JP2008174092A - Speed control device - Google Patents

Abstract

A safer inter-vehicle distance is maintained according to a driver's condition even when the driver is driving aside.
A speed control device includes a vehicle speed sensor that detects a speed of the vehicle, an inter-vehicle distance sensor that measures an obstacle distance to an obstacle in the traveling direction of the vehicle, and a holding based on the speed of the vehicle. When the obstacle distance measured by the control unit 100 for setting the reference distance to the obstacle to be performed and the inter-vehicle distance sensor 130 is smaller than the reference distance set by the control unit 100, the braking device 150 of the vehicle is operated. The control unit 100 includes a braking control unit 40 to be operated and a CPU 10 that determines whether or not the driver of the vehicle is driving aside, and the control unit 100 is determined that the driver is performing a side-by-side driving by the CPU 10. In addition, the reference distance is made larger than when it is determined that the driver is not driving aside.
[Selection] Figure 1

Description

  The present invention relates to a vehicle speed control apparatus. More specifically, the present invention relates to a speed control device for auto cruise control that follows a preceding vehicle.

  As a vehicle speed control device, for example, a speed control device disclosed in Patent Document 1 is used. This speed control device detects the distance to an obstacle ahead, and when this distance becomes smaller than a predetermined distance, the vehicle speed is reduced so that the vehicle can stop before the obstacle. .

  Further, for example, alarm devices disclosed in Patent Document 2 and Patent Document 3 are known. These alarm devices issue an alarm when the driver is asleep or lacks concentration. In the technique of Patent Document 2, an inter-vehicle distance from a preceding vehicle ahead is calculated, and an aside lookable time for issuing an alarm based on the inter-vehicle distance is set. Patent Document 3 discloses a technique for issuing an alarm when the inter-vehicle distance is further reduced in a side-by-side state.

  The technology of Patent Document 1 estimates the position of the host vehicle after a set time that is shorter than the time required for avoiding a collision with the target obstacle by the driver's operation from the start of braking, and the position of the target obstacle. After the set time elapses, it is determined whether or not the vehicle position matches the estimated obstacle position. In addition, the driver's eyeballs and eyelids are monitored, and the driver's arousal level is detected by measuring physiological phenomena such as the driver's brain waves, pulse, and skin resistance. It describes changing the time required for collision avoidance by operation.

Patent Document 4 describes a technique for performing a rear-end collision warning according to the actual traveling characteristics of a vehicle. The technique of Patent Document 4 detects the distance to the preceding vehicle, the speed of the own vehicle, and the relative speed between the own vehicle and the preceding vehicle, and based on the speed of the own vehicle and the relative speed with respect to the preceding vehicle, A set inter-vehicle distance from the vehicle is calculated to predict a rear-end collision situation in which the host vehicle collides with a preceding vehicle. Then, the set inter-vehicle distance is corrected based on the rear-end collision situation, and the rear-end collision risk degree between the host vehicle and the preceding vehicle is calculated based on the calculated set inter-vehicle distance or the corrected set inter-vehicle distance and the distance to the preceding vehicle. judge. Further, it is described that the set inter-vehicle distance calculated by the set inter-vehicle distance calculation means is increased when a driver's side-viewing action is detected.
JP-A-5-181529 JP 2002-219968 A Japanese Patent Laid-Open No. 10-181380 JP 2004-21815 A

  A so-called auto-cruise control (hereinafter referred to as ACC) technology that automatically controls the speed when a vehicle travels to assist the driver has been put into practical use. In ACC, there is a method called tracking ACC that controls the speed by following the vehicle ahead.

  Here, in patent documents 1-4, the case where a driver's side-arm is detected in the operation | movement of follow-up ACC is not considered. Moreover, although the technique of patent document 1 controls the distance between vehicles and the vehicle speed as the change according to a driver | operator's arousal level, it does not consider the case where the driver is driving aside. When the ACC is not working, the driver unconsciously decelerates, for example, by loosening the accelerator when looking aside, so the inter-vehicle distance tends to increase naturally. However, when the ACC is working, the inter-vehicle distance is kept constant even when the driver is awake and driving aside. was there.

  The present invention has been made in view of the above-described problems, and realizes a speed control device that maintains a safer inter-vehicle distance according to the driver's condition even when the driver is driving aside. For the purpose.

  In order to achieve the above object, a speed control device according to a first aspect of the present invention includes a vehicle speed detection unit that detects a vehicle speed, and a distance that measures a preceding vehicle distance to a preceding vehicle in the traveling direction of the vehicle. Measuring means; distance setting means for setting a reference distance to the preceding vehicle to be held based on the speed of the vehicle; and causing the vehicle to follow the preceding vehicle and the preceding measured by the distance measuring means. Control means for operating the braking means and / or acceleration means of the vehicle so that the vehicle distance is larger than the reference distance set by the distance setting means, and whether the driver of the vehicle is driving aside And the distance setting means determines the reference distance when the driver is sideways driving when the driver determines that the driver is looking aside. Set the second reference distance greater than the first reference distance when it is determined that no operation, characterized in that.

  Preferably, the speed control device includes: an imaging unit that captures an image of the driver's face area; and a gaze direction detection unit that detects a gaze direction of the driver from the image of the face area. The determining means determines that the driver is looking aside when the driver's line-of-sight direction detected by the line-of-sight direction detecting means does not match the traveling direction of the vehicle.

  Further, the aside look determining means may determine that the driver is looking aside when the driver's gaze direction detected by the gaze direction detecting means does not coincide with the traveling direction of the vehicle continuously for a predetermined time.

