Vehicle control method and vehicle control device

Abstract

To provide a vehicle control method and a vehicle control device capable of suppressing motion sickness by suppressing a behavior change of a vehicle as much as possible in consideration of the latest index value.SOLUTION: The vehicle control method includes calculating, based on a behavior of the vehicle, an index value obtained by quantifying a degree of causing motion sickness of an occupant of the vehicle, calculating an allowable upper limit of a front-rear direction acceleration of the vehicle based on the front-rear direction acceleration of the vehicle when the index value is calculated, a lateral acceleration of the vehicle, and the index value, selecting a minimum allowable upper limit from among past allowable upper limits calculated during a period from a current time to a predetermined time ago, and limiting a braking / driving force of the vehicle such that the front-rear direction acceleration of the vehicle is within the minimum allowable upper limit.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a vehicle control method and a vehicle control device. [Background technology]

[0002] BACKGROUND ART A control device that controls a vehicle so as to suppress car sickness in a passenger is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-59274 Summary of the Invention [Problem to be solved by the invention]

[0004] In the vehicle control device described in Patent Document 1, when a vehicle occupant turns on a car sickness switch, a correlation value (index value) between the vehicle state and the occurrence of car sickness in the occupant is calculated, and car sickness suppression automatic driving is performed based on this correlation value. For this reason, it is not possible to suppress car sickness by taking into account the most recent index value and minimizing changes in vehicle behavior as much as possible.

[0005] An object of the present invention is to provide a vehicle control method and vehicle control device that can take into account the most recent index value, minimize changes in vehicle behavior, and suppress car sickness. [Means for solving the problem]

[0006] One aspect of the present invention calculates an allowable upper limit for the vehicle's longitudinal acceleration based on an index value that quantifies the degree to which the vehicle occupants will become carsick, the vehicle's longitudinal acceleration, and the vehicle's lateral acceleration, selects the smallest allowable upper limit from among past allowable upper limits calculated between the present and a predetermined time ago, and limits the vehicle's braking and driving forces so that the longitudinal acceleration is within the smallest allowable upper limit.

[0007] According to the above aspect, it is possible to suppress car sickness by taking into consideration the most recent index value and minimizing changes in the vehicle's behavior as much as possible. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing a schematic configuration of a vehicle according to an embodiment; [Figure 2] FIG. 2 is a control block diagram of a controller according to the embodiment. [Figure 3] 4 is a flowchart of control executed by a controller. [Figure 4] 10 is a flowchart showing a method for setting an allowable upper limit value of longitudinal acceleration. [Figure 5] FIG. 10 is a diagram illustrating the relationship between the index value, lateral acceleration, and longitudinal acceleration. [Figure 6] FIG. 10 is a diagram showing the relationship between the time between the peaks on the positive and negative sides of acceleration and the lateral acceleration and the longitudinal acceleration. [Figure 7] 10 is a diagram showing the relationship between the index value and the longitudinal acceleration over time and the past allowable upper limit value. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following, the driver's operation to request braking / driving force using a braking / driving force request operation means such as an accelerator pedal will be referred to as the "accelerator operation," and the amount of operation will be referred to as the "accelerator operation amount." Also, the driver's request for braking force using a braking force request operation means such as a brake pedal will be referred to as the "brake operation," and the amount of operation will be referred to as the "brake operation amount." In addition, braking / driving force refers to driving force and braking force. Both driving force and braking force are physical quantities that take positive values, but in the program that executes control, braking force is treated as a negative driving force, and driving force and braking force are expressed by positive and negative values ​​of braking / driving force, so braking force is sometimes described as a negative value.

[0010] FIG. 1 is a diagram showing a schematic configuration of a vehicle 1. As shown in FIG. Vehicle 1 is an electric vehicle that runs using an electric motor 23 as a drive source. Vehicle 1 is equipped with a braking / driving force generating device 2, a control mode selecting device 3, an alarm device 4, a navigation device 5, a control device 6, and sensors 7A, 7B, 7C, 7D, 7E, 7F, and 7G.

