JP2008280016A - Vehicle control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle control device performing a control accommodated to a sense of danger of a driver when a vehicle enters in a curve. <P>SOLUTION: A brake discriminating expression in a section when entering in a curve is set. An increase gradient of the discriminating expression in a section when entering in a curve is sharper than an increase gradient of a preset brake discriminating expression. Until one's own vehicle reaches the section when entering in a curve, it is determined whether or not a present value KdB_c_p of a correction approach/separation state evaluation index exceeds the preset brake discriminating expression. In the section when entering a curve, it is determined whether or not a present value KdB_c_p of the correction approach/separation state evaluation index exceeds the brake discriminating expression in the section when entering a curve. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle control device.

Conventionally, a vehicle control device that performs vehicle speed control when passing a curve has been proposed (see, for example, Patent Document 1). According to the vehicle control device described in Patent Document 1, when the host vehicle decelerates from the vehicle speed V0 at a predetermined deceleration, a distance (prefetch distance) that can be stopped within a predetermined time t2 is obtained, and the vehicle control position is determined based on the vehicle position. A second reference node is set at the temporary vehicle position set forward by the pre-reading distance, and a third reference node is set at the front position by a distance a (a = vehicle speed V0 × predetermined time t1) from the second reference node. . In addition, a passable vehicle speed for passing between the second reference node and the third reference node at a reference lateral acceleration or less is obtained. Then, if the presence of a curve is determined on the road ahead and the vehicle speed V0 exceeds the passable vehicle speed, automatic deceleration by the vehicle speed control means is performed so that the vehicle can surely pass the curve.
Japanese Patent No. 3342881

  The above-described vehicle control device disclosed in Patent Document 1 merely determines a vehicle speed that can be passed to pass below the reference lateral acceleration, and cannot perform vehicle speed control that takes into account the driver's sense of danger. Therefore, the applicant of the present application sets a target speed Vs0_t for traveling on the curve based on the current value Gy_p of the lateral G of the vehicle when the vehicle is traveling on the curve and the curvature radius R of the curve, and this When the speed difference between the set target speed Vs0_t and the speed Vs0 of the host vehicle is larger than the predetermined speed difference, the current approach / separation state evaluation index KdB_p of the host vehicle, the road accessory located on the extension line of the host vehicle traveling direction The target acceleration / deceleration dVs0dt for accelerating / decelerating the vehicle from the distance D between the vehicle and the vehicle, the vehicle speed Vs0, and the target speed Vs0_t to the target speed Vs0_t is obtained. An application was filed for a vehicle control device that executes acceleration / deceleration control so that the speed dVs0dt is obtained (Japanese Patent Application No. 2006-239420).

  However, in this vehicle control device, the curvature radius R of the curve increases as the distance D between the road accessory and the host vehicle increases at a point before the entrance of the curve. The target speed Vs0_t for traveling is calculated to be large, and the curvature radius R of the calculated curve becomes small at the entrance point of the curve, so the target speed Vs0_t for traveling on the curve ahead of the host vehicle is calculated to be small. For this reason, the speed difference between the vehicle speed Vs0 and the target speed Vs0_t is not sufficiently reduced by the entrance of the curve, and as a result, it is not possible to execute control that matches the driver's danger when entering the curve. was there.

  In view of the above problems, an object of the present invention is to provide a vehicle control device capable of executing control that matches the driver's danger when entering a curve.