  Further, the aside look determining means changes a predetermined time for determining the aside look driving based on any combination of the vehicle speed, acceleration, yaw rate, steering angle and relative speed of the obstacle with respect to the vehicle. It is good also as composition to do.

  Preferably, when the driver's line-of-sight direction detected by the line-of-sight direction detection unit faces the direction of the indoor rear-view mirror or the outdoor rear-view mirror of the vehicle within a predetermined time range. It is characterized by not judging it as an aside.

  The distance setting means may be configured to set the reference distance based on any combination of the speed, acceleration, yaw rate, steering angle, and relative speed of the obstacle with respect to the vehicle.

  The distance setting means sets the second reference distance as the reference distance once the reference distance is set to the second reference distance, regardless of the determination result of the armpit determination means. May be.

  More preferably, the distance setting means sets the second reference distance as the reference distance until an operation of the acceleration adjusting means of the vehicle is detected after the reference distance is once set to the second reference distance. Set.

  According to the present invention, it is possible to maintain a safer vehicle-to-vehicle distance according to the driver's condition even when the driver is performing a side look driving.

[Embodiment 1]
Hereinafter, a vehicle speed control apparatus according to an embodiment of the present invention will be described.
As shown in FIG. 1, the speed control device 1 according to the present embodiment includes a control unit 100, a vehicle speed sensor 110, an indoor camera 120, an inter-vehicle distance sensor 130, an alarm device 140, a braking device 150, It is comprised from the accelerator apparatus 160 and the accelerator pedal operation detection apparatus 180. FIG.

  The speed control device 1 is a device that performs braking control of a vehicle when the distance to an obstacle ahead is equal to or less than a predetermined distance. The speed control device 1 determines whether the driver is driving aside. When it is determined that the driver is looking aside, the reference distance to be held to the obstacle in the traveling direction, particularly the preceding vehicle, is set larger than that when the driver is not looking aside. At the same time, an alarm may be generated in the alarm device. The control unit 100 includes a CPU (Central Processing Unit) 10, a RAM (Random Access Memory) 20, a ROM (Read Only Memory) 30, a braking control unit 40, an alarm control unit 50, and an accelerator control unit 60. Is done.

  The CPU 10 reads the control program of the control unit 100 from the ROM 30 and executes it.

  The RAM 20 functions as a work temporary storage area for the CPU 10. A non-volatile memory may be provided to retain the memory when the speed control device 1 is powered off.

  The ROM 30 stores the control program of the control unit 100 and various setting values. The set values are a reference distance to be held to the preceding vehicle, a line-of-sight direction of the rear view mirror, an allowable angle in the line-of-sight direction, a limit time for side-by-side discrimination, and the like.

  The distance until the vehicle stops from the running state, or the distance necessary to safely avoid obstacles ahead becomes longer as the vehicle speed increases, so the reference distance is set according to at least the vehicle speed Is done. The set value of the reference distance may be stored in a table format corresponding to the vehicle speed, or may be stored by a calculation formula calculated from the vehicle speed. In addition, the set value includes a reference distance (second reference distance) in the case of aside driving. The reference distance (second reference distance) in the case of the side-view driving is expressed as a distance obtained by adding a predetermined distance to the reference distance (first reference distance) in the case of not doing so. When the reference distance is stored in a table format with respect to the vehicle speed, the distance added to the first reference distance may be stored, or the first reference distance and the second reference distance may be stored. In the case of driving aside, the distance that the vehicle travels before the danger is recognized increases, so the distance to be added to the first reference distance is also at least a value corresponding to the vehicle speed.

  The added distance (or the second reference distance) in the case of the first reference distance and the side-view driving is not only the vehicle speed, but also the vehicle acceleration, yaw rate, steering angle, and relative speed of the obstacle in the traveling direction of the vehicle relative to the vehicle. You may set according to the conditions which combined etc. For example, when the vehicle is accelerating, a larger inter-vehicle distance is required, so the reference distance is increased. Also, when the vehicle is turning, such as when the vehicle is yawing or when there is a steering angle, a longer distance is required for stopping or avoiding operation compared to straight traveling at the same vehicle speed, Increase the reference distance. Further, the reference distance may be changed depending on the relative speed with the preceding vehicle. By setting the reference distance according to the traveling state of these vehicles and the situation of the preceding vehicle, the operation of the follow-up ACC becomes smoother.

  Furthermore, the reference distance may be changed according to the road surface condition, particularly the slip ratio between the road surface and the tire. The slip ratio between the road surface and the tire can be detected by, for example, a difference in rotational speed between the driving wheel and the driven wheel when a driving force is applied to the driving wheel.

  The speed control device 1 basically determines that the driver is looking aside when the driver's line-of-sight direction deviates from the traveling direction by a predetermined angle or more. However, the driver needs to drive while paying attention to various things other than the traveling direction (particularly the preceding vehicle) while traveling. For example, traffic lights, road signs, road markings, side traveling vehicles, oncoming vehicles, pedestrians, road surfaces, road boundaries, and speedometers. When the direction other than the traveling direction is viewed in a short time, it is excluded from the side-view driving. In order to exclude the case where the direction other than the traveling direction is viewed for a short time from the look-ahead operation, the angle determined to be within the traveling direction and the allowable time to be excluded from the look-ahead operation are stored in the ROM 30 as set values.

