JP5430169B2 - Vehicle behavior support apparatus and vehicle behavior support method - Google Patents

Description

  The present invention relates to a vehicle behavior support apparatus and a vehicle behavior support method that support vehicle behavior control during turning.

  In general, when the steering wheel is steered by the driver while the vehicle is traveling, the turning angle (also referred to as “tire angle”) of the steered wheels is adjusted to an angle corresponding to the steering angle of the steering wheel. At this time, as shown in FIG. 9, the lateral force FS based on the frictional force generated between the steered wheel 30 and the road surface is applied to the steered wheel 30 in the width direction of the steered wheel 30 (that is, the direction of the steered wheel 30). In a direction substantially perpendicular to the direction). The vehicle turns using the cornering force F of the component in the direction substantially orthogonal to the traveling direction of the lateral force FS applied to the steered wheels 30.

  The following relationship exists between the cornering force F that acts when the vehicle turns and the turning angle of the steered wheels 30. That is, as shown in FIG. 10, when the turning angle σ of the steered wheels 30 is relatively small, the cornering force F gradually increases as the turning angle σ increases, and the turning angle σ becomes the road surface limit. When the steering angle σmax is reached, the cornering force F becomes the largest value. When the turning angle σ is larger than the road surface limit steering angle σmax, the tire slip angle (angle difference between the tire direction and the tire traveling direction) may increase as the turning angle σ increases. The cornering force F gradually decreases.

  By the way, when the vehicle turns while the steering angle of the steering wheel steered by the driver is large, the turning angle σ of the steered wheels 30 may be larger than the road surface limit steering angle σmax. In this case, there is a possibility that the cornering force F becomes small and an understeer state occurs. Accordingly, behavior support devices described in Patent Document 1, Patent Document 2, and the like have been proposed as behavior support devices for eliminating an understeer state that occurs during vehicle turning.

  When the behavior assisting device described in each of Patent Documents 1 and 2 is understeered when the vehicle turns, the turning angle σ of the steered wheels 30 is reduced to the road surface limit rudder angle σmax, and then the steered angle Steering angle adjustment control is performed to maintain σ at the road surface limit steering angle σmax. That is, the turning angle σ of the steered wheels is adjusted so that the cornering force F is maintained at the maximum value. When the cornering force F is increased by executing the turning angle adjustment control, the understeer state of the vehicle is canceled.

Japanese Patent No. 3175369 Japanese Patent No. 25659591

  By the way, when the vehicle turns, a force other than the lateral force FS based on the frictional force between the steered wheel 30 and the road surface may be applied to the steered wheel 30 of the vehicle. For example, when the road surface is a bad road or snow is accumulated, as shown in FIGS. 11 (a) and 11 (b), ridges 31 may be formed on the road surface. When the steered wheels 30 come into contact with the eaves 31 during turning of the vehicle, a resistance force FT that decelerates the vehicle from the traveling direction side acts on the side surface 30s of the steered wheels 30. Then, a cornering force (also referred to as “total cornering force”), which is a component in a direction substantially orthogonal to the traveling direction of the vehicle, of the total lateral force obtained by adding the lateral force FS and the resistance force FT acts on the vehicle. It will be. This total cornering force is larger than the cornering force F, which is a component of the lateral force FS in a direction substantially orthogonal to the traveling direction of the vehicle. Therefore, when the vehicle is turned using the lateral force FS and the resistance force FT, even if the absolute value of the turning angle σ of the steered wheels 30 is equal to or larger than the absolute value of the road surface limit steering angle σmax, the vehicle is in an understeer state. do not become.

  However, in a vehicle equipped with the conventional behavior control device, even if the driver steers the steering wheel so that the turning angle σ is larger than the road surface limit steering angle σmax, the turning angle adjustment control performs the turning angle adjustment control. σ does not become larger than the road surface limit steering angle σmax. For this reason, when the turning angle adjustment control is executed, the actual turning trajectory of the vehicle may be different from the turning trajectory desired by the driver. In particular, for the advanced driver who can turn the vehicle while adjusting the turning angle σ of the steered wheel 30 in consideration of the resistance force FT applied to the side surface 30s of the steered wheel 30, conventional behavior support is provided. A vehicle equipped with the device may give a sense of discomfort due to the fact that the vehicle cannot be turned as expected.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicle behavior support apparatus and a vehicle behavior support method that can derive the road surface limit steering angle of the steered wheels with higher accuracy. is there.

In order to achieve the above-mentioned object, the invention according to claim 1 according to the vehicle behavior support device is configured to set a limit turning angle of a steered wheel for turning the vehicle with a stable behavior, the steered wheel and a road surface. in behavior support device for the vehicle with the limit steering angle derivation means to derive on the basis of the lateral force acting on the steered wheels when the frictional force generated is maximized between, during turning of the vehicle, against the side of the steered wheels, estimated by the vertical acceleration of the resistance force applied from the traveling direction of the vehicle of the width direction of said transfer helm, it is obtained from the vibration component based on the reaction force received from the road surface a resistance force estimating means to the correction value setting means to set a correction value so as to increase the larger the resistance force which is thus estimated resistive element drag estimated hand stage, thus set in the correction value setting hand stage Therefore electrically to the limit steering angle derivation hand stage using a correction value that Is the corrected limit turning angle, the spirit and correcting hand stage, further comprising a to the correction result and the road surface limit steering angle.
According to a second aspect of the present invention relating to a vehicle behavior support device, the maximum turning angle of a steered wheel for turning the vehicle with stable behavior is set to a maximum frictional force generated between the steered wheel and the road surface. In the vehicle behavior support device provided with the limit turning angle deriving means for deriving based on the lateral force acting on the steered wheel when it becomes, the steered wheel with respect to the side surface of the steered wheel when the vehicle turns Resistance estimation means for estimating the resistance force applied from the traveling direction side of the vehicle in the width direction of the vehicle based on the amount of snow accumulated on the road surface, and the resistance force estimated by the resistance force estimation means Correcting the limit turning angle derived by the limit turning angle deriving means using the correction value setting means for setting the correction value so as to increase as the value increases, and the correction value set by the correction value setting means; The correction result is used as the road surface limit rudder angle. And summarized in that further comprising a means.
According to a third aspect of the invention relating to a vehicle behavior support device, the maximum turning angle of a steered wheel for turning the vehicle with a stable behavior is set so that the frictional force generated between the steered wheel and the road surface is maximum. In the vehicle behavior support device provided with the limit turning angle deriving means for deriving based on the lateral force acting on the steered wheel when it becomes, the steered wheel with respect to the side surface of the steered wheel when the vehicle turns A resistance force estimating means for estimating a resistance force applied from the vehicle traveling direction side in the width direction of the vehicle based on a deceleration of the vehicle when both the accelerator pedal and the brake pedal are not operated, and the resistance force The correction value setting means for setting the correction value so that the resistance force estimated by the estimation means increases and the correction value set by the correction value setting means are derived by the limit turning angle deriving means. Limit Correcting the steering angle, and summarized in that the correction result further comprises a correction means for the road surface limit steering angle, a.

