JPH11254992A - Vehicle rolling tendency determining device and rolling preventing device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle rolling tendency determining device which can precisely determine a rolling tendency of a vehicle at a low cost, and a rolling preventing device using the same. SOLUTION: A rolling tendency determining device 3 detects occurrence of racing of a drive wheel inside of a turn, in view of variation in speeds of left and right drive wheels during an abrupt turn of a vehicle, and accordingly, it is determined that the vehicle has a rolling tendency at the drive wheel inside of the turn in view of the racing tendency, and accordingly, the rolling tendency can be precisely determined, irrespective of a loading weight, a number of occupants and a kind of a vehicle. Further, a rolling preventing device 12 lowers the output of an engine or actuates a brake device 11 so as to restrain the rolling from being advancing, in order to prevent the vehicle from rolling in view of a stable determination result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rollover tendency judging device for judging whether or not a turning state of a vehicle tends to rollover, and a rollover prevention device using the device.

[0002]

2. Description of the Related Art It is known that an automobile (vehicle) bends outward due to centrifugal force when turning. For this reason, when a sharp turning operation is performed and the force that causes the vehicle to lean outward exceeds the ground contact force, the wheels (driven wheels / drive wheels) inside the turning lift up from the road surface and roll over.

In particular, vehicles having a high center of gravity, or vehicles such as trucks and buses whose center of gravity varies greatly depending on the load and the number of occupants have a low turning limit. Therefore, Japanese Patent Laid-Open No. 6-31
No. 2612 discloses a combination of a lateral acceleration sensor for detecting a lateral acceleration of a vehicle and a load sensor for detecting a contact load of each wheel, or a combination of the lateral acceleration sensor and a vehicle height sensor for detecting a vehicle height of each wheel. It is determined that there is a danger of rollover when the lateral acceleration is equal to or more than a predetermined value and the contact load of at least one wheel is equal to or less than a predetermined value.
Alternatively, when the lateral acceleration is equal to or more than a predetermined value and the vehicle height of at least one wheel is equal to or more than the predetermined value, it is determined that there is a danger of rollover, and preparations for rollover prevention are performed.

[0004]

However, in recent years when low cost is desired, it is required that a stable judgment can be made at a low cost even when there is a danger of rollover. However, in the former determination structure for detecting the grounding load, it is necessary to use an expensive load sensor which is not widely used. In addition, the cost of mounting the load sensor is considerably increased due to an increase in the scale of the modification on the vehicle side, such as by changing a part of the suspension, for the purpose of detecting the grounding load.

In the latter structure for detecting the vehicle height, since the vehicle height varies depending on the loaded state of the vehicle and the number of occupants, it is difficult to appropriately set a threshold value for determining the danger of rollover. However, the accuracy of the determination is poor, so that an appropriate determination may not be performed.

[0006] For this reason, there is a demand for a judging device in consideration of cost and judgment accuracy. The present invention has been made in view of the above circumstances, and its object is to provide a vehicle rollover tendency determination device and a rollover prevention device using the device that can determine the vehicle rollover tendency with high accuracy at low cost. To provide.

[0007]

According to a first aspect of the present invention, there is provided an apparatus for judging the tendency of a vehicle to roll over according to the first aspect of the present invention. The system adopts a method of detecting that a slip tendency has occurred in the drive wheels of the vehicle and judging that the vehicle has a tendency to roll over based on the slip tendency. Before the rollover, it is determined that there is a tendency to roll over.

[0008] When such wheel speed detection is used, a stable detection output can always be expected irrespective of the loaded load, the number of occupants, and the type of vehicle, so that the rollover tendency of the vehicle can be determined with high accuracy.

