Information processing device, vehicle, information processing system, information processing method, and program

Abstract

To enable estimation of road surface condition with high accuracy.SOLUTION: A brake ECU executes processing including the steps of: acquiring data (S100); if a predetermined condition holds (YES in S102), there is variation in a left front wheel (YES in S104), there is no variation in a right front wheel (NO in S106), a left rear wheel varies in a time dependent on a vehicle speed and WB (YES in S108), and the variation of the left wheel continues (NO in S110), determining that there is singly occurring roughness on a road surface under the left wheel (S116); if the variation of the left wheel continues (YES in S110), and it is determined there is roughness that is continuous laterally (YES in S112), determining that there is roughness on the road surface that is continuous across both wheels (S114); and if it is determined that there is no roughness that is continuous laterally (NO in S112), determining that there is continuous roughness on the road surface under the left wheel.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a technique for estimating road surface conditions using information obtained from a vehicle. [Background technology]

[0002] There is a known technology for estimating road surface conditions using basic data including vibration data collected by a vehicle. For example, JP 2018-205970 A (Patent Document 1) discloses a technology for analyzing vibration data when the vehicle speed at the detection position of the vibration data is equal to or greater than a predetermined value, and excluding the vibration data from the analysis when the vehicle speed is less than the predetermined value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-205970 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned Patent Document 1 discloses a technology for separating out inappropriate data by selecting whether or not to include the data in the analysis depending on the vehicle speed. However, further improvements are required to estimate road surface conditions with high accuracy.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide an information processing device, a vehicle, an information processing system, an information processing method, and a program capable of estimating road surface conditions with high accuracy. [Means for solving the problem]

[0006] An information processing device according to an aspect of the present disclosure is an information processing device that acquires information about a road surface on which a vehicle runs. This information processing device includes a detection unit that detects fluctuations in rotation speed of each wheel of the vehicle, and a determination unit that determines the condition of the road surface using a determination result of whether fluctuations in rotation speed of left and right wheels of the vehicle are synchronized or not, and a time difference between a time point when fluctuations in rotation speed of a first wheel on the front side of the vehicle occur and a time point when fluctuations in rotation speed of a second wheel on the rear side of the vehicle occur.

[0007] In this way, fluctuations in the rotational speed of each wheel caused by steps or unevenness on the road surface are synchronized or linked between the wheels, so the road surface conditions can be determined with high accuracy by using the determination result of whether the fluctuations in the rotational speed of the left and right wheels of the vehicle are synchronized or not and the time difference.

[0008] In one embodiment, the determination unit determines that an uneven portion is formed on the road surface at a position on the trajectory of the first wheel and the second wheel when the time difference corresponds to a movement period in which the vehicle moves by the wheelbase of the vehicle.

[0009] In this way, when the time difference corresponds to the travel period during which the vehicle moves by the wheelbase of the vehicle, the fluctuations in the rotational speed of the first wheel and the fluctuations in the rotational speed of the second wheel occur in conjunction with each other due to the passage of an uneven portion formed on the road surface, so it can be accurately determined that an uneven portion has been formed on the road surface at a position on the trajectory of the first wheel and the second wheel.

[0010] In addition, in one embodiment, if the fluctuation in the rotational speeds of the first wheel and the second wheel continues, the judgment unit judges that either a ridge or a groove, in which the unevenness is continuous along a trajectory, has been formed on the road surface.

[0011] In this way, if the fluctuation in the rotational speed of the first wheel and the second wheel continues, a continuous bump or groove will be formed along the trajectory of the unevenness, making it possible to accurately determine whether a bump or groove has been formed on the road surface.

[0012] In yet another embodiment, the judgment unit judges that a step crossing the road surface has formed on the road surface when the fluctuations in the rotational speed of the left and right wheels are synchronized and the time difference corresponds to the travel period during which the vehicle moves an amount equal to the wheelbase of the vehicle.

[0013] In this way, if the left and right wheels are synchronized and the time difference corresponds to the period of travel in which the vehicle moves by the vehicle's wheelbase, the left and right wheels will have overcome a step crossing the road surface, making it possible to accurately determine whether or not a step has formed on the road surface.

[0014] Furthermore, in one embodiment, the judgment unit judges that an undulation consisting of multiple steps has formed on the road surface when it is judged multiple times that the fluctuations in the rotational speeds of the left and right wheels are synchronized and that the time difference corresponds to the travel period.

[0015] In this way, if it is determined multiple times that a step has formed on the road surface, it means that multiple steps have formed, so it can be determined with high accuracy that an undulation made up of multiple steps has formed on the road surface.

[0016] In yet another embodiment, the information processing device further includes a transmission unit that transmits the road surface condition determined by the determination unit and position information of the road surface to an external server.

[0017] In this way, by making it possible to transmit information about road surface conditions to an external server, it is possible to improve the usefulness of the information about road surface conditions.

[0018] A vehicle according to another aspect of the present disclosure is a vehicle equipped with an information processing device that acquires information about a road surface on which the vehicle travels. The information processing device includes a detection unit that detects fluctuations in rotation speed of each wheel of the vehicle, and a determination unit that determines the condition of the road surface using a determination result of whether fluctuations in rotation speed of left and right wheels of the vehicle are synchronized or not, and a time difference between a time point when a fluctuation in rotation speed of a first wheel on the front side of the vehicle occurs and a time point when a fluctuation in rotation speed of a second wheel on the rear side of the vehicle occurs.

[0019] According to yet another aspect of the present disclosure, an information processing system includes an information processing device that acquires information about a road surface on which a vehicle runs, and a server that manages information transmitted from the information processing device. The information processing device includes a detection unit that detects fluctuations in rotation speed of each wheel of the vehicle, and a determination unit that determines the condition of the road surface using a determination result of whether fluctuations in rotation speed of left and right wheels of the vehicle are synchronized or not, and a time difference between a time point when a fluctuation in rotation speed of a first wheel on the front side of the vehicle occurs and a time point when a fluctuation in rotation speed of a second wheel on the rear side of the vehicle occurs.

[0020] A vehicle information processing method according to another aspect of the present disclosure is an information processing method for acquiring information about a road surface on which a vehicle runs. This information processing method includes a step of detecting fluctuations in rotation speed of each wheel of the vehicle, and a step of judging a road surface condition using a determination result of whether or not fluctuations in rotation speed of left and right wheels of the vehicle are synchronized and a time difference between a time point when fluctuations in rotation speed of a first wheel on the front side of the vehicle occur and a time point when fluctuations in rotation speed of a second wheel on the rear side of the vehicle occur.

[0021] A program according to yet another aspect of the present disclosure causes a computer to execute the steps of detecting fluctuations in the rotational speed of each wheel of a vehicle traveling on a road surface, and judging the condition of the road surface using the result of determining whether the fluctuations in the rotational speed of the left and right wheels of the vehicle are synchronized and the time difference between the time when the fluctuations in the rotational speed of a first wheel on the front side of the vehicle occur and the time when the fluctuations in the rotational speed of a second wheel on the rear side of the vehicle occur. Effect of the Invention

[0022] According to the present disclosure, it is possible to provide an information processing device, a vehicle, an information processing system, an information processing method, and a program capable of estimating road surface conditions with high accuracy. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of an information processing system. [Diagram 2] 1 is a diagram illustrating a configuration of an example of an information processing device according to an embodiment of the present invention. [Diagram 3] 11 is a diagram for explaining an example of a process executed in a second processing unit. FIG. [Figure 4] 11 is a diagram for explaining an example of processing executed in a third processing unit. FIG. [Diagram 5] 11 is a flowchart showing an example of a process executed by a brake ECU to determine whether a road surface has a single or continuous uneven portion on the left wheel side. [Figure 6] 11 is a flowchart showing an example of a process executed by a brake ECU to determine whether a road surface has a single or continuous uneven portion on the right wheel side. [Figure 7] 10 is a flowchart showing an example of a process executed by a brake ECU to determine whether a road surface has a step or undulation crossing the road surface. [Figure 8] FIG. 2 is a diagram for explaining road surface information. [Figure 9] FIG. 11 is a diagram showing an example of changes in the rotational speed of each wheel when a single roughness occurs on the left wheel side of the road surface. [Figure 10] FIG. 11 is a diagram showing an example of changes in the rotational speed of each wheel when there is continuous roughness on the right side of the road surface. [Figure 11] FIG. 11 is a diagram showing an example of a change in rotation speed of each wheel when a step crosses a road surface. [Figure 12] FIG. 2 is a diagram showing an example of undulations formed on a road surface. [Figure 13] FIG. 4 is a diagram showing an example of changes in the rotational speed of each wheel when the road surface is undulating. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0025] 1 is a diagram for explaining an example of the configuration of an information processing system 1. As shown in FIG. 1, in this embodiment, the information processing system 1 includes a plurality of vehicles 2 and 3, a communication network 6, a base station 7, and a data center 100.