  The permissible time to be excluded from aside driving when visually recognizing a direction other than the traveling direction for a short time is not constant, and it is desirable to vary according to the state of the vehicle, the other vehicle, or the surrounding situation. For example, when the speed of the vehicle is slow, the permissible time is set to be relatively long to reduce the feeling of nuisance felt by the driver or to smooth the traffic. When traveling at high speeds, the permissible time is shortened to ensure safety. In addition, when the vehicle is turning, or when the road surface is slippery, the allowable time is shortened. When the preceding vehicle is approaching, the allowable time is shorter than when the preceding vehicle is moving away. Therefore, for example, the allowable time is changed according to the vehicle speed, acceleration, yaw rate, steering angle, relative speed of the preceding vehicle with respect to the vehicle, and the like.

  The rear view mirror includes an indoor rear view mirror (also referred to as a room mirror) and a door mirror or a fender mirror that is an outdoor rear view mirror. The driver may view the rear view mirror while driving to confirm safety. Therefore, when the rear view mirror is viewed for a short time, it is not determined to be a side-viewing operation. In order to exclude the case where the rear view mirror is viewed for a short time from the side-viewing operation, the line-of-sight direction of the rear view mirror and the allowable time are stored in the ROM 30 as set values. Strictly speaking, the line-of-sight direction of the rear view mirror changes depending on the physique of the driver. Therefore, the position of the driver's eyes is actually detected, and the line-of-sight direction is calculated from the position of the rear view mirror.

  It is desirable that the permissible time to be excluded from the aside driving when viewing the rear view mirror is also changed according to the state of the vehicle, the other vehicle, or the surrounding conditions. Similarly, the permissible time for mirror viewing is also varied according to, for example, the vehicle speed, acceleration, yaw rate, steering angle, relative speed of the preceding vehicle with respect to the vehicle, and the like.

  In the present embodiment, left and right door mirrors will be described as examples of rear view mirrors. In addition, the gaze allowable limit angle is originally a solid angle (steradian), and the gaze direction is expressed by two angles (for example, a zenith angle and an azimuth angle). I will explain it.

  The set values related to the side-viewing operation determination include, for example, the line-of-sight allowable limit angle θt (rad), the rearview mirror angle, the door mirror allowable limit angle θst (rad), the right door mirror angle θsr (rad), the left door mirror angle θsl (rad), The limit time Tt (msec), the door mirror gazing allowable limit time Tst (msec), and the sideward addition distance Ls (m).

  The line-of-sight allowable limit angle θt is an allowable angle of an angle formed by the line-of-sight direction and the vehicle traveling direction. The sideward allowable limit time Tt is a time during which the driver's line of sight is directed in a direction other than the traveling direction of the vehicle and is not determined to be a sideward driving. The door mirror gaze allowable limit time Tst is a time during which the driver's line of sight faces the door mirror and is not determined to be a side-viewing operation. The addition distance Ls when looking aside is a distance that is added to the reference distance so that the driver can surely stop in front of an obstacle by taking a large reference distance to the obstacle while driving aside. The sideward addition distance Ls is set according to the vehicle speed as described above.

  The right door mirror angle θsr is an angle in the line-of-sight direction in a coordinate system fixed to the vehicle when the driver turns his / her line of sight toward the right door mirror as shown in FIG. The left door mirror angle θsl is an angle in the line-of-sight direction in the coordinate system fixed to the vehicle when the driver turns his line of sight toward the left door mirror. In FIG. 3, the angle in the line-of-sight direction and the door mirror angle are represented as angles with respect to the vehicle front-rear direction. The door mirror allowable limit angle θst is an angle indicating a range in which it is determined that the direction of the driver's line of sight is facing the door mirror. That is, when the absolute value of the difference between the line-of-sight direction angle and the door mirror angle is equal to or smaller than the door mirror allowable limit angle θst, it is determined that the line-of-sight direction faces the door mirror.

  The brake control unit 40 shown in FIG. 1 receives an operation signal for operating the braking device 150 or a stop signal for stopping from the CPU 10, and operates or stops the braking device 150 according to this signal.

  The alarm control unit 50 receives a notification of generating a strong alarm or a notification of generating a weak alarm from the CPU 10, and outputs a strong alarm signal for generating a strong alarm or a weak alarm signal for generating a weak alarm in accordance with these notifications. It transmits to the alarm device 140. Here, the strong alarm is an alarm more important than the weak alarm. For example, in the case of a strong alarm, the alarm volume is larger than that of a weak alarm.

  The vehicle speed sensor 110 detects the current vehicle speed Vc (km / h) and transmits the measured value to the CPU 10.

  The indoor camera 120 is installed at a position where the driver's head near the steering wheel can be photographed, photographs the driver's face image, and transmits the photographed face image to the CPU 10. The number of shots per second and the resolution are sufficient to detect the driver's line-of-sight direction. For example, 30 pictures are taken per second, and the resolution is 240 pixels vertically and 320 pixels horizontally.

  The inter-vehicle distance sensor 130 is a sensor for detecting an obstacle within a predetermined distance in front of the vehicle. The inter-vehicle distance sensor 130 measures the distance to the moving object by physical means using light, electromagnetic waves or sound waves. The inter-vehicle distance sensor 130 is, for example, a millimeter wave radar, a laser distance meter, an ultrasonic distance meter, or the like, and outputs a distance to an object as an electrical signal. The inter-vehicle distance sensor 130 may simultaneously detect the relative speed of the obstacle ahead of the vehicle with respect to the vehicle. The inter-vehicle distance sensor 130 informs the CPU 10 of the detected obstacle distance and relative speed.

  The warning device 140 is a device that issues a warning to the driver by sound or a display, and receives a strong warning signal or a weak warning signal from the warning control unit 50 and generates a strong warning or a weak warning.

