TWI633030B - Vehicle automatic lane following control system and method - Google Patents

Abstract

The present invention provides a vehicle automatic lane following control system and method, including an image sensor, a steering angle sensor, an inertial measurement unit, a vehicle speed sensor, an electronic device and a controller. The image sensor generates a lane information; the steering angle sensor generates a steering angle information; the inertia measuring unit generates an acceleration information, a yaw rate information and a tilt angle information; the vehicle speed sensor generates a Vehicle speed information; the controller is electrically connected to the image sensor, the steering angle sensor, the inertial measurement unit, the electronic device and the vehicle speed sensor, and the controller receives a digital map information, the lane The information, the steering angle information, the acceleration information, the yaw rate information, the tilt angle information, and the vehicle speed information are used to calculate one of the steering wheel compensation angle information.

Description

Vehicle automatic lane following control system and method

The present invention relates to a vehicle automatic lane following control system and method, and more particularly to a vehicle automatic lane following control system and method considering the inclination angle of the vehicle and the slope angle of the lane.

According to statistics from the US Department of Transportation, the collision caused by vehicles deviating from the lane accounted for 51% of all collisions. In another report of the US Interstate Highway and Transportation Association, the vehicle deviated from the lane. The mortality rate accounts for 58% of all traffic accident deaths. It can be seen that the deviation of the vehicle from the lane leads to a high probability of a collision accident and is a traffic accident that often leads to death.

Therefore, the automobile manufacturer designs a Lane Following Control (LFC), and the central control system of the lane following control system obtains the lane geometric information with respect to the vehicle via the sensing system, and maintains the vehicle in the center of the lane by controlling the steering system. On the line, it prevents the vehicle from deviating from the lane, thus avoiding the occurrence of traffic accidents and reducing the burden on the driver.

The existing lane following control system mostly uses the image sensor to detect the lane line. When the vehicle is traveling in a flat lane, the lane following control system can successfully control the steering wheel of the vehicle, so that the vehicle maintains two lanes on both sides. Travel between the lines.

However, when the vehicle generates a Roll Angle while traveling, or when the lane has a Bank Angle, the lane following control system may have the slope due to the inclination of the vehicle or the lane. As the steering wheel deviates from control, the vehicle may not be able to effectively maintain travel between the two lane lines.

In the patent of Chinese Patent No. CN101778753B, an operating method and system for supporting lane keeping of a vehicle is disclosed, the main purpose of which is to prevent the vehicle from shifting the lane when passing through a curve, by predicting the future trajectory and location of the vehicle. The desired lane position is compared to determine the steering of the vehicle. However, this patent does not consider the tilt angle of the vehicle, and the method of operation used may still be unable to maintain the vehicle between lane lines.

Therefore, as shown in FIG. 6, it is necessary to consider a situation in which the vehicle 60 hits a tilt angle 61 or a lane has a slope angle during driving, and improves the existing lane following control system, so that the lane following control system is on the steering wheel control. Without deviating too much, the vehicle 60 is maintained between the two lanes to reduce accidental casualties caused by fatigue or deviation from the lane.

The purpose of the present invention is to create a vehicle automatic lane following control system that adjusts the steering angle of the steering wheel of the vehicle with reference to the inclination angle of the vehicle and the slope angle of the lane, and effectively controls the vehicle in the lane line. between.

According to the above objective, the present invention provides a vehicle automatic lane following control system, comprising: an image sensor that senses one lane of a vehicle to generate one lane information; and a steering angle sensor that senses one of the vehicles a steering angle of the steering wheel to generate a steering angle information; an inertia measuring unit sensing one of the acceleration of the vehicle, a yaw rate and a tilt angle to generate an acceleration information, a yaw rate information and a tilt angle information a vehicle speed sensor that senses the vehicle speed to generate a vehicle speed information; an electronic device that receives a digital map information; a controller that electrically connects the image sensor, the steering angle sensor, and the An inertial measurement unit, the vehicle speed sensor and the electronic device, and the controller receives the digital map information, the lane information, the steering angle information, the acceleration information, the yaw rate information, the tilt angle information, and the The speed information is used to calculate the compensation angle information of one of the steering wheels.

