Vehicle control device, vehicle control method and vehicle control system

Abstract

To provide a vehicle control device, a vehicle control method and a vehicle control system capable of suppressing pitching fluctuation when a vehicle is stopped.SOLUTION: In a vehicle control device, a vehicle control method and a vehicle control system in one embodiment, a physical quantity relative to vehicle speed, and a physical quantity relative to required braking force required for decelerating the vehicle are acquired, and when the vehicle is decelerated based on the physical quantity relative to the required braking force, in the state where frictional braking force is generated, driving force by a driving device is generated.SELECTED DRAWING: Figure 16

Description

[Technical Field]

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

[0002] Patent document 1 discloses a vehicle longitudinal vibration control device that sets the torque reduction start vehicle speed, at which the vehicle longitudinal acceleration when the vehicle transitions from a deceleration state to zero vehicle speed is below a predetermined allowable value, based on the regenerative braking force during regenerative braking, the final target value of the motor braking / driving force, and a predetermined reduction gradient for reducing the regenerative braking force. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-28913 Summary of the Invention

[0004] However, in Patent Document 1, the regenerative braking force is reduced in accordance with the decrease in vehicle speed, so there was a risk that pitching fluctuations would occur when the vehicle was stopped due to control errors based on the estimation of the gradient of the decrease in the regenerative braking force. An object of the present invention is to provide a vehicle control device, a vehicle control method, and a vehicle control system that can suppress pitching fluctuations when the vehicle is stopped. [Means for solving the problem]

[0005] In one embodiment of the present invention, a vehicle control device, a vehicle control method, and a vehicle control system acquire a physical quantity related to the vehicle speed and a physical quantity related to the required braking force required to stop the vehicle, and generate a driving force from the drive device while a frictional braking force is being generated, just before the vehicle stops, based on the physical quantity related to the required braking force. [Effects of the Invention]

[0006] According to the present invention, pitching fluctuations can be suppressed when the vehicle is stopped. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a configuration diagram of a control system for an electric vehicle according to a first embodiment. [Figure 2] FIG. 2 is a control block diagram showing a driving torque calculation process of the vehicle control device in the first embodiment. [Figure 3] FIG. 3 is a control block diagram showing details of a driver-requested torque calculation process in the first embodiment. [Figure 4] FIG. 3 is a control block diagram showing details of a gradient resistance calculation unit in the first embodiment. [Figure 5] 4 is a diagram illustrating the operation of a vehicle stop determination unit in the first embodiment. FIG. [Figure 6] 10 is a forgetting gain map provided in a vehicle stop information storage unit in the first embodiment. [Figure 7] 4 is a gradient correction torque map provided in a gradient resistance calculation unit in the first embodiment. [Figure 8] FIG. 4 is a control block diagram showing details of a gradient resistance and braking force request equivalent torque calculation unit in the first embodiment. [Figure 9] FIG. 3 is a control block diagram showing details of a control gain calculation unit and an additional torque calculation unit in the first embodiment. [Figure 10] 4 is a variable acceleration control gain map according to the first embodiment. [Figure 11] 4 is a speed variable control gain map according to the first embodiment. [Figure 12] FIG. 3 is a control block diagram illustrating details of a gain hold time adjustment unit in the first embodiment. [Figure 13] 4 is a time chart showing the operation of the gain hold time adjustment unit in the first embodiment. [Figure 14] FIG. 3 is a control block diagram illustrating details of a control gain rate limiting unit in the first embodiment. [Figure 15]10 is a time chart showing a gain characteristic when the vehicle speed is decreasing. [Figure 16] 4 is a time chart showing a change in vehicle speed when a driver request torque calculation process is performed in the first embodiment. [Figure 17] 10A and 10B are diagrams showing experimental results when the present control is applied to an actual vehicle and when it is not applied. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Embodiment 1] FIG. 1 is a configuration diagram of a control system for an electric vehicle according to the first embodiment. The electric vehicle 1 has front wheels 2FL, 2FR and rear wheels 2RL, 2RR, and friction brakes 3FL, 3FR, 3RL, 3RR (hereinafter, the friction brakes of each wheel will be collectively referred to as friction brake 3) that are provided on each wheel and generate friction braking force on the wheel. The electric vehicle 1 has a rear motor (rear wheel electric motor) 7 that outputs torque to rear wheels 2RL and 2RR. The rear wheels 2RL and 2RR are also collectively referred to as drive wheels 2. Power is transmitted between the rear motor 7 and the rear wheels 2RL and 2RR via a reduction gear 8, a differential 10, and rear axles 6RL and 6RR. Each of the wheels 2FL, 2FR, 2RL, and 2RR has a wheel speed sensor 11FL, 11FR, 11RL, and 11RR that detects the wheel speed. The rear motor 7 has a rear wheel resolver 13 that detects the motor rotation speed. The electric vehicle 1 also has an acceleration sensor 5 that detects the vehicle acceleration. The friction brake 3 generates a braking force by pressing brake pads against brake rotors that rotate integrally with each wheel in the direction of the rotation axis of the wheel through frictional force. The friction brake 3 in the first embodiment is described as being configured to press the brake pads using wheel cylinders that are actuated by brake fluid pressure, but is not particularly limited and may be configured to press the brake pads via a ball screw mechanism or the like driven by an electric motor. The electric vehicle 1 has a low-voltage battery 14 and a high-voltage battery 15. The low-voltage battery 14 is, for example, a lead-acid battery. The high-voltage battery 15 is, for example, a lithium-ion battery or a nickel-metal hydride battery. The high-voltage battery 15 is charged with power boosted by a DC-DC converter 16.

