Vehicle control method and vehicle control device

Abstract

To properly control the amount of acceleration slip when a four-wheel drive type vehicle turns out to be in an acceleration slip state.SOLUTION: A vehicle control method comprises: acquiring information on acceleration from an acceleration sensor of a four-wheel drive type vehicle, information on the rotational speed of a drive wheel from a wheel speed sensor of the vehicle, and information on driving force corresponding to the drive wheel; after an estimated speed indicating a vehicle body speed in a front-rear direction estimated from the acceleration has switched from a dropping state of being less than a calculated speed indicating a vehicle body speed calculated from the rotational speed to a non-dropping state, and a holding period in which the non-dropping state is held has passed, determining whether or not a condition to reset the estimated speed is satisfied; when the reset condition is satisfied, determining whether or not the driving force is less than a threshold value; and when the driving force is less than the threshold value, resetting the estimated speed and setting the current value of the calculated speed as a vehicle body initial speed used for estimating the estimated speed.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a technique for suppressing acceleration slip in a four-wheel drive vehicle. [Background technology]

[0002] Patent Document 1 discloses a technology for a wheel slip prevention control device that estimates vehicle speed by integrating acceleration by offsetting acceleration obtained from an acceleration sensor by a certain amount as a sensor error. In this technology, when the vehicle is in an acceleration slip state where the estimated speed estimated by integrating acceleration is lower than the calculated speed calculated from the rotation speed of the drive wheels during non-braking, the estimated speed is reset to the calculated speed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 01-101260 Summary of the Invention [Problem to be solved by the invention]

[0004] In an acceleration slip state, the estimated speed is reset to the calculated speed, so that the acceleration slip amount, which indicates the difference between the estimated speed and the calculated speed, becomes smaller. This makes it possible to suppress the intervention of the TRC (Traction Control System), which operates when the acceleration slip amount in an acceleration slip state is equal to or greater than a predetermined threshold, and to prevent excessive suppression of the driving force. In a two-wheel drive vehicle, even if the intervention of the TRC is suppressed, the estimated speed transitions to the actual vehicle speed of the driven wheels, so the driving safety of the vehicle can be ensured.

[0005] However, in a four-wheel drive vehicle, since driving force is generated in all the wheels, it is not possible to grasp whether the estimated speed is changing to the actual vehicle speed. Therefore, if the intervention of the TRC is suppressed, there is a possibility that an actual slip state in which the estimated speed exceeds the actual vehicle speed may occur, and the driving safety of the vehicle may not be ensured. In this case, it is preferable not to reset the estimated speed to the calculated speed, but in an acceleration slip state, all four wheels will be in an acceleration slip state, so the control amount for intervening the TRC will be excessive, resulting in poor acceleration. Therefore, in a four-wheel drive vehicle, an improvement is desired to appropriately control the estimated speed at an appropriate timing for controlling the acceleration slip amount in an acceleration slip state.

[0006] One object of the present disclosure is to provide a technique that can appropriately control the amount of acceleration slip when it is determined that a four-wheel drive vehicle is in an acceleration slip state. [Means for solving the problem]

[0007] The first aspect relates to a vehicle control method. The vehicle control method obtains acceleration information from an acceleration sensor of a four-wheel drive vehicle, rotational speed information of the drive wheels from wheel speed sensors of the vehicle, and drive force information corresponding to the drive wheels. Vehicle control method ,times Calculated speed indicating the vehicle speed calculated from the rolling speed is the estimated vehicle speed in the longitudinal direction estimated from the acceleration. After the estimated speed is switched from a drop state below 0.01 to a non-drop state and a holding period during which the non-drop state is maintained has elapsed, it is determined whether or not a condition for resetting the estimated speed is satisfied. The vehicle control method determines whether the driving force is less than a threshold value when the reset condition is satisfied. In the vehicle control method, when the driving force is less than a threshold value, the estimated speed is reset and the current value of the calculated speed is set as the vehicle initial speed used for estimating the estimated speed.

