Road surface state estimating method

Abstract

To provide a road surface state estimating method capable of grasping a change in road surface states of a plurality of points.SOLUTION: A road surface state estimating method includes the steps of: registering vehicle information acquired from a plurality of vehicles in an information processing device (step S210); comparing travel information acquired for the same point with another travel information registered in the information processing device to extract a change in acceleration information when passing the point (step S230); and if the change in the acceleration information is extracted (step S240: YES), determining whether or not the change in the acceleration information is caused by a driving operation by a driver (step S250). The above estimating method determines whether or not the change in acceleration information is caused by a driving operation by a driver based on the travel information and then, if it is determined that the change in acceleration information is not caused by the driving operation by the driver, estimates that a change in a road surface state has occurred.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This invention relates to a method for estimating road surface conditions.

Background Art

[0002] Patent Document 1 discloses a road surface condition determination method for determining the condition of the road surface on which a four-wheeled vehicle is traveling. In this road surface condition determination method, the condition of the road surface on which the four-wheeled vehicle is traveling is determined from the relationship between the wheel speed rotation information of the driving wheels of the four-wheeled vehicle during travel and the acceleration information.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above road surface condition determination method can only grasp the road surface condition at the point where the own vehicle is traveling.

Means for Solving the Problems

[0005] The method for estimating the road surface condition of the present invention estimates the condition of the road surface on which the vehicle is traveling. An information processing device capable of communicating with a plurality of vehicles acquires vehicle information including running information and position information, which includes acceleration information and driving operation information during running, from the plurality of vehicles and registers it in a database. The information processing device extracts a change in acceleration information when passing through a point by comparing the acquired running information for the same point with other running information registered in the database. When a change in acceleration information is extracted, the information processing device determines whether the change in acceleration information is due to a driving operation by the driver based on the running information at the point where the change in acceleration information is extracted. When it is determined that the change in acceleration information is due to a driving operation by the driver, the information processing device estimates that there is no change in the road surface condition at the point. When it is determined that the change in acceleration information is not due to a driving operation by the driver, the information processing device estimates that there is a change in the road surface condition at the point.

Effect of the Invention

[0006] The above method for estimating the road surface condition can grasp changes in the road surface condition at a plurality of points.

Brief Description of the Drawings

[0007]

Figure 1

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Mode for Carrying Out the Invention

[0008] Hereinafter, an embodiment of the method for estimating the road surface condition will be described with reference to FIGS. 1 to 7. <Configuration of Vehicle 10 and Information Processing Device 20> FIG. 1 schematically shows the configuration of a vehicle 10 and an information processing device 20 for implementing the method for estimating the road surface condition according to the embodiment.

[0009] As shown in FIG. 1, the vehicle 10 includes a control device 11, a position information acquisition unit 12, and a communication device 13. The control device 11 performs overall control of the vehicle 10, such as driving state control for controlling the engine, transmission, brakes, etc. of the vehicle 10, and communication control for controlling communication between the vehicle 10 and the outside. The position information acquisition unit 12 receives radio waves transmitted from satellites and acquires the position information of the vehicle 10. The communication device 13 can communicate with external devices of the vehicle 10, can transmit vehicle information to the external devices, and can receive various information regarding weather, road surface condition, etc. from the external devices. The vehicle information consists of driving information including acceleration information and driving operation information during driving, and position information acquired by the position information acquisition unit 12. The other vehicles 100, 200 are each configured to have the same configuration as the vehicle 10.

[0010] The information processing device 20 can communicate with a plurality of vehicles such as, for example, the vehicle 10, other vehicles 100, 200, etc. As shown in FIG. 1, the information processing device 20 includes a vehicle information receiver 21, a database 22, and a processing device 23. The vehicle information receiver 21 acquires vehicle information from a plurality of vehicles 10. The database 22 registers information such as weather information and vehicle information acquired by the vehicle information receiver 21. The processing device 23 estimates a change in the road surface condition by comparing the driving information acquired by the vehicle information receiver 21 with other driving information registered in the database 22. The information processing device 20 can be configured using a plurality of computers. For example, the information processing device 20 can be configured by a plurality of server devices.

[0011] <Processing by Vehicle 10> Referring to FIG. 2, the flow of processing executed by the vehicle 10 to implement the method for estimating the road surface condition will be described. This series of processing may start when the vehicle 10 starts to drive, or may start in response to an operation by the driver to start the estimation of the road surface condition. The series of processing shown in FIG. 2 is repeatedly executed by the control device 11.

