JP2007026289A - Vehicle control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle control system for preventing deviation from a traffic lane depending on the level of danger of roadside. <P>SOLUTION: The vehicle control system comprises a vehicle position estimating means for estimating the position of the vehicle, a roadside situation detecting means for detecting the roadside situation in front of the traveling direction of the vehicle position estimated by the vehicle position estimating means, a running position detecting means for detecting the vehicle position to the running lane, a judging means for judging an alarming method based on the deviation of the vehicle position from the running lane detected by the running position detecting means and the roadside situation detected by the roadside situation detecting means, and an alarming means for alarming depending on the alarming method judged by the judging means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle control device that controls a vehicle, and more particularly to a vehicle control device that controls a vehicle so as to prevent the vehicle from deviating from a traveling lane.

  There are known lane departure warning devices for estimating the shape of the road in the direction of the course and issuing a warning when the vehicle is likely to depart from the lane, and lane keeping assist for assisting driving along the lane ( For example, see Patent Document 1.)

In such vehicle control, a guide line to be traveled and a travel position of the host vehicle with respect to the guide line are detected from an image obtained by photographing a road in the traveling direction. When a possibility that the vehicle deviates from the guide line is generated, an alarm sound or the like is generated to alert the driver, or the driver is assisted by steering in a direction to prevent the departure.
JP 2001-175999 A

  However, the lane departure restraint device described in Patent Document 1 performs departure prevention control according to the amount of deviation from the guide line that is the target of travel, and does not consider the degree of danger in the case of departure. . When driving on roads, there are various situations outside the road, such as the width of the shoulders and the topography outside the road, so control for deviation should be performed in consideration of the risk of departure from the driving lane according to the situation outside the road. Is desirable.

  In view of the above problems, an object of the present invention is to provide a vehicle control device that prevents lane departure according to the degree of danger outside the road.

  In order to solve the above problems, the present invention provides vehicle position estimation means for estimating the position of a vehicle, and road outside situation detection means for detecting a situation outside the road ahead of the vehicle position in the traveling direction of the vehicle position estimated by the vehicle position estimation means. Travel position detection means for detecting the travel position of the vehicle with respect to the travel lane, the amount of deviation of the travel position from the travel lane detected by the travel position detection means, and the situation outside the road detected by the road outside condition detection means And a warning means for giving a warning based on the above.

  ADVANTAGE OF THE INVENTION According to this invention, the vehicle control apparatus which aims at the deviation prevention of a lane according to the danger degree outside a road can be provided.

  In one embodiment of the present invention, the warning means executes the warning earlier when the danger level outside the road is high than when the danger level is low.

  According to the present invention, when the risk outside the road is high, a warning can be given early, so that the possibility of deviating outside the road with a high risk can be reduced.

  Further, in one embodiment of the present invention, the warning means is characterized in that when the danger level of the situation outside the road is high, the alarm is activated more than when the danger level is low.

  According to the present invention, a strong warning can be given when the degree of danger outside the road is high, so the possibility of deviating outside the road with a high degree of danger can be reduced.

  It is possible to provide a vehicle control device that prevents lane departure according to the degree of danger outside the road.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a functional block diagram of a vehicle control device 10 of the present embodiment. The vehicle control device 10 is connected to a camera 11 that captures the front in the traveling direction of the vehicle, and uses an image processing unit 12 that processes an image in front of the vehicle captured by the camera 11 and a processing result of the image processing unit 12. Travel lane detection means 13 for detecting a travel lane (travel lane). The traveling lane detecting means 13 is a traveling position detecting means for detecting the traveling position of the host vehicle with respect to a guide line (for example, a line connecting approximately the center of the traveling lane) on which the vehicle travels along the traveling lane. 21. Therefore, the travel position detecting means 21 can determine how much the host vehicle deviates from the guide line to be traveled.

