex, and select vertices whose energy values ​​among the candidate vertices have a difference with the energy value of the first vertex that is less than the second critical value as the second vertex. The first critical value may be set based on the average energy value of the vertices located in the second unit time, and the second critical value may be set based on the average value of the difference between the energy value of the first vertex and the energy values ​​of each vertex located in the second unit time. As an example, the first critical value may be set to be greater than the average energy value of the vertices located in the second unit time, and the second critical value may be set to be less than the average value of the difference between the energy value of the first vertex and the energy values ​​of each vertex located in the second unit time.

[0054] The generator 130 may repeat the process of connecting two vertices in this way until the first vertex in the TFR is connected to the last vertex, thereby generating speed information. In addition, the generator 130 may repeat the process of generating speed information for each component signal of the vibration signal, and generate a speed profile based on each speed information generated thereby. At this time, the generator 130 may change the energy value of the vertex selected and the vertex adjacent to the vertex in the process of generating the speed information of the first component signal, and generate the speed information of the second component signal based on the changed energy value. The second component signal may be a signal of a higher order than the first component signal.

[0055] For example, the energy values ​​of the vertex selected in the process of generating the speed information of the first component signal and the vertices adjacent to the vertex can be set to values ​​lower than the energy values ​​of the vertices corresponding to the second component signal when generating the speed information of the second component signal, or replaced or set to 0.

[0056] When a plurality of velocity information is generated for the component signals of the vibration signal, the generator 130 may analyze the correlation between each of the velocity information and exclude velocity information of the component signals having a correlation below a critical value to generate a velocity graph.

[0057] Figure 2 is a diagram illustrating a process of converting a vibration signal into a time-frequency domain according to an embodiment of the present invention.

[0058] The speed estimation device of an embodiment of the present invention can convert the domain of the vibration signal received from the gear box into the time-frequency domain by using CWT (Continuous Wavelet Transform), STFT, etc.

[0059] As an example, the speed estimation device may express the vibration signal in the time-frequency domain by performing STFT on the vibration signal, as shown in the following equation 1.

[0060]

Formula 1

[0061] X s (τ,ω)=∫s(t)w(t-τ)e -jωt dt

[0062] Where S(t) represents the vibration signal, τ and ω represent the time domain index and frequency domain index respectively, and w is the window function.

[0063] The TFR generated by the STFT can be called a spectrogram, and the energy of the vibration signal in the TFR can be represented by multiplying the vibration signal Xs calculated in the time-frequency domain by the complex conjugate signal, as shown in the following formula 2.

[0064]

Formula 2

[0065] C s (τ,ω)=X s (τ,ω)X s * (τ,ω)

[0066] The speed estimation device can Figure 2 Each index (i, j) in the TFR obtained as shown is regarded as a vertex, and the speed information of the vibration signal is generated by connecting the vertices selected at each unit time.

[0067] Figure 3 is a diagram illustrating a process of generating speed information according to an embodiment of the present invention.

[0068] Reference Figure 3According to an embodiment of the present invention, in order to extract the velocity information of the vibration signal in the TFR, a line segment (or trunk line) connecting two different vertices in the TFR may be determined. For example, the velocity estimation device may be based on a path exploration algorithm such as the Dijkstra algorithm, such as Figure 3 As shown, the node weight of the line segment connected to the vertex at index (i+1, p) is derived based on the first vertex 310 at index (i, j) in the TFR, and the speed information is generated by repeatedly connecting the node weight of the line segment of the selected second vertex 320 and the vertex at index (i+2, p) based on the node weight and calculating the shortest path connecting each vertex 310, 320, and 330.

[0069] When the first vertex 310 is the first vertex in the TFR, that is, the first vertex 310 is located at the first unit time corresponding to the index (0, p) in the TFR, the velocity estimation device can select the vertex with the highest energy value in the first unit time as the first vertex. The index or position of the second vertex 320 and the third vertex 330 can be determined or selected based on the node weight. Among them, the node weight is used to limit the selectable range or position of the vertex (end point) connected to the vertex (starting point) serving as the reference. For this reason, in the present invention, multiple node weights can be used individually or comprehensively.

[0070] Refer to the following Figures 4 to 6 The process of generating speed information by calculating the connection path between vertices in the speed estimation device according to one embodiment of the present invention will be described in more detail.

[0071] Figure 4 FIG. 1 is a diagram illustrating a process of setting an area in which vertices can be selected according to an embodiment of the present invention.

