Road surface evaluation device

Abstract

To evaluate road surface profiles efficiently with good accuracy.SOLUTION: A road surface evaluation device 10 comprises: an information acquisition unit 111 that acquires travel information on a plurality of vehicles and map information including information on a road which the plurality of vehicles have traveled; an evaluation unit 112 that calculates a roughness index indicating the roughness of a road surface corresponding to a prescribed period on the basis of the travel information on the plurality of vehicles having traveled the road in a prescribed period acquired by the information acquisition unit 111; and an output unit 113 that outputs roughness information including the roughness value in association with the road information. When the evaluation unit 112 calculates a roughness index corresponding to a change of roughness value corresponding to a second prescribed period after the first prescribed period, and when it estimates that a change rate of roughness value corresponding to the second prescribed period with respect to the roughness value corresponding to the first prescribed period exceeds a prescribed threshold, the information acquisition unit 111 acquires many more travel information to be used for calculation of a roughness value corresponding to the second prescribed period than when it is estimated that the change rate is smaller than or equal to the prescribed threshold.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a road surface evaluation device that evaluates a road surface profile that represents the uneven shape of a road surface. [Background technology]

[0002] Conventionally, one such device known in the art is one that evaluates the roughness of a road surface based on driving information, including driving acceleration, obtained from multiple vehicles traveling on the road (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 059636 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a method of evaluating road surface roughness based on driving information obtained from multiple vehicles, such as the device described in Patent Document 1, when the number of vehicles increases, the amount of data increases, which may increase the load on the device and communication infrastructure. [Means for solving the problem]

[0005] A road surface evaluation device according to one aspect of the present invention includes a travel information acquisition unit that acquires travel information of each of a plurality of vehicles, including acceleration information indicating the acceleration of the plurality of vehicles, a map information acquisition unit that acquires map information including information on the road on which the plurality of vehicles have traveled, a calculation unit that calculates a roughness value indicating the roughness of the road surface of a road corresponding to a predetermined period based on the travel information of the plurality of vehicles that have traveled on the road during the predetermined period acquired by the travel information acquisition unit, and an output unit that outputs the roughness information including the roughness value calculated by the calculation unit in association with the information on the road acquired by the map information acquisition unit. When the calculation unit calculates a roughness value corresponding to a second predetermined period that is later than the first predetermined period, the travel information acquisition unit estimates whether or not a rate of change of the roughness value corresponding to the second predetermined period relative to the roughness value corresponding to the first predetermined period calculated by the calculation unit exceeds a predetermined threshold, and acquires more travel information to be used for calculating the roughness value corresponding to the second predetermined period when it estimates that the rate of change exceeds the predetermined threshold than when it estimates that the rate of change is equal to or less than the predetermined threshold. Effect of the Invention

[0006] According to the present invention, a road surface profile can be evaluated efficiently and accurately. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of the configuration of a road surface evaluation system including a road surface evaluation device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a configuration of a main part of the in-vehicle device. [Diagram 3] FIG. 2 is a block diagram showing the configuration of a main part of a driving information storage device. [Figure 4] 1 is a block diagram showing a configuration of a main part of a road surface evaluation device according to an embodiment of the present invention. [Diagram 5] FIG. 2 is a diagram showing an example of a map of roads on which a vehicle travels. [Figure 6] FIG. 4 is a diagram showing an example of travel information. [Figure 7] FIG. 4 is a diagram showing an example of combined travel information. [Figure 8A] FIG. 4 is a diagram for explaining a method of deriving the correlation between a road surface roughness value and a lateral acceleration. [Figure 8B] FIG. 4 is a diagram for explaining a method of deriving the correlation between a road surface roughness value and a lateral acceleration. [Figure 9A] FIG. 4 is a diagram showing an example of road surface profile information. [Figure 9B] FIG. 11 is a diagram showing another example of road surface profile information. [Figure 9C] FIG. 11 is a diagram showing another example of road surface profile information. [Figure 10A] FIG. 9B is a diagram for explaining the change in road surface roughness at point A in FIG. 9A. [Figure 10B] FIG. 9B is a diagram for explaining the change in road surface roughness at point A in FIG. 9A. [Figure 11] 4 is a flowchart showing an example of processing executed by a calculation unit in FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 11. A road surface evaluation device according to an embodiment of the present invention is a device for evaluating a road surface profile of a road on which a vehicle travels. Fig. 1 is a diagram showing an example of the configuration of a road surface evaluation system including a road surface evaluation device according to this embodiment. As shown in Fig. 1, the road surface evaluation system 1 includes a road surface evaluation device 10, an in-vehicle terminal 30, and a travel information storage device (hereinafter simply referred to as a storage device) 40. The road surface evaluation device 10 and the storage device 40 are configured, for example, by a server device. The in-vehicle terminal 30 is configured to be able to communicate with the road surface evaluation device 10 and the storage device 40 via a communication network 2.