In addition, the detection system for detecting the wheel speed does not require a special sensor, is easy to mount on the vehicle side, and is inexpensive, so that the cost is low. According to a second aspect of the present invention, the vehicle rollover prevention device further includes a safety measure execution unit for taking a safety measure for preventing the vehicle from rolling over in the configuration according to the first aspect, and the vehicle rollover prevention device is provided based on the tendency of the drive wheels to idle. When the vehicle has a tendency to roll over, the progress of the rollover is suppressed to prevent the vehicle from rolling over.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIGS. In FIG. 1, reference numeral 1 denotes a driving engine, for example, a diesel engine 2,
An automobile (vehicle) 3 having a front wheel as a driven wheel and a rear wheel as a driving wheel, and 3 denotes a rollover tendency determination device mounted on the automobile 1.

The rollover tendency determining device 3 includes a controller 4 (determining means,
Control means). A detection system for detecting the wheel speed of each wheel of the automobile 1 is connected to the controller 4. Specifically, a wheel speed sensor 6 for detecting a wheel speed of a left driven wheel (front left wheel) of the automobile, a wheel speed sensor 7 for detecting a wheel speed of a right driven wheel (front right wheel), and a left driving wheel (left side) A wheel speed sensor 8 (corresponding to the wheel speed detecting means of the present application) for detecting the wheel speed of the rear wheel, and a wheel speed sensor 9 (a wheel speed detecting means of the present application) for detecting the wheel speed of the right driving wheel (right rear wheel). Is connected).

The controller 4 is connected to a lateral acceleration sensor 10 (corresponding to a turning state detecting means of the present invention) for detecting a lateral acceleration acting on the vehicle body 1a so that the turning state of the automobile can be detected. is there.

The controller 4 determines from the detection outputs of the wheel speed sensors 5 to 6 and the lateral acceleration sensor 20 whether or not the vehicle has a tendency to roll over when turning.

That is, the controller 4 has a function of determining whether or not a sharp turn causing rollover has been performed. The vehicle speed is not less than a predetermined vehicle speed, for example, 15 km / h or more, and at this time, the lateral acceleration is not less than a predetermined value. A function to determine the time has been set. Further, the controller 4 has two functions, for example, a function of determining whether or not there is a tendency for the drive wheel (rear wheel) to idle at the turning inner wheel, which is a sign of the start of rollover. A function that determines whether or not the inner wheel in the turning direction has a tendency to idle based on a comparison between the wheel speed and the wheel speed of the outer wheel in the turning direction, and also causes a tendency to idle in the inner wheel in the turning direction from the wheel acceleration of the inner wheel in the turning direction of the driving wheel. And a function of determining whether or not the operation has been performed.

That is, the controller 4 detects the tendency of the inner wheel of the drive wheel to turn in the turning direction during the sharp turn, and detects the tendency of the inner wheel to take off before the vehicle rolls over, that is, the tendency of the inner wheel to take off during the process of the vehicle rolling over. It can be determined whether or not the vehicle has a tendency to roll over.

The controller 4 includes means for taking safety measures such as deceleration means, specifically, the electronic governor 2a of the diesel engine 2 and the automatic brake device 11
(Both correspond to safety measure execution means) are connected, and constitute a rollover prevention device 12 using the rollover tendency determination device 3.

That is, the controller 4 has a function of controlling the electronic governor 2a so as to decrease the output of the diesel engine 2, for example, when a rollover tendency is detected, and also operates the automatic brake device 11 to decrease the vehicle speed of the automobile. Function is set, and when the car turns sharply,
When a sign of rollover occurs, the vehicle is automatically decelerated to reduce the lateral acceleration of the vehicle that causes rollover.

The operation of the rollover tendency judging device 3 and the rollover prevention device 12 is shown in the flowchart of FIG.
Next, the operation will be described with reference to this flowchart. It is assumed that the car 1 is running on the road now.

In step S1, the controller 4 determines the wheel speeds VFL, VER, VRL, of the wheels (the left and right wheels of the driven wheels (front wheels) / the left and right wheels of the driving wheels (rear wheels)) from the wheel speed sensors 6 to 9 in step S1.
VRR is read, the lateral acceleration Gy is read from the lateral acceleration sensor 10, and in the following step S2, the wheel speed VF of the driven wheel
The vehicle speed V is calculated from L and VFR, and in the following step S3, the wheel acceleration GR of the left and right drive wheels is calculated from the wheel speeds VRL and VRR of the drive wheels.
L and GRR are calculated.

