Vehicle braking control device, vehicle braking control method and computer program

Abstract

To provide an improved vehicle braking control device that can stabilize behavior of a vehicle body during anti-skid control.SOLUTION: A vehicle braking control device, which executes anti-skid control, executes: setting of a target yaw rate and target vehicle body angular acceleration during anti-skid control; calculation of front and rear force differences of left and right wheels, on the basis of front and rear force of the wheels detected with a tire force sensor during the anti-skid control; calculation of an actual yaw rate and actual vehicle body angular acceleration on the basis of the front and rear force differences of the left and right wheels; and suppression of braking force or increase of driving force which is applied to either of the left and right wheels, so as to keep a deviation of yaw rates which is a difference between the target yaw rate and the actual yaw rate and a deviation of vehicle body angular acceleration which is a difference between the target vehicle body angular acceleration and the actual vehicle body angular acceleration, within a predetermined range, when the deviation of yaw rates is over a predetermined first threshold or the deviation of vehicle body angular acceleration is over a predetermined second threshold.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle braking control device, a vehicle braking control method, and a computer program. [Background technology]

[0002] Anti-skid brake systems (hereinafter also referred to as "ABS") are known that prevent a vehicle from sliding due to wheel lock when braking. For example, when strong braking is applied under low-friction conditions where the coefficient of friction between the tires and the road surface is low, the ABS reduces braking force when it detects that the vehicle is sliding due to wheel lock, and then increases braking force again when the wheels start to rotate, repeating this process to ensure that each wheel exerts maximum braking force.

[0003] During anti-skid control by ABS, upper and lower limits are set for the tire slip ratio, and braking force is controlled so that the slip ratio falls within the upper and lower limits. Therefore, when the braking force is constant and the road surface changes from a low friction coefficient to a high friction coefficient, the slip ratio decreases, and anti-skid control intervenes, increasing the braking force to increase the slip ratio.

[0004] When braking the vehicle, if only one of the left and right wheels changes from a low friction state to a high friction state, the braking force of that wheel increases, creating a difference in braking force between the left and right wheels and generating a yaw moment on the vehicle. In a low friction state, unless the tire slip angle changes significantly, the force in the width direction of the tire (lateral force) does not increase, which can easily disrupt the behavior of the vehicle.

[0005] In response to this, Patent Document 1 discloses a technology that, when it is detected that one wheel has changed from a low-friction state for both left and right wheels to a high-friction state during braking, limits the increase in brake fluid pressure generated in the wheel cylinder of the wheel with high friction so that the deviation between the detected yaw rate and a set target yaw rate is equal to or less than a predetermined value. Specifically, the brake control device described in Patent Document 1 is configured to increase the wheel cylinder fluid pressure during ABS control pressure increase for the wheel with high friction at the maximum gradient when the yaw rate deviation is less than a predetermined value, and to keep it constant when the yaw rate deviation is equal to or greater than the predetermined value. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-171294 Summary of the Invention [Problem to be solved by the invention]

[0007] However, instantaneous and accurate estimation of the road surface friction coefficient is technically difficult and not easy. Even if it were possible to instantaneously and accurately estimate the road surface friction coefficient using, for example, the tire force generated in the only tire that contacts the road surface or a detected value correlated with the tire force, the tire force cannot be reflected in the estimated value of the friction coefficient until after it has actually been generated, resulting in free running time.

[0008] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide an improved vehicle braking control device, vehicle braking control method, and computer program that are capable of stabilizing the behavior of the vehicle body during anti-skid control. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, according to an aspect of the present disclosure, there is provided a brake control device for a vehicle that performs anti-skid control, comprising one or more processors and one or more memories communicably connected to the one or more processors, wherein the one or more processors perform the following operations: set a target yaw rate and a target vehicle body angular acceleration during the anti-skid control; calculate a longitudinal force difference between left and right wheels based on longitudinal forces of each wheel detected by a tire force sensor during the anti-skid control; calculate an actual yaw rate and an actual vehicle body angular acceleration based on the longitudinal force difference between the left and right wheels; and, when a yaw rate deviation, which is the difference between the target yaw rate and the actual yaw rate, is equal to or greater than a predetermined first threshold value, or when a vehicle body angular acceleration deviation, which is the difference between the target vehicle body angular acceleration and the actual vehicle body angular acceleration, is equal to or greater than a predetermined second threshold value, reduce the braking force applied to one of the left and right wheels or increase the driving force, thereby keeping the yaw rate deviation and the vehicle body angular acceleration deviation within a predetermined range.

[0010] Furthermore, in order to solve the above-described problems, according to another aspect of the present disclosure, there is provided a vehicle braking control method in which a computer sets a target yaw rate and a target vehicle body angular acceleration during anti-skid control, calculates a longitudinal force difference between the left and right front wheels and a longitudinal force difference between the left and right rear wheels based on the longitudinal forces of each wheel detected by a tire force sensor during the anti-skid control, calculates a yaw rate and a vehicle body angular acceleration based on the longitudinal force difference between the left and right front wheels and the longitudinal force difference between the left and right rear wheels, and when a yaw rate deviation, which is the difference between the target yaw rate and the yaw rate, is equal to or greater than a predetermined first threshold value, or when a vehicle body angular acceleration deviation, which is the difference between the target vehicle body angular acceleration and the vehicle body angular acceleration, is equal to or greater than a predetermined second threshold value, reduces the braking force applied to either the left or right wheel of at least one of the front wheels and the rear wheels or increases the driving force, thereby keeping the yaw rate deviation and the vehicle body angular acceleration deviation within a predetermined range.

