JP3209671B2 - Curved road judgment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for determining a curved road used in a radar tracking device for tracking a preceding vehicle, and more particularly to a curved road determining device capable of clearly distinguishing between traveling on a curved road and changing lanes. About.

[0002]

2. Description of the Related Art A millimeter wave for irradiating a millimeter wave radio wave toward the front of a vehicle to prevent a rear-end collision and calculating the traveling speed of the preceding vehicle and the distance to the preceding vehicle (inter-vehicle distance) from the reflected wave. There is a radar device. At this time, when the road (hereinafter, referred to as a driving lane) is not a straight line but a curve, a radio wave (beam) corresponding to the radius of curvature of the curved road of the driving lane.
If the irradiation direction of the vehicle is not adjusted, the preceding vehicle cannot be accurately captured. Therefore, a yaw rate sensor that detects an angular velocity ω generated when the vehicle travels on a curved road is installed, and the output ω of the yaw rate sensor during traveling on a curved road is provided.
The radius of curvature R of the road is calculated based on the vehicle speed V, and the beam irradiation direction is controlled.

[0003] However, in the case of a running vehicle, the steering wheel operation is constantly performed not only to change the curve of the driving lane but also to change lanes and avoid obstacles on the road. When traveling on a curved road, it is necessary to change the beam irradiation direction to track the preceding vehicle, but when temporarily changing lanes or avoiding obstacles on the road, adjust the beam irradiation direction each time No need. Therefore, it is important to determine whether the output ω of the yaw rate sensor is due to the curve of the traveling lane.

Conventionally, since the output ω of the yaw rate sensor constantly fluctuates, a threshold value is set for the output ω of the yaw rate sensor. It was determined that the driving lane was curved.

[0005]

In the above-mentioned method, when the vehicle changes lanes slowly, it cannot be distinguished from a curved road, so that the threshold value (judgment level) must be set higher. . For this reason, even though the traveling lane is curved, a curve may not be detected or detection may be delayed depending on the magnitude of the threshold value. In particular, during low-speed running, the effect becomes a significant problem.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a curved road determining apparatus which can reliably determine whether a vehicle is traveling on a curved road or a lane change based on an output of a yaw rate sensor.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a yaw rate sensor for detecting an angular velocity ω of a running vehicle, and the vehicle based on the angular velocity ω output from the yaw rate sensor. A vehicle speed sensor for detecting a traveling speed V of the vehicle, an integral value calculating means for calculating an integral value θ of the angular velocity ω, and an output V of the vehicle speed sensor. A moving amount calculating means for calculating a moving amount X in a direction perpendicular to the traveling direction of the vehicle based on the integral value θ; a moving amount X calculated by the moving amount calculating means; Comparing means for comparing a value W corresponding to the width of the road;
When the comparing means detects that the movement amount X is larger than W corresponding to the width of the road on which the vehicle travels, the comparison means includes a curve road determination means for determining that the vehicle is traveling on a curved road. It is a feature.

When it is detected that the angular velocity ω is at a predetermined time 0 or the integral value θ is at a constant value for a predetermined time, the integral value calculating means is reset to the integral value, and the integral value θ is reset again. The reset means for starting the calculation of is provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining the operation principle of a curved road judging device according to one embodiment of the present invention. Hereinafter, the operation principle of the curved road determination device will be described with reference to the drawings. Considering the state in which the vehicle 9 at the point A travels on the curved road at a constant angular velocity ω and moves to the point B, the radius of the curved road R (m),
The relationship between the angle change θ during that time and the amount of movement X in the direction perpendicular to the traveling direction of the vehicle 9 is as shown in equation (1).

X = 2R sin ² (θ / 2) (1) Since the moving distance of the vehicle 9 on the arc is the speed of the vehicle × time, R = Vt / θ. (2) R: curve radius (m) θ: angle change (radian) V: vehicle speed (m / sec) X: travel distance in the direction perpendicular to the traveling direction of the vehicle (m) Equation (1) From the equation (2), X = (2Vt / θ) × sin ² (θ / 2) (3) If the moving amount X in the direction perpendicular to the traveling direction of the vehicle is larger than the road width W, Instead of changing the traveling lane, it can be determined that the vehicle is traveling on a curved road.

That is, when traveling on a curved road, X> W (4) Expression (4) > W + α (5) It is determined that the vehicle is traveling on a curved road when the condition of the expression (4) or the expression (5) is satisfied. The road width W may be a value determined based on an expressway or the like stored in advance in a ROM or the like, or may be set in real time based on navigation map data or external communication data.

