JP2004276711A - Vehicle behavior control device - Google Patents

Abstract

An object of the present invention is to perform behavior control suitable for a situation where a forced external force acts due to a collision of a vehicle, and to accurately control the behavior of the vehicle even in a situation where a forced external force acts.
When there is a risk of collision of a vehicle (S40, 90), the target braking force Fssfo of the front wheel on the outside of the turn and the entire vehicle are reduced in a region where the spin amount SS and the drift-out state DS are smaller than normal. When the target braking force Fsall is calculated to be a positive value, the behavior control is easily started (S96, 98). When the vehicle collides (S20, 102), the target braking force Fsfo, Fsfi, Fsfi, The behavior control amount is increased by increasing and correcting Fsro and Fsri by Ka times, respectively (S102 to S106).
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a behavior control device for a vehicle, and more particularly to a behavior control device capable of coping with a situation in which an external force not caused by the motion of the vehicle acts on the vehicle.
[0002]
[Prior art]
As one of the behavior control devices of a vehicle such as an automobile, for example, as described in Patent Document 1 below filed by the present applicant, the vehicle speed is controlled based on a target vehicle speed for ensuring running stability of the vehicle. Calculates the target deceleration, determines the behavior of the vehicle based on the target deceleration, and determines the behavior of the vehicle. If the behavior of the vehicle deteriorates, controls the braking force of each wheel to stabilize the behavior of the vehicle. 2. Description of the Related Art A behavior control device that performs behavior control for making a computer readable is conventionally known.
[Patent Document 1]
JP 2001-82200 A
[0003]
[Problems to be solved by the invention]
In particular, the latter type of behavior control device detects a state quantity of the vehicle that changes due to the motion of the vehicle, and a behavior index value indicating the behavior of the vehicle such as a spin state quantity or a drift-out state quantity based on the state quantity of the vehicle. Is calculated, and the vehicle behavior is stabilized by the braking force when the behavior index value exceeds the reference value.
[0004]
However, the behavior of the vehicle may be disturbed even when the vehicle is collided and a forcing force is applied from the outside, and in such a case, the state quantity of the vehicle changes more rapidly than the change accompanying normal traveling. Therefore, the behavior index value is calculated based on the detected state quantity of the vehicle, and when the behavior index value exceeds the reference value, even if the vehicle behavior is stabilized by the braking force, the behavior of the vehicle deteriorates rapidly. On the other hand, the stabilization control may not be in time, and the stabilization control amount of the vehicle behavior may be insufficient, so that the vehicle may not be effectively stabilized.
[0005]
The present invention is configured to detect a state quantity of a vehicle, calculate a behavior index value based on the state quantity of the vehicle, and stabilize vehicle behavior by a braking force when the behavior index value exceeds a reference value. The present invention has been made in view of the above-described problem in the conventional behavior control device, and a main problem of the present invention is to perform behavior control suitable for a situation where a forced external force is applied, It is to accurately control the behavior of a vehicle even in a situation where a forced external force acts.
[0006]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION According to the present invention, the above-described main object is a vehicle behavior control apparatus that performs the behavior control of determining the behavior of the vehicle and stabilizing the behavior of the vehicle when the behavior of the vehicle is deteriorated. An external force determining means for determining a state in which an external force not caused by the movement of the vehicle acts on the vehicle; and a control suitable for a situation in which the external force acts on the vehicle when the external force acts on the vehicle. And a control change means for changing the vehicle behavior.
[0007]
According to the present invention, in order to effectively achieve the above-described main object, in the configuration of the above-mentioned claim 1, the external force determining means determines a situation in which there is a high possibility that the external force acts on a vehicle. When the control change means determines that the situation where the external force is likely to act on the vehicle is high, the behavior is such that the behavior control is easily started compared to a situation where the possibility that the external force acts on the vehicle is low. The control is configured to be changed (the configuration of claim 2).
[0008]
According to the present invention, in order to effectively achieve the above-described main object, in the configuration of claim 1 or 2, the external force determining means determines that the external force has acted on a vehicle, and The control change means is configured to change the behavior control such that when it is determined that the external force acts on the vehicle, the behavior control amount is larger than when the external force is not acting on the vehicle (claim 3). Configuration).
