Vehicle attitude control device

Abstract

To suppress fluctuations in a fore-and-aft direction of a vehicle while minimizing a pitch behavior generated when the vehicle passes over a convex road surface.SOLUTION: In a vehicle equipped with brake devices 30a to 30d installed on each wheel and capable of applying regenerative braking force to the front and rear wheels through control of front and rear motors 5 and 6, a brake control unit 31 suppresses a vehicle's pitch by applying additional pitch moment through the operation control of the brake devices 30a to 30d and the front and rear motors 5 and 6 based on the vehicle's driving state. When the additional pitch moment is applied multiple times within a predetermined period through operation control of the brake devices 30a to 30d, the change amount in total braking force, which is the sum of braking force from the brake devices 30a to 30d and the regenerative braking force from the front and rear motors 5 and 6, is suppressed to a predetermined value or less during both the individual operation control of the brake devices 30a to 30d and the intervals between operations.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a vehicle attitude control technology using a braking device and a regenerative braking device.

Background Art

[0002] As a technology for stabilizing the attitude of a vehicle when driving on a rough road and improving the comfort of passengers, a method of using a four-wheel active suspension device is known. The reaction force of the suspension device of each wheel is controlled by the four-wheel active suspension device to control the attitude of the vehicle. However, there is a problem that the four-wheel active suspension device is relatively expensive. Therefore, in a vehicle without a four-wheel active suspension device, an attitude control device that controls the attitude by controlling the braking force (brake force) of the four wheels has been proposed.

[0003] For example, in Patent Document 1, an attitude control device that suppresses the pitching behavior of a vehicle by controlling the braking force distribution between the front and rear wheels is disclosed. Further, in Patent Document 2, after the braking force is distributed between the front and rear wheels, in the driving wheels of the front wheels or the rear wheels, the braking force is applied by the frictional braking force and the regenerative braking force. Thereby, since the braking force by not only the friction braking device but also the regenerative braking device is controlled to suppress the pitching behavior, fine control of the braking force is possible.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, for example, when the front and rear wheels cross a convex road surface while the vehicle is running, in order to suppress the pitching behavior generated when the front wheel crosses the convex road surface, the braking force is controlled, and immediately after that, in order to suppress the pitching behavior generated when the rear wheel crosses the convex road surface, the braking force is controlled, so that the braking force acts twice within a relatively short time. Therefore, when the front and rear wheels cross the convex road surface, even if the pitching behavior is suppressed, there is a possibility that the longitudinal acceleration of the vehicle fluctuates greatly, which causes a problem of giving a sense of discomfort to the passengers, especially the driver.

[0006] The present invention has been made in view of such problems, and an object thereof is to provide a vehicle attitude control device that suppresses fluctuations in the longitudinal acceleration of the vehicle while suppressing the pitching behavior generated when the wheels pass over a convex road surface.

Means for Solving the Problems

[0007] To achieve the above object, a vehicle attitude control device according to the present invention is provided in a vehicle in which front, rear, left, and right wheels are suspended by a suspension device, and includes friction braking devices respectively provided on the front, rear, left, and right wheels, a regenerative braking device that applies a regenerative braking force to at least the front and rear wheels among the front, rear, left, and right wheels, a braking control unit that applies a frictional braking force independently to at least the front and rear wheels by controlling the operation of the front, rear, left, and right friction braking devices, and applies a regenerative braking force independently to the front and rear wheels by controlling the operation of the regenerative braking device, a speed detection unit that detects the rotational speeds of the front, rear, left, and right wheels respectively, a longitudinal acceleration detection unit that detects the longitudinal acceleration of the vehicle, a pitch rate detection unit that detects the pitch rate of the vehicle, and the braking control unit executes cooperative control to suppress the pitch behavior of the vehicle by applying an additional pitch moment by controlling the operation of the friction braking device and the regenerative braking device based on the vehicle running state. When the additional pitch moment is applied a plurality of times within a predetermined time by controlling the operation of the friction braking device, during and between the plurality of operations of the friction braking device, the change amount of the total braking force of the braking force by the friction braking device and the braking force by the regenerative braking device is suppressed to a predetermined value or less.

