JP2014034290A - Vehicle behavior control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out vehicle behavior control which suppresses uncomfortable feeling for a driver.SOLUTION: An electronic control device 1 includes a vehicle behavior control part which controls an actual turn behavior amount of a vehicle body to a target turn behavior amount by applying braking torque to a wheel to be controlled, and an operation threshold correction part which corrects an operation start threshold for determining operation start of vehicle behavior control based on a relative distance between a seating position of a driver and a position of a center of gravity of a vehicle. Thereby, the vehicle behavior control is executed in an operation start timing in response to the relative distance between the seating position of the driver and the position of the center of gravity of the vehicle to suppress uncomfortable feeling for the driver.

Description

  The present invention relates to a vehicle behavior control device that controls the behavior of a vehicle during a steering operation to improve running stability.

  Conventionally, a vehicle behavior control device has been known as a technique when it is determined that the yaw moment of a vehicle body accompanying a steering operation is excessive. The vehicle behavior control device obtains a target yaw moment (target yaw rate) in the reverse direction that can reduce an excessive yaw moment (yaw rate), and uses the braking force applied to the wheel to be controlled to obtain the target yaw moment (target yaw rate). By making it act on, driving stability is improved. This type of vehicle behavior control device is disclosed in Patent Documents 1 and 2 below.

  The vehicle behavior control device of Patent Document 1 controls the yaw motion of the vehicle so that the actual yaw rate matches the target yaw rate calculated based on the vehicle speed, the steering angle, and the vehicle stability factor. This vehicle behavior control device learns the stability factor for calculating the target yaw rate from the calculated stability factor calculated based on the vehicle speed, the steering angle, and the actual yaw rate. Even if is changed, the change is reflected in the stability factor to achieve stable yaw motion control.

  The vehicle behavior control device of Patent Document 2 calculates a vehicle body side slip angular velocity and a vehicle body side slip angle based on a vehicle speed, a vehicle lateral acceleration, and a yaw rate, and performs vehicle motion control (vehicles) based on the vehicle body side slip angular velocity and the vehicle body side slip angle. Set start criteria for behavior control. The start reference is changed according to changes in the position of the center of gravity of the vehicle. In vehicle motion control, control is performed based on the deviation between the target slip ratio and the actual slip ratio and the deviation between the estimated vehicle body acceleration at the vehicle center of gravity and the wheel acceleration of the wheel to be controlled.

Japanese Patent Laid-Open No. 10-258720 JP 2000-135974 A

  By the way, the change in the position of the center of gravity of the vehicle affects the way the driver feels about the vehicle behavior. However, in the conventional vehicle behavior control device, the control is performed in consideration of the change in the position of the center of gravity of the vehicle as described above. However, since the way of feeling the vehicle behavior of the driver is not considered, the control is performed. May cause the driver to feel uncomfortable.

  Therefore, an object of the present invention is to provide a vehicle behavior control device that can improve the disadvantages of the conventional example and can perform vehicle behavior control with reduced discomfort for the driver.

  In order to achieve the above object, the present invention provides a vehicle behavior control unit that controls the actual turning behavior amount of a vehicle body to a target turning behavior amount by applying a braking torque to a wheel to be controlled, a driver's seating position, and a vehicle center of gravity. And an operation threshold value correction unit that corrects an operation start threshold value for determining the operation start of the vehicle behavior control based on the relative distance to the position.

  Here, it is preferable that the operation threshold correction unit further corrects the operation start threshold based on a vehicle speed.

  In addition, it is desirable to provide a target value calculation unit that corrects the target turning behavior amount according to a deviation before and after the correction of the operation start threshold.

  Further, the target value calculation unit may reduce a deviation between the actual turning behavior amount and the target turning behavior amount when the operation start timing of the vehicle behavior control is advanced in accordance with the correction of the operation start threshold. desirable.

  In addition, it is preferable to provide a relative distance calculation unit that calculates a relative distance between the seating position and the vehicle gravity center position when at least one of the seating position of the driver and the vehicle gravity center position changes.

  According to the vehicle behavior control device of the present invention, an operation start threshold value corresponding to the relative distance between the driver's seating position and the vehicle center of gravity position is obtained, so that the operation start according to the vehicle behavior perceived by the driver is obtained. Vehicle behavior control can be started at the time. That is, this vehicle behavior control device can correct the deviation from the operation start timing of the vehicle behavior control desired by the driver. Accordingly, this vehicle behavior control device can make it difficult for the driver to feel the start delay or early start of the vehicle behavior control, so that the driver by the intervention or non-intervention of the vehicle behavior control at the deviated operation start timing. Can reduce the sense of incongruity.

FIG. 1 is a diagram illustrating an example of a vehicle to which a vehicle behavior control device according to the present invention is applied. FIG. 2 is a diagram illustrating the relationship between the vehicle speed and the vehicle behavior felt by the driver. FIG. 3 is a diagram for explaining the lateral acceleration and the like felt by the driver. FIG. 4 is a diagram for explaining the vehicle speed variable gain. FIG. 5 is a time chart for explaining the operation when the operation start threshold is corrected. FIG. 6 is a diagram for explaining the deviation before and after threshold correction. FIG. 7 is a diagram illustrating the control gain. FIG. 8 is a flowchart for explaining the operation of the vehicle behavior control apparatus according to the present invention.

  Embodiments of a vehicle behavior control apparatus according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the embodiments.

