Vehicle speed acquisition device and abnormal noise diagnostic system

Abstract

To provide a vehicle speed acquisition device capable of acquiring useful vehicle speed data from vehicle position information and data of sounds generated by the vehicle.SOLUTION: A disclosed vehicle speed acquisition device acquires positional information at a first predefined time interval and sound pressure emitted from the vehicle during a second time interval, which is shorter than the first time interval. Based on the acquired position information and first and second-time intervals, the vehicle speed at the time of acquiring position information and the vehicle speed at the time of acquiring the sound pressure are estimated. The accuracy of the vehicle speed estimation is acquired based on the rate of change in vehicle speed between times when position information was acquired and the rate of change in sound pressure between acquisition times. The acquired estimation accuracy is associated with the vehicle speed at the time when the estimated sound pressure is acquired.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a vehicle speed acquisition device that acquires the vehicle speed of a vehicle based on the position information of the vehicle, and a abnormal sound diagnosis system including the same.

Background Art

[0002] Conventionally, a navigation device that detects the vehicle speed of a vehicle based on the reception result of radio waves from GPS satellites is known (see, for example, Patent Document 1). This navigation device performs sound collection at a predetermined position in the vehicle, acquires the inclination angle of the traveling route of the vehicle, and extracts, for each inclination angle, characteristic information of the sound collection result corresponding to the vehicle speed based on the vehicle speed detection result and the sound collection result. Further, the navigation device classifies and stores, for each inclination angle, sound collection characteristic information associating the vehicle speed and the characteristic information, and when it is not possible to receive radio waves from the required number of GPS satellites necessary for detecting the vehicle speed, estimates the vehicle speed in consideration of the sound collection result, the inclination angle of the traveling route, and the sound collection characteristic information.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above conventional navigation device, when the extracted characteristic information of the sound collection result or the acquired inclination angle is not included in the sound collection characteristic information, the vehicle speed cannot be estimated. In addition, the processing burden of extracting the characteristic information of the sound collection result and generating / classifying the sound collection characteristic information is not necessarily light, and moreover, the data volume of the sound collection characteristic information increases with the use time of the vehicle.

[0005] Therefore, the main object of the present disclosure is to enable acquisition of useful vehicle speed data from the position information of a vehicle and the data of the sound generated by the vehicle. [Means for solving the problem]

[0006] The vehicle speed acquisition device of this disclosure is a vehicle speed acquisition device that acquires the vehicle speed of a vehicle based on the vehicle's position information, comprising: a position information acquisition unit that acquires the position information at a predetermined first time interval; a sound pressure acquisition unit that acquires the sound pressure of sounds emitted from the vehicle at a second time interval shorter than the first time interval; a vehicle speed estimation unit that estimates the vehicle speed at the timing of acquisition of the position information and the vehicle speed at the timing of acquisition of the sound pressure based on the position information acquired by the position information acquisition unit and the first and second time intervals; and the vehicle speed estimation unit that estimates the timing of acquisition of the position information at the timing of acquisition of the position information. The system includes: a vehicle speed change rate acquisition unit that acquires the rate of change of the vehicle speed between the timings for acquiring the position information based on the vehicle speed and the first time interval; a sound pressure change rate acquisition unit that acquires the rate of change of the sound pressure between the timings for acquiring the sound pressure based on the sound pressure acquired by the sound pressure acquisition unit and the second time interval; and an estimation accuracy acquisition unit that acquires the estimation accuracy of the vehicle speed by the vehicle speed estimation unit based on the rate of change of the vehicle speed and the rate of change of the sound pressure, and links the acquired estimation accuracy to the vehicle speed at the timing for acquiring the sound pressure estimated by the vehicle speed estimation unit.

[0007] The abnormal noise diagnostic system of this disclosure is an abnormal noise diagnostic system including the above-mentioned vehicle speed acquisition device, which is capable of acquiring location information and sound data emitted from the vehicle, and includes a mobile terminal including the vehicle speed acquisition device, and a diagnostic device constructed by machine learning to diagnose abnormal noises generated in the vehicle based on the sound data transmitted from the mobile terminal and the vehicle speed acquired by the vehicle speed acquisition device, wherein the diagnostic device selects the vehicle speed to be used for diagnosing the abnormal noise based on the estimation accuracy linked to the vehicle speed from the mobile terminal. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram illustrating the abnormal sound diagnosis system disclosed herein. [Figure 2] This is a flowchart illustrating the abnormal noise diagnosis procedure using the abnormal noise diagnosis system described herein. [Figure 3] This is a flowchart illustrating the procedure for acquiring the vehicle speed using a mobile terminal that constitutes the abnormal noise diagnosis system of this disclosure. [Figure 4] This is a time chart illustrating the procedure for acquiring vehicle speed using a mobile terminal that constitutes the abnormal noise diagnostic system of this disclosure. [Figure 5] This is a flowchart illustrating the procedure for deriving the accuracy of vehicle speed estimation using a mobile terminal that constitutes the abnormal noise diagnosis system of this disclosure. [Modes for carrying out the invention]

[0009] Next, with reference to the drawings, embodiments for carrying out the invention of this disclosure will be described.

