Vehicle control device, vehicle control method, and vehicle control system

Abstract

When the vehicle is decelerated on the basis of the total braking torque, when a control command for generating a driving force on the basis of the driving device is output in a state in which the friction braking force is generated, the vehicle speed at which the control command is involved is changed on the basis of the total braking torque.

Description

Technical Field

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

[0002] Patent document 1 discloses the following technology: with the goal of suppressing pitching changes when a vehicle is about to stop, a physical quantity related to the vehicle speed and a physical quantity related to the required braking force required to decelerate the vehicle are obtained, and when the vehicle is decelerated based on the physical quantity related to the required braking force, a driving force is generated by a driving device while a friction braking force is generated.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-056583 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, in the above-mentioned conventional vehicle control device, the driving force increases as the vehicle speed decreases, but the speed at which the driving force starts to be generated is always a constant value regardless of the magnitude of the required braking force, so there is a concern that smooth parking cannot be achieved effectively.

[0008] One of the objects of the present invention is to provide a vehicle control device, a vehicle control method, and a vehicle control system that can realize smooth parking.

[0009] Means for solving problems

[0010] A vehicle control device in one embodiment of the present invention, when decelerating a vehicle based on a physical quantity related to a total braking force, while generating a friction braking force, when outputting a control instruction for generating a driving force based on a driving device, changes a physical quantity related to the speed of the vehicle causing the control instruction to intervene based on the physical quantity related to the total braking force.

[0011] According to one embodiment of the present invention, smooth parking can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of an electric vehicle 1 including the vehicle control system according to the first embodiment.

[0013] Figure 2 This is a control block diagram of the rear motor 7 according to the first embodiment.

[0014] Figure 3 This is a control block diagram of the total braking torque calculation unit 34 according to the first embodiment.

[0015] Figure 4 This is a control block diagram of the control gain calculation unit 35 according to the first embodiment.

[0016] Figure 5 This is a control block diagram of the addition torque calculation unit 37 according to the first embodiment.

[0017] Figure 6 1 is a diagram showing the gain characteristics of the speed-based control gain map 53 in the first embodiment.

[0018] Figure 7 1 is a diagram showing the gain characteristics of the speed-based control gain map 53 according to the first embodiment with respect to the vehicle speed.

[0019] Figure 8 It is a time chart of the vehicle speed, the rear motor torque, and the front-rear acceleration of the vehicle in the comparative example.

[0020] Fig. 9 It is a time chart of the vehicle speed, the rear motor torque, and the front-rear acceleration of the vehicle in the anti-jerk control according to the first embodiment.

[0021] Fig.10 1 is a diagram showing gain characteristics of the speed-based control gain map 53 in the second embodiment.

[0022] Fig.11 1 is a diagram showing gain characteristics of the speed-based control gain map 53 in the third embodiment.

[0023] Fig.12 1 is a diagram showing gain characteristics of the speed-based control gain map 53 according to the third embodiment with respect to the vehicle speed.

[0024] Fig.13 This is a control block diagram of the friction brake 3 according to the fourth embodiment.

[0025] Fig.14 This is a control block diagram of the total braking torque calculation unit 73 according to the fourth embodiment.

[0026] Fig.15 This is a control block diagram of the subtraction braking force calculation unit 74 according to the fourth embodiment.

[0027] Fig.16 It is a time chart of the vehicle speed, the braking torque, and the front-rear acceleration of the vehicle when no disturbance occurs in the anti-jerk control according to the fourth embodiment.

[0028] Fig.17 This is a time chart of the vehicle speed, the braking torque, and the longitudinal acceleration of the vehicle when a disturbance occurs during the anti-jerk control according to the fourth embodiment. DETAILED DESCRIPTION

[0029] [Implementation method 1]

[0030] Figure 1 This is a schematic diagram of an electric vehicle 1 including the vehicle control system according to the first embodiment.

[0031] The electric vehicle 1 has front wheels 2FL, 2FR, rear wheels 2RL, 2RR, and friction brakes (brakes) (friction brake devices) 3FL, 3FR, 3RL, 3RR, which are provided on each wheel and generate friction braking force on the wheel (hereinafter, the friction brakes of each wheel are also collectively referred to as friction brakes 3).

