JP7694482B2 - Road surface condition information system - Google Patents

Description

The present invention relates to a road surface condition information providing system. In particular, the present invention relates to an improvement for providing information on road surface deterioration at an early stage.

A conventional system for detecting road surface conditions is disclosed in Patent Document 1. The system disclosed in Patent Document 1 detects road surface conditions such as deterioration while patrolling a road with a patrol car equipped with a camera, G sensor, microphone, and GPS unit.

Specifically, abnormalities in the pavement of the road surface are detected from the road surface on the road image captured by the camera. Furthermore, abnormalities in the pavement of the road surface are detected from the acceleration measured by the G sensor while driving. Furthermore, abnormalities in the pavement of the road surface are detected from the voice data recorded by the microphone while driving on the road surface. Then, the position where the abnormality in the pavement was detected is identified using one or two of the detection information from the road image, acceleration, and voice data, and an instruction to reinvestigate this identified position is output.

JP 2013-139671 A

However, the system disclosed in Patent Document 1 identifies abnormalities by performing a simple inspection using a patrol vehicle that patrols, and then re-inspecting the location where an abnormality (deterioration to the extent that repair is required) was detected. This makes it difficult to repeatedly perform the operation of detecting the road surface condition (the operation of detecting the degree of deterioration of the road surface) on the same road within a relatively short period of time, and there is a possibility that there will be a delay in the timing of obtaining information about an abnormality in the road surface (abnormality in the pavement). In other words, there is a possibility that there will be a delay in the timing of repairing the road. As a result, the abnormality in the road surface will be left unattended for a long period of time, which may lead to problems such as adversely affecting the ride comfort of vehicles traveling on that road surface during that period.

The present invention was made in consideration of these points, and its purpose is to realize a road surface condition information providing system that can obtain and provide information on road surface deterioration at an early stage.

The solution of the present invention for achieving the above object is based on a road surface condition information providing system that provides information on the deterioration state of a road surface. The road surface condition information providing system is configured to include a plurality of general vehicles and an information collecting device capable of communicating with the plurality of general vehicles. Each of the general vehicles is equipped with a position detection means for detecting a vehicle position, a measurement means for measuring a parameter value that changes due to a change in the contact state between the steering wheel and the road surface, and a driving information transmitting unit for transmitting driving information that associates information on the vehicle position detected by the position detection means with information on the parameter value measured by the measurement means at the vehicle position or road surface deterioration judgment information based on the parameter value. The information collection device further comprises an information receiving unit that receives the driving information transmitted from the driving information transmitting unit of each of the general vehicles, a deterioration index creation unit that creates a deterioration index of the road surface condition for each position of the road surface based on the multiple driving information received by the information receiving unit, a road surface deterioration estimation information creation unit that creates road surface deterioration estimation information that associates the deterioration index information created by the deterioration index creation unit with position information of the road surface corresponding to the information, and a road surface deterioration estimation information providing unit that provides the road surface deterioration estimation information, wherein the parameter that changes due to a change in the contact condition between the steered wheel and the road surface is a current value of an electric assist motor provided in an electric power steering device, and the measuring means is a current sensor that measures the current value .

The "general vehicle" referred to here is a vehicle other than the aforementioned patrol vehicle, which is specialized in detecting the deterioration state of road surfaces, and is a vehicle in which a general user rides (e.g., traveling toward a specific destination).

If the road surface is deteriorated (for example, when ruts exist), when a general vehicle passes over the road surface (for example, when the steering wheel enters the rut), the value of the parameter (the parameter that changes due to the change in the contact state between the steering wheel and the road surface) changes due to the change in the contact state between the steering wheel of the vehicle and the road surface, and this is measured by the measurement means. In addition, since the general vehicle detects its own vehicle position by the position detection means, the driving information transmitting unit transmits to the information collecting device driving information that associates the information of the own vehicle position with the information of the parameter value measured at the own vehicle position (or driving information that associates the information of the own vehicle position with road surface deterioration judgment information based on the parameter value measured at the own vehicle position). In the information collecting device, the information receiving unit receives a plurality of pieces of driving information, and the deterioration index creating unit creates a deterioration index of the road surface state for each position of the road surface based on the driving information. Then, the road surface deterioration estimation information creating unit creates road surface deterioration estimation information that associates the information of the deterioration index with the position information of the road surface corresponding to the information. This road surface deterioration estimation information is provided by a road surface deterioration estimation information providing unit (for example, provided to a road administrator, a road repair judging unit that receives the road surface deterioration estimation information and judges whether or not road repair (road surface repair) is necessary, etc.). By receiving this road surface deterioration estimation information, it is possible to easily judge whether or not road repair is necessary. In this way, since the road surface deterioration estimation information created based on the driving information transmitted from each of a plurality of general vehicles is provided, it is possible to provide information on road surface deterioration earlier than a method of detecting the road surface condition by patrolling a dedicated patrol car, and as a result, a delay in the timing of obtaining information on the occurrence of an abnormality in the road surface is suppressed, and a delay in the timing of road repair can be avoided.
Furthermore, when the steering wheel is forcibly steered (turned) due to the influence of the ruts (so-called a situation where the steering wheel is taken), the driver applies a steering force (steering force) to the steering wheel to counter the steering force that causes the forcible steering. Therefore, in the electric power steering device, the electric assist motor operates to generate an assist force for this steering force, and the current value (motor current value) temporarily increases. The deeper the ruts are, the greater the steering force required, and the higher the motor current value is. In other words, there is a correlation between the depth of the ruts and the motor current value. Therefore, by setting the parameter as the current value of the electric assist motor and measuring the current value with a current sensor, it is possible to obtain driving information according to the depth of the ruts, and to obtain a deterioration index of the road surface condition with high accuracy.

In addition, when the value of the parameter exceeds a predetermined threshold, the driving information transmitting unit transmits driving information that associates the vehicle position information from which the parameter value was obtained with road surface deterioration determination information based on the parameter value.

As a result, when the parameter value exceeds a predetermined threshold value due to deterioration of the road surface, the driving information is transmitted from the driving information transmission unit to the information collection device, so that the information transmitted to the information collection device can be narrowed down to only useful information, thereby making the use of information more efficient and reducing the load on the information collection device.

In addition, when the amount of change in the value of the parameter per unit time exceeds a predetermined threshold, the driving information transmitting unit transmits driving information that associates information on the vehicle position where the amount of change exceeds the predetermined threshold with road surface deterioration determination information based on the amount of change.

As a result, when the contact condition between the steered wheels and the road surface changes significantly and the amount of change in the parameter value per unit time exceeds a predetermined threshold, the driving information is transmitted from the driving information transmission unit to the information collection device, so that in this case too, it is possible to increase the efficiency of information use and reduce the load on the information collection device.

Another solution of the present invention for achieving the above object is based on a road surface condition information providing system that provides information on the deterioration state of a road surface. This road surface condition information providing system is configured to include a plurality of general vehicles and an information collecting device capable of communicating with the plurality of general vehicles. Each of the general vehicles is equipped with a position detection means for detecting a vehicle position, a measurement means for measuring a parameter value that changes due to a change in the contact state between the steering wheel and the road surface, and a driving information transmission unit for transmitting driving information that associates information on the vehicle position detected by the position detection means with information on the parameter value measured by the measurement means at the vehicle position or road surface deterioration judgment information based on the parameter value. The information collection device further comprises an information receiving unit that receives the driving information transmitted from the driving information transmitting unit of each of the general vehicles, a deterioration index creation unit that creates a deterioration index of the road surface condition for each position of the road surface based on the multiple driving information received by the information receiving unit, a road surface deterioration estimation information creation unit that creates road surface deterioration estimation information that associates the deterioration index information created by the deterioration index creation unit with position information of the road surface corresponding to the information, and a road surface deterioration estimation information providing unit that provides the road surface deterioration estimation information, wherein the parameter that changes due to a change in the contact condition between the steering wheel and the road surface is the rotation angle of an electric assist motor provided in an electric power steering device, and the measuring means is a motor rotation angle sensor that measures the rotation angle .

