JP4771602B2 - Auto cruise equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid continuous interruption and unnecessary slowdown in constant vehicle-to- vehicle distance travel. SOLUTION: This automatic cruising device is provided with a vehicle-to-vehicle distance detecting means for determining a preceding vehicle which an own vehicle should follow and detecting the vehicle-to-vehicle distance to the preceding vehicle; a vehicle-to-vehicle distance setting means for setting beforehand the vehicle-to-vehicle distance to the preceding vehicle; and a vehicle-to-vehicle control means for controlling the vehicle speed so that the vehicle-to-vehicle distance to the preceding vehicle is maintained to the set vehicle-to-vehicle distance. The automatic cruising device is further provided with a vehicle-to-vehicle distance decrease determining means for determining the decease of the current vehicle-to-vehicle distance to the set vehicle-to-vehicle distance or less, and a target vehicle-to-vehicle distance setting means for setting the current vehicle-to-vehicle distance in response to the determination of the decrease of the vehicle-to-vehicle distance. If the target vehicle-to-vehicle distance is set, the vehicle-to-vehicle control means changes vehicle speed control for maintaining the vehicle-to-vehicle distance to the set vehicle-to-vehicle distance, over to vehicle-speed control for maintaining to the target vehicle-to-vehicle distance. The vehicle-to-vehicle control means then controls the vehicle speed to return the target vehicle-to-vehicle distance stepwise to the set vehicle-to-vehicle distance.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention sets the inter-vehicle distance reduced due to an interruption by another vehicle or a change in the lane of the own vehicle to the set inter-vehicle distance during cruise control with an inter-vehicle control function for controlling the inter-vehicle distance with the preceding vehicle. The present invention relates to a system capable of adjusting the return time.
[0002]
[Prior art]
Recently, a cruise control system with an inter-vehicle control function (hereinafter referred to as an ACC system) has been proposed and put into practical use. The ACC system uses a radar, a camera, etc., and if a preceding vehicle is detected, it performs “fixed distance travel” to maintain the set inter-vehicle distance, and if no preceding vehicle is detected, the set vehicle speed Carry out "constant vehicle speed driving" to maintain the above. The travel mode in which the inter-vehicle distance and the vehicle speed are adjusted according to the presence or absence of the preceding vehicle in this manner is hereinafter referred to as “inter-vehicle control mode”.
[0003]
Japanese Patent Application Laid-Open No. 11-42957 discloses an example of a cruise control system that realizes an inter-vehicle control mode. According to this system, the inter-vehicle distance can be set by switching in three stages, and the driver can display at a glance which inter-vehicle distance is currently set.
[0004]
Thus, in the conventional ACC system, when a preceding vehicle is detected, traveling between fixed vehicles based on the set inter-vehicle distance is performed. In such fixed inter-vehicle travel, if the inter-vehicle distance to the preceding vehicle temporarily decreases due to an interruption by another vehicle or a change in the lane of the host vehicle, deceleration control is performed so as to quickly return to the set inter-vehicle distance. Executed.
[0005]
FIG. 22 is a diagram for explaining such a situation. In the figure, numbers {circle around (1)}, {circle around (2)} assigned to the respective vehicles are numbers for identifying the respective vehicles. In the own vehicle 500, it is assumed that the set vehicle speed is set to 100 km / h and the set inter-vehicle distance is set to “short”. In this example, it is assumed that the “short” of the set inter-vehicle distance corresponds to about 42.5 m.
[0006]
First, as shown in FIG. 22A, the own vehicle 500 detects the first other vehicle 510 as a preceding vehicle, and therefore the own vehicle 500 has an inter-vehicle distance to the first other vehicle 510. A fixed inter-vehicle travel is performed so as to maintain the set inter-vehicle distance of 42.5 m. FIG. 22B shows a situation in which the second other vehicle 520 has changed lanes and has interrupted between the host vehicle 500 and the first other vehicle 510. The own vehicle 500 detects the second other vehicle 520 and starts deceleration control so that the inter-vehicle distance with respect to the second other vehicle 520 becomes the set inter-vehicle distance. As a result, as shown in FIG. 22C, the inter-vehicle distance with respect to the second other vehicle 520 becomes the set inter-vehicle distance of 42.5 m. The own vehicle 500 shifts to follow-up traveling to the second other vehicle 520 so that the inter-vehicle distance to the second other vehicle 520 is maintained at the set inter-vehicle distance of 42.5 m. FIG. 22D again shows a situation where the third other vehicle 530 has interrupted between the host vehicle 500 and the second other vehicle 520. The own vehicle 500 starts the deceleration control so that the inter-vehicle distance from the third other vehicle 530 becomes the set inter-vehicle distance. As a result, as shown in FIG. 22E, the inter-vehicle distance with respect to the third other vehicle 530 is the set inter-vehicle distance of 42.5 m. The own vehicle 500 shifts to follow-up traveling to the third other vehicle 520 so that the inter-vehicle distance with respect to the third other vehicle 530 is maintained at the set inter-vehicle distance of 42.5 m.