[0032] The electric vehicle 1 has a rear motor (drive device) 7 that outputs torque to the 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 speed reducer 8, a differential 10, and rear axles 6RL and 6RR.

[0033] Each wheel 2FL, 2FR, 2RL, 2RR has a wheel speed sensor 11FR, 11FL, 11RL, 11RR for detecting the wheel speed. The rear motor 7 has a rear wheel resolver 13 for detecting the motor speed. In addition, the electric vehicle 1 has a G sensor 5 for detecting the acceleration of the vehicle in the front-rear direction (hereinafter, also referred to as acceleration).

[0034] The friction brake 3 presses the brake pad along the rotation axis direction of each wheel relative to the brake rotor that rotates integrally with each wheel, and generates braking force by friction. The friction brake 3 of the first embodiment presses the brake pad by a wheel cylinder that works by brake fluid pressure, but it can also be set as a structure that presses the brake pad via a ball screw mechanism driven by an electric motor, etc., without special limitation.

[0035] The electric vehicle 1 includes 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 electric power boosted by a DC-DC converter 16 .

[0036] The electric vehicle 1 includes a vehicle control device (control unit) 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.

[0037] The vehicle control device 17 obtains information from various sensors such as the rear wheel rotary transformer 13, the accelerator pedal sensor 22 for detecting the accelerator operation amount, the brake sensor 23 for detecting the brake operation amount, and the gear position sensor 24, and performs comprehensive control of the vehicle. The vehicle control device 17 distributes the torque output according to the driver's accelerator operation, brake operation, etc., and outputs the driver's required torque to be output by the rear motor 7 according to the required torque.

[0038] The brake control device 18 obtains information from various sensors such as the brake sensor 23, sets a torque conversion value of the target braking force of the vehicle, namely a target brake torque, generates brake hydraulic pressure required for each wheel according to the target brake torque, and outputs it to the friction brake 3 through the hydraulic piping 18a.

[0039] The battery control device 19 monitors the charge and discharge state of the high voltage battery 15 and the single battery cells constituting the high voltage battery 15. The battery control device 19 calculates the battery required torque limit value based on the charge and discharge state of the high voltage battery 15, etc. The battery required torque limit value is the maximum torque allowed in the rear motor 7. For example, when the charge amount of the high voltage battery 15 decreases, the battery required torque limit value is set to a value smaller than usual.

[0040] The rear motor control device 20 controls the electric power supplied to the rear motor 7 based on the rear required torque.

[0041] In the electric vehicle 1 of the first embodiment, in order to suppress the uncomfortable shaking of the vehicle when parking and reduce the fatigue of the passengers, anti-jerk control is implemented in which the rear motor 7 outputs a driving torque equivalent to the total braking torque estimated from the braking torque actually generated in the vehicle when parking. As a result, the front and rear jerk (acceleration) generated when parking at a certain brake operation amount can be reduced by about 68% compared with the case without anti-jerk control. That is, even without skillful brake operation, smooth parking can be achieved.

[0042] Figure 2 This is a control block diagram of the rear motor 7 according to the first embodiment.

[0043] The driver requested torque calculation unit 31 calculates the driver requested torque based on the accelerator operation amount and the vehicle speed.

[0044] The slope resistance calculation unit 32 calculates the resistance acting on the vehicle due to the road surface slope, i.e., the slope resistance, based on the vehicle speed, the G sensor value, and the vehicle weight. Specifically, the estimated slope acceleration due to the slope is obtained from the deviation between the differential value of the vehicle speed and the G sensor value, and the slope resistance is calculated from the estimated slope acceleration due to the slope and the vehicle weight.

[0045] The estimated friction braking force correction gain calculation unit 33 calculates a final correction gain for correcting the estimated error of the estimated friction braking force accompanying the change of the block μ (friction coefficient) based on the G sensor value, vehicle speed, estimated friction braking force, running resistance, vehicle weight, motor torque, and brake pad temperature. If the block μ changes due to temperature change, humidity change, etc., the estimated friction force will deviate from the braking force actually generated on the vehicle due to braking. Therefore, the block μ is estimated, and in order to eliminate the error of the estimated block μ relative to the nominal value of the block μ, a gain for correcting the estimated friction braking force (torque conversion value) is calculated.

