JPH10273029A - Attitude control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a brake from being overworked by regulating attitude control, when the condition executing attitude control is continued over a fixed time. SOLUTION: At first, it is discriminated whether a flag F is zero or not, but the flag F is set to be one (Q1) where attitude control is executed. In the case of NO in this discrimination, it is discriminated whether posture control is completed or not (Q4), and in the case of NO, a yaw angle Y is computed based on yaw rate (Q5). Next, deviation of the yaw angle Y against a reference yaw angle is added, and an integrated value Y1 to be an added value of the deviation is computed (Q6). It is discriminated whether the integrated value Y1 is larger than a fixed value or not (Q7). In the case of YES, there is high possibility of sport running, and hence is addition to stopping the posture control, warning is executed (Q8) for letting persons sufficiently recognizing stop of the posture control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle attitude control device.

[0002]

2. Description of the Related Art In recent vehicles, there is a tendency that the attitude of the vehicle is controlled by independently controlling the braking force applied to each wheel. That is, based on the steering angle, the vehicle speed, the actual lateral acceleration acting on the vehicle, the yaw rate, and the like, the target posture state is given as, for example, a target yaw rate or a target side slip angle of the vehicle body, and the actual yaw rate becomes the target yaw rate. A braking force is applied to a predetermined wheel so as to be a yaw rate or an actual sideslip angle becomes a target sideslip angle (for example, see Japanese Patent Application Laid-Open No. 2-151571). . Such attitude control can prevent understeer and spin within the limits of the grip force of wheels, that is, tires, and is attracting attention as a kind of future vehicle safety technology.

[0003]

The above-mentioned attitude control is performed by applying a braking force to the wheels, so that the abuse of the brake is a problem.
In particular, some drivers may perform sports driving to actively disturb the attitude of the vehicle, and if such running is repeated continuously or within a short time. The brake may be faded.

[0004] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle attitude control device capable of preventing a situation in which a brake is overworked.

[0005]

Means for Solving the Problems To achieve the above object, the present invention provides the following as a first solution. That is, in the attitude control device of the vehicle which controls the attitude of the vehicle by independently controlling the braking force on each wheel, when the attitude control is continuously performed for a predetermined time or more. Or, when the posture control is performed a predetermined number of times or more within a predetermined time, a regulating means for regulating the posture control is provided.

In order to achieve the above object, the present invention provides a second solution as follows. That is, in a vehicle attitude control device that controls the vehicle attitude by independently controlling the braking force on each wheel, the vehicle yaw is controlled in a state where the lateral acceleration acting on the vehicle body is equal to or greater than a predetermined value. When the integral value of the angle is equal to or larger than a predetermined angle, the control unit includes a regulating unit that regulates the posture control.
It is like that.

In order to achieve the above object, the present invention provides a third solution as follows. That is, in a vehicle attitude control device that controls the attitude of the vehicle by independently controlling the braking force on each wheel, when the integrated value of the yaw angle of the vehicle is equal to or greater than a predetermined angle, It is provided with a regulation means for regulating the control. Preferred embodiments based on each of the above-described solutions are as described in claims 4 and subsequent claims.

[0008]

According to the first aspect of the present invention, when it is highly probable that the driver is actively traveling while disturbing the attitude of the vehicle, the attitude control is restricted. The frequency or degree of use of the brake is reduced as compared with the above, and it is possible to prevent the abuse of the brake. Especially,
Since it is determined that the vehicle is actively disturbing the attitude of the vehicle based on the duration of the attitude control or the number of times the attitude is controlled within a predetermined time, the attitude of the vehicle is actively determined. By easily and comprehensively knowing whether or not the vehicle is running disturbed, it is possible to satisfy both the required posture control and the overuse of the brake at a high level.