[0007]
[Problems to be solved by the invention]
Thus, even if the shortest set inter-vehicle distance (for example, 42.5 m) is selected in the ACC system, the set inter-vehicle distance is normally set longer than the inter-vehicle distance between surrounding vehicles. There is a high possibility of being interrupted by a car. In particular, in a situation where the road is relatively congested, there is a possibility that a situation in which the road is continuously interrupted in a short time may occur.
[0008]
Also, if the vehicle changes its lane immediately behind another vehicle traveling on the overtaking lane while following a preceding vehicle with a vehicle speed slower than the set vehicle speed, the ACC system of the own vehicle Then, deceleration control is started in an attempt to secure the inter-vehicle distance. When the speed of the other vehicle traveling on the adjacent lane is faster than the speed of the own vehicle, when such deceleration control is executed, the inter-vehicle distance from the other vehicle increases as a result. This can disrupt the flow of the vehicle in the overtaking lane.
[0009]
Accordingly, there is a need for an ACC system that automatically adjusts the inter-vehicle distance in accordance with the traffic conditions of surrounding roads and avoids continuous interruptions and unnecessary deceleration during constant-vehicle travel using the ACC system.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the invention of claim 1 An inter-vehicle distance detecting means for determining a preceding vehicle to be followed by the host vehicle and detecting an inter-vehicle distance with respect to the preceding vehicle, an inter-vehicle distance setting means for presetting an inter-vehicle distance with respect to the preceding vehicle, and a preceding vehicle detected by the inter-vehicle distance detecting means In the auto-cruise device comprising the inter-vehicle control means for controlling the vehicle speed so that the inter-vehicle distance is maintained at the inter-vehicle distance set by the inter-vehicle distance setting means, the inter-vehicle distance detected by the inter-vehicle distance detection means is the traveling direction of the own vehicle In response to the interruption of the other vehicle, the vehicle distance reduction determining means for determining that the vehicle distance has been reduced to the vehicle distance or less set by the vehicle distance setting means, and the vehicle distance reduction determining means responding to the reduction of the vehicle distance being determined. The target inter-vehicle distance setting means for setting the inter-vehicle distance detected by the inter-vehicle distance detection means as the target inter-vehicle distance, and the surroundings of the own vehicle By dividing the return amount corresponding to the difference between the target inter-vehicle distance and the set inter-vehicle distance by the traffic volume setting means for setting the traffic volume by the return period set according to the traffic volume set by the traffic volume setting means, the target A return amount calculating means for calculating a return amount per unit time of the inter-vehicle distance, and the inter-vehicle control means sets the inter-vehicle distance with respect to the preceding vehicle if the target inter-vehicle distance is set by the target inter-vehicle distance setting means. While switching from the control of the vehicle speed maintained at the inter-vehicle distance to the control of the vehicle speed maintained at the target inter-vehicle distance, the set target inter-vehicle distance is gradually returned to the set inter-vehicle distance based on the return amount per unit time. Control the vehicle speed The configuration is taken.
[0011]
According to the invention of claim 1, Due to the interruption of the other vehicle in the direction of travel of your vehicle, When the inter-vehicle distance with respect to the preceding vehicle decreases, the current inter-vehicle distance is automatically set as the target inter-vehicle distance, so that continuous interruptions by other vehicles can be avoided. further, The vehicle speed is controlled so that the set target inter-vehicle distance is gradually returned to the set inter-vehicle distance based on the return amount per unit time calculated based on the traffic volume around the host vehicle. It is possible to adjust the time for returning to fixed vehicle travel, avoid unnecessary deceleration control, and return to fixed vehicle travel without causing the driver to feel uncomfortable. .
[0012]
The invention of claim 2 is the auto-cruise device of the invention of claim 1, wherein the inter-vehicle distance control means is The return distance per unit time calculated by the return amount calculation means is added to the target inter-vehicle distance in the previous cycle to calculate the target inter-vehicle distance in the current cycle, and the calculated target inter-vehicle distance in the current cycle is obtained. Control the vehicle speed The configuration is taken.
[0013]
According to the invention of claim 2, Since the target inter-vehicle distance is updated with the most recent return amount calculated per unit time, it is possible to return to the fixed inter-vehicle travel without causing the driver to feel uncomfortable according to the latest traffic state. .
[0014]
The invention of claim 3 is the auto cruise device of the invention of claim 1 or claim 2, The return period is set longer as the traffic volume set by the traffic volume setting means increases. The configuration is taken.
[0015]
According to the invention of claim 3, Since the return period is set longer as the traffic volume increases, the return to the fixed inter-vehicle driving is performed slowly in a situation where the traffic volume is high, thus avoiding continuous interruptions. .
[0016]
The invention of claim 4 3. The auto cruise device according to claim 1 or 2, wherein the traffic volume setting means includes a switch operable by a user to set the traffic volume. The configuration is taken.
[0017]
According to the invention of claim 4, Since the traffic volume can be set at the user's discretion, it is possible to eliminate the uncomfortable feeling during driving by setting the return period as intended by the user. .
