Drive mode recommendation method and drive mode recommendation system

Abstract

According to the present invention, a drive mode recommendation method for recommending a drive mode for setting the driving characteristics of a vehicle to a driver is executed by a controller. The controller determines the road surface conditions of a road on which the vehicle travels on the basis of an image captured by a camera 5 mounted on the vehicle. On the basis of a determination result regarding the road surface conditions, the controller selects a recommended mode to recommend to the driver from among a plurality of preset drive modes. If the recommended mode is determined to be highly probable, the controller suggests, to the driver, changing to the recommended mode.

Description

Drive mode recommendation method and drive mode recommendation system

[0001] The present invention relates to a driving mode recommendation method and a driving mode recommendation system.

[0002] Patent Document 1 discloses a road surface condition estimation device. A camera acquires a road surface image in the vehicle's traveling direction, and a road surface condition estimation unit detects preset road surface pattern information from the acquired road surface image. The road surface condition estimation unit estimates the road surface condition of the entire range of the road surface image based on the detected pattern information and the occupancy state of the pattern information within the road surface image. A control unit provides the estimated road surface condition to various on-board devices, such as stabilizers and suspensions, and performs control appropriate to the road surface condition.

[0003] JP 2013-213793 A

[0004] However, the method disclosed in Patent Document 1 has a problem in that the control of the in-vehicle device is frequently switched in response to changes in the road surface conditions in the image.

[0005] An object of the present invention is to provide a drive mode recommendation method and a drive mode recommendation system that can appropriately recommend a drive mode.

[0006] A drive mode recommendation method according to one aspect of the present invention determines the road surface conditions of a road on which a vehicle is traveling based on information obtained from a sensor. A recommended mode, which is a drive mode recommended to a driver, is selected based on the result of the road surface condition determination. If the recommended mode has a high degree of accuracy, a change to the recommended mode is suggested to the driver.

[0007] According to one aspect of the present invention, a drive mode can be appropriately recommended to a driver.

[0008] FIG. 1 is a block diagram showing the configuration of a drive mode recommendation system according to this embodiment. FIG. 2 is a diagram showing an example of road surface condition determination. FIG. 3 is a diagram showing the correspondence between a determined road surface and a recommended mode. FIG. 4 is a diagram illustrating a screen displayed on a display. FIG. 5 is a diagram showing another example of displaying road surface condition information. FIG. 6 is a flowchart showing a drive mode recommendation method by the drive mode recommendation system. FIG. 7 is a flowchart showing a road surface determination correction method. FIG. 8 is a flowchart showing a method of determining display timing. FIG. 9 is a flowchart showing a method of determining display timing. FIG. 10 is a diagram showing a display proposing a change to the recommended mode. FIG. 11 is a diagram showing a display proposing a change to the recommended mode. FIG. 12 is a diagram showing a display proposing a change to the recommended mode. FIG. 13 is a diagram showing a display proposing a change to the recommended mode.

[0009] A drive mode recommendation system 1 according to this embodiment will be described with reference to FIG. 1. The drive mode recommendation system is installed in a vehicle that is manually driven by a driver. The vehicle may be a vehicle that can switch between manual driving and automatic driving. The automatic driving function may be a function that automatically controls multiple vehicle control functions, such as a steering control function, a braking force control function, and a driving force control function, to drive the vehicle autonomously (fully automatic driving function), or a function that automatically controls only some of the multiple vehicle control functions to assist the driver in driving.

[0010] The drive mode recommendation system 1 is a system that recommends an optimal drive mode to a driver. The drive mode is a mode for setting the driving characteristics of the vehicle, i.e., the control characteristics of vehicle control devices such as the powertrain and transmission. Depending on the drive mode, characteristics such as the powertrain output relative to the accelerator opening, maximum output and response, the shift line of the transmission shift map, the drive force distribution to the four wheels, and the control amount of the brake LSD control are set.

[0011] The vehicle has five drive modes, including, for example, OFF ROAD, SNOW, STANDARD, ECO, and SPORT, and one of the five drive modes selected by the driver is applied to the vehicle.