[Example]
An embodiment of a vehicle behavior control apparatus according to the present invention will be described with reference to FIGS.

  The vehicle behavior control device of this embodiment is prepared as a function of the electronic control unit (ECU) 1 shown in FIG.

  First, an example of a vehicle 10 to which this vehicle behavior control device is applied is shown in FIG.

The vehicle 10 is provided with a power source 20 such as an engine or a rotating electric machine. The vehicle 10 travels by transmitting the power of the power source 20 to the driving wheels as a driving force. The vehicle 10 is provided with a braking device that stops or decelerates the traveling vehicle 10. The braking device is configured to generate a target braking torque (target braking force) with an individual magnitude for each of the wheels W _FL , W _FR , W _RL , W _RR . Here, an example in which a frictional force is generated between the engagement elements by using the force of the brake fluid pressure, and thereby the target braking torque is generated in the wheels _WFL , _WFR , _WRL , and _WRR will be exemplified.

The braking device includes a braking unit 31 that applies a braking torque to the wheels W _FL , W _FR , W _RL , W _RR with the hydraulic pressure of the brake fluid, and supplies the hydraulic pressure supplied to the braking unit 31 to the wheels W _FL , W _FR , And a hydraulic control unit 32 as a hydraulic actuator that can be controlled for each of W _RL and W _RR . The hydraulic control unit 32 can also output the master cylinder pressure according to the operation amount of the brake pedal 35 as it is, and can increase or decrease the master cylinder pressure in accordance with a command from the electronic control unit 1. Is possible. That is, the target braking torque to be generated for each wheel W _FL , W _FR , W _RL , W _RR is calculated according to the operation amount of the brake pedal 35 of the driver, and determined by the calculation of the electronic control unit 1. There are things. The operation amount of the brake pedal 35 is detected by a brake operation amount detection device 41 such as a pedal opening sensor and transmitted to the electronic control device 1.

  In addition to the brake operation amount detection device 41, the vehicle 10 is provided with various vehicle operation information detection devices such as a steering angle sensor 42. The steering angle sensor 42 is a sensor that detects an actual steering angle (hereinafter referred to as “actual steering angle”) θ of the steering wheel 51.

Further, the vehicle 10 is provided with various vehicle travel information detection devices such as a vehicle speed sensor 43, a wheel speed sensor 44, a yaw rate sensor 45, a longitudinal acceleration sensor 46, and a lateral acceleration sensor 47. The vehicle speed sensor 43 is, for example, a sensor that detects a rotation angle of an output shaft of a transmission (not shown). The wheel speed sensor 44 is prepared for each of the wheels W _FL , W _FR , W _RL , W _RR and detects the wheel speed of the target wheel. The electronic control unit 1 estimates the vehicle speed Vx based on the rotation angle of the output shaft and the wheel speed. The yaw rate sensor 45 is a sensor that detects an actual yaw rate (hereinafter referred to as “actual yaw rate”) Yr centered on the position of the center of gravity of the vehicle. The longitudinal acceleration sensor 46 is a sensor that detects an actual longitudinal acceleration (hereinafter referred to as “actual longitudinal acceleration”) Gx that acts in the longitudinal direction of the vehicle at the position of the center of gravity of the vehicle. The lateral acceleration sensor 47 is a sensor that detects an actual lateral acceleration (hereinafter referred to as “actual lateral acceleration”) Gy that works in the vehicle lateral direction at the vehicle center of gravity.

  The vehicle behavior control device performs stabilization control of the vehicle behavior when the driver steers the steering wheel 51. The stabilization control is so-called vehicle stability control. The vehicle 10 may exhibit a neutral steer tendency or an oversteer tendency or an understeer tendency during a turning motion associated with a driver's steering operation. The vehicle behavior control device determines a target turning state according to the tendency of the vehicle behavior, that is, the actual turning state of the vehicle body (hereinafter referred to as “actual turning state”), and is controlled so as to be in this target turning state. Control the braking torque of the wheels.

The actual turning state can be determined based on the actual turning behavior amount (hereinafter referred to as “actual turning behavior amount”). The actual turning behavior amount is, for example, the actual yaw rate Yr, the actual yaw moment of the vehicle 10 calculated based on the actual yaw rate Yr (hereinafter referred to as “actual yaw moment”) My, and the like. Further, the target turning state is a state where the vehicle is turning at a target turning behavior amount (target yaw rate Yr _tgt or target yaw moment My _tgt ), for example, a state showing a neutral steer tendency or a weak understeer tendency.

In this vehicle behavior control, for example, based on the difference between the target yaw rate Yr _tgt and the actual yaw rate Yr (hereinafter referred to as “yaw rate deviation”) ΔYr (ΔYr = Yr _tgt −Yr), the target yaw rate Yr _tgt is Control is performed to match the yaw rate Yr. In this case, the target value calculation unit of the electronic control device 1 calculates the yaw rate deviation ΔYr as a target vehicle behavior control amount in the vehicle behavior control. In this vehicle behavior control, the target yaw moment My _tgt and the actual yaw moment My (hereinafter referred to as “yaw moment deviation”) ΔMy (ΔMy = My _tgt −My) Control may be performed so that the actual yaw moment My coincides with My _tgt . In this case, the yaw moment deviation ΔMy becomes the target vehicle behavior control amount in the vehicle behavior control.

