# US 9,517,795 B2 · Lane keeping assist system of vehicle and method of controlling the same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,517,795 B2
- Document ID: US9517795B2
- Status: Granted
- Kind: B2
- Application number: 14/942,432
- Filed: 2015-11-16
- Published: 2016-05-19
- Granted: 2016-12-13
- Earliest claimed: 2014-11-19
- Assignees: Hyundai Mobis Co., Ltd.
- Applicants: HYUNDAI MOBIS Co., Ltd.
- Inventors: Eun Young You; Kyu Hoon Lee
- Web page: https://patentgrep.com/patent/US9517795B2

## CPC

- B62D 15/025: {Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation (B62D1/28 takes precedence)}
- B62D 6/003: {in order to control vehicle yaw movement, i.e. around a vertical axis (B62D6/007 takes precedence)}
- B60R 2300/804: for lane monitoring
- G08G 1/167: {Driving aids for lane monitoring, lane changing, e.g. blind spot detection}
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)
- B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- G08G: TRAFFIC CONTROL SYSTEMS (guiding railway traffic, ensuring the safety of railway traffic B61L; arrangement of road signs or traffic signals E01F9/00; radar or analogous systems, sonar systems, lidar systems specially adapted for traffic control G01S13/91, G01S15/88, G01S17/88; {radar or analogous systems, sonar systems, lidar systems specially adapted for anti-collision purposes G01S13/93, G01S15/93, G01S17/93})

## Abstract

A lane keeping assist system, including: a first calculation unit which calculates left and right position errors of a front portion of the vehicle, a curvature of a lane of the front portion, and a head angle formed based on the lane from a front image of the vehicle captured by an image sensor, and calculates a target yaw rate using the left and right position errors, the curvature of the lane, and the head angle formed based on the lane which are calculated; a second calculation unit which calculates a steering torque control value for driving the calculated target yaw rate using vehicle condition information including front and rear yaw rates of the vehicle sensed by a yaw rate sensor, and a steering angle and a speed of the vehicle; and a steering driving unit which controls steering of the vehicle for keeping a lane.

## Claims

### Claim 1

A lane keeping assist system (LKAS), comprising:
an image sensor configured to capture a front of a vehicle, and obtain a front image of the vehicle;
a first calculation unit configured to calculate left and right position errors of a front portion of the vehicle, a curvature of a lane of the front portion of the vehicle, and a head angle formed based on the lane from the front image of the vehicle, and calculate a steering torque control value of the front portion of the vehicle using the left and right position errors of the front portion of the vehicle, the curvature of the lane of the front portion of the vehicle, the head angle formed based on the lane, which are calculated, and a vehicle speed;
a second calculation unit configured to calculate left and right position errors of a rear portion of the vehicle, and a curvature of a lane of the rear portion of the vehicle, and calculate a steering torque control value of the rear portion of the vehicle using the left and right position errors of the rear portion of the vehicle, the curvature of the lane of the rear portion of the vehicle, the head angle formed based on the lane, which are calculated, and the vehicle speed; and
a steering driving unit configured to determine a final steering torque control value of the vehicle using the steering torque control value of the front portion of the vehicle and the steering torque control value of the rear portion of the vehicle which are calculated, and control steering of the vehicle for lane keeping using the final steering torque control value.

### Claim 2 (depends on 1)

The LKAS of claim 1, wherein the steering driving unit determines a greater value between the steering torque control value of the front portion of the vehicle calculated in the first calculation unit and the steering torque control value of the rear portion of the vehicle calculated in the second calculation unit as the final steering torque control value.

### Claim 3 (depends on 1)

The LKAS of claim 1, wherein the steering driving unit calculates an average value of the steering torque control value of the front portion of the vehicle calculated in the first calculation unit and the steering torque control value of the rear portion of the vehicle calculated in the second calculation unit, and determines the calculated average value as the final steering torque control value of the vehicle.

### Claim 4 (depends on 1)

The LKAS of claim 1, wherein the second calculation unit calculates the left and right position errors and the curvature of the lane of the rear portion of the vehicle using the following equations,
e21=e11−L1*sin ψ
e22=e12−L1*sin ψ
wherein e21 and e22 represent the left and right position errors of the rear portion of the vehicle, e11 and e12 represent the left and right position errors of the front portion of the vehicle, ψ represents the head angle formed based on the lane, and L1 represents a distance which is from one position of the front portion of the vehicle in which an image sensor is installed to another position which is one position of the rear portion of the vehicle.

