Inspection device

Abstract

A processor of this inspection device executes processing including: acquiring a sound signal of a percussion instrument sound in a first time; calculating a power density corresponding to the time and frequency in the first time; dividing the maximum value of the power density on the high frequency side greater than or equal to a preset frequency threshold by the effective value of the power density in the first time on the high frequency side to calculate a crest factor on the high frequency side; dividing the maximum value of the power density on the low frequency side less than the frequency threshold by the effective value of the power density in the first time on the low frequency side to calculate a crest factor on the low frequency side; and determining whether the result of connector fitting work is good or bad on the basis of the crest factor on the high frequency side and the crest factor on the low frequency side.

Description

Inspection device

[0001] The present invention relates to an inspection device.

[0002] For example, Patent Document 1 discloses a connector fitting sound detection device that collects the fitting sound of a connector with a microphone and outputs it to an operator's earphone. In such Patent Document 1, among the output signals of the microphone, a high-frequency band signal near the connector fitting sound (15 kHz) is extracted, and the extracted signal is frequency-converted to a low-frequency band and output to the earphone. The operator can determine the quality of the connector fitting operation by listening to the sound output from the earphone.

[0003] Japanese Patent Application Laid-Open No. 2023-48915

[0004] In the technology of Patent Document 1, since the operator determines the quality of the connector fitting operation, subjective influences such as the operator's hearing ability and experience are reflected in the determination result, and the determination result may vary for each operator.

[0005] Therefore, an object of the present invention is to provide an inspection device capable of improving the accuracy of determining the quality in the connector fitting operation.

[0006] To solve the above problems, an inspection apparatus according to one embodiment of the present invention comprises: a sound sensor for acquiring sound signals; an AD converter for performing AD conversion on the sound signals acquired by the sound sensor; and an analysis apparatus for performing analysis on a first-time sound signal, which is the sound signal after AD conversion by the AD converter and includes the sound during the connector mating operation. The analysis apparatus comprises: one or more processors; and one or more memories connected to the processors. The processor performs harmonic percussion sound separation on the first-time sound signal after AD conversion, which is capable of separating the percussion sound from a sound that includes harmonic sounds, which are sounds that continue in time, and percussion sounds, which are instantaneous sounds, and acquires the sound signal of the percussion sound for the first time. It performs a short-time Fourier transform on the sound signal of the percussion sound for the first time using a preset window function to calculate the power density corresponding to the time and frequency in the first time. It calculates the crest factor on the high-frequency side by dividing the highest value of the power density on the high-frequency side, which is above a preset frequency threshold, by the effective value of the power density on the high-frequency side for the first time. The process includes: calculating the crest factor on the low-frequency side by dividing the highest value of the power density on the low-frequency side below the frequency threshold by the effective value of the power density on the low-frequency side for the first time; and determining whether the connector mating operation result is good or bad based on the crest factor on the high-frequency side and the crest factor on the low-frequency side.

[0007] According to the present invention, it is possible to improve the accuracy of determining whether a connector is good or bad during the mating process.

[0008] Figure 1 is a schematic diagram showing an example of the configuration of the inspection device according to this embodiment. Figure 2 is a diagram showing the characteristics of the mating sound of the connector according to this embodiment. Figure 3 is a flowchart showing the inspection flow by the inspection device according to this embodiment. Figure 4 is a diagram illustrating the first time point and the second time point according to this embodiment. Figure 5 is a conceptual diagram illustrating an example of a short-time Fourier transform according to this embodiment. Figure 6 is a diagram showing an example of a spectrogram representing the power density calculated by the short-time Fourier transform according to this embodiment. Figure 7 is a flowchart illustrating a first example of the mating determination process according to this embodiment. Figure 8 is a flowchart illustrating a second example of the mating determination process according to this embodiment. Figure 9 is a flowchart illustrating a third example of the mating determination process according to this embodiment.

[0009] Embodiments of the present invention will be described in detail below with reference to the attached drawings. The specific dimensions, materials, numerical values, etc., shown in these embodiments are merely examples to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustrations.

[0010] Figure 1 is a schematic diagram showing an example of the configuration of the inspection device 1 according to this embodiment. The inspection device 1 is used when an operator is performing the mating work on the connector 10, and determines whether the mating work result of the connector 10 is good or bad. The inspection device 1 determines whether the mating work result is good or bad by detecting the mating sound generated from the connector 10 when the connector 10 is mated.

[0011] Connector 10 is, for example, a harness connector mounted on a vehicle 12, but it is not limited to this example and may be any type of connector that generates noise when mated.

[0012] The connector 10 includes a plug 20 and a receptacle 22. The receptacle 22 is configured to accept the plug 20. The connector 10 is mated when the plug 20 is accepted into the receptacle 22.