[0008] The second aspect has the same features as the first aspect, as well as the following features. In the vehicle control method, the estimated speed in which the current value of the calculated speed is set to the vehicle body initial speed is further multiplied by a gain.

[0009] The third aspect has the following features in addition to the first or second aspect. The reset conditions include that the estimated speed is not dropping and that the drive wheels are not being braked.

[0010] A fourth aspect has the same features as any one of the first to third aspects, and further includes the following features. The vehicle control method includes a process of setting an execution period, which is a period following the holding period and indicates a period during which setting of the vehicle body initial velocity is executed, when it is determined that the reset condition is satisfied.

[0011] A fifth aspect has the same features as any one of the first to fourth aspects, and further includes the following features. The vehicle control method includes, in a process for determining a sagging state, determining whether a driving wheel is in a braking state and Calculation speed but Estimated speed It is determined whether the state where the value of the resistance is below the threshold continues for a predetermined period or more. The vehicle control method includes, in a process for determining a sagging state, determining whether a driving wheel is in a braking state and Calculation speed but Estimated speed If it is determined that the state where the estimated speed is below this continues for a predetermined period or more, it is determined that the estimated speed is in a decreasing state.

[0012] The sixth aspect relates to a vehicle control device. The vehicle control device includes a memory device that stores acceleration information from an acceleration sensor of a four-wheel drive vehicle, information on the rotational speed of the drive wheels from wheel speed sensors of the vehicle, and information on the drive force corresponding to the drive wheels, and a processor that performs processing to suppress acceleration slip of the vehicle. The process to suppress acceleration slippage 、 times Calculated speed indicating the vehicle speed calculated from the rolling speed is the estimated vehicle speed in the longitudinal direction estimated from the acceleration.a process of determining whether a condition for resetting the estimated speed is satisfied after the estimated speed is switched from a drop state below 0 to a non-drop state and a holding period during which the non-drop state is maintained has elapsed; If it is determined that the reset condition is satisfied, a process of determining whether or not the driving force is less than a threshold value; If it is determined that the driving force is less than the threshold value, a process of resetting the estimated speed and setting the current value of the calculated speed as the vehicle initial speed used for estimating the estimated speed; Includes.

[0013] The seventh aspect has the same features as the sixth aspect, as well as the following. The estimated speed in which the current value of the calculated speed is set as the vehicle initial speed is further multiplied by a gain.

[0014] The eighth aspect has the same features as the sixth or seventh aspect, as well as the following features. The reset conditions include that the estimated speed is not dropping and that the drive wheels are not being braked.

[0015] A ninth aspect has the same features as any one of the sixth to eighth aspects, and further includes the following features. When it is determined that the reset condition is satisfied, the vehicle control device includes a process of setting an execution period that follows the holding period and indicates a period during which setting of the vehicle body initial velocity is executed.

[0016] A tenth aspect has the same features as any one of the sixth to ninth aspects, and further includes the following features. The vehicle control device, in the process of determining the sagging state, determines whether the driving wheels are in a braking state and Calculation speed but Estimated speed It is determined whether the state where the value of the resistance is below the threshold continues for a predetermined period or more. The vehicle control device, in the process of determining the sagging state, determines whether the driving wheels are in a braking state and Calculation speed but Estimated speed If it is determined that the state where the estimated speed is below this continues for a predetermined period or more, it is determined that the estimated speed is in a decreasing state. Effect of the Invention

[0017] According to the first aspect, after the estimated speed estimated from the acceleration in the longitudinal direction of the vehicle switches from a dropping state to a non-dropping state and a period during which this non-dropping state is maintained has elapsed, it is determined whether or not a reset condition is satisfied. If it is determined that the reset condition is satisfied, it is determined whether or not the driving force of the driving wheels is less than a threshold value. If it is determined that the driving force is less than the threshold value, the current value of the estimated speed is reset. In addition, the current value of the calculated speed calculated from the rotation speed of the driving wheels is set as the vehicle initial speed used for estimating the estimated speed. According to the series of processes, when a four-wheel drive vehicle is in an acceleration slip state, the estimated speed at the timing when control of the acceleration slip amount is started can be set to an appropriate value, making it possible to appropriately control the acceleration slip amount.