[0026] The vehicles 2 and 3 may be any vehicle that can communicate with the data center 100, and may be, for example, a vehicle driven by an engine, an electric vehicle driven by an electric motor, or a hybrid vehicle equipped with an engine and an electric motor and using at least one of them as a drive source. Note that, for convenience of explanation, only two vehicles 2 and 3 are shown in Fig. 1, but the number of vehicles is not particularly limited to two, and may be three or more.

[0027] The information processing system 1 is configured to acquire predetermined information from vehicles 2 and 3 that are configured to be able to communicate with the data center 100, and to manage the acquired information.

[0028] The data center 100 includes a control device 11, a storage device 12, and a communication device 13. The control device 11, the storage device 12, and the communication device 13 are connected to each other via a communication bus 14 so as to be able to communicate with each other.

[0029] The control device 11 is configured to include a CPU (Central Processing Unit), memory (such as ROM (Read Only Memory) and RAM (Random Access Memory)), and input / output ports for inputting and outputting various signals, all of which are not shown. The various controls performed by the control device 11 are software processes, that is, executed by the CPU reading out programs stored in the memory. The various controls by the control device 11 can also be realized by a general-purpose server (not shown) executing programs stored in a storage medium. However, the various controls by the control device 11 are not limited to software processes and may be processed by dedicated hardware (electronic circuits).

[0030] The storage device 12 stores predetermined information related to a plurality of vehicles 2, 3 configured to be able to communicate with the data center 100. The predetermined information includes, for example, information related to feature amounts calculated in each of the vehicles 2, 3 described below, information for identifying the vehicles 2, 3 (hereinafter referred to as vehicle ID), and information for identifying the positions of the vehicles 2, 3. The vehicle ID is unique information set for each vehicle. The data center 100 becomes able to identify the vehicle that is the source of the transmission by the vehicle ID.

[0031] The communication device 13 realizes two-way communication between the control device 11 and the communication network 6. The data center 100 enables communication with a plurality of vehicles including the vehicles 2 and 3 via a base station 7 provided on the communication network 6 using the communication device 13.

[0032] Next, a description will be given of the specific configuration of the vehicles 2 and 3. Since the vehicles 2 and 3 basically have a common configuration, the following description will be given of the configuration of the vehicle 2 as a representative example.

[0033] The vehicle 2 includes a left front wheel 50 and a right front wheel 51 which are driving wheels, and a left rear wheel 52 and a right rear wheel 53 which are driven wheels. The left front wheel 50 and the right front wheel 51 are rotated by the operation of a driving source, whereby a driving force acts on the vehicle 2, causing the vehicle 2 to travel.

[0034] The vehicle 2 further includes an ADAS-ECU (Electronic Control Unit) 10, a brake ECU 20, a DCM (Data Communication Module) 30, and a central ECU 40.

[0035] The ADAS-ECU 10, the brake ECU 20, and the central ECU 40 are all computers having a processor such as a CPU that executes programs, a memory, and an input / output interface.

[0036] The ADAS-ECU 10 includes a driving assistance system having functions related to driving assistance of the vehicle 2. The driving assistance system is configured to execute implemented applications to realize various functions for assisting driving of the vehicle 2, including at least one of steering control, drive control, and braking control of the vehicle 2. Applications implemented in the driving assistance system include, for example, an application that realizes the functions of an autonomous driving system (AD), an application that realizes the functions of an automatic parking system, and an application that realizes the functions of an advanced driver assistance system (ADAS).

[0037] Examples of ADAS applications include at least one of the following: an application that realizes a function of adaptive cruise control (ACC (Adaptive Cruise Control) etc.) that maintains a constant distance from the vehicle ahead while driving; an application that realizes an auto speed limiter (ASL) function that recognizes vehicle speed limits and maintains the upper limit of the vehicle's speed; an application that realizes a lane keeping assist (LKA (Lane Keeping Assist) or LTA (Lane Tracing Assist) etc.) that maintains the vehicle in the lane in which it is traveling; an application that realizes a collision mitigation braking function (AEB (Autonomous Emergency Braking) or PCS (Pre-Crash Safety) etc.) that automatically applies the brakes to reduce the damage of a collision; and an application that realizes a lane departure warning function (LDW (Lane Departure Warning) or LDA (Lane Departure Alert) etc.) that warns of vehicle 2 departing from the lane it is traveling in.

[0038] Each application of the driving assistance system outputs a request for an action plan that ensures the marketability (function) of the application alone to the brake ECU 20 based on information on the vehicle surroundings and assistance requests from the driver acquired (input) from a plurality of sensors (not shown). The plurality of sensors includes, for example, a vision sensor such as a forward-facing camera, a radar, a LiDAR (Light Detection And Ranging), or a position detection device.

[0039] Each application acquires information on the vehicle's surroundings that is an integration of detection results from one or more sensors as recognition sensor information, and also acquires assistance requests from the driver via a user interface (not shown) such as a switch. Each application can recognize other vehicles, obstacles, or people around the vehicle by, for example, processing images and videos of the vehicle's surroundings acquired by multiple sensors using artificial intelligence (AI) or an image processing processor.

[0040] The action plan also includes, for example, requirements regarding the longitudinal acceleration / deceleration to be generated in the vehicle 2, requirements regarding the steering angle of the vehicle 2, requirements regarding keeping the vehicle 2 stationary, and the like.

[0041] The brake ECU 20 uses detection results from the sensors to control a brake actuator that generates a braking force on the vehicle 2. Furthermore, the brake ECU 20 sets motion requirements for the vehicle 2 to realize the requirements of the action plan from the ADAS-ECU 10. The motion requirements for the vehicle 2 set in the brake ECU 20 are realized by an actuator system (not shown) provided in the vehicle 2. The actuator system includes multiple types of actuator systems, such as a powertrain system, a brake system, and a steering system.

[0042] The brake ECU 20 is connected to, for example, a first wheel speed sensor 54, a second wheel speed sensor 55, a third wheel speed sensor 56, and a fourth wheel speed sensor 57.

[0043] The first wheel speed sensor 54 detects, as the wheel speed, the rotation speed (number of rotations) of the left front wheel 50. The first wheel speed sensor 54 transmits, to the brake ECU 20, a signal indicating the detected rotation speed of the left front wheel 50.

[0044] The second wheel speed sensor 55 detects the rotation speed of the right front wheel 51. The second wheel speed sensor 55 transmits a signal indicating the detected rotation speed of the right front wheel 51 to the brake ECU 20.

[0045] The third wheel speed sensor 56 detects the rotation speed of the left rear wheel 52. The third wheel speed sensor 56 transmits a signal indicating the detected rotation speed of the left rear wheel 52 to the brake ECU 20.

[0046] The fourth wheel speed sensor 57 detects the rotation speed of the right rear wheel 53. The fourth wheel speed sensor 57 transmits a signal indicating the detected rotation speed of the right rear wheel 53 to the brake ECU 20.

