KR102512466B1 - Vehicle and control method for the same - Google Patents

Abstract

In the event of a rollover accompanied by lateral motion, the possibility of rollover is determined by reflecting the rotational kinetic energy due to the lateral force and airbag deployment is determined, thereby improving the reliability of the result of determining the possibility of rollover and enabling the airbag to be deployed quickly before a rollover occurs. It provides a vehicle and its control method.
A vehicle according to an embodiment includes an airbag module that includes at least one airbag and deploys the airbag when a trigger signal is input; Motion state detection unit for detecting roll rate, lateral acceleration and wheel speed of the vehicle; And obtaining rotational kinetic energy in the roll direction of the vehicle using the detected roll rate and the detected lateral acceleration, and using an effective center of gravity height that varies depending on a rollover environment and rotational kinetic energy in the roll direction It includes; a control unit for determining the possibility of overturning of the vehicle.

Description

Vehicle and its control method {VEHICLE AND CONTROL METHOD FOR THE SAME}

The disclosed invention relates to a vehicle capable of predicting a vehicle rollover and a control method thereof.

An airbag is installed in a vehicle to prevent a collision between an occupant and a structure within the vehicle and reduce transmission of an impact applied to the vehicle to the occupant in the event of an accident.

A controller that determines whether an airbag deploys determines an airbag deployment condition based on output values of various sensors indicating a vehicle state, and transmits a deployment signal to an airbag module when the airbag deployment condition is satisfied.

For example, when a vehicle collision is predicted or a vehicle rollover is predicted, the airbag deployment condition may be satisfied.

Reliability of the result of determining the possibility of rollover by determining the possibility of rollover and determining the airbag deployment by reflecting the rotational kinetic energy from lateral force in the event of a rollover accompanied by lateral motion and the height of the effective center of gravity, which varies depending on the type of road surface or obstacle in the event of a tripped rollover A vehicle capable of rapidly deploying an airbag before rollover occurs and a control method thereof are provided.

A vehicle according to an embodiment includes an airbag module that includes at least one airbag and deploys the airbag when a trigger signal is input; Motion state detection unit for detecting roll rate, lateral acceleration and wheel speed of the vehicle; And obtaining rotational kinetic energy in the roll direction of the vehicle using the detected roll rate and the detected lateral acceleration, and using an effective center of gravity height that varies depending on a rollover environment and rotational kinetic energy in the roll direction It includes; a control unit for determining the possibility of overturning of the vehicle.

The control unit may integrate a difference between the reference lateral acceleration and the lateral acceleration detected by the movement state detector, and obtain rotational kinetic energy in the roll direction using the integrated difference.

The reference lateral acceleration may represent the magnitude of the inertial lateral acceleration that causes roll overturn by exceeding the gravitational acceleration that prevents roll overturn at a certain roll angle.

The control unit may obtain the effective center of gravity height by using a ratio of an increase in roll angle of the vehicle and a decrease in lateral speed of the vehicle.

The control unit may obtain a factor representing the possibility of overturning the vehicle according to the height of the effective center of gravity, and determine the possibility of overturning the vehicle using the obtained factor.

The control unit calculates a roll overturn index value using rotational kinetic energy of the vehicle in the roll direction, the height of the effective center of gravity, and the minimum potential energy for roll over of the vehicle, and the calculated roll over index value is determined in advance. When the set reference value is exceeded, it may be determined that there is a possibility of overturning of the vehicle.

If it is determined that there is a possibility of the vehicle overturning, the control unit may transmit a trigger signal for airbag deployment to the airbag module.

The control unit may calculate the roll overturn index value when a pre-set overturn possibility determination condition is satisfied.

The condition for determining the possibility of rollover is that the magnitude of the vehicle's lateral acceleration exceeds a first reference value, that the vehicle's lateral velocity and the vehicle's lateral acceleration have opposite signs, and the direction in which the roll angle of the vehicle increases and the direction in which the lateral speed of the vehicle increases is the same, the roll angle of the vehicle exceeds the second reference value, and the lateral speed of the vehicle exceeds the third reference value. there is.

The movement state sensor may include a roll rate sensor, a lateral acceleration sensor, and a wheel speed sensor.

A vehicle control method according to an embodiment includes detecting a vehicle roll rate, lateral acceleration, and wheel speed; obtaining rotational kinetic energy of the vehicle in a roll direction using the detected roll rate and the detected lateral acceleration; determining a rollover possibility of the vehicle using an effective center of gravity height that varies depending on a rollover environment and rotational kinetic energy in the roll direction; Transmitting a trigger signal to an airbag module when it is determined that there is a possibility of overturning of the vehicle.

Obtaining rotational kinetic energy of the vehicle in the roll direction may include integrating the difference between the reference lateral acceleration and the lateral acceleration detected by the motion state sensor, and obtaining the rotational kinetic energy in the roll direction using the integrated difference. can

The reference lateral acceleration may represent the magnitude of the inertial lateral acceleration that causes roll overturn by exceeding the gravitational acceleration that prevents roll overturn at a certain roll angle.