[0011] Furthermore, in order to solve the above-mentioned problems, according to another aspect of the present disclosure, there is provided a computer program that causes a computer to execute the following steps: set a target yaw rate and a target vehicle body angular acceleration during anti-skid control; calculate a lateral force difference between the left and right front wheels and a lateral force difference between the left and right rear wheels based on the lateral forces of each wheel detected by a tire force sensor during the anti-skid control; calculate a yaw rate and a vehicle body angular acceleration based on the lateral force difference between the left and right front wheels and the lateral force difference between the left and right rear wheels; and, when a yaw rate deviation, which is the difference between the target yaw rate and the yaw rate, is equal to or greater than a predetermined first threshold value, or when a vehicle body angular acceleration deviation, which is the difference between the target vehicle body angular acceleration and the vehicle body angular acceleration, is equal to or greater than a predetermined second threshold value, reduce the braking force applied to either the left or right wheel of at least one of the front wheels and the rear wheels, or increase the driving force, to keep the yaw rate deviation and the vehicle body angular acceleration deviation within a predetermined range. [Effects of the Invention]

[0012] As described above, according to the present disclosure, the behavior of the vehicle body can be stabilized during anti-skid control. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating an example configuration of a vehicle equipped with a vehicle braking control device according to an embodiment of the present disclosure. [Figure 2] 2 is a block diagram showing an example of the configuration of a braking control device for a vehicle according to the embodiment; FIG. [Figure 3] 4 is a flowchart showing a routine of a processing operation by the braking control device for a vehicle according to the embodiment; [Figure 4] 4 is a flowchart showing a routine of a processing operation by the braking control device for a vehicle according to the embodiment; [Figure 5] 4 is a flowchart showing a routine of a vehicle body behavior stabilization process performed by the vehicle braking control device according to the embodiment; [Figure 6] 3 is an explanatory diagram showing the operation of the vehicle braking control device according to the embodiment; FIG. [Figure 7]10 is a flowchart showing a routine of a vehicle body behavior stabilization process performed by a braking control device for a vehicle according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0015] <1. Vehicle configuration> First, an example of the overall configuration of a vehicle equipped with a vehicle braking control device according to an embodiment of the present disclosure will be described.

[0016] FIG. 1 is a schematic diagram showing an example of the configuration of a vehicle 1. As shown in FIG. The vehicle 1 is configured as a four-wheel drive automobile in which drive torque output from a drive force source 2 that generates drive torque is transmitted to a left front wheel 5LF, a right front wheel 5RF, a left rear wheel 5LR, and a right rear wheel 5RR (hereinafter collectively referred to as "wheels 5" unless a distinction is required. The left front wheel 5LF and the right front wheel 5RF may be referred to as "front wheels 5F," and the left rear wheel 5LR and the right rear wheel 5RR may be referred to as "rear wheels 5R"). The drive force source 2 may be an internal combustion engine such as a gasoline engine or a diesel engine, a drive motor, or may be equipped with both an internal combustion engine and a drive motor.

[0017] The driving force source control device 21 includes a processor such as a CPU (Central Processing Unit) and controls the driving of the driving force source 2. The driving torque output from the driving force source 2 is distributed to the left and right front wheels 5F via the front wheel differential 3F and the left and right axles 4LF, 4RF. The driving torque is also distributed to the left and right front wheels 5F via a propeller shaft (not shown). The driving torque output from the driving force source 2 is also distributed to the left and right rear wheels 5R via a propeller shaft (not shown), the rear wheel differential 3R, and the left and right axles 4LR, 4RR.

[0018] Vehicle 1 may be a two-wheel drive vehicle that transmits drive torque to either the front or rear wheels. Vehicle 1 may also be an electric vehicle equipped with two drive motors, for example, a front-wheel drive motor and a rear-wheel drive motor, or an electric vehicle equipped with drive motors corresponding to each of the wheels 5. If vehicle 1 is an electric vehicle or hybrid electric vehicle, vehicle 1 is equipped with a secondary battery that stores power supplied to the drive motors, and a generator that generates power to charge the secondary battery.

[0019] The vehicle 1 also includes a hydraulic brake system that generates braking force on each wheel 5. The hydraulic brake system includes a master cylinder 6, wheel cylinders 7LF, 7RF, 7LR, and 7RR (hereinafter collectively referred to as "wheel cylinders 7" unless a distinction is required) provided on each wheel 5, and a hydraulic control unit 20. Brake fluid supplied from the master cylinder 6 in accordance with the amount of brake pedal operation by the driver is supplied to the wheel cylinders 7 of each wheel 5 via the hydraulic control unit 20, generating braking pressure on each wheel 5.

[0020] The hydraulic control unit 20 includes a motor pump and a plurality of control valves. The hydraulic control unit 20 is controlled by the brake control device 50 to increase and decrease the brake pressure for each wheel 5. If the vehicle 1 is an electric vehicle or a hybrid electric vehicle, the hydraulic brake system may be used in combination with regenerative braking using a drive motor.

[0021] Each wheel 5 is provided with a tire force sensor 8LF, 8RF, 8LR, 8RR (hereinafter collectively referred to as "tire force sensor 8" unless a distinction is particularly required) and a wheel speed sensor 9LF, 9RF, 9LR, 9RR (hereinafter collectively referred to as "wheel speed sensor 9" unless a distinction is particularly required).

[0022] The tire force sensor 8LF is provided, for example, on the left front axle 4LF at the connection between the left front axle 4LF and the left front wheel 5LF. The tire force sensor 8RF is provided, for example, on the right front axle 4RF at the connection between the right front axle 4RF and the right front wheel 5RF. The tire force sensor 8LR is provided, for example, on the left rear axle 4LR at the connection between the left rear axle 4LR and the left rear wheel 5LR. The tire force sensor 8RR is provided, for example, on the right rear axle 4RR at the connection between the right rear axle 4RR and the right rear wheel 5RR. The tire force sensors 8 are load sensors that detect the load applied to each wheel 5.

[0023] For example, the tire force sensor 8 may be a six-component force detector that detects loads (Fx, Fy, Fz) generated in each of the three axial directions of the wheel 5, namely the fore-and-aft direction (x-axis), width direction (y-axis), and height direction (z-axis), as well as moments (Mx, My, Mz) generated around each of the three axes. In this embodiment, the load generated in the fore-and-aft direction (x-axis direction) of the contact surface of the wheel 5 is referred to as the fore-and-aft force Fx, the load generated in the width direction (y-axis direction) is referred to as the lateral force Fy, and the load generated in the height direction (z-axis direction) is referred to as the ground reaction force Fz.

[0024] The wheel speed sensor 9 is provided on the axle 4 of each wheel 5 (front left axle 4LF, front right axle 4RF, rear left axle 4LR, and rear right axle 4RR) to detect the rotation speed of each wheel 5.

[0025] The vehicle 1 also includes a steering angle sensor 11, a brake sensor 13, and a yaw rate sensor 15. The steering angle sensor 11 is provided, for example, on a steering column and detects the rotation angle of the steering wheel. The brake sensor 13 is provided on a brake pedal or brake rod and detects the amount of brake pedal operation. The yaw rate sensor 15 is provided, for example, near the center of gravity of the vehicle body and detects the rotation angular velocity of the vehicle 1 around the z-axis.

