KR101526621B1 - Method for controlling vehicle of integration type - Google Patents

Abstract

The present invention relates to an intelligent vehicle control method for safety, and more particularly, to an intelligent vehicle control method for safety, which comprises a vehicle state measuring step of detecting a change in an operating state of a traveling vehicle and a surrounding vehicle through a sensor mounted on the vehicle; A data estimating step of receiving the state information of the vehicle through the vehicle state measuring step and converting the force applied to the wheel, the lateral velocity of the vehicle, and the road surface friction coefficient into data; Determining a control mode by determining a longitudinal direction and a lateral direction control state of the vehicle through the data estimation step; A longitudinal and lateral calculation step of calculating a target yaw rate in the lateral direction control by calculating the target acceleration during the longitudinal control through the situation determination step; Calculating longitudinal and yaw moments for following the target acceleration and the target yaw rate calculated in the vertical and horizontal direction first calculation step; And a third longitudinal and lateral calculation step of calculating an input value for operating the actuator by applying the longitudinal force and the yaw moment calculated in the longitudinal and lateral second calculation steps to the vehicle under travel, By combining the system ESC and AFS and the driver assistance system SCC / CA, it is possible to define the control strategy and the control mode according to the driving situation, and to calculate the driving situation judgment data which can determine the changing point of the control mode, In addition to improving the stability of the vehicle and reducing unwanted control input, it is possible to minimize the driver's sense of heterogeneity and to facilitate smooth traffic flow So that it is effective in improving the merchantability.

Description

[0001] The present invention relates to an integrated vehicle control method,

In particular, the present invention relates to an integrated vehicle control method, and more particularly, to an integrated vehicle control method, in which a throttle, a steering angle, an angle of a vehicle mounted on a vehicle Braking, etc., to ensure lateral stability and to ensure longitudinal stability to prevent collision between opponent vehicles.

In general, an ECU (Electronic Control Unit) used in a vehicle is a device for inputting a detection signal from various sensors to operate various actuators by grasping the state of the vehicle, an input interface for converting a sensing signal inputted from various sensors, A microcomputer for performing a calculation operation or a logical operation of input data, and an output interface for converting the result into an operation signal of a driver.

Vehicle control systems associated with the ECU include Electronic Power Steering (EPS), Ani-Lock Break System (ABS), Continuous Damper Control (CDC), and the like. These include suspension devices, braking devices, steering devices, So that the safety and ride comfort of the vehicle are enhanced.

Especially, ECS (Electronic Control Suspension) is equipped with electronically controlled hydraulic device according to the driving condition of the car, so that the strength and the height of the suspension are automatically controlled by the road condition and the speed to secure the grounding force and driving force to the road surface. (Advanced Safety Vehicle) improves the safety of automobiles through technologies such as drowsy driving alarm system, nighttime obstacle detection system and danger warning system. So that the traffic accident deaths caused by the operation of the vehicle can be minimized.

Recently, the demand for the stability of the vehicle and the convenience of the driver during driving has increased, and active active safety systems and driver assistance systems of the vehicle have been actively studied.

The active safety systems include Electronic Stability Control (ESC) and Active Front Steering (AFS). Operator assistance systems include SCC (Smart Cruise Control) or ACC (Adaptive Cruise Control), CA (Collision Avoidance), LKS Keeping Support). Currently, these systems have reached the stage of mass production, but each individual system operates independently.

Independent operation of several kinds of control systems means that if a system with high control authority is required by controlling the system by each system, if there is a possibility of collision between control inputs, other systems having low control authority do not operate. It can lead to another dangerous situation because it controls only one of the many dangerous situations that the car has today.

 Typical examples are ESC (active safety system) and SCC (operator assist system). When the ESC is needed during the SCC operation, the SCC system will not operate because the transverse stability of the vehicle is guaranteed, Can cause a collision situation.

FIG. 1 shows a case where the forward vehicle decelerates when passing through a road having a small coefficient of friction on the right road surface while running on a straight road. When only longitudinal stability is controlled, braking on the asymmetric road surface is unstable, And control of only lateral stability can cause collision with the preceding vehicle.

Figures 2 and 3 are graphs showing longitudinal and lateral data for a conventional vehicle control system.

In FIG. 2, the SCC / CA represents the longitudinal control of the vehicle, the ESC represents the lateral control, the position error represents the difference between the center of the lane and the vehicle referee, and Clearance represents the difference between the driving vehicle and the forward vehicle . 2 (a), it can be seen that the SCC / AC is out of the lane in the decelerating section, and if the ESC is controlled with priority, the risk of collision may occur if the driver does not decelerate .

3 (a) and 3 (b), it can be seen that the target follow-up of the ESC, which is the lateral priority control, is not good when the velocity and the acceleration are viewed, The error rate (Yaw rate error) indicates that when the SCC / CA is longitudinally controlled, the error greatly increases and the vehicle becomes unstable.