When the actual turning state of the vehicle body shows an oversteer tendency, the vehicle behavior control device shows the oversteer tendency by applying a braking torque corresponding to the target vehicle behavior control amount to one or both of the front and rear turning outer wheels. A target yaw rate Yr _tgt (target yaw moment My _tgt ) opposite to the actual yaw rate Yr (actual yaw moment My) is generated in the vehicle body. Thereby, the vehicle 10 can suppress the oversteer tendency and can perform a turning operation with stable vehicle behavior.

Further, when the actual turning state of the vehicle body shows an understeering tendency, the vehicle behavior control device shows the understeering tendency by applying a braking torque corresponding to the target vehicle behavior control amount to one or both of the turning inner wheels. A target yaw rate Yr _tgt (target yaw moment My _tgt ) opposite to the actual yaw rate Yr (actual yaw moment My) is generated in the vehicle body. Thereby, the vehicle 10 can perform the turning operation in which the understeer tendency is suppressed and the vehicle behavior is stable.

  By the way, the driver can easily sense the vehicle behavior in the yaw direction based on the change in the actual yaw rate Yr when the vehicle speed is lower than a certain boundary vehicle speed V0, and the actual lateral acceleration at a higher speed than that. There is a tendency to easily sense the vehicle behavior in the lateral direction based on the change in Gy (FIG. 2). This is because, as shown in FIG. 2, the vehicle behavior due to the actual yaw rate Yr is larger than the vehicle behavior due to the actual lateral acceleration Gy in the low speed range, and the vehicle behavior due to the actual lateral acceleration Gy is greater in the high speed range. This is because the vehicle behavior is greater than the actual yaw rate Yr. As described above, the sensitivity of the vehicle behavior by the driver varies depending on the vehicle speed. Therefore, in the vehicle behavior control, the driver feels uncomfortable by controlling the yaw rate deviation ΔYr and the yaw moment deviation ΔMy as the target vehicle behavior control amount. There is a possibility to give. FIG. 2 shows an example of the sensitivity of the vehicle behavior of the driver according to the vehicle speed Vx.

Further, since there is a distance L (hereinafter referred to as “relative distance”) L between the seating position of the driver and the vehicle center of gravity position, the lateral acceleration Gy _driver sensed by the _driver is the actual lateral position at the vehicle center of gravity position. There is a deviation from the acceleration Gy by the lateral acceleration corresponding to the relative distance L and the actual yaw rate Yr centered on the vehicle center of gravity. As shown in FIG. 3, a vehicle lateral speed Vy according to the relative distance L and the actual yaw rate Yr acts on the seating position of the driver (Equation 1 below). Therefore, the lateral acceleration dVy / dt corresponding to the differential value of the velocity Vy acts on this seating position. For this reason, the lateral acceleration Gy _driver sensed by the _driver at the seating position is an addition value of the lateral acceleration dVy / dt and the actual lateral acceleration Gy (Formula 2 below). Further, the yaw rate converted by dividing the lateral acceleration Gy _driver by the vehicle speed Vx can be referred to as a yaw rate Yr _driver sensed by the _driver at the seating position (Formula 3 below). The relative distance L in this example refers to the distance between the driver's seat and the vehicle center of gravity in the vehicle longitudinal direction. The actual lateral acceleration Gy is positive in the vehicle right direction. The actual yaw rate Yr is positive in the clockwise direction.

Vy = Yr * L (1)
Gy _driver = Gy + dVy / dt (2)
Yr _driver = Gy _driver / Vx = (Gy + dVy / dt) / Vx (3)

  For example, since the driver is more sensitive to lateral acceleration in the high speed range as described above, the yaw rate deviation ΔYr does not exceed the vehicle behavior control operation start threshold ThOS (ThUS) (that is, the vehicle behavior control Although it is not the operation start time, there is a possibility that the vehicle behavior control may be misrecognized as an intervention time and the vehicle behavior control may be delayed. The operation start threshold ThOS is a value when the actual turning state of the vehicle body shows an oversteer tendency. The operation start threshold ThUS is a value when the actual turning state of the vehicle body shows an understeer tendency. Further, as described above, the driver is more sensitive to the yaw rate in the low speed range, but the driver's seating position is away from the vehicle center of gravity, so the yaw rate is difficult to detect, and the yaw rate deviation ΔYr starts the operation of the vehicle behavior control. Despite exceeding the threshold value ThOS (ThUS) (that is, although the vehicle behavior control operation start timing is reached), the vehicle behavior control operation start timing is misrecognized as an early operation, and the user feels uncomfortable. there is a possibility. That is, the turning state of the vehicle body recognized by the driver does not necessarily match the actual turning state due to the presence of the relative distance L. For example, if the actual turning state of the vehicle body shows an oversteering tendency or an understeering tendency, the driver feels that there is a neutral steering tendency, or the actual turning state shows a neutral steering tendency. You may feel oversteering or understeering. Therefore, the driver may feel uncomfortable with the intervention and non-intervention of the vehicle behavior control.

  Therefore, the vehicle behavior control apparatus according to the present embodiment is configured to perform vehicle behavior control that suppresses such a driver's uncomfortable feeling.

  In this vehicle behavior control device, the vehicle behavior control activation start threshold ThOS (ThUS) is corrected to change the vehicle behavior control activation start timing to one that suppresses the driver's uncomfortable feeling. Therefore, the electronic control device 1 is provided with an operation threshold value correction unit that corrects the operation start threshold value ThOS (ThUS).