[0012] Below, we briefly explain the representative drive modes: off-road, snow, and standard. Off-road is a drive mode that facilitates starting and driving on uneven or step-prone unpaved roads, uphill climbs, or sandy surfaces. Snow is a drive mode that facilitates starting and driving on snow-covered or icy roads. Standard is the optimal drive mode for normal driving on paved roads. The powertrain output, maximum output, and response to accelerator pedal depression are set to be greater in standard than in snow, and greater in off-road than in standard. The shift line is set to be lower in off-road than in standard, and higher in snow than in standard. The drive force distribution to the four wheels is set to be approximately equal between the front and rear wheels in off-road and snow, and is set to be closer to the main drive shaft in standard. The brake LSD control amount is set to be stronger in off-road and snow than in standard.

[0013] The drive mode recommendation system 1 includes a road condition determination unit 2 , a recommended mode processing unit 3 , a drive mode switching unit 4 , a camera 5 , a decision switch 6 , a display 7 , and a drive mode switch 8 .

[0014] The road surface condition determination unit 2, the recommended mode processing unit 3, and the drive mode switching unit 4 are controllers for realizing the respective functions described below, and each controller is configured by a computer having a hardware processor such as a CPU (Central Processing Unit), memory, and various interfaces. Although each controller realizes its function using software, it is also possible to realize its function using dedicated hardware. Each controller may be a separate computer, or may be a single shared computer. The functions of the road surface condition determination unit 2, the recommended mode processing unit 3, and the drive mode switching unit 4 will be described below.

[0015] The camera 5 captures an image of the road on which the vehicle is traveling and outputs the captured image. The camera 5 is equipped with a solid-state image sensor such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The image captured by the camera 5 is, for example, a color image. The camera 5 captures an image of a predetermined range including the road ahead of the vehicle by adjusting the focal length, the lens angle of view, the vertical and horizontal mounting states, etc. The camera 5 captures images at a predetermined frame rate and outputs the captured forward image to the road surface condition determination unit 2.

[0016] The decision switch 6 is a switch for making various settings and decisions and is operated by the driver. The decision switch 6 is, for example, a steering switch provided on the steering wheel, but may be realized by operating means other than a steering switch.

[0017] The display 7 is disposed in a position visible to the driver and displays various information to be presented to the driver. The display 7 is, for example, a meter display disposed in a meter unit including a tachometer and a speedometer, but may be any other display mounted in the vehicle.

[0018] The drive mode switch 8 is a switch for selecting a drive mode and is operated by the driver. The drive mode switch 8 is located in a position where the driver can operate it, for example, on the center console. By operating the drive mode switch 8, the driver can select one drive mode from off-road, snow, standard, eco, and sport.

[0019] Next, the functions of the road surface condition determining unit 2, the recommended mode processing unit 3, and the drive mode switching unit 4 will be described.

[0020] The road surface condition determination unit 2 determines the road surface condition based on the forward image output from the camera 5. The determination result of the road surface condition is output to the recommended mode processing unit 3. The road surface condition determination unit 2 is equipped with an estimation model for determining the road surface condition from the forward image. This estimation model is, for example, a deep neural network (DNN) that learns the road surface conditions from images of roads with various road surface conditions. As shown in FIG. 2 , the road surface conditions determined by the road surface condition determination unit 2 (hereinafter referred to as the "determined road surface") include dry, wet, snow / ice, dirt, and rough. Dry refers to a dry paved road, wet refers to a wet paved road, snow / ice refers to a snow-covered or icy road, dirt refers to a gravel road, and rough refers to a sandy or muddy road. If the road surface condition does not fall into any of dry, wet, snow / ice, dirt, or rough, the road surface condition determination unit 2 determines that the road surface condition is not determinable (nolabel). The road surface condition determination unit 2 also displays the road surface condition determination result on the display 7. The road surface condition determination unit 2 repeats the process of determining the road surface condition, and updates the display content of the display 7 for each processing cycle.

[0021] The recommended mode processing unit 3 selects a drive mode (hereinafter referred to as the "recommended mode") to be recommended to the driver from among a plurality of drive modes based on the determined road surface conditions (recommended mode selection). The recommended mode selected by the recommended mode processing unit 3 is one of off-road, snow, and standard. As shown in FIG. 3 , the recommended mode processing unit 3 holds a map in which the determined road surface is associated with the recommended mode, and selects the recommended mode based on the determined road surface conditions using the map. The recommended mode processing unit 3 displays the recommended mode on the display 7. The recommended mode processing unit 3 repeats the process of selecting the recommended mode, updating the display content of the display 7 for each processing cycle.