[0046] The estimated friction braking force is obtained as the sum of the estimated friction braking forces of the wheels. The estimated friction braking force Bi of each wheel is calculated using the following formula (1).

[0047] Estimated friction braking force of each wheel Bi = brake fluid pressure × hydraulic cylinder area × brake effective radius × block μ (nominal value)… (1)

[0048] Here, once the nominal value of the block μ is set, it will not be changed during driving. The temperature-μ characteristic of the brake pad is acquired in advance as a map, and the nominal value is set with reference to the map. The temperature of the brake pad when calculating the nominal value can be the outside air temperature at the start of driving, or a predetermined temperature (e.g., 20°C) can be used.

[0049] The running resistance may be calculated based on changes in the running resistance with respect to changes in the vehicle weight and the vehicle speed, or may be estimated.

[0050] The estimated friction braking force may be estimated based on the amount of stroke of the driver's brake pedal instead of the brake fluid pressure.

[0051] The total braking torque calculation section 34 calculates the total braking torque based on the running resistance, the estimated friction braking force, the gradient resistance, and the final correction gain. Figure 3This is a control block diagram of the total braking torque calculation unit 34 of the first embodiment. The braking force torque conversion unit 41 converts the estimated friction braking force into the estimated friction braking torque. The multiplier 42 multiplies the estimated friction braking torque by the final correction gain to calculate the corrected estimated friction braking torque that corrects the estimated error associated with the change in μ of the brake pad. The first adder 43 and the second adder 44 add the torque equivalent to the slope resistance and the torque equivalent to the running resistance to the corrected estimated friction braking torque. The limiter 45 compares the value obtained by adding the torque equivalent to the slope resistance and the torque equivalent to the running resistance to the corrected estimated friction braking torque with 0, and outputs the larger value as the total braking torque.

[0052] The control gain calculation section 35 calculates a control gain based on the vehicle speed and the total braking torque. Figure 4 This is a control block diagram of the control gain calculation unit 35 of the first embodiment. The acceleration estimation value calculation unit 51 calculates the acceleration by differentiating the vehicle speed. The acceleration-based control gain map 52 sets the acceleration-based control gain corresponding to the acceleration. In the acceleration-based control gain map 52, in the case of a deceleration whose absolute value is smaller than the predetermined value x2(G), the acceleration-based control gain is set to 1 (100%). On the other hand, in the case of a deceleration whose absolute value is greater than the predetermined value x2(G), the acceleration-based control gain is gradually reduced as the absolute value of the deceleration increases. The minimum value of the acceleration-based control gain is set to 0 (0%). In this way, it is possible to avoid adding torque during emergency braking. In addition, during emergency braking, it is of course preferable to ensure the braking force rather than suppress vibration in the pitch direction.

[0053] The speed-based control gain map (gain characteristic map) 53 sets a speed-based control gain (control gain) corresponding to the vehicle speed (physical quantity related to the speed of the vehicle) and the total braking torque (physical quantity related to the total braking force). The details of the speed-based control gain map 53 will be described later. The parking determination unit 54 calculates the time until the vehicle stops for each control cycle based on the current vehicle speed and the total braking torque, and clears the parking determination flag (=0) when the time until the vehicle stops is other than 0, and sets the parking determination flag (=1) when the time until the vehicle stops is 0. The control gain rate limiting unit 55 limits the change speed of the increase side and the decrease side of the speed-based control gain. In addition, when the parking determination flag (=1) is set, the change speed limit value of the decrease side used previously is changed. In addition, the timing of clearing and setting the parking determination flag may not be the timing when the time until the vehicle stops becomes 0, but may be set below a prescribed value and cleared above a prescribed value.

[0054] The multiplier 56 outputs the value obtained by multiplying the control gain based on acceleration by the control gain based on speed as the final control gain. The multiplier 36 multiplies the total braking torque by the control gain to calculate the total braking torque after multiplication by the control gain. The addition torque calculation unit 37 calculates the addition torque as the anti-jerk control torque based on the driver's required torque and the total braking torque after multiplication by the control gain. Figure 5 1 is a control block diagram of the addition torque calculation unit 37 of the first embodiment. The limiter 61 compares the driver's required torque with 0 and outputs the larger value. The comparator 62 subtracts the output of the limiter 61 from the total braking torque multiplied by the control gain. The limiter 63 compares the output of the comparator 62 with 0 and outputs the larger value as the addition torque.