When the steering wheels are forcibly steered due to the influence of the ruts, the rotor of the electric assist motor is also forcibly rotated. The deeper the ruts, the greater the rotation angle of the electric assist motor (the rotation angle at which it is forcibly rotated). In other words, there is a correlation between the depth of the ruts and the rotation angle of the electric assist motor. For this reason, by setting the parameter as the rotation angle of the electric assist motor and measuring this rotation angle with a motor rotation angle sensor, it is possible to obtain driving information according to the depth of the ruts.

Another solution of the present invention for achieving the above object is based on a road surface condition information providing system that provides information on the deterioration state of a road surface. This road surface condition information providing system is configured to include a plurality of general vehicles and an information collecting device capable of communicating with the plurality of general vehicles. Each of the general vehicles is equipped with a position detection means for detecting a vehicle position, a measurement means for measuring a parameter value that changes due to a change in the contact state between the steering wheel and the road surface, and a driving information transmission unit for transmitting driving information that associates information on the vehicle position detected by the position detection means with information on the parameter value measured by the measurement means at the vehicle position or road surface deterioration judgment information based on the parameter value. The information collection device further comprises an information receiving unit that receives the driving information transmitted from the driving information transmitting unit of each of the general vehicles, a deterioration index creation unit that creates a deterioration index of the road surface condition for each position of the road surface based on the multiple driving information received by the information receiving unit, a road surface deterioration estimation information creation unit that creates road surface deterioration estimation information that associates the deterioration index information created by the deterioration index creation unit with position information of the road surface corresponding to the information, and a road surface deterioration estimation information providing unit that provides the road surface deterioration estimation information, wherein the parameter that changes due to a change in the contact condition between the steering wheel and the road surface is the difference in the steering angle of each of the left and right steering wheels when each of the left and right steering wheels can be steered independently, and the measuring means is a steering angle sensor that measures the steering angle of each of the left and right steering wheels .

When one of the steered wheels is forcibly steered due to the influence of ruts, the steering angle of that wheel increases, resulting in a difference between the steering angles of the left and right steered wheels, and this difference increases the deeper the ruts are. In other words, there is a correlation between the depth of the ruts and the difference in the steering angles of each steered wheel. For this reason, by setting the parameter as the difference in the steering angles of each steered wheel and measuring the difference in steering angles using a steering angle sensor, it is possible to obtain driving information according to the depth of the ruts.

The road surface deterioration estimation information providing unit also transmits the road surface deterioration estimation information to a terminal device monitored by a road administrator.

This allows road managers to receive road surface deterioration estimation information via the terminal device, making it easier to determine whether road repairs are necessary.

The road surface deterioration estimation information providing unit also transmits the road surface deterioration estimation information to a road repair determination unit that determines the need for road repairs by machine learning through a comparison between the provided road surface deterioration estimation information and pre-stored teacher information for the road surface deterioration estimation information.

This allows the need for road repairs to be determined automatically through machine learning, reducing the burden on road managers and preventing road surfaces from being left in a deteriorated state (in need of repairs) for long periods of time due to incorrect judgment on the part of the road manager.

In the present invention, a deterioration index of the road surface condition is created for each road surface position based on driving information collected from multiple general vehicles, and road surface deterioration estimation information is provided that associates this deterioration index information with the road surface position information corresponding to the information. Therefore, it is possible to provide information on road surface deterioration earlier than by having a dedicated patrol car patrol the road surface condition, and as a result, delays in obtaining information on abnormalities in the road surface are suppressed, and delays in the timing of road repairs can be avoided.

1 is a diagram showing a schematic configuration of a road surface condition information providing system according to an embodiment; FIG. 4 is a diagram showing an example of a relationship between a tire steering angle and a motor current value. FIG. 2 is a diagram showing a state in which a tire is stuck in a rut. FIG. 11 is a diagram illustrating an example of a relationship between a rut depth and a motor current value. The figures show the tire contact conditions on the road, with FIG. 5(a) showing a driving condition in which each of the left and right tires is in the center of the rut, and FIG. 5(b) showing a driving condition in which each of the left and right tires is in contact with the outside of the rut. 6 is a diagram showing an example of a transition of a motor current value in the state shown in FIG. 5 . The figures show the tire contact conditions on the road, with Figure 7(a) showing a driving state in which the left tire gets into the center of the rut and the inner part of the right tire is in contact with the sloping surface of the rut, Figure 7(b) showing a driving state in which the outer part of the left tire and the inner part of the right tire are each in contact with the sloping surface of the rut, Figure 7(c) showing a driving state in which the outer part of the left tire is in contact with the sloping surface of the rut and the right tire is in contact with the outside of the rut, and Figure 7(d) showing a driving state in which the left tire gets into the center of the rut and the right tire is in contact with the outside of the rut. FIG. 13 is a diagram showing an example of a change in motor current value when a rightward steering correction is made when entering a rut. FIG. 11 is a diagram showing an example of a change in motor current value when the vehicle is steered rightward for a predetermined period of time while traveling through ruts. The figures show the tire contact conditions on the road, with Figure 10(a) showing a driving state in which the inner part of the left tire is in contact with the sloping surface of the rut and the right tire is in the center of the rut, Figure 10(b) showing a driving state in which the inner part of the left tire and the outer part of the right tire are each in contact with the sloping surface of the rut, Figure 10(c) showing a driving state in which the left tire is in contact with the outside of the rut and the outer part of the right tire is in contact with the sloping surface of the rut, and Figure 10(d) showing a driving state in which the left tire is in contact with the outside of the rut and the right tire is in the center of the rut. FIG. 13 is a diagram showing an example of a change in motor current value when the vehicle is steered leftward when entering a rut; FIG. 11 is a diagram showing an example of a change in motor current value when the vehicle is steered leftward for a predetermined period of time while traveling through ruts. The figures show the tire contact conditions on the road, with Figure 13(a) showing a driving state in which the inner side of the left tire and the inner side of the right tire are in contact with the sloping surface of the rut, Figure 13(b) showing a driving state in which the outer side of the left tire and the outer side of the right tire are in contact with the sloping surface of the rut, Figure 13(c) showing a driving state in which the inner side of the left tire is in contact with the sloping surface of the rut and the right tire is in contact with the outside of the rut, and Figure 13(d) showing a driving state in which the left tire is in contact with the outside of the rut and the inner side of the right tire is in contact with the sloping surface of the rut. FIG. 14 is a diagram showing an example of a change in motor current value in any one of the states shown in FIGS. 13( a ) to 13 ( d ). FIG. 11 is a diagram showing an example of a change in motor current value during a period from when a tire enters a rut until when the tire exits the rut. FIG. 11 is a diagram showing an example of a first map display state on a display screen of an administrator terminal device. FIG. 13 is a diagram showing an example of a second map display state on the display screen of the administrator terminal device. FIG. 4 is a sequence diagram showing an example of the operation of each of a vehicle, a data center, and an administrator terminal device. FIG. 13 is a diagram showing a schematic configuration of a road surface condition information providing system according to a modified example.

The following describes an embodiment of the present invention with reference to the drawings. This embodiment describes an example in which a road surface condition information providing system according to the present invention is constructed using a rack-assist type electric power steering device.

