Vehicle driving assistance system and vehicle driving assistance method

Abstract

The present invention provides a vehicle driving assistance system and a vehicle driving assistance method. The driving assistance system executes: a temperature acquisition process to acquire tire temperature; an appropriate value setting process to derive a value that decreases as the tire temperature decreases as a candidate for an appropriate vehicle speed value and sets the appropriate vehicle speed value based on the candidate value; and an assistance process to at least one of report the appropriate vehicle speed value to the driver and decelerate the vehicle if the vehicle speed exceeds the appropriate vehicle speed value.

Description

Technical Field

[0001] The present invention relates to a vehicle driving assistance system and a vehicle driving assistance method. Background Art

[0002] Japanese Patent Application Laid-Open No. 2016-78730 describes an example of vehicle speed control during automatic driving. Specifically, when a vehicle is driven on a curve, the appropriate speed for the vehicle on the curve, i.e., the appropriate speed, is derived based on the curvature of the curve or the driving history of the curve. Summary of the Invention

[0003] The above-mentioned appropriate vehicle speed can vary according to the state of the vehicle when traveling on a curve. Such a problem can occur not only when the vehicle is traveling on a curve, but also when the vehicle is traveling on a straight road.

[0004] <Methods for solving the problem>

[0005] The vehicle driving assistance system for solving the above-mentioned problem is a system that assists the driver in vehicle operation while the vehicle is driving. The driving assistance system includes an execution device. The execution device performs the following processes: temperature acquisition processing for acquiring the temperature of the vehicle's tires, i.e., the tire temperature; appropriate value setting processing for setting the appropriate vehicle speed, i.e., the appropriate vehicle speed value, while the vehicle is driving; and assistance processing for performing at least one of reporting the appropriate vehicle speed value to the driver and decelerating the vehicle when the vehicle speed exceeds the appropriate vehicle speed value. In addition, during the appropriate value setting processing, the execution device derives a value that is smaller as the tire temperature decreases as a candidate value for the appropriate vehicle speed value, and sets the appropriate vehicle speed value based on this candidate value.

[0006] The lower the tire temperature, the weaker the tire's grip. The weaker the tire's grip, the more likely the vehicle's driving stability will deteriorate. Therefore, in the above configuration, a value that decreases as the tire temperature decreases is derived as a candidate for the appropriate vehicle speed value, and the appropriate vehicle speed value is set based on this candidate value. Furthermore, through auxiliary processing, the appropriate vehicle speed value is reported to the driver, or the vehicle is decelerated so that the vehicle speed does not exceed the appropriate vehicle speed value.

[0007] That is, according to the above configuration, a value according to the state of the vehicle can be set as the appropriate vehicle speed value.

[0008] In one aspect of the driving assistance system, the execution device acquires a higher temperature as the tire temperature as the travel distance from the start of the vehicle increases in the temperature acquisition process.

[0009] As the vehicle's travel distance increases, the tire temperature tends to increase. Therefore, in the above configuration, the longer the vehicle's travel distance is, the higher the temperature acquired as the tire temperature.

[0010] One embodiment of the driving assistance system includes a storage device that divides a road on which the vehicle is traveling into a plurality of driving areas and stores the divided roads. The storage device includes a map that stores, for each of the plurality of driving areas, a reference for the appropriate vehicle speed value, i.e., a reference for the appropriate vehicle speed value. Furthermore, the execution device performs a determination process for determining a driving area, i.e., a driving area, in which the vehicle is currently traveling from among the plurality of driving areas. In the appropriate value setting process, the candidate value is derived based on the reference appropriate vehicle speed value corresponding to the driving area and the tire temperature, obtained from the map.

[0011] According to the above configuration, a region where the vehicle is traveling is identified as a driving region from among multiple driving regions. A candidate value for the appropriate vehicle speed value is then derived based on the reference appropriate vehicle speed value and tire temperature corresponding to the driving region identified as the driving region. This allows the appropriate vehicle speed value to be set based on the value that takes the driving region into consideration.

[0012] In one embodiment of the above-mentioned driving assistance system, the execution device performs a road surface state acquisition process, which acquires the road surface μ as the state of the road surface on which the vehicle is traveling, that is, the road surface state. In the appropriate value setting process, when the road surface μ is low, a value smaller than that when the road surface μ is high is set as the vehicle speed appropriate value.

[0013] If the μ value of the road surface on which the vehicle is traveling is low, the tires have difficulty gripping the road. In such cases, it is preferable to keep the vehicle speed low to ensure vehicle stability. In this regard, the above configuration allows the value corresponding to the road surface μ to be set as the appropriate vehicle speed value. This allows auxiliary processing to be executed to prevent the vehicle speed from being kept low when the tires have difficulty gripping the road surface.

[0014] In one aspect of the driving assistance system, the execution device sets the appropriate vehicle speed value based on weather information which is information related to weather in the appropriate value setting process.

[0015] When a vehicle is traveling on a road, the upper limit of the vehicle speed required to ensure stable driving conditions varies depending on the weather. For example, in rainy conditions, it is desirable to keep the vehicle speed lower than in calm conditions to ensure stable driving conditions. Furthermore, in conditions with high winds, it is desirable to keep the vehicle speed lower than in conditions with low winds to ensure stable driving conditions. In this regard, in the above configuration, a value that takes weather into account can be set as the appropriate vehicle speed value. This allows the driver to be assisted in responding to the weather.

[0016] In one embodiment of the driving assistance system, the vehicle includes a first driving mode and a second driving mode as driving modes selectable by the driver. The first driving mode is a driving mode that suppresses an increase in vehicle speed compared to the second driving mode. Furthermore, in the appropriate value setting process, the execution device sets, when the driver selects the first driving mode, a value smaller than that when the driver selects the second driving mode, as the appropriate vehicle speed value.

[0017] Drivers with high vehicle operating skills prefer to directly change the vehicle's driving conditions based on their own vehicle operation and therefore may not want assistance processing to intervene. On the other hand, when a driver with low vehicle operating skills operates the vehicle, they may prefer to keep the vehicle speed lower than when a driver with high vehicle operating skills operates the vehicle. With the above configuration, the driver can select a driving mode that corresponds to their vehicle operating skills. Furthermore, the value corresponding to the driver's selected driving mode can be set as the appropriate vehicle speed value. Thus, by executing assistance processing, the driver can be assisted according to the selected driving mode.

[0018] In one embodiment of the driving assistance system, the assistance process includes turn preparation control that requests the driver to decelerate the vehicle in preparation for the vehicle entering a curve. Furthermore, the execution device, during the assistance process, initiates the turn preparation control closer to the curve when the driver selects the first driving mode than when the driver selects the second driving mode.

[0019] When decelerating a vehicle, the greater the deceleration, the more likely the vehicle's driving stability is to deteriorate. Therefore, when a driver with low vehicle operating skills is operating the vehicle, it is preferable to suppress the increase in vehicle deceleration compared to when a driver with high vehicle operating skills is operating the vehicle.

[0020] Furthermore, when the vehicle is decelerating in preparation for entering a curve, the vehicle's deceleration tends to increase if the distance from the deceleration start point to the curve start point is short. On the other hand, if the distance is long, the vehicle's deceleration is less likely to increase. Specifically, when a driver with low vehicle operating skills is operating the vehicle, it is preferable to be able to notify the start of vehicle deceleration closer to the curve than when a driver with high vehicle operating skills is operating the vehicle.

[0021] The driver who selects the first driving mode is referred to as the first driver, and the driver who selects the second driving mode is referred to as the second driver. Drivers with higher vehicle operating skills are more likely to select the second mode than drivers with lower driving skills. Therefore, the first driver is more likely to have lower vehicle operating skills than the second driver. According to the above configuration, when the first driver operates the vehicle, turn preparation control begins closer to the curve than when the second driver operates the vehicle. This can prevent the vehicle from experiencing greater deceleration in the early stages of entering the curve when the first driver operates the vehicle, compared to when the second driver operates the vehicle.

[0022] In one embodiment of the driving assistance system, the assistance process includes deceleration assistance control for controlling the deceleration of the vehicle in preparation for the vehicle entering a curve. The actuator performs a deceleration request value setting process, which sets a deceleration request value, i.e., a required deceleration value, for the vehicle. In the deceleration assistance control, the vehicle is decelerated based on the deceleration request value. Furthermore, in the deceleration request value setting process, the actuator sets the deceleration request value to a smaller value than when the driver selects the second driving mode, if the driver selects the first driving mode.

[0023] When decelerating a vehicle, the greater the deceleration, the more likely the vehicle's driving stability will be reduced. In this regard, according to the above configuration, when the driver selects the first driving mode, a smaller deceleration request value is set than when the driver selects the second driving mode. Furthermore, the vehicle's deceleration is controlled based on this deceleration request value before the vehicle enters a curve. This prevents the vehicle from experiencing a greater deceleration before entering a curve when the first driver is operating the vehicle, compared to when the second driver is operating the vehicle.

[0024] In one embodiment of the driving assistance system, the execution device includes: a first execution device disposed outside the vehicle; and a second execution device disposed within the vehicle. The first and second execution devices are capable of transmitting and receiving information to and from each other. The second execution device executes a portion of the various processes, including the auxiliary process, while the first execution device executes the remaining processes.