[0010] Figure 1 is a schematic diagram showing the abnormal noise diagnosis system 1 of this disclosure. The abnormal noise diagnosis system 1 shown in the figure is for diagnosing the cause of abnormal noises occurring in vehicles 100 such as vehicles equipped only with an engine as a power source, hybrid vehicles (HEV, PHEV), and electric vehicles (BEV, FCEV), and includes a mobile terminal 10 and a server 20 that can exchange information with the mobile terminal 10 via communication.

[0011] The mobile terminal 10 is used by workers at vehicle dealerships, repair shops, etc. (users of the abnormal noise diagnosis system 1) to respond to the user (owner) of the vehicle 100 that has produced an abnormal noise, and to conduct reproduction tests to reproduce the abnormal noise by driving (operating) the vehicle 100 on a roadway or test bench. In this embodiment, the mobile terminal 10 is a so-called smartphone and includes an SoC, ROM, RAM, GPS module (location information acquisition unit) G, auxiliary storage device (flash memory) M, touch panel display unit 11, communication module 12 capable of exchanging various information with the server 20 and the electronic control device of the vehicle 100 via wired or wireless communication, a microphone (not shown), etc. In addition, an abnormal noise diagnosis support application (program) is installed on the mobile terminal 10. As shown in Figure 1, the mobile terminal 10 includes a medical interview information acquisition unit 13, a sound acquisition unit 14, a vehicle status acquisition unit 15, a calculation processing unit 16, an extraction unit 17, and a display control unit 18, which are constructed through the collaboration of an abnormal sound diagnosis support application (software) and hardware such as the SoC of the mobile terminal 10.

[0012] The medical information acquisition unit 13 acquires information indicating the state of the vehicle 100 at the time of abnormal noise occurrence (hereinafter referred to as "medical information") provided by the user of the vehicle 100 via the display unit 11. The medical information includes vehicle identification information including the vehicle identification number (chassis number), requested information, date and time of occurrence, frequency of occurrence, location of abnormal noise, type of sound (onomatopoeia), physical quantities that change when the vehicle 100 is running such as vehicle speed, the driving state of the vehicle 100, the warm-up effect in vehicles equipped with an engine, selection items selected by the driver while the vehicle 100 is running, and information on the driving environment of the vehicle 100, and is input by the operator or the user of the vehicle 100. The sound acquisition unit 14 acquires time-axis data of the sound via a microphone when a reproduction test is performed by the operator.

[0013] The vehicle status acquisition unit 15 acquires information indicating the state of the vehicle 100 (hereinafter referred to as "vehicle status data") in synchronization with the acquisition of time-axis sound data by the sound acquisition unit 14 when a reproduction test is performed, and also performs processing on the acquired vehicle status data. The vehicle status data includes multiple physical quantities such as vehicle speed V and engine speed Ne, which correspond to items in the medical questionnaire information. In this embodiment, the vehicle status acquisition unit 15 acquires vehicle status data from the electronic control unit of the vehicle 100 to which the mobile terminal 10 is connected via a cable or the like. The vehicle status acquisition unit 15 can also acquire location information from the GPS module G and acquire the vehicle speed V of the vehicle 100 based on the acquired location information. The calculation processing unit 16 performs analysis processing of the time-axis sound data acquired by the sound acquisition unit 14. The extraction unit 17 performs filtering of the analysis results by the calculation processing unit 16 according to the operator's selection, etc. The display control unit 18 controls the display unit 11.

[0014] The server 20 of the abnormal noise diagnosis system 1 is a computer (information processing device) including a CPU, ROM, RAM, input / output devices, communication modules, etc., and is installed and managed by, for example, the automobile manufacturer that manufactures the vehicle 100. The server 20 has an abnormal noise diagnosis unit 21 built as a diagnostic device that diagnoses abnormal noises generated in the vehicle 100 through the cooperation of hardware such as the CPU and a pre-installed abnormal noise diagnosis application. The abnormal noise diagnosis unit 21 includes a neural network (convolutional neural network) built by supervised learning (machine learning) to diagnose the cause of abnormal noises generated in the vehicle 100 and the parts that are the source of the abnormal noises, based on questionnaire information, sound time axis data, vehicle condition data, etc. acquired by the mobile terminal 10. Furthermore, if the server 20 detects the occurrence of a new abnormal noise in the vehicle 100, it performs retraining of the abnormal noise diagnosis unit 21 using the sound time axis data acquired for the new abnormal noise and the contents of each item of the questionnaire information as training data.