[0047] In FIG. 1, the first wheel speed sensor 54, the second wheel speed sensor 55, the third wheel speed sensor 56, and the fourth wheel speed sensor 57 are connected to the brake ECU 20 and the detection results are directly transmitted to the brake ECU 20 as an example. However, any one of the sensors may be connected to another ECU and the detection results may be input to the brake ECU 20 via a communication bus or the central ECU 40.

[0048] Furthermore, the brake ECU 20 receives, for example, information regarding the action plan from the ADAS-ECU 10, as well as information regarding the operating status of various applications, information regarding other driving operations such as shift range, information regarding the behavior of the vehicle 2, and information regarding the position information of the vehicle 2.

[0049] The DCM 30 is a communication module configured to enable two-way communication with the data center 100 .

[0050] The central ECU 40 is configured to be able to communicate with, for example, the brake ECU 20, and is also configured to be able to communicate with the data center 100 using the DCM 30. The central ECU 40 transmits information received from the brake ECU 20 to the data center 100 via the DCM 30, for example.

[0051] In this embodiment, the central ECU 40 has been described as transmitting information received from the brake ECU 20 to the data center 100 via the DCM 30, but it may also have a function such as relaying communications between various ECUs (a gateway function), or it may include a memory (not shown) whose stored contents can be updated using update information from the data center 100, and predetermined information including update information stored in the memory from the various ECUs is read out when the system of the vehicle 2 is started.

[0052] In the vehicle 2 having the above configuration, the brake ECU 20 can detect changes in the state of the vehicle 2 while it is traveling (for example, fluctuations in the rotation speed of each wheel) using information obtained from sensors provided in the vehicle 2, and estimate the road surface conditions using the detection results. Such an estimation result of the road surface conditions can be used, for example, to determine whether or not the road surface needs to be repaired, and therefore it is required to estimate the road surface conditions with high accuracy.

[0053] Therefore, in this embodiment, the brake ECU 20 judges the road surface condition using the result of the judgment as to whether the fluctuations in the rotation speeds of the left and right wheels of the vehicle 2 are synchronized or not, and the time difference between the time point when the fluctuations in the rotation speeds of the front wheels of the vehicle 2 occur and the time point when the fluctuations in the rotation speeds of the rear wheels of the vehicle 2 occur. In this embodiment, the left and right wheels of the vehicle 2 are wheels on the same rotation axis, and include a combination of a left front wheel 50 and a right front wheel 51, and a combination of a left rear wheel 52 and a right rear wheel 53. Furthermore, in this embodiment, the front wheels and rear wheels of the vehicle 2 are front and rear wheels on one side, and include a combination of a left front wheel 50 and a left rear wheel 52, and a combination of a right front wheel 51 and a right rear wheel 53.

[0054] Fluctuations in the rotational speed of each wheel caused by steps and unevenness on the road surface are synchronized or linked between the wheels, so the road surface conditions can be determined with high accuracy by using the determination result of whether the fluctuations in the rotational speed of the left and right wheels of vehicle 2 are synchronized or not and the time difference.

[0055] 2 is a diagram for explaining the configuration of an example of an information processing device according to the present embodiment. The information processing device according to the present embodiment is realized by the brake ECU 20.

[0056] The brake ECU 20 includes a first processing unit 22, a second processing unit 24, and a third processing unit 26. The first processing unit 22 receives information indicating detection results from various sensors as information related to the behavior of the vehicle 2. The first processing unit 22 outputs, to the second processing unit 24, input information received during a period during which a predetermined condition is satisfied during a period during which the input information is received.

[0057] The second processing unit 24 calculates a feature amount related to the operation of the vehicle 2 by using the input information received during a period in which a predetermined condition is satisfied during the period in which the input information is received.

[0058] Fig. 3 is a diagram for explaining an example of processing executed by the second processing unit 24. As shown in Fig. 3, the second processing unit 24 receives the rotation speeds of the left front wheel 50, the right front wheel 51, the left rear wheel 52, and the right rear wheel 53 as input information from the first processing unit 22. The second processing unit 24 uses this input information to determine whether or not a predetermined condition is satisfied.

[0059] The predetermined conditions include a condition that the rotation speed of each wheel is constant. More specifically, the predetermined conditions include a condition that the amount of change in the rotation speed of each wheel during a predetermined period is equal to or less than a threshold value.

[0060] When it is determined that the predetermined condition is satisfied, the second processing unit 24 turns on a satisfaction flag, and outputs a signal indicating the state of the satisfaction flag as a scene identification signal.

[0061] When it is determined that the predetermined condition is satisfied, the second processing unit 24 calculates a feature amount related to the operation of the vehicle 2 by using the input information received during the period in which the predetermined condition is satisfied.

[0062] In this embodiment, the feature value indicates, for example, a fluctuation in the rotation speed that occurs depending on the road surface condition. In this embodiment, when a change occurs in which the difference between the maximum and minimum values ​​of the rotation speed of the left front wheel 50 in a predetermined period exceeds a threshold value after a predetermined condition is satisfied, the second processing unit 24 outputs, as a feature value, a determination result that a fluctuation has occurred in the rotation speed of the left front wheel 50 in the predetermined period. That is, when a fluctuation has occurred in the rotation speed of the left front wheel 50, for example, the second processing unit 24 sets a flag indicating that a fluctuation has occurred in the rotation speed of the left front wheel 50 to an ON state.

[0063] The second processing unit 24 judges whether or not fluctuations have occurred in the rotation speed of the right front wheel 51, the left rear wheel 52, and the right rear wheel 53 in the same manner, and calculates the judgment result (a flag indicating that a fluctuation has occurred in the rotation speed corresponding to each wheel) as a feature amount. For example, when a predetermined condition is met, the second processing unit 24 judges that a rotation fluctuation has occurred in each wheel, and outputs the feature amount indicating the judgment result in association with time together with a scene identification signal. The second processing unit 24 repeatedly executes the above-mentioned process during a period in which the predetermined condition is met.

[0064] The third processing unit 26 generates information about the condition of the road surface using the information output from the second processing unit 24. For example, the third processing unit 26 generates information about the condition of the road surface on which the vehicle 2 is traveling using the information output from the second processing unit 24 when the state of the establishment flag included in the scene identification signal is a predetermined state (for example, an on state).

[0065] Fig. 4 is a diagram for explaining an example of processing executed by the third processing unit 26. As shown in Fig. 4, the third processing unit 26 receives information indicating a scene identification signal, a feature amount, and time from the second processing unit 24. The third processing unit 26 outputs information regarding the road surface condition to the central ECU 40.

[0066] The central ECU 40 transmits the information input from the third processing unit 26 to the data center 100 via the DCM 30.

[0067] The data center 100 uses the output value of the third processing unit 26 to determine whether or not the target road surface is passable by vehicles and whether or not repair work on the road surface is required.

[0068] The information transmitted from the DCM 30 to the data center 100 includes, for example, the processing time, vehicle position information, road surface position information, and information on the road surface condition. Therefore, the data center 100 stores the information input from the DCM 30 as a single piece of data in the storage device 12. This enables the data center 100 to obtain information on the condition of the road surface on which each of the vehicles 2 and 3 capable of communicating with the data center 100 is traveling.

[0069] Next, an example of processing executed by the brake ECU 20 of the vehicle 2 will be described with reference to Fig. 5, Fig. 6, and Fig. 7. Fig. 5 is a flowchart showing an example of processing executed by the brake ECU 200 to determine whether a road surface has a single or continuous uneven portion on the left wheel side. A series of processing shown in this flowchart is repeatedly executed by the brake ECU 20 at every predetermined control period.

[0070] In step (hereinafter, step will be abbreviated as S) 100, the brake ECU 20 acquires data corresponding to input information. Specifically, the brake ECU 20 acquires data corresponding to input information including, for example, information on the rotation speeds of the left front wheel 50, the right front wheel 51, the left rear wheel 52, and the right rear wheel 53.

[0071] In S102, the brake ECU 20 determines whether or not the predetermined conditions are satisfied. As described above, the predetermined conditions include a condition that the rotation speed of each wheel remains constant. The determination method is as described above, and therefore detailed description thereof will not be repeated. If it is determined that the predetermined conditions are satisfied (YES in S102), the process proceeds to S104.

