Travel mode proposal device

Abstract

This travel mode proposal device is applied to a vehicle that is provided with a plurality of travel modes for improving riding comfort for an occupant of the vehicle. A processing circuit of the travel mode proposal device functions as an acquisition unit M11 that acquires information on vehicle interior information, vehicle exterior information, and / or vehicle information of the vehicle, and an instruction unit M15 that instructs the proposal device to propose to the occupant a travel mode corresponding to the information acquired by the acquisition unit M11 among the plurality of travel modes.

Description

Driving mode suggestion device

[0001] The present invention relates to a driving mode suggestion device for suggesting a driving mode of a vehicle to an occupant of the vehicle.

[0002] Patent Literature 1 discloses a vehicle control device that controls the change in the vehicle pitch angle when braking the vehicle in order to improve the riding comfort of the vehicle occupants. The vehicle control device automatically controls the change in the vehicle pitch angle when braking the vehicle based on whether the vehicle is driven automatically or manually, the number of occupants in the vehicle, etc.

[0003] Japanese Patent Application Laid-Open No. 2019-171926

[0004] The behavior of the vehicle desired by the driver while the vehicle is running changes from time to time. Therefore, if the vehicle behavior is automatically changed as in the above-mentioned vehicle control device, the driver may feel uncomfortable with the vehicle behavior.

[0005] A driving mode suggestion device for solving the above problem is applied to a vehicle that has a plurality of driving modes prepared to improve the riding comfort of the vehicle occupants. The driving mode suggestion device includes an acquisition unit that acquires at least one of vehicle interior information, vehicle exterior information, and vehicle information of the vehicle, and an instruction unit that instructs the suggestion device to suggest to the occupants a driving mode from the plurality of driving modes that corresponds to the information acquired by the acquisition unit.

[0006] The driving mode suggestion device can contribute to suggesting to the occupant a driving mode that will not cause the occupant to feel uncomfortable with the vehicle behavior.

[0007] FIG. 1 is a diagram showing a schematic configuration of a vehicle equipped with a driving mode suggestion device of an embodiment, and a schematic configuration of an information terminal capable of communicating with the vehicle. FIG. 2 is a timing chart showing an example of a case where stop braking control is performed when braking the vehicle. FIG. 3 is a block diagram showing a functional configuration of a processing circuit provided in the driving mode suggestion device shown in FIG. 1. FIG. 4 is a timing chart showing vehicle braking accompanying a braking operation by the driver. FIG. 5 is a timing chart showing vehicle braking accompanying a braking operation by the driver. FIG. 6 is a flowchart showing a series of processes executed by a processing circuit when selecting a first driving mode in the driving mode suggestion device shown in FIG. 1. FIG. 7 is a flowchart showing a series of processes executed by a processing circuit when selecting a second driving mode in the driving mode suggestion device shown in FIG. 1. FIG. 8 is a flowchart showing a series of processes executed by the information terminal shown in FIG. 1 when proposing a driving mode selected by the driving mode suggestion device to an occupant.

[0008] An embodiment of a driving mode suggestion device will be described below with reference to Fig. 1 to Fig. 8. Fig. 1 illustrates a vehicle 10 and an information terminal 100 carried by an occupant of the vehicle 10. The vehicle 10 is equipped with a driving mode suggestion device 80.

[0009] <Information Terminal> The information terminal 100 is configured to be able to transmit and receive information to and from the driving mode suggestion device 80 mounted on the vehicle 10. The information terminal 100 is a portable information terminal that can be carried into the vehicle by an occupant. Such an information terminal 100 is, for example, a smartphone or a tablet terminal.

[0010] The information terminal 100 includes a communication device 101, a user interface 110, and a terminal control device 120. When the communication device 101 receives information transmitted from the vehicle 10, it outputs the information to the terminal control device 120. When information is input from the terminal control device 120, the communication device 101 transmits the information to the vehicle 10.

[0011] The user interface 110 has a display unit 111 and an operation unit 112. The display unit 111 displays information to be notified to the user. The operation unit 112 accepts user operations. The terminal control device 120 has a processing circuit. An example of a processing circuit is an electronic control device. In this case, the processing circuit has a CPU and a memory that stores a control program executed by the CPU. The terminal control device 120 displays a message indicating information transmitted from the vehicle 10 on the display unit 111. When the driver operates the operation unit 112, the terminal control device 120 transmits the information received by the operation unit 112 from the communication device 101 to the vehicle 10.

[0012] <Vehicle> The vehicle 10 includes a plurality of wheels, a plurality of friction brakes, a brake actuator 30, an operation system, a detection system, a communication device 60, and a control system 70. The plurality of wheels include two front wheels 12 and two rear wheels 13.

[0013] <Friction Brakes> The multiple friction brakes each apply a braking force to the corresponding wheel. Of the multiple friction brakes, the friction brake corresponding to the front wheel 12 is referred to as the "friction brake 20A," and the friction brake corresponding to the rear wheel 13 is referred to as the "friction brake 20B." The friction brakes 20A and 20B each have a wheel cylinder 21, a rotating body 22, and a friction portion 23. The rotating body 22 rotates integrally with the wheel. Therefore, braking force is applied to the wheel by pressing the friction portion 23 against the rotating body 22. The force pressing the friction portion 23 against the rotating body 22 increases as the wheel hydraulic pressure, which is the hydraulic pressure in the wheel cylinder 21, increases. Therefore, the friction brakes 20A and 20B can apply a greater braking force to the wheel as the wheel hydraulic pressure increases.

[0014] In the following description, the braking force applied to the front wheels 12 by the friction brake 20A will be referred to as the "front wheel friction braking force BPFF." The braking force applied to the rear wheels 13 by the friction brake 20B will be referred to as the "rear wheel friction braking force BPFR." The sum of the braking forces applied to the multiple wheels 12, 13 will be referred to as the "vehicle braking force BPAl." In the vehicle 10, the sum of the front wheel friction braking force BPFF and the rear wheel friction braking force BPFR corresponds to the vehicle braking force BPAl.

[0015] <Brake Actuator> The brake actuator 30 controls the wheel hydraulic pressure in the plurality of wheel cylinders 21 to control the braking force applied to the wheels 12, 13. For example, the brake actuator 30 has a pressure source that supplies brake fluid to the plurality of wheel cylinders 21. The pressure source is, for example, an electric pump and an electric cylinder. The brake actuator 30 can individually adjust the wheel hydraulic pressure in the wheel cylinder 21 for the front wheels 12 and the wheel hydraulic pressure in the wheel cylinder 21 for the rear wheels 13.

[0016] <Vehicle Driving Modes> The vehicle 10 is provided with a plurality of driving modes for improving the riding comfort of the occupants of the vehicle 10. The vehicle 10 drives according to the driving mode selected by the occupant. In this case, the vehicle 10 drives in a posture according to the driving mode selected by the occupant.

[0017] Among the multiple driving modes, the first driving mode is a driving mode in which, when stopping the vehicle 10 by applying a braking force, a vehicle-stopping braking control is implemented to suppress changes in the posture of the vehicle 10 when the vehicle is stopped. The vehicle-stopping braking control is a braking control that suppresses changes in the posture of the vehicle 10 when the vehicle is stopped by controlling the vehicle braking force BPAl before and after the vehicle is stopped. Details of the vehicle-stopping braking control will be described later.