The vehicle control device according to claim 1, which has been made to achieve the above object,
A distance acquisition means for acquiring a distance between the vehicle and a road accessory provided on or near a road boundary of a curved road located on an extension line in the traveling direction of the vehicle;
Speed acquisition means for acquiring the speed of the vehicle;
A relative speed detecting means for detecting a relative speed between a road boundary or a road accessory and the vehicle;
As the index indicating the approaching / separating state of the vehicle with respect to the road boundary or road accessory taking into account the speed of the road boundary or road accessory and the vehicle, it increases as the relative speed approaching the road boundary or road accessory increases. An evaluation index calculating means for calculating a corrected approaching / separating state evaluation index in which the increasing gradient becomes steeper as the distance from the road boundary or road accessory decreases at each relative speed;
A radius of curvature acquisition means for acquiring a radius of curvature of a curved road;
A target travel relative speed setting means for setting a target travel relative speed when the vehicle travels on the curve road from a curvature radius of the curve road and a target lateral acceleration targeted when the vehicle travels on the curve road;
Based on the target travel relative speed, the target approach relative speed that should be the target of the vehicle at a point before the entrance point of the curve road is set, and the target approach is a relative speed that exceeds the target travel relative speed. Target approach relative speed setting means for setting a relative speed;
Using the target running relative speed and the target approach relative speed, the increase gradient of the corrected approach / separation state evaluation index in the curve approach section from the point before the entrance of the curve road to the entrance point of the curve road is set in advance. A curve approach section threshold value setting means for setting a threshold value of the corrected approach / separation state evaluation index in the curve approach section, which is steeper than the increasing gradient of the threshold value of the approach / separation condition evaluation index;
Until the vehicle reaches the curve approach section, it is determined whether the corrected approach / separation state evaluation index calculated by the evaluation index calculation means exceeds a preset threshold value of the corrected approach / separation state evaluation index. Then, a threshold determination unit that determines whether the corrected approaching / separating state evaluation index calculated by the evaluation index calculating unit exceeds the threshold value of the corrected approaching / separating state evaluation index in the curve approaching section set by the curve approaching section threshold setting unit;
If the threshold determination means determines that the vehicle exceeds the threshold, the vehicle decelerates to the target travel relative speed until the vehicle reaches the curve approach zone from the target travel relative speed, the target approach relative speed, and the relative speed of the host vehicle. Target deceleration calculating means for calculating a target deceleration for calculating the target deceleration for decelerating the vehicle to the target approach relative speed in a curve approach section;
Vehicle control means for performing deceleration control so that the deceleration generated in the host vehicle becomes the target deceleration.

  As a result, when the vehicle enters the curve road, the speed of the vehicle is decelerated with the target traveling relative speed when traveling on the curve road before reaching the curve entry section as a target. In the section, the vehicle is decelerated with a target approach relative speed that is a relative speed exceeding the target travel relative speed as a target. As a result, the speed of the vehicle is sufficiently decelerated to a point before the entrance of the curve, and the degree of deceleration is reduced in the curve approach section. It is possible to execute control that suits the feeling.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this embodiment demonstrates the case where the vehicle control apparatus of this invention is applied to a driving assistance system. In FIG. 1, the whole structure of the driving assistance system of this embodiment is shown. As shown in the figure, this driving support system includes a VSC_ECU 10, a steering angle sensor 20, a G sensor 30, a yaw rate sensor 40, an ENG_ECU 50, a road-to-vehicle communication device 60, a radar 70, an operation SW 80, a navigation device 90, and a vehicle control ECU 100. Consists of.

  A VSC_ECU 10 shown in FIG. 1 controls a brake actuator (not shown) that applies a braking force to the host vehicle, and has a control function of VSC (Vehicle Stability Control (registered trademark)) that suppresses a side slip of the host vehicle. The VSC_ECU 10 receives information on the target deceleration from the in-vehicle LAN, and controls the brake actuator so that the target deceleration is generated in the host vehicle. Further, the VSC_ECU 10 transmits information on the speed (vehicle speed) Vs0 of the own vehicle and the brake pressure to the in-vehicle LAN. The steering angle sensor 20 is a sensor that detects information on the steering angle of the steering of the host vehicle, and transmits information on the detected steering angle to the in-vehicle LAN.

  The G sensor 30 is an acceleration sensor that detects acceleration (front-rear G) generated in the front-rear direction of the host vehicle and acceleration (lateral G) generated in the lateral (left-right) direction, and information on the detected front-rear G and lateral G is detected. To the in-vehicle LAN. The yaw rate sensor 40 is a sensor that detects an angular velocity (yaw rate) around the vertical axis of the host vehicle, and transmits information on the detected yaw rate to the in-vehicle LAN.