[0072] Reference Figure 4 The speed estimation device of one embodiment of the present invention can limit the range of vertices that can be selected when calculating the path based on the speed signal (e.g., acceleration signal, angular velocity signal, etc.) measured in the gearbox and the GMF of the gearbox. As an example, the speed signal can be measured by a speed measuring device such as a speed sensor, an acceleration sensor, an IMU, etc.

[0073] For example, the speed estimation device may set a boundary based on a signal as shown in the following equation 3.

[0074]

Formula 3

[0075] s I (t, α, β) = (1 + α) s I (t-β)

[0076] b u (t) = max A {f GMF S I (t,α,β)}, A={(α,β)||α|≤α p , |β|≤β p}

[0077] b l (t) = max{min A {f GMF s I (t,α,β)},0}, A={(α,β)||α|≤α p , |β|≤β p}

[0078] Among them, S I represents the signal obtained from the IMU, α and β represent S I The permissible error range in % of the frequency unit and the permissible error range in time (e.g., seconds) of the time unit. GMF is to calculate S I Physical constant that is multiplied by the GMF.

[0079] S I It can be calculated in the IMU and input to the velocity estimation device, or derived by the velocity estimation device based on the angular velocity signal and / or acceleration signal received from the IMU. u b1(t) represents the upper limit 410 of vertices for which path calculation is to be performed, and b1(t) represents the lower limit 420 of vertices for which path calculation is to be performed.

[0080] The speed estimation device can be used by using the position located by b u The velocity information is generated by calculating the path of vertices within the range limited by b(t) and b1(t). u The area between b1(t) and b1(t) can be defined as the selectable area of ​​the vertex.

[0081] Since the signal obtained from the IMU has time delay, frequency shift during signal transmission, etc., it is difficult to accurately estimate the speed. Therefore, the speed estimation device can impose the following constraints when connecting the vertices by inversely calculating the results obtained from the IMU.

[0082] Figure 5 and Figure 6 is a diagram illustrating a process of connecting vertices according to an embodiment of the present invention.

[0083] First, refer to Figure 5, the speed estimating device can calculate the first node weight based on the energy value of each vertex within a range set based on the speed signal measured in the gear box (a selectable area for the vertex).

[0084] For example, in order to select or determine the end point from the vertex at index (i+1, p) based on the vertex at index (i, j) in TFR, the speed estimation device can calculate the first node weight as shown in the following formula 4.

[0085]

Formula 4

[0086]

[0087] Among them, C represents the energy value of the corresponding vertex.

[0088] Referring to Formula 4, the line segment connecting the starting point (i, j) and the end point (i+1, p) has a weight for vertices with relatively high energy. The energy value of the vertex existing in the position corresponding to the vibration signal in the TFR is greater than the energy values ​​of the surrounding vertices. Therefore, the speed estimation device can derive the vertex 520 with a higher energy value among the vertices located at the index (i+1, p) as a candidate vertex to be connected to the first vertex 510 located at the index (i, j) based on Formula 4. As an example, when the second vertex 521 located at the index (i+1, j) is selected from the candidate vertices 520, the speed estimation device can determine the vertex 530 with a higher energy value among the vertices located at the index (i+2, p) as a candidate vertex to be connected to the second vertex 521 based on the first node weight.

[0089] On the other hand, the speed estimation device may calculate the second node weight based on the acceleration allowable range within the range set based on the speed signal measured in the gear box. For example, in order to select the end point 620 from the vertex located at the index (i+1, p) based on the starting point 610 located at the index (i+1, p), the speed estimation device may calculate the second node weight as shown in the following formula 5.

[0090]

Formula 5

[0091]

[0092] Referring to Formula 5, the starting point is used as the weight for the line segment connecting (i, j) and the end point (i+1, p), that is, the range of vertices that can be selected as the end point is determined by the value of K. The value of K can be derived based on Formula 6 below.

[0093]

Formula 6

[0094]

[0095] Among them, p ais a constant and a parameter that determines the allowable range of acceleration. The frequency resolution and time resolution can be determined by the window length and FFT parameters respectively.

[0096] For the frequency of the vibration signal, the acceleration changes within a certain range over time. Therefore, the speed estimation device can set the permissible acceleration range (acceleration permissible range) for the unit time after the current unit time in TFR based on equations 5 and 6, and derive the vertex located in the acceleration permissible range among the vertices at index (i+1, p) as candidate vertices for the end point.

[0097] As an example, refer to Figure 6 , when the K value is 1, the candidate vertices that can be connected to the starting point 610 at index (i, j) in the TFR can be limited to the range of index (i+1, j-1) to index (i+1, j+1). When the K value is 2, the candidate vertices that can be connected to the starting point 610 at index (i, j) can be limited to the range of index (i+1, j-3) to index (i+1, j+3). That is, the end point 620 can be selected from the range limited by the K value.