  According to the above configuration, the road surface limit rudder angle is a limit steered angle derived based on the lateral force acting on the steered wheel when the frictional force generated between the steered wheel and the road surface is maximized (that is, It is derived by performing a correction process using a correction value based on the resistance force applied to the side surface of the steered wheel with respect to the conventional road surface limit steering angle). That is, the road surface limit steering angle derived by the present invention is a value close to the steering angle when the total cornering force corresponding to the sum of the lateral force and the resistance force acting on the steered wheels is maximized. Therefore, the road surface limit steering angle of the steered wheels can be derived with higher accuracy.

Therefore, when turning the vehicle, the driver of the vehicle can steer the steered wheels to the road surface limit steering angle derived by the present invention. As a result, the actual turning trajectory of the vehicle can be brought closer to the turning trajectory desired by the driver as compared with the case where the road surface limit steering angle is derived by the conventional method.
In general, when the amount of snow on the road surface on which the vehicle travels is large, there may be a large number of ridges on the road surface that can impart resistance to the side surfaces of the steered wheels. Moreover, it is considered that the size of such a kite increases as the amount of snow accumulation increases, and the resistance applied to the side surface of the steered wheel increases as the kite increases. Therefore, in the invention described in claim 2, the correction value is set to be larger as the amount of snow on the road surface when the vehicle turns is larger. Therefore, it becomes possible to make the limit turning angle approach the original limit turning angle as compared with the case where the road surface limit turning angle is derived by a conventional method.
On the other hand, generally, when the deceleration of the vehicle is large, there may be a large number of ridges on the road surface that can impart resistance to the side surfaces of the steered wheels. Moreover, it is considered that the size of such a kite increases as the deceleration of the vehicle increases, and the resistance applied to the side surface of the steered wheel increases as the kite increases. Therefore, in the invention described in claim 3, the correction value is set to be larger as the deceleration of the vehicle is larger. Therefore, it becomes possible to make the limit turning angle approach the original limit turning angle as compared with the case where the road surface limit turning angle is derived by a conventional method.

According to a fourth aspect of the present invention, in the vehicle behavior support device according to any one of the first to third aspects, an actual yaw rate and a steering angle of a steering wheel based on a detection signal from a yaw rate sensor provided in the vehicle. when the vehicle by the target yaw rate based on the further comprising a determining hands stage whether the understeer condition, the correction manual stage, said determination hand stage Therefore the vehicle is determined to be in an understeer state, by correcting the limit turning angle thus derived in the limit steering angle derivation hand stage using the correction value setting correction value set by the hand stage, greater than the absolute value of該限field turning angle The gist is to derive a road surface limit rudder angle having an absolute value.

  According to the above configuration, when the vehicle is understeered, the road surface limit rudder angle is derived based on the lateral force acting on the steered wheels when the frictional force generated between the steered wheels and the road surface is maximized. It is derived by performing a correction process using a correction value based on the resistance force applied to the side surface of the steered wheel with respect to the limit steered angle (that is, the conventional road surface limit steered angle). Therefore, the road surface limit steering angle of the steered wheels when the vehicle is in an understeer state is suitably derived.

The invention described in claim 5, in behavior support apparatus for a vehicle according to claim 4, the vehicle has an adjustable turning angle adjustment Organization the turning angle of the steered wheels, the steering a turning angle calculation means to calculating the steering angle of the wheels, during turning of the vehicle, when the the determination hand stage Therefore the vehicle is determined to be in an understeer state, depending on the turning angle calculation hand stage the absolute value of the steering angle is calculated further and a control means to control the steering angle adjustment Organization to be equal to or less than the absolute value of the road surface limit steering angle is thus led to the correction manual stage Is the gist.

  According to the above configuration, when the vehicle is understeered, the steered wheels are controlled so that the absolute value of the steered angle is equal to or less than the absolute value of the road surface limit steered angle derived by the present invention. For this reason, the cornering force applied to the vehicle is suppressed from being reduced due to the absolute value of the turning angle becoming too large. Therefore, it can contribute to the elimination of the understeer state of the vehicle. Further, when turning the vehicle, the vehicle driver can steer the steered wheels to the road surface limit rudder angle derived by the present invention. As a result, the actual turning trajectory of the vehicle can be brought closer to the turning trajectory desired by the driver as compared with the case where the road surface limit steering angle is derived by the conventional method.

On the other hand, the invention according to claim 6 according to the vehicle behavior support method generates a limit turning angle of the steered wheels for turning the vehicle with stable behavior between the steered wheels and the road surface. in behavior support method for a vehicle having a limit steering angle derivation steps for calculating on the basis of the lateral force acting on the steered wheels when the frictional force is maximized, during turning of the vehicle, on a side surface of the steering wheel in contrast, the resistance force applied from the traveling direction of the vehicle of the width direction of said transfer steering wheel, a resistance force estimation steps for estimating the vertical acceleration that is obtained from the vibration component based on the reaction force received from the road surface the limit rolling by using the correction value setting steps for setting a correction value so as to become larger as the resistance force that the hand estimated resistive element drag estimation steps is large, a correction value hand set in the correction value setting steps was hand led to the steering angle derivation steps It is corrected field turning angle, and summarized in that further comprises a correction steps for the correction result and the road surface limit steering angle, a.

According to the said structure, the effect equivalent to the invention of Claim 1 can be acquired.
The invention according to claim 7 according to the vehicle behavior support method is such that the maximum turning angle of the steered wheel for turning the vehicle with stable behavior is the maximum frictional force generated between the steered wheel and the road surface. In the vehicle behavior support method having a step of deriving a limit turning angle that is calculated based on the lateral force acting on the steered wheel when the vehicle turns, the steered wheel has a side surface of the steered wheel when the vehicle turns. The resistance force estimation step for estimating the resistance force applied from the traveling direction side of the vehicle in the width direction based on the amount of snow accumulated on the road surface, and the resistance force estimated in the resistance force estimation step is large A correction value setting step for setting the correction value so as to increase, and the correction value set in the correction value setting step is used to correct the limit turning angle derived in the limit turning angle derivation step, The correction result is the road surface limit. A correction step of a steering angle, further comprising the the gist.
According to the said structure, the effect equivalent to the invention of Claim 2 can be acquired.
In the invention according to claim 8 relating to the vehicle behavior support method, the maximum turning angle of the steered wheels for turning the vehicle with stable behavior is set to a maximum frictional force generated between the steered wheels and the road surface. In the vehicle behavior support method having a step of deriving a limit turning angle that is calculated based on the lateral force acting on the steered wheel when the vehicle turns, the steered wheel has a side surface of the steered wheel when the vehicle turns. A resistance force estimation step for estimating a resistance force applied from the vehicle traveling direction side in the width direction based on a deceleration of the vehicle when neither the accelerator pedal nor the brake pedal is operated, and the resistance force estimation In the correction value setting step for setting the correction value so as to increase as the resistance force estimated in the step increases, and in the limit turning angle derivation step using the correction value set in the correction value setting step. Is corrected limit turning angle issued, and summarized in that further comprising the correction result and a correction step of the road surface limit steering angle, a.
According to the said structure, the effect equivalent to the invention of Claim 3 can be acquired.