[0025] In the above configuration, the first and second execution devices share the above processes, thereby reducing the load on each execution device compared to when a single execution device executes each process.

[0026] The vehicle driving assistance method for solving the above-mentioned problem is a method for assisting the driver in vehicle operation while the vehicle is driving. The driving assistance method includes the following processes: a temperature acquisition process for acquiring the temperature of the vehicle's tires, i.e., the tire temperature; an appropriate value setting process for setting an appropriate vehicle speed, i.e., an appropriate vehicle speed value, while the vehicle is driving; and an assistance process for performing at least one of a process of reporting the appropriate vehicle speed value set in the appropriate value setting process to the driver, and a process of decelerating the vehicle when the vehicle speed exceeds the appropriate vehicle speed value. The assistance process is executed by an actuator mounted on the vehicle. In addition, in the appropriate value setting process, a value that is smaller as the tire temperature acquired in the temperature acquisition process is lowered is derived as a candidate value for the appropriate vehicle speed value, and the appropriate vehicle speed value is set based on this candidate value.

[0027] By executing the above-mentioned processing, it is possible to obtain the same effects as those of the above-mentioned driving assistance system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like reference numerals designate like elements, wherein

[0029] Figure 1 This is a diagram schematically showing the configuration of a driving assistance system according to the first embodiment.

[0030] Figure 2 FIG. 1 is a diagram showing a track of a racing circuit managed by a server of the driving support system.

[0031] Figure 3 This is a schematic diagram showing a portion of the entire driving area.

[0032] Figure 4 This is a map indicating appropriate values ​​of the reference vehicle speed for each travel area.

[0033] Figure 5 This is a table showing the relationship between the driving mode, the mode correction coefficient, and the deceleration distance.

[0034] Figure 6 This is a flowchart illustrating a processing routine executed by the CPU of the server.

[0035] Figure 7 This is a flowchart illustrating a processing routine executed by the CPU of the vehicle control device of the driving assistance system.

[0036] Figure 8 This is a table showing the relationship between the driving mode, the mode correction coefficient, the deceleration distance, and the deceleration request value used in the driving assistance system of the second embodiment.

[0037] Figure 9 This is a flowchart illustrating a part of a processing routine executed by the CPU of the server of the driving assistance system.

[0038] Figure 10 This is a flowchart illustrating a processing routine executed by the CPU of the vehicle control device of the driving assistance system.

[0039] Figure 11 This is a flowchart illustrating a part of a processing routine executed by the CPU of the server of the driving assistance system according to the third embodiment.

[0040] Figure 12 This is a flowchart illustrating a processing routine executed by the CPU of the vehicle control device of the driving assistance system. DETAILED DESCRIPTION

[0041] (First embodiment)

[0042] The following, according to Figures 1 to 7 A first embodiment of a vehicle driving assistance system and a vehicle driving assistance method will be described.

[0043] <Overall Structure>

[0044] like Figure 1 As shown, the driving assistance system 10 includes a server control device 21 of a server 20 installed outside the vehicle and a vehicle control device 40 mounted on a vehicle 30. The server 20 can communicate with the vehicle 30. Figure 2 The vehicle control device 40 of the vehicle 30 running on the track 101 of the illustrated racetrack 100 transmits and receives various information. That is, when a plurality of vehicles 30 are running on the track 101, the server 20 transmits and receives various information to and from the vehicle control device 40 of each vehicle 30.

[0045] <Structure of Vehicle 30>

[0046] like Figure 1As shown, the vehicle 30 includes a vehicle-side communication device 31, a drive device 32, and a brake device 33 in addition to the vehicle control device 40. The drive device 32 adjusts the driving force of the vehicle 30. The brake device 33 adjusts the braking force of the vehicle 30.

[0047] The vehicle-side communication device 31 transmits information output from the vehicle control device 40 to the server 20 . In addition, the vehicle-side communication device 31 receives information transmitted from the server 20 and outputs the information to the vehicle control device 40 .

[0048] The vehicle control device 40 includes a CPU 41, a ROM 42, a storage device 43 serving as electrically rewritable nonvolatile memory, and an external circuit 44. The CPU 41, ROM 42, storage device 43, and external circuit 44 are capable of communicating via a local area network 45. The CPU 41 can exchange various information with the server control device 21 via the vehicle-side communication device 31. The ROM 42 stores control programs executed by the CPU 41. The storage device 43 stores various maps and tables. The external circuit 44 includes circuits for generating clock signals that regulate internal operations, power supply circuits, and reset circuits.

[0049] Vehicle 30 includes a mode operation unit 35 operated by the driver. Mode operation unit 35 is an operation unit for the driver to select a driving mode MD for vehicle 30. In this embodiment, multiple driving modes MD are provided. That is, the driver can select one of the multiple driving modes MD by operating mode operation unit 35.

[0050] For example, three driving modes are prepared as driving modes MD. Among the three driving modes, the first driving mode MD1 is a driving mode for beginners, the second driving mode MD2 is a driving mode for intermediates, and the third driving mode MD3 is a driving mode for advanceds. The first driving mode MD1 is a driving mode that suppresses the moving speed of the vehicle 30, that is, the vehicle speed, from being higher than the second driving mode MD2. In addition, the second driving mode MD2 is a driving mode that suppresses the vehicle speed from being higher than the third driving mode MD3. The beginner, intermediate, and advanced mentioned here are driving modes that make the vehicle 30 move at a higher speed. Figure 2 The level of vehicle operation when traveling on track 101 is shown.

[0051] The vehicle 30 is equipped with various sensors that output detection signals to the vehicle control device 40. Examples of these sensors include a vehicle speed sensor 51, a longitudinal acceleration sensor 52, a lateral acceleration sensor 53, a yaw rate sensor 54, and a steering angle sensor 55. The vehicle speed sensor 51 detects the vehicle speed V and outputs a detection signal corresponding to the detection result. The longitudinal acceleration sensor 52 detects the longitudinal acceleration Gx of the vehicle 30 and outputs a detection signal corresponding to the detection result. The lateral acceleration sensor 53 detects the lateral acceleration Gy of the vehicle 30 and outputs a detection signal corresponding to the detection result. The yaw rate sensor 54 detects the yaw rate Yr of the vehicle 30 and outputs a detection signal corresponding to the detection result. The steering angle sensor 55 detects the steering angle Str of the steering wheel of the vehicle 30 and outputs a detection signal corresponding to the detection result.

[0052] The vehicle 30 includes a GPS receiver 60. The GPS receiver 60 receives a GPS signal, which is a signal related to the current position coordinates CP of the vehicle 30, from a GPS satellite and outputs the GPS signal to the vehicle control device 40. The vehicle control device 40 obtains the current position coordinates CP of the vehicle 30 based on the GPS signal and transmits position information related to the position coordinates CP to the server 20 via the vehicle-side communication device 31.

[0053] In this embodiment, the vehicle control device 40 is in the process of Figure 2 When traveling on the track 101 shown, the driver's vehicle operation is assisted based on the appropriate vehicle speed value VL. For example, the vehicle control device 40 reports the appropriate vehicle speed value VL to the driver or decelerates the vehicle 30 when the vehicle speed V exceeds the appropriate vehicle speed value VL. The appropriate vehicle speed value VL refers to the appropriate vehicle speed for the vehicle 30 when traveling on the track 101. The appropriate vehicle speed value VL will be described in detail later, but the appropriate vehicle speed value VL can be changed as appropriate. Furthermore, vehicle operation includes at least steering, accelerator operation, and braking operation.

[0054] <Structure of Server 20>

[0055] like Figure 1 As shown, the server 20 includes a server-side communication device 28 in addition to the server control device 21. The server-side communication device 28 transmits information output from the server control device 21 to the vehicle 30. The server-side communication device 28 also receives information transmitted from the vehicle 30 and outputs it to the server control device 21.

[0056] The server control device 21 includes a CPU 22, a ROM 23, a storage device 24 serving as an electrically rewritable nonvolatile memory, and an external circuit 25. The CPU 22, ROM 23, storage device 24, and external circuit 25 can communicate via a local area network 26. The CPU 22 can exchange various information with the vehicle control device 40 via a server-side communication device 28. The ROM 23 stores a control program executed by the CPU 22. The storage device 24 stores various information necessary for setting the appropriate vehicle speed value VL. The external circuit 25 includes a circuit for generating a clock signal that regulates internal operations, a power supply circuit, a reset circuit, and the like.

[0057] The storage device 24 will Figure 2 The track 101 shown is divided into a plurality of driving areas AR for storage. Figure 3 FIG schematically shows a portion of the track 101. Figure 3 As shown, a plurality of running areas AR (1, 1), ..., (1, N), (2, 1), ..., (2, N), (3, 1), ..., (3, N), (4, 1), ..., (4, N) are stored in the storage device 24. Furthermore, "N" is the number of divisions of the track 101 in the traveling direction X1 of the vehicle 30. In the present embodiment, an integer equal to or greater than "5" is set as "N".

[0058] In this embodiment, multiple driving areas AR are set at the same position in the travel direction X1. For example, four driving areas AR(1,1), AR(2,1), AR(3,1), and AR(4,1) are located at the same position in the travel direction X1. Of these driving areas AR(1,1), AR(2,1), AR(3,1), and AR(4,1), driving area AR(1,1) is located at the outermost position Y1, and driving area AR(2,1) is located at the second outermost position Y1. Furthermore, driving area AR(3,1) is located at the third outermost position Y1, and driving area AR(4,1) is located at the innermost position Y2. Furthermore, driving area (1,2) is located closer to driving area AR(1,1) in the travel direction X1, and driving area (2,2) is located closer to driving area AR(2,1) in the travel direction X1.