[0026] The braking control device 50 includes one or more electronic control devices that control the braking of the vehicle 1. The braking control device 50 acquires detection information output from various sensors and executes control to stabilize vehicle behavior, including anti-skid control.

[0027] <2. Vehicle Braking Control Device> Next, the vehicle braking control device 50 according to this embodiment will be described in detail.

[0028] (2-1. Overall configuration of braking control device) The braking control device 50 functions as a device that controls the braking of the vehicle body by having one or more processors such as CPUs execute a computer program. The computer program is a computer program that causes the processor to execute the operations described below that should be performed by the braking control device 50. The computer program executed by the processor may be recorded on a recording medium that functions as a storage unit (memory) 53 provided in the braking control device 50, or may be recorded on a recording medium built into the braking control device 50 or any recording medium that can be externally attached to the braking control device 50.

[0029] Recording media for recording computer programs include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical recording media such as CD-ROMs (Compact Disc Read Only Memory), DVDs (Digital Versatile Discs), and Blu-ray (registered trademark), magneto-optical media such as floptical disks, memory elements such as RAMs (Random Access Memory) and ROMs (Read Only Memory), flash memories such as USB (Universal Serial Bus) memories and SSDs (Solid State Drives), and other media capable of storing programs.

[0030] FIG. 2 is a block diagram showing an example of the configuration of the braking control device 50. As shown in FIG. The braking control device 50 is connected to a tire force sensor 8, a wheel speed sensor 9, a steering angle sensor 11, a brake sensor 13, and a yaw rate sensor 15 via a dedicated line or communication means such as a CAN (Controller Area Network) or a LIN (Local Inter Net). In addition, the braking control device 50 is connected to a hydraulic pressure control unit 20 and a driving force source control device 21 so as to be able to communicate with each other.

[0031] The braking control device 50 includes a processing unit 51 and a storage unit 53. The processing unit 51 is configured with one or more processors such as CPUs and various peripheral components. Part or all of the processing unit 51 may be configured with updatable firmware or the like, or may be a program module or the like that is executed by commands from the CPU or the like.

[0032] The storage unit 53 is configured with one or more storage elements such as RAM or ROM connected to the processing unit 51 so as to be able to communicate with it. However, the type and number of storage units 53 are not particularly limited. The storage unit 53 stores information such as computer programs executed by the processing unit 51, various parameters used in arithmetic processing, detection data, and arithmetic results. A part of the storage unit 53 is used as a work area for the processing unit 51.

[0033] (2-2. Functional configuration of the processing unit) Next, the configuration of the processing unit 51 of the braking control device 50 will be described. The processing unit 51 includes an acquisition unit 61, a running state calculation unit 63, an anti-skid control unit 65, a longitudinal force difference calculation unit 67, a target running state calculation unit 69, and a vehicle body behavior stabilization control unit 71. Each of these units is a function realized by execution of a computer program by one or more processors. However, part of the acquisition unit 61, the running state calculation unit 63, the anti-skid control unit 65, the longitudinal force difference calculation unit 67, the target running state calculation unit 69, and the vehicle body behavior stabilization control unit 71 may be configured by hardware such as an analog circuit.

[0034] Below, the function of each part of the processing unit 51 will be briefly explained, and then the specific processing content of each part will be explained.

[0035] (Acquisition Department) The acquisition unit 61 acquires detection information output from various sensors. For example, the acquisition unit 61 acquires sensor signals output from the tire force sensor 8, the wheel speed sensor 9, the steering angle sensor 11, the brake sensor 13, and the yaw rate sensor 15 at a predetermined sampling period, and detects the six-component forces generated in each wheel 5, the rotational speed of each wheel 5, the steering angle, the amount of brake pedal operation, and the yaw rate (actual yaw rate) of the vehicle body.

[0036] (Driving condition calculation unit) The running condition calculation unit 63 calculates information about the running condition of the vehicle 1. For example, the running condition calculation unit 63 calculates a differential value of the rotational speed of each wheel 5 to calculate the rotational acceleration of each wheel 5 (hereinafter also referred to as "wheel acceleration"). The running condition calculation unit 63 also calculates the vehicle body speed based on the rotational speed of each wheel 5. The running condition calculation unit 63 also calculates the yaw moment of the vehicle body based on the longitudinal force Fx and lateral force Fy generated on each wheel 5, the toe angle θ of each wheel 5, the tread length, and the shortest distance from the center of gravity of the vehicle body to the axle, and calculates the angular acceleration of the vehicle body (hereinafter also referred to as "vehicle body angular acceleration") by dividing the yaw moment by the inertia of the vehicle body. Furthermore, the running condition calculation unit 63 calculates the slip state of each wheel 5 based on the vehicle body speed and the wheel speed. The slip state of the wheel 5 is a state quantity that represents the degree of grip of the wheel 5 with respect to the road surface on which the vehicle is traveling.

[0037] (Anti-skid control unit) The anti-skid control unit 65 executes a process to prevent each wheel 5 from locking when the brake pedal is depressed strongly. For example, the anti-skid control unit 65 executes anti-skid control based on the wheel acceleration, the slip state of the wheels 5, the amount of brake pedal operation, the required deceleration, the vehicle speed, the yaw rate, the steering angle, and the vehicle lateral acceleration. Note that the process of anti-skid control is a conventionally known method and is not limited to the above example.

[0038] (Anteroposterior force difference calculation section) The longitudinal force difference calculation unit 67 calculates the difference (longitudinal force difference ΔFx_f) between the forces (longitudinal forces Fx) generated in the direction along the axle 4F for each of the left and right front wheels 5F, and the difference (longitudinal force difference ΔFx_r) between the forces (longitudinal forces Fx) generated in the direction along the axle 4R for each of the left and right rear wheels 5R.

[0039] (Target driving state calculation unit) The target driving state calculation unit 69 sets a target yaw rate and a target vehicle body angular acceleration while anti-skid control is being executed. For example, the target driving state calculation unit 69 calculates the target yaw rate using a predetermined stabilization coefficient based on the steering angle and vehicle body speed. The target yaw rate represents a target value for the yaw rate of the vehicle body determined from the driving operation state of the driver of the vehicle 1. In addition, the target driving state calculation unit 69 calculates the target vehicle body angular velocity based on the steering angle, vehicle body weight, cornering stiffness, and the shortest distance from the center of gravity of the vehicle body to the axle.