1 is a block diagram showing a schematic configuration of a vehicle in a first embodiment. A map for setting the friction limit steering angle from the steering angle of the steering wheel and the vehicle body speed of the vehicle. A map for setting the correction angle based on the rough road index of the road surface. The flowchart explaining the understeer elimination processing routine in 1st Embodiment. (A) The timing chart which shows the fluctuation | variation of the wheel acceleration of a wheel, (b) is a timing chart which shows the fluctuation | variation of the wheel acceleration after a filter. The timing chart which shows the relationship between the steering angle of a steering wheel, and the turning angle of a front wheel. Map for setting correction gain based on vehicle deceleration. The flowchart explaining a part of understeer elimination processing routine in 2nd Embodiment. The action figure which illustrates typically the side force and cornering force which act on a steered wheel. The graph which shows the relationship between a steering angle and a cornering force. (A) is an action figure which shows a mode that a vehicle turns typically, (b) is a mimetic diagram showing typically a mode that resistance from a rod acts on a side of a steered wheel.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In the following description of the present specification, the traveling direction (forward direction) of the vehicle is assumed to be the front (front of the vehicle). Unless otherwise specified, the left-right direction in the following description is the same as the left-right direction in the vehicle traveling direction.

  As shown in FIG. 1, the vehicle of this embodiment includes a plurality of (four in this embodiment) wheels (a right front wheel FR, a left front wheel FL, a right rear wheel RR, and a left rear wheel RL). The vehicle is provided with a driving force generator (not shown) having an engine capable of generating a driving force corresponding to the amount of depression of the accelerator pedal 11 by the driver. The driving force is transmitted from the driving force generator to at least two wheels (for example, front wheels FR, FL) among the wheels FR, FL, RR, RL, so that the vehicle travels. Further, the vehicle has a front wheel steering device 12 as a turning angle adjusting mechanism for turning the front wheels FR and FL as steered wheels (also referred to as “steering wheels”), and the driver depresses the brake pedal 13. A braking device (not shown) capable of applying a braking force corresponding to the operation amount to each of the wheels FR, FL, RR, RL is provided.

  The front wheel steering device 12 includes a steering wheel 14 that is steered by a driver, a steering shaft 15 to which the steering wheel 14 is fixed, and a steering actuator 16 that is coupled to the steering shaft 15. Further, the front wheel steering device 12 is provided with a link mechanism portion 17 including a tie rod that can be moved in the left-right direction of the vehicle by a steering actuator 16 and a link that steers the front wheels FL and FR by the movement of the tie rod. It has been. Further, the front wheel steering device 12 is provided with a steering angle sensor SE1 for detecting the steering angle of the steering wheel 14, and the steering angle sensor SE1 is an electronic control device (hereinafter, referred to as a vehicle control device) for controlling the vehicle. It is electrically connected to “ECU”) 18. The steered actuator 16 operates so that the steered angle of the front wheels FR and FL becomes an angle corresponding to the steering angle θ of the steering wheel 14 (see FIG. 2).

Next, the ECU 18 of this embodiment will be described.
The input interface of the ECU 18 includes a steering angle sensor SE1, an accelerator opening sensor SE2 for detecting the depression amount of the accelerator pedal 11 by the driver, that is, an accelerator opening, and wheels of the wheels FR, FL, RR, and RL. Wheel speed sensors SE3, SE4, SE5, and SE6 for detecting the speed are electrically connected. The input side interface also includes a longitudinal G sensor SE7 for detecting a longitudinal deceleration (hereinafter simply referred to as "deceleration"), which is a deceleration in the traveling direction of the vehicle, and a yaw rate of the vehicle. A yaw rate sensor SE8 for detection and a brake switch SW1 for detecting that the brake pedal 13 is operated are electrically connected. In the present embodiment, the steering angle sensor SE1 and the yaw rate sensor SE8 output a detection signal corresponding to a positive value when turning leftward, and output a detection signal corresponding to a negative value when turning rightward. It is like that. The front / rear G sensor SE7 outputs a detection signal corresponding to a positive value when the vehicle decelerates, and outputs a detection signal corresponding to a negative value when the vehicle accelerates.

  The driving force generator, the front wheel steering device 12 and the braking device are electrically connected to the output side interface of the ECU 18. The ECU 18 individually controls the driving force generator, the front wheel steering device 12, and the braking device based on various detection signals from the brake switch SW1 and the various sensors SE1 to SE8. Therefore, in the present embodiment, the ECU 18 functions as a behavior support device that controls each device in order to stabilize the behavior of the vehicle.

  The digital computer of the ECU 18 includes a CPU 19, a ROM 20, a RAM 21, and the like. The ROM 20 stores in advance various control processes (such as understeer elimination processing described later), various maps (such as various maps shown in FIGS. 2 and 3), various thresholds (such as rough road index thresholds described later), and the like. The RAM 21 stores various information (wheel speed, vehicle body speed, steering angle, steering angle, actual yaw rate, target yaw rate, friction limit, which will be described later) while the ignition switch (not shown) of the vehicle is “ON”. Steering angle, rough road index, correction angle, road surface limit steering angle, etc.) are stored.