[0013] The connector 10 includes a latch 24 representing a locking mechanism. For example, the plug 20 may be provided with a claw portion 26 as part of the latch 24. The receptacle 22 may be provided with a recess 28 that can accommodate the claw portion 26 as part of the latch 24. When the claw portion 26 is accommodated in the recess 28, the latch 24 functions and the plug 20 is locked against the receptacle 22. When the plug 20 is locked against the receptacle 22, the mating of the connector 10 is complete.

[0014] The connector 10 generates a mating sound, such as a click, at the moment the claw portion 26 is accommodated in the recessed portion 28, that is, at the moment the latch 24 functions. In other words, the connector 10 generates a mating sound when the mating is properly completed. Conversely, if the mating of the connector 10 is not properly completed, such as in a partial mating, the connector 10 does not generate a mating sound.

[0015] The inspection device 1 includes a sound sensor 40, a switch 42, a terminal device 44, and a notification device 46. The terminal device 44 includes an AD converter 50 and an analysis device 52.

[0016] The sound sensor 40 is, for example, a microphone. The sound sensor 40 may acquire sound signals at all times. The sound sensor 40 is capable of acquiring sound signals that substantially include sounds made during the mating operation of the connector 10. The sound sensor 40 may be attached, for example, to the wrist of the worker performing the mating operation of the connector 10.

[0017] The terminal device 44 may be, for example, an edge computer. The terminal device 44 may be connected to the sound sensor 40 by a wire. The terminal device 44 may be, for example, held by an operator, or installed in the location where the connector 10 is mated.

[0018] The AD converter 50 of the terminal device 44 performs AD conversion (analog-to-digital conversion) on the sound signal acquired by the sound sensor 40 each time an sound signal is acquired by the sound sensor 40.

[0019] The analysis device 52 of the terminal device 44 performs analysis on the first time period of the audio signal after AD conversion by the AD converter 50, which includes the sound during the mating operation of the connector 10. The first time period is, for example, 1 second, but is not limited to this example and may be set to various times considering the speed of the mating operation of the connector 10.

[0020] The analysis device 52 includes one or more processors 60 and one or more memories 62 connected to the processors 60. The memories 62 include ROM in which programs and the like are stored, and RAM as a work area. The memories 62 may also include storage in which programs and the like are stored. The processors 60 work in cooperation with the programs contained in the memories 62 to perform various processes.

[0021] For example, the processor 60 may function as an inspection processing unit 70 that determines whether the mating operation of the connector 10 is good or bad by executing a program. The inspection processing unit 70 will be described in detail later.

[0022] Memory 62 stores the sound signal acquired by the sound sensor 40 and after AD conversion by the AD converter 50, each time the sound sensor 40 acquires a sound signal. The terminal device 44 may include storage separate from memory 62. In that case, the sound signal may be stored in this storage separate from memory 62.

[0023] Switch 42 generates a predetermined trigger when it is turned on. Switch 42 may be, for example, a push button. Switch 42 is operated, for example, by an operator.

[0024] The analysis device 52 acquires an audio signal from the memory 62 at a time specified by the trigger, in response to a trigger by the switch 42. The processor 60 performs analysis on the audio signal read from the memory 62.

[0025] For example, after the operator turns on the switch 42, they immediately perform the mating operation of the connector 10. In this case, the sound generated by the mating operation of the connector 10 occurs after the trigger is generated by the switch 42. The analysis device 52 acquires the sound signal from the memory 62 for the first hour from the time the trigger occurred. In other words, the analysis device 52 can acquire the sound signal for the first hour from the time the trigger is generated by the switch 42 in virtually real time. As a result, the analysis device 52 can acquire the sound signal for the first hour, including the sound produced during the mating operation of the connector 10.

[0026] Alternatively, for example, the operator may turn on the switch 42 without delay after performing the mating operation of the connector 10. In this case, the trigger from the switch 42 will occur after the sound produced by the mating operation of the connector 10. In this case, the analysis device 52 may acquire from the memory 62 a sound signal from the first hour, which is based on a predetermined time prior to the time when the trigger occurred. In this embodiment as well, the analysis device 52 can acquire a sound signal from the first hour, which includes the sound produced during the mating operation of the connector 10.

[0027] Furthermore, the method is not limited to the operator turning on the switch 42. For example, the switch 42 may be automatically turned on at a predetermined timing, and the operator may perform the mating operation of the connector 10 in accordance with the switch 42 being turned on.

[0028] The notification device 46 is connected to the terminal device 44 by wire or wireless connection. The notification device 46 can receive the results determined by the inspection processing unit 70 from the terminal device 44 and notify the received results. For example, the notification device 46 may be a display device of a computer separate from the terminal device 44.

