JP2022086894A - Arithmetic unit and program - Google Patents

Abstract

To appropriately confirm the condition of a road surface of a road even if a detection condition of a vehicle side is different.SOLUTION: An arithmetic unit includes a vehicle behavior information acquisition part for acquiring vehicle behavior information showing a vehicle behavior detected by a plurality of sensors provided at different positions of a vehicle 10 traveling on a road, and a road surface condition information acquisition part for acquiring road surface condition information showing a road surface condition of the road by estimating a transfer function showing a relation between the road surface condition of the road as an input and the vehicle behavior information as an output on the basis of a plurality of pieces of vehicle behavior information.SELECTED DRAWING: Figure 5

Description

The present invention relates to arithmetic units and programs.

For example, as shown in Patent Document 1, there is known a technique of detecting the vibration of a vehicle traveling on a road and diagnosing the uneven state of the road surface based on the vibration data.

Japanese Unexamined Patent Publication No. 2014-108988

However, even if the vehicle is traveling on the same road, if the detection conditions on the vehicle side are different, for example, the vehicle type is different, the behavior of the vehicle will be different, and the condition of the road surface may not be detected properly. be. Therefore, even if the detection conditions on the vehicle side are different, it is required to appropriately detect the condition of the road surface.

The present invention has been made in view of the above, and an object of the present invention is to provide an arithmetic unit and a program capable of appropriately detecting the state of the road surface of a road even when the detection conditions on the vehicle side are different. do.

In order to solve the above-mentioned problems and achieve the object, the arithmetic unit according to the present disclosure has vehicle behavior information indicating the behavior of the vehicle detected by a plurality of sensors provided at different positions of the vehicle traveling on the road. By estimating the transmission function indicating the relationship between the road surface state of the road as an input and the vehicle behavior information as an output, based on the vehicle behavior information acquisition unit for acquiring A road surface condition information acquisition unit for acquiring road surface condition information indicating the road surface condition of the road is included.

In order to solve the above-mentioned problems and achieve the object, the program according to the present disclosure uses vehicle behavior information indicating the behavior of the vehicle detected by a plurality of sensors provided at different positions of the vehicle traveling on the road. Based on the acquired step and the plurality of vehicle behavior information, the road surface condition of the road is estimated by estimating the transmission function indicating the relationship between the road surface condition of the road as an input and the vehicle behavior information as an output. The computer is made to execute a calculation method including a step of acquiring road surface condition information indicating the above.

According to the present invention, even when the detection conditions on the vehicle side are different, the state of the road surface can be appropriately confirmed.

FIG. 1 is a schematic block diagram of the detection system according to the present embodiment. FIG. 2 is a schematic view of the vehicle. FIG. 3 is a schematic diagram of the vehicle. FIG. 4 is a schematic block diagram of the arithmetic unit. FIG. 5 is a schematic diagram illustrating the calculation of the road surface condition. FIG. 6 is a flowchart illustrating a calculation flow of the road surface condition according to the present embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below.

(Detection system)
FIG. 1 is a schematic block diagram of the detection system according to the present embodiment. As shown in FIG. 1, the detection system 1 according to the present embodiment includes a vehicle 10, a measurement data acquisition device 12, and an arithmetic unit 14. The detection system 1 is a system for determining the road surface condition of the road R based on the vehicle behavior information of the vehicle 10 traveling on the road R. The vehicle behavior information is information indicating the behavior of the vehicle 10 traveling on the road R, and will be described in detail later. The detection system 1 determines the road surface condition of the road R by calculating the road surface condition of the road R based on the vehicle behavior information by the arithmetic unit 14. The road surface condition is an index indicating the degree of unevenness of the road surface in the present embodiment. Furthermore, in the present embodiment, the road surface condition is information indicating the height of the road surface in the vertical direction. For example, the road surface condition at a certain position on the road R is in the traveling direction of the vehicle 10 rather than the position. It may be the difference in the height of the road surface at that position with respect to the height of the road surface in front of a unit distance along the road. Further, for example, the road surface condition may be at least one of IRI (International Roughness Index), road surface flatness, cracking, rutting, and MCI (Maintenance Control Index). Further, for example, the road surface condition may be information indicating the presence or absence of an object on the road R that affects the degree of unevenness of the road surface, such as the presence or absence of a manhole or the presence or absence of a seam of a bridge, and affects the degree of unevenness of the road surface. It may include information indicating the presence or absence of an object to be exerted and the above-mentioned information (IRI, etc.). Further, the road surface condition information is not limited to the index indicating the degree of unevenness of the road surface as long as it is an index indicating the condition of the road surface.

In the detection system 1, the vehicle 10 detects the vehicle behavior information while traveling on the road R, and transmits the detected vehicle behavior information to the measurement data acquisition device 12. The measurement data acquisition device 12 is, for example, a device (computer) managed by an entity that manages the road R. The measurement data acquisition device 12 transmits the vehicle behavior information transmitted from the vehicle 10 to the arithmetic unit 14. The arithmetic unit 14 calculates the road surface condition of the road R on which the vehicle 10 has traveled, based on the vehicle behavior information transmitted from the measurement data acquisition device 12. Then, the arithmetic unit 14 transmits the calculation result of the road surface condition to the measurement data acquisition device 12. As described above, the arithmetic unit 14 acquires vehicle behavior information via the measurement data acquisition device 12, but is not limited thereto. For example, the detection system 1 is not provided with the measurement data acquisition device 12, and the arithmetic unit 14 may acquire vehicle behavior information directly from the vehicle 10.