[0012] As shown in FIG. 2, when starting this series of processing, the control device 11 executes the processing of step S100 to acquire vehicle information. The vehicle 10 accumulates the acquired vehicle information. When the vehicle information is acquired in step S100, the control device 11 advances the processing to step S110 to determine whether it is the transmission timing. The transmission timing is the timing to transmit information to the information processing device 20. The transmission timing arrives at a predetermined time interval. The transmission timing can also be set in advance by the user.

[0013] In step S110, if it is determined that it is the transmission timing (step S110: YES), the control device 11 advances the processing to step S120 to transmit the vehicle information to the information processing device 20. Then, the series of processing ends.

[0014] On the other hand, if it is determined in step S110 that the transmission timing has not arrived (step S110: NO), the control device 11 ends the process. In this way, every time the transmission timing arrives, the control device 11 of the vehicle 10 transmits the accumulated vehicle information to the information processing device 20.

[0015] <Processing by the information processing device 20> Referring to FIG. 3, the flow of the process executed by the information processing device 20 to implement the method for estimating the road surface condition will be described. The series of processes shown in FIG. 3 are repeatedly executed by the information processing device 20.

[0016] When starting this series of processes, the information processing device 20 executes the process of step S200 to determine whether vehicle information has been received. If it is determined in step S200 that vehicle information has been received (step S200: YES), the information processing device 20 advances the process to step S210 and registers the received vehicle information in the database 22. On the other hand, if it is determined in step S200 that vehicle information has not been received (step S200: NO), the information processing device 20 ends the process.

[0017] Next, the information processing apparatus 20 advances the process to step S220 and determines whether the point where the vehicle 10 is traveling during driving is a preset target point based on the position information included in the vehicle information. If it is determined in step S220 that it is the target point (step S220: YES), the information processing apparatus 20 advances the process to step S230. In step S230, the information processing apparatus 20 compares the driving information obtained from the vehicle information received in step S200 for the same target point with other driving information registered in the database 22, and extracts the change in the acceleration information when passing through the target point. The driving information registered in the database 22 is, for example, driving information in a normal state where no special change in the road surface condition such as freezing, waterlogging, or accumulation of fallen leaves has occurred. The driving information registered as driving information in the normal state is the average driving information of many vehicles and does not include driving information in which a special driving operation has been performed or the driving state deviates from that of many vehicles. Then, the information processing apparatus 20 advances the process to step S240. On the other hand, if it is determined in step S220 that it is not the target point (step S220: NO), the information processing apparatus 20 ends the process.

[0018] In step S240, based on the result of comparing the driving information in step S230, it is determined whether the change in the acceleration information has been extracted. If it is determined in step S240 that the change in the acceleration information has been extracted (step S240: YES), the information processing apparatus 20 advances the process to step S250. Then, in step S250, the information processing apparatus 20 determines whether the change in the acceleration information is due to the driving operation by the driver and estimates the road surface condition. That is, in step S250, if it is determined that the change in the acceleration information is due to the driving operation by the driver, the information processing apparatus 20 estimates that no change in the road surface condition has occurred at the target point and ends the process. On the other hand, if it is determined in step S250 that the change in the acceleration information is not due to the driving operation by the driver, the information processing apparatus 20 estimates that a change in the road surface condition has occurred at the target point and ends the process.

[0019] On the other hand, when it is determined in step S240 that the change in the acceleration information has not been extracted (step S240: NO), the information processing device 20 ends the series of processes. As described above, the flow of the series of processes executed by the information processing device 20 has been explained. Hereinafter, preferred examples of each process will be explained.

[0020] · In step S230 of extracting the change in the acceleration information, the information processing device 20 compares the driving information in which the vehicle types are common. · In step S210 of registering the vehicle information in the database 22, the information processing device 20 registers the acquired vehicle information in the database 22 in association with the weather information. In step S250 of estimating the road surface condition, when it is estimated that a change in the road surface condition has occurred, the information processing device 20 estimates the road surface condition based on the weather information.

