Information processing apparatus, vehicle, information processing method, and non-transitory storage medium

Abstract

The present disclosure provides an information processing device, a vehicle, an information processing method, and a non-transitory storage medium. The information processing method includes determining whether at least one condition is satisfied, and calculating a feature amount on softness of a tire when all of the at least one condition is satisfied. The at least one condition includes at least one of a first condition that an absolute value of an angular velocity of a steering wheel is less than a first reference value, and a second condition that an absolute value of a vector sum of vehicle accelerations of a vehicle is less than a second reference value, the vehicle including the steering wheel and a plurality of wheels each provided with the tire.

Description

Technical Field

[0001] This disclosure relates to information processing apparatus, vehicles, information processing methods, and non-transitory storage media. Background Technology

[0002] Japanese Unexamined Patent Application Publication No. 2002-221527 (JP 2002-221527 A) discloses a device for accurately detecting tire wear. This device detects tire wear based on the average of the linear regression coefficients of the vehicle's acceleration / deceleration and the slip ratio of the front and rear wheels. Summary of the Invention

[0003] Typically, various sensors are attached to a vehicle. It is conceivable to estimate changes in the condition of vehicle components based on data acquired from these sensors. In particular, tires may undergo changes in condition due to their deterioration (wear), replacement, etc. Therefore, there is a need for estimating tire changes in condition with high accuracy (see, for example, JP 2002-221527 A).

[0004] This disclosure provides techniques for estimating changes in tire condition with high accuracy.

[0005] The first aspect of this disclosure relates to an information processing device. The information processing device is mounted on a vehicle including a steering wheel and a plurality of wheels, each equipped with tires. The information processing device includes a processor. The processor is configured to calculate a characteristic quantity relating to the suppleness of the tires when at least one condition is met. The at least one condition includes at least one of a first condition and a second condition. The first condition is that the absolute value of the angular velocity of the steering wheel is less than a first reference value, and the second condition is that the absolute value of the vector sum of the accelerations of the vehicle is less than a second reference value.

[0006] In the first embodiment, the information processing device, the steering wheel, and the wheels may be included in the vehicle.

[0007] In the first approach, the at least one condition may include both the first condition and the second condition.

[0008] In the first scheme, the at least one condition may further include a third condition that the absolute value of the steering wheel angle is less than a third reference value.

[0009] In the first embodiment, the at least one condition may further include a fourth condition that the speed of the vehicle is within a predetermined range.

[0010] The first approach calculates characteristic quantities while ensuring that the force applied to the tire is within a certain range (i.e., the force applied to the tire does not fluctuate), thus enabling accurate estimation of tire condition changes.

[0011] In the first embodiment, the wheel may include a drive wheel and a driven wheel. The processor may be configured to calculate the ratio of the rotational speed ratio between the drive wheel and the driven wheel to the acceleration in the longitudinal direction of the vehicle as the characteristic quantity.

[0012] With the above configuration, changes in tire condition, especially changes in softness, can be estimated with high accuracy.

[0013] In the first embodiment, the processor may be configured to accumulate the difference from an initial value of the ratio at a predetermined time, and output a signal indicating a gradual change in the softness of the tire when the accumulated result exceeds a first threshold.

[0014] The above configuration clearly indicates how the tire's softness has changed (i.e., whether the change is gradual or rapid).

[0015] In the first scheme, when the difference between the previous value and the current value of the ratio exceeds a second threshold, the processor can be configured to output a signal indicating a rapid change in the softness of the tire.

[0016] The above configuration allows you to specify how the tire's softness has changed (i.e., whether the change is gradual or rapid).

[0017] The second aspect of this disclosure is an information processing method. The information processing method includes determining whether at least one condition is met, and calculating a characteristic quantity relating to the suppleness of the tire when all of the at least one condition is met. The at least one condition includes at least one of a first condition and a second condition. The first condition is that the absolute value of the angular velocity of the steering wheel is less than a first reference value, and the second condition is that the absolute value of the vector sum of the vehicle's accelerations is less than a second reference value. The vehicle includes the steering wheel and a plurality of wheels, each equipped with the tire.

[0018] The second approach, similar to the first, enables high-precision estimation of tire condition changes.

[0019] The third aspect of this disclosure is a non-transitory storage medium. The non-transitory storage medium stores instructions executable by one or more processors in a computer and causing said processors to perform functions. These functions include determining whether at least one condition is met, and calculating a characteristic quantity relating to the suppleness of the tire when all of said at least one condition is met. The at least one condition includes at least one of a first condition and a second condition. The first condition is that the absolute value of the angular velocity of the steering wheel is less than a first reference value, and the second condition is that the absolute value of the vector sum of the vehicle's accelerations is less than a second reference value. The vehicle includes the steering wheel and a plurality of wheels, each equipped with the tire.

