Vehicle speed acquisition device, and abnormal sound 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 speed of a vehicle based on position information of the vehicle, and an abnormal sound diagnosis system including the same. [Background technology]

[0002] Conventionally, there is known a navigation device that detects the vehicle speed based on the reception result of radio waves from GPS satellites (for example, see Patent Document 1). This navigation device collects sound at a predetermined position on the vehicle, acquires the inclination angle of the vehicle's travel route, and extracts characteristic information of the sound collection result corresponding to the vehicle speed for each inclination angle based on the detection result of the vehicle speed and the sound collection result. Furthermore, the navigation device classifies and stores sound collection characteristic information that associates the vehicle speed with the characteristic information for each inclination angle, and when it is unable to receive radio waves from the number of GPS satellites required to detect the vehicle speed, it estimates the vehicle speed taking into consideration the sound collection result, the inclination angle of the travel route, and the sound collection characteristic information. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4972211 Summary of the Invention [Problem to be solved by the invention]

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

[0005] Therefore, a main object of the present disclosure is to make it possible to acquire useful vehicle speed data from vehicle position information and data on sounds generated by the vehicle. [Means for solving the problem]

[0006] A vehicle speed acquisition device according to the present disclosure is a vehicle speed acquisition device that acquires the speed of a vehicle based on position information of the vehicle, and includes a position information acquisition unit that acquires the position information at a predetermined first time interval, a sound pressure acquisition unit that acquires sound pressure of sound 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 a timing when the position information is acquired and the vehicle speed at a timing when the sound pressure is acquired based on the position information acquired by the position information acquisition unit and the first and second time intervals, and a vehicle speed estimation unit that estimates the vehicle speed at the timing when the position information is acquired based on the position information acquired by the position information acquisition unit and the first and second time intervals. a vehicle speed change rate acquisition unit that acquires a rate of change in the vehicle speed between acquisition timings of the position information based on the vehicle speed in the location information acquisition unit and the first time interval; a sound pressure change rate acquisition unit that acquires a rate of change in the sound pressure between acquisition timings of 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 an estimation accuracy of the vehicle speed by the vehicle speed estimating 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 estimated by the vehicle speed estimating unit at the acquisition timing of the sound pressure.

[0007] The abnormal sound diagnosis system disclosed herein is an abnormal sound diagnosis system that includes the vehicle speed acquisition device described above, and is capable of acquiring the location information and data on sound emitted from the vehicle, and also includes a mobile terminal that includes the vehicle speed acquisition device, and a diagnostic device constructed by machine learning to diagnose abnormal sounds 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, and the diagnostic device selects the vehicle speed to be used in diagnosing the abnormal sound based on the estimation accuracy linked to the vehicle speed from the mobile terminal. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram showing an abnormal sound diagnosis system according to the present disclosure. [Diagram 2] 4 is a flowchart for explaining an abnormal sound diagnosis procedure performed by the abnormal sound diagnosis system of the present disclosure. [Diagram 3] 5 is a flowchart for explaining a procedure for acquiring the vehicle speed by a mobile terminal constituting the abnormal sound diagnosis system of the present disclosure. [Figure 4] 4 is a time chart for explaining a procedure for acquiring the vehicle speed of a vehicle by a mobile terminal constituting the abnormal sound diagnosis system of the present disclosure. [Diagram 5] 5 is a flowchart for explaining a procedure for deriving the estimation accuracy of the vehicle speed by the mobile terminal constituting the abnormal sound diagnosis system of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Next, an embodiment of the present disclosure will be described with reference to the drawings.