The method may further include obtaining the effective center of gravity height by using a ratio of an increase in roll angle of the vehicle and a decrease in lateral speed of the vehicle.

The vehicle control method further includes acquiring a factor indicating a possibility of overturning the vehicle according to the height of the effective center of gravity, and determining the possibility of overturning the vehicle by using the obtained factor. Determining the possibility of overturning; may include.

Determining the possibility of rollover of the vehicle is to calculate a rollover index value using rotational kinetic energy of the vehicle in the roll direction, the height of the effective center of gravity, and the minimum potential energy for rollover of the vehicle, and the calculated Determining that there is a possibility of overturning the vehicle when the rollover index value exceeds a preset reference value; may include.

The vehicle control method further includes determining whether or not a preset rollover possibility determination condition is satisfied; The rollover index value may be calculated when the overturnability determination condition is satisfied.

The condition for determining the possibility of rollover is that the magnitude of the vehicle's lateral acceleration exceeds a first reference value, that the vehicle's lateral velocity and the vehicle's lateral acceleration have opposite signs, and the direction in which the roll angle of the vehicle increases and the direction in which the lateral speed of the vehicle increases is the same, the roll angle of the vehicle exceeds the second reference value, and the lateral speed of the vehicle exceeds the third reference value. there is.

According to a vehicle and a control method thereof according to an embodiment, when overturning accompanied by lateral motion, the possibility of rollover is determined by reflecting rotational kinetic energy due to lateral force and airbag deployment is determined, thereby improving the reliability of the result of determining the possibility of rollover, , the airbag can be deployed quickly before a rollover occurs.

1 is an external view of a vehicle according to an exemplary embodiment.
2 is a control block diagram of a vehicle according to an exemplary embodiment.
3 is a diagram showing a configuration related to an airbag of a vehicle according to an embodiment.
4 is a control block diagram of a vehicle in which the configuration of the movement state sensing unit is embodied.
5 is a diagram for showing rotational kinetic energy in a roll direction generated by a lateral force.
6 and 7 are diagrams illustrating an effective center of gravity height when the vehicle is caught and overturned.
8 to 10 are graphs showing roll angles and lateral speeds measured in various environments.
11 is a graph showing SF values according to the height of the effective center of gravity of the vehicle.
12 is a graph showing changes in lateral velocity estimation gain according to the centripetal force of the vehicle.
13 is a graph showing test results obtained by measuring a point in time at which the possibility of a vehicle rollover is determined according to an exemplary embodiment.
14 is a flowchart of a method for controlling a vehicle according to an exemplary embodiment.

Like reference numbers designate like elements throughout the specification. This specification does not describe all elements of the embodiments, and general content or overlapping content between the embodiments in the technical field to which the present invention belongs is omitted.

Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case of being directly connected but also the case of being indirectly connected, and indirect connection includes being connected through a wireless communication network. do.

In addition, when a certain component is said to "include", this means that it may further include other components without excluding other components unless otherwise stated.

Expressions in the singular number include plural expressions unless the context clearly dictates otherwise.

In addition, terms such as "~ unit", "~ group", "~ block", "~ member", and "~ module" may mean a unit that processes at least one function or operation. For example, the terms may mean at least one hardware such as a field-programmable gate array (FPGA)/application specific integrated circuit (ASIC), at least one software stored in a memory, or at least one process processed by a processor. there is.

The codes attached to each step are used to identify each step, and these codes do not indicate the order of each step, and each step is performed in a different order from the specified order unless a specific order is clearly stated in the context. It can be.

Hereinafter, embodiments of a vehicle and a control method thereof will be described in detail with reference to the accompanying drawings.

1 is an external view of a vehicle according to an embodiment, FIG. 2 is a control block diagram of a vehicle according to an embodiment, and FIG. 3 is a diagram showing a configuration related to an airbag of a vehicle according to an embodiment.

Referring to FIG. 1 , a vehicle 100 according to an embodiment includes wheels 51 and 52 for moving the vehicle 100, a door 71 for shielding the inside of the vehicle 100 from the outside, and a vehicle 100 for a driver. ) a windshield 63 providing a forward view, and side mirrors 81L and 81R providing a driver a view of the rear side of the vehicle 100.

In addition, the driving device 60 provided inside the vehicle 100 provides rotational force to the front wheels 51 or the rear wheels 52 so that the vehicle 100 moves.

When the vehicle 100 is a front wheel drive type, the driving device 60 provides rotational force to the front wheels 51, and provides rotational force to the rear wheels 52 when the vehicle 100 is a rear wheel drive type. In addition, when the vehicle 100 is a four-wheel drive type, rotational force may be provided to both the front wheels 51 and the rear wheels 52 .

Such a drive device 60 may employ an engine that generates rotational force by burning fossil fuel or a motor that generates rotational force by receiving power supplied from a capacitor, and may employ a hybrid method in which both the engine and the motor are provided and used selectively. Recruitment is also possible.