[0009]
According to the present invention, in order to effectively achieve the above-described main object, in the configuration of the above-mentioned claim 3, the control changing means determines that the external force is applied when it is determined that the external force acts on the vehicle. It is configured to estimate the magnitude and change the behavior control so that the greater the magnitude of the estimated external force is, the larger the behavior control amount is.
[0010]
Further, according to the present invention, in order to effectively achieve the above-described main object, in the configuration of claim 1, the control change unit estimates a slip angle of the vehicle, and the external force acts on the vehicle. When the magnitude of the slip angle of the vehicle is equal to or larger than the reference value in the case where it is determined that the vehicle speed is larger than the reference value, the increase of the behavior control amount is stopped.
[0011]
Function and effect of the present invention
According to the configuration of the first aspect, the situation where an external force not caused by the motion of the vehicle acts on the vehicle is determined, and when the external force acts on the vehicle, the behavior control is suitable for the situation where the external force acts on the vehicle. The control is changed to that of the conventional behavior control device in which even when external force not due to the motion of the vehicle acts on the vehicle, the external force acts on the vehicle as compared with the conventional behavior control device in which this is not considered. Therefore, the behavior of the vehicle can be appropriately stabilized.
[0012]
Further, according to the configuration of the second aspect, it is determined that there is a high possibility that the external force acts on the vehicle, and when it is determined that there is a high possibility that the external force acts on the vehicle, the external force is applied to the vehicle. The behavior control is changed so that the behavior control is easily started as compared with the situation where the possibility of acting on the vehicle is low, so that the behavior control is performed in a normal manner when the external force acts on the vehicle and the behavior of the vehicle deteriorates. , The delay of the start of the behavior control for the change in the behavior of the vehicle can be reduced, and the deterioration of the behavior of the vehicle can be effectively suppressed.
[0013]
According to the configuration of the third aspect, it is determined that the external force has acted on the vehicle, and when it is determined that the external force has acted on the vehicle, the behavior is smaller than when the external force is not acting on the vehicle. Since the behavior control is changed so that the control amount is increased, the behavior control effect is reduced compared to the case where the behavior control is executed with the normal control amount without determining that the external force has acted on the vehicle. The height of the vehicle, thereby effectively stabilizing the behavior of the vehicle.
[0014]
According to the configuration of the fourth aspect, when it is determined that the external force has acted on the vehicle, the magnitude of the external force is estimated, and the behavior control amount increases as the estimated external force increases. Since the behavior control is changed, the behavior control amount can be optimally controlled according to the magnitude of the external force acting on the vehicle.
[0015]
According to the fifth aspect of the present invention, the slip angle of the vehicle is estimated, and when it is determined that the external force has acted on the vehicle, the behavior when the magnitude of the slip angle of the vehicle is equal to or greater than a reference value is determined. Since the increase in the control amount is stopped, it is possible to reliably prevent the behavior control amount from increasing in a situation where the slip angle of the vehicle is large.
[0016]
Preferred embodiments of the means for solving the problems
According to one preferred aspect of the present invention, in the configuration of claim 1, the situation in which an external force not caused by the movement of the vehicle acts on the vehicle is determined based on a relative distance and a relative speed to a surrounding moving body. (Preferred embodiment 1).
[0017]
According to another preferred embodiment of the present invention, in the configuration of the above-mentioned claim 2, the situation in which there is a high possibility that an external force not caused by the movement of the vehicle acts on the vehicle is a relative distance and a relative distance to the surrounding moving body. The determination is made based on the speed (preferred mode 2).
[0018]
According to another preferred aspect of the present invention, in the configuration of claim 3, the fact that the external force not caused by the movement of the vehicle acts on the vehicle means that the external force not caused by the movement of the vehicle acts on the vehicle. In a situation in which it is determined that there is a high possibility, the determination is made based on the fact that the rate of change of the vehicle state quantity is greater than or equal to a magnitude that does not occur during normal running of the vehicle (preferred mode 3).