[0040] (Vehicle behavior stabilization control unit) The vehicle behavior stabilization control unit 71 suppresses the braking force generated in each wheel 5 based on the difference between the target yaw rate and the actual yaw rate (yaw rate deviation) and the difference between the target vehicle angular acceleration and the actual vehicle angular acceleration (vehicle angular acceleration deviation), and performs processing to stabilize the driving state.

[0041] <3. Operation of braking control device> Next, an example of the processing operation by the processing unit 51 of the braking control device 50 according to this embodiment will be specifically described with reference to a flowchart. To make the description easier to understand, the description will be mainly given by taking as an example a situation in which one of the left and right wheels slips when the vehicle is traveling straight ahead.

[0042] 3 and 4 show a main routine of the processing operation by the braking control device 50. FIG. When the processing unit 51 detects that the ignition switch of the vehicle 1 has been turned on (step S11), the acquisition unit 61 of the processing unit 51 starts a process of acquiring various detection information based on sensor signals output from the various sensors (step S13). For example, the acquisition unit 61 acquires sensor signals output from the tire force sensor 8, the wheel speed sensor 9, the steering angle sensor 11, the brake sensor 13, and the yaw rate sensor 15 at a predetermined sampling period, and detects the six-component forces (Fx, Fy, Fz, Mx, My, Mz) generated in each wheel 5, the rotational speed Vw (Vw_LF, Vw_RF, Vw_LR, Vw_RR) of each wheel 5, the steering angle θs, the brake pedal operation amount Ba, and the yaw rate (actual yaw rate) Yr of the vehicle body.

[0043] Next, the running condition calculation unit 63 of the processing unit 51 calculates the wheel acceleration dVw (dVw_LF, dVw_RF, dVw_LR, dVw_RR) of each wheel 5 based on the rotational speed Vw of each wheel 5 (step S15). For example, the running condition calculation unit 63 differentiates the rotational speed Vw of each wheel 5 to calculate the wheel acceleration dVw of each wheel 5.

[0044] Next, the traveling condition calculation unit 63 calculates the vehicle body speed Vx based on the rotational speed Vw of each wheel 5 (step S17). For example, when no braking force is being applied to each wheel 5, the traveling condition calculation unit 63 calculates the vehicle body speed Vx based on the slowest rotational speed among the rotational speeds Vw of each wheel 5. Furthermore, when a braking force is being applied to each wheel 5, the traveling condition calculation unit 63 calculates the vehicle body speed Vx based on the fastest rotational speed among the rotational speeds Vw of each wheel 5. When calculating the vehicle body speed Vx, a limit may be placed on the amount of change in the vehicle body speed Vx over time. For example, an upper limit αup of the increase gradient of the vehicle body speed Vx and a lower limit αdn of the decrease gradient of the vehicle body speed Vx may be set, and the change in the vehicle body speed Vx may be restricted by the upper limit αup and the lower limit αdn.

[0045] The method for calculating the vehicle speed Vx is not limited to the above example, and any calculation method, including a conventionally known method, may be used.

[0046] Next, the running condition calculation unit 63 calculates a slip state that indicates the degree of grip of the wheels 5 with respect to the road surface based on the vehicle body speed Vx and the wheel rotation speed Vw (step S19). For example, the running condition calculation unit 63 calculates a deceleration slip speed hV (hV=Vx-Vw) that is the deviation between the vehicle body speed Vx and the rotation speed Vw of each wheel 5 as a state quantity that indicates the slip state. Furthermore, the running condition calculation unit 63 may calculate a wheel slip ratio Sw (Sw=hV / Vx) that is obtained by non-dimensionalizing the deceleration slip speed hV using the vehicle body speed Vx as a state quantity that indicates the slip state.

[0047] Next, the anti-skid control unit 65 determines whether or not to execute anti-skid control based on information about the traveling state of the vehicle 1 (step S21). For example, the anti-skid control unit 65 determines whether or not the vehicle 1 is braking based on at least one of the brake pedal operation amount Ba and the required deceleration Gr. The required deceleration Gr is a deceleration command value from automatic driving control or other driving assistance functions, and is obtained from the control device that manages each function. Furthermore, when at least one of the following conditions is met and it is determined that the vehicle 1 is braking: the brake pedal operation amount Ba is equal to or greater than a predetermined value, the operation signal St is in an ON state, and the required deceleration Gr is equal to or greater than a predetermined value, the anti-skid control unit 65 permits the execution of anti-skid control for each wheel 5.

[0048] If the anti-skid control unit 65 does not determine to execute anti-skid control (S21 / No), the process returns to step S15, and calculation of the running state of the vehicle 1 and determination of whether or not to execute anti-skid control are repeated.

[0049] On the other hand, when the anti-skid control unit 65 determines that anti-skid control is to be performed (S21 / Yes), it repeats the process of reducing the brake pressure when the rotation speed Vw of the wheel 5 for which anti-skid control is to be performed falls to a predetermined lower limit, and increasing the brake pressure when the rotation speed Vw of the wheel 5 rises to a predetermined upper limit, thereby controlling the brake pressure within the range between the upper limit and the lower limit.

[0050] Next, the longitudinal force difference calculation unit 67 calculates the longitudinal force difference ΔFx_f between the left and right front wheels 5F and the longitudinal force difference ΔFx_r between the left and right rear wheels based on the longitudinal force Fx generated in each wheel 5 (step S23).

[0051] Next, the target running state calculation unit 69 calculates a target yaw rate Yr_tgt and a target vehicle body angular acceleration α_tgt according to the running state of the vehicle 1 (step S25). For example, the target running state calculation unit 69 calculates the target yaw rate Yr_tgt using a predetermined stabilization factor set in advance based on the steering angle θs and the vehicle body speed Vx. The stabilization factor A is set in advance using the following equation (1) based on the vehicle body weight W, cornering stiffness Kf, Kr, the shortest distances Lf, Lr from the center of gravity of the vehicle body to the front and rear axles, respectively, and the distance l between the front and rear wheels.

[0052]

number

[0053] W: Vehicle weight K f : Front wheel cornering stiffness K r : Rear wheel cornering stiffness L f : The shortest distance between the vehicle's center of gravity and the front axle L r : The shortest distance between the vehicle's center of gravity and the rear axle l: Distance between front and rear axles

[0054] The target running state calculation unit 69 calculates the steering angle θs, the vehicle weight W, the cornering stiffness K f ,K r , the shortest distance L from the center of gravity of the vehicle body to the front and rear wheel axles f ,L r The target vehicle body angular acceleration α_tgt is calculated based on the above.