[0022] The recommended mode processing unit 3 proposes to the driver a change to the recommended mode (mode recommendation) on the condition that the accuracy of the recommended mode selected in the current processing cycle is high. A high accuracy of the recommended mode means that there is a high possibility that the current recommended mode will continue to be selected in the future. The accuracy of the recommended mode is determined based on the environment around the vehicle (location, altitude, temperature, weather, etc.), the conditions of the road on which the vehicle is currently or will be traveling, etc. The recommended mode processing unit 3 displays information proposing a change to the recommended mode on the display 7. When the driver operates the decision switch 6 in response to this proposal, decision switch information is input to the recommended mode processing unit 3. If the decision switch information indicates that the change to the recommended mode is acceptable, the recommended mode processing unit 3 outputs a request to change to the recommended mode to the drive mode switching unit 4.

[0023] The recommended mode processing unit 3 also has a function of correcting the road surface condition determination result by the road surface condition determination unit 2 prior to the recommended mode determination process (determined road surface correction). Various information is input to the recommended mode processing unit 3 in order to select a recommended mode, correct the determined road surface, and recommend a mode. The various information includes information from various systems, control devices, and sensors installed in the vehicle.

[0024] When a request to change to the recommended mode is input from the recommended mode processing unit 3, the drive mode switching unit 4 switches the drive mode from the drive mode currently applied to the vehicle (hereinafter referred to as the "current mode") to the recommended mode. Furthermore, when the driver operates the drive mode switch 8 to switch the drive mode, mode switch information is input to the recommended mode processing unit 3. The mode switch information includes information about the drive mode selected by the driver. When the mode switch information is input, the drive mode switching unit 4 switches the drive mode from the current mode to the drive mode selected by the driver. The drive mode switching unit 4 outputs information (mode information) about the new drive mode to be switched to, to a controller that controls the vehicle control equipment. As a result, the new drive mode is applied to the vehicle.

[0025] 4, a screen 70 displayed on the display 7 will be described. Drive mode information 71 related to the drive mode and road surface condition information 75 related to the determination result of the road surface condition are displayed on the screen 70. The drive mode information 71 and the road surface condition information 75 are arranged side by side in the left-right direction.

[0026] The drive mode information 71 includes mode type information 72, current mode information 73, and recommended mode information 74. The mode type information 72 indicates five drive modes and is arranged at equal intervals on a circle having a predetermined radius. The mode type information 72 is composed of character strings indicating the names of the drive modes, but may also be icons, etc. The current mode information 73 is information indicating the current mode. The current mode information 73 is composed of, for example, an arc-shaped guide and is displayed at a position corresponding to the current mode. In the example shown in FIG. 4, the current mode is indicated as "off-road." The recommended mode information 74 is information indicating a recommended mode. The recommended mode information 74 is composed of, for example, an arc-shaped guide and is displayed at a position corresponding to the recommended mode. In the example shown in FIG. 4, the recommended mode is indicated as "snow." In FIG. 4, all five drive modes are shown to explain the mode type information 72. However, it is sufficient if only the mode type information 72 corresponding to the current mode and the recommended mode is displayed. The mode type information 72 corresponding to the other drive modes is not displayed or is displayed in a less prominent form than the mode type information 72 corresponding to the current mode and the recommended mode.

[0027] The road surface condition information 75 includes determined road surface information 76 and determination frequency information 77, 78. The determined road surface information 76 is information indicating five types of determined road surfaces and is arranged at equal intervals in the vertical direction. The determined road surface information 76 is made up of character strings (DRY, WET, SNOW, DIRT, ROUGH) for identifying the five types of determined road surfaces. The determination frequency information 77, 78 is information indicating, as a percentage, the frequency of road surface conditions determined by the road surface condition determination unit 2 over a certain period of time in the past. The determination frequency information 77, 78 is made up of a number indicating the determination frequency and a scale indicating the determination frequency.

[0028] The road surface condition information 75 is not limited to the above-described form, and may also be in a form such as that shown in Fig. 5. The road surface condition information 75 shown in Fig. 5 includes a two-dimensional area 82 made up of a vertical axis 80 indicating the likelihood of slippage and a horizontal axis 81 indicating running resistance. In the two-dimensional area 82, information indicating five types of determined road surfaces is displayed in correspondence with the vertical axis 80 and the horizontal axis 81. This road surface condition information 75 also includes determination result information 83 indicating the determination result of the road surface conditions. The determination result information 83 is, for example, a circular mark, and is displayed in the two-dimensional area 82 at a position corresponding to the determination result of the road surface conditions.