[0019]
According to another preferred aspect of the present invention, in the configuration of the fourth aspect, the magnitude of the external force is configured to be estimated based on a change rate of the vehicle state quantity (preferred aspect 4).
[0020]
According to another preferred embodiment of the present invention, in the configuration of the above-mentioned preferred embodiment 4, the magnitude of the external force is such that the state of the vehicle at the time when it is determined that the external force not caused by the movement of the vehicle has acted on the vehicle. It is configured to be estimated based on the rate of change of the amount (preferred embodiment 5).
[0021]
According to another preferred aspect of the present invention, in the configuration of the fifth aspect, when the magnitude of the slip angle of the vehicle is equal to or larger than the reference value, the behavior control amount is gradually reduced (preferably). Aspect 6).
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention (hereinafter, simply referred to as embodiments) will be described in detail with reference to the accompanying drawings.
[0023]
FIG. 1 is a schematic configuration diagram showing one preferred embodiment of a vehicle behavior control device according to the present invention.
[0024]
1, 10FL and 10FR denote left and right front wheels of the vehicle 12, respectively, and 10RL and 10RR denote left and right rear wheels which are driving wheels of the vehicle, respectively. The left and right front wheels 10FL and 10FR, which are both driven wheels and steering wheels, are driven via tie rods 18L and 18R by a rack-and-pinion type power steering device 16 driven in response to the driver turning the steering wheel 14. Steered.
[0025]
The braking force of each wheel is controlled by controlling the braking pressure of the wheel cylinders 24FR, 24FL, 24RR, 24RL by the hydraulic circuit 22 of the braking device 20. Although not shown in the figure, the hydraulic circuit 22 includes an oil reservoir, an oil pump, various valve devices such as a pressure increasing / decreasing control valve for increasing / decreasing a pressure in the wheel cylinder, and the like. Normally, the duty ratio is controlled by a master cylinder 28 which is driven in response to a depression operation of the brake pedal 26 by the driver, and a pressure increase / decrease control valve is controlled by an electronic control unit 30 as required in detail later. Is controlled by
[0026]
Each of the wheels 10FR to 10RL is provided with a wheel speed sensor 32FR to 32RL for detecting a wheel speed Vwi (i = fr, fl, rr, rl) of a corresponding wheel as a peripheral speed, and a steering column to which a steering wheel 14 is connected. Is provided with a steering angle sensor 34 for detecting the steering angle θ.
[0027]
The vehicle 12 is provided with a yaw rate sensor 36 for detecting a yaw rate γ of the vehicle, a longitudinal acceleration sensor 38 for detecting a longitudinal acceleration Gx, a lateral acceleration sensor 40 for detecting a lateral acceleration Gy, and a vehicle speed sensor 42 for detecting a vehicle speed V. ing. The steering angle sensor 34, the yaw rate sensor 36, and the lateral acceleration sensor 40 detect the steering angle, the yaw rate, and the lateral acceleration, respectively, with the left turning direction of the vehicle being positive.
[0028]
Further, the radar sensors 44 to 50 for detecting the front and rear and left and right vehicles of the own vehicle, respectively, and detecting the relative distance Lre and the relative speed Vre to the vehicle using radio waves such as millimeter waves and laser light. Is provided.
[0029]
As shown, a signal indicating the wheel speed Vwi detected by the wheel speed sensors 32FR to 32RL, a signal indicating the steering angle θ detected by the steering angle sensor 34, a signal indicating the yaw rate γ detected by the yaw rate sensor 36, A signal indicating the longitudinal acceleration Gx detected by the acceleration sensor 38, a signal indicating the lateral acceleration Gy detected by the lateral acceleration sensor 40, a signal indicating the vehicle speed V detected by the vehicle speed sensor 42, and detected by the radar sensors 44 to 50 A signal indicating the relative distance Lre and the relative speed Vre is input to the electronic control unit 30.