[0011] The braking / driving force generation device 2 includes an inverter 21, a battery 22, an electric motor 23 as a drive source, a reducer 24, wheels 25, and a friction braking mechanism 26. Based on a command input from the control device 6, the inverter 21 converts the direct current input from the battery 22 into alternating current and outputs it to the electric motor 23. Based on a command input from the control device 6, the inverter 21 also converts the alternating current input from the electric motor 23 into direct current and inputs it to the battery 22. The reducer 24 includes a transmission 24A and a differential gear 24B, and transmits the output of the electric motor 23 to the wheels 25 after reducing the speed at a predetermined gear ratio based on the control of the control device 6. The friction braking mechanism 26 includes, for example, a hydraulic or electric disc brake, and generates a braking force on the wheel 25 by friction force.

[0012] The control mode selection device 3 allows the occupants of the vehicle 1 to select whether or not to limit the braking / driving force of the vehicle 1. The control mode selection device 3 is composed of switches, dials, buttons, touch panels, etc., and allows the selection of the control mode of the control device 6. The control modes include, for example, a first control mode that limits the braking / driving force of the vehicle 1 based on an index value that quantifies the degree to which the occupants of the vehicle 1 become carsick, and a second control mode that does not limit the braking / driving force of the first control mode.

[0013] The notification device 4 includes a display 41 and a speaker 42. The notification device 4 displays images and text on the display 41 and outputs sounds from the speaker 42 in accordance with instructions from the navigation device 5 and the control device 6.

[0014] The navigation device 5 is equipped with a position sensor 51 such as a GNSS (Global Navigation Satellite System). The navigation device 5 acquires map information and driving environment information within a predetermined distance around the vehicle, and displays the map information and driving environment information on the display 41 and outputs them as audio from the speaker 42. For example, the navigation device 5 displays the current position of the vehicle 1 detected by the position sensor 51 and a driving route to a destination or an intermediate destination on a map displayed on the display 41, and provides driving route guidance by audio output from the speaker 42. The driving environment information includes, for example, the speed of the vehicle 1 (hereinafter referred to as vehicle speed), traffic volume and congestion information on the road on which the vehicle 1 is traveling, weather conditions, and road conditions. The road conditions include the degree of inclination of the road and unevenness of the road surface.

[0015] The control device 6 includes an accelerator position sensor 7A as an accelerator operation amount sensor, a vehicle speed sensor 7C, an acceleration sensor 7D, an angular velocity sensor 7E, a steering angle sensor 7G, and a controller 8.

[0016] The accelerator position sensor 7A detects the amount of accelerator operation of the vehicle 1. The accelerator position sensor 7A is configured, for example, by a pedal stroke sensor, and detects the amount of operation of an accelerator pedal 71, which serves as driving force request operation means, as the amount of accelerator operation.

[0017] The brake sensor 7B detects the amount of braking operation of the vehicle 1. The brake sensor 7B is configured by, for example, a pedal stroke sensor, and detects the amount of operation of a brake pedal 72, which serves as braking force request operation means, as the amount of braking operation.

[0018] The vehicle speed sensor 7C is configured by, for example, a rotation speed sensor of the wheels 25, and detects the speed of the vehicle 1 (hereinafter referred to as vehicle speed).

[0019] The acceleration sensor 7D is mounted on the vehicle 1 and detects the acceleration of the vehicle 1 in the longitudinal and lateral directions.

[0020] The angular velocity sensor 7E is mounted on the vehicle 1 and detects the angular velocity of the vehicle 1.

[0021] The surrounding sensor 7F is a sensor that detects objects around the vehicle 1, and includes, for example, a camera or a radar sensor. Examples of objects to be detected include other vehicles around the vehicle 1, marked lines on the road surface, and obstacles on the road. Examples of marked lines on the road surface include dividing lines that separate lanes, stop lines, pedestrian crossings, and bicycle crossing zones. Obstacles are anything that hinders the travel of the vehicle 1, and include objects installed on the road as well as pedestrians and bicycles walking on the road.