[0072] In S104, the brake ECU 20 determines whether or not there is a fluctuation in the left front wheel 50. The method of determining the fluctuation is as described above, and therefore detailed description thereof will not be repeated. If it is determined that there is a fluctuation in the left front wheel 50 (YES in S104), the process proceeds to S106.

[0073] In S106, the brake ECU 20 determines whether or not there is a fluctuation in the right front wheel 51. The method for determining whether or not there is a fluctuation in the right front wheel 51 is similar to the method for determining whether or not there is a fluctuation in the left front wheel 50, and therefore detailed description thereof will not be repeated. If it is determined that there is a fluctuation in the right front wheel 51 (YES in S106), this process is ended. On the other hand, if it is determined that there is no fluctuation in the right front wheel 51 (NO in S106), the process proceeds to S108.

[0074] In S108, the brake ECU 20 determines whether the left rear wheel 52 fluctuates with a time difference according to the vehicle speed and wheelbase (hereinafter referred to as WB). That is, the brake ECU 20 determines whether a fluctuation has occurred in the left rear wheel 52 at the point in time when a movement period in which the vehicle 2 moves by the amount of WB has elapsed since the point in time when a fluctuation has occurred in the left front wheel 50.

[0075] More specifically, the brake ECU 20 determines that the left rear wheel 52 has fluctuated with a time difference corresponding to the vehicle speed and WB when, for example, the magnitude of the difference between the time from when a fluctuation occurs in the left front wheel 50 to when a fluctuation occurs in the left rear wheel 52 and a movement period calculated using the vehicle speed and WB is equal to or less than a threshold value. Note that the method of determining whether or not there is a fluctuation in the left rear wheel 52 is similar to the method of determining whether or not there is a fluctuation in the left front wheel 50, and therefore detailed description thereof will not be repeated. If it is determined that the left rear wheel 52 has fluctuated with a time difference corresponding to the vehicle speed and WB (YES in S108), the process proceeds to S110.

[0076] In S110, the brake ECU 20 determines whether the fluctuation of the left wheel continues. For example, if the fluctuation range (magnitude of the difference between the maximum value and the minimum value) of the rotation speed of the left front wheel 50 in a predetermined period after the fluctuation of the left front wheel 50 is detected is greater than a threshold value, the brake ECU 20 determines that the fluctuation of the left wheel continues. Note that the brake ECU 20 may determine that the fluctuation of the left wheel continues if, for example, the fluctuation range of the rotation speed of the left rear wheel 52 in a predetermined period after the fluctuation of the left rear wheel 52 is detected is greater than a threshold value. If it is determined that the fluctuation of the left wheel continues (YES in S110), the process proceeds to S112.

[0077] In S112, the brake ECU 20 determines whether or not there is continuous roughness on the road surface in the trajectories of the left and right wheels. For example, when a flag indicating that there is a continuous uneven portion on the road surface on the right wheel side (hereinafter, the uneven portion is also referred to as "roughness") is in an on state, the brake ECU 20 determines that there is continuous roughness on the road surface on both the left and right wheel sides. If it is determined that there is continuous roughness on the road surface in the trajectories of the left and right wheels (YES in S112), the process proceeds to S114.

[0078] In S114, the brake ECU 20 determines that there is continuous roughness on the road surface along the trajectories of the left and right wheels, and sets a flag indicating that there is continuous roughness on the road surface of the left and right wheels to an ON state. In this case, the brake ECU 20 sets the flag indicating that there is continuous roughness on the road surface on the right wheel side from an ON state to an OFF state. Thereafter, the process proceeds to S120. Note that, if it is determined that the fluctuation of the left wheel will not continue (NO in S110), the process proceeds to S116.

[0079] In S116, the brake ECU 20 determines that there is a single roughness on the road surface along the path of the left wheel. In this case, the brake ECU 20 sets a flag indicating that there is a single roughness on the road surface on the left wheel side to an ON state. Thereafter, the process proceeds to S120. On the other hand, if it is determined that there is no continuous roughness on the road surface along the paths of the left and right wheels (NO in S112), the process proceeds to S118.

[0080] In S118, the brake ECU 20 determines that there is continuous roughness on the road surface along the path of the left wheel. In this case, the brake ECU 20 sets a flag indicating that there is continuous roughness on the road surface on the left wheel side to an ON state. Thereafter, the process proceeds to S120. The process executed by the second processing unit 24 includes the process of S100, the process of S102, the process of S104, the process of S106, the process of S108, the process of S110, the process of S112, the process of S114, the process of S116, and the process of S118.

[0081] In S120, the brake ECU 20 executes pre-transmission processing. The brake ECU 20 generates, in the data center 100, information for identifying the position of the road surface that is the subject of the determination of the road surface condition in the brake ECU 20 and the road surface condition at that position. The brake ECU 20 generates the road surface information using, for example, various flags related to the road surface conditions described above. An example of the road surface information generated in the brake ECU 20 will be described later. After that, the process proceeds to S122.

[0082] In S122, the brake ECU 20 executes a transmission process. The brake ECU 20 transmits the generated information to the central ECU 40. The central ECU 40 transmits the received information to the data center 100 via the DCM 30. The above-described processes of S120 and S122 correspond to the processes executed by the third processing unit 26. Then, the process ends.

[0083] If it is determined that there is no fluctuation in the left front wheel 50 (NO in S104) or if the left rear wheel 52 does not fluctuate with a time difference according to the vehicle speed and WB (NO in S108), this process ends.

[0084] The data center 100 uses the received information to determine whether or not the road surface that is the subject of the determination is passable by vehicles, and whether or not the damage state of the road surface requires repair or maintenance. The information transmitted to the data center 100 and the processing executed in the data center 100 are as described above, and therefore will not be described in detail again. The processing then ends.

[0085] 6 is a flowchart showing an example of a process for determining whether a road surface has a single or continuous uneven portion on the right wheel side, which is executed by the brake ECU 200. A series of processes shown in this flowchart is repeatedly executed by the brake ECU 20 at every predetermined control period.

[0086] In S200, the brake ECU 20 acquires data corresponding to the input information. Since the input information is as described above, detailed description thereof will not be repeated.

[0087] In S202, the brake ECU 20 determines whether or not a predetermined condition is satisfied. The predetermined condition and the method of determination are as described above, and therefore detailed description thereof will not be repeated. If it is determined that the predetermined condition is satisfied (YES in S202), the process proceeds to S204.

[0088] In S204, the brake ECU 20 determines whether or not there is a fluctuation in the right front wheel 51. The method of determining whether or not there is a fluctuation in the right front wheel 51 is as described above, and therefore detailed description thereof will not be repeated. If it is determined that there is a fluctuation in the right front wheel 51 (YES in S204), the process proceeds to S206.

[0089] In S206, the brake ECU 20 determines whether or not there is a fluctuation in the left front wheel 50. The method of determining whether or not there is a fluctuation in the left front wheel 50 is as described above, and therefore detailed description thereof will not be repeated. If it is determined that there is a fluctuation in the left front wheel 50 (YES in S206), this process ends. On the other hand, if it is determined that there is no fluctuation in the left front wheel 50 (NO in S206), the process proceeds to S208.

[0090] In S208, the brake ECU 20 determines whether the right rear wheel 53 fluctuates with a time difference according to the vehicle speed and WB. That is, the brake ECU 20 determines whether a fluctuation has occurred in the right rear wheel 53 at the point in time when a movement period in which the vehicle 2 moves by the amount of WB has elapsed since the point in time when a fluctuation has occurred in the right front wheel 51. The specific method of determination is similar to the above-mentioned method of determining whether the left rear wheel 52 fluctuates with a time difference according to the vehicle speed and WB, and therefore detailed description thereof will not be repeated. If it is determined that the right rear wheel 53 fluctuates with a time difference according to the vehicle speed and WB (YES in S208), the process proceeds to S210.