[0018] Of the multiple driving modes, the second driving mode is a driving mode in which distribution adjustment control is implemented to suppress changes in the pitch angle θ of the vehicle 10 at the initial stage of braking. The distribution adjustment control is braking control that suppresses an increase in the pitch angle θ by adjusting the proportion of the front wheel friction braking force BPFF in the vehicle braking force BPAl. Details of the distribution adjustment control will be described later.

[0019] <Vehicle Operation System> The operation system of the vehicle 10 includes a brake operation member 15, a drive operation member, and a steering member. The brake operation member 15 is a member that the driver operates when applying braking force to the vehicle 10. An example of the brake operation member 15 is a brake pedal. The drive operation member is a member that the driver operates when accelerating the vehicle 10. An example of the drive operation member is an accelerator pedal. The steering member is a member that the driver operates when turning the vehicle 10. An example of the steering member is a steering wheel. The operation of the brake operation member 15 by the driver is called a "braking operation." The operation of the drive operation member by the driver is called an "accelerator operation." The operation of the steering member by the driver is called a "steering operation."

[0020] <Sensors Included in the Vehicle Detection System> The detection system of the vehicle 10 includes a plurality of sensors that output detection signals to the control system 70. The plurality of sensors includes a first sensor that detects a state value related to the driver's vehicle operation and a second sensor that detects a state quantity of the vehicle 10. The "vehicle operation" here includes braking operation, accelerator operation, and steering operation. The first sensor includes a brake sensor 41, an accelerator sensor 42, and a steering sensor 43. The second sensor includes a plurality of wheel speed sensors 45 and a longitudinal acceleration sensor 46.

[0021] The brake sensor 41 detects information related to the braking operation. An example of the brake sensor 41 is a stroke sensor that detects the amount of operation of the brake operating member 15 by the driver. The amount of operation based on the detection signal of the brake sensor 41 is referred to as the "braking operation amount X1." Note that the first sensor may include a sensor that detects the operating force of the brake operating member 15 by the driver.

[0022] The accelerator sensor 42 detects information related to accelerator operation. One example of the accelerator sensor 42 is a sensor that detects the amount of operation of a drive operating member. The operation amount based on the detection signal of the accelerator sensor 42 is referred to as the "accelerator operation amount X2."

[0023] The steering sensor 43 detects information related to the steering operation. An example of the steering sensor 43 is a sensor that detects the steering angle of the steering member. The steering angle based on the detection signal of the steering sensor 43 is referred to as "steering angle X3."

[0024] A wheel speed sensor 45 is provided for each of the plurality of wheels. Each of the plurality of wheel speed sensors 45 detects the rotational speed of the corresponding wheel. The rotational speed of the wheel based on the detection signal of the wheel speed sensor 45 is referred to as the "wheel speed VW." The traveling speed of the vehicle 10 calculated based on the wheel speeds VW of the plurality of wheels 12, 13 is referred to as the "vehicle speed VS."

[0025] The longitudinal acceleration sensor 46 detects the longitudinal acceleration of the vehicle 10 out of the accelerations acting on the vehicle 10. The longitudinal acceleration of the vehicle 10 based on the detection signal of the longitudinal acceleration sensor 46 is referred to as "longitudinal acceleration Gx."

[0026] <Monitoring Devices Included in the Detection System of the Vehicle> The detection system of the vehicle 10 includes an interior monitoring device 51 and an exterior monitoring device 53. The interior monitoring device 51 monitors the interior of the vehicle 10. The interior monitoring device 51 includes, for example, a plurality of cameras and an interior analysis device that analyzes image data that is data of images captured by the cameras. The plurality of cameras include a driver camera that captures an image of the driver and a passenger camera that captures an image of a passenger other than the driver.

[0027] An example of an in-vehicle analysis device is an electronic control unit. For example, the in-vehicle analysis device analyzes image data captured by a driver's camera to obtain information that can be used to estimate the driver's level of fatigue from driving. Such information includes, for example, at least one of the driver's posture, the frequency with which the driver yawns, and the frequency with which the driver blinks. The in-vehicle analysis device transmits the information obtained from the image data to the control system 70.

[0028] For example, the in-vehicle analysis device may analyze image data captured by a passenger camera to determine whether a passenger is present in the vehicle. If the in-vehicle analysis device determines that a passenger is present in the vehicle, the in-vehicle analysis device acquires information that can be used to estimate whether the passenger is exhibiting signs of motion sickness. Such information may include, for example, at least one of the passenger's posture and the frequency with which the passenger yawns. The in-vehicle analysis device transmits the information acquired from the image data to the control system 70.

[0029] The vehicle exterior monitoring device 53 monitors the periphery of the vehicle 10. The vehicle exterior monitoring device 53 includes, for example, a plurality of cameras and an in-vehicle analysis device that analyzes image data, which is data of images captured by the cameras. The plurality of cameras includes a camera that captures an image ahead of the vehicle 10 and a camera that captures an image behind the vehicle 10.

[0030] An example of an outside-vehicle analysis device is an electronic control device. For example, the outside-vehicle analysis device acquires, based on image data captured by a camera, information on the presence or absence of a preceding vehicle, the presence or absence of a following vehicle, and whether or not an obstacle exists in the traveling direction of the vehicle 10. Here, an "obstacle" is anything that may impede the traveling of the vehicle 10. The outside-vehicle analysis device also acquires information on the μ value of the road surface on which the vehicle 10 is traveling and information on the weather. The information on the μ value of the road surface includes, for example, whether or not the road surface is wet due to precipitation and whether or not there is snow. The outside-vehicle analysis device transmits the information acquired from the image data to the control system 70.

[0031] <Vehicle Communication Device> The communication device 60 transmits and receives information to the information terminal 100. When the communication device 60 receives information from the information terminal 100, it transmits the information to the control system 70. When the communication device 60 receives information from the control system 70, it transmits the information to the information terminal 100.

[0032] <Control System> The control system 70 includes a plurality of control devices. Each of the plurality of control devices has a processing circuit. An example of a processing circuit is an electronic control device. In this case, each of the plurality of processing circuits has a CPU, a first memory, and a second memory. The first memory stores a control program executed by the CPU. The second memory stores the results of CPU calculations, etc.

[0033] The multiple control devices include a braking control device 71, a drive control device 73, a steering control device 75, and a driving mode suggestion device 80. A processing circuit 71a of the braking control device 71 controls the vehicle braking force BPAl by operating the brake actuator 30. As will be described in detail later, when a first driving mode among the multiple driving modes is selected, the processing circuit 71a performs stationary braking control when applying braking force to stop the vehicle 10. Furthermore, when a second driving mode is selected, the processing circuit 71a performs distribution adjustment control at the initial stage of braking of the vehicle 10.