Advantages of the Invention

[0008] When the vehicle attitude control device of the present invention passes over a convex road surface of the vehicle and applies an additional pitch moment a plurality of times within a predetermined time by controlling the operation of the friction braking device, during and between the plurality of operations of the friction braking device, the change amount of the total braking force of the braking force by the friction braking device and the braking force by the regenerative braking device is suppressed to a predetermined value or less. Therefore, it is possible to suppress a change in the longitudinal acceleration of the vehicle and suppress a sense of discomfort of the occupant. Even if the change amount of the total braking force is suppressed to a predetermined value or less, since the frictional braking force and the regenerative braking force can be controlled independently for the front and rear wheels respectively, it is possible to sufficiently obtain a pitch suppression effect.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an attitude control device 10 according to an embodiment of the present invention mounted on a vehicle 1. The attitude control device 10 according to an embodiment of the present invention is mounted on a four-wheel vehicle (hereinafter referred to as vehicle 1) having wheels 3a to 3d (driving wheels) on the front, rear, left, and right of the vehicle body. Between each wheel 3a to 3d of the vehicle 1 and the vehicle body, there is provided a suspension device 11 having an anti-dive and anti-lift geometry, and suspending the wheels 3a to 3d with respect to the vehicle body respectively.

[0011] Each wheel 3a to 3d of the vehicle 1 is provided with a brake device 30a to 30d (friction braking device), respectively. The brake devices 30a to 30d are controlled by a brake control unit 31 (braking control unit), and it is possible to apply arbitrary different braking forces (friction braking forces) to each of the wheels 3a to 3d.

[0012] In the vehicle 1 of the present embodiment, each of the wheels 3a to 3d is driven by an electric motor or an engine. For example, the vehicle 1 is a hybrid vehicle that can drive the front wheels 3a, 3b by a front motor 5 and an engine (not shown), and can drive the rear wheels 3c, 3d by a rear motor 6. In the vehicle 1, regenerative braking is possible in each of the front motor 5 (regenerative braking device) and the rear motor 6 (regenerative braking device). Further, the present invention is applicable to at least a four-wheel drive vehicle in which the four-wheel brake devices 30a to 30d, the front motor 5 that drives the front wheels 3a, 3b, and the rear motor 6 that drives the rear wheels 3c, 3d can be independently controlled, such as a plug-in hybrid vehicle or an electric vehicle that drives the wheels 3a to 3d only by an electric motor.

[0013] The vehicle 1 is provided with a longitudinal acceleration sensor 35 (longitudinal acceleration detection unit) that detects the longitudinal acceleration of the vehicle body, and wheel speed sensors 33a to 33d (speed detection units) that detect the rotational speeds of the respective wheels 3a to 3d, and a pitch rate sensor 36 (pitch rate detection unit) that detects the pitch rate of the vehicle (vehicle body). FIG. 2 is a system configuration diagram of the attitude control device 10.

[0014] The attitude control device 10 includes a longitudinal acceleration sensor 35, wheel speed sensors 33a to 33d of the respective wheels 3a to 3d, a pitch rate sensor 36, a brake control unit 31, an EV-ECU (main control unit 20) that controls the regenerative braking forces of the front motor 5 and the rear motor 6, and the four-wheel brake devices 30a to 30d and the front and rear motors (front motor 5, rear motor 6).

[0015] In this embodiment, the detection values of the longitudinal and lateral acceleration sensors 35 and the wheel speed sensors 33a to 33d are configured to be input to the brake control unit 31. However, for example, a configuration in which the detection values are input via the main control unit 20 that controls the entire vehicle may also be used. The brake control unit 31 and the main control unit 20 are configured to include an input / output device, a storage device (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), a timer, and the like. The brake control unit 31 receives the operation amount of the brake pedal from a brake pedal sensor (not shown), and controls the braking force (brake force) by the brake devices 30a to 30d based on the operation amount of the brake pedal and the like.

