KR101913127B1 - Method of controlling vehicle cornering - Google Patents

Abstract

A vehicle turning control method is disclosed. A vehicle turning control method according to an embodiment of the present invention includes determining whether a spin of a turning inner wheel is generated when the vehicle is turning and braking the turning inner wheel when a spin is generated in the turning inner wheel.

Description

[0001] METHOD OF CONTROLLING VEHICLE CORNERING [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a vehicle turning control method, and more particularly, to a vehicle turning control method capable of ensuring driving stability at the time of vehicle turning.

BACKGROUND ART [0002] Generally, an electronic brake system of a vehicle is provided with an anti-lock brake system (hereinafter abbreviated as ABS) that prevents a slip of a vehicle during braking to effectively obtain a strong and stable braking force, A Traction Control System (hereinafter referred to as TCS) that prevents slippage of the drive wheels when the vehicle suddenly rises or suddenly accelerates, a vehicle that improves the stability of the vehicle by controlling the brake hydraulic pressure by combining ABS and TCS And an electronic stability control (ESC).

Among them, ESC is basically designed to control the yawing behavior of the vehicle. It controls the braking device and the engine in a dangerous driving situation reaching the contact limit of the tire when the vehicle is turning, thereby guiding the driver to turn in a desired trajectory to be.

In a vehicle equipped with an electronic brake system for ensuring the stability of driving of such a vehicle, when the driver wishes to turn the vehicle to a desired trajectory, as the center of gravity of the vehicle moves to the outside of the turn, the turning inner wheel is brought into contact with the road surface . At this time, a torque is transmitted to the wheel through the drive shaft of the engine, and the spin is generated on the inner wheel of the drive wheel of which the contact force with the road surface is weakened. This causes a problem that the turning inner wheel loses its lateral force capable of supporting the road surface, and thus the driver can not turn around in the desired trajectory of the vehicle.

If this situation persists, ESC control is started to secure the turning stability of the vehicle, thereby reducing the engine driving force, thereby securing the turning stability of the vehicle.

The embodiment of the present invention provides a vehicle turning control device capable of ensuring the stability of turning of the vehicle and securing the acceleration performance before reaching the limit of the road surface on which the turning inner wheel can stand even if a spin occurs on the turning inner wheel at the time of turning of the vehicle. Method.

According to an aspect of the present invention, when the vehicle is turning, the wheel speed of the inner wheel and the wheel speed of the outer wheel are detected, and the wheel slip amount of the inner wheel and the wheel slip amount of the outer wheel are respectively And determining whether or not the spin of the turning inner wheel is generated by comparing the calculated wheel slip amount of the turning outer wheel and the calculated wheel slip amount of the turning inner wheel with a preset slip amount, The control unit detects the yaw rate of the vehicle and determines whether the difference between the detected yaw rate and the yaw rate demanded by the driver is smaller than a preset yaw rate, If the required yaw rate difference is smaller than a preset yaw rate, the turning inner wheel is braked, and the turning inner wheel is stopped And when the difference between the detected yaw rate and the yaw rate required by the driver is greater than a predetermined yaw rate, stopping the braking on the turning inner wheel and stopping the braking of the vehicle A turning control method may be provided.

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According to another aspect of the present invention, there is provided a control method for a vehicle, comprising: detecting a wheel speed of a turning inner wheel and a wheel speed of a turning outer wheel respectively when the vehicle is turning; And calculating a wheel slip amount of the outside turning wheel, and if the calculated wheel slip amount of the outer turning wheel is smaller than a predetermined slip amount and the calculated wheel slip amount of the calculated turning inner wheel is larger than the preset slip amount, And determining that a spin has occurred and braking the turning inner wheel when a spin is generated in the inner wheel of the turning wheel.

According to another aspect of the present invention, there is provided a control method for a vehicle, comprising: determining whether a spin of a turning inner wheel is generated when a vehicle is turning; detecting a yaw rate of the vehicle when a spin is generated in the turning inner wheel; A vehicle turning control method for braking the turning inner wheel may be provided if the difference between the yaw rates requested by the driver is smaller than a predetermined yaw rate.

According to another aspect of the present invention, there is provided a control method for a vehicle, comprising the steps of: determining whether or not a spin of a turning inner wheel is generated when a vehicle is turning; braking the turning inner wheel when a spin is generated in the turning inner wheel; When the difference between the detected yaw rate and the yaw rate demanded by the driver is greater than a preset yaw rate, stopping the braking of the turning inner wheel and stopping the braking of the vehicle A turning control method may be provided.