The operation threshold correction unit uses the yaw rate Yr _driver sensed by the _driver at the sitting position as a correction amount of the operation start threshold ThOS (ThUS), and adds the yaw rate Yr _driver to the operation start threshold ThOS (ThUS). Then, the corrected operation start threshold ThOS _driver (ThUS _driver ) is determined. Therefore, the activation threshold correction unit performs calculation of the lateral acceleration _{Gy driver} described above for the driver to sense at the seating position, the yaw rate _{Yr driver} to driver based on the lateral acceleration _{Gy driver} senses at the seating position Ask for. The corrected operation start threshold ThOS _driver shown in the following formula 4 is obtained when the actual turning state of the vehicle body shows an oversteer tendency. The corrected operation start threshold ThUS _driver shown in the following formula 5 is obtained when the actual turning state of the vehicle body shows an understeer tendency. The corrected operation start thresholds ThOS _driver and ThUS _driver may be calculated only according to the actual turning state of the vehicle body, or both may be calculated regardless of the actual turning state of the vehicle body.

ThOS _driver = ThOS + Yr _driver (4)
ThUS _driver = ThUS + Yr _driver (5)

When the actual turning state of the vehicle body shows an oversteer tendency, the vehicle behavior control unit of the electronic control device 1 compares the corrected operation start threshold ThOS _driver with the yaw rate deviation ΔYr, and the actual turning state shows an understeer tendency. In the case shown, the corrected operation start threshold value ThUS _driver is compared with the yaw rate deviation ΔYr. When the yaw rate deviation ΔYr does not exceed the corrected operation start threshold ThOS _driver (ThUS _driver ), the vehicle behavior control unit does not execute the vehicle behavior control. On the other hand, if the yaw rate deviation ΔYr exceeds the corrected operation start threshold ThOS _driver , the vehicle behavior control unit executes vehicle behavior control so as to suppress the oversteer tendency, and the yaw rate deviation ΔYr is corrected after the correction start threshold. If it exceeds ThUS _driver , vehicle behavior control is executed so as to suppress the understeer tendency.

  Thus, the vehicle behavior control device corrects the vehicle behavior control operation start threshold ThOS (ThUS) in accordance with the relative distance L between the driver's seating position and the vehicle center of gravity, so that the driver feels. The vehicle behavior control can be started at the operation start time that matches the vehicle behavior. That is, this vehicle behavior control device can correct the deviation from the operation start timing of the vehicle behavior control desired by the driver. Accordingly, this vehicle behavior control device can make it difficult for the driver to feel the start delay or early start of the vehicle behavior control, so that the driver by the intervention or non-intervention of the vehicle behavior control at the deviated operation start timing. Can reduce the sense of incongruity.

[Modification 1]
Here, as described above, the sensitivity of the vehicle behavior of the driver differs depending on the vehicle speed Vx. Therefore, the operation threshold correction unit of this modification intervenes vehicle behavior control that matches the sensitivity of the vehicle behavior of the driver by changing the correction amount of the operation start threshold ThOS (ThUS) according to the vehicle speed Vx. Let

In this example, the correction amount of the operation start threshold value ThOS (ThUS) is determined by multiplying the yaw rate Yr _driver detected by the _driver at the sitting position by a predetermined vehicle speed variable gain K _Vx OS (K _Vx US). . Equation 6 below is an arithmetic expression of the corrected operation start threshold ThOS _driver when the actual turning state of the vehicle body shows an oversteer tendency, and the correction amount (K _Vx OS * Yr _driver when the oversteer tendency occurs). ) Is added to the operation start threshold ThOS. Expression 7 below is an arithmetic expression of the corrected operation start threshold ThUS _driver when the actual turning state of the vehicle body shows an understeer tendency, and the correction amount (K _Vx US * Yr _driver ) at the time of the understeer tendency. This is added to the operation start threshold ThUS. The corrected operation start thresholds ThOS _driver and ThUS _driver may be calculated only according to the actual turning state of the vehicle body, or both may be calculated regardless of the actual turning state of the vehicle body.

ThOS _driver = ThOS + K _Vx OS * Yr _driver (6)
ThUS _driver = ThUS + K _Vx US * Yr _driver (7)

FIG. 4 shows an example of vehicle speed variable gains K _Vx OS and K _Vx US. The vehicle speed variable gains K _Vx OS and K _Vx US are numerical values of −1 or more and 1 or less (−1 ≦ K _Vx OS ≦ 1, −1 ≦ K _Vx US ≦ 1). The vehicle speed variable gains K _Vx OS and K _Vx US are, for example, the above-described boundary vehicle speed V0 (the sensitivity (sensitivity) of the vehicle behavior in the yaw direction during the turning operation by the driver and the sensitivity (sensitivity) of the vehicle behavior in the lateral direction). It is “0” in the case of a changing vehicle speed). That is, when the vehicle 10 is traveling at the boundary vehicle speed V0, it is determined whether or not the vehicle behavior control needs to be executed without correcting the operation start threshold ThOS (ThUS).