According to the second aspect, when it is highly probable that the driver is running while actively disturbing the attitude of the vehicle,
Since the posture control is restricted, the frequency or degree of use of the brake is reduced as compared with the case where no restriction is imposed, and it is possible to prevent abuse of the brake. In particular, when the condition that the integrated value of the yaw angle is equal to or more than the predetermined angle is satisfied in addition to the condition that the lateral acceleration acting on the vehicle is equal to or more than the predetermined value, the posture of the vehicle is positively disturbed. It is set to judge that the vehicle is traveling in a correct way, so it is possible to accurately know whether or not the vehicle is actively disturbing the posture of the vehicle, to secure the necessary posture control and prevent overuse of brakes Can be satisfied at a high level.

According to the third aspect, when it is highly probable that the driver is running while actively disturbing the attitude of the vehicle,
Since the posture control is restricted, the frequency or degree of use of the brake is reduced as compared with the case where no restriction is imposed, and it is possible to prevent abuse of the brake. In particular, since the running in which the posture of the vehicle is positively disturbed is set such that the integrated value of the yaw angle becomes a predetermined angle or more, the driving in which the posture of the vehicle is positively disturbed is performed. By easily knowing whether or not there is, it is possible to satisfy both the required posture control and the prevention of heavy use of the brakes at a high level.

According to the fourth aspect, a specific method for regulating the attitude control is provided. In particular, when the attitude control is stopped, it is extremely effective in avoiding overuse of the brake. Also, reducing the control amount of the attitude control
This is preferable for preventing a sudden change in braking force before and after regulation.

According to the fifth aspect, by stalling the engine, the vehicle can be decelerated without relying on the brake, which is extremely preferable for safety. According to the sixth aspect, it is preferable that the warning sound clearly informs the driver of the restriction on the posture control.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a vehicle attitude control apparatus (Stability Control) according to the present invention is shown.
1 System: a vehicle to which SCS is applied), 1 is a vehicle body, 2, 2,... are four sets of hydraulic systems individually disposed on four front and rear wheels 21FR, 21FL, 21RR, 21RL. The brake 3 is a pressurizing unit for supplying a hydraulic fluid to each of the brakes 2, and the hydraulic unit 4 is a hydraulic unit (hereinafter, referred to as a hydraulic unit) which distributes the hydraulic fluid supplied from the pressurizing unit 3 to each of the brakes 2. , Simply H
U, and these brakes 2, 2,..., The Kajo unit 3 and the HU 4 constitute a braking means. 5 is an SCS controller for controlling the operation of each of the brakes 2 via the pressurizing unit 3 and the HU 4; 6, 6,... Are wheel speed sensors for detecting the rotational speed of each of the wheels 21; A lateral G sensor for detecting lateral acceleration acting on 1; a yaw rate sensor 8 for detecting a yaw rate acting on the vehicle body 1; and a steering amount detection 9 for detecting a steering angle of a driver. This is a steering angle sensor as a means.

10 is a master shilling, 11 is an engine, 12 is an automatic transmission, 13
Is an EGI controller that adjusts the fuel injection amount according to the number of revolutions of the engine 11, the intake air amount, and the like.

The brakes 2, 2,... Are, as shown in FIG. 2, a brake 2 for the right front wheel 21FR and a left rear wheel 21R.
L is connected to the master cylinder 10 by the first hydraulic line 22a, and the brake 2 of the left front wheel 21FL and the brake 2 of the right rear wheel 21RR are different from the first hydraulic line 22a. The two hydraulic lines 22b are connected to the master cylinder 10, thereby forming two independent brake systems of the so-called X pipe type. Then, the wheels 21FR, 21FR are turned on in accordance with the depression operation of the brake pedal 14 by the driver.
RL,... Are given a braking force.