In the embodiment of the present invention, when spin is generated in the turning inner wheel at the time of vehicle turning, the understeer tendency of the vehicle is prevented by braking the turning inner wheel before reaching the limit of the road surface where the turning inner wheel can stand, It is possible to secure the acceleration performance by preventing unnecessary engine control for reducing the engine driving force.

1 is a brake hydraulic pressure circuit diagram of a vehicle turning control apparatus according to an embodiment of the present invention.
2 is a control block diagram of a vehicle turning control apparatus according to an embodiment of the present invention.
3 is a view for explaining braking of a turning inner wheel when a spin is generated in a turning inner wheel in a vehicle turning control apparatus according to an embodiment of the present invention.
4 is a control flowchart for a method of controlling a vehicle turning control apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below are provided by way of example so that those skilled in the art will be able to fully understand the spirit of the present invention. The present invention is not limited to the embodiments described below, but may be embodied in other forms. In order to clearly explain the present invention, parts not related to the description are omitted from the drawings, and the width, length, thickness, etc. of the components may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

The expression "and / or" is used herein to mean including at least one of the elements listed before and after. Also, the expression "coupled / connected" is used to mean either directly connected to another component or indirectly connected through another component. The singular forms herein include plural forms unless the context clearly dictates otherwise. Also, components, steps, operations and elements referred to in the specification as " comprises "or" comprising " refer to the presence or addition of one or more other components, steps, operations, elements, and / or devices.

1 is a brake hydraulic pressure circuit diagram of a vehicle turning control apparatus according to an embodiment of the present invention. 2 is a control block diagram of a vehicle turning control apparatus according to an embodiment of the present invention.

Referring to Figs. 1 and 2, the vehicle turning control apparatus includes a master cylinder MC which generates brake pressure by operation of the vacuum booster VB by the pressure of the brake pedal BP.

The master cylinder MC has two chambers MCP and MCS and has a first chamber MCP and a second chamber MCP for controlling the brake hydraulic pressure transmitted from the master cylinder MC to the wheel cylinders WFR and WRL. The normally open type cut valve SC1 is provided in the main hydraulic pressure line MF between the wheel cylinders WFR and WRL respectively provided on the left wheel FR and the rear wheel RL. Normally open type inlet valves PC1 and PC2 are provided in the hydraulic lines MFr and MFl between the normally open type cut valve SC1 and the wheel cylinders WFR and WRL. The normally open type inlet valves PC1 and PC2 are provided with check valves CV1 and CV2, respectively, in parallel. The brake fluid in the wheel cylinders WFR and WRL is returned to the master cylinder MC via the check valves SC1 and CV2 via the check valves CV1 and CV2.

Normally closed type outlet valves PC5 and PC6 are provided at the outlet sides of the wheel cylinders WFR and WRL. A low pressure accumulator RS1 for temporarily storing the brake fluid discharged from the wheel cylinders WFR and WRL and a brake fluid stored in the low pressure accumulator RS1 are provided at the outlet sides of the normally closed type outlet valves PC5 and PC6, A hydraulic pump HP1 and a motor M for forcedly refluxing to the wheel cylinder side are provided.

On the other hand, a normally open type inlet valve SI1 is provided between the suction side of the hydraulic pump HP1 and the auxiliary hydraulic line MFc between the first chamber MCP of the master cylinder MC. The check valves CV5 and CV6 are respectively installed on the two hydraulic lines branched by the auxiliary hydraulic line MFc. Accordingly, when the inlet valve SI1 is closed, the auxiliary hydraulic line MFc between the master cylinder MC and the hydraulic pump HP1 is shut off. When the inlet valve SI1 is opened, the master cylinder MC and the hydraulic pump And the auxiliary hydraulic line MFc between the hydraulic pressure lines HP1 are connected. At this time, the check valve CV5 prevents the brake fluid from flowing into the low pressure accumulator RS1.

On the other hand, in the hydraulic circuits of the front wheel left wheel FL and the rear wheel right wheel RR, respective components are configured in the same manner as the hydraulic circuits of the front wheel right wheel FR and the rear wheel left wheel RL.

For reference, DP1 and DP2 are high-pressure accumulators.