[0055] The adder 38 adds the addition torque to the driver requested torque, and obtains the added torque as the post-requested torque.

[0056] Next, the speed-based control gain map 53 according to the first embodiment will be described in detail.

[0057] Figure 6 The gain characteristics of the speed-based control gain map 53 in the first embodiment are shown.

[0058] The speed-based control gain map 53 is a three-dimensional map that takes the vehicle speed and the total braking torque as input and outputs the speed-based control gain. The speed-based control gain has the following characteristics: it decreases linearly as the total braking torque decreases only in a specified area near the total braking torque of 0, and reaches a maximum value of 1 in most areas beyond the specified area. In addition, the maximum value can also be set to a positive value other than 1. In addition, the speed-based control gain is set to increase linearly as the vehicle speed decreases. And, as shown in Figure 7 As shown in FIG. 1 , the speed-based control gain is set so that as the total braking torque increases, the vehicle speed at which the value rises from 0 (the speed at which the gain increase starts) increases. That is, the speed-based control gain has the following characteristics: as the total braking torque increases, the vehicle speed at which the anti-jerk control command intervenes (the vehicle speed at which the generation of the driving force based on the anti-jerk control starts) increases.

[0059] In the first embodiment, Figure 7In the example, when the total braking torque is |X1|>|X2|>|X3|, the gain increase start speed is Y1>Y2>Y3. Furthermore, when |X1| is 3 times |X3| and |X2| is 2 times |X3|, the gain increase start speed is Y1>Y2>Y3. Furthermore, when |X1| is 3 times |X3| and |X2| is 2 times |X3|, the gain increase start speed is Y1>Y3 and Y2 is 2 times Y3. That is, the speed-based control gain has the following characteristics: as the braking torque increases, the vehicle speed at which the anti-jerk control command intervenes increases linearly. As a result, regardless of the magnitude of the total braking force, the same deceleration feeling can be achieved while the vehicle speed is reduced under any total braking torque, and as a result, the discomfort caused to the driver can be reduced. For example, consider the total braking torque corresponding to X1 being -0.3 [G], X2 being -0.2 [G], and X3 being -0.1 [G], and Y1 being 3 [km / h], Y2 being 2 [km / h], and Y3 being 1 [km / h]. In the first embodiment, the speed-based control gain is set to increase linearly with respect to the decrease in vehicle speed in each total braking torque, but it may be set to have a characteristic in which the value increases slowly when the vehicle speed is high and increases more as the vehicle speed decreases.

[0060] Next, the effects of the first embodiment will be described.

[0061] Figure 8 This is a timing diagram of the vehicle speed, rear motor torque, and acceleration in the front-rear direction of the vehicle when the vehicle speed at which the generation of the driving force is started is constant, which is a comparative example of implementation mode 1. The control gain in the anti-jerk control is set only according to the vehicle speed, regardless of the size of the total braking torque. In this comparative example, if the vehicle speed is always Y1 [km / h], the control gain is increased according to the decrease in the vehicle speed. When the total braking torque is X1 [Nm], the increase in torque based on the anti-jerk control starts at time t2, and the vehicle stops at time t4. On the other hand, when the total braking torque is X2 (Nm) (<X1), the increase in torque based on the anti-jerk control starts at time t1, and the vehicle stops at time t3. Therefore, in the comparative example, the acceleration characteristics of the vehicle until the vehicle stops are different for each total braking torque. That is, the deceleration feeling is different for each total braking torque, so there is a concern that the driver will feel uncomfortable. Specifically, if the deceleration disappears prematurely despite a relatively small total braking torque, or if the torque increases from a low speed despite a relatively large total braking torque, the driver may feel uncomfortable.

[0062] In contrast, the vehicle control device 17 of the first embodiment changes the vehicle speed at which the anti-jerk control command intervenes based on the total braking torque. Specifically, as the total braking torque increases, the vehicle speed at which the anti-jerk control command intervenes increases. When the total braking torque is X1 [Nm], the increase in torque based on the anti-jerk control begins at time t1, and the vehicle stops at time t3. When the total braking torque is X2 [Nm], the increase in torque based on the anti-jerk control begins at time t2, and the vehicle stops at time t3. That is, in the vehicle control device 17 of the first embodiment, the acceleration characteristics of the vehicle until the vehicle stops can be approximated to the characteristics of a preset target regardless of the total braking torque. As a result, smooth parking can be achieved without causing discomfort to the driver regardless of the required braking force.