- Overview of the road surface condition information system -
Fig. 1 is a diagram showing a schematic configuration of a road surface condition information providing system 1 according to this embodiment. As shown in Fig. 1, the road surface condition information providing system 1 includes an electric power steering device EPS mounted on each of a plurality of vehicles V, V, ..., a data center (information collecting device) DS, and an administrator terminal device ATE. The data center DS and the administrator terminal device ATE are installed in, for example, a road management organization (for example, a construction bureau of a local government or a road repair company). The electric power steering device EPS, the data center DS, and the administrator terminal device ATE are configured to be able to communicate with each other using a predetermined communication network CN.

The communication form between the electric power steering device EPS, the data center DS, and the administrator terminal device ATE is a two-way communication form through a mobile phone network having many base stations, an Internet network, a dedicated communication network, etc. The communication form between the electric power steering device EPS and the data center DS is a two-way communication form through a mobile phone network, an Internet network, a dedicated communication network, etc., while the communication form between the data center DS and the administrator terminal device ATE may be a two-way communication form through a dedicated communication line.

The following describes the electric power steering device EPS, data center DS, and administrator terminal device ATE.

(Electric power steering device)
The electric power steering device EPS mounted on each of the vehicles V, V, ... will be described. In Fig. 1, the configuration of the part related to the road surface condition information providing system 1 is shown by taking the electric power steering device EPS mounted on one vehicle V as a representative.

As shown in FIG. 1, the electric power steering system EPS includes a steering mechanism (steering device) 10 for steering (maneuvering) the left front wheel T1 (hereinafter sometimes referred to as the left tire) and the right front wheel T2 (hereinafter sometimes referred to as the right tire), which are steered wheels (also called turning wheels).

The steering mechanism 10 has a steering wheel 11, a steering shaft 12 connected to the steering wheel 11, and a rack bar 14.

The steering mechanism 10 converts the rotation of the steering shaft 12 around its axis, which is linked to the rotation of the steering wheel 11, into a left-right stroke motion (linear motion) of the rack bar 14 by the rack-and-pinion mechanism 13. The stroke motion of the rack bar 14 steers the left front wheel T1 and right front wheel T2, which are the steered wheels.

The steering shaft 12 includes a main shaft 12a, the upper end of which is connected to the steering wheel 11, a pinion shaft 12c, which is connected to the rack and pinion mechanism 13, and an intermediate shaft 12b, which connects the main shaft 12a and the pinion shaft 12c via universal joints 12d and 12e.

The rack bar 14 has a gear portion 14a formed near the center of the rack bar 14. The center portion of the rack bar 14 is housed in the rack housing 15. The left and right ends of the rack bar 14 protrude from the rack housing 15 and are connected to one end of each of the left and right tie rods 16. The other ends of each of the left and right tie rods 16 are connected to knuckles 17 provided on the left front wheel T1 and the right front wheel T2, respectively. A rack end member 18 is provided at the connection between the rack bar 14 and the tie rod 16. Meanwhile, a stopper portion 15a is formed on both ends of the rack housing 15. When the rack bar 14 strokes in the axial direction by a predetermined amount or more, the rack end member 18 comes into contact with the stopper portion 15a. This limits the stroke range of the rack bar 14.

The electric assist motor 21, which is the power source of the electric power steering device EPS, is composed of a three-phase synchronous permanent magnet motor (three-phase brushless motor). The electric assist motor 21 includes a rotor, both not shown, and a stator that is fixed in a housing supported by the vehicle body and faces the rotor. A rotating shaft, not shown, that rotates integrally with the rotor can transmit power to the rack bar 14 via a reduction gear 19.

The steering ECU 20, which constitutes the control system of the electric power steering device EPS, includes, for example, a processor such as a CPU (Central Processing Unit), a ROM (Read-Only Memory) that stores control programs, a RAM (Random-Access Memory) that temporarily stores data, and input/output ports.

The steering ECU 20 is connected to a motor rotation angle sensor 22, a steering force sensor 23, a steering angle sensor 24, a wheel speed sensor 25, a current sensor (measurement means) 34, a G sensor 26, and a GPS module (position detection means) 27 via signal lines.

The motor rotation angle sensor 22 is incorporated inside the electric assist motor 21 and outputs a signal representing the rotation angle of the rotor of the electric assist motor 21. This motor rotation angle sensor 22 is composed of, for example, a resolver or a hall sensor. The angular velocity and rotation speed of the electric assist motor 21 are obtained from the signal representing the rotation angle. In addition, the electrical angle of the electric assist motor 21 is obtained from the signal representing the rotation angle.

The steering force sensor 23 is provided on the steering shaft 12 (main shaft 12a). The steering force sensor 23 detects the torsional force input to a torsion bar (not shown) that is attached to the steering shaft 12 as the steering force.

The steering angle sensor 24 detects the steering angle of the steering wheel 11 and outputs a signal representing the steering angle.

The wheel speed sensor 25 detects the rotational speed of each wheel T1, T2 and outputs a signal representing these rotational speeds.

The current sensor 34 detects the value of the current (hereinafter referred to as the motor current value) flowing through the coil of the electric assist motor 21 and outputs a signal representing the motor current value (a parameter that changes due to changes in the contact state between the steering wheel and the road surface, as referred to in this invention).

Now, we will explain the change in the motor current value. Figure 2 is a diagram showing an example of the relationship between the tire steering angle and the motor current value. This figure shows an example of the relationship between the tire steering angle (for example, the tire steering angle caused by the driver turning the steering wheel 11) and the motor current value in a range where the tire steering angle is relatively small. The thin line in this figure shows the relationship between the tire steering angle and the motor current value when the vehicle V is traveling on a flat road (a road surface without ruts, etc.). In this case, as the tire steering angle increases (such as when traveling on a curved road and the curvature of the road increases), the motor current value gradually increases so as to obtain a larger assist force (assist force for steering force) from the electric assist motor 21.

On the other hand, when the vehicle V is traveling on a road surface with ruts or the like (a deteriorated road surface), when the tire (steered wheel) enters the rut from a flat road, when the tire contacts the inclined surface inside the rut, or when the tire exits the rut onto a flat road, the tire is forced to steer (turn) due to the influence of the rut (leading to a situation where the steering wheel is taken away). At this time, the driver (for example, a driver who is trying to maintain straight driving) applies a steering force (hereinafter sometimes referred to as a steering force) to the steering wheel 11 that counters the steering force that forces the steering. In other words, steering is performed in the opposite direction to the forced steering direction. For this reason, the electric assist motor 21 operates to generate an assist force for the steering force in the opposite direction. In other words, the motor current value temporarily increases so that this assist force is generated. The thick line in FIG. 2 shows an example of a change in the motor current value accompanying the generation of this assist force. In such a situation, a change in the motor current value appears that differs from the normal motor current value (the motor current value shown by the thin line in Figure 2) that corresponds to the tire steering angle. In other words, when such a change in the motor current value appears, it can be determined that a rut is present on the road surface.

Figure 3 shows a state in which the tire T has entered the rut WT. Also, Figure 4 shows an example of the relationship between the depth of the rut WT and the motor current value. Figure 3 shows a number of ruts WT with different depths, with the depth increasing in the order of solid line, dashed line, and dashed line. As shown in Figure 4, the relationship between the depth of the rut WT and the motor current value is such that the deeper the rut WT, the greater the change in the motor current value. In Figure 4, the depth increases in the order of solid line, dashed line, and dashed line. This is because the deeper the rut WT, the closer the inclination angle of the inclined surface inside the rut WT becomes to the vertical direction. In other words, the closer the inclination angle of the inclined surface inside the rut WT is to the vertical direction, the greater the steering force that forcibly steers the tire T when it is in contact with the inclined surface, and the greater the steering force that the driver applies to the steering wheel 11 in opposition to this, and as a result, the greater the change in the motor current value becomes as the depth of the rut WT increases.