[0009] The communication network 2 includes not only public wireless communication networks such as the Internet and mobile phone networks, but also closed communication networks established for each designated management area, such as wireless LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark), etc.

[0010] The in-vehicle terminal 30 is mounted on a vehicle 20. The vehicles 20 include a plurality of vehicles 20-1, 20-2, . . . , 20-n. The vehicles 20 may be manually driven vehicles or automatically driven vehicles. The vehicles 20 may include vehicles of different models and grades.

[0011] 2 is a block diagram showing the main configuration of the in-vehicle terminal 30 according to this embodiment. The in-vehicle terminal 30 includes an electronic control unit (ECU) 31, a positioning sensor 32, an acceleration sensor 33, a steering angle sensor 34, a vehicle speed sensor 35, and a TCU (Telematic Control Unit) 36.

[0012] The positioning sensor 32 is, for example, a GPS sensor that receives a positioning signal transmitted from a GPS satellite and detects the absolute position (latitude, longitude, etc.) of the vehicle 20. The positioning sensor 32 includes not only a GPS sensor but also a sensor that performs positioning using radio waves transmitted from satellites of various countries called GNSS satellites, including quasi-zenith orbit satellites.

[0013] The acceleration sensor 33 detects acceleration in the left-right direction, i.e., lateral acceleration, of the vehicle 20. The acceleration sensor 33 may be configured to detect acceleration in the front-rear direction and acceleration in the up-down direction as well as the lateral acceleration of the vehicle 20. The steering angle sensor 34 detects the steering angle of a steering wheel (not shown) of the vehicle 20. The vehicle speed sensor 35 detects the vehicle speed of the vehicle 20.

[0014] 2, the ECU 31 includes a computer having a calculation unit 310 such as a CPU, a storage unit 320 such as a ROM, a RAM, and other peripheral circuits (not shown) such as an I / O interface. The calculation unit 310 functions as a sensor value acquisition unit 311 and a communication control unit 312 by executing a program stored in advance in the storage unit 320.

[0015] The sensor value acquisition unit 311 acquires the detection values ​​of the sensors 33-35 and the absolute position of the vehicle 20 detected by the positioning sensor 32 at a predetermined period. The communication control unit 312 transmits the information acquired by the sensor value acquisition unit 311 (hereinafter referred to as traveling information) together with a vehicle ID capable of identifying the vehicle 20 to the communication network 2 via the TCU 36 at a predetermined period.

[0016] The road surface evaluation device 10 detects the uneven shape of the road surface, that is, the roughness of the road surface (hereinafter also referred to as the road surface profile) based on the detection value of the acceleration sensor 33 of the vehicle 20 (vehicle-mounted terminal 30). Information on this detected road surface profile is output to a terminal owned by a road management company or the like, and is used as reference data when the road management company or the like considers the need for repairs, etc. In other words, the detection value of the acceleration sensor is used to evaluate the road surface profile.

[0017] 3 is a block diagram showing the main configuration of the storage device 40 according to this embodiment. The storage device 40 includes a computer having a calculation unit 410 such as a CPU, a storage unit 420 such as a ROM, a RAM, and other peripheral circuits (not shown) such as an I / O interface. The calculation unit 410 executes a program stored in the storage unit 420 to function as an information receiving unit 411.