Further, the controller 4 monitors in step S4 whether or not the vehicle speed V is a vehicle speed at which rollover may occur with a sharp turn, and in a succeeding step S5, a large lateral acceleration Gy generated by the sharp turn is applied to the vehicle body. It monitors whether it is working.

At this time, for example, the car 1 is 70 km, for example.
Suppose you make a sharp turn by operating the steering wheel while driving at / h.
Then, the controller 4 detects a predetermined value from the output of the lateral acceleration sensor 10 in step S5, that is, a lateral acceleration exceeding a threshold value which determines whether or not the vehicle makes a sharp turn, and determines that the sharp turn has been performed. After the turning direction is determined from the direction in which the lateral acceleration acts in S6, it is determined whether or not the vehicle is likely to roll over based on the comparison of the wheel speeds of the left and right driving wheels.

At this time, if the sudden steering operation is, for example, a sharp leftward turning operation, the process proceeds to step S8 to determine whether or not the wheel speed of the inner wheel in the turning direction of the drive wheel is higher than that of the outer wheel in the turning direction. Steps S8 to S9
The process proceeds to a determination as to whether or not the wheel acceleration GRL of the turning inner wheel of the drive wheel indicated by よ り 大 き い is greater than a predetermined value.

Here, when the vehicle rolls over suddenly, as shown by a two-dot chain line in FIG. 1, the inner wheel in the direction of rotation rises due to the centrifugal force at the time of turning, and the vehicle body rolls outward in the direction of rotation. Proceed in the order of ぷ.

The tendency of the turning inner wheel to take off in this rolling process depends on the magnitude of the generated lateral acceleration and the direction of the occurrence of the lateral acceleration, and the like. It can be seen that the turning inner wheel takes off and spins off.

The tendency of the vehicle to roll over when the turning inner wheel tends to spin while contacting the ground is accurately determined by determining whether or not the wheel speed of the inner wheel in the turning direction is higher than the outer wheel in the turning direction shown in step S8. Is detected. Incidentally, when the vehicle turns, the wheel speed of the turning outer wheel is normally higher than the wheel speed of the turning inner wheel due to the relationship between the inner wheels, and if it is detected that the relationship is reversed as described above, the idling of the turning inner wheel is determined. The tendency can be detected appropriately. The means for determining the idling tendency due to the wheel speed is not limited to the above. For example, the idling tendency of the turning inner wheel is determined by comparing a wheel speed difference between the turning inner wheel and the turning outer wheel of the left and right driving wheels with a predetermined value. You may do it.

Immediately, the rollover tendency when the turning inner wheel takes off and starts to spin can be accurately detected by determining whether or not the acceleration of the turning inner wheel is greater than a predetermined value in step S9. In this case, even if the wheel speed of the inner wheel in the turning direction is lower than that of the outer wheel in the turning direction, it is possible to detect the occurrence of the idling tendency with good responsiveness.

Thus, at the beginning of the process leading to rollover during turning, it is detected that the turning inner wheel has a tendency to take off. As described above, since the takeoff tendency is detected based on the wheel speed, a stable determination can always be expected regardless of the loaded weight, the number of occupants, and the type of vehicle, and the vehicle is determined to have a tendency to roll over with high accuracy. Can be performed.

In addition, the detection of wheel speed does not use a special sensor and uses the inexpensive wheel speed sensors 6 to 9 which are usually used for controlling an automobile and are inexpensive as a detection system. It is also cheap.

It should be noted that even if the vehicle makes a sharp right turn, step S
Needless to say, it is possible to determine with high accuracy that the vehicle has a tendency to roll over by the same method (steps S11 and S12) as in steps 8 and S9.