[0063] At this time, as the total braking torque increases, the vehicle braking device 17 linearly increases the vehicle speed at which the anti-jerk control command intervenes. Fig. 9 As shown in the timing diagram of , the changes in acceleration in each total braking torque are consistent, and the smooth parking as the target can be achieved. That is, in the anti-jerk control of embodiment 1, a constant and good deceleration feeling is always obtained regardless of the total braking force, so the discomfort caused to the driver can be reduced.

[0064] The vehicle control device 17 outputs the speed-based control gain based on the speed-based control gain map 53, which is a pre-prepared three-dimensional map that takes the total braking torque and the vehicle speed as input and takes the speed-based control gain as output, and changes the anti-jerk control command according to the speed-based control gain. Thus, the optimal speed-based control gain for achieving the desired acceleration characteristics according to the total braking torque and the vehicle speed can be obtained.

[0065] In the speed-based control gain map 53 , the speed-based control gain increases linearly as the vehicle speed decreases. This allows efficient generation of driving force immediately before the vehicle stops, in addition to during rapid deceleration.

[0066] [Implementation method 2]

[0067] The basic structure of the second embodiment is the same as that of the first embodiment, and therefore only the parts different from the first embodiment will be described.

[0068] Fig.10: is a diagram showing the gain characteristics of the speed-based control gain map 53 in Implementation Example 2. For the speed-based control gain, in each total braking torque, the change gradient of the speed-based control gain relative to the vehicle speed is set to two stages. Specifically, in the area where the vehicle speed is close to 0, it is set so that the rate of change of the speed-based control gain relative to the vehicle speed change is lower than in other areas. It is set so that the greater the total braking torque, the greater the vehicle speed at which the rate of change of the speed-based control gain is switched. In addition, it can also be set so that the increase gradient of the speed-based control gain gradually decreases as the vehicle speed decreases. As a result, it is easy to return the pitch angle of the vehicle caused by braking before the vehicle stops to 0, so the impact during parking can be further suppressed.

[0069] [Implementation method 3]

[0070] The basic structure of the third embodiment is the same as that of the first embodiment, and therefore only the parts different from the first embodiment will be described.

[0071] Fig.11 : This is a diagram showing the gain characteristics of the speed-based control gain map 53 in Embodiment 2. The speed-based control gain is set so that the rate of change of the speed-based control gain with respect to the vehicle speed change is lower than that in other regions only in the region where the total braking torque is greater than the predetermined value X0, in the region where the vehicle speed is close to 0. In the region where the total braking torque is less than the predetermined value X0, the speed-based control gain with respect to the vehicle speed changes linearly. Fig.12 1 is a diagram showing the gain characteristics of the speed-based control gain map 53 relative to the vehicle speed in Embodiment 3, showing the case where |X1|>|X2|>|X0|>|X3|. In addition, it is also possible to set the increase gradient of the speed-based control gain to gradually decrease as the vehicle speed decreases in the region where the total braking torque is greater than the predetermined value T1.

[0072] When the total braking torque is relatively large, the pitch angle generated by the braking force also becomes large, so by quickly increasing the control gain based on the speed, the effect of applying high torque for a long time to make the pitch angle 0 is large. On the other hand, when the total braking torque is small, the pitch angle generated by the braking force is small, so it is assumed that the time taken to make the pitch angle 0 is also short, so the gain characteristic can also be set to linear.

[0073] [Implementation method 4]

[0074] The basic structure of the fourth embodiment is the same as that of the first embodiment, and therefore only the parts different from the first embodiment will be described.

[0075] In the vehicle control system of the fourth embodiment, the anti-jerk control is implemented to reduce the friction braking force from the reference friction braking force (reference friction braking force) in order to suppress the uncomfortable shaking of the vehicle when parking and reduce the fatigue of the occupants. Here, the reference friction braking force is an estimated friction braking force estimated based on the stroke of the brake pedal.