[0020] The third approach, similar to the first approach, enables high-precision estimation of tire condition changes.

[0021] Each of the methods disclosed herein enables the estimation of tire condition changes with high accuracy. Attached Figure Description

[0022] The features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, wherein like reference numerals denote like elements, and wherein:

[0023] Figure 1 A diagram illustrating the overall configuration of a vehicle management system according to an embodiment of the present disclosure;

[0024] Figure 2 This diagram illustrates an example of a vehicle configuration.

[0025] Figure 3 A block diagram illustrating a typical hardware configuration of a braking ECU;

[0026] Figure 4 A diagram used to describe the systems included in a vehicle;

[0027] Figure 5 A diagram used to describe an overview of the processes performed by an information processing device;

[0028] Figure 6 A functional block diagram of an information processing device;

[0029] Figure 7 A graph used to describe the slope;

[0030] Figure 8 A diagram illustrating a testing method used to describe the gradual change in tire softness;

[0031] Figure 9 A diagram illustrating a detection method for describing rapid changes in tire softness; and

[0032] Figure 10 This is a flowchart illustrating the process performed by an information processing device. Detailed Implementation

[0033] In the following description, embodiments will be described in detail with reference to the accompanying drawings. Identical or corresponding parts in the drawings are indicated by the same reference numerals and their descriptions will not be repeated.

[0034] Example

[0035] Overall system configuration

[0036] Figure 1 This diagram illustrates the overall configuration of a vehicle management system according to an embodiment of the present disclosure. The vehicle management system 10 includes a plurality of vehicles 1 and a data center 9.

[0037] Vehicle 1 is, for example, a battery electric vehicle (BEV). However, there is no particular limitation on the power source of Vehicle 1. Vehicle 1 can be a vehicle equipped with an engine (so-called conventional vehicle), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a fuel cell electric vehicle (FCEV). [The remaining text appears to be incomplete and requires further context.] Figures 2 to 4 The configuration of vehicle 1 is described in the text.

[0038] Data center 9 manages data from multiple vehicles 1. Connecting data center 9 allows for bidirectional communication with vehicles 1 via communication network NW. Data center 9 collects data from each vehicle 1. Data center 9 also provides necessary data (such as update programs) to each vehicle 1 and sends various commands to each vehicle 1. Data center 9 includes server 91, vehicle information database 92, and communication device 93.

[0039] Server 91 is a processing circuit that includes a processor 911 and a memory 912. Server 91 collects data from each vehicle 1. Server 91 then processes the collected data and stores the processing results in the vehicle information database 92. Details of the data collected by server 91 and the processing performed by server 91 will be described later. Communication device 93 enables communication between server 91 and communication network NW.

[0040] Vehicle Configuration

[0041] Figure 2This diagram illustrates an example configuration of vehicle 1. Vehicle 1 includes an Advanced Driver Assistance System (ADAS) - Electronic Control Unit (ECU) 11, Braking ECU 12, Central ECU 13, and Data Communication Module (DCM) 2. The ADAS-ECU 11, Braking ECU 12, and various other ECUs (not shown) included in the actuator system 300 (described later) are communicatively connected to the Central ECU 13 via a communication bus such as a Controller Area Network (CAN). Alternatively, the Central ECU 13 may have a gateway function to relay communication between the ECUs.

[0042] ADAS-ECU 11 controls Advanced Driver Assistance System 100 (see...) Figure 4 The advanced driver assistance system 100 is configured to perform various functions to assist in driving the vehicle 1.

[0043] The braking ECU 12 performs braking control of the vehicle 1. In this embodiment, the braking ECU 12 includes an information processing unit 200. The information processing unit 200 obtains various information from a motion manager that manages the vehicle's motion and a vehicle stability control (VSC) system that stabilizes the vehicle's attitude. The information processing unit 200 requests the actuator system 300 to move the vehicle 1 according to a kinematic plan set in at least one of the multiple applications of the advanced driver assistance system 100. The detailed configuration of the information processing unit 200 will be described later.

[0044] The information processing device 200 can be implemented in another ECU (e.g., a steering ECU or an electric generator ECU, not shown) that is different from the brake ECU 12. Alternatively, the information processing device 200 can be implemented as a single ECU. The ECU on which the information processing device 200 is installed (the brake ECU 12 in this embodiment) is an example of an "information processing device" according to the present disclosure. An example of an "information processing device" according to the present disclosure can be a central ECU 13.

[0045] The central ECU 13 is communicatively connected to DCM 2. DCM 2 is a communication module configured to wirelessly communicate with external devices via a communication network NW. As a result, communication between vehicle 1 and data center 9 (see...) is realized. Figure 1 Two-way communication between ECUs. In this embodiment, the central ECU 13 sends data received from ECUs such as the brake ECU 12 to the data center 9 via the DCM 2.