Next, a map stored in advance in the ROM 20 will be described with reference to FIGS.
The map shown in FIG. 2 (hereinafter referred to as “first map”) is a map for deriving a friction limit steering angle σ_f that is a road surface limit steering angle based on the μ value (friction coefficient) of the road surface on which the vehicle travels. It is. Since it is very difficult to detect the μ value of the road surface, in the present embodiment, the friction limit steering angle σ_f is derived based on the steering angle θ of the steering wheel 14 and the vehicle body speed VS. That is, the first map is a three-dimensional map that is set in advance using the steering angle θ and the vehicle body speed VS as parameters, and the steering angle (for easily controlling the vehicle motion by steering the steering wheel 14 by the driver). That is, this is a map for setting the friction limit steering angle σ_f so as to be a cornering force. When the μ value (friction coefficient) of the road surface is low, the vehicle is in an understeer state even when the vehicle body speed VS is slow or the absolute value of the steering angle θ is small as compared to when driving on a road surface with a high μ value. Prone. This understeer image pair means that the actual turning locus of the vehicle swells outward from the turning locus intended by the driver. Therefore, the friction limit steering angle σ_f is set to a steering angle that makes it easy to control the movement of the vehicle by steering the steering wheel 14 by the driver based on the first map. For example, when the steering angle θ is the first steering angle θ1 and the vehicle body speed VS is the first vehicle body speed VS1, the friction limit steering angle σ_f is set to the first limit steering angle σ_f1. Note that the first limit steering angle σ_f1 is a point on the surface of the figure drawn three-dimensionally in FIG.

  Here, the friction limit steering angle σ_f is a road surface limit steering angle derived by a so-called conventional method. Specifically, when the vehicle turns, the front wheels FR and FL, which are steered wheels, have frictional force generated between the front wheels FR and FL (specifically, tires attached to the front wheels) and the road surface. A lateral force FS based (see FIGS. 9 and 11) is applied. The lateral force FS is a force acting in a direction substantially orthogonal to the direction of the front wheels FR and FL by the generation of the frictional force. The cornering force F (see FIGS. 9 and 10), which is a component acting in a direction substantially orthogonal to the traveling direction of the front wheels FR and FL in the lateral force FS, is applied to the vehicle, so that the vehicle turns. ing. At this time, the greater the cornering force F, the smaller the turning radius of the vehicle, that is, the vehicle tends to bend. Therefore, the turning angle σ when the cornering force applied to the vehicle based on the lateral force FS is maximized is the friction limit steering angle σ_f.

  The map shown in FIG. 3 (hereinafter referred to as “second map”) is corrected as a correction value for deriving the road surface limit steering angle σmax (see FIG. 4) that is set when the vehicle is understeered. It is a map for setting an angle Δσ. The second map shows the relationship between the rough road index Nrw numerically indicating the degree of unevenness of the road surface on which the vehicle travels and the magnitude of the correction angle Δσ. Specifically, when the rough road index Nrw is “0 (zero)”, there is almost no unevenness on the running road surface, and therefore the correction angle Δσ is set to “0 (zero)”. . Further, when the rough road index Nrw is “1”, the degree of unevenness of the running road surface is larger than that when the rough road index Nrw is “0 (zero)”. The first correction angle Δσ1 is larger than “0 (zero)”. In addition, when the rough road index Nrw is “2”, the degree of unevenness of the running road surface is larger than that when the rough road index Nrw is “1”, so the correction angle Δσ is the first correction. The second correction angle Δσ2 is larger than the angle Δσ1. When the rough road index Nrw is “3”, the degree of unevenness of the running road surface is larger than that when the rough road index Nrw is “2”. The third correction angle Δσ3 is larger than the angle Δσ2. Each of these correction angles Δσ1 to Δσ3 is an angle set according to the turning angle of the front wheels FR and FL when the advanced driver turns the vehicle on the road surface of the corresponding rough road index Nrw. The calculation method of the rough road index Nrw will be described later.

  Next, among various control processing routines executed by the ECU 18 of the present embodiment, an understeer elimination processing routine will be described based on the flowchart shown in FIG. 4 and the graphs shown in FIGS. 5 and 6.

  Now, the ECU 18 executes an understeer elimination processing routine at predetermined intervals set in advance (in this embodiment, every 10 msec. (Milliseconds)). In this understeer elimination processing routine, the ECU 18 calculates the wheel speed VW of each wheel FR, FL, RR, RL based on each detection signal from each wheel speed sensor SE3 to SE6 (step S10). Subsequently, the ECU 18 calculates the vehicle body speed VS of the vehicle using at least one wheel speed among the wheel speeds VW of the wheels FR, FL, RR, RL calculated in step S10 (step S11). Then, the ECU 18 calculates the steering angle θ of the steering wheel 14 based on the detection signal from the steering angle sensor SE1 (step S12). Subsequently, the ECU 18 calculates the turning angle σ of the front wheels FR and FL based on the steering angle θ calculated in step S12 (step S13). When the steering angle θ of the steering wheel 14 is calculated, the turning angle σ of the front wheels FR and FL becomes an angle corresponding to the steering angle θ by the operation of the turning actuator 16. That is, there is a proportional relationship between the steering angle θ and the turning angle σ. Therefore, the ECU 18 derives the turning angle σ by multiplying the steering angle θ by a preset gain (a gear ratio n of the steering wheel 14 described later). Therefore, in this embodiment, ECU18 functions as a turning angle calculation means.

  Then, the ECU 18 calculates a yaw rate (hereinafter referred to as “actual yaw rate”) Y actually acting on the vehicle based on the detection signal from the yaw rate sensor SE8 (step S14). Subsequently, the ECU 18 calculates the target yaw rate Yst by substituting the steering angle θ of the steering wheel 14 calculated in step S12 into the following relational expression (formula 1) (step S15).

ただし、Ｙｓｔ…目標ヨーレート、ＶＳ…車両の車体速度、Ａ…スタビリティファクタ、θ…操舵角、ｎ…ステアリングホイールのギヤ比、Ｌ…車両のホイールベース長
続いて、ＥＣＵ１８は、ステップＳ１４にて演算した実ヨーレートＹがステップＳ１５にて演算した目標ヨーレートＹｓｔ未満であるか否かを判定する（ステップＳ１６）。なお、実ヨーレートＹが目標ヨーレートＹｓｔ未満となる場合とは、車両の旋回状態がアンダーステア状態になったことを示す。したがって、本実施形態では、ＥＣＵ１８が、アンダーステア状態であるか否かを判定する判定手段としても機能する。

However, Yst ... target yaw rate, VS ... vehicle body speed, A ... stability factor, .theta .... steering angle, n ... steering wheel gear ratio, L ... vehicle wheelbase length Subsequently, the ECU 18 proceeds to step S14. It is determined whether or not the calculated actual yaw rate Y is less than the target yaw rate Yst calculated in step S15 (step S16). The case where the actual yaw rate Y is less than the target yaw rate Yst indicates that the turning state of the vehicle has become an understeer state. Therefore, in this embodiment, the ECU 18 also functions as a determination unit that determines whether or not the vehicle is in an understeer state.