[0009] The electric vehicle 1 has a vehicle control device 17, a brake control device 18, a rear motor control device 20, and a battery control device 19. The control devices 17, 18, and 20 share information with each other via a CAN bus 21. The vehicle control device 17 performs integrated control of the vehicle by acquiring information from various sensors such as the rear wheel resolver 13, an accelerator pedal sensor 22 that detects the amount of accelerator operation, a brake sensor 23 that detects the amount of brake operation, and a gear position sensor 24. The vehicle control device 17 outputs a driver-requested torque that should be output by the rear motor 7 in accordance with the requested distribution torque in response to the requested torque according to the driver's accelerator operation, brake operation, etc. The brake control device 18 acquires information from various sensors such as the acceleration sensor 5 and the wheel speed sensor 11, and calculates the friction brake torque to be generated in the friction brake 3 based on the torque required by the driver, generates the required brake fluid pressure for each wheel, and outputs it to the friction brake 3 through hydraulic piping 18a.

[0010] The battery control device 19 monitors the charge / discharge state of the high-voltage battery 15 and the single battery cells that make up the high-voltage battery 15. The battery control device 19 calculates a battery required torque limit value based on the charge / discharge state of the high-voltage battery 15. The battery required torque limit value is the maximum torque permitted in the rear motor 7. For example, when the charge level of the high-voltage battery 15 is low, the battery required torque limit value is set to a value smaller than normal. The rear motor control device 20 controls the power supplied to the rear motor 7 based on the rear required torque.

[0011] FIG. 2 is a control block diagram showing the driving torque calculation process of the vehicle control device 17 in the first embodiment. The driver required torque calculation processing unit 101 calculates the driver required torque based on the vehicle speed, accelerator operation amount, and vehicle acceleration. When the driver releases the accelerator pedal and the vehicle speed is equal to or higher than a predetermined vehicle speed, a coast torque, which is a negative torque simulating engine braking force, is output, and when the vehicle speed is in the low vehicle speed range, a creep torque, which is a positive torque, is output. Details of the calculation in this processing unit will be described later. The vehicle speed is estimated from rotation speed information of the rear motor 7 obtained from the wheel speed sensor 11 and the rear wheel resolver 13, but it may also be calculated from other sensors. The slip control torque calculation processing unit 103 calculates the driving torque limit value during acceleration or the braking torque limit value during deceleration from the vehicle speed, slip control target wheel speed, and driver-requested torque, and calculates the slip control torque limited so that the torque after regenerative cooperative braking is accepted falls within the range of the above limit values. The torque limiting processor 104 limits the slip control torque using various torque limiting values, such as the battery required torque limiting value, and outputs the post-limiting drive torque as the command torque. The post-limiting drive torque includes both the torque on the accelerating side and the torque on the decelerating side of the vehicle.