### Claim 5 (depends on 1)

The LKAS of claim 1, wherein the second calculation unit calculates the left and right position errors and the curvature of the lane of the rear portion of the vehicle using the following equations,
e21=e11−L2*sin ψ
e22=e12−L2*sin ψ
wherein e21 and e22 represent the left and right position errors of the rear portion of the vehicle, e11 and e12 represent the left and right position errors of the front portion of the vehicle, ψ represents the head angle formed based on the lane, and L2 represents a distance which is from one position of the front portion of the vehicle in which an image sensor is installed to another position which is one position located in the rear portion of the vehicle.

### Claim 6 (depends on 1)

The LKAS of claim 1, wherein the second calculation unit determines the curvature of the lane calculated at a position ahead of a distance between one position of the front portion of the vehicle and one position of the rear portion of the vehicle considering the vehicle speed as the curvature of the lane of the rear portion of the vehicle.

### Claim 7

A lane keeping assist system (LKAS), comprising:
an image sensor configured to capture a front of a vehicle, and obtain a front image of the vehicle;
a yaw rate sensor located in a front portion and a rear portion of the vehicle, and configured to sense a front yaw rate and a rear yaw rate of the vehicle;
a first calculation unit configured to calculate left and right position errors of the front portion of the vehicle, a curvature of a lane of the front portion of the vehicle, and a head angle formed based on the lane from the front image of the vehicle, and calculate a target yaw rate using the left and right position errors of the front portion of the vehicle, the curvature of the lane of the front portion of the vehicle, and the head angle formed based on the lane which are calculated;
a second calculation unit configured to calculate a steering torque control value for driving the calculated target yaw rate using vehicle condition information including the front and rear yaw rates of the vehicle, and a steering angle and a speed of the vehicle; and
a steering driving unit configured to control steering of the vehicle for keeping a lane using the calculated steering torque control value.

### Claim 8 (depends on 7)

The LKAS of claim 7, wherein the first calculation unit generates a target trajectory using the left and right position errors of the front portion of the vehicle, the curvature of the lane, and the head angle formed based on the lane, and calculates the target yaw rate for tracking the target trajectory.

### Claim 9 (depends on 7)

The LKAS of claim 7, further comprising:
a steering angle sensor installed in a handle of the vehicle for sensing the steering angle of the vehicle.

### Claim 10 (depends on 7)

The LKAS of claim 7, wherein the second calculation unit calculates the steering torque control value using an average value of the front yaw rate and the rear yaw rate, and provides the calculated steering torque control value to the steering driving unit.

### Claim 11 (depends on 7)

The LKAS of claim 7, wherein the second calculation unit calculates the steering torque control value using a greater value between the front yaw rate and the rear yaw rate, and provides the calculated steering torque control value to the steering driving unit.

### Claim 12

A lane keeping assist method, comprising:
capturing a front of a vehicle, and obtaining a front image of the vehicle;
calculating left and right position errors of a front portion of the vehicle, a curvature of a lane of the front portion of the vehicle, and a head angle formed based on the lane from the obtained front image of the vehicle, and calculating a steering torque control value of the front portion of the vehicle using the left and right position errors of the front portion of the vehicle, the curvature of the lane of the front portion of the vehicle, the head angle formed based on the lane, which are calculated, and a vehicle speed;
calculating left and right position errors of a rear portion of the vehicle, and a curvature of a lane of the rear portion of the vehicle, and calculating a steering torque control value of the rear portion of the vehicle using the left and right position errors of the rear portion of the vehicle, the curvature of the lane of the rear portion of the vehicle, the head angle formed based on the lane, which are calculated, and the vehicle speed; and
determining a final steering torque control value of the vehicle using the steering torque control value of the front portion of the vehicle and the steering torque control value of the rear portion of the vehicle which are calculated, and controlling steering of the vehicle for lane keeping using the final steering torque control value.

### Claim 13 (depends on 12)

The lane keeping assist method of claim 12, wherein the controlling of the steering of the vehicle determines a greater value between the steering torque control value of the front portion of the vehicle and the steering torque control value of the rear portion of the vehicle which are calculated as the final steering torque control value.

### Claim 14 (depends on 12)

The lane keeping assist method of claim 12, wherein the controlling of the steering of the vehicle calculates an average value of the steering torque control value of the front portion of the vehicle and the steering torque control value of the rear portion of the vehicle which are calculated, and determines the calculated average value as the final steering torque control value of the vehicle.