JP3589742B2 - Automotive radar equipment - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an on-vehicle radar device for monitoring the front and periphery of a vehicle, and more particularly to an on-vehicle radar device capable of correcting a beam irradiation direction depending on a curve of a traveling lane.
[0002]
[Prior art]
2. Description of the Related Art An on-vehicle radar device is provided as an alarm unit that is installed in front of a vehicle to measure a distance to an obstacle (a preceding vehicle or the like), a relative speed, and the like, and to prevent a collision (collision).
FIG. 4 is a diagram showing a system configuration of a conventional on-vehicle radar device. FIG. 5 is a diagram showing a beam irradiation state of a conventional vehicle-mounted radar device. This will be described below with reference to the drawings.
[0003]
Reference numeral 4 denotes a radar device installed in front of the vehicle 3, which emits a radar beam toward the front of the vehicle 3 and steers the sensor unit 41 in accordance with an instruction from a radar unit 43 and a sensor unit 41 for detecting a reflected wave. The steering unit 42 that corrects the beam irradiation direction receives reflected waves detected by the sensor unit 41, calculates a distance D to an obstacle (hereinafter, referred to as an inter-vehicle distance D), a relative speed, and the like. A radar ECU 43 instructs a beam irradiation direction to the controller 42.
[0004]
The radar ECU 43 receives the reflected wave detected by the sensor unit 41, calculates an inter-vehicle distance D, a relative speed, and the like from the time difference and the frequency difference, and instructs the throttle valve to adjust the vehicle 3 to an appropriate speed. When the distance D between the vehicle and the preceding vehicle is too close, the warning buzzer and the display are instructed to issue a warning. Further, a curvature radius R (hereinafter, referred to as a curve radius R) of the traveling lane of the own vehicle is calculated from data such as a vehicle speed, a steering angle, and a yaw rate (angular velocity sensor) so that the beam irradiation direction to the steering unit 42 is appropriate. The angle θ to be corrected is instructed to be.
[0005]
Next, a method of controlling the beam irradiation direction will be described. A beam is emitted from the radar device 4 installed in front of the vehicle toward the front of the vehicle 3 and a beam reflected by an obstacle (such as a preceding vehicle) is received. Measure D and relative speed. On the other hand, a curve radius R is calculated from signals from a steering angle detector, a yaw rate sensor (angular velocity sensor), and the like. Then, the irradiation angle of the beam is corrected by θ from the vehicle center line according to the equation (1).
[0006]
θ = SIN ⁻¹ (D / 2R) (1) where θ: beam irradiation direction correction angle, D: inter-vehicle distance, and R: curve radius.
In this manner, even on a curved road, the beam irradiation direction is corrected by always aiming at the position of the preceding vehicle on the driving lane (point B in FIG. 5 corresponding to the inter-vehicle distance D). Can be caught.
[0007]
[Problems to be solved by the invention]
In the conventional method of correcting the beam irradiation direction, the beam is corrected by always aiming at the position of the preceding vehicle on the traveling lane even on a curved road, so that the preceding vehicle can be reliably captured, but the inter-vehicle distance D is large. When the curve radius R is reduced, as shown in FIG. 5, there is a portion (hatched area) where the vicinity of the vehicle 3 deviates from the beam even though the vehicle is in the traveling lane. For this reason, there arises a problem that detection of a small vehicle traveling near the own vehicle is delayed or detection of a vehicle interrupting from an adjacent lane is delayed. In addition, even if the beam is aimed at a distant front vehicle, there is a problem that a traveling vehicle or a guardrail in an adjacent lane (inner lane) is actually detected and a warning is issued.
[0008]
According to the present invention, according to the condition of the curve of the road, the beam can be aimed at an appropriate position, the vehicle on the curved road can be detected, and the nearby vehicle can be detected, so that the vehicle on the adjacent driving lane is not erroneously detected. It is an object of the present invention to provide a radar apparatus for a vehicle.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an in-vehicle radar device that corrects a beam irradiation direction at a predetermined correction angle according to a curve situation of a traveling lane, wherein a limiting unit that limits the correction angle at an upper limit is provided. It is characterized by having.
The limiting means includes a comparing means for comparing a distance DR set in advance corresponding to a radius of curvature R of a running lane of the vehicle with an inter-vehicle distance D between the vehicle and a vehicle traveling ahead of the vehicle. Extracting the correction angle from the inter-vehicle distance D and the radius of curvature R. When the inter-vehicle distance D is determined to be larger than the distance DR by the comparing means, the inter-vehicle distance D is calculated as the distance And DR extraction means.
