Vehicle control device

Abstract

To suppress a deceleration feeling of a vehicle which can be perceived by otolith of a driver in the vehicle from decreasing, when braking operation of the vehicle is just started.SOLUTION: A vehicle control device 50 comprises: a determining part M13 that determines whether an execution condition including a condition that braking operation of a vehicle 10 is just started is satisfied or not; and a braking force correcting part M15 that when it is determined that the execution condition is satisfied, increases and corrects braking force that is applied to the vehicle 10, on the basis of a correction amount corresponding to occupant acceleration force that is force in a running direction of the vehicle 10 that is applied to an occupant in the vehicle 10 accompanying application of the braking force to the vehicle 10.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a vehicle control device.

Background Art

[0002] As one of the sensations that a vehicle driver feels comfortable driving the vehicle, there is a sense of being the main body of movement. The sense of being the main body of movement is a sense in which the predicted result of vehicle movement by the driver and the result of vehicle movement perceived by the driver match. The driver's vision and otoliths function as sensors for the driver to perceive the result of vehicle movement. And it is known that the driver's vision and otoliths are likely to perceive the deceleration of the vehicle at the initial stage of braking. At the initial stage of braking, minimizing the deviation between the timing at which vision feels the deceleration of the vehicle and the timing at which the otoliths feel the deceleration of the vehicle leads to an improvement in the sense of being the main body of movement during vehicle braking.

[0003] Patent Document 1 discloses a control device that varies the front-to-rear braking force distribution, which is the distribution of the front-wheel braking force applied to the front wheels and the rear-wheel braking force applied to the rear wheels, according to the required deceleration of the vehicle. When the required deceleration is included in the first region, the control device adjusts the front-to-rear braking force distribution so that the distribution of the front-wheel braking force becomes larger compared to the case where the required deceleration is included in the second deceleration. The first region is a region with a smaller deceleration than the second region. Thereby, the control device can increase the pitch angle and pitch angular velocity of the vehicle at the initial stage of braking. By increasing the pitch angle and pitch angular velocity of the vehicle at the initial stage of braking in this way, the driver's vision can easily perceive the deceleration of the vehicle.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the vehicle decelerates, a deceleration inertial force, which is an inertial force acting forward of the vehicle due to the deceleration, acts on the driver. When the deceleration inertial force acts on the otoliths of the driver, the otoliths perceive the deceleration of the vehicle.

[0006] However, when the pitch angle or pitch angular velocity of the vehicle increases, a pitching inertial force, which is an inertial force caused by the pitching motion of the vehicle, acts on the driver's head. The magnitude of the pitching inertial force increases as the pitch angular velocity increases. The pitching inertial force includes a component above the vehicle and a component behind the vehicle. The component of the pitching inertial force behind the vehicle cancels out the deceleration inertial force. Therefore, if the pitch angular velocity of the vehicle is large at the initial stage of braking, the deceleration feeling of the vehicle perceived by the otoliths of the driver decreases. When the deceleration feeling of the vehicle perceived by the otoliths decreases, the timing at which the otoliths perceive the deceleration of the vehicle tends to be delayed.

Means for Solving the Problems

[0007] The vehicle control device for solving the above problems includes a determination unit that determines whether an execution condition including that it is the initial stage of braking of the vehicle is satisfied, and when it is determined that the execution condition is satisfied, a braking force correction unit that increases and corrects the braking force applied to the vehicle by a correction amount corresponding to the occupant acceleration force, which is the force in the traveling direction of the vehicle applied to the occupant of the vehicle as the braking force is applied to the vehicle.

Effects of the Invention

[0008] The above vehicle control device has an effect that it can suppress a decrease in the deceleration feeling of the vehicle perceived by the otoliths of the driver of the vehicle at the initial stage of braking.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, an embodiment of the vehicle control device will be described with reference to FIGS. 1 to 12. <Overall Configuration of Vehicle> FIG. 1 illustrates a vehicle 10 to which a vehicle control device 50 is applied. The vehicle 10 includes front wheels 11 and rear wheels 12 as wheels. Inside the vehicle body 13 of the vehicle 10, a seat on which the occupants of the vehicle 10 sit is provided. In FIG. 1, a seat 15 for a driver 100, which is an example of an occupant, is illustrated. The seat 15 is configured such that the height position of the seat portion 16 can be automatically varied by the operation of an actuator 17. The “height position” referred to here is the position with respect to the seat floor 19 on which the seat 15 is installed. Therefore, when the seat portion 16 moves upward of the vehicle, the seat portion 16 is positioned at a high position.

[0011] As shown in FIG. 2, the vehicle 10 includes a drive device 20 and a brake device 30. The drive device 20 includes, for example, a first motor generator 21 which is a motor generator for the front wheels 11, and a second motor generator 22 which is a motor generator for the rear wheels 12. By functioning the motor generators 21 and 22 as electric motors, a driving force is transmitted from the motor generators 21 and 22 to the wheels 11 and 12. On the other hand, by functioning the motor generators 21 and 22 as generators, a regenerative braking force corresponding to the power generation amount of the motor generators 21 and 22 is applied to the wheels 11 and 12. The regenerative braking force applied to the front wheels 11 is referred to as “front-wheel regenerative braking force BPFre”. The regenerative braking force applied to the rear wheels 12 is referred to as “rear-wheel regenerative braking force BPRre”.

[0012] The brake device 30 includes a plurality of friction brakes 31 provided on the plurality of wheels 11 and 12, and a brake actuator 35. The plurality of friction brakes 31 each have a wheel cylinder 32. The plurality of friction brakes 31 are each configured to be able to generate a frictional braking force corresponding to the hydraulic pressure of the wheel cylinder 32 on the wheels. The frictional braking force applied to the front wheels 11 is referred to as “front-wheel frictional braking force BPFf”. The frictional braking force applied to the rear wheels 12 is referred to as “rear-wheel frictional braking force BPRf”.