[0098] Furthermore, the speed estimating means may calculate the third node weight based on the allowable energy variation amount within a range set based on the speed signal measured in the gear box.

[0099] In TFR, if it is the same component signal, the energy does not change much over time. Therefore, the speed estimation device can divide the energy difference between the two vertices (starting point and end point) by the noise level as shown in the following equation 7, and normalize it to a value between 0 and 1 using an inverse normal function.

[0100]

Formula 7

[0101]

[0102] The speed estimation device may select, based on the third node weight as shown in Formula 7, a vertex whose energy value has an energy value different from that of the first vertex and is less than a second critical value as the second vertex.

[0103] On the other hand, the speed estimation device can perform path calculation based on at least one of the above-mentioned first node weight to the third node weight, or perform path calculation based on the final weight of adding the first node weight to the third node weight as shown in the following formula 8.

[0104]

Formula 8

[0105] nw t (i, j, i+1, p) = γi nw i (i,j,i+1,p) / (γ1+γ2+γ3)

[0106] When path calculation is performed based on the final weight of Formula 8, the range of path selection is limited compared to when path calculation is performed based on any one of the first to third node weights, so speed information can be extracted from the vibration signal faster and more accurately.

[0107] Figure 7 This is a diagram showing a process of repeatedly extracting velocity information of each component signal of a vibration signal by the velocity estimating device according to one embodiment of the present invention.

[0108] Reference Figure 7 The speed estimation device can extract the speed information of each component signal by repeatedly executing the above-mentioned path exploration process for each component signal of the vibration signal. At this time, the speed estimation device can change the energy value of the vertex selected in the process of generating the speed information of the first component signal and the vertex adjacent to the vertex, and generate the speed information of the second component signal based on the changed energy value.

[0109] The vibration signal may include n component signals, and in TFR, the energy of the vertex corresponding to the i-order component signal is higher than the energy of the vertex corresponding to the i+1-order component signal. Therefore, the speed estimation device may prevent a result similar to the speed information of the i-order component signal from occurring when generating the speed information of the i+1-order component signal by setting the energy values ​​of the selected vertex and the vertices adjacent to the vertex to values ​​lower than the energy values ​​of the vertices corresponding to the i+1-order component signal, or by replacing or setting the energy values ​​of the selected vertex and the vertices adjacent to the vertex to 0 in the process of generating the speed information of the i+1-order component signal.

[0110] As an example, the speed estimation device can remove the following equation 9: Figure 7 The vertex and its surrounding vertices selected when generating the velocity information of the component signal of the vibration signal are shown.

[0111]

Formula 9

[0112]

[0113] Among them, e (ic) (i) represents the velocity information of the i-th (i-order) component signal, p j is a parameter for removing all vertices and their surrounding vertices corresponding to the i-th component signal from the TFR. As an example, the Pj value can be set to 2. (ic)(i, j) represents the energy at the TFR index (i, j) used in the ic-th repetition process, and ic=1 represents the speed information of the vibration signal (basic signal).

[0114] Figure 8 It is a diagram showing a process of generating a speed graph according to an embodiment of the present invention.

[0115] like Figure 8 As shown, when generating a plurality of speed information for the component signal of the vibration signal, the speed estimation device can add each speed information to generate a speed curve. At this time, the speed estimation device can analyze the correlation between each speed information based on the following formula 7, and exclude the speed information of the component signal whose correlation is below the critical value when generating the speed curve.

[0116]

Formula 10

[0117] Corr([e (1) (i), e (2) (i), e (3) (i), ..., e (n) (i)]) = CX

[0118] η={ic|max(CX ic，* )>p mic}

[0119]

[0120] Among them, p mic To determine the parameters of the component signal with the lowest correlation based on the correlation between the component signals, N ic Represents the total number of elements in the array n.

[0121] Fig. 9 It is a diagram showing a speed estimation method according to an embodiment of the present invention.

[0122] Reference Fig. 9 The speed estimation device of one embodiment of the present invention can convert a vibration signal obtained from a gearbox into a TFR (S900). To this end, the speed estimation device can receive a vibration signal from a vibration sensor provided in the gearbox. The vibration signal can be a vibration signal in a non-steady state. The non-steady state vibration signal can be measured when a machine equipped with the gearbox runs at a variable speed.