The G sensor 26 detects the vertical and horizontal accelerations generated in the vehicle and outputs the acceleration signals. In addition, the sensors that detect the behavior of the vehicle V are not limited to this, and may include a G sensor that detects the acceleration in the forward and backward directions and a yaw rate sensor that detects the yaw rate.

The GPS module 27 receives signals from GPS satellites to measure the position of the vehicle and output the measurement result, which is vehicle position information.

The steering ECU 20 is connected to the motor drive circuit 30 and sends a command signal to the motor drive circuit 30. The motor drive circuit 30 has a well-known configuration for performing well-known motor vector control. The motor drive circuit 30 drives the electric assist motor 21 with power supplied from the on-board power supply 33 based on the command signal from the steering ECU 20.

In addition, the steering ECU 20 includes an information receiving unit 28, a rut determining unit 29, and a driving information transmitting unit 20A as functional units realized by the control program. The following is an outline of the functions of each of these units.

The information receiving unit 28 is capable of receiving information on the motor current value (the current value flowing through the coil of the electric assist motor 21) detected by the current sensor 34, and information on the vehicle's position measured by the GPS module 27.

The rut determination unit 29 is a functional unit that determines whether or not a rut WT exists on the road surface based on the motor current value. In this embodiment, the rut determination unit 29 determines that a rut WT exists (the rut determination flag is ON) when the motor current value exceeds a predetermined threshold value.

Below, we will explain several patterns regarding the relationship between the road contact state of the tires when the vehicle V is traveling, the corresponding forced steering force generated in the tires (steering force generated due to a reaction force from the road surface), and the motor current value for generating an assist force for steering force.

First, FIG. 5 shows the road contact state of tires T1, T2 when vehicle V travels from the front side of the page to the back side. FIG. 5(a) shows the running state in which each of left and right tires T1, T2 is in the center of the wheel rut WT, and FIG. 5(b) shows the running state in which each of left and right tires T1, T2 is in contact with the outside of the wheel rut WT.

In the cases shown in these figures, tires T1 and T2 are not affected by the rut WT, and no forced steering force is generated. Therefore, no steering force is generated. As a result, in these cases, the motor current value remains at zero, as shown in Figure 6. In this Figure 6, the upward direction of the vertical axis represents the magnitude of the steering assist force to the right, and the downward direction of the vertical axis represents the magnitude of the steering assist force to the left.

Figure 7 shows the tire contact state when the vehicle V travels from the front side to the back side of the page, and Figure 7(a) shows a running state in which the left tire (left front wheel) T1 enters the center of the rut WT and the inside part of the right tire (right front wheel) T2 contacts the slope of the rut WT. Figure 7(b) shows a running state in which the outside part of the left tire T1 and the inside part of the right tire T2 each contact the slope of the rut WT. Figure 7(c) shows a running state in which the outside part of the left tire T1 contacts the slope of the rut WT and the right tire T2 contacts the outside of the rut WT. Figure 7(d) shows a running state in which the left tire T1 enters the center of the rut WT and the right tire T2 contacts the outside of the rut WT.

In the states shown in Figures 7(a) to 7(c), a forced steering force is generated in the direction that causes at least one of the tires to run up the slope of the rut WT, so a forced steering force is generated to the left. Also, in the state shown in Figure 7(d), the height position of the left tire T1 is lower than the height position of the right tire T2 by the depth of the rut WT, so in this case too, a forced steering force is generated to the left.

In the cases shown in these figures, tires T1 and T2 are affected by the wheel rut WT, and a forced steering force to the left is generated, so the driver corrects the steering to apply a steering force to the right to counter this forced steering force. This causes a motor current to be generated to generate an assist force for this steering force to the right (assist force to the right). As a result, in these cases, the motor current value changes as shown in FIG. 8. In particular, in the state shown in FIG. 7(d), a forced steering force is continuously generated while the left tire T1 is in the center of the wheel rut WT, so a steering force to the right is also continuously generated, and an assist force for the steering force is also continuously generated, so the motor current value changes as shown in FIG. 9.

Figure 10 also shows the tire contact state when the vehicle V travels from the front side to the back side of the page, with Figure 10(a) showing a running state in which the inside part of the left tire T1 contacts the slope of the rut WT and the right tire T2 is in the center of the rut WT. Figure 10(b) shows a running state in which the inside part of the left tire T1 and the outside part of the right tire T2 each contact the slope of the rut WT. Figure 10(c) shows a running state in which the left tire T1 contacts the outside of the rut WT and the outside part of the right tire T2 contacts the slope of the rut WT. Figure 10(d) shows a running state in which the left tire T1 contacts the outside of the rut WT and the right tire T2 is in the center of the rut WT.

Even in the state shown in Figures 10(a) to 10(c), a forced steering force is generated in the direction that causes at least one tire to run up the slope of the rut WT, so a forced steering force to the right is generated, opposite to the state shown in Figures 7(a) to 7(c) described above. Also, in the state shown in Figure 10(d), the height position of the right tire T2 is lower than the height position of the left tire T1 by the depth of the rut WT, so in this case too, a forced steering force to the right is generated.

In the cases shown in these figures, tires T1 and T2 are affected by the wheel rut WT, and a forced steering force to the right is generated, and the driver corrects the steering to apply a steering force to the left to counter this forced steering force. This causes a motor current to be generated to generate an assist force for this steering force to the left (assist force to the left). As a result, in these cases, the motor current value changes as shown in FIG. 11. In particular, in the state shown in FIG. 10(d), a forced steering force is continuously generated while the right tire T2 is in the center of the wheel rut WT, so a steering force to the left is also continuously generated, and an assist force for the steering force is also continuously generated, and the motor current value changes as shown in FIG. 12.

Furthermore, FIG. 13 shows the road contact state of tires T1, T2 when vehicle V travels from the front side to the back side of the page, and FIG. 13(a) shows a traveling state in which the inner side of left tire T1 and the inner side of right tire T2 are in contact with the slope of rut WT. FIG. 13(b) shows a traveling state in which the outer side of left tire T1 and the outer side of right tire T2 are in contact with the slope of rut WT. FIG. 13(c) shows a traveling state in which the inner side of left tire T1 is in contact with the slope of rut WT and right tire T2 is in contact with the outside of rut WT. FIG. 13(d) shows a traveling state in which left tire T1 is in contact with the outside of rut WT and the inner side of right tire T2 is in contact with the slope of rut WT.

Even in the states shown in Figures 13(a) to 13(d), a forced steering force is generated in the direction in which the tires run up the slope of the rut WT. However, in the state shown in Figure 13(a), a forced steering force to the right is generated in the left tire T1, while a forced steering force to the left is generated in the right tire T2. In the state shown in Figure 13(b), a forced steering force to the left is generated in the left tire T1, while a forced steering force to the right is generated in the right tire T2. In the state shown in Figure 13(c), a forced steering force to the right is generated in the left tire T1, while a forced steering force to the left is generated because the height position of the left tire T1 is lower than the height position of the right tire T2 by the depth of the rut WT. In the situation shown in FIG. 13(d), a forced steering force to the left is generated in the right tire T2, but because the height position of the right tire T2 is lower than the height position of the left tire T1 by the depth of the rut WT, a forced steering force to the right is generated. In other words, in the situations shown in FIG. 13(a) to FIG. 13(d), the forced steering force is unstable, and the driver's steering force is also unstable. For this reason, the motor current value for generating an assist force for the steering force is also unstable. As a result, in these cases, the motor current value transitions in an unstable state, as shown in FIG. 14, for example.