FIG. 2 is a diagram showing a system configuration of a curved road judging device according to one embodiment of the present invention. Hereinafter, description will be made with reference to the drawings. Reference numeral 1 denotes a yaw rate sensor for measuring an angular velocity ω of a running vehicle, and detects a distortion of an element caused by the angular velocity. A speed sensor 2 is connected to an axle or the like and measures a vehicle speed V. A millimeter wave radar signal processing ECU 3 calculates a beam irradiation direction based on signals from the yaw rate sensor 1, the vehicle speed sensor 2, and the millimeter wave radar sensor 51, outputs the calculated beam irradiation direction to the beam steering ECU 53, and outputs the beam steering angle to the beam steering 52. Control. In addition, based on the beat signal obtained by the millimeter-wave radar, data of the relative distance to the preceding vehicle and the relative speed are calculated, and these data are output to the cruise ECU 6. Reference numeral 6 denotes a cruise ECU for controlling the vehicle speed by adjusting the throttle actuator 7 based on the output of the millimeter wave radar signal processing ECU 3 so as to maintain the relative position with respect to the preceding vehicle.
It is.

Reference numeral 31 denotes a yaw rate value integrating means for integrating the output ω from the yaw rate sensor 1. Numeral 32 denotes a moving amount X calculating means for calculating a moving amount X in the direction of the radius of gyration (that is, the component perpendicular to the traveling direction of the vehicle) when the vehicle travels on a curved road. A memory 33 stores a reference value (lane width W + margin value α) as a reference for determining whether the vehicle is traveling on a curved road or changing lanes. Reference numeral 34 denotes a comparator that compares the vertical movement amount X of the vehicle with a reference value (W + α) to determine whether the vehicle is traveling on a curved road. Incidentally, the yaw rate value integration means 31, the movement amount X calculation means 32, the memory 33, the comparator 34
And the reset means 35 are the millimeter wave radar signal processing ECU 3
And a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). Therefore, the processing of the millimeter wave radar signal processing ECU 3 is performed by software.

Next, the operation will be described. During traveling of the vehicle, the angular velocity ω corresponding to the curved road is constantly output from the yaw rate sensor 1, and the output ω is input to the yaw rate value integrating means 31 to calculate the angle change θ of the vehicle.
On the other hand, based on the output V from the vehicle speed sensor 2, the moving amount X calculating means 32 calculates the moving amount X in the direction perpendicular to the traveling direction of the vehicle by the formula (3) and outputs the calculated amount to the comparator 34. Comparator 3
Reference numeral 4 indicates that when the movement amount X is larger than the movement amount X and the reference value (W + α) stored in the memory 33 in advance, the vehicle is determined to be traveling on a curved road, and a curve road detection signal is output. Output. In addition, assuming a case where two lanes are changed at a time on a wide road having three or more lanes on one side, such a road may be dealt with by a method such as setting a large margin value α.

The curve detection signal is a beam steer EC.
It is sent to U53. When it is determined that the road is a curved road, the beam steering ECU 53 calculates the radius of curvature R of the curved road based on the equation (2), calculates the corresponding beam irradiation angle, and causes the beam steering 52 to change the beam irradiation angle. 3A and 3B are diagrams for explaining a calculation period of the movement amount X of the curved road determination device of one embodiment of the present invention in FIG. 3, where FIG. 3A illustrates a position of a vehicle in a lane, and FIG. Diagram showing the relationship between yaw rate values,
(C) is a diagram showing a relationship between time and an integrated yaw rate value. Hereinafter, description will be made with reference to the drawings.

As shown in FIG. 3 (a), when a vehicle traveling in the traveling lane to the left of point A changes lanes to the traveling lane to the right and reaches point B, the output from yaw rate sensor 1 is shown in FIG. As shown in FIG. 3 (b), at time ta from time ta, it first changes to the + side (left side), and thereafter, the yaw rate value becomes 0.
After passing through the point (time tb), the yaw rate value changes to the minus side (right side). Then, at time tc when the lane change is completed and the vehicle moves to the right traveling lane, the yaw rate value becomes 0 again.

When this is seen from the integrated value of the time and the yaw rate value, as shown in FIG. 3 (c), it rises with time t from time ta, becomes maximum at time tb, and becomes 0 again at time tc when the lane change is completed. . That is, in the lane change, the direction of the vehicle does not change before and after the lane change. It should be noted that the integrated value of the yaw rate value before and after the vehicle is not limited to the lane change and becomes zero even before and after traveling around the obstacle. After all, the movement amount X does not become larger than the road width W from the time ta to tb, and the calculation is started again from 0 without being recognized as traveling on a curved road.