[0018] According to the second aspect, it is possible to appropriately control the amount of acceleration slip by the estimated speed multiplied by the gain.

[0019] According to the third aspect, it is possible to appropriately determine the timing to start control of the acceleration slip amount.

[0020] According to the fourth aspect, during the execution period, it is possible to reset the current value of the estimated speed and set the initial vehicle speed used for estimating the estimated speed.

[0021] According to the fifth aspect, it is possible to appropriately determine whether a four-wheel drive vehicle is in an acceleration slip state.

[0022] According to the sixth aspect, the same effects as those of the first aspect can be obtained.

[0023] According to the seventh aspect, the same effects as those of the second aspect can be obtained.

[0024] According to the eighth aspect, the same effects as those of the third aspect can be obtained.

[0025] According to the ninth aspect, the same effects as those of the fourth aspect can be obtained.

[0026] According to the tenth aspect, the same effects as those of the fifth aspect can be obtained. [Brief description of the drawings]

[0027] [Figure 1] 1 is a block diagram showing an example of the configuration of a vehicle control device according to an embodiment of the present invention; [Diagram 2] 2 is a block diagram showing an example of functions of a vehicle control device according to an embodiment of the present invention; FIG. [Diagram 3] 5 is a flowchart showing an example of processing by an estimated speed drop determination unit in an acceleration slip suppression processing unit of the vehicle control device according to the embodiment of the present invention. [Figure 4] 5 is a flowchart showing an example of processing by a speed control period setting processing unit in an acceleration slip suppression processing unit of the vehicle control device according to the embodiment of the present invention. [Diagram 5] 5 is a flowchart showing an example of processing by an estimated speed control processing unit in an acceleration slip suppression processing unit of the vehicle control device according to the embodiment of the present invention. [Figure 6] 5 is a diagram showing an example of processing in an acceleration slip suppression processing unit of the vehicle control device according to the embodiment of the present invention. FIG. [Figure 7] 5A to 5C are diagrams illustrating an example of a processing result in an acceleration slip suppression processing unit of the vehicle control device according to the embodiment of the present invention. [Figure 8] 5A to 5C are diagrams illustrating an example of a processing result in an acceleration slip suppression processing unit of the vehicle control device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] A vehicle control method and a vehicle control device according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. Note that the vehicle control method according to the embodiment is realized by computer processing of the vehicle control device according to the embodiment.

[0029] 1. Embodiment 1-1. Configuration example A vehicle control device 10 according to this embodiment is a device for determining the state of driving force on the driving wheels of a four-wheel drive vehicle (hereinafter also simply referred to as "vehicle") during a predetermined period of acceleration slippage in order to suppress acceleration slippage in the vehicle, and for controlling an estimated speed based on the determination result. The vehicle control device according to this embodiment is mounted on a vehicle. FIG. 1 is a block diagram showing an example of the configuration of the vehicle control device 10 according to this embodiment.

[0030] The vehicle control device 10 performs various information processing. The vehicle control device 10 includes one or more processors 100 (hereinafter simply referred to as the processor 100) and one or more storage devices 110 (hereinafter simply referred to as the storage device 110). The processor 100 executes various processing. For example, the processor 100 may be a CPU. The storage device 110 stores data of acceleration information 120, data of rotation speed information 130 of the driving wheels, and data of driving force information 140. Examples of the storage device 110 include a volatile memory, a non-volatile memory, a HDD, and an SSD. The processor 100 executes a vehicle control program, which is a computer program, to realize the functions of the vehicle control device 10. The vehicle control program is stored in the storage device 110. The vehicle control program may be recorded in a computer-readable recording medium. The vehicle control program may be provided via a network.

[0031] The acceleration information 120 includes information on the acceleration in the longitudinal direction of the vehicle obtained from an acceleration sensor mounted on the vehicle. The drive wheel rotation speed information 130 includes information on the rotation speeds of all the drive wheels of the vehicle obtained from wheel speed sensors mounted on these drive wheels. The drive force information 140 includes information on the drive forces for all the drive wheels obtained from a drive unit mounted on the vehicle.