[0029] The drive mode recommendation method according to this embodiment will be described below with reference to Fig. 6. This drive mode recommendation method is executed by a controller that realizes the functions of the road surface condition determination unit 2, the recommended mode processing unit 3, and the drive mode switching unit 4.

[0030] The recommendation mode processing unit 3 determines whether the drive mode recommendation function is enabled (S1). For example, the driver can operate the operation menu by operating the decision switch 6. The driver can turn the drive mode recommendation function on or off by selecting each item in the operation menu. The recommendation mode processing unit 3 determines whether the driver is a novice driver (S2). A self-motivated driver includes not only a driver with little driving experience but also a driver who has only rarely driven the vehicle. Each time the driver uses the vehicle, the driver's login information is recorded in the vehicle. The recommendation mode processing unit 3 determines whether the driver is a novice driver based on the login information. The recommendation mode processing unit 3 determines whether a prohibition condition exists (S3). The prohibition condition defines a condition under which the execution of the drive mode recommendation system is inappropriate. Examples of the prohibition condition include a large computational processing load on the entire vehicle, a lack of spare processing capacity in the controller, and fully automated driving. If a positive determination is made in all of steps S1-S3, the process proceeds to step S4 and subsequent steps. On the other hand, if a negative determination is made in any one of steps S1 to S3, this process ends.

[0031] The road surface condition determining unit 2 determines the road surface condition based on the forward image output from the camera 5 (S4).

[0032] The recommended mode processing unit 3 performs road surface determination correction to correct the road surface conditions determined by the road surface condition determination unit 2 (S5). Even if road surface conditions differ, they may appear as similar features on an image, making it difficult to accurately determine the road surface conditions. For example, wet roads and icy roads have similar features on an image, making it difficult to distinguish between them. Therefore, the recommended mode processing unit 3 performs road surface determination correction based on the environment in which the vehicle is traveling and the vehicle's driving load.

[0033] Specifically, as shown in FIG. 7 , the recommendation mode processing unit 3 determines whether the outside air temperature is equal to or lower than a threshold temperature for determining whether the road surface is icy (S50). If the outside air temperature is equal to or lower than the threshold temperature, the recommendation mode processing unit 3 corrects the determination result of "wet" to "snow / ice" (S51). The recommendation mode processing unit 3 determines whether the driving load is equal to or higher than a threshold load (S52). The driving load is determined from the load of the motor driving the vehicle or the estimated output of the engine driving the vehicle. If the driving load is equal to or higher than the threshold load, the recommendation mode processing unit 3 corrects the determination result of "dirt" to "rough" (S53). In step S54, the recommendation mode processing unit 3 determines the corrected road surface condition as the final road surface condition.

[0034] 7 is an example. The recommended mode processing unit 3 can perform road surface determination correction for road surface conditions that appear as similar features on the image.

[0035] As shown in FIG. 6, the recommended mode processing unit 3 selects a recommended mode from three types of drive modes based on the result of the road surface condition determination (S6).

[0036] The recommended mode processing unit 3 determines the timing for proposing a change to the recommended mode (S7: timing determination process). The timing determination process will be described below with reference to FIG.

[0037] The recommended mode processing unit 3 determines whether the recommended mode selected in this processing cycle has changed from the recommended mode selected in the previous processing cycle (S70). If the recommended mode has not changed, the process returns to step S4 described above. If the recommended mode has changed, the process proceeds to step S71. When the process returns to step S4, a new processing cycle begins, in which the road surface conditions are determined and a recommended mode is selected (the same applies below).

[0038] The recommended mode processing unit 3 determines whether or not there is a recommended mode (S71). If the road surface conditions cannot be determined and there is no recommended mode, the process returns to step S4 described above. If a recommended mode has been selected from the five drive modes, the process proceeds to step S72. Note that if there is no recommended mode, the recommended mode processing unit 3 preferably does not display recommended mode information 74 on the display 7.