In addition, the vehicle 100 includes a proximity sensor for detecting obstacles or other vehicles around the vehicle, a rain sensor for detecting whether or not there is precipitation and the amount of precipitation, an RPM sensor for detecting RPM, and a position sensor for detecting the current location of the vehicle by receiving a GPS signal. , and may include a sensing device such as a speed sensor that detects the motion state of the vehicle. Sensors for detecting the motion state of the vehicle will be described again later.

Referring to FIGS. 2 and 3 together, the vehicle 100 determines the possibility of overturning of the vehicle based on the output of the movement state detector 110 that detects the movement state of the vehicle 100, and , a controller 120 that determines whether to deploy an airbag based on a result of determining the possibility of a vehicle rollover, and an airbag module 130 that deploys an airbag when an airbag deployment trigger signal is input from the controller 120.

The airbag module 130 may include a driver's seat airbag 131 mounted on a steering wheel of a driver's seat, a passenger seat airbag 132 mounted on a dashboard, and a curtain airbag 133 mounted on a roof rail of the vehicle 100. . In addition, it is possible to further provide a side airbag mounted on the door separately from the curtain airbag 133 .

The airbag module 130 may further include an inflator generating gas to be injected into the airbags 131 , 132 , and 133 . The powder ignition type inflator may include an ignition circuit, an ignition agent, a gas generator, a gas filter, and the like. When current flows through the ignition circuit, the gunpowder is combusted, and when the ignition agent is burned by the combustion of the gunpowder, heat is generated and the gas generating agent is combusted. Nitrogen gas is rapidly generated by combustion of the gas generating agent, foreign substances are removed from the nitrogen gas while passing through a gas filter, and the nitrogen gas may be introduced into the airbag in a reduced temperature state.

The airbags 131, 132, and 133 may be made of nylon, and after being inflated by the nitrogen gas introduced from the inflator, nitrogen gas is discharged through the discharge hole again to prevent the occupant from being compressed by the airbag.

Since the aforementioned structure of the airbag module 130 is only an example that can be applied to the vehicle 100, other structures other than the above structure can be applied, of course.

The control unit 120 controls a plurality of airbags 131, 132, and 133 included in the airbag module 130 based on the type of event such as rollover or impact that has occurred or is expected to occur in the vehicle 100. ) to determine which airbag to deploy.

For example, if it is predicted that the vehicle 100 will roll over in the driver's seat direction, the controller 120 can deploy the curtain airbag 133 provided on the driver's seat side, and the vehicle 100 rolls over in the passenger seat direction. If predicted, the controller 120 may deploy the curtain airbag 133 provided on the passenger seat side.

Also, the controller 120 may deploy the airbag 130 even when a collision of the vehicle 100 is detected. To this end, at least one collision sensor may be installed in the vehicle 100 to detect an impact applied to the vehicle 100 and output impact amount data.

For example, the crash sensors may include a frontal crash sensor 141 mounted on the front of the vehicle 100 and a side crash sensor 142 mounted on the side of the vehicle 100 . The frontal collision sensors 141 may be mounted on the driver's seat side and the passenger seat side, respectively, and the side collision sensors 142 may also be mounted on the left and right sides, respectively.

Data output from the movement state detector 110 or the collision sensors 141 and 142 may be transmitted to the control unit 120 through a communication protocol inside the vehicle 100 .

As a communication protocol inside the vehicle 100, CAN (Controller Area Network), LIN (Local Interconnection Network), MOST (Media Oriented Systems Transport), FlexRay, Ethernet, and the like can be used.

For example, a plurality of electronic control units (ECUs) may transmit a CAN signal to one CAN bus or request a necessary CAN signal. Here, each ECU may serve as a node in CAN communication, and the CAN signal may be transmitted in the form of a message.

Data output from the motion state sensor 110 or the collision sensors 141 and 142 may be transmitted to the control unit 120 through the CAN bus, and the trigger signal for airbag deployment output from the control unit 120 may be transmitted through the CAN bus It can be delivered to the airbag module 130 through.

However, the communication method of the vehicle 100 is not limited to the above method, and it is possible to use a communication protocol other than CAN, or to communicate with only some of the components through CAN and use other communication protocols for the rest. do.

For example, it is also possible to use PSI5 (Peripheral Sensor Interface 5) for communication between the motion state detector 110 and the collision sensors 141 and 142 and the control unit 120 .

Also, a hardwired interface may be used.

4 is a control block diagram of a vehicle in which the configuration of the movement state sensing unit is embodied.

4, the movement state sensor 110 includes a roll rate sensor 111, a yaw rate sensor 112, a longitudinal acceleration sensor 113, a lateral acceleration sensor 114, and a wheel speed sensor 115 can do.

The roll rate sensor 111 and the yaw rate sensor 112 may also be referred to as a gyro sensor or an angular velocity sensor. The roll rate sensor 111 may detect a change in a roll axis, and the yaw rate sensor 112 may measure a change in a yaw axis.