[0055] Cornering Stiffness K f ,K rindicates the rise gradient of the cornering force relative to the sideslip angle in the range of very small sideslip angles. Cornering stiffness K f ,K r , vehicle weight W and shortest distance L f ,L r are stored in advance in the storage unit 53 or the like as information on the specifications of the vehicle 1.

[0056] Next, the vehicle body behavior stabilization control unit 71 calculates a yaw rate deviation ΔYr and a vehicle body angular acceleration deviation Δα (step S27). The yaw rate deviation ΔYr is the deviation between the target yaw rate Yr_tgt and the actual yaw rate Yr, and the vehicle body angular acceleration deviation Δα is the deviation between the target vehicle body angular acceleration α_tgt and the actual vehicle body angular acceleration α. ​​The actual vehicle body angular acceleration α is calculated, for example, by dividing the yaw moment of the vehicle body, which is calculated based on the longitudinal force Fx and lateral force Fy generated on each wheel 5, the toe angle θ of each wheel 5, the tread length LT, and the shortest distance L from the center of gravity of the vehicle body to the axle, by the inertia of the vehicle body.

[0057] Next, the vehicle body behavior stabilization control section 71 suppresses the braking force based on the calculated yaw rate deviation ΔYr and vehicle body angular acceleration deviation Δα, and executes processing to stabilize the running state (step S29).

[0058] FIG. 5 shows a flowchart of the vehicle body behavior stabilization process according to this embodiment. First, the vehicle body behavior stabilization control unit 71 determines whether or not the yaw rate deviation ΔYr exceeds a predetermined first threshold value ΔYr_thr (step S41). The first threshold value ΔYr_thr is set in advance to any appropriate value depending on the inertia of the vehicle 1. Since the yaw rate is expressed as a function of the steering angle and the vehicle body speed, the first threshold value ΔYr_thr may be a variable value depending on the vehicle body speed Vx.

[0059] When the vehicle body behavior stabilization control unit 71 determines that the yaw rate deviation ΔYr exceeds the predetermined first threshold ΔYr_thr (S41 / Yes), it calculates a control intervention amount gain based on the vehicle body angular acceleration deviation Δα, and further multiplies the calculated gain by a correction gain according to the yaw rate deviation ΔYr to determine the control intervention amount gain (step S43). The value of the control intervention amount gain based on the vehicle body angular acceleration deviation Δα is determined by referring to pre-set map information, for example, so that the vehicle body angular acceleration deviation Δα equal to or less than a certain value can be quickly converged to suppress the vehicle body behavior from the initial stage. The correction gain according to the yaw rate deviation ΔYr is determined by referring to pre-set map information, for example, so that the vehicle body behavior is gentler, in order to prevent the intervention amount from becoming too large and the vehicle body behavior from becoming erratic.

[0060] On the other hand, when the vehicle body behavior stabilization control unit 71 does not determine that the yaw rate deviation ΔYr exceeds the predetermined first threshold ΔYr_thr (S41 / No), it determines whether the vehicle body angular acceleration deviation Δα exceeds a predetermined second threshold Δα_thr (step S45). The second threshold Δα_thr is set in advance based on the detection errors of the longitudinal force Fx and the lateral force Fy of each wheel 5 and the vehicle moment of inertia. The second threshold Δα_thr may be a variable value that varies depending on the vehicle body speed Vx.

[0061] When the vehicle body behavior stabilization control unit 71 does not determine that the vehicle body angular acceleration deviation Δα exceeds the predetermined second threshold value Δα_thr (S45 / No), it exits the routine without adjusting the brake pressure. On the other hand, when the vehicle body behavior stabilization control unit 71 determines that the vehicle body angular acceleration deviation Δα exceeds the predetermined second threshold value Δα_thr (S45 / Yes), it determines a control intervention amount gain based on the vehicle body angular acceleration deviation Δα (step S47). The value of the control intervention amount gain based on the vehicle body angular acceleration deviation Δα is determined by referring to the map information described above, etc.

[0062] After determining the control intervention amount gain in steps S43 and S45, the vehicle body behavior stabilization control unit 71 limits the braking force of the wheel 5 in a high friction state by a load amount obtained by multiplying the control intervention amount gain by the difference between the left and right longitudinal forces of the front wheels 5F or the rear wheels 5R (step S49). For example, the vehicle body behavior stabilization control unit 71 determines the amount of suppression of the braking force to be limited by multiplying the control intervention amount gain by the difference between the left and right longitudinal forces ΔFx_f of the front wheels 5F. Furthermore, the vehicle body behavior stabilization control unit 71 subtracts the braking force to be limited from the braking force set for the wheel 5 in a high friction state by processing of the anti-skid control unit 65, and calculates the corrected braking force.

[0063] Next, the vehicle body behavior stabilization control unit 71 adjusts the brake pressure according to the corrected braking force (step S51). For example, the vehicle body behavior stabilization control unit 71 sets a target brake pressure by referring to map information that defines the relationship between braking force (braking torque) and brake pressure, and controls the driving of the hydraulic control unit 20 to reduce the brake pressure supplied to the wheels in a high friction state. This reduces the actual yaw rate Yr of the vehicle body and the actual vehicle body angular acceleration α caused by the longitudinal force difference occurring in the front wheel 5F or the rear wheel 5R.

[0064] 4, while executing the vehicle body behavior stabilization process, the vehicle body behavior stabilization control unit 71 determines whether the yaw rate deviation ΔYr is equal to or smaller than the first threshold value ΔYr_thr and whether the vehicle body angular acceleration deviation Δα is equal to or smaller than the second threshold value Δα_thr (step S31). If the yaw rate deviation ΔYr exceeds the first threshold value ΔYr_thr or the vehicle body angular acceleration deviation Δα exceeds the second threshold value Δα_thr (S31 / No), the vehicle body behavior stabilization control unit 71 returns to step S29 and continues the vehicle body behavior stabilization process.

[0065] On the other hand, if the vehicle body behavior stabilization control unit 71 determines that the yaw rate deviation ΔYr is equal to or less than the first threshold ΔYr_thr and that the vehicle body angular acceleration deviation Δα is equal to or less than the second threshold Δα_thr (S31 / Yes), it determines whether the lateral forces Fy of the left and right rear wheels 5R are on an increasing trend (step S33). For example, the vehicle body behavior stabilization control unit 71 determines whether the differential values ​​dFy / dt of the lateral forces Fy of the left and right rear wheels 5R are equal to or less than a third threshold dFy / dt_thr. The vehicle body behavior stabilization control unit 71 may also determine whether the ratio Fy / Fz of the lateral forces Fy of the left and right rear wheels 5R to the ground reaction force Fz is equal to or greater than a predetermined fourth threshold.