[0059] In addition, if Figure 4 As shown, the storage device 24 has a map MP storing a reference vehicle speed appropriate value VLb, which is a reference of the vehicle speed appropriate value VL, for each of the plurality of travel areas AR. Figure 4As shown, "110 km / h" is set as the appropriate reference vehicle speed value VLb for the travel area AR(1,1). "110 km / h" is set as the appropriate reference vehicle speed value VLb for the travel area AR(1,2). "100 km / h" is set as the appropriate reference vehicle speed value VLb for the travel area AR(1,3). "130 km / h" is set as the appropriate reference vehicle speed value VLb for the travel area AR(2,1). "130 km / h" is set as the appropriate reference vehicle speed value VLb for the travel area AR(3,1).

[0060] In addition, if Figure 5 As shown, the storage device 24 includes a table TL for setting a mode correction coefficient Hm and a deceleration distance Lg corresponding to the driving mode MD. The mode correction coefficient Hm is a correction coefficient used when deriving the appropriate vehicle speed value VL. The mode correction coefficient Hm is used to derive the value corresponding to the driving mode MD selected by the driver as the appropriate vehicle speed value VL. The deceleration distance Lg is a parameter used when decelerating the vehicle 30 just before a curve on the auxiliary track 101. In other words, when the vehicle 30 approaches the curve and the distance from the vehicle 30 to the start position of the curve becomes less than the deceleration distance Lg, it is preferable to decelerate the vehicle 30. In this embodiment, the section from the start position of the curve to a position closer to the start position by the deceleration distance Lg is also referred to as a "deceleration section."

[0061] like Figure 5 As shown, a first mode correction coefficient Hm1 is set as the mode correction coefficient Hm for the first driving mode MD1. For example, the first mode correction coefficient Hm1 can be set to "1." A first deceleration distance Lg1 is set as the deceleration distance Lg for the first driving mode MD1.

[0062] A second mode correction coefficient Hm2 greater than the first mode correction coefficient Hm1 is set as the mode correction coefficient Hm for the second driving mode MD2. A second deceleration distance Lg2 is set as the deceleration distance Lg for the second driving mode MD2. The second deceleration distance Lg2 is shorter than the first deceleration distance Lg1.

[0063] A third mode correction coefficient Hm3, which is larger than the second mode correction coefficient Hm2, is set as the mode correction coefficient Hm for the third driving mode MD3. A third deceleration distance Lg3 is set as the deceleration distance Lg for the third driving mode MD3. The third deceleration distance Lg3 is shorter than the second deceleration distance Lg2.

[0064] like Figure 1As shown, server 20 acquires weather information related to the weather at circuit 100. Consequently, server control device 21 can understand the weather at circuit 100. For example, server control device 21 can understand whether it is raining. Furthermore, if it is raining, server control device 21 can understand the amount of precipitation. Furthermore, server control device 21 can understand the wind direction and wind volume at circuit 100.

[0065] <Flow of Processing for Assisting Driver's Vehicle Operation When Driving Vehicle 30 on Track 101>

[0066] When the vehicle 30 is traveling on the track 101, the vehicle control device 40 sequentially transmits position information related to the current position coordinates CP of the vehicle 30 to the server 20 via the vehicle-side communication device 31. The server control device 21 of the server 20 then sets an appropriate vehicle speed value VLa based on the position coordinates CP of the vehicle 30 and transmits the appropriate vehicle speed value VLa to the vehicle 30.

[0067] exist Figure 6 2 shows a processing routine executed by the CPU 22 of the server control device 21. The CPU 22 repeatedly executes this processing routine.

[0068] In this processing routine, at the beginning of step S11, the CPU 22 determines whether various information has been received from the vehicle 30. This information is necessary for deriving the appropriate vehicle speed value VL and the deceleration distance Lg. For example, the CPU 22 determines whether the current position coordinates CP of the vehicle 30 and the driving mode MD selected by the driver have been received. If the various information has not been received (S11: No), the CPU 22 repeats the determination in step S11 until the information has been received. On the other hand, if the various information has been received (S11: Yes), the CPU 22 transfers the process to step S13.

[0069] In step S13, the CPU 22 identifies the driving area ARD, which is the driving area in which the vehicle 30 is currently traveling, based on the acquired position coordinates CP, from among all driving areas AR. For example, the CPU 22 selects the driving area AR that includes the acquired position coordinates CP as the driving area ARD. Next, in step S15, the CPU 22 obtains the appropriate reference vehicle speed value VLb based on the driving area ARD. Specifically, the CPU 22 obtains the appropriate reference vehicle speed value VLb for the driving area AR identified within the driving area ARD from the map MP in the storage device 24.

[0070] In the next step S17, the CPU 22 Figure 5The table TL shown in the figure acquires the mode correction coefficient Hm corresponding to the driving mode MD selected by the driver. Then, in step S19, the CPU 22 derives the product of the appropriate reference vehicle speed value VLb and the mode correction coefficient Hm as the corrected appropriate reference vehicle speed value VLb1. The corrected appropriate reference vehicle speed value VLb1 when the driver selects the first driving mode MD1 is smaller than the corrected appropriate reference vehicle speed value VLb1 when the driver selects the second driving mode MD2. The corrected appropriate reference vehicle speed value VLb1 when the driver selects the second driving mode MD2 is smaller than the corrected appropriate reference vehicle speed value VLb1 when the driver selects the third driving mode MD3.

[0071] Next, in step S21, CPU 22 obtains the temperature of the tires of vehicle 30, namely, tire temperature TMPty. For example, CPU 22 obtains an estimated value of the tire temperature based on the number of times vehicle 30 has circumnavigated track 101 as tire temperature TMPty. The longer the distance vehicle 30 has traveled after starting on track 101, the higher the tire temperature can be estimated to be. As the number of times vehicle 30 has circumnavigated track 101 increases, the distance traveled by vehicle 30 increases. Therefore, CPU 22 obtains a larger value as tire temperature TMPty as the number of circumnavigations increases. Thus, the longer the distance vehicle 30 has traveled after starting on track 101, the higher the temperature can be obtained as tire temperature TMPty. Furthermore, when the number of circumnavigations is "1," for example, CPU 22 may obtain the outside air temperature or a temperature corresponding to the outside air temperature as tire temperature TMPty.

[0072] In the following step S23, CPU 22 sets a tire temperature correction coefficient Htmp based on tire temperature TMPty. Tire temperature correction coefficient Htmp is used to set a value corresponding to tire temperature TMPty as appropriate vehicle speed value VL. For example, CPU 22 sets tire temperature correction coefficient Htmp to a smaller value as tire temperature TMPty decreases. Then, in step S25, CPU 22 derives the product of the corrected appropriate reference vehicle speed value VLb1 and tire temperature correction coefficient Htmp as the first candidate vehicle speed value VLa1. Thus, a smaller value is set as tire temperature TMPty decreases as first candidate vehicle speed value VLa1.

[0073] Next, in step S27, CPU 22 sets a precipitation correction coefficient Hpr based on the received weather information. Precipitation correction coefficient Hpr is used to set the appropriate vehicle speed value VL to a value corresponding to the weather at circuit 100. Specifically, precipitation correction coefficient Hpr is used to set the appropriate vehicle speed value VL to a value corresponding to the amount of precipitation at circuit 100. For example, if it is raining, CPU 22 sets precipitation correction coefficient Hpr to a smaller value than if it is not raining. Alternatively, if it is raining, CPU 22 sets precipitation correction coefficient Hpr to a smaller value as the amount of precipitation increases. Then, in step S29, CPU 22 derives the product of the corrected appropriate reference vehicle speed value VLb1 and precipitation correction coefficient Hpr as the second candidate vehicle speed value VLa2. Consequently, if it is raining at circuit 100, a smaller value is set as the second candidate vehicle speed value VLa2 than if it is not raining. Furthermore, when it rains at the racetrack 100 , a value that decreases as the amount of precipitation increases is set as the second vehicle speed candidate value VLa2 .

[0074] In the following step S31, CPU 22 sets the wind volume correction coefficient Hws based on the received weather information. Wind volume correction coefficient Hws is used to set the appropriate vehicle speed value VL to a value corresponding to the weather at racetrack 100. Specifically, wind volume correction coefficient Hws is used to set the appropriate vehicle speed value VL to a value corresponding to the wind volume at racetrack 100. For example, CPU 22 sets wind volume correction coefficient Hws to a value that decreases as the wind volume increases. Then, in step S33, CPU 22 derives the product of the corrected reference appropriate vehicle speed value VLb1 and the wind volume correction coefficient Hws as the third candidate vehicle speed value VLa3. Thus, the third candidate vehicle speed value VLa3 is set to a value that decreases as the wind volume increases.