[0029] Furthermore, the notification device 46 is not limited to a display device; for example, it may be a sound output device capable of notifying the results by sound. Also, the notification device 46 is not limited to being provided separately from the terminal device 44; it may be included in the terminal device 44. In addition, the results determined by the inspection processing unit 70 may be stored in a computer such as a cloud server.

[0030] Figure 2 shows the characteristics of the mating sound of the connector 10 according to this embodiment. The mating sound of the connector 10 is an instantaneous impact sound like a click.

[0031] As shown in Figure 2, the amplitude of the mating sound of connector 10 increases and decreases in a short period of time. In other words, the vibration energy, i.e., the volume, of the mating sound of connector 10 increases and decreases in a short period of time.

[0032] Furthermore, as shown in Figure 2, the mating sound of connector 10 includes a wide range of frequencies, from relatively low to relatively high. More specifically, the mating sound of connector 10 includes not only audible frequencies but also inaudible frequencies higher than audible frequencies. Generally, sounds in the inaudible frequency range attenuate more with respect to propagation distance compared to sounds in the audible frequency range.

[0033] Figure 3 is a flowchart showing the inspection process using the inspection device 1 according to this embodiment. The operator turns on the switch 42, and immediately after turning on the switch 42, inserts the plug 20 into the receptacle 22 to perform the mating operation of the connector 10. The sound sensor 40 continuously acquires sound signals. The AD converter 50 performs AD conversion on the sound signal acquired by the sound sensor 40. The memory 62 stores the sound signal after AD conversion (S10).

[0034] The inspection processing unit 70 of the analysis device 52 acquires the sound signal from the memory 62 for the first hour from the time the trigger occurs, in response to the trigger generated by the ON operation of the switch 42 (S11).

[0035] The inspection processing unit 70 of the analysis device 52 performs harmonic percussion sound separation on the first time sound signal obtained from the memory 62 after AD conversion, and obtains a spectrogram of the first time percussion sound (S12).

[0036] Harmonic percussion separation is a process that can separate percussion sounds from sounds that contain harmonics, which are sounds that continue in time, and percussion sounds, which are instantaneous sounds. In a spectrogram obtained by performing a short-time Fourier transform on the original signal containing harmonics and percussion sounds, the power density of the harmonics spreads smoothly in the time direction. On the other hand, in the same spectrogram, the power density of the percussion sounds spreads smoothly in the frequency direction. Utilizing these characteristics, harmonic percussion separation can, for example, remove the harmonics that spread smoothly in the time direction and extract the percussion sounds that spread smoothly in the frequency direction by applying a median filter in the frequency direction to the spectrogram.

[0037] The inspection processing unit 70 obtains the sound signal of the percussion sound at the first time by performing an inverse Fourier transform on the spectrogram of the percussion sound at the first time that was separated by harmonic percussion sound separation (S13).

[0038] Next, the processes of steps S14 to S16 will be explained with reference to Figures 3 and 4. Figure 4 is a diagram illustrating the first time point and the second time point according to this embodiment.

[0039] After acquiring the sound signal of the percussion instrument sound during the first hour, the inspection processing unit 70 identifies a first time point in the sound signal of the percussion instrument sound during the first hour that represents the point in time when the amplitude exceeds a preset amplitude threshold (S14).

[0040] The double arrow A10 in Figure 4 indicates the first time period. Waveform A12 in Figure 4 shows an example of the sound signal of a percussion instrument at the first time period. The dashed line A20 in Figure 4 shows an example of an amplitude threshold. The amplitude threshold is set to a value that makes the loudness of the mating sound generated by the connector 10 distinguishable from the loudness of other noises. Since the amplitude at the first time point exceeds the amplitude threshold, the first time point can be considered a candidate for the time when the mating sound of the connector 10 occurred. The first time point is also the time in the first time period when the amplitude is at its maximum value.

[0041] After identifying the first time point, the inspection processing unit 70 identifies the second time point (S15). As shown by the double arrow A30 in Figure 4, the second time point is shorter than the first time point and includes the first time point.

[0042] For example, the second time is set as the time centered on the first time point. Note that the first time point at the second time is not limited to the central time point of the second time, and may be a predetermined regular time point included in the second time.

[0043] Further, the second time may be set in consideration of the fact that the amplitude of the fitting sound of the connector 10 decays in a short time (see FIG. 2). For example, the second time is a time when the amplitude of the fitting sound of the connector 10 is sufficiently attenuated, and may be set so that the time substantially not including the amplitude of the fitting sound of the connector 10 in the second time does not become excessively long.

[0044] After specifying the second time, the inspection processing unit 70 extracts the sound signal of the percussion instrument sound at the second time from the sound signal of the percussion instrument sound at the first time (S16). As will be described later, the extracted sound signal of the percussion instrument sound at the second time is used for calculating an index for determining the fitting operation result of the connector 10.