[0013] The brake actuator 35 adjusts the supply and discharge of brake fluid to the plurality of wheel cylinders 32 according to the mode of the driver's braking operation. The "braking operation" means that the driver operates the brake pedal 37. For example, the brake actuator 35 has a hydraulic pressure generating source such as an electric pump or an electric cylinder. The brake actuator 35 is configured to be able to individually adjust the hydraulic pressure of the wheel cylinder 32 for the front wheels 11 and the hydraulic pressure of the wheel cylinder 32 for the rear wheels 12.

[0014] <Vehicle detection system> The detection system of the vehicle 10 includes a plurality of sensors that output detection signals corresponding to the detection results to the vehicle control device 50. The plurality of sensors include, for example, a wheel speed sensor 41, an acceleration sensor 42, and a brake sensor 43. The wheel speed sensor 41 is provided for each wheel. The plurality of wheel speed sensors 41 respectively detect the rotational speed of the corresponding wheel. The acceleration sensor 42 detects the longitudinal acceleration of the vehicle 10. The brake sensor 43 detects, for example, the operation amount of the brake pedal 37 by the driver. Note that, as the brake sensor, a sensor that detects the operating force of the brake pedal 37 by the driver may be adopted.

[0015] The rotational speed of the wheel based on the detection signal of the wheel speed sensor 41 is referred to as "wheel speed VW". The acceleration of the vehicle 10 based on the detection signal of the acceleration sensor 42 is referred to as "longitudinal acceleration GX". The operation amount based on the detection signal of the brake sensor 43 is referred to as "braking operation amount OA".

[0016] <Vehicle control device> The vehicle control device 50 includes a seat control device 60, a drive control device 70, and a brake control device 80. These plurality of control devices 60, 70, 80 are respectively configured so that various types of information can be transmitted and received via an in-vehicle network.

[0017] <Seat control device> The seat control device 60 operates the actuator 17 of the seat 15. The seat control device 60 has a processing circuit 61. An example of the processing circuit 61 is an electronic control unit. In this case, the processing circuit 61 has a CPU and a memory that stores a control program executed by the CPU.

[0018] When the CPU executes the control program in the memory, the processing circuit 61 functions as an occupant posture adjustment unit M41 that adjusts the height position of the seat part 16 of the seat 15 through the control of the actuator 17. The occupant posture adjustment unit M41 can adjust the posture of the driver 100 such that the height position of the head 101 of the driver 100 sitting on the seat 15 becomes lower by adjusting the height position of the seat part 16.

[0019] <Drive control device> The drive control device 70 operates the drive device 20. The drive control device 70 has a processing circuit 71. An example of the processing circuit 71 is an electronic control unit. In this case, the processing circuit 71 has a CPU and a memory that stores a control program executed by the CPU.

[0020] When the CPU executes the control program in the memory, the processing circuit 71 functions as a drive control unit M31 and a regeneration control unit M33. The drive control unit M31 controls the driving force Fd of the vehicle 10 by causing the motor generators 21, 22 to function as electric motors. The regeneration control unit M33 controls the front-wheel regeneration braking force BPFre and the rear-wheel regeneration braking force BPRre by causing the motor generators 21, 22 to function as generators.

[0021] <Brake control device> The braking control device 80 has a processing circuit 81. An example of the processing circuit 81 is an electronic control device. In this case, the processing circuit 81 has a CPU 82, a first memory 83, and a second memory 84. The first memory 83 stores a control program executed by the CPU 82. The second memory 84 stores the calculation results of the CPU 82 and the like. By the CPU 82 executing the control program in the first memory 83, the processing circuit 81 controls the braking actuator 35. Further, the processing circuit 81 transmits a command value related to regenerative braking to the drive control device 70.

[0022] <Behavior of the vehicle during braking> As shown in FIG. 3, when the vehicle 10 is braked, a vehicle deceleration inertial force Fpm, which is an inertial force accompanying deceleration, acts on the vehicle body 13. As a result, a pitching motion occurs in which the front part of the vehicle is displaced downward while the rear part of the vehicle is displaced upward. On the other hand, when the vehicle is braked, a pitching motion suppressing force Canti, which is a force for suppressing such a pitching motion, acts on the vehicle body 13. Therefore, the larger the difference between the magnitude of the vehicle deceleration inertial force Fpm and the magnitude of the pitching motion suppressing force Canti, the larger the pitching motion of the vehicle 10 becomes. That is, the pitch angle θ of the vehicle 10 becomes larger. In other words, by adjusting the magnitude of the pitching motion suppressing force Canti, the pitching motion during vehicle braking can be controlled to some extent.

[0023] The magnitude of the pitching motion suppressing force Canti can be changed by changing the distribution of the braking force. The "distribution of the braking force" as referred to here includes the following distributions. · The ratio α that the front wheel braking force BPF occupies in the vehicle braking force BP.

[0024] · The ratio β that the front wheel frictional braking force BPFf occupies in the front wheel braking force BPF. · The ratio γ that the rear wheel frictional braking force BPRf occupies in the rear wheel braking force BPR. The vehicle braking force BP is the sum of the front-wheel braking force BPF and the rear-wheel braking force BPR. The front-wheel braking force BPF is the sum of the front-wheel frictional braking force BPFf and the front-wheel regenerative braking force BPFre. The rear-wheel braking force BPR is the sum of the rear-wheel frictional braking force BPRf and the rear-wheel regenerative braking force BPRre.

[0025] By applying a braking force to the front wheels 11, an anti-dive force FAD acts on the front part of the vehicle. By applying a braking force to the rear wheels 12, an anti-lift force FAL acts on the rear part of the vehicle. The anti-dive force FAD is a force that suppresses the displacement of the front part of the vehicle downward below the vehicle. The anti-lift force FAL is a force that suppresses the displacement of the rear part of the vehicle upward above the vehicle. That is, the anti-dive force FAD and the anti-lift force FAL act in a direction that suppresses the pitching motion of the vehicle 10. Therefore, the sum of the anti-dive force FAD and the anti-lift force FAL corresponds to the pitching motion suppression force Canti.