[0018] The information receiving unit 411 receives driving information transmitted from the in-vehicle terminal 30 of each vehicle 20 traveling on a road. The driving information includes position information indicating the position of the vehicle 20, driving time information indicating the time when the vehicle 20 traveled through that position, and acceleration information indicating the acceleration of the vehicle 20. The acceleration information includes information on the lateral acceleration of the vehicle 20 detected by the acceleration sensor 33. The driving information also includes driving speed information indicating the driving speed of the vehicle 20. The driving speed information indicates the sensor value of the vehicle speed sensor 35, i.e., the measured value of the driving speed of the vehicle 20. The driving information also includes steering angle information indicating the steering angle of the steering wheel of the vehicle 20. The steering angle information indicates the sensor value of the steering angle sensor 34, i.e., the measured value of the steering angle of the vehicle 20. The vehicle ID accompanying the driving information makes it possible to identify the vehicle 20 that is the source of the driving information.

[0019] The information receiving unit 411 stores the travel information received from the multiple vehicles 20 (vehicle-mounted terminals 30) in chronological order in the storage unit 120. Hereinafter, the travel information stored in chronological order in the storage unit 120 will be referred to as time-series travel information.

[0020] 5 is a block diagram showing the main configuration of the road surface evaluation device 10 according to this embodiment. The road surface evaluation device 10 includes a computer having a calculation unit 110 such as a CPU, a storage unit 120 such as a ROM, a RAM, and other peripheral circuits (not shown) such as an I / O interface. The storage unit 120 stores map information including a road map and various information processed by the calculation unit 110.

[0021] The calculation unit 110 executes the programs stored in the storage unit 120 to function as an information acquisition unit 111 , an evaluation unit 112 , an output unit 113 , and a communication control unit 114 .

[0022] The information acquisition unit 111 acquires from the storage device 40 the travel information of the vehicles 20 corresponding to the period (hereinafter referred to as the evaluation period) and road (hereinafter referred to as the evaluation road) to be evaluated for road surface roughness. The evaluation period and the evaluation road are specified by an output instruction for a road surface profile, which will be described later. FIG. 5 is a diagram showing an example of a map of the road on which the vehicle 20 travels. In FIG. 5, the section (latitude Y to Z of national highway X) designated as the evaluation road is shaded with diagonal lines. In FIG. 5, the upward direction corresponds to the north direction, and the rightward direction corresponds to the east direction. When the evaluation road has multiple lanes on one side, the user may be able to specify the lanes to be evaluated for road surface roughness. The information acquisition unit 111 acquires map information including information on the evaluation road from the storage unit 120.

[0023] The evaluation unit 112 evaluates the amount of unevenness (depth or height) of the road surface of the road to be evaluated, that is, the road surface roughness, based on the travel information of the multiple vehicles 20 corresponding to the evaluation period and the evaluation road acquired by the information acquisition unit 111. More specifically, the evaluation unit 112 calculates a road surface roughness value indicating the degree of road surface roughness based on the lateral acceleration of the multiple vehicles 20 corresponding to the evaluation period acquired by the information acquisition unit 111. The road surface roughness value is, for example, a value expressed by IRI (International Roughness Index), which is an international index. Hereinafter, the road surface roughness value may be simply expressed as a roughness value.

[0024] FIG. 6 is a diagram showing an example of time-series travel information acquired by the road surface evaluation device 10 from the on-board terminal 30 of the vehicle 20 traveling on the evaluation target road (latitude Y to Z of national highway X) in FIG. 5. The horizontal axis in the diagram is the position (latitude) of the vehicle 20 in the traveling direction along the travel lane, and the vertical axis is the lateral acceleration of the vehicle 20. Characteristics D1, D2, . . . , Dn respectively represent the time-series travel information of the vehicles 20-1, 20-2, . . . , 20-n. In addition, by increasing the sampling period, the accuracy of the road surface roughness value calculated by the evaluation unit 112 can be improved, and the road surface profile can be evaluated with high accuracy. However, increasing the sampling period of the travel information (for example, 100 Hz) increases the processing load of the on-board terminal 30. Furthermore, the data amount of the travel information transmitted to the road surface evaluation device 10 is increased, which may put strain on the bandwidth of the communication network 2. Taking this into consideration, the evaluation unit 112 generates synthetic travel information of a second period (1×n Hz) by synthesizing the travel information of a first period (for example, 1 Hz) transmitted from the n vehicles 20, and calculates a road surface roughness value based on the synthetic travel information. Here, the generation of the synthetic travel information will be described with reference to FIG. 7.