[0016] In addition, detection information is input to the brake control unit 31 from the longitudinal and lateral acceleration sensors 35, the wheel speed sensors 33a to 33d, and the pitch rate sensor 36. The attitude control device 10 includes a convex road surface passage determination unit 40 that determines the attitude of the vehicle 1, specifically, that the vehicle 1 is passing over a convex road surface, based on the detection information of the longitudinal and lateral acceleration sensors 35 and the wheel speed sensors 33a to 33d of the respective wheels 3a to 3d, and a pitch suppression control unit 41 that calculates the brake force applied to the respective wheels 3a to 3d so as to reduce the estimated pitch and the regenerative braking force in the front motor 5 and the rear motor 6. The attitude control device 10 estimates the pitch of the vehicle based on the detection information of the longitudinal and lateral acceleration sensors 35, the wheel speed sensors 33a to 33d, and the pitch rate sensor 36, and executes pitch suppression control (coordinated control) to set the brake force applied to the respective wheels 3a to 3d so as to reduce the pitch and the regenerative braking force of the front and rear motors 5 and 6.

[0017] FIG. 3 is an explanatory diagram of the anti-dive force and anti-lift force of the vehicle. FIG. 4 is an explanatory diagram of the anti-nose dive angle, anti-tail lift angle due to the friction brake force of the vehicle, and anti-nose up angle, anti-squat angle due to the regenerative brake force. First, the relationship between the anti-dive force and anti-lift force with respect to the frictional braking force (frictional braking power), the anti-nose-up force with respect to the regenerative braking force (regenerative braking power), the anti-squat force, and the pitch moment in the suspension device of the vehicle 1 will be described.

[0018] As shown in FIGS. 3 and 4, let the distance in the longitudinal direction of the vehicle between the contact points of the front wheels 3a and 3b of the vehicle 1 and the center of gravity A of the vehicle body be a, the distance in the longitudinal direction of the vehicle between the contact points of the rear wheels 3c and 3d of the vehicle 1 and the center of gravity A be b, the height of the center of gravity A from the ground be hCG, the total braking force of the entire vehicle be Fb, the ratio of the frictional braking force on the front wheel 3a, 3b side be λ, the front wheel frictional braking force be Fbf, the rear wheel frictional braking force be Fbr, the front wheel regenerative braking force be Fbif, the rear wheel regenerative braking force be Fbir, the anti-lift angle be βf, the anti-dive angle be βr, the anti-nose-up angle be βfin, and the anti-squat angle be βrin. Then, the pitch moment My, which is the sum of the pitch moment generated by the deceleration of the vehicle 1 and the pitch moment generated by the anti-dive force, anti-lift force, etc. of the suspension device 11, is obtained by the following (Equation 1).

[0019] Fb×hcg - ([Fbf×|tan(βf)| + Fbif×|tan(βfin)|]×a + [Fbr×|tan(βr)| + Fbir×|tan(βrin)|]×b) = My ··· (Equation 1) In (Equation 1), Fbf×|tan(βf)| is the anti-force generated by the front wheel frictional braking force, Fbif×|tan(βfin)| is the anti-force generated by the front wheel regenerative braking force, Fbr×|tan(βr)| is the anti-force generated by the rear wheel frictional braking force, and Fbir×|tan(βrin)| is the anti-force generated by the rear wheel regenerative braking force.

[0020] Also, Fbf + Fbif + Fbr + Fbir = Fb ··· (Equation 2) Fbf≧0, Fbif≧0, Fbr≧0, Fbir≧0 ··· (Equation 3) That is. In addition, in FIG. 4, CR is the instantaneous rotation center during regenerative braking, and CB is the instantaneous rotation center during friction braking.