[0026] In the suspensions for the front wheels 11 and the rear wheels 12 provided in the vehicle 10, the suspension geometry is set such that the anti-lift force FAL is greater than the anti-dive force FAD when the front-wheel braking force BPF and the rear-wheel braking force BPR are equal to each other. Therefore, by reducing the ratio α of the front-wheel braking force BPF in the vehicle braking force BP, the magnitude of the pitching motion suppression force Canti increases.

[0027] The frictional braking force acts at the contact point between the wheel and the road surface 200. On the other hand, the regenerative braking force acts at the center of the axle of the wheel. For this reason, by increasing the ratio β of the front-wheel frictional braking force BPFf in the front-wheel braking force BPF, the anti-dive force FAD and thus the magnitude of the pitching motion suppression force Canti increase. By increasing the ratio γ of the rear-wheel frictional braking force BPRf in the rear-wheel braking force BPR, the anti-lift force FAL and thus the magnitude of the pitching motion suppression force Canti increase.

[0028] The pitching motion suppression force Canti can be expressed, for example, by the following relational expression (D1). In the relational expression (D1), "Lf" is the horizontal distance from the vehicle center of gravity GC to the axle 11a of the front wheel 11. "Lr" is the horizontal distance from the vehicle center of gravity GC to the axle 12a of the rear wheel 12. "θFf" is the angle formed by the straight line connecting the contact point P1 between the front wheel 11 and the road surface 200 and the rotation center Cf of the suspension for the front wheel 11, and the straight line extending in the horizontal direction on the road surface 200. "θRf" is the angle formed by the straight line connecting the contact point P2 between the rear wheel 12 and the road surface 200 and the rotation center Cr of the suspension for the rear wheel 12, and the straight line extending in the horizontal direction on the road surface 200. "θFre" is the angle formed by the straight line connecting the center of the axle 11a of the front wheel 11 and the rotation center Cf of the suspension for the front wheel 11, and the straight line extending in the horizontal direction on the road surface 200. "θRre" is the angle formed by the straight line connecting the center of the axle 12a of the rear wheel 12 and the rotation center Cr of the suspension for the rear wheel 12, and the straight line extending in the horizontal direction on the road surface 200.

[0029] [Number] [Regarding the sense of the moving body during vehicle braking] Referring to FIGS. 4 to 10, the visual perception of deceleration and the otolith perception of deceleration at the initial stage of braking of the vehicle 10 will be described.

[0030] The dashed line in FIG. 6 is an example of the transition of the pitch angular velocity dθ of the vehicle 10 when the braking force distribution is the first distribution. The solid line in FIG. 6 is an example of the transition of the pitch angular velocity dθ when the braking force distribution is the second distribution. The second distribution is a distribution that can reduce the magnitude of the pitching motion suppression force Canti compared to the case of the first distribution. Therefore, in the case of the second distribution, the pitch angular acceleration dDθ, which is the acceleration rate of the pitch angular velocity dθ at the initial stage of braking, becomes larger compared to the case of the first distribution.

[0031] The driver 100 of the vehicle 10 can perceive the deceleration of the vehicle 10 through both vision and otoliths. At the initial stage of braking of the vehicle 10, the vehicle 10 performs a pitching motion in a direction that increases the pitch angle θ of the vehicle 10. When the pitch angle θ changes, the direction of the driver 100's line of sight changes downward. By changing the direction of the line of sight in this way, the driver 100 perceives the deceleration visually. Therefore, the greater the change in the pitch angle θ at the initial stage of braking, the earlier the driver 100 can perceive the deceleration visually.

[0032] FIG. 7 shows the relationship between the visual deceleration perception time TMv, which is the time from the start of braking of the vehicle 10 until the driver 100 visually perceives the deceleration, and the jerk dGX of the vehicle 10. The jerk dGX is the value obtained by differentiating the longitudinal acceleration GX with respect to time. The dashed line in FIG. 7 shows the relationship between the deceleration perception time TMv and the jerk dGX when the distribution of the braking force is the first distribution. The solid line in FIG. 7 shows the relationship between the deceleration perception time TMv and the jerk dGX when the distribution of the braking force is the second distribution. As is clear from the figure, the greater the jerk dGX, which has a certain correlation with the pitch angular velocity dθ, the shorter the deceleration perception time TMv. Also, when the jerk dGX is the same, the deceleration perception time TMv in the case of the second distribution is shorter than the deceleration perception time TMv in the case of the first distribution. That is, the more the distribution of the braking force can reduce the magnitude of the pitching motion suppression force Canti, the earlier the driver 100's vision can perceive the deceleration.

[0033] The otoliths are located in the driver 100's head 101. Therefore, when the inertial force acting on the head 101 increases, the driver's otoliths perceive the deceleration. As shown in FIGS. 4 and 5, during vehicle braking, a deceleration inertial force FIx, which is an inertial force accompanying the deceleration of the vehicle 10, acts on the head 101. The direction in which the deceleration inertial force FIx acts on the head 101 is in the vehicle forward direction. The magnitude of the deceleration inertial force FIx increases as the longitudinal acceleration GX increases.

[0034] Also, at the initial stage of braking, as described above, since the vehicle 10 pitches, the head 101 of the driver 100 sitting on the seat 15 also pitches. At this time, as shown in FIG. 5, a pitching inertial force FIθ, which is an inertial force in the direction of shifting the line of sight upward, acts on the head 101 of the driver 100. The pitching inertial force FIθ increases as the pitching angular velocity dθ increases. The pitching inertial force FIθ includes a rearward inertial force component FIθx, which is an inertial force component behind the vehicle, and an upward braking force component FIθz, which is a braking force component above the vehicle. The direction of the rearward inertial force component FIθx is behind the vehicle and is opposite to the direction of the deceleration inertial force FIx.