[0123] The speed estimation device can replace the index (i, j) in the TFR with or regard it as a vertex, and select the first vertex in the first unit time based on the energy value of the vertex (S910), and generate the speed information of the gearbox by repeatedly executing the process of connecting the first vertex with the second vertex located in the second unit time until the nth vertex located in the nth unit time is connected (S920). At this time, the speed estimation device can set the selectable area of ​​the first vertex and the second vertex in the TFR based on the speed signal measured in the gearbox. For example, the speed estimation device can use the signal obtained from the IMU and the GMF of the gearbox to limit the range of selectable vertices (selectable area for vertices) when performing the path calculation for extracting the speed information in the TFR. In addition, the speed estimation device can select the vertex with the highest energy value from the vertices in the first unit time located in the selectable area as the first vertex. Among them, the first vertex can refer to the vertex of the index (0, p) located in the TFR. In addition, the speed estimation device can derive the weight of the line segment connecting the start point and the end point within the TFR based on the energy value of each vertex located in the selectable area and at least one of the set acceleration allowable ranges, and based on this, select the second vertex from the vertices of the second unit time located in the selectable area.

[0124] For example, the speed estimation device can be based on Figure 5 and Figure 6 The above-mentioned at least one weight is used to select vertices whose energy values ​​are greater than the first critical value and / or vertices located in the acceleration allowable range from the vertices located in the second unit time within the selectable area as candidate vertices for the second vertex, and select vertices whose energy values ​​differ from the energy value of the first vertex by less than the second critical value from the candidate vertices as the second vertex.

[0125] The speed estimation device may generate speed information of the vibration signal by repeatedly executing the process of connecting the starting point and the end point in the TFR until connecting from the first vertex in the TFR to the last vertex. In addition, the speed estimation device may repeatedly execute the process of generating speed information for at least one of the component signals of the vibration signal, and generate a speed curve of the gearbox based on the speed information generated thereby. At this time, the speed estimation device may change the energy value of the vertex selected in the process of generating the speed information of the first component signal and the vertex adjacent to the vertex, and then generate the speed information of the second component signal based on the changed energy value.

[0126] For example, the speed estimation device may set the energy value of the vertex selected in the process of generating the speed information of the first component signal and the vertex adjacent to the vertex to a value lower than the energy value of the vertex corresponding to the second component signal, or replace or set the energy value of the vertex to 0, so as to remove the vertex from the TFR. In addition, the speed estimation device may analyze the correlation between the speed information of each component signal of the vibration signal, and exclude the speed information of the component signal whose correlation is below a critical value to generate the speed curve graph.

[0127] On the other hand, each step included in the speed estimating method performed by the speed estimating apparatus of the aforementioned embodiment may be implemented as a computer program including instructions for causing a processor to execute the steps.

[0128] Furthermore, each step included in the speed estimating method performed by the speed estimating apparatus of the aforementioned embodiment may be implemented in a computer-readable recording medium storing a computer program including instructions for causing a processor to execute the steps.

[0129] The combination of each step in the flowchart attached to the present invention can be executed by computer program instructions. Since these computer program instructions can be mounted on a processor of a general-purpose computer, a special-purpose computer or other programmable data processing device, the instructions executed by the processor of the computer or other programmable data processing device generate means for executing the functions described in each step of the flowchart. These computer program instructions can also be stored on a computer-usable or computer-readable recording medium, which can point to a computer or other programmable data processing device to implement the function in a specific manner, and the instructions stored in the computer-usable or computer-readable recording medium can also produce a manufacturing item containing the instruction means for executing the functions described in each step of the flowchart. The computer program instructions can also be mounted on a computer or other programmable data processing device, so that a series of action steps are performed on the computer or other programmable data processing device and a process executed by the computer is generated, so that the instructions for executing the computer or other programmable data processing device can also provide steps for executing the functions described in each step of the flowchart.

[0130] In addition, each step may represent a module, a fragment or a part of a code including one or more executable instructions for performing a specified logical function. In addition, the functions described in the steps in several alternative embodiments may not occur in sequence. For example, two steps connected to the diagram may be performed substantially simultaneously, or sometimes these steps may be performed in reverse order according to the corresponding functions.

[0131] The above description is merely an exemplary description of the technical idea of ​​the present invention, and those skilled in the art will be able to make various modifications and variations within the scope of the essential purpose of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of ​​the present invention, but are for illustrative purposes, and the scope of the technical idea of ​​the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted according to the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as falling within the scope of the rights of the present invention.

Claims

1. A speed estimation device, characterized in that: include: A converter configured to convert a vibration signal obtained from the gearbox into a TFR, i.e., a time frequency representation; as well as A generator is configured to select a first vertex at a first unit time based on energy values ​​of the vertices in the TFR, and generate speed information for the gearbox by connecting the first vertex with a second vertex at a second unit time.