The Kajo unit 3 comprises the first and second
Hydraulic pumps 31a and 31b connected to the hydraulic lines 22a and 22b, respectively, and these hydraulic pumps 31a and 31b.
b, and cut valves 32a, 32b respectively disposed in the first and second hydraulic lines 22a, 22b so that the master cylinder 10 can be connected and disconnected, and the cut valves 32a, 32b, the master cylinder 10 and And a liquid sensor 33 for detecting the liquid level between the two. And
The cut valves 32a and 32b are closed in response to a command from the SCS controller 5, whereby the hydraulic fluid discharged from the hydraulic pumps 31a and 31b is transferred via the HU4 regardless of the brake operation by the driver. Are supplied to the brakes 2, 2,.

The HU 4 is, as shown in FIG.
Each of the brakes 2 is connected to a reservoir tank 42 with a pressurizing valve 41, 41,... Which pressurizes each brake 2 with a pressure liquid supplied through the first hydraulic line 22a or the second hydraulic line 22b. And pressure reducing valves 43, 43,. The opening degree of each of the above-mentioned each of the pressure control valves 41 and each of the pressure reducing valves 43 is adjusted to increase or decrease according to a command from the SCS controller 5, so that the hydraulic pressure applied to each of the brakes 2 is reduced and the braking force is reduced. It is configured to be increased or decreased.

The SCS controller 5 includes the wheel speed sensors 6, 6,..., The lateral G sensor 7, and the yaw rate sensor 8.
The turning posture of the vehicle is determined based on the input signal from the steering angle sensor 9, and the operation of the pressurizing unit 3 and the HU 4 is controlled according to the determination result, while the input signal from the liquid sensor 33 is controlled. The operation of the pressurizing unit 3 and the HU 4 is controlled in accordance with the braking operation of the driver based on the detected braking operation. Specifically, as shown in FIG. 3, the SCS controller 5 includes a state quantity calculating section 51, a target state quantity calculating section 52, a control intervention determining section 53 as understeer determining means, and a control calculating section 54. Angstair degree determination section 55a as understeer degree determination section, vehicle speed limit determination section 55b as vehicle speed limit determination section, attitude change determination section 55c as attitude change determination section, and operation control section 56. I have.

The state quantity calculator 51 and the target state quantity calculator 52 are connected to the wheel speed sensors 6, 6,
..., The lateral G sensor 7, the yaw rate sensor 8 and the steering angle sensor 9 constitute a vehicle state detecting means.
The state quantity detection section 51 and the wheel speed sensors 6, 6,... Constitute a vehicle speed detection section, and the control calculation section 54 and the operation control section 56 constitute an attitude control section.

The state quantity calculation unit 51 turns on the vehicle in the traveling direction based on input signals from the wheel speed sensors 6, 6,..., The lateral G sensor 7, the yaw rate sensor 8, and the steering angle sensor 9. It is configured to calculate a vehicle side slip angle, a vehicle speed, and the like as a vehicle state quantity representing an attitude, and
Similarly, the target state quantity calculation unit 52 is configured to calculate a target side slip angle, a target yaw rate, and the like as a target state quantity corresponding to a vehicle state quantity converging in a target traveling direction according to a driver's driving operation. ing. Specifically, as shown in FIG. 4, the vehicle speed Vref is calculated based on each wheel speed detected by the wheel speed sensors 6, 6,.
1) The vehicle speed Vref, the wheel speeds, the lateral acceleration detected by the lateral G sensor 7, the yaw rate γ detected by the yaw rate sensor 8, and the steering angle sensor 9. The vehicle body side slip angle β is calculated based on the front wheel steering angle calculated from the detected steering angle θH (C
2).

The wheel speeds and the vehicle speed Vref
The slip rate and the slip angle of each tire 23 are calculated based on the vehicle body slip angle β, the yaw rate γ, and the front wheel steering angle (C3), and each wheel is calculated based on the wheel speed and the lateral acceleration. The vertical weight at the position is calculated (C4). Based on the vertical load, the slip ratio, and the slip angle, a load ratio, which is a ratio of the current grip force to the total grip force that each tire 23 can exert, is calculated (C
5). Further, a road surface friction coefficient between the road surface and the tires 23, 23,... Is calculated based on the load factor and the lateral acceleration (C6), and the road surface friction coefficient and the vehicle speed Vref are calculated.
Then, the target yaw rate and the target side slip angle are calculated based on the steering wheel angle and the front wheel steering angle (C7).