  If the determination result in step S16 is negative (Y ≧ Yst), the ECU 18 determines that the turning state of the vehicle is not an understeer state, and temporarily ends the understeer elimination processing routine. On the other hand, if the determination result in step S16 is affirmative (Y <Yst), the ECU 18 determines that the turning state of the vehicle has become an understeer state, and uses the vehicle body speed VS and the steering angle θ calculated in steps S11 and S12. By substituting into the first map, the friction limit steering angle σ_f is derived (step S17). Therefore, in the present embodiment, the ECU 18 also functions as a limit turning angle derivation unit that derives the friction limit steering angle σ_f based on the vehicle body speed VS and the steering angle θ at the time of the understeer state. Step S17 corresponds to a limit turning angle derivation step. Subsequently, the ECU 18 calculates a current rough road index Nrw on the road surface on which the vehicle travels (step S18).

  That is, the ECU 18 differentiates the wheel speeds VW of the respective wheels FR, FL, RR, RL calculated in step S10, whereby the wheel accelerations DVW of the respective wheels FR, FL, RR, RL (FIG. 5 (a)). (B) is calculated. And ECU18 acquires the wheel acceleration DVWF after filter from which the low frequency component was removed for every wheel FR, FL, RR, and RL by performing the filtering process which takes out the high frequency component of wheel acceleration DVW.

  As shown in FIG. 5 (a), the wheel acceleration DVW of the wheels FR, FL, RR, RL before the filtering process includes the acceleration components of the original wheels FR, FL, RR, RL and the reaction force received from the road surface. The vibration component based on each is included. The vibration frequency indicating the fluctuation of the vibration component is higher than the acceleration frequency indicating the fluctuation of the acceleration component. Therefore, in the present embodiment, the filtered wheel acceleration DVWF is extracted from the wheel acceleration DVW as shown in FIG. 5B by using the filtering process, that is, a high-pass filter.

  Thereafter, when a predetermined number of filtered wheel accelerations DVWF are acquired for each of the wheels FR, FL, RR, and RL, the ECU 18 calculates a variance value of the filtered wheel accelerations DVWF for each of the wheels FR, FL, RR, and RL. . These variance values are values obtained by accumulating values obtained by squaring each filtered wheel acceleration DVWF and dividing the accumulated value by the number of samples. When the maximum value (for example, the dispersion value corresponding to the left front wheel FL) among the dispersion values for each of the wheels FR, FL, RR, and RL is less than a preset first dispersion threshold, the ECU 18 The rough road index Nrw is set to “0 (zero)”, and the second variance is set in advance such that the maximum value among the variance values is equal to or greater than the first variance threshold and greater than the first variance threshold. If it is less than the threshold, the rough road index Nrw is set to “1”. Further, the ECU 18 sets a third variance that is set in advance so that the maximum value among the variance values for each of the wheels FR, FL, RR, and RL is greater than or equal to the second variance threshold and greater than the second variance threshold. If it is less than the threshold value, the rough road index Nrw is set to “2”, and if the maximum value among the variance values is equal to or greater than the third variance threshold value, the rough road index Nrw is set to “3”. Each dispersion threshold is a value for setting the rough road index Nrw to “0 (zero)” to “3” depending on the size of the dispersion value, and is set in advance by an experiment or simulation.

  In addition, it is highly likely that a large number of large ridges 31 (see FIG. 11) are formed on the road surface on which the vehicle travels as the bad road index Nrw increases. When the eaves 31 come into contact with the front side of the front wheels FR and FL that are steered when the vehicle turns, the side surfaces of the front wheels FR and FL (more specifically, tires) have the direction of the front wheels FR and FL from the eaves 31 A resistance force FT (see FIG. 11) in a substantially orthogonal direction is applied. As a result, when the vehicle turns, the front wheels FR and FL are respectively given a lateral force FS in a direction perpendicular to the direction of the front wheels FR and FL and a resistance force FT that is a force different from the lateral force FS. Is done. The direction in which the resistance force FT acts on the side surfaces of the front wheels FR and FL is substantially the same as the direction in which the lateral force FS acts. Therefore, a cornering force (hereinafter referred to as “total cornering force”) corresponding to a total value of lateral force FS and resistance force FT (hereinafter referred to as “total lateral force”) is applied to the vehicle. Therefore, in the present embodiment, the ECU 18 determines the value of the road surface as a value corresponding to the resistance force FT applied to the side surface of the front wheels FR and FL when turning the vehicle from the traveling direction side of the vehicle. It also functions as a resistance estimation means for calculating the rough road index Nrw. Step S18 corresponds to a resistance estimation step. Note that when the vehicle travels on a road surface with a large bad road index Nrw, the deceleration becomes larger than when the vehicle travels on a road surface with a small bad road index Nrw.

  Subsequently, the ECU 18 determines whether or not the rough road index Nrw calculated in step S18 is greater than or equal to a preset rough road index threshold KNrw (for example, “1”) (step S19). The rough road index threshold value KNrw is a reference value for determining whether or not a sufficiently large resistance force FT is applied to the side surfaces of the front wheels FR and FL, and is set in advance by experiments or simulations. Is done. If the determination result in step S18 is negative (Nrw <KNrw), the ECU 18 determines that the magnitude of the resistance force FT applied to the side surfaces of the front wheels FR, FL can be ignored, and the road surface limit steering angle σmax is rubbed. The limit rudder angle σ_f is set (step S20), and then the process proceeds to step S23 described later.

  On the other hand, if the determination result in step S19 is affirmative (Nrw ≧ KNrw), the ECU 18 determines that the magnitude of the resistance force FT applied to the side surfaces of the front wheels FR and FL cannot be ignored, and calculates in step S18. The rough road index Nrw is substituted into the second map shown in FIG. 3, and a correction angle Δσ corresponding to the rough road index Nrw is set (step S21). Therefore, in this embodiment, the ECU 18 also functions as a correction value setting unit. Step S21 corresponds to a correction value setting step. Subsequently, the ECU 18 adds the correction angle Δσ set in step S21 to the friction limit steering angle σ_f derived in step S17, and sets the addition result as the road surface limit steering angle σmax (step S22). That is, the road surface limit steering angle σmax is derived by performing a correction process based on the correction angle Δσ on the friction limit steering angle σ_f. Therefore, in this embodiment, ECU18 functions also as a correction | amendment means. Step S22 corresponds to a correction step. Thereafter, the ECU 18 proceeds to the next step S23.

  In step S23, the ECU 18 executes the turning angle adjustment control based on the road surface limit steering angle σmax set in step S20 or step S22. Specifically, when the absolute value of the turning angle σ calculated in step S13 is larger than the absolute value of the road surface limit steering angle σmax, the ECU 18 determines that the turning angle σ of the front wheels FR and FL is the road surface limit steering angle σmax. The steering actuator 16 is controlled so that Of course, when the absolute value of the turning angle σ calculated in step S13 is equal to or smaller than the absolute value of the road surface limit steering angle σmax, the ECU 18 sets the turning angle σ of the front wheels FR and FL to the steering angle θ of the steering wheel 14. The steered actuator 16 is controlled so as to have an appropriate angle. Therefore, in this embodiment, ECU18 functions also as a control means. Thereafter, the ECU 18 once ends the understeer elimination processing routine.