[0038]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an object detection device according to an embodiment of the present invention.
[0039]
The object detection device 1 includes a light transmission unit 2, a light transmission scanning unit 3, a light receiving unit 4, and a distance measurement processing unit 5, and detects the distance, direction, and relative speed of an object in front of the host vehicle. The light transmission unit 1 includes a laser diode 10, a light transmission lens 11 that condenses the laser light transmitted from the laser diode 10, and a laser diode drive circuit 12 that drives the laser diode 10. The light transmission scanning unit 3 reflects the laser output from the laser diode 10 through the light transmission lens 11 and irradiates light forward, and the light transmission mirror 13 reciprocates about the vertical axis. A motor 15 to be rotated and a motor drive circuit 16 for controlling the drive of the motor 15 are provided. The light receiving unit 4 includes a light receiving lens 17, a photodiode 18 that receives a reflected wave converged by the light receiving lens 17 and converts it into an electric signal, and a light receiving amplifier circuit 19 that amplifies an output signal of the photodiode 18.
[0040]
The distance measurement processing unit 5 includes a control circuit 24 that controls the laser diode drive circuit 12 and the motor drive circuit 16, a communication circuit 26 that communicates with the ACC system 30, and a time from laser light transmission to light reception. A counter circuit 27 that counts and a central processing unit (CPU) 28 that calculates a distance to the object, a direction of the object, and a relative speed are provided.
[0041]
The operation of the object detection device 1 will be described with reference to FIG. The control circuit 24 issues a light emission command to the LD drive circuit 12 to cause the laser diode 10 to emit light in pulses (the wavelength of the laser light is 870 nm, for example). At the same time, the control circuit 24 sends the light emission timing to the counter circuit 27 and starts the counter. The laser light sent out by the laser diode 10 is condensed by the light sending lens 11 and sent to the light sending mirror 13. The light transmission mirror 13 is driven left and right by the motor 15, and thus the laser light is scanned left and right by the light transmission mirror 13. The angle of the light transmission mirror 13 when the laser light is transmitted by the light transmission mirror 13 is sent to the CPU 28 through the control circuit 24.
[0042]
The emitted laser light is reflected by a reflector of an object in front (in the case of a preceding vehicle, the reflector is embedded in the tail lamp). The light receiving lens 17 receives the reflected laser light, and the received light is converted into an electric signal by the photodiode 18 and further amplified by the light receiving amplifier circuit 19. The amplified signal is sent to the counter circuit 27, whereby the counter that has started to rotate at the light transmission timing is stopped. The counter value is sent to the CPU. The CPU 28 calculates the direction of the front object and the distance to the object from the angle of the light transmission mirror and the counter value. Specifically, the distance to the object is calculated by the following equation. Thus, the position of the object is specified.
[0043]
[Expression 1]
Distance = speed of light (approx. 300,000 kilometers / second) x elapsed time from light emission to light reception / 2
[0044]
FIG. 2 shows a scanning range of the laser light emitted from the object detection device 1 according to the embodiment of the present invention. As shown in the figure, the object detection device 1 is preferably provided at the center of the front grille of the own vehicle, which is less susceptible to the effects of rolling up of the preceding vehicle and dirt and can detect left and right vehicles equally. The laser beam transmitted from the object detection device 1 is a fan-shaped beam that is narrow in the left-right direction and has a size of 58 mrad in the vertical direction (milliradian, 58 mrad corresponds to about 3.3 degrees), and has a predetermined period. (For example, 0.1 seconds), the vehicle reciprocates 280 mrad (about 16 degrees) in the left-right direction, and scans the front of the vehicle.
[0045]
FIG. 3 is a flowchart illustrating a method of detecting an object and calculating the position and relative speed of the object, which is executed by the object detection apparatus. Object detection is repeatedly executed in a predetermined cycle (for example, 100 milliseconds).
[0046]
In step 101, all the reflectors in the detection area are detected and stored in the reflector memory, and are the same as the reflector data existing within a predetermined range (for example, within ± 1.5 m in both the left and right directions and the front and rear direction). A temporary number is assigned (102). Next, the reflector data to which the same temporary number is assigned is used as one target, and for each target, the average value of the distance of the reflector data, the average value of the left and right positions, and the left and right widths (two pieces located at the left and right ends) The distance between the reflection data is calculated and stored in the target memory (103).
[0047]
In step 104, the moving object target is taken over. Specifically, the moving object target is read from the target memory of the previous cycle, and the position of the moving object target in the current cycle is predicted from the position and the relative speed. Of the targets detected in the current cycle, the target closest to the predicted position is determined to be the same as the previously detected moving object target, and the relative speed is calculated based on the difference between the previous position and the current position. To do.
[0048]
Next, in step 105, takeover of the stationary object target is performed. Specifically, the stationary object target is read from the target memory of the previous cycle, and the position of the stationary object target in the current cycle is predicted from the position and the relative speed. Among the targets detected this time, the target closest to the predicted position is determined to be the same as the previously detected stationary object target, and the relative speed is calculated based on the difference between the previous position and the current position.