[0032] 1-2. Details of information processing The vehicle control device 10 estimates the state of the vehicle body speed based on acceleration information 120 and drive wheel rotation speed information 130. Then, depending on the state of the estimated speed, a predetermined period during which the estimated speed can be controlled is set. Furthermore, based on the drive force information 140, the state of the drive force during the predetermined period is determined, and based on the determination result, control is performed to set the estimated speed to an appropriate speed, and acceleration slip suppression processing is executed to suppress acceleration slip. The information processing according to this embodiment includes characteristic processing as described below.

[0033] 2 is a block diagram showing an example of functions related to information processing according to this embodiment. The vehicle control device 10 includes, as functional blocks, an information input unit 200, an acceleration slip suppression processing unit 300, and a processing result output unit 400. These functional blocks are realized by the processor 100 executing a vehicle control program.

[0034] The information input unit 200 performs a process of inputting the acceleration information 120, the drive wheel rotation speed information 130, and the driving force information 140 recorded in the storage device 110. After that, the input acceleration information 120, the drive wheel rotation speed information 130, and the driving force information 140 are output to the acceleration slip suppression processing unit 300.

[0035] The acceleration slip suppression processing unit 300 further includes a vehicle body speed calculation unit 310, an estimated speed drop determination unit 320, a speed control period setting processing unit 330, an estimated speed control processing unit 340, and a control amount generation processing unit 350. The acceleration slip suppression processing unit 300 determines whether or not there is a sign of acceleration slip occurring based on the input acceleration information 120, the driving wheel rotation speed information 130, and the driving force information 140. If it is determined that there is a sign of acceleration slip occurring, it sets a predetermined period during which the estimated speed can be controlled, and determines the state of the driving force during the predetermined period. Depending on the determination result, it controls the estimated speed to a speed that can suppress acceleration slip. The details of each process of the vehicle body speed calculation unit 310, the estimated speed drop determination unit 320, the speed control period setting processing unit 330, the estimated speed control processing unit 340, and the control amount generation processing unit 350 will be described later.

[0036] The vehicle speed calculation unit 310 calculates an estimated speed indicating the vehicle speed estimated by adding an integral value obtained by integrating the input acceleration information 120 to the vehicle speed. Also, it calculates a calculated speed indicating the vehicle speed based on the input drive wheel rotation speed information 130.

[0037] The estimated speed drop determination unit 320 determines whether the estimated speed is in a "dropping state" based on the estimated speed calculated by the vehicle speed calculation unit 310 and the calculated speed. If the estimated speed is determined to be in a "dropping state", it is determined that there is a sign of an acceleration slip occurring. The processing of the estimated speed drop determination unit 320 will be described in detail later.

[0038] When the estimated speed drop determination unit 320 determines that the estimated speed is in a "dropped state", the speed control period setting processing unit 330 determines whether or not a reset condition is satisfied after the estimated speed switches from the "dropped state" to the "non-dropped state" and a retention period indicating the period during which the "non-dropped state" is maintained has elapsed. When it is determined that the reset condition is satisfied, an execution period during which the estimated speed can be controlled is set.

[0039] The reset condition is a condition that includes the estimated speed being in a "not dropping" state after the estimated speed has switched from a "dropping state" to a "not dropping state" and the driving wheels not being in a braking state after the "not dropping state" has continued for a retention period after the estimated speed has switched from a "dropping state" to a "not dropping state", and the driving wheels not being in a braking state. The process of the speed control period setting processor 330 will be described in detail later.

[0040] The estimated speed control processing unit 340 resets the current value of the estimated speed based on the state of the driving force during the execution period set by the speed control period setting processing unit 330, and performs control to set the current value of the calculated speed as the vehicle initial speed used for estimating the estimated speed. The processing of the estimated speed control processing unit 340 will be described in detail later.

