KR100552733B1 - rollover detection system for an automotive vehicles and method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an apparatus for detecting a rollover of a vehicle and a method thereof, and simultaneously detects a change in lateral acceleration, wheel speed, steering angle, etc. of a vehicle while driving, and a change in a load applied to a strut tower bar connecting a left / right shock absorber while driving. By doing so, the object of the present invention is to enable a more accurate determination of the rollover of the vehicle due to the change in the behavior posture of the vehicle body.

In order to achieve the above object, the present invention, the strut tower bar coupled to both ends between the left / right shock absorber and installed to connect between them; A strain gauge installed at a central portion of the strut tower bar to detect a change in load acting on the strut tower bar while driving; A horizontal G sensor which detects a change in the lateral acceleration of the vehicle while driving and calculates a change in the angular velocity therefrom; A steering angle detection sensor for detecting a steering angle change of the vehicle while driving; Equipped with a wheel speed sensor for detecting a change in the rotational speed of the wheel while the vehicle is running; And the rollover of the vehicle is determined from the signals input from the strain gauge, the lateral G sensor, the steering angle detection sensor, and the wheel speed sensor, respectively.

Description

Rollover detection system for vehicle and method thereof

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram schematically illustrating a correlation between roll force and lateral force acting on a tire when turning while driving;

2 is a view schematically showing the configuration of a rollover detection apparatus for a vehicle according to the present invention.

3 is a view showing an installation state of the strain gauge in the rollover detection apparatus according to the present invention.

4 is a prebody diagram for measuring the change in load acting on the strut tower bar when the rollover occurs shown in FIG.

    <Description of Symbols for Main Parts of Drawings>

10-lateral G-sensor 12-wheel speed sensor

14-steering angle sensor 16-strut tower bar

18-strain gauge 20-control section

22-Injector 24-Hydraulic Unit

Inflator 28-pretensioner drive for 26-side airbags

30-roll bar drive 32- shock absorbers

34-wheel housing 36-lower arm

38-cross member

The present invention relates to an apparatus for detecting a rollover of a vehicle and a method thereof, and more particularly, to detect a force acting on a strut tower bar installed to connect and support an upper end of a left / right shock absorber, The present invention relates to a rollover detection apparatus for a vehicle and a method thereof for more accurately determining a rollover of a vehicle in consideration of values detected from other sensors.

In general, a car passes a large number of small uneven parts of the road surface while driving on a road, and various types of shocks transmitted from the road surface to the vehicle body are mainly absorbed by springs and shock absorbers provided in the suspension system.

In this case, the spring and shock absorbers of the suspension system are unable to absorb 100% of the shock transmitted from the road surface, and as a result, the remaining shock that is not absorbed is transmitted to the vehicle body, which is felt by the driver or the passenger.

In this way, the change in the load or the amount of impact received from the road surface while the vehicle is running greatly affects the behavioral attitude of the body. In particular, when turning, the lateral force is generated and transmitted from the road surface to the tire. Indicates a change in the tilting attitude downwardly in the opposite direction to the turning.

In this case, in a vehicle with a high center of gravity from a road surface such as an SUV, a pickup, a van, and the like, which is higher than a general passenger car, a rollover situation may occur during turning.

On the other hand, in the vehicle, the roll stability can be represented by a static stability factor (SSF) value, SSF value representing this roll stability is defined as follows.

SSF = (T / 2) / H

Where T is the leap of the vehicle and H is the height relative to the center of gravity of the vehicle.

In other words, the greater the lubrication of the vehicle and the lower the center of gravity, the greater the stability of the vehicle to the roll.

In addition, the lateral force of the tire with respect to the vertical load of the tire is also closely related to the roll stability, wherein the lateral friction coefficient mu having a great influence on the lateral force of the tire is defined as follows.

μ = Fy / Fz

Here, Fy is a force acting in the lateral direction of the vehicle body, Fz is a force acting in the vertical direction of the vehicle body.

That is, the greater the lateral friction coefficient (μ), the greater the likelihood of rollover. Looking at the relationship between the two relational expressions mentioned above, it is as shown in FIG.

First, FIG. 1A illustrates a state in which roll stability of the vehicle body is lowered during turning, that is, a state in which rollover occurs.

In this case, the lateral force Fy and the vertical force Fz act simultaneously on the tire which is turning to the left side of the vehicle and located outside the turning direction, and the sum of the lateral force Fy and the vertical force Fz Ft. Is located in the inclined direction upward inward than the reference line (X) passing between the tire meets the road surface and the center of gravity of the vehicle (0) located outside the turning direction.