[0046] The central ECU 13 includes a memory (not shown) in which programs are stored. These programs include those read from various ECUs (e.g., operating systems and applications) when the vehicle 1's system starts. When an updated program is received from the data center 9, the central ECU 13 updates the programs stored in the memory.

[0047] Figure 3 This diagram illustrates a typical hardware configuration of the brake ECU 12. The brake ECU 12 has a processor 121, a memory 122, and an input / output interface (I / O) 123. The processor 121 is, for example, a central processing unit (CPU). The processor 121 performs various arithmetic operations according to a program. The memory 121 includes a read-only memory (ROM) 122A, a random access memory (RAM) 122B, and flash memory 122C. The memory 122 stores programs (e.g., operating systems and application programs) executed by the processor 121. The input / output interface 123 is configured to exchange information with other ECUs. Although not described again, the hardware configurations of the other ECUs are the same.

[0048] Figure 4 This diagram illustrates the systems included in vehicle 1. Vehicle 1 also includes an actuator system 300, multiple (four in this example) wheels 400, and a sensor array 500. Information processing unit 200 is connected to advanced driver assistance system 100, actuator system 300, and sensor array 500.

[0049] Advanced driver assistance system 100 includes, for example, Adaptive Cruise Control (ACC) 101, Automatic Speed ​​Limiter (ASL) 102, Lane Keeping Assist (LKA) 103, Pre-Crash Safety (PCS) 104, and Lane Departure Alert (LDA). Although not shown, advanced driver assistance system 100 may include an Automated Driving System (ADS).

[0050] The actuator system 300 includes a plurality of actuators and is configured to fulfill the motion requirements of the vehicle 1 output from the information processing device 200. The actuator system 300 includes, for example, a steering system 31, a braking system 32, and a powertrain system 33.

[0051] The steering system 31 includes, for example, rack and pinion electric power steering (EPS) and controls the steering angle (steering wheel angle) of the steering wheel of the vehicle 1.

[0052] Braking system 32 controls multiple braking devices (not shown) disposed on each wheel 400 of vehicle 1. The braking devices include, for example, disc brake systems that operate using hydraulic pressure adjusted by actuators. Braking system 32 may include an electric parking brake (EPB) (not shown) that locks the wheels 400 by actuation of an actuator. Braking system 32 may include a parking (P) locking system (not shown) that controls a P locking device disposed in the transmission of vehicle 1.

[0053] The powertrain 33 is configured to use a shifting device (not shown) to switch gears and to use an electric generator (not shown) to control the driving force in the direction of travel of the vehicle 1. The powertrain 33 rotates the drive wheels 41, 42 (described later) to apply driving force to the vehicle 1, causing the vehicle 1 to move.

[0054] For example, the four wheels 400 include drive wheels 41 and 42 and driven wheels 43 and 44. In this example, the front wheels are drive wheels and the rear wheels are driven wheels. However, the wheel arrangement is not limited to the front wheels being drive wheels and the rear wheels being driven wheels.

[0055] The sensor group 500 detects driving operation variables and driving state variables of the vehicle 1. For example, the sensor group 500 includes a steering sensor 51, first to fourth wheel speed sensors 521 to 524, and an acceleration sensor 53.

[0056] For example, the steering sensor 51 detects the rotation angle of the pinion connected to the rotating shaft of the actuator as the steering wheel angle θ. The steering sensor 51 outputs the detected steering wheel angle θ to the information processing device 200. The steering sensor 51 detects the steering wheel angular velocity ω and outputs the steering wheel angular velocity ω to the information processing device 200.

[0057] The first wheel speed sensor 521 detects the drive wheel speed VXFL, which is the rotational speed of the left front drive wheel 41. The second wheel speed sensor 522 detects the drive wheel speed VXFR, which is the rotational speed of the right front drive wheel 42. The third wheel speed sensor 523 detects the driven wheel speed VXRL, which is the rotational speed of the left rear driven wheel 43. The fourth wheel speed sensor 524 detects the driven wheel speed VXRR, which is the rotational speed of the right rear driven wheel 44. Each wheel speed sensor outputs the detected wheel speed to the information processing device 200.

[0058] Accelerometer 53 includes a longitudinal acceleration sensor and a lateral acceleration sensor (both shown). The longitudinal acceleration sensor detects the acceleration GX in the longitudinal direction of vehicle 1 and outputs the detected acceleration GX to the information processing device 200. The lateral acceleration sensor detects the acceleration GY in the lateral direction of vehicle 1 and outputs the detected acceleration GY to the information processing device 200. The information processing device 200 is capable of calculating the vector sum of the accelerations GX and GY in both the longitudinal and lateral directions. Hereinafter, the vector sum will be referred to as the "composite acceleration G".