That is, when calculating the moving amount X in the direction perpendicular to the traveling direction of the vehicle, the starting condition is a time when it is determined that the vehicle is in the straight traveling state (the yaw rate value ω is 0).
Is the predetermined time t1) or when the integrated value of the yaw rate value becomes 0, ta, tc (tc
Is also the next start condition at the same time as the end condition). In addition, the end condition is set to a time point tc at which the integrated value of the yaw rate value becomes 0 again. If the integrated value of the yaw rate value becomes 0 during repeated small steering operations such as changing lanes, the movement amount X at that time is reduced. Since it is cleared each time, the movement amount X is not larger than the road width W (or W + α), and it is not determined that the road is a curved road. On the other hand, since the integrated value of the yaw rate value does not become 0 forever while traveling on a curved road, the integration period becomes longer, and as a result, the movement amount X becomes larger, and it is determined that the vehicle is traveling on a curved road.

When the vehicle turns at a curved road or an intersection, the calculation of the movement amount X is started from the point B in FIG. 3 (a), and when the movement amount X exceeds the road width W (or W + α). At (point C), even if the integrated value of the yaw rate ω value does not return to 0 again, it is determined that the vehicle is on a curved road. However, when the vehicle goes straight after turning on a curved road or an intersection, etc., since the direction of the vehicle has changed even if the yaw rate value ω becomes 0, the integrated value of the yaw rate value ω returns to 0. Therefore, the calculation of the next movement amount X cannot be started. Therefore, the reset means 35 determines that the curved road has ended at the time te when the time during which the yaw rate value ω is 0 has continued for the predetermined time t2 (or when the integration value θ has continued at t2 with a constant value other than 0) te. And the integral value θ of the yaw rate value ω and the integral time t
Reset. Then, the calculation of the next movement amount X is started from the time point te. Note that the integration value θ and the integration time t may be reset at the time point tb. According to this, every time the vehicle exits a small turn, a curve road determination is made,
(3) Accurate processing according to the equation can be performed (since this equation is based on one circular motion).

As described above, in this embodiment, the travel amount in the direction perpendicular to the traveling direction of the vehicle is compared with the lane width, and it is determined that the vehicle is traveling on a curved road when the travel amount exceeds the road width. In addition, the determination time of a curved road is early, and it is possible to appropriately determine whether the vehicle is traveling on a curved road or changing lanes.

[0021]

As described above, according to the present invention, it is possible to provide a curved road determining apparatus which can accurately determine whether the vehicle is traveling on a curved road or a lane change based on the output of the yaw rate sensor. As a result, control corresponding to a lane change or a curved road can be accurately performed.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the operation principle of a curved road determination device according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating a system configuration of a curved road determination device according to an embodiment of the present invention.

3A and 3B are diagrams for explaining a calculation period of a movement amount X of the curved road determination device according to one embodiment of the present invention, where FIG. 3A illustrates a position of a vehicle in a lane, and FIG. FIG. 3C is a diagram illustrating a relationship between instantaneous yaw rate values, and FIG. 3C is a diagram illustrating a relationship between time and an integrated yaw rate value.

[Explanation of symbols]

1 ... Yaw rate sensor 34 ... Comparator 2 ... Vehicle speed sensor 51 ... Millimeter wave radar sensor 3 ... Millimeter wave radar signal processing ECU 52 ... Beam steering 31 ... Yaw rate Value integration means 53 ... Beam steer ECU 32 ... Movement amount calculation means 6 ... Cruise ECU 33 ... Memory

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G08G 1/00-9/02 G01S ⁷ /00-7/42 G01S 13/00-13/95

Claims (2)

(57) [Claims] 1. A curved road determining device, comprising: a yaw rate sensor for detecting an angular velocity ω of a running vehicle; and determining a traveling state of the vehicle on a curved road based on the angular velocity ω output from the yaw rate sensor. A vehicle speed sensor for detecting a traveling speed V of the vehicle; an integral value calculating means for calculating an integral value θ of the angular velocity ω; an output V of the vehicle speed sensor and the integral value θ, based on the traveling direction of the vehicle. Moving amount calculating means for calculating a moving amount X in the vertical direction, and comparing means for comparing the moving amount X calculated by the moving amount calculating means with a value W corresponding to a width of a road on which the vehicle travels. And a curve road determining means for determining that the vehicle is traveling on a curved road when the comparing means detects that the movement amount X is larger than W corresponding to the width of the travel road of the vehicle. To Characteristic curve road determination device. 2. The angular velocity ω is at 0 for a predetermined time,
Alternatively, reset means is provided for resetting the integral value to the integral value calculating means when the integral value θ is detected to be a constant value for a predetermined time and restarting the calculation of the integral value θ. Item 2. The curved road determination device according to Item 1.