[0091] In S210, the brake ECU 20 determines whether the fluctuation of the right wheel continues. The method of determining whether the fluctuation of the right wheel continues is similar to the method of determining whether the fluctuation of the left wheel continues, and therefore detailed description thereof will not be repeated. If it is determined that the fluctuation of the right wheel continues (YES in S210), the process proceeds to S212.

[0092] In S212, the brake ECU 20 determines whether or not there is continuous roughness on the road surface in the trajectories of the left and right wheels. For example, when a flag indicating that there is continuous roughness on the road surface on the left wheel side is in an on state, the brake ECU 20 determines that there is continuous roughness on the road surface on both the left and right wheel sides. If it is determined that there is continuous roughness on the road surface in the trajectories of the left and right wheels (YES in S212), the process proceeds to S214.

[0093] In S214, the brake ECU 20 determines that there is continuous roughness on the road surface along the trajectories of the left and right wheels, and sets a flag indicating that there is continuous roughness on the road surface of the left and right wheels to an ON state. In this case, the brake ECU 20 sets the flag indicating that there is continuous roughness on the road surface on the left wheel side from an ON state to an OFF state. Thereafter, the process proceeds to S220. Note that, if it is determined that the fluctuation of the right wheel does not continue (NO in S210), the process proceeds to S216.

[0094] In S216, the brake ECU 20 determines that there is a single roughness on the road surface on the path of the right wheel. In this case, the brake ECU 20 sets a flag indicating that there is a single roughness on the road surface on the right wheel side to an ON state. Thereafter, the process proceeds to S220. On the other hand, if it is determined that there is no continuous roughness on the road surface on the path of the left and right wheels (NO in S212), the process proceeds to S218.

[0095] In S218, the brake ECU 20 determines that there is continuous roughness on the road surface along the path of the right wheel. In this case, the brake ECU 20 sets a flag indicating that there is continuous roughness on the road surface on the right wheel side to an ON state. Then, the process proceeds to S220. The above-mentioned processes of S200, S202, S204, S206, S208, S210, S212, S214, S216, and S218 correspond to the processes executed by the second processing unit 24.

[0096] In S220, the brake ECU 20 executes the pre-transmission process. Since the pre-transmission process is as described above, detailed description thereof will not be repeated. Then, the process proceeds to S220.

[0097] In S220, the brake ECU 20 executes the transmission process. The transmission process is as described above, and therefore the detailed description thereof will not be repeated. Then, the process ends.

[0098] 7 is a flowchart showing an example of a process for determining whether a road surface has a step or undulation crossing the road surface, which is executed by the brake ECU 20. A series of processes shown in this flowchart is repeatedly executed by the brake ECU 20 at every predetermined control period.

[0099] In S300, the brake ECU 20 acquires data corresponding to the input information. Since the input information is as described above, detailed description thereof will not be repeated.

[0100] In S302, the brake ECU 20 determines whether or not a predetermined condition is satisfied. The predetermined condition and the method of determination are as described above, and therefore detailed description thereof will not be repeated. If it is determined that the predetermined condition is satisfied (YES in S302), the process proceeds to S304.

[0101] In S304, the brake ECU 20 determines whether or not there is a fluctuation in the left front wheel 50. The method of determining whether or not there is a fluctuation in the left front wheel 50 is as described above, and therefore detailed description thereof will not be repeated. If it is determined that there is a fluctuation in the left front wheel 50 (YES in S304), the process proceeds to S306.

[0102] In S306, the brake ECU 20 determines whether or not there is a fluctuation in the right front wheel 51. The method of determining whether or not there is a fluctuation in the right front wheel 51 is as described above, and therefore detailed description thereof will not be repeated. If it is determined that there is a fluctuation in the right front wheel 51 (YES in S306), the process proceeds to S308.

[0103] In S308, the brake ECU 20 determines whether the fluctuations of the left front wheel 50 and the right front wheel 51 are synchronized. The brake ECU 20 determines that the fluctuations of the left front wheel 50 and the right front wheel 51 are synchronized when the difference between the time when the fluctuations in the rotation speed of the left front wheel 50 occurred and the time when the fluctuations in the rotation speed of the right front wheel 51 occurred is equal to or less than a threshold value. The time when the fluctuations occurred may be the time when the rotation speed is at its maximum value or the time when the rotation speed is at its minimum value. If it is determined that the fluctuations of the left front wheel 50 and the right front wheel 51 are synchronized (YES in S308), the process proceeds to S310.

[0104] In S310, the brake ECU 20 determines whether or not there is a fluctuation in the left rear wheel 52. The method of determining whether or not there is a fluctuation in the left rear wheel 52 is as described above, and therefore detailed description thereof will not be repeated. If it is determined that there is a fluctuation in the left rear wheel 52 (YES in S310), the process proceeds to S312.

[0105] In S312, the brake ECU 20 determines whether or not there is a fluctuation in the right rear wheel 53. The method of determining whether or not there is a fluctuation in the right rear wheel 53 is as described above, and therefore detailed description thereof will not be repeated.

[0106] In S314, the brake ECU 20 determines whether or not the fluctuations of the left rear wheel 52 and the right rear wheel 53 are synchronized. The method of determining whether or not the fluctuations of the left rear wheel 52 and the right rear wheel 53 are synchronized is similar to the method of determining whether or not the fluctuations of the left front wheel 50 and the right front wheel 51 are synchronized, and therefore detailed description thereof will not be repeated. If it is determined that the fluctuations of the left rear wheel 52 and the right rear wheel 53 are synchronized (YES in S314), the process proceeds to S316.

[0107] In S316, the brake ECU 20 determines whether or not there is a time difference between before and after the time corresponding to the vehicle speed and WB. That is, the brake ECU 20 determines whether or not a fluctuation has occurred in the rear wheels at the time when a movement period during which the vehicle 2 moves by the amount of WB has elapsed since the time when a fluctuation has occurred in the front wheels.

[0108] More specifically, the brake ECU 20 determines that there is a time difference between the vehicle speed and WB when the magnitude of the difference between the time from the occurrence of fluctuation in the front wheel (left front wheel 50 or right front wheel 51) to the occurrence of fluctuation in the rear wheel (left rear wheel 52 or right rear wheel 53) and the travel period calculated using the vehicle speed and WB is equal to or smaller than a threshold value. If it is determined that there is a time difference between the vehicle speed and WB (YES in S316), the process proceeds to S318.

[0109] In S318, the brake ECU 20 determines whether or not fluctuations have occurred at the front and rear wheels two or more times. More specifically, the brake ECU 20 determines whether or not fluctuations have occurred at the front and rear wheels two or more times within a time period during which the vehicle 2 travels a predetermined distance. The predetermined distance is, for example, a distance that is set based on the length of a typical bridge, and includes a distance of, for example, a few meters to a dozen meters. If it is determined that fluctuations have occurred at the front and rear wheels two or more times (YES in S318), the process proceeds to S320.

[0110] In S320, the brake ECU 20 determines that the road surface is undulating and made up of a plurality of steps. In this case, the brake ECU 20 sets a flag indicating that the road surface is undulating to an ON state. Thereafter, the process proceeds to S324. If it is determined that the fluctuations at the front and rear wheels have not occurred two or more times (only once) (NO in S318), the process proceeds to S322.

[0111] In S322, the brake ECU 20 determines that the road surface has a step that crosses the lane. In this case, the brake ECU 20 sets a flag indicating that the road surface has a step to an ON state. Then, the process proceeds to S324.

[0112] In S324, the brake ECU 20 executes the pre-transmission process. Since the pre-transmission process is as described above, detailed description thereof will not be repeated.

[0113] In S326, the brake ECU 20 executes the transmission process. Since the transmission process is as described above, detailed description thereof will not be repeated.

[0114] In each pre-transmission process in the processing of the flowcharts shown in FIG. 5, FIG. 6, and FIG. 7, road surface information is generated, and is transmitted to the data center 100 in the transmission process in association with the position information and time information.