[0021] The attitude control device 10 executes pitch suppression control to control each braking force so as to cancel this pitch moment My, that is, to approach My = 0. Next, the pitch suppression control executed in the brake control unit 31 in the attitude control device 10 will be described with reference to FIGS. 5 and 6. Note that this pitch suppression control may be executed in the main control unit 20 or other control units.

[0022] FIG. 5 is a control flowchart of the braking amount (braking force Fb). The control shown in FIG. 5 is repeatedly executed every predetermined time (for example, several msec to several tens of msec) when the vehicle 1 is running. First, in step S10, it is determined whether or not the conditions of table A for determining that the vehicle 1 is passing over a convex road surface are satisfied. The conditions of table A are the cases where all of the following conditions 1) to 6) are satisfied. 1) FR wheel acceleration > X_WHEELACC1 2) FL wheel acceleration > X_WHEELACC2 3) |RR wheel speed acceleration| < X_WHEELACC3 4) |RL wheel speed acceleration| < X_WHEELACC4 5) Longitudinal acceleration < X_ACTACC1 6) Pitch rate > X_Pitchrate Condition 1) means that the acceleration of the right front wheel speed input from the right front wheel speed sensor 33b is greater than a predetermined threshold value X_WHEELACC1 set as appropriate.

[0023] Condition 2) is that the acceleration of the left front wheel speed input from the left front wheel speed sensor 33a is greater than a predetermined threshold value X_WHEELACC2 set as appropriate. Condition 3) is that the absolute value of the acceleration of the right rear wheel speed input from the right rear wheel speed sensor 33d is less than a predetermined threshold value X_WHEELACC3 set as appropriate. Condition 4) is that the absolute value of the acceleration of the left rear wheel speed input from the left rear wheel speed sensor 33c is less than a predetermined threshold value X_WHEELACC4 set as appropriate.

[0024] Condition 5) is that the acceleration of the vehicle in the longitudinal direction input from the vehicle longitudinal acceleration sensor is less than the threshold value X_WHEELACC1. Condition 6) is that the pitch rate of the vehicle input from the pitch rate sensor 36 is greater than a predetermined threshold value X_Pitchrate set as appropriate. If all the conditions of Table A are satisfied, proceed to step S20. If at least one of the conditions 1) to 6) of Table A is not satisfied, proceed to step S60.

[0025] When all the conditions 1) to 6) of Table A are established, input the vehicle speed at the time of establishment, and calculate the braking time Time Brake based on the vehicle speed. Time Brake may be calculated using a pre-stored map or the like such that the braking time Time Brake increases as the vehicle speed at the time of establishment of Table A increases. Note that the control of this step in the brake control unit 31 corresponds to the convex road surface passing determination unit 40, and the control of FIGS. 5 and 6 described later corresponds to the pitch suppression control unit 41.

[0026] In step S20, count up the brake timer XTa. Then, proceed to step S30. In step S30, it is determined whether the brake timer XTa is less than the braking time threshold value XTa1 set as appropriate. If the brake timer XTa is less than the braking time threshold value XTa1, the process proceeds to step S40. If the brake timer XTa is greater than or equal to the braking time threshold value XTa1, the process proceeds to step S50.

[0027] In step S40, the braking force Fb is set to the total brake control amount. Then, this routine returns. The total brake control amount is calculated by the following (Equation 4). Total brake = xxF - (1 - (Time Brake - brake Timer) / Time Brake)) × xxF2 ··· (Equation 4) Note that xxF is the parameter initial value of the total braking force set as appropriate, Time brake is the time to apply the brake as described above, and is a value calculated based on the vehicle speed when the condition of Table A is satisfied. Brake Timer is the elapsed time from the start of braking when the condition of Table A is satisfied. xxF2 is a parameter set as appropriate.