[0010] 1 is a schematic diagram showing an abnormal sound diagnosis system 1 according to the present disclosure. The abnormal sound diagnosis system 1 shown in the figure is for diagnosing the cause of abnormal sounds generated in a vehicle 100, such as a vehicle equipped with only an engine as a power source, a hybrid vehicle (HEV, PHEV), or an electric vehicle (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 a worker (user of the abnormal sound diagnosis system 1) at a vehicle dealership, a repair shop, or the like when responding to a user (owner) of the vehicle 100 in which an abnormal sound has occurred, or when carrying out a reproduction test in which the vehicle 100 is driven (operated) on a roadway or a test bench to reproduce the abnormal sound. In this embodiment, the mobile terminal 10 is a so-called smartphone, and includes an SoC, a ROM, a RAM, a GPS module (location information acquisition unit) G, an auxiliary storage device (flash memory) M, a touch panel display unit 11, a communication module 12 capable of exchanging various information with a server 20 or an electronic control device of the vehicle 100 via wired or wireless communication, a microphone (not shown), and the like. In addition, an abnormal sound diagnosis support application (program) is installed in the mobile terminal 10. As shown in FIG. 1, the mobile terminal 10 includes a medical interview information acquisition unit 13, a sound acquisition unit 14, a vehicle state acquisition unit 15, a calculation processing unit 16, an extraction unit 17, and a display control unit 18, which are constructed through cooperation between an abnormal sound diagnosis support application (software) and hardware such as the SoC of the mobile terminal 10.

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

[0013] The vehicle state acquisition unit 15 acquires information indicating the state of the vehicle 100 (hereinafter referred to as "vehicle state data") in synchronization with the acquisition of time axis data of the sound by the sound acquisition unit 14 when the reproduction test is performed, and executes processing on the acquired vehicle state data. The vehicle state data includes a plurality of physical quantities, such as the vehicle speed V and the engine speed Ne, corresponding to the items of the medical interview information. In this embodiment, the vehicle state acquisition unit 15 acquires the vehicle state data from an electronic control device of the vehicle 100 to which the mobile terminal 10 is connected via a cable or the like. In addition, the vehicle state acquisition unit 15 can 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 executes analysis processing of the time axis data of the sound acquired by the sound acquisition unit 14. The extraction unit 17 executes narrowing down the analysis results by the calculation processing unit 16 according to the selection of the operator or the like. The display control unit 18 controls the display unit 11.

[0014] The server 20 of the abnormal sound diagnosis system 1 is a computer (information processing device) including a CPU, ROM, RAM, input / output devices, a communication module, etc., and is installed and managed, for example, by an automobile manufacturer that manufactures the vehicle 100. In the server 20, an abnormal sound diagnosis unit 21 is constructed as a diagnostic device that diagnoses abnormal sounds generated in the vehicle 100 by cooperation of hardware such as a CPU and a pre-installed abnormal sound diagnosis application. The abnormal sound diagnosis unit 21 includes a neural network (convolutional neural network) constructed by supervised learning (machine learning) so as to diagnose the cause of the abnormal sound generated in the vehicle 100 and the part that is the source of the abnormal sound based on the interview information, sound time axis data, vehicle condition data, etc. acquired by the mobile terminal 10. In addition, in the server 20, when the occurrence of a new abnormal sound in the vehicle 100 is found, re-learning of the abnormal sound diagnosis unit 21 is executed using the sound time axis data acquired for the new abnormal sound and the contents of each item of the interview information, etc., as teacher data.

[0015] Furthermore, the server 20 includes a storage device 22 that stores a database that stores information on multiple abnormal sounds that are known to occur in a vehicle for each vehicle model. The database stores information such as time axis data of the sound, the cause of the abnormal sound, the part that is the source of the sound, the contents of the medical interview information provided by the user, etc., and measures to eliminate the abnormal sound, for each of the multiple abnormal sounds, in association with the abnormal sounds. The server 20 also updates the database based on information acquired from many vehicles including the vehicle 100, and information on newly discovered abnormal sounds transmitted from automobile manufacturers (developers, etc.), vehicle dealers, repair shops, etc.

[0016] Next, an abnormal sound diagnosis procedure by the abnormal sound diagnosis system 1 will be described with reference to FIG. 2. When a worker at a vehicle dealership, repair shop, or the like is requested by a user of the vehicle 100 to eliminate an abnormal sound, the worker listens to medical information from the user and then performs a reproduction test to obtain information necessary for diagnosing the abnormal sound. When performing the reproduction test, the worker connects the mobile terminal 10 to the electronic control device of the vehicle 100, or places or fixes the mobile terminal 10 or an external microphone connected to the mobile terminal 10 at an appropriate position on the vehicle 100 without connecting the mobile terminal 10 to the electronic control device of the vehicle 100. The worker also starts an abnormal sound diagnosis support application and turns on the start switch of the vehicle 100. Accordingly, the mobile terminal 10 obtains information such as the vehicle identification number or chassis number of the vehicle 100 from the electronic control device. Furthermore, the worker taps the recording start button displayed on the display unit 11 and drives (operates) the vehicle 100 on the roadway or on a test stand to reproduce the driving conditions in which the abnormal noise occurred based on medical information from the user of the vehicle 100, etc.