The control intermediary judging section 53 includes a vehicle body side slip angle deviation amount which is a deviation amount of the vehicle body side slip angle β from the target side slip angle, and a yaw rate deviation which is a deviation amount of the yaw rate γ with respect to the target yaw rate. The SCS control intervention is determined based on the calculated vehicle body slip angle deviation amount and yaw rate deviation amount.

The control arithmetic unit 54 controls the attitude of the vehicle 1 by applying a braking force to one of the right and left sides of the vehicle body 1 to apply a yaw moment around the center of gravity of the vehicle body 1 to control the attitude of the vehicle. And a deceleration control unit 5 that controls the deceleration of the vehicle by applying a braking force to both left and right sides of the vehicle body 1
4b, and a correction calculation unit 54c that changes and corrects the first determination change amount in the drift-out suppression control, and the turning posture of the vehicle follows the driving operation of the driver according to the determination result of the control intervention determination unit 53. The braking force applied to each wheel 21 is calculated so as to converge in the target traveling direction.

When the brake pressure P detected by the liquid sensor 33 becomes higher than the atmospheric pressure P0, the control operation unit 54 detects a brake operation by the driver and detects the brake operation of the pair of cut valves 32a, 32b. Of the master cylinder 10 is opened, so that the hydraulic fluid in the master cylinder 10 can flow through the first or second hydraulic line 22a, 22b in response to the brake operation of the driver. .

The understeer degree inclusion determining section 55a includes:
In the drift-out suppression control, the change in the direction of the vehicle is determined to be difficult when the tendency of the angstair is too strong, and the vehicle speed limit determining unit 55b determines the direction of the vehicle when the vehicle speed is too high. It is determined that the change is difficult. The attitude change determination unit 55c determines whether or not the vehicle south direction has changed due to the attitude control in the drift-out suppression control. The operation control section 56 operates the cut valves 32a, 32b, the pressurizing valves 41, 41, and the like according to the calculation result by the control calculation section 54.

It should be noted that the SCS controller 5
In addition to the control of S, the wheels 21FL, 21FR, 21FR,.
ABS (Ant) that limits the braking force applied to FR,.
, and a TCS (Traction Control) for limiting the driving torque of the wheels 21FR, 21FL,... to prevent slipping.
control is performed so that the ABS control is given the highest priority, and then S control is performed.
The control of the CS and the control of the TCS are arbitrated by a predetermined method.

FIG. 5 shows the overall basic control by the SCS controller 5. In this basic control, first, when the driver gets on the vehicle and turns on the ignition key, various initial settings are performed in step SA1. After the origin correction of the wheel speed sensors 6, 6,... Is performed in SA2, a signal input to the SCS controller 5 is performed from each of these sensors. Based on these signals, the vehicle speed, the vehicle deceleration, the vehicle speed at each wheel position, etc. of the vehicle traveling at step SA3 are determined by A.
It is calculated as a common vehicle state quantity for control of BS, SCS and TCS. Subsequently, at step SA4, S
Perform control calculation of CS. That is, in step SA41, the vehicle speed Vref for SCS, the vehicle side slip angle β, the wheel slip ratio and the slip angle of each wheel, the vertical load of each wheel, the tire load factor, and the road surface friction coefficient are calculated.
In, the target yaw rate, target side slip angle, and target deceleration are calculated. In step SA43, the vehicle body slip angle deviation amount and the yaw rate deviation amount are calculated on the basis of the above calculation result, and the SCS control person determination is performed based on these deviation amounts.