[0030]
Although not shown in detail in the figure, the electronic control device 30 has, for example, a general configuration in which a CPU, a ROM, a RAM, and an input / output port device are connected to each other by a bidirectional common bus. Includes microcomputer.
[0031]
The electronic control unit 30 determines the spin state amount SS indicating the degree of spin of the vehicle and the drift-out state of the vehicle based on the vehicle state amount that changes as the vehicle travels, according to the flowcharts illustrated in FIGS. Calculate the drift-out state amount DS indicating the degree, and set the target slip ratio Rsti (i = fr, fl, rr, i) of each wheel of the behavior control for stabilizing the behavior of the vehicle based on the spin state amount SS and the drift-out state amount DS. rl), and the braking force of each wheel is controlled so that the slip rate of each wheel becomes the target slip rate Rsti, thereby stabilizing the behavior of the vehicle.
[0032]
Further, the electronic control unit 30 determines whether there is a risk that the surrounding vehicle may collide with the own vehicle based on the relative distance Lre and the relative speed Vre with respect to the surrounding vehicle detected by the radar sensors 44 to 50, and When it is determined that there is a possibility that the behavior control is started, the behavior control is made easier to start as compared with the normal state, and the behavior control amount is increased in view of the same vehicle state quantity.
[0033]
Further, in a situation where it is determined that there is a risk that a surrounding vehicle may collide with the own vehicle, the electronic control unit 30 may change the vehicle state quantity at a change rate that does not occur during normal running of the vehicle. It is determined that the vehicle has collided, and the behavior control amount is further increased as compared with the case where it is determined that there is a possibility of collision.
[0034]
Next, the main routine of the behavior control in the illustrated embodiment will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 2 is started by closing an ignition switch (not shown), and is repeatedly executed at predetermined time intervals.
[0035]
First, in step 10, a signal or the like indicating the wheel speed Vwi is read. At the start of the control according to the flowchart shown in FIG. 2, the flag Fc is reset to 0 prior to step 10, and the increase correction coefficient Ka calculated in step 104 described later is reset to 1.
[0036]
In step 20, it is determined whether or not the vehicle has collided. If an affirmative determination is made, the flag Fc is set to 2 in step 30, and if a negative determination is made, the process proceeds to step 40. .
[0037]
In this case, the determination as to whether or not the vehicle has collided may be made in any manner known in the art. For example, a situation where the flag Fc is 1, that is, there is a possibility that the vehicle is collided. In some situations, the absolute value of the rate of change ΔGx of the longitudinal acceleration Gx of the vehicle, the absolute value of the rate of change ΔGy of the lateral acceleration Gy of the vehicle, or the absolute value of the rate of change Δγ of the yaw rate γ of the vehicle, or any of them The determination may be made by determining whether or not the weighted sum ΔM has a size that does not occur during normal running of the vehicle. The determination as to whether or not the vehicle has collided may be detected by a load sensor (not shown in FIG. 1) attached to the vehicle body.
[0038]
In step 40, it is determined whether or not there is a risk that the surrounding vehicle may collide with the own vehicle based on the relative distance Lre and the relative speed Vre with respect to the surrounding vehicle detected by the radar sensors 44 to 50, When a negative determination is made, the flag Fc is reset to 0 in step 50, and when an affirmative determination is made, the flag Fc is set to 1 in step 60 and braking force can be applied to each wheel. Preparation (for example, pressurization of the wheel cylinder to such an extent that the brake shoe lightly contacts the brake rotor) is performed.
[0039]
In this case, the determination as to whether or not there is a risk that the surrounding vehicles may collide with the own vehicle may be made in any manner known in the art. For example, the larger the relative speed Vre, the smaller the reference value. The value Lo may be calculated, and it may be determined that there is a risk of collision when the relative distance Lre is equal to or less than the reference value Lo.
[0040]
In step 70, it is determined whether or not a permission condition for behavior control is satisfied, for example, whether or not the vehicle speed V is equal to or higher than a reference value Vo (positive constant), and a negative determination is made. In this case, the control according to the routine shown in FIG. 2 is temporarily terminated, and when an affirmative determination is made, the routine proceeds to step 80.