The vehicle speed variable gain K _Vx OS at the time of oversteering gradually increases to “−1” until reaching a predetermined vehicle speed Vlow (<V0) with a predetermined linear function (predetermined proportional coefficient) in a region lower than the boundary vehicle speed V0. To "-1" in the lower speed range than the vehicle speed Vlow. On the other hand, this vehicle speed variable gain K _Vx OS gradually increases to “1” in a region higher than the boundary vehicle speed V0 until it reaches a predetermined vehicle speed Vhigh (> V0) with a predetermined quadratic function (quadratic curve). The vehicle speed is increased to “1” in a higher speed range than the vehicle speed Vhigh. Further, the vehicle speed variable gain K _Vx US at the time of the understeer tendency gradually increases to “1” until reaching a predetermined vehicle speed Vlow (<V0) with a predetermined linear function (predetermined proportional coefficient) in a region lower than the boundary vehicle speed V0. To “1” in a lower speed range than the vehicle speed Vlow. On the other hand, the vehicle speed variable gain K _Vx US gradually increases to “−1” until reaching a predetermined vehicle speed Vhigh (> V0) with a predetermined quadratic function (quadratic curve) in a region higher than the boundary vehicle speed V0. And is set to “−1” in the high speed range from the vehicle speed Vhigh. In this example, the vehicle speed variable gains K _Vx OS and K _Vx US are changed by the same linear function and quadratic function regardless of whether the vehicle is oversteering or understeering. The vehicle speed Vlow means a vehicle speed that is equal to or higher than the lower limit vehicle speed at which the vehicle behavior control is started and lower than the boundary vehicle speed V0. Therefore, the vehicle speed Vlow may be determined as appropriate for each vehicle (vehicle type) within the range. The lower limit vehicle speed may be set to a different vehicle speed for each vehicle (vehicle type). On the other hand, the vehicle speed Vhigh refers to a vehicle speed that is higher than the boundary vehicle speed V0 and has a vehicle body slip angle of 0 or substantially 0.

The operation threshold value correction unit calculates the yaw rate Yr _driver sensed by the _driver at the seating position as described above, and the corrected operation start threshold value ThOS based on the yaw rate Yr _driver , the actual turning state of the vehicle body, and the vehicle speed Vx. Determine the _driver (ThUS _driver ). The vehicle behavior control unit compares the corrected operation start threshold ThOS _driver (ThUS _driver ) with the yaw rate deviation ΔYr according to the actual turning state of the vehicle body, and determines whether or not the vehicle behavior control is to be executed. FIG. 5 shows an example of the necessity determination.

In FIG. 5, the vertical axis represents the yaw rate deviation ΔYr, and the horizontal axis represents time. The thick line (solid line) in FIG. 5 represents the change in the yaw rate deviation ΔYr. Since this example yaw rate deviation ΔYr is defined as “ΔYr = Yr _tgt −Yr”, a positive value indicates that the actual turning state of the vehicle body tends to be understeered, and a negative value may be used. This means that the actual turning state of the vehicle body tends to oversteer. Therefore, the broken line in the positive region in FIG. 5 indicates the operation start threshold value ThUS before correction at the time of the understeer tendency, and the broken line in the negative region indicates the operation start threshold value ThOS before the correction at the time of the oversteer tendency. Here, the operation start threshold ThOS (ThUS) before the correction is set to a constant value.

When the change in vehicle behavior is viewed from the left side of FIG. 5 based on the yaw rate deviation ΔYr, the vehicle 10 has a gradually increasing yaw rate deviation ΔYr (> 0), and an understeering tendency becomes stronger. . In this example, before the absolute value of the yaw rate deviation ΔYr exceeds the absolute value of the operation start threshold value ThUS before correction, it is assumed that the driver feels the necessity of performing vehicle behavior control that weakens the understeer tendency. In this case, the driver may feel uncomfortable that the vehicle behavior control does not intervene. However, the illustrated operation threshold value correcting unit corrects the operation start threshold value ThUS before the correction to obtain a corrected operation start threshold value ThUS _driver (absolute value) smaller than the absolute value of the operation start threshold value ThUS. Yes. Therefore, in this case, since the operation start timing of the vehicle behavior control is advanced, the vehicle behavior control unit can advance the vehicle behavior control earlier than the case where the correction of the operation start threshold ThUS is not performed. it can. Therefore, since this vehicle behavior control part can weaken the understeer tendency which the driver is feeling at an early stage, it is possible to suppress the driver's uncomfortable feeling that the vehicle behavior control is delayed.

In the vehicle 10, the yaw rate deviation ΔYr is reduced by the early behavior control of the vehicle, and the oversteer tendency is increased through the neutral steer state. In this example, when the absolute value of the yaw rate deviation ΔYr exceeds the absolute value of the operation start threshold value ThOS before correction, the driver still does not feel the necessity of performing vehicle behavior control that weakens the oversteer tendency And In this case, the driver may feel uncomfortable with the vehicle behavior control intervention that tries to weaken the oversteer tendency. However, the illustrated operation threshold value correcting unit corrects the operation start threshold value ThOS before the correction, and obtains a corrected operation start threshold value ThOS _driver (absolute value) larger than the absolute value of the operation start threshold value ThOS. Yes. Therefore, in this case, since the operation start timing of the vehicle behavior control is delayed, the vehicle behavior control unit can delay the intervention of the vehicle behavior control compared to the case where the correction of the operation start threshold ThOS is not performed. . Therefore, the vehicle behavior control unit can suppress the driver's uncomfortable feeling that the vehicle behavior control intervention is not felt necessary.