[0022] The steering angle sensor 7G detects the steering angle of the vehicle 1.

[0023] Controller 8 controls the braking / driving force generated by electric motor 23 and the braking force generated by friction braking mechanism 26 based on the accelerator operation amount, vehicle speed, etc. Controller 8 is configured by, for example, a microcomputer equipped with a calculation unit such as a CPU (Central Processing Unit) and a GPU (Central Graphics Processing Unit), a storage unit 81 such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and an input / output unit such as an input / output interface. To controller 8, control mode selection device 3, notification device 4, accelerator position sensor 7A, brake sensor 7B, vehicle speed sensor 7C, acceleration sensor 7D, angular velocity sensor 7E, surroundings sensor 7F, steering angle sensor 7G, inverter 21, and friction braking mechanism 26 are electrically or communicatively connected.

[0024] FIG. 2 is a control block diagram of the controller 8. As shown in FIG. 2, the controller 8 includes a memory unit 81, a braking / driving force setting unit 82, an index value calculation unit 83, a braking / driving force restriction necessity determination unit 84, an acceleration allowable upper limit value calculation unit 85, an allowable upper limit value selection unit 86, a braking / driving force restriction unit 87, and an alarm unit 88.

[0025] The memory unit 81 stores a computer program for causing the controller 8 to function, various maps used for control, various parameter values, etc. The maps stored in the memory unit 81 include, for example, a map that defines the relationship between accelerator operation amount, vehicle speed, and braking / driving force, and a map that defines the relationship between an index value, lateral acceleration, and longitudinal acceleration. The parameter values ​​stored in the memory unit 81 include, for example, a maximum allowable value used when changing the minimum allowable upper limit value according to vehicle speed, and various threshold values.

[0026] Braking / driving force setting unit 82 sets the braking / driving forces to be generated by electric motor 23. Braking / driving force setting unit 82 outputs commands to inverter 21 to output the set braking / driving forces, and causes electric motor 23 to drive or regenerate in accordance with the commands. In the present embodiment, braking / driving force setting unit 82 sets the braking / driving forces requested by the driver through operation of accelerator pedal 71, based on the accelerator operation amount and vehicle speed.

[0027] The index value calculation unit 83 calculates an index value that quantifies the degree to which an occupant of the vehicle 1 will experience car sickness, based on the behavior of the vehicle 1. The index value indicates the degree of concern about car sickness and can be calculated using a known method, such as the SVC (Subjective Vertical Conflict Theory) model. The SVC model calculates the error between the subjective sense of motion perceived by the occupant of the vehicle 1 from the acceleration occurring in the head and the estimated value of the sense of motion based on the occupant's internal model, and calculates the degree of concern about car sickness by accumulating this discrepancy over time (see Fujisawa, Wada, Konno, and Doi (2012), "Analysis of Driver's Head Position Control Strategy and Its Application to an Attitude Control Device," Transactions of the Society of Instrument and Control Engineers, Vol. 48, No. 1, pp. 60-66). In this embodiment, the index value calculation unit 83 calculates the index value of the following equation (1) calculated by the SVC model, based on the longitudinal and lateral accelerations of the vehicle 1 and the angular velocity of the vehicle 1. Here, Δv is the error between the subjective sense of movement and the estimated value of the sense of movement based on the occupant's internal model, and b is a parameter constant that represents the response sensitivity of the Hill function.

[0028] Index value = (||Δv||÷b) 2 ÷{1+(||Δv||÷b) 2} …(1)

[0029] Braking / driving force restriction necessity determining section 84 determines, based on the input from control mode selection device 3, whether or not restriction of braking / driving force is necessary.

[0030] The allowable acceleration upper limit value calculation unit 85 calculates an allowable upper limit value of the longitudinal acceleration of the vehicle 1 based on the longitudinal acceleration of the vehicle 1, the lateral acceleration of the vehicle 1, and the index value when the index value is calculated. The allowable acceleration upper limit value calculation unit 85 stores the calculated allowable upper limit value in the memory unit 81.