[0115] FIG. 8 is a diagram for explaining road surface information. As shown in FIG. 8, the information transmitted to the data center 100 includes, in addition to the above-mentioned position information and time information, (1) the fluctuation amount of the rotation speed of each wheel, (2) the roughness level of the road surface when the traveling road surface is a paved road, (3) the roughness level of the road surface when the traveling road surface is a dirt road, and (4) road surface information based on the fluctuation information of the four wheels. For example, the brake ECU 20 sets the change history of the rotation speed during the period when the fluctuation occurs as the fluctuation amount of the rotation speed of each wheel (1). Furthermore, the brake ECU 20 judges whether the traveling road surface is a paved road or a dirt road based on, for example, the difference in rotation speed between the driving wheels and the driven wheels when the vehicle 2 starts, information acquired by a camera or the like, map information, and the position information of the vehicle 2. The brake ECU 20 sets the roughness level based on the fluctuation range of the rotation speed. The brake ECU 20 sets one of the information (2) and (3) based on the judgment result of the traveling road surface and the set roughness level. The road surface information includes (0) smooth, (1) single rough on the left side, (2) single rough on the right side, (3) continuous rough on the left side, (4) continuous rough on the right side, (5) continuous rough on both sides, (6) crossing step, and (7) undulation. The brake ECU 20 sets the above road surface information using the states of flags (corresponding to the fluctuation information of the four wheels) set by the processing of the flowcharts shown in Figures 5, 6, and 7.

[0116] The operation of the brake ECU 20, which is the information processing device according to this embodiment based on the above-described structure and flowchart, will be described with reference to FIGS.

[0117] <If there is a single rough spot on the left side of the road> FIG. 9 is a diagram showing an example of changes in the rotational speed of each wheel when there is a single roughness on the left side of the road surface. The vertical axis of FIG. 9 indicates the rotational speed of each wheel. The horizontal axis of FIG. 9 indicates time. LN1 of FIG. 9 indicates changes in the rotational speed of the right front wheel 51. LN2 of FIG. 9 indicates changes in the rotational speed of the left front wheel 50. LN3 of FIG. 9 indicates changes in the rotational speed of the right rear wheel 53. LN4 of FIG. 9 indicates changes in the rotational speed of the left rear wheel 52.

[0118] 9, before time T(0), for example, when the vehicle 2 is traveling on a smooth road surface, the vehicle 2 continues traveling without a large fluctuation in rotation speed. When the rotation speed of each wheel is detected at this time, it is accumulated in the memory or the like of the brake ECU 20. When input information is acquired from the memory (S100), it is determined that a predetermined condition is established (YES in S102).

[0119] At time T(0), when the left front wheel 50 passes over a single depression formed on the road surface, the rotation speed of the left front wheel 50 increases temporarily and then decreases, causing a fluctuation with a fluctuation range equal to or greater than the threshold value. If there is a fluctuation in the left front wheel 50 (YES in S104) and there is no fluctuation in the right front wheel 51 (NO in S106), it is determined whether or not the left rear wheel 52 fluctuates with a time difference according to the vehicle speed and WB (S108).

[0120] At time T(1) after the vehicle 2 has moved the distance WB from time T(0) while maintaining the vehicle speed, if the left rear wheel 52 passes through a single depression formed in the road surface, a fluctuation occurs in the rotation speed of the left rear wheel 52. Therefore, if a fluctuation occurs in the left rear wheel 52 with a time difference according to the vehicle speed and WB (YES in S108) and the fluctuation of the left wheel does not continue thereafter (NO in S110), it is determined that there is a single roughness on the left wheel side of the road surface (S116). Road surface information based on this determination result is generated by execution of a pre-transmission process (S120), and a transmission process is executed in which the generated road surface information is transmitted to the data center 100 (S122).

[0121] Such information is collected from other vehicles as well, and is used to determine whether the road, including the roughness of the road surface, requires repair and whether vehicles can pass through.

[0122] <When there is continuous roughness on the right side of the road> FIG. 10 is a diagram showing an example of changes in the rotational speed of each wheel when there is continuous roughness on the right side of the road surface. The vertical axis of FIG. 10 indicates the rotational speed of each wheel. The horizontal axis of FIG. 10 indicates time. LN5 of FIG. 10 indicates changes in the rotational speed of the right front wheel 51. LN6 of FIG. 10 indicates changes in the rotational speed of the left front wheel 50. LN7 of FIG. 10 indicates changes in the rotational speed of the right rear wheel 53. LN8 of FIG. 10 indicates changes in the rotational speed of the left rear wheel 52.

[0123] 10, before time T(2), for example, when the vehicle 2 is traveling on a smooth road surface, the vehicle 2 continues traveling without a large fluctuation in rotation speed. At this time, when the rotation speed of each wheel is detected, it is accumulated in a memory or the like of the brake ECU 20. When input information is acquired from the memory (S200), it is determined that a predetermined condition is established (YES in S202).

[0124] At time T(2), when the right front wheel 51 passes through successive recesses formed on the road surface, the rotation speed of the right front wheel 51 temporarily increases and then decreases, and this operation is repeated. At this time, fluctuations occur with a fluctuation range equal to or greater than the threshold value. If there is a fluctuation in the right front wheel 51 (YES in S204) and there is no fluctuation in the left front wheel 50 (NO in S206), it is determined whether or not the left rear wheel 52 fluctuates with a time difference according to the vehicle speed and WB (S208).

[0125] At time T(3) after the vehicle 2 has moved by WB from time T(2), when the right rear wheel 53 passes through successive recesses formed on the road surface, a fluctuation occurs in the rotation speed of the right rear wheel 53. Therefore, if a fluctuation occurs in the right rear wheel 53 with a time difference according to the vehicle speed and WB (YES in S208), and the fluctuation of the right wheel continues thereafter (YES in S210), and there is no successive roughness on the left wheel, it is determined that there is a successive roughness (groove portion) on the road surface on the right wheel side (S218). Road surface information based on this determination result is generated by executing a pre-transmission process (S220), and a transmission process is executed in which the generated road surface information is transmitted to the data center 100 (S222).

[0126] <When there is a step across the road> FIG. 11 is a diagram showing an example of changes in rotational speed of each wheel when there is a step across the road surface. The vertical axis of FIG. 11 indicates the rotational speed of each wheel. The horizontal axis of FIG. 11 indicates time. LN9 of FIG. 11 indicates changes in rotational speed of right front wheel 51. LN10 of FIG. 11 indicates changes in rotational speed of left front wheel 50. LN11 of FIG. 11 indicates changes in rotational speed of right rear wheel 53. LN12 of FIG. 11 indicates changes in rotational speed of left rear wheel 52.

[0127] 11, before time T(4), for example, when the vehicle 2 is traveling on a smooth road surface, the vehicle 2 continues traveling without a large fluctuation in rotation speed. At this time, when the rotation speed of each wheel is detected, it is accumulated in a memory or the like of the brake ECU 20. When input information is acquired from the memory (S300), it is determined that a predetermined condition is established (YES in S302).

[0128] At time T(4), if there is a fluctuation in the left front wheel 50 (YES in S304) and there is a fluctuation in the right front wheel 51 (YES in S306), it is determined whether the fluctuation in the left front wheel 50 and the fluctuation in the right front wheel 51 are synchronized (S308). Because the time point at which the fluctuation in the left front wheel 50 and the time point at which the fluctuation in the right front wheel 51 occurred are both time T(4), it is determined that the fluctuation in the left front wheel 50 and the fluctuation in the right front wheel 51 are synchronized (YES in S308).

[0129] Furthermore, at time T(5) after the vehicle 2 has moved by the distance WB from time T(4), if there is a fluctuation in the left rear wheel 52 (YES in S310) and there is a fluctuation in the right rear wheel 53 (YES in S312), it is determined whether the fluctuation in the left rear wheel 52 and the fluctuation in the right rear wheel 53 are synchronized (S314). Because the fluctuation in the left rear wheel 52 and the fluctuation in the right rear wheel 53 both occur at time T(5), it is determined that the fluctuation in the left rear wheel 52 and the fluctuation in the right rear wheel 53 are synchronized (YES in S314).