Figure 15 is a diagram showing an example of the change in motor current value during the period from when tires T1 and T2 enter the rut WT until they exit the rut WT. In this figure, at timing t1 in the figure, one tire enters the rut WT, and the motor current value rises temporarily accordingly. In the example shown in Figure 15, the motor current value rises so that the assist force to the right side increases, so for example, the state shown in Figure 7(b) is assumed. In addition, in the period from timing t2 to timing t3 in the figure, the motor current value is in an unstable state. In the example shown in Figure 15, the motor current value rises so that the assist force to the left side increases in the period from timing t2 to timing t3, so for example, the state shown in Figure 13(c) is assumed. In addition, at timing t4 in the figure, one tire that entered the rut WT exits the rut WT, and the motor current value rises temporarily accordingly. In the example shown in Figure 15, the motor current value increases so that the assist force to the right side increases during this escape, so it is assumed that the left tire T1 has escaped from the state shown in Figure 13(c), for example.

The rut determination unit 29 utilizes the fact that the motor current value changes due to the presence of ruts WT as described above, and when the motor current value exceeds a predetermined threshold, determines that a rut WT is present (a rut WT of a predetermined depth or greater is present), and transmits a determination signal (a determination signal indicating that a rut WT is present and a signal related to the size of the rut WT) to the driving information transmission unit 20A.

The method for determining whether or not a wheel rut WT is present is described in detail below. This method determines whether or not a wheel rut WT is present based on the deviation from the motor current value for obtaining the assist force from the electric assist motor 21 when no wheel rut WT is present (the increase in the motor current value for obtaining the assist force for the steering force).

In other words, when the vehicle V is traveling straight (the steering angle of the steering wheel 11 is approximately zero), the assist force from the electric assist motor 21 is approximately zero and the motor current value is also approximately zero, so if the increase from this motor current value exceeds a predetermined increase threshold value, it is determined that a wheel rut WT exists. This increase threshold value is set by experiment or simulation to a value such as 3A. This value is not limited to this.

In addition, when the vehicle V is traveling on a curved road (when the steering wheel 11 is rotated at a predetermined steering angle), an assist force is generated by the electric assist motor 21, and a corresponding motor current value (hereinafter referred to as the reference motor current value) is generated. Therefore, when the increase from this reference motor current value exceeds a predetermined increase threshold, it is determined that a rut WT exists. In this case, information that the vehicle V is traveling on a curved road is required (it is necessary to determine that the steering wheel 11 is rotated at a predetermined steering angle not to obtain a steering force but because the vehicle is traveling on a curved road). Therefore, in this embodiment, the curvature information of the road on which the vehicle V is currently traveling is obtained from the map information stored in the navigation system mounted on the vehicle V. In addition, since the reference motor current value is determined according to the tire steering angle as shown by the thin line in FIG. 2, when it is determined that the road on which the vehicle V is traveling is a curved road based on the map information, the reference motor current value is obtained from the steering angle signal currently transmitted from the steering angle sensor 24. Then, when the motor current value detected by the current sensor 34 exceeds a predetermined increase threshold value with respect to this reference motor current value, it is determined that a wheel rut WT exists.

In addition, when the motor current value is changed according to the vehicle speed when the vehicle V is traveling on a curved road (for example, the motor current value is set higher as the vehicle speed is lower), the reference motor current value is corrected accordingly. The relationship between the vehicle speed and the correction amount of the reference motor current value is set by experiment or simulation. In this case, it is determined that a rut WT exists when the motor current value detected by the current sensor 34 exceeds a predetermined increase threshold value for the corrected reference motor current value. In this case, the vehicle speed information is calculated based on the rotation speed signals of the wheels T1, T2 from the wheel speed sensor 25. In addition, the vehicle speed when traveling on the road may be provisionally set from the speed regulation information (information on the vehicle speed limit) included in the map information stored in the navigation system mounted on the vehicle V, and the reference motor current value may be corrected according to the provisionally set vehicle speed.

The driving information transmission unit 20A receives the determination information (this is the road surface deterioration determination information as referred to in the present invention, which is information on the presence or absence of ruts WT and the size of the ruts WT) from the rut determination unit 29 and the vehicle's position information (position information when the rut determination unit 29 determines that a rut WT exists: the vehicle's position information measured by the GPS module 27), and transmits (sends) the driving information that associates these pieces of information to the data center DS via the communication network CN.

(Data Center)
The data center DS performs information processing according to the driving information (driving information that associates road surface deterioration judgment information with information on the position of the vehicle) received from each driving information transmission unit 20A of each vehicle V, V, ..., and includes as its functional units an information receiving unit 41, a deterioration index creating unit 42, a road surface deterioration estimation information creating unit 43, and a road surface deterioration estimation information providing unit 44. The functions of each of these units are realized by a program stored in a computer provided in the data center DS. An outline of the functions of each of these units will be described below.

The information receiving unit 41 receives the driving information transmitted by the driving information transmitting unit 20A of each vehicle V, V, ....

The deterioration index creation unit 42 creates a deterioration index of the road surface condition for each position on the road surface based on the multiple pieces of driving information received by the information receiving unit 41. In this embodiment, a bar graph (a bar graph with a height corresponding to the degree of deterioration of the road surface) that is overlaid on the map is used as an example of a deterioration index to be displayed on the display screen of the administrator terminal device ATE, and this deterioration index creation unit 42 creates a bar graph corresponding to the degree of deterioration of the road surface. The operation of creating this bar graph will be described below.

Each of the multiple pieces of driving information includes road surface position information and road surface deterioration judgment information at that position (information on the presence or absence of ruts WT and the size of the ruts WT). The deterioration index creation unit 42 collects the road surface deterioration judgment information at the same road surface position and calculates the average value of the deterioration degree of the road surface at that position. For example, the average value of the increase in the motor current value detected by the current sensor 34 relative to the reference motor current value is calculated, and the value is associated with the position of the road surface. This operation is performed for each position (road surface position). As a result, the deterioration index creation unit 42 creates information on the deterioration degree of the road surface at each road surface position as a deterioration index. The size of this deterioration index (the deterioration index that increases as the degree of deterioration of the road surface increases) is specified as the height dimension of the bar graph. The deterioration index information associated with these road surface positions (information on the height dimension of the bar graph) is transmitted to the road surface deterioration estimation information creation unit 43.

The road surface deterioration estimation information creation unit 43 creates road surface deterioration estimation information that associates the deterioration index information received from the deterioration index creation unit 42 with the position information of the road surface that corresponds to that information. In other words, each road surface position on the map is associated with the deterioration index (bar graph) that corresponds to that road surface position, and image information in which the bar graph is overlaid on the map is created as road surface deterioration estimation information. This road surface deterioration estimation information is transmitted to the road surface deterioration estimation information provision unit 44.

The road surface deterioration estimation information providing unit 44 transmits the road surface deterioration estimation information (image information) received from the road surface deterioration estimation information creating unit 43 to the administrator terminal device ATE via the communication network CN or a communication line.

(Administrator terminal device)
The administrator terminal device ATE provides the road surface deterioration estimation information sent from the road surface deterioration estimation information providing unit 44 of the data center DS to the road administrator, and includes as its functional units an information receiving unit 51 and an information display unit 52. The functions of each of these units are realized by a program stored in a computer provided in the administrator terminal device ATE. An outline of the functions of each of these units will be explained below.

The information receiving unit 51 receives road surface deterioration estimation information transmitted from the road surface deterioration estimation information providing unit 44 of the data center DS.