[0017] While the vehicle 100 is running (operating), the sound acquisition unit 14 of the mobile terminal 10 acquires time axis data of the sound emitted from the vehicle 100 and stores it in the auxiliary storage device M. In addition, the vehicle state acquisition unit 15 acquires vehicle state data designated by the worker according to the medical interview information from the electronic control device of the vehicle 100 in synchronization with the acquisition of the time axis data of the sound by the sound acquisition unit 14, and stores it in the auxiliary storage device M. Furthermore, when the mobile terminal 10 is not connected to the electronic control device of the vehicle 100, the GPS module G acquires position information of the vehicle 100 (own vehicle position information) at a first time interval Tp (for example, about 0.5 to 1 second) that is predetermined, and the acquired position information is stored in the auxiliary storage device M. Then, when the worker taps the recording stop button displayed on the display unit 11, the acquisition of the time axis data of the sound, the vehicle state data, and the like is completed, and the mobile terminal 10 executes a series of processes shown in FIG. 2. In addition, when the mobile terminal 10 is not connected to the electronic control device of the vehicle 100, the vehicle state acquisition unit 15 of the mobile terminal 10 acquires (estimates) the vehicle speed V of the vehicle 100 based on the position information acquired by the GPS module G after the recording stop button is tapped and before the processing of Figure 2 is started.

[0018] 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 performs STFT (Short-Time Fourier Transform) on the acquired time axis data of the sound to acquire a spectrogram (acoustic spectrogram) showing the relationship between time, frequency, and sound pressure (step S110). In addition, the display control unit 18 of the mobile terminal 10 causes the display unit 11 to display the spectrogram acquired by the arithmetic processing unit 16 (step S120). The spectrogram is a color map in which the horizontal axis is the time axis and the vertical axis is the frequency axis, and the sound pressure level is color-coded to show the relationship between time and sound pressure level for each frequency.

[0019] When the spectrogram is displayed on the display unit 11 of the mobile terminal 10, the worker selects (specifies) on the display unit 11 a range of the spectrogram that should be diagnosed (analyzed) by the abnormal sound diagnosis unit 21 (server 20) (hereinafter referred to as the "diagnosis range"). In response to the worker's screen operation, the extraction unit 17 acquires the diagnosis range selected by the worker, and instructs the display control unit 18 to display the diagnosis range on the display unit 11 (step S130). The extraction unit 17 also reads out vehicle condition data (including the vehicle speed V acquired based on the position information) within the diagnosis range (step S140), and extracts information to be provided to the server 20 as medical inquiry information from the read vehicle condition data (step S150).

[0020] After the process of step S150, the display control unit 18 causes the display unit 11 to display a message instructing input of medical inquiry information, and after the worker has completed input of the medical inquiry information, the medical inquiry information acquisition unit 13 confirms the information extracted in step S150 and the information input by the worker as the final medical inquiry information (step S160). When the medical inquiry information is confirmed and the worker taps an information transmission button displayed on the display unit 11, information necessary for diagnosing the abnormal sound is transmitted from the communication module 12 of the mobile terminal 10 to the server 20 (step S170). In this embodiment, the information transmitted from the mobile terminal 10 to the server 20 includes at least the time axis data of the sound, the medical inquiry information, the vehicle state data, and information defining the diagnosis range selected by the worker.

[0021] When the information required for diagnosing the abnormal sound is transmitted from the mobile terminal 10 to the server 20, the abnormal sound diagnosis unit 21 of the server 20 diagnoses the cause of the abnormal sound 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 sound generated in the vehicle 100, the part that is the source of the abnormal sound, and measures to eliminate the abnormal sound read from the storage device 22. 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 for diagnosing the abnormal sound is completed. By executing the process shown in FIG. 2, the worker can accurately explain the diagnosis result from the server 20 to the user of the vehicle 100 and promptly proceed with measures to deal with the abnormal sound.