[0066] If the lateral force Fy of the rear wheels 5R does not tend to increase even after the control intervention of the vehicle body behavior stabilization process, there is a risk that the behavior of the vehicle body will still become unstable. Therefore, if the vehicle body behavior stabilization control unit 71 does not determine that the lateral forces Fy of the left and right rear wheels 5R are tending to increase (S33 / No), it returns to step S29 and continues the vehicle body behavior stabilization process. On the other hand, if the vehicle body behavior stabilization control unit 71 determines that the lateral forces Fy of the left and right rear wheels 5R are tending to increase (S33 / Yes), it stops the vehicle body behavior stabilization process (step S35).

[0067] Thereafter, the processing unit 51 determines whether the ignition switch is turned off (step S37), and if the ignition switch is not turned off (S37 / No), the processing returns to step S15 and repeats the processing of each step described above. On the other hand, if the ignition switch is turned off (S37 / Yes), the processing unit 51 ends the series of processes.

[0068] <4. Effect> Next, the operation when the vehicle body behavior stabilization process according to this embodiment is executed will be described.

[0069] Figure 6 shows a schematic diagram of the longitudinal forces Fx (Fx_L, Fx_R) of the left and right front wheels 5LF, 5RF, the lateral forces Fy (Fy_L, Fy_R), the friction coefficients μ (μ_L, μ_R) between the left and right front wheels 5LF, 5RF and the road surface, the slip ratios Sw (Sw_L, Sw_R) of the left and right front wheels 5LF, 5RF, the yaw rate deviation ΔYr of the vehicle body, and the angular acceleration deviation Δα of the vehicle body over time when anti-skid control is being performed.

[0070] The example shown in FIG. 6 is a case where the left wheel enters a high friction state while the vehicle 1 is traveling straight and the driver applies the brakes hard, causing anti-skid control to be executed, and this example shows a case where the steering angle θs is assumed to be zero.

[0071] At time t0, anti-skid control begins. Between time t0 and time t1, the friction coefficients μ_L and μ_R of the left and right front wheels 5LF and 5RF are equal. During this time, the anti-skid control unit 65 adjusts the braking force so that the slip ratios Sw_L and Sw_R of the left and right front wheels 5LF and 5RF fall within a predetermined range. Accordingly, the longitudinal forces Fx_L and Fx_R of the left and right front wheels 5LF and 5RF repeatedly increase and decrease. Note that while the friction coefficients μ_L and μ_R of the left and right front wheels 5LF and 5RF are equal, the lateral forces Fy_L and Fy_R of the left and right front wheels 5LF and 5RF are equal.

[0072] At time t1, when the friction coefficient μ_L of the left front wheel 5LF increases, the longitudinal force Fx_L of the left front wheel 5LF begins to increase. At this time, in conventional anti-skid control, the braking force is adjusted so that the slip ratio Sw_L of the left front wheel 5LF continues to fall within a predetermined range, and the longitudinal force Fx_L of the left front wheel 5LF repeatedly increases and decreases while remaining larger than the longitudinal force Fx_R of the right front wheel 5RF. Furthermore, the lateral forces Fy_L and Fy_R generated at the left and right front wheels 5LF and 5RF decrease. At this time, the lateral force Fy_L of the left front wheel 5LF, which has a larger friction coefficient μ_L, becomes larger than the lateral force Fy_R of the right front wheel 5RF. In conventional anti-skid control, the vehicle yaw rate deviation ΔYr, which is the difference between the target yaw rate Yr_tgt (zero in the example shown in FIG. 6 ) and the actual yaw rate Yr, increases. Furthermore, a vehicle body angular acceleration deviation Δα occurs, which is the difference between the target vehicle body angular acceleration α_tgt (zero in the example shown in FIG. 6) and the actual vehicle body angular acceleration α.

[0073] On the other hand, the brake control device 50 according to this embodiment reduces the braking force of the left front wheel 5LF in accordance with the longitudinal force difference ΔFx_f between the left and right front wheels 5F when, at time t1, the friction coefficient μ_L of the left front wheel 5LF increases and the longitudinal force Fx_L_rev of the left front wheel 5LF begins to increase, and then, when the vehicle body yaw rate deviation ΔYr_rev exceeds a predetermined first threshold ΔYr_thr or the vehicle body angular acceleration deviation Δα_rev exceeds a second threshold Δα_thr, the brake control device 50 reduces the braking force of the left front wheel 5LF in accordance with the longitudinal force difference ΔFx_f between the left and right front wheels 5F. As a result, the slip ratio Sw_L_rev of the left front wheel 5LF falls below the range of slip ratios maintained by anti-skid control, and the increase in the longitudinal force Fx_L_rev of the left front wheel 5LF is suppressed. As a result, the vehicle body yaw rate deviation ΔYr and the vehicle body angular acceleration deviation Δα decrease, and the lateral forces Fy_L, Fy_R of the left and right front wheels 5LF, 5RF return to their original state. In this case, the lateral forces Fy_L and Fy_R of the left and right front wheels 5LF and 5RF have equal values.

[0074] In this way, the vehicle brake control device 50 according to this embodiment reduces the braking force of the wheel in the high friction state when the left wheel 5LF is in a high friction state during anti-skid control execution, causing the yaw rate deviation ΔYr to exceed the first threshold value ΔYr_thr or the vehicle body angular acceleration deviation Δα to exceed the second threshold value Δα_thr. This makes it possible to bring the slip ratios of the left and right wheels closer together and stabilize the behavior of the vehicle body even when the friction states of the left and right wheels are different.

[0075] <5. Effects> As described above, the vehicle braking control device 50 according to this embodiment includes one or more processors and one or more memories communicably connected to the one or more processors, and the one or more processors set the target yaw rate Yr_tgt and the target vehicle body angular acceleration α_tgt during anti-skid control, calculate the longitudinal force difference ΔFx between the left and right wheels based on the longitudinal force Fx of each wheel 5 detected by the tire force sensor 8 during anti-skid control, and calculate the actual yaw rate Yr and the actual longitudinal force difference ΔFx based on the longitudinal force difference ΔFx of the left and right wheels. The system is configured to calculate a vehicle body angular acceleration α, and when the yaw rate deviation ΔYr, which is the difference between the target yaw rate Yr_tgt and the actual yaw rate Yr, is equal to or greater than a predetermined first threshold ΔYr_thr, or when the vehicle body angular acceleration deviation Δα, which is the difference between the target vehicle body angular acceleration α_tgt and the actual vehicle body angular acceleration α, is equal to or greater than a predetermined second threshold Δα_thr, suppress the braking force applied to either the left or right wheel, and keep the yaw rate deviation ΔYr and the vehicle body angular acceleration deviation Δα within a predetermined range (less than the first threshold ΔYr_thr, less than the second threshold Δα_thr).