(vehicle)
2 and 3 are schematic views of the vehicle. The Z direction in FIGS. 2 and 3 points upward in the vertical direction, FIG. 2 is a schematic view when the vehicle 10 is viewed from above in the vertical direction, and FIG. 3 is a schematic view when the vehicle 10 is viewed from the side. It is a schematic diagram. As shown in FIG. 2, the vehicle 10 includes a position sensor 10A, a plurality of behavior sensors 10B, and a measuring device 10C. The position sensor 10A is a sensor that acquires the position information of the vehicle 10. The position information of the vehicle 10 is information indicating the earth coordinates of the vehicle 10. The position sensor 10A is a module for GNSS (Global Navigation Satellite System) in this embodiment.

The behavior sensor 10B is a sensor that detects vehicle behavior information indicating the behavior of the vehicle 10. The vehicle behavior information may be any information as long as it is information indicating the behavior of the vehicle 10 traveling on the road. Each behavior sensor 10B may detect different types of vehicle behavior information, but it is preferable to detect the same type of vehicle behavior information. In the present embodiment, the behavior sensor 10B preferably detects the acceleration of the vehicle 10 as vehicle behavior information. In this case, the behavior sensor 10B is an acceleration sensor that detects acceleration, and more preferably an acceleration sensor that detects acceleration in three axes. Further, the vehicle behavior information detected by the behavior sensor 10B is not limited to acceleration, for example, acceleration, image data obtained by capturing the surroundings of the vehicle 10, speed of the vehicle 10, angular velocity of the vehicle 10, and steering angle of the vehicle 10. , The brake amount of the vehicle 10, the operation of the wiper of the vehicle 10, and the operation amount of the suspension of the vehicle 10 may be at least one. Since the image data around the vehicle 10 changes depending on the movement of the vehicle 10, it can be said that it is information indicating the behavior of the vehicle 10. The behavior sensor 10B for detecting the captured image around the vehicle 10 is, for example, a camera, the behavior sensor 10B for detecting the speed of the vehicle 10 is, for example, a speed sensor, and the behavior sensor 10B for detecting the speed of the vehicle 10 is, for example, three axes. The behavior sensor 10B, which is a gyro sensor and detects the steering angle of the vehicle 10, is, for example, a steering sensor, and the behavior sensor 10B, which detects the brake amount of the vehicle 10, is, for example, a brake sensor, and detects the operation of the wiper of the vehicle 10. Examples of the behavior sensor 10B include a wiper sensor, and examples of the behavior sensor 10B for detecting the operating amount of the suspension of the vehicle 10 include a suspension sensor.

The respective behavior sensors 10B are mounted at different positions in the vehicle 10. As shown in FIG. 3, the behavior sensor 10B is provided on the Z direction side of the suspension SU provided on the tire (wheel) TR of the vehicle 10. That is, the behavior sensor 10B is provided on the side opposite to the tire TR (Z direction side) with respect to the suspension SU of the vehicle 10. In the example of FIG. 2, as the behavior sensor 10B, the behavior sensor 10B1 provided on the Z direction side of the suspension SU of the tire TR1 which is the front wheel on the left side and the behavior sensor 10B1 provided on the Z direction side of the suspension SU of the tire TR2 which is the front wheel on the right side are provided. The behavior sensor 10B2, the behavior sensor 10B3 provided on the Z direction side of the suspension SU of the tire TR3 which is the left rear wheel, and the behavior sensor 10B4 provided on the Z direction side of the suspension SU of the tire TR4 which is the right rear wheel. including. However, the position where the behavior sensor 10B is provided is arbitrary, and is not limited to, for example, being provided on the Z direction side of the suspension SU. Further, the number of the behavior sensors 10B is not limited to four, but may be arbitrary, and may be any number of two or more. Further, in the example of FIG. 2, the number of tire TRs is four, but the number is arbitrary, and may be, for example, two or more arbitrary numbers.

The arithmetic unit 14 of the present embodiment acquires vehicle behavior information detected by each of these behavior sensors 10B (behavior sensors 10B1 to 10B4 in the example of FIG. 2), and calculates the road surface state.

In addition to the behavior sensor 10B described above, the vehicle 10 may be provided with a sensor for detecting vehicle behavior information. For example, a sensor for detecting vehicle behavior information may be provided below the suspension SU in the vertical direction. When a sensor for detecting vehicle behavior information is provided in addition to the behavior sensor 10B, the arithmetic unit 14 detects the vehicle behavior information among the vehicle behavior information detected by these plurality of sensors. It can be said that the road surface condition is calculated using the vehicle behavior information.

The measuring device 10C is a device that controls the position sensor 10A and the behavior sensor 10B to detect the position information and the vehicle behavior information of the vehicle 10 and records the detected position information and the vehicle behavior information. That is, the measuring device 10C functions as a data logger that records the position information and the vehicle behavior information of the vehicle 10. The measuring device 10C can be said to be a computer, and includes a control unit 10C1, a storage unit 10C2, and a communication unit 10C3. The control unit 10C1 is an arithmetic unit, that is, a CPU (Central Processing Unit). The storage unit 10C2 is a memory that stores various information such as calculation contents and programs of the control unit 10C1, position information of the vehicle 10, and vehicle behavior information. For example, a RAM (Random Access Memory) and a ROM (Read Only Memory). Such as, and at least one of non-volatile storage devices such as flash memory and HDD (Hard Disk Drive). The program for the control unit 10C1 stored by the storage unit 10C2 may be stored in a recording medium readable by the measuring device 10C. The communication unit 10C3 is a communication module that communicates with an external device, such as an antenna.