[0049]
In step 106, the new target is taken over. Specifically, a new target is read from the target memory of the previous cycle, and among the targets detected this time, the target closest to the position of the new target detected last time is made the same. The relative speed is calculated from the new target detected last time and the target detected this time and determined to be the same.
[0050]
In step 107, when there is no target to be taken over from the previous cycle in the target detected this time (that is, the target was detected in the previous cycle but the corresponding target was not detected in the current cycle), Interpolation processing is performed on the detected target. The interpolation process can be performed by predicting the target position of the current cycle based on the past relative speed.
[0051]
On the other hand, in step 108, among the targets detected this time, a new target number is assigned to a target that does not exist in the previous cycle (that is, a target newly detected in the current cycle).
[0052]
In step 109, the host vehicle speed is compared with the relative speed for each target, and a relative speed close to a negative value of the host vehicle speed (for example, if the host vehicle speed is 90 km / h, the negative value is -90 km / h). The target having the stationary object is set as the stationary object target, and the target having the relative speed away from the negative value of the own vehicle speed is set as the moving object target (attribute determination).
[0053]
Thus, the object position, relative velocity, and attribute obtained by the object detection device 1 for each object within the detection area of the laser diode are transferred to the ACC system 30.
[0054]
Object detection can be realized by any other method. For example, a millimeter wave radar can be used instead of the laser radar. Alternatively, the position and relative velocity of the object can be obtained using an imaging device such as a CCD camera. Alternatively, an object in front of the host vehicle can be recognized by combining the radar device and the imaging device.
[0055]
FIG. 4 is a functional block diagram of the ACC system 30 shown in FIG. 1 according to one embodiment of the present invention. The ACC system 30 is a system that performs constant vehicle speed travel that maintains a set vehicle speed when a preceding vehicle is not detected, and performs constant vehicle travel that maintains a set inter-vehicle distance when a preceding vehicle is detected. The ACC system 30 actually provides a central processing unit (CPU), a read-only memory (ROM) for storing control programs and control data, and a calculation work area for the CPU, and can temporarily store various data. This is realized by an electronic control unit (ECU) including a random access memory (RAM).
[0056]
The input of the ACC system 30 includes an object detection device 1, a yaw rate sensor 41 that detects a yaw rate, a wheel speed sensor 42 that detects the rotational speed of each wheel, and a winker switch 44 that is operated when the driver lights up the winker. It is connected. Further, a cruise control switch 43 that can be operated by the driver for inter-vehicle control is connected to the input of the ACC system 30. The cruise control switch 43 includes a cruise switch 61 that switches an on / off state of the inter-vehicle control function, a distance switch 62 that is operated when the driver sets the inter-vehicle distance, a driver that sets the vehicle speed, a temporary release of the inter-vehicle control function, And a set / resume / cancel switch 63 operated when resuming the inter-vehicle control function, and a traffic switch 64 operated when the driver sets the traffic volume.
[0057]
The set inter-vehicle distance can be switched between three stages: long, medium and short. The inter-vehicle distance is represented by the vehicle head time (the time it takes for the vehicle to reach the current position of the preceding vehicle when the vehicle travels at the current vehicle speed). In this example, “long” corresponds to 2.5 seconds, “medium” corresponds to 2.1 seconds, and “short” corresponds to 1.7 seconds. For example, if the vehicle speed of the host vehicle is 80 km / h, “long” corresponds to about 56 m, “medium” corresponds to about 47 m, and “short” corresponds to about 38 m.
[0058]
Traffic volume can be switched to three levels: HEAVY, MID, and LIGHT. Each traffic volume is assigned a period for returning the target inter-vehicle distance to the set inter-vehicle distance (hereinafter referred to as “return period”). In this embodiment, HEAVY is 30 seconds, MID is 15 seconds, and LIGHT is set to 5 seconds.
[0059]
The output of the ACC system 30 is connected to a throttle actuator 46 that controls the engine throttle according to an instruction from the vehicle speed control unit 56 and a brake actuator 47 that operates the brake. Further, the output of the ACC system 30 is connected to a display 48 that displays an operation state and a setting state of the inter-vehicle control according to an instruction from the inter-vehicle control unit 52, and a warning buzzer 49 that emits a buzzer according to the instruction from the inter-vehicle control unit 52. ing.
[0060]
The ACC system 30 includes a preceding vehicle determination unit 51, an inter-vehicle distance control unit 52, and a vehicle speed control unit 56. The preceding vehicle determination unit 51 estimates the travel locus of the host vehicle based on the yaw rate and the vehicle speed received from the yaw rate sensor 41 and the wheel speed sensor 42. On the other hand, the preceding vehicle determination unit 51 receives the position and relative speed of each moving object detected by the object detection device 1. The preceding vehicle determination unit 51 determines, among the moving objects received from the object detection device 1, the moving object that is present on the estimated traveling locus of the own vehicle and is closest to the own vehicle as the preceding vehicle.