  When the turning angle adjustment control is executed when the vehicle is understeered in this way, the absolute value of the turning angle σ of the front wheels FR and FL exceeds the absolute value of the road surface limit steering angle σmax. Adjusted to not. Unlike the conventional case, the road surface limit steering angle σmax is not only the lateral force FS based on the friction generated between the front wheels FR and FL and the road surface, but also the resistance force FT applied to the side surfaces of the front wheels FR and FL. Is set to an angle that also takes into account. Therefore, as shown in FIG. 6, the road surface limit rudder angle σmax is a larger angle than the conventional method, that is, the method of deriving the road surface rudder angle without considering the resistance force FT. As a result, the execution of the turning angle adjustment control not only eliminates the understeer state of the vehicle, but also brings the actual turning trajectory of the vehicle closer to the turning trajectory desired by the driver.

  When the understeer state of the vehicle is resolved by executing the turning angle adjustment control, the execution of the turning angle adjustment control is stopped. Thereafter, the turning angle σ of the front wheels FR and FL is set to an angle corresponding to the steering angle θ of the steering wheel 14.

Therefore, in this embodiment, the following effects can be obtained.
(1) The road surface limit steering angle σmax is derived based on the lateral force FS acting on the front wheels FR and FL when the frictional force generated between the front wheels FR and FL, which are steered wheels, and the road surface is maximized. The friction limit steering angle σ_f (that is, the road surface limit steering angle set by the conventional setting method) is derived by performing a correction process based on the resistance force FT applied to the side surfaces of the front wheels FR and FL. That is, the road surface limit steering angle σmax derived by the present embodiment is an angle at which the total cornering force corresponding to the sum of the lateral force FS and the resistance force FT acting on the front wheels FR and FL is maximized. Therefore, the road surface limit steering angle σmax of the front wheels FR and FL can be derived more accurately.

  (2) When the vehicle is understeered, the road surface limit rudder angle σmax is equal to the lateral force FS acting on the front wheels FR, FL when the frictional force generated between the front wheels FR, FL and the road surface becomes maximum. Is derived by adding a correction angle Δσ based on the resistance force FT applied to the side surfaces of the front wheels FR and FL to the friction limit steering angle σ_f derived based on the above. Therefore, the road surface limit steering angle σmax of the front wheels FR and FL when the vehicle is in an understeer state can be suitably derived.

  (3) In the present embodiment, the rough road index Nrw of the road surface is calculated as a value corresponding to the resistance force FT applied to the side surfaces of the front wheels FR and FL. The correction angle Δσ is set to be larger as the rough road index Nrw of the road surface when the vehicle turns is larger. Therefore, the road surface limit steering angle σmax can be made closer to the original limit turning angle as compared with the case where the road surface limit steering angle is derived by the conventional method.

  (4) When the vehicle is understeered, the front wheels FR and FL are controlled such that the absolute value of the turning angle σ is equal to or less than the absolute value of the road surface limit steering angle σmax. Therefore, it is possible to suppress the cornering force applied to the vehicle from being reduced due to the absolute values of the front wheels FR and FL becoming too large. Therefore, it can contribute to the elimination of the understeer state of the vehicle.

  (5) Further, when turning the vehicle, the driver of the vehicle can steer the front wheels FR and FL to the road surface limit steering angle σmax derived by the present embodiment. As a result, the actual turning trajectory of the vehicle can be brought closer to the turning trajectory desired by the driver as compared with the case where the road surface limit steering angle is derived by the conventional setting method. Therefore, it is possible to contribute to a reduction in the uncomfortable feeling that the driver of the vehicle feels when turning the vehicle.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is different from the first embodiment in a part of the method for deriving the road surface limit steering angle σmax. Therefore, in the following description, parts different from those of the first embodiment will be mainly described, and the same or corresponding member configurations as those of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Shall.

  A map shown in FIG. 7 (hereinafter referred to as “third map”) is stored in advance in the ROM of the ECU 18 of the present embodiment. The third map is a map for deriving a correction gain HG as a correction value based on the magnitude of the deceleration G of the vehicle. That is, as shown in FIG. 7, when the vehicle deceleration G is less than a preset deceleration threshold KG, the correction gain HG is set to “0 (zero)”. When the vehicle deceleration G is equal to the deceleration threshold value KG, the correction gain HG is set to “1”. When the vehicle deceleration G exceeds the deceleration threshold value KG, the correction gain HG is set to a larger value as the deceleration threshold value KG is larger.

  Next, an understeer elimination processing routine executed by the ECU 18 of the present embodiment will be described based on the flowchart shown in FIG. In the understeer elimination processing routine of this embodiment, the vehicle deceleration G is calculated as a value corresponding to the resistance force FT applied to the side surfaces of the front wheels FR and FL, and the correction according to the magnitude of the deceleration G is performed. The road surface limit steering angle σmax is derived using the gain HG. Therefore, FIG. 8 illustrates a portion of the understeer elimination processing routine that is different from the understeer elimination processing routine of the first embodiment.

  Now, the ECU 18 executes an understeer elimination processing routine at predetermined intervals set in advance. In this understeer elimination processing routine, the ECU 18 sequentially executes each processing corresponding to the above steps S10 to S16. If the determination result in step S16 is negative (Y ≧ Yst), the ECU 18 once ends the understeer elimination processing routine. On the other hand, when the determination result of step S16 is affirmative (Y <Yst), the ECU 18 executes a process corresponding to step S17. Subsequently, the ECU 18 determines whether or not both the accelerator pedal 11 and the brake pedal 13 are operated based on the detection signal from the accelerator opening sensor SE2 and the detection signal from the brake switch SW1 (step S30). When this determination result is a negative determination, the ECU 18 determines that at least one of the accelerator pedal 11 and the brake pedal 13 is operated, and the process proceeds to step S20. This is because the magnitude of the resistance force FT applied to the side surfaces of the front wheels FR and FL cannot be estimated from the deceleration G of the vehicle when at least one of the accelerator pedal 11 and the brake pedal 13 is operated. Because. On the other hand, if the determination result in step S30 is affirmative, the ECU 18 determines that both the accelerator pedal 11 and the brake pedal 13 are not operated, and based on the detection signal from the front and rear G sensor SE7, the vehicle deceleration G Is calculated (step S31).