  The braking device 150 is a disc-type or drum-type braking device, and operates under the control of the braking control unit 40. The braking device 150 may include a regenerative braking device that recovers kinetic energy as electric energy and / or an exhaust brake.

  The accelerator control unit 60 converts the accelerator control signal of the CPU 10 into a signal for driving the actuator of the accelerator device 160 and outputs the signal. The CPU 10 commands an accelerator control signal to the accelerator control unit 60 so as to keep the distance from the preceding vehicle at or above the reference distance within the set speed limit. The control of the accelerator may include a braking operation using an engine brake that makes the throttle opening substantially zero. In that case, the accelerator control includes a part of the braking control.

  The accelerator pedal operation detection device 180 detects whether or not there is an operation of the accelerator pedal 170 by the driver. The accelerator pedal operation detection device 180 transmits a detection signal to the CPU 10 when the accelerator pedal 170 is operated. As a sensor that detects whether or not the accelerator pedal 170 is operated, for example, a stroke sensor that detects the stroke of the accelerator pedal 170 can be used. For simplicity, a limit switch that detects that the accelerator pedal 170 is depressed more than a certain angle may be used. Although the accelerator pedal operation detection device 180 is not used in the first embodiment, the operation using it will be described in detail in the third embodiment.

  The speed control device 1 has a so-called following auto-cruise function of traveling following a preceding vehicle in a set speed range without stepping on the accelerator pedal 170. That is, the accelerator device 160 is controlled by the accelerator controller 60 and the brake device 150 is controlled by the brake controller 40 so as to follow the vehicle with a predetermined inter-vehicle distance corresponding to the vehicle speed. The following auto-cruise operation of the speed control device 1 will be described with reference to FIG. The speed control device 1 stores a follow-up ACC operation flag FA indicating that the auto cruise control function is operating and a braking device operation flag FB indicating that the braking device 150 is operating in the internal memory. Yes.

  The speed control device 1 turns on the follow-up ACC operation flag FA by turning on an auto-cruise switch (not shown) by the driver, and turns on the follow-up ACC operation flag by turning off the auto-cruise switch by the driver. Turn FA off. The CPU 10 turns on or off the braking device operation flag FB according to the operation of the braking device 150.

  When the following ACC operation flag FA of the speed control device 1 is on and the braking device operation flag FB is off, the following auto-cruise function is operated. However, when the follow-up ACC operation flag FA is on and the brake device operation flag FB is on, the operation of the brake device 150 is prioritized and the follow-up auto-cruise function is stopped.

  The operation of the control unit 100 will be described in detail with reference to FIGS. A flowchart of the control process of the control unit 100 executed by the CPU 10 is shown in FIG. Each time the indoor camera 120 captures an image, the CPU 10 repeatedly executes the side-by-side driving determination process (step S100), the braking control process (step S200), and the alarm device operation process (step S300). For example, when the indoor camera 120 captures 30 images per second, the CPU 10 executes the processing from step S100 to step S300 every 1/30 second.

  In the present embodiment, the aside operation determination process (step S100), the braking control process (step S200), and the alarm device activation process (step S300) are associated with a global variable indicating an aside operation and the like through interprocess communication such as an event. Each of which is an independent process.

  FIG. 5 is a flowchart showing an example of the side-by-side driving determination process (step S100). The aside driving determination process (step S100) is a process of determining whether or not the driver is performing the aside driving by determining whether or not the driver's line-of-sight direction is in the vehicle traveling direction.

  When the CPU 10 starts the look-aside driving determination process (step S100), the CPU 10 first performs an initial setting such as clearing a variable indicating the look-aside driving (step S105). The CPU 10 clears the timers TA and TB and starts measuring time (step S110). The timer TA is an aside timer for measuring the time when the driver is not facing the front. The timer TB is a mirror gaze timer for measuring the time during which the driver is gazing at the direction of the door mirror. These timers measure time in milliseconds, for example.

  Next, the driver's gaze direction is detected from the driver's face image received from the indoor camera 120 (step S115). Here, the method itself for determining the direction of the driver's line of sight is arbitrary. For example, a comprehensive line-of-sight direction can be obtained by superimposing the driver's face direction and the line-of-sight direction relative to the face direction.

  As for the orientation of the face, for example, as described in Japanese Patent Application Laid-Open No. 2006-65673, the face image is processed by a Sobel filter or the like, and the vertical and horizontal edges of the face (both sides of the face and the face) The position of the eyebrow / mouth, etc.) is detected, and on the other hand, the face image is binarized to obtain the center of gravity in the vertical and horizontal directions, and the position of the center of gravity with respect to the edge is obtained to obtain the face orientation. Further, an eye image is extracted from the face image, and the direction of the line of sight is obtained from the amount of deviation in the vertical and horizontal directions between the black eye portion and the center of the eye.

  The CPU 10 calculates a line-of-sight angle θ formed by the detected line-of-sight direction and the vehicle traveling direction and stores it in the RAM 20. Then, the CPU 10 reads the line-of-sight allowable limit angle θt from the ROM 30 and compares the absolute value of the line-of-sight angle θ with the line-of-sight allowable limit angle θt. The CPU 10 determines whether or not the driver is facing the traveling direction by determining whether or not the absolute value of the line-of-sight angle θ exceeds the line-of-sight allowable limit angle θt (step S120).

  If the driver is facing the direction of travel (step S120; YES), the CPU 10 determines that the driver is not looking aside and turns off the aside driving flag FW indicating that the driver is looking aside. This flag is stored in the RAM 20 (step S125). Then, the timer TA and the timer TB are cleared and the measurement is repeated from the start (step 110).