As a result, the moment (M) is generated in the direction opposite to the turning direction in the center of gravity (0) of the vehicle, this moment (M) is to reduce the roll stability of the vehicle has a great influence on the rollover of the vehicle. .

In contrast, FIG. 1B illustrates a state in which roll stability of the vehicle body does not decrease during turning, that is, a state in which rollover does not occur.

In this case, the lateral force Fy and the vertical force Fz act simultaneously on the tire which is turning to the left side of the vehicle and located outside the turning direction, and the sum of the lateral force Fy and the vertical force Fz Ft. Is located in the inclined direction upwardly outward from the reference line (X) passing between the tire meets the road surface and the center of gravity of the vehicle (0) located outside the turning direction.

As a result, the moment (M) is generated in the same direction as the turning direction in the center of gravity (O) of the vehicle, this moment (M) serves to prevent the rollover to play a large role in increasing the roll stability of the vehicle Will be.

In other words, the amount of lateral force (Fy) applied to tires located outside the turning direction during turning may have a great influence on roll stability.However, the larger the lubrication of the vehicle, the lower the lower the center of gravity of the vehicle. Roll stability increases as it becomes more.

Meanwhile, the SSF value, which is a measure of roll stability, is an invariant value that is determined according to the specifications of the vehicle, and the lateral friction coefficient (μ) is a variable value that is related to the tire characteristics. In order to quantify the tire characteristics, SM (stability margin) value is used, which is defined as follows.

SM = (T / 2) / H-μ

Here, if SM> 0, the force Ft vector passes above the center of gravity of the vehicle, so that the vehicle is stable to rollover;

If SM <0, the force (Ft) vector passes below the center of gravity (O) of the vehicle, so that the vehicle is unstable to rollover, i.e. there is a risk of tipping over.

That is, the SM value is a measure of the stability of the rollover in a combination state of the vehicle and the tire, and the larger the SM value is, the less the possibility that the vehicle rolls over while driving.

Therefore, conventionally, the roll stability of the vehicle is increased by detecting a rollover occurrence of the vehicle while driving in advance and preventing the rollover, so that the rollover occurrence is detected in advance as shown in the following example. There were various kinds.

First, as an example of this, there is a method of detecting the lateral acceleration and the lateral angular velocity of the vehicle while driving to determine the behavioral attitude of the vehicle using the roll angle, the roll angular velocity, and the two-dimensional setting map of the vehicle.

Secondly, when only the lateral acceleration of the vehicle is detected while driving, there is a method of detecting rollover in advance by comparing the detected lateral acceleration and the set value using the lateral acceleration sensor.

Third, there is a method of detecting the rollover of the vehicle by detecting the lateral acceleration, the lateral angular velocity, the steering angle, and the vehicle speed while driving, and calculating the roll angle of the vehicle.

Fourth, there is a method of detecting the lateral acceleration, the lateral angular velocity and the vehicle speed of the vehicle while driving, predicting the roll angle and the pitch angle of the vehicle, and the future roll angle and the pitch angle, and comparing the reference value with the reference value to detect the rollover in advance.

Fifth, the method of detecting rollover by predicting the change of the driving diameter of the vehicle by detecting the lateral acceleration, the lateral angular velocity and the number of wheel revolutions of the vehicle while driving, and then calculating the change of the behavior characteristics of the vehicle in advance. have.

Sixth, there is a method of detecting rollover in advance by detecting the lateral angular velocity of the vehicle while driving and calculating the roll angle by using the same as a physical model.

However, it is difficult to accurately detect rollovers only with the above-described series of various kinds of pre-rollover detection methods. Accordingly, despite the fact that rollovers are not actually accompanied in the future, the rollover is incorrectly predicted and the engine output is controlled. Alternatively, the braking control has a disadvantage in that the acceleration of the vehicle is impaired or the running performance is lowered.

In other words, the prior detection method for the rollover occurrence as described above was unclear in advance of the rollover occurrence, and accordingly, a series of unnecessary control (engine output control and braking control, etc.) was involved. Will be degraded.

Accordingly, the present invention has been devised in view of the above, and simultaneously detects a change in lateral acceleration, wheel speed, steering angle, etc. of a vehicle while driving, and a change in load applied to a strut tower bar connecting between a left / right shock absorber while driving. Accordingly, an object of the present invention is to provide a rollover detection method for a vehicle that enables more accurate determination of a rollover of a vehicle caused by a change in the behavior posture of a vehicle body expected from the future.

In addition, the present invention is to suppress the occurrence of the rollover by accompanying the appropriate follow-up measures, for example, output deceleration control or braking control of the engine when determining the rollover of the running vehicle through a series of processes as described above, The purpose is to minimize the deterioration of the driving performance.