[0061]
The inter-vehicle distance control unit 52 starts inter-vehicle distance control in response to the set switch and the resume switch being operated while the cruise switch 61 is in the ON state. The inter-vehicle control mode in which the vehicle travels according to the inter-vehicle control can be roughly divided into two travel modes, that is, a follow-up travel mode and a constant-speed travel mode, and each travel mode is determined by the follow-up travel unit 53 and the constant-speed travel unit 54. Be controlled.
[0062]
The following traveling mode is a traveling mode in which, when a preceding vehicle is detected by the preceding vehicle determination unit 51, the preceding vehicle is followed so that the inter-vehicle distance with respect to the preceding vehicle maintains the set inter-vehicle distance with the set vehicle speed as an upper limit. The follow-up traveling unit 53 receives the set inter-vehicle distance set via the distance switch 62, and sets this as the target inter-vehicle distance. The follow-up traveling unit 53 calculates the difference between the current inter-vehicle distance received from the preceding vehicle determining unit 51 and the target inter-vehicle distance, and calculates the target vehicle speed so that the difference becomes zero. Thus, in the follow-up running mode, the vehicle speed is always controlled so that the current inter-vehicle distance becomes the set inter-vehicle distance.
[0063]
The constant speed travel mode is a mode in which the vehicle travels to maintain the set vehicle speed when the preceding vehicle is not detected by the preceding vehicle determination unit 51. The constant speed traveling unit 54 receives the set vehicle speed set via the set / resume / cancel switch 63. The constant speed traveling unit 54 calculates the target vehicle speed in response to the determination by the preceding vehicle determining unit 51 that there is no preceding vehicle so that the current vehicle speed becomes the set vehicle speed.
[0064]
The follow traveling unit 53 and the constant speed traveling unit 54 perform deceleration control and acceleration control as necessary. In other words, the follow-up traveling unit 53 performs deceleration control so as not to approach the preceding vehicle too much when the vehicle speed of the preceding vehicle is slower than the vehicle speed of the own vehicle, and when the vehicle speed of the preceding vehicle is faster than the vehicle speed of the own vehicle, Acceleration control is performed to follow the preceding vehicle. These acceleration / deceleration controls are achieved by comparing the current inter-vehicle distance and the target inter-vehicle distance and adjusting the target vehicle speed so that the current inter-vehicle distance becomes the target inter-vehicle distance.
[0065]
In addition, the constant speed traveling unit 54 performs acceleration control so that the set vehicle speed is reached when there is no preceding vehicle in a situation where the preceding vehicle is followed at a vehicle speed slower than the set vehicle speed, for example, in a situation where there is no preceding vehicle. When the set vehicle speed is newly set to be low, deceleration control is performed so that the newly set vehicle speed is reached. These acceleration / deceleration controls are achieved by comparing the current vehicle speed with the set vehicle speed and adjusting the target vehicle speed so that the current vehicle speed becomes the set vehicle speed.
[0066]
The follow-up travel mode according to the present invention further includes a return control travel mode, and the return control travel mode is controlled by the return control travel unit 55. The return control travel mode is a travel mode in which the vehicle speed is controlled so that the inter-vehicle distance with respect to the preceding vehicle gradually returns to the set inter-vehicle distance when another vehicle interrupts in front of the own vehicle or when the own vehicle changes lanes. . The return control travel unit 55 sets the inter-vehicle distance to the preceding vehicle determined by the preceding vehicle determining unit 51 when the other vehicle interrupts or the lane change of the host vehicle occurs, and is set via the distance switch 62. If shorter, the inter-vehicle distance for the current preceding vehicle is set as the target inter-vehicle distance. The return control travel unit 55 calculates the target vehicle speed so that the current inter-vehicle distance becomes the target inter-vehicle distance. Thereafter, as will be described in detail later with reference to FIG. 5, the return control traveling unit 55 adjusts the target vehicle speed so that the target inter-vehicle distance returns to the set inter-vehicle distance over a predetermined period.
[0067]
As described above, when the inter-vehicle distance with respect to the preceding vehicle becomes equal to or less than the set inter-vehicle distance due to the interruption of another vehicle or the lane change of the own vehicle, the vehicle speed is controlled from the control by the follow-up traveling unit 53 to the return control traveling unit 55 That is, the control is switched from the control of the vehicle speed based on the set inter-vehicle distance to the control of the vehicle speed based on the target inter-vehicle distance calculated by the return control traveling unit 55.
[0068]
The inter-vehicle control unit 52 displays the current setting status and operating status of the ACC system on the display 48. In addition, the inter-vehicle distance controller 52 drives the warning buzzer 49 when it is necessary to alert the driver, for example, when the vehicle is too close to the preceding vehicle.
[0069]
The vehicle speed control unit 56 controls the throttle actuator 46 so that the target vehicle speed received from the inter-vehicle distance control unit 52 is reached. When the vehicle is decelerating, if the deceleration is not sufficient even by deceleration by the throttle control, the vehicle speed control unit 56 drives the brake actuator 47 to operate the brake.