[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 while the reproduction test is being performed.

[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 of the vehicle 100 (own vehicle position information) acquired at the first time interval Tp by the GPS module G while the reproduction test is being performed, and the sound pressure data extracted from the time axis data of the sound acquired while the reproduction test is being performed (step S200). The sound pressure is an overall value (unit: Pascal) extracted by the sound acquisition unit 14 or the calculation processing unit 16 from the time axis data of the sound at predetermined second time intervals Ts (for example, about several msec to 50 msec) shorter than the first time interval Tp after the reproduction test is completed. However, the sound pressure acquired in step S200 may be a partial all value, or may be expressed by common logarithm.

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

[0025] Next, the vehicle state acquisition unit 15 estimates the vehicle speed V (where the variable i indicates the acquisition order of the sound pressure between the acquisition times tp(n) and tp(n+1) of the position information) at the acquisition timing ts(i) of the sound pressure included between the acquisition times tp(n) and tp(n+1) of the position information, and stores the vehicle speed V in the auxiliary storage device M (step S230). In this embodiment, as shown in FIG. 4, the vehicle state acquisition unit 15 assumes that the vehicle 100 travels at a constant acceleration between the acquisition times tp(n) and tp(n+1) of the position information, and calculates the acceleration between the acquisition times 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) when step S230 was previously executed). Furthermore, the vehicle state acquisition unit 15 estimates the vehicle speed V at the acquisition timings tp(n) and tp(n+1) of the position information and the vehicle speed V at the acquisition timing ts(i) of the sound pressure 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 speed (vehicle speed at time tp1 in FIG. 4) at the start of acquisition of the position information required for calculating the acceleration between the acquisition timings tp(1) and tp(2) of the position information can be calculated from the average vehicle speeds Va(1), Va(2), and Va(3) and the first time interval Tp. In the example of FIG. 4, the acquisition timings tp(n) and tp(n+1) of the position information coincide with the acquisition timing of the sound pressure, but the two do not have to coincide.

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

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

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

[0029] On the other hand, even if the product value P(i) is a positive value, if 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 acquisition timing ts(i) of the sound pressure estimated in step S230 to "medium" indicating that the accuracy is medium (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 equal to or greater than the lower limit Q0 and equal to or less than 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 acquisition timing ts(i) of the sound pressure estimated in step S230 to "medium" indicating that the accuracy is medium (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 acquisition timing ts(i) of the sound pressure estimated in step S230 to “low”, indicating low accuracy (step S286).

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

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

[0032] Furthermore, if the sound pressure is decreasing even though the rate of change ΔV(n) of the vehicle speed V is a positive value and it is recognized that the vehicle 100 is accelerating (for example, between time tp2 and time tp3 in FIG. 4), or if the sound pressure is increasing even though the rate of change ΔV(n) of the vehicle speed V is a negative value and it is recognized that the vehicle 100 is decelerating, there is a risk that the vehicle speed V at the sound pressure acquisition timing ts(i) in step S230 has not been accurately estimated. 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), it can be considered that the vehicle speed V at the sound pressure acquisition timing ts(i) in step S230 is estimated with a low accuracy (medium accuracy) (step S285). 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), 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] When the vehicle state acquisition unit 15 derives the estimation accuracy of the vehicle speed V in step S280, i.e., step S283, S285, or S286, the vehicle state acquisition unit 15 associates information indicating the derived estimation accuracy with the vehicle speed V at the acquisition timing ts(i) of the sound pressure 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 equal to or greater than the total number Imax of sound pressure acquisition timings ts(i) included between the acquisition timings tp(n) and tp(n+1) of the position information (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 processes of steps S260-S300 again.

[0034] Furthermore, if the variable i is equal to or greater than the total number Imax (step S300: YES), the vehicle state acquisition unit 15 determines whether the variable n is equal to or greater than the total number Nmax of pieces 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 state acquisition unit 15 increments the variable n (step S315) and then executes the processes from step S220 onwards again. Then, if the variable n becomes equal to or greater than the total number Nmax (step S310: YES), the vehicle state acquisition unit 15 ends the routine in FIG. 3, thereby completing the estimation of the vehicle speed V based on the location information.