[0034] The processing circuit of the drive control device 73 controls the drive device of the vehicle 10. The processing circuit of the steering control device 75 controls the steering angle of the front wheels 12, which are the steered wheels. The processing circuit 81 of the driving mode suggestion device 80 has a CPU 82, a first memory 83, and a second memory 84. The CPU 82 executes a control program in the first memory 83, causing the processing circuit 81 to select a driving mode from a plurality of driving modes that suits the current situation. The processing circuit 81 then instructs the information terminal 100 to suggest the selected driving mode to the occupant. For example, the processing circuit 81 causes the communication device 60 to transmit information related to the selected driving mode to the information terminal 100. In this respect, in this embodiment, the information terminal 100 corresponds to the "suggestion device."

[0035] <Vehicle Stationary Braking Control> With reference to FIG. 2 , the vehicle stationary braking control will be described. While the vehicle 10 is traveling, the driver initiates a braking operation at timing t11. In this case, as shown in FIG. 2B, the processing circuit 71a derives a required braking force BPRq. The required braking force BPRq is a required value for the vehicle braking force BPAl. For example, the processing circuit 71a derives a required braking force BPRq such that the required braking force BPRq increases as the braking operation amount X1 of the brake operating member 15 increases. When the vehicle speed VS of the vehicle 10 is greater than the first vehicle speed determination value VSth1, as before timing t12, the processing circuit 71a sets the required braking force BPRq as the command braking force BPTr, as shown in FIG. 2D. Then, the processing circuit 71a controls the brake actuator 30 so that the vehicle braking force BPAl becomes equal to the command braking force BPTr.

[0036] When a braking force is applied to the vehicle 10 in this manner, the vehicle speed VS decreases as shown in Fig. 2A. Also, as shown in Fig. 2C, the absolute value of the longitudinal acceleration Gx increases as the vehicle braking force BPAl increases.

[0037] When the vehicle speed VS reaches the first vehicle speed determination value VSth1 at timing t12, the processing circuit 71a starts stationary braking control. The first vehicle speed determination value VSth1 is an example of a threshold value for setting the start timing of stationary braking control. From timing t12, the processing circuit 71a starts an increasing correction process for the stationary braking control. In the increasing correction process, the processing circuit 71a sets a vehicle braking force greater than the required braking force BPRq as the command braking force BPTr. For example, the processing circuit 71a sets the command braking force BPTr to the sum of the required braking force BPRq and the offset value ΔBP. Then, the processing circuit 71a controls the brake actuator 30 so that the vehicle braking force BPAl becomes the command braking force BPTr. As a result, even if the required braking force BPRq remains the same, the absolute value of the longitudinal acceleration Gx of the vehicle 10 becomes greater by the amount of the offset value ΔBP than before timing t12.

[0038] At timing t13, the vehicle speed VS becomes the second vehicle speed determination value VSth2. A vehicle speed smaller than the first vehicle speed determination value VSth1 is set as the second vehicle speed determination value VSth2. When the vehicle speed VS is equal to or smaller than the second vehicle speed determination value VSth2, it is determined that the vehicle 10 is approaching the predicted stop position PS. The predicted stop position PS is a predicted position where the vehicle 10 will stop. The processing circuit 71a shifts the processing of the stop-time braking control from an increase correction processing to a decrease correction processing. In the decrease correction processing, the processing circuit 71a reduces the command braking force BPTr. Then, the processing circuit 71a controls the brake actuator 30 so that the vehicle braking force BPAl becomes the command braking force BPTr. By performing the decrease correction processing in this manner, the processing circuit 71a causes the vehicle braking force BPAl to become smaller than the required braking force BPRq. As a result, even if the required braking force BPRq remains the same, the absolute value of the longitudinal acceleration Gx of the vehicle 10 gradually decreases.

[0039] At timing t14, the command braking force BPTr becomes equal to the holding braking force BPh. In this case, the holding braking force BPh corresponds to the "predetermined braking force." For example, the stop-maintaining braking force BPth is set as the holding braking force BPh. The stop-maintaining braking force BPth is the minimum vehicle braking force required to keep the vehicle 10 stopped on the current road surface on which the vehicle 10 is traveling, or a vehicle braking force slightly greater than the minimum vehicle braking force. From timing t14, in the reduction correction process, the processing circuit 71a maintains the command braking force BPTr at the stop-maintaining braking force BPth.

[0040] Before the vehicle 10 stops, a deceleration inertia force, which is an inertia force resulting from deceleration, acts on the vehicle 10. The deceleration inertia force is correlated with the vehicle braking force BPAl and acts on the vehicle 10 in the traveling direction. Before the vehicle 10 stops, the longitudinal acceleration Gx has a value corresponding to the deceleration inertia force. However, when the vehicle 10 stops at timing t15, the deceleration inertia force becomes 0 (zero). Therefore, as shown in FIG. 2C , the longitudinal acceleration Gx fluctuates before and after the vehicle 10 stops.

[0041] When the vehicle braking control is being performed, the vehicle braking force BPAl when the vehicle is stopped is smaller than the required braking force BPRq. Therefore, when the vehicle is stopped while the vehicle braking control is being performed, the fluctuation in the longitudinal acceleration Gx when the vehicle is stopped is smaller than when the vehicle is stopped without the vehicle braking control being performed. As described above, the smaller the fluctuation in the longitudinal acceleration Gx, the smaller the change in the posture of the vehicle 10 when the vehicle is stopped, which improves the comfort of the occupants when the vehicle is stopped.

[0042] At timing t15, the processing circuit 71a determines that the vehicle 10 has stopped, and therefore transitions the stationary braking control process from the reduction correction process to the degeneration process. In the degeneration process, the processing circuit 71a increases the command braking force BPTr. For example, the processing circuit 71a increases the command braking force BPTr to the required braking force BPRq. The processing circuit 71a controls the brake actuator 30 based on the command braking force BPTr, thereby increasing the vehicle braking force BPAl. When the command braking force BPTr becomes equal to the required braking force BPRq at timing t16, the processing circuit 71a terminates the stationary braking control.

[0043] <Distribution Adjustment Control> When the vehicle brakes, a pitching moment My is generated around the center of gravity of the vehicle. When the pitching moment My is generated in the vehicle 10, the vehicle 10 pitches toward the nose dive side. Nose dive is a behavior of the vehicle 10 that displaces the front of the body of the vehicle 10 downward and the rear of the body upward. The larger the magnitude of the pitching moment My, the larger the pitch angle θ becomes, and the faster the rate at which the pitch angle θ increases.

[0044] When the vehicle is braking, an anti-dive force FAD is applied to the front of the vehicle 10 by the suspension device for the front wheels 12. When the vehicle is braking, an anti-lift force FAL is applied to the rear of the vehicle 10 by the suspension device for the rear wheels 13. The anti-dive force FAD is a force that acts when a braking force is applied to the front wheels 12. The anti-dive force FAD is a force that prevents the front of the vehicle body from sinking. The anti-dive force FAD acts in a direction that displaces the front of the vehicle body away from the road surface. The anti-lift force FAL is a force that acts when a braking force is applied to the rear wheels 13. The anti-lift force FAL is a force that prevents the rear of the vehicle body from lifting up. The anti-lift force FAL acts in a direction that displaces the rear of the vehicle body closer to the road surface.

