KR101245100B1 - Smart cruise control system and control method thereof - Google Patents

Abstract

The present invention is a wheel speed detection unit for detecting the speed of the wheel of the vehicle; A steering angle detector for detecting a steering angle of the vehicle; A yaw rate detector for detecting a turning degree of the vehicle; Acquire yaw rate and original yaw rate for each steering state, biased brake pressure, and calculate the deviation between the original yaw rate and yaw rate during turning braking of the vehicle, and look up for the required biased brake pressure for each steering state and deviation And a microcontroller unit for creating a table and controlling turning braking of the vehicle using the lookup table.
The present invention utilizes the yaw rate to generate the target wheel pressure so that the driver can feel the same turning feeling regardless of turning driving situation or turning braking situation.

Description

Smart cruise control system and its control method {SMART CRUISE CONTROL SYSTEM AND CONTROL METHOD THEREOF}

The present invention relates to a smart cruise control system and a control method for allowing a driver to feel the same turning feeling in a turning driving situation or a turning braking situation.

Recently, when the driver sets the vehicle speed to a certain speed, a cruise control system has been developed to maintain the speed of the vehicle according to the external road conditions without pressing the brake or the accelerator pedal.

Furthermore, in recent years, a smart cruise control (SCC) system that includes a radar in a vehicle and detects the distance to the vehicle ahead and controls the throttle and the brake to decelerate or accelerate to maintain a safe distance from the vehicle ahead. This was developed.

During the control of smart cruise control, especially in braking situations, the target pressure of the wheel is generated to automatically perform braking. Currently, the same target pressure is generated regardless of whether the vehicle is turning or driving straight. However, it is necessary to adjust the pressure of the wheel in order to accurately drive in the direction required by the driver during the turning.

The present invention provides a smart cruise control system and a method of controlling the same to make the driver feel the same turning direction or turning braking situation by generating the target wheel pressure using the yaw rate.

Smart cruise control system according to an aspect of the present invention includes a wheel speed detector for detecting the speed of the wheel of the vehicle; A steering angle detector for detecting a steering angle of the vehicle; A yaw rate detector for detecting a turning degree of the vehicle; Acquire yaw rate and original yaw rate for each steering state, biased brake pressure, and calculate the deviation between the original yaw rate and yaw rate during turning braking of the vehicle, and look up for the required biased brake pressure for each steering state and deviation And a microcontroller unit for creating a table and controlling turning braking of the vehicle using a lookup table.

In addition, the microcontroller unit calculates the original yaw rate by using Equation 1 below.

[Equation 1]

(Wherein, l _f is the distance to the center of gravity from the front axle, l _r is the distance to the center of gravity from the front axle, C _αf is rigid (Stiffness) of the front wheel cornering, C _αr is rigid (Stiffness) of the front wheel cornering, L Where l _f + l _r , m is the mass, δ is the steering angle, and V is the wheel speed in the longitudinal direction.)

The apparatus may further include a braking force adjusting unit that controls the brake hydraulic pressure supplied to the wheel cylinder according to the braking signal output from the microcontroller unit.

The apparatus may further include a driver interface configured to communicate with the driver by initiating the adaptive cruise control and connecting the mode and the control situation with the driver.

The control method of the smart cruise control system according to an aspect of the present invention obtains the yaw rate and the original yaw rate for each steering state, braking pressure during turning braking of the vehicle; Calculate a deviation between the original yaw rate and the yaw rate; Create a look-up table for the required braking pressures for each steering condition and deviation; The lookup table is used to control the turning braking of the vehicle.

In addition, the original yaw rate is calculated using Equation 1 below.

[Equation 1]

(Wherein, l _f is the distance to the center of gravity from the front axle, l _r is the distance to the center of gravity from the front axle, C _αf is rigid (Stiffness) of the front wheel cornering, C _αr is rigid (Stiffness) of the front wheel cornering, L Where l _f + l _r , m is the mass, δ is the steering angle, and V is the wheel speed in the longitudinal direction.)

The present invention utilizes the yaw rate to generate the target wheel pressure so that the driver can feel the same turning feeling regardless of turning driving situation or turning braking situation.