[0031] The allowable upper limit value selection unit 86 selects the smallest allowable upper limit value from among past allowable upper limit values ​​calculated from the present until a predetermined time ago. The allowable upper limit value selection unit 86 also changes the selected smallest allowable upper limit value as necessary. The predetermined time is set taking into consideration the effect that the frequency of the longitudinal acceleration has on the index value. The sensitivity of the index value to acceleration fluctuations varies depending on the acceleration frequency; the index value increases as the frequency decreases, but once the frequency drops to a certain level, the index value begins to decrease. Therefore, when selecting the smallest allowable upper limit value, it is sufficient to set the predetermined time so that it includes the frequency period at which the index value is maximized.

[0032] Based on the braking / driving force set by braking / driving force setting unit 82, the determination result by braking / driving force limitation necessity determination unit 84, and the selected minimum allowable upper limit, braking / driving force limiting unit 87 limits the braking / driving force of vehicle 1 so that the longitudinal acceleration of vehicle 1 falls within the minimum allowable upper limit. Braking / driving force limiting unit 87 outputs a command to inverter 21 to output a final braking / driving force, and causes electric motor 23 to drive or regenerate in accordance with the command. If electric motor 23 alone is unable to generate the set braking force, braking / driving force limiting unit 87 outputs a command to friction braking mechanism 26 to supplement the braking force produced by electric motor 23, and causes friction braking mechanism 26 to perform braking operation in accordance with the command.

[0033] When limiting the braking / driving forces of the vehicle 1 so that the longitudinal acceleration of the vehicle 1 is within the minimum allowable upper limit, the notification unit 88 notifies the occupants that the braking / driving forces will be limited. In the present embodiment, the notification unit 88 notifies the occupants that the braking / driving forces will be limited visually by the display 41 and audibly by the speaker 42.

[0034] 3 and 4 are flowcharts of the braking / driving force control executed by controller 8. The control routine shown in the flowchart is pre-programmed, and this program is installed in controller 8. In accordance with the program, controller 8 repeatedly executes the following control routine at an operation cycle of, for example, about 10 milliseconds.

[0035] In step S1 of FIG. 3, the controller 8 acquires the outputs of the control mode selection device 3, the navigation device 5, and the sensors 7A, 7B, 7C, 7D, 7E, 7F, and 7G, i.e., the control mode, driving environment information, accelerator operation amount, brake operation amount, vehicle speed, acceleration of the vehicle 1, angular velocity, surrounding detection conditions, and steering angle.

[0036] In step S2, braking / driving force setting unit 82 references, for example, a map that defines the relationship between accelerator operation amount and vehicle speed and braking / driving force, and sets braking / driving force based on accelerator operation amount and vehicle speed.

[0037] In step S3, braking / driving force limitation necessity determination unit 84 determines whether the first control mode, which limits the braking / driving forces, has been selected. If it is determined in step S3 that the first control mode has been selected, the process proceeds to step S4. If it is not determined in step S3 that the first control mode has been selected, in step S9, braking / driving force limiter 87 outputs commands to electric motor 23 and friction braking mechanism 26 to output set braking / driving forces without limiting the braking / driving forces, and then the process returns to step S1.

[0038] In step S4, the index value calculation unit 83 calculates an index value that quantifies the degree of car sickness based on the behavior of the vehicle 1. In this embodiment, the index value calculation unit 83 calculates the index value based on the longitudinal and lateral accelerations of the vehicle 1 and the angular velocity of the vehicle 1.

[0039] In step S5, braking / driving force limitation necessity determination unit 84 determines whether the vehicle speed is equal to or greater than the first speed threshold. If it is determined in step S5 that the vehicle speed is equal to or greater than the first speed threshold, the process proceeds to step S6, and if not, the process returns to step S1 via step S9.

[0040] In step S6, the allowable upper acceleration limit calculation unit 85 and the allowable upper limit selection unit 86 calculate the allowable upper limit of the longitudinal acceleration of the vehicle 1. The method for calculating the allowable upper limit of the longitudinal acceleration will be described later with reference to FIG.