The control unit 10C1 reads out the program stored in the storage unit 10C2 and executes the control of the position sensor 10A and the behavior sensor 10B. The control unit 10C1 causes the behavior sensor 10B to detect the vehicle behavior information of the vehicle 10 at predetermined time intervals while the vehicle 10 is traveling on the road. Further, the control unit 10C1 causes the position sensor 10A to detect the position information of the vehicle 10 at the timing when the behavior sensor 10B detects the vehicle behavior information. That is, the control unit 10C1 causes the behavior sensor 10B to detect the vehicle behavior information of the vehicle 10 and causes the position sensor 10A to detect the position information of the vehicle 10 each time the vehicle 10 travels for a predetermined time. The predetermined time here is preferably a fixed time such as 1 minute, but the predetermined time is not limited to a fixed time and may be any length. That is, the predetermined time may change each time. For example, the current detection may be performed at the timing when 1 minute has elapsed from the previous detection, and the next detection may be performed at the timing when 3 minutes have elapsed from the current detection.

Hereinafter, the position information of the vehicle 10 at the timing when the behavior sensor 10B detects the vehicle behavior information is appropriately referred to as vehicle position information. The vehicle position information can also be said to be information (coordinates) of the position where the vehicle behavior information is detected.

The control unit 10C1 acquires the vehicle behavior information of the vehicle 10 detected at predetermined time intervals and the vehicle position information, associates the acquired vehicle behavior information with the vehicle position information, and stores the acquired vehicle behavior information in the storage unit 10C2. That is, the vehicle behavior information and the vehicle position information detected at the same timing are associated with each other. Therefore, the associated vehicle behavior information and vehicle position information are stored in the storage unit 10C2 at each detected timing. The vehicle position information and the vehicle behavior information associated here are detected at the same timing, but are not limited to exactly the same timing, and may be detected at different timings. In this case, for example, the vehicle position information in which the difference in detection timing is equal to or less than a predetermined value and the vehicle behavior information are treated as if they were detected at the same timing and are associated with each other.

The control unit 10C1 transmits the associated vehicle behavior information and vehicle position information to the measurement data acquisition device 12 via the communication unit 10C3. The measurement data acquisition device 12 transmits the vehicle behavior information and the vehicle position information received from the vehicle 10 to the arithmetic unit 14. If the measurement data acquisition device 12 is not provided, the control unit 10C1 may directly transmit the associated vehicle behavior information and vehicle position information to the arithmetic unit 14.

(Relationship between vehicle behavior information and road surface condition)
Here, the road surface condition affects the behavior of the vehicle 10 via the tire TR in contact with the road surface. For example, the tire TR vibrates according to the unevenness of the road surface (road surface condition), and the vibration is transmitted to the entire vehicle 10, so that the acceleration of the vehicle 10 (vehicle behavior information) changes according to the unevenness of the road surface (road surface condition). do. Since the vehicle behavior information changes according to the road surface condition in this way, the road surface condition can be estimated based on the vehicle behavior information. However, when the vehicle is different, the vibration is transmitted differently, so that the detected vehicle behavior information may be different even if the vehicle travels on a road with the same road surface condition. For example, in a lighter vehicle, the vibration may be amplified and the acceleration change may be larger. In addition, the vehicle behavior information may differ depending on the position and type of the sensor that detects the vehicle behavior information.

The relationship between the road surface condition and the vehicle behavior information described above can be rephrased as follows. In the vehicle 10, the road surface condition as an input signal is converted into a signal such as vibration and input to the vehicle 10 via the tire TR. Then, the signal (for example, vibration) is modulated by the vehicle 10 and transmitted to the position where the behavior sensor 10B is provided, and the behavior sensor 10B detects the transmitted signal as an output signal (for example, acceleration). In this case, since the degree of signal modulation differs depending on the detection conditions such as the vehicle type, the sensor position, and the type, when the detection conditions change, the output signal (vehicle behavior information) detected by the behavior sensor 10B also changes. That is, since the transfer function when the road surface condition is used as the input signal and the vehicle behavior information is used as the output signal differs depending on the detection conditions on the vehicle 10 side, it can be said that the vehicle behavior information changes even if the road surface condition is the same. .. The transfer function here can be said to be a function showing the relationship between the road surface state, which is an input signal, and the vehicle behavior information, which is an output signal.

In this way, even if the road surface condition is the same, the transfer function changes according to the detection conditions on the vehicle 10 side, and the vehicle behavior information detected as a result differs. Therefore, the road surface condition is appropriately estimated based on the vehicle behavior information. It may not be possible. Therefore, even if the detection conditions on the vehicle 10 side are different, in other words, it is required to appropriately estimate the road surface condition regardless of the detection conditions on the vehicle 10 side. On the other hand, the arithmetic unit 14 according to the present embodiment can appropriately detect the road surface state regardless of the detection conditions on the vehicle 10 side by estimating the transfer function from the plurality of vehicle behavior information. Hereinafter, the arithmetic unit 14 will be specifically described.