[0012] FIG. 3 is a control block diagram showing details of the driver requested torque calculation process in the first embodiment. The driver-requested torque calculation unit 201 calculates the torque requested by the driver based on the accelerator operation amount and the vehicle speed. The calculation content is not particularly limited and may be any known technical configuration. The grade resistance calculation unit 202 calculates the resistance acting on the vehicle due to the gradient of the road surface, based on the vehicle speed and the acceleration, which is the value of the acceleration sensor 5. Specifically, the grade is estimated from the deviation between the estimated acceleration calculated from the vehicle speed and the actual acceleration detected by the acceleration sensor 5. This is to prevent the vehicle deceleration from decreasing excessively when torque is added due to the gradient of a downhill slope. The gradient resistance and braking force requirement equivalent torque calculation unit 203 converts this into torque equivalent to the braking force requirement value. Specifically, the gradient resistance equivalent torque and creep torque are subtracted from the braking force requirement equivalent torque value to avoid application of torque that generates a driving force exceeding the braking force. The control gain calculation unit 204 calculates both a gain according to the vehicle speed and a gain according to the deceleration. Specifically, this is to change the peak gain according to the deceleration and increase or decrease the gain according to the vehicle speed when the vehicle is stopped. An additional torque calculation unit 205 multiplies the torque value equivalent to the braking force request by a control gain to calculate an additional torque capable of suppressing vibration in the pitching direction. The adder 206 adds the additional torque output from the additional torque calculation unit 205 to the value output from the driver request torque calculation unit.

[0013] 4 is a control block diagram showing details of the grade resistance calculation unit 202 in embodiment 1. The grade resistance calculation unit 202 has a stationary-state information storage unit 2021, an actual grade estimation unit 2022, a grade estimation correction unit 2023, and a grade correction torque map 2024. The vehicle stop information storage unit 2021 includes a vehicle stop determination unit a1, an acceleration sensor value storage unit a2, a travel distance estimation unit a3, a forgetting gain map a4, a multiplication unit a5, and a deviation calculation unit a6. When the vehicle travels at low speed on a slope and then stops again, the actual slope estimation unit 2022 does not have enough time to estimate the slope, which may result in a decrease in performance. Therefore, the vehicle stop information storage unit 2021 is configured to improve the slope estimation accuracy by using acceleration sensor value information from the previous time the vehicle was stopped. The actual gradient estimation unit 2022 estimates an actual gradient estimate value, which is the current gradient, based on the value output from the acceleration / deceleration estimation unit a7, which calculates the estimated acceleration / deceleration of the vehicle calculated by differentiating the vehicle speed, and the value output from the acceleration sensor 5.

[0014] FIG. 5 is a diagram showing the operation of the vehicle stop determination unit in the first embodiment. The vehicle stop determination unit a1 has a function of determining whether the vehicle has stopped when the vehicle speed falls below a predetermined value and after a predetermined time has passed since the vehicle stopped. The reason for waiting for the predetermined time is that the acceleration sensor value immediately after the vehicle has stopped may be oscillating. The acceleration sensor value storage unit a2 has a function of storing the value of the acceleration sensor 5 after the vehicle stop determination unit a1 determines that the vehicle has stopped. The traveling distance estimation unit a3 calculates the traveling distance from the control cycle time and the vehicle speed.

[0015] FIG. 6 shows a forgetting gain map provided in the vehicle-stop information storage unit in the first embodiment. This map is a gain for gradually forgetting the stored acceleration sensor value according to the travel distance, and the acceleration sensor value is completely forgotten when it reaches a predetermined value x1 (m). A multiplication unit a5 multiplies the stored acceleration sensor value by a forgetting gain according to the travel distance to calculate the acceleration sensor value. A deviation calculation unit a6 calculates the deviation between the actual gradient estimated value calculated by the actual gradient estimation unit 2022 and the gradient stored in the vehicle-stop information value storage unit 2021. The gradient estimation corrector 2023 corrects the actual gradient by adding the value output from the deviation calculator a6 to the actual gradient estimate. Fig. 7 shows a gradient correction torque map provided in the gradient resistance calculator in embodiment 1. If the gradient is an uphill (+), a value corrected to the positive side as the gradient correction torque is output as the gradient correction torque, and if the gradient is a downhill (-), a value corrected to the negative side as the gradient correction torque is output as the gradient correction torque.