  As described above, the vehicle behavior control apparatus according to this modified example corrects the operation start threshold ThOS (ThUS) for vehicle behavior control according to the driver's seating position and the vehicle center of gravity position, as in the embodiment. Thus, the vehicle behavior control according to the change in the vehicle behavior can be executed without causing the driver to feel the start delay or early start of the vehicle behavior control. Further, since the vehicle behavior control device of this modified example corrects the operation start threshold ThOS (ThUS) in accordance with the vehicle speed Vx, it is not necessary to intervene in the vehicle behavior control that the driver feels in the lower speed range than the boundary vehicle speed V0. It is possible to suppress the feeling and the feeling of delay in the operation of the vehicle behavior control that the driver feels at a higher speed than the boundary vehicle speed V0.

[Modification 2]
The vehicle behavior control device of the embodiment and the modification 1 described above changes the operation start timing of the vehicle behavior control. For this reason, for example, when the vehicle behavior control is started early and operated early, the driver's discomfort with respect to the vehicle behavior is suppressed, while the vehicle 10 side requires intervention of the vehicle behavior control. Therefore, unnecessary deceleration is applied to the vehicle 10.

Therefore, the vehicle behavior control apparatus according to this modified example has a target so that the unnecessary vehicle deceleration can be kept small when there is a possibility of generating unnecessary vehicle deceleration by advancing the operation start timing of the vehicle behavior control. The vehicle behavior control amount (yaw rate deviation ΔYr or yaw moment deviation ΔMy) is corrected to a small value. For example, in this example, the target vehicle behavior control amount (yaw rate deviation ΔYr or yaw moment deviation ΔMy) is corrected by correcting the target turning behavior amount (target yaw rate Yr _tgt or target yaw moment My _tgt ) in the vehicle behavior control. I do.

Specifically, when the actual turning state of the vehicle body shows an oversteer tendency, the target value calculation unit indicates a deviation between the operation start threshold value ThOS before correction and the operation start threshold value ThOS _driver after correction (hereinafter referred to as “threshold correction”). When the absolute value of ΔThOS is calculated and the actual turning state shows an understeer tendency, the deviation between the operation start threshold value ThUS before correction and the operation start threshold value ThUS _driver after correction (threshold correction). The absolute value of front-rear deviation) ΔThUS is calculated. The calculation of the threshold correction front-rear deviation ΔThOS (ΔThUS) is performed between the pre-correction operation start threshold ThOS and the post-correction operation start threshold ThOS _driver , or the pre-correction operation start threshold ThUS and the post-correction operation start threshold ThUS. _This may be performed when the yaw rate deviation ΔYr exists with respect to the _driver and when the operation start timing of the vehicle behavior control is advanced. FIG. 6 shows the threshold correction before and after deviation ΔThUS when the operation start timing of the vehicle behavior control is advanced.

Here, when the vehicle behavior control is started on the vehicle 10 side when the intervention of the vehicle behavior control is not required, if the deviation before and after the threshold correction ΔThOS (ΔThUS) is small, the operation start threshold values before and after the correction are equal to each other. Since it is near, there is a low possibility that the driver will feel a sense of deceleration of the useless vehicle 10. In contrast, the greater the threshold correction front-rear deviation ΔThOS (ΔThUS), the higher the possibility that the driver will feel a sense of unnecessary deceleration of the vehicle 10. For this reason, the target value calculation unit adjusts the correction amount of the target turning behavior amount (target yaw rate Yr _tgt or target yaw moment My _tgt ) according to the threshold correction front-rear deviation ΔThOS (ΔThUS). In this example, the control gain K is used as the correction amount of the target turning behavior amount. Therefore, the target value calculation unit obtains the corrected target turning behavior amount by multiplying the target turning behavior amount by the control gain K. Equation 8 below shows an arithmetic expression of the corrected target yaw rate Yr _tgt-driver . Equation 9 below shows an arithmetic expression of the corrected target yaw moment My _tgt-driver .

Yr _tgt-driver = Yr _tgt * K (8)
My _tgt-driver = My _tgt * K (9)

As shown in FIG. 7, the control gain K (0 ≦ K ≦ 1) is set to “1” when the threshold correction front-rear deviation ΔThOS (ΔThUS) is equal to or smaller than a predetermined value ΔThOSx (ΔThUSx), and the threshold correction front-rear deviation ΔThOS ( If ΔThUS) is larger than a predetermined value ΔThOSx (ΔThUSx), the threshold correction before and after deviation ΔThOS (ΔThUS) is gradually decreased. In this example, the control gain K is reduced by a predetermined proportional coefficient. The predetermined value ΔThOSx (ΔThUSx) is, for example, the largest value or the largest value of the deviations before and after the threshold correction ΔThOS (ΔThUS) when the driver does not feel a sense of deceleration of the useless vehicle 10 by a calculation error or the like. What is necessary is just to set to the corrected value. In this example, for the convenience of explanation, the correction amount of the target yaw rate Yr _{tgt and} the correction amount of the target yaw moment My _tgt are both shown as the control gain K having the same numerical value. However, the control gain K may be a numerical value different between the correction amount of the target yaw rate Yr _{tgt and} the correction amount of the target yaw moment My _tgt .

  Here, the control gain K in FIG. 7 is for advancing the start of the vehicle behavior control and is different from that for delaying the start of the vehicle behavior control. For example, the control gain K for delaying the start of the vehicle behavior control is set to “1” regardless of the threshold correction deviation ΔThOS (ΔThUS).

  Hereinafter, the calculation processing operation in the vehicle behavior control apparatus of this modification will be described based on the flowchart of FIG.