[0039] The recommended mode processing unit 3 determines whether the recommended mode is snow and whether wheel slippage is occurring on the vehicle (S72). When traveling on a snowy or icy road, wheel slippage can occur on the vehicle's wheels. Therefore, if wheel slippage occurs, it is assumed that the road surface condition is snowy or icy. Therefore, the recommended mode processing unit 3 can determine whether the accuracy of the recommended mode is high by considering the current recommended mode and the state of the vehicle's wheels. If the determination in step S72 is affirmative, it is determined that the recommended mode is highly likely to be snow, and the process proceeds to step S82, described below, to suggest a change to the recommended mode. If the determination in step S72 is negative, the process proceeds to step S73.

[0040] The recommended mode processing unit 3 determines whether the frequency of the proposal to change to the recommended mode is appropriate (S73). If the proposal frequency is high, the driver may find the drive mode recommendation system 1 annoying. Therefore, the recommended mode processing unit 3 determines whether the proposal frequency is appropriate, for example, by the following method. If the duration of the current mode selected by the driver is shorter than a predetermined time, the recommended mode processing unit 3 determines that the proposal frequency is inappropriate. Alternatively, if the duration since the previous proposal to change to the recommended mode is shorter than a predetermined time, the recommended mode processing unit 3 determines that the proposal frequency is inappropriate. If the determination in step S73 is affirmative, the process proceeds to step S74. If the determination in step S73 is negative, the process returns to step S4. Note that the recommended mode processing unit 3 may also determine that the proposal frequency is inappropriate by focusing on the recommended mode selected by the recommended mode processing unit 3 if the continuous time period during which the same recommended mode was selected from a past processing cycle to the previous processing cycle is shorter than a predetermined time.

[0041] In steps S74-S79, the recommended mode processing unit 3 determines whether the recommended mode selected in the current processing cycle is likely to continue to be selected thereafter. As described above, the recommended mode is selected based on the road surface condition determination result. The road surface condition determination result depends on the road surface conditions included in the forward image and may be affected by short-term changes in the road surface conditions. Therefore, a short-term change from one road surface condition to another may change the recommended mode, resulting in repeated suggestions to change to the recommended mode. Therefore, by performing the processing of steps S74-S79, the recommended mode processing unit 3 suggests a change to the recommended mode only in situations where it is determined that the recommended mode is likely to continue to be selected thereafter and the accuracy of the recommended mode is high.

[0042] For example, even if "Snow" is selected as the recommended mode in the current processing cycle, if the snow on the road surface is temporary, it is desirable to avoid suggesting a change to the recommended mode to "Snow." This is because if the vehicle travels a short distance and reaches a point where there is no snow, it would be necessary to suggest again a change to the recommended mode from "Snow" to "Standard." In other words, the recommended mode processing unit 3 wants to suggest a change to the recommended mode to "Snow" only in a situation where the accuracy of the recommended mode is high, i.e., it is determined that the recommended mode ("Snow") selected in the current processing cycle will continue.

[0043] If the recommended mode selected in this processing cycle is determined to be snow (YES in S74), the recommended mode processing unit 3 determines whether the road surface condition will continue to be snow / ice. Specifically, the recommended mode processing unit 3 determines whether snow accumulation on the road surface is expected to increase along the future route (S75). For example, if an increase in altitude is expected based on the vehicle's position information and altitude information obtained from the navigation system and the vehicle's direction of travel, the recommended mode processing unit 3 predicts that snow accumulation will increase in the future. The recommended mode processing unit 3 also determines whether the snow accumulation is partial (S76). For example, the recommended mode processing unit 3 determines whether the vehicle is traveling on a shaded road based on the vehicle's position and the current date and time obtained from the navigation system. Furthermore, if the temperature is determined to be low in addition to the shaded road, the recommended mode processing unit 3 determines that the snow accumulation is not partial on the road surface. If the determinations in steps S75 and S76 are both positive, the process proceeds to step S77 to suggest changing the recommended mode to snow. On the other hand, if a negative determination is made in either step S75 or S76, the process returns to step S4.

[0044] On the other hand, even if standard is selected as the recommended mode in the current processing cycle, if snow is likely to frequently appear on the road surface in the future, it is desirable to avoid making a suggestion to change the recommended mode to standard. This is because if the vehicle reaches a snowy area after traveling a short distance, it will be necessary to make another suggestion to change the recommended mode from standard to snow. In other words, the recommended mode processing unit 3 wants to make a suggestion to change the recommended mode to standard only in situations where the accuracy of the recommended mode is high, that is, in situations where it is determined that the recommended mode (standard) selected in the current processing cycle will continue.