  Moreover, the vehicle control apparatus 10 has the navigation system 17, and can estimate the vehicle position on the road of a vehicle. The navigation system 17 has a road map DB 19 storing road information, and refers to the road map DB 19 based on signals input from the GPS receiver 14, the gyro compass 15 and the vehicle speed sensor 16. Thereby, road information based on the vehicle position can be used.

  In addition, the road map DB 19 stores a situation outside the road surface (hereinafter referred to as an out-of-road situation), and the out-of-road situation detection means 22 detects an out-of-road situation encountered when the vehicle deviates from the driving lane. To do. Outside the road is an area or space in contact with a road where the vehicle does not normally travel, and refers to situations outside the left and right lanes, such as road shoulders, cliffs, fields, and the like.

  The determination means 20 determines the warning method according to the off-road situation detected by the off-road situation detection means 22 when the travel position detection means 21 detects that the position of the host vehicle deviates from the travel lane by a predetermined amount or more. To do. The determination result is sent to the vehicle control means 23, the warning means 24 included in the vehicle control means 23 issues a warning by the display device 26 and the speaker 27, and the steering means 25 controls the steering actuator 28 to steer the vehicle. , To prevent departure.

  The vehicle control device 10 is configured by an electronic control unit including a microprocessor, a ROM, a RAM, a communication interface, and the like. The ROM stores a program for performing vehicle control according to the present embodiment, and operates as the vehicle control device 10 when the program is executed by a microprocessor.

  The detection of the traveling lane will be described. The camera 11 is composed of a solid-state imaging device such as a CCD or a CMOS, and is installed, for example, in the vicinity of a room mirror in a vehicle interior to photograph a predetermined range in front of the vehicle. An image photographed by the camera 11 is sent to the image processing means 12.

  The image processing means 12 detects a white line based on the image ahead of the vehicle. FIG. 2 shows an image in front of the vehicle taken by the camera 11. In the image, white lines 50 located on the left and right of the vehicle are photographed.

  The image processing means 12 assumes a plurality of horizontal lines 51 that are equally spaced on the screen, and differentiates the brightness of each horizontal line in the horizontal direction. A normal road surface has low luminance and changes in luminance are small. On the other hand, since the brightness of the white line 50 is higher than that of the normal road surface, when the brightness of the road is differentiated, a positive brightness change at the boundary point from the normal road surface to the white line 50 is detected from the white line 50 to the normal road surface. Differential data in which the luminance change is negative at the boundary point to the road surface is obtained. With respect to the differential data of each horizontal line 51, differential value peaks appear in the order of plus and minus from the left, and combinations where the peak interval is considered to be appropriate as the white line 50 are detected as white lines. Such white line recognition processing is repeated at a required cycle, and the white line recognition is updated each time.

  Note that the image processing unit 12 may detect the white line 50 having a luminance equal to or higher than a predetermined threshold by pattern recognition. If it is a white line, a rectangular region appears upward or downward from the bottom of the image, or a white line appears when a rectangular shape that is equal to or greater than the predetermined threshold is detected using a rectangular pattern. Detect as. By searching a number of such white line candidate points at each of the upper and lower positions of the image, the white line on the road ahead of the host vehicle can be recognized far.

  The traveling lane detection unit 13 sets the approximate center of the white line as the guide line 52 based on the detected white line. Then, the traveling position detection means 21 compares the vehicle center line 53 and the guide line 52 to calculate the deviation amounts δ1, δ2,... Between the guide line 52 and the vehicle center line 53 at predetermined distances from the vehicle or continuously. calculate. The vehicle center line 53 is the vehicle traveling direction based on the steering angle of the steered wheels.

  When the angle formed between the guide line 52 and the vehicle center line 53 at the travel position of the vehicle is α, the shift amount δ is the distance between the angle α formed between the guide line 52 and the vehicle center line 53 and the calculation point of the shift amount. Can be calculated as δ = α × distance.