[0041] The control amount generation processing unit 350 generates a control amount for controlling the driving force based on the estimated speed generated by the estimated speed control processing unit 340.

[0042] The processing result output unit 400 performs processing to output the control amount generated by the acceleration slip suppression processing unit 300 to the drive device.

[0043] FIG. 3 is a flowchart showing an example of processing by the estimated speed drop determination unit 320.

[0044] In step S100, estimated speed drop determination unit 320 determines whether or not the driving wheels are in a braking state.

[0045] If it is determined that the driving wheels are in a braking state (step S100; Yes), the process proceeds to step S110. Otherwise (step S100; No), the process proceeds to step S130.

[0046] In step S110, estimated speed drop determination unit 320 determines whether or not a state in which the calculated speed is less than the estimated speed continues for a predetermined period of time or more.

[0047] If it is determined that the state in which the calculated speed is less than the estimated speed continues for a predetermined time or more (step S110; Yes), the process proceeds to step S120. Otherwise (step S110; No), the process proceeds to step S130.

[0048] In step S120, the estimated speed drop determination unit 320 determines that the estimated speed is in a "dropping state."

[0049] In step S130, estimated speed drop determination unit 320 determines that the estimated speed is in a "non-dropping state."

[0050] In step S140, the estimated speed drop determination unit 320 outputs the result of the determination.

[0051] FIG. 4 is a flowchart showing an example of processing by the speed control period setting processor 330.

[0052] In step S200, speed control period setting processor 330 determines whether there is a timing at which the estimated speed determined by estimated speed drop determiner 320 switches from a "dropped state" to a "non-dropped state".

[0053] If it is determined that there is a timing when the estimated speed switches from a "dropping state" to a "non-dropping state" (step S200; Yes), the process proceeds to step S210. Otherwise (step S200; No), the process proceeds to step S240.

[0054] In step S210, after the estimated speed is switched to a "state without a drop", the speed control period setting processor 330 determines whether or not the "state without a drop" continues for a holding period.

[0055] If it is determined that the "non-drop state" of the estimated speed continues for the holding period (step S210; Yes), the process proceeds to step S220. Otherwise (step S210; No), the process proceeds to step S240.

[0056] In step S220, the speed control period setting processor 330 determines whether the driving wheels are not in a braking state.

[0057] If it is determined that the driving wheels are not in a braking state (step S220; Yes), the process proceeds to step S230. Otherwise (step S220; No), the process proceeds to step S240.

[0058] In step S230, the speed control period setting processor 330 sets an execution period, which indicates a period during which control of the estimated speed is executed, as a period following the holding period.

[0059] In step S240, the speed control period setting processor 330 performs a setting so that control of the estimated speed is not executed.

[0060] In step S250, speed control period setting processor 330 outputs the result of the setting.

[0061] FIG. 5 is a flowchart showing an example of processing by the estimated speed control processor 340.

[0062] In step S300, estimated speed control processing unit 340 determines whether or not the driving force is less than a threshold value during the execution period, set by speed control period setting processing unit 330, during which the estimated speed can be controlled.

[0063] If it is determined that the driving force is less than the threshold value (step S300; Yes), the process proceeds to step S310. Otherwise (step S300; No), the process proceeds to step S320.

[0064] In step S310, the estimated speed control processing unit 340 resets the current value of the estimated speed, and sets the current value of the calculated speed as the initial vehicle speed used to estimate the estimated speed.

[0065] In step S320, the estimated speed control processing unit 340 performs a setting such that the current value of the estimated speed is not reset.

[0066] In step S330, the estimated speed control processor 340 outputs the set result.

[0067] FIG. 6 is a diagram showing an example of processing by the acceleration slip suppression processing unit 300. Here, an example of processing in which the estimated speed drop determination unit 320 determines that the estimated speed is in a "dropped state" and an example of processing in which the speed control period setting processing unit 330 sets an execution period during which the estimated speed can be controlled will be described. First, an example of processing in which the estimated speed drop determination unit 320 determines that the estimated speed is in a "dropped state" will be described. Specifically, when the conditions are met that the driving wheels are in a braking state and the state in which the calculated speed is less than the estimated speed continues for a predetermined period or more, the estimated speed is determined to be in a "dropped state". When the conditions are not met, the estimated speed is determined to be in a "non-dropped state".