[0045] The vehicle 10 is configured to suppress an increase in the pitch angle θ as the front wheel braking ratio α, which is the ratio of the front wheel friction braking force BPFF to the vehicle braking force BPAl, decreases. In other words, the vehicle 10 is configured so that the pitching suppression force increases as the front wheel braking ratio α decreases. The pitching suppression force is the sum of the anti-dive force FAD and the anti-lift force FAL.

[0046] When the driver starts braking, the processing circuit 71a starts distribution adjustment control. In distribution adjustment control, the processing circuit 71a operates the brake actuator 30 so that the front wheel braking ratio α is smaller than a front wheel braking ratio reference value αB. The front wheel braking ratio reference value αB is the front wheel braking ratio when the wheel hydraulic pressures in the wheel cylinders 21 for the front wheels 12 and the wheel hydraulic pressures in the wheel cylinders 21 for the rear wheels 13 are equal to each other.

[0047] The processing circuit 71a determines whether the initial stage of braking has ended. For example, if a predetermined time has elapsed since braking began, the initial stage of braking is deemed to have ended. On the other hand, if the predetermined time has not elapsed since braking began, the initial stage of braking is deemed not to have ended. If the processing circuit 71a determines that the initial stage of braking has ended, it operates the brake actuator 30 so that the front wheel braking ratio α gradually changes toward the front wheel braking ratio reference value αB. Then, when the front wheel braking ratio α becomes equal to the front wheel braking ratio reference value αB, the processing circuit 71a terminates the distribution adjustment control.

[0048] <Driving Mode Proposal Device> The functional configuration of the driving mode proposal device 80 will be described with reference to Figures 1, 3, 4, and 5. As shown in Figures 1 and 3, the processing circuit 81 of the driving mode proposal device 80 functions as a functional unit for proposing a driving mode to the occupant and a functional unit for instructing various control devices to execute the selected driving mode, by the CPU 82 executing a control program in the first memory 83. The functional units include an acquisition unit M11, a selection unit M13, an instruction unit M15, a user request reception unit M17, and a driving mode determination unit M19.

[0049] <Acquisition Unit> The acquisition unit M11 acquires in-vehicle information, out-vehicle information, and vehicle information of the vehicle 10. The acquisition unit M11 acquires, as in-vehicle information, information that can be used to estimate the driver's fatigue level. For example, the acquisition unit M11 acquires at least one of the driver's posture, the frequency of the driver's yawning, and the frequency of the driver's blinking, all of which are transmitted from the in-vehicle monitoring device 51. The acquisition unit M11 also acquires the driver's continuous driving time.

[0050] The acquisition unit M11 acquires information about passengers as in-vehicle information. For example, the acquisition unit M11 acquires information about the presence or absence of passengers and information about whether the passengers are showing signs of motion sickness, transmitted from the in-vehicle monitoring device 51. The information about whether the passengers are showing signs of motion sickness includes at least one of the passengers' posture and the frequency with which the passengers yawn.

[0051] The acquisition unit M11 acquires, as the outside-vehicle information, information transmitted from the outside-vehicle monitoring device 53. The information transmitted from the outside-vehicle monitoring device 53 includes information on whether there is a preceding vehicle, whether there is a following vehicle, whether there is an obstacle in the traveling direction of the vehicle 10, information on the μ value of the road surface on which the vehicle 10 is traveling, and information on the weather. The acquisition unit M11 may also acquire, as the outside-vehicle information, whether there is a traffic jam in the area where the vehicle 10 is traveling.

[0052] The acquisition unit M11 acquires, as vehicle information, information related to the behavior of the vehicle 10. For example, the acquisition unit M11 acquires, as vehicle information, information related to the driver's vehicle operation. The information related to the driver's vehicle operation includes information related to the driver's braking operation, accelerator operation, and steering operation. The information related to the braking operation includes the driver's operation mode of the brake operating member 15 and the frequency with which the driver operates the brake operating member 15. The information related to the accelerator operation includes the driver's operation mode of the drive operating member and the frequency with which the driver operates the drive operating member. The information related to the steering operation includes the driver's operation mode of the steering member and the frequency with which the driver operates the steering member.

[0053] The acquisition unit M11 acquires, as vehicle information, information relating to the running state of the vehicle 10. The information relating to the running state of the vehicle 10 includes the longitudinal acceleration Gx, the vehicle body speed VS, the lateral acceleration Gy, the yaw rate Yr, etc. In other words, this information is information that can be detected by the second sensor.

[0054] <Selection Unit> The selection unit M13 selects a driving mode from among a plurality of driving modes according to the information acquired by the acquisition unit M11.

[0055] For example, the selection unit M13 selects the first driving mode when the fluctuation amount ΔGx of the longitudinal acceleration Gx when the vehicle 10 is stopped due to the application of braking force in response to the driver's braking operation is equal to or greater than the fluctuation amount threshold ΔGxth. The fluctuation amount threshold ΔGxth is set as a determination criterion based on whether the fluctuation amount ΔGx of the longitudinal acceleration when the vehicle 10 is stopped is large.

[0056] FIG. 4 is a timing chart illustrating a case in which the vehicle 10 is stopped by application of a braking force due to a braking operation by the driver. As shown in (A), (B), and (C) of FIG. 4, when the vehicle 10 is stopped at timing t21 due to application of a braking force, the longitudinal acceleration Gx fluctuates. Each time the vehicle 10 is stopped due to application of a braking force due to a braking operation by the driver, the selection unit M13 acquires a fluctuation amount ΔGx of the longitudinal acceleration at the time the vehicle 10 is stopped. Then, if the fluctuation amount ΔGx is equal to or greater than a fluctuation amount threshold ΔGxth, the selection unit M13 updates the consecutive number of times CNT1 so that the consecutive number of times CNT1 increases by one. On the other hand, if the fluctuation amount ΔGx is not equal to or greater than the fluctuation amount threshold ΔGxth, the selection unit M13 resets the consecutive number of times CNT1 to 0 (zero). If the consecutive number of times CNT1 is equal to or greater than a predetermined number of times CNT1th, the selection unit M13 selects the first driving mode. An integer equal to or greater than 2 is set as the predetermined number of times CNT1th.

[0057] Here, a skilled driver, who is a high-level driver, can adjust the braking operation amount X1 so that the fluctuation amount ΔGx is less than the fluctuation amount threshold ΔGxth when stopping the vehicle 10 by applying braking force in response to a braking operation. On the other hand, a driver who is not a skilled driver has difficulty adjusting the braking operation amount X1 so that the fluctuation amount ΔGx is less than the fluctuation amount threshold ΔGxth when stopping the vehicle 10 by applying braking force in response to a braking operation. In this respect, it can be said that the selection unit M13 selects a driving mode from among the multiple driving modes in accordance with the driver's driving skill.

[0058] The selection unit M13 selects the second driving mode when the increase rate dBPRq of the required braking force BPRq at the start of braking due to the driver's braking operation is equal to or greater than the increase rate threshold dBPRqth. The increase rate threshold dBPRqth is set as a criterion for determining whether the increase rate of the braking operation amount X1 is large.

[0059] 5A, 5B, and 5C are timing charts showing the case where the vehicle 10 is stopped by the application of braking force due to the driver's braking operation. As shown in (A), (B), and (C) of FIG. 5, the driver starts braking at timing t31 while the vehicle 10 is traveling. In this case, the period from timing t31 to timing t32 corresponds to the initial stage of braking.