  The ENG_ECU 50 receives target acceleration information from the in-vehicle LAN and controls a throttle actuator (not shown) so that the host vehicle generates the target acceleration. The road-to-vehicle communication device 60 is a wireless communication device that performs road-to-vehicle communication with a road-side communication device (road-side infrastructure) installed on a road. When a road ahead in the traveling direction of the vehicle curves, the entrance of the curve At a point sufficiently before the point, the radius of curvature of the curve (curve R), the friction coefficient μ of the road surface, the coordinates of the entrance / exit point of the curve (latitude and longitude), the width of the curve, the number of lanes, the width of each lane, etc. Receive curve information. For this road-vehicle communication, DSRC (Dedicated Short Range Communication) is adopted.

  For example, the radar 70 irradiates a predetermined range ahead of the host vehicle with laser light, receives the reflected light, and shows a reflected light intensity of a predetermined intensity or higher provided at or near a road boundary of a curved road. The distance from the road accessory such as a delineator, the shift amount (lateral deviation) between the center axis of the vehicle width and the center axis of the road accessory, and the like are detected and output to the vehicle control ECU 100.

  The operation SW 80 is a switch group operated by the driver of the host vehicle, and operation information of the switch group is output to the vehicle control ECU 100. The navigation device 90 includes a well-known geomagnetic sensor, a gyroscope, a distance sensor, and a GPS receiver for GPS (Global Positioning System) that detects the position of the vehicle based on radio waves from a satellite. A position detection unit, a road map data storage unit for storing road map data, a color display using a liquid crystal or a CRT, and a control circuit.

  The road map data includes link data and node data for representing roads on the map by links and nodes. The link data and node data include link start and end coordinates, link length, width, etc. Contains information. The navigation device 90 receives a command from the vehicle control ECU 100, specifies the coordinates (latitude and longitude) of the current position of the host vehicle, and curves that exist within a predetermined distance in front of the road of the host vehicle and the current position of the host vehicle. Output road link data and node data.

  The vehicle control ECU 100 is mainly configured as a microcomputer, and each includes a known CPU, ROM, RAM, I / O, and a bus connecting them. The vehicle control ECU 100 uses a brake discriminant KdB_c (KdB_c_t), which will be described later, to determine the deceleration control start timing when entering the curve road, and when the vehicle travels the curve up to the entrance of the curve. By executing deceleration control that decelerates the host vehicle to the target travel relative speed calculated from the target lateral G (Gy_t) as the target, it realizes deceleration control that matches the driver's sense of danger when entering the curve. .

  Hereinafter, as shown in FIG. 2, the deceleration control process executed by the vehicle control ECU 100 will be described with reference to the flowchart shown in FIG. This deceleration control process is executed when the road ahead in the traveling direction of the host vehicle is curved, and is started by receiving the curve information via the road-to-vehicle communication device 60.

  First, in step S1 of FIG. 3, curve information including the curve R, the road friction coefficient μ in the curve, the coordinates of the entrance / exit point of the curve (latitude and longitude), the width of the curve, the number of lanes, the width for each lane, and the like is acquired. In addition, vehicle information including the speed Vs0 of the own vehicle, the coordinates (latitude and longitude) of the current position of the own vehicle is acquired.

  In step S2, as shown in FIG. 2, the distance D_c from the entrance point (straight line end position) of the curve in front of the vehicle to the road boundary outside the curve or a road accessory provided in the vicinity thereof is expressed by Equation 1. calculate. Note that L is a lateral position with respect to the lane centering on the own vehicle.

D_c = [R ² − (R−L) ² ] ^1/2 ... Formula 1
In step S3, after calculating the distance D from the own vehicle to the road boundary which is a curve departure point outside the curve in front of the own vehicle or a road accessory provided in the vicinity thereof, the curve of the curve from the own vehicle to the front of the own vehicle is calculated. The distance D_s to the entrance point (straight line end position) is calculated by Equation 2.