[0041]
In step 80, the target slip ratio Rsti of each wheel for stabilizing the behavior of the vehicle is calculated in accordance with the routine shown in FIG. 3, and in step 110, the target slip ratio Rsti of all wheels is set to 0. Is determined, that is, it is determined whether or not it is not necessary to apply a braking force for stabilizing the behavior of the vehicle. If an affirmative determination is made, the process directly proceeds to step 130, and a negative determination is made. Is performed, in step 120, the braking force of each wheel is controlled so that the slip rate of each wheel becomes the target slip rate Rsti.
[0042]
In step 130, it is determined whether the behavior control is being performed and the end condition of the behavior control is satisfied, for example, whether the vehicle speed V has fallen below the reference value Vo, and a negative determination is made. If the answer is YES, the control according to the routine shown in FIG. 2 is temporarily terminated, and if an affirmative determination is made, the flag Fc is reset to 0 and the increase correction coefficient Ka is reset to 1 in step 140. .
[0043]
In step 82 of the target slip ratio Rsti calculation routine shown in FIG. 3, the deviation of the lateral acceleration as the deviation Gy-γV between the lateral acceleration Gy and the product γV of the vehicle speed V and the yaw rate γ, that is, the vehicle slip acceleration Vyd. Is calculated, and the side slip acceleration Vyd is integrated to calculate the side slip speed Vy of the vehicle body. Further, the slip angle β of the vehicle body is obtained as a ratio Vy / Vx of the side slip speed Vy of the vehicle body to the longitudinal speed Vx (= vehicle speed V) of the vehicle body. Is calculated.
[0044]
In step 84, the spin amount SV is calculated as the linear sum K1β + K2Vyd of the slip angle β and the skid acceleration Vyd of the vehicle body with K1 and K2 as positive constants, and the turning direction of the vehicle is determined based on the sign of the yaw rate γ. Then, the spin state amount SS is calculated as SV when the vehicle turns left, and as −SV when the vehicle turns right. When the calculation result is a negative value, the spin state amount is set to 0. The spin amount SV may be calculated as a linear sum of the vehicle body slip angle β and its differential value βd.
[0045]
In step 86, the actual steering angle δ of the front wheels is calculated based on the steering angle θ, the target yaw rate γe is calculated according to the following equation 1 using H as a wheel base and Kh as a stability factor, and T is a time constant. Then, the estimated yaw rate γt of the vehicle is calculated based on the vehicle speed V and the steering angle θ using s as a Laplace operator according to the following equation 2. The target yaw rate γe may be calculated in consideration of the lateral acceleration Gy of the vehicle in consideration of a dynamic yaw rate.
γe = Vδ / (1 + KhV ² ) H ... (1)
γt = γe / (1 + Ts) (2)
[0046]
In step 88, the drift value DV is calculated in accordance with the following equation (3), and the turning direction of the vehicle is determined based on the sign of the yaw rate γ. At the time of right turn, it is calculated as -DV. When the calculation result is a negative value, the drift-out state amount is set to zero. The drift value DV may be calculated according to the following equation (4).
DV = (γt−γ) (3)
DV = H (γt−γ) / V (4)
[0047]
In step 90, it is determined whether or not the flag Fc is 0, that is, whether or not the vehicle is running in a normal situation without a possibility or collision of the vehicle. When the determination is negative, the process proceeds to step 96, and when the determination is affirmative, the process proceeds to step 92.
[0048]
In step 92, the target braking force Fssfo of the front wheel outside the turning is calculated from the map corresponding to the graph shown by the solid line in FIG. 4 based on the spin state amount SS, and in step 94, the drift-out state Based on the amount DS, a target braking force Fsall of the entire vehicle is calculated from a map corresponding to the graph shown by the solid line in FIG.
[0049]
In step 96, the target braking force Fsfo of the turning outer front wheel is calculated from the map corresponding to the graph shown by the broken line in FIG. 4 based on the spin amount SS, and in step 98, the drift-out state is set. Based on the amount DS, a target braking force Fsall of the entire vehicle is calculated from a map corresponding to the graph shown by the broken line in FIG.