[0076] Fig.13 This is a control block diagram of the friction brake 3 according to the fourth embodiment.

[0077] The disturbance estimation unit 71 estimates disturbance based on the slope resistance, the driver's required torque, the G sensor value, the running resistance, and the vehicle weight. The disturbance is basically estimated using the following equation (2) when the brake is not applied.

[0078] Disturbance = G sensor value × vehicle weight - braking force equivalent to driver's required torque - slope resistance - driving resistance... (2)

[0079] Furthermore, a configuration may be adopted in which estimation is performed even when the influence of the block μ change is small, such as when the estimated friction braking force is extremely small.

[0080] The estimated friction braking force correction gain calculation unit 72 calculates a final correction gain for correcting an estimated error in the estimated friction braking force associated with a change in the pad μ (friction coefficient) based on the disturbance, the G sensor value, the running resistance, the vehicle speed, the estimated friction braking force, the vehicle weight, the motor torque, and the brake pad temperature. The calculation method of the final correction gain is the same as that of the estimated friction braking force correction gain calculation unit 33 of the first embodiment, but in the estimated friction braking force correction gain calculation unit 72, an estimated friction braking force correction gain for correcting an error associated with the disturbance is further calculated.

[0081] The total braking torque calculation section 73 calculates the total braking torque based on the estimated friction braking force, the running resistance, the gradient resistance, the disturbance, and the final correction gain. Fig.14 This is a control block diagram of the total braking torque calculation unit 73 according to Embodiment 4. The third adder 81 adds the torque corresponding to the disturbance to the value obtained by adding the torque corresponding to the gradient resistance and the torque corresponding to the running resistance to the corrected estimated friction braking torque.

[0082] The subtraction braking force calculation unit 74 calculates the subtraction braking force based on the estimated friction braking force, the disturbance, the driver's required torque, and the final correction gain. Fig.15This is a control block diagram of the subtraction braking force calculation unit 74 of implementation mode 4. The comparator 91 subtracts the slope resistance from the braking force corresponding to the driver's required torque, and calculates the braking force corresponding to the driver's required torque taking into account the slope resistance. The absolute value of the output of the comparator 91 is calculated in the absolute value calculation unit 92. The multiplier 93 divides the output of the absolute value calculation unit 92 by the final correction gain, and calculates the absolute value of the braking force corresponding to the driver's required torque after correction. The comparator 94 subtracts the absolute value of the braking force corresponding to the corrected driver's required torque from the estimated friction braking force. The limiter 95 compares the value obtained by subtracting the absolute value of the braking force corresponding to the corrected driver's required torque from the estimated friction braking force with 0, and outputs the larger value as the subtraction braking force.

[0083] The multiplier 75 multiplies the subtraction braking force by the control gain to calculate the subtraction braking force multiplied by the control gain. The comparator 76 subtracts the subtraction braking force multiplied by the control gain from the estimated friction braking force to calculate the post-subtraction friction braking force. The brake control device 18 uses the post-subtraction friction braking torque, which is the torque conversion value of the post-subtraction friction braking force, as the target braking torque.

[0084] Next, the effects of the fourth embodiment will be described.

[0085] Fig.16 It is a time chart of the vehicle speed, the braking torque, and the front-rear acceleration of the vehicle when no disturbance occurs in the anti-jerk control according to the fourth embodiment.

[0086] In the fourth embodiment, the vehicle speed at which the anti-jerk control command intervenes is also increased linearly as the total braking torque increases. When the total braking torque is X1 [Nm], the reduction of the braking torque based on the anti-jerk control is started at time t1, and the vehicle stops at time t3. When the total braking torque is X2 [Nm], the reduction of the braking torque based on the anti-jerk control is started at time t2, and the vehicle stops at time t3. Thus, as in the first embodiment, a constant and good deceleration feeling can be obtained regardless of the total braking force, and the discomfort caused to the driver can be reduced.

[0087] Fig.17 This is a time chart of the vehicle speed, the braking torque, and the longitudinal acceleration of the vehicle when a disturbance occurs during the anti-jerk control according to the fourth embodiment.