[0045] If it is determined that the recommended mode selected in this processing cycle is standard (S77: YES), the recommended mode processing unit 3 determines whether the road surface condition will remain dry or wet. Specifically, the recommended mode processing unit 3 determines whether snow accumulation on the road surface is expected to decrease along the future route (S78). For example, if a decrease in altitude is expected based on the vehicle's position information and altitude information obtained from the navigation system and the vehicle's direction of travel, the recommended mode processing unit 3 predicts that snow accumulation will decrease in the future. The recommended mode processing unit 3 also determines whether snow accumulation is partially removed from the road surface (S76). For example, the recommended mode processing unit 3 determines whether the vehicle is traveling through a tunnel, an indoor parking lot, etc., based on information obtained from the navigation system. If the vehicle is traveling through a tunnel, an indoor parking lot, etc., the recommended mode processing unit 3 determines that snow accumulation is partially removed from the road surface. If the determination in step S78 is affirmative and the determination in step S79 is negative, the process proceeds to step S80 to propose changing the recommended mode to standard. On the other hand, if a negative determination is made in step S78 or step S79, the process returns to step S4.

[0046] The recommended mode processing unit 3 determines whether the driver has sufficient time (S80). When the driver is busy with driving operations, i.e., when the driver's driving load is high, it is preferable not to suggest a change to the recommended mode. The recommended mode processing unit 3 can determine the driver's driving load based on the driver's steering operation (angular acceleration, steering frequency, steering angle), accelerator operation (operation acceleration, operation amount, operation frequency), turn signal operation, brake operation, manual shift selection, and sport mode selection. It is also preferable not to suggest a change to the recommended mode even when the driver requires concentration. The recommended mode processing unit 3 determines that a situation requires concentration when the vehicle speed is high, when the vehicle is reversing, when a specific situation (intersection, merging, overtaking, toll booth, etc.) is confirmed from the navigation system, when an approaching emergency vehicle is detected, or when a disaster is detected. In addition, it is preferable not to suggest a change to the recommended mode when the driver's level of alertness is low, such as when the driver is drowsy or tired. The recommended mode processing unit 3 can determine the driver's level of alertness from a sensor that detects the driver's state. If the driver has the capacity, the process proceeds to step S81, and if the driver does not have the capacity, the process returns to step S4.

[0047] The recommended mode processing unit 3 determines whether the recommended mode selected in this processing cycle is different from the current mode (S81). If the recommended mode is the same as the current mode, the process proceeds to step S82, and if the recommended mode is the same as the current mode, the process returns to step S4.

[0048] The recommended mode processing unit 3 issues an instruction (display request) to the display 7 to propose a change to the recommended mode (S82). As a result, a change to the recommended mode is proposed to the driver via the display 7 (S8), as shown in FIG. 6 . Specifically, the process is as follows. First, before a change to the recommended mode is proposed, the current mode information 73 and the recommended mode information 74 on the screen 70 are displayed in positions indicating the same drive mode (e.g., standard), as shown in FIG. 10 . On the other hand, when a command to propose a change to the recommended mode is received, the recommended mode information 74 on the screen 70 is switched to a position corresponding to the recommended mode (snow), as shown in FIG. 11 . Furthermore, mode type information 72 ("SNOW") corresponding to the recommended mode is displayed. Then, after a predetermined period of time has elapsed from the display state shown in FIG. 11 , proposal information 90 proposing a change to the recommended mode is displayed on the screen 70 of the display 7, as shown in FIG. 12 . The driver can use the confirm switch 6 to accept the change to the recommended mode.

[0049] Note that instead of the proposed information 90 shown in FIG. 12 , the screen 70 of the display 7 may display proposed information 91 as a pop-up as shown in FIG. 13 . The proposed information 91 includes a selection box 92 for selecting "OK," "Cancel," and "OFF." The driver can select any of "OK," "Cancel," and "OFF" by moving the selection box 92 by operating the decision switch 6. By selecting "OK," an approval operation can be performed to accept the change to the recommended mode. By selecting "Cancel," an invalid operation can be performed to reject the change to the recommended mode. By selecting "OFF," an operation can be performed to turn off the activation setting of the drive mode recommendation function.