[0045] Next, the inspection processing unit 70 performs a short-time Fourier transform on the sound signal of the percussion instrument sound at the second time using a preset window function, and calculates the power density corresponding to the time and frequency at the second time (S17).

[0046] FIG. 5 is a conceptual diagram for explaining an example of the short-time Fourier transform according to the present embodiment. The area A40 in FIG. 5 conceptually shows a window function. The time width of the window function is shorter than the second time. As shown in FIG. 5, in step S17, the inspection processing unit 70 repeatedly multiplies the sound signal of the percussion instrument sound at the second time by the window function to perform Fourier transform while shifting the window function along the time axis by a predetermined shift amount.

[0047] When performing a short-time Fourier transform, the power density with respect to time and frequency is calculated for each frame (window). The inspection processing unit 70 can calculate the power density over the entire second time by performing the shift of the window function in the short-time Fourier transform over the entire second time.

[0048] FIG. 6 is a diagram showing an example of representing the power density calculated by the short-time Fourier transform according to the present embodiment by a spectrogram. As shown in FIG. 6, the horizontal axis represents time, and the vertical axis represents frequency. For convenience of explanation, in FIG. 6, the power density of the sound signal is represented by the fineness of the hatching. In the example of FIG. 6, as the hatching becomes finer, it means that the power density is higher. In fact, the power density in the spectrogram may be represented by color.

[0049] As shown in FIG. 6, in step S17, the power density is calculated over the entire second time and over a wide range of frequencies. Also, in the example of FIG. 6, the power density at the first time point is higher than the power densities before and after the first time point.

[0050] As shown in FIGS. 3 and 6, after calculating the power density, the inspection processing unit 70 divides the power density by frequency based on a preset frequency threshold value indicated by the dashed-dotted line A50 in FIG. 6 (S18). That is, the power density of the spectrogram shown in FIG. 6 is divided into a high-frequency side power density that is equal to or higher than the frequency threshold value and a low-frequency side power density that is less than the frequency threshold value.

[0051] The frequency threshold value may be set to a frequency (for example, 20 kHz, etc.) that divides the frequency into an audible frequency and an inaudible frequency. That is, the low-frequency side may be the audible range, and the high-frequency side may be the inaudible range.

[0052] Next, as shown in FIG. 3, the inspection processing unit 70 calculates a high-frequency side power density integrated value by integrating the high-frequency side power density at the first time point (S19).

[0053] The inspection processing unit 70 calculates a low-frequency side power density integrated value by integrating the low-frequency side power density at the first time point (S20)

[0054] The inspection processing unit 70 calculates a wide-area power density integrated value by integrating both the high-frequency side and low-frequency side power densities at the first time point (S21)

[0055] The inspection processing unit 70 calculates the high-frequency energy ratio, which represents the ratio of the high-frequency power density integrated value to the wide-area power density integrated value, by dividing the high-frequency power density integrated value by the wide-area power density integrated value (S22).

[0056] The inspection processing unit 70 calculates the low-frequency energy ratio, which represents the ratio of the low-frequency power density integrated value to the wide-area power density integrated value, by dividing the low-frequency power density integrated value by the wide-area power density integrated value (S23).

[0057] Next, the inspection processing unit 70 calculates the crest factor on the high-frequency side by dividing the highest value of the power density on the high-frequency side at the second time by the effective value of the power density on the high-frequency side at the second time (S24). The crest factor on the high-frequency side represents how instantaneous the sound on the high-frequency side at the first time point is.

[0058] The inspection processing unit 70 calculates the crest factor on the low-frequency side by dividing the maximum value of the power density at the second time on the low-frequency side by the effective value of the power density at the second time on the low-frequency side (S25). The crest factor on the low-frequency side represents how instantaneous the sound on the low-frequency side at the first time point is.

[0059] Next, the inspection processing unit 70 performs a mating determination process (S30) to determine whether the mating operation of the connector 10 is good or bad. The flow of the mating determination process (S30) will be described later.

[0060] The inspection processing unit 70 outputs the result of the fitting determination process (S30) to the notification device 46 (S31). As a result, the notification device 46 notifies the determination result. The operator can recognize the determination result through the notification device 46. For example, the notification device 46 may notify in both cases: when the fitting result is determined to be good, and when the fitting result is determined to be poor. Alternatively, the notification device 46 may notify only when the fitting result is determined to be good.

[0061] Three examples of the fitting determination process (S30) can be given. The first example of the fitting determination process (S30) will be explained below with reference to Figure 7, the second example of the fitting determination process (S30) will be explained with reference to Figure 8, and the third example of the fitting determination process (S30) will be explained with reference to Figure 9.