Specifically, the roll rate sensor 111 may output the rotational angular velocity of the vehicle 100 in the roll direction. Rotation in the roll direction of the vehicle 100 means rotation around an axis parallel to the front-rear direction of the vehicle 100 .

The yaw rate sensor 112 may output an angular velocity of rotation of the vehicle 100 in the yaw direction. The yaw direction rotation of the vehicle 100 means rotation around an axis parallel to the left-right direction of the vehicle 100 .

The longitudinal acceleration sensor 113 may output acceleration in the height direction of the vehicle 100, that is, acceleration in the Z-axis direction shown in FIG. 3, and the lateral acceleration sensor 114 may output acceleration in the lateral direction of the vehicle , that is, the acceleration in the Y-axis direction shown in FIG. 3 can be output.

A roll rate sensor 111, a yaw rate sensor 112, a longitudinal acceleration sensor 113, and a lateral acceleration sensor 114 may be respectively provided, and some of them may be implemented as one sensor module. For example, the roll rate sensor 111 and the yaw rate sensor 112 are implemented by one gyro sensor module, or the lateral acceleration sensor 114 and the longitudinal acceleration sensor 113 are implemented by one acceleration sensor module. It can be.

The control unit 120 may determine the possibility of overturning the vehicle 100 based on the output of the motion state detection unit 110 . At this time, the output of the movement state detection unit 110 may be used to determine the possibility of rollover after high frequency noise is removed through a low pass filter. A description of a process in which the control unit 120 determines the possibility of overturning the vehicle 100 will be described later.

If it is determined that there is a possibility of rollover, the controller 120 may transmit a trigger signal for airbag deployment to the airbag module 130 .

The control unit 120 includes at least one memory storing a program for performing the above-described operation and an operation to be described later, and at least one processor executing the stored program. At least one memory and at least one processor may be directly on one chip and referred to as an electronic control unit (ECU).

5 is a diagram illustrating rotational kinetic energy in a roll direction generated by a lateral force, and FIGS. 6 and 7 are diagrams illustrating an effective center of gravity height when a vehicle is caught and overturned.

The control unit 120 uses various sensor data output from the motion state detection unit 110 to reflect the rotational kinetic energy in the roll direction caused by the lateral force, the minimum potential energy for generating roll direction overturning, and the effective hooking height. A roll overturn index value representing the possibility of overturn in the roll direction can be calculated. Hereinafter, a process in which the control unit 120 calculates the roll overturn index value will be described in detail.

The controller 120 may calculate the rollover index value (Index _rollover ) according to [Equation 1] below.

[Equation 1]

Here, E _roll represents rotational kinetic energy in the roll direction, E _potential represents the minimum potential energy for generating roll direction overturn, and SF (Safety Factor) is a factor reflecting the height of an obstacle that causes roll direction overturn.

First, parameters used for calculation of rotational kinetic energy in the roll direction and minimum potential energy for generating roll direction overturning will be described.

Referring to FIG. 5 , the height of the center of gravity (h) is measured from the ground to the center of gravity (C) of the vehicle 100 when both the wheels 52 provided on the left and right sides of the vehicle 100 come into contact with the ground. represents the height of

Overturning of the vehicle 100 in the roll direction may occur when the vehicle 100 traveling laterally gets caught in an obstacle O. At this time, the angle α between the straight line representing the distance l between the center of gravity C and the contact point P of the vehicle 100 and the obstacle O and the straight line representing the vehicle width W, the vehicle 100 ) can be used to calculate the angle of inclination in the roll direction, that is, the roll angle φ, for calculating the roll direction rotational kinetic energy and the minimum potential energy for generating roll direction overturning.

The control unit 120 may obtain roll direction rotational kinetic energy (E _roll ) generated by the lateral force using Equation 2 below.

[Equation 2]

Here, I ₀ represents the rotational moment of inertia in the roll direction, and h represents the height of the center of gravity of the vehicle as described above. Ay represents the lateral acceleration (lateral acceleration).

The roll direction rotational kinetic energy (E _roll ) calculated by [Equation 2] may represent rotational kinetic energy by the integral value of the lateral acceleration exceeding the reference lateral acceleration (SSF: Static Stability Factor).

The reference lateral acceleration (Ay _SSF(φ) ) is calculated as the static reference lateral acceleration by the magnitude of the inertial lateral acceleration that exceeds the gravitational acceleration g that prevents roll overturning at an arbitrary roll angle φ and causes roll overturn.

The rollover hindering moment (m1) due to the gravitational acceleration (g) can be calculated by [Equation 3] below, and the overturning moment (m2) due to the lateral inertial force can be calculated by [Equation 4] below there is.

[Equation 3]

[Equation 4]

Therefore, the static reference lateral acceleration Ay _SSF(φ) capable of generating an additional roll motion at an arbitrary roll angle after the front and rear wheels located on the moving direction side of the vehicle 100 are lifted is given by [Equation 5] can be calculated using

[Equation 5]

The control unit 120 may obtain the rotational kinetic energy E roll in the roll direction using the static reference lateral acceleration Ay _SSF(φ) calculated by _[ Equation 5] above.