[0015] Furthermore, the server 20 includes a storage device 22 that stores a database containing information about multiple abnormal noises known to occur in each vehicle model. The database stores information such as the time axis data of the sound, the cause of the abnormal noise, the source part, the content of the medical information provided by the user, etc., and measures to eliminate the abnormal noise, linked to each of the multiple abnormal noises. The server 20 also updates the database based on information obtained from a large number of vehicles, including vehicle 100, and information on newly discovered abnormal noises transmitted from automobile manufacturers (developers, etc.), vehicle dealerships, repair shops, etc.

[0016] Next, with reference to Figure 2, the procedure for diagnosing abnormal noises using the abnormal noise diagnosis system 1 will be explained. When a worker at a vehicle dealership or repair shop receives a request from a user of vehicle 100 to eliminate an abnormal noise, they gather information from the user and then conduct a reproduction test to obtain the information necessary for diagnosing the abnormal noise. When conducting the reproduction test, the worker either connects the mobile terminal 10 to the electronic control unit of vehicle 100, or places or fixes the mobile terminal 10 or an external microphone connected to the mobile terminal 10 in an appropriate location on vehicle 100 without connecting the mobile terminal 10 to the electronic control unit of vehicle 100. The worker also starts the abnormal noise diagnosis support application and turns on the start switch of vehicle 100. As a result, the mobile terminal 10 obtains information such as the vehicle identification number or chassis number of vehicle 100 from the electronic control unit. Furthermore, the operator taps the recording start button displayed on the display unit 11 and drives (operates) the vehicle 100 on the roadway or test stand, reproducing the driving conditions in which the abnormal noise occurred based on the information gathered from the vehicle 100's user.

[0017] While the vehicle 100 is in motion (operating), the sound acquisition unit 14 of the mobile terminal 10 acquires time-axis data of sounds emitted from the vehicle 100 and stores it in the auxiliary storage device M. In addition, the vehicle status acquisition unit 15 acquires vehicle status data specified by the worker according to the medical interview information from the electronic control device of the vehicle 100 in synchronization with the acquisition of time-axis data of sounds by the sound acquisition unit 14, and stores it in the auxiliary storage device M. Furthermore, if the mobile terminal 10 is not connected to the electronic control device of the vehicle 100, the GPS module G acquires the location information (self-position information) of the vehicle 100 at a predetermined first time interval Tp (for example, about 0.5-1 seconds), and the acquired location information is stored in the auxiliary storage device M. When the worker taps the recording stop button displayed on the display unit 11, the acquisition of time-axis data of sounds, vehicle status data, etc. is completed, and the mobile terminal 10 executes the series of processes shown in Figure 2. Furthermore, if the mobile terminal 10 is not connected to the electronic control unit of the vehicle 100, the vehicle status acquisition unit 15 of the mobile terminal 10 acquires (estimates) the vehicle speed V of the vehicle 100 based on the location information acquired by the GPS module G after the recording stop button is tapped and before the process shown in Figure 2 begins.

[0018] As shown in Figure 2, after the reproduction test is completed, the arithmetic processing unit 16 of the mobile terminal 10 acquires the time-axis data of the sound acquired by the sound acquisition unit 14 (step S100), and applies STFT (Short-Time Fourier Transform) to the acquired time-axis data of the sound to obtain a spectrogram (acoustic spectrogram) that shows the relationship between time, frequency, and sound pressure (step S110). The display control unit 18 of the mobile terminal 10 displays the spectrogram acquired by the arithmetic processing unit 16 on the display unit 11 (step S120). The spectrogram is a color map that shows the relationship between time and sound pressure level for each frequency by using the horizontal axis as the time axis and the vertical axis as the frequency axis, and color-coding the sound pressure level.

[0019] When a spectrogram is displayed on the display unit 11 of the mobile terminal 10, an operator selects (designates) a range (hereinafter referred to as "diagnostic range") to be diagnosed (analyzed) by the abnormal sound diagnosis unit 21 (server 20) among the spectrograms on the display unit 11. In response to the operator's screen operation, the extraction unit 17 acquires the diagnostic range selected by the operator and gives an instruction to the display control unit 18 to display the diagnostic range on the display unit 11 (step S130). Further, the extraction unit 17 reads out vehicle state data (including the vehicle speed V acquired based on the position information) within the diagnostic range (step S140), and extracts information to be provided to the server 20 as interrogation information from the read vehicle state data (step S150).