(Arithmetic logic unit)
FIG. 4 is a schematic block diagram of the arithmetic unit. As shown in FIG. 4, the arithmetic unit 14 is, for example, a computer, and includes a communication unit 20, a storage unit 22, and a control unit 24. The communication unit 20 is a communication module that communicates with an external device, such as an antenna. The storage unit 22 is a memory that stores various information such as calculation contents and programs of the control unit 24. For example, a RAM, a main storage device such as a ROM, and a non-volatile storage device such as a flash memory or an HDD. Of these, at least one is included. The program for the control unit 24 stored by the storage unit 22 may be stored in a recording medium readable by the arithmetic unit 14.

The control unit 24 is an arithmetic unit, that is, a CPU. The control unit 24 includes a vehicle behavior information acquisition unit 30 and a road surface condition information acquisition unit 32. The control unit 24 reads the program (software) from the storage unit 22 and executes it to realize the vehicle behavior information acquisition unit 30 and the road surface condition information acquisition unit 32, and executes their processing. The control unit 24 may execute these processes by one CPU, or may include a plurality of CPUs and execute the processes by the plurality of CPUs. Further, at least a part of the vehicle behavior information acquisition unit 30 and the road surface condition information acquisition unit 32 may be realized by hardware.

(Vehicle behavior information acquisition unit)
The vehicle behavior information acquisition unit 30 acquires vehicle behavior information detected by a plurality of behavior sensors 10B. That is, the vehicle behavior information acquisition unit 30 acquires a plurality of vehicle behavior information detected at different positions in the vehicle 10. In the example of the present embodiment, the vehicle behavior information acquisition unit 30 includes vehicle behavior information detected by the behavior sensor 10B1, vehicle behavior information detected by the behavior sensor 10B2, vehicle behavior information detected by the behavior sensor 10B3, and a behavior sensor. The vehicle behavior information detected by 10B4 is acquired. Furthermore, the vehicle behavior information acquisition unit 30 acquires the vehicle position information associated with the vehicle behavior information together with the vehicle behavior information. That is, the vehicle behavior information acquisition unit 32 acquires the vehicle behavior information detected by the plurality of behavior sensors 10B and the vehicle position information when the vehicle behavior information is detected. The vehicle behavior information acquisition unit 30 acquires the vehicle behavior information and the vehicle position information sequentially detected by the vehicle 10.

The vehicle behavior information acquisition unit 30 acquires vehicle behavior information and vehicle position information from the measurement data acquisition device 12 via the communication unit 20. However, when the measurement data acquisition device 12 is not provided, the vehicle behavior information acquisition unit 30 may acquire the vehicle behavior information and the vehicle position information directly from the measurement device 10C of the vehicle 10.

(Road surface condition information acquisition unit)
The road surface condition information acquisition unit 32 estimates a transmission function indicating the relationship between the road surface condition as an input signal and the vehicle behavior information as an output signal, based on a plurality of vehicle behavior information acquired by the vehicle behavior information acquisition unit 30. By doing so, the road surface condition information indicating the road surface condition is acquired. As described above, the transfer function differs depending on the detection condition on the vehicle side, and the transfer function for each detection condition is usually unknown. Therefore, the transfer function for each detection condition is not calculated in advance, and the road surface information is used using the vehicle behavior information. Is difficult to calculate. On the other hand, the road surface condition information acquisition unit 32 can calculate the road surface information by estimating the transfer function based on a plurality of vehicle behavior information without calculating the transfer function for each detection condition in advance. .. Specifically, in the present embodiment, the road surface condition information acquisition unit 32 estimates the transfer function and calculates the road surface condition based on a plurality of vehicle behavior information by using the principle of blind signal source separation. Hereinafter, a specific description will be given.

The road surface condition information acquisition unit 32 assumes that each of the signals (for example, vibration) to the tires TR1 to TR4 according to the road surface condition affects each of the vehicle behavior information, and the transmission function based on the vehicle behavior information. Is estimated, and the road surface condition for each position on the road R with which the tire TR contacts is calculated. That is, the road surface condition information acquisition unit 32 estimates the transfer function and calculates the road surface condition on the assumption that the signal to each tire TR is transmitted to all the behavior sensors 10B. In the example of the present embodiment, in the road surface condition information acquisition unit 32, the signals to the tires TR1, TR2, TR3, TR4 (vibrations of the tires TR1, TR2, TR3, TR4) are the vehicle behavior information detected by the behavior sensor 10B1. , The transmission function is estimated assuming that it affects the vehicle behavior information detected by the behavior sensor 10B2, the vehicle behavior information detected by the behavior sensor 10B3, and the vehicle behavior information detected by the behavior sensor 10B4, and the tire TR1 , TR2, TR3, and TR4 are in contact with each other to calculate the road surface condition. The tires TR1, TR2, TR3, and TR4 come into contact with the road R at different positions. Therefore, the road surface condition information acquisition unit 32 estimates the transfer function and calculates the road surface condition on the assumption that each of the signals corresponding to the road surface conditions input to different positions affects each of the vehicle behavior information. It can be said to do.