Another object of the present invention is to create a vehicle automatic lane following control method, by which the compensation angle information of the steering wheel of the vehicle can be calculated, and according to the inclination angle information of the vehicle and the slope angle information of the lane, Control the vehicle on the centerline of the two lane line.

According to the above objective, the present invention provides a vehicle automatic lane following control method, comprising the steps of: sensing a two lane line of a lane of a vehicle through an image sensor to generate a lane information, and outputting the lane information to a a central line calculation unit; receiving the lane information through a central line calculation unit to calculate a central line information, and outputting the central line information; according to a vehicle yaw rate information, acceleration information, vehicle speed information, and a steering wheel of the vehicle Calculating a predicted offset trajectory information of the vehicle according to a steering angle; calculating a lateral displacement area of the vehicle according to the predicted offset trajectory information of the vehicle and the central line information; calculating an offset area according to the lateral displacement area, And calculating a compensation angle information of the steering wheel of the vehicle; and correcting the compensation angle information of the steering wheel of the vehicle by referring to a slope angle information of the lane, a tilt angle information of the vehicle, and a comparison table.

The advantage of the present invention is that: further referring to the inclination angle of the vehicle and the slope angle of the lane, the vehicle automatic lane following control system can maintain the vehicle in the center of the second lane without excessive deviation from the steering wheel control. Drive online to reduce accidental casualties caused by fatigue or deviation from the driveway.

Referring to FIG. 1 , the vehicle automatic lane following control system 10 of the present invention comprises an image sensor 11 , a control unit 12 , a steering angle sensor 13 , and a steering angle sensor 13 . An Inertial Measurement Unit (IMU) 14 and a Vehicle Speed Sensor 15 are provided. The controller 12 includes a Centerline Compute 121, a Predicted Trajectory Compute 122, a Lateral Displacement Area Compute 123, and a Steering Angle Computation Unit (Steering Angle) Compute) 124.

The image sensor 11 is electrically connected to the controller 12, and the controller 12 is electrically connected to the steering angle sensor 13, the inertia measurement unit 14, and the vehicle speed sensor 15, respectively. Further, the central line calculation unit 121 of the controller 12 is electrically connected to the image sensor 11 , and the predicted trajectory calculation unit 122 is electrically connected to the steering angle sensor 13 , the inertial measurement unit 14 and the sense of speed Detector 15. The lateral displacement area calculation unit 123 is electrically connected to the center line calculation unit 121 and the predicted trajectory calculation unit 122. The steering angle calculation unit 124 is electrically connected to the lateral displacement area calculation unit 123 and the inertia measurement unit 14.

The image sensor 11 is configured to sense a two-lane line of one lane to generate a lane information, and output the lane information to the central line calculating unit 121, and the central line calculating unit 121 calculates the lane information according to the received lane information. a central line for outputting a central line information, the central line is located between the two lane lines, and the central line is a central imaginary line between the two lane lines where the vehicle is located, and the central line information is output to the horizontal line Displacement area calculation unit 123. The vehicle automatic lane following control system 10 of the present invention determines that the vehicle is shifted to the left or to the right based on the center line information, and then adjusts the offset of the vehicle. In addition, the steering angle sensor 13 senses a steering angle of the steering wheel of the vehicle to generate a steering angle information, and outputs the steering angle information to the predicted trajectory calculating unit 122.

The inertia measurement unit 14 is a device for measuring a Yaw rate information of the vehicle and an acceleration information. Generally, the inertia measurement unit 14 includes a three-axis gyroscope and three directions. The accelerometer can measure a yaw rate and an acceleration of the object in three-dimensional space, and thereby calculate the attitude of the object. In the present creation, the inertia measurement unit 14 is disposed on the vehicle, and can output the acceleration information of the vehicle and the yaw rate information to the predicted trajectory calculation unit 122. In addition, the inertial measurement unit 14 further outputs a tilt angle information of the vehicle to the steering angle calculation unit 124, and the inventive automatic lane following control system 10 corrects the steering angle of the steering wheel according to the tilt angle information of the vehicle. .