[0020] After the processing of step S150, the display control unit 18 causes the display unit 11 to display a message instructing the input of interrogation information. After the operator completes the input of interrogation information, the interrogation information acquisition unit 13 determines the information extracted in step S150 and the information input by the operator as the final interrogation information (step S160). When the interrogation information is determined and the operator taps the information transmission button displayed on the display unit 11, information necessary for diagnosing abnormal sounds is transmitted from the communication module 12 of the mobile terminal 10 to the server 20 (step S170). In the present embodiment, the information transmitted from the mobile terminal 10 to the server 20 includes at least the time-axis data of the sound, the interrogation information, the vehicle state data, and information defining the diagnostic range selected by the operator.

[0021] When information necessary for diagnosing abnormal noises is transmitted from the mobile terminal 10 to the server 20, the abnormal noise diagnosis unit 21 of the server 20 diagnoses the cause of the abnormal noise generated in the vehicle 100 based on the information provided from the mobile terminal 10, and transmits the diagnosis result to the mobile terminal 10. The diagnosis result includes the cause of the abnormal noise generated in the vehicle 100, the parts that are the sources of the abnormal noise, and countermeasures for eliminating the abnormal noise read from the storage device 22. Then, when the diagnosis result from the server 20 is received by the mobile terminal 10 (step S180), the diagnosis result is displayed on the display unit 11 (step S190), and a series of processes executed by the mobile terminal 10 during the diagnosis of the abnormal noise ends. By executing the process shown in FIG. 2, the operator can accurately explain the diagnosis result from the server 20 to the user of the vehicle 100 or the like and promptly proceed with countermeasures against the abnormal noise.

[0022] FIG. 3 is a flowchart showing a routine executed by the vehicle state acquisition unit 15 of the mobile terminal 10 to acquire the vehicle speed V based on the position information of the vehicle 100 acquired during the above reproduction test.

[0023] When acquiring the vehicle speed V (unit: km / h) from the position information of the vehicle 100, the vehicle state acquisition unit 15 of the mobile terminal 10 first acquires the position information (self-vehicle position information) of the vehicle 100 acquired by the GPS module G at the first time interval Tp during the reproduction test, and the sound pressure data extracted from the time-axis data of the sound acquired during the reproduction test (step S200). The sound pressure is an overall value (unit: Pascal) extracted at a predetermined second time interval Ts (for example, about several msec - 50 msec) shorter than the first time interval Tp from the time-axis data of the sound by the sound acquisition unit 14 or the arithmetic processing unit 16 after the completion of the reproduction test. However, the sound pressure acquired in step S200 may be a partial overall value or may be expressed by the common logarithm.

[0024] Furthermore, the vehicle status acquisition unit 15 sets the variable n, which indicates the order in which position information is acquired, to "1" (step S210), and then calculates the average vehicle speed Va(n) of the vehicle 100 between the acquisition timings tp(n) and tp(n+1) based on the nth and (n+1)th position information acquired in step S200 and the first time interval Tp (step S220). In step S220, the vehicle status acquisition unit 15 calculates the distance traveled by the vehicle 100 between the acquisition timings tp(n) and tp(n+1) from the nth and (n+1)th position information, and then calculates the average vehicle speed Va(n) by dividing the calculated distance traveled by the first time interval Tp.

[0025] Next, the vehicle state acquisition unit 15 estimates the vehicle speed V at the acquisition timings tp(n) and tp(n+1) of position information and the sound pressure acquisition timing ts(i) included between the acquisition timings tp(n) and tp(n+1) (where the variable i indicates the order in which sound pressure is acquired between the acquisition timings tp(n) and tp(n+1) of position information), and stores them in the auxiliary storage device M (step S230). In this embodiment, as shown in Figure 4, the vehicle state acquisition unit 15 assumes that the vehicle 100 is traveling at constant acceleration between the acquisition timings tp(n) and tp(n+1), and calculates the acceleration between the acquisition timings tp(n) and tp(n+1) based on the average vehicle speed Va(n) and the vehicle speed at the acquisition timing tp(n) (the vehicle speed at the acquisition timing tp(n+1) in the previous execution of step S230). Furthermore, the vehicle state acquisition unit 15 estimates the vehicle speed V at the position information acquisition timings tp(n) and tp(n+1), and the vehicle speed V at the sound pressure acquisition timing ts(i) included between the acquisition timings tp(n) and tp(n+1), from the calculated acceleration, average vehicle speed Va(n), and the first and second time intervals Tp and Ts. Note that the initial velocity at the start of position information acquisition (vehicle speed at time tp1 in Figure 4), which is necessary for calculating the acceleration between position information acquisition timings tp(1) and tp(2), can be calculated from the average vehicle speeds Va(1), Va(2), and Va(3) and the first time interval Tp. Also, in the example in Figure 4, the position information acquisition timings tp(n) and tp(n+1) coincide with the sound pressure acquisition timing, but they do not have to coincide.