[0062] Figure 7 is a flowchart illustrating a first example of the fitting determination process (S30) according to this embodiment. As shown in Figure 7, the inspection processing unit 70 determines whether the crest ratio on the high-frequency side is greater than the first threshold (S40).

[0063] The first threshold may be set according to the level of noise in the surrounding environment during the mating operation of the connector 10. For example, if the level of noise in the surrounding environment is relatively high, the first threshold may be set to a relatively high value.

[0064] If the crest factor on the high-frequency side is determined to be greater than the first threshold (YES in S40), the inspection processing unit 70 determines whether the crest factor on the low-frequency side is greater than the second threshold (S41).

[0065] The second threshold may be set according to the level of noise in the surrounding environment during the mating operation of the connector 10. For example, if the level of noise in the surrounding environment is relatively high, the second threshold may be set to a relatively high value.

[0066] If the low-frequency crest ratio is determined to be greater than the second threshold (YES in S41), the inspection processing unit 70 determines that the mating operation of the connector 10 is good (S50) and terminates the mating determination process (S30).

[0067] As described above, the mating sound of connector 10 includes a wide range of frequencies, from relatively low to relatively high. Therefore, when the mating sound of connector 10 occurs near the sound sensor 40, the sound signal acquired by the sound sensor 40 includes instantaneous sounds of a wide range of frequencies, which are the mating sound of connector 10.

[0068] However, as mentioned above, relatively high-frequency sounds attenuate more with respect to propagation distance than relatively low-frequency sounds. Therefore, if an impact sound occurs far from the sound sensor 40, the relatively high-frequency sounds contained in the impact sound will attenuate before they propagate towards the sound sensor 40. Consequently, even if the sound sensor 40 acquires vibrations from an impact sound at a distance, the power density on the high-frequency side of the impact sound acquired by the sound sensor 40 will be low.

[0069] Based on these factors, the inspection processing unit 70 can infer that an audible instantaneous impact sound occurred because the crest ratio on the low-frequency side is greater than the second threshold. The inspection processing unit 70 can infer that an instantaneous impact sound occurred near the sound sensor 40 because the crest ratio on the high-frequency side is greater than the first threshold. Therefore, the inspection processing unit 70 can infer that an audible instantaneous impact sound occurred near the sound sensor 40, that is, the mating sound of the connector 10 occurred, when the crest ratio on the high-frequency side is greater than the first threshold and the crest ratio on the low-frequency side is greater than the second threshold. Since it is inferred that the mating sound of the connector 10 occurred, the inspection processing unit 70 can determine that the mating result of the connector 10 is good.

[0070] In contrast, if the crest factor on the high-frequency side is determined to be below the first threshold (NO in S40), or if the crest factor on the low-frequency side is determined to be below the second threshold (NO in S41), the inspection processing unit 70 determines that the mating result of the connector 10 is not good (S51), and terminates the mating determination process (S30).

[0071] For example, if the crest ratio on the low-frequency side is below the second threshold, it is inferred that the audible sound at the first time point is not instantaneous enough to be considered the mating sound of the connector 10. Therefore, if the crest ratio on the low-frequency side is below the second threshold, it is inferred that no mating sound of the connector 10 has occurred, and the inspection processing unit 70 can determine that the mating result of the connector 10 is not good.

[0072] Furthermore, for example, if the crest ratio on the high-frequency side is below the first threshold, it is inferred that the sound at the first time point does not contain high-frequency sounds that can be considered instantaneous. Therefore, if the crest ratio on the high-frequency side is below the first threshold, it is inferred that no instantaneous impact sound occurred near the sound sensor 40, and the inspection processing unit 70 can determine that the mating result of the connector 10 is not good.

[0073] Thus, in the inspection device 1 of this embodiment, the quality of the mating operation of the connector 10 is determined based on the crest factor on the high frequency side and the crest factor on the low frequency side.

[0074] As a result, the inspection device 1 of this embodiment can eliminate the operator's subjectivity in determining whether the connector 10 is properly fitted, thereby improving the accuracy of determining whether the connector 10 is properly fitted.

[0075] Furthermore, when performing the mating determination process (S30) of the first example shown in Figure 7, the calculation of the integrated power density on the high frequency side (S19), the calculation of the integrated power density on the low frequency side (S20), the calculation of the integrated power density over a wide area (S21), the calculation of the high frequency side energy ratio (S22), and the calculation of the low frequency side energy ratio (S23) in Figure 3 may be omitted.

[0076] Figure 8 is a flowchart illustrating a second example of the fitting determination process (S30) according to this embodiment. As shown in Figure 8, the second example has step S60 added to the first example. For the sake of explanation, the differences between the second example and the first example will be explained, and the same points as the first example will be omitted from the explanation.