When the driver is not facing the traveling direction (step S120: NO), the CPU 10 reads the viewing angle θ from the RAM 20, and reads the right door mirror angle θsr, the left door mirror angle θsl, and the door mirror allowable limit angle θst from the ROM 30. And CPU10 discriminate | determines whether the driver | operator is facing the door mirror direction by discriminate | determining whether any one of the following numerical formula 1 or numerical formula 2 is materialized (step S130).
| Θ−θsr | ≦ θst (Equation 1)
| Θ−θsl | ≦ θst (Equation 2)

  When the driver's line of sight does not face the door mirror (step S130; NO), the CPU 10 clears the mirror gaze timer TB and restarts (step S135). If the driver's line of sight is facing the door mirror (step S130; YES), the armpit timer TA is cleared and restarted (step S140). When the armpit timer TA is longer than the mirror gaze timer TB, the timer TA may be cleared and restarted (step S140).

  The CPU 10 refers to the state of the vehicle stored in the RAM 20 and the relative speed of the preceding vehicle in the braking control process described later, reads the door mirror gazing allowable limit time Tst corresponding to the state from the ROM 30, and measures the mirror gazing timer TB. It is determined whether or not the elapsed time exceeds the door mirror gaze allowable limit time Tst (step S145). If the time measured by the door mirror gaze timer TB exceeds the door mirror gaze allowable limit time Tst (step S145: YES), the CPU 10 determines that the driver is looking aside (step S155).

  If the measurement time of the door mirror gaze timer TB does not exceed the door mirror gaze allowable limit time Tst (step S145; NO), the CPU 10 sets the side look allowable limit time Tt corresponding to the vehicle state and the relative speed of the preceding vehicle to the ROM 30. From the above, it is determined whether or not the time measured by the sidewatch timer TA exceeds the sidewatch allowable limit time Tt (step S150). If the time measured by the armpit timer TA exceeds the armpit look allowable limit time Tt (step S150; YES), the CPU 10 determines that the armpit operation is in operation (step S155). The CPU 10 turns on the armpit driving flag FW and stores it in the RAM 20. Then, the timer TA and the timer TB are cleared and the measurement is repeated from the start (step 110).

  If the time measured by the armpit timer TA does not exceed the armpit allowable time limit Tt (step S150; NO), the timer TA and TB are continuously counted, and the eye gaze direction detection (step S115) is repeated.

  Thus, when the line of sight continues beyond the advancing direction of the vehicle for at least a sideward allowable limit time Tt, or when the line of sight continues at the door mirror gazing allowable limit time Tst for a continuous direction of the door mirror, The flag FW is set on. When the line of sight turns in the traveling direction, the side-view driving flag FW is set off.

  FIG. 6 is a flowchart illustrating an example of the braking control process. In the braking control process (step S200), when the distance to the obstacle in the vehicle traveling direction becomes smaller than a predetermined distance, the vehicle is braked and the distance to the obstacle (obstacle distance) is set to the reference distance or more. It is a process for maintaining. When the driver performs a look aside while the auto-cruise function is operating, the reference distance is set longer than when the driver does not perform a look aside.

  First, the CPU 10 acquires the own vehicle state information via the vehicle speed sensor 110 and a vehicle control device (not shown), and stores the acquired value in the RAM 20 (step S205). The own vehicle state information includes information on the vehicle speed Vc (km / h) and other vehicle acceleration, yaw rate, steering angle, weather, road surface condition, and the like.

  Next, the CPU 10 reads the vehicle speed Vc from the RAM 20 and determines whether or not the vehicle is stopped by determining whether or not the vehicle speed Vc is 0 (km / h) (step S210). ). When the vehicle is stopped (step S210: YES), the CPU 10 repeats from the acquisition of own vehicle state information (step S205).

  When the vehicle is not stopped (step S210: NO), the CPU 10 checks whether or not the follow-up ACC operation flag FA is on, and determines whether or not the auto cruise control is operating (step S215). . If the auto cruise control is not operating (step S215: NO), the CPU 10 repeats from the acquisition of the own vehicle state information (step S205).

  If the auto cruise control is operating (step S215; YES), the CPU 10 inputs the distance (m) from the inter-vehicle distance sensor 130 to the obstacle ahead and stores it in the RAM 20 as the obstacle distance (step S220). . Then, a reference distance L to be maintained as a distance to the obstacle ahead in the traveling direction is set according to at least the vehicle speed Vc, and stored in the RAM 20 (step S225). The reference distance L may be set according to a condition that combines not only the vehicle speed but also the vehicle acceleration, the yaw rate, the steering angle, and the relative speed of the obstacle in the traveling direction of the vehicle with respect to the vehicle.

  Subsequently, the CPU 10 reads the armpit driving flag FW from the RAM 20, checks whether the FW is on, and determines whether the driver is performing the armpit driving (step S230). If the driver is performing a look-aside operation (step S230; YES), the CPU 10 reads the reference distance L from the RAM 20, and adds an additional distance Ls in the case of a look-ahead operation to L. Then, the CPU 10 stores the value after addition in the RAM 20 as the reference distance L (step S235). In addition to the vehicle speed, the additional distance in the case of driving aside is set according to the conditions that combine the vehicle's acceleration, yaw rate, steering angle, and the relative speed of the obstacle in the traveling direction of the vehicle with respect to the vehicle. Also good.