If it is determined that the vehicle is to be controlled, the process proceeds to step SA44 to apply wheels 21, 21,.
And the braking force applied to each of the selected wheels 21 is calculated. .. And the pressure reducing valves 43, 43,... Of each brake 2 are calculated in step SA45 based on the calculated braking force.

Further, control calculation of ABS is performed in step SA5, and control calculation of TCS is performed in step SA6.
The calculation results of the ABS, TC, and SCS are arbitrated by a predetermined method in step SA7, and the valve opening degree of each of the pressurizing valve 41 and the reduction valve 43 is determined. Then, in step SA8, each of the above-mentioned Kasho valves 4
By changing the opening degree of the pressure reducing valve 1 and the pressure reducing valve 43, a hydraulic fluid is supplied to each brake 2 in accordance with the opening degree to apply a braking force to each wheel 21. Finally, in step SA9, a fail-safe determination for detecting malfunction of the wheel speed sensors 6, 6,... Is performed, and thereafter, the process returns to step SA1.

In the above flow chart, step SA41 corresponds to the state quantity calculating section 51 and SA42 corresponds to the target state quantity calculating section 52.
43 corresponds to the control operator determination unit 53, step SA44 corresponds to the control calculation unit 54, the understeer degree inclusion determination unit 55a, the vehicle speed limit determination unit 55b, and the posture change determination unit 55c, and step SA45 corresponds to the operation control unit 56. doing.

As shown in FIG. 6, the control intervention determination of the SCS in step SA43 is performed in step SB1.
The vehicle body slip angle deviation amount x is compared with a judgment side slip angle deviation amount xl preset for SCS control man-in-the-middle determination, and the vehicle body side slip angle deviation value x is equal to or larger than the determination side slip angle deviation amount x1. In this case, it is determined that the vehicle is likely to spin due to an increase in the air steering tendency, and the process proceeds to step SB2 to perform the spinning suppression control. On the other hand, when the vehicle body side slip angle deviation amount x is smaller than the determination side slip angle deviation amount xl, the process proceeds to step SB3, and this step SB3
In step (1), the yaw rate deviation amount y is compared with a determined yaw rate deviation amount yl as a preset amount for the SCS control intervention determination. Then, when the yaw rate deviation y is equal to or larger than the determination yaw rate deviation l, it is determined that the understeer tendency of the vehicle is increasing and the vehicle is about to drift out, and step SB4 is performed.
To perform drift-out suppression control.

Next, with reference to the flowchart of FIG. 7, a description will be given of an example of control for restricting the attitude control and preventing the brake from being heavily used. Indicates a step. Also, the flowchart of FIG. 7 can be executed by interrupt processing at predetermined time intervals in the main flowchart shown in FIG. 5, or between the appropriate steps in FIG. 5, for example, steps SA45 and SA5. Can be performed as a process between the two.

First, in Q1, it is determined whether or not the flag is 0. This flag is set to 1 when the attitude control is being performed. Initially, the flag is initialized to 0, and YES is determined in Q1. At this time, it is determined in Q2 whether or not the posture control is currently being performed. If the determination in Q2 is YES,
After setting the flag to 1 in Q3, returning to Q1, Q
If the determination in Step 2 is NO, the process returns to Q1.

If the determination in Q1 is NO, it is determined in Q4 whether or not the attitude control has been completed. If the determination in Q4 is NO, in Q5, the yaw angle Y is calculated based on the yaw rate. Next, in Q6, the deviation of the yaw angle Y from the reference yaw angle (the target yaw angle) is added, and an integrated value YI that is an added value of the deviation is calculated. In Q7, it is determined whether or not the integrated value YI is larger than a predetermined value (a predetermined angle, for example, 360 degrees). If the determination in Q7 is YES, there is a high possibility that the vehicle is running in sports, and in Q8 the attitude control is stopped and the driver is fully aware that the attitude control has been stopped. A warning is issued to generate a warning sound.