[0059] Although not shown, the sensor group 500 may also include other sensors such as cameras, millimeter-wave radar, laser imaging detection and ranging (LiDAR), and gyroscope sensors.

[0060] In this example, it has been described that all sensors included in sensor group 500 directly output their detection results to information processing unit 200. However, any one of these sensors can output its detection result to another ECU. Information processing unit 200 can acquire the sensor detection results via a communication bus or central ECU 13.

[0061] In the vehicle 1 configured as described above, the information processing unit 200 uses data acquired from various sensors included in the sensor group 500 to estimate changes in tire condition. However, the condition of vehicle 1 can change significantly depending on various disturbances, the user's driving style, etc. Noise caused by disturbances and driving style may reduce the accuracy of tire condition change estimation.

[0062] Therefore, in this embodiment, the information processing device 200 estimates tire condition changes when at least one predetermined condition (multiple conditions in this embodiment) is met. More specifically, when all multiple conditions are met, the information processing device 200 calculates characteristic quantities related to tire suppleness. These conditions are set assuming driving conditions where the forces applied to the tire are within a certain range. Although details will be described later, this method allows the characteristic quantities to be calculated after removing noise caused by disturbances, driving style, etc. As a result, tire condition changes can be estimated with high accuracy.

[0063] Information processing device

[0064] Figure 5 This is a diagram illustrating an outline of the processing performed by the information processing apparatus 200. The information processing apparatus 200 includes, for example, a condition determination unit 201, a feature quantity calculation unit 202, and a change detection unit 203.

[0065] The condition determination unit 201 determines whether at least one condition (multiple conditions in this example) for calculating the feature quantity is met based on data from the sensor group 500 regarding driving operation variables and vehicle state quantities. This will be discussed later. Figure 6 The conditions are described in detail. The condition determination unit 201 outputs the condition determination result to the feature quantity calculation unit 202.

[0066] When the conditions for calculating the characteristic quantity are met, the characteristic quantity calculation unit 202 calculates the characteristic quantity using data on driving operation variables and data on vehicle state quantities. (See below for further details.) Figure 6 and Figure 7 The method for calculating the feature quantity is described. The feature quantity calculation unit 202 outputs the calculated feature quantity to the change detection unit 203.

[0067] The change detection unit 203 detects changes in the tire's condition based on characteristic quantities related to tire flexibility. (See below for further details.) Figure 6 , Figure 8 and Figure 9 A method for detecting changes in tire condition is described. The change detection unit 203 outputs data indicating the detected changes in tire condition to the central ECU 13.

[0068] The central ECU 13 sends data indicating changes in tire condition to the data center 9 via the DCM 12. As a result, the data is accumulated in the vehicle information database 92 in the data center 9.

[0069] Figure 6 This is a functional block diagram of the information processing device 200.

[0070] Condition determination

[0071] The condition determination unit 201 receives data from the sensor group 500 as quantities relating to driving operation variables, namely, steering wheel angle θ and steering wheel angular velocity ω, and also receives data as quantities relating to vehicle state variables, namely, four wheel speeds (drive wheel rotation speeds VXFL, VXFR and driven wheel rotation speeds VXRL, VXRR) and accelerations GX, GY. Upon receiving a trigger signal (e.g., a signal indicating the end of a control cycle), the condition determination unit 201 determines, based on this data, whether the conditions used to calculate the characteristic quantities are met. More specifically, the condition determination unit 201 determines, in this example, whether the following four conditions are met.

[0072] The condition determination unit 201 determines whether the speed (vehicle speed) V of vehicle 1 is within the range defined by the upper limit value UL and the lower limit value LL (see formula (1) below). As an example, the lower limit value LL is 30 [km / h], and the upper limit value UL is 70 [km / h]. When this condition is met, vehicle 1 travels at a low or medium speed.

[0073] LL ≤ V ≤ UL . . . (1)

[0074] The condition determination unit 201 can calculate the vehicle speed V using known methods. For example, the condition determination unit 201 can calculate the vehicle speed V based on a specific wheel speed among the four wheel speeds. Alternatively, the condition determination unit 201 can calculate the vehicle speed V based on the rotational speed of the drive shaft (not shown).

[0075] The condition determination unit 201 determines whether the absolute value of the steering wheel angle θ is equal to or less than the predetermined reference value θref (see formula (2) below). When the condition is met, the vehicle 1 proceeds straight or turns smoothly.

[0076] |θ| ≤ θref . . . (2)

[0077] The condition determination unit 201 determines whether the absolute value of the steering wheel angular velocity ω is equal to or less than a predetermined reference value ωref (see formula (3) below). When this condition is met, the vehicle 1 travels straight or turns at a roughly constant angular velocity (during uniform circular motion).