[0060] When the vehicle 10 begins to decelerate due to the application of braking force, a pitching moment My is generated in the vehicle 10, increasing the pitch angle θ of the vehicle 10. In this case, the greater the rate at which the vehicle braking force BPAl increases, the earlier the magnitude of the pitching moment My increases, and therefore the greater the rate at which the pitch angle θ increases.

[0061] The selection unit M13 acquires the increase rate dBPRq of the required braking force at the beginning of vehicle braking when the application of braking force to the vehicle 10 is initiated by the driver's braking operation. If the increase rate dBPRq becomes equal to or greater than the increase rate threshold dBPRqth at the beginning of braking, the selection unit M13 updates the consecutive number CNT2 so that the consecutive number CNT2 increases by one. On the other hand, if the increase rate dBPRq does not become equal to or greater than the increase rate threshold dBPRqth at the beginning of braking, the selection unit M13 resets the consecutive number CNT2 to 0 (zero). If the consecutive number CNT2 becomes equal to or greater than a predetermined number CNT2th, the selection unit M13 selects the second driving mode. The predetermined number CNT2th is set to an integer equal to or greater than 2.

[0062] Here, when performing a braking operation, an advanced driver can adjust the braking operation amount X1 so that the increase rate of the pitch angle θ at the initial stage of braking is not too large. On the other hand, when performing a braking operation, a driver who is not good at driving cannot adjust the braking operation amount X1 so that the increase rate of the pitch angle θ at the initial stage of braking is not too large. In this respect, it can be said that the selection unit M13 selects a driving mode from among multiple driving modes according to the driving skill of the driver.

[0063] When the driver's fatigue level is equal to or greater than a threshold, the selection unit M13 selects the first and second driving modes from among the multiple driving modes. Specifically, the selection unit M13 derives a fatigue level estimate FLE, which is an estimate of the driver's fatigue level, based on information related to the fatigue level among the information acquired by the acquisition unit M11. The information related to the fatigue level includes, for example, the driver's continuous driving time, the frequency of the driver's yawning, and the frequency of the driver's blinking. In this case, the selection unit M13 may derive the fatigue level estimate FLE so that it increases as the driver's continuous driving time increases. The selection unit M13 may derive the fatigue level estimate FLE so that it increases as the driver's yawning frequency increases. The selection unit M13 may derive the fatigue level estimate FLE so that it increases as the driver's blinking frequency increases. Then, when the fatigue level estimate FLE is equal to or greater than a fatigue level threshold FLEth, the selection unit M13 selects the first and second driving modes.

[0064] The selection unit M13 selects a first driving mode and a second driving mode from among a plurality of driving modes based on information about the passenger. Specifically, the selection unit M13 determines whether the passenger is showing signs of motion sickness based on the information about the passenger among the information acquired by the acquisition unit M11. For example, the selection unit M13 estimates that the passenger is showing signs of motion sickness when the frequency of the passenger's yawning is equal to or greater than a frequency threshold. Then, when the selection unit M13 determines that the passenger is showing signs of motion sickness, it selects the first driving mode and the second driving mode.

[0065] The selection unit M13 determines whether to prohibit the execution of multiple driving modes based on the outside-vehicle information. For example, the selection unit M13 determines that the prohibition condition is met when it can be inferred from the outside-vehicle information that the road surface on which the vehicle 10 is traveling is a low μ road. For example, the selection unit M13 determines that the prohibition condition is met when it can be inferred from the outside-vehicle information that it is raining or snowing. Then, when the prohibition condition is met, the selection unit M13 does not select any driving mode.

[0066] The instruction unit M15 instructs the information terminal 100 to suggest to the occupant one of the multiple driving modes that corresponds to the information acquired by the acquisition unit M11. Specifically, the instruction unit M15 causes the communication device 60 to transmit information about the driving mode selected by the selection unit M13 to the information terminal 100.

[0067] Incidentally, in the information terminal 100, when the communication device 101 receives information about the driving mode transmitted from the communication device 60 of the vehicle 10, the communication device 101 outputs the information to the terminal control device 120. The terminal control device 120 displays on the display unit 111 a message suggesting to the occupant the driving mode indicated by the information received from the communication device 101. In this way, the terminal control device 120 can suggest a driving mode to the occupant.

[0068] The occupant decides whether or not to permit the execution of the proposed driving mode by operating the operation unit 112. The operation unit 112 outputs information regarding the result of the operation of the operation unit 112 by the occupant to the terminal control device 120. The terminal control device 120 causes the communication device 101 to transmit the information regarding the operation result input from the operation unit 112 to the vehicle 10. The information regarding the operation result includes information regarding whether or not to permit the execution of the proposed driving mode.

[0069] <User Request Receiving Unit> When information regarding the driving mode is transmitted to the information terminal 100, the user request receiving unit M17 waits for information regarding the operation result to be transmitted from the information terminal 100. When the communication device 60 receives information regarding the operation result from the information terminal 100, the user request receiving unit M17 analyzes the information to determine whether or not the execution of the proposed driving mode has been permitted by the occupant.

[0070] <Driving Mode Determination Unit> When the user request reception unit M17 determines that the occupant has authorized the execution of the proposed driving mode, the driving mode determination unit M19 decides to execute the proposed driving mode. For example, when the driving mode determination unit M19 determines to execute the first driving mode, it instructs the brake control device 71 to execute stationary braking control during vehicle braking. Furthermore, when the driving mode determination unit M19 determines to execute the second driving mode, it instructs the brake control device 71 to execute distribution adjustment control at the beginning of braking.

[0071] <Driving Mode Proposal Method> The driving mode proposal method will be described with reference to Figures 6, 7, and 8. Figure 6 illustrates a series of processes executed by the processing circuitry 81 of the driving mode proposal device 80 when the first driving mode is proposed to the occupant.

[0072] In step S11, the processing circuit 81 acquires vehicle information. In the next step S13, the processing circuit 81 acquires in-vehicle information. In the following step S15, the processing circuit 81 acquires outside-vehicle information.

[0073] Then, in step S17, the processing circuit 81 determines whether the prohibition condition is satisfied based on the outside-vehicle information acquired in step S15. If the processing circuit 81 determines that the prohibition condition is satisfied (S17: YES), the processing circuit 81 ends the series of processes shown in FIG. 6. In this case, the processing circuit 81 does not allow the occupant to select the first driving mode. On the other hand, if the processing circuit 81 determines that the prohibition condition is not satisfied (S17: NO), the processing circuit 81 proceeds to step S19.

[0074] In step S19, the processing circuit 81 determines whether the fatigue level estimated value FLE is equal to or greater than the fatigue level threshold FLEth. Specifically, the processing circuit 81 derives the fatigue level estimated value FLE based on the in-vehicle information acquired in step S13, etc. Then, the processing circuit 81 determines whether the derived fatigue level estimated value FLE is equal to or greater than the fatigue level threshold FLEth. If the fatigue level estimated value FLE is equal to or greater than the fatigue level threshold FLEth (S19: YES), the processing circuit 81 proceeds to step S25. On the other hand, if the fatigue level estimated value FLE is less than the fatigue level threshold FLEth (S19: NO), the processing circuit 81 proceeds to step S21.