  Here, when a large number of saddles 31 are formed on the road surface that can apply the resistance force FT to the side surfaces of the front wheels FR and FL that are steered wheels when the vehicle is turning, the vehicle is decelerated by each of the saddles 31. It is done. Moreover, the vehicle deceleration G tends to increase as the resistance force FT applied to the side surfaces of the front wheels FR and FL increases. Therefore, in this embodiment, the magnitude of the resistance force FT is estimated according to the deceleration G of the vehicle. Therefore, in the present embodiment, the ECU 18 sets the value corresponding to the resistance force FT applied from the vehicle traveling direction side in the width direction to the side surfaces of the front wheels FR and FL when the vehicle is turning. It also functions as a resistance estimation means for calculating the deceleration G. Step S31 corresponds to a resistance estimation step.

  Subsequently, the ECU 18 determines whether or not the deceleration G calculated in step S31 is equal to or greater than the deceleration threshold KG (step S32). The deceleration threshold value KG is a reference value for determining whether or not a sufficiently large resistance force FT is applied to the side surfaces of the front wheels FR and FL, and is set in advance by experiments or simulations. The If the determination result in step S32 is negative (G <KG), the ECU 18 determines that the magnitude of the resistance force FT on the side surfaces of the front wheels FR and FL can be ignored, and the process proceeds to S20. On the other hand, if the determination result in step S32 is affirmative (G ≧ KG), the ECU 18 determines that the magnitude of the resistance force FT on the side surfaces of the front wheels FR and FL cannot be ignored, and the deceleration calculated in step S31. G is substituted into the third map shown in FIG. 7, and the correction gain HG is set (step S33). Therefore, in this embodiment, step S33 corresponds to a correction value setting step.

  Subsequently, the ECU 18 multiplies the friction limit steering angle σ_f calculated in step S17 by the correction gain HG, and sets the multiplication result as a road surface limit steering angle σmax (step S34). That is, the road surface limit steering angle σmax is derived by performing a correction process based on the correction gain HG on the friction limit steering angle σ_f. Therefore, in this embodiment, step S34 corresponds to a correction step. Then, the ECU 18 shifts the process to step S23, and then ends the understeer elimination processing routine once.

Therefore, in this embodiment, in addition to the effects (1), (4), and (5) in the first embodiment, the following effects can be further obtained.
(6) When the vehicle is understeered, the road surface limit rudder angle σmax is equal to the lateral force FS acting on the front wheels FR, FL when the frictional force generated between the front wheels FR, FL and the road surface is maximized. Is derived by multiplying the friction limit steering angle σ_f derived on the basis of the correction gain HG based on the resistance force FT applied to the side surfaces of the front wheels FR and FL. Therefore, the road surface limit steering angle σmax of the front wheels FR and FL when the vehicle is in an understeer state can be suitably derived.

  (7) In the present embodiment, the deceleration G of the vehicle is calculated as a value corresponding to the resistance force FT applied to the side surfaces of the front wheels FR, FL. The correction gain HG is set so as to increase as the vehicle deceleration G during vehicle turning increases. Therefore, the road surface limit steering angle σmax can be made closer to the original limit turning angle as compared with the case where the road surface limit steering angle is derived by the conventional method.

  (8) When at least one of the accelerator pedal 11 and the brake pedal 13 is operated, the degree of deceleration of the vehicle is accurately detected based on the magnitude of the resistance force FT acting on the side surfaces of the front wheels FR and FL. Is difficult. Therefore, in such a case, the friction limit steering angle σ_f is set to the road surface limit steering angle σmax. Since the road surface limit rudder angle σmax set in this way is smaller than the actual road surface limit rudder angle, the understeer state of the vehicle can be eliminated by executing the turning angle adjustment control.

Each embodiment may be changed to another embodiment as described below.
In each embodiment, a snow cover amount detection device that detects the snow cover amount of snow accumulated on the road surface as a value corresponding to the resistance force FT is provided, and correction is performed according to the snow cover amount detected by the snow cover amount detection device. The angle Δσ and the correction gain HG may be set. In other words, as the amount of snow accumulation increases, there is a high possibility that a large number of ridges 31 that can apply the resistance force FT to the side surfaces of the front wheels FR and FL when the vehicle turns are formed on the road surface. Therefore, if the amount of snow can be detected, the resistance force FT can be estimated according to the amount of snow.

  In addition, as a method for detecting the amount of snow, a method can be considered in which an imaging unit having a CCD camera or the like is provided on the front side of the vehicle and the amount of snow is estimated from an image captured by the imaging unit. In addition, if the vehicle can receive various types of information from the outside (for example, an artificial satellite), information on the weather may be received and the amount of snow accumulation may be estimated from the reception result.

  In the second embodiment, the vehicle may be provided with a vertical G sensor for detecting acceleration in the vertical direction of the vehicle. This is because when the vehicle travels on a road surface having a large bad road index Nrw, the vehicle vibrates in the vertical direction (that is, moves up and down) by a reaction force from the road surface. That is, when the vehicle is decelerating in a state where the vertical movement of the vehicle is detected by the detection signal from the vertical G sensor, the correction gain HG corresponding to the deceleration G is detected.

  In the first embodiment, a vertical G sensor for detecting acceleration in the vertical direction of the vehicle is provided in the vehicle, and a rough road index Nrw on the road surface based on a change in vertical acceleration based on a detection signal from the vertical G sensor. May be calculated.

  In each embodiment, the friction limit rudder angle σ_f of the front wheels FR and FL when the vehicle is in an oversteer state, the steering angle θ of the steering wheel 14 when the vehicle is in an oversteer state, and the vehicle body speed VS In this case, the road surface limit steering angle σmax may be derived based on the friction limit steering angle σ_f and the correction value based on the magnitude of the resistance force FT. The oversteer state means that the actual turning locus of the vehicle turns inward from the turning locus intended by the driver.

  In the first embodiment, the correction gain HG based on the magnitude of the rough road index Nrw on the road surface is derived, and the road surface limit steering angle σmax is calculated by multiplying the friction limit steering angle σ_f by the correction gain HG. May be. In the second embodiment, the road surface limit steering angle σmax is calculated by deriving a correction angle Δσ based on the magnitude of the deceleration G of the vehicle and adding the correction angle Δσ to the friction limit steering angle σ_f. May be.

  In each embodiment, in the turning angle adjustment control in the vehicle that also turns the rear wheels RR and RL according to the steering of the steering wheel 14 during turning, not only the turning angle σ of the front wheels FR and FL is adjusted, The turning angles of the rear wheels RR and RL may also be adjusted.

  In each embodiment, the target yaw rate may be calculated using the vehicle body speed VS of the vehicle, and it may be determined whether or not the vehicle is understeered based on the target yaw rate and the actual yaw rate Y.