  When the driver is not performing the aside driving (step S230: NO) or after step S235, the CPU 10 reads the obstacle distance and the reference distance L from the RAM 20, and compares the obstacle distance with the reference distance L. . The CPU 10 determines whether or not the obstacle distance is greater than or equal to the reference distance L (step S240). Here, if the obstacle distance is equal to or greater than the reference distance L, it is expected that the vehicle can be stopped before the obstacle because a sufficient obstacle distance is maintained.

  When the obstacle distance is not greater than or equal to the reference distance L (step S240: NO), the CPU 10 operates the braking device 150 by transmitting an operation signal to the braking control unit 40 (step S255). Further, the CPU 10 turns on the braking device operation flag FB to stop the auto cruise function. CPU10 repeats from own vehicle state information acquisition (step S205).

  When the obstacle distance is not less than the reference distance L (step S240: YES), the CPU 10 stops the braking device 150 by transmitting a stop signal to the braking control unit 40 (step S245). Then, the CPU 10 turns off the braking device operation flag FB and operates the auto-cruise function (step S250). The vehicle travels following the preceding vehicle within the set speed by the operation of the auto-cruise function. And CPU10 repeats from own vehicle state information acquisition (step S205).

  By repeating the above processing, the speed control device 1 increases the reference distance L to be maintained as the distance to the obstacle in the vehicle traveling direction when it is determined to be a sideward driving, compared to the case where it is not a sideward driving, It works to increase the obstacle distance.

  FIG. 7 is a flowchart illustrating an example of the alarm device operation process. In the alarm device operation process (step S300), when the distance to the obstacle in the vehicle traveling direction becomes shorter than the reference distance L, an alarm of a different level is given to the alarm device 140 depending on whether or not the driver is driving aside. This is a process to be generated.

  The CPU 10 receives the vehicle speed Vc from the vehicle speed sensor 110 or reads the vehicle speed Vc stored in the braking control process from the RAM 20 and checks whether Vc is 0 (km / h), and the vehicle is stopped. It is determined whether or not (step S305). When the vehicle is stopped (step S305; YES), the CPU 10 instructs the alarm control unit 50 to stop the alarm (step S310). And it repeats from vehicle speed determination (step S305).

  When the vehicle is not stopped (step S305; NO), the CPU 10 reads the obstacle distance and the reference distance L from the RAM 20, and determines whether or not the obstacle distance is greater than or equal to the reference distance L (step S315). If the obstacle distance is greater than or equal to the reference distance L (step S315; YES), the CPU 10 instructs the alarm control unit 50 to stop the alarm (step S310). And it repeats from vehicle speed determination (step S305).

  If the obstacle distance is not equal to or greater than the reference distance L (step S315; NO), the CPU 10 reads the armpit driving flag FW from the RAM 20, checks whether the FW is on or off, and determines whether the driver is performing the armpit driving. Is determined (step S320). If the driver is driving aside (step S320; YES), the CPU 10 notifies the warning control unit 50 of the strong warning, thereby causing the warning device 140 to generate a strong warning (step S330).

  If the driver is not performing an aside look operation (step S320; NO), the CPU 10 notifies the alarm control unit 50 of a weak alarm, thereby causing the alarm device 140 to generate a weak alarm (step S335). And it repeats from vehicle speed determination (step S305).

  By repeating the above processing, the CPU 10 generates a strong warning when the obstacle distance is smaller than the reference distance L and the driver is driving aside, while the obstacle distance is smaller than the reference distance L and the driving is performed. When a person is not driving aside, a weak warning is generated. When the obstacle distance is equal to or greater than the reference distance L, no alarm is generated. The reference distance L is set longer by the addition distance Ls by the braking control process when it is determined to be the side-by-side operation by the side-by-side driving determination process.

  By implementing the vehicle speed control device according to the above-described embodiment, it is possible to determine whether or not the driver is driving aside from the driver's line-of-sight direction and the traveling direction of the vehicle. And the speed control apparatus 1 maintains the distance from a vehicle to an obstruction longer when the driver is performing the look-ahead driving than when not performing the look-ahead driving. Therefore, even when the driver is driving aside, a safer inter-vehicle distance according to the driver's condition can be maintained. In addition, when the distance to the obstacle is not equal to or greater than the predetermined distance and the driver is not performing the look aside, the alarm level is lower than when the driver is performing the look aside. Therefore, it is possible to eliminate the feeling of humility for the driver.

  In the braking control process, when it is determined that the driver is looking aside and the reference distance L is set to be long, the reference distance L that is long for the driver can be maintained until the auto-cruise operation is reset.

[Embodiment 2]
Next, a speed control apparatus according to Embodiment 2 of the present invention will be described. The configuration of the speed control device 1 according to the second embodiment is the same as that of the speed control device 1 according to the first embodiment shown in FIG. However, in the second embodiment, the speed control device 1 uses accelerator control for braking control. Therefore, the accelerator control unit 60 may be configured to be able to simultaneously perform a gear shift operation of the transmission. Further, the aside operation determination process and the alarm device operation process are the same as those in the first embodiment.

  FIG. 8 is a flowchart illustrating an example of a braking control process of the speed control device 1 according to the second embodiment. In FIG. 8, the operation of each step except steps S220a, S245a, and S255a is the same as the operation of FIG. That is, Steps S205 to S215, Steps S225 to S240, and Step S250 are the same as the operation of FIG.

  In FIG. 8, if the auto cruise control is in operation (step S215; YES), the CPU 10 determines the distance from the inter-vehicle distance sensor 130 to the front obstacle and / or the relative speed of the front obstacle with the own vehicle. It is input and stored in the RAM 20 as the obstacle distance and relative speed (step S220a). Then, a reference distance L to be maintained as a distance to the obstacle ahead in the traveling direction is set according to at least the vehicle speed Vc, and stored in the RAM 20 (step S225). The reference distance L may be set corresponding to the vehicle speed and the relative speed of the obstacle.