[0050]
In step 100, the distribution ratio of the inside rear wheel is Ksri (generally, a positive constant greater than 0.5), and the outside front wheel, inside front wheel, outside rear wheel, and outside turn are calculated according to the following equation (5). The target braking forces Fsfo, Fsfi, Fsro, Fsri for the inner rear wheel are calculated.
Fsfo = Fssfo
Fsfi = 0
Fsro = (Fsall-Fssfo) (1-Ksri)
Fsri = (Fsall-Fssfo) Ksri (5)
[0051]
In step 102, it is determined whether or not the flag Fc is 2, that is, whether or not the vehicle has collided. If a negative determination is made, the process directly proceeds to step 108, and an affirmative determination is made. If so, the process proceeds to step 104.
[0052]
In step 104, an increase correction coefficient Ka (a value larger than 1) is calculated based on the degree of impact of the collision, for example, the larger the weighted sum ΔM is, the larger the weighted sum ΔM is. The target braking forces Fsfo, Fsfi, Fsro, and Fsri of the front wheel, the turning inner front wheel, the turning outer rear wheel, and the turning inner rear wheel are each corrected to increase Ka times.
[0053]
In step 108, the turning direction of the vehicle is determined based on the sign of the yaw rate γ, and the inner and outer turning wheels are specified. Based on the specified result, the target braking force Fbsi (i = fr, fl) for the behavior control of each wheel is determined. , Rr, rl) are calculated according to the following equations (6) and (7) when the vehicle is turning left and when turning right, respectively, and based on the target braking force Fbsi, the target slip ratio Rsti (i = fr) of each wheel. , Fl, rr, rl) are calculated.
[0054]
Fbsfr = Fsfo
Fbsfl = Fsfi
Fbsrr = Fsro
Fbsrl = Fsri (6)
Fbsfr = Fsfi
Fbsfl = Fsfo
Fbsrr = Fsri
Fbsrl = Fsro (7)
[0055]
Thus, according to the illustrated embodiment, in steps 82 and 84, the spin state quantity SS indicating the degree of spin of the vehicle is calculated, and in steps 86 and 88, the drift state quantity SS indicating the degree of drift out of the vehicle is calculated. DS is calculated, and in steps 92 to 98, a target braking force Fssfo of the turning outer front wheel for spin suppression is calculated based on the spin state amount SS, and drift-out is suppressed based on the drift-out state amount DS. The target braking force Fsall of the entire vehicle is calculated, and in step 100, the target braking force Fbsi of each wheel of the behavior control is performed based on the target braking force Fssfo for suppressing the spin and the target braking force Fsall for suppressing the drift-out. Is calculated, and in step 108, each wheel for achieving the target braking force Fbsi Target slip ratio Rsti is calculated.
[0056]
In this case, during a normal running in which the vehicle is not likely to collide or is not collided, a negative determination is made in steps 20 and 40, a flag Fc is reset to 0 in step 50, and the behavior control is performed. If the permission condition is satisfied, an affirmative determination is made in step 70, and an affirmative determination is made in step 90 of the subroutine of step 80, whereby in step 92 the target braking force of the turning outer front wheel is determined. Fssfo is calculated from the map corresponding to the graph shown by the solid line in FIG. 4 based on the spin state amount SS, and in step 94, the target braking force Fsall of the entire vehicle is calculated based on the drift-out state amount DS in FIG. Is calculated from the map corresponding to the graph shown by the solid line.
[0057]
Then, in step 100, the target braking force Fsfo of each wheel of the behavior control is calculated on the basis of the target braking force Fssfo and the target braking force Fsall, and a negative determination is made in step 102. A target slip ratio Rsti of each wheel for achieving the target braking force Fsfo and the like is calculated. If the behavior of the vehicle is deteriorating, a negative determination is made in step 110, and a braking force control is performed in step 120. Is executed, the behavior of the vehicle is stabilized.