Further, the road surface condition information acquisition unit 32 receives each combination of the signal to the tire TR and the vehicle behavior information according to the road surface condition (for each 1: 1 combination of the signal to the tire TR and the vehicle behavior information). The transmission function is estimated to calculate the road surface condition for each position on the road R with which the tire TR contacts. In other words, the road surface condition information acquisition unit 32 is a transfer function for each combination of the road surface condition at each position of the road R and each vehicle behavior information (for each 1: 1 combination of the road surface condition and the vehicle behavior information). Is estimated, and the road surface condition for each position of the road R is calculated. That is, the road surface condition information acquisition unit 32 assumes that the degree of modulation when the signal is transmitted to the behavior sensor 10B differs for each combination of the tire TR and the behavior sensor 10B, and determines that each combination of the tire TR signal and the vehicle behavior information In other words, the transfer function is estimated for each combination of the road surface condition at the position of the road R and the vehicle behavior information. In the example of the present embodiment, the road surface condition information acquisition unit 32 is a combination of the tire TR1 and the behavior sensor 10B1, a combination of the tire TR1 and the behavior sensor 10B2, a combination of the tire TR1 and the behavior sensor 10B3, and a combination of the tire TR1 and the behavior sensor 10B4. , Combination of tire TR2 and behavior sensor 10B1, combination of tire TR2 and behavior sensor 10B2, combination of tire TR2 and behavior sensor 10B3, combination of tire TR2 and behavior sensor 10B4, combination of tire TR3 and behavior sensor 10B1, tire TR3 and behavior Combination of sensor 10B2, combination of tire TR3 and behavior sensor 10B3, combination of tire TR3 and behavior sensor 10B4, combination of tire TR4 and behavior sensor 10B1, combination of tire TR4 and behavior sensor 10B2, combination of tire TR4 and behavior sensor 10B3, A total of 16 transmission functions of the combination of the tire TR4 and the behavior sensor 10B4 are estimated.

More specifically, the road surface condition information acquisition unit 32 assumes that an equation showing the relationship between the vehicle behavior information, the road surface condition for each position, and the transfer function between the road surface condition and the vehicle behavior information is established for each vehicle behavior information. Moreover, assuming that the vehicle behavior information is independent of each other, the transfer function and the road surface state are calculated by solving the simultaneous equations for each vehicle behavior information. Independence of vehicle behavior information means that vehicle behavior information does not affect each other. FIG. 5 is a schematic diagram illustrating the calculation of the road surface condition. As shown in FIG. 5, the vehicle behavior information detected by the behavior sensor 10B1 is X1, the vehicle behavior information detected by the behavior sensor 10B2 is X2, the vehicle behavior information detected by the behavior sensor 10B3 is X3, and the behavior sensor 10B4 The detected vehicle behavior information is X4, the road surface condition at the position on the road R in contact with the tire TR1 is S1, the road surface condition at the position on the road R in contact with the tire TR2 is S2, and the tire TR3 is contacted. The road surface condition at the position on the road R is S3, and the road surface condition at the position on the road R in contact with the tire TR4 is S4. Further, the transmission function with the road surface state S1 as the input signal and the vehicle behavior information X1 as the output signal is A11, the transmission function with the road surface state S1 as the input signal and the vehicle behavior information X2 as the output signal is A12, and the road surface state S1 is set. The transmission function with the input signal and the vehicle behavior information X3 as the output signal is A13, the transmission function with the road surface condition S1 as the input signal and the vehicle behavior information X4 as the output signal is A14, and the road surface condition S2 is the input signal and the vehicle behavior information. The transmission function with X1 as the output signal is A21, the road surface state S2 is the input signal, the vehicle behavior information X2 is the output signal, the transmission function is A22, the road surface state S2 is the input signal, and the vehicle behavior information X3 is the output signal. The transmission function is A23, the road surface condition S2 is an input signal, the vehicle behavior information X4 is an output signal, the transmission function is A24, the road surface condition S3 is an input signal, and the vehicle behavior information X1 is an output signal. The transmission function with the road surface condition S3 as the input signal and the vehicle behavior information X2 as the output signal is A32, the transmission function with the road surface condition S3 as the input signal and the vehicle behavior information X3 as the output signal is A33, and the road surface condition S3 is the input signal. The transmission function with the vehicle behavior information X4 as the output signal is A34, the transmission function with the road surface condition S4 as the input signal and the vehicle behavior information X1 as the output signal is A41, and the road surface condition S4 is the input signal and the vehicle behavior information X2 is used. The transmission function as the output signal is A42, the transmission function with the road surface condition S4 as the input signal and the vehicle behavior information X3 as the output signal is A43, the road surface condition S4 is the input signal, and the vehicle behavior information X4 is the output signal. Is A44. In this case, the vehicle behavior information X1 to X4 are known because they are detected by the behavior sensor 10B, and the transfer functions A11 to A44 and the road surface conditions S1 to S4 are unknown. It can be said that the transfer functions A11 to A44 and the road surface states S1 to S4 are calculated based on X1 to X4.

In this case, the road surface condition information acquisition unit 32 calculates the transfer functions A11 to A44 and the road surface conditions S1 to S4 so that all of the following equations (1) to (4) are satisfied. Note that E1, E2, E3, and E4 are coefficients and are set according to the calculation of the transfer functions A11 to A44 and the road surface states S1 to S4.