[0068] Next, an example of processing for setting an execution period during which the estimated speed can be controlled in the speed control period setting processor 330 will be described. Specifically, after the estimated speed switches from a "dropped state" to a "non-dropped state", and the "non-dropped state" continues for a retention period, if reset conditions are satisfied, including the estimated speed being in a "non-dropped state" and the driving wheels not being in a braking state, an execution period during which the estimated speed can be controlled is set. During this execution period, control is performed to reset the current value of the estimated speed based on the state of the driving force, and set the current value of the calculated speed to the vehicle initial speed used to estimate the estimated speed.

[0069] FIG. 7 is a diagram showing an example of the processing result in the acceleration slip suppression processing unit 300. First, the relationship between the state of the estimated speed and the acceleration slip will be described. Then, the manner in which the acceleration slip amount changes when the estimated speed is not controlled and when the estimated speed is controlled will be described. Specifically, when the estimated speed falls below the calculated speed after the driving wheels are switched from the braking state to the non-braking state, an acceleration slip state occurs, which indicates that the vehicle is apparently slipping. In this state, if the difference between the calculated speed and the estimated speed is small, the acceleration slip amount also becomes small. On the other hand, if the difference between the calculated speed and the estimated speed is large, the acceleration slip amount also becomes large. In other words, it can be said that the difference between the calculated speed and the estimated speed is proportional to the acceleration slip amount. Therefore, in the state before the control in which the estimated speed is not controlled, the calculated speed is not set to the vehicle initial speed of the estimated speed, so the difference between the calculated speed and the estimated speed becomes large, and as a result, the acceleration slip amount also becomes large. On the other hand, in the state after the estimated speed is controlled, the calculated speed is set to the initial vehicle speed of the estimated speed, so the difference between the calculated speed and the estimated speed becomes small, and as a result, the amount of acceleration slippage also becomes small.

[0070] FIG. 8 is a diagram showing an example of the processing result in the acceleration slip suppression processing unit 300. In FIG. 7, it has been described that the acceleration slip amount can be reduced by controlling the estimated speed. Here, an example of a suppression method for further reducing the acceleration slip amount in a state after the estimated speed is controlled will be given. Specifically, the estimated speed estimated based on the result of the estimated speed control processing unit 340 is multiplied by a gain. As a result, compared to the state of the estimated speed before multiplication by the gain, the difference between the calculated speed and the estimated speed becomes smaller, and as a result, the acceleration slip amount also becomes smaller. Examples of the gain include a predetermined value, a value obtained by adding a fixed amount to the acceleration, and the like.

[0071] 1-3.Effects By determining whether the estimated speed is in a "dropped state" or a "non-dropped state", it is possible to detect in advance the acceleration slip that occurs when the driving wheels transition from a braking state to a non-braking state. In addition, by setting an execution period during which the estimated speed can be controlled in the acceleration slip state and monitoring the state of the driving force corresponding to the driving wheels during the execution period, it is possible to determine whether it is an appropriate timing to suppress the acceleration slip amount. Furthermore, by resetting the current value of the estimated speed based on the state of the driving force and setting the current value of the calculated speed to the vehicle initial speed used for estimating the estimated speed, it is possible to set the estimated speed to an appropriate speed. This makes it possible to suppress poor acceleration due to the intervention of the TRC, and also makes it possible to suppress an actual slip state in which the estimated speed exceeds the actual vehicle speed. In this way, according to the present disclosure, when it is found that a four-wheel drive vehicle is in an acceleration slip state, it is possible to appropriately control the acceleration slip amount. [Explanation of symbols]