2. The speed estimation device according to claim 1, characterized in that: The generator sets selectable regions for the first vertex and the second vertex in the TFR using the GMF, ie, the gear meshing frequency, of the gearbox based on a speed signal measured in the gearbox.

3. The speed estimation device according to claim 2, characterized in that: The generator selects a vertex with the highest energy value from among the vertices within the selectable area during the first unit time as the first vertex.

4. The speed estimation device according to claim 2, characterized in that: The generator derives the weight of the line segment connecting two vertices within the TFR based on the energy value of each vertex located in the selectable area and at least one of the set acceleration allowable ranges, and selects the second vertex from the vertices of the second unit time located in the selectable area based on the weight.

5. The speed estimation device according to claim 4, characterized in that: The generator selects, based on the weight, vertices having energy values ​​greater than a first critical value from among the vertices within the selectable area during the second unit time as candidate vertices for the second vertex.

6. The speed estimation device according to claim 5, characterized in that: The generator selects, from among the candidate vertices, candidate vertices that are within the acceleration allowable range as candidate vertices for the second vertex based on the weight.

7. The speed estimation device according to claim 6, characterized in that: The generator selects, from candidate vertices within the acceleration allowable range, a vertex whose energy value has an energy value different from that of the first vertex by less than a second critical value as the second vertex based on the weight.

8. The speed estimation device according to claim 1, characterized in that: The generator repeats a process of connecting vertices within the TFR to respectively generate velocity information of component signals of the vibration signal, and generates a velocity graph by adding each of the generated velocity information.

9. The speed estimation device according to claim 8, characterized in that: The generator changes energy values ​​of a vertex and vertices adjacent to the vertex selected in the process of generating velocity information of a first component signal among the component signals, and then generates velocity information of a second component signal based on the changed energy values.

10. The speed estimation device according to claim 8, characterized in that: The generator generates the speed curve graph by analyzing the correlation between each of the speed information and excluding the speed information of the component signals having the correlation below a critical value.

11. A speed estimation method, characterized in that: include: The step of converting the vibration signal obtained from the gearbox into TFR, which is a time frequency representation; The step of selecting a first vertex in a first unit time based on energy values ​​of the vertices in the TFR; as well as A step of generating speed information of the gear box by connecting the first vertex with a second vertex located at a second unit time.

12. The method according to claim 11, characterized in that After the conversion step, the method further comprises: The step of setting selectable regions for the first vertex and the second vertex in the TFR using the GMF, ie, the gear meshing frequency, of the gearbox based on a speed signal measured in the gearbox.

13. The method according to claim 12, characterized in that The steps of selecting include: A step of selecting a vertex with the highest energy value from among the vertices within the selectable area during the first unit time as the first vertex.

14. The method according to claim 12, characterized in that The steps of selecting include: A step of deriving a weight of a line segment connecting two vertices in the TFR based on at least one of an energy value of each vertex located in the selectable region and a set acceleration allowable range; and A step of selecting the second vertex from among the vertices of the second unit time located within the selectable area based on the weight.

15. The method according to claim 14, characterized in that The steps of selecting include: A step of selecting, based on the weight, candidate vertices having energy values ​​greater than a first critical value and located in the acceleration allowable range from among the vertices of the second unit time located in the selectable area as candidate vertices for the second vertex.

16. The method according to claim 15, characterized in that The steps of selecting include: Based on the weight, a step of selecting a vertex from the candidate vertices, the difference between the energy value of the first vertex and the energy value of the first vertex being less than a second critical value, as the second vertex.

17. The method according to claim 11, characterized in that The generating steps include: Repeating the process of connecting the vertices in the TFR to respectively generate velocity information of the component signals of the vibration signal; and A step of generating a speed profile by adding each of the generated speed information.

18. The method according to claim 17, characterized in that The step of generating speed information of the component signal of the vibration signal comprises: A step of changing energy values ​​of a vertex selected in the process of generating speed information of a first component signal among the component signals and vertices adjacent to the vertex; and The step of generating speed information of a second component signal based on the changed energy value.

19. The method according to claim 17, characterized in that The steps of generating the speed curve graph include: The step of analyzing the correlation between each of the speed information and excluding the speed information of the component signal having a correlation below a critical value.

20. A computer program stored in a computer-readable recording medium, characterized in that The computer program comprises instructions for causing a processor to perform a speed estimation method when the computer program is executed by the processor. The speed estimation method comprises: The step of converting the vibration signal obtained from the gearbox into TFR, which is a time frequency representation; A step of selecting a first vertex in a first unit time based on energy values ​​of the vertices in the TFR; and A step of generating speed information of the gear box by connecting the first vertex with a second vertex located at a second unit time.

Images