JP2009262686A - Vehicle behavior control device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle behavior control device and a method for performing yawing moment control to easily predict a response of a yaw rate to steering during slow braking. <P>SOLUTION: When a control gain setting means sets a control gain for determining a control amount in the yawing moment control based on the vehicle longitudinal acceleration of a vehicle, the control gain is set to be small when the longitudinal acceleration is almost zero (non-braking time) in a region (slow braking time: low G region) where the longitudinal acceleration is smaller than a prescribed value. As a result, the response of the yaw rate to the steering during the slow braking becomes substantially the same as those during the non-braking time and in a high G region, and thereby the yawing moment control to easily predict the response of the yaw rate when an avoiding operation is performed is made possible. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle behavior control apparatus and a vehicle behavior control method for controlling a braking force of each wheel of a vehicle based on an input acting on the vehicle, a physical quantity generated in the vehicle, and the like and controlling the behavior.

In general, a vehicle behavior control device controls the behavior of a vehicle by generating a braking force difference between the left and right wheels of the vehicle and controlling the yawing moment of the vehicle. For example, a device as shown in Patent Document 1 below is known. It has been.
This vehicle behavior control device includes various sensors and control gain setting means. First, the yawing moment of the vehicle according to either the steering angle detected while the vehicle is traveling or the relative position of the vehicle ahead obstacle. Sets the control gain that determines the control amount of control. Next, the yaw moment control of the vehicle is performed by generating a braking force difference between the left and right wheels based on the control gain, the steering angular velocity and the steering angular acceleration set by the control gain setting means.

When the steering angle is small, the control gain is set to a small value to suppress the braking force control operation at a small steering angle and a large steering angular speed near the steering wheel neutral position. On the contrary, when the steering angle is large, the control gain is set to a large value. Increase the braking force control so that there is no phase lag.
As a result, it is possible to effectively intervene in the control and to perform yawing moment control without causing the driver to feel uncomfortable.
JP 2005-153617 A

By the way, when the control gain set by the control gain setting means is set based on the vehicle longitudinal acceleration, the minimum value of the control gain is “1”, and the control gain from when the longitudinal acceleration exceeds a predetermined value is set. Is set to gradually increase (FIG. 9 of cited document 1).
For this reason, in the region where the longitudinal acceleration is higher than the predetermined value (high G region: during sudden braking), the control gain changes according to the acceleration, and the response of the yaw rate to the steering is good and effective. In the region where the acceleration is lower than the predetermined value (low G region: during slow braking), the control gain does not change and is constant (“1”), so the variation range of the response of the yaw rate to the steering is large. .

Therefore, when yawing moment control based on vehicle longitudinal acceleration is performed during slow braking (low G region), there is a problem that it is difficult to predict the vehicle behavior and give a driver a sense of incongruity.
Therefore, the present invention has been devised to solve this problem, and the purpose thereof is vehicle behavior control capable of performing yawing moment control that makes it easy to predict the yaw rate response to steering even during slow braking. An apparatus and a vehicle behavior control method are provided.

In order to solve the above problems, the present invention provides:
When the control gain setting means sets a control gain for determining the feedforward control amount in the yawing moment control based on the vehicle longitudinal acceleration of the vehicle, the yaw rate acceleration is set over the substantially entire range of the longitudinal acceleration. It is set to be constant.

According to the present invention, the control gain that determines the feedforward control amount is set so that the yaw rate acceleration is constant over almost the entire longitudinal acceleration of the vehicle. Yawing moment control with easy response prediction can be performed.
That is, in a region where the longitudinal acceleration of the vehicle is smaller than a predetermined value (during slow braking), if the control gain is set to be lower than when the longitudinal acceleration is zero (during non-braking), steering during slow braking is performed. The response of the yaw rate to can be made substantially the same as when not braking or in the high G region.
As a result, yawing moment control that makes it easy to predict the response of the yaw rate when the avoidance operation is performed can be performed, and the avoidance operation can be assisted without causing the driver to feel uncomfortable.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.
(Constitution)
FIG. 1 is a schematic diagram showing a configuration of a drive system of a vehicle 100 including a vehicle behavior control device according to the present invention.
As shown in the figure, the vehicle 100 is a rear-wheel drive vehicle equipped with an engine 9, an automatic transmission 10, and a conventional differential gear (not shown) that transmits the power to the rear wheels 5RL and 5RR.

Further, the vehicle 100 is equipped with a control unit 8 and a brake fluid pressure control circuit 7 which are the main parts of the vehicle behavior control device according to the present embodiment, and thereby, the front wheels 5FL, 5FR and the rear wheels 5RL. The braking force (braking fluid pressure) of 5RR can be controlled independently.
In the figure, reference numeral 1 is a brake pedal, 2 is a booster, 3 is a master cylinder, and 4 is a reservoir. Normally, the braking fluid pressure boosted by the master cylinder 3 is supplied to the wheel cylinders 6FL to 6RR of the front wheels 5FL and 5FR and the rear wheels 5RL and 5RR according to the depression amount of the brake pedal 1 by the driver. It has become.