[0026] Furthermore, the vehicle status acquisition unit 15 calculates the rate of change ΔV(n) of the vehicle speed V between the location information acquisition timings tp(n) and tp(n+1) (step S240). In step S240, the vehicle status acquisition unit 15 calculates the rate of change ΔV(n) of the vehicle speed V at the location information acquisition timing tp(n+1) estimated in step S230 by subtracting the vehicle speed V at the location information acquisition timing tp(n) estimated in step S230 from the vehicle speed V at the location information acquisition timing tp(n+1) estimated in step S230, and dividing the resulting difference by the first time interval Tp. Also, the vehicle status acquisition unit 15 sets the variable i to "1" (step S250) and calculates the rate of change ΔSP(i) of the sound pressure between the sound pressure acquisition timings ts(i) and ts(i+1) (step S260). In step S260, the vehicle state acquisition unit 15 calculates the rate of change of sound pressure ΔSP(i) by subtracting the sound pressure at acquisition timing ts(i) from the sound pressure at acquisition timing ts(i+1), and dividing the resulting difference by the second time interval Ts.

[0027] After the processing in step S260, the vehicle state acquisition unit 15 calculates the product P(i) of the rate of change ΔV(n) of vehicle speed V calculated in step S240 and the rate of change ΔSP(i) of sound pressure calculated in step S260, and the quotient Q(i) obtained by dividing the rate of change ΔV(n) of vehicle speed V calculated in step S240 by the rate of change ΔSP(i) of sound pressure calculated in step S260 (step S270). Furthermore, based on the product P(i) and quotient Q(i) calculated in step S270, the vehicle state acquisition unit 15 derives the estimation accuracy of vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 (step S280).

[0028] As shown in Figure 5, the vehicle state acquisition unit 15 determines whether the product value P(i) is positive when deriving the estimation accuracy of the vehicle speed V (step S281). If the product value P(i) is positive (step S281: YES), the vehicle state acquisition unit 15 determines whether the quotient Q(i) is greater than or equal to a predetermined lower limit Q0 and less than or equal to a predetermined upper limit Q1 (step S282). The lower limit Q0 and upper limit Q1 are predetermined after experimental analysis. If the quotient Q(i) falls within the range from the lower limit Q0 to the upper limit Q1 (step S282: YES), the vehicle state acquisition unit 15 sets the estimation accuracy of the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 to "high," indicating high accuracy (step S283).

[0029] In contrast, if the product value P(i) is a positive value but the quotient Q(i) is not within the range from the lower limit Q0 to the upper limit Q1 (step S282: NO), the vehicle state acquisition unit 15 sets the estimation accuracy of the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 to "medium," indicating that the accuracy is moderate (step S285). Also, if the product value P(i) is not a positive value (step S281: NO), the vehicle state acquisition unit 15 determines whether the quotient Q(i) is greater than or equal to the lower limit Q0 and less than or equal to the upper limit Q1 (step S284). If the quotient Q(i) is within the range from the lower limit Q0 to the upper limit Q1 (step S284: YES), the vehicle state acquisition unit 15 sets the estimation accuracy of the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 to "medium," indicating that the accuracy is moderate (step S285). Furthermore, if the quotient Q(i) is not within the range from the lower limit Q0 to the upper limit Q1 (step S284: NO), the vehicle state acquisition unit 15 sets the estimation accuracy of the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 to "low," indicating low accuracy (step S286).

[0030] In other words, when vehicle 100 is accelerating, the rate of change ΔV(n) of vehicle speed V becomes a positive value, and the rate of change ΔSP(i) of sound pressure becomes a positive value due to the increase in sound pressure of the sound generated by vehicle 100. Therefore, when vehicle 100 is accelerating, the product P(i) of the rate of change ΔV(n) of vehicle speed V and the rate of change ΔSP(i) of sound pressure becomes a positive value. Also, when vehicle 100 is accelerating, the quotient Q(i) obtained by dividing the rate of change ΔV(n) of vehicle speed V by the rate of change ΔSP(i) of sound pressure becomes a positive value, and if the vehicle speed V at the sound pressure acquisition timing ts(i) in step S230 is estimated with accuracy, it will fall within the predetermined range from the lower limit Q0 to the upper limit Q1.