[0041] In step S7, braking / driving force limiting unit 87 limits the braking / driving forces so that the longitudinal acceleration of vehicle 1 falls within the allowable upper limit. For example, braking / driving force limiting unit 87 limits the braking / driving forces so that the acceleration of vehicle 1 falls within the allowable upper limit, based on the difference between the longitudinal acceleration of vehicle 1 and the allowable upper limit, vehicle specifications such as the weight of vehicle 1 and the specifications of wheels 25, and vehicle characteristics such as the running resistance of vehicle 1. Braking / driving force limiting unit 87 outputs commands to electric motor 23 and friction braking mechanism 26 to output the limited braking / driving forces.

[0042] In step S8, the notification unit 88 notifies the occupant by displaying on the display 41 or outputting a sound from the speaker 42 that the braking / driving force will be limited.

[0043] The flowchart for setting the allowable upper limit of acceleration shown in FIG. 4 will be described below with reference to FIGS.

[0044] In step S61 of Fig. 4, the allowable acceleration upper limit calculation unit 85 calculates the allowable upper limit of the longitudinal acceleration of the vehicle 1 based on the longitudinal acceleration of the vehicle 1, the lateral acceleration of the vehicle 1, and the index value. Furthermore, each time the allowable acceleration upper limit calculation unit 85 calculates the allowable upper limit of the longitudinal acceleration, it stores the calculated allowable upper limit in the memory unit 81. In this embodiment, the allowable acceleration upper limit calculation unit 85 calculates the allowable upper limit of the longitudinal acceleration using the map shown in Fig. 5. For example, in Fig. 5, if the index value is S1 and the lateral acceleration of the vehicle 1 is AY1, the allowable upper limit of the longitudinal acceleration is AL2.

[0045] Here, the sensitivity of the index value to acceleration fluctuations of the vehicle 1 varies depending on the time between the positive peak and the negative peak of the acceleration (hereinafter referred to as the peak-to-peak time of the acceleration), i.e., the frequency of the acceleration. For this reason, the map shown in FIG. 5 is stored in the memory unit 81 for each peak-to-peak time of the acceleration. For example, FIG. 6 shows the relationship between the lateral acceleration when the index value is zero and the allowable longitudinal acceleration. The LY line in FIG. 6 corresponds to the LY line in FIG. 5.

[0046] In step S62 of FIG. 4, the allowable upper limit value selection unit 86 selects the smallest allowable upper limit value from among the past allowable upper limit values ​​calculated from the present until a predetermined time ago.

[0047] FIG. 7 is a diagram showing the relationship between the index value and the longitudinal acceleration of the vehicle 1 over time and past allowable upper limits. FIG. 7 illustrates examples of acceleration peak-to-peak times PD1 and PD2. FIG. 7 also shows allowable upper limits at time points t-1, t-2, t-3, and t-4, in order from closest to the current time t, as allowable upper limits up to a predetermined time ago. In this case, the allowable upper limit value selection unit 86 selects the allowable upper limit value at time point t-3 because the allowable upper limit value at time point t-3 is the smallest. Note that the acceleration peak-to-peak time used in calculating the allowable upper limit value may be, for example, the most recent one, or the average of multiple most recent ones.

[0048] 4, the allowable upper limit selection unit 86 determines whether the selected minimum allowable upper limit is equal to or greater than the threshold value. If it is determined in step S63 that the minimum allowable upper limit is not equal to or greater than the threshold value, the allowable upper limit selection unit 86 sets the threshold value to the minimum allowable upper limit in step S67. On the other hand, if it is determined in step S63 that the minimum allowable upper limit is equal to or greater than the threshold value, the process proceeds to step S64.

[0049] In step S64, braking / driving force limitation necessity determination unit 84 determines whether the vehicle speed is equal to or greater than a second speed threshold that is greater than the first speed threshold. If it is determined in step S64 that the vehicle speed is equal to or greater than the second speed threshold, then in step S65, allowable upper limit value selection unit 86 sets the selected minimum allowable upper limit value as the minimum allowable upper limit value.