[0075] Next, in step S35, the CPU 22 derives the appropriate vehicle speed value VLa based on the first, second, and third candidate vehicle speed values ​​VLa1, VLa2, and VLa3. For example, the CPU 22 derives the minimum value among the first, second, and third candidate vehicle speed values ​​VLa1, VLa2, and VLa3 as the appropriate vehicle speed value VLa. For example, if the first candidate vehicle speed value VLa1 is the minimum among the three candidate vehicle speed values ​​VLa1, VLa2, and VLa3, the appropriate vehicle speed value VLa is set to a value that decreases as the tire temperature TMPty decreases. Alternatively, if the second candidate vehicle speed value VLa2 is the minimum among the three candidate vehicle speed values ​​VLa1, VLa2, and VLa3, the appropriate vehicle speed value VLa is set to a value that decreases as the amount of precipitation increases. For example, when the third vehicle speed candidate value VLa3 is the smallest among the three vehicle speed candidate values ​​VLa1 , VLa2 , and VLa3 , a value that decreases as the air volume increases is set as the appropriate vehicle speed value VLa.

[0076] In the next step S37, the CPU 22 Figure 5 The table TL shown acquires the deceleration distance Lg corresponding to the driving mode MD selected by the driver. Then, in step S39, the CPU 22 determines whether the vehicle 30 has entered a deceleration section based on the driving area ARD and the deceleration distance Lg. If the vehicle 30 has entered a deceleration section, it is preferable to decelerate the vehicle 30 in preparation for entering the curve. As described above, the section from a position closer to the start position of the curve by the deceleration distance Lg to the start position is set as the deceleration section. The deceleration distance Lg is the length corresponding to the driving mode MD selected by the driver. Therefore, the dimension of the deceleration section in the travel direction X1 varies depending on the driving mode MD selected by the driver. Furthermore, if the driving area ARD is included in the deceleration section, the vehicle 30 is deemed to have entered the deceleration section. On the other hand, if the driving area ARD is not included in the deceleration section, the vehicle 30 is not deemed to have entered the deceleration section.

[0077] If it is determined that the vehicle 30 has entered the deceleration zone (S39: YES), the CPU 22 proceeds to step S41. In step S41, the CPU 22 turns on the deceleration flag FLGg. Then, the CPU 22 proceeds to step S45.

[0078] On the other hand, if it is determined in step S39 that the vehicle 30 has not entered the deceleration zone (S39: NO), the CPU 22 shifts the process to step S43. In step S43, the CPU 22 turns off the deceleration flag FLGg. Then, the CPU 22 shifts the process to step S45.

[0079] In step S45, the CPU 22 executes a transmission process of transmitting the appropriate vehicle speed value VLa and the deceleration flag FLGg from the server-side communication device 28 to the vehicle 30. Then, the CPU 22 temporarily ends this processing routine.

[0080] The CPU 41 of the vehicle control device 40 receives the appropriate vehicle speed value VLa from the server 20 and determines an appropriate vehicle speed value VL. The CPU 41 then assists the driver in vehicle operation based on the appropriate vehicle speed value VL and the deceleration flag FLGg.

[0081] exist Figure 7 FIGURE 4 illustrates a processing routine executed by the CPU 41 of the vehicle control device 40. The CPU 41 repeatedly executes this processing routine. Initially, in step S51, the CPU 41 determines whether the appropriate vehicle speed value VLa and the deceleration flag FLGg have been received. If the appropriate vehicle speed value VLa and the deceleration flag FLGg have not been received (S51: NO), the CPU 41 repeats the determination in step S51 until they have been received. On the other hand, if the appropriate vehicle speed value VLa and the deceleration flag FLGg have been received (S51: YES), the CPU 41 proceeds to step S53.

[0082] In step S53, the CPU 41 obtains the road surface condition of the driving area ARD. In this embodiment, the CPU 41 obtains an estimated value of road surface μ as the road surface condition. For example, when driving force is input to the wheels of the vehicle 30, the CPU 41 can derive the estimated value of road surface μ based on the driving force and the slip of the wheels.

[0083] Then, in step S55, the CPU 41 derives the appropriate vehicle speed value VL based on the appropriate vehicle speed value VLa and the road surface condition. For example, the CPU 41 determines whether the estimated value of road surface μ derived as the road surface condition is greater than the μ determination value. The μ determination value is set as a criterion for determining whether the road surface is a low μ road. If the estimated value of road surface μ is less than the μ determination value, the road surface is considered to be a low μ road. If the estimated value of road surface μ is greater than the μ determination value, the road surface is not considered to be a low μ road. If the estimated value of road surface μ is less than the μ determination value, the CPU 41 sets a positive value as the adjustment value H3. On the other hand, if the estimated value of road surface μ is greater than the μ determination value, the CPU 41 sets "0" as the adjustment value H3. Then, the CPU 41 derives the value obtained by subtracting the adjustment value H3 from the appropriate vehicle speed value VLa as the appropriate vehicle speed value VL.

[0084] When the appropriate vehicle speed value VL is derived in this manner, the CPU 41 executes an assist process for assisting the vehicle operation of the driver of the vehicle 30 traveling on the track 101. In the present embodiment, the assist process includes speed assist control and turn preparation control.

[0085] That is, in step S57, the CPU 41 implements speed assist control. In this embodiment, the CPU 41 reports the appropriate vehicle speed value VL to the driver. In addition, when the vehicle speed V exceeds the appropriate vehicle speed value VL, the CPU 41 controls at least one of the drive device 32 and the brake device 33 to decelerate the vehicle 30.

[0086] In the next step S59, the CPU 41 determines whether the deceleration flag FLGg received from the server 20 is set to ON. If the deceleration flag FLGg is set to ON (S59: YES), the CPU 41 transfers the process to step S61. On the other hand, if the deceleration flag FLGg is set to OFF (S59: NO), the CPU 41 temporarily ends this processing routine.

[0087] In step S61, the CPU 41 implements turn preparation control to request the driver to decelerate the vehicle 30. For example, the CPU 41 requests the driver to perform a braking operation. Specifically, if the CPU 41 determines that the vehicle 30 has entered a deceleration zone, it requests the driver to perform a vehicle operation to decelerate the vehicle 30. The CPU 41 then temporarily terminates this processing routine.

[0088] <Correspondence>

[0089] The correspondence between the matters in this embodiment and the matters described in the above-mentioned "means for solving the problem" column is as follows.

[0090] Step S21 corresponds to the "temperature acquisition process" for acquiring the tire temperature TMPty, which is the temperature of the tires of the vehicle 30. Steps S19, S25, S29, S33, S35, and S55 correspond to the "appropriate value setting process" for setting the appropriate vehicle speed value VL. In this embodiment, multiple candidate vehicle speed values ​​are derived, and the appropriate vehicle speed value VL is set based on each candidate vehicle speed value. In particular, step S25 corresponds to the process for deriving a first candidate vehicle speed value VLa1, which is smaller as the tire temperature TMPty decreases. Steps S29 and S33 correspond to the process for deriving candidate vehicle speed values ​​VLa2 and VLa3 based on weather information. Step S19 corresponds to the process for setting the appropriate vehicle speed value VL based on the driving mode MD selected by the driver. Step S55 corresponds to the process for setting the appropriate vehicle speed value VL based on the road surface conditions.

[0091] Steps S57 and S61 correspond to "assistance processing." In particular, step S57 corresponds to "speed assist control," which performs at least one of reporting the appropriate vehicle speed value VL to the driver and decelerating the vehicle when the vehicle speed V exceeds the appropriate vehicle speed value VL. Furthermore, step S61 corresponds to "turn preparation control," which requests the driver to decelerate the vehicle 30 in preparation for the vehicle 30 entering a curve.

[0092] Step S13 corresponds to a “determination process” of determining the traveling area ARD from the plurality of traveling areas AR. Step S53 corresponds to a “road surface state acquisition process” of acquiring a road surface μ as the road surface state.

[0093] The storage device 24 of the server control device 21 corresponds to a "storage device" that stores the information obtained by dividing the road on which the vehicle 30 is traveling into a plurality of travel areas AR. The CPU 22 of the server control device 21 and the CPU 41 of the vehicle control device 40 correspond to "execution devices" that execute the aforementioned processes. Furthermore, the CPU 41 of the vehicle control device 40 corresponds to a "second execution device" that executes a portion of the aforementioned processes, including auxiliary processes, while the CPU 22 of the server control device 21 corresponds to a "first execution device" that executes the remaining processes.

[0094] Each of the vehicle speed candidate values ​​VLa1 to VLa3 corresponds to a “candidate value of the appropriate vehicle speed value.” Among the vehicle speed candidate values ​​VLa1 to VLa3 , the first vehicle speed candidate value VLa1 corresponds to a “candidate value” derived to be smaller as the tire temperature TMPty decreases.

[0095] <Functions and Effects of First Embodiment>

[0096] (1-1) In vehicle 30 Figure 2 In the case of running on track 101 shown, the tire temperature of vehicle 30 is relatively low at the start of running. The lower the tire temperature, the weaker the tire grip. The weaker the tire grip, the more likely the vehicle's running stability will deteriorate. Therefore, when the tire temperature is low, it is preferable to keep vehicle speed V lower than when the tire temperature is high.

[0097] In this embodiment, a value that decreases as the tire temperature TMPty decreases is derived as the first candidate vehicle speed value VLa1, and the appropriate vehicle speed value VL is set based on this first candidate vehicle speed value VLa1. Therefore, the appropriate vehicle speed value VL can be set to a value that decreases as the tire temperature TMPty decreases. Specifically, if the vehicle 30 travels on the same track 101 and the tire temperature TMPty varies, the tire grip may vary, and therefore a different value can be set as the appropriate vehicle speed value VL.