D_s = D−D_c Equation 2
In step S4, the current value (KdB_c_p) of the corrected approaching / separating state evaluation index KdB_c taking into account the speed of the road boundary or road accessory and the vehicle is calculated according to Equation 3. Note that Vr_p (= −Vs0) in Equation 3 is a relative speed between a road accessory provided near or at the road boundary outside the curve and the host vehicle, and | −2 × Vr_p | in Equation 3 is ( -2 x Vr_p) is the absolute value.

KdB_c_p = 10 × log ₁₀ {| −2 × Vr_p | / (D ³ × 5 × 10 ⁻⁸ )} Equation 3
Since this corrected approaching / separating state evaluation index KdB_c is described in Japanese Patent Application No. 2007-7473 filed earlier by the applicant of the present application, its outline will be briefly described. When there is a curve in the traveling direction of the vehicle, the driver of the vehicle usually turns the vehicle into a curve from a visual area change of a road accessory provided at or near the road boundary outside the curve. It is determined whether the vehicle is approaching or away from the curve, and an accelerator operation or a brake operation is performed based on the determined result.

  Therefore, based on an index (see paragraph 0047 of Japanese Patent Application No. 2007-7473) indicating a visual area change of a road accessory provided at or near the road boundary outside the curve, which is a criterion for determining the driving operation of the driver. By executing the deceleration control at the same time, an index that becomes a deceleration start timing corresponding to the driver's sense of danger when entering the curve is obtained as a corrected approaching / separating state evaluation index KdB_c.

  In step S5, it is determined whether or not the current value (KdB_c_p) of the corrected approaching / separating state evaluation index KdB_c calculated in step S4 exceeds the brake discriminant KdB_c (KdB_c_t) in order to determine whether or not to start deceleration of the host vehicle. to decide. If an affirmative determination is made in step S5, the process proceeds to step S6. If a negative determination is made, the process proceeds to step S1, and the above-described process is repeated. The brake discriminant KdB_c (KdB_c_t) is calculated from Equation 4.

KdB_c (KdB_c_t) = − 23.76 × log ₁₀ D + 76.96 Equation 4
The brake discriminant KdB_c (KdB_c_t) is determined by the preceding vehicle (in this embodiment, the curve in this embodiment) as described in Japanese Patent Application No. 2007-7473 (see paragraphs 101 to 104) filed earlier by the applicant of the present application. In the situation where the vehicle is approaching the road accessory outside or near the road boundary), the brake operation is performed at the last minute timing where the brake can be controlled so that the test driver does not collide with the pioneer. It is an approximate expression showing the relationship between the corrected approaching / separating state evaluation index KdB_c when teaching to start and experimenting and the distance to the preceding vehicle at the start of the brake operation. Therefore, by starting the execution of deceleration control at the timing that uses this approximate expression as a threshold value, in general drivers, the brake operation is intervened from outside the regular area in most cases, so that the vehicle deviates from the curve. No longer enters the area.

  In step S6 of FIG. 3, a target lateral G (Gy_t) that is a target when traveling on a curve corresponding to the road surface friction coefficient μ in the curve is calculated with reference to the curve information. The target lateral G (Gy_t) may be calculated based on the Coulomb friction law so that the lateral force of the tire during the steering operation of the host vehicle can be secured when traveling on a curve.

In step S7, the target travel relative speed Vr_Gy_t between the vehicle and the road accessory provided at or near the road boundary outside the curve, at which the vehicle can turn the curve at the target lateral G (Gy_t), is _expressed by It is set by calculating from 5.

_{Vr_ Gy_t = - (R × Gy_t} ) 1/2 ··· formula 5
In step S8, first, a relative speed (target approach relative speed _{Vr_Gy_t} + v) to be the target of the host vehicle at a point before the entrance point of the curve is calculated. The target approach relative speed Vr_ _{Gy_t} + v, by adding the arbitrary relative velocity v with respect to the target traveling relative speed Vr_ _{Gy_t,} is set to exceed the target travel relative speed Vr_ _{Gy_t} only the relative velocity v.