[0016] FIG. 8 is a control block diagram showing details of the gradient resistance and braking force request equivalent torque calculation unit in the first embodiment. The gradient resistance and braking force request equivalent torque calculation unit 203 includes a braking force torque conversion unit 2031, an adder 2032, a selector 2033, and a subtractor 2034. The braking force torque conversion unit 2031 calculates a torque equivalent to the braking force generated by braking operation. The adder 2032 adds a gradient correction torque to the torque equivalent to the braking force. The selector 2033 limits the torque equivalent to the braking force request to 0 so that it does not become positive (acceleration). The subtractor 2034 subtracts a creep torque so that the sum of the creep torque and the added torque does not exceed the braking force, preventing an excessive decrease in vehicle deceleration due to inertia on a downhill slope when torque is added. This prevents the vehicle 1 from accelerating unintentionally.

[0017] 9 is a control block diagram showing details of the control gain calculation unit 204 and the additional torque calculation unit 205 in embodiment 1. The control gain calculation unit 204 includes an acceleration estimation value calculation unit 2041, an estimated speed calculation unit 2042, a control gain map (variable acceleration type) 2043, a control gain map (variable speed type) 2044, a multiplication unit 2045, a gain hold time adjustment unit 2046, a multiplication unit 2047, and a control gain rate limit unit 2048. The additional torque calculation unit 205 includes a multiplication unit 2051 and a selection unit 2052. The acceleration estimation value calculation unit 2041 calculates an estimated value of vehicle acceleration from the differential value of the vehicle speed. FIG. 10 shows the acceleration variable control gain map, and FIG. 11 shows the speed variable control gain map. In the acceleration variable control gain map 2043, when deceleration occurs whose absolute value is equal to or greater than a specified value x2 (G), the gain is gradually reduced, and when deceleration whose absolute value is smaller than the specified value x2 (G), the gain is set to 100%, thereby preventing torque from being added during sudden braking. Needless to say, during sudden braking, it is more desirable to ensure braking force than to suppress vibration in the pitching direction. Furthermore, the speed variable control gain map 2044 is a gain that acts to suppress the increase in vehicle speed, and is set to completely 0 when the vehicle speed reaches x3 (km / m), so it mainly acts just before the vehicle stops. In the multiplication unit 2045, these two gains are multiplied together to effectively act just before the vehicle stops, except during sudden deceleration.

[0018] FIG. 12 is a control block diagram showing the details of the gain hold time adjustment unit 2046, and FIG. 13 is a time chart showing the operation of the gain hold time adjustment unit 2046. The gain hold time adjustment unit 2046 has a vehicle stop determination unit b1, a brake ON determination unit b2, a multiplication unit b3, and a predetermined time lapse determination unit b4. The vehicle stop determination unit b1 determines whether the vehicle speed has reached a predetermined value for vehicle stop determination, and outputs 1 if it determines that the vehicle is stopped, and outputs 0 otherwise. The brake ON determination unit b2 outputs 1 if it determines that the brake is depressed or ON, and outputs 0 otherwise. The multiplication unit b3 outputs 1 if it determines that the brake is ON and the vehicle is stopped, and outputs 0 otherwise. The predetermined time lapse determination unit b4 outputs 1 from the multiplication unit b3, and continues to output 1 until a predetermined time has elapsed, and then outputs 0 after the predetermined time has elapsed, thereby maintaining the maximum value so that the gain does not decrease immediately after the vehicle has stopped.

[0019] FIG. 14 is a control block diagram showing the details of the control gain rate limiting unit 2048. The control gain rate limiting unit 2048 includes a deviation calculation unit c1, a minimum rate output unit c2 for gain increase, a selector c3, an output unit c4 for outputting the minimum rate of gain decrease, a selector c5, an adder c6, and a previous value holder c7. The deviation calculation unit c1 calculates the deviation between the gain multiplied by the multiplier 2047 and the limited gain. The selector c3 compares the deviation with the value output from the minimum rate output unit c2 for gain increase and outputs the smaller of the two. This means that the gain is prevented from changing at a rate greater than the minimum rate when the gain increases, resulting in a smooth change. The selector c5 outputs the larger of the value output from the minimum rate output unit c4 for gain decrease or the value output from the selector c3. This means that the gain is prevented from changing at a rate greater than the minimum rate when the gain decreases, resulting in a smooth change.