  After resetting the reference distance in the case of aside look driving, when the obstacle distance is not equal to or greater than the reference distance L (step S240; NO), the CPU 10 transmits an operation signal for closing the throttle opening to the accelerator control unit 60. The accelerator device 160 is operated to apply the engine brake (step S255a). Further, the CPU 10 may transmit a shift down command for the transmission to increase the reduction ratio of the transmission and apply the braking of the engine brake.

  When the obstacle distance is equal to or greater than the reference distance L (step S240: YES), the CPU 10 stops the braking (engine braking) of the accelerator device 160 by releasing the operation signal for closing the throttle opening to the accelerator control unit 60. (Step S245a). Further, the CPU 10 releases the transmission downshift command. Then, the CPU 10 turns off the braking device operation flag FB and operates the auto-cruise function (step S250). The vehicle travels following the preceding vehicle within the set speed by the operation of the auto-cruise function. And CPU10 repeats from own vehicle state information acquisition (step S205).

  In the second embodiment, when the obstacle distance is not equal to or greater than the reference distance L, the accelerator device 160 and / or the transmission is shifted to decelerate, so that the following ACC operation becomes smoother and the passenger does not feel uncomfortable. . Note that the braking device 150 and the accelerator device 160 may be used in combination with the reference distance L in two stages.

  Note that the side-by-side driving determination process (S100) is performed not only when the driver is looking at the door mirror but also when the driver is looking at the room mirror (interior rear view mirror) within a predetermined time. For example, a configuration that does not discriminate from the side-view driving may be used.

  Also, the aside driving determination process (S100) may be configured to determine that the driver is looking aside when the vehicle is turning and the line of sight is not facing in the forward turning direction. Whether the vehicle is turning can be determined by detecting the yaw rate or the steering angle. Information about the curve ahead can be obtained from a car navigation system or the like.

  Furthermore, the speed control device 1 acquires the driver's state from a biosensor, an indoor camera, and the like, and the distance to the obstacle even when the driver lacks concentration or sleeps. It is good also as a structure which takes large.

[Embodiment 3]
Next, a speed control apparatus according to Embodiment 3 of the present invention will be described. The configuration of the speed control device 1 according to the second embodiment is the same as that of the speed control device 1 according to the first embodiment shown in FIG. In the third embodiment, the speed control device 1 detects that the accelerator pedal 170 is operated, and changes the setting of the reference distance after the side-by-side driving determination. The armpit driving determination process and the alarm device operation process are the same as those in the first embodiment.

  In the third embodiment, after the reference distance is once set to the second reference distance (reference distance in the case of the aside operation), the second reference distance is set as the reference distance L regardless of the result of the aside operation determination process. To do. Further, if it is detected that the accelerator pedal 170 is operated after the second reference distance is set, the reference distance is returned to the first reference distance and the auto-cruise control is continued unless the driver is looking aside.

  FIG. 9 is a flowchart for explaining the operation of the third embodiment. In FIG. 9, the operation of each step excluding steps S230b to S240 is the same as the operation of FIG. That is, steps S205 to S225 and steps S240 to S255 are the same as the operation of FIG.

  As shown in FIG. 9, after setting the reference distance (step S225), if it is determined that the driver is looking aside (step S230b; YES), the reference distance is reset as in the first embodiment (FIG. 6). This is performed (step S235b). On the other hand, if it is determined that the operation is not a side look driving (step S230b; NO), it is determined whether or not the previous reference distance has been reset (whether or not the reference distance of the previous loop is the second reference distance) ( Step S231b). If the previous reference distance has not been reset (step S231b; NO), the reference distance is not reset (step S235b). If the previous reference distance has been reset (step S231b; YES), it is determined whether or not the reference distance reset has been canceled (step S232b).

  In the third embodiment, when the accelerator pedal operation detecting device 180 shown in FIG. 1 detects that the accelerator pedal 170 is operated, it is determined that the reference distance resetting is released. Once the reference distance is reset, if the accelerator pedal 170 is not operated, it is determined that the reset of the reference distance has not been released. If it is determined that the reference distance resetting is not canceled (step S232b; NO), the reference distance is reset (the reference distance is set to the second reference distance) (step S235b). When the resetting of the reference distance is canceled (step S232b; YES), the resetting of the reference distance (step S235b) is not performed, and it is determined whether the obstacle distance is equal to or greater than the reference distance (step S240).

  Note that it may be determined that the resetting of the reference distance has been canceled by resetting (stopping and restarting) the auto cruise control.

  As described above, in the third embodiment, after the reference distance is once set to the second reference distance, until the predetermined release condition is satisfied, regardless of the result of the armpit driving determination process, the first distance is set. Two reference distances are set as the reference distance. Furthermore, even after the reference distance is set to the second reference distance, for example, when an operation (release condition) of the accelerator pedal 170 is detected, the setting of the reference distance to the second reference distance is canceled. When the driver is not looking aside, the reference distance is set as the first reference distance.

  In the speed control device 1 of the present invention, the inter-vehicle distance from the preceding vehicle is set large where the driver does not recognize while the driver is looking aside. Thereafter, when it is determined that the driver is not looking aside, if the inter-vehicle distance is set to the first reference distance (a reference distance when the driver is not looking aside), the distance to the preceding vehicle is gradually reduced. Since the driver who has returned to the normal driving state from the side-by-side state does not recognize that the inter-vehicle distance has increased, but only recognizes that the inter-vehicle distance has decreased, the driver may feel anxious.