1 is a control block diagram of a smart cruise control system according to an embodiment of the present invention.
2 is a flowchart illustrating a control method of a smart cruise control system according to an embodiment of the present invention.

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

1 is a control block diagram of a smart cruise control system according to an embodiment of the present invention.

As shown in FIG. 1, the smart cruise control system 100 includes a sensor module 110, a micro controller unit 120 (hereinafter referred to as an MCU), a braking force control unit 130, and an engine driver ( 140, the electronic parking brake device 150, and the driver interface 160.

The sensor module 110 includes a front sensor 111, a camera sensor 112, a road speed sensor 113, a wheel speed detector 114, and a steering angle detector 115.

The front sensor 111 detects the relative speed and the relative distance of the object in front of the vehicle.

The camera sensor 112 detects the type of the object in front of the vehicle.

The road speed sensor 113 is a sensor for recognizing the safety speed of the road and the speed limit of the road. The road speed sensor 113 enters a speed limit section and a curve using a GPS (Global Positioning System), navigation, and a speed limit traffic sign recognition camera. You can recognize the safety speed and the speed limit of the road with the access section.

The wheel speed detection unit 114 is installed on the wheel of the front left wheel of the vehicle to detect the speed of the left front wheel, the FL wheel speed sensor installed on the wheel of the right front wheel, and the FR wheel speed sensor to detect the speed of the right front wheel, RL wheel speed sensor is installed on the wheel to detect the speed of the left rear wheel, RR wheel speed sensor is installed on the wheel of the right rear wheel to detect the speed of the right rear wheel , each wheel speed sensor of the wheel speed detector 114 The speed of the detected wheel is transmitted to the MCU 20.

The steering angle sensor 115 detects a steering degree of the vehicle and transmits the steering angle to the MCU 20. The steering angle detector 115 is mounted at a lower portion of the steering wheel, and detects the steering angle of the steering wheel and transmits the steering angle to the MCU 120 when the steering wheel is steered as much as the driver operates when the steering wheel is rotated. The steering angle detector 115 also detects a steering speed and a steering direction of the handle. Steering angle detection unit 115 is the optical element type when steering the sensor's slit plate rotates while passing or blocking the light of the optical element as the change of the voltage is generated and the MCU 20 receives the steering speed, steering direction and steering angle of the handle Detect.

Yaw rate detection unit 116 detects the degree of turning of the vehicle and transmits to the MCU (120). The yaw rate detector 116 electronically detects the yaw moment of the vehicle while the plate fork causes a vibration change when the vehicle rotates about the vertical axis, that is, rotates about the Z axis direction. The yaw moment is the force to move toward the inner and outer wheels when the front and rear of the car body turn left or right or turn. The yaw rate detection unit 116 has a cesium crystal element therein, and when the element rotates while the vehicle moves, the element rate rotates while the element itself rotates.

The MCU 120 controls the overall operation of the smart cruise control system. The MCU 120 acquires the yaw rate and the original yaw rate according to the steering state, the braking pressure, and the original yaw rate when turning the vehicle. The yaw rate between the rate and the yaw rate is calculated, a lookup table for the required braking pressure for each steering state and the deviation is generated, and the turning braking of the vehicle is controlled using the lookup table.

The MCU 120 first measures the original yaw rate in the normal state based on the speed of the vehicle detected through the wheel speed detector 114 and the steering angle detected by the steering angle detector 115 as shown in Equation 1 below. Calculate the (Yaw Rate_Original) value.

 [Equation 1]

 here,

_f is the distance from the front axle to the center of gravity,

_r is the distance from the front wheel axle to the center of gravity,

C _αf is the stiffness of the front wheel cornering,

C _αr is the stiffness of the front wheel cornering.

L is l _f + l _r ,

m is mass

δ is the steering angle

V means the wheel speed in the longitudinal direction.

[Equation 1] is valid in the driving state, Yaw generation in the braking situation during the smart cruise control control is generated larger or smaller depending on the characteristics of the vehicle. Accordingly, in the present invention, the yaw rate is generated as shown in [Equation 1] by causing the braking to occur so that the same yaw rate is generated whether the driver is turning or turning braking. The driver can be comforted.