[0035] When the inertial force acting in the longitudinal direction of the vehicle 10 on the head 101 of the driver 100 during vehicle braking is defined as the braking inertial force FI, the difference between the magnitude of the deceleration inertial force FIx and the magnitude of the rearward inertial force component FIθx of the pitching inertial force FIθ becomes the braking inertial force FI. Therefore, the greater the magnitude of the deceleration inertial force FIx, the greater the braking inertial force FI. Also, the smaller the magnitude of the rearward inertial force component FIθx of the pitching inertial force FIθ, the greater the braking inertial force FI. In other words, the greater the magnitude of the rearward inertial force component FIθx, the smaller the braking inertial force FI.

[0036] FIG. 8 shows the relationship between the otolith deceleration perception time TMo, which is the time from the start of braking of the vehicle 10 until the otoliths of the driver 100 perceive deceleration, and the jerk dGX of the vehicle 10. The dashed line in FIG. 8 shows the relationship between the otolith deceleration perception time TMo and the jerk dGX when the braking force distribution is the above-mentioned first distribution. The solid line in FIG. 8 shows the relationship between the otolith deceleration perception time TMo and the jerk dGX when the braking force distribution is the above-mentioned second distribution. As is also clear from the figure, the greater the jerk dGX, which has a certain correlation with the pitching angular velocity dθ, the shorter the deceleration perception time TMo. Also, when the jerk dGX is the same, the deceleration perception time TMv in the case of the second distribution is longer than the deceleration perception time TMv in the case of the first distribution. That is, the more the braking force distribution can reduce the magnitude of the pitching motion suppression force Canti, the more delayed the perception of deceleration by the driver's otoliths.

[0037] Therefore, the greater the pitching motion of the vehicle 10 at the initial stage of braking to accelerate the driver 100's visual perception of deceleration, the later the driver 100's otolith perception of deceleration will be. Conversely, if the pitching motion of the vehicle 10 at the initial stage of braking is reduced to accelerate the otolith perception of deceleration, the visual perception of deceleration will be delayed.

[0038] FIG. 9 shows the transition of the longitudinal acceleration GX. In FIG. 9, the first deceleration pattern PT1 is indicated by a dashed line, while the second deceleration pattern PT2 is indicated by a solid line. The second deceleration pattern PT2 is a deceleration pattern in which the deceleration of the vehicle 10 at the initial stage of braking is greater than that of the first deceleration pattern PT1.

[0039] FIG. 10 shows the relationship between the deceleration perception time TMo and the jerk dGX when the magnitude of the rear inertial force component FIθx of the pitching inertial force FIθ does not change due to the difference in the deceleration pattern. The dashed line in FIG. 10 shows the relationship between the deceleration perception time TMo and the jerk dGX when the vehicle 10 is decelerated according to the first deceleration pattern PT1. The solid line in FIG. 10 shows the relationship between the deceleration perception time TMo and the jerk dGX when the vehicle 10 is decelerated according to the second deceleration pattern PT2. As is also clear from these figures, by decelerating the vehicle 10 according to the second deceleration pattern PT2, the otoliths of the driver 100 can perceive deceleration earlier. This is because the magnitude of the braking inertial force FI increases as the magnitude of the deceleration inertial force FIx can be increased.

[0040] When the vehicle decelerates, the magnitude of the pitching inertial force FIθ acting on the head 101 of the driver 100 increases as the linear distance Rθ from the pitch rotation center PC, which is the center of the pitching motion of the vehicle 10, to the head 101 becomes longer. By lowering the height position of the head 101, such a linear distance Rθ becomes shorter. When the head 101 is displaced downward by changing the posture of the seat 15, the magnitude of the pitching inertial force FIθ and thus the braking inertial force FI becomes smaller. For example, as shown in FIG. 4, by displacing the seat portion 16 of the seat 15 downward, the height Z from the seat floor 19 to the head 101 can be lowered. For example, the pitching inertial force FIθ can be expressed by the following relational expression (D2). In the relational expression (D2), "Mh" is the mass of the head 101 of the driver 100.

[0041] [Number] <Functional Configuration of the Processing Circuit of the Braking Control Device> Referring to FIG. 2, the functional configuration of the processing circuit 81 of the braking control device 80 will be described.

[0042] When the CPU 82 executes the control program of the first memory 83, the processing circuit 81 functions as a plurality of functional units. The plurality of functional units include, for example, a required braking force derivation unit M11, a determination unit M13, a braking force correction unit M15, a distribution adjustment unit M17, and a braking control unit M19.

[0043] <Required Braking Force Derivation Unit> When a braking request occurs in the vehicle 10, the required braking force derivation unit M11 derives a vehicle braking force required value BPRq, which is the required value of the vehicle braking force BP. When the driver 100 is performing a braking operation, the required braking force derivation unit M11 derives the vehicle braking force required value BPRq such that the value increases as the braking operation amount OA increases. Note that when deceleration of the vehicle 10 is requested from another control device other than the braking control device 80, the required braking force derivation unit M11 may derive a value corresponding to the request as the vehicle braking force required value BPRq.

[0044] <Determination Unit> The determination unit M13 determines whether the execution conditions including that it is the initial stage of braking of the vehicle 10 are satisfied. Here, the "initial stage of braking" refers to the period from the time when a braking request occurs until a predetermined time has elapsed. The predetermined time is set according to the specifications of the vehicle 10.

[0045] The execution conditions may include other conditions in addition to being the initial stage of braking. For example, the execution conditions may include that the driver is performing a braking operation. In this case, the determination unit M13 determines that the execution conditions are satisfied when both being the initial stage of braking and the driver performing a braking operation are satisfied. On the other hand, the determination unit M13 determines that the execution conditions are not satisfied when at least one of being the initial stage of braking and the driver performing a braking operation is not satisfied.