[0031] On the other hand, when vehicle 100 is decelerating, the rate of change ΔV(n) of the vehicle speed V becomes a negative value, and the rate of change ΔSP(i) of the sound pressure becomes a negative value due to the decrease in sound pressure of the sound generated by vehicle 100. Therefore, even when vehicle 100 is decelerating, the product value P(i) becomes a positive value. Also, even when vehicle 100 is decelerating, the quotient Q(i) becomes a positive value, and if the vehicle speed V at the sound pressure acquisition timing ts(i) in step S230 is estimated with good accuracy, it will fall within the predetermined range from the lower limit Q0 to the upper limit Q1. Thus, if the product value P(i) is a positive value (step S281: YES) and the quotient Q(i) falls within the range from the lower limit Q0 to the upper limit Q1 (step S282: YES), it can be considered that the vehicle speed V at the sound pressure acquisition timing ts(i) in step S230 has been estimated with good accuracy (step S283).

[0032] Furthermore, if the rate of change ΔV(n) of vehicle speed V is positive and it is recognized that vehicle 100 is accelerating, but the sound pressure is decreasing (for example, between time tp2 and time tp3 in Figure 4), or if the rate of change ΔV(n) of vehicle speed V is negative and it is recognized that vehicle 100 is decelerating, but the sound pressure is increasing, then in step S230, the vehicle speed V at the sound pressure acquisition timing ts(i) may not be estimated accurately. Therefore, if the product value P(i) is a positive value (step S281: YES) and the quotient Q(i) is not within the range from the lower limit Q0 to the upper limit Q1 (step S282: NO), and if the product value P(i) is not a positive value (step S281: NO) and the quotient Q(i) is within the range from the lower limit Q0 to the upper limit Q1 (step S284: YES), then it can be considered that the vehicle speed V at the sound pressure acquisition timing ts(i) was estimated in step S230 with not very high accuracy (medium accuracy) (step S285). Furthermore, if the product value P(i) is not a positive value (step S281: NO) and the quotient Q(i) is not within the range from the lower limit Q0 to the upper limit Q1 (step S284: NO), then it can be considered that the estimation accuracy of the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 is low (step S286).

[0033] In step S280, i.e., in steps S283, S285, or S286, the vehicle state acquisition unit 15 derives the estimation accuracy of the vehicle speed V. Then, in step S230, it associates the information indicating the derived estimation accuracy with the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 and stores it in the auxiliary storage device M (step S290). Furthermore, the vehicle state acquisition unit 15 determines whether the variable i is greater than or equal to the total number Imax of sound pressure acquisition timings ts(i) included between the position information acquisition timings tp(n) and tp(n+1) (step S300). If the variable i is less than the total number Imax (step S300: NO), the vehicle state acquisition unit 15 increments the variable i (step S305) and then executes the processing in steps S260-S300 again.

[0034] Furthermore, if the variable i is greater than or equal to the total number Imax (step S300: YES), the vehicle status acquisition unit 15 determines whether the variable n is greater than or equal to the total number Nmax of location information acquired by the GPS module G (step S310). If the variable n is less than the total number Nmax (step S310: NO), the vehicle status acquisition unit 15 increments the variable n (step S315) and then executes the process from step S220 onwards again. When the variable n becomes greater than or equal to the total number Nmax (step S310: YES), the vehicle status acquisition unit 15 terminates the routine in Figure 3, thereby completing the estimation of the vehicle speed V based on the location information.

[0035] As described above, when the vehicle status acquisition unit 15 of the mobile terminal 10 constituting the abnormal noise diagnosis system 1 acquires the vehicle speed V of the vehicle 100 based on location information, it acquires the location information of the vehicle 100 acquired at the first time interval Tp by the GPS module G during the reproduction test and sound pressure data extracted (acquired) at the second time interval Ts from the time axis data of sound acquired during the reproduction test (step S200). Furthermore, the vehicle status acquisition unit 15, acting as a vehicle speed estimation unit, estimates the vehicle speed V at the location information acquisition timings tp(n) and tp(n+1) and the vehicle speed V at the sound pressure acquisition timing ts(i) included between the acquisition timings tp(n) and tp(n+1) based on the acquired location information and the first and second time intervals Tp and Ts (steps S220, S230).

[0036] Furthermore, the vehicle state acquisition unit 15, which acts as a vehicle speed change rate acquisition unit, acquires the rate of change ΔV(n) of the vehicle speed V between the location information acquisition timings tp(n) and tp(n+1) based on the estimated location information acquisition timings tp(n) and tp(n+1) and the first time interval Tp (step S240). Also, the vehicle state acquisition unit 15, which acts as a sound pressure change rate acquisition unit, calculates the rate of change ΔSP(i) of the sound pressure between the sound pressure acquisition timings ts(i) and ts(i+1) based on the acquired sound pressure and the second time interval Ts (step S260). Then, the vehicle state acquisition unit 15, which acts as an estimation accuracy acquisition unit, derives the estimation accuracy of the vehicle speed V in step S230 based on the rate of change ΔV(n) of the vehicle speed V and the rate of change ΔSP(i) of the sound pressure (steps S280, S281-S286), and links the derived estimation accuracy to the vehicle speed V at the estimated sound pressure acquisition timing ts(i) (step S290).