Thus, in the conventional vehicle control system, longitudinal control is performed only when the longitudinal direction is unstable, and lateral control is performed only when the lateral direction is unstable. There is a problem that unexpected sudden deceleration due to excessive braking pressure causes an uneasiness to the driver or interrupts the traffic flow even if the horizontal stability and the longitudinal crash prevention are satisfied at the same time.

The present invention relates to an integrated vehicle control method for solving the above problems, and more particularly, to an integrated vehicle control method for determining a control mode by determining a current situation of a vehicle in operation, calculating a movement of the vehicle suitable for the control mode, , Braking of a wheel mounted on a vehicle, etc. to ensure lateral stability and to prevent longitudinal collision between opponent vehicles.

The present invention comprises a vehicle state measuring step of measuring a characteristic parameter of a vehicle and detecting a change according to an operating state of a traveling vehicle and a surrounding vehicle through a sensor mounted on the vehicle; A data estimating step of receiving the state information of the vehicle through the vehicle state measuring step and converting the force applied to the wheel, the lateral velocity of the vehicle, and the road surface friction coefficient into data; Determining a control mode by determining a longitudinal direction and a lateral direction control state of the vehicle through the data estimation step; A longitudinal and lateral calculation step of calculating a target yaw rate in the lateral direction control by calculating the target acceleration during the longitudinal control through the situation determination step; Calculating longitudinal and yaw moments for following the target acceleration and the target yaw rate calculated in the vertical and horizontal direction first calculation step; And a longitudinal and lateral third calculation step of calculating an input value for operating the actuator by applying the longitudinal force and the yaw moment calculated in the longitudinal and lateral second calculation steps to the vehicle under travel.

As described above, the present invention integrates the ESC and the AFS, which are vehicle active safety systems that have previously operated independently, and the SCC / CA, which is a driver assistance system, to define a control strategy and a control mode for each driving situation, It is possible to increase the stability of the vehicle and increase the reliability of the vehicle by increasing the stability of the vehicle even in a situation where a combination of longitudinal and lateral danger is required, Thereby minimizing a driver's sense of heterogeneity and at the same time helping to smooth traffic flow, thereby improving commerciality.

1 is a view showing a vehicle running and a vehicle decelerating on a conventional straight road,
2 is a graph showing longitudinal control effects in a conventional vehicle control system,
3 is a graph showing the lateral control effect in a conventional vehicle control system,
4 is a flowchart showing an integrated vehicle control method of the present invention;
5 and 6 are diagrams showing a running vehicle and a forward vehicle in the integrated vehicle control method of the present invention,
7 is a graph showing the state of the vehicle by the side slip angle in the lateral direction control in the integrated vehicle control method of the present invention.

4 to 7 are flowcharts showing an integrated vehicle control method of the present invention. Fig. 5 and Fig. 6 are flowcharts of an integrated vehicle control method of the present invention. And FIG. 7 is a graph showing the state of the vehicle by the side slip angle in the lateral direction control in the integrated vehicle control method of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 to 7, the integrated vehicle control method of the present invention includes a vehicle state measurement step S10, a data estimation step S20, a situation determination step S30, a vertical and horizontal direction first calculation step (S40), a vertical and horizontal direction second calculation step (S50), and a vertical and horizontal direction third calculation step (S60), so that a complex control input in the longitudinal direction and the lateral direction as well as the conventional longitudinal and transverse direction risk are required The basic feature of the present invention is to improve the stability of the vehicle even in a dangerous situation and to reduce the unwanted control input to minimize the driver's sense of heterogeneity and at the same time to facilitate the smooth traffic flow and to improve the merchantability.

Hereinafter, each component of the integrated vehicle control method of the present invention will be described with reference to the accompanying drawings.

4, the integrated vehicle control method includes a vehicle state measurement step S10 for sensing a state of a running vehicle and a state of a surrounding vehicle, a data estimation step S20 for converting the state of the vehicle into data, (S30) for determining a longitudinal direction and a lateral direction control, a vertical and horizontal direction calculation step (S40) for calculating a target acceleration and a target yaw rate, a longitudinal and lateral direction second calculation step A calculation step S50, and a longitudinal and lateral third calculation step S60 for calculating an input value for operating the actuator.

The vehicle condition measurement step S10 measures a plurality of characteristic parameters determined according to specifications of the vehicle, and senses a change depending on the operating state of the vehicle traveling on the road and the operation state of the surrounding vehicle through the sensor mounted on the vehicle .

The parameters measured in the vehicle condition measuring step S10 include the weight of the vehicle, the center of gravity, the height, the yaw rate, the rotational stiffness coefficient, etc., which are interlocked with the ECU so as to have data on the basic specifications of the vehicle, Acceleration, yaw rate, steering angle, speed, engine RPM, and turbine RPM through a number of sensors, And is used for vehicle control.