[0020] 15 is a time chart showing gain characteristics when the vehicle speed is decreasing. The gain output from the control gain map (speed variable type) 2045 is indicated as 2045 gain, the value obtained by multiplying the 2045 gain by the value output from the gain hold time adjustment unit 2046 is indicated as 2047 gain, and the gain obtained by applying the control gain rate limit unit to the 2047 gain is indicated as 2048 gain. Setting a gain according to vehicle speed, such as the 2045 gain, allows for smooth stopping of the vehicle, but the gain continues to be generated even after the vehicle has stopped. Therefore, even while the vehicle is stopped, the rear motor 7 continues to output a torque lower than the torque of the friction brake 3, resulting in excessive power consumption. Next, the 2047 gain allows for smooth stopping and reduces excessive power consumption compared to the 2045 gain. However, sudden gain fluctuations can cause sudden changes in vehicle posture after the vehicle has stopped and torsional resonance of the drive shaft, which can lead to vibrations and discomfort for the driver. In contrast, the 2048 gain limits gain fluctuations, resulting in smoother gain fluctuations than other gains. This can avoid sudden changes in vehicle posture and torsional resonance of the drive shaft, thereby suppressing vibrations and discomfort for the driver.

[0021] The additional torque calculation unit 205 (see FIG. 9) has a multiplication unit 2051 and a selection unit 2052. The multiplication unit 2051 multiplies the braking force request equivalent torque value by the gain output from the control gain rate limit unit 2048 and outputs a limited control gain. The selection unit 2052 compares the braking force request equivalent torque value with the limited braking force request equivalent torque value and outputs the smaller one as the final additional torque.

[0022] Fig. 16 is a time chart showing changes in vehicle speed when the driver-requested torque calculation process in embodiment 1 is performed, and Fig. 17 is a diagram showing experimental results for cases where this control is applied to an actual vehicle and cases where it is not applied. In the torque column in Fig. 16, the dotted line represents the torque that balances with the requested braking force, the dashed-dot line represents the torque in the case where no control is performed and the driver-requested torque calculation process is not performed, and the solid line represents the torque after addition.

[0023] That is, when the vehicle comes to a stop with the driver depressing the brake pedal, the required braking force is calculated as the driver-requested torque based on the state of depression of the brake pedal by the driver. Therefore, a braking force greater than the braking force required to stop the vehicle continues to be applied by the friction brake 3. As a result, the friction coefficient of the friction brake 3 suddenly switches from the dynamic friction coefficient to the static friction coefficient just before the vehicle comes to a stop, which tends to cause a sudden drop in vehicle speed and a sudden change in acceleration (see the square box in the "No Control" acceleration column in Figure 17).

[0024] Therefore, the peak gain is increased or decreased at a timing that coincides with the vehicle stopping, and the output torque from the rear motor 3 is added without changing the braking force of the friction brake 3, and a drive-side torque is applied within a range below the torque at which the friction brake 3 inhibits the rotation of the rear wheels 2RR, RL. This makes it possible to suppress changes in acceleration acting on the vehicle while ensuring the braking force of the friction brake 3 (see the square box in the acceleration column for "with control" in Figure 17). It is also possible to change the braking torque on the friction brake 3 side, but in this case, there is a limit to the responsiveness of mechanical inertia due to the use of friction force, and it is also difficult to ensure control precision due to the influence of variations in the friction coefficient of the brake pads, etc. In contrast, by adding the output torque from the rear motor 3 while ensuring the braking torque of the friction brake 3, torque fluctuations due to changes in the friction coefficient of the friction brake 3, etc., can be suppressed, and pitching vibrations when the vehicle is stopped can be effectively suppressed.