[0078] |ω| ≤ ωref . . . (3)

[0079] Condition determination unit 201 determines whether the absolute value of the resultant acceleration G is equal to or less than a predetermined reference value Gref (see formula (4) below). The reference value Gref can be a small value, such as 1 m / s². 2 When this condition is met, vehicle 1 travels at a low or medium speed.

[0080] |G| ≤ Gref . . . (4)

[0081] The above four conditions can be categorized into three attributes. The condition regarding vehicle speed V (Formula (1)) is the premise. The conditions regarding steering wheel angle θ (Formula (2)) and steering wheel angular velocity ω (Formula (3)) are the inputs (cause). The condition regarding the resultant acceleration G (Formula (4)) is the response (result). In particular, the steering wheel angular velocity ω represents the variation of the input. When the steering wheel angular velocity ω changes, the force applied to the tire changes, and as a response, the resultant acceleration G changes. Therefore, the conditions regarding steering wheel angular velocity ω and the condition regarding resultant acceleration G are important for determining whether the force applied to the tire is fluctuating or constant.

[0082] When all of formulas (1) to (4) are satisfied, the condition determination unit 201 turns on the permission flag for calculating the allowed feature quantity. On the other hand, when at least one of formulas (1) to (4) is not satisfied, the condition determination unit 201 turns off the permission flag. The condition determination unit 201 outputs a signal to the feature quantity calculation unit 202 indicating whether the permission flag is turned on or off (ON / OFF).

[0083] Calculation of characteristic quantities

[0084] When the enable flag is on, the feature quantity calculation unit 202 calculates slopes grdL and grdR as feature quantities based on the rotational speeds of the drive wheels VXFL and VXFR, the rotational speeds of the driven wheels VXRL and VXRR, and the longitudinal acceleration GX. Slope grdL is a feature quantity relating to the left tire (drive wheel 41 and driven wheel 43). Slope grdR is a feature quantity relating to the right tire (drive wheel 42 and driven wheel 44).

[0085] Figure 7 This is a graph used to describe the slope grdL. The horizontal axis represents the longitudinal acceleration GX. The vertical axis represents the left wheel speed ratio SL. The wheel speed ratio SL is the ratio of the rotational speeds between the driving wheel 41 and the driven wheel 43, VXFL / VXRL. SL can be set to VXFL / VXRL-1, such that when VXFL = VXRL, the wheel speed ratio SL becomes 0.

[0086] During acceleration, the driving wheel's rotational speed VXFL is higher than the driven wheel's rotational speed VXRL (VXFL / VXRL>1), while during deceleration, the driving wheel's rotational speed VXFL is lower than the driven wheel's rotational speed VXRL (VXFL / VXRL<1). Therefore, the relationship between the longitudinal acceleration GX and the wheel speed ratio SL is as follows: Figure 7 The relationship shown is a linear increase.

[0087] The characteristic quantity calculation unit 202 calculates the ratio between the left wheel speed ratio SL (=VXFL / VXRL) and the longitudinal acceleration GX as the slope grdL, as shown in the formula (5) below. The slope can be called the inclination of the straight line.

[0088] grdL = SL / GX ... (5)

[0089] Although not shown, the characteristic quantity calculation unit 202 calculates the slope grdR in a similar manner. The slope grdR is the ratio of the right wheel speed ratio SR (=VXFR / VXRR) to the longitudinal acceleration GX (see Formula (6) below). The slopes grdL and grdR are examples of "ratios" according to this disclosure.

[0090] grdR = ​​SR / GX ... (6)

[0091] When plotting a straight line representing Hooke's law (F = kx (k: spring constant)) on a graph with the deformation amount x of the spring on the horizontal axis and the elastic force F of the spring on the vertical axis, the slope of the straight line represents the spring constant k. The larger the slope, the larger the spring constant k, that is, the stiffer the spring. This analogy is used to conceptually describe the physical meaning of the slope.

[0092] When the mass m is constant in the equation of motion (F = ma), the acceleration a is in a proportional relationship with the force F, so the acceleration can be read as the force. For this reason, Figure 7 the acceleration GX on the horizontal axis of Figure 7 is considered to represent the longitudinal force applied to the ground contact surface of the tire. On the other hand, the rotational speed difference between the driving wheel and the driven wheel is caused by the slip of the wheel (mainly the driving wheel). Compared with other cases, the slipping wheel stretches more. Thus, it is considered that the wheel speed ratio SR on the vertical axis represents the deformation amount of the tire in the rotational direction. Therefore, based on the above analogy of the spring, Figure 7 the slope in Figure 7 can be said to be a parameter regarding the tire stiffness, such as the spring constant. However, in

[0093] and the graph showing Hooke's law, the relationship between the vertical axis and the horizontal axis is reversed. Therefore,

[0094] a large slope of the Figure 6 tire means that the tire has a high degree of flexibility. As the tire deteriorates and the tire flexibility decreases, the slope becomes smaller. When the acceleration GX is small in the forward direction (for example, 0.975 < GX < 1.025), when SL > SLPmax, SL can be set equal to SLPmax, and when SL < SLPmin, SL can be set equal to SLPmin. When the acceleration GX is small in the backward direction (for example, -1.025 < GX < -0.975), when SL > SLNmax, SL can be set to SLNmax, and when SL < SLNmin, SL can be set to SLNmin. Then, the maximum slope value grdLmax = (SLPmax - SLNmin), and the minimum slope value grdLmin = (SLPmin - SLNmax). The characteristic quantity calculation unit 202 can calculate the value between the maximum slope value grdLmax and the minimum slope value grdLmin as the slope grdL.