[0075] In step S21, the processing circuit 81 determines whether or not the passenger has signs of motion sickness based on the in-vehicle information acquired in step S13, etc. If the processing circuit 81 determines that there are signs of motion sickness (S21: YES), the processing circuit 81 proceeds to step S25. On the other hand, if the processing circuit 81 determines that there are no signs of motion sickness (S21: NO), the processing circuit 81 proceeds to step S23. Note that if there is no passenger in the vehicle cabin, the processing circuit 81 determines that there are no signs of motion sickness in step S21.

[0076] In step S23, the processing circuit 81 acquires the consecutive number CNT1 of times the longitudinal acceleration fluctuation amount ΔGx when the vehicle 10 stops becomes equal to or greater than the fluctuation amount threshold ΔGxth. The processing circuit 81 then determines whether the consecutive number CNT1 is equal to or greater than a predetermined number CNT1th. If the consecutive number CNT1 is equal to or greater than the predetermined number CNT1th, the processing circuit 81 determines that the fluctuation amount ΔGx when the vehicle 10 stops due to the application of braking force associated with the driver's braking operation becomes equal to or greater than the fluctuation amount threshold ΔGxth. Therefore, if the consecutive number CNT1 is equal to or greater than the predetermined number CNT1th (S23: YES), the processing circuit 81 proceeds to step S25. On the other hand, if the consecutive number CNT1 is less than the predetermined number CNT1th (S23: NO), the processing circuit 81 terminates the series of processes shown in FIG. 6 . In this case, the processing circuit 81 does not prompt the occupant to select the first driving mode.

[0077] In step S25, the processing circuitry 81 selects a first driving mode from among the plurality of driving modes. In the following step S27, the processing circuitry 81 instructs the information terminal 100 to propose the first driving mode to the occupant. Specifically, the processing circuitry 81 causes the communication device 60 to transmit information about the first execution mode to the information terminal 100. Thereafter, the processing circuitry 81 ends the series of processes shown in FIG. 6 .

[0078] 6, steps S11, S13, and S15 correspond to an "acquisition step" in which the processing circuit 81, which is one of the on-board computers, acquires at least one of the in-vehicle information, the outside-vehicle information, and the vehicle information. Step S25 corresponds to a "selection step" in which the processing circuit 81 selects, from among a plurality of driving modes, a driving mode that corresponds to the information acquired in the acquisition step.

[0079] In this embodiment, the processes of steps S11, S13, and S15 are executed by the processing circuitry 81 functioning as the acquisition unit M11. The processes of steps S17, S19, S21, S23, and S25 are executed by the processing circuitry 81 functioning as the selection unit M13. Step S27 is executed by the processing circuitry 81 functioning as the instruction unit M15.

[0080] 7 illustrates a series of processes executed by the processing circuitry 81 of the driving mode suggestion device 80 when suggesting the second driving mode to the occupant. In step S41, the processing circuitry 81 acquires vehicle information. In the next step S43, the processing circuitry 81 acquires in-vehicle information. In the following step S45, the processing circuitry 81 acquires outside-vehicle information.

[0081] In step S47, the processing circuit 81 determines whether the prohibition condition is satisfied based on the outside-vehicle information acquired in step S45. If the processing circuit 81 determines that the prohibition condition is satisfied (S47: YES), the processing circuit 81 ends the series of processes shown in FIG. 7. In this case, the processing circuit 81 does not allow the occupant to select the second driving mode. On the other hand, if the processing circuit 81 determines that the prohibition condition is not satisfied (S47: NO), the processing circuit 81 proceeds to step S49.

[0082] In step S49, the processing circuit 81 determines whether the fatigue level estimated value FLE is equal to or greater than the fatigue level threshold value FLEth, as in step S19. If the fatigue level estimated value FLE is equal to or greater than the fatigue level threshold value FLEth (S49: YES), the processing circuit 81 proceeds to step S55. On the other hand, if the fatigue level estimated value FLE is less than the fatigue level threshold value FLEth (S49: NO), the processing circuit 81 proceeds to step S51.

[0083] In step S51, the processing circuit 81 determines whether the passenger has signs of motion sickness, similar to step S21. If the processing circuit 81 determines that the passenger has signs of motion sickness (S51: YES), the processing circuit 81 proceeds to step S55. On the other hand, if the processing circuit 81 determines that the passenger does not have signs of motion sickness (S51: NO), the processing circuit 81 proceeds to step S53.

[0084] In step S53, the processing circuit 81 acquires the number of consecutive occurrences CNT2 in which the increase rate dBPRq of the required braking force at the initial stage of braking is equal to or greater than the increase rate threshold dBPRqth. The processing circuit 81 then determines whether the number of consecutive occurrences CNT2 is equal to or greater than a predetermined number CNT2th. If the number of consecutive occurrences CNT2 is equal to or greater than the predetermined number CNT2th, the processing circuit 81 determines that the increase rate dBPRq is equal to or greater than the increase rate threshold dBPRqth at the initial stage of vehicle braking associated with the driver's braking operation. Therefore, if the number of consecutive occurrences CNT2 is equal to or greater than the predetermined number CNT2th (YES in S53), the processing circuit 81 proceeds to step S55. On the other hand, if the number of consecutive occurrences CNT2 is less than the predetermined number CNT2th (NO in S53), the processing circuit 81 terminates the series of processes shown in FIG. 7 . In this case, the processing circuit 81 does not prompt the occupant to select the second driving mode.

[0085] In step S55, the processing circuitry 81 selects a second driving mode from among the plurality of driving modes. In the following step S57, the processing circuitry 81 instructs the information terminal 100 to propose the second driving mode to the occupant. Specifically, the processing circuitry 81 causes the communication device 60 to transmit information about the second execution mode to the information terminal 100. Thereafter, the processing circuitry 81 ends the series of processes shown in FIG. 7 .

[0086] 7, steps S41, S43, and S45 correspond to an "acquisition step" in which the processing circuit 81, which is one of the on-board computers, acquires at least one of the in-vehicle information, the out-of-vehicle information, and the vehicle information. Step S55 corresponds to a "selection step" in which the processing circuit 81 selects, from among a plurality of driving modes, a driving mode that corresponds to the information acquired in the acquisition step.

[0087] In this embodiment, the processes of steps S41, S43, and S45 are executed by the processing circuitry 81 functioning as the acquisition unit M11. The processes of steps S47, S49, S51, S53, and S55 are executed by the processing circuitry 81 functioning as the selection unit M13. Step S57 is executed by the processing circuitry 81 functioning as the instruction unit M15.

[0088] 8 illustrates a series of processes when the information terminal 100 notifies the occupant of the driving mode selected by the driving mode suggestion device 80. In step S81, the terminal control device 120 of the information terminal 100 determines whether the communication device 101 has received information regarding the driving mode from the vehicle 10. If the terminal control device 120 determines that the communication device 101 has received the information (S81: YES), the process proceeds to step S83. On the other hand, if the terminal control device 120 determines that the communication device 101 has not received the information (S81: NO), the process illustrated in FIG. 8 is temporarily terminated.