[0025] FIG. 7 is a diagram showing an example of composite travel information generated based on travel information acquired from the vehicle-mounted terminals 30 of a plurality of vehicles 20 traveling on the road shown in FIG. 5. The composite travel information is information obtained by combining the acceleration information of each vehicle 20 based on the position information of each vehicle 20. The composite travel information shown in FIG. 7 is obtained by superimposing the values ​​of the vertical axis (lateral acceleration) of each vehicle 20 shown in FIG. 6 based on the horizontal axis (latitude). Since the vehicle speeds of each vehicle 20 and the points at which each vehicle 20 starts sampling are different from one another, even if the sampling period of the travel information of each vehicle 20 is the same, the timing at which the travel information is sampled is considered to be different for each vehicle 20. Therefore, by combining the travel information of 1 Hz sampled in n vehicles 20 as described above, travel information equivalent to 1×n Hz is obtained. The evaluation unit 112 evaluates the road surface roughness of the road on which each vehicle 20 is traveling based on the composite travel information obtained in this manner.

[0026] In general, the greater the amount of unevenness on the road surface, the greater the lateral acceleration of the vehicle 20, and there is a predetermined correlation between the road surface roughness value and the lateral acceleration. The evaluation unit 112 uses information indicating this correlation (hereinafter referred to as correlation data) to calculate the road surface roughness value corresponding to the vehicle position on the road from the lateral acceleration.

[0027] First, the evaluation unit 112 performs machine learning using previously measured road surface roughness values ​​and lateral acceleration as teacher data, and calculates the correlation between the road surface roughness value and the lateral acceleration. FIG. 8A and FIG. 8B are diagrams for explaining teacher data of road surface roughness values ​​and lateral acceleration, respectively. The vehicle V1 shown in FIG. 8A is a dedicated vehicle equipped with a measuring device MA for measuring road surface roughness. The measuring device MA measures the road surface roughness value of the road RD when the vehicle V1 is traveling on a predetermined road (measurement course, etc.) RD. The characteristic P1 in FIG. 8A indicates the road surface roughness value measured at this time, that is, the road surface roughness value used as teacher data.

[0028] Fig. 8B shows a state in which vehicle 20 in Fig. 1 travels on the same road RD as in Fig. 8A. A characteristic P2 in Fig. 8B shows the lateral acceleration detected by acceleration sensor 33 provided on vehicle 20 while vehicle 20 is traveling on a predetermined road RD, that is, the lateral acceleration used as teacher data.

[0029] The teacher data of the road surface roughness value and the lateral acceleration may be stored in the memory unit 120 of the road surface evaluation device 10, or may be stored in an external storage device. The evaluation unit 112 performs machine learning using the teacher data of the road surface roughness value and the lateral acceleration read from the memory unit 120 or the external storage device, and calculates the correlation between the road surface roughness value and the lateral acceleration. Note that the machine learning may be performed by adding the traveling speed, the longitudinal acceleration, and the steering angle as the teacher data.

[0030] The evaluation unit 112 calculates the road surface roughness value of the road to be evaluated based on the correlation between the calculated road surface roughness value and the lateral acceleration, and on the combined travel information corresponding to the road to be evaluated.

[0031] The output unit 113 outputs the roughness information of the road surface evaluated by the evaluation unit 112, that is, the road surface roughness value, in association with the road information acquired by the information acquisition unit 111. The information output at this time is called road surface profile information. When the output unit 113 receives an output instruction of the road surface profile from a terminal of a road management company or the like via the communication network 2, the output unit 113 outputs the road surface profile information to the terminal that sent the output instruction or a terminal of a predetermined output destination. The output instruction of the road surface profile may be input to the road surface evaluation device 10 via an operation unit (not shown) of the road surface evaluation device 10. The road surface profile information is information that can be displayed on a display device such as a display, and a user (for example, a road management company) can check the road surface profile by displaying the road surface profile information on a display of the user's terminal. The output unit 113 may output the road surface profile information to the storage unit 120. For example, the road surface profile information may be output so as to be mapped to map information stored in the storage unit 120.

[0032] However, as the number of vehicles 20 increases, the amount of data of the driving information increases, which may put strain on the memory area of ​​the storage device 40 (memory unit 420) and the bandwidth of the communication network 2. On the other hand, for sections where no major changes in the road surface due to sinkholes or the like are expected to occur, no emergency measures (road repairs, etc.) are required, so there is no need to present the detailed evaluation results of the road surface roughness to the user. Taking this into consideration, the evaluation unit 112 evaluates the road surface roughness as follows.