[0025] The control device, control method, and control system for an electric vehicle according to the first embodiment have the following advantages. (1) A vehicle control device is provided on a vehicle (1) having a friction brake (3) (friction braking device) that generates a friction braking force on the vehicle (1) and a rear motor (7) (driving device) that generates a driving force on the vehicle (1), and the vehicle control device is provided with a vehicle control device (17) (control unit) that outputs a result of calculation based on input information, The vehicle control device 17 includes: Obtain a physical quantity related to the speed of vehicle 1, A physical quantity related to a required braking force required to decelerate vehicle 1 is obtained; When the vehicle 1 is decelerated based on the physical quantity related to the required braking force, a control command is output to generate a driving force by the rear motor 7 in a state where a friction braking force is being generated. Therefore, it is possible to suppress a sudden change in vehicle acceleration due to frictional braking force, and to suppress pitching fluctuations when the vehicle is stopped.

[0026] (2) The vehicle control device 17 outputs a control command when a physical quantity related to the speed falls below a predetermined speed, thereby preventing unnecessary torque application during normal deceleration except when the vehicle is stopped. (3) The vehicle control device 17 outputs a control command so that the driving force increases as the physical quantity related to the speed decreases and as the physical quantity related to the deceleration of the vehicle 1 decreases. Therefore, the driving force can be effectively generated immediately before the vehicle stops, except during sudden deceleration. (4) After determining that the vehicle 1 has stopped, the vehicle control device 17 outputs a control command to maintain the maximum value of the driving force until a predetermined time has elapsed. This prevents a sudden change in the torque acting on the drive wheels after the vehicle has stopped. (5) The vehicle control device 17 outputs a control command to gradually decrease the driving force after maintaining the maximum value of the driving force. This prevents sudden changes in the vehicle posture and torsional resonance of the drive shaft, and suppresses vibrations and discomfort felt by the driver.

[0027] (6) The vehicle control device 17 outputs a control command so that the sum of the driving force and the force due to the creep phenomenon occurring in the vehicle 1 does not exceed the friction braking force. This makes it possible to prevent the vehicle 1 from accelerating unintentionally. (7) The vehicle control device 17 outputs the control command so that the driving force decreases as the downhill road gradient increases when decelerating the vehicle 1. This prevents the generation of torque on the acceleration side due to the influence of the road surface.

[0028] (8) The vehicle control device 17 estimates the road surface gradient based on the difference between the differential value of the physical quantity related to the vehicle speed and the sensor value acquired from the acceleration sensor. Therefore, the road surface gradient can be estimated with high accuracy. (9) The vehicle control device 17 estimates the road gradient based on the difference between the differential value of the physical quantity related to the vehicle speed and the sensor value acquired from the acceleration sensor, and the value acquired and stored from the acceleration sensor when the vehicle 1 was stopped on a road gradient. That is, when the vehicle 1 is traveling at a low speed on a sloped road and then stops again, there is a risk that there is not enough time for gradient estimation and performance may be degraded. Therefore, by using the acceleration sensor value information from the previous time the vehicle was stopped, the gradient estimation accuracy can be improved. (10) In the first embodiment, the rear motor 7, which is an electric motor, is provided as a drive device. Therefore, the drive force can be controlled with high control precision and responsiveness, and pitching fluctuations when the vehicle is stopped can be effectively suppressed.

[0029] Other Embodiments The above describes an embodiment for carrying out the present invention, but the specific configuration of the present invention is not limited to the configuration of the embodiment, and design changes and the like that do not deviate from the gist of the invention are also included in the present invention. For example, although the present embodiment is applied to a rear-wheel drive electric vehicle, it may also be applied to a front-wheel drive electric vehicle or a four-wheel drive electric vehicle. Furthermore, it is not limited to electric vehicles, and may also be applied to vehicles equipped with an internal combustion engine or a hybrid vehicle that can run using both an engine and a motor. In other words, it is sufficient if the configuration is such that when the vehicle is stopped using the friction brake, torque can be applied from the drive source within a range that allows the vehicle to stop or within a range that applies braking force between the drive wheels and the road surface.