[0130] Therefore, since the time difference between the time when the fluctuation of the left front wheel 50 occurs and the time when the fluctuation of the left rear wheel 52 occurs is a time difference according to the vehicle speed and WB (YES in S316), it is determined whether or not the fluctuation of the front and rear has occurred two or more times (S318). If the fluctuation of the front and rear is not detected after time T(5), it is determined that the fluctuation of the front and rear wheels has not occurred two or more times (NO in S318), and it is determined that there is a step crossing the road surface (S322). Road surface information based on this determination result is generated by executing a pre-transmission process (S324), and a transmission process is executed in which the generated road surface information is transmitted to the data center 100 (S326).

[0131] <When the road surface is undulating> Fig. 12 is a diagram showing an example of swells formed on a road surface. As shown in Fig. 12, when a section that is a bridge or an overpass is present on the travel route of the vehicle 2, multiple steps may be formed immediately before or immediately after the section. This is because a stepping board is installed immediately before or immediately after the section, and a step is formed at the boundary between the stepping board and the bridge or overpass due to deterioration of the road. Such multiple steps form swells on the road surface.

[0132] FIG. 13 is a diagram showing an example of changes in rotation speed of each wheel when the road surface is undulating. The vertical axis of FIG. 13 indicates the rotation speed of each wheel. The horizontal axis of FIG. 13 indicates time. LN13 in FIG. 13 indicates changes in rotation speed of right front wheel 51. LN14 in FIG. 13 indicates changes in rotation speed of left front wheel 50. LN15 in FIG. 13 indicates changes in rotation speed of right rear wheel 53. LN16 in FIG. 13 indicates changes in rotation speed of left rear wheel 52.

[0133] 13, before time T(6), for example, when the vehicle 2 is traveling on a smooth road surface, the vehicle 2 continues traveling without a large fluctuation in rotation speed. At this time, when the rotation speed of each wheel is detected, it is accumulated in a memory or the like of the brake ECU 20. When input information is acquired from the memory (S300), it is determined that a predetermined condition is established (YES in S302).

[0134] At time T(6), if there is a fluctuation in the left front wheel 50 (YES in S304) and there is a fluctuation in the right front wheel 51 (YES in S306), it is determined whether the fluctuation in the left front wheel 50 and the fluctuation in the right front wheel 51 are synchronized (S308). Because the time point at which the fluctuation in the left front wheel 50 and the time point at which the fluctuation in the right front wheel 51 occurred are both time T(6), it is determined that the fluctuation in the left front wheel 50 and the fluctuation in the right front wheel 51 are synchronized (YES in S308).

[0135] Furthermore, at time T(7) after the vehicle 2 has moved by the distance WB from time T(6), if there is a fluctuation in the left rear wheel 52 (YES in S310) and there is a fluctuation in the right rear wheel 53 (YES in S312), it is determined whether the fluctuation in the left rear wheel 52 and the fluctuation in the right rear wheel 53 are synchronized (S314). Because the time when the fluctuation in the left rear wheel 52 and the time when the fluctuation in the right rear wheel 53 occurred are both time T(7), it is determined that the fluctuation in the left rear wheel 52 and the fluctuation in the right rear wheel 53 are synchronized (YES in S314).

[0136] Therefore, since the time difference between the time when the fluctuation of the left front wheel 50 occurs and the time when the fluctuation of the left rear wheel 52 occurs is a time difference according to the vehicle speed and WB (YES in S316), it is determined whether the fluctuation of the front and rear wheels has occurred two or more times (S318). If the fluctuation of the front and rear wheels is detected again at time T(8) and time T(9) after time T(7), it is determined that the fluctuation of the front and rear wheels has occurred two or more times (YES in S318), and therefore it is determined that the road surface is undulating (S320). Road surface information based on this determination result is generated by executing a pre-transmission process (S324), and a transmission process is executed in which the generated road surface information is transmitted to the data center 100 (S326).

[0137] As described above, according to the information processing device of this embodiment, since the fluctuations in the rotational speed of each wheel caused by roughness such as steps and uneven parts formed on the road surface are synchronized or linked between the wheels, the road surface condition can be determined with high accuracy by using the determination result of whether the fluctuations in the rotational speed of the left and right wheels of the vehicle 2 are synchronized or not and the time difference. Therefore, it is possible to provide an information processing device, vehicle, information processing system, information processing method, and program that can estimate the road surface condition with high accuracy.

[0138] Furthermore, if the fluctuating state of the wheels continues after a fluctuation in the wheel rotation speed has occurred, this means that the vehicle is continuing to travel over grooves or ridges with continuous unevenness, making it possible to accurately determine that the road surface is one in which the unevenness extends along the wheel trajectory.

[0139] Furthermore, when the fluctuations in the rotational speeds of the left and right wheels are synchronized, the left and right wheels have passed over a step crossing the road surface, making it possible to accurately determine that a step crossing the road surface has formed on the road surface.

[0140] Furthermore, if the number of times that it is determined that a step has been formed exceeds two, it can be determined with high accuracy that an undulation consisting of a plurality of steps has been formed on the road surface.

[0141] Furthermore, information about road surface conditions that is valuable to the user (road surface information) can be calculated while being concealed so that individuals cannot be identified.

[0142] Furthermore, information about the road surface conditions (road surface information) for determining whether or not road surface repair is required can be transmitted outside the vehicle by the transmitting unit DCM30, thereby improving the usefulness of the road surface information.

[0143] Furthermore, when the feature quantities are calculated within the vehicle, there is no need to transmit information for calculating the feature quantities to the outside. Therefore, when the amount of information required for calculating the feature quantities is large, transmission of unnecessary information to the outside of the vehicle is suppressed, and an increase in communication load and storage capacity and processing costs at the data center 100 are suppressed.

[0144] Furthermore, by separately calculating the feature quantities and calculating the feature quantity change history in the second processing unit 24 and the third processing unit 26, it is possible to use the method of calculating the feature quantity change history in the third processing unit 26 for generating other road surface information by changing only the method. Note that such a change can be realized, for example, by the brake ECU 20 reading update information received from the data center 100 and stored in the memory of the central ECU 40.

[0145] Modifications will be described below.

[0146] In the above-described embodiment, an example has been described in which the input information input to the brake ECU 20 is processed within the brake ECU 20 by the processing shown in the flowcharts of Figures 5, 6, and 7, thereby calculating the feature quantities and the change history of the feature quantities. However, the processing may also be performed in the data center 100.

[0147] Furthermore, in the above embodiment, the vehicle 2 has been described as a four-wheeled vehicle by way of example, but the vehicle may have four or more wheels.

[0148] The above-described modified examples may be implemented in whole or in part in appropriate combination.

[0149] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0150] 1 information processing system, 2, 3 vehicle, 6 communication network, 7 base station, 11 control device, 12 storage device, 13 communication device, 14 communication bus, 20 brake ECU, 22 first processing unit, 24 second processing unit, 26 third processing unit, 30 DCM, 40 central ECU, 50 left front wheel, 51 right front wheel, 52 left rear wheel, 53 right rear wheel, 54 first wheel speed sensor, 55 second wheel speed sensor, 56 third wheel speed sensor, 57 fourth wheel speed sensor, 100 data center.

Claims

1. An information processing device that acquires information about a road surface on which a vehicle is traveling, A detection unit that detects fluctuations in the rotational speed of each wheel of the vehicle; a determination unit that determines the road surface condition based on a determination result of whether fluctuations in the rotation speeds of the left and right wheels of the vehicle are synchronized and a time difference between a time point when a fluctuation in the rotation speed of a first wheel on a front side of the vehicle occurs and a time point when a fluctuation in the rotation speed of a second wheel on a rear side of the vehicle occurs, the determination unit determines that an uneven portion is formed on the road surface at a position on a trajectory of the first wheel and the second wheel when the time difference corresponds to a moving period during which the vehicle moves by an amount corresponding to a wheelbase of the vehicle; and The information processing device, wherein the determination unit determines that, when the fluctuation state of the rotational speeds of the first wheel and the second wheel continues, either a ridge portion or a groove portion in which the uneven portion is continuous along the locus is formed on the road surface.