)를 적분하여 무게중심 높이(h)로 나누면 롤레이트 예상치가 되고, 이를 활용하여 롤 방향 회전 운동 에너지(E_roll)를 획득할 수 있다. Referring again to [Equation 2], lateral acceleration greater than or equal to the static reference lateral acceleration that causes roll overturning (

) is integrated and divided by the height of the center of gravity (h) to obtain the estimated roll rate, and by using this, the rotational kinetic energy (E _roll ) in the roll direction can be obtained.

The minimum potential energy (E _potential ) for generating roll direction overturning can be obtained using [Equation 6] below.

[Equation 6]

Here, m represents the mass of the vehicle 100, and the remaining parameters g, l, and α are as described above.

Meanwhile, the height h of the center of gravity used to calculate the rotational kinetic energy in the roll direction according to [Equation 2] is a fixed value of the vehicle 100 . In general, a vehicle with a high center of gravity height (h) is more likely to overturn than a vehicle with a low center of gravity height (h).

However, when the vehicle 100 is overturned by being caught on an obstacle located on the ground during a lateral movement, the possibility of overturning the vehicle 100 may vary depending on the height of the obstacle.

For example, as shown in FIG. 6 , when the height of the obstacle O is low, the distance between the position P where the vehicle 100 is caught on the obstacle O and the center of gravity C of the vehicle 100 Since the height difference h' is large, there is a high possibility that the vehicle 100 is overturned.

Conversely, as shown in FIG. 7 , when the height of the obstacle O is high, the height difference between the position P where the vehicle 100 is caught on the obstacle O and the center of gravity C of the vehicle 100 Since (h') is not large, the possibility that the vehicle 100 is overturned becomes relatively small.

Therefore, if only the height h of the center of gravity of the vehicle 100 is simply reflected in determining the possibility of rollover of the vehicle 100, the reliability of the result of determining the possibility of rollover is lowered and the possibility of erroneous deployment of the airbag increases.

Therefore, in calculating the rollover index value (Index _rollover ), the control unit 120 may use SF reflecting the height of the obstacle causing the rollover as shown in [Equation 1]. Hereinafter, description will be made with reference to FIG. 8 .

8 to 10 are graphs showing the roll angle and lateral speed measured in various environments, and FIG. 11 is a graph showing the SF value according to the height of the effective center of gravity of the vehicle.

In an embodiment to be described later, the height of the center of gravity of the vehicle 100 reflecting the height of the vehicle 100 over the obstacle O will be referred to as the effective center of gravity height H _eff .

The control unit 120 may calculate the effective center of gravity height H _eff of the vehicle 100 according to Equation 7 below.

[Equation 7]

Δroll represents an increase in roll angle that occurs when the vehicle 100 is hit by an obstacle while moving in a lateral direction, and ΔV _y represents an amount of decrease in lateral speed. For example, the roll angle increase amount and the lateral speed decrease amount may be values measured for 40 ms.

8 is a graph showing lateral speed and roll angle measured in a curb environment, and FIGS. 9 and 10 are graphs showing lateral speed and roll angle measured in different types of soil environments.

As shown in FIG. 8, in the curve environment, the lateral speed change was 9.2 kph and the roll angle change was 6.6 degrees, and in the soil environment of FIG. 9, the lateral speed change was 4.2 kph and the roll angle change was 5.4 degrees. In the soil environment of 10, the change in lateral speed was 4.2 kph and the change in roll angle was measured at 7.9 degrees.

If the effective center of gravity height (H _eff ) is calculated using the ratio between the lateral speed change amount and the roll angle change amount according to [Equation 7], a higher effective center of gravity height (H _eff ) is calculated in the soil environment compared to the curb environment can confirm that it is. This is a result that can reflect the higher probability of overturning in a soil environment than in a curve environment even for vehicles with the same center of gravity height.

Therefore, like the vehicle 100 according to an embodiment, in determining the possibility of overturning, not only the height of the center of gravity of the vehicle but also the factor (effective height of the center of gravity) that varies depending on the height of the obstacle causing the overturning environment or the tripping overturn is reflected. By doing so, it is possible to more accurately and quickly deploy the airbag.

An example of the relationship between the effective center of gravity height (H _eff ) and SF obtained through experiments and simulations using vehicles having various center of gravity heights (h) and obstacles having various types and heights is shown in the graph of FIG. shown in The larger the SF, the greater the possibility of roll direction overturning.

The controller 120 stores the relationship between the effective center of gravity height (H _eff ) and SF in advance, and obtains the SF value according to the effective center of gravity height (H _eff ) when calculating the rollover index value (Index _rollover ). It can be reflected in [Equation 1].

The control unit 120 calculates the rollover index value (Index _rollover ) according to [Equation 1] when the preset rollover possibility determination condition is satisfied, and whether or not the airbag is deployed based on the calculated rollover index value. can decide

For example, the rollover possibility determination condition may include ① on of a tripped rollover flag, ② a roll angle exceeding a reference value, and ③ a lateral speed exceeding a reference value. That is, the control unit 120 may determine the possibility of overturning by calculating the rollover index value when the jammed overturn flag is turned on, the roll angle exceeds the second reference value, and the lateral speed exceeds the third reference value.