[0010]
[Action]
In the present invention, for example, beam irradiation is performed based on the inter-vehicle distance D to the preceding vehicle measured by a radar device installed in front of the vehicle and the curve radius R of the running lane of the own vehicle measured by a yaw rate sensor, a vehicle speed sensor, and the like. Correct the direction. The distance DR 1 set in advance corresponding to the curve radius R is set such that the smaller the curve radius R, the smaller the distance DR 2. The comparing means compares a distance DR 1 set in advance corresponding to the inter-vehicle distance D and the curve radius R. If the inter-vehicle distance D is smaller, the beam irradiation area (detection area) does not greatly deviate from the traveling lane of the own vehicle even if the preceding vehicle is tracked directly. Aim at the position. However, if the inter-vehicle distance D is larger, if the vehicle directly tracks the preceding vehicle, the beam irradiation area is greatly deviated from the traveling lane of the own vehicle. As a result, it becomes impossible to detect obstacles in the own vehicle's driving lane near the own vehicle and also to detect obstacles in the lane inside the own vehicle, so as not to aim the beam too far. There is an upper limit on the distance to aim. That is, the distance is replaced with an appropriate distance DR corresponding to the curve. Thus, an undetectable area on the own vehicle lane can be reduced.
[0011]
【Example】
FIG. 1 is a diagram showing a system configuration of an on-vehicle radar device according to one embodiment of the present invention. FIG. 2 is a diagram showing a beam irradiation state. 3A and 3B are diagrams showing a method of controlling the direction of a radar beam. FIG. 3A is a flowchart showing the operation of the CPU, and FIG. 3B is a DR map corresponding to a curve radius R. This will be described below with reference to the drawings.
[0012]
Reference numeral 1 denotes a radar device installed in front of the vehicle 3 for irradiating a radar beam toward the front of the vehicle 3 and correcting the beam irradiation direction according to an instruction from the sensor unit 11 and the radar ECU 13 for detecting the reflected wave. The steering unit 12 includes a radar ECU 13 that receives reflected waves detected by the sensor unit 11, calculates an inter-vehicle distance D, a relative speed, and the like, and instructs the steering unit 12 on a beam irradiation direction.
[0013]
The radar ECU 13 is provided with a curvature radius R measuring means for measuring a curvature radius R (curve radius R) of the traveling lane based on data such as a steering angle and a yaw rate (angular velocity sensor). ), A ROM (Read Only Memory), a RAM (Random Access Memory) and the like.
The sensor unit 11 irradiates an area as shown in FIG. 2 toward the front of the vehicle 3, and a reflected wave from an object in the area can be received (detectable) by the sensor unit 11. Send to radar ECU13.
[0014]
The radar ECU 13 receives the reflected wave detected by the sensor unit 11 and calculates the inter-vehicle distance D and the relative speed based on the time difference and the frequency shift, and the throttle valve so that the vehicle 3 has an appropriate speed. Instruction means for instructing adjustment, or when the inter-vehicle distance D from the preceding vehicle is too close, an alarm buzzer, an instruction means for instructing a display to issue an alarm, a vehicle speed, a steering angle, and a yaw rate. (Angular velocity sensor) and the like, the curve radius R of the own vehicle traveling lane is calculated, and the beam irradiation direction to the steering unit 12 is corrected based on the curve radius R and the inter-vehicle distance D so as to be appropriate. Correction means and the like for indicating the power angle θa are provided, and these means comprise the same CPU, ROM, RAM and the like as described above.
[0015]
Reference numeral 14 denotes a memory in which the relationship of the distance DR to be aimed at corresponding to the curve radius R is stored as a map, and corresponds to, for example, the ROM described above.
Next, a radar beam direction control method will be described with reference to the flowchart of FIG. 3A showing the operation of the CPU and the DR map of FIG.
In step S1, a curve radius R is calculated, and the process proceeds to step S2. That is, in order to grasp the direction in which the own vehicle travel lane extends, the curvature radius (hereinafter, referred to as a curve radius) R of the travel lane is calculated according to equation (2) based on data from the vehicle speed sensor and the yaw rate (angular velocity sensor). I do.
[0016]
R = 180V / Yπ (2) where R: radius of curvature (curve radius), V: vehicle speed, and Y: angular speed.