[0094] Refer to Figure 6The feature calculation unit 202 stores the calculated feature quantities (slopes grdL and grdR) in memory 122 in association with the calculation order. In this example, the number of trips of vehicle 1 is used as the calculation order. For example, the feature quantity is calculated once for each trip. However, the feature calculation unit 202 can calculate the feature quantity multiple times for a single trip, or it can calculate the feature quantity once for multiple trips. Alternatively, the feature calculation unit 202 can calculate the feature quantity each time a specific time has elapsed, or it can calculate the feature quantity each time vehicle 1 travels a specific distance. The feature calculation unit 202 outputs the calculated slopes grdL and grdR, as well as the number of trips, to the change detection unit 202.

[0095] Change detection

[0096] The change detection unit 203 calculates the change in tire softness based on the slopes grdL and grdR. More specifically, the change detection unit 203 detects the change in the softness of the left tire based on the slope grdL, and detects the change in the softness of the right tire based on the slope grdR. The change in tire softness can include gradual changes in tire softness expected due to tire wear, etc., and rapid changes in tire softness expected due to tire replacement, etc.

[0097] Figure 8 This is a graph illustrating a testing method used to describe the gradual change in tire softness. The horizontal axis represents the number of trips. The vertical axis represents the cumulative result of the slope (slope grdL or slope grdR).

[0098] The change detection unit 203 performs calculations on the slope grdL and the slope grdR, respectively. The calculation of slope grdL will be described below as an example, but the same applies to the calculation of slope grdR.

[0099] The change detection unit 203 stores the initial value of the slope grdL, grdL(0) (the slope of the first trip). For each trip, the change detection unit 203 accumulates the difference (grdL(n) - grdL(0)) (usually a negative value) between the current value of the slope grdL(n) and the initial value of the slope grdL(0) into the previous slope accumulation result. Subsequently, the change detection unit 203 determines whether the slope accumulation result ΣgrdL is equal to or less than the first threshold TH1 (see formula (7) below).

[0100] ΣgrdL≤TH1...(7)

[0101] Although the first threshold TH1 can be a fixed value, it can be set according to the initial value of the slope, grdL(n). For example, the first threshold TH1 can be set as α times (α<1) of the initial value of the slope, grdL(n).

[0102] When the cumulative slope result ΣgrdL is equal to or less than the first threshold TH1, the change detection unit 203 determines that the left tire's softness has gradually changed and switches the gradual change detection flag to ON. On the other hand, when the cumulative slope result ΣgrdL exceeds the first threshold TH1, the change detection unit 203 determines that the left tire's softness has not yet gradually changed and keeps the gradual change detection flag OFF. The change detection unit 203 outputs a signal indicating the ON / OFF of the gradual change detection flag to the central ECU 13.

[0103] Figure 9 This is a graph illustrating a detection method for describing rapid changes in tire softness. The horizontal axis represents the number of trips. The vertical axis represents the slope (slope grdL or slope grdR). Although slope grdL is described as an example here, the same applies to slope grdR.

[0104] For example, for each trip, the change detection unit 203 stores the slope grdL immediately after the trip begins. The change detection unit 203 determines whether the difference ΔgrdL = grdL(n) - grdL(n-1) between the current value grdL(n) and the previous value grdL(n-1) is equal to or greater than the second threshold TH2 (see formula (8) below).

[0105] ΔgrdL ≥ TH2 . . . (8)

[0106] When the difference ΔgrdL is equal to or greater than the second threshold TH2, the change detection unit 203 determines that a rapid change in the softness of the left tire has occurred and switches the rapid change detection flag to ON. On the other hand, when the difference ΔgrdL is less than the second threshold TH2, the change detection unit 203 determines that the softness of the left tire has not yet changed rapidly and keeps the rapid change detection flag OFF. The change detection unit 203 outputs a signal indicating the ON / OFF state of the rapid change detection flag to the central ECU 13.