The brake fluid pressure control circuit 7 is interposed between the master cylinder 3 and the wheel cylinders 6FL to 6RR. The brake fluid pressure control circuit 7 includes a brake fluid pressure control circuit 7 for each wheel cylinder 6FL to 6RR. The brake fluid pressure is individually controlled.
The brake fluid pressure control circuit 7 uses a brake fluid pressure control circuit used for, for example, anti-skid control and traction control. In this embodiment, the brake fluid pressures of the wheel cylinders 6FL to 6RR are individually set. It is configured to be able to increase and decrease pressure.

The brake fluid pressure control circuit 7 controls the brake fluid pressures of the wheel cylinders 6FL to 6RR in accordance with the brake fluid pressure command value from the control unit 8.
Further, the vehicle 100 is provided with a drive torque controller 12, which is a drive wheel by controlling the operating state of the engine 9, the selected transmission ratio of the automatic transmission 10 and the throttle opening of the throttle valve 11. The driving torque to the wheels 5RL and 5RR is controlled.

Further, the operation state control of the engine 9 is controlled, for example, by controlling the fuel injection amount and the ignition timing or simultaneously adjusting the throttle opening. The drive torque controller 12 can control the drive torque of the rear wheels 5RL and 5RR independently. However, when the drive torque command value is input from the control unit 8, the drive torque command value is set. The drive wheel torque is controlled while referring to it.
Further, an external recognition sensor 14 is provided at the lower part of the vehicle body on the front side of the vehicle 100.

  The outside world recognition sensor 14 is constituted by a scanning type laser radar, and periodically irradiates a fine laser beam within a predetermined irradiation range in the forward direction of the vehicle while shifting in the horizontal direction by a certain angle. Based on the time difference from the emission timing to the light reception timing of the reflected light after receiving the reflected light reflected from the front object, the inter-vehicle distance L between the host vehicle and the front object at each angle, The width W and the relative speed ΔV are detected, and these detection signals are input to the control unit 8 as needed.

Further, the vehicle 100 is provided with an acceleration sensor 15, a yaw rate sensor 16, a brake stroke sensor 17, a steering angle sensor 20, and wheel speed sensors 21 FL to 21 RR, and each detection signal is sent to the control unit 8. It comes to input.
Here, the acceleration sensor 15 is a sensor that detects the longitudinal acceleration Xg and the lateral acceleration Yg that occur in the host vehicle during traveling, the yaw rate sensor 16 is a sensor that detects the yaw rate dψ, and the brake stroke sensor 17 is a brake sensor. This is a sensor for detecting the pedal stroke η. Further, the steering angle sensor 20 is a sensor that detects the steering angle θ of the steering wheel 19, and the wheel speed sensors 21FL to 21RR are sensors that detect the rotational speeds of the wheels 5FL to 5RR, that is, the wheel speed Vwj.

When the detected vehicle traveling state data has left and right directions, the left direction is the positive direction. That is, the yaw rate dψ, the lateral acceleration Xg, and the steering wheel angle (steering angle) θ are positive values when turning left.
Next, the control unit 8 described above comprises a microcomputer and its peripheral devices, and constitutes a control block as shown in FIG. 2 by software built in the ROM of the microcomputer.

This control block includes a relative position situation detection unit 31, a control gain setting unit 32, a steering angular velocity calculation unit 33, an F / F control yaw moment amount calculation unit 34, and an F / B control yaw moment amount calculation unit 35. , A corrected yaw moment amount calculation unit 36 and a braking force control unit 37 are provided.
Here, the relative position situation detection unit 31 exhibits a function of detecting the relative position situation of the host vehicle and the host vehicle front obstacle from the detection signal of the external recognition sensor 14.

The control gain setting unit 32 exhibits a function of setting control gains T1 and T2 for yawing moment control based on the relative position situation detected by the relative position situation detection unit 31 or the steering angle θ detected by the steering angle sensor 20. It is like that.
The steering angular velocity calculator 33 calculates a steering angular velocity dθ and a steering angular acceleration d (dθ) based on the steering angle θ detected by the steering angle sensor 20.

The F / F control yaw moment amount calculation unit 34 is based on the steering angular velocity dθ and steering angular acceleration d (dθ) calculated by the steering angular velocity calculation unit 33 and the control gains T1 and T2 set by the control gain setting unit 32. The function of calculating the yaw moment amount ΔMff by feedforward control is exhibited.
The F / B control yaw moment amount calculator 35 exhibits a function of calculating a yaw moment amount ΔMfb by feedback control.