X1 = A11 ・ S1 ＋ A21 ・ S2 ＋ A31 ・ S3 ＋ A41 ・ S4 ＋ E1 ・ ・ ・ (1)
X2 = A12, S1 + A22, S2 + A32, S3 + A42, S4 + E2 ... (2)
X3 = A13 / S1 + A23 / S2 + A33 / S3 + A43 / S4 + E3 ... (3)
X4 = A14 ・ S1 ＋ A24 ・ S2 ＋ A34 ・ S3 ＋ A44 ・ S4 ＋ E4 ・ ・ ・ (4)

For example, the road surface state information acquisition unit 32 uses regression calculation in which numerical values are substituted into the transfer functions A11 to A44 and the road surface states S1 to S4 while changing the values, so that the equations (1) to (4) are established. , Transfer functions A11 to A44 and road surface conditions S1 to S4 are calculated. The road surface condition information acquisition unit 32 is not limited to determining that the equations (1) to (4) are satisfied when the left side and the right side of the equations (1) to (4) have exactly the same value. When the difference between the left side and the right side of the equations (1) to (4) is within a predetermined range, it is assumed that the equations (1) to (4) are satisfied, and the left side and the right side of the equations (1) to (4) are satisfied. The transfer functions A11 to A44 and the road surface states S1 to S4 may be calculated so that the difference between the two and the above is within a predetermined range.

A specific example of the calculation method of the transfer functions A11 to A44 and the road surface states S1 to S4 such that the equations (1) to (4) are satisfied by the road surface condition information acquisition unit 32 will be described below.

The road surface condition information acquisition unit 32 applies arbitrary values to the transmission functions A11 to A44 and the road surface conditions S1 to S4, executes a calculation to calculate the right side of the equations (1) to (4), and executes the calculation of the equation (1). In all of (4), it is determined whether the difference between the left side (measured value of vehicle behavior information) and the right side (calculated value calculated from the transmission function or road surface condition of vehicle behavior information) is within a predetermined value. Then, the same calculation is performed while changing the values of the transfer functions A11 to A44 and the road surface states S1 to S4, and when the difference between the left side and the right side is within a predetermined value in all of the equations (1) to (4). The transfer functions A11 to A44 and the road surface states S1 to S4 are acquired as the calculation results of the transfer functions A11 to A44 and the road surface states S1 to S4. That is, it can be said that the road surface condition information acquisition unit 32 calculates the transfer functions A11 to A44 and the road surface conditions S1 to S4 by using the method of maximum likelihood estimation. The coefficients E1 to E4 may be randomly set for each calculation by using, for example, a probability distribution.

Further, the candidates of the road surface states S1 to S4 used for the calculation may be extracted as follows. That is, the vehicle behavior information X1 to calculated by substituting the time waveform which is the waveform of the measured values of the vehicle behavior information X1 to X4 continuous in time series and arbitrary values as the road surface states S1 to S4 and the transmission functions A11 to A44. The time waveforms of the calculated values of X4 (that is, the right side of the equations (1) to (4)) are created, and the time waveforms are compared. Then, when the difference in the shape of the time waveform is small, the road surface states S1 to S4 used for the time waveform are used as candidates for the road surface states S1 to S4 used for the calculation. Any judgment criteria may be used to judge whether the difference in the shape of the time waveform is small.

Further, in the above description, the case where the road surface states S1 to S4 are unknown and both the road surface state and the transfer function are calculated is taken as an example, but the transfer functions A11 to A44 are used by using the known road surface states S1 to S4. May be calculated in advance. That is, in this case, the vehicle 10 is made to travel on a road whose road surface condition is known to acquire vehicle behavior information X1 to X4. Then, the acquired vehicle information X1 to X4 are substituted into the left side of the equations (1) to (4), and the known road surface conditions S1 to S4 are substituted into the right side of the equations (1) to (4). The transfer functions A11 to A44 are calculated by using the method of maximum likelihood estimation as described above. After that, when the vehicle information X1 to X4 is acquired by driving on a road whose road surface condition is unknown, the vehicle information X1 to X4 and the transmission functions A11 to A44 become known. Can calculate the road surface conditions S1 to S4 of an unknown road. By calculating the transfer functions A11 to A44 in advance using the known road surface conditions S1 to S4 in this way, the calculation load can be reduced.

Further, in the above description, the case where the number of tires is four has been described as an example, but when the number of tires is generalized to n, all of the following formulas (A1) to (An) are used. It can be said that the transfer functions A11 to Ann and the road surface states S1 to Sn are calculated so that the above is satisfied. The calculation method is the same as the above description. Note that n is an integer of 2 or more, and for example, the transfer function A1n is a transfer function that uses the road surface state S1 as an input signal and the vehicle behavior information Xn as an output signal.

X1 = A11 ・ S1 + ・ ・ ・ + An1 ・ Sn + E1 ・ ・ ・ (A1)
・ ・ ・
Xn = A1n · S1 + ... + Ann · Sn + En ... (An)

In the above description, the case where the tire TR and the behavior sensor 10B are four has been described as an example, but the road surface condition information acquisition unit 32 is described below when the tire TR and the behavior sensor 10B are two or more. In other words, the road surface condition is calculated as follows. That is, in the road surface state information acquisition unit 32, the first road surface state (for example, the road surface state S1) and the second road surface state (for example, the road surface state S2) affect the first vehicle behavior information (for example, vehicle behavior information X1). Moreover, by assuming that the first road surface state and the second road surface state affect the second vehicle behavior information (for example, vehicle behavior information X2), the relationship between the first road surface state and the first vehicle behavior information is shown. The first transfer function (for example, transfer function A11), the second transfer function (for example, transfer function A21) showing the relationship between the second road surface state and the first vehicle behavior information, and the first road surface state and the second vehicle behavior information. The third transfer function (for example, transfer function A12) showing the relationship between the above and the fourth transfer function (for example, transfer function A22) showing the relationship between the second road surface state and the second vehicle behavior information are estimated, and the first road surface is estimated. The state and the second road surface state are calculated.