The present invention for achieving the above object, the strut tower bar is coupled to both ends between the left / right shock absorbers and installed to connect between them; A strain gauge installed at a central portion of the strut tower bar to detect a change in load acting on the strut tower bar while driving; A horizontal G sensor which detects a change in the lateral acceleration of the vehicle while driving and calculates a change in the angular velocity therefrom; A steering angle detection sensor for detecting a steering angle change of the vehicle while driving; Equipped with a wheel speed sensor for detecting a change in the rotational speed of the wheel while the vehicle is running; And the rollover of the vehicle is determined from the strain gauge, the lateral G sensor, the steering angle detection sensor, and a signal input from the wheel speed sensor, respectively.

In addition, the present invention includes the steps of detecting a change in the load acting on the member connecting the vehicle body and the wheel while driving; Detecting a change in the lateral acceleration and the lateral angular velocity of the vehicle while driving; Detecting a change in steering angle while driving; Detecting a change in the number of revolutions of the wheel while driving; It is characterized by estimating a change in the behavioral attitude of the vehicle through the values detected from the above steps, and determining a rollover through this.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the present invention provides a lateral G sensor 10 for detecting a change in lateral acceleration of a vehicle while driving, a wheel speed sensor 12 for detecting a change in speed of a wheel while driving, and a steering angle during steering. The steering angle sensor 14 which detects the change and the strain gauge 18 which detects the change in the load on the strut tower bar 16 (shown in FIG. 3) connecting between the left and right shock absorbers are respectively input means. Configure.

Then, it is determined by calculating whether a future rollover occurs during driving from the lateral acceleration change detected through the input means, the wheel speed change of the wheel, the steering angle change of the steering wheel, and the load acting on the strut tower bar. In addition, when the occurrence of a rollover is foreseen in the future, the engine output is decelerated, the brakes are applied to the wheels located outside the turning direction, and an airbag (air curtain) located on the side of the cabin in preparation for overturning is provided. Control the restraint of the driver's body to the seat by increasing the tension of the seat belt, and deploying the roll bar (provided to protrude to the side of the vehicle body in case of overturning). The control unit 20 is configured to control the control means.

In addition, the injector 22 for controlling the output of the engine by adjusting the amount of fuel injected into the combustion chamber under the control of the control unit 20, and the hydronic unit for controlling the braking pressure for the wheel located in the outer side of the turning direction (24), the inflator 26 for side airbags for controlling the deployment of airbags located on the side of the vehicle interior, the pretensioner drive unit 28 for adjusting the tension of the seat belt provided in the seat, and the roll for adjusting the operation of the roll bar. The bar driver 30 is configured as an output means, respectively.

Here, the lateral G sensor 10 is individually installed in at least one axis of the vehicle, for example, in the X, Y, and Z axis directions of the vehicle body to detect changes in acceleration in the X, Y, and Z axis directions, respectively. Preferably, the wheel speed sensor 12 is installed on each wheel individually, and the steering angle sensor 14 is provided in a steering column (not shown above) to which a steering wheel is mounted.

In addition, the strain gauge 18 installed in the strut tower bar 16 has a strut tower bar 16 installed between the upper end portions of the shock absorbers 32 provided in the left and right wheels, as shown in FIG. In the middle of the strut tower bar 16, the strain gauge 18 is provided.

In addition, the upper end of the shock absorber 32 is fixed to the vehicle body side wheel housing 34, the lower end of the shock absorber 32 is fixed to one end of the lower arm 36, the lower arm 36 The other front end portion is fixed to the vehicle body side cross member 38.

Here, the strut tower bar 16 serves to reduce the distortion of the vehicle body during driving and to suppress the movement of the shock absorber 32 in the vertical and horizontal directions to keep the vehicle body in the correct position. 16 is adopted to increase the rigidity of the vehicle body to suppress the movement of the shock absorber 32 during driving, to reduce the change of the finely moving camber, and to suppress the deformation of the engine compartment during side impact.

On the other hand, in the present invention in the pre-determination of the rollover of the vehicle while driving, the strain gauge 18 adopted as one of the important measures to detect the change in the load acting on the strut tower bar 16 while driving, the details The process is as follows.

That is, as shown in the prebody diagram of FIG. 4, the thrust force corresponding to the lateral force generated at the contact portion between the tire and the road surface centered on the connection point between the shock absorber 32 and the lower arm 36. The first load F1, the second load F2 corresponding to the reaction force acting as a connection point between the shock absorber 32 and the lower arm 36, and the strut tower bar 16 and the shock absorber ( Of the load acting on the strut tower bar 16 through a moment equilibrium relationship to the third load F3 corresponding to the reaction force acting towards the strut tower bar 16 at the point of connection between the upper ends of The change can be estimated.