The corrected yaw moment amount calculation unit 36 is based on the yaw moment amount ΔMff calculated by the F / F control yaw moment amount calculation unit 34 and the yaw moment amount ΔMfb calculated by the F / B control yaw moment amount calculation unit 35. Thus, the function of calculating the corrected yaw moment amount ΔM is exhibited.
Then, the braking force control unit 37 sets the braking force of each wheel based on the corrected yaw moment amount ΔM calculated by the corrected yaw moment amount calculating unit 36, converts the value into the target control hydraulic pressure P ^* , It is designed to output a control command through a hydraulic servo.

(Vehicle behavior control processing)
Next, the vehicle behavior control process performed by the control unit 8 configured as described above will be described with reference to the flowchart of FIG. The vehicle behavior control process is executed by a timer interrupt process every 10 msec, for example.
In this vehicle behavior control process, first, in step S1, various data from the sensors are read. Specifically, the steering wheel angle (steering angle) θ, vehicle speed V, brake pressure Pb, yaw rate dψ, longitudinal acceleration Xg, lateral acceleration Yg, and road surface μ detected by the sensors are read.

Next, the process proceeds to step S2, where the steering angular velocity dθ is calculated by differentiating the steering wheel angle (steering angle) θ read in step S1, and the steering angular acceleration d (dθ) is calculated by differentiating the steering angle θ. Calculate and move to step S3.
In step S3, the degree of urgency is detected from the sensor value read by performing a control gain calculation process to be described later, and the generated yaw moment gain T1 with respect to the steering angular velocity dθ of the feedforward control and the steering angular acceleration d (dθ) corresponding thereto. The generated yaw moment gain T2 is set.

Next, the process proceeds to step S4, and based on the steering angular velocity dθ and the steering angular acceleration d (dθ) calculated in step S2 and the feedforward control gains T1 and T2 set in step S3, the following ( Based on the equation (1), the brake yaw moment amount ΔMff by feedforward control is calculated, and the process proceeds to step S5.
ΔMff = τ1 × dθ + τ2 × d (dθ) (1)
In step S5, a brake yaw moment control amount ΔMfb based on feedback control using the target yawing momentum and the actual yawing momentum is calculated. That is, the target yaw rate dψ ^* is calculated based on the vehicle speed V and the steering angle θ, and then the deviation (or the change amount) between the target yaw rate dψ ^* and the actual yaw rate dψ is calculated, and the calculated state quantity Based on the above, the required correction moment amount ΔMfb is calculated.

Here, how to use these values is arbitrary, and, for example, feedback control that takes a linear sum of the above values by adding a control gain that is changed according to the running state is common.
Next, the process proceeds to step S6, and based on the following equation (2), the yaw moment amount ΔMff by the feedforward control calculated in step S4 and the yaw moment control amount ΔMfb by the feedback control calculated in step S5 The corrected yaw moment amount ΔM actually generated in the vehicle is calculated from the sum of the two.
ΔM = ΔMff + ΔMfb ……… (2)

As described above, this is effective only for feedback control (F / B control) because correction of unstable behavior and stability of disturbance are started after correction of yaw momentum occurs. However, the phase lag cannot be positively improved. On the other hand, only feedforward control (F / F control) can be expected to improve phase lag and improve responsiveness by controlling according to the steering wheel operation. If the amount is not accurate and large, the effect is small. Therefore, by taking the sum of the F / F control amount and the F / B control amount, the phase delay can be positively improved by the F / F control, while the stability can be ensured by the F / B control.
In step S7, the braking force of each wheel for realizing the corrected yaw moment amount ΔM is set, the value is converted into the target control hydraulic pressure P ^*, and control is performed through the hydraulic servo.

(Control gain calculation processing)
FIG. 4 shows the flow of the control gain calculation process in step S3.
As shown in the drawing, in the first step S30, a forward obstacle gain setting process described later is executed, and an emergency state determination flag emg_f, a collision time sensitive gain Kttc, an inter-vehicle distance sensitive gain Kl, and a lap amount sensitive gain Kw are set. Then, the process proceeds to the next step S31.
In step S31, a vehicle speed sensitive gain Kv is set based on the vehicle speed V with reference to a vehicle speed sensitive gain calculation map as shown in FIG.

This vehicle speed sensitive gain calculation map is set so that the control gain increases from “0” to “1” as the vehicle speed V increases. When the emergency state determination flag F set in step S31 is set to “1” indicating that there is an obstacle ahead of the host vehicle, as shown by the solid line in FIG. The control gain is set larger than that in the normal state (broken line) in which the emergency state determination flag F is reset to “0” indicating that there is no emergency state.
Here, basically, it can be said that the degree of urgency tends to become dangerous as the vehicle speed increases, and also increases because damage increases.