[0021] · In step S250 of estimating the road surface condition, when it is estimated that a change in the road surface condition has occurred, the information processing device 20 also refers to the position information to estimate the road surface condition. Hereinafter, with reference to FIGS. 4 to 7, an example of estimating that the road surface is waterlogged using the road surface condition estimation method will be described. FIG. 4 shows, as an example, a point A where waterlogging is likely to occur. As shown in FIG. 4, at point A, the road surface is inclined. At point A, the gradient of the road surface changes from a downward gradient to an upward gradient in the middle. The part where the gradient changes from a downward gradient to an upward gradient is the lowest, and this part is likely to be waterlogged.

[0022] FIG. 5 shows the driving information when passing through point A in a normal state where waterlogging has not occurred. In this case, the accelerator operation is maintained as "on" as shown in FIG. 5(b), and the brake operation remains "off" without changing to "on" as shown in FIG. 5(c). Therefore, as shown in FIG. 5(a), the acceleration changes according to the road surface gradient at point A. That is, during the downward gradient, the acceleration gradually increases. After the road surface gradient becomes an upward gradient at time T2, the acceleration gradually decreases.

[0023] FIG. 6 shows the driving information when the driver decelerates and passes the vehicle 10 at point A in a normal state where there is no waterlogging, which is different from many vehicles. In this case, as shown in FIG. 6(b), the accelerator operation changes from "on" to "off" at time T1 before time T2 when the road surface gradient becomes an uphill gradient. As shown in FIG. 6(c), the brake operation changes from "off" to "on" at time T1. As shown in FIG. 6(b), the accelerator operation is maintained at "off" until time T3 after time T2. The accelerator operation is "on" at time T3. In this case, as shown in FIG. 6(a), the acceleration decreases not only due to the change in the road surface gradient at time T2 but also due to the "on" to "off" brake operation at time T1. Further, it increases due to the "off" to "on" accelerator operation at time T3. Therefore, the information processing device 20 extracts the change in the acceleration information shown in FIG. 6(a) in comparison with the driving information shown in FIG. 5.

[0024] In the case of the example shown in FIG. 6, although the change in the acceleration information is extracted, the driving operation by the driver is being performed. Therefore, the information processing device 20 determines that the change in the acceleration information is due to the driving operation by the driver. In this case, the information processing device 20 estimates that there is no change in the road surface condition.

[0025] FIG. 7 shows the driving information when passing through point A where there is waterlogging. In this case, as shown in FIGS. 7(b) and 7(c), the accelerator operation and the brake operation are maintained without changing in the same manner as FIGS. 5(b) and 5(c), respectively. However, in this case, as shown in FIG. 7(a), similar to FIG. 6(a), the acceleration decreases at time T1 and increases at time T3. This is because the vehicle 10 enters the waterlogged area at time T1 and the speed decreases, while it exits the waterlogged area at time T3 and the speed increases. The information processing device 20 extracts the change in the acceleration information shown in FIG. 7(a) in comparison with the driving information shown in FIG. 5.

[0026] In the case of the example shown in FIG. 7, although no driving operation is being performed by the driver, a change in the acceleration information is being extracted. Therefore, the information processing device 20 determines that the change in the acceleration information is not due to the driver's driving operation. In this case, the information processing device 20 estimates that a change has occurred in the road surface condition.

[0027] The information processing device 20 also estimates the road surface condition with reference to the weather information and the position information. The information processing device 20 can grasp that the point where the vehicle 10 has passed based on the position information is point A and that it is a terrain where waterlogging is likely to occur. The information processing device 20 can grasp that it is raining or that it has just rained based on the weather information. Therefore, the information processing device 20 can estimate that the road surface condition at point A is waterlogging by referring to the position information and the weather information.

[0028] As described above, with reference to FIGS. 4 to 7, an example of estimating a change in the road surface condition due to waterlogging has been described. The method for estimating the road surface condition according to the present embodiment can similarly estimate a change in the road surface condition due to freezing or the accumulation of fallen leaves.

[0029] For example, when the vehicle 10 is cruising at a constant speed at a flat point, the opening of the accelerator operation is maintained constant and no braking operation is performed. Therefore, the acceleration of the vehicle 10 is maintained without change.

[0030] When a part of the road surface is frozen at the above-mentioned flat point, even if no driving operation is being performed, when the vehicle 10 enters the frozen part, the wheels slip and the acceleration temporarily increases. And when it exits the frozen part, the wheels grip the road surface and the acceleration temporarily decreases.

[0031] On the other hand, even if the road surface is not frozen, when the vehicle 10 passes through the above-mentioned flat road surface, a change in acceleration similar to that in the case of freezing may occur due to the driver's accelerator operation or braking operation.