[0046] <Braking force correction unit> When it is determined that the execution conditions are satisfied, the braking force correction unit M15 increases and corrects the vehicle braking force required value BPRq by a correction amount corresponding to the occupant acceleration force applied to the driver 100 of the vehicle 10 as the braking force is applied to the vehicle 10. The occupant acceleration force is the force applied to the head 101 of the driver 100 in the traveling direction of the vehicle 10. When the vehicle 10 travels forward of the vehicle, the front of the vehicle corresponds to the "traveling direction of the vehicle 10".

[0047] When the vehicle brakes, the above-mentioned pitching inertial force FIθ is applied to the head 101 of the driver 100. And the pitching inertial force FIθ includes a rear inertial force component FIθx applied to the head 101 in the opposite direction (rearward) of the traveling direction of the vehicle 10.

[0048] The pitching inertial force FIθ can be expressed by the above relational expression (D2). The head translational acceleration dDHx, which is the acceleration of the head 101 of the driver 100 at this time, can be expressed by the following relational expression (D3). From the relational expressions (D2) and (D3), the head translational acceleration dDHx can also be expressed as in the following relational expression (D4). Note that the pitch angular acceleration dDθ becomes the acceleration corresponding to the "occupant acceleration force".

[0049] [Number] When the braking force that can cancel the head-on acceleration dDHx is defined as the braking force correction amount ΔBP, the braking force correction amount ΔBP can be expressed by the following relational expression (D5). In the relational expression (D5), "M" is the mass of the vehicle 10. Further, based on the relational expressions (D4) and (D5), the braking force correction amount ΔBP can also be expressed by the following relational expression (D6).

[0050] [Number] As described above, the pitch angular acceleration dDθ is the acceleration corresponding to the "occupant acceleration force". For example, in the relational expression (D6), "M·dDθ" corresponds to the occupant acceleration force. Therefore, this braking force correction amount ΔBP corresponds to the correction amount corresponding to the above-mentioned occupant acceleration force. Further, the above relational expression (D2) refers to the linear distance Rθ from the above pitch rotation center PC to the head 101. The linear distance Rθ is information regarding the driver 100 (occupant). Therefore, it can be said that the braking force correction unit M15 estimates the occupant acceleration force (that is, the product of the mass M of the vehicle 10 and the pitch angular acceleration) based on the vehicle braking force BP and the information regarding the driver 100. Also, it can be said that the braking force correction unit M15 can derive the braking force correction amount ΔBP based on the occupant acceleration force (that is, the product of the mass M of the vehicle 10 and the pitch angular acceleration).

[0051] The braking force correction unit M15 derives the vehicle braking force target value BPTr as the sum of the vehicle braking force required value BPRq and the braking force correction amount ΔBP. Thereby, the braking force correction unit M15 can increase and correct the vehicle braking force BP.

[0052] [Distribution adjustment unit] When the vehicle braking force BP is increased and corrected by the braking force correction amount ΔBP, the distribution adjustment unit M17 adjusts the distribution of the vehicle braking force target value BPTr so as to suppress an increase in the pitching motion of the vehicle 10 caused by the increase in the braking force by the amount of the braking force correction amount ΔBP.

[0053] The translational acceleration increase amount ΔdDHx of the head generated by the braking force correction amount ΔBP is defined as such. At this time, the translational acceleration increase amount ΔdDHx can be expressed by the following relational expression (D7).

[0054]

Equation

[0055]

Equation

[0056]

Equation

[0057]

Equation

[0058] <Braking control unit> The braking control unit M19 controls the vehicle braking force BP by operating the brake actuator 35. For example, when it is determined that the above execution conditions are satisfied, the braking control unit M19 operates the brake actuator 35 based on the command values of the front-wheel frictional braking force BPFf and the rear-wheel frictional braking force BPRf derived by the distribution adjustment unit M17. Also, the braking control unit M19 transmits the command values of the front-wheel regenerative braking force BPFre and the rear-wheel regenerative braking force BPRre derived by the distribution adjustment unit M17 to the drive control device 70.

[0059] When the regenerative control unit M33 of the drive control device 70 acquires the command values of the front-wheel regenerative braking force BPFre and the rear-wheel regenerative braking force BPRre, it controls the plurality of motor generators 21, 22 based on the command values.

[0060] <Braking control process> With reference to FIGS. 11 and 12, a braking control process, which is a series of processes executed by the processing circuit 81 of the braking control device 80 when decelerating the vehicle 10 by applying braking force, will be described. The processing circuit 81 repeatedly executes the braking control process at every predetermined control cycle.

[0061] As shown in FIG. 11, in step S11, the processing circuit 81 determines whether a braking operation is being performed. If the processing circuit 81 determines that a braking operation is being performed (S11: YES), the process proceeds to step S13. On the other hand, if the processing circuit 81 determines that a braking operation is not being performed (S11: NO), the braking control process is temporarily terminated.

[0062] In step S13, the processing circuit 81 derives a vehicle braking force required value BPRq based on the braking operation amount OA. In the subsequent step S15, the processing circuit 81 determines whether it is the initial stage of braking. For example, if the elapsed time from the time when the braking request occurred exceeds a predetermined time indicating the length of the initial braking time, it is regarded as not being the initial stage of braking. If the elapsed time is less than or equal to the predetermined time, it is regarded as being the initial stage of braking. When the processing circuit 81 determines that it is the initial stage of braking (S15: YES), the process proceeds to step S17. On the other hand, when the processing circuit 81 determines that it is not the initial stage of braking (S15: NO), the process proceeds to step S41. That is, when the processing circuit 81 determines that the execution condition is satisfied, the process proceeds to step S17, while when it determines that the execution condition is not satisfied, the process proceeds to step S41.

[0063] In step S17, the processing circuit 81 derives a pitch angular acceleration required value dDθR, which is the required value of the pitch angular acceleration dDθ. Referring to FIG. 12, an example of the derivation process of the pitch angular acceleration required value dDθR will be described. FIG. 12 shows an example of a map for deriving the pitch angular acceleration required value dDθR.