[0077] In the second example, if it is determined that the crest ratio on the high frequency side is greater than the first threshold (YES in S40), and that the crest ratio on the low frequency side is greater than the second threshold (YES in S41), the inspection processing unit 70 determines whether the high frequency side energy ratio is greater than the third threshold (S60).

[0078] The third threshold may be set according to the level of noise in the surrounding environment during the mating operation of the connector 10. For example, if the level of noise in the surrounding environment is relatively high, the third threshold may be set to a relatively high value.

[0079] If the high-frequency energy ratio is determined to be greater than the third threshold (YES in S60), the inspection processing unit 70 determines that the mating operation result of the connector 10 is good (S50) and terminates the mating determination process (S30).

[0080] A high-frequency energy ratio greater than the third threshold means that a large portion of the power density at the first time point is on the high-frequency side compared to the total power density at all frequencies. In other words, in this case, it can be inferred that the sound at the first time point was an impact sound generated near the sound sensor 40. Therefore, in addition to the crest factor condition, when the high-frequency energy ratio is greater than the third threshold, the probability that the mating sound of the connector 10 was generated near the sound sensor 40 increases, and the inspection processing unit 70 can determine that the mating result of the connector 10 is good.

[0081] In contrast, if the crest ratio on the high-frequency side is determined to be below the first threshold (NO in S40), if the crest ratio on the low-frequency side is determined to be below the second threshold (NO in S41), or if the energy ratio on the high-frequency side is determined to be below the third threshold (NO in S60), the inspection processing unit 70 determines that the mating result of the connector 10 is not good (S51), and terminates the mating determination process (S30).

[0082] For example, if the high-frequency energy ratio is below the third threshold, it is inferred that the sound at the first time point does not contain sufficient high-frequency power density. Therefore, if the high-frequency energy ratio is below the third threshold, it is inferred that the sound at the first time point originated far from the sound sensor 40, and the inspection processing unit 70 can determine that the mating result of the connector 10 is not good.

[0083] Thus, in the inspection device 1 of this embodiment, the quality of the mating operation result of the connector 10 may be determined based on the crest factor on the high frequency side, the crest factor on the low frequency side, and the energy ratio on the high frequency side.

[0084] As a result, the mating determination process (S30) in the second example of Figure 8 can be made more accurate in determining whether the connector 10 is mated compared to the mating determination process (S30) in the first example of Figure 7.

[0085] Furthermore, when performing the mating determination process (S30) of the second example shown in Figure 8, the calculation of the integrated power density on the low-frequency side (S20) and the calculation of the low-frequency side energy ratio (S23) in Figure 3 may be omitted.

[0086] Figure 9 is a flowchart illustrating a third example of the fitting determination process (S30) according to this embodiment. As shown in Figure 9, the third example is the first example with the addition of step S70. For the sake of explanation, the differences between the third example and the first example will be explained, and the same points as the first example will be omitted from the explanation.

[0087] In the third example, if it is determined that the crest ratio on the high-frequency side is greater than the first threshold (YES in S40), and that the crest ratio on the low-frequency side is greater than the second threshold (YES in S41), the inspection processing unit 70 determines whether or not the low-frequency energy ratio is less than the fourth threshold (S70).

[0088] The fourth threshold may be set according to the level of noise in the surrounding environment during the mating operation of the connector 10. For example, if the level of noise in the surrounding environment is relatively high, the fourth threshold may be set to a relatively high value. Alternatively, the fourth threshold may be the value obtained by subtracting the third threshold in step S60 of Figure 8 from 1 (fourth threshold = 1 - third threshold).

[0089] If the low-frequency energy ratio is determined to be less than the fourth threshold (YES in S70), the inspection processing unit 70 determines that the mating operation of the connector 10 is good (S50) and terminates the mating determination process (S30).

[0090] A low-frequency energy ratio below the fourth threshold suggests that, relative to the total power density at the first time point, the high-frequency power density is higher, resulting in a relatively lower low-frequency power density. In other words, in this case, the sound at the first time point is presumed to be an impact sound generated near the sound sensor 40. Therefore, in addition to the crest factor condition, when the low-frequency energy ratio is below the fourth threshold, the probability that the mating sound of the connector 10 occurred near the sound sensor 40 increases, and the inspection processing unit 70 can determine that the mating result of the connector 10 is good.

[0091] In contrast, if the high-frequency crest ratio is determined to be below the first threshold (NO in S40), if the low-frequency crest ratio is determined to be below the second threshold (NO in S41), or if the low-frequency energy ratio is determined to be above the fourth threshold (NO in S70), the inspection processing unit 70 determines that the mating result of the connector 10 is not good (S51), and terminates the mating determination process (S30).