  DESCRIPTION OF SYMBOLS 12 ... Front wheel turning apparatus as a turning angle adjustment mechanism, 18 ... Limit turning angle derivation means, resistance force estimation means, correction value setting means, correction means, determination means, ECU as control means, FR, FL, RR , FL: Wheel as a steered wheel, FS: Lateral force, FT: Resistance, G: Deceleration, HG: Correction gain as a correction value, Nrw: Bad road index, σ: Steering angle, σ_f: Friction limit rudder Angle, σmax: Road surface limit steering angle, Δσ: Correction angle as a correction value.

Claims (8)

The lateral turning force acting on the steered wheels when the frictional force generated between the steered wheels and the road surface is maximized to determine the limit turning angle of the steered wheels for turning the vehicle with stable behavior. in behavior support device for the vehicle with the limit steering angle derivation means to derive, based on,
During turning of the vehicle, to the side of the steered wheels is obtained a resistive force applied from the traveling direction of the vehicle of the width direction of said transfer helm, from the vibration component based on the reaction force received from the road surface a resistance force estimating means to estimate the vertical acceleration,
A correction value setting means to set a correction value so as increase the resistive element drag estimated hand stage thus resistance to be estimated is large,
Correcting hand stage using a correction value that is set by the said correction value setting hand stage corrects the limit turning angle that is thus derived to the limit steering angle derivation hand stage, to the correction result and the road surface limit steering angle And a vehicle behavior support device. The lateral turning force acting on the steered wheels when the frictional force generated between the steered wheels and the road surface is maximized to determine the limit turning angle of the steered wheels for turning the vehicle with stable behavior. in behavior support device for the vehicle with the limit steering angle derivation means to derive, based on,
During turning of the vehicle, estimated with respect to the side surface of the steering wheel, the resistance force applied from the traveling direction of the vehicle of the width direction of said transfer helm, based on the snowfall snow accumulated on the road surface and the resistance force estimation means to,
A correction value setting means to set a correction value so as increase the resistive element drag estimated hand stage thus resistance to be estimated is large,
Correcting hand stage using a correction value that is set by the said correction value setting hand stage corrects the limit turning angle that is thus derived to the limit steering angle derivation hand stage, to the correction result and the road surface limit steering angle And a vehicle behavior support device. The lateral turning force acting on the steered wheels when the frictional force generated between the steered wheels and the road surface is maximized to determine the limit turning angle of the steered wheels for turning the vehicle with stable behavior. in behavior support device for the vehicle with the limit steering angle derivation means to derive, based on,
During turning of the vehicle, to the side of the steering wheel, the resistance force applied from the traveling direction of the vehicle of the width direction of said transfer helm, in a state where the accelerator pedal and the brake pedal is not being both operated a resistance force estimating means to estimate based of the deceleration of the vehicle,
A correction value setting means to set a correction value so as increase the resistive element drag estimated hand stage thus resistance to be estimated is large,
Correcting hand stage using a correction value that is set by the said correction value setting hand stage corrects the limit turning angle that is thus derived to the limit steering angle derivation hand stage, to the correction result and the road surface limit steering angle And a vehicle behavior support device. Further comprising a yaw rate and a determination hand stage vehicle by the target yaw rate based on the steering angle whether the understeer state of the steering wheel based on the detection signal from the yaw rate sensor provided in the vehicle,
The correction Hand stage, when the determination hand stage Therefore the vehicle is determined to be in an understeer state, the limit steering angle derivation hand stage using the correction value setting correction values in hand stepped Therefore set Therefore, the road surface limit steering angle having an absolute value larger than the absolute value of the limit turning angle is derived by correcting the limit turning angle derived therefrom. The vehicle behavior support apparatus according to the item. With a vehicle has an adjustable turning angle adjustment Organization the turning angle of the steered wheels,
A turning angle calculation means to calculating the steering angle of the steered wheels,
During turning of the vehicle, when said determination hand stage Therefore the vehicle is determined to be in an understeer state, the absolute value of the corrected hand stage of the turning angle calculation hand stages thus calculated is steered angle thus behavior support apparatus for a vehicle according to claim 4, and a control means to control the steering angle adjustment Organization to be equal to or less than the absolute value of the road surface limit steering angle derived, further comprising a. The lateral turning force acting on the steered wheels when the frictional force generated between the steered wheels and the road surface is maximized to determine the limit turning angle of the steered wheels for turning the vehicle with stable behavior. in behavior support method for a vehicle having a limit steering angle derivation steps for calculating on the basis of,
During turning of the vehicle, to the side of the steered wheels is obtained a resistive force applied from the traveling direction of the vehicle of the width direction of said transfer helm, from the vibration component based on the reaction force received from the road surface a resistance force estimation steps for estimating the vertical acceleration,
A correction value setting steps for setting a correction value so as to increase as the hand estimated resistance is large resistive element drag estimation steps,
Is corrected limit turning angle that hand led to the limit steering angle derivation steps using the correction value hand set in the correction value setting steps, the correction steps for the correction result and the road surface limit steering angle, The vehicle behavior support method further comprising: The lateral turning force acting on the steered wheels when the frictional force generated between the steered wheels and the road surface is maximized to determine the limit turning angle of the steered wheels for turning the vehicle with stable behavior. in behavior support method for a vehicle having a limit steering angle derivation steps for calculating on the basis of,
During turning of the vehicle, estimated with respect to the side surface of the steering wheel, the resistance force applied from the traveling direction of the vehicle of the width direction of said transfer helm, based on the snowfall snow accumulated on the road surface and the resistance force estimation steps to be,
A correction value setting steps for setting a correction value so as to increase as the hand estimated resistance is large resistive element drag estimation steps,
Is corrected limit turning angle that hand led to the limit steering angle derivation steps using the correction value hand set in the correction value setting steps, the correction steps for the correction result and the road surface limit steering angle, The vehicle behavior support method further comprising: The lateral turning force acting on the steered wheels when the frictional force generated between the steered wheels and the road surface is maximized to determine the limit turning angle of the steered wheels for turning the vehicle with stable behavior. in behavior support method for a vehicle having a limit steering angle derivation steps for calculating on the basis of,
During turning of the vehicle, to the side of the steering wheel, the resistance force applied from the traveling direction of the vehicle of the width direction of said transfer helm, in a state where the accelerator pedal and the brake pedal is not being both operated a resistance force estimation steps for estimated based of the deceleration of the vehicle,
A correction value setting steps for setting a correction value so as to increase as the hand estimated resistance is large resistive element drag estimation steps,
Is corrected limit turning angle that hand led to the limit steering angle derivation steps using the correction value hand set in the correction value setting steps, the correction steps for the correction result and the road surface limit steering angle, The vehicle behavior support method further comprising:

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