[0089] In step S83, the terminal control device 120 proposes to the occupant the driving mode indicated by the information received from the vehicle 10. Specifically, the terminal control device 120 causes the display unit 111 to display a message proposing the driving mode.

[0090] In the next step S85, the terminal control device 120 determines whether an operation for determining whether or not to permit execution of the driving mode has been performed on the operation unit 112. If the terminal control device 120 determines that the operation has not yet been performed (S85: NO), it repeats the determination of step S85 until the operation is performed. On the other hand, if the terminal control device 120 determines that the operation has been performed (S85: YES), it proceeds to step S87.

[0091] In step S87, the terminal control device 120 causes the communication device 101 to transmit information regarding the result of the occupant's operation of the operation unit 112 to the vehicle 10. That is, the terminal control device 120 instructs the communication device 101 to transmit information regarding whether or not the occupant has permitted the execution of the above-mentioned driving mode to the vehicle 10. Thereafter, the terminal control device 120 temporarily ends the series of processes shown in FIG.

[0092] In the series of processes shown in FIG. 8 , step S85 corresponds to a "proposal step" in which the information terminal 100 proposes the driving mode selected in the selection step to the occupant. <Actions and Effects of the Present Embodiment> The processing circuit 81 of the driving mode proposal device 80 acquires interior information, exterior information, and vehicle information of the vehicle 10. The processing circuit 81 selects a driving mode from multiple driving modes according to the acquired information. At this time, the processing circuit 81 can select a driving mode that does not cause the occupant to feel uncomfortable with the behavior of the vehicle 10. Then, the processing circuit 81 instructs the information terminal 100 to propose the selected driving mode to the occupant. Specifically, the processing circuit 81 instructs the communication device 60 to transmit information regarding the selected driving mode to the information terminal 100.

[0093] Therefore, the driving mode suggestion device 80 can contribute to suggesting to the occupant a driving mode that will not cause the occupant to feel uncomfortable with the behavior of the vehicle 10. When the terminal control device 120 of the information terminal 100 receives information related to the driving mode from the vehicle 10, it suggests the driving mode to the occupant. For example, the terminal control device 120 displays a message suggesting a driving mode on the display unit 111.

[0094] When the occupant sees the message on the display unit 111, the occupant operates the operation unit 112. If the occupant operates the operation unit 112 to permit execution of the driving mode, the terminal control device 120 causes the vehicle 10 to transmit a message indicating that execution of the driving mode is permitted. On the other hand, if the occupant operates the operation unit 112 to prohibit execution of the driving mode, the terminal control device 120 causes the vehicle 10 to transmit a message indicating that execution of the driving mode is not permitted.

[0095] The processing circuitry 81 of the driving mode suggestion device 80 acquires, from the communication device 60, information transmitted from the information terminal 100 to the vehicle 10. If the occupant permits the execution of the driving mode, the processing circuitry 81 transmits the execution of the driving mode selected by the processing circuitry 81 to the various control devices 71, 73, and 75. On the other hand, if the occupant does not permit the execution of the driving mode, the processing circuitry 81 does not transmit the execution of the driving mode selected by the processing circuitry 81 to the various control devices 71, 73, and 75. Therefore, the control system 70 can prevent the vehicle 10 from driving based on a driving mode that makes the occupant feel uncomfortable with the behavior of the vehicle 10.

[0096] The present embodiment can further provide the following advantages. (1) The processing circuitry 81 of the driving mode suggestion device 80 acquires information related to the driver's vehicle operation as vehicle information. Therefore, the processing circuitry 81 can select a driving mode from among a plurality of driving modes that corresponds to the driver's driving skill, which can be estimated from the information related to the driver's vehicle operation. This allows the driving mode suggestion device 80 to have the information terminal 100 suggest to the occupant a driving mode that corresponds to the driver's driving skill.

[0097] For example, as shown in Figure 4, when the vehicle is braked in response to the driver's braking operation, if the fluctuation amount ΔGx of the longitudinal acceleration when the vehicle is stopped becomes equal to or greater than the fluctuation amount threshold value ΔGxth, the driving mode suggestion device 80 can have the information terminal 100 suggest to the occupant that braking control when the vehicle is stopped is performed when the vehicle is braked in response to the driver's braking operation.

[0098] For example, as shown in Figure 5, if the increase rate dBPRq of the required braking force becomes equal to or greater than the increase rate threshold dBPRq at the beginning of vehicle braking associated with the driver's braking operation, the driving mode suggestion device 80 can have the information terminal 100 suggest to the occupant that distribution adjustment control be performed at the beginning of vehicle braking associated with the driver's braking operation.

[0099] (2) When the driver's level of fatigue from driving increases, the driver may become unable to perform delicate vehicle operation. Therefore, the processing circuit 81 of the driving mode suggestion device 80 acquires information related to the driver's level of fatigue as in-vehicle information. Then, when the driver's level of fatigue estimated from the information related to the driver's level of fatigue is equal to or greater than a threshold, the processing circuit 81 can make the information terminal 100 suggest to the occupant that a stop-time braking control be performed when braking the vehicle in response to the driver's braking operation, and that a distribution adjustment control be performed at the initial stage of vehicle braking in response to the driver's braking operation.

[0100] If the occupant accepts such a suggestion, the control system 70 can cause the vehicle 10 to drive in a manner that suppresses sudden changes in the behavior of the vehicle 10, even if the driver is highly fatigued from driving.

[0101] (3) The processing circuit 81 of the driving mode suggestion device 80 acquires information about passengers as in-vehicle information. Then, the processing circuit 81 determines a driving mode to suggest to the occupant based on the information about the passengers. This allows the driving mode suggestion device 80 to suggest to the occupant, via the information terminal 100, a driving mode that is appropriate for the presence or absence of a passenger and the state of the passenger.

[0102] For example, the processing circuitry 81 determines whether the passenger has signs of motion sickness based on the acquired information about the passenger. If the processing circuitry 81 determines that the passenger has signs of motion sickness, it can cause the information terminal 100 to suggest to the passenger that a stop braking control be performed when braking the vehicle in response to a braking operation by the driver, and that distribution adjustment control be performed at the beginning of vehicle braking in response to a braking operation by the driver.

[0103] If the driver accepts such a suggestion, the control system 70 can cause the vehicle 10 to drive in a manner that prevents the passenger's level of motion sickness from further increasing. <Modifications> The above embodiment can be modified as follows. The above embodiment and the following modifications can be combined with each other to the extent that they are not technically inconsistent.

[0104] - When the processing circuit 81 (i.e., the selection unit) of the driving mode suggestion device 80 determines that there is a passenger in the vehicle, it may select at least one of the first driving mode and the second driving mode, regardless of whether the passenger shows signs of motion sickness.

[0105] The processing circuit 81 (i.e., the selection unit) of the driving mode suggestion device 80 may select at least one of the first driving mode and the second driving mode when it is estimated that the passenger is asleep.