The braking force control unit 130 controls the brake hydraulic pressure supplied to the wheel cylinder according to the braking signal output from the MCU 120.

The engine driver 140 increases the speed of the vehicle by controlling the acceleration driving force of the vehicle.

The electronic parking brake device 150 maintains a braking force when the vehicle is parked.

The driver interface 160 connects and communicates the start and mode of the adaptive cruise control and the control situation with the driver.

2 is a flowchart illustrating a control method of a smart cruise control system according to an embodiment of the present invention.

First, the MCU 120 acquires a yaw rate for each steering state, a bias pressure, and an original yaw rate — original yaw rate — in operation 210. At this time, the MCU 120 is based on the original yaw rate based on the vehicle's speed detected through the wheel speed detector 114 and the steering angle detected by the steering angle detector 115 as shown in Equation 1 below. Yaw Rate) value is calculated.

[Equation 1]

here,

_f is the distance from the front axle to the center of gravity,

_r is the distance from the front wheel axle to the center of gravity,

C _αf is the stiffness of the front wheel cornering,

C _αr is the stiffness of the front wheel cornering.

L is l _f + l _r ,

m is mass

δ is the steering angle

V means the wheel speed in the longitudinal direction.

Next, the controller 20 calculates a yaw rate deviation (Delta Yaw Rate) by using Equation 2 below (220).

&Quot; (2) "

Delta Yaw Rate = Yaw Rate_Original-Yaw Rate

Thereafter, the controller 20 creates a look-up table for the required braking pressure for each steering state and for each Delta Yaw Rate (230).

Next, the control unit 20 controls the turning braking operation by using the created lookup table (240).

100: smart cruise control system 110: sensor module
111: front sensor 112: camera sensor
113: road speed sensor 114: wheel speed detection unit
115: steering angle detector 116: yaw rate detector
120: microcontroller unit (MCU) 130: braking force control unit
140: engine driving unit 150: electronic parking brake device
160: driver interface

Claims (6)

A wheel speed detector for detecting a speed of a wheel of the vehicle;
A steering angle detector for detecting a steering angle of the vehicle;
A yaw rate detector for detecting a turning degree of the vehicle;
The yaw rate for each steering state, the braking pressure, and the original yaw rate are obtained when the vehicle brakes, and the deviation between the original yaw rate and the yaw rate is calculated, and the steering state and the deviation need. A microcontroller unit for creating a lookup table for braking pressure and for controlling turning braking of the vehicle using the lookup table ;
The micro controller unit calculates the original yaw rate by using Equation 1 below.
[Equation 1]

(Wherein, l _f is the distance to the center of gravity from the front axle, l _r is the distance to the center of gravity from the front axle, C _αf is rigid (Stiffness) of the front wheel cornering, C _αr is rigid (Stiffness) of the front wheel cornering, L Where l _f + l _r , m is the mass, δ is the steering angle, and V is the wheel speed in the longitudinal direction.)

delete The method of claim 1,
Smart cruise control system further comprising a braking force control unit for controlling the brake hydraulic pressure supplied to the wheel cylinder in accordance with the braking signal output from the microcontroller unit. The method of claim 1,
A smart cruise control system further comprising a driver interface that initiates adaptive cruise control and communicates with the driver in mode and control situations. Acquire yaw rate and original yaw rate for each steering state, braking pressure during turning braking of the vehicle;
Calculate a deviation between the original yaw rate and the yaw rate;
Create a lookup table for the required braking pressures for each of the steering states and for the deviations;
By controlling the turning braking of the vehicle using the lookup table ,
The control method of the smart cruise control system for calculating the original yaw rate using the following [Equation 1].
[Equation 1]

(Wherein, l _f is the distance to the center of gravity from the front axle, l _r is the distance to the center of gravity from the front axle, C _αf is rigid (Stiffness) of the front wheel cornering, C _αr is rigid (Stiffness) of the front wheel cornering, L Where l _f + l _r , m is the mass, δ is the steering angle, and V is the wheel speed in the longitudinal direction.)
delete

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