The data estimating step (S20) receives the state information of the vehicle through the vehicle state measuring step (S10), estimates the force applied to the wheels, the lateral velocity of the vehicle, and the road surface friction coefficient, and converts them into data.

The situation determination step S30 determines the longitudinal control and the lateral control state of the vehicle through the force applied to the wheel estimated from the data estimating step S20, the lateral velocity of the vehicle, and the road surface friction coefficient data, .

At this time, the longitudinal index and the lateral index are as follows.

A longitudinal index (an index for determining the risk of collision and a risk for the driver visually feeling through the ratio of the smallest distance at which the vehicle can physically stop and the current relative distance)

A lateral index (indicating the difference between the lateral slip angle and the target rate of the vehicle and the current rate)

In the vertical and horizontal direction first calculation step S40, the target acceleration is calculated at the time of the longitudinal direction determination and the yaw rate at the time of the lateral direction determination through the situation determination step S30.

The target acceleration for longitudinal control and the target yaw rate for lateral control are calculated on the basis of the calculated data using the variables detected according to the operating state of the vehicle in operation, To determine the control mode, and to follow the forward vehicle.

Here, the data in the vertical and horizontal direction first calculation step S40 includes an index such as a collision alarm index, a reverse collision time, a rate, and a side slip angle.

On the other hand, as the approaching speed to the preceding vehicle is fast and the distance from the running vehicle to the preceding vehicle is small, the risk of collision with the preceding vehicle becomes large, so that longitudinal control of the vehicle is required.

Therefore, in order to determine the longitudinal control point of such a vehicle, it is possible to determine the running situation through the collision alarm index (X) and the reverse collision time (TTC- ¹ ) reflecting the relative distance and relative speed with the preceding vehicle .

The collision alarm index (X) represents a value at which a collision can occur between a running vehicle and a nearby vehicle. The collision alert index (X) is an inter-vehicle distance measured using a sensor that takes into account the braking distance of the vehicle and the operation delay of the driver, , And the risk of collision with the preceding vehicle is quantified by using the distance between the preceding vehicle and the preceding vehicle, the relative speed, the speed of the traveling vehicle, the operation delay of the system and the driver, It is a dimensionless constant.

Referring to FIG. 5, the equation for calculating the index for the crash warning index X is as follows.

d _rel : relative distance to preceding vehicle

d _w : Minimum distance for avoiding collision with the preceding vehicle considering system delay time and driver delay time

d _br : Minimum distance to prevent collision with forward vehicle considering system latency

The collision time (TTC) is the time until the preceding vehicle stops and the vehicle does not decelerate, and the collision time (TTC) emits when the relative speed is zero, that is, when the two vehicles stop. And the inverse collision time (TTC ^-1 ) is calculated.

Referring to FIG. 6, the equation for calculating the index for the collision time (TTC) is as follows.

TTC (Time to Collision): The time required for collision between the driving vehicle and the preceding vehicle. The value divided by the relative distance

In FIG. 6, the Looming effect represents the degree to which the driver visually senses the approaching speed of the object. Thus, it can be seen that the looming effect due to the visual effect of the driver is closely related to the collision time (TTC).

When the vehicle-to-vehicle distance is small, the looming effect due to the variation of the vehicle-to-vehicle distance is considerably large. As a result, the inverse collision time (TTC ^-1 ) is used as a parameter to reflect the emotional state of the driver in a low- When the speed is constant, most of the driver follows the speed of the preceding vehicle constantly, and the time gap of the driver maintains a constant value.

Therefore, steady-state driving can be defined as a situation in which the inverse collision time (TTC- ¹ ) satisfies a predetermined value or less. However, as a result of analysis of the rapid driving data of the driver with a high possibility of collision, As the reverse collision time increases gradually, it can be judged as a dangerous situation and it is possible to determine the time when the longitudinal control is required.

On the other hand, lateral control of the vehicle is required when the vehicle under / over steer or lateral slip becomes large.

Therefore, in order to determine the time required for the lateral control, it is necessary to judge the running situation through the rate of the state variable and the side slip angle, which are important in the lateral movement of the vehicle.

The rate is a value that can be sufficiently obtained through the sensor regarding the lateral movement of the vehicle. The rate of the vehicle is determined by comparing the target rate value with the target rate value for improving the adjustment, The target rate can be obtained by the following equation.

Since the target rate is aimed at reaching a steady state quickly according to the steering change of the driver, the target rate can be obtained by setting the Dynamics term to 0 in the above equation, and the calculation result is as follows.

d is the target yaw rate when the driver turns. Since it is a steady turn, we consider the first-order transfer function considering the driver delay in the rate of steady turning obtained by summarizing the equation by setting the left-hand side to 0 and setting the target value to 0.