If the determination in Q4 is YES, in Q9, it is determined whether or not the posture control is started again within a predetermined time. If the determination in Q9 is YES, the process proceeds to Q5, and the processing for determining whether or not the above-described posture control is stopped is performed.

If NO in Q9, after the flag is reset to 0 in Q10, in Q11,
The integrated value YI is cleared to 0, and the yaw angle deviation at Q6 is also reset to 0.

Here, as a condition for stopping the attitude control,
A condition that the lateral acceleration acting on the vehicle is equal to or more than a predetermined value may be added. In this case, for example, in Q2, it may be determined whether or not the lateral acceleration is equal to or more than a predetermined value, and if YES in this determination, the process may move to Q3.

Although the embodiment has been described above, the present invention is not limited to this, and includes, for example, the following cases. The condition for stopping the posture control may be a case where the posture control is repeatedly performed a predetermined number of times (for example, three times) within a predetermined time (for example, 20 seconds).

As a method of restricting the attitude control, the attitude control may be stopped or, for example, performed by reducing the control amount of the attitude control.
In this case, the control amount can be set to a certain constant value such as a predetermined ratio as compared with a normal case, but it is also possible to gradually reduce the control amount in a stepwise or continuously variable manner. It is possible (the attitude control amount eventually becomes zero and the attitude control can be stopped).

As another method for restricting the attitude control,
The output of the engine may be forcibly reduced to stall the vehicle (including stalling). in this case,
It can be performed completely independently of the attitude control, and is a control in the direction in which the vehicle decelerates, which is preferable from the viewpoint of safety.

Each step or various members such as a sensor and a switch shown in the flowchart can be expressed by adding a name of a means to a higher-level expression of its function. In addition, the object of the present invention is not limited to what is explicitly specified, but also implicitly includes providing what is expressed as substantially preferable or advantageous. Furthermore, the present invention can be expressed as a method.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of a vehicle that performs attitude control.

FIG. 2 is a diagram showing a brake hydraulic system of the vehicle shown in FIG. 1;

FIG. 3 is a block diagram showing a configuration example of a posture control controller.

FIG. 4 is a diagram showing the contents of processing in a state quantity calculation unit and a target state quantity calculation unit.

FIG. 5 is a flowchart showing a control example of the present invention.

FIG. 6 is a flowchart showing a control example of the present invention.

FIG. 7 is a flowchart showing a control example of the present invention.

[Description of sign]

 1: body 2: brake 3: pressurizing unit 4: haidrolic unit 5: attitude control controller 7: lateral acceleration sensor 8: yaw rate sensor 11: engine

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tetsuya Tachihata 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd.

Claims (6)

[Claims] An attitude control device for a vehicle, which controls the attitude of the vehicle by independently controlling a braking force on each wheel, wherein the attitude control is continuously performed for a predetermined time or more. An attitude control device for a vehicle, comprising a restricting means for restricting the attitude control when the attitude control is performed or a predetermined number of times or more is performed within a predetermined time. 2. A vehicle attitude control device in which a vehicle attitude control is performed by independently controlling a braking force applied to each wheel, wherein the lateral acceleration acting on the vehicle body is equal to or greater than a predetermined value. And a regulating means for regulating the attitude control when the integrated value of the yaw angle becomes equal to or larger than a predetermined angle. 3. An attitude control device for a vehicle, wherein the integrated value of the yaw angle of the vehicle is equal to or greater than a predetermined angle by controlling the attitude of the vehicle by controlling the braking force on each wheel independently. A posture control device for controlling the posture control when the vehicle is in the vehicle. 4. The vehicle attitude control device according to claim 1, wherein the restricting means stops the attitude control or reduces the control amount of the attitude control. 5. The vehicle attitude control device according to claim 1, wherein the regulating means forcibly stops the engine. 6. The vehicle attitude control device according to claim 4, wherein the restricting means generates a warning sound.