The vehicle speed sensor 15 is configured to sense the vehicle speed of the vehicle to output a vehicle speed information to the predicted trajectory calculation unit 122. Therefore, based on the steering angle information of the steering wheel, the acceleration information of the vehicle, the yaw rate information, and the vehicle speed information, the predicted trajectory calculation unit 122 may calculate a predicted offset trajectory information of the vehicle, and The predicted offset trajectory information is output to the lateral displacement area calculation unit 123.

The lateral displacement area calculation unit 123 calculates a lateral displacement area of the vehicle based on the calculated central line information and the predicted offset trajectory information, and then outputs the lateral displacement area to the steering angle calculation unit 124. How to calculate the lateral displacement area will be further explained in the following paragraphs.

The steering angle calculation unit 124 is further connected to an electronic device 16, which is preferably a Global Positioning System (GPS), or the electronic device 16 can be a wireless network card that can be wirelessly connected to the Internet. The road downloads a digital map information, which is not limited here. The electronic device 16 can output the digital map information to the steering angle calculation unit 124. Through the digital map information, the steering angle calculation unit 124 can obtain a bank angle information of the lane. In addition, the steering angle calculation unit 124 receives a lookup table stored in a memory 125 inside the automatic lane following control system 10, and the memory 125 can be disposed in the steering angle calculation unit. The inside of the 124 is disposed outside the steering angle calculation unit 124, and is not limited herein. The comparison table stores the vehicle speed information, the slope angle information of the lane, or the tilt angle information of the vehicle and the relationship between the steering angle information of the steering wheel.

The steering angle calculation unit 124 calculates a compensation angle information of the steering wheel of the vehicle according to the lateral displacement area. In addition, the steering angle calculation unit adjusts the compensation angle information of the vehicle according to the steering angle information of the steering wheel, the slope angle information of the lane, and the vehicle speed information. Based on the compensation angle information, the vehicle automatic lane following control system 10 corrects the steering angle of the steering wheel to maintain the vehicle between the lane lines. How to create this comparison table will be further explained in the following paragraphs.

The vehicle automatic lane following control system 10 of the present invention takes the inclination angle information of the vehicle and the slope angle information of the lane into consideration, thereby reducing the error of the vehicle offset calculation, thereby effectively controlling the vehicle Between the two lane lines.

In fact, referring to FIG. 2, the driver visually observes that the offset path of the vehicle 20 is the trajectory 21, and the predicted trajectory calculated by the predicted trajectory calculation unit of the present creation is the trajectory 22 of the vehicle. It can be seen that there is an error between the trajectory 21 of the offset path of the vehicle 20 and the trajectory 22 of the predicted offset trajectory of the vehicle 20, and therefore the predicted offset according to the vehicle 20 is required. This trajectory 22 of the trajectory corrects the direction of the vehicle.

Referring to FIG. 3, a first trajectory 31 is the central line of the two lane lines, and a first function (func1) is a mathematical function representing the first trajectory, and a second trajectory 32 is a lane following control of the creation. The system calculates the predicted offset trajectory information of the vehicle 30 offset, and a second function (func2) is a mathematical function representing the second trajectory 32. The first point (d1) is the intersection of the horizontal extension line of the front end of the vehicle 30 and the center line, the horizontal extension line of the front head is perpendicular to the center line; the second point (d2) is the second track 32 and The intersection of the central line; the third point (d3) is a forward view point, and the distance between the front end of the vehicle 30 and the third point (d3) is a look ahead distance, and the forward view distance is Vehicle speed (V _car ) * time (t), which is a fixed value, the faster the vehicle speed, the longer the required forward distance, which is 2 in an embodiment of the present creation. The intersection of the horizontal extension line of the third point (d3) and the first trajectory 31 is a fourth point (d4), and the horizontal extension line of the third point (d3) is perpendicular to the central line (x').