The information display unit 52 displays the road surface deterioration estimation information (image information) received by the information receiving unit 51 on a display screen for providing to a road manager (not shown). This road surface deterioration estimation information is image information in which the bar graph is superimposed on a map.

The map display state displayed on the display screen by this information display unit 52 can be switched between a first map display state in which a wide area (wide-angle area) is displayed, and a second map display state in which a narrow area (narrow-angle area) is displayed.

Figure 16 is a diagram showing an example of a first map display state, and Figure 17 is a diagram showing an example of a second map display state. These map display states can be switched by the operation of the road administrator (operation of the administrator terminal device ATE), and when switching to the second map display state, the area to be enlarged in the first map display state (area circled in Figure 16) can be specified (specified by a pointing device or the like) to switch to the second map display state of the specified area.

In the second map display state, an image of the bar graph superimposed on the map is displayed, and at the position on the road surface where it is determined that a rut WT exists, the size of the rut WT is displayed as the height of the bar graph.

By visually checking the position and height of each bar graph in this second map display state, the road administrator can recognize the size of the wheel ruts WT at each road surface location and determine whether or not the road needs repair. For example, it will be determined that repair is necessary for a road surface location where the height of the bar graph is equal to or greater than a predetermined length.

- Operation of the road surface condition information system -
Next, the operation of the road surface condition information providing system 1 will be described. Fig. 18 is a sequence diagram showing an example of the operation of each of the vehicle V, the data center DS, and the administrator terminal device ATE. In Fig. 18, from the left, the information processing operation in the vehicle V (the operation of determining the rut WT, the operation of creating and transmitting the driving information), the information processing operation in the data center DS (the operation of creating the deterioration index, the operation of creating and providing the road surface deterioration estimation information), and the operation in the administrator terminal device ATE (the operation of displaying the road surface deterioration estimation information) are shown. Note that Fig. 18 shows an example of communication between one vehicle V and the data center DS and the administrator terminal device ATE, but communication between other vehicles V, V, ... and the data center DS and the administrator terminal device ATE is also performed in the same way.

First, in the electric power steering device EPS mounted on the vehicle V, the motor current value is detected by the current sensor 34, and the vehicle's position is measured (obtained) by the GPS module 27 (S1). Then, if the motor current value exceeds a predetermined threshold (the increase from the reference motor current value exceeds a predetermined increase threshold), it is determined that a rut WT exists (a rut existence determination is performed: S2).

When a rut presence determination is made, travel information associating the determination information (information that a rut WT exists and information on the size of the rut WT) with information on the vehicle's position is transmitted to the data center DS. Upon receiving the travel information from each vehicle V, V, ..., the data center DS compiles this travel information (S3) and creates a deterioration index of the road surface condition for each road surface position (S4). Then, road surface deterioration estimation information is created that associates this deterioration index information with the road surface position information corresponding to that information (S5), and this road surface deterioration estimation information is transmitted to the administrator terminal device ATE.

In the administrator terminal device ATE, by receiving this road surface deterioration estimation information, this road surface deterioration estimation information (image information) is displayed on the display screen (S6). In other words, by switching from the first map display state described above to the second map display state, an image is displayed on the map in which a bar graph corresponding to the degree of road surface deterioration (size of the wheel ruts WT) is superimposed.

--Effects of the embodiment--
As described above, in this embodiment, a deterioration index of the road surface condition is created for each position of the road surface based on the travel information collected from a plurality of general vehicles V, V, ..., and road surface deterioration estimation information is provided that associates the deterioration index information with the position information of the road surface corresponding to the information. Therefore, compared to a method in which a dedicated patrol car patrols to detect the road surface condition, it is possible to provide information on road surface deterioration earlier, and as a result, delays in obtaining information on an abnormality occurring on the road surface are suppressed, and delays in the timing of road repairs can be avoided.

In addition, in this embodiment, the deterioration state of the road surface is detected based on the driving information from multiple general vehicles V, V, ..., so there is no need for expensive dedicated patrol cars, and the road surface condition can be detected inexpensively and with high accuracy, and highly reliable road surface deterioration estimation information can be provided.

In addition, in this embodiment, the rut determination unit 29 is configured to transmit driving information when it determines that a rut WT exists because the motor current value exceeds a predetermined threshold. In other words, when the motor current value exceeds a predetermined threshold due to deterioration of the road surface, the driving information is transmitted to the data center DS. This makes it possible to narrow down the information (driving information) transmitted to the data center DS to only useful information, thereby making it possible to use information more efficiently and reducing the load on the data center DS.

(System Variations)
Next, a modified example of the road surface condition information providing system 1 will be described. In the above-mentioned embodiment, the road manager judges whether or not the road needs to be repaired by visually checking the position and height of each bar graph in the second map display state. Instead, in this modified example, the necessity of road repair is judged by machine learning in the data center DS. Since the configuration and operation other than that related to the judgment of the necessity of road repair are the same as those of the above-mentioned embodiment, only the configuration and operation related to the judgment of the necessity of repair will be described here.

Figure 19 is a diagram showing the schematic configuration of the road surface condition information provision system 1 according to this modified example. As shown in this Figure 19, the data center DS of the road surface condition information provision system 1 according to this modified example has, as its functional parts, a road repair determination part 45 in addition to the above-mentioned information receiving part 41, deterioration index creation part 42, road surface deterioration estimation information creation part 43, and road surface deterioration estimation information provision part 44.

The road repair determination unit 45 receives road surface deterioration estimation information from the road surface deterioration estimation information providing unit 44, and determines whether or not the road needs to be repaired by machine learning by comparing this road surface deterioration estimation information with pre-stored teacher information of road surface deterioration estimation information. In other words, road surface deterioration estimation information for which it is determined that there is a need for road repair is stored as information corresponding to each road surface position, and this information is used as teacher information to determine whether or not the road surface deterioration estimation information provided by the road surface deterioration estimation information providing unit 44 indicates that there is a need for road repair. In this case, it is preferable that the teacher information (teacher information for road surface deterioration estimation information) is provided as information that takes into account road environment information such as road bends, speed restrictions, the presence of traffic lights, the presence of temporary stop positions, etc.

If it is determined that the road needs repair, the information (information indicating that the road needs repair) is transmitted to the administrator terminal device ATE as determination information that associates the road surface position information.

In the administrator terminal device ATE, the information receiving unit 51 receives this determination information, and the information display unit 52 displays the location of the road surface that has been determined to require repair on the display screen of the administrator terminal device ATE. For example, the location of the road surface that has been determined to require repair is indicated by flashing the location on the map on the display screen. The road administrator can recognize the presence of a road surface that requires repair by visually checking the display on the display screen.

According to this modified example, the necessity for road repairs can be determined automatically, reducing the burden on road administrators and preventing the road surface from being left in a deteriorated state (in need of repairs) for a long period of time due to an incorrect judgment by the road administrator.

(Parameter Variations)
Next, modified examples of parameters (parameters that change due to changes in the contact state between the steered wheels and the road surface) will be described. In the above-described embodiment and modified examples of the road surface condition information providing system 1, the presence or absence of ruts WT is determined using the motor current value of the electric assist motor 21 as a parameter. Instead, the following parameters can be used.

First, as a parameter, the steering force as a torsional force measured by the steering force sensor 23 can be applied.