The inlet valves PC1 to PC4 and the outlet valves PC5 to PC8 in the cut valves SC1 and SC2, the inlet valves SI1 and SI2 and the wheel cylinders WFR, WRL, WFL and WRR in Fig. 1, The motor M that operates the hydraulic pumps HP1 and HP2 is operated by an electronic control unit (ECU) 10 that performs a control mode such as an ESC mode to increase, decrease, or maintain the braking pressure of the wheel . The electronic control unit electronic control unit (ECU) 10 includes cut valves SC1 and SC2, inlet valves SI1 and SI2, and wheel cylinders WFR, WRL, WFL, and WRR via braking pressure regulator 20, And controls the operation of the inlet valves PC1 to PC4 and the outlet valves PC5 to PC8 and the motor M of the engine.

The wheel speed sensors WS1 to WS4 provided on the front left and right wheels FL and FR and the rear wheel left and right wheels RL and RR are electrically connected to the electronic control unit (ECU) 10 so as to provide the detected wheel speed Lt; / RTI >

In addition, various sensors for judging the behavior of the vehicle are connected to the electronic control unit 10, and in particular, a steering angle sensor 11 installed at a steering shaft of the steering wheel and detecting a steering angle and a steering angle speed according to a steering operation of a driver, A yaw rate sensor 12 for detecting the turning speed of the vehicle, a lateral acceleration sensor 13 for detecting the lateral acceleration of the vehicle, and an acceleration pedal sensor 13 for detecting the acceleration will of the driver are electrically connected. At this time, the electronic control unit 10 sets the turning degree and the turning direction of whether the vehicle is turning slowly or swiftly to any one of the output values of the steering angle sensor 11, the yaw rate sensor 12 and / or the lateral acceleration sensor 13 And is recognized by the voltage level and the sign type of one or a combination of output values.

For example, in the present invention, the turning degree and the turning direction of the vehicle are recognized according to the voltage level and sign shape of the lateral acceleration value detected through the lateral acceleration sensor 13.

The electronic control unit 10 obtains vehicle speed information from each of the wheel speed sensors WS1 to WS4 and obtains steering angle and steering angle speed information from the steering angle sensor 11 and obtains yaw rate information from the yaw rate sensor 12, Obtains the lateral acceleration information from the acceleration sensor 13, acquires the acceleration intention information of the driver from the accelerator pedal sensor 14, and performs braking pressure control to improve the turning stability of the vehicle using the respective information , And performs ESC control to prevent understeer or oversteer.

The electronic control unit 10 determines whether or not the spinning of the turning inner side and the turning wheel is performed when the vehicle is turning when the vehicle is running. When the spin is generated only on the inner turning wheel without generating the spin on the turning outer side wheel, To increase the braking pressure on the turning inner wheel (see arrows in Fig. 3).

The electronic control unit 10 calculates the slip amount of the inner wheel and the slip amount of the outer wheel on the basis of the wheel speed of each wheel and determines whether the slip amount of the outer wheel of the turn is smaller than the predetermined amount of slip for determining the occurrence of spin, Is larger than the preset slip amount, it is determined that the turning inner wheel is spinning. In addition, the spin generation judgment can be judged by a function of inputting the driver acceleration will, yaw rate, lateral acceleration, speed difference between the inner wheel of the turning wheel and the outer wheel.

On the other hand, the braking control of the electronic control unit 10 for the turning inner wheel is performed when the difference between the yaw rate demanded by the driver and the actual yaw rate detected by the yaw rate sensor 11 is equal to or less than a predetermined value. That is, braking control is first performed on the turning inner wheel before the vehicle attitude control (ESC control) is performed. If the turning stability is not ensured by such braking control, the difference between the yaw rate demanded by the driver and the actual yaw rate gradually increases, and when the yaw rate difference exceeds a predetermined value, the ESC control is finally entered.

4 is a control flowchart for a method of controlling a vehicle turning control apparatus according to an embodiment of the present invention.

Referring to Fig. 4, the electronic control unit 10 detects the lateral acceleration of the vehicle through the lateral acceleration sensor (100).

The electronic control unit 10 compares the lateral acceleration detected through the lateral acceleration sensor with a predetermined lateral acceleration to determine whether the vehicle is turning (110). At this time, if the lateral acceleration detected through the lateral acceleration sensor is equal to or greater than a preset lateral acceleration, it is determined that the vehicle is turning.