[0030] [Technical Ideas that can be Grasp from the Examples] The technical ideas (or technical solutions; the same applies hereinafter) that can be understood from the embodiments described above will be described below. (1) In one aspect, the vehicle control device of the present technical idea is as follows: A vehicle control device is provided in a vehicle having a friction braking device that generates a friction braking force in the vehicle and a drive device that generates a drive force in the vehicle, and the vehicle control device includes a control unit that outputs a result of calculation based on input information, The control unit acquiring a physical quantity related to the speed of the vehicle; acquiring a physical quantity related to a required braking force required to decelerate the vehicle; When the vehicle is decelerated based on a physical quantity related to the required braking force, a control command is output to cause the drive device to generate a driving force while the friction braking force is being generated. (2) In a more preferred embodiment, in the above embodiment, The control unit When the physical quantity related to the speed falls below a predetermined speed, the control command is output. (3) In another preferred embodiment, in any of the above embodiments, The control unit The control command is output so that the driving force increases as the physical quantity related to the speed and the physical quantity related to the deceleration of the vehicle decrease. (4) In yet another preferred embodiment, in any of the above embodiments, The control unit After it is determined that the vehicle has stopped, the control command is output to maintain the maximum value of the driving force until a predetermined time has elapsed. (5) In yet another preferred embodiment, in any of the above embodiments, The control unit The control command is output so that the driving force is gradually reduced after the maximum value of the driving force is maintained. (6) In yet another preferred embodiment, in any of the above embodiments, The control unit The control command is output so that the sum of the driving force and the force due to the creep phenomenon occurring in the vehicle does not exceed the friction braking force. (7) In yet another preferred embodiment, in any of the above embodiments, The control unit The control command is output so that the driving force decreases as the downward road gradient increases when the vehicle is decelerated. (8) In yet another preferred embodiment, in any of the above embodiments, The control unit The road surface gradient is estimated based on the difference between the differential value of the physical quantity related to the vehicle speed and the sensor value acquired from the acceleration sensor. (9) In yet another preferred embodiment, in any of the above embodiments, The control unit The road surface gradient is estimated based on the difference between the differential value of the physical quantity related to the vehicle speed and the sensor value obtained from the acceleration sensor, and the value obtained and stored from the acceleration sensor when the vehicle is stopped at the road surface gradient. (10) In yet another preferred embodiment, in any of the above embodiments, The drive device is an electric motor. (11) From another viewpoint, a vehicle control method according to the present technical idea includes, in one aspect, A vehicle control method for a vehicle including a friction braking device that generates a friction braking force in the vehicle and a drive device that generates a drive force in the vehicle, the method comprising: acquiring a physical quantity related to the speed of the vehicle; acquiring a physical quantity related to a required braking force required to decelerate the vehicle; When the vehicle is decelerated based on a physical quantity related to the required braking force, a control command is output to cause the drive device to generate a driving force while the friction braking force is being generated. (12) From another viewpoint, a vehicle control system according to the present technical idea, in one aspect thereof, a friction braking device that generates a friction braking force on a vehicle; a drive device that generates a drive force for the vehicle; A control device that outputs a result of calculation based on input information, acquiring a physical quantity related to the speed of the vehicle; acquiring a physical quantity related to a required braking force required to decelerate the vehicle; outputting a control command for causing the drive device to generate a driving force while the friction braking force is being generated when the vehicle is decelerated based on a physical quantity related to the required braking force; a control device; Equipped with. [Explanation of symbols]

[0031] 1 Electric vehicles 2RL, 2RR rear wheel 3 Friction Brake 5. Accelerometer 7 rear motor 11 Wheel speed sensor 13 Rear wheel resolver 17 Vehicle control device 18 Brake control device 20 Rear motor control device 22 Accelerator pedal sensor 23 Brake sensor

Claims

1. outputting a control command to apply a driving force to the vehicle in a state where a friction braking force is acting on the vehicle immediately before the vehicle is stopped; Vehicle control device.

2. A vehicle control method executed by a vehicle control device mounted on a vehicle, comprising: outputting a control command to apply a driving force to the vehicle in a state where a friction braking force is acting on the vehicle immediately before the vehicle is stopped; Vehicle control method.

3. a friction braking device that generates a friction braking force on a vehicle; a drive device that generates a drive force for the vehicle; a control device that outputs a control command to apply the driving force to the vehicle while the friction braking force is acting on the vehicle immediately before the vehicle is stopped; A vehicle control system comprising:

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