[0070]
FIG. 5 is a more detailed functional block diagram of return control traveling unit 55 according to one embodiment of the present invention. The interruption determination unit 31 determines that an interruption has occurred when the preceding vehicle determined by the preceding vehicle determination unit 51 is different from the preceding vehicle determined in the previous cycle. In response to this, the inter-vehicle distance decrease determination unit 33 compares the inter-vehicle distance with respect to the interrupted other vehicle, that is, the new preceding vehicle, with the set inter-vehicle distance set via the distance switch 62, and the new preceding vehicle It is determined whether the inter-vehicle distance is shorter than the set inter-vehicle distance.
[0071]
The lane change determination unit 32 determines the lane change of the own vehicle based on the traveling state of the own vehicle. In this embodiment, the lane change determination unit 32 determines that the own vehicle has changed the lane in the following cases.
1) A signal indicating that the winker switch is turned on to the right or left is received from the winker switch 44.
2) The yaw rate detected by the yaw rate sensor 41 changed by a predetermined amount or more in one direction and then changed by a predetermined amount or more in the other direction.
3) The amount of movement of the stationary object detected by the object detection device 1 in the left-right direction changes by a predetermined amount or more in one direction, and then changes by a predetermined amount or more in the other direction. Reference later).
[0072]
If it is determined that the lane has been changed and the preceding vehicle has been determined by the preceding vehicle determining unit 51, the inter-vehicle distance decrease determining unit 33 compares the determined inter-vehicle distance with the set inter-vehicle distance and determines the determination. It is determined whether the inter-vehicle distance with respect to the preceding vehicle is shorter than the set inter-vehicle distance.
[0073]
If the inter-vehicle distance decrease determining unit 33 determines that the inter-vehicle distance for the preceding vehicle is shorter than the set inter-vehicle distance, the target inter-vehicle distance setting unit 34 sets the current inter-vehicle distance for the current preceding vehicle as the target inter-vehicle distance. The target vehicle speed calculation unit 35 calculates the target vehicle speed so that the inter-vehicle distance with respect to the preceding vehicle is maintained at the set target inter-vehicle distance. Thus, the return control travel mode is started. Since the current inter-vehicle distance is set as the target inter-vehicle distance as described above at the start of the return control travel mode, the host vehicle actually travels at a constant speed.
[0074]
The return amount calculation unit 36 calculates a return amount for returning the target inter-vehicle distance set by the target inter-vehicle distance setting unit 34 to the set inter-vehicle distance (that is, the difference between the set inter-vehicle distance and the target inter-vehicle distance), and calculates the return amount. The return amount per unit time is calculated by dividing by the return period (as described above, the period for returning the target inter-vehicle distance to the set inter-vehicle distance).
[0075]
The return period can be set by any method. In one embodiment of the present invention, when the target inter-vehicle distance is set due to an interruption of another vehicle, the return period is set according to the traffic volume set via the traffic switch 64. On the other hand, when the target inter-vehicle distance is set due to the lane change of the own vehicle, the return period is determined in advance. Thus, the return period can be set to a different value according to the cause of the decrease in the inter-vehicle distance with respect to the preceding vehicle. In alternative embodiments, a return period may be set for both lane changes and interrupts based on traffic set via the traffic switch 64, or return periods may be set for both lane changes and interrupts. It may be determined in advance.
[0076]
In another embodiment, the return period for interruption is automatically determined according to the set inter-vehicle distance. Normally, when the set inter-vehicle distance is set to “long”, it is considered that the traffic volume is small, so the return period is set short (for example, 5 seconds). On the contrary, when the set inter-vehicle distance is set to “short”, it is considered that there is a large amount of traffic, so the return period is set long (for example, 30 seconds).
[0077]
In yet another embodiment, the traffic volume is obtained based on the result detected by the object detection device 1 and / or the running state of the vehicle, and the return period is set according to the traffic volume. For example, the number of interruptions by other vehicles in a predetermined time is counted, and if the number of interruptions is equal to or greater than a predetermined value, it is determined that the traffic volume is large, and the return period is lengthened. Alternatively, it is determined whether the traffic volume is large or small based on the total number of objects detected by the object detection device 1 in the own lane and the adjacent lane, the number of times of deceleration control of the own vehicle in a predetermined time, and the like according to the determined traffic volume A return period may be set.
[0078]
In yet another embodiment, the return amount per unit time can be variably set over the return period. For example, the return amount per unit time is set smaller in the first part of the return period, and the return amount per unit time is increased as the target inter-vehicle distance approaches the set inter-vehicle distance.
[0079]
After shifting to the return control travel mode, the target inter-vehicle distance setting unit 34 adds the return amount per unit time to the target inter-vehicle distance set in the previous cycle, and calculates the target inter-vehicle distance in the current cycle. . The calculated target inter-vehicle distance in the current cycle is passed to the target vehicle speed calculating unit 35, where the target vehicle speed is calculated so that the current inter-vehicle distance becomes the target inter-vehicle distance. Since the target inter-vehicle distance calculated in the current cycle is greater than the current inter-vehicle distance (that is, the target inter-vehicle distance calculated in the previous cycle), deceleration control is executed unless the preceding vehicle accelerates. Thus, the target inter-vehicle distance approaches the set inter-vehicle distance for each cycle. When the target inter-vehicle distance becomes equal to the set inter-vehicle distance, the return control travel mode ends and the follow-up travel mode by the follow-up travel unit 53 is entered.