The operation threshold value correcting unit corrects the operation start threshold values ThOS and ThUS (step ST1). The calculation process in step ST1 is performed in the same manner as in the first embodiment or the first modification, and the corrected operation start thresholds ThOS _driver and ThUS _driver are obtained.

The vehicle behavior control unit determines whether or not the operation of the vehicle behavior control is permitted (step ST2). In step ST2, the yaw rate deviation ΔYr is calculated, and the yaw rate deviation ΔYr is compared with the corrected operation start thresholds ThOS _driver and ThUS _driver . The vehicle behavior control unit determines that the absolute value of the yaw rate deviation ΔYr exceeds the corrected absolute value of the activation start threshold ThOS _driver , or the absolute value of the yaw rate deviation ΔYr is the corrected absolute value of the activation start threshold ThUS _driver . When it exceeds, it determines with the action | operation of vehicle behavior control being permitted. On the other hand, the vehicle behavior control unit determines that the absolute value of the yaw rate deviation ΔYr does not exceed the corrected operation start threshold value ThOS _driver , or the absolute value of the yaw rate deviation ΔYr is the corrected operation start threshold value ThUS _driver. If the absolute value is not exceeded, it is determined that the operation of the vehicle behavior control is not permitted. In other words, this case corresponds to a case where the yaw rate deviation ΔYr exists between the corrected operation start threshold value ThOS _driver and the corrected operation start threshold value ThUS _driver .

If the operation of the vehicle behavior control is not permitted, the vehicle behavior control unit once ends this calculation process. On the other hand, if the operation of the vehicle behavior control is permitted, the vehicle behavior control unit passes the process to the target value calculation unit. If the absolute value of the corrected operation start threshold value ThOS _driver (ThUS _driver ) is smaller than the absolute value of the corrected operation start threshold value ThOS (ThUS), the vehicle behavior control unit is required to promptly start the vehicle behavior control. If the absolute value of the corrected operation start threshold value ThOS _driver (ThUS _driver ) is larger than the absolute value of the operation start threshold value ThOS (ThUS) before correction, a delay in the operation of the vehicle behavior control is requested. Judge that

The target value calculation unit calculates the correction amount of the target turning behavior amount (target yaw rate Yr _tgt or target yaw moment My _tgt ) (step ST3). In this example, a control gain K that is a correction amount of the target turning behavior amount is obtained according to the actual turning state of the vehicle body. Specifically, a threshold correction front-rear deviation ΔThUS (ΔThOS) corresponding to the actual turning state of the vehicle body is calculated, and a control gain K corresponding to the threshold correction front-rear deviation ΔThUS (ΔThOS) is obtained. The control gain K is set to “1” when the threshold correction before and after deviation ΔThUS (ΔThOS) is equal to or less than a predetermined value ΔThUSx (ΔThOSx) when the vehicle behavior control is required to be started quickly, and the threshold correction before and after deviation ΔThUS (ΔThOS). ) Is larger than a predetermined value ΔThUSx (ΔThOSx), the threshold correction before and after deviation ΔThUS (ΔThOS) is gradually decreased. On the other hand, the control gain K is set to “1” when a delay in the operation of the vehicle behavior control is required.

The target value calculation unit calculates a target turning behavior amount (target yaw rate Yr _tgt or target yaw moment My _tgt ) (step ST4). In step ST4, if the target yaw rate Yr _tgt is to be obtained, the corrected target yaw rate Yr _tgt-driver is calculated from the above equation 8 based on the target yaw rate Yr _tgt before correction and the control gain K. Then, the target value calculation portion determines the target yaw rate _{Yr tgt-driver} of the corrected target yaw rate _{Yr tgt} in the vehicle behavior control. On the other hand, when _obtaining the target yaw moment My _tgt , the corrected target yaw moment My _tgt-driver is calculated from the above equation 9 based on the target yaw moment My _tgt before correction and the control gain K. Then, the target value calculation portion determines the target yaw moment _{My tgt-driver} of the corrected target yaw moment _{My tgt} in the vehicle behavior control.

  The target value calculation unit is required to quickly start the vehicle behavior control, and if the threshold correction back-and-forth deviation ΔThUS (ΔThOS) is larger than the predetermined value ΔThUSx (ΔThOSx), the target turning behavior amount and the actual turning behavior amount (That is, the target vehicle behavior control amount) is reduced.

The vehicle behavior control unit executes vehicle behavior control based on the target turning behavior amount (step ST5). For example, the target value calculation unit calculates a target vehicle behavior control amount (yaw rate deviation ΔYr or yaw moment deviation ΔMy) based on the target turning behavior amount (target yaw rate Yr _tgt or target yaw moment My _tgt ) obtained in step ST4. Calculate. The target vehicle behavior control amount can be said to be corrected by the control gain K if the target turning behavior amount is corrected by the control gain K (≠ 1). The vehicle behavior control unit performs vehicle behavior control according to the target vehicle behavior control amount.

  According to the vehicle behavior control device of this modified example, the driver's uncomfortable feeling can be suppressed by correcting the operation start threshold value ThOS (ThUS) of the vehicle behavior control in the same manner as in the first or modified example. In addition to this, the vehicle behavior control device is configured to control the target vehicle behavior control amount (yaw rate deviation ΔYr or yaw moment deviation) based on the deviation before and after the correction of the operation start threshold ThOS (ThUS) (threshold deviation before and after deviation ΔThOS (ΔThUS)). Since ΔMy) is changed, it is possible to suppress the occurrence of unnecessary deceleration for the vehicle 10 due to the early start of the vehicle behavior control. For this reason, this vehicle behavior control device may give an uncomfortable feeling of undesired deceleration to the driver when the deceleration is large, but this can also be suppressed.