[0033] 9A, 9B, and 9C are diagrams showing an example of road surface profile information generated based on travel information acquired from a plurality of vehicles 20 traveling on a road to be evaluated (latitudes Y to Z of national highway X). The horizontal axis represents the position (latitude) of the vehicle 20 in the traveling direction along the travel lane, and the vertical axis represents the road surface roughness value.

[0034] FIG. 9A shows road surface profile information generated based on travel information acquired in a predetermined period T1. The characteristic P11 in the figure represents a road surface roughness value calculated based on the composite travel information obtained by synthesizing the travel information of the plurality of vehicles 20 acquired in the predetermined period T1. FIG. 9B shows road surface profile information generated based on travel information acquired in a predetermined period T2 after the predetermined period T1. The characteristic P21 in the figure represents a road surface roughness value calculated based on the composite travel information obtained by synthesizing the travel information of the plurality of vehicles 20 acquired in the predetermined period T2. FIG. 9C shows road surface profile information generated based on travel information acquired in a predetermined period T3 after the predetermined period T2. The characteristic P31 in the figure represents a road surface roughness value calculated based on the composite travel information obtained by synthesizing the travel information of the plurality of vehicles 20 acquired in the predetermined period T3. The road surface roughness values ​​R1, R2 (>R1), and R3 (>R2) respectively indicate the road surface roughness at the point A in the predetermined periods T1, T2, and T3.

[0035] 10A and 10B are diagrams for explaining the change in road surface roughness at point A. The horizontal axis represents time, and the vertical axis represents road surface roughness value. The black circle in Fig. 10A represents the road surface roughness value R1 at point A calculated based on the combined travel information corresponding to a predetermined period T1.

[0036] When calculating the road surface roughness value R2 of the point A in the predetermined period T2, the evaluation unit 112 first estimates the road surface roughness value of the point A in the predetermined period T2. The road surface roughness value estimated at this time is called the estimated roughness value. The white circle in FIG. 10A represents the estimated roughness value. The evaluation unit 112 acquires the road surface roughness value of the point A calculated using the combined travel information corresponding to the predetermined period T2 as the estimated roughness value ER2. Next, the evaluation unit 112 determines whether the magnitude (absolute value) of the change rate of the estimated roughness value ER2 with respect to the road surface roughness value R1 (hereinafter referred to as the roughness value change rate or simply the change rate) exceeds a predetermined threshold value. The region RG shaded with diagonal lines in FIG. 10A represents the range of the road surface roughness value in which the magnitude of the change rate with respect to the road surface roughness value R1 is equal to or less than the predetermined threshold value. As shown in FIG. 10A, the longer the elapsed time from the predetermined period T1, the larger the value set for the predetermined threshold value. The predetermined period T1 used as the reference when calculating the change rate is called the reference predetermined period.

[0037] In the example shown in Figure 10A, since the estimated roughness value ER2 is included within the region RG, the evaluation unit 112 determines that the magnitude of the rate of change of the estimated roughness value ER2 relative to the road surface roughness value R1 is less than or equal to a predetermined threshold value, and calculates the estimated roughness value ER2 as the road surface roughness value R2 at point A as is.

[0038] Similarly, when calculating the road surface roughness value R3 of the point A in the predetermined period T3, the evaluation unit 112 first estimates the road surface roughness value of the point A in the predetermined period T3. That is, the evaluation unit 112 calculates the estimated roughness value ER3 of the point A corresponding to the predetermined period T3. Then, the evaluation unit 112 determines whether the magnitude of the rate of change of the estimated roughness value ER3 relative to the road surface roughness value R1 exceeds a predetermined threshold value. In the example shown in FIG. 10A, the estimated roughness value ER3 of the point A corresponding to the predetermined period T3 is outside the region RG, so the evaluation unit 112 determines that the magnitude of the rate of change exceeds the predetermined threshold value.