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

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

[0037] That is, when the vehicle 100 is accelerating, the sound pressure of the sound generated by the vehicle 100 tends to increase, so if the rate of change ΔV(n) of the vehicle speed V is a positive value and the vehicle 100 is recognized as accelerating, but the sound pressure is decreasing, the vehicle speed V may not be accurately estimated in step S230. Also, when the vehicle 100 is decelerating, the sound pressure of the sound generated by the vehicle 100 tends to decrease, so if the rate of change ΔV(n) of the vehicle speed V is a negative value and the vehicle 100 is recognized as decelerating, but the sound pressure is increasing, the vehicle speed V may not be accurately estimated in step S230.

[0038] Therefore, the estimation accuracy of the vehicle speed V estimated in step S230 can be derived as an appropriate value that reflects the actual situation well from the change rate ΔV(n) of the vehicle speed V and the change rate ΔSP(i) of the sound pressure. By linking the estimation accuracy derived from the change rate ΔV(n) of the vehicle speed V and the change rate ΔSP(i) of the sound pressure estimated in step S230 to the vehicle speed V at the acquisition timing ts(i) of the sound pressure, it becomes possible to acquire useful data of the vehicle speed V from the position information of the vehicle 100 and data of the sound generated by the vehicle 100. As a result, in the mobile terminal 10, in order to acquire the vehicle speed V based on the position information of the vehicle 100, it becomes unnecessary to extract sound characteristic information or generate, classify, and store information for estimating the vehicle speed associated with the sound characteristic information.

[0039] Furthermore, when the product value P(i) of the rate of change ΔV(n) of vehicle speed V and the rate of change ΔSP(i) of sound pressure is a positive value (S281: YES), and 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 is within a predetermined range Qo-Q1 (S282: YES), the vehicle state acquisition unit 15, serving as an estimation accuracy acquisition unit, links information indicating high estimation accuracy to the vehicle speed V at the acquisition timing ts(i) of the sound pressure estimated in step S230 (S283, S290). Furthermore, when 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), and when 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 links information indicating that the estimation accuracy is medium to the vehicle speed V at the acquisition timing ts(i) of the sound pressure estimated in step S230 (S285, S290). When 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 links information indicating that the estimation accuracy is low to the vehicle speed V at the acquisition timing ts(i) of the sound pressure estimated in step S230 (S286, S290).

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

[0041] Furthermore, in the abnormal sound diagnosis system 1, if the mobile terminal 10 is placed at an appropriate position on the vehicle 100 and the vehicle 100 is driven, the data of the sound emitted from the vehicle 100 and the vehicle speed V of the vehicle 100 based on the position information can be acquired synchronously by the mobile terminal 10 without connecting the mobile terminal 10 to a vehicle speed sensor of the vehicle 100. Furthermore, when diagnosing an abnormal sound generated in the vehicle 100 based on the data of the sound transmitted from the mobile terminal 10 and the vehicle speed V based on the position information, the abnormal sound diagnosis unit 21 of the server 20 constituting the abnormal sound diagnosis system 1 can select the vehicle speed V to be used for diagnosing the abnormal sound based on the estimation accuracy linked to the vehicle speed V estimated by the mobile terminal 10. For example, it becomes possible to exclude the vehicle speed V with low estimation accuracy and the sound pressure corresponding to the vehicle speed V from the abnormal sound diagnosis target. This allows the abnormal sound diagnosis unit 21 to diagnose the abnormal sound based on the vehicle speed V estimated with high accuracy from the position information of the vehicle 100, thereby making it possible to further improve the accuracy of the abnormal sound diagnosis.

[0042] The quotient Q(i) calculated in step S270 of FIG. 3 may be obtained by dividing the rate of change ΔSP(i) of sound pressure by the rate of change ΔV(n) of vehicle speed V. Furthermore, the procedure for estimating the vehicle speed V at the acquisition timings tp(n), tp(n+1) of position information and the acquisition timing ts(i) of sound pressure included between the acquisition timings tp(n), tp(n+1) 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), tp(n+1) and the first and second time intervals Tp, Ts. Furthermore, the routines shown in FIG. 3 and FIG. 4 may be executed in real time when the time axis data of the sound is acquired by the reproduction test, or may be executed by the abnormal sound diagnosis unit 21 of the server 20 after the reproduction test.