On the other hand, steps S8, S9, S11, S
If it is determined in step 12 that the inner wheel in the turning direction has a tendency to take off, the process proceeds to step S13, in which the controller 4 controls the electronic governor 2a so as to reduce the engine output, and takes a safety measure of activating the automatic brake device 11. Taken.

As a result, the vehicle automatically decelerates and the lateral acceleration that causes rollover is reduced, and the rollover thereafter is suppressed. Therefore, the vehicle body that is about to roll over returns, and subsequently, the grounding force of the turning inner wheel is restored, so that the rollover can be prevented beforehand. In addition, since the wheel speed of the drive wheel is detected to prevent the rollover, a stable and reliable safety measure can always be expected.

In the embodiment, the lateral acceleration is detected by the lateral acceleration sensor. However, the present invention is not limited to this. For example, the lateral acceleration may be obtained by calculating from the vehicle speed and the steering wheel angle. Further, the determination of the turning direction uses the lateral acceleration, but is not limited thereto, and may be performed based on the output of the steering wheel angle sensor.

The determination of a sharp turn is based on the lateral acceleration. However, the present invention is not limited to this, and the determination may be made by comparing the steering wheel angle or the steering wheel angular speed with a reference value that decreases in accordance with the vehicle speed.

Although the deceleration means for reducing the engine output and activating the automatic brake device is used as the safety measure executing means, these may be used alone or not limited to this, and may be applied to the control between a plurality of wheels. The yaw control by controlling the power difference or the driving force difference, the control of the rear wheel steering, the roll control, or a structure combining a plurality of these may be used. Needless to say, an alert for notifying the rollover tendency may be combined.

In the above-described embodiment, the electronic governor of the diesel engine is controlled to reduce the engine output. However, the mechanical governor may be controlled, or the fuel injection amount, the intake amount, the ignition amount of the gasoline engine may be controlled. The timing may be controlled.

[0036]

As described above, according to the rollover tendency judging device according to the first aspect, it is detected that the drive wheel on the turning inner wheel side has a tendency to take off based on the wheel speed of the drive wheel. Is determined to have a tendency to roll over, so the load weight, number of occupants,
Regardless of the type of vehicle, a stable rollover tendency can always be determined with high accuracy.

In addition, the detection system for detecting the wheel speed does not require a special sensor, is easily mounted on the vehicle side, and is inexpensive, so that it is inexpensive.
According to the rollover prevention device of the second aspect, in addition to the effect of the first aspect, when the vehicle is in a rollover tendency, safety measures for preventing the rollover of the vehicle are taken to suppress the progress of the rollover, and the rollover of the vehicle is suppressed. Can be prevented beforehand. Moreover, since safety measures are taken based on the detection results of the wheel speeds of the drive wheels, stable and reliable rollover prevention performance can be expected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a rollover tendency determination device and a rollover prevention device using the device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of rollover determination and an operation of rollover prevention of each device.

[Explanation of symbols]

4 Controller (determination means, control means) 2a, 11 ... Electronic governor, automatic braking device (safety measure execution means) 8, 9 ... Wheel speed sensor (wheel speed detection means) 10 ... Lateral acceleration sensor (turning state detection means) .

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kunio Sakata 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation

Claims (2)

[Claims] A turning state detecting means for detecting a turning state of the vehicle; a wheel speed detecting means for detecting wheel speeds of left and right drive wheels, respectively; a detection output of the turning state detecting means being equal to or higher than a predetermined turning state. Determination means for determining that the vehicle has a tendency to roll over by detecting that an idle tendency has occurred in the drive wheel on the turning inner wheel side based on the detection output of the wheel speed detection means. apparatus. 2. A turning state detecting means for detecting a turning state of the vehicle, a wheel speed detecting means for detecting wheel speeds of left and right driving wheels, respectively, and a safety measure for taking safety measures for preventing the vehicle from rolling over. Means for executing the safety measure when it is detected that the driving wheel on the turning inner wheel side has an idling tendency based on the detection output of the wheel speed detecting means when the detection output of the turning state detection means is equal to or more than a predetermined turning state. And a control means for activating the means.