At this time, the control unit 120 may receive the sensor data output from the sensor 110 in real time, determine whether a rollover possibility determination condition is satisfied, and calculate a roll overturn index value.

) 걸림 전복 플래그가 온 되는 것으로 판단할 수 있다. 횡가속도의 절대값이 0.9g보다 작아지면 걸림 전복 플래그는 오프(Off)될 수 있다.The control unit 120 may determine that the jam overturn flag is turned on when the magnitude of the lateral acceleration, that is, the absolute value of the lateral acceleration is greater than the first reference value. For example, the first reference value may be set to 1.2g, and the control unit if the absolute value of the lateral acceleration is greater than 1.2g (

) It can be determined that the jam overturn flag is turned on. When the absolute value of the lateral acceleration is less than 0.9 g, the jammed overturn flag may be turned off.

When determining on/off of the jamming overturn flag, the lateral acceleration Ay may use a value input after low pass filtering under the condition of time constant T = 0.07.

Meanwhile, when the vehicle 100 is caught on an obstacle while moving in the lateral direction, force is applied in the opposite direction to the moving direction and lateral acceleration is reduced. Therefore, when the absolute value of the lateral acceleration exceeds the first reference value, the sign of the lateral acceleration (V _y ) and the lateral acceleration (A _y ) being opposite may be further included in the flag-on condition of the trip overturn. At this time, the lateral acceleration (Ay) may use a value input after low-pass filtering under the condition of time constant T = 0.04.

When the jammed overturn flag is turned on, the controller 120 may determine whether the roll angle is greater than the second reference value and whether the lateral speed is greater than the third reference value. Here, the ordinal numbers used for the first reference value, the second reference value, and the third reference value are for distinguishing each other, and do not indicate a rank or relationship between the reference values.

Additionally, it is also possible to further include the fact that the direction in which the roll angle of the vehicle 100 increases and the direction in which the lateral speed increases coincide (sign(Δroll)=sign(ΔV _y )) in the rollover possibility determination condition.

, 횡속도가 5kph보다 크고(

), 롤 각도의 증가 방향과 횡속도의 증가 방향이 일치하면, 제어부(120)가 [수학식 1]에 따른 롤 전복 인덱스값을 산출할 수 있다. For example, if the absolute value of the roll angle is greater than 3 degrees (

, the lateral speed is greater than 5 kph (

), when the increasing direction of the roll angle coincides with the increasing direction of the lateral speed, the controller 120 may calculate the roll overturn index value according to [Equation 1].

Hereinafter, a method of estimating the lateral speed included in the rollover possibility determination condition will be described.

)을 산출할 수 있다. The control unit 120 determines the estimated lateral speed of the vehicle 100 based on Equation 8 below (

) can be calculated.

[Equation 8]

는 횡속 추정값을 나타내고,

는 횡속 변화율을 나타낸다.

를 적분하여

를 획득할 수 있고, 획득된 값을 다시 [수학식 8]에 사용할 수 있다.

의 초기값은 0을 사용할 수 있다. 또한, Ay는 횡가속도 센서(113)의 출력을 나타내고, ωz는 요레이트 센서(112)의 출력을 나타내며, Vx는 휠속도 센서(115)의 출력(차속)을 나타내고,

는 롤 레이트의 적분에 의해 산출되는 롤 추정치를 나타낸다.

는 횡속 추정 게인을 나타낸다.here,

Represents the estimated value of the transverse speed,

represents the rate of change of the transverse speed.

by integrating

Can be obtained, and the obtained value can be used in [Equation 8] again.

The initial value of can be 0. In addition, Ay represents the output of the lateral acceleration sensor 113, ωz represents the output of the yaw rate sensor 112, Vx represents the output (vehicle speed) of the wheel speed sensor 115,

represents a roll estimate calculated by integrating the roll rate.

represents the transverse speed estimation gain.

12 is a graph showing changes in lateral velocity estimation gain according to the centripetal force of the vehicle.

는 횡적 거동이 존재하지 않는 경우에는 추정치 발산 방지를 위해 횡속을 0으로 보내기 위해 출력되고, 횡적 거동이 큰 경우에는 Pseudo 적분을 수행하여 횡속을 추정할 수 있다.

is output to set the lateral speed to 0 to prevent divergence of the estimated value when the lateral motion does not exist, and when the lateral motion is large, the lateral speed can be estimated by performing pseudo integration.

As shown in FIG. 9 , the lateral speed estimation gain may be determined as a larger value as the centripetal force determined by the yaw rate and the vehicle speed is smaller.

The control unit 120 may determine whether or not the above-described rollover possibility determination condition is satisfied using the lateral speed estimated by [Equation 8].