FIG. 4 (a) shows the corrected approach / separation state evaluation index KdB_c of Equation 3 above with the distance D from the vehicle to the road boundary or a road accessory provided in the vicinity thereof as the horizontal axis. Or the relative speed with the road accessory provided in the vicinity is represented as a vertical axis | shaft. In step S8, the distance from the front of a point than the entrance point of the curve when viewed from the vehicle at the target approach relative speed Vr_ _{Gy_t} + v in the FIGS. 4 (a) to road boundary or the road associated object, which is provided near the D_Vr seeking _{Gy_t} + v, the coordinate point _{(D_Vr Gy_t + v, Vr_ Gy_t} + v) and the coordinate point (d_c, Vr_ _{Gy_t)} obtaining the connecting I bond lines and a straight line (or a curve).

In step S9, the brake discriminant KdB_c (KdB_c_t) indicated by the solid and dotted lines in FIG. 4B is provided at or near the road boundary from a point before the entrance of the curve as viewed from the own vehicle. The distance D_Vr _{Gy_t} + v to the road accessory and the distance D_c from the entrance point of the curve to the road accessory at or near the road boundary (hereinafter referred to as the curve entry section, Cc of FIG. 2) Brake discriminant in (section) is calculated from the connecting line obtained in step S8. That is, it is calculated by substituting the bond line variables (D, Vr) into Equation 3.

  As a result, as shown by the double line in FIG. 4B, the corrected approaching / separating state evaluation index KdB_c in the curve approaching section that is steeper than the increasing gradient of the brake discriminant KdB_c (KdB_c_t) set in advance is In the curve entry section, the discriminant used for the brake start determination is switched (changed) to the corrected approach / separation state evaluation index KdB_c in the curve entry section.

  Therefore, as shown in FIG. 5 (a), the brake start determination is performed using the brake discriminant KdB_c (KdB_c_t) indicated by the solid line until the curve approach section is reached, as shown in FIG. 5 (b). In the curve entry section, the brake start determination is performed by the brake discriminant represented by the double line.

As a result, as shown in FIG. 6A, when the host vehicle enters the curve road, the speed of the host _{vehicle is} the target travel relative speed Vr_Gy_t when the vehicle travels on the curve road before reaching the curve entry section. the now is decelerated to the target, in the curve entry segment, comprising the target approach relative speed Vr_ _{Gy_t} + v exceeding the target travel relative speed Vr_ _{Gy_t} to be decelerated to a target. In addition, as shown in FIG. 6B, the KdB_c current value (KdB_c_p) changes to a point on the brake discriminant _{KdB_c at} the distance D_Vr _{Gy_t} + v until reaching the curve approach section, and enters the curve. Within the section, the point on the brake discriminant indicated by the double line at the distance D_c changes to the target.

In step S10 of FIG. 3, the target deceleration Gx of the host vehicle is calculated from Equation 6 and output to the VSC_ECU 10 via the in-vehicle LAN. Accordingly, the VSC_ECU 10 controls the brake actuator so that the target deceleration Gx is generated in the host vehicle. Incidentally, T of Equation 6, the current and the relative speed Vr_p of the vehicle, the difference between the target relative speed Vr_t (until reaching the curve entry segment is a Vr_ _{Gy_t,} the Vr_ _{Gy_t} + v is in the curve entry segment) This is a divisor for conversion to the target vehicle deceleration Gx, which is set appropriately.

Gx = (Vr_p−Vr_t) / T Equation 6
In step S11, it is determined whether or not the relative speed Vr_p of the host vehicle is lower than the target relative speed Vr_t. Here, when an affirmative determination is made, the present process is terminated, and when a negative determination is made, the process proceeds to step S1 and the above-described process is repeated.

  With this driving support system operating in this way, when the vehicle travels on a curve road, the speed Vs0 of the vehicle is sufficiently decelerated to a point before the entrance point of the curve, and in the curve approach section, Since the degree of deceleration is relaxed, it is possible to execute control that matches the driver's sense of danger when entering the curve.