The first area (A) is an area between the first track 31 and the second track 32 between the second point (d2) and the fourth point (d4); the second area (B) is the first area An area between a track 31 and the second track 32 between the first point (d1) and the second point (d2), the formula of the first area (A) and the second area (B) is as follows :

The formula for the first area (A) is ,

The formula of the second area (B) is ,

The offset area is the second area (B) minus the first area (A). If the offset area is >0, indicating that the second area (B) is greater than the first area (A), the steering wheel of the vehicle should Turning to the right, conversely, if the offset area is <0, indicating that the first area (A) is greater than the second area (B), the steering wheel of the vehicle 30 should be turned to the left. By embedding the above calculation formula into the steering angle calculation unit 124 shown in FIG. 1, the steering angle calculation unit 124 can calculate the steering left or right and the compensation angle required for the steering wheel.

Table 1 is the average speed (Avg. Speed) of the vehicle, the inclination angle of the lane or the slope angle of the lane (Avg. Roll Angle/Bank Angle) and the steering angle of the steering wheel (Steaing Wheel Angle, SWA) Look up table between:

Table 1

4 is a graph of the tilt angle of the vehicle or the slope angle of the lane and the steering angle of the steering wheel. According to Table 1 and Figure 4, the two broken lines are the curves of the inclination angle and the slope angle, and the two solid lines are the linear regression curves obtained for the inclination angle and the slope angle. Using a linear regression method, the vehicle can be calculated. When the tilt angle or the slope angle of the lane is a few degrees, what is the compensation angle information required for the steering angle of the steering wheel. In statistics, linear regression is a regression analysis that uses the least squares function of linear regression equations to model the relationship between one or more independent variables and dependent variables. Therefore, the vehicle automatic lane following control system 10 of the present invention calculates the compensation angle information of the steering wheel and refers to the graph drawn by the comparison table and the linear regression method to find out that the vehicle needs to be at the vehicle speed. The compensation angle information is fine-tuned, and the compensation angle information is further corrected so that the vehicle can be continuously maintained between the two lane lines.

Referring to FIG. 5, the automatic lane following control method of the present invention includes the following steps. In step S501, a two-lane line on the road surface is sensed through an image sensor, and one lane of information generated by the sensing is output to a central line calculation unit. In order to keep a vehicle between the two lane lines, it is necessary to know the position of the two lane lines first. The automatic lane following control system of the present invention can refer to the two lane lines, and knows to control a steering wheel to turn left or turn. right.

In step S502, the central line calculation unit receives the lane information to calculate a central line to generate a central line information. Based on the central line, the vehicle determines whether the vehicle is currently a left offset or a right offset, and further calculates a lateral displacement area of the vehicle according to the central line information, thereby knowing that the steering wheel is to be turned left or right. .

In step S503, a yaw rate information of the vehicle, an acceleration information, a vehicle speed information, and a steering angle information of the steering wheel of the vehicle are obtained to calculate a predicted offset trajectory information of the vehicle. Obtaining the yaw rate information of the vehicle and the acceleration information through an inertial measurement unit, the vehicle speed information of the vehicle can be obtained through a vehicle speed sensor, and the steering of the steering wheel can be obtained through a steering angle sensor. Angle information, so the predicted offset trajectory information of the vehicle can be calculated.

In step S504, the lateral displacement area of the vehicle is calculated by a lateral displacement area calculation unit according to the predicted offset trajectory information of the vehicle and the central line information. Through the lateral displacement area, it is determined whether the vehicle is offset to the left or to the right, and a compensation angle information of the steering wheel of the vehicle can be further calculated.

In step S505, an offset area is calculated according to the lateral displacement area, thereby obtaining the compensation angle information of the steering wheel. Calculating the lateral displacement area (a first area and a second area) of the vehicle on the left and right sides of the center line, the offset area being equal to the second area minus the first area, if the offset area is > 0, the steering wheel controls the vehicle to turn to the right, and if the offset area is <0, the steering wheel controls the vehicle to turn left. The calculation formula of the lateral displacement area is as shown above, and will not be described herein.