[0080]
Next, the cruise control switch 43 and the display 48 will be described with reference to FIGS. FIG. 6 shows the vicinity of the steering wheel in the vehicle. As shown in the figure, the cruise switch 61, the distance switch 62, and the traffic switch 64 are arranged on the lower right side of the steering wheel, and the set / resume / cancel switch 63 is arranged on the steering wheel. A display 48 is arranged in front of the combination meter 71, and the display 48 displays a setting state and an operating state of the ACC system.
[0081]
FIG. 7 is a diagram showing one form of the cruise switch 61, the distance switch 62, and the traffic switch 64. The cruise switch 61 shown in FIG. 7A is an ON / OFF toggle type switch integrated with the distance switch 62, and is switched ON / OFF each time the ON side is pressed. When the switch is turned on, that is, when the ACC system is activated, the indicator lamp 65 next to “ON” is turned on.
[0082]
The distance switch 62 is a switch for setting the inter-vehicle distance. As described above, the set inter-vehicle distance can be switched between three stages: long, medium, and short. Each time the DISTANCE side is pressed, “long”->“medium”->“short”-> “long”. . . And set inter-vehicle distance.
[0083]
A traffic switch 64 shown in FIG. 7B is a switch for setting the traffic volume. As described above, the traffic volume can be switched to three levels of LIGHT, MID, and HEAVY, and each corresponds to a low traffic volume, a middle traffic volume, and a high traffic volume.
[0084]
FIG. 7C shows a state transition diagram of the traffic switch 64. In the initial state when the ACC system is activated, the traffic is set to “LIGHT”. In this state, when the HEAVY side of the traffic switch is pressed, the traffic is switched to “MID”, and when the HEAVY side is further pressed, the traffic is switched to “HEAVY”. Further, when the LIGHT side is pressed while the traffic switch is “HEAVY”, the traffic is switched to “MID”, and when the LIGHT side is further pressed, the traffic is switched to “LIGHT”.
[0085]
As described above, a return period is set in advance for each traffic volume of the traffic switch 64. In this embodiment, LIGHT is set to 5 seconds, MID is set to 15 seconds, and HEAVY is set to 30 seconds. Thus, the return period is set longer as the traffic volume increases. When the driver determines that the traffic volume is large, the driver sets the traffic switch 64 to HEAVY. As a result, the initially set target inter-vehicle distance (that is, the inter-vehicle distance when interrupted or the inter-vehicle distance when changing lanes) returns to the set inter-vehicle distance over 30 seconds. Since the target inter-vehicle distance gradually returns to the set inter-vehicle distance, continuous interruptions of other vehicles can be avoided.
[0086]
On the other hand, when it is determined that the traffic volume is low, the driver sets the traffic switch 64 to LIGHT. As a result, the initially set target inter-vehicle distance (that is, the inter-vehicle distance when interrupted or changed lanes) returns to the set inter-vehicle distance over 5 seconds. In this way, when the traffic volume is small, it is possible to return to the set inter-vehicle distance relatively quickly and shift to follow-up traveling.
[0087]
FIG. 8 is a diagram illustrating another form of the cruise switch, the distance switch, and the traffic switch. In the switch form of FIG. 8, the cruise switch and the distance switch are of the same type as in FIG. The traffic switch shown in FIG. 8B is a dial switch, and the return period can be adjusted continuously. (C) of FIG. 8 is the figure which looked at the traffic switch of (b) of FIG. 8 from the side. As apparent from FIG. 8C, the return period can be arbitrarily set between 5 seconds and 30 seconds by turning the dial to the LIGHT side or HEAVY side. The return period is set according to where the mark indicated by the arrow 66 is positioned.
[0088]
FIG. 9 is a diagram showing still another form of the cruise switch, the distance switch, and the traffic switch. The cruise switch shown in (a) of FIG. 9 is an ON / OFF toggle type cruise switch, and is switched ON / OFF each time it is pressed. When the switch is in the ON state, the lamp 67 next to the ON display is turned on. The switch shown in FIG. 9B is a switch in which a distance switch and a traffic switch are integrated. When the LONG side is pressed, the set inter-vehicle distance increases by one step and the return period decreases by one step. When the SHORT side is pressed, the set inter-vehicle distance decreases by one step, and the return period increases by one step. In general, when the set inter-vehicle distance is set to “long”, it is considered that the traffic volume is small. Therefore, a function for increasing the set inter-vehicle distance is assigned to a function for shortening the return period. On the other hand, when the set inter-vehicle distance is set to “short”, it can be considered that there is a large amount of traffic. Therefore, a function for extending the return period is assigned to the function for shortening the set inter-vehicle distance.