[0050] 6, if the driver has not operated the decision switch 6 (S9: NO), the recommendation mode processor 3 determines whether a predetermined time has elapsed since the change was suggested (S10). If the predetermined time has not elapsed, the process returns to step S9. If the predetermined time has elapsed, the recommendation mode processor 3 suspends recommending a drive mode for a certain period of time (S11).

[0051] If the driver operates the decision switch 6 (S9: YES), the recommended mode processing unit 3 determines whether "Cancel" has been selected (S12). If "Cancel" has been selected, the process proceeds to step S11 described above. If "Cancel" has not been selected, the recommended mode processing unit 3 determines whether "OK" has been selected (S13). If "OK" has been selected, the recommended mode processing unit 3 switches the drive mode to the recommended mode (S14). Specifically, the recommended mode processing unit 3 outputs a change request to the drive mode switching unit 4 to change to the recommended mode. In response, the drive mode switching unit 4 outputs information about the recommended mode (mode information) to a controller that controls the vehicle control equipment. From this point on, the new drive mode is applied to the vehicle.

[0052] 8 and 9 show an example of switching between snow and standard. However, the timing determination process can be similarly applied to switching between off-road and standard.

[0053] As described above, according to this embodiment, when it is determined that the accuracy of the recommended mode is high, a change to the recommended mode is suggested. Therefore, even if the recommended mode is switched depending on the road surface conditions in the forward image, if the accuracy of the recommended mode is not high, the suggestion to change to the recommended mode is suppressed. This can suppress the driver from feeling annoyed. On the other hand, when the accuracy of the recommended mode is high, a change to the recommended mode is suggested, so the driver will not mistakenly think that the system has stopped. In this way, the drive mode can be appropriately recommended.

[0054] According to this embodiment, if it is determined that the accuracy of the recommended mode is high and it is determined that the current mode is different from the recommended mode, a change to the recommended mode is suggested. This prevents unnecessary suggestions to the driver and allows the drive mode to be appropriately recommended.

[0055] According to this embodiment, the process of suggesting to the driver that the vehicle be changed to the recommended mode includes displaying information 90, 91 suggesting the change to the recommended mode on the display 7. This appeals to the driver's visual sense, and therefore the change to the recommended mode can be appropriately suggested.

[0056] According to this embodiment, the recommended mode selected in the current processing cycle is displayed on the display 7. This allows the driver to easily understand what drive mode is currently recommended.

[0057] According to this embodiment, if the road surface conditions cannot be determined and no recommended mode is available, no recommended mode is displayed. This allows the driver to easily understand that no recommended drive mode is available. Note that the drive mode is a function that provides the driver with ease of driving the vehicle. Naturally, the vehicle is equipped with various driving control functions, so driving stability can be maintained even when no recommended drive mode is available.

[0058] According to this embodiment, the current mode is displayed on the display 7. This allows the driver to easily understand the difference between the current mode and the recommended mode. The driver can anticipate a suggestion to change to the recommended mode, or can change the drive mode voluntarily.

[0059] According to this embodiment, the determination result of the road surface conditions is displayed on the display 7. When information suggesting a change to the recommended mode is displayed on the display 7, the determination result of the road surface conditions is switched to not being displayed. This relatively emphasizes the information suggesting a change to the recommended mode, making it possible to appropriately suggest a change to the recommended mode.

[0060] According to this embodiment, when it is determined that the recommended mode selected in the current processing cycle is likely to continue to be selected based on the environment in which the vehicle is traveling, the recommended mode is determined to have a high probability of being selected. This makes it possible to appropriately determine the situation in which the recommended mode has a high probability of being selected.

[0061] According to this embodiment, if the duration of the current mode or the duration since the last proposal to change to the recommended mode is shorter than a predetermined time, the proposal to change to the recommended mode is not made. This prevents the proposal to change to the recommended mode from being made too frequently, thereby reducing the annoyance felt by the driver.

[0062] According to this embodiment, if it is determined that the recommended mode selected in the current processing cycle has changed from the recommended mode selected in the previous processing cycle and if it is determined that the accuracy of the recommended mode selected in the current processing cycle is high, a change to the recommended mode is suggested. This allows the suggestion to change the recommended mode to be made in a timely manner in accordance with changes in road surface conditions.