[0072] 10 Vehicle control device 100 processors 110 Storage device 120 Acceleration Information 130 Drive wheel rotation speed information 140 Driving Force Information 200 Information input section 300 Acceleration slip suppression processing unit 310 Vehicle speed calculation unit 320 Estimated speed drop judgement unit 330 Speed ​​control period setting processing unit 340 Estimated speed control processing unit 350 Control amount generation processing unit 400 Processing result output section

Claims

1. Acquire acceleration information from an acceleration sensor of a four-wheel drive vehicle, information on the rotational speed of the drive wheels from a wheel speed sensor of the vehicle, and information on the drive force corresponding to the drive wheels; determining whether or not a condition for resetting the estimated speed is satisfied after a calculated speed indicating a vehicle body speed calculated from the rotation speed is switched from a drop state below an estimated speed indicating a vehicle body speed in a longitudinal direction estimated from the acceleration to a non-drop state and a holding period during which the non-drop state is maintained has elapsed; If the reset condition is satisfied, determining whether the driving force is less than a threshold; When the driving force is less than the threshold value, the estimated speed is reset and the current value of the calculated speed is set as the vehicle initial speed used for estimating the estimated speed. A vehicle control method.

2. 2. A vehicle control method according to claim 1, The estimated speed in which the current value of the calculated speed is set to the vehicle initial speed is further multiplied by a gain. A vehicle control method.

3. 3. A vehicle control method according to claim 1, further comprising: The reset condition is The estimated speed is not in a state of decreasing, and the driving wheels are not in a state of braking. A vehicle control method.

4. A vehicle control method according to any one of claims 1 to 3, When it is determined that the reset condition is satisfied, a process of setting an execution period which is a period following the holding period and indicates a period during which the setting of the vehicle body initial speed is executed is included. A vehicle control method.

5. A vehicle control method according to any one of claims 1 to 4, In the process of determining the drop state, determining whether or not a state in which the drive wheels are in a braking state and the calculated speed is lower than the estimated speed continues for a predetermined period of time or more; When it is determined that the driving wheels are in a braking state and the state in which the calculated speed is lower than the estimated speed continues for the predetermined period or more, it is determined that the estimated speed is in the dropping state. A vehicle control method.

6. a storage device that stores acceleration information from an acceleration sensor of a four-wheel drive vehicle, information on the rotational speed of the drive wheels from wheel speed sensors of the vehicle, and information on the drive force corresponding to the drive wheels; and a processor that performs processing to suppress acceleration slip of the vehicle, The process of suppressing acceleration slip is a process of determining whether or not a condition for resetting the estimated speed is satisfied after a calculated speed indicating a vehicle body speed calculated from the rotation speed is switched from a dropped state, in which the calculated speed is lower than an estimated speed indicating a vehicle body speed in a longitudinal direction estimated from the acceleration, to a non-dropped state, and after a holding period during which the non-dropped state is maintained has elapsed; If it is determined that the reset condition is satisfied, a process of determining whether the driving force is less than a threshold value; a process of resetting the estimated speed and setting a current value of the calculated speed as an initial vehicle speed used for estimating the estimated speed when the driving force is determined to be less than the threshold value; A vehicle control device comprising:

7. The vehicle control device according to claim 6, The estimated speed in which the current value of the calculated speed is set to the vehicle initial speed is further multiplied by a gain. Vehicle control device.

8. The vehicle control device according to claim 6 or 7, The reset condition is The estimated speed is not in a state of decreasing, and the driving wheels are not in a state of braking. Vehicle control device.

9. The vehicle control device according to any one of claims 6 to 8, and when it is determined that the reset condition is satisfied, a process of setting an execution period which is a period following the holding period and indicates a period during which the setting of the vehicle speed is to be executed. Vehicle control device.

10. The vehicle control device according to any one of claims 6 to 9, In the process of determining the drop state, determining whether or not a state in which the drive wheels are in a braking state and the calculated speed is lower than the estimated speed continues for a predetermined period of time or more; When it is determined that the driving wheels are in a braking state and the state in which the calculated speed is lower than the estimated speed continues for the predetermined period or more, it is determined that the estimated speed is in the dropping state. Vehicle control device.

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