Next, in step S32, a steering angular velocity gain setting process, which will be described later, is executed to set a steering angular velocity gain Kdθ and a steering angular velocity sensitive gain Kvsa. Then, the process proceeds to step S33, and a steering angular acceleration gain as shown in FIG. With reference to the calculation map, the steering angular acceleration gain Kd (dθ) is set based on the steering angular velocity d (dθ).
This steering angular acceleration gain calculation map is set so that the control gain increases from “1” as the steering angular acceleration d (dθ) increases. In the emergency avoidance state, the avoidance operation becomes faster as the avoidance distance becomes shorter. Therefore, the driver performs the steering operation quickly, so that the degree of emergency is high according to the magnitude of the steering angular acceleration.

Next, in step S34, referring to a road surface friction coefficient gain calculation map as shown in FIG. 7, a road surface friction coefficient gain Kμ is set based on the road surface friction coefficient μ. The road surface friction coefficient μ is estimated from the longitudinal acceleration Xg, the lateral acceleration Yg, etc., or the road surface friction coefficient value μ sent from the infrastructure side by road-to-vehicle communication is applied.
Here, when the μ value of the road surface is small, the force that can be generated by the tire is smaller than when the road surface is large. Therefore, a phase delay occurs even with a small steering wheel operation, and unstable behavior is likely to occur. The degree is high. For this reason, it is necessary to compensate for the phase by the yaw moment control from a relatively slow steering operation speed state. On the other hand, since the driver recognizes that it is not normal on a slippery road surface, the driver feels more uncomfortable with the deceleration G. The effect of improving vehicle behavior can be learned.

Next, in step S35, a lateral acceleration gain KYg is set based on the lateral acceleration Yg with reference to a lateral acceleration gain calculation map as shown in FIG. This lateral acceleration gain calculation map is set so that the control gain increases from 1 as the lateral acceleration Yg increases.
In a state where the lateral acceleration Yg is large, a component in the deceleration G direction occurs due to the turning resistance due to cornering force at the time of turning, so it becomes difficult to understand the uncomfortable feeling due to the deceleration G, and the vehicle motion state is also near the tire friction limit. Since the phase lag becomes relatively large due to the decrease in the tire Cp, it is necessary to increase the gain for phase compensation, and unstable behavior exceeding the tire friction limit is likely to occur, and the degree of urgency is high.

  Next, in step S36, the vehicle longitudinal acceleration gain KXg is set based on the vehicle longitudinal deceleration Xg with reference to the vehicle longitudinal acceleration gain calculation map as shown in FIG. During slow braking (low G range), the wheel load on the front is increased and the yaw rate response to steering is fast, which makes the driver feel uncomfortable during yaw moment control. In this vehicle longitudinal acceleration gain calculation map, the control gain is set to be smaller than “1” in a region where the vehicle longitudinal acceleration Xg is small (during slow braking), and in a region where the vehicle longitudinal acceleration is large (during sudden braking), The control gain is set to increase from “1”.

  The vehicle longitudinal acceleration gain Xg based on the vehicle longitudinal acceleration gain calculation map in step S36 is a characteristic part of this embodiment, and will be described in detail later. It is difficult to understand the sense of incongruity due to the deceleration G, and the degree of urgency is high because a sudden braking with a large deceleration G is assumed to be a collision and emergency avoidance to avoid it.

  Next, in step S37, referring to a brake fluid pressure gain calculation map as shown in FIG. 11, the brake fluid pressure gain KPb is determined based on the braking force, the brake operation stroke or the brake pressure corresponding to the driver's brake operation amount. Set. This brake fluid pressure gain calculation map is set so that the control gain increases as the brake operation amount increases.

Next, in step S38, based on the following equation (3), take the maximum value of the control gain according to each state and the urgency of the operation amount obtained in steps S30 to 37 (select high). To set the gain Kx relating to the urgency.
Kx = max (K, K, K, Kdθ, Kvsa, Kd (dθ), Kμ, KYg,
KXg, KPb) ……… (3)
Here, max () is a function that selects the maximum value in parentheses.
Then, the process proceeds to step S39, the yaw moment gains T1 and T2 for calculating the yaw moment of the feedforward control are calculated based on the following equations (4) and (5), and the timer interruption process is terminated. Then, the program returns to the predetermined main program.
T1 = Kv × Kx × T01 (4)
T2 = Kv × Kx × T02 (5)

(First embodiment of vehicle longitudinal acceleration gain)
Next, FIG. 10 is a graph showing a vehicle yaw rate characteristic for creating a calculation map of the vehicle longitudinal acceleration gain KXg shown in FIG. 9, which is a characteristic part of the present embodiment.
In general, the yaw rate characteristic of a vehicle is such that the yaw rate acceleration increases as the longitudinal acceleration Xg increases in the low G region (Width_Xg) during non-braking to slow braking when the longitudinal acceleration Xg is zero (0) as shown by the broken line in the figure. It has a parabolic shape that once rises and then slowly descends. Thereafter, the yaw rate acceleration decreases as the longitudinal acceleration Xg increases. On the other hand, it is desirable that the target yaw rate acceleration value of the vehicle by control is constant (flat) over the entire area as shown by the solid line in FIG.