[0050] On the other hand, if it is determined in step S64 that the vehicle speed is not equal to or greater than the second speed threshold, the process proceeds to step S66. In this embodiment, in step S66, the allowable upper limit value selection unit 86 changes the selected minimum allowable upper limit value according to the vehicle speed using the following equation (2), thereby transitioning from a state in which the braking / driving forces are not limited to a state in which the braking / driving forces are gradually limited based on the vehicle speed. The maximum allowable value is the maximum value of the longitudinal acceleration allowed when limiting the braking / driving forces, and is a fixed value stored in the memory unit 81. The speed-dependent coefficient is zero when the vehicle speed is the first speed threshold, increases as the vehicle speed increases, and is a value of 1 when the vehicle speed is the second speed threshold.

[0051] Minimum allowable upper limit value = Maximum allowable value - (Maximum allowable value - Selected minimum allowable upper limit value) x Speed ​​dependent coefficient ... (2)

[0052] According to the above-described embodiment, the allowable upper limit value of the longitudinal acceleration of vehicle 1 is calculated based on the longitudinal acceleration of vehicle 1, the lateral acceleration of vehicle 1, and the index value, and the smallest allowable upper limit value is selected from the past allowable upper limits calculated between the present and a predetermined time ago, and the braking / driving force of vehicle 1 is restricted so that the longitudinal acceleration is within the smallest allowable upper limit value. Therefore, by taking into account the most recent index value, changes in the behavior of vehicle 1 can be minimized as much as possible, thereby suppressing car sickness.

[0053] As described above, the best configurations, methods, and the like for implementing the present invention have been disclosed in the above description, but the present invention is not limited thereto. That is, although the present invention has been particularly illustrated and described mainly with reference to specific embodiments, those skilled in the art can make various modifications to the above-described embodiments in terms of shape, material, quantity, and other detailed configurations without departing from the scope of the technical idea and purpose of the present invention. Furthermore, the above-disclosed descriptions limiting the shape, material, and the like are provided as examples to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, descriptions using names of components that are free from some or all of the limitations on shape, material, and the like are included in the present invention.

[0054] The vehicle 1 may be a so-called series hybrid vehicle or a parallel hybrid vehicle. That is, the braking / driving force generation device 2 may be provided with an engine, and the engine may drive a generator to supply power to the electric motor 23, thereby driving the wheels 25 with the electric motor 23, or the wheels 25 may be driven by the electric motor 23 and the engine. The vehicle 1 may be an engine-driven vehicle that includes an engine instead of the inverter 21 and the electric motor 23 and runs using the engine as the sole driving source.

[0055] In the control device 6, the braking / driving force request operation means is configured as accelerator pedal 71, the braking force request operation means is configured as brake pedal 72, the accelerator operation amount sensor is configured as accelerator position sensor 7A, and the brake operation amount sensor is configured as brake sensor 7B, but other configurations are also possible. For example, the braking / driving force request operation means and the braking force request operation means may be configured as operation levers, operation dials, etc., and the accelerator operation amount sensor and the brake operation amount sensor may be configured as sensors such as stroke sensors and potentiometers that detect the amounts of operation of these.

[0056] The notification device 4 may be provided with a vibration device built into the seat of the vehicle 1, for example, and may notify the passenger by making the passenger feel the vibration.

[0057] The navigation device 5 may, for example, acquire map information recorded on a recording medium installed in the vehicle 1 from the recording medium, or may acquire map information by communicating with a data server on which the map information is stored via a communication line such as the Internet.

[0058] The vehicle speed sensor 7C is not particularly limited, and may be, for example, a ground speed sensor.

[0059] The index value calculation unit 83 may calculate the index value using a method other than the SVC model.

[0060] Braking / driving force restriction necessity determining section 84 may determine whether or not to relax the restriction on the braking / driving force, in addition to determining whether or not restriction on the braking / driving force is necessary.