For example, as shown in FIG. 4, the strut tower bar 16 and 으로부터 from zero horizontal sum and moment sums for loads acting on each point when the vehicle turns to the right. By calculating the third load F3, which is a reaction force acting at the point connecting the upper ends of the absorber 32, it can be seen that the tension state.

This can be seen from the following assumptions.

First, the distance L1 between the upper end of the shock absorber 32 and the strut tower bar 16 and the lower end of the shock absorber 32 and the lower arm 36 is set to 900 mm. , L2, which is the distance between the lower end of the shock absorber 32 and the road surface, is set to 300 mm, and the load of the wheel is set to 1500 kgf.

And, it is assumed that the load movement of the vehicle body is made 100% to the outside of the turning direction during the sharp turning.

In addition, it is assumed that the vehicle is in the turning state of 1G during the sharp turning.

Based on these assumptions, a third load is obtained from the relationship of moment equilibrium at the connection point between the lower end of the shock absorber 32 and the lower arm 36 (ΣM = 0; F1 * L2 = F3 * L1). When calculating (F3), it can be seen that the third load (F3) is 500kgf.

That is, during rapid turning in the 1G state with 100% load movement, a tensile force of 500 kgf is applied to the turning outer portion of the strut tower bar 16.

At this time, since the wheel inside the swing is spaced apart from the road surface, no load acts on the swing inner portion of the strut tower bar 16.

From this, it can be seen that a large tensile force acts on the strut tower bar 16 during a sharp turn to generate a rollover.

On the other hand, when one wheel passes the protrusion of the road surface while driving, a compressive force acts on the strut tower bar 16, which can also be verified through the prebody diagram shown in FIG.

Accordingly, the controller 20 detects the change in the lateral acceleration, the change in the wheel speed, and the change in the steering angle, respectively, via the lateral G sensor 10, the wheel speed sensor 12, and the steering angle sensor 14 while driving. By detecting the change in the load acting on the strut tower bar 16 via the strain gauge 18, it is possible to accurately predict the future rollover from this.

In addition, the control unit 20 controls the output reduction of the engine through the injector 22 and the wheels located outside the turning direction through the hydronic unit 24, when the rollover is expected to occur in the future. Braking control, operation control of the airbag in case of overturning through the inflator 26 for the side airbag, tension control of the seat belt through the pretensioner driving unit 28, and overturning through the roll bar driving unit 30. It becomes possible to perform drive control of the roll bar in preparation for the city.

As described above, according to the rollover detection apparatus and method thereof of the vehicle according to the present invention, the rollover phenomenon generated from the change of the vehicle's attitude during driving is detected by the existing sensors and the strut tower bar 16. By considering the information on the change in load acting on the strut tower bar 16 via the installed strain gauge 18 as a whole, it becomes possible to make a more accurate prediction of the future rollover.

In addition, it is possible to prevent unnecessary deterioration of the acceleration or the running of the vehicle through the implementation of the output control, braking control, etc. of the engine through the accurate prediction of the future rollover as described above.

In addition, through the application of the strut tower bar 16 there is an effect that can increase the rigidity of the vehicle body.

Claims (5)

A strut tower bar coupled to both ends between the left / right shock absorbers and connected to each other; A strain gauge installed at a central portion of the strut tower bar to detect a change in load acting on the strut tower bar while driving; A horizontal G sensor which detects a change in the lateral acceleration of the vehicle while driving and calculates a change in the angular velocity therefrom; A steering angle detection sensor for detecting a steering angle change of the vehicle while driving; Equipped with a wheel speed sensor for detecting a change in the rotational speed of the wheel while the vehicle is running; And the rollover of the vehicle is determined from the strain gauge, the lateral G sensor, the steering angle detection sensor, and the signals input from the wheel speed sensor. Detecting a change in the load acting between the vehicle body and the wheel while driving by means of a strain gauge installed at the strut tower bar connecting between the upper ends of the left / right shock absorbers; Detecting a change in the lateral acceleration and the lateral angular velocity of the vehicle while driving; Detecting a change in steering angle while driving; Detecting a change in the number of revolutions of the wheel while driving; Rollover detection method of a vehicle characterized in that it is expected to change the behavioral attitude of the vehicle through the value detected from the steps, thereby determining the rollover. delete The method of claim 2, Detecting the change in the lateral acceleration and the angular velocity of the vehicle by means of a lateral G sensor installed in at least one axis of the vehicle. The method of claim 2, In predicting the rollover of the vehicle from the above step, the rollover determination of the vehicle is characterized in that the change in the load acting on the strut tower bar is in a tension state.

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