[0098] Therefore, according to this embodiment, the vehicle speed appropriateness value VL can be set to a value that takes into account the state of the vehicle 30, specifically, the grip of the tires of the vehicle 30. Therefore, the driver's vehicle operation can be assisted by taking into account the grip of the tires at that time.

[0099] (1-2) In this embodiment, tire temperature TMPty is acquired based on the number of times vehicle 30 has circumnavigated track 101, which is related to the travel distance of vehicle 30. Thus, even without installing a tire temperature sensor on vehicle 30, a value corresponding to tire temperature TMPty can be set as appropriate vehicle speed value VL.

[0100] (1-3) When the vehicle 30 is traveling on a track 101 with which the driver is unfamiliar, it is preferable to keep the vehicle speed V low to ensure the safety of the vehicle 30. On the other hand, as the vehicle 30 repeatedly travels on the same track 101, the driver's familiarity with the vehicle operations for traveling on the track 101 increases. Therefore, when the driver's familiarity is high, the vehicle speed V does not need to be kept too low compared to when the driver's familiarity is low.

[0101] In this embodiment, the appropriate vehicle speed value VL can be set to a larger value as the number of times the vehicle 30 circumnavigates the track 101 increases. In other words, the appropriate vehicle speed value VL can be set to a larger value as the driver's familiarity with vehicle operation for traveling the track 101 with the vehicle 30 increases. Therefore, in this embodiment, the appropriate vehicle speed value VL can be set to a value corresponding to the driver's familiarity. Furthermore, the driver's familiarity can be taken into account to assist the driver in vehicle operation.

[0102] In this case, the number of times vehicle 30 circles the track 101 corresponds to an indicator of the driver's familiarity with vehicle operation for traveling on the road on which vehicle 30 is traveling. In this case, the process of measuring the number of times vehicle 30 circles the track 101 corresponds to "indicator acquisition processing" for acquiring an indicator of familiarity.

[0103] (1-4) When the vehicle 30 is traveling on the track 101, the driving area ARD is determined from a plurality of driving areas AR defined by dividing the track 101. The appropriate vehicle speed value VL is then set based on the reference appropriate vehicle speed value VLb corresponding to the driving area ARD. Thus, the appropriate vehicle speed value VL can be set to a value corresponding to the area in which the vehicle 30 is traveling. Furthermore, the driving area ARD can be taken into consideration to assist the driver in vehicle operation.

[0104] (1-5) When the vehicle 30 is traveling on a road with a low μ value, the vehicle's driving condition tends to become disturbed. In other words, to ensure the stability of the vehicle's driving condition, it is preferable to keep the vehicle speed V low when the road surface μ is low. Therefore, in this embodiment, when the road surface μ is low, a smaller value can be set as the appropriate vehicle speed value VL than when the road surface μ is not low. Therefore, the driver's vehicle operation can be assisted by also taking the road surface μ into consideration.

[0105] (1-6) If the weather at racetrack 100 also changes, the appropriate speed for driving vehicle 30 on track 101 can be changed while ensuring the stability of the vehicle's driving conditions. For example, the greater the amount of precipitation, the worse the driver's visibility, making it more difficult to drive vehicle 30. Furthermore, for example, the greater the wind speed, the greater the external force acting on vehicle 30, and the more likely the vehicle's driving conditions will deteriorate.

[0106] In this regard, in this embodiment, a value corresponding to the rain determination or the wind speed can be set as the appropriate vehicle speed value VL. In other words, a value that also takes the weather into consideration can be set as the appropriate vehicle speed value VL. This allows the driver's vehicle operation to be assisted while also taking the weather into consideration.

[0107] (1-7) In the present embodiment, a value corresponding to the driving mode MD selected by the driver is set as the appropriate vehicle speed value VL. That is, by executing the assistance process, the driver can be assisted according to the driving mode MD selected by the driver.

[0108] For example, suppose a driver who lacks confidence in driving the vehicle on track 101 selects the first driving mode MD1. In this case, a smaller value is set as the appropriate vehicle speed value VL than when driving modes MD2 or MD3 other than the first driving mode MD1 are selected. If the driver operates the vehicle in this state, the appropriate vehicle speed value VL is reported to the driver. Therefore, the driver can operate the vehicle according to the reported appropriate vehicle speed value VL, allowing vehicle 30 to safely travel on track 101.

[0109] For example, assume that a driver, who has a certain degree of confidence in driving the vehicle on track 101, selects the second driving mode MD2. In this case, a larger value is set as the appropriate vehicle speed value VL than when the first driving mode MD1 is selected. If the driver operates the vehicle in this state, the appropriate vehicle speed value VL is reported to the driver. In this case, assistance processing is less likely to intervene than when the first driving mode MD1 is selected. Therefore, the driver operates the vehicle according to the reported appropriate vehicle speed value VL, allowing the driver to enjoy driving the vehicle 30 on track 101.

[0110] (1-8) When decelerating the vehicle 30, the greater the deceleration, the more likely the driving stability of the vehicle 30 will deteriorate. Therefore, when the driver selects the first driving mode MD1, which is a driving mode for beginners, it is preferable to assist the driver's vehicle operation so that the deceleration of the vehicle 30 does not increase, compared to when other driving modes are selected.

[0111] Furthermore, when the vehicle 30 is decelerated in preparation for entering a curve, if the distance from the deceleration start point to the curve start point is short, the deceleration of the vehicle 30 tends to increase. On the other hand, if the distance is long, the deceleration of the vehicle 30 is less likely to increase. Specifically, when a driver with low vehicle operating skills is operating the vehicle, it is preferable to be able to notify the start of deceleration of the vehicle 30 closer to the curve than when a driver with high vehicle operating skills is operating the vehicle.

[0112] In this embodiment, when it is determined that vehicle 30 has entered a deceleration zone, the driver is requested to perform a vehicle operation to decelerate vehicle 30 through turn preparation control. When the driver selects the first driving mode MD1, the deceleration zone's dimension in the travel direction X1 is larger than when the driver selects the other driving modes MD2 or MD3. Therefore, when the driver selects the first driving mode MD1, turn preparation control is initiated closer to the curve than when the driver selects the other driving modes MD2 or MD3. Consequently, when the driver selects the first driving mode MD1, vehicle 30 can enter a curve at a sufficiently reduced speed, without increasing the deceleration of vehicle 30, compared to when the driver selects the other driving modes MD2 or MD3.

[0113] That is, in the present embodiment, when the vehicle 30 is traveling just before a curve, the driver can be assisted according to the driving mode selected by the driver.

[0114] (1-9) In this embodiment, the appropriate vehicle speed value VL is set by the cooperation of the server control device 21 and the vehicle control device 40. Therefore, the control load on each of the control devices 21 and 40 can be reduced compared to when a single control device executes each process for setting the appropriate vehicle speed value VL.

[0115] (Second embodiment)

[0116] according to Figures 8 to 10 A second embodiment of a vehicle driving assistance system and a vehicle driving assistance method will be described. In the following description, the differences from the first embodiment will be mainly described, and the same or corresponding components as those in the first embodiment will be denoted by the same reference numerals and repeated description will be omitted.

[0117] <Structure of Server 20>

[0118] The storage device 24 of the server control device 21 has Figure 8 As shown in Table TL1. Figure 8 As shown, table TL1 is used to set the mode correction coefficient Hm, deceleration distance Lg, and deceleration request value DecR according to driving mode MD. In this embodiment, deceleration assist control is implemented to assist in decelerating vehicle 30 in preparation for entering a curve. Deceleration request value DecR is the target value for the deceleration of vehicle 30 during deceleration assist control.

[0119] like Figure 8 As shown, the deceleration request value DecR for the first driving mode MD1 is the first deceleration request value Dec1. The deceleration request value DecR for the second driving mode MD2 is the second deceleration request value Dec2. The deceleration request value DecR for the third driving mode MD3 is the third deceleration request value Dec3. When the vehicle 30 decelerates, the greater the deceleration, the more likely the vehicle's driving stability will deteriorate. Therefore, the first deceleration request value Dec1 is smaller than the second deceleration request value Dec2 and the third deceleration request value Dec3. The third deceleration request value Dec3 is larger than the first deceleration request value Dec1 and the second deceleration request value Dec2.

[0120] <Flow of Processing for Assisting Driver's Vehicle Operation When Driving Vehicle 30 on Track 101>

[0121] Figure 9 The figure shows a part of the processing routine executed by the CPU 22 of the server control device 21. The CPU 22 repeatedly executes this processing routine.

[0122] In this processing routine, the CPU 22 executes Figure 6 The same process is performed as in steps S11 to S35 shown in FIG. When the CPU 22 executes the process of step S35, the process is transferred to step S37. In step S37, the CPU 22 obtains the deceleration distance Lg corresponding to the driving mode MD selected by the driver. Then, in step S38, the CPU 22 obtains the deceleration distance Lg corresponding to the driving mode MD selected by the driver. Figure 8 The table TL1 shown acquires the deceleration request value DecR corresponding to the driving mode MD selected by the driver.