[0039] When the magnitude of the change rate exceeds a predetermined threshold, it is assumed that the unevenness of the road surface has changed suddenly, and therefore, a road management company or the like must take measures such as repairs. Therefore, it is preferable that the sudden change in the unevenness of the road surface is detected with higher accuracy. Therefore, when the evaluation unit 112 determines that the magnitude of the change rate exceeds the predetermined threshold, it increases the travel information used in the calculation of the roughness value so as to improve the evaluation accuracy of the road surface roughness compared to when it is determined that the magnitude of the change rate is equal to or less than the predetermined threshold. Specifically, the evaluation unit 112 changes the start point or end point of the predetermined period T3 to extend the length of the predetermined period T3. As a result, the information acquisition unit 111 additionally acquires travel information of the vehicle 20 corresponding to the period extended by the evaluation unit 112 from the storage device 40. The evaluation unit 112 calculates the road surface roughness value R3 of the point A in the predetermined period T3 using the travel information additionally acquired by the information acquisition unit 111 in addition to the travel information used in the calculation of the estimated roughness value ER3.

[0040] FIG. 10B shows the estimated roughness value ER4 of the point A in a predetermined period T4 after the predetermined period T1. As in the example shown in FIG. 10B, even when the magnitude of the change rate of the estimated roughness value ER4 relative to the road surface roughness value R1 exceeds a predetermined threshold, if the estimated roughness value ER4 is below the region RG, that is, if the change rate is a negative value, it can be estimated that the road surface roughness has been improved by road repair or the like. In this case, the evaluation unit 112 does not acquire additional travel information. In addition, the evaluation unit 112 deletes the travel information corresponding to the point A stored in the storage device 40 (storage unit 420). Note that, regardless of the magnitude of the change rate, when the change rate is a negative value, that is, when the estimated roughness value ER4 is smaller than the road surface roughness value R1, the evaluation unit 112 may estimate that the road surface roughness has been improved by road repair or the like, and may not acquire additional travel information. In addition, the travel information corresponding to the point A stored in the storage device 40 may be deleted.

[0041] 11 is a flowchart showing an example of processing executed in the calculation unit 110 (CPU) of the road surface evaluation device 10 according to a predetermined program. The processing shown in this flowchart is repeated at a predetermined cycle while the road surface evaluation device 10 is running. First, in step S11, it is determined whether or not an instruction to output a road surface profile has been input (received).

[0042] The road surface profile output instruction includes section information that can identify the road to be evaluated. The section information includes information indicating the name of the road to be evaluated and the range of the section, such as "Road: National Highway No. X, Section: Latitude Y to Z". If the road has multiple lanes on one side, such as two lanes on one side, the section information may include information on the lanes to be evaluated, such as "Road: National Highway No. X, Lane: Right End, Section: Latitude Y to Z". Information other than latitude may be used to specify the road to be evaluated. For example, longitude may be used instead of latitude, or longitude may be used in addition to latitude. Furthermore, the distance from the start point of the section may be used. The road surface profile output instruction further includes period information that specifies the period to be evaluated. The period information includes information indicating the period to be evaluated, such as "one month from X month Y day". The period information also includes information specifying a reference specified period. A specified period that was previously set as a period to be evaluated is specified as the reference specified period.

[0043] If the result in step S11 is negative, the process is terminated. If the result in step S11 is positive, in step S12, map information is read from the storage unit 120, and road information included in the map information is acquired. In step S13, travel information of the vehicle 20 is acquired from the storage unit 120. More specifically, based on the section information and period information included in the output instruction of the road surface profile and the road information acquired in step S12, travel information corresponding to the evaluation target road specified by the section information and corresponding to the evaluation target period specified by the period information is read from the storage unit 120. At this time, if there are multiple vehicles 20 that have traveled on the evaluation target road, travel information corresponding to each of the multiple vehicles 20 is acquired. In addition, when the section information included in the output instruction of the road surface profile includes information on the lane to be evaluated, travel information including position information corresponding to the lane is read from the storage unit 120.

[0044] In step S14, composite travel information is generated based on the travel information read from the storage unit 120 in step S13. In step S15, road surface roughness is estimated based on the composite travel information generated in step S14. More specifically, a road surface roughness value is calculated based on the composite travel information generated in step S14, and the road surface roughness value is acquired as an estimated roughness value. In step S16, it is determined whether or not a point where the magnitude of the change rate of the estimated roughness value with respect to the road surface roughness value corresponding to the reference predetermined period exceeds a predetermined threshold value exists in the evaluation target road. If the result in step S16 is negative, the process proceeds to step S18. If the result in step S16 is positive, in step S17, the evaluation target period is extended, and travel information of the vehicle 20 corresponding to the extended period and corresponding to a point where the magnitude of the change rate exceeds a predetermined threshold value is additionally acquired from the storage unit 40. Then, composite travel information is generated based on the travel information read from the storage unit 120 in step S13 and the additionally acquired travel information.