In step S506, according to the compensation angle information of the steering wheel calculated in step S505, and referring to a slope angle information of the lane of the digital map information, a tilt angle information of the vehicle, and a comparison table, the correction is performed. The compensation angle information of the steering wheel of the vehicle. The compensation angle information calculated in step S505 is assumed to be that the vehicle has no inclination and the lane has no such slope angle. After calculating the compensation angle information, according to the actual inclination angle of the vehicle and the slope angle of the lane Referring to the comparison table, it is found out what the compensation angle information needs to be fine-tuned when the vehicle is at the vehicle speed, and the compensation angle information is further corrected to maintain the vehicle traveling on the central line of the two lane line.

By referring to the inclination angle of the vehicle and the slope angle of the lane, the inventive automatic lane following control system and method can more accurately control the steering wheel of the vehicle to turn left or turn when the vehicle is offset. right.

10‧‧‧Vehicle automatic lane following control system
11‧‧‧Image Sensor
12‧‧‧ Controller
121‧‧‧Central Line Calculation Unit
122‧‧‧predicted trajectory calculation unit
123‧‧‧Transverse displacement area calculation unit
124‧‧‧Steering angle calculation unit
125‧‧‧ memory
13‧‧‧Steering angle sensor
14‧‧‧Inertial measurement unit
15‧‧‧Car speed sensor
16‧‧‧Electronic devices
20‧‧‧ Vehicles
21‧‧‧ Track
22‧‧‧ Track
30‧‧‧ Vehicles
31‧‧‧First track
32‧‧‧second track
D1‧‧‧ first point
D2‧‧‧ second point
D3‧‧‧ third point
D4‧‧‧ fourth point
A‧‧‧ first area
B‧‧‧Second area
60‧‧‧ Vehicles
61‧‧‧Tilt angle

FIG. 1 is a system block diagram of the vehicle automatic lane following control system of the present invention. 2 is a schematic diagram of a vehicle visual trajectory and a predicted trajectory. Figure 3 is a schematic illustration of the lateral displacement area of the vehicle. 4 is a graph showing the relationship between the inclination angle of the vehicle or the slope angle of the lane and the steering angle of the steering wheel. FIG. 5 is a flow chart showing the steps of the automatic vehicle lane following control method of the present invention. Figure 6 is a schematic illustration of the tilt angle of the vehicle.

Claims (10)