[0123] In the next step S39, the CPU 22 determines whether the vehicle 30 has entered a deceleration zone based on the driving area ARD and the deceleration distance Lg. If the vehicle 30 has entered a deceleration zone (S39: Yes), the CPU 22 transfers the process to step S41. In step S41, the CPU 22 sets the deceleration flag FLGg to ON. The CPU 22 then transfers the process to step S45.

[0124] On the other hand, in step S39, if it is determined that the vehicle 30 has not entered the deceleration zone (No), the CPU 22 moves the process to step S43. In step S43, the CPU 22 sets the deceleration flag FLGg to OFF. Then, the CPU 22 moves the process to step S45.

[0125] In step S45, the CPU 22 executes a transmission process for transmitting the appropriate vehicle speed value VLa, the deceleration request value DecR, and the deceleration flag FLGg from the server-side communication device 28 to the vehicle 30. Then, the CPU 22 temporarily ends this processing routine.

[0126] exist Figure 10 2 shows a processing routine executed by the CPU 41 of the vehicle control device 40. The CPU 41 repeatedly executes this processing routine.

[0127] In this processing routine, at the beginning of step S71, the CPU 41 determines whether the appropriate vehicle speed value VLa, the requested deceleration value DecR, and the deceleration flag FLGg have been received. If the appropriate vehicle speed value VLa, the requested deceleration value DecR, and the deceleration flag FLGg have not been received (S71: No), the CPU 41 repeats the determination of step S71 until they have been received. On the other hand, if the appropriate vehicle speed value VLa, the requested deceleration value DecR, and the deceleration flag FLGg have been received (S71: Yes), the CPU 41 proceeds to step S73.

[0128] In step S73, the CPU 41 obtains an estimated value of the road surface μ as the road surface state of the traveling area ARD, similarly to step S53. Then, in step S75, the CPU 41 derives an appropriate vehicle speed value VL, similarly to step S55.

[0129] In the next step S77, the CPU 41 determines whether the deceleration flag FLGg received from the server 20 is set to OFF. If the deceleration flag FLGg is set to OFF (S77: YES), the CPU 41 transfers the process to step S79. In step S79, the CPU 41 performs speed assist control in the same manner as in step S57. The CPU 41 then temporarily terminates this processing routine.

[0130] On the other hand, if the deceleration flag FLGg is set to ON in step S77 (No), the CPU 41 transfers the process to step S81. In step S81, the CPU 41 implements deceleration assist control. For example, the CPU 41 drives the brake device 33 and the drive device 32 in a manner such that the deceleration of the vehicle 30 is not less than the deceleration request value DecR. In this case, if the deceleration of the vehicle 30 is greater than the deceleration request value DecR due to the driver's braking operation, the CPU 41 may not instruct the brake device 33 and the drive device 32 to drive the vehicle 30 to decelerate. The CPU 41 then temporarily ends this processing routine.

[0131] In this embodiment, if the vehicle 30 is not determined to have entered a deceleration zone, speed assist control is implemented as an assist process. That is, the driver is assisted based on the appropriate vehicle speed value VL. On the other hand, if the vehicle 30 is determined to have entered a deceleration zone, deceleration assist control is implemented as an assist process. That is, the driver is assisted based not on the appropriate vehicle speed value VL but on the deceleration request value DecR.

[0132] <Correspondence>

[0133] The correspondence between the matters in this embodiment and the matters described in the above-mentioned "means for solving the problem" column is as follows.

[0134] Step S21 corresponds to "temperature acquisition processing." Steps S19, S25, S29, S33, S35, and S75 correspond to "appropriate value setting processing." In this embodiment, multiple candidate vehicle speed values ​​are derived, and the appropriate vehicle speed value VL is set based on each candidate vehicle speed value. In particular, step S25 corresponds to processing for deriving a first candidate vehicle speed value VLa1, which is a smaller value as the tire temperature TMPty decreases. Steps S29 and S33 correspond to processing for deriving candidate vehicle speed values ​​VLa2 and VLa3 based on weather information. Step S19 corresponds to processing for setting the appropriate vehicle speed value VL based on the driving mode MD selected by the driver. Step S75 corresponds to processing for setting the appropriate vehicle speed value VL based on the road surface conditions.

[0135] Steps S77 to S81 correspond to "assistance processing." In particular, step S79 corresponds to "speed assist control," which performs at least one of reporting the appropriate vehicle speed value VL to the driver and decelerating the vehicle when the vehicle speed V exceeds the appropriate vehicle speed value VL. Furthermore, step S81 corresponds to "deceleration assist control," which controls the deceleration of the vehicle 30 in preparation for entering a curve. Step S13 corresponds to "determination processing." Step S73 corresponds to "road surface condition acquisition processing." Step S38 corresponds to "deceleration request value setting processing," which sets the deceleration request value DecR.

[0136] The storage device 24 of the server control device 21 corresponds to a "storage device" that stores the information obtained by dividing the road traveled by the vehicle 30 into a plurality of travel areas AR. The CPU 22 of the server control device 21 and the CPU 41 of the vehicle control device 40 correspond to "execution devices" that execute the aforementioned processes. Furthermore, the CPU 41 of the vehicle control device 40 corresponds to a "second execution device," and the CPU 22 of the server control device 21 corresponds to a "first execution device."

[0137] Each of the vehicle speed candidate values ​​VLa1 to VLa3 corresponds to a “candidate value of the appropriate vehicle speed value.” Among the vehicle speed candidate values ​​VLa1 to VLa3 , the first vehicle speed candidate value VLa1 corresponds to a “candidate value” derived to be smaller as the tire temperature TMPty decreases.

[0138] <Functions and Effects of Second Embodiment>

[0139] In this embodiment, in addition to the effects equivalent to the effects (1-1) to (1-7) and (1-9) in the above-mentioned first embodiment, the following effects can be obtained.

[0140] (2-1) When vehicle 30 approaches a curve, deceleration assist control is performed in preparation for vehicle 30 entering the curve. Thus, deceleration of vehicle 30 is controlled based on required deceleration value DecR. As a result, regardless of whether the driver performs a vehicle operation to decelerate vehicle 30, it is possible to prevent vehicle 30 from entering the curve after sufficiently reducing vehicle speed V.

[0141] (2-2) When decelerating the vehicle 30, the greater the deceleration, the more likely the vehicle's driving stability will deteriorate. Regarding this point, in the present embodiment, when the driver selects the first driving mode MD1, a smaller value is set as the deceleration request value DecR than when the driver selects the other driving mode MD2.

[0142] Here, a driver with low vehicle operating skills is more likely to select the first driving mode MD1 than the second driving mode MD2 and the third driving mode MD3.

[0143] Furthermore, when the driver selects the first driving mode MD1, the deceleration of the vehicle 30 can be suppressed from increasing significantly in the period before the vehicle 30 enters a curve, compared to when the other driving modes MD2 and MD3 are selected. As a result, the driver can perform steering operations with peace of mind while the vehicle 30 is decelerating in preparation for entering the curve.

[0144] (Third embodiment)

[0145] according to Figure 11and Figure 12 A third embodiment of a vehicle driving assistance system and a vehicle driving assistance method will be described. The following description will focus on the differences from the first embodiment, and components identical or corresponding to those in the aforementioned embodiments will be denoted by the same reference numerals, and duplicate description will be omitted.

[0146] <Flow of Processing for Assisting Driver's Vehicle Operation When Driving Vehicle 30 on Track 101>

[0147] Figure 11 The figure shows a part of the processing routine executed by the CPU 22 of the server control device 21. The CPU 22 repeatedly executes this processing routine.

[0148] In this processing routine, if the CPU 22 completes receiving various information from the vehicle 30 (YES) in step S11, it determines the driving area ARD in step S13. Next, the CPU 22 obtains the appropriate reference vehicle speed value VLb in step S15 and the mode correction coefficient Hm in step S17. Furthermore, the CPU 22 obtains the tire temperature TMPty in step S21 and sets the tire temperature correction coefficient Htmp in step S23. Furthermore, the CPU 22 sets the precipitation correction coefficient Hpr in step S27 and the wind volume correction coefficient Hws in step S31.

[0149] Furthermore, the CPU 22 selects the deceleration distance Lg in step S37 and determines in step S39 whether the vehicle 30 has entered a deceleration zone. If the CPU 22 determines that the vehicle 30 has entered a deceleration zone (S39: Yes), the CPU 22 sets the deceleration flag FLGg to ON in step S41. On the other hand, if the CPU 22 does not determine that the vehicle 30 has entered a deceleration zone (S39: No), the CPU 22 sets the deceleration flag FLGg to OFF in step S43.

[0150] Then, in step S45, the CPU 22 transmits the appropriate reference vehicle speed value VLb, the correction coefficients Hm, Htmp, Hpr, Hws, and the deceleration flag FLGg from the server-side communication device 28 to the vehicle 30. The CPU 22 then temporarily terminates this processing routine.

[0151] Figure 12 The figure shows a processing routine executed by the CPU 41 of the vehicle control device 40. The CPU 41 repeatedly executes this processing routine.