[0076] Therefore, the braking control device 50 directly detects the longitudinal force difference ΔFx between the left and right wheels 5 measured using the tire force sensors 8 provided on each wheel 5, and suppresses the braking force of the wheel in a high friction state, thereby directly controlling the amount of yaw moment generated in the vehicle body. This eliminates the need for processing to estimate the friction coefficient of the road surface, and makes it possible to quickly detect the longitudinal force difference ΔFx between the left and right wheels and quickly approximate the slip ratio, thereby shortening the free-running time after the longitudinal force difference ΔFx between the left and right wheels occurs. This reduces the risk of the vehicle body's behavior becoming unstable.

[0077] Furthermore, in the braking control device 50 of the vehicle according to this embodiment, the one or more processors stop suppressing the braking force applied to either the left or right wheel when the lateral force Fy of the left or right rear wheel 5R begins to trend upward after the yaw rate deviation ΔYr and the vehicle body angular acceleration deviation Δα have been brought within a predetermined range. Therefore, the braking control device 50 can directly control the amount of yaw moment generated in the vehicle body until the behavior of the vehicle body is reliably stabilized, while directly monitoring the lateral force Fy of the rear wheel 5R using the tire force sensor 8R.

[0078] <6. Other embodiments> In the above embodiment, when the yaw rate deviation ΔYr is equal to or greater than a predetermined first threshold ΔYr_thr or the vehicle body angular acceleration deviation Δα is equal to or greater than a predetermined second threshold Δα_thr, the braking control device 50 suppresses the braking force applied to one of the left and right wheels to keep the yaw rate deviation ΔYr and the vehicle body angular acceleration deviation Δα within a predetermined range. However, the method of approximating the slip ratios of the left and right wheels where the longitudinal force difference ΔFx has occurred is not limited to the method of suppressing the braking force of the wheel in a high friction state, and may also be a method of increasing the driving force of the wheel in a low friction state.

[0079] A braking control device 50 according to another embodiment is applied to, for example, an electric vehicle equipped with a drive motor (in-wheel motor) for each wheel 5. In this case, the vehicle body behavior stabilization control unit 71 increases the output of the drive motor that drives the wheel 5 in a low friction state based on the yaw rate deviation ΔYr and the vehicle body angular acceleration deviation Δα, thereby increasing the drive force of the wheel 5 and stabilizing the running state.

[0080] FIG. 7 shows a flowchart of a vehicle body behavior stabilization process according to another embodiment. First, the vehicle body behavior stabilization control section 71 determines whether or not the yaw rate deviation ΔYr exceeds the predetermined first threshold value ΔYr_thr, similarly to step S41 in FIG. 5 (step S61).

[0081] When the vehicle body behavior stabilization control unit 71 determines that the yaw rate deviation ΔYr exceeds a predetermined first threshold ΔYr_thr (S61 / Yes), the vehicle body behavior stabilization control unit 71 calculates a control intervention amount gain based on the vehicle body angular acceleration deviation Δα, and further multiplies the calculated control intervention amount gain by a correction gain corresponding to the yaw rate deviation ΔYr (step S63). The value of the control intervention amount gain based on the vehicle body angular acceleration deviation Δα is determined by referring to pre-set map information, for example, so that the vehicle body angular acceleration deviation Δα below a certain level can be quickly converged to suppress the vehicle body behavior from the initial stage. The correction gain corresponding to the yaw rate deviation ΔYr is determined by referring to pre-set map information, for example, so that the vehicle body behavior is gentler, in order to prevent the intervention amount from becoming too large and the vehicle body behavior from becoming too drastic. Note that the control intervention amount gain and the correction gain may be values ​​different from the control intervention amount gain and the correction gain for suppressing the braking force used in the above-described embodiment.

[0082] On the other hand, if the vehicle body behavior stabilization control unit 71 does not determine that the yaw rate deviation ΔYr exceeds the predetermined first threshold value ΔYr_thr (S61 / No), it determines whether the vehicle body angular acceleration deviation Δα exceeds the predetermined second threshold value Δα_thr (step S65), similar to step S45 in Figure 5.

[0083] If the vehicle body behavior stabilization control unit 71 does not determine that the vehicle body angular acceleration deviation Δα exceeds the predetermined second threshold value Δα_thr (S65 / No), the vehicle body behavior stabilization control unit 71 exits the routine without adjusting the driving force. On the other hand, if the vehicle body angular acceleration deviation Δα exceeds the predetermined second threshold value Δα_thr (S65 / Yes), the vehicle body behavior stabilization control unit 71 determines a control intervention amount gain based on the vehicle body angular acceleration deviation Δα (step S67). The value of the control intervention amount gain based on the vehicle body angular acceleration deviation Δα is determined by referring to the map information described above, etc.

[0084] After determining the control intervention amount gain in steps S63 and S65, the vehicle body behavior stabilization control unit 71 increases the driving force of the wheel 5 in the low friction state by the load calculated by multiplying the control intervention amount gain by the difference in longitudinal force between the left and right of the front wheels 5F or the rear wheels 5R (step S69). For example, the vehicle body behavior stabilization control unit 71 obtains the increase in driving force by multiplying the control intervention amount gain by the difference in longitudinal force between the left and right of the front wheels 5F. The vehicle body behavior stabilization control unit 71 also sets the calculated driving force as the driving force to be generated at the wheel 5 in the low friction state by processing of the anti-skid control unit 65.

[0085] Next, the vehicle body behavior stabilization control unit 71 transmits information about the set driving force to the driving force source control device 21 and adjusts the output of the drive motor that drives the wheels in the low-friction state (step S71). The driving force source control device 21 controls the drive of an inverter (not shown) to output the commanded driving force from the drive motor that drives the wheels in the low-friction state. This reduces the actual yaw rate Yr of the vehicle body and the actual vehicle body angular acceleration α caused by the longitudinal force difference generated in the front wheels 5F or the rear wheels 5R.