As in the above-mentioned embodiment, when the driver applies a steering force to the steering wheel 11 against the forced steering force caused by the rut WT, the steering force increases as the rut WT becomes deeper. Therefore, by measuring this steering force (steering force) with the steering force sensor 23, driving information according to the depth of the rut WT can be obtained, and a deterioration index of the road surface condition can be obtained with high accuracy. In this case, it is necessary to determine that the steering wheel 11 is rotated at a predetermined steering angle (steering force is input) not for driving on a curved road, but for obtaining a steering force. Therefore, as in the above-mentioned embodiment, it is necessary to obtain information that the road on which the vehicle V is currently traveling is a substantially straight road from the map information stored in the navigation system mounted on the vehicle V. In other words, based on the map information, it is determined that a rut WT of a predetermined depth or more exists when the steering force measured by the steering force sensor 23 exceeds a predetermined threshold value, provided that the road on which the vehicle V is currently traveling is a substantially straight road.

In addition, the rotation angle of the electric assist motor 21 measured by the motor rotation angle sensor 22 can be used as a parameter.

When the tires T1, T2 are forcibly steered due to the influence of the ruts WT, the rotor of the electric assist motor 21 is also forcibly rotated. The deeper the ruts WT, the greater the rotation angle of the electric assist motor 21 (the rotation angle at which it is forcibly rotated). In other words, there is a correlation between the depth of the ruts WT and the rotation angle of the electric assist motor 21. For this reason, by setting the parameter as the rotation angle of the electric assist motor 21 and measuring this rotation angle with the motor rotation angle sensor 22, it is possible to obtain driving information according to the depth of the ruts WT.

In addition, the rotation angle of the steering wheel 11 measured by the steering angle sensor (rotation angle sensor) 24 can be used as a parameter.

When the tires are forcibly steered due to the influence of the ruts WT, the steering wheel 11, which is connected via the rack-and-pinion mechanism 13, steering shaft 12, etc., is also forcibly turned. The deeper the ruts WT, the greater the rotation angle of the steering wheel 11 (the angle at which the steering wheel 11 is forcibly turned). In other words, there is a correlation between the depth of the ruts WT and the rotation angle of the steering wheel 11. For this reason, by setting the parameter as the rotation angle of the steering wheel 11 and measuring the rotation angle of the steering wheel 11 with the steering angle sensor 24, it is possible to obtain driving information according to the depth of the ruts WT.

In addition, the difference between the rotational speeds of the left and right tires T1, T2 measured by the wheel speed sensor 25 can be used as a parameter.

When only one of the left and right tires T1, T2 enters the rut WT, the height position of this one tire becomes lower than the height position of the other tire, resulting in a situation where the tire is forcibly steered towards this one tire. In this case, the rotational speed of one tire becomes lower than the rotational speed of the other tire. The deeper the rut WT, the greater the difference in rotational speed. In other words, there is a correlation between the depth of the rut WT and the difference in the rotational speed of each of the left and right tires T1, T2. For this reason, the parameter is set to the difference in the rotational speed of each of the left and right tires T1, T2, and by measuring the rotational speed of each of the left and right tires T1, T2 using the wheel speed sensor 25, it is possible to obtain driving information according to the depth of the rut WT.

In addition, the vertical acceleration and horizontal acceleration of the vehicle V measured by the G sensor 26 can be used as the parameters.

When only one of the left and right tires T1, T2 gets into the rut WT, vertical and lateral acceleration occurs in the vehicle V. Also, when both left and right tires T1, T2 get into the rut WT at approximately the same time, vertical acceleration occurs in the vehicle V. These accelerations become larger as the depth of the rut WT increases. Therefore, by setting the parameters as the vertical and lateral accelerations of the vehicle V and measuring these accelerations using the G sensor 26, it is possible to obtain driving information according to the depth of the rut WT.

In addition, in a vehicle V in which the left and right tires T1, T2 can be steered independently, the difference in the steering angle between the left and right tires T1, T2 can be applied as the parameter.

When one tire is forcibly steered due to the influence of the rut WT, the steering angle of that tire increases, resulting in a difference in the steering angles of the left and right tires T1, T2, and this difference increases as the depth of the rut WT increases. In other words, there is a correlation between the depth of the rut WT and the difference in the steering angles of the tires T1, T2. For this reason, by setting the parameter as the difference in the steering angles of the tires T1, T2 and measuring the difference in steering angles using a steering angle sensor (not shown), it is possible to obtain driving information according to the depth of the rut WT.

As parameters that change due to changes in the contact state between the steering wheel and the road surface, the motor current value in the above-mentioned embodiment and the parameters listed in this modified example (steering force, rotation angle of the electric assist motor 21, rotation angle of the steering wheel 11, difference in rotation speed between the left and right tires T1, T2, acceleration of the vehicle V, difference in steering angle between the left and right tires T1, T2) may be combined to perform the rut WT determination operation. For example, if it is determined that a rut WT exists in the rut WT determination operation using each of the multiple parameters, the driving information may be transmitted to the data center DS.

-Other embodiments-
The present invention is not limited to the above-described embodiment and each of the modifications, and all modifications and applications encompassed within the scope of the claims and equivalents thereto are possible.

For example, in the above embodiment and each of the above modified examples, a case has been described in which a rack-assist type electric power steering device EPS is used to construct the road surface condition information providing system 1 according to the present invention. The present invention is not limited to this, and the road surface condition information providing system 1 according to the present invention may be constructed using other types of electric power steering devices (column assist type, pinion assist type, etc.). It is also possible to apply a steer-by-wire type steering system.

In addition, in the above embodiment and each of the above modified examples, a rut determination unit 29 is provided as a functional unit of the steering ECU 20 mounted on the vehicle V, and the rut determination unit 29 determines whether or not a rut WT is present, and then transmits driving information to the data center DS. The present invention is not limited to this, and the driving information transmission unit 20A of the steering ECU 20 may transmit driving information that associates the motor current value with information on the position of the vehicle from which the motor current value was obtained to the data center DS, and the data center DS may determine whether or not a rut WT is present from the multiple pieces of driving information received and create a deterioration index.

In addition, in the above embodiment and each of the above modified examples, it is determined that a rut WT exists when the parameter value exceeds a predetermined threshold (in the above embodiment, when the increase from the reference motor current value exceeds a predetermined increase threshold). The present invention is not limited to this, and it may be determined that a rut WT exists when the change in the parameter value per unit time exceeds a predetermined threshold (in the above embodiment, when the change in the motor current value per unit time exceeds a predetermined threshold). In this case, when the contact state between the tires (steered wheels) T1, T2 and the road surface changes significantly, the driving information is transmitted from the driving information transmission unit 20A to the data center DS when the change in the parameter value per unit time exceeds a predetermined threshold. Therefore, in this case, it is possible to increase the efficiency of information use and reduce the load on the data center DS. For example, in the case of the change in motor current value shown in FIG. 15 described above, if the amount of change per unit time in the motor current value during the period from timing t1 to timing t2 in the figure (the gradient of change in the motor current value) exceeds a predetermined threshold value, it is determined that a rut WT exists, and driving information is transmitted from the driving information transmission unit 20A to the data center DS.

In the above embodiment and each of the above modified examples, the height dimension of the bar graph, which is the deterioration index, is set by tallying up the road surface deterioration judgment information at the same road surface position and calculating the average value of the deterioration degree of the road surface at that road surface position. The present invention is not limited to this, and the parameters (motor current value, etc.) may be received from each vehicle V, V, ..., and the average value of the peak value of the parameter at the same road surface position (for example, the peak value of the motor current value) divided by the tire steering angle at that road surface position may be calculated as the deterioration index. The deterioration index may also be set by calculating the moving average value or weighted moving average value of the deterioration degree of the road surface. Furthermore, the deterioration index is not limited to a bar graph. For example, the deterioration index may be displayed numerically on a map, or the time when the road will need repairs may be predicted and the time may be displayed numerically on a map.