[0088] In the control gain calculation unit 35, the speed-based control gain calculated based on the total braking torque is set so that the gain increase start speed becomes larger as the total braking torque becomes larger. Here, in the fourth embodiment, in the total braking torque calculation unit 73, the total braking torque is calculated in consideration of the disturbance. Therefore, the gain increase start speed of the speed-based control gain varies according to the magnitude of the disturbance. When the total braking torque is X1 [Nm], the reduction of the braking torque based on the anti-jerk control starts at time t1', and the vehicle stops at time t3. When the total braking torque is X2 [Nm], the reduction of the braking torque based on the anti-jerk control starts at time t2', and the vehicle stops at time t3. In this way, in the fourth embodiment, by calculating the total braking torque in consideration of the disturbance, the anti-jerk control can be intervened from a more suitable gain increase start speed, so that the ride comfort can be improved regardless of the disturbance.

[0089] [Other implementation methods]

[0090] Although the embodiments for implementing the present invention have been described above, the specific configuration of the present invention is not limited to the configuration of the embodiments, and design changes and the like that do not depart from the gist of the invention are also included in the present invention.

[0091] In the embodiment, the estimated friction braking force is set as input, but the braking force and the braking torque are values ​​that can be converted from vehicle parameters such as the effective radius of the tire, so the estimated friction braking torque can also be input. In this case, the effective radius of the tire can also be estimated instead of a specified value.

[0092] In embodiments 1-3, the output is output as a driving torque, but similarly to the relationship between the braking force and the braking torque, it can be a driving force that can be converted by the tire effective radius, or it can be a longitudinal acceleration or longitudinal jerk converted using vehicle parameters such as vehicle weight.

[0093] Furthermore, in the fourth embodiment, the output is set as braking force, but since it is a value that can be converted using vehicle parameters such as the effective radius of the tire, the output may be estimated friction braking torque or longitudinal acceleration or longitudinal jerk converted using vehicle parameters such as vehicle weight.

[0094] In the embodiment, an example of applying the present invention to a rear-wheel drive electric vehicle is shown, but it may also be a front-wheel drive electric vehicle or a four-wheel drive electric vehicle. In addition, it is not limited to electric vehicles, and it may also be a vehicle having an engine as an internal combustion engine, or a hybrid vehicle that can use both an engine and a motor to travel. That is, as long as a structure that can apply torque from the drive source side or a structure that can reduce friction braking is used when the vehicle stops using the friction brake, within the range where the vehicle can stop or the range where the braking force acts between the drive wheel and the road surface.

[0095] The vehicle weight may be detected by a sensor such as a suspension height sensor, or may be estimated.

[0096] In the first to fourth embodiments, the speed-based control gain mapping may also be configured to prepare a plurality of speed-based control gain mappings according to the vehicle weight and select an appropriate mapping structure. In addition, in the first to fourth embodiments, the speed-based control gain mapping makes the gain 1 when the speed is 0 even when the total braking torque is large, but may also be configured to be a mapping in which the maximum value of the gain decreases as the total braking torque increases when the total braking torque is greater than a predetermined value.

[0097] As for the brake pad temperature, the brake pad temperature can be obtained through a sensor, and the brake pad temperature change at each moment can also be estimated.

[0098] In Embodiment 4, the disturbance may be estimated by detecting the roughness of the road surface from a stereo camera, etc. In addition, a structure may be provided in which the road surface state is detected by a stereo camera, etc., and when the disturbance increases due to the road surface, the braking force is reduced earlier than when the original braking torque is intervened.

[0099] In addition, the present invention is not limited to the above-mentioned embodiments, and includes various modified examples. For example, the above-mentioned embodiments are embodiments described in detail in order to easily explain the present invention, and are not necessarily limited to having all the structures described. In addition, a part of the structure of a certain embodiment can be replaced with the structure of other embodiments, and in addition, the structure of other embodiments can be added to the structure of a certain embodiment. In addition, with respect to a part of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0100] This application claims priority based on Japanese Patent Application No. 2022-138912 filed on September 1, 2022. The entire disclosure of Japanese Patent Application No. 2022-138912 filed on September 1, 2022 including specification, claims, drawings, and abstract is incorporated herein by reference in its entirety.

[0101] Description of Reference Numerals

[0102] 1 ... electric vehicle (vehicle), 3 ... friction brake (friction brake device), 7 ... rear motor (drive device), 17 ... vehicle control device (control unit).