[0028] In step S50, the braking force Fb is set to 0. Also, the brake timer XTa is reset to 0. Then, this routine returns. In step S60, it is determined whether the brake timer XTa is 0. If the brake timer XTa is 0, the process proceeds to step S70. If the brake timer XTa is not 0, the process proceeds to step S110.

[0029] In step S70, the brake timer XTa is incremented. Then, the process proceeds to step S80. In step S80, it is determined whether the brake timer XTa is less than the braking time threshold value XTa1. If the brake timer XTa is less than the braking time threshold value XTa1, the process proceeds to step S90. If the brake timer XTa is greater than or equal to the braking time threshold value XTa1, the process proceeds to step S100.

[0030] In step S90, the braking force Fb is set to the braking control amount Total brake calculated by the above (Equation 4). Then, this routine returns. In step S100, the braking force Fb is set to 0. Also, the brake timer XTa is reset to 0. Then, this routine returns. In step S110, the braking force Fb is set to 0. Then, this routine returns.

[0031] Next, the calculation method of the braking force distribution will be described with reference to FIG. 6. FIG. 6 is a flowchart of the calculation of the braking force distribution. The control shown in FIG. 6 is repeatedly executed every predetermined time (for example, several msec to several tens of msec) during the running of the vehicle. First, in step S200, it is determined whether the braking force Fb calculated by the control in FIG. 5 is not 0. If the braking force Fb is not 0, the process proceeds to step S210. If the braking force Fb is 0, the process proceeds to step S240.

[0032] In step S210, it is determined whether the additional pitch moment My is 0. The additional pitch moment My is obtained from the following (Equation 5). My = MAX(pitch rate × GAIN, 0) ··· (Equation 5) Note that pitch rate is the detected value of the pitch rate sensor 36, GAIN is a value set as appropriate, and in (Equation 5), the larger value between the integrated value of pitch rate and GAIN and 0 is set as My.

[0033] If the additional pitch moment My is not 0, the process proceeds to step S220. If the additional pitch moment My is 0, the process proceeds to step S230. In step S220, My (approximate value) is obtained using the above (Equation 1), (Equation 2), and (Equation 3). Then, this routine returns.

[0034] In step S230, an additional pitch moment (My) generated by brake distribution is minimized so as not to affect the pitch behavior of the vehicle. In order to minimize the additional pitch moment My, the braking force distribution ratios of each wheel Fbf, Fbif, Fbr, and Fbir at which the minimum value of My can be achieved may be calculated using Equation 1, Equation 2, and Equation 3. Then, this routine returns.

[0035] In step S240, all of the braking forces Fbf, Fbr, Fbif, and Fbir of each wheel are set to 0. Then, this routine returns. As described above, in the present embodiment, it is determined at any time whether the conditions of Table A are satisfied while the vehicle is running, and when all of the conditions 1) to 6) of Table A are satisfied, it is determined that the vehicle 1 starts passing over the convex road surface. Then, a braking time Time Brake for suppressing pitch is calculated based on the vehicle speed at the start of the passage. Then, until the braking time Time Brake elapses from the determination of the start of passing over the convex road surface, the change amount of the total braking force Total Brake (the total braking force of the friction braking force and the regenerative braking force) of the entire vehicle is set to be constant. The additional pitch moment added to suppress pitch is set based on the detected value of the pitch rate, and based on the additional pitch moment and the total braking force Total Brake of the entire vehicle, the friction braking force Fbf of the front wheels 3a and 3b, the regenerative braking force Fbif of the front wheels 3a and 3b, the friction braking force Fbr of the rear wheels 3c and 3d, and the regenerative braking force Fbir of the rear wheels 3c and 3d are set.