[0064] In the initial stage of braking, it can be inferred that the pitch angular acceleration dDθ changes in a quadratic function. Specifically, the pitch angular acceleration dDθ increases toward the peak value. After the pitch angular acceleration dDθ reaches the peak value, the pitch angular acceleration dDθ decreases toward 0 (zero). And the greater the increasing speed of the braking operation amount OA, the easier it is for the peak value of the pitch angular acceleration dDθ to become larger.

[0065] FIG. 12 shows a plurality of maps corresponding to the acceleration rate of the braking operation amount OA. The processing circuit 81 selects, for example, a map corresponding to the acceleration rate of the braking operation amount OA at the start of braking from among the plurality of maps. The processing circuit 81 reads out a pitch angular acceleration corresponding to the elapsed time from the start of braking from the selected map, and derives the pitch angular acceleration as a pitch angular acceleration required value dDθR.

[0066] Returning to FIG. 11, when the processing circuit 81 derives the pitch angular acceleration required value dDθR, the process proceeds to step S19. In step S19, the processing circuit 81 derives a head translational acceleration required value dDHxR, which is a required value of the head translational acceleration dDHx. For example, the processing circuit 81 derives the head translational acceleration required value dDHxR using the above relational expression (D4). At this time, the processing circuit 81 substitutes the pitch angular acceleration required value dDθR derived in step S17 into "dDθ" in the above relational expression (D4). The processing circuit 81 substitutes an estimated value of the height position of the head 101 based on the height position of the seat part 16 into the height Z from the seat floor 19 to the head 101. Of course, when the height position of the head 101 can be measured by an in-vehicle camera or the like, the processing circuit 81 may substitute the measured value into the height Z.

[0067] In the subsequent step S21, the processing circuit 81 derives a braking force correction amount ΔBP. For example, the processing circuit 81 derives the braking force correction amount ΔBP using the above relational expression (D5). At this time, the processing circuit 81 substitutes the head translational acceleration required value dDHxR derived in step S19 into "dDHx" in the relational expression (D5).

[0068] In the next step S23, the processing circuit 81 derives various parameters for suppressing an increase in the pitch angle θ of the vehicle 10 due to increasing the vehicle braking force required value BPRq by the braking force correction amount ΔBP.

[0069] For example, the processing circuit 81 adjusts the plurality of ratios α, β, γ so as to obtain a pitching motion suppression force Canti that can satisfy the above relational expression (D10). Also, for example, the processing circuit 81 derives the height Z for satisfying the above relational expression (D10) as the seat height command value ZTr. Then, the processing circuit 81 proceeds to step S25 with the processing.

[0070] In step S25, the processing circuit 81 derives a command value for the braking force based on the vehicle braking force target value BPTr, which is the sum of the vehicle braking force required value BPRq and the braking force correction amount ΔBP, and the plurality of ratios α, β, γ derived in step S23. For example, the processing circuit 81 derives a command value for the front-wheel frictional braking force BPFf, a command value for the front-wheel regenerative braking force BPFre, a command value for the rear-wheel frictional braking force BPRf, and a command value for the rear-wheel regenerative braking force BPRre as the command value for the braking force.

[0071] In the next step S27, the processing circuit 81 executes braking control based on the command value derived in step S25. The processing circuit 81 operates the brake actuator 35 so that the front-wheel frictional braking force BPFf becomes its command value and the rear-wheel frictional braking force BPRf becomes its command value. The processing circuit 81 transmits the command values for the front-wheel regenerative braking force BPFre and the rear-wheel regenerative braking force BPRre to the drive control device 70.

[0072] When the processing circuit 71 of the drive control device 70 receives the command values for the front-wheel regenerative braking force BPFre and the rear-wheel regenerative braking force BPRre, it controls the power generation amount of the first motor generator 21 so that the front-wheel regenerative braking force BPFre becomes its command value. Also, the processing circuit 71 controls the power generation amount of the second motor generator 22 so that the rear-wheel regenerative braking force BPRre becomes its command value.

[0073] When the processing circuit 81 of the brake control device 80 executes the braking control, it proceeds to step S29 with the processing. In step S29, the processing circuit 81 transmits the seat height command value ZTr derived in step S23 to the seat control device 60.

[0074] When the processing circuit 61 of the seat control device 60 receives the seat height command value ZTr, it operates the actuator 17 so that the height Z becomes the seat height command value ZTr. Thereafter, the processing circuit 81 of the braking control device 80 temporarily ends the braking control process.

[0075] In step S41, the processing circuit 81 decreases the braking force correction amount ΔBP toward 0 (zero). For example, the processing circuit 81 derives the larger of the value obtained by subtracting a predetermined value from the braking force correction amount ΔBP and 0 (zero) as the latest value of the braking force correction amount ΔBP.

[0076] In the subsequent step S43, the processing circuit 81 derives a braking force command value based on the vehicle braking force target value BPTr, which is the sum of the vehicle braking force request value BPRq and the braking force correction amount ΔBP, and the plurality of ratios α, β, γ. At this time, the processing circuit 81 may hold the plurality of ratios α, β, γ at the values when the process of step S23 was last executed, or may reset the plurality of ratios α, β, γ to their initial values. The processing circuit 81 derives a command value for the front-wheel frictional braking force BPFf, a command value for the front-wheel regenerative braking force BPFre, a command value for the rear-wheel frictional braking force BPRf, and a command value for the rear-wheel regenerative braking force BPRre as the braking force command values.

[0077] In the next step S45, the processing circuit 81 executes braking control based on the command value derived in step S43. The processing circuit 81 operates the braking actuator 35 so that the front-wheel frictional braking force BPFf becomes its command value and the rear-wheel frictional braking force BPRf becomes its command value. The processing circuit 81 transmits the command values of the front-wheel regenerative braking force BPFre and the rear-wheel regenerative braking force BPRre to the drive control device 70.