[0037] In other words, when vehicle 100 is accelerating, the sound pressure of the sound generated by vehicle 100 tends to increase. Therefore, if the rate of change ΔV(n) of vehicle speed V is positive and it is recognized that vehicle 100 is accelerating, but the sound pressure is decreasing, there is a possibility that the vehicle speed V is not estimated accurately in step S230. Also, when vehicle 100 is decelerating, the sound pressure of the sound generated by vehicle 100 tends to decrease. Therefore, if the rate of change ΔV(n) of vehicle speed V is negative and it is recognized that vehicle 100 is decelerating, but the sound pressure is increasing, there is a possibility that the vehicle speed V is not estimated accurately in step S230.

[0038] Therefore, the estimation accuracy of the vehicle speed V estimated in step S230 can be derived from the rate of change of vehicle speed V ΔV(n) and the rate of change of sound pressure ΔSP(i), as an appropriate one that accurately reflects the actual situation. Then, by linking the estimation accuracy derived from the rate of change of vehicle speed V ΔV(n) and the rate of change of sound pressure ΔSP(i) to the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230, it becomes possible to obtain useful vehicle speed V data from the location information of vehicle 100 and the sound data generated by vehicle 100. As a result, the mobile terminal 10 no longer needs to extract sound characteristic information or generate, classify, and store information for estimating vehicle speed associated with sound characteristic information in order to acquire vehicle speed V based on the location information of vehicle 100.

[0039] Furthermore, the vehicle state acquisition unit 15, which acts as an estimation accuracy acquisition unit, associates information indicating high estimation accuracy with the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 (S283, S290) if the product value P(i) of the rate of change of vehicle speed V ΔV(n) and the rate of change of sound pressure ΔSP(i) is a positive value (S281:YES), and the quotient Q(i) obtained by dividing the rate of change of vehicle speed V ΔV(n) by the rate of change of sound pressure ΔSP(i) falls within a predetermined range Qo-Q1 (S282:YES). Furthermore, if the product value P(i) is a positive value (S281:YES) and the quotient Q(i) is not within the range Qo-Q1 (S282:NO), or if the product value P(i) is not a positive value (S281:NO) and the quotient Q(i) is within the range Q0-Q1 (S284:YES), the vehicle state acquisition unit 15 associates information indicating that the estimation accuracy is moderate with the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 (S285, S290). Also, if the product value P(i) is not a positive value (S281:NO) and the quotient Q(i) is not within the range Q0-Q1 (S284:NO), the vehicle state acquisition unit 15 associates information indicating that the estimation accuracy is low with the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 (S286, S290).

[0040] This makes it possible to make the estimation accuracy information linked to the vehicle speed V estimated in step S230 appropriate and accurately reflect the actual situation. However, the processing in step S282 in Figure 5 may be omitted, and information indicating high estimation accuracy may be linked to the vehicle speed V at the sound pressure acquisition timing ts(i) estimated in step S230 when the product value P(i) is a positive value (S281:YES) and the quotient Q(i) is within the range Q0-Q1 (S284:YES).

[0041] Furthermore, in the abnormal noise diagnosis system 1, by placing the mobile terminal 10 in an appropriate location on the vehicle 100 and driving the vehicle 100, it becomes possible to synchronously acquire sound data emitted from the vehicle 100 and the vehicle speed V of the vehicle 100 based on location information using the mobile terminal 10, without connecting the mobile terminal 10 to the vehicle speed sensor or the like of the vehicle 100. In addition, when the abnormal noise diagnosis unit 21 of the server 20 constituting the abnormal noise diagnosis system 1 diagnoses abnormal noises generated in the vehicle 100 based on the sound data transmitted from the mobile terminal 10 and the vehicle speed V based on location information, it can select the vehicle speed V to be used for abnormal noise diagnosis based on the estimation accuracy associated with the vehicle speed V estimated by the mobile terminal 10. For example, it becomes possible to exclude vehicle speed V with low estimation accuracy and the sound pressure corresponding to that vehicle speed V from the abnormal noise diagnosis target. As a result, the abnormal noise diagnosis unit 21 can be made to diagnose abnormal noises based on the vehicle speed V accurately estimated from the location information of the vehicle 100, thereby improving the accuracy of abnormal noise diagnosis.