If it is determined in the operation mode 110 that the vehicle is turning, the electronic control unit 10 senses the spin of the turning inner wheel (120).

After sensing the spin of the turning inner wheel, the electronic control unit 10 determines whether a spin has occurred in the turning inner wheel (130). At this time, the electronic control unit 10 detects the wheel speed of the inner wheel of the turning wheel and the wheel speed of the outer wheel of the turning respectively, and calculates the wheel slip amount of the turning inner wheel and the wheel slip amount And if the calculated wheel slip amount of the outer wheel is smaller than a preset slip amount and the wheel slip amount of the calculated inner wheel is larger than a preset slip amount, it can be determined that the spin occurred in the inner wheel of the turning wheel.

On the other hand, when it is determined that the spin has occurred in the turning inner wheel as a result of the determination in the operation mode 130, the electronic control unit 10 brakes the turning inner wheel by providing the braking pressure to the turning inner wheel through the braking pressure adjusting unit 20 (140).

On the other hand, as described above, the braking control for the above-mentioned turning inner wheel is performed when the difference between the yaw rate demanded by the driver and the actual yaw rate detected by the yaw rate sensor 11 is equal to or less than a preset value, When the difference between the required yaw rate and the actual yaw rate exceeds a predetermined value, the ESC control is started. At this time, the ESC control adjusts the braking force of the wheel according to whether the vehicle behavior is the overtearier or the understeer, and adjusts the engine driving force to secure the turning stability of the vehicle.

As described above, when a spin is generated in the turning inner wheel at the turning of the vehicle, the understeer tendency of the vehicle is prevented by braking the turning inner wheel before reaching the limit of the road surface where the turning inner wheel can be held, Unnecessary engine control for reducing the engine driving force can be prevented, and acceleration performance can be ensured.

MC: master cylinder
PC1 ~ PC4: Normally open type inlet valve
PC5 to PC8: Normally closed type outlet valve
WS1 to WS4: Wheel speed sensor 10: Electronic control unit (ECU)
11: steering angle sensor 12: yaw rate sensor
13: lateral acceleration sensor 14: accelerator pedal sensor

Claims (5)

When the vehicle is turning, the wheel speed of the inner wheel and the wheel speed of the outer wheel are respectively detected,
The wheel slip amount of the turning inner wheel and the wheel slip amount of the turning outer wheel are respectively calculated,
Determining whether or not the spin of the turning inner wheel is generated by comparing the calculated wheel slip amount of the outer wheel with the calculated slip amount of the wheel inner wheel,
A yaw rate of the vehicle is detected when it is determined that a spin has occurred in the turning inner wheel,
Determines whether a difference between the detected yaw rate and a yaw rate demanded by the driver is smaller than a predetermined yaw rate,
If the difference between the detected yaw rate and the yaw rate demanded by the driver is smaller than a preset yaw rate, the turning inner wheel is braked,
Detecting a yaw rate of the vehicle after braking the turning inner wheel,
And if the difference between the detected yaw rate and the yaw rate demanded by the driver is greater than a predetermined yaw rate, stopping braking on the turning inner wheel and starting the vehicle attitude control. delete When the vehicle is turning, the wheel speed of the inner wheel and the wheel speed of the outer wheel are respectively detected,
Calculating a wheel slip amount of the turning inner wheel and a wheel slip amount of the turning outer wheel based on the detected wheel speeds,
If the calculated wheel slip amount of the outer wheel is smaller than a preset slip amount and the calculated wheel slip amount of the inner wheel is larger than the preset slip amount,
And braking the turning inner wheel when a spin is generated in the turning inner wheel. When the vehicle turns, it is determined whether or not a spin of the turning inner wheel is generated,
Wherein when a spin is generated in the turning inner wheel, a yaw rate of the vehicle is detected,
And when the difference between the detected yaw rate and the yaw rate demanded by the driver is smaller than a predetermined yaw rate, braking the turning inner wheel. When the vehicle turns, it is determined whether or not a spin of the turning inner wheel is generated,
When the spin is generated in the turning inner wheel, the turning inner wheel is braked,
Detecting a yaw rate of the vehicle after braking the turning inner wheel,
When the difference between the detected yaw rate and the yaw rate demanded by the driver is greater than a predetermined yaw rate, stopping braking on the turning inner wheel and starting the vehicle attitude control.

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