[0043] The present disclosure is not limited to the above embodiment, and various modifications can be made within the scope of the present disclosure. Furthermore, the above embodiment is merely a specific form of the invention described in the Summary of the Invention, and does not limit the elements of the invention described in the Summary of the Invention. [Industrial Applicability]

[0044] The present disclosure is applicable to the vehicle manufacturing industry and the like. [Explanation of symbols]

[0045] 1 Abnormal sound diagnosis system, 10 Mobile terminal, 14 Sound acquisition unit, 15 Vehicle state acquisition unit, 20 Server, 21 Abnormal sound diagnosis unit (diagnostic device), 100 Vehicle, G GPS module.

Claims

1. A vehicle speed acquisition device that acquires a vehicle speed based on vehicle position information, a location information acquisition unit that acquires the location information at a predetermined first time interval; a sound pressure acquisition unit that acquires a sound pressure of a sound emitted from the vehicle at a second time interval that is shorter than the first time interval; a vehicle speed estimation unit that estimates the vehicle speed at a timing of acquiring the position information and the vehicle speed at a timing of acquiring the sound pressure based on the position information acquired by the position information acquisition unit and the first and second time intervals; a vehicle speed change rate acquisition unit that acquires a change rate of the vehicle speed between acquisition times of the position information based on the vehicle speed at the acquisition times estimated by the vehicle speed estimation unit and the first time interval; a sound pressure change rate acquisition unit that acquires a change rate of the sound pressure between acquisition timings of the sound pressure based on the sound pressure acquired by the sound pressure acquisition unit and the second time interval; an estimation accuracy acquisition unit that acquires an estimation accuracy of the vehicle speed by the vehicle speed estimator based on the rate of change of the vehicle speed and the rate of change of the sound pressure, and associates the acquired estimation accuracy with the vehicle speed at the acquisition timing of the sound pressure estimated by the vehicle speed estimator; A vehicle speed acquisition device comprising:

2. The vehicle speed acquisition device according to claim 1, The estimation accuracy acquisition unit is a vehicle speed acquisition device that, when the product of the change rate of the vehicle speed and the change rate of the sound pressure is a positive value, links information indicating that the estimation accuracy is high to the vehicle speed at the time of acquiring the sound pressure estimated by the vehicle speed estimation unit.

3. The vehicle speed acquisition device according to claim 1, The estimation accuracy acquisition unit is a vehicle speed acquisition device that, when a quotient obtained by dividing one of the change rate of the vehicle speed and the change rate of the sound pressure by the other is within a predetermined range, links information indicating that the estimation accuracy is high to the vehicle speed at the time of acquiring the sound pressure estimated by the vehicle speed estimation unit.

4. The vehicle speed acquisition device according to claim 1, the estimation accuracy acquisition unit links information indicating that the estimation accuracy is high to the vehicle speed at the time when the sound pressure estimated by the vehicle speed estimation unit is acquired if the product value of the rate of change of the vehicle speed and the rate of change of the sound pressure is a positive value and a 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 is within a predetermined range; links information indicating that the estimation accuracy is medium to the vehicle speed at the time when the sound pressure estimated by the vehicle speed estimation unit is acquired if the product value is a positive value and the quotient is not within the range, and if the product value is not a positive value and the quotient is within the range; and links information indicating that the estimation accuracy is low to the vehicle speed at the time when the sound pressure estimated by the vehicle speed estimation unit is acquired if the product value is not a positive value and the quotient is not within the range.

5. An abnormal sound diagnosis system including the vehicle speed acquisition device according to any one of claims 1 to 4, A mobile terminal capable of acquiring the position information and data of a sound emitted from the vehicle and including the vehicle speed acquisition device; a diagnostic device constructed by machine learning to diagnose an abnormal sound occurring in the vehicle based on the sound data transmitted from the mobile terminal and the vehicle speed acquired by the vehicle speed acquisition device, The diagnostic device is an abnormal sound diagnostic system that selects the vehicle speed to be used for diagnosing the abnormal sound based on the estimation accuracy linked to the vehicle speed from the mobile terminal.

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