[0045] In step S18, the road surface roughness is evaluated. Specifically, in step S18, which is executed after step S16 is negative, the estimated roughness value acquired in step S15 is used as is for evaluating the road surface roughness. On the other hand, in step S18, which is executed after step S17, the road surface roughness value is calculated based on the combined travel information generated in step S17.

[0046] In step S19, information is generated in which the road surface roughness value calculated in step S18 is associated with the road information acquired in step S12, i.e., road surface profile information. In step S20, the road surface profile information generated in step S19 is output. This allows the road surface profile information to be displayed on a display device such as a display, allowing the user to check the road surface profile information. When the evaluation period is extended in step S17, the road surface profile information may include information (such as text information) indicating that the evaluation period has been extended and the evaluation period after the extension. In addition, the road surface profile information may include information indicating a point where the magnitude of the rate of change is equal to or greater than a predetermined threshold, for example, display information such that the road surface roughness value corresponding to that point is displayed in a different color from the road surface roughness values ​​corresponding to other points.

[0047] According to the embodiment of the present invention, the following advantageous effects can be obtained. (1) The road surface evaluation device 10 includes an information acquisition unit 111 that acquires driving information of each of the multiple vehicles 20, including acceleration information indicating the acceleration of the multiple vehicles 20, and acquires map information including information of the roads on which the multiple vehicles 20 have traveled; and an output unit 113 that calculates a roughness value indicating the roughness of the road surface of the road corresponding to a specified period based on the driving information of the multiple vehicles 20 that have traveled on the road during a specified period acquired by the information acquisition unit 111, and outputs roughness information including the calculated roughness value in correspondence with the road information acquired by the information acquisition unit 111. When the evaluation unit 112 calculates a roughness value corresponding to a second predetermined period (predetermined periods T2, T3, T4) subsequent to the first predetermined period (reference predetermined period T1), the information acquisition unit 111 estimates whether the rate of change of the roughness value corresponding to the second predetermined period with respect to the roughness value corresponding to the first predetermined period calculated by the evaluation unit 112 exceeds a predetermined threshold, and when it estimates that the rate of change exceeds the predetermined threshold, it acquires more driving information to be used for calculating the roughness value corresponding to the second predetermined period than when it estimates that the rate of change is equal to or less than the predetermined threshold. When it estimates that the magnitude of the rate of change exceeds the predetermined threshold, the information acquisition unit 111 changes the start or end point of the second predetermined period to extend the second predetermined period, and acquires driving information of a plurality of vehicles corresponding to the extended second predetermined period. As a result, the road surface roughness is evaluated based on more driving information for a portion where the road surface roughness has changed more than expected, so that the evaluation accuracy of the road surface roughness for the road surface change portion can be improved. In addition, compared to improving the evaluation accuracy of road surface roughness for the entire road, the amount of data of the driving information used for evaluating the road surface roughness can be reduced, which reduces the load on the device and communication infrastructure. Therefore, the road surface roughness can be evaluated efficiently and accurately.

[0048] (2) The longer the interval between the first and second predetermined periods, the larger the predetermined threshold value is set. This allows highly accurate evaluation of road surface roughness to be performed only on road surface changes that require urgent repair, such as depressions, so as to exclude road surface changes caused by aging. As a result, the amount of data of the driving information used to evaluate the road surface roughness can be further reduced.

[0049] (3) The information acquisition unit 111 acquires driving information of multiple vehicles corresponding to a predetermined period from the storage device 40 that stores driving information of multiple vehicles 20. When the rate of change exceeds a predetermined threshold and the roughness value corresponding to the second predetermined period is smaller than the roughness value corresponding to the first predetermined period, the information acquisition unit 111 deletes the roughness information corresponding to the first predetermined period from the storage device 40. This makes it possible to reduce the amount of data of the driving information stored in the storage device 40.