[0092] For example, if the low-frequency energy ratio is above the fourth threshold, it is inferred that the sound at the first time point does not contain sufficient high-frequency power density, and therefore contains an excessive amount of low-frequency power density. For this reason, if the low-frequency energy ratio is above the fourth threshold, it is inferred that the sound at the first time point originated far from the sound sensor 40, and the inspection processing unit 70 can determine that the mating result of the connector 10 is not good.

[0093] Thus, in the inspection device 1 of this embodiment, the quality of the mating operation result of the connector 10 may be determined based on the crest factor on the high frequency side, the crest factor on the low frequency side, and the energy ratio on the low frequency side.

[0094] As a result, the mating determination process (S30) in the third example of Figure 9 can be made more accurate in determining whether the connector 10 is mated compared to the mating determination process (S30) in the first example of Figure 7.

[0095] Furthermore, when performing the fitting determination process (S30) of the third example shown in Figure 9, the calculation of the integrated power density value on the high frequency side (S19) and the calculation of the high frequency side energy ratio (S22) in Figure 3 may be omitted.

[0096] Furthermore, a mating determination process (S30) combining the second example shown in Figure 8 and the third example shown in Figure 9 may be performed. For example, the inspection processing unit 70 may determine that the mating result of the connector 10 is good if it determines that the crest ratio on the high frequency side is greater than the first threshold, the crest ratio on the low frequency side is greater than the second threshold, the energy ratio on the high frequency side is greater than the third threshold, and the energy ratio on the low frequency side is less than the fourth threshold. In this embodiment as well, it is possible to further improve the accuracy of the good or bad determination in the mating operation of the connector 10.

[0097] Furthermore, in the inspection device 1 of this embodiment, the sound signal of the percussion instrument sound at the second time is extracted from the sound signal of the percussion instrument sound at the first time, and the sound signal of the percussion instrument sound at the second time is used to calculate an index for determining the mating result of the connector 10. As a result, the inspection device 1 of this embodiment can reduce the processing load for calculating the index for determining the mating result of the connector 10.

[0098] Furthermore, the method is not limited to extracting the sound signal of the percussion instrument sound from the sound signal of the percussion instrument sound from the first time. For example, the sound signal of the percussion instrument sound from the first time may be used to calculate an index for determining the mating result of the connector 10. In this case, specifying the second time (S15) and extracting the sound signal of the percussion instrument sound from the second time (S16) may be omitted.

[0099] For example, in step S17 of Figure 3, the inspection processing unit 70 may perform a short-time Fourier transform on the sound signal of the percussion instrument at the first time using a preset window function to calculate the power density corresponding to the time and frequency at the first time. In step S24, the inspection processing unit 70 may calculate the crest factor on the high-frequency side by dividing the maximum value of the power density at the first time on the high-frequency side by the effective value of the power density at the first time on the high-frequency side. In step S25, the inspection processing unit 70 may calculate the crest factor on the low-frequency side by dividing the maximum value of the power density at the first time on the low-frequency side by the effective value of the power density at the first time on the low-frequency side. The inspection processing unit 70 may then determine whether the mating operation result of the connector 10 is good or bad based on the crest factor on the high-frequency side and the crest factor on the low-frequency side.

[0100] In the inspection device 1 of this embodiment, even if the extraction of the sound signal of the percussion instrument sound at the second time is omitted, the quality of the mating operation of the connector 10 is determined based on the crest factor on the high frequency side and the crest factor on the low frequency side. Therefore, even if the extraction of the sound signal of the percussion instrument sound at the second time is omitted in the inspection device 1 of this embodiment, it is possible to improve the accuracy of the quality determination in the mating operation of the connector 10. However, the method of extracting the sound signal of the percussion instrument sound at the second time is more preferable because it can improve the accuracy of mating determination in the actual work environment and reduce the processing load.

[0101] Embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these embodiments. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention.

[0102] Furthermore, the processes described herein do not necessarily have to be performed chronologically in the order shown in the flowchart; they may include parallel processing or processing by subroutines.

[0103] 1 Inspection device 10 Connectors 40 Sound sensors 50 AD converters 52 Analysis device 60 Processors 62 Memory 70 Inspection processing unit

Claims

1. A sound sensor for acquiring sound signals; an AD converter for performing AD conversion on the sound signals acquired by the sound sensor; and an analysis device for performing analysis on the sound signal after AD conversion by the AD converter, which includes the sound of the connector mating operation during the first time period, wherein the analysis device comprises one or more processors and one or more memories connected to the processors, wherein the processor performs harmonic percussion sound separation on the sound signal after AD conversion of the first time period, which includes harmonic sounds that are continuous in time and percussion sounds that are instantaneous sounds, to separate the percussion sounds from the sound, and acquires the sound signal of the percussion sounds during the first time period; performs a short-time Fourier transform on the sound signal of the percussion sounds during the first time period using a preset window function to calculate the power density corresponding to the time and frequency in the first time period; and calculates the crest factor on the high-frequency side by dividing the highest value of the power density on the high-frequency side above a preset frequency threshold by the effective value of the power density on the high-frequency side during the first time period, An inspection device that performs a process including: calculating the crest factor on the low-frequency side by dividing the highest value of the power density on the low-frequency side below the frequency threshold by the effective value of the power density on the low-frequency side for the first time; and determining whether the mating operation result of the connector is good or bad based on the crest factor on the high-frequency side and the crest factor on the low-frequency side.