[0107] review Figure 5The central ECU 13 transmits the data (gradual change detection markers and rapid change detection markers) received from the change detection unit 203 to the data center 9 via the DCM 2. The data transmitted from the DCM 2 to the data center 9 may also include slopes grdL and grdR as characteristic quantities, and may also include cumulative slope results. This data is preferably associated with the processing time. The data center 9 accumulates this data in the vehicle information database 92 as correlated summary data. As a result, the data center 9 can obtain statistics on the changes in the condition of each tire of the vehicle 1. Specifically, when the gradual change detection marker is activated, the data center 9 can determine that a change in tire condition (deterioration) has occurred. Furthermore, when the rapid change detection marker is activated, the data center 9 can determine that a tire replacement has occurred. The data center 9 can also use these statistics as statistics on changes in the driver's driving behavior characteristics.

[0108] Processing flow

[0109] Figure 10 A flowchart illustrating the process performed by the information processing device 200 is provided. In this embodiment, the series of processes illustrated in the flowchart are repeatedly executed by the brake ECU 12 in each predetermined control cycle. Each step is implemented by software processing by the brake ECU 12, but can also be implemented by hardware processing by circuitry arranged within the brake ECU 12. Hereinafter, steps will be abbreviated as S.

[0110] In S1, the brake ECU 12 acquires data from the sensor group 500. Specifically, the brake ECU 12 acquires the steering wheel angle θ, steering wheel angular velocity ω, drive wheel rotation speeds VXFL and VXFR, driven wheel rotation speeds VXRL and VXRR, longitudinal acceleration GX, and lateral acceleration GY.

[0111] In steps S2 to S5, the braking ECU 12 determines whether four conditions for calculating characteristic quantities are met. Specifically, in S2, the braking ECU 12 determines whether the vehicle speed V is within the range between the lower limit LL and the upper limit UL (see Formula (1) for an example of the fourth condition according to this disclosure). In S3, the braking ECU 12 determines whether the absolute value of the steering wheel angle θ is equal to or less than the reference value θref (see Formula (2), an example of the third condition according to this disclosure). In S4, the braking ECU 12 determines whether the absolute value of the steering wheel angular velocity ω is equal to or less than the reference value ωref (see Formula (3), an example of the first condition according to this disclosure). In S5, the braking ECU 12 determines whether the absolute value of the composite acceleration G is equal to or less than the reference value Gref (see Formula (4), an example of the second condition according to this disclosure). The order of steps S2 to S5 can be changed.

[0112] When all conditions S2 to S5 are met (yes in S2, S3, S4, and S5), the braking ECU 12 proceeds to S6. Conversely, if at least one of the conditions S2 to S5 is not met (no in S2, no in S3, no in S4, or no in S5), the braking ECU 12 does not execute subsequent steps and terminates the process without executing the remaining steps.

[0113] All steps S2 to S5 are not necessary. The brake ECU 12 can perform at least one of S4 and S5. However, by performing both S4 and S5, it is possible to more reliably ensure that the force applied to the tire is within a certain range (the force applied to the tire does not fluctuate). Furthermore, by performing one or both of steps S2 and S3 in addition to steps S4 and S5, it is possible to more reliably ensure that the force applied to the tire is within a certain range. As a result, the accuracy of the estimation of tire condition changes can be improved.

[0114] In S6, the braking ECU 12 calculates the left slope grdL and right slope grdR as characteristic quantities. Because in Figure 7 The method for calculating the slopes grdL and grdR has already been described in detail, so it will not be repeated here. The braking ECU 12 stores the calculated slopes grdL and grdR in memory 122 in association with the corresponding time. The next steps S7 to S12 are executed for the left slope grdL and the right slope grdR, respectively. The left slope grdL will be described representatively below.

[0115] In S7, the brake ECU 12 calculates the cumulative slope result ΣgrdL calculated in S6. Then, the brake ECU 12 determines whether the cumulative slope result ΣgrdL is equal to or less than a first threshold TH1. This is because earlier, when referring to... Figure 8 These processes have already been described, so they will not be repeated. When the cumulative slope result ΣgrdL is less than or equal to the first threshold TH1 ("Yes" in step S7), the brake ECU 12 activates the gradual change detection flag (S8), and at the same time, when the cumulative slope result ΣgrdL is greater than the first threshold TH1 ("No" in S7), the gradual change detection flag is deactivated (S9).

[0116] In S10, the brake ECU 12 calculates the slope difference ΔgrdL calculated in S6. Then, the brake ECU 12 determines whether the slope difference ΔgrdL is greater than the second threshold TH2. Because in Figure 9These processes are described in the previous section, so they will not be repeated here. When the slope difference ΔgrdL is equal to or greater than the second threshold TH2 (yes in S10), the brake ECU 12 activates the rapid change detection flag (S11), and when the slope difference ΔgrdL is less than the second threshold TH2 (no in S10), the rapid change detection flag is deactivated (S12).