[0086] As described above, the vehicle braking control device 50 according to another embodiment includes one or more processors and one or more memories communicably connected to the one or more processors, and the one or more processors set the target yaw rate Yr_tgt and the target vehicle body angular acceleration α_tgt during anti-skid control, calculate the longitudinal force difference ΔFx between the left and right wheels based on the longitudinal force Fx of each wheel 5 detected by the tire force sensor 8 during anti-skid control, and calculate the actual yaw rate Yr and the actual yaw rate ΔFx based on the longitudinal force difference ΔFx of the left and right wheels. The system is configured to calculate a vehicle body angular acceleration α, and when the yaw rate deviation ΔYr, which is the difference between the target yaw rate Yr_tgt and the actual yaw rate Yr, is equal to or greater than a predetermined first threshold ΔYr_thr, or when the vehicle body angular acceleration deviation Δα, which is the difference between the target vehicle body angular acceleration α_tgt and the actual vehicle body angular acceleration α, is equal to or greater than a predetermined second threshold Δα_thr, increase the driving force applied to either the left or right wheel to keep the yaw rate deviation ΔYr and the vehicle body angular acceleration deviation Δα within a predetermined range (less than or equal to the first threshold ΔYr_thr or less than or equal to the second threshold Δα_thr).

[0087] Therefore, the braking control device 50 directly detects the longitudinal force difference ΔFx between the left and right wheels 5 measured using the tire force sensors 8 provided on each wheel 5, and increases the driving force of the wheel in a low friction state, thereby directly controlling the amount of yaw moment generated in the vehicle body. This eliminates the need for processing to estimate the friction coefficient of the road surface, and makes it possible to quickly detect the longitudinal force difference ΔFx between the left and right wheels and quickly approximate the slip ratio, thereby shortening the free-running time after the longitudinal force difference ΔFx between the left and right wheels occurs. This reduces the risk of the vehicle body's behavior becoming unstable.

[0088] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art to which the present disclosure pertains can conceive of various modifications or alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0089] In addition, the technology disclosed herein can also be realized as a vehicle equipped with the braking control device described in the above embodiments, a braking control method using the braking control device, a program that causes a computer to function as the above-mentioned braking control device, and a non-temporary tangible recording medium on which the program is recorded. [Explanation of symbols]

[0090] 1: Vehicle 4: Axle 5: Wheels 8: Tire force sensor 9: Wheel speed sensor 11: Steering angle sensor 13: Brake sensor 15: Yaw rate sensor 20: Hydraulic control unit 50: Braking control device 51: Processing section 53: Storage section 61: Acquisition part 63: Driving state calculation unit 65: Anti-skid control unit 67: Front and rear force difference calculation section 69: Target driving state calculation unit 71: Vehicle behavior stabilization control unit

Claims

1. In a vehicle braking control device that performs anti-skid control, one or more processors; and one or more memories communicatively coupled to the one or more processors; the one or more processors: setting a target yaw rate and a target vehicle body angular acceleration during the anti-skid control; calculating a difference between longitudinal forces of the left and right wheels based on longitudinal forces of each wheel detected by a tire force sensor during the anti-skid control; calculating an actual yaw rate and an actual vehicle body angular acceleration based on a longitudinal force difference between the left and right wheels; When a yaw rate deviation, which is a difference between the target yaw rate and the actual yaw rate, exceeds a predetermined first threshold value, or when a vehicle body angular acceleration deviation, which is a difference between the target vehicle body angular acceleration and the actual vehicle body angular acceleration, exceeds a predetermined second threshold value, the braking force applied to one of the left and right wheels is reduced or the driving force is increased, so that the yaw rate deviation and the vehicle body angular acceleration deviation are within a predetermined range; A vehicle braking control device that performs the above.

2. the one or more processors: When the yaw rate deviation exceeds the predetermined first threshold value, the amount of suppression of the braking force or the amount of increase of the driving force is set based on the value of the yaw rate deviation and the value of the vehicle body angular acceleration deviation. The vehicle brake control device according to claim 1.

3. the one or more processors: When the yaw rate deviation is equal to or smaller than the predetermined first threshold value and the vehicle body angular acceleration deviation exceeds the predetermined second threshold value, the amount of suppression of the braking force or the amount of increase of the driving force is set based on the value of the vehicle body angular acceleration deviation. The vehicle brake control device according to claim 1.

4. the one or more processors: When the lateral forces of the left and right rear wheels tend to increase after the yaw rate deviation and the vehicle body angular acceleration deviation are brought within a predetermined range, the braking force applied to one of the left and right wheels is reduced or the increase in the driving force is stopped. The vehicle brake control device according to claim 1.

5. The computer setting a target yaw rate and a target vehicle body angular acceleration during anti-skid control; calculating a difference in longitudinal forces between the left and right front wheels and a difference in longitudinal forces between the left and right rear wheels based on the longitudinal forces of each wheel detected by a tire force sensor during the anti-skid control; calculating a yaw rate and a vehicle body angular acceleration based on the longitudinal force difference between the left and right front wheels and the longitudinal force difference between the left and right rear wheels; When a yaw rate deviation, which is the difference between the target yaw rate and the yaw rate, is equal to or greater than a predetermined first threshold value, or when a vehicle body angular acceleration deviation, which is the difference between the target vehicle body angular acceleration and the vehicle body angular acceleration, is equal to or greater than a predetermined second threshold value, reducing the braking force applied to either the left or right wheel of at least one of the front wheels and the rear wheels or increasing the driving force, thereby keeping the yaw rate deviation and the vehicle body angular acceleration deviation within a predetermined range; A vehicle braking control method for performing the above.

6. On the computer, setting a target yaw rate and a target vehicle body angular acceleration during anti-skid control; calculating a lateral force difference between the left and right front wheels and a lateral force difference between the left and right rear wheels based on the lateral forces of the respective wheels detected by the tire force sensors during the anti-skid control; calculating a yaw rate and a vehicle body angular acceleration based on the lateral force difference between the left and right front wheels and the lateral force difference between the left and right rear wheels; When a yaw rate deviation, which is the difference between the target yaw rate and the yaw rate, is equal to or greater than a predetermined first threshold value, or when a vehicle body angular acceleration deviation, which is the difference between the target vehicle body angular acceleration and the vehicle body angular acceleration, is equal to or greater than a predetermined second threshold value, reducing the braking force applied to either the left or right wheel of at least one of the front wheels and the rear wheels or increasing the driving force, thereby keeping the yaw rate deviation and the vehicle body angular acceleration deviation within a predetermined range; A computer program that executes

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