  In the present embodiment, curve information is acquired by road-to-vehicle communication with a roadside communication device (roadside infrastructure), but is not limited to this method, either a radar device or a navigation device, or You may make it acquire by combining the curve information obtained from them.

It is a block diagram which shows the whole structure of a vehicle control apparatus. It is a figure for demonstrating the condition where the own vehicle approachs the curve road of the curve R. FIG. 5 is a flowchart for illustrating deceleration control processing executed by a vehicle control ECU 100. (A), (b) is a figure for demonstrating the calculation method of the brake discriminant in a curve area. (A) is a figure for demonstrating the brake start determination performed before reaching | attaining a curve approach area, (b) is a figure for demonstrating the brake start determination performed in a curve approach area. (A) is a diagram for explaining a change in the vehicle relative speed Vr_p respect to the target traveling relative speed Vr_ _{Gy_t} and target travel relative speed Vr_ _{Gy_t} when traveling a curve road, (b) is KdB_c now It is a figure for demonstrating the change of a value (KdB_c_p).

Explanation of symbols

10 VSC_ECU10
50 ENG_ECU
60 Road-to-vehicle communication device 70 Radar 90 Navigation device 100 Vehicle control ECU

Claims (1)

A distance acquisition means for acquiring a distance between the vehicle and a road accessory provided on or near a road boundary of a curved road located in front of the vehicle, located on an extension line of the vehicle traveling direction;
Speed acquisition means for acquiring the speed of the vehicle;
A relative speed detecting means for detecting a relative speed between the road boundary or the road accessory and the vehicle;
The road boundary or the road accessory is approached as an index indicating the approaching / separating state of the vehicle with respect to the road boundary or the road accessory in consideration of the speed of the road boundary or the road accessory and the own vehicle. An evaluation index calculating means for calculating a corrected approaching / separating state evaluation index that increases as the relative speed increases and becomes steeper as the distance from the road boundary or the road accessory decreases at each relative speed;
A radius of curvature acquisition means for acquiring a radius of curvature of the curve road;
Target running relative that sets a target running relative speed when the vehicle runs on the curved road from a curvature radius of the curved road and a target lateral acceleration that is targeted when the own vehicle runs on the curved road Speed setting means;
Based on the target travel relative speed, a target approach relative speed to be set as a target of the vehicle at a point before the entrance point of the curve road is set, and the relative speed exceeding the target travel relative speed Target approach relative speed setting means for setting the target approach relative speed,
Using the target travel relative speed and the target approach relative speed, an increasing gradient of the corrected approach / separation state evaluation index in a curve approach section from a point before the entrance of the curve road to the entrance point of the curve road is preliminarily determined. A curve approach section threshold value setting means for setting a threshold value of the correction approach / separation state evaluation index in the curve approach section, which is steeper than the increasing gradient of the threshold value of the set correction approach / separation state evaluation index;
Until the vehicle reaches the curve approach section, it is determined whether the corrected approaching / separating state evaluation index calculated by the evaluation index calculating unit exceeds a threshold value of the preset corrected approaching / separating state evaluation index, Whether the corrected approaching / separating state evaluation index calculated by the evaluation index calculating means exceeds the threshold value of the corrected approaching / separating state evaluation index in the curve approaching section set by the curve approaching section threshold setting means within the curve approaching section Threshold determination means for determining
If the threshold value determining means determines that the threshold value exceeds the threshold value, the target running relative speed is determined from the target running relative speed, the target approaching relative speed, and the own vehicle relative speed until the own vehicle reaches the curve approaching section. A target deceleration calculating means for calculating a target deceleration for decelerating the host vehicle to a speed, and calculating a target deceleration for decelerating the host vehicle to the target approach relative speed in the curve approach section;
Vehicle control means, comprising: vehicle control means for performing deceleration control so that the deceleration generated in the host vehicle becomes the target deceleration.

Images