On the other hand, in the conventional vehicle longitudinal acceleration gain calculation map, the control gain KXg is constant in the range of the low G region (Width_Xg) at the time of gentle braking, that is, “1.0”. Not consistent with yaw rate characteristics. Therefore, in the range of the low G region (Width_Xg) at the time of the gentle braking, the vehicle yaw rate acceleration target value by the control is deviated, which makes it difficult to predict the vehicle behavior and gives the driver a sense of incongruity. I understood.
Therefore, in the present embodiment, as shown in FIG. 9, the vehicle longitudinal acceleration gain calculation map has a parabola (width: Width_Xg) opposite to the yaw rate characteristic of the vehicle by changing in the low G region (Width_Xg) during slow braking. , Size: dKXg).

(Effects of the first embodiment)
As a result, the deviation in the low G region at the time of slow braking is canceled and the yaw rate acceleration can be controlled so as to substantially match the target value over the entire region. It is almost the same as the high G region. As a result, yawing moment control that makes it easy to predict the yaw rate response when the avoidance operation is performed can be performed, and the avoidance operation can be assisted without causing the driver to feel uncomfortable.

In this embodiment, as shown in FIG. 9, the control gain is lowered to a reverse parabola for the entire range of the low G region (Width_Xg) during slow braking, but as shown in FIG. Of the regions, only the region having the highest yaw rate acceleration (Width1_Xg) may be partially lowered.
Further, the vehicle longitudinal acceleration gain calculation map as shown in FIG. 9 is an example of the present embodiment, and depends on the load and weight of the steering wheel of the vehicle 100, the friction coefficient of the road surface, the vehicle speed and the like as described below. Therefore, it is used by changing to another vehicle longitudinal acceleration gain calculation map having a different area (Width_Xg) or size (dKXg).

(Second Embodiment)
Next, a second embodiment relating to this vehicle longitudinal acceleration gain calculation map will be described.
First, in the flow of FIG. 12, an optimal vehicle longitudinal acceleration gain calculation map corresponding to a vehicle in which the vehicle weight W varies greatly depending on the presence or absence of luggage or passengers such as trucks and buses is calculated. It is selected from the map and applied.
As shown in the figure, the vehicle weight W is calculated from the wheel load (for example, the front wheels 5FL, 5FR) in the first step S100, and the process proceeds to the next step S102, where the vehicle weight W is compared with the specified load Wn. It is determined whether or not the load is larger than the specified load Wn.

When it is determined that the vehicle weight W is less than the specified load Wn as a result of this determination processing (No), the vehicle longitudinal acceleration control gain KXg is used as it is by using a standard vehicle longitudinal acceleration gain calculation map as shown in FIG. Ask for.
On the contrary, when it is determined that the vehicle weight W is larger than the specified load Wn (Yes), the process proceeds to step S104 and the control gain is “1.0” as shown by the solid line in FIG. A vehicle longitudinal acceleration gain calculation map (Width_Xg-Gain_W1) having a narrow region below the vehicle width is selected, and a vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map.
That is, when the vehicle weight W is large, the wheel load is also large. Therefore, the vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map in which the region for decreasing the control gain is small.

(Effects of the second embodiment)
As a result, even if the vehicle weight (wheel load) W changes, the response of the yaw rate to the steering becomes the same regardless of the vehicle weight, so that the avoidance operation can be assisted without giving the driver a sense of incongruity.

(Third embodiment)
Next, the flow of FIG. 14 shows a third embodiment relating to the vehicle longitudinal acceleration gain calculation map, and is suitable for the case where the friction coefficient of the road surface changes, such as during a snowy road or rain. The vehicle longitudinal acceleration gain calculation map is changed to be used.
As shown in the drawing, the friction coefficient μMYU of the road surface is measured in the first step S200, and the process proceeds to the next step S202 to determine whether or not the road surface μMYU has fallen below a predetermined value μMYun.
As a result, when it is determined that the road surface μMYU is not less than the predetermined value μMYY (No), the vehicle longitudinal acceleration control gain KXg is obtained based on the standard vehicle longitudinal acceleration gain calculation map as shown in FIG. .

On the other hand, when it is determined that the road surface μMYU has fallen below the predetermined value μMYUn (Yes), the process proceeds to step S204, and the control gain falls below “1.0” as shown by the solid line in FIG. A vehicle longitudinal acceleration gain calculation map (Width_Xg-Gain_MYU1) having a narrow region (low G region) is selected, and a vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map.
That is, when the road surface μMYU is low, the lateral force that can be generated by the tire is also small. Therefore, the vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map in which the region where the control gain is reduced is small.
(Effect of the third embodiment)
Thus, even if the road surface μMYU changes, the response of the yaw rate to the steering becomes the same regardless of the road surface μMYU, and thus the avoidance operation can be assisted without giving the driver a sense of incongruity.