[0063] According to this embodiment, when the driver's driving load is high, when the driver needs to concentrate, or when the driver's level of alertness is low, a change to the recommended mode is not suggested. As a result, a change to the recommended mode is suggested only at a timing that is acceptable to the driver, making it possible to provide a system that is easy for the driver to use.

[0064] In this embodiment, the suggestion to change the recommended mode is displayed on the display 7, but the suggestion to change the recommended mode may be output as audio from a speaker mounted on the vehicle. Furthermore, the recommended mode processing unit 3 of this embodiment estimates road surface conditions based on images captured by a camera, which is an example of a sensor that detects road surface conditions. However, the recommended mode processing unit 3 may determine road surface conditions based on information from a sensor other than a camera, such as a LiDAR (lidar) or an infrared sensor. Furthermore, in addition to the sensor mounted on the vehicle, information obtained by a sensor of another vehicle, such as probe information, may be acquired and the road surface conditions may be determined based on that information.

[0065] Although the embodiments of the present invention have been described above, the descriptions and drawings that form part of this disclosure should not be understood to limit the present invention. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure.

[0066] REFERENCE SIGNS LIST 1 Drive mode recommendation system 2 Road surface condition determination unit (controller) 3 Recommended mode processing unit (controller) 4 Drive mode switching unit (controller) 5 Camera 6 Confirmation switch 7 Display 8 Drive mode switch

Claims

1. A drive mode recommendation method executed by a controller for recommending a drive mode to a driver to set the driving characteristics of a vehicle, judging the road surface condition of the road on which the vehicle travels based on information obtained from sensors, selecting a recommended mode to be recommended to the driver from a plurality of preset drive modes based on the judgment result of the road surface condition, and when it is determined that the accuracy of the recommended mode is high, proposing to the driver to change to the recommended mode. Drive mode recommendation method.

2. The drive mode recommendation method according to claim 1, wherein when it is determined that the accuracy of the recommended mode is high and it is determined that the current mode currently applied to the vehicle is different from the recommended mode, a change to the recommended mode is proposed.

3. The process of proposing to the driver to change to the recommended mode includes displaying information for proposing a change to the recommended mode on a display visible to the driver. Drive mode recommendation method according to claim 1.

4. The drive mode recommendation method according to claim 3, wherein the recommended mode selected in the current processing cycle is displayed on the display.

5. When the road surface condition cannot be determined and there is no recommended mode, the recommended mode is not displayed. Drive mode recommendation method according to claim 4.

6. The drive mode recommendation method according to claim 4 or 5, wherein the current mode currently applied to the vehicle is displayed on the display.

7. The drive mode recommendation method according to claim 3 or 4, wherein the judgment result of the road surface condition is displayed on the display, and when information for proposing a change to the recommended mode is displayed, the judgment result of the road surface condition is switched to non-display.

8. The drive mode recommendation method according to claim 1, wherein when it is determined based on the environment in which the vehicle travels that the recommended mode selected in the current processing cycle is likely to be continuously selected thereafter, it is determined that the accuracy of the recommended mode is high.

9. The drive mode recommendation method according to claim 1, wherein when the duration of the current mode currently applied to the vehicle or the duration since the last proposal to change to the recommended mode is shorter than a predetermined time, a change to the recommended mode is not proposed.

10. The drive mode recommendation method according to claim 1, wherein when it is determined that the recommended mode selected in the current processing cycle has changed from the recommended mode selected in the previous processing cycle, and it is determined that the probability of the recommended mode selected in the current processing cycle is high, a proposal to change to the recommended mode is made.

11. The drive mode recommendation method according to claim 1, wherein when the driving load of the driver is high, when the situation requires concentration for the driver, or when the driver's wakefulness is low, a proposal to change to the recommended mode is not made.

12. A drive mode recommendation system for recommending a drive mode for setting driving characteristics of a vehicle to a driver, comprising a controller that acquires information obtained from a sensor, wherein the controller determines a road surface condition of a road on which the vehicle travels based on the information obtained from the sensor, selects a recommended mode to be recommended to the driver from a plurality of preset drive modes based on the determination result of the road surface condition, and when it is determined that the probability of the recommended mode is high, proposes to the driver a change to the recommended mode.

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