[0042] Furthermore, the quotient Q(i) calculated in step S270 of Figure 3 may be obtained by dividing the rate of change of sound pressure ΔSP(i) by the rate of change of vehicle speed V ΔV(n). Moreover, the procedure for estimating the vehicle speed V at the acquisition timing ts(i) of sound pressure included between the acquisition timings tp(n) and tp(n+1) of position information in step S230 is not limited to the above. That is, in step S230, the vehicle speed V may be estimated by any estimation method based on the position information at the acquisition timings tp(n) and tp(n+1) and the first and second time intervals Tp and Ts. Also, the routines shown in Figures 3 and 4 may be executed in real time when time-axis sound data is acquired by the reproduction test, or they may be executed by the abnormal sound diagnosis unit 21 of the server 20 after the reproduction test.

[0043] Furthermore, the invention disclosed herein is not limited in any way to the embodiments described above, and it goes without saying that various modifications can be made within the scope of this disclosure. Moreover, the embodiments described above are merely one specific form of the invention described in the summary of the invention, and do not limit the elements of the invention described in the summary of the invention. [Industrial applicability]

[0044] The invention disclosed herein can be used in the vehicle manufacturing industry and the like. [Explanation of Symbols]

[0045] 1 Abnormal noise diagnostic system, 10 mobile terminals, 14 sound acquisition unit, 15 vehicle status acquisition unit, 20 server, 21 abnormal noise diagnostic unit (diagnostic device), 100 vehicle, G GPS module.

Claims

1. A vehicle speed acquisition device that acquires the vehicle speed based on the vehicle's location information, A location information acquisition unit that acquires the location information at predetermined first time intervals, A sound pressure acquisition unit that acquires the sound pressure of sounds emitted from the vehicle at a second time interval shorter than the first time interval, A vehicle speed estimation unit estimates the vehicle speed at the timing of acquisition of the location information and the vehicle speed at the timing of acquisition of the sound pressure, based on the location information acquired by the location information acquisition unit and the first and second time intervals. A vehicle speed change rate acquisition unit acquires the rate of change of the vehicle speed between the location information acquisition timings based on the vehicle speed at the location information acquisition timing estimated by the vehicle speed estimation unit and the first time interval, A sound pressure change rate acquisition unit acquires the rate of change of the sound pressure between sound pressure acquisition timings based on the sound pressure acquired by the sound pressure acquisition unit and the second time interval, An estimation accuracy acquisition unit acquires the vehicle speed estimation accuracy of the vehicle speed estimation unit based on the rate of change of the vehicle speed and the rate of change of the sound pressure, and links the acquired estimation accuracy to the vehicle speed at the timing of acquiring the sound pressure estimated by the vehicle speed estimation unit. A vehicle speed acquisition device equipped with the following features.

2. In the vehicle speed acquisition device according to claim 1, The vehicle speed acquisition device includes an estimation accuracy acquisition unit that, when the product of the rate of change of the vehicle speed and the rate of change of the sound pressure is a positive value, associates information indicating high estimation accuracy with the vehicle speed at the timing of sound pressure acquisition estimated by the vehicle speed estimation unit.

3. In the vehicle speed acquisition device according to claim 1, The vehicle speed acquisition device, when the quotient obtained by dividing the rate of change of the vehicle speed and the rate of change of the sound pressure by the other falls within a predetermined range, associates information indicating high estimation accuracy with the vehicle speed at the timing of acquisition of the sound pressure estimated by the vehicle speed estimation unit.

4. In the vehicle speed acquisition device according to claim 1, The vehicle speed acquisition device includes the vehicle speed acquisition unit which, if the product of the rate of change of the vehicle speed and the rate of change of the sound pressure is a positive value and the quotient obtained by dividing one of the rate of change of the vehicle speed and the rate of change of the sound pressure by the other falls within a predetermined range, associates information indicating high estimation accuracy with the vehicle speed at the timing of sound pressure acquisition estimated by the vehicle speed estimation unit; if the product is a positive value and the quotient does not fall within the range, and if the product is not a positive value and the quotient falls within the range, associates information indicating moderate estimation accuracy with the vehicle speed at the timing of sound pressure acquisition estimated by the vehicle speed estimation unit; and if the product is not a positive value and the quotient does not fall within the range, associates information indicating low estimation accuracy with the vehicle speed at the timing of sound pressure acquisition estimated by the vehicle speed estimation unit.

5. An abnormal noise diagnostic system including a vehicle speed acquisition device according to any one of claims 1 to 4, A portable terminal that can acquire the aforementioned location information and sound data emitted from the vehicle, and includes the vehicle speed acquisition device, The system comprises a diagnostic device built using machine learning to diagnose abnormal noises generated in the vehicle based on the sound data transmitted from the mobile terminal and the vehicle speed obtained by the vehicle speed acquisition device, The diagnostic device is an abnormal noise diagnostic system that selects the vehicle speed to be used for diagnosing the abnormal noise based on the estimation accuracy linked to the vehicle speed from the mobile terminal.

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