[Modification 3]
By the way, the position of the center of gravity of the vehicle changes with the increase or decrease of the load or the increase or decrease of the occupant, for example. Since the change in the vehicle center of gravity position changes the relative distance L, the driver's feeling with respect to the vehicle behavior is further affected, which may increase the driver's discomfort.

  Therefore, the vehicle behavior control device of this modification is configured so that the vehicle behavior control in which the driver's uncomfortable feeling is further suppressed can be performed in the vehicle behavior control device of the embodiment or the first and second modifications. For this reason, the electronic control device 1 is provided with a center-of-gravity position calculation unit and a relative distance calculation unit.

The center-of-gravity position calculation unit calculates a vehicle center-of-gravity position that has changed from the reference vehicle center-of-gravity position due to an increase or decrease in cargo. The reference vehicle center-of-gravity position is, for example, the design center-of-gravity position of the vehicle 10 or the like. For example, when a load sensor is disposed on a suspension attachment portion of each wheel W _FL , W _FR , W _RL , W _RR , etc., the center-of-gravity position calculation unit is provided with each wheel W _FL , W _FR , W _RL , The position of the center of gravity of the vehicle can be obtained based on the change in the load of _WRR , the wheel base of the vehicle 10, and the like.

  The relative distance calculation unit calculates the relative distance L that has changed due to a change in the position of the center of gravity of the vehicle. The relative distance calculation unit calculates the relative distance L based on the seating position of the driver and the vehicle center of gravity position obtained by the center of gravity position calculation unit. The seating position of the driver is almost unchanged, so the designed position is used. However, since the driver's seat can be moved in the front-rear direction, etc., if the position of the driver's seat after the movement can be grasped, the relative distance calculation unit calculates the relative distance L when the driver's seat is moved. Information on the seating position of the driver based on the seat may be used. Therefore, the relative distance calculation unit calculates a new relative distance L when at least one of the vehicle gravity center position and the driver's seating position changes.

The electronic control device 1 of this modification uses the relative distance L corrected in accordance with the change in the position of the center of gravity of the vehicle and the seating position of the driver, and the speed in the vehicle lateral direction at the seating position of the driver from Equation 1 above. Obtain Vy. Therefore, in this modification, the yaw rate Yr _driver according to the amount of change in the center of gravity position of the vehicle and the seating position of the _driver is calculated, so that the operation start threshold ThOS (ThUS) corresponding to the amount of change is calculated. Correction is performed. Therefore, the vehicle behavior control device according to this modified example starts the vehicle behavior control at the operation start timing that is more in line with the actual situation of the vehicle 10 than the vehicle behavior control device according to the above-described embodiment or the first and second modified examples. This can reduce the driver's discomfort.

  Further, the electronic control unit 1 may be provided with a vehicle state correction unit that corrects the actual yaw rate Yr according to the changed position of the center of gravity of the vehicle. As a result, the vehicle behavior control device of this modified example starts vehicle behavior control at the operation start timing in accordance with the actual situation of the vehicle 10 as compared with the vehicle behavior control devices of the above-described embodiment or modified examples 1 and 2. Therefore, it is possible to further suppress the driver's uncomfortable feeling. According to this vehicle behavior control device, the target vehicle behavior control amount (yaw rate deviation ΔYr or yaw moment deviation ΔMy) can be obtained more in line with the actual situation of the vehicle 10. Increases accuracy. Further, in the vehicle behavior control device based on the modified example 2, by improving the accuracy of the actual yaw rate Yr, generation of unnecessary deceleration for the vehicle 10 due to the early start of the vehicle behavior control is further improved. Can be suppressed along.

DESCRIPTION OF SYMBOLS 1 Electronic controller 10 Vehicle 31 Braking part 32 Hydraulic pressure control part 43 Vehicle speed sensor 44 Wheel speed sensor 45 Yaw rate sensor 47 Lateral acceleration sensor _WFL , _WFR , _WRL , _WRR wheel

Claims (5)

A vehicle behavior control unit that controls the actual turning behavior amount of the vehicle body to the target turning behavior amount by applying braking torque to the wheel to be controlled;
An operation threshold value correction unit for correcting an operation start threshold value for determining the operation start of the vehicle behavior control based on the relative distance between the seating position of the driver and the vehicle gravity center position;
A vehicle behavior control device comprising:   The vehicle behavior control device according to claim 1, wherein the operation threshold correction unit further corrects the operation start threshold based on a vehicle speed.   The vehicle behavior control device according to claim 1, further comprising a target value calculation unit that corrects the target turning behavior amount according to a deviation before and after the correction of the operation start threshold value.   The target value calculation unit reduces a deviation between the actual turning behavior amount and the target turning behavior amount when the operation start timing of the vehicle behavior control is advanced in accordance with the correction of the operation start threshold value. The vehicle behavior control device according to claim 1, 2 or 3.   A relative distance calculation unit that calculates a relative distance between the seating position and the vehicle gravity center position when at least one of the driver's seating position and the vehicle gravity center position changes is provided. Item 5. The vehicle behavior control device according to 1, 2, 3, or 4.

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