The road surface condition information acquisition unit 32 executes the above-mentioned processing for each group of vehicle behavior information sequentially detected by the vehicle 10 to calculate the road surface condition. The group of vehicle behavior information is vehicle behavior information detected at the same timing by a plurality of behavior sensors 10B, and can be said to be vehicle behavior information associated with the same vehicle position information. That is, in the above example, the vehicle behavior information X1, X2, X3, and X4 are vehicle behavior information detected at the same timing (associated with the same vehicle position information). The road surface condition information acquisition unit 32 can calculate the road surface condition for each position of the road R along the traveling direction of the vehicle 10 by calculating the road surface condition for each group of vehicle behavior information. However, the road surface condition information acquisition unit 32 may calculate the road surface condition by using the vehicle behavior information detected at different timings (using a plurality of vehicle behavior information associated with different vehicle position information). That is, the vehicle behavior information X1, X2, X3, X4 may be vehicle behavior information detected at different timings (associated with different vehicle position information).

The method of estimating the transfer function and calculating the road surface condition is not limited to the above description, and the road surface condition information acquisition unit 32 estimates the transfer function by an arbitrary method using a plurality of vehicle behavior information. The road surface condition may be calculated.

(Processing flow)
Next, the flow of the road surface condition calculation method described above will be described with reference to the flowchart. FIG. 6 is a flowchart illustrating a calculation flow of the road surface condition according to the present embodiment. As shown in FIG. 6, the arithmetic unit 14 acquires the vehicle behavior information detected by the plurality of behavior sensors 10B by the vehicle behavior information acquisition unit 30 (step S10). Then, the arithmetic unit 14 estimates a transfer function indicating the relationship between the vehicle behavior information and the road surface condition based on the plurality of vehicle behavior information acquired by the vehicle behavior information acquisition unit 30, and calculates the road surface condition (step S12). ). The arithmetic unit 14 executes these processes for each group of vehicle behavior information, and calculates the road surface state for each position of the road R along the traveling direction of the vehicle 10.

(effect)
As described above, the arithmetic unit 14 according to the present embodiment includes the vehicle behavior information acquisition unit 30 and the road surface condition information acquisition unit 32. The vehicle behavior information acquisition unit 30 acquires vehicle behavior information indicating the behavior of the vehicle 10 detected by a plurality of behavior sensors 10B (sensors) provided at different positions of the vehicle 10 traveling on the road R. The road surface condition information acquisition unit 32 estimates a transmission function indicating the relationship between the road surface condition of the road R as an input and the vehicle behavior information as an output based on a plurality of vehicle behavior information, thereby estimating the road surface of the road R. Acquires road surface condition information indicating the condition. Here, even when traveling on a road having the same road surface condition, if the detection conditions on the vehicle 10 side are different, the vehicle behavior information changes because the transfer function is different. Therefore, it is difficult to detect the road surface condition based on the vehicle behavior information regardless of the detection conditions on the vehicle 10 side. On the other hand, since the arithmetic unit 14 according to the present embodiment estimates the transfer function based on a plurality of vehicle behavior information, the road surface state is estimated by using the estimated transfer function even when the detection conditions on the vehicle 10 side are different. Can be detected properly. That is, since the arithmetic unit 14 according to the present embodiment estimates the transfer function based on a plurality of vehicle behavior information, the transfer function is not known in advance, regardless of the detection conditions on the vehicle 10 side. It becomes possible to appropriately detect the road surface condition.

Further, the road surface condition information acquisition unit 32 estimates the transfer function by assuming that the road surface conditions at different positions of the road R affect the vehicle behavior information, thereby providing the road surface condition information for each position of the road R. To get. By assuming this, the road surface condition information acquisition unit 32 calculates the transfer function and the road surface information on condition that a signal (vibration or the like) based on the road surface condition at each position is transmitted to all the behavior sensors 10B. .. As a result, the arithmetic unit 14 can estimate the transfer function with higher accuracy and detect the road surface state with higher accuracy regardless of the detection conditions on the vehicle 10 side.

Further, the road surface condition information acquisition unit 32 estimates a transfer function for each combination of the road surface condition and the vehicle behavior information at each position of the road R, and acquires the road surface condition information for each position of the road R. By estimating the transfer function for each combination, the road surface condition information acquisition unit 32 can individually set the modulation degree of the signal when the signal based on the road surface condition is transmitted to the behavior sensor 10B. Therefore, the arithmetic unit 14 can estimate the transfer function with higher accuracy and detect the road surface state with higher accuracy regardless of the detection conditions on the vehicle 10 side.

Further, when the vehicle behavior information detected by the different behavior sensors 10B is used as the first vehicle behavior information and the second vehicle behavior information, and the road surface states at different positions are set as the first road surface state and the second road surface state, the road surface state. In the information acquisition unit 32, the first road surface state (for example, road surface state S1) and the second road surface state (for example, road surface state S2) affect the first vehicle behavior information (for example, vehicle behavior information X1), and the first one. A first transmission function showing the relationship between the first road surface condition and the first vehicle behavior information by assuming that the road surface condition and the second road surface condition affect the second vehicle behavior information (for example, vehicle behavior information X2). (For example, the transmission function A11), the second transmission function (for example, the transmission function A21) showing the relationship between the second road surface state and the first vehicle behavior information, and the relationship between the first road surface state and the second vehicle behavior information are shown. The third transmission function (for example, transmission function A12) and the fourth transmission function (for example, transmission function A22) indicating the relationship between the second road surface state and the second vehicle behavior information are estimated, and the first road surface state and the second are Acquire the road surface condition as road surface condition information. By calculating the road surface condition in this way, the arithmetic unit 14 can estimate the transfer function with higher accuracy and detect the road surface condition with high accuracy regardless of the detection conditions on the vehicle 10 side. Become.