(Fourth embodiment)
Next, the flow of FIG. 15 shows a fourth embodiment relating to this vehicle longitudinal acceleration gain calculation map. When the vehicle speed VI of the vehicle 100 changes greatly, the vehicle longitudinal acceleration gain calculation suitable for it is performed. It was changed to a map and used.
As shown in the drawing, the vehicle speed VI is measured in the first step S300, and the process proceeds to the next step S302 to determine whether or not the vehicle speed VI exceeds a predetermined speed VIn.
As a result, when it is determined that the vehicle speed VI does not exceed the predetermined speed VIn (No), the vehicle longitudinal acceleration control gain KXg is directly set based on a standard vehicle longitudinal acceleration gain calculation map as shown in FIG. Ask.

On the other hand, when it is determined that the vehicle speed VI has exceeded the predetermined speed VIn (Yes), the process proceeds to step S304, and as shown by the solid line in FIG. A vehicle longitudinal acceleration gain calculation map (dKXg-Gain_V1) having a small value is selected, and a vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map.
That is, when the vehicle speed VI is high, the lateral force that can be generated by the tire is also small. Therefore, the vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map in which the amount (dKXg) for decreasing the control gain is small. It will be.
(Effect of 4th Embodiment)
Thereby, the response of the yaw rate to the steering becomes the same regardless of the vehicle speed, so that the avoidance operation can be assisted without giving the driver a sense of incongruity.

(Fifth embodiment)
Next, the flow of FIG. 17 shows a fifth embodiment relating to the vehicle longitudinal acceleration gain calculation map. When the vehicle 100 is traveling on a slope (slope), the vehicle This is used by changing to an acceleration gain calculation map.
As shown in the figure, in the first step S400, a gradient road determination flag is generated as to whether or not the traveling road is a gradient road, and the process proceeds to the next step S402 to check whether the gradient road determination flag is ON. It is determined whether or not the vehicle 100 is traveling on a slope.
As a result, when it is determined that the gradient road determination flags are not ON (No), the vehicle longitudinal acceleration control gain KXg is obtained as it is based on a standard vehicle longitudinal acceleration gain calculation map as shown in FIG.

On the other hand, when it is determined that the gradient road determination Flags is ON (Yes), the process proceeds to step S404, and it is further determined whether or not it is a downhill.
As a result, when it is determined that the gradient road is a downhill (Yes), the process proceeds to the next step S406, and the region where the control gain is below “1.0” (low G) as shown by the solid line in FIG. A vehicle longitudinal acceleration gain calculation map (Width_Xg-Gein_Slope1) having a narrow area) is selected, and a vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map.

On the other hand, when it is determined in step S404 that the gradient road is not downhill (No), the process proceeds to step S408, and it is determined whether or not it is an uphill.
As a result, when it is determined that the vehicle is not uphill (No), it is determined that the gradient road determination Flags = ON in step SS402 is invalid, and is directly based on a standard vehicle longitudinal acceleration gain calculation map as shown in FIG. A vehicle longitudinal acceleration control gain KXg is obtained.

On the other hand, when it is determined that the vehicle is on an uphill (Yes), the process proceeds to step S410, and a region where the control gain is less than “1.0” (low G region) as shown by a one-dot broken line in FIG. A narrow vehicle longitudinal acceleration gain calculation map (Width_Xg + Gein_Slope1) is selected, and a vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map.
That is, when the vehicle 100 is traveling downhill, the actual wheel load (front wheels 5FL, 5FR) is larger than the target deceleration. The vehicle longitudinal acceleration control gain KXg is selected based on this vehicle longitudinal acceleration gain calculation map.

Conversely, when the vehicle 100 is traveling on an uphill, the actual wheel load (front wheels 5FL, 5FR) is smaller than the target deceleration, so the vehicle longitudinal acceleration gain calculation map has a large control gain reduction area. And the vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map.
(Effect of 5th Embodiment)
This makes it possible to set the gain according to the wheel load on the downhill and the uphill, and the yaw rate response to the steering becomes the same, so the avoidance operation can be assisted without giving the driver a sense of incongruity. .

(Sixth embodiment)
Next, the flow of FIG. 19 shows a sixth embodiment relating to the vehicle longitudinal acceleration gain calculation map. In the present embodiment, as shown in FIG. 20, when turning steering is performed to avoid an obstacle 101 such as a stopped vehicle or a low-speed traveling vehicle while the vehicle 100 is turning (curve traveling), The vehicle longitudinal acceleration gain calculation map suitable for the turning direction is changed to be used.