  The traveling position of the vehicle may be detected by a magnetic nail or a magnetic sensor embedded along the lane. Since the vehicle control apparatus has a navigation system as described below, the amount of deviation from the approximate center of the white line extracted from the road map DB 19 based on the vehicle position estimated by the vehicle position estimation means 18 of the navigation system. δ may be detected.

  Next, estimation of the vehicle position and detection of the situation outside the road will be described. The vehicle position estimation means 18 estimates the current position while correcting the position estimation by GPS (Global Positioning System) navigation and autonomous navigation, and correcting the map matching method. That is, radio waves transmitted from a plurality of (three or more) GPS satellites are received by the GPS receiver 14, and the current position of the vehicle is estimated by GPS navigation based on the arrival time of the radio waves and the position information of the GPS satellites.

  The vehicle position estimation means 18 estimates the current position of the vehicle by autonomous navigation while accumulating the travel route of the vehicle based on information from the vehicle speed sensor 16 and the gyrocompass 15. Then, with respect to the position estimation based on these GPS navigation and autonomous navigation, the current position is finally estimated with high accuracy by a map matching method that associates the road of the road map information extracted from the road map DB 19 with the position of the vehicle.

  The vehicle speed sensor 2 is, for example, a pulse sensor provided on each wheel, and detects the vehicle speed based on the number of pulses detected at predetermined time intervals. The gyrocompass 15 detects the traveling direction of the vehicle based on the lateral G acting on the vehicle and its changing speed.

  The road map DB 19 for storing road map information is composed of a CD, a DVD-ROM, and a hard disk, and stores road map information such as road networks and intersections in association with latitude and longitude. Road map information consists of information related to nodes (points where roads and roads intersect, that is, intersections) and information related to links (roads connecting nodes and nodes) corresponding to the actual road network. Stored in a table-like database.

  The node table has node numbers, coordinates, the number of links flowing out from the nodes, and their link numbers. The link table has a link number, a start node and an end node constituting the link, and a link length. The node number and the link number are determined so as not to overlap each other. Therefore, a road network is formed by following the node number and the link number.

  The road map information stores road information such as the width of the road, the number of lanes, the width of the road shoulder, and the situation outside the road. In addition, road type information such as highways, general national roads, and local roads, and traffic rules such as speed limit, one-way traffic, U-turn prohibition, and the like are stored.

  The off-road situation detecting means 22 extracts the off-road situation from the road map DB 19 based on the estimated vehicle position. FIG. 3 is a diagram illustrating an example of a road and a situation outside the road extracted based on the estimated position of the vehicle. In FIG. 3, a cliff 55 and a field 54 are detected on the right side of the vehicle traveling direction on a one-lane road, and an emergency road shoulder 56 is detected on the left side of the vehicle traveling direction. If the vehicle deviates from the lane in such an off-road situation, the vehicle may be damaged if it deviates to the field 54, and the vehicle may be damaged if it deviates to the cliff 54. It can be expected that there is more possibility of joining the driver and vehicle than deviating.

  If there is an oncoming lane, the oncoming lane will be outside the road if it deviates from the rightmost driving lane to the right. Therefore, the situation outside the road includes the oncoming lane. The lane in which the host vehicle is traveling when there are a plurality of traveling lanes may be determined from the result of map matching performed by the traveling position detection means 21, or an oncoming vehicle is photographed on the right side beyond the detected traveling lane. If the preceding vehicle is photographed on the right or left side beyond the detected white line, it can be determined that it is not at least the rightmost or leftmost traveling lane.

  Then, the determination means 20 determines the danger level based on the direction of deviation between the guide line 52 and the vehicle center line 53 detected by the travel position detection means 21 and the situation outside the road detected by the road outside situation detection means 22. judge.

  FIG. 4A shows a level table showing the relationship between the off-road situation and the danger level that the determination means 20 has. In FIG. 4A, the off-road situation is stored in association with High and Low as the danger level. As an example, cliffs, seas, rivers, and opposite lanes are stored as danger levels High, and paddy fields, fields, and road shoulders are stored as danger levels Low. The determination means 20 can acquire whether the danger level is High or Low by extracting the situation outside the road from the road map DB 19 and referring to the level table. The danger level may be classified more finely.