A vehicle automatic lane following control system includes: an image sensor that senses a two lane line of a lane of a vehicle to generate one lane information; and a steering angle sensor that senses a steering of a steering wheel of the vehicle The angle is used to generate a steering angle information; an inertial measurement unit senses an acceleration of the vehicle, a yaw rate and a tilt angle to generate an acceleration information, a yaw rate information and a tilt angle information; a vehicle that senses a vehicle speed to generate a vehicle speed information; an electronic device that receives a digital map information; and a controller that electrically connects the image sensor, the steering angle sensor, and the inertial measurement unit The vehicle speed sensor and the electronic device to receive the digital map information, the lane information, the steering angle information, the acceleration information, the yaw rate information, the tilt angle information, and the vehicle speed information, and the controller Storing a comparison table; the controller obtains a slope angle information of the lane according to the digital map information, the comparison table includes the vehicle speed information, and the slope angle information of the lane a relationship between the tilt angle information of the vehicle and the steering angle information of the steering wheel; the controller calculates a central line information according to the lane information generated by the image sensor, and according to the steering angle sensor Generating the steering angle information, the acceleration information generated by the inertia measurement unit, the yaw rate information, and the vehicle speed information generated by the vehicle speed sensor, and calculating a predicted offset trajectory information of the vehicle; the controller is configured according to The central line information and the predicted offset trajectory information, calculating a lateral displacement area of the vehicle, and calculating an offset area according to the lateral displacement area to calculate a compensation angle information of the steering wheel; The controller corrects the compensation angle information of the steering wheel of the vehicle according to the slope angle information of the lane, the tilt angle information of the vehicle, and the comparison table. The vehicle automatic lane following control system according to claim 1, wherein the controller comprises: a central line calculating unit electrically connected to the image sensor, receiving the lane information, and calculating the central line information; and a predicted trajectory calculating unit And electrically connecting the steering angle sensor and the inertial measurement unit, respectively receiving the steering angle information, the acceleration information, the yaw rate information, and the digital map information, and calculating the predicted offset trajectory information; a lateral displacement area a calculation unit electrically connecting the central line calculation unit and the predicted trajectory calculation unit, receiving the predicted offset trajectory information and the central line information, and calculating the lateral displacement area; a steering angle calculation unit electrically connecting the inertial sensing unit and The lateral displacement area calculating unit receives the lateral displacement area, and calculates the offset area and the compensation angle information of the steering wheel according to the lateral displacement area, and the steering angle calculation unit further determines the slope angle information according to the lane The tilt angle of the vehicle and the comparison table correct the compensation angle information of the steering wheel. The vehicle automatic lane following control system of claim 2, wherein the lateral displacement area comprises a first area and a second area; wherein the offset area is a difference between the first area and the second area . The vehicle automatic lane following control system of claim 2, further comprising: wherein the electronic device is a global positioning system, the global positioning system receiving the digital map information. The vehicle automatic lane following control system according to any one of the preceding claims, wherein the central line of the two lane line is a first trajectory, and the predicted offset trajectory information is a second trajectory; wherein the offset The area is the difference between the first area and the second area, and the formula of the first area and the second area is: Wherein d1 is a first point, the first point is an intersection of a horizontal extension line of the vehicle and the central line, d2 is a second point, and the second point is the second track and the central line The intersection point, d3 is a third point, the third point is a foresight point, d4 is a fourth point, and the fourth point is the intersection point of the horizontal extension line of the third point and the central line, A is The first area, B is the second area, func2(s) is a mathematical function representing the second trajectory, and func1(s) is a mathematical function representing the first trajectory. An automatic lane following control method for a vehicle includes: sensing an image of a lane of a lane of a vehicle through an image sensor to generate a lane information, and outputting the lane information to a central line calculation unit; calculating through a central line The unit calculates a central line information according to the lane information, and outputs the central line information; calculates the vehicle according to a yaw rate information of a vehicle, an acceleration information, a vehicle speed information, and a steering angle of a steering wheel of the vehicle. a predicted offset trajectory information; calculating a lateral displacement area of the vehicle according to the predicted offset trajectory information of the vehicle and the central line information; calculating an offset area according to the lateral displacement area, thereby calculating the vehicle a compensation angle information of the steering wheel; correcting the compensation angle information of the steering wheel of the vehicle according to a slope angle information of the lane, a tilt angle information of the vehicle, and a comparison table; wherein the comparison table includes the vehicle speed information, The slope angle information of the lane, the tilt angle information of the vehicle, and the steering angle information of the steering wheel The list of relationship. The vehicle automatic lane following control method according to claim 6, wherein in the step of calculating the predicted offset trajectory information of the vehicle, the yaw rate information of the vehicle, the acceleration information, and the inertial computing unit are measured. The tilt angle information. The vehicle automatic lane following control method according to claim 6, wherein the lateral displacement area includes a first area and a second area; wherein the offset area is calculated according to the lateral displacement area, thereby calculating the vehicle In the step of compensating the angle information of the steering wheel, calculating the first area and the second area between the central line information and the predicted offset trajectory information, and calculating between the first area and the second area The difference is the offset area; wherein the center line of the two lane line is a first track, and the predicted offset track information is a second track; wherein the formula of the first area and the second area is : Wherein d1 is a first point, the first point is an intersection of a horizontal extension line of the vehicle and the central line, d2 is a second point, and the second point is the second track and the central line The intersection point, d3 is a third point, the third point is a foresight point, d4 is a fourth point, and the fourth point is the intersection point of the horizontal extension line of the third point and the central line, A is The first area, B is the second area, func2(s) represents a mathematical function of the second trajectory, and func1(s) represents a mathematical function of the first trajectory. The vehicle automatic lane following control method according to claim 6, wherein the slope angle information of the lane is obtained according to a digital map information. The vehicle automatic lane following control method according to claim 9, wherein the comparison table is obtained according to the slope angle information of the lane, the tilt angle information of the vehicle, and the vehicle speed, and is calculated by using a linear regression method.