[0117] In S13, the braking ECU 12, along with the calculated sequence (e.g., number of trips, timestamps, and mileage), outputs markers (on / off for gradually changing detection markers and on / off for rapidly changing detection markers) and characteristic quantities (slope grdL, grdR) to the central ECU 13. The braking ECU 12 may also output the cumulative slope result ΣgrdL and / or the slope difference ΔgrdL. This completes the series of processes.

[0118] As described above, in this embodiment, four conditions can be considered when calculating the characteristic quantities (slopes grdL and grdR). These four conditions are that the absolute value of the steering wheel angle θ, the steering wheel angular velocity ω, the vehicle speed V, and the vector sum of the acceleration (composite acceleration) G are all less than predetermined reference values ​​(or within predetermined reference ranges). When these conditions are met, since the force applied to the tire does not fluctuate (remains essentially constant), the slopes grdL and grdR can be calculated without being affected by noise caused by disturbances, driving style, etc. Through this embodiment, tire condition changes can be estimated with high accuracy.

[0119] The embodiments disclosed herein should be understood in all respects as exemplary rather than restrictive. The scope of this disclosure is indicated by the scope of the claims, not by the description of the embodiments above, and is intended to include all variations within the scope of the claims.

Claims

1. An information processing device installed on a vehicle including a steering wheel and a plurality of wheels, each having tires and including drive wheels and driven wheels, the information processing device being characterized in that it includes... The processor, which is configured as When at least one of the conditions is met, the ratio of the rotational speed between the drive wheel and the driven wheel to the acceleration in the longitudinal direction of the vehicle is calculated as a characteristic quantity, and the ratio decreases as the softness of the tire decreases. The difference between the initial value of the ratio and the predetermined value is accumulated at a predetermined time. When the cumulative result is equal to or less than the first threshold, a signal indicating a gradual change in the softness of the tire is output. as well as When the difference between the previous and current values ​​of the ratio exceeds a second threshold, a signal indicating a rapid change in the softness of the tire is output, wherein: The at least one condition includes at least one of the first condition and the second condition; The first condition is that the absolute value of the angular velocity of the steering wheel is less than a first reference value; and The second condition is that the absolute value of the vector sum of the vehicle's accelerations is less than the second reference value.

2. The information processing device according to claim 1, characterized in that, The at least one condition includes both the first condition and the second condition.

3. The information processing device according to claim 2, characterized in that, The at least one condition also includes a third condition that the absolute value of the steering wheel angle is less than the third reference value.

4. The information processing apparatus according to claim 3, characterized in that, The at least one condition also includes a fourth condition that the vehicle's speed is within a predetermined range.

5. A vehicle, characterized in that... include: The information processing apparatus according to claim 1; steering wheel; as well as Multiple wheels.

6. An information processing method for a vehicle, the vehicle comprising a steering wheel and a plurality of wheels, each equipped with tires and including drive wheels and driven wheels, the information processing method being characterized in that it comprises: Determine whether at least one condition is met; When at least one of the above conditions is met, the ratio of the rotational speed ratio between the drive wheel and the driven wheel to the acceleration in the longitudinal direction of the vehicle is calculated as a characteristic quantity, and the ratio decreases as the softness of the tire decreases. The difference between the initial value of the ratio and the predetermined value is accumulated at a predetermined time. When the cumulative result is equal to or less than the first threshold, a signal indicating a gradual change in the softness of the tire is output. as well as When the difference between the previous and current values ​​of the ratio exceeds a second threshold, a signal indicating a rapid change in the softness of the tire is output, wherein... The at least one condition includes at least one of the first condition and the second condition. The first condition is that the absolute value of the angular velocity of the steering wheel is less than a first reference value, and The second condition is that the absolute value of the vector sum of the vehicle accelerations is less than the second reference value.

7. A non-transitory storage medium storing instructions executable by one or more processors of a computer and causing said one or more processors to execute instructions relating to a function of a vehicle, said vehicle including a steering wheel and a plurality of wheels, each provided with tires and including drive wheels and driven wheels, said function being characterized in that it includes: Determine whether at least one condition is met; When at least one of the above conditions is met, the ratio of the rotational speed ratio between the drive wheel and the driven wheel to the acceleration in the longitudinal direction of the vehicle is calculated as a characteristic quantity, and the ratio decreases as the softness of the tire decreases. The difference between the initial value of the ratio and the predetermined value is accumulated at a predetermined time. When the cumulative result is equal to or less than the first threshold, a signal indicating a gradual change in the softness of the tire is output. as well as When the difference between the previous and current values ​​of the ratio exceeds a second threshold, a signal indicating a rapid change in the softness of the tire is output, wherein... The at least one condition includes at least one of the first condition and the second condition. The first condition is that the absolute value of the angular velocity of the steering wheel is less than a first reference value, and The second condition is that the absolute value of the vector sum of the vehicle accelerations is less than the second reference value.

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