The control unit 120 may calculate a roll overturn index value (Index _rollover ) according to [Equation 1] when the above-described rollover possibility determination condition is satisfied. The controller 120 may determine that there is a possibility of rollover at the moment when the calculated rollover index value exceeds a preset reference value, and transmit a trigger signal for airbag deployment to the airbag module 130 . For example, a trigger signal for airbag deployment may be transmitted to the airbag module 130 at the instant when the calculated rollover index value exceeds 1.

In addition, the control unit 120 may output a warning notifying the user of the danger of overturning in a visual or audible manner through a user interface device (display, speaker) provided in the vehicle 100, or a public safety response point (PSAP). It is also possible to forward an emergency contact to the Safety Answering Position.

13 is a graph showing test results obtained by measuring a point in time at which a vehicle determines the possibility of rollover according to an embodiment.

Referring to FIG. 13, the control unit 120 turns on the jamming overturn flag when the absolute value of the lateral acceleration exceeds the first reference value, whether the roll angle is greater than the second reference value, and whether the lateral speed is greater than the third reference value. judge When the roll angle is greater than the second reference value and the lateral speed is greater than the third reference value while the jammed overturn flag is continuously on, the control unit 120 calculates the roll overturn index value, and the roll overturn index value is preset When the fourth reference value (ex. 1) is exceeded, it can be determined that there is a possibility of overturning.

In this experiment, it can be confirmed that the time at which the possibility of overturning is determined appears 170 ms faster than the time at which the vehicle's lateral motion or effective center of gravity height is not considered according to the conventional method. That is, when the possibility of rollover of the vehicle 100 is determined according to the above-described embodiment, the possibility of rollover is determined more accurately at an earlier time, thereby enabling rapid deployment of the airbag and reducing the possibility of misdeployment of the airbag.

Hereinafter, a vehicle control method according to an exemplary embodiment will be described. The vehicle 100 according to the above-described embodiment may be applied to the vehicle control method according to an embodiment. Therefore, the contents described above with reference to FIGS. 1 to 13 may also be applied to a method for controlling a vehicle according to an exemplary embodiment, even if no special mention is made.

14 is a flowchart of a method for controlling a vehicle according to an exemplary embodiment. In this embodiment, it is assumed that sensor data such as roll rate, yaw rate, longitudinal acceleration, lateral acceleration, and vehicle speed measured in real time by the sensing unit 110 of the vehicle 100 is input to the control unit 120. .

Referring to FIG. 14 , the control unit 120 determines whether the jam overturn flag is turned on (310). The control unit 120 may determine that the jam overturn flag is turned on when the magnitude of the lateral acceleration, that is, the absolute value of the lateral acceleration is greater than the first reference value. In addition, when the absolute value of the lateral acceleration exceeds the first reference value, the sign of the lateral acceleration (V _y ) and the lateral acceleration (A _y ) being opposite may be further included in the tripping overturn flag-on condition.

When the jammed overturn flag is turned on (YES in 310), it is determined whether the absolute value of the roll angle exceeds the second reference value (311) and whether the lateral speed exceeds the third reference value (312). In the flow chart, the determination of the roll angle was described prior to the determination of the lateral speed, but the embodiment does not place restrictions on the order of determination of the roll angle and the lateral speed, so it is possible to determine the lateral speed first or to determine both at the same time. .

If the absolute value of the roll angle exceeds the second reference value (YES in 311) and the lateral speed exceeds the third reference value (YES in 312), the control unit 120 calculates the roll overturn index according to [Equation 1] described above A value (Index _rollover ) can be calculated. Since the description of the SF factor used to calculate the roll overturn index value or the effective center of gravity height (H _eff ) used to calculate the SF factor is the same as that described in the embodiment of the vehicle 100 above, redundant descriptions omit

If the calculated roll overturn index value exceeds the fourth reference value (Yes in 314), the control unit 120 can predict that overturn will occur, that is, determine that there is a possibility of overturn (315).

If it is determined that there is a possibility of rollover, the controller 120 may transmit a trigger signal to the airbag module 130 to deploy the airbag.

In addition, it is also possible to visually or audibly output a warning notifying the user of the danger of overturning through a user interface device (display, speaker) provided in the vehicle 100 .

It is also possible to forward an emergency contact to a Public Safety Answering Position (PSAP).

According to the vehicle and its control method according to the above-described embodiment, in determining the possibility of overturning the vehicle, the total kinetic energy in the roll direction due to the lateral force is taken into account, and the effective center of gravity height, which varies depending on the type of road surface or obstacle when a tripped overturn occurs The possibility of overturning can be accurately determined at a quick time by reflecting the change in roll angle and the ratio of the change in lateral speed over a certain period of time, and through this, early deployment of the airbag can be implemented to secure stability.

The above description is merely an example of the technical idea, and various modifications, changes, and substitutions may be made by those skilled in the art without departing from the essential characteristics. Therefore, the embodiments disclosed above and the accompanying drawings are intended to explain rather than limit the technical idea, and the scope of the technical idea is not limited by these embodiments and the accompanying drawings. The scope of protection should be interpreted according to the scope of claims below, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of rights.