[0036] In this way, within the period of the braking time Time Brake set based on the vehicle speed at the start of passing over the convex road surface, the total braking force Total Brake of the entire vehicle is suppressed to change constantly. Incidentally, when the front wheels 3a and 3b and the rear wheels 3c and 3d of the vehicle 1 pass over a convex road surface, pitch behavior in which the pitch angular velocity peaks with a time difference occurs multiple times within a relatively short period. Further, even when one of the front wheels and the rear wheels passes over a convex road surface, since the pitch angular velocity fluctuates periodically, pitch behavior in which the pitch angular velocity peaks multiple times occurs. With respect to such pitch behavior in which multiple peaks occur with a time difference within a relatively short period, an additional pitch moment is applied with a time difference by controlling the braking forces of the front wheels 3a and 3b and the rear wheels 3c and 3d so as to suppress this pitch behavior (peak portion).

[0037] For example, as shown in FIG. 7, when pitch behavior (TS1, TS2) occurs when the front wheels pass over a convex road surface and pitch behavior occurs until the displacement of the suspension device returns to 0 after the front wheels have passed over the convex road surface, an additional pitch moment is applied so as to suppress the pitch behavior in TS1 and the pitch behavior in Ts3 that occur subsequently. As shown in FIG. 8, when an additional pitch moment is applied by controlling the braking force by the friction brake device (brake device 30a) so as to suppress two successive pitch behaviors, the additional pitch moment is applied in two peak shapes in accordance with the pitch behavior. When the additional pitch moment is applied only by the friction brake devices (brake devices 30a to 30d) in this way, the braking force of the entire vehicle also changes in response to the additional moment due to the friction braking force within a relatively short period.

[0038] In the present embodiment, not only is an additional pitch moment applied by controlling the braking force by the friction brake device, but an additional pitch moment is also applied by controlling the regenerative braking force. For example, as shown in FIG. 9, when pitch behavior occurs twice successively when the front wheels pass over a convex road surface, in the present embodiment, the total value of the friction braking force and the regenerative braking force is set to Total Brake required by, for example, a brake operation or the like, and the regenerative braking force at the rear is controlled so as to change smoothly during the occurrence of the two friction braking forces Fbf.

[0039] As a result, changes in the braking force of the entire vehicle are suppressed, fluctuations in acceleration in a short period of time due to pitch suppression control can be suppressed, and the discomfort felt by the driver can be reduced. Also, for example, when suppressing the pitch behavior that occurs when the front wheels 3a and 3b pass over a convex road surface, if the front wheels 3a and 3b are braked by the brake devices 30a and 30b, by applying regenerative braking force to the rear wheels 3c and 3d, excessive pitch suppression due to applying regenerative braking force can be suppressed.

[0040] In this way, since the regenerative braking force is also independently controlled for the front wheels 3a, 3b and the rear wheels 3c, 3d, the total braking force combining the frictional braking force and the regenerative braking force can also be independently controlled for the front wheels 3a, 3b and the rear wheels 3c, 3d. An appropriate additional moment can be applied corresponding to the pitch moment generated when passing over a step such as a convex road surface, and the effect of suppressing pitch behavior can be exerted.

[0041] Also, in this embodiment, the conditions of Table A for determining the occurrence of pitch behavior are based on the rotational acceleration of the wheels 3a to 3d based on the rotational speeds of the wheels 3a to 3d, the longitudinal acceleration of the vehicle 1, and the pitch rate of the vehicle 1 to determine the passage of the convex road surface of the vehicle 1. Therefore, the occurrence of pitch behavior can be easily determined. Also, when the conditions of Table A are satisfied, that is, based on the vehicle speed when passing over a convex road surface, the braking time for executing pitch suppression control is set. Therefore, pitch suppression control by braking control can be performed for an appropriate time, and necessary and sufficient pitch suppression control can be enabled.

[0042] Also, in pitch suppression control, since the total braking force is set to change linearly, while suppressing changes in the braking force of the entire vehicle, the total braking force xxF at the start of braking and the total braking force xxF2 at the end of braking can be appropriately set respectively to increase the pitch suppression effect. The description of the embodiment is finished above, but the aspects of the present invention are not limited to the above embodiment. For example, the conditions of Table A and various threshold values described above may be appropriately set according to the type of vehicle, etc.