[0152] In this processing routine, at the beginning of step S91, the CPU 41 determines whether the appropriate reference vehicle speed value VLb, the correction coefficients Hm, Htmp, Hpr, Hws, and the deceleration flag FLGg have been received. If at least one of the appropriate reference vehicle speed value VLb, the correction coefficients Hm, Htmp, Hpr, Hws, and the deceleration flag FLGg has not been received (S91: No), the CPU 41 repeats the determination of step S91 until the appropriate reference vehicle speed value VLb, the correction coefficients Hm, Htmp, Hpr, Hws, and the deceleration flag FLGg have been received. On the other hand, if the appropriate reference vehicle speed value VLb, the correction coefficients Hm, Htmp, Hpr, Hws, and the deceleration flag FLGg have been received (S91: Yes), the CPU 41 proceeds to step S93.

[0153] In step S93, the CPU 41, similar to step S19 above, derives the product of the appropriate reference vehicle speed value VLb and the mode correction coefficient Hm as the corrected appropriate reference vehicle speed value VLb1. In the following step S95, similar to step S25 above, the CPU 41 derives the product of the appropriate reference vehicle speed value VLb1 and the tire temperature correction coefficient Htmp as the first candidate vehicle speed value VLa1. Next, in step S97, similar to step S29 above, the CPU 41 derives the product of the appropriate reference vehicle speed value VLb1 and the precipitation correction coefficient Hpr as the second candidate vehicle speed value VLa2. In the following step S99, similar to step S33 above, the CPU 41 derives the product of the appropriate reference vehicle speed value VLb1 and the wind volume correction coefficient Hws as the third candidate vehicle speed value VLa3.

[0154] Then, in step S101 , the CPU 41 derives the appropriate vehicle speed value VLa based on the first vehicle speed candidate value VLa1 , the second vehicle speed candidate value VLa2 , and the third vehicle speed candidate value VLa3 , similarly to the above-described step S35 .

[0155] In the following step S103, the CPU 41 obtains the road surface condition of the driving area ARD, similarly to the aforementioned step S53. Subsequently, in step S105, the CPU 41 derives the appropriate vehicle speed value VL based on the appropriate vehicle speed value VLa and the road surface condition, similarly to the aforementioned step S55. Then, in step S107, the CPU 41 implements speed assist control, similarly to the aforementioned step S57.

[0156] In step S109, the CPU 41 determines whether the deceleration flag FLGg is on, similar to step S59 described above. If the deceleration flag FLGg is on (S109: Yes), the CPU 41 transfers the process to step S111. On the other hand, if the deceleration flag FLGg is off (S109: No), the CPU 41 temporarily terminates this processing routine.

[0157] In step S111, the CPU 41 performs the turn preparation control in the same manner as in step S61 described above. Then, the CPU 41 temporarily terminates this processing routine.

[0158] <Correspondence>

[0159] The correspondence between the matters in this embodiment and the matters described in the above-mentioned "means for solving the problem" column is as follows.

[0160] Step S21 corresponds to the "temperature acquisition process." Steps S93 to S101 and S105 correspond to the "appropriate value setting process." In the present embodiment, a plurality of candidate vehicle speed values ​​are derived, and the appropriate vehicle speed value VL is set based on each candidate vehicle speed value. In particular, step S95 corresponds to a process for deriving a first candidate vehicle speed value VLa1 that is smaller as the tire temperature TMPty decreases. Steps S97 and S99 correspond to a process for deriving candidate vehicle speed values ​​VLa2 and VLa3 based on weather information. Step S93 corresponds to a process for setting the appropriate vehicle speed value VL based on the driving mode MD selected by the driver. Step S105 corresponds to a process for setting the appropriate vehicle speed value VL based on the road surface condition.

[0161] Steps S107 and S111 correspond to "assistance processing." In particular, step S107 corresponds to "speed assist control," which performs at least one of reporting the appropriate vehicle speed value VL to the driver and decelerating the vehicle when the vehicle speed V exceeds the appropriate vehicle speed value VL. Furthermore, step S111 corresponds to "turn preparation control." Step S13 corresponds to "determination processing." Step S103 corresponds to "road surface condition acquisition processing."

[0162] The storage device 24 of the server control device 21 corresponds to the "storage device." The CPU 22 of the server control device 21 and the CPU 41 of the vehicle control device 40 correspond to the "execution device." Furthermore, the CPU 41 of the vehicle control device 40 corresponds to the "second execution device," and the CPU 22 of the server control device 21 corresponds to the "first execution device."

[0163] Each of the vehicle speed candidate values ​​VLa1 to VLa3 corresponds to a “candidate value of the appropriate vehicle speed value.” Among the vehicle speed candidate values ​​VLa1 to VLa3 , the first vehicle speed candidate value VLa1 corresponds to a “candidate value” derived to be smaller as the tire temperature TMPty decreases.

[0164] <Functions and Effects of the Third Embodiment>

[0165] According to this embodiment, in addition to the effects equivalent to the effects (1-1) to (1-9) in the above-mentioned first embodiment, the following effects can be obtained.

[0166] (3-1) In this embodiment, in the first embodiment, the CPU 41 of the vehicle control device 40 executes a portion of the processing executed by the CPU 22 of the server control device 21. This reduces the control load of the server control device 21.

[0167] <Change Example>

[0168] The above-mentioned embodiments can be implemented by modification as follows. The above-mentioned embodiments and the following modifications can be implemented in combination with each other within the scope of no technical contradiction.

[0169] In the above embodiments, the processes constituting the driving assistance method are shared between the CPU 22 of the server control device 21 and the CPU 41 of the vehicle control device 40. However, the CPU 41 of the vehicle control device 40 may execute all the processes constituting the driving assistance method.

[0170] In this case, when the vehicle 30 is traveling on the track 101 managed by the server 20, before starting to travel, Figure 3 The entire driving area AR shown, Figure 4 The map MP shown, Figure 5 or Figure 8 The tables TL and TL1 shown are transmitted from the server 20 to the vehicle 30 . Then, the received various information is stored in the storage device 43 of the vehicle control device 40 .

[0171] When the vehicle 30 is traveling on the race track 101 in this state, the CPU 41 can set the appropriate vehicle speed value VL in the same manner as in the above-described embodiments.

[0172] In this modified example, the CPU 41 of the vehicle control device 40 corresponds to the “execution device”, and the storage device 43 corresponds to the “storage device”.

[0173] In each of the above-described embodiments, only one of the deceleration assist control and the turn preparation control is performed. However, both the deceleration assist control and the turn preparation control may be performed.

[0174] The driver may select the control to be executed from the deceleration assist control and the turn preparation control based on the driving mode MD selected. For example, when the first driving mode MD1 is selected, both the deceleration assist control and the turn preparation control may be executed. Furthermore, when the second driving mode MD2 is selected, only the deceleration assist control may be executed. Furthermore, when the third driving mode MD3 is selected, only the turn preparation control may be executed.

[0175] The deceleration distance Lg may not be changed according to the driving mode MD selected by the driver.

[0176] The deceleration request value DecR may not be changed according to the driving mode MD selected by the driver.

[0177] The assist process may not include either the deceleration assist control or the turn preparation control.

[0178] In each of the above embodiments, the minimum value among the first candidate vehicle speed value VLa1, the second candidate vehicle speed value VLa2, and the third candidate vehicle speed value VLa3 is derived as the appropriate vehicle speed value VLa. However, this is not limiting. In other words, any value can be derived based on the first candidate vehicle speed value VLa1, the second candidate vehicle speed value VLa2, and the third candidate vehicle speed value VLa3. For example, the average of the plurality of candidate vehicle speed values ​​VLa1, VLa2, and VLa3 may be used to derive the appropriate vehicle speed value VL. Furthermore, for example, the second smallest value among the plurality of candidate vehicle speed values ​​VLa1, VLa2, and VLa3 may be used to derive the appropriate vehicle speed value VL.

[0179] In each of the above embodiments, the appropriate vehicle speed value VL can be changed according to the driving mode MD selected by the driver, but the present invention is not limited thereto. That is, the appropriate vehicle speed value VL may be changed independently of the driving mode MD selected by the driver.

[0180] In the above-described embodiments, the appropriate vehicle speed value VL can be changed according to the amount of precipitation at the circuit 100 , but the present invention is not limited thereto.

[0181] In each of the above embodiments, the appropriate vehicle speed value VL can be changed according to the wind volume of the circuit 100 , but the present invention is not limited thereto.

[0182] In each of the above embodiments, the appropriate vehicle speed value VL can be changed according to the weather at the racetrack 100 , but the present invention is not limited thereto.

[0183] If the appropriate vehicle speed value VL is corrected based on the estimated value of road surface μ, the appropriate vehicle speed value VL may be corrected based on the estimated value of road surface μ using a method different from the method described in the above embodiments. For example, the appropriate vehicle speed value VL may be corrected so that the smaller the estimated value of road surface μ, the larger the correction amount.

[0184] The vehicle speed may not be changed based on the estimated value of the road surface μ. In this case, the road surface state acquisition process may be omitted.

[0185] The appropriate vehicle speed value VL may not be changed according to the traveling area ARD. In this case, the determination process may not be executed.

[0186] In the above embodiments, the tire temperature TMPty is obtained based on the number of laps, but the present invention is not limited thereto. For example, the distance traveled by the vehicle 30 after starting on the track 101 may be measured, and a value corresponding to the measured distance may be obtained as the tire temperature TMPty.

[0187] Acquiring tire temperature TMPty based on the distance traveled by vehicle 30 after starting on track 101 is an example. For example, if vehicle 30 includes a detection system for detecting tire temperature, the detected value of the tire temperature may be acquired as tire temperature TMPty.