[0078] When the processing circuit 71 of the drive control device 70 receives the command values of the front-wheel regenerative braking force BPFre and the rear-wheel regenerative braking force BPRre, it controls the power generation amount of the first motor generator 21 so that the front-wheel regenerative braking force BPFre becomes its command value. Also, the processing circuit 71 controls the power generation amount of the second motor generator 22 so that the rear-wheel regenerative braking force BPRre becomes its command value.

[0079] When the processing circuit 81 of the braking control device 80 executes braking control, it temporarily terminates the braking control process. In the present embodiment, by functioning as the determination unit M13, the processing circuit 81 executes the processes of steps S11 and S15. By functioning as the required braking force derivation unit M11, the processing circuit 81 executes the process of step S13. By functioning as the braking force correction unit M15, the processing circuit 81 executes the processes of steps S17, S19, and S21. By functioning as the distribution adjustment unit M17, the processing circuit 81 executes the processes of steps S23 and S25. By functioning as the braking control unit M19, the processing circuit 81 executes the process of step S27. Further, when the processing circuit 81 executes the process of step S27, the processing circuit 71 of the drive control device 70 functions as the regeneration control unit M33, and the regenerative braking force of the wheels 11, 12 is adjusted. Further, when the processing circuit 81 executes the process of step S29, the processing circuit 61 of the seat control device 60 functions as the occupant posture adjustment unit M41, and adjusts the posture of the seat 15.

[0080] <Actions and Effects of the Present Embodiment> (1) When the vehicle is braking, the deceleration inertial force FIx associated with the deceleration of the vehicle 10 acts on the head 101 of the driver 100. Also, when the vehicle is braking, the vehicle 10 undergoes a pitching motion. Therefore, the pitching inertial force FIθ, which is an inertial force caused by the pitching motion of the vehicle 10, also acts on the head 101. The deceleration inertial force FIx acts on the head 101 in the vehicle forward direction, whereas the rearward inertial force component FIθx included in the pitching inertial force FIθ acts on the head 101 of the driver 100 in the vehicle rearward direction.

[0081] Here, the greater the braking inertial force FI, which is the difference between the magnitude of the deceleration inertial force FIx and the magnitude of the rearward inertial force component FIθx, the earlier the otoliths of the driver 100 can perceive the deceleration of the vehicle 10.

[0082] However, since pitching motion of the vehicle 10 generates pitching inertial force FIθ (more specifically, rearward inertial force component FIθx) during pitching, perception of deceleration of the vehicle 10 by the otoliths of the driver 100 is delayed.

[0083] In this regard, when the vehicle control device 50 determines that the above execution conditions are satisfied, the vehicle braking force BP is increased and corrected by a braking force correction amount ΔBP corresponding to the pitch angular acceleration dDθ, which is an acceleration corresponding to the occupant acceleration force. By thus increasing and correcting the vehicle braking force BP, even if the pitching inertial force FIθ is applied to the head 101 of the driver 100 during vehicle braking to the extent that the magnitude of the deceleration inertial force FIx can be increased, a decrease in the magnitude of the braking inertial force FI is suppressed. Thereby, the vehicle control device 50 can suppress a delay in perception of deceleration of the vehicle 10 by the otoliths of the driver 100 in the braking process.

[0084] (2) The pitching inertial force FIθ varies not only depending on the vehicle braking force BP but also on the weight of the driver 100 and the like. Therefore, the vehicle control device 50 derives the pitching inertial force FIθ in consideration of information regarding the driver 100. Then, based on the rearward inertial force component FIθx included in such pitching inertial force FIθ, the braking force correction amount ΔBP is derived. Thereby, the vehicle control device 50 can increase and correct the vehicle braking force BP in consideration of the characteristics of the driver 100.

[0085] (3) When the vehicle braking force BP is increased and corrected by the braking force correction amount ΔBP, the deceleration of the vehicle 10 increases, so the magnitude of the pitching inertial force FIθ applied to the head 101 of the driver 100 also increases.

[0086] Therefore, in the vehicle control device 50, the distribution of the braking force, that is, the plurality of ratios α, β, γ are adjusted so that an increase in the pitching motion of the vehicle 10 caused by the increase correction of the vehicle braking force BP is suppressed. As a result, a change in the pitching motion of the vehicle 10 due to an increase in the vehicle braking force BP by the braking force correction amount ΔBP is suppressed. As a result, the vehicle control device 50 can suppress the perception of deceleration of the vehicle 10 by the driver 100's vision from becoming faster due to the increase correction of the vehicle braking force BP. That is, the vehicle control device 50 can reduce the deviation between the timing when the driver 100 can perceive the deceleration of the vehicle 10 by the otoliths and the timing when the driver 100 can perceive the deceleration of the vehicle 10 by the vision.

[0087] (4) In the vehicle control device 50, at the initial stage of braking, the posture of the seat 15 is adjusted so that the height position of the head 101 of the driver 100 becomes lower. By thus lowering the height position of the head 101, the magnitude of the pitching inertial force FIθ becomes smaller. As a result, the vehicle control device 50 can advance the timing at which the otoliths of the driver 100 can perceive the deceleration of the vehicle 10 by an amount that can suppress a decrease in the magnitude of the braking inertial force FI.

[0088] <Modified Example> The above embodiment can be implemented with the following modifications. The above embodiment and the following modified examples can be implemented in combination with each other within a technically non - conflicting range.

[0089] · If the vehicle control device 50 suppresses the pitching motion of the vehicle 10 caused by the increase correction of the vehicle braking force BP by adjusting the distribution of the braking force, it does not have to change the posture of the seat 15 to lower the height position of the head 101 of the driver 100.

[0090] · If the vehicle control device 50 changes the posture of the seat 15 to lower the height position of the head 101 of the driver 100 when increasing the vehicle braking force BP by increase correction, it does not have to change the distribution of the braking force.