Further, the vehicle behavior information acquisition unit 30 acquires vehicle behavior information detected by the behavior sensor 10B provided on the side (Z direction side) opposite to the tire TR of the vehicle 10 from the suspension SU of the vehicle 10. The arithmetic unit 14 estimates the transfer function with higher accuracy by using the vehicle behavior information detected by the sensor on the Z direction side of the suspension SU, and has high accuracy regardless of the detection conditions on the vehicle 10 side. It is possible to detect the road surface condition.

Further, the vehicle behavior information acquisition unit 30 acquires at least acceleration information of the vehicle 10 as vehicle behavior information. By using acceleration as vehicle behavior information, it is possible to estimate the transfer function with higher accuracy and detect the road surface condition with higher accuracy regardless of the detection conditions on the vehicle 10 side.

The road surface condition is an index indicating the degree of unevenness of the road surface of the road R. By using an index indicating the degree of unevenness of the road surface as the road surface condition, it is possible to appropriately determine the condition of the road surface.

Although the embodiments and examples of the present invention have been described above, the embodiments are not limited by the contents of these embodiments and the like. Further, the above-mentioned components include those that can be easily assumed by those skilled in the art, those that are substantially the same, that is, those in a so-called equal range. Further, the above-mentioned components can be combined as appropriate. Further, various omissions, replacements or changes of the components can be made without departing from the gist of the above-described embodiment or the like.

1 Detection system 10 Vehicle 10B Behavior sensor (sensor)
12 Measurement data acquisition device 14 Arithmetic logic unit 30 Vehicle behavior information acquisition unit 32 Road surface condition information acquisition unit R Road TR Tire

Claims (5)

A vehicle behavior information acquisition unit that acquires vehicle behavior information indicating the behavior of the vehicle detected by a plurality of sensors provided at different positions of the vehicle traveling on the road.
Road surface condition information indicating the road surface condition of the road by estimating a transmission function indicating the relationship between the road surface condition as an input and the vehicle behavior information as an output based on the plurality of vehicle behavior information. Road surface condition information acquisition unit to acquire
Including arithmetic unit. The road surface condition information acquisition unit estimates the transmission function by assuming that the road surface conditions at different positions of the road affect the vehicle behavior information, thereby providing road surface condition information for each position of the road. The arithmetic unit according to claim 1. The road surface condition information acquisition unit estimates the transmission function for each combination of the road surface condition at each position of the road and the vehicle behavior information, and acquires the road surface condition information for each position of the road. , The arithmetic unit according to claim 2. When the vehicle behavior information detected by different sensors is X1, X2, X3, X4, and the road surface conditions at different positions are S1, S2, S3, S4.
The road surface condition information acquisition unit calculates the road surface condition information by calculating transfer functions A11 to A44 and vehicle behavior information S1 to S4 such that all of the following equations (1) to (4) are satisfied. , The arithmetic unit according to claim 3.
X1 = A11 ・ S1 ＋ A21 ・ S2 ＋ A31 ・ S3 ＋ A41 ・ S4 ＋ E1 ・ ・ ・ (1)
X2 = A12, S1 + A22, S2 + A32, S3 + A42, S4 + E2 ... (2)
X3 = A13 / S1 + A23 / S2 + A33 / S3 + A43 / S4 + E3 ... (3)
X4 = A14 ・ S1 ＋ A24 ・ S2 ＋ A34 ・ S3 ＋ A44 ・ S4 ＋ E4 ・ ・ ・ (4)
Here, the transmission function with S1 as the input signal and X1 as the output signal is A11, the transmission function with S1 as the input signal and X2 as the output signal is A12, and S1 is the input signal and X3 is the output signal. Is A13, S1 is an input signal, X4 is an output signal, the transmission function is A14, S2 is an input signal, X1 is an output signal, S2 is an input signal, and X2 is an output signal. The function is A22, the transmission function with S2 as the input signal and X3 as the output signal is A23, the transmission function with S2 as the input signal and X4 as the output signal is A24, and S3 is the input signal and X1 is the output signal. The transmission function is A31, S3 is the input signal, X2 is the output signal, the transmission function is A32, S3 is the input signal, X3 is the output signal, S3 is the input signal, and X4 is the output signal. The transmission function is A34, S4 is an input signal, X1 is an output signal, A41 is, S4 is an input signal, X2 is an output signal, S4 is an input signal, and X3 is an output signal. The transfer function is A43, S4 is an input signal, X4 is an output signal, A44, and E1 to E4 are coefficients. A step of acquiring vehicle behavior information indicating the behavior of the vehicle detected by a plurality of sensors provided at different positions of the vehicle traveling on the road.
Road surface condition information indicating the road surface condition of the road by estimating a transmission function indicating the relationship between the road surface condition as an input and the vehicle behavior information as an output based on the plurality of vehicle behavior information. And the steps to get
Let the computer execute the calculation method, including
program.

Images