[0043] Further, in the above-described embodiment, when the front wheels 3a and 3b and the rear wheels 3c and 3d of the vehicle 1 pass over a convex road surface, or when one of the front wheels 3a and 3b and the rear wheels 3c and 3d passes over a convex road surface, in such a situation, an additional pitch moment is applied by controlling the frictional braking force and the regenerative braking force within a predetermined time, and it has been described that the pitch behavior is suppressed while suppressing fluctuations in the longitudinal acceleration of the vehicle. However, the present invention is not limited to such a situation. In the present embodiment, since fluctuations in the total value of the frictional braking force and the regenerative braking force are suppressed in the braking time Time Brake set based on the vehicle speed when the conditions of Table A are satisfied, the same effect can be obtained even when the pitch angular velocity fluctuates a plurality of times other than twice within the time period.

[0044] The present invention can be widely applied to a vehicle capable of independently controlling at least the frictional braking force and the regenerative braking force of the front wheels and the rear wheels.

Explanation of Signs

[0045] 1 Vehicle 3a, 3b Front wheels (wheels) 3c, 3d Rear wheels (wheels) 5 Front motor (regenerative braking device) 6 Rear motor (regenerative braking device) 10 Attitude control device 11 Suspension device 30a~30d Brake devices (frictional braking devices) 31 Brake control unit (braking control unit) 33a~33d Wheel speed sensors (speed detection units) 35 Longitudinal acceleration sensor (longitudinal acceleration detection unit) 36 Pitch rate sensor (pitch rate detection unit)

Claims

1. A vehicle in which front, rear, left, and right wheels are suspended by a suspension device having anti-dive and anti-lift geometry, friction braking devices respectively provided on the front, rear, left, and right wheels, a regenerative braking device that respectively applies regenerative braking forces to at least the front and rear wheels among the front, rear, left, and right wheels, a braking control unit that applies a frictional braking force independently to at least the front and rear wheels by controlling the operation of the front, rear, left, and right frictional braking devices, and applies a regenerative braking force independently to the front and rear wheels by controlling the operation of the regenerative braking device, a speed detection unit that respectively detects the rotational speeds of the front, rear, left, and right wheels, a front-rear acceleration detection unit that detects the front-rear acceleration of the vehicle, a pitch rate detection unit that detects the pitch rate of the vehicle, The braking control unit executes cooperative control to suppress the pitch behavior of the vehicle by applying an additional pitch moment by controlling the operation of the friction braking device and the regenerative braking device based on the vehicle running state, When an additional pitch moment is applied a plurality of times within a predetermined time by controlling the operation of the friction braking device, during and between the operations of the plurality of friction braking devices, the change amount of the total braking force of the braking force by the friction braking device and the braking force by the regenerative braking device is suppressed to a predetermined value or less A vehicle attitude control device characterized by the above.

2. The braking control unit executes the cooperative control for the pitch behavior respectively generated when the front wheels of the vehicle pass over a convex road surface and when the rear wheels pass over the convex road surface. The vehicle attitude control device according to claim 1, characterized by the above.

3. The braking control unit executes the cooperative control for the pitch of the first cycle and the pitch behavior of the second cycle generated when either the front or rear wheels of the vehicle climb over a convex road surface. The vehicle attitude control device according to claim 1, characterized by the above.

4. The braking control unit determines passage of the vehicle over a convex road surface based on the rotational acceleration of the wheel based on the rotational speed of the wheel, the longitudinal acceleration of the vehicle, and the pitch rate of the vehicle, calculates the braking time in the coordinated control based on the vehicle speed at the time when passage over the convex road surface is determined The vehicle attitude control device according to claim 1, characterized by the above.

5. The braking control unit sets the total braking force to change linearly from the time when passage over the convex road surface is determined until the braking time elapses. The vehicle attitude control device according to claim 4, characterized by the above.

Images