As shown in the figure, in the first step S500, a turning judgment flag is generated as to whether or not the vehicle is making a turn to avoid the obstacle 101, and the process proceeds to the next step S502, where the turning judgment flag is determined. It is determined whether or not the vehicle is turned on, that is, whether or not the vehicle 100 is turning for avoidance.
As a result, when it is determined that the turning determination flags are not ON (No), the vehicle longitudinal acceleration control gain KXg is obtained as it is based on a standard vehicle longitudinal acceleration gain calculation map as shown in FIG.

On the contrary, when it is determined that the turning determination Flags is ON (Yes), the process proceeds to step S504, and it is further determined whether or not it is avoidance to the inside of the turning (A in FIG. 20). to decide.
As a result, when it is determined that the vehicle is to avoid turning inside (A in FIG. 20) (Yes), the process proceeds to the next step S506, and the control gain is “1.0” as shown by the solid line in FIG. A vehicle longitudinal acceleration gain calculation map ((Width_Xg + dKXg) -Gein_Circle1) with a lower region (low G region) and a smaller amount is selected, and a vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map.

On the other hand, when it is determined that the avoidance to the inside of the turn (A in FIG. 20) is not (No) in the determination process of Step S504, the process proceeds to Step S508 and the avoidance to the outside of the turn (B in FIG. 20). Determine whether.
As a result, when it is determined that it is not avoiding to the outside of the turn (B in FIG. 20) (No), it is determined that the turn determination Flags = ON in step S502 is invalid, and the standard as shown in FIG. A vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map.

  On the other hand, when it is determined that the avoidance is to the outside of the turn (B in FIG. 20) (Yes), the process proceeds to step S510 and the control gain is “1.0” as shown by the one-dot broken line in FIG. A vehicle longitudinal acceleration gain calculation map ((Width_Xg + dKXg) + Gein__Circle2) having a large area and a low amount (low G region) is selected, and a vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map. .

That is, when the vehicle 100 is turning, the load is shifted to the outside of the turn. Therefore, when avoiding the turn inside using the inside of the turn with a small load, the vehicle longitudinal acceleration gain that reduces the control gain is decreased and the amount is reduced. A calculation map is selected, and the vehicle longitudinal acceleration control gain KXg is obtained based on the vehicle longitudinal acceleration gain calculation map.
On the other hand, when avoiding turning outside using a turning outer wheel with a heavy load, select the vehicle longitudinal acceleration gain calculation map that increases the control gain reduction area and the amount, and based on this vehicle longitudinal acceleration gain calculation map, select the vehicle longitudinal acceleration gain calculation map. The acceleration control gain KXg is obtained.

(Effect of 6th Embodiment)
As a result, when turning, it becomes possible to set the gain according to the wheel load of each wheel, and the response of the yaw rate to the steering becomes the same, so the avoidance operation can be assisted without giving the driver a sense of incongruity.

It is the schematic which showed the structure of the drive system of the vehicle behavior control apparatus which concerns on this invention, and the vehicle 100 provided with the same. It is a block diagram which shows the specific example of the control unit 8 shown in FIG. It is a flowchart which shows the vehicle behavior control process performed with the control unit 8 of FIG. 1 in embodiment of this invention. It is a flowchart which shows the control gain calculation process in the vehicle behavior control process of FIG. It is a figure which shows an example of a vehicle speed sensitive gain calculation map. It is a figure which shows an example of a steering angular acceleration gain calculation map. It is a figure which shows an example of a road surface friction coefficient gain calculation map. It is a figure which shows an example of a lateral acceleration gain calculation map. It is a figure which shows an example of the standard longitudinal acceleration gain calculation map which concerns on this Embodiment. It is a figure which shows the yaw rate characteristic of a vehicle. It is a figure which shows an example of a brake fluid pressure gain calculation map. It is a flowchart which shows the flow of the selection process of the longitudinal acceleration gain calculation map in case a vehicle weight differs. It is a figure which shows an example of the longitudinal acceleration gain calculation map in case the vehicle weight and the friction coefficient of a road surface differ. It is a flowchart which shows the flow of selection processing of the longitudinal acceleration gain calculation map in case the friction coefficients of a road surface differ. It is a flowchart which shows the flow of the selection process of the longitudinal acceleration gain calculation map in case vehicle speeds differ. It is a figure which shows an example of the longitudinal acceleration gain calculation map in case vehicle speeds differ. It is a flowchart which shows the flow of the selection process of the longitudinal acceleration gain calculation map at the time of hill running. It is a figure which shows an example of the longitudinal acceleration gain calculation map at the time of slope running. It is a flowchart which shows the flow of the selection process of the longitudinal acceleration gain calculation map at the time of turning avoidance during turning driving. It is a figure explaining the operation | movement in the turning avoidance during turning driving | running | working. It is a figure which shows an example of the longitudinal acceleration gain calculation map at the time of turning avoidance during turning driving.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Vehicle 5FL, 5FR ... Front wheel 5RL, 5RR ... Rear wheel 7 ... Braking fluid pressure control circuit
8 ... Control unit
9 ... Engine
10 ... Automatic transmission 12 ... Drive torque controller
14 ... External recognition sensor
15 ... Acceleration sensor
16 ... Yaw rate sensor
17 ... Master cylinder pressure sensor
18 ... Steering actuator 20 ... Steering angle sensor
21FL-21RR ... Wheel speed sensor