On the other hand, the target rate based on the rate for controlling the vehicle and the target rate for the side slip angle are used as the target rate by multiplying the weight according to the situation.

The side slip angle relates to the risk that the vehicle slides sideways. In the case of a vehicle having an understeer turning characteristic, when the lateral acceleration acting on the vehicle during turning is greater than the default value of the vehicle, The trajectory can not follow the turning trajectory desired by the driver, and the driver departs from the driving lane.

In this case, since the lateral slip angle is not a state variable that can be measured by the sensor, such as a rate, it is applied to the control logic through estimation. The index, which is an index used for lateral control, and the lateral slip angle are correlated It is very deep.

Although it is best to control these two kinds of state variables at the same time, it is impossible to control both state variables at the same time because of the relation between them and the restriction on the control input. Therefore, the lateral control is basically a control operation And the side slip angle is controlled when the side slip angle becomes a predetermined value or more.

7, the area inside the dotted line formed in the direction perpendicular to the center shows that the side slip angle is a safe area that does not affect the stability of the vehicle. Therefore, when the side slip angle is in a safe area If it is present, it is necessary to control the yaw rate to improve the stability. Otherwise, stabilize the vehicle through the side slip angle control.

The longitudinal and lateral second calculation step S50 calculates a longitudinal force and a yaw moment for following the target acceleration and the target yaw rate calculated in the longitudinal and lateral direction first calculation step S40.

At this time, the equation for the longitudinal force calculated from the target acceleration and the yaw moment required for lateral control is as follows.

Longitudinal force due to target acceleration

Target yaw moment

The longitudinal and lateral third calculation step S60 may be performed by applying the longitudinal force and yaw moment calculated in the longitudinal and lateral second calculation step S50 to the vehicle in operation so as to actuate the actuator composed of the throttle, The input value is calculated.

At this time, the actuators to be operated are throttle, brake, and active steering device. Throttle device calculates input value through Reverse Dynamics, and input value is determined through Optimal Distribution for brake and active steering.

On the other hand, when the throttle is determined, the Optimal Distribution sets the longitudinal force to zero to determine the brakes and the active steering angle to satisfy the calculated yaw moment. This is because the active steering angle is used first The throttle is not used when the longitudinal force is a minus value, and the throttle is not used when the longitudinal force is a minus value. In this case, the brakes and the active steering So that the longitudinal direction and the lateral direction control can be simultaneously satisfied

As a result, when the vehicle is accelerating, the active steering angle is used first, not the braking, but the longitudinal steering control via the brake is abandoned when the active steering angle exceeds the limit. When the longitudinal force is negative, And the combination of the brakes and the active steering to simultaneously satisfy the longitudinal direction and the lateral directional control.

The integrated vehicle control method of the present invention configured as described above includes a vehicle state measurement step (S10) for sensing a state of a running vehicle and a state of a nearby vehicle, a data estimation step (S20) for converting a state of the vehicle into data, (S30) for determining a longitudinal direction and a lateral direction control, a vertical and horizontal direction first calculation step (S40) for calculating a target acceleration and a target yaw rate, a vertical and horizontal second calculation (S50) for calculating an input value for operating the actuator, and a longitudinal and lateral third calculation step (S60) for calculating an input value for operating the actuator, so that a complex control input in the longitudinal direction and the lateral direction as well as the conventional longitudinal and lateral direction risk It improves the stability of the vehicle even in a dangerous situation and minimizes the uncomfortable feeling of the driver by reducing unwanted control input, It is an inventor with one advantage.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood that various changes and modifications may be made without departing from the scope of the appended claims.

S10: Vehicle condition measurement step S20: Data estimation step
S30: Situation determination step S40: Vertical direction first calculation step
S50: vertical and horizontal direction second calculation step S60: vertical and horizontal direction third calculation step

Claims (1)

Measuring a characteristic parameter of the vehicle, detecting a change in the driving state of the vehicle and the surrounding vehicle through a sensor mounted on the vehicle;
A data estimating step of receiving the state information of the vehicle through the vehicle state measuring step and converting the force applied to the wheel, the lateral velocity of the vehicle, and the road surface friction coefficient into data;
Determining a control mode by determining a longitudinal direction and a lateral direction control state of the vehicle through the data estimation step;
A longitudinal and lateral calculation step of calculating a target yaw rate in the lateral direction control by calculating the target acceleration during the longitudinal control through the situation determination step;
Calculating longitudinal and yaw moments for following the target acceleration and the target yaw rate calculated in the vertical and horizontal direction first calculation step;
And a vertical and horizontal third calculation step of calculating an input value for operating the actuator by applying the longitudinal force and the yaw moment calculated in the vertical and horizontal second calculation step to the vehicle under travel.

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