[0061] Braking / driving force limitation necessity determination unit 84 may determine that limitation of the braking force is not necessary when there is a request to decelerate vehicle 1. As a result, when there is a request to decelerate vehicle 1, braking / driving force limitation unit 87 will not limit the braking force. The presence or absence of a deceleration request can be determined, for example, by whether the amount of brake operation or the rate of change in the amount of brake operation exceeds a threshold value.

[0062] Braking / driving force limitation necessity determination unit 84 may determine whether or not braking / driving force limitation is necessary based on the conditions around vehicle 1. For example, braking / driving force limitation necessity determination unit 84 may approve braking force limitation when the output of surrounding sensor 7F indicates that no following vehicle is detected behind vehicle 1 or that a following vehicle is detected at a position more than a predetermined distance away, and may otherwise determine that braking force limitation is unnecessary. In this way, braking / driving force limitation unit 87 limits the braking force based on the conditions around vehicle 1.

[0063] When another braking / driving force limiting function that has a higher priority than the function of limiting the braking / driving force by the braking / driving force limiting unit 87 is activated, the braking / driving force limiting necessity determining unit 84 may determine that it is not necessary for the braking / driving force limiting unit 87 to limit the braking force so that the other braking / driving force limiting function takes priority.

[0064] When the SOC (State of Charge) of the battery 22 of the vehicle 1, which is an electrically powered vehicle, is equal to or lower than a threshold, the allowable upper limit value selection unit 86 may reduce the threshold value used to determine whether the selected minimum allowable upper limit value is equal to or higher than the threshold. This allows the vehicle 1 to travel at as constant a speed as possible by suppressing acceleration and deceleration when the SOC is low, thereby suppressing a decrease in SOC and prioritizing improvement of the power consumption efficiency of the vehicle 1.

[0065] When it is predicted that the acceleration demand of vehicle 1 will be high, braking / driving force limiting unit 87 may not limit the driving force or may relax the limit on the driving force. Circumstances when it is predicted that the acceleration demand of vehicle 1 will be high include, for example, when the steering angle is small while traveling straight, when traveling uphill, when accelerating to overtake a preceding vehicle, or when the accelerator operation amount or accelerator operation speed is large. In other words, braking / driving force limiting unit 87 may not limit the driving force or may relax the limit on the driving force based on the steering angle, may not limit the driving force or may relax the limit on the driving force based on position information of vehicle 1, may not limit the driving force or may relax the limit on the driving force based on the situation around vehicle 1, or may not limit the driving force or may relax the limit on the driving force according to the accelerator operation amount or accelerator operation speed.

[0066] Braking / driving force limiting unit 87 may not limit the driving force or may relax the limit on the driving force when the following vehicle approaches to the extent that the distance to vehicle 1 is equal to or less than a threshold value. This allows vehicle 1 to accelerate in response to an acceleration request when the following vehicle approaches.

[0067] When the amplitude of the vertical vibration of vehicle 1 is equal to or greater than the threshold value, allowable upper limit value selection unit 86 may reduce the selected minimum allowable upper limit value by, for example, multiplying the minimum allowable upper limit value by a coefficient smaller than 1. As a result, when the amplitude of the vertical vibration is equal to or greater than the threshold value, braking / driving force limiting unit 87 further limits the braking / driving forces, thereby making it possible to prevent carsickness caused by vertical vibration from worsening.

[0068] The notification unit 88 may provide either visual or audible notification that the braking / driving force will be limited. For example, if the notification device 4 is equipped with a vibration device, the notification unit 88 may notify the occupant somatically that the braking / driving force will be limited by making the occupant feel a vibration. [Explanation of symbols]

[0069] 1...vehicle, 6...control device, 22...battery

Claims

1. A vehicle control method, comprising: calculating an index value that quantifies the degree to which the vehicle's occupants will become carsick based on the vehicle's behavior; calculating an allowable upper limit value of the longitudinal acceleration of the vehicle based on the longitudinal acceleration of the vehicle, the lateral acceleration of the vehicle, and the index value when the index value is calculated; Selecting the smallest allowable upper limit value from among the past allowable upper limit values ​​calculated from the present to a predetermined time ago; A control method for limiting the braking / driving force of the vehicle so that the longitudinal acceleration of the vehicle is within the minimum allowable upper limit value.