  The determination means 20 has a warning determination table that defines a warning method for the driver in association with the danger level. FIG. 4B shows an example of the warning determination table. In the warning determination table, alarm levels (levels 1 to 4) are defined based on the danger level (High and Low) and the reference value (δa and δb (where δa <δb)) of the deviation amount. Note that the alarm level may be determined using the distance to the outside of the road instead of the amount of deviation from the guide line.

  The alarm level represents the size and type of alarm or the distance (alarm timing) at which an alarm is issued. For example, level 1 warns at a low alarm sound and late alarm timing, level 2 warns at a low alarm sound and early alarm timing, level 3 warns at a high alarm sound and late alarm timing, Level 4 represents a warning with a loud alarm sound and an early alarm timing. The type of alarm sound may be changed for each level.

  That is, according to FIG. 4B, when the danger level outside the road is Low and the deviation amount δ is δa <δ <δb, a level 1 warning is issued, and the danger level outside the road is Low and the deviation amount δ is If it is greater than δb, a level 2 warning is issued. If the danger level outside the road is high and the deviation δ is δa <δ <δb, a level 3 warning is issued, and the danger level outside the road is high and the deviation is high. If δ is greater than δb, a level 4 alarm is issued.

  Accordingly, the determination means 20 can determine that the higher the danger level of the off-road situation, the larger the alarm sound is heard and the earlier the alarm timing.

  When the determination unit 20 determines to give a warning, the vehicle control device 23 controls the warning unit 24 to give a warning to the driver. Since the determination unit 20 sends the volume, type, and timing of the alarm sound to the vehicle control unit 23 based on the alarm level extracted from the warning determination table, the warning unit 24 issues a warning from the display device 26 or the speaker 27. The display means 26 is a liquid crystal, organic EL, HUD (Head Up Display), etc., for example. The alarm sound continues to be heard as long as the conditions of the warning determination table are satisfied, and when the alarm level rises while traveling, the volume of the alarm sound is switched according to the alarm level.

  In addition, for example, when the driver is displaying a navigation road map screen and the determination table 20 determines that a warning is issued, the road map screen may be switched to a warning character or the screen may be blinked. The driver may be warned.

  Further, when the possibility of deviating from the lane increases, the steering means 25 controls the steering actuator 28 to prevent the lane from deviating. The steering actuator 28 is an actuator that applies a steering control torque to the steering system separately from the steering torque applied by the driver.

  The steering means 25 controls the steering actuator 28 with a steering torque set based on the deviation amount δ. The steering torque is limited to a magnitude that does not hinder the driver's steering operation, that is, a magnitude that the driver can easily overcome. Therefore, when the steering control torque is applied in a direction to avoid the departure when the vehicle is likely to deviate from the lane, the driver can perform the steering operation in the direction deviating from the lane. As a result, steering for retracting the vehicle out of the driving lane can be performed, and even if the steering control torque is activated during the lane change, the lane change is not hindered.

  In addition to the steering actuator 28, a vibration actuator that vibrates the handle 20 may be provided. The vehicle control means 23 can alert the driver that there is a possibility of deviating from the lane by causing the handle 20 to vibrate with reference to the warning determination table.

  Further, the vehicle control means 23 may not only prevent the departure of the lane by sounding an alarm or steering by the steering actuator 28 but also brake the vehicle. In this case, for example, when the amount of deviation between the guide line and the vehicle center line is larger than a predetermined value, the brake actuator is controlled before deviating from the lane to decelerate the vehicle, thereby reducing the possibility of deviation. it can.

  That is, the warning determination table may prescribe warning methods based on the vibration of the steering wheel, steering by the steering actuator 28, braking of the vehicle, and the like according to the danger level and the deviation amount.