[0058]
For example, when the vehicle is in a spin state, the spin is suppressed by applying a braking force to the turning outer front wheel and applying a yaw moment in the spin suppression direction to the vehicle, and when the vehicle is in a drift-out state, the left and right rear wheels The braking force is applied to decelerate the vehicle, and the yaw moment in the turning assist direction is applied to the vehicle, so that drift-out is suppressed.
[0059]
On the other hand, when there is a risk of collision of the vehicle, a negative determination is made in step 20, an affirmative determination is made in step 40, and the flag Fc is set to 1 in step 60. When the negative determination is made in step 90, the target braking force Fssfo of the turning outer front wheel is determined in step 96 based on the spin state amount SS in the map corresponding to the graph shown by the broken line in FIG. In step 98, the target braking force Fsall of the entire vehicle is calculated from the map corresponding to the graph shown by the broken line in FIG. 5 based on the drift-out state amount DS.
[0060]
Therefore, when there is a risk of collision of the vehicle, it is not determined that the condition for permitting the behavior control in step 70 is satisfied, and it is determined that the condition for permitting the behavior control is satisfied. Since the target braking force Fssfo of the turning outer front wheel and the target braking force Fsall of the entire vehicle are calculated to be positive values in the region where the SS and the drift-out state amount DS are small, the behavior control is easily started, thereby causing the vehicle to collide. In such a case, the delay of the behavior control can be effectively reduced.
[0061]
Further, according to the illustrated embodiment, when there is a risk of collision of the vehicle, preparation is made in step 60 to apply braking force to each wheel. The delay of the behavior control in the above can be effectively reduced.
[0062]
If the vehicle has collided, an affirmative determination is made in step 20, the flag Fc is set to 2 in step 30, and a negative determination is made in step 90. In step 96, the target braking force Fssfo of the turning outer front wheel is calculated from the map corresponding to the graph shown by the broken line in FIG. 4 based on the spin amount SS, and in step 98, the target braking force of the entire vehicle is calculated. Fsall is calculated from the map corresponding to the graph shown by the broken line in FIG. 5 based on the drift-out state amount DS.
[0063]
Then, an affirmative determination is made in step 102, and an increase correction coefficient Ka is calculated in step 104 based on the degree of impact of the collision, for example, the weighted sum ΔM so as to increase as the weighted sum ΔM increases. At 106, the target braking forces Fsfo, Fsfi, Fsro, and Fsri of the turning outer front wheel, the turning inner front wheel, the turning outer rear wheel, and the turning inner rear wheel are respectively corrected to be increased by Ka times.
[0064]
Therefore, according to the illustrated embodiment, when the vehicle collides, the target braking forces Fsfo, Fsfi, Fsro, and Fsri are increased and corrected, and the behavior of the vehicle is stabilized by the increased and corrected behavior control amount. Even if the behavior of the vehicle suddenly deteriorates significantly due to the collision of the vehicle and the forced external force acts, the deterioration of the behavior of the vehicle is suppressed or stabilized more effectively than in the past. Can be done.
[0065]
In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to the above embodiment, and various other embodiments are possible within the scope of the present invention. Some will be apparent to those skilled in the art.
[0066]
For example, in the above-described embodiment, when the vehicle collides, the behavior control amount is increased and corrected regardless of the size of the slip angle β of the vehicle body. As described above, when an affirmative determination is made in step 202, a determination is made in step 103 as to whether the absolute value of the slip angle β of the vehicle body is greater than or equal to a reference value βo (positive constant). When an affirmative determination is made, the correction is made so as to proceed directly to step 108 without executing steps 104 and 106, whereby the correction is made so that the roll angle of the vehicle body is prevented from increasing by, for example, the spin suppression control. Alternatively, when the magnitude of the slip angle of the vehicle body is very large, the behavior control amount may be modified so as to be gradually reduced.
[0067]
Further, in the above-described embodiment, when there is a possibility that the vehicle will collide, it is not determined whether or not the condition for permitting the behavior control is satisfied. Then, for example, the permission condition of the behavior control may be relaxed by reducing the reference value Vo, and thereafter, the determination may be made so as to determine whether the permission condition of the behavior control is satisfied.