In step S2, a distance DR corresponding to the curve radius R is calculated. This distance DR is an upper limit parameter for the inter-vehicle distance D. That is, the distance DR 1 corresponding to the curve radius R stored in the memory 14 in advance is read. As shown in FIG. 3B, this distance DR is a map of the curve radius R and the distance DR. For example, if the curve radius is calculated to be 500 m in step S1, the distance DR is 50m. Note that the distance DR is determined only by the curve radius R. If the vehicle is aimed at a distance farther than the distance DR, an obstacle in an adjacent lane is detected, or the “detection is delayed” in a short distance of the own vehicle traveling lane. May occur. In step S3, the inter-vehicle distance D is calculated, and the process proceeds to step S4. That is, the inter-vehicle distance D is calculated from the difference in the reflection time of the beam emitted from the sensor unit 11 toward the preceding vehicle.
[0017]
In step S4, it is determined whether or not D ≦ DR 2 by comparing the inter-vehicle distance D with the distance DR 2 set by the curve radius R. If D ≦ DR, the process proceeds to step S5. If D ≦ DR, the process proceeds to step S7. In other words, if the vehicle in front is too far from the curving lane where the car is curving, and the radar is aimed at that position, it will detect vehicles and guardrails in the inner lane and detect areas near the car lane. This is to determine whether or not it is no longer possible.
[0018]
In step S5, the inter-vehicle distance D is used as the distance Da for aiming the beam of the sensor unit 11. That is, when the inter-vehicle distance D is short, the vehicle follows the preceding vehicle as before. In step S7, the distance DR is used as the distance Da for aiming the beam of the sensor unit 11. In other words, if the following distance D is long, and if the preceding vehicle is tracked as before, there is a possibility that a "region where detection is delayed" may occur in the short distance of the own vehicle traveling lane. Aim at a shorter distance DR 2 (point A in FIG. 2). In step S6, the beam correction angle θa of the sensor unit 11 is calculated by equation (3), and the process proceeds to step S8.
[0019]
θa = SIN ⁻¹ (Da / 2R) (3) where θa is a correction angle of beam irradiation direction, Da is a distance to be aimed, whichever is smaller of D and DR, R: radius of curvature (curve radius) of the traveling lane. In step S8, the radar ECU 13 instructs the steering unit 12 to correct the beam irradiation angle of the sensor unit 11 by θa with respect to the vehicle center line, and ends the processing.
[0020]
As described above, in the present embodiment, instead of simply aiming the beam based on the inter-vehicle distance R so as to track the preceding vehicle, the distance to be aimed at the beam is changed according to the state of the curve. It is not possible to detect an obstacle in the inner lane or to detect an obstacle in the area near the own vehicle lane, and it is possible to perform detailed monitoring for an unexpected situation such as an interruption.
[0021]
Further, in this example, since the correction angle is limited by software inside the radar ECU, there is no increase in cost due to the limitation. In addition to the present example, a lower limit parameter may be set for the curve radius R to limit that R is too small, and an upper limit value is set for the correction angle itself to limit the correction angle mechanically or softly. May be. Note that the angle extraction in this example is performed by calculation, but is not limited to this, and may be performed by selecting data such as a map.
[0022]
【The invention's effect】
As described above, in the present invention, the irradiation direction of the beam is controlled so that the beam of the sensor unit can detect an obstacle in a wide area of the own vehicle traveling lane, and the beam is always appropriately adjusted according to the situation of the curve. Can be detected, which is effective for safe driving.
[Brief description of the drawings]
FIG. 1 is a diagram showing a system configuration of an on-vehicle radar device according to an embodiment of the present invention.
FIG. 2 is a diagram showing a beam irradiation state of the on-vehicle radar device according to one embodiment of the present invention.
3A and 3B are diagrams illustrating a beam direction control method of a vehicle-mounted radar device according to an embodiment of the present invention, wherein FIG. 3A is a flowchart illustrating an operation of a CPU, and FIG. 3B is a DR map corresponding to a curve radius; .
FIG. 4 is a diagram showing a system configuration of a conventional on-vehicle radar device.
FIG. 5 is a diagram showing a beam irradiation state of a conventional vehicle-mounted radar device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Radar apparatus 11 ... Sensor part 12 ... Steering part 13 ... Radar ECU
14 ... Memory

Claims (1)

In the vehicle-mounted radar device that corrects the irradiation direction of the beam at a predetermined correction angle according to the curve situation of the traveling lane,
Providing limiting means for limiting the correction angle at the upper limit,
The limiting means includes:
Comparing means for comparing a predetermined distance DR corresponding to a radius of curvature R of a travel lane of the vehicle with an inter-vehicle distance D between the vehicle and a vehicle traveling ahead of the vehicle;
The correction angle is extracted from the inter-vehicle distance D and the radius of curvature R. When the inter-vehicle distance D is determined to be larger than the distance DR by the comparing means, the inter-vehicle distance D is calculated as the distance DR. An on-vehicle radar device, comprising: an extracting unit.

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