[0050] In the above embodiment, when the information acquisition unit 111 as a travel information acquisition unit estimates that the magnitude of the change rate exceeds the predetermined threshold, the information acquisition unit 111 changes the start point or end point of the second predetermined period to extend the second predetermined period, and additionally acquires travel information of multiple vehicles corresponding to the extended second predetermined period. Then, the evaluation unit 112 as a calculation unit calculates the road surface roughness value corresponding to the second predetermined period using the additionally acquired travel information. However, when the travel information acquisition unit estimates that the magnitude of the change rate exceeds the predetermined threshold, in addition to the travel information of the multiple vehicles 20 corresponding to the second predetermined period, the information acquisition unit may additionally acquire travel information of other multiple vehicles 20 corresponding to the second predetermined period.

[0051] Furthermore, in the above embodiment, the information acquisition unit 111 as a map information acquisition unit acquires map information including information on roads on which the vehicle 20 travels from the storage unit 120. However, the map information acquisition unit may acquire map information including information on roads on which the vehicle 20 travels from an external server device or the like.

[0052] The above description is merely an example, and the present invention is not limited to the above-mentioned embodiment and modifications, as long as the features of the present invention are not impaired. One or more of the above-mentioned embodiment and modifications can be arbitrarily combined, and modifications can also be combined with each other. [Explanation of symbols]

[0053] 10 Road surface evaluation device, 20, 20-1 to 20-n Vehicles, 30 Vehicle-mounted terminal, 40 Travel information storage device, 110 Calculation unit, 111 Information acquisition unit, 112 Evaluation unit, 113 Output unit, 120 Storage unit

Claims

1. A travel information acquisition unit that acquires travel information of each of the plurality of vehicles, the travel information including acceleration information indicating the acceleration of the plurality of vehicles; a map information acquisition unit that acquires map information including information on roads on which the plurality of vehicles have traveled; a calculation unit that calculates a roughness value indicating a roughness of a road surface of the road corresponding to a predetermined period based on the travel information of the plurality of vehicles that have traveled on the road during the predetermined period acquired by the travel information acquisition unit; and an output unit that outputs roughness information including the roughness value calculated by the calculation unit in association with the information on the road acquired by the map information acquisition unit, The road surface evaluation device is characterized in that, when the calculation unit calculates the roughness value corresponding to a second specified period that is later than a first specified period, the driving information acquisition unit estimates whether a rate of change of the roughness value corresponding to the second specified period relative to the roughness value corresponding to the first specified period calculated by the calculation unit exceeds a specified threshold, and when it estimates that the rate of change exceeds the specified threshold, it acquires more of the driving information to be used for calculating the roughness value corresponding to the second specified period than when it estimates that the rate of change is equal to or less than the specified threshold.

2. The road surface evaluation device according to claim 1, The road surface evaluation device is characterized in that, when the driving information acquisition unit estimates that the magnitude of the change rate exceeds the specified threshold, it changes the start point of the second specified period to extend the second specified period, and acquires the driving information of the multiple vehicles corresponding to the extended second specified period.

3. The road surface evaluation device according to claim 1, The road surface evaluation device is characterized in that, when the driving information acquisition unit estimates that the magnitude of the change rate exceeds the specified threshold, it changes the end point of the second specified period to extend the second specified period, and acquires the driving information of the multiple vehicles corresponding to the extended second specified period.

4. The road surface evaluation device according to claim 1, The road surface evaluation device is characterized in that, when the driving information acquisition unit estimates that the magnitude of the rate of change exceeds the specified threshold, it acquires, in addition to the driving information of the multiple vehicles corresponding to the second specified period, the driving information of other vehicles other than the multiple vehicles corresponding to the second specified period.

5. The road surface evaluation device according to claim 1, A road surface evaluation device, characterized in that the longer the interval between the first predetermined period and the second predetermined period, the larger the value set for the predetermined threshold value.

6. The road surface evaluation device according to any one of claims 1 to 5, the travel information acquisition unit acquires the travel information of the plurality of vehicles corresponding to the predetermined period from a storage device that stores the travel information of the plurality of vehicles; Further, the road surface evaluation device is characterized in that the driving information acquisition unit deletes the roughness information corresponding to the first specified period from the storage device when the rate of change exceeds the specified threshold and the roughness value corresponding to the second specified period is smaller than the roughness value corresponding to the first specified period.

Images