[0106] The processing circuit 81 (i.e., the selection unit) of the driving mode suggestion device 80 may determine the driving mode to suggest to the occupant without taking into account the presence or absence of a passenger or the state of the passenger. The processing circuit 81 (i.e., the selection unit) of the driving mode suggestion device 80 may determine the driving mode to suggest to the occupant from among a plurality of driving modes without taking into account the driver's fatigue level. In this case, if it is estimated that the driver's fatigue level is high, the processing circuit 81 may suggest to the driver that they stop the vehicle and take a rest.

[0107] When information regarding the presence or absence of a preceding vehicle can be acquired as external vehicle information, the processing circuit 81 (i.e., the selection unit) of the driving mode suggestion device 80 may select a driving mode based on the presence or absence of a preceding vehicle. For example, the processing circuit 81 may not select the first driving mode or the second driving mode when a preceding vehicle is present. In other words, the processing circuit 81 may select the first driving mode or the second driving mode under the condition that at least one of the following is true: there is no preceding vehicle; or the inter-vehicle distance between the preceding vehicle and the vehicle 10 (host vehicle) is equal to or greater than a threshold.

[0108] The multiple driving modes do not have to include the first driving mode. The multiple driving modes do not have to include the second driving mode. The multiple driving modes may include driving modes other than the driving mode that improves the ride comfort of the occupants by adjusting the braking force. For example, the other driving modes may include a driving mode that suppresses a sudden increase in acceleration of the vehicle 10 when starting. Furthermore, for example, the other driving modes may include a driving mode that suppresses a sudden change in the yaw rate Yr or lateral acceleration Gy of the vehicle 10 when the vehicle 10 turns.

[0109] The processing circuit 81 (i.e., the acquisition unit) of the driving mode suggestion device 80 does not need to acquire at least one of the outside-vehicle information and the vehicle information as long as it acquires inside-vehicle information. The processing circuit 81 (i.e., the acquisition unit) of the driving mode suggestion device 80 does not need to acquire at least one of the inside-vehicle information and the vehicle information as long as it acquires outside-vehicle information.

[0110] The processing circuit 81 (i.e., the acquisition unit) of the driving mode suggestion device 80 does not need to acquire at least one of the in-vehicle information and the outside-vehicle information as long as it acquires vehicle information. In the above embodiment, the information terminal 100 owned by the occupant is described as functioning as the suggestion device. However, a device other than the information terminal 100 may also function as the suggestion device. For example, an in-vehicle navigation device may also function as the suggestion device.

[0111] In the above embodiment, the suggestion device makes suggestions by displaying on a screen. However, as long as it is possible to suggest driving modes to the occupant, it may be possible to suggest driving modes to the occupant by a method other than displaying on a screen. For example, the suggestion device may include a speaker that suggests driving modes by voice. In this case, the occupant may input voice into a microphone to inform the driving mode suggestion device whether or not to accept the suggestion.

[0112] The processing circuitry 81 of the driving mode suggestion device 80 may be configured as a circuit including one or more processors operating according to a computer program, one or more dedicated hardware circuits such as dedicated hardware that executes at least some of the various processes, or a combination thereof. Examples of dedicated hardware include an application-specific integrated circuit (ASIC). The processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., storage medium, includes any available medium accessible by a general-purpose or dedicated computer.

[0113] <Other Technical Ideas> The following describes technical ideas that can be understood from the above-described embodiment and modified examples. [Supplementary Note 1] It is preferable that the plurality of driving modes include a driving mode that implements distribution adjustment control to adjust the distribution of braking force so as to reduce the rate of change in the pitch angle of the vehicle when braking of the vehicle starts, the information related to the vehicle operation of the driver of the vehicle includes information related to the rate of increase in a braking force request value during vehicle braking associated with the braking operation of the driver, and the instructing unit instructs the suggestion device to suggest to the occupant a driving mode in which the distribution adjustment control is implemented when the rate of increase in the braking force request value during vehicle braking associated with the driver's vehicle braking becomes equal to or greater than a threshold.

[0114] [Appendix 2] A driving mode suggestion method for suggesting a driving mode to an occupant of a vehicle in which a plurality of driving modes are prepared to improve the riding comfort of the occupant of the vehicle, the driving mode suggestion method including: an acquisition step in which an on-board computer acquires at least one of information on the inside of the vehicle, information on the outside of the vehicle, and vehicle information; a selection step in which the computer selects, from the plurality of driving modes, a driving mode that corresponds to the information acquired in the acquisition step; and a proposal step in which a proposal device proposes the driving mode selected in the selection step to the occupant.

[0115] It should be noted that the expression "at least one" used in this specification means "one or more" of the desired options. As an example, the expression "at least one" used in this specification means "only one option" or "both of two options" if the number of options is two. As another example, the expression "at least one" used in this specification means "only one option" or "any combination of two or more options" if the number of options is three or more.

Claims

1. The present invention is applied to a vehicle in which a plurality of driving modes are provided to improve the riding comfort of vehicle occupants, and includes an acquisition unit that acquires at least one of in-vehicle information, out-of-vehicle information, and vehicle information of the vehicle, and an instruction unit that instructs a proposal device to propose to the occupant a driving mode corresponding to the information acquired by the acquisition unit among the plurality of driving modes. A driving mode proposal device comprising the above.

2. The acquisition unit acquires information regarding the vehicle operation of the driver of the vehicle as the vehicle information, and the instruction unit instructs the proposal device to propose to the occupant a driving mode corresponding to the driving skill of the driver inferred from the information regarding the vehicle operation of the driver among the plurality of driving modes. The driving mode proposal device according to claim 1.

3. The plurality of driving modes include a driving mode in which when applying a braking force to the vehicle to stop it, the braking force applied to the vehicle is reduced to a predetermined braking force and then the vehicle body speed of the vehicle is set to 0 (zero) to perform a braking control at the time of stopping. The acquisition unit acquires the longitudinal and lateral accelerations of the vehicle as the vehicle information, and the instruction unit instructs the proposal device to propose to the occupant the driving mode that performs the braking control at the time of stopping when the amount of change in the longitudinal and lateral accelerations when the vehicle stops due to the application of the braking force accompanying the braking operation of the driver of the vehicle is equal to or greater than a threshold value. The driving mode proposal device according to claim 1.

4. The plurality of driving modes include a driving mode in which when applying a braking force to the vehicle to stop it, the braking force applied to the vehicle is reduced to a predetermined braking force and then the vehicle body speed of the vehicle is set to 0 (zero) to perform a braking control at the time of stopping. The acquisition unit acquires information related to the fatigue level of the driver of the vehicle as the in-vehicle information, and the instruction unit instructs the proposal device to propose to the occupant the driving mode that performs the braking control at the time of stopping when the fatigue level of the driver inferred from the information related to the fatigue level of the driver is equal to or greater than a threshold value. The driving mode proposal device according to claim 1.

5. The plurality of driving modes include a driving mode that, when applying a braking force to the vehicle to stop it, performs a braking control at the time of stopping in which the braking force applied to the vehicle is decreased to a predetermined braking force and then the vehicle body speed of the vehicle is set to 0 (zero). The acquisition unit acquires, as the in-vehicle information, information regarding a passenger who is a passenger other than the driver of the vehicle. The instruction unit determines whether or not to propose to the passenger the driving mode that performs the braking control at the time of stopping based on the information regarding the passenger. The driving mode proposal device according to claim 1.

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