[0188] In the speed assist control, if the appropriate vehicle speed value VL is reported to the driver, the control for decelerating the vehicle 30 when the vehicle speed V exceeds the appropriate vehicle speed value VL does not need to be performed.

[0189] In the speed assist control, if the control of decelerating the vehicle 30 is performed when the vehicle speed V exceeds the appropriate vehicle speed value VL, the control of reporting the appropriate vehicle speed value VL to the driver may not be performed.

[0190] In the first and third embodiments described above, when the driver performs a brake operation during execution of the turn preparation control, the speed assist control may not be executed.

[0191] In each of the above embodiments, a vehicle 30 having three driving modes MD1 to MD3 as driver-selectable driving modes MD is used, but the present invention is not limited thereto. For example, a vehicle having two driver-selectable driving modes MD may be used as vehicle 30. Furthermore, a vehicle having four or more driver-selectable driving modes MD may be used as vehicle 30.

[0192] In each of the above-described embodiments, a vehicle in which the driver cannot select the driving mode MD may be applied as the vehicle 30. In this case, the appropriate vehicle speed value VL cannot be changed according to the driving mode.

[0193] While the above embodiment describes a case where the vehicle 30 is traveling on the track 101 of the racetrack 100, the present invention is not limited thereto. For example, the driving assistance system can also be applied when the vehicle 30 is traveling on a road. Specifically, while the vehicle 30 is traveling on the road, the tire temperature TMPty is acquired. Then, a smaller value, as the tire temperature TMPty decreases, is derived as a candidate value for the appropriate vehicle speed value, and the appropriate vehicle speed value VL is set based on this candidate value. In this case, the assistance process is also executed based on the appropriate vehicle speed value VL.

[0194] The driving support system 10 is not limited to a system that includes a CPU and a memory storing a program and executes software processing. That is, the driving support system 10 may have any one of the following configurations (a) to (c).

[0195] (a) The driving assistance system 10 includes one or more processors that execute various processes according to computer programs. The processors include a CPU and memory such as RAM and ROM. The memory stores program code or instructions that cause the CPU to execute processes. Memory, or computer-readable media, includes any available media that can be accessed by a general-purpose or special-purpose computer.

[0196] (b) The driving assistance system 10 includes one or more dedicated hardware circuits that perform various processes. Examples of dedicated hardware circuits include application-specific integrated circuits (ASICs) or FPGAs. ASIC stands for "Application Specific Integrated Circuit," and FPGA stands for "Field Programmable Gate Array."

[0197] (c) The driving support system 10 includes a processor that executes part of various processes according to a computer program, and a dedicated hardware circuit that executes the remaining processes among the various processes.

[0198] Next, technical ideas that can be grasped from the above-mentioned embodiments and modifications will be described.

[0199] (1) A vehicle driving assistance system that assists a driver in operating the vehicle while the vehicle is driving, wherein:

[0200] The driving assistance system includes an execution device,

[0201] The execution device performs the following processing:

[0202] an index acquisition process of acquiring, when the vehicle is traveling on a specific track, an index of the driver's familiarity with vehicle operations for traveling the vehicle on the track;

[0203] An appropriate value setting process of setting an appropriate vehicle speed, that is, an appropriate vehicle speed value, when the vehicle is traveling; and

[0204] assisting processing, performing at least one of a process of reporting the appropriate vehicle speed value to the driver and a process of decelerating the vehicle when the vehicle speed exceeds the appropriate vehicle speed value,

[0205] In the appropriate value setting process, the execution device derives a value that is smaller as the degree of familiarity estimated from the index decreases as a candidate value for the appropriate vehicle speed value, and sets the appropriate vehicle speed value based on the candidate value.

[0206] When a vehicle is driven on a track with which the driver is unfamiliar, it is desirable to suppress increases in vehicle speed while ensuring vehicle safety. Therefore, in the above configuration, if the driver is unfamiliar with the vehicle's operation when driving on a specific track, a smaller value is set as the appropriate vehicle speed value than when the driver is familiar with the vehicle's operation on that track. Furthermore, through auxiliary processing, the appropriate vehicle speed value is reported to the driver, or the vehicle is decelerated so that the vehicle speed does not exceed the appropriate vehicle speed value. In other words, the above configuration allows the appropriate vehicle speed value to be set to a value corresponding to the driver's level of familiarity.

Claims

1. A vehicle driving assistance system that assists the driver in vehicle operation while the vehicle is driving, wherein: The driving assistance system includes an execution device, The execution device performs the following processing: Temperature acquisition processing, acquiring the temperature of the tire of the vehicle, that is, the tire temperature; An appropriate value setting process is to set an appropriate vehicle speed, i.e., an appropriate vehicle speed value, when the vehicle is traveling; and assisting processing, performing at least one of a process of reporting the appropriate vehicle speed value to the driver and a process of decelerating the vehicle when the vehicle speed exceeds the appropriate vehicle speed value, The execution device derives a value that becomes smaller as the tire temperature decreases as a candidate value for the vehicle speed appropriate value in the appropriate value setting process, and sets the vehicle speed appropriate value based on the candidate value. The execution device acquires a higher temperature as the tire temperature as the travel distance from the start of the vehicle increases during the temperature acquisition process. The driving assistance system includes a storage device that divides a road on which the vehicle is traveling into a plurality of driving areas and stores the divided roads. The storage device includes a map that stores a reference vehicle speed appropriateness value, that is, a reference vehicle speed appropriateness value, for each of the plurality of driving areas. The execution device executes a determination process of determining a driving area in which the vehicle is traveling, that is, a driving area, from among the plurality of driving areas. In the appropriate value setting process, the candidate value is derived based on the appropriate reference vehicle speed value corresponding to the traveling area and the tire temperature acquired from the map.

2. The driving assistance system for a vehicle according to claim 1, wherein: The execution device executes a road surface state acquisition process for acquiring a road surface μ as a state of the road surface on which the vehicle is traveling, that is, a road surface state. In the appropriate value setting process, when the road surface μ is low, a smaller value than when the road surface μ is high is set as the appropriate vehicle speed value.

3. The driving assistance system for a vehicle according to claim 1 or claim 2, wherein: The execution device sets the appropriate vehicle speed value based on weather information, which is information related to weather, in the appropriate value setting process.

4. The driving assistance system for a vehicle according to claim 1 or claim 2, wherein: In the vehicle, a first driving mode and a second driving mode are prepared as driving modes selectable by the driver. The first driving mode is a driving mode in which the vehicle speed is suppressed from increasing compared to the second driving mode. In the appropriate value setting process, the execution device sets, when the driver selects the first driving mode, a value smaller than that when the driver selects the second driving mode, as the appropriate vehicle speed value.

5. The driving assistance system for a vehicle according to claim 4, wherein: The auxiliary processing includes a turning preparation control for requesting the driver to decelerate the vehicle in preparation for the vehicle entering a curve. In the assist process, the execution device starts the turn preparation control closer to the curve when the driver selects the first driving mode than when the driver selects the second driving mode.

6. The driving assistance system for a vehicle according to claim 4, wherein: The assist process includes a deceleration assist control for controlling the deceleration of the vehicle in preparation for the vehicle entering a curve. The execution device executes a deceleration request value setting process for setting a deceleration request value, that is, a deceleration request value, which is a request value for deceleration of the vehicle. In the deceleration assist control, the deceleration of the vehicle is controlled based on the deceleration request value. In the deceleration request value setting process, the execution device sets, when the driver selects the first driving mode, a value smaller than that when the driver selects the second driving mode, as the deceleration request value.

7. The driving assistance system for a vehicle according to claim 1 or claim 2, wherein: The execution device includes: a first execution device, which is arranged outside the vehicle; and a second execution device, which is arranged on the vehicle. The first execution device and the second execution device can send and receive information to each other. The second executing device executes a portion of the processes including the auxiliary process, and the first executing device executes the remaining processes.

8. A vehicle driving assistance method for assisting a driver in vehicle operation while the vehicle is driving, wherein: The driving assistance method includes the following processing: Temperature acquisition processing, acquiring the temperature of the tire of the vehicle, that is, the tire temperature; An appropriate value setting process is to set an appropriate vehicle speed, i.e., an appropriate vehicle speed value, when the vehicle is traveling; and an auxiliary process for performing at least one of a process of reporting the appropriate vehicle speed value set in the appropriate value setting process to the driver and a process of decelerating the vehicle when the vehicle speed exceeds the appropriate vehicle speed value; causing an execution device mounted on the vehicle to execute the auxiliary process, wherein in the appropriate value setting process, a value that is smaller as the tire temperature acquired in the temperature acquisition process is lower is derived as a candidate value for the appropriate vehicle speed value, and the appropriate vehicle speed value is set based on the candidate value; In the temperature acquisition process, the longer the travel distance from the start of the vehicle, the higher the temperature acquired as the tire temperature. The road on which the vehicle travels is divided into a plurality of travel areas and stored in a storage device. The storage device has a map that stores a reference vehicle speed appropriate value, that is, a reference vehicle speed appropriate value, for each of the plurality of travel areas. The driving assist method includes determining a driving area in which the vehicle is traveling, that is, a driving area, from among the plurality of driving areas. In the appropriate value setting process, the candidate value is derived based on the appropriate reference vehicle speed value corresponding to the traveling area and the tire temperature acquired from the map.

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