2. An information processing device for acquiring information regarding a road surface on which a vehicle is traveling, A detection unit that detects fluctuations in the rotational speed of each wheel of the vehicle; a determination unit that determines the road surface condition based on a determination result of whether fluctuations in the rotation speeds of the left and right wheels of the vehicle are synchronized and a time difference between a time point when a fluctuation in the rotation speed of a first wheel on a front side of the vehicle occurs and a time point when a fluctuation in the rotation speed of a second wheel on a rear side of the vehicle occurs, The information processing device, wherein the determination unit determines that a step crossing the road surface has formed on the road surface when fluctuations in the rotational speed of the left and right wheels are synchronized and the time difference corresponds to a travel period in which the vehicle moves an amount equal to the wheelbase of the vehicle.

3. 3. The information processing device according to claim 2, wherein the determination unit determines that an undulation formed by a plurality of steps on the road surface has formed on the road surface when fluctuations in the rotational speeds of the left and right wheels are synchronized and the time difference is determined to correspond to the movement period multiple times.

4. The information processing device according to claim 1 , further comprising a transmission unit configured to transmit the road surface condition determined by the determination unit and position information of the road surface to an external server.

5. A vehicle equipped with an information processing device that acquires information about a road surface on which the vehicle is traveling, The information processing device includes: A detection unit that detects fluctuations in the rotational speed of each wheel of the vehicle; a determination unit that determines the road surface condition based on a result of a determination as to whether fluctuations in the rotation speeds of the left and right wheels of the vehicle are synchronized or not, and a time difference between a time point when a fluctuation in the rotation speed of a first wheel on a front side of the vehicle occurs and a time point when a fluctuation in the rotation speed of a second wheel on a rear side of the vehicle occurs, the determination unit determines that an uneven portion is formed on the road surface at a position on a trajectory of the first wheel and the second wheel when the time difference corresponds to a moving period during which the vehicle moves by an amount corresponding to a wheelbase of the vehicle; and The vehicle, wherein the determination unit determines that, when the fluctuation state of the rotational speeds of the first wheel and the second wheel continues, either a ridge portion or a groove portion in which the uneven portion is continuous along the locus is formed on the road surface.

6. A vehicle equipped with an information processing device that acquires information regarding a road surface on which the vehicle is traveling, The information processing device includes: A detection unit that detects fluctuations in the rotational speed of each wheel of the vehicle; a determination unit that determines the road surface condition based on a result of a determination as to whether fluctuations in the rotation speeds of the left and right wheels of the vehicle are synchronized or not, and a time difference between a time point when a fluctuation in the rotation speed of a first wheel on a front side of the vehicle occurs and a time point when a fluctuation in the rotation speed of a second wheel on a rear side of the vehicle occurs, The determination unit determines that a step crossing the road surface has formed on the road surface when fluctuations in the rotational speed of the left and right wheels are synchronized and the time difference corresponds to a travel period in which the vehicle moves an amount equal to the wheelbase of the vehicle.

7. An information processing device that acquires information about a road surface on which a vehicle is traveling; a server for managing information transmitted from the information processing device; The information processing device includes: A detection unit that detects fluctuations in the rotational speed of each wheel of the vehicle; a determination unit that determines the road surface condition based on a result of a determination as to whether fluctuations in the rotation speeds of the left and right wheels of the vehicle are synchronized or not, and a time difference between a time point when a fluctuation in the rotation speed of a first wheel on a front side of the vehicle occurs and a time point when a fluctuation in the rotation speed of a second wheel on a rear side of the vehicle occurs, the determination unit determines that an uneven portion is formed on the road surface at a position on a trajectory of the first wheel and the second wheel when the time difference corresponds to a moving period during which the vehicle moves by an amount corresponding to a wheelbase of the vehicle; and The information processing system, wherein the determination unit determines that, when the fluctuation state of the rotational speeds of the first wheel and the second wheel continues, either a ridge or a groove portion in which the uneven portion is continuous along the locus is formed on the road surface.

8. An information processing device that acquires information regarding a road surface on which a vehicle is traveling; a server for managing information transmitted from the information processing device; The information processing device includes: A detection unit that detects fluctuations in the rotational speed of each wheel of the vehicle; a determination unit that determines the road surface condition based on a result of a determination as to whether fluctuations in the rotation speeds of the left and right wheels of the vehicle are synchronized or not, and a time difference between a time point when a fluctuation in the rotation speed of a first wheel on a front side of the vehicle occurs and a time point when a fluctuation in the rotation speed of a second wheel on a rear side of the vehicle occurs, The information processing system, wherein the determination unit determines that a step crossing the road surface has formed on the road surface when fluctuations in the rotational speed of the left and right wheels are synchronized and the time difference corresponds to a travel period in which the vehicle moves an amount equal to the wheelbase of the vehicle.

9. An information processing method for acquiring information about a road surface on which a vehicle is traveling, comprising: detecting fluctuations in rotational speed of each wheel of the vehicle; determining the road surface condition based on a result of determining whether fluctuations in the rotation speeds of the left and right wheels of the vehicle are synchronized and a time difference between a time point when a fluctuation in the rotation speed of a first wheel on the front side of the vehicle occurs and a time point when a fluctuation in the rotation speed of a second wheel on the rear side of the vehicle occurs; determining that an uneven portion is formed on the road surface at a position on a trajectory of the first wheel and the second wheel when the time difference corresponds to a moving period during which the vehicle moves by an amount corresponding to a wheelbase of the vehicle; and if the fluctuation in the rotational speeds of the first wheel and the second wheel continues, determining that the uneven portion is formed on the road surface as either a ridge or a groove that continues along the locus.

10. An information processing method for acquiring information about a road surface on which a vehicle is traveling, comprising: detecting fluctuations in rotational speed of each wheel of the vehicle; determining the road surface condition based on a result of determining whether fluctuations in the rotation speeds of the left and right wheels of the vehicle are synchronized and a time difference between a time point when a fluctuation in the rotation speed of a first wheel on the front side of the vehicle occurs and a time point when a fluctuation in the rotation speed of a second wheel on the rear side of the vehicle occurs; and determining that a step crossing the road surface has formed on the road surface when the fluctuations in the rotational speeds of the left and right wheels are synchronized and the time difference corresponds to a period of travel during which the vehicle moves an amount equal to the wheelbase of the vehicle.

11. On the computer, Detecting fluctuations in rotational speed of each wheel of a vehicle traveling on a road surface; determining the road surface condition based on a result of determining whether fluctuations in the rotation speeds of the left and right wheels of the vehicle are synchronized and a time difference between a time point when a fluctuation in the rotation speed of a first wheel on the front side of the vehicle occurs and a time point when a fluctuation in the rotation speed of a second wheel on the rear side of the vehicle occurs; determining that an uneven portion is formed on the road surface at a position on a trajectory of the first wheel and the second wheel when the time difference corresponds to a moving period during which the vehicle moves by an amount corresponding to a wheelbase of the vehicle; and if the fluctuation in the rotational speeds of the first wheel and the second wheel continues, determining that the uneven portion is formed on the road surface as either a ridge or a groove that continues along the locus.

12. A computer comprising: Detecting fluctuations in rotational speed of each wheel of a vehicle traveling on a road surface; determining the road surface condition based on a result of determining whether fluctuations in the rotation speeds of the left and right wheels of the vehicle are synchronized and a time difference between a time point when a fluctuation in the rotation speed of a first wheel on the front side of the vehicle occurs and a time point when a fluctuation in the rotation speed of a second wheel on the rear side of the vehicle occurs; and determining that a step crossing the road surface has formed on the road surface when the fluctuations in the rotational speeds of the left and right wheels are synchronized and the time difference corresponds to a period of travel during which the vehicle moves by the wheelbase of the vehicle.

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