Automotive radar system

• US 20030201878A1
• Filed: 04/22/2003
• Published: 10/30/2003
• Est. Priority Date: 04/24/2002
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.), Seiko Epson Corporation (Seiko Group)
• Original Assignee: HITACHI, LTD. AND HITACHI CAR ENGINEERING, CO., LTD.
• Inventors: Bai, Jie, Kuroda, Hiroshi
• Granted Patent: US 6,825,756 B2
• Time in Patent Office: Days
• US Class Current: 340/435
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9318 Controlling the steering
• CPC Class Codes: G01S 2013/93185 Controlling the brakes
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/9325 for inter-vehicle distance regulation, e.g. navigating in platoons
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles

Abstract

The invention provides a radar system, which can increase a crossrange detection speed in the lane change state by employing a steering angle sensor, etc. loaded on a vehicle without providing additional hardware. A lane-change determining unit receives a yaw rate response from a steering angle sensor, etc., and determines whether the radar-loaded vehicle is in the steering operation for lane change. If the radar-loaded vehicle is in the lane change state, a gain setting unit shifts a tracker gain to a larger value than that in ordinary running, and calculates a range, a crossrange, a relative velocity, etc. relative to a target from the results of tracker processing executed by a filtering unit. By using the calculated range, crossrange, relative velocity, etc., a control determining unit determines whether there is a collision risk, and whether steering operation to avoid a collision is required. If there is a collision risk, a forward collision warning and a control signal for actuating automatic braking are issued. If automatic steering to avoid a collision is required, an automatic steering control signal is issued. When the lane change state is completed, the radar system is returned to the state employing a tracker gain for the ordinary running.

Claims

1. An automotive radar system for detecting at least one of a range, a crossrange, an azimuth and a relative velocity relative to a target, the system comprising:

lane-change behavior state detecting section for detecting whether a radar-loaded vehicle is in a lane-change behavior state; and

detection response speed changing section for changing a target detection response speed of the radar system to a value larger than that in a running state other than the lane-change behavior state when said lane-change behavior state detecting section detects that the radar-loaded vehicle is in the lane-change behavior state.

2. An automotive radar system according to claim 1, wherein said detection response speed changing section comprises filtering section for executing a filtering process with a smoothing effect on at least one of the range, the crossrange, the azimuth and the relative velocity relative to said target, and filter gain changing section for increasing a gain of said filtering section, wherein the target detection response speed is set to a value larger than that set in the running state other than the lane-change behavior state by increasing the gain of said filtering section.

3. An automotive radar system according to claim 1, wherein said lane-change behavior state detecting section includes at least one of a yaw rate or lateral acceleration sensor, a steering angle sensor, a steering torque sensor, a yaw rate sensor, a tire pressure sensor, and a lateral acceleration sensor, and detects the lane-change behavior state of the radar-loaded vehicle in accordance with an output of the at least one sensor.

4. An automotive radar system according to claim 1, wherein said lane-change behavior state detecting section includes radar-loaded-vehicle lane determining section for calculating a status variable given as a second time-derivative status variable representing a change amount of a steering angular speed or a change amount of a yaw rate, and then determining that the radar-loaded vehicle is in the lane-change behavior state, when the calculated status variable exceeds a predetermined level.

5. An automotive radar system according to claim 1, further comprising radar detected value modifying section for modifying at least one of the range, the crossrange, the azimuth and the relative velocity relative to said target by using a longitudinal or transverse momentum and/or a speed of the radar-loaded vehicle when said lane-change behavior state detecting section detects that the radar-loaded vehicle is in the lane-change behavior state.

6. An automotive radar system according to claim 1, further comprising radar-loaded-vehicle transverse movement detecting section for detecting a longitudinal momentum, a transverse momentum and/or a speed of the radar-loaded vehicle by using an output of a vehicle speed sensor, an acceleration sensor and/or a steering angle sensor.

7. An automotive radar system according to claim 1, wherein a forward collision warning is issued when the crossrange from a center of the radar-loaded vehicle to said target is detected as being less than a predetermined value, and the forward collision warning is automatically stopped when the crossrange from the center of the radar-loaded vehicle to said target is detected as being not less than the predetermined value.

8. An automotive radar system according to claim 1, wherein deceleration control with braking is performed when the crossrange from a center of the radar-loaded vehicle to said target is detected as being less than a predetermined value, and the deceleration control with braking is automatically stopped when the crossrange from the center of the radar-loaded vehicle to said target is detected as being not less than the predetermined value.

9. An automotive radar system for detecting at least one of a range, a crossrange, an azimuth and a relative velocity relative to a target, the system comprising:

lane-change behavior state detecting section for detecting whether a radar-loaded vehicle is in a lane-change behavior state; and

radar detected value modifying section for modifying at least one of the range, the crossrange, the azimuth and the relative velocity relative to said target by using a longitudinal and/or transverse momentum or a speed of the radar-loaded vehicle when said lane-change behavior state detecting section detects that the radar-loaded vehicle is in the lane-change behavior state.

10. An automotive radar system for detecting at least one of a range, a crossrange, an azimuth and a relative velocity relative to a target, the system comprising:

lane-change behavior state detecting section for detecting whether a radar-loaded vehicle is in a lane-change behavior state; and

warning stopping section for issuing a forward collision warning when the crossrange from a center of the radar-loaded vehicle to said target is detected as being less than a predetermined value, and automatically stopping the forward collision warning when the crossrange from the center of the radar-loaded vehicle to said target is detected as being not less than the predetermined value.

11. An automotive radar system for detecting at least one of a range, a crossrange, an azimuth. and a relative velocity relative to a target, the system comprising:

lane-change behavior state detecting section for detecting whether a radar-loaded vehicle is in a lane-change behavior state; and

brake deceleration canceling section for performing deceleration control with braking when the crossrange from a center of the radar-loaded vehicle to said target is detected as being less than a predetermined value, and automatically stopping the deceleration control with braking when the crossrange from the center of the radar-loaded vehicle to said target is detected as being not less than the predetermined value.