[0091] ·When suppressing the pitching motion of the vehicle 10 caused by the increase correction of the vehicle braking force BP, the braking control device 80 may change only some of the plurality of ratios α, β, γ.

[0092] ·If the vehicle to which the vehicle control device 50 is applied is equipped with the first motor generator 21, it may be a vehicle that does not include the second motor generator 22. If the vehicle to which the vehicle control device 50 is applied is equipped with the second motor generator 22, it may be a vehicle that does not include the first motor generator 21. Also, the vehicle to which the vehicle control device 50 is applied may be a vehicle that does not include any of the plurality of motor generators 21, 22.

[0093] ·The braking control device 80 may derive the braking force correction amount ΔBP without considering information regarding the occupant. For example, the braking control device 80 substitutes a preset value for "Z" in the above relational expression (D6).

[0094] ·By increasing the pitch angle θ of the vehicle 10 at the initial stage of braking, the driver 100's visual perception of the deceleration of the vehicle 10 is accelerated. Therefore, when the execution condition is satisfied, the braking control unit M19 may increase the ratio occupied by the front-wheel braking force BPF out of the front-wheel braking force BPF and the rear-wheel braking force BPR. In this case, when it is determined that the execution condition is satisfied, the braking control unit M19 also functions as a "vehicle motion control unit" that causes the vehicle 10 to have a pitching motion. When the braking control unit M19 functions as the vehicle motion control unit in this way, it is preferable that the braking force correction unit M15 derives the braking force correction amount ΔBP in consideration of the acceleration force applied to the driver 100 due to the pitching motion of the vehicle 10 caused by the vehicle motion control unit. In the case of this modification example, the occupant acceleration force is greater than in the case of the above-described embodiment. Therefore, the braking force correction unit M15 derives the braking force correction amount ΔBP so that the value is greater than in the case of the above-described embodiment.

[0095] ·When it is determined that it is the initial stage of braking, the braking control device 80 may determine that the execution condition is satisfied regardless of whether the braking operation is being performed. ·In the above embodiment, the vehicle control device 50 changes the pitching motion mode of the vehicle 10 by changing at least one of the plurality of ratios α, β, and γ. However, the pitching motion mode of the vehicle 10 may be changed by another method. For example, the vehicle control device 50 may change the pitching motion mode of the vehicle 10 by adjusting the elastic force of at least one of the suspension for the front wheels 11 and the suspension for the rear wheels 12.

[0096] ·In the above embodiment, the delay in the driver 100's perception of deceleration due to otoliths is suppressed. However, various processes may be executed to suppress the delay in the perception of deceleration due to otoliths of other passengers other than the driver 100.

[0097] ·The processing circuits 61, 71, and 81 can be configured as a circuit including one or more processors that operate according to a computer program, one or more dedicated hardware circuits such as dedicated hardware that executes at least a part of various processes, or a combination thereof. Examples of the dedicated hardware include, for example, an ASIC (Application Specific Integrated Circuit) which is an integrated circuit for a specific purpose. The processor includes a CPU and memories such as a RAM and a ROM, and the memories store program codes or instructions configured to cause the CPU to execute processes. The memories, that is, the storage media, include any available media that can be accessed by a general-purpose or dedicated computer.

[0098] ·The vehicle to which the vehicle control device 50 is applied may be a vehicle as described below. In the suspension for the front wheels 11 and the suspension for the rear wheels 12, the suspension geometry may be set such that the anti-dive force FAD is greater than the anti-lift force FAL when the front wheel braking force BPF and the rear wheel braking force BPR are of the same magnitude as each other.

[0099] Note that, as used herein, the expression "at least one" means "one or more" of the desired options. As an example, the expression "at least one" as used herein means "only one option" or "both of the two options" if the number of options is two. As another example, the expression "at least one" as used herein means "only one option" or "any combination of two or more options" if the number of options is three or more.

Explanation of Signs

[0100] 10…Vehicle 11, 12…Wheels 15…Seat 17…Actuator 20…Drive device 21, 22…Motor generators 30…Brake device 35…Brake actuator 50…Vehicle control device 60…Seat control device 61…Processing circuit 70…Drive control device 71…Processing circuit 80…Brake control device 81…Processing circuit 100…Driver (an example of an occupant) 101…Head M13…Judgment unit M15…Braking force correction unit M17…Distribution adjustment unit M19…Brake control unit (also functions as a vehicle motion control unit) M33…Regeneration control unit M41…Occupant posture adjustment unit

Claims

1. A determination unit that determines whether an execution condition including being at the initial stage of braking of the vehicle is satisfied, and a braking force correction unit that increases and corrects the braking force applied to the vehicle by a correction amount corresponding to the occupant acceleration force, which is the force in the traveling direction of the vehicle applied to the occupant of the vehicle as the braking force is applied to the vehicle when it is determined that the execution condition is satisfied. A vehicle control device.

2. The braking force correction unit estimates the occupant acceleration force based on the braking force applied to the vehicle and information regarding the occupant, and derives the correction amount based on the occupant acceleration force. The vehicle control device according to Claim 1.

3. When it is determined by the determination unit that the execution condition is satisfied, it includes a vehicle motion control unit that causes the vehicle to perform a pitching motion, and the braking force correction unit derives the correction amount taking into account the acceleration force applied to the occupant along with the pitching motion of the vehicle. The vehicle control device according to Claim 1.

4. A distribution adjustment unit that adjusts the distribution of the braking force generated in the vehicle so as to suppress an increase in the pitching motion of the vehicle caused by an increase in the braking force by the correction amount when the braking force applied to the vehicle is increased and corrected by the correction amount. The vehicle control device according to any one of Claims 1 to 3.

5. When the braking force applied to the vehicle is increased and corrected by the correction amount, it includes an occupant posture adjustment unit that adjusts the posture of the occupant so that the height position of the head of the occupant becomes lower. The vehicle control device according to Claim 1.

Images