100: vehicle
110: sensing unit
120: control unit
130: airbag module

Claims (18)

an airbag module including at least one airbag and deploying the airbag when a trigger signal is input;
Motion state detection unit for detecting roll rate, lateral acceleration and wheel speed of the vehicle; and
Obtain rotational kinetic energy of the vehicle in the roll direction using the detected roll rate and the detected lateral acceleration, and use an effective center of gravity height that varies depending on a rollover environment and rotational kinetic energy in the roll direction to obtain the rotational kinetic energy of the vehicle in the roll direction. A vehicle comprising a; control unit for determining the possibility of overturning of the vehicle. According to claim 1,
The control unit,
A vehicle that integrates a difference between a reference lateral acceleration and a lateral acceleration detected by the motion state sensor, and obtains rotational kinetic energy in the roll direction using the integrated difference. According to claim 2,
The reference lateral acceleration is,
A vehicle that represents the amount of inertial lateral acceleration that causes roll overturn in excess of the gravitational acceleration that prevents roll over at any roll angle. According to claim 1,
The control unit,
A vehicle that obtains the effective center of gravity height by using a ratio of an increase in roll angle of the vehicle and a decrease in lateral speed of the vehicle. According to claim 1,
The control unit,
A vehicle that obtains a factor representing the possibility of overturning the vehicle according to the height of the effective center of gravity, and determines the possibility of overturning the vehicle using the obtained factor. According to claim 1,
The control unit,
A roll overturn index value is calculated using the rotational kinetic energy of the vehicle in the roll direction, the height of the effective center of gravity, and the minimum potential energy for roll over of the vehicle, and the calculated roll overturn index value exceeds a preset reference value. If it does, the vehicle that is determined to have a possibility of overturning the vehicle. According to claim 6,
The control unit,
A vehicle that transmits a trigger signal for airbag deployment to the airbag module when it is determined that there is a possibility of rollover of the vehicle. According to claim 6,
The control unit,
A vehicle that calculates the rollover index value when a predetermined rollover possibility determination condition is satisfied. According to claim 8,
The condition for determining the possibility of overturning is,
The magnitude of the lateral acceleration of the vehicle exceeds a first reference value, the signs of the lateral acceleration of the vehicle and the lateral acceleration of the vehicle are opposite, the direction in which the roll angle of the vehicle increases and the lateral velocity of the vehicle A vehicle including at least one of increasing directions being the same, a roll angle of the vehicle exceeding a second reference value, and a lateral speed of the vehicle exceeding a third reference value. According to claim 1,
The movement state sensor,
A vehicle that includes a roll rate sensor, a lateral acceleration sensor, and a wheel speed sensor. detect vehicle roll rate, lateral acceleration and wheel speed;
obtaining rotational kinetic energy of the vehicle in a roll direction using the detected roll rate and the detected lateral acceleration;
determining a rollover possibility of the vehicle using an effective center of gravity height that varies depending on a rollover environment and rotational kinetic energy in the roll direction;
and transmitting a trigger signal to an airbag module when it is determined that there is a possibility of the vehicle overturning. According to claim 11,
Obtaining rotational kinetic energy in the roll direction of the vehicle is
A control method of a vehicle comprising integrating a difference between a reference lateral acceleration and the sensed lateral acceleration, and obtaining rotational kinetic energy in the roll direction using the integrated difference. According to claim 12,
The reference lateral acceleration is,
A vehicle control method that indicates the magnitude of inertial lateral acceleration that causes roll overturn by exceeding the gravitational acceleration that prevents roll overturn at a certain roll angle. According to claim 11,
The vehicle control method further comprising obtaining the effective center of gravity height by using a ratio of an increase in roll angle of the vehicle and a decrease in lateral speed of the vehicle. According to claim 11,
Acquiring a factor representing the possibility of overturning the vehicle according to the height of the effective center of gravity; further comprising,
Determining the possibility of overturning the vehicle,
and determining whether the vehicle is overturned by using the obtained factor. According to claim 11,
Determining the possibility of overturning the vehicle,
A roll overturn index value is calculated using the rotational kinetic energy of the vehicle in the roll direction, the effective center of gravity height, and the minimum potential energy for roll overturn of the vehicle, and the calculated roll overturn index value exceeds a preset reference value. Control method of a vehicle comprising: determining that there is a possibility of overturning of the vehicle. 17. The method of claim 16,
Further comprising determining whether a preset rollover possibility determination condition is satisfied;
A vehicle control method of calculating the rollover index value when the rollover possibility determination condition is satisfied. 18. The method of claim 17,
The condition for determining the possibility of overturning is,
The magnitude of the lateral acceleration of the vehicle exceeds a first reference value, the signs of the lateral acceleration of the vehicle and the lateral acceleration of the vehicle are opposite, the direction in which the roll angle of the vehicle increases and the lateral velocity of the vehicle A method for controlling a vehicle, comprising at least one of increasing directions being the same, a roll angle of the vehicle exceeding a second reference value, and a lateral speed of the vehicle exceeding a third reference value.

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