[0032] Therefore, the information processing device 20 excludes such changes in acceleration information that are due to the driving operations by the driver. Further, the information processing device 20 can estimate that freezing has occurred at the location by determining from the climate information and the position information that there is a high possibility of road surface freezing.

[0033] Even when fallen leaves are deposited on the road surface, wheel slip may occur in the same way as when the road surface is frozen. The climate information can be used to grasp information on the season, date and time, and weather. Thereby, it is possible to grasp from the climate information whether it is a state where freezing is likely to occur or a state where deposition of fallen leaves is likely to occur. From the position information, it is possible to grasp whether the location where the vehicle 10 is traveling is a location where freezing is likely to occur or a location where deposition of fallen leaves is likely to occur. Therefore, the information processing device 20 can estimate that the state of the road surface is deposition of fallen leaves by using the climate information and the position information together.

[0034] <Actions of this Embodiment> The information processing device 20 estimates the state of the road surface on which the vehicle 10 is traveling. The information processing device 20 capable of communicating with a plurality of vehicles 10 acquires vehicle information including running information including acceleration information and driving operation information during running and position information from the plurality of vehicles 10 and registers it in the database 22. The information processing device 20 extracts a change in acceleration information when passing through a location by comparing the acquired running information about the same location with other running information registered in the database 22. When a change in acceleration information is extracted, the information processing device 20 determines whether the change in acceleration information is due to the driving operation by the driver based on the running information at the location where the change in acceleration information is extracted. When it is determined that the change in acceleration information is due to the driving operation by the driver, the information processing device 20 estimates that there is no change in the road surface state at the location. When it is determined that the change in acceleration information is not due to the driving operation by the driver, the information processing device 20 estimates that there is a change in the road surface state at the location.

[0035] The information processing device 20 provides information on the road surface conditions estimated for each target location. For example, when it is estimated that a change in the road surface condition has occurred at a target location on the route being guided in a navigation system, the estimated information on the road surface condition is displayed or read aloud in voice to notify the driver. Even if the information processing device 20 cannot identify the road surface condition, when it is estimated that a change has occurred in the road surface condition, it notifies that a change has occurred in the road surface condition.

[0036] In addition, the estimated information on the road surface condition of each target location may be publicly disclosed so that the estimated results of the road surface conditions of each target location are displayed on a website together with a map. As a result, the user can grasp in advance the road surface conditions of a plurality of locations, not limited to the location where the user is driving.

[0037] <Effects of the present embodiment> (1) When the road surface condition changes, wheel slip or the like occurs, and a change different from normal appears in the acceleration information of the vehicle 10. If the road surface condition has not changed, the acceleration information when passing the same point should be of the same degree. However, even if the road surface condition has not changed, a change in the acceleration information may be extracted due to the driving operation by the driver. The above-described method for estimating the road surface condition determines whether the change in the acceleration information is due to the driving operation by the driver based on the driving information. And when it is determined that the change in the acceleration information is not due to the driving operation by the driver, it is estimated that a change in the road surface condition has occurred. Therefore, the above-described estimation method can suppress erroneously estimating that the road surface condition has changed based on the change in the acceleration information extracted due to the driving operation by the driver.

[0038] In addition, the above estimation method registers vehicle information acquired from a plurality of vehicles 10, 100, 200 in the information processing device 20. Then, the above estimation method uses information including driving information acquired from other vehicles 100, 200 registered by the information processing device 20 to estimate that a change has occurred in the road surface condition. Therefore, the above method for estimating the road surface condition can grasp the changes in the road surface condition at a plurality of locations.

[0039] (2) When extracting the change in acceleration information, the information processing device 20 compares driving information with a common vehicle type. If there is no change in the road surface condition for the plurality of vehicles 10, the driving information of vehicles with a common vehicle type will be particularly similar. The above method for estimating the road surface condition compares driving information with a common vehicle type. Therefore, it is possible to suppress the difference in driving information due to the difference in vehicle type from affecting the estimation result. Therefore, the above estimation method can accurately grasp the change in the road surface condition.

[0040] (3) When registering the vehicle information in the database 22, the information processing device 20 associates the acquired vehicle information with the weather information and registers it in the database 22. When it is estimated that a change has occurred in the road surface condition, the information processing device 20 estimates the road surface condition based on the weather information.