[0068]
In the above-described embodiment, the possibility of a collision is determined, but when the possibility of a collision is determined, no prediction is made as to what effect the own vehicle will have. If it is determined that there is a possibility of the vehicle being inferred, it is predicted whether the approaching situation of the surrounding vehicles to the own vehicle is a situation that causes the own vehicle to spin or a situation that causes a drift-out, and based on the prediction result, It may be modified so that only one of the spin control (FIG. 4) and the drift-out control (FIG. 5) is easily started, and only one of the spin control amount and the drift-out control amount is increased and corrected. It may be modified so that:
[0069]
Further, in the above-described embodiment, the spin state amount SS and the drift-out state amount DS are calculated in steps 82 to 88, and the behavior of the vehicle is stabilized based on these state amounts in steps 92 to 98. The target braking force is calculated in step 100, and the target braking force of each wheel is calculated in step 100. However, the behavior control itself does not form the gist of the present invention. It may be carried out in any known manner. The target slip ratio Rsti is calculated as the target control amount of each wheel, and the braking force of each wheel is controlled based on the target slip ratio Rsti. The braking pressure may be calculated and modified so that the braking force of each wheel is controlled based on the target braking pressure.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing one preferred embodiment of a vehicle motion control device according to the present invention.
FIG. 2 is a general flowchart showing a main routine of behavior control in the illustrated embodiment.
FIG. 3 is a flowchart showing a routine for calculating a target slip ratio Rsti of each wheel in step 80 of the flowchart shown in FIG. 2;
FIG. 4 is a graph showing a relationship between a spin state amount SS and a target braking force Fssfo of a turning outer front wheel in a normal case (solid line) and in a case where there is a possibility of collision of a vehicle (dashed line).
FIG. 5 is a graph showing a relationship between a drift-out state amount DS and a target braking force Fsall of the entire vehicle in a normal case (solid line) and in a case where the vehicle may possibly collide (dashed line).
FIG. 6 is a flowchart showing a main part of a routine for calculating a target slip angle ratio Rsti of each wheel in a modified example.
[Explanation of symbols]
10FR-10RL ... Wheel
20 ... Brake device
28 ... Master cylinder
30 ... Electric control device
32FR-32RL ... wheel speed sensor
34 …… Steering angle sensor
36 ... Yaw rate sensor
38 ... longitudinal acceleration sensor
40 ... lateral acceleration sensor
42 ... Vehicle speed sensor
44-50 ... Radar sensor

Claims (5)

A vehicle behavior control device that determines the behavior of a vehicle and performs behavior control to stabilize the behavior of the vehicle when the behavior of the vehicle deteriorates, and determines a situation in which an external force not due to the motion of the vehicle acts on the vehicle. A vehicle behavior control device comprising: an external force determination unit; and a control change unit that changes the behavior control to a control suitable for a situation in which the external force acts on the vehicle when the external force acts on the vehicle. The external force determining means determines a situation where the external force is likely to act on the vehicle, and the control changing means determines that the external force is likely to act on the vehicle when the external force is determined to be a situation where the external force is likely to act on the vehicle. 2. The behavior control device for a vehicle according to claim 1, wherein the behavior control is changed so that the behavior control is easily started as compared to a situation in which there is a low possibility that the behavior control is performed. The external force determining means determines that the external force has acted on the vehicle, and the control change means has a behavior control when it is determined that the external force has acted on the vehicle as compared to when the external force is not acting on the vehicle. 3. The behavior control device for a vehicle according to claim 1, wherein the behavior control is changed to increase the amount. The control change unit estimates the magnitude of the external force when it is determined that the external force acts on the vehicle, and changes the behavior control such that the behavior control amount increases as the estimated external force increases. The vehicle behavior control device according to claim 3, wherein: The control change means estimates the slip angle of the vehicle, and increases the behavior control amount when the magnitude of the slip angle of the vehicle is equal to or larger than a reference value when it is determined that the external force has acted on the vehicle. The vehicle behavior control device according to claim 3 or 4, wherein the operation is stopped.

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