Claims

1. A vehicle control device, which is a vehicle control device provided for a vehicle having a friction braking device for generating a friction braking force on the vehicle and a driving device for generating a driving force on the vehicle, wherein: The vehicle control device includes a control unit that outputs a result calculated 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 total braking force used to decelerate the vehicle; as well as When the vehicle is decelerated based on the physical quantity related to the total braking force, while the friction braking force is generated, when a control command for generating a driving force by the driving device is output, The physical quantity related to the speed of the vehicle causing the control command to intervene is changed based on the physical quantity related to the total braking force.

2. The vehicle control device according to claim 1, wherein: The control unit increases the physical quantity related to the speed of the vehicle at which the control command intervenes as the physical quantity related to the total braking force increases.

3. The vehicle control device according to claim 2, wherein: The control unit linearly increases the physical quantity related to the speed of the vehicle at which the control command intervenes as the physical quantity related to the total braking force increases.

4. The vehicle control device according to claim 1, wherein: The control unit: outputting a control gain based on a pre-prepared gain characteristic map, wherein the gain characteristic map takes a physical quantity related to the total braking force and a physical quantity related to the speed of the vehicle as inputs and takes a gain as output; and The control command is changed based on the control gain.

5. The vehicle control device according to claim 4, wherein: The gain characteristic map is a three-dimensional map that takes a physical quantity related to the total braking force and a physical quantity related to the speed of the vehicle as inputs and takes a gain as output.

6. The vehicle control device according to claim 4, wherein: The control gain is set to linearly increase as the physical quantity related to the speed of the vehicle decreases.

7. The vehicle control device according to claim 4, wherein: The control gain is set so that the increase gradient of the control gain gradually decreases as the physical quantity related to the speed of the vehicle decreases.

8. The vehicle control device according to claim 4, wherein: The control gain is set such that, when the physical quantity related to the total braking force is greater than a predetermined value, as the physical quantity related to the speed of the vehicle becomes smaller, the increase gradient of the control gain gradually becomes smaller, The control gain is set so as to linearly increase as the physical quantity related to the speed of the vehicle decreases when the physical quantity related to the total braking force is equal to the prescribed value or is smaller than the prescribed value.

9. The vehicle control device according to claim 4, wherein: The control gain is set so that the increase gradient of the control gain gradually increases as the physical quantity related to the speed of the vehicle decreases.

10. A vehicle control device, the vehicle control device being provided for a vehicle having a friction braking device for generating a friction braking force on the vehicle and a driving device for generating a driving force on the vehicle, wherein: The vehicle control device includes a control unit that outputs a result calculated 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 total braking force used to decelerate the vehicle; Acquiring a physical quantity related to a disturbance affecting the behavior of the vehicle; as well as When the vehicle is decelerated based on a physical quantity related to the total braking force, When a control command for increasing the driving force by the driving device or reducing the friction braking force from the reference friction braking force by the friction braking device is output, The physical quantity related to the speed of the vehicle causing the control command to intervene is changed based on the magnitude of the physical quantity related to the total braking force and the physical quantity related to the disturbance.

11. A vehicle control method, the method being executed by a control unit mounted on a vehicle having a friction brake device for generating a friction brake force on the vehicle and a drive device for generating a drive force on the vehicle, wherein: Through the control unit: Acquiring a physical quantity related to the speed of the vehicle; acquiring a physical quantity related to a total braking force used to decelerate the vehicle; as well as When the vehicle is decelerated based on the physical quantity related to the total braking force, while the friction braking force is generated, when a control command for generating a driving force by the driving device is output, The physical quantity related to the speed of the vehicle causing the control command to intervene is changed based on the physical quantity related to the total braking force.

12. A vehicle control system comprising: The friction brake device generates friction braking force on the vehicle; a driving device for causing the vehicle to generate driving force; and The control device outputs the result calculated based on the input information, The control device: Acquiring a physical quantity related to the speed of the vehicle; acquiring a physical quantity related to a total braking force used to decelerate the vehicle; as well as When the vehicle is decelerated based on the physical quantity related to the total braking force, while the friction braking force is generated, when a control command for generating a driving force by the driving device is output, The physical quantity related to the speed of the vehicle causing the control command to intervene is changed based on the physical quantity related to the total braking force.

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