2. The inspection apparatus according to claim 1, wherein the processor performs a process that includes: determining that the result of the connector mating operation is good when the crest ratio on the high frequency side is greater than a preset first threshold and the crest ratio on the low frequency side is greater than a preset second threshold; and determining that the result of the connector mating operation is not good when at least one of the following is true: the crest ratio on the high frequency side is less than or equal to the first threshold and the crest ratio on the low frequency side is less than or equal to the second threshold.

3. The inspection apparatus according to claim 1, wherein the low-frequency side is in the audible range and the high-frequency side is in the inaudible range.

4. The processor performs the following processes after acquiring the sound signal of the percussion instrument sound for the first time, identifying a first time point in the sound signal of the percussion instrument sound for the first time that represents the time when the amplitude exceeds a preset amplitude threshold, identifying a second time period that is shorter than the first time period and includes the first time point, and extracting the sound signal of the percussion instrument sound for the second time from the sound signal of the percussion instrument sound for the first time. The power density is calculated in the second time period by performing the short-time Fourier transform on the sound signal of the percussion instrument sound for the second time period. The crest ratio on the high frequency side is calculated by dividing the highest value of the power density on the high frequency side by the effective value of the power density for the second time period on the high frequency side. The crest ratio on the low frequency side is calculated by dividing the highest value of the power density on the low frequency side by the effective value of the power density for the second time period on the low frequency side. The quality of the connector mating operation is determined based on the crest ratio on the high frequency side and the crest ratio on the low frequency side. The inspection apparatus according to claim 1.

5. The inspection apparatus according to claim 1, wherein the processor, after acquiring the sound signal of the percussion instrument sound for the first time, identifies a first time point in the sound signal of the percussion instrument sound for the first time that represents the time when the amplitude exceeds a preset amplitude threshold; calculates the integrated power density value on the high frequency side by integrating the power density on the high frequency side at the first time point; calculates the integrated power density value over a wide area by integrating the power densities on both the high frequency side and the low frequency side at the first time point; and calculates the high frequency side energy ratio that represents the ratio of the integrated power density value on the high frequency side to the integrated power density value over the wide area, and determines whether the result of the connector mating operation is good or bad based on the crest factor on the high frequency side, the crest factor on the low frequency side and the high frequency side energy ratio.

6. The inspection apparatus according to claim 5, wherein the processor performs a process that includes: determining that the result of the connector mating operation is good when the crest ratio on the high frequency side is greater than a preset first threshold, the crest ratio on the low frequency side is greater than a preset second threshold, and the high frequency side energy ratio is greater than a preset third threshold; and determining that the result of the connector mating operation is not good when at least one of the following is true: the crest ratio on the high frequency side is less than or equal to the first threshold, the crest ratio on the low frequency side is less than or equal to the second threshold, and the high frequency side energy ratio is less than or equal to the third threshold.

7. The inspection apparatus according to claim 1, wherein the processor performs the following processes: after acquiring the sound signal of the percussion instrument sound for the first time, it identifies a first time point in the sound signal of the percussion instrument sound for the first time that represents the time when the amplitude exceeds a preset amplitude threshold; calculates the integrated power density value on the low frequency side by integrating the power density on the low frequency side at the first time point; calculates the integrated power density value over a wide area by integrating the power densities on both the high frequency side and the low frequency side at the first time point; and calculates the low frequency side energy ratio that represents the ratio of the integrated power density value on the low frequency side to the integrated power density value over a wide area, and the quality of the connector mating operation is determined based on the crest factor on the high frequency side, the crest factor on the low frequency side, and the low frequency side energy ratio.

8. The inspection apparatus according to claim 7, wherein the processor performs a process that includes: determining that the result of the connector mating operation is good when the crest ratio on the high frequency side is greater than a preset first threshold, the crest ratio on the low frequency side is greater than a preset second threshold, and the energy ratio on the low frequency side is less than a preset fourth threshold; and determining that the result of the connector mating operation is not good when at least one of the following is true: the crest ratio on the high frequency side is less than or equal to the first threshold, the crest ratio on the low frequency side is less than or equal to the second threshold, and the energy ratio on the low frequency side is less than the fourth threshold.

Images