In addition, as a form of use of the road surface condition information providing system 1 according to the present invention, the deterioration index created by the data center DS may be associated with information on the date the deterioration index was created and stored, and the change over time in the deterioration index, i.e., the change over time in the deterioration state of the road surface, may be compiled. This makes it easy to grasp the progress of road surface deterioration, making it possible to estimate the time when road repairs will be required and is effective in allowing preparations for road repairs to be made in advance.

As another use form of the road surface condition information providing system 1 according to the present invention, the number of vehicles V that have been determined to have ruts WT by the rut determination unit 29 among a plurality of vehicles V, V, ... that have passed a specific road surface may be grasped. In other words, by grasping the ratio of the number of vehicles V that have been determined to have ruts WT using a camera or the like installed on the road, it becomes possible to judge the reliability of the driving information transmitted to the data center DS. In this case, when the ratio of the number of vehicles V that have been determined to have ruts WT is high (for example, 50% or more: when the reliability of the driving information is high), the deterioration index is created in the deterioration index creation unit 42, while when the ratio of the number of vehicles V that have been determined to have ruts WT is low (for example, less than 50%: when the reliability of the driving information is low), the deterioration index creation unit 42 does not create a deterioration index. These numerical values are not limited to these.

The present invention can also be applied as a road surface condition information system 1 including an autonomous vehicle. In other words, the road surface condition information system 1 includes a vehicle equipped with an electric power steering device that automatically applies a steering force due to the presence of a wheel rut WT.

In addition, road surface deterioration is not limited to ruts, but can also be applied when bumps occur on the road surface.

The present invention can be applied to a road surface condition information providing system that provides information on road surface deterioration at an early stage.

1 Road surface condition information providing system 11 Steering wheel 20 Steering ECU
20A: Travel information transmission unit 21: Electric assist motor 22: Motor rotation angle sensor (measurement means)
23 Steering force sensor (measurement means)
24 Steering angle sensor (rotation angle sensor, measuring means)
25 Wheel speed sensor (measuring means)
26 G sensor (acceleration sensor, measuring means)
27 GPS module (position detection means)
34 Current sensor (measuring means)
41 Information receiving unit 42 Deterioration index creating unit 43 Road surface deterioration estimation information creating unit 44 Road surface deterioration estimation information providing unit 45 Road repair judgment unit DS Data center (information collection device)
ATE Administrator terminal device V Vehicle (general vehicle)
T1 Left front wheel, left tire (steered wheel)
T2 Right front wheel, right tire (steered wheel)
EPS Electric Power Steering Unit WT Wadachi

Claims (7)

A road surface condition information providing system that provides information on the deterioration state of a road surface,
The system includes a plurality of general vehicles and an information collection device capable of communicating with the plurality of general vehicles,
Each of the general vehicles includes a position detection means for detecting a vehicle position, a measurement means for measuring a value of a parameter that changes due to a change in a contact state between a steering wheel and the road surface, and a driving information transmission unit for transmitting driving information that associates information on the vehicle position detected by the position detection means with information on the value of the parameter measured by the measurement means at the vehicle position or road surface deterioration determination information based on the value of the parameter,
the information collecting device includes an information receiving unit that receives the traveling information transmitted from the traveling information transmitting unit of each of the general vehicles, a deterioration index creating unit that creates a deterioration index of a road surface condition for each position of the road surface based on the plurality of pieces of traveling information received by the information receiving unit, a road surface deterioration estimation information creating unit that creates road surface deterioration estimation information that associates information on the deterioration index created by the deterioration index creating unit with position information of the road surface corresponding to the information, and a road surface deterioration estimation information providing unit that provides the road surface deterioration estimation information ,
The parameter that changes due to a change in the contact state between the steering wheel and the road surface is a current value of an electric assist motor provided in an electric power steering device,
The road surface condition information providing system according to the present invention, wherein the measuring means is a current sensor that measures the current value . A road surface condition information providing system that provides information on the deterioration state of a road surface,
The system includes a plurality of general vehicles and an information collection device capable of communicating with the plurality of general vehicles,
Each of the general vehicles includes a position detection means for detecting a vehicle position, a measurement means for measuring a value of a parameter that changes due to a change in a contact state between a steering wheel and the road surface, and a driving information transmission unit for transmitting driving information that associates information on the vehicle position detected by the position detection means with information on the value of the parameter measured by the measurement means at the vehicle position or road surface deterioration determination information based on the value of the parameter,
the information collecting device includes an information receiving unit that receives the traveling information transmitted from the traveling information transmitting unit of each of the general vehicles, a deterioration index creating unit that creates a deterioration index of a road surface condition for each position of the road surface based on the plurality of pieces of traveling information received by the information receiving unit, a road surface deterioration estimation information creating unit that creates road surface deterioration estimation information that associates information on the deterioration index created by the deterioration index creating unit with position information of the road surface corresponding to the information, and a road surface deterioration estimation information providing unit that provides the road surface deterioration estimation information,
The parameter that changes due to a change in the contact state between the steering wheel and the road surface is a rotation angle of an electric assist motor provided in an electric power steering device,
The road surface condition information providing system according to the present invention, wherein the measuring means is a motor rotation angle sensor that measures the rotation angle. A road surface condition information providing system that provides information on the deterioration state of a road surface,
The system includes a plurality of general vehicles and an information collection device capable of communicating with the plurality of general vehicles,
Each of the general vehicles includes a position detection means for detecting a vehicle position, a measurement means for measuring a value of a parameter that changes due to a change in a contact state between a steering wheel and the road surface, and a driving information transmission unit for transmitting driving information that associates information on the vehicle position detected by the position detection means with information on the value of the parameter measured by the measurement means at the vehicle position or road surface deterioration determination information based on the value of the parameter,
the information collecting device includes an information receiving unit that receives the traveling information transmitted from the traveling information transmitting unit of each of the general vehicles, a deterioration index creating unit that creates a deterioration index of a road surface condition for each position of the road surface based on the plurality of pieces of traveling information received by the information receiving unit, a road surface deterioration estimation information creating unit that creates road surface deterioration estimation information that associates information on the deterioration index created by the deterioration index creating unit with position information of the road surface corresponding to the information, and a road surface deterioration estimation information providing unit that provides the road surface deterioration estimation information,
The parameter that changes due to a change in the contact state between the steered wheels and the road surface is a difference in steering angle between the left and right steered wheels when the left and right steered wheels are independently steerable,
A road surface condition information providing system, wherein the measuring means is a steering angle sensor that measures the steering angle of each of the left and right steered wheels. 4. The road surface condition information providing system according to claim 1, 2 or 3,
A road surface condition information providing system characterized in that, when the value of the parameter exceeds a predetermined threshold, driving information that associates the information on the vehicle position from which the value of the parameter was obtained with road surface deterioration judgment information based on the value of the parameter is transmitted from a driving information transmitting unit. 4. The road surface condition information providing system according to claim 1, 2 or 3,
A road surface condition information providing system characterized in that, when the amount of change per unit time of the value of the parameter exceeds a predetermined threshold, driving information associating information on the vehicle position where the amount of change exceeds the predetermined threshold with road surface deterioration judgment information based on the amount of change is transmitted from a driving information transmitting unit. 4. The road surface condition information providing system according to claim 1, 2 or 3,
A road surface condition information providing system, wherein the road surface deterioration estimation information providing unit transmits the road surface deterioration estimation information to a terminal device monitored by a road administrator. 4. The road surface condition information providing system according to claim 1, 2 or 3,
A road surface condition information providing system characterized in that the road surface deterioration estimation information providing unit transmits the road surface deterioration estimation information to a road repair judgment unit that determines whether or not road repair is necessary through machine learning by comparing the provided road surface deterioration estimation information with pre-stored teacher information for the road surface deterioration estimation information.

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