  In the operation of the speed control device 1 according to the third embodiment, after the reference distance is once set to the second reference distance, regardless of whether the driver is driving aside or not, the reference distance reset release condition is The second reference distance is set as the reference distance until it is established. Therefore, when the driver returns to the normal driving state from the looking-aside state, the distance from the preceding vehicle is not automatically reduced, and the driver can be prevented from feeling uneasy.

  Further, in the third embodiment, when it is detected that the accelerator pedal 170 is operated even after the reference distance is once set to the second reference distance, the reference distance is reset (to the second reference distance). (To be set as the first reference distance as the reference distance). In that case, it can be read by operating the accelerator pedal 170 that the driver wants to reduce the distance from the preceding vehicle. Even if the distance to the preceding vehicle is reduced by changing to the first reference distance, the driver does not feel uneasy.

  Further, when the driver returns from the looking-aside state to the normal driving state, the reference distance may be returned from the second reference distance to the first reference distance. In this case, the driver may be informed of “returning to the normal driving state from the side-viewing state” or “reducing the reference distance (reset to the first reference distance) since returning to the normal driving state”. preferable. By these notifications, the driver can recognize the reason why the distance from the preceding vehicle is shortened, so that the driver can be prevented from feeling uneasy.

  Note that the condition other than the detection of the operation of the accelerator pedal 170 may be used as a condition for canceling the setting of the reference distance to the second reference distance. For example, when a release switch is installed in the vehicle and this switch is operated, setting the reference distance to the second reference distance may be released.

It is a block diagram of the speed control apparatus which concerns on embodiment of this invention. It is a figure explaining follow auto cruise control operation. It is a figure for demonstrating a gaze angle, a right door mirror angle, and a left door mirror angle. It is a flowchart of the speed control process of the speed control apparatus which concerns on embodiment of this invention. It is a flowchart which shows an example of the aside driving | operation discrimination | determination process which concerns on embodiment of this invention. It is a flowchart which shows an example of the brake control process which concerns on Embodiment 1 of this invention. It is a flowchart which shows an example of the alarm device action | operation process which concerns on embodiment of this invention. It is a flowchart which shows an example of the braking control process which concerns on Embodiment 2 of this invention. It is a flowchart which shows an example of the braking control process which concerns on Embodiment 3 of this invention.

Explanation of symbols

1 Speed control device 10 CPU (distance setting means, control means, side-view discrimination means, line-of-sight direction detection means)
20 RAM
30 ROM
40 Braking control unit (control means)
60 Accelerator control unit (control means)
100 control unit (distance setting means, control means, side-arm discrimination means, line-of-sight direction detection means)
110 Vehicle speed sensor (vehicle speed detection means)
120 Indoor camera (imaging means)
130 Inter-vehicle distance sensor (distance measuring means)
150 Braking device (braking means)
160 Accelerator (braking means, acceleration means)
170 Accelerator pedal (acceleration adjustment means)
180 Accelerator pedal operation detection device

Claims (8)

Vehicle speed detection means for detecting the speed of the vehicle;
Distance measuring means for measuring a preceding vehicle distance to a preceding vehicle in the traveling direction of the vehicle;
Distance setting means for setting a reference distance to the preceding vehicle to be held based on the speed of the vehicle;
The vehicle is made to follow the preceding vehicle, and the braking means and / or acceleration of the vehicle is made so that the preceding vehicle distance measured by the distance measuring means is larger than the reference distance set by the distance setting means. Control means for operating the means;
A side-by-side determination means for determining whether the driver of the vehicle is performing a side-by-side driving;
With
The distance setting means is the first when the driver determines that the driver is not looking aside when the driver determines that the driver is looking aside. Set a second reference distance greater than the reference distance;
A speed control device characterized by that. The speed control device includes an imaging unit that captures an image of the driver's face area;
Gaze direction detecting means for detecting the gaze direction of the driver from the image of the face area;
With
The side look determination means determines that the driver is looking aside when the line of sight of the driver detected by the line of sight detection means does not coincide with the traveling direction of the vehicle.
The speed control apparatus according to claim 1. The side look determination means determines that the driver's line of sight detected by the line of sight detection means does not coincide with the direction of travel of the vehicle for a predetermined time,
The speed control apparatus according to claim 2.   The aside look determining means changes a predetermined time for determining the look aside driving based on any combination of the vehicle speed, acceleration, yaw rate, steering angle, and relative speed of the obstacle with respect to the vehicle. The speed control device according to claim 3.   The aside look determining means determines that the driver is looking aside when the driver's line of sight direction detected by the line-of-sight direction detecting means faces the direction of the indoor rear view mirror or the outdoor rear view mirror of the vehicle within a predetermined time. The speed control device according to claim 2, wherein the speed control device is not.   The distance setting means sets the reference distance based on any combination of speed, acceleration, yaw rate, steering angle and relative speed of the obstacle with respect to the vehicle. The speed control apparatus according to 1.   The distance setting means sets the second reference distance as the reference distance once the reference distance is set to the second reference distance, regardless of the determination result of the look-ahead determination means. The speed control apparatus according to any one of claims 1 to 6, wherein the speed control apparatus is characterized in that:   The distance setting means sets the second reference distance as the reference distance until an operation of the acceleration adjusting means of the vehicle is detected after the reference distance is once set to the second reference distance. 8. The speed control apparatus according to claim 7, wherein

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