  Based on the above configuration, a process in which the vehicle control device controls the vehicle according to the situation outside the road will be described based on the flowchart of FIG. The process of FIG. 5 starts when the vehicle starts running, for example, and is repeated unless the vehicle control device is stopped.

  Since the camera 11 captures an image forward in the traveling direction at a predetermined frame rate (for example, 10 to 30 frames / second), the image processing unit 12 detects a white line for each frame. The travel lane detection means 13 obtains a guide line along the travel lane (S11).

  Next, the traveling position detection means 21 obtains an angle α formed by the vehicle center line with respect to the guide line, and detects the amount of deviation between the guide line and the vehicle position for each predetermined distance from the vehicle (S12).

  Since the position of the host vehicle is periodically acquired by the vehicle position estimating means 18, the outside road condition detecting means 22 detects a situation outside the road ahead of the vehicle from the road map DB 19. The judging means 20 refers to the level table based on the situation outside the road, and acquires the danger level of the situation outside the road (S13).

  Next, the determination means 20 determines whether or not the deviation amount δ at a predetermined distance (for example, 30 m) from the vehicle is larger than the deviation amount reference value δa (S14). Since the deviation amount δa is set to a value that is not so large as to deviate from the lane, if the deviation amount δ is smaller than the reference value δa (Yes in step S14), the alarm is not heard or the alarm is heard. Stop (S15).

  If the deviation amount δ is larger than the deviation amount reference value δa (No in step S14), the determination means 20 refers to the warning determination table, extracts the alarm level, and controls the vehicle based on the alarm level (S16).

  For example, when the deviation amount δ of the predetermined distance from the vehicle is δa to δb and the danger level of the off-road situation in the departure direction is High, a level 3 warning is heard. The warning means 24 sounds an alarm according to the level 3 volume and the alarm timing. Further, for example, when the deviation amount δ of the predetermined distance from the vehicle is δ> δb and the danger level of the off-road situation in the departure direction is High, a level 4 warning is heard. The warning means 24 sounds an alarm according to the level 4 volume and the alarm timing.

  As described above, according to the vehicle control device of the present embodiment, the alarm can be heard by controlling the intensity and timing of the alarm according to the situation outside the road. If the danger level when the vehicle deviates from the driving lane is large, the warning timing can be advanced and a strong warning can be issued, so the possibility of deviating from the lane can be reduced. The warning to the driver includes not only sound but also notification by bodily vibration, light, or the like.

It is a functional block diagram of a vehicle control device. It is an example of the image ahead of the vehicle image | photographed with the camera. It is a figure which shows an example of the road extracted based on the estimated position of a vehicle, and a road exterior condition. It is a table which shows the relationship between an off-road situation and a danger level, and the relationship between an alarm level, a danger level, and deviation | shift amount. It is a flowchart figure which shows the flow of the process which a vehicle control apparatus controls a vehicle according to the condition outside a road.

Explanation of symbols

10 Vehicle control device 11 Camera
12 Image processing means 13 Traveling lane detection device 18 Vehicle position estimation means 19 Road map DB
20 Judgment means 21 Traveling position detection means 22 Outside road condition detection means 23 Vehicle control means 24 Warning means 25 Steering means

Claims (3)

Vehicle position estimating means for estimating the position of the vehicle;
An out-of-road situation detecting means for detecting an out-of-road situation in the traveling direction of the vehicle position estimated by the vehicle position estimating means;
Traveling position detection means for detecting the traveling position of the vehicle with respect to the traveling lane;
Warning means for warning based on the amount of deviation of the travel position from the travel lane detected by the travel position detection means and the situation outside the road detected by the outside road condition detection means;
A vehicle control device comprising: The warning means executes a warning earlier when the danger level outside the road is high than when the danger level is low,
The vehicle control device according to claim 1. The warning means increases the alarm operation when the risk of off-road situations is high, compared to when the risk is low,
The vehicle control apparatus according to claim 1 or 2, wherein

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