[0041] For example, in the case of heavy rain, the change in the road surface condition is likely to be due to waterlogging. In the case of heavy snow, the change in the road surface condition is likely to be freezing of the road surface. In the case of the season of fallen leaves, the change in the road surface condition is likely to be the accumulation of fallen leaves on the road. By referring to the weather information as in the above estimation method, it is possible to estimate road surface conditions such as waterlogging, freezing, and accumulation of fallen leaves.

[0042] (4) When it is estimated that a change has occurred in the road surface condition, the information processing device 20 also refers to the position information to estimate the road surface condition. There are terrains and regions where specific road surface conditions are likely to occur, such as places where waterlogging is likely to occur, places where the road surface is likely to freeze, and places where fallen leaves are likely to accumulate. The above estimation method estimates the road surface condition with reference to the position information. Therefore, the road surface condition can be estimated more accurately.

[0043] (5) The information processing device 20 estimates whether or not a change in the road surface condition has occurred only for a preset target point. For example, it may be known in advance where waterlogging is likely to occur. At a point where there are many deciduous trees planted in the vicinity, fallen leaves are likely to accumulate. Areas where snow is likely to fall in winter can also be specified in advance. At points such as bridges and overpasses where the road surface temperature is likely to drop, the road surface is likely to freeze. In this way, points where changes in the road surface condition are likely to occur can be specified in advance. The above road surface condition estimation method estimates whether or not a change in the road surface condition has occurred only for a preset target point. Therefore, the estimation can be performed by narrowing down to points where changes in the road surface condition can be estimated, and the reliability of the estimation result can be improved.

[0044] <Modification Example> This embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range.

[0045] · In step S230 of extracting the change in acceleration information, the information processing device 20 compares the driving information common to the vehicle types. However, the information processing device 20 may compare the driving information of a plurality of similar vehicle types to extract the change in acceleration information. The information processing device 20 may compare the driving information of different vehicle types without considering the vehicle type to extract the change in acceleration information.

[0046] · In this embodiment, the road surface conditions to be estimated are described by taking waterlogging, freezing, and accumulation of fallen leaves as examples. However, the road surface conditions estimated by the information processing device 20 may include other road surface conditions where, for example, wheel slip occurs and the acceleration information of the vehicle 10 shows a change different from normal.

[0047] · When comparing the acquired running information with other running information registered in the database 22, it is not always necessary to compare the running information in the normal state. In short, the information processing device 20 may compare it with the running information when it was previously estimated that the road surface state was a specific state. For example, the information processing device 20 may compare it with the running information when it was previously estimated that waterlogging occurred, and when the acquired running information is similar, it may be estimated that waterlogging has occurred.

Explanation of Signs

[0048] 10… Vehicle 11… Control device 12… Position information acquisition device 13… Communication device 20… Information processing device 21… Vehicle information receiver 22… Database 23… Processing device 100, 200… Other vehicles

Claims

1. A method for estimating the state of a road surface on which a vehicle is traveling, comprising: an information processing device capable of communicating with a plurality of vehicles acquires vehicle information including traveling information and position information, the traveling information including acceleration information and driving operation information during traveling, from the plurality of vehicles, and registers the vehicle information in a database; the information processing device extracts a change in the acceleration information when passing through the point by comparing the acquired traveling information about the same point with the other traveling information registered in the database; when the change in the acceleration information is extracted, the information processing device determines whether the change in the acceleration information is due to a driving operation by a driver based on the traveling information at the point where the change in the acceleration information is extracted, and when it is determined that the change in the acceleration information is due to a driving operation by a driver, estimates that there is no change in the road surface state at the point, and when it is determined that the change in the acceleration information is not due to a driving operation by a driver, estimates that there is a change in the road surface state at the point. A method for estimating the state of a road surface.

2. In the step of extracting the change in the acceleration information, the information processing device compares the traveling information in which the vehicle types are common. The method for estimating the state of a road surface according to Claim 1.

3. In the step of registering the vehicle information in the database, the information processing device registers the acquired vehicle information in the database in association with weather information; when it is estimated that there is a change in the road surface state, the information processing device estimates the road surface state based on the weather information. The method for estimating the state of a road surface according to Claim 1.

4. when it is estimated that there is a change in the road surface state, the information processing device also refers to the position information to estimate the road surface state. The method for estimating the state of a road surface according to Claim 3.

5. Estimate whether there is a change in the road surface state only for a preset target point. The method for estimating the state of a road surface according to Claim 1.

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