Claims (18)

A vehicle behavior control device that generates a braking force difference between left and right wheels of a vehicle and performs yawing moment control of the vehicle,
A control gain setting means for setting a control gain for determining a feedforward control amount in the yawing moment control;
The control gain setting means sets the control gain set based on the vehicle longitudinal acceleration of the vehicle so that the yaw rate acceleration is constant over substantially the entire range of the longitudinal acceleration. . The vehicle behavior control device according to claim 1,
The control gain setting means sets the control gain set based on the vehicle longitudinal acceleration of the vehicle so that the longitudinal gain is lower than when the longitudinal acceleration is zero in a region where the longitudinal acceleration is smaller than a predetermined value. A vehicle behavior control device. The vehicle behavior control device according to claim 1,
The control gain setting means sets a control gain in a region where the yaw rate acceleration exceeds a predetermined value among the control gains set based on the vehicle longitudinal acceleration of the vehicle by lowering the predetermined value. Vehicle behavior control device. In the vehicle behavior control device according to any one of claims 1 to 3,
The vehicle behavior control device, wherein the control gain setting means changes the set control gain in accordance with a wheel load of the vehicle. In the vehicle behavior control device according to any one of claims 1 to 4,
The vehicle behavior control device, wherein the control gain setting means changes the set control gain according to the weight of the vehicle. In the vehicle behavior control device according to any one of claims 1 to 5,
The vehicle behavior control device, wherein the control gain setting means further changes the set or changed control gain according to a friction coefficient of a road surface. In the vehicle behavior control device according to any one of claims 1 to 6,
The vehicle behavior control device, wherein the control gain setting means further changes the set or changed control gain according to the speed of the vehicle. In the vehicle behavior control device according to any one of claims 1 to 7,
The said control gain setting means changes the control gain after the said setting or a change according to the gradient road, when the said vehicle is drive | working the gradient road. In the vehicle behavior control device according to any one of claims 1 to 8,
The control gain setting means is changed so that when the vehicle is turning, when the vehicle further turns inside the turn, a region and amount of the control gain to be lowered after the setting or change are reduced. The vehicle behavior control device is characterized in that, when the vehicle is turned to the outside of the turn, the region and amount of the control gain after the setting or change are decreased so as to increase. A vehicle behavior control method for generating a braking force difference between left and right wheels of a vehicle based on an input acting on the vehicle and a physical quantity generated in the vehicle and performing yawing moment control of the vehicle,
A control gain setting step for setting a control gain for determining a feedforward control amount in the yawing moment control;
In the control gain setting step, when the control gain is set based on the vehicle longitudinal acceleration of the vehicle, the control gain is set so that the yaw rate acceleration is constant over almost the entire longitudinal acceleration. A characteristic vehicle behavior control method. The vehicle behavior control method according to claim 10,
In the control gain setting step, when the control gain is set based on the vehicle longitudinal acceleration of the vehicle, the control gain is set in the region where the longitudinal acceleration is smaller than a predetermined value with respect to when the longitudinal acceleration is zero. The vehicle behavior control method is characterized in that the vehicle behavior is set to be lowered. The vehicle behavior control method according to claim 10,
When the control gain is set based on the vehicle longitudinal acceleration of the vehicle, the control gain setting step lowers the control gain in a region where the yaw rate acceleration exceeds a predetermined value from the predetermined value. The vehicle behavior control method characterized by setting. The vehicle behavior control method according to any one of claims 10 to 12,
In the control gain setting step, the set control gain is changed according to a wheel load of the vehicle. The vehicle behavior control method according to any one of claims 10 to 13,
In the control gain setting step, the set control gain is changed according to the weight of the vehicle. The vehicle behavior control method according to any one of claims 10 to 14,
In the control gain setting step, the control gain after setting or changing is further changed according to a friction coefficient of a road surface. The vehicle behavior control method according to any one of claims 10 to 15,
In the control gain setting step, the control gain after setting or changing is further changed according to the speed of the vehicle. The vehicle behavior control method according to any one of claims 10 to 16,
In the control gain setting step, when the vehicle is traveling on a slope road, the control gain after the setting or change is changed according to the slope road. The vehicle behavior control method according to any one of claims 10 to 17,
The control gain setting step is changed so that when the vehicle is turning, when the vehicle further turns inside the turn, the region and amount of the control gain to be lowered after the setting or change are reduced. The vehicle behavior control method is characterized in that when the vehicle is turned to the outside of the turn, the region and amount of the control gain to be lowered after the setting or change are increased.

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