2. 2. The vehicle control method according to claim 1, A control method in which the predetermined time is set taking into consideration the effect that the longitudinal acceleration has on the index value.

3. 2. The vehicle control method according to claim 1, A control method for notifying the occupant when the braking / driving force of the vehicle is to be limited.

4. 4. The vehicle control method according to claim 3, A control method for visually informing the occupant.

5. 4. The vehicle control method according to claim 3, A control method for auditorily notifying the occupant.

6. 2. The vehicle control method according to claim 1, A control method that does not limit the braking force of the vehicle when there is a request to decelerate the vehicle.

7. 2. The vehicle control method according to claim 1, A control method for limiting the braking force of the vehicle based on the conditions around the vehicle.

8. 2. The vehicle control method according to claim 1, A control method in which, when it is predicted that the acceleration demand of the vehicle will become high, the driving force of the vehicle is not limited or the limit on the driving force is relaxed.

9. 9. The vehicle control method according to claim 8, A control method for not restricting the driving force of the vehicle or for easing the restriction on the driving force based on the steering angle of the vehicle.

10. 9. The vehicle control method according to claim 8, A control method for not restricting the driving force of the vehicle or for relaxing the restriction on the driving force based on the position information of the vehicle.

11. 9. The vehicle control method according to claim 8, A control method that does not limit the driving force of the vehicle or relaxes the limit on the driving force based on the situation around the vehicle.

12. 9. The vehicle control method according to claim 8, A control method for not restricting the driving force of the vehicle or for relaxing the restriction on the driving force according to the accelerator operation amount or accelerator operation speed of the vehicle.

13. 2. The vehicle control method according to claim 1, When the minimum allowable upper limit value is equal to or less than a threshold value, the threshold value is set to the minimum allowable upper limit value.

14. 14. The vehicle control method according to claim 13, The control method includes reducing the threshold value of the minimum allowable upper limit value when the vehicle is an electric vehicle and the SOC of a battery of the electric vehicle is equal to or lower than a threshold value.

15. 2. The vehicle control method according to claim 1, A control method for further restricting the braking / driving force of the vehicle when the amplitude of the vertical vibration of the vehicle is equal to or greater than a threshold value.

16. 2. The vehicle control method according to claim 1, A control method that does not limit the braking / driving force of the vehicle when the speed of the vehicle is less than a first speed threshold.

17. 17. The vehicle control method according to claim 16, A control method in which, when the speed of the vehicle is equal to or greater than the first speed threshold and less than a second speed threshold that is greater than the first speed threshold, the vehicle transitions from a state in which the braking / driving force of the vehicle is not limited to a state in which the braking / driving force is gradually limited based on the speed of the vehicle.

18. 2. The vehicle control method according to claim 1, A control method in which, when a following vehicle approaches the vehicle so closely that the distance between the following vehicle and the vehicle is equal to or less than a threshold, the driving force of the vehicle is not restricted or the restriction on the driving force of the vehicle is relaxed.

19. 2. The vehicle control method according to claim 1, A control method that allows the occupant to select whether or not to limit the braking / driving force of the vehicle.

20. A control device for a vehicle, A controller for controlling the vehicle is provided, The controller an index value calculation unit that calculates an index value that quantifies the degree to which the vehicle's occupants will become carsick based on the vehicle's behavior; an allowable upper acceleration limit calculation unit that calculates an allowable upper limit of longitudinal acceleration of the vehicle based on the longitudinal acceleration of the vehicle, the lateral acceleration of the vehicle, and the index value when the index value is calculated; an allowable upper limit value selection unit that selects the smallest allowable upper limit value from among past allowable upper limit values ​​calculated from the present until a predetermined time ago; a braking / driving force limiting unit that limits the braking / driving force of the vehicle so that the longitudinal acceleration of the vehicle is within the minimum allowable upper limit value.

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