[0089]
Assuming that the set inter-vehicle distance and the traffic volume are switched in three stages as described with reference to FIG. 7, when the set inter-vehicle distance is “short”, the return period is set to 30 seconds, and the set inter-vehicle distance is When “medium”, the return period is set to 15 seconds, and when the set inter-vehicle distance is “long”, the return period is set to 5 seconds. In the case of such a switch form, the traffic volume and the corresponding return period are automatically set simultaneously with setting the set inter-vehicle distance. FIG. 9C shows an alternative to the switch shown in FIG. 9B, and a display is provided on the switch so that it can be seen that both the distance switch and the traffic switch are used.
[0090]
FIG. 10 is a diagram showing still another form of the cruise switch, the distance switch, and the traffic switch, and the cruise switch, the distance switch, and the traffic switch are provided independently. The cruise switch shown in FIG. 10 (a) is the same as the cruise switch shown in FIG. 9 (a). The distance switch shown in (b) of FIG. 10 has the same form as the distance switch of (b) of FIG. 9, but has only a function of setting the set inter-vehicle distance. The traffic switch shown in (c) of FIG. 10 is the same as the traffic switch shown in (b) of FIG.
[0091]
Thus, although various switch forms were shown, it is not limited to these switch forms, The switch form of another form is employable. The ACC system according to the present invention can be applied to both the above switch form and other switch forms.
[0092]
The set / resume / cancel switch 63 shown in FIG. 11 includes a SET switch, a CANCEL switch, and a RESUME switch. The SET switch is a switch for setting the vehicle speed. When the accelerator switch is adjusted to reach a desired vehicle speed and the SET switch is pressed and released, the vehicle speed at the time of release is set as the set vehicle speed. After setting the vehicle speed, each time the RESUME switch is pressed, the set vehicle speed can be increased by a predetermined amount (for example, 2 km / h). Conversely, each time the SET switch is pressed once, the predetermined amount (for example, 2 km) / H), the set vehicle speed can be reduced. The CANCEL switch is a switch for temporarily canceling the inter-vehicle control by the ACC system. Even after the cancellation, when the set vehicle speed is displayed on the display 48 (FIG. 12), the inter-vehicle distance control can be resumed by pressing the RESUME switch.
[0093]
FIG. 12 shows a display example of the display 48. The RADER / OFF display indicated by reference numeral 75 is displayed for a predetermined time (for example, 5 seconds) when the ACC system is automatically released. The set vehicle speed is displayed in the area of reference numeral 76. While accelerating to the set vehicle speed, the vehicle speed blinks. The “NO TARGET” display indicated by reference numeral 77 is displayed when a preceding vehicle is not detected.
[0094]
The display of the car with the reference number 78 indicates the preceding car, and is displayed when the preceding car is detected. The display of the car of the reference number 80 shows the own vehicle. A set inter-vehicle distance is displayed in an area indicated by a reference number 79 between the preceding vehicle 78 and the host vehicle 80. The set inter-vehicle distance is displayed with a bar of three levels (long, medium and short). As shown in FIG. 12B, the set inter-vehicle distance is set to “long” when there are three bars, “medium” when two bars are set, and “short” when one bar is set. Indicates that The “BRAKE” display indicated by reference number 81 blinks together with a warning buzzer when a brake operation by the driver is necessary, such as when the vehicle is too close to the preceding vehicle.
[0095]
FIG. 12C is a diagram showing a part of the display 48 shown in FIG. The mark 82 shown in the figure indicates that the set inter-vehicle distance is set to “short” and the vehicle is currently traveling in the return control traveling mode. In this way, it is possible to determine for which set inter-vehicle distance the vehicle speed control based on the target inter-vehicle distance set by the return control traveling unit 55 is currently executed based on the location where the mark 82 is lit. . (D) of FIG. 12 shows an example in which the mark 82 is lit at “medium” of the set inter-vehicle distance, and (e) of FIG. 12 shows the mark 82 at “long” of the set inter-vehicle distance. An example of lighting is shown. In another embodiment, when the set inter-vehicle distance is set to “medium”, as shown in FIG. 12 (f), the mark 82 is lit at two places “medium” and “short”. When the inter-vehicle distance is set to “long”, it is lit at three places as shown in FIG.
[0096]
FIG. 13 is a diagram for explaining a preceding vehicle determination method executed by the preceding vehicle determination unit 51. A triangular area 92 indicates a detection area that can be detected by the object detection device mounted on the host vehicle 90. On the other hand, the preceding vehicle determination unit 51 assumes a constant-speed circular motion from the yaw rate and vehicle speed detected by the yaw rate sensor 41 and the wheel speed sensor 42, thereby making a traveling locus (referred to as an estimated own vehicle locus) 93 of the own vehicle. calculate. Next, the preceding vehicle determination unit 51 calculates, as the estimated own lane 94, a region having a predetermined width around the estimated own vehicle locus 93 (for example, a region of ± 2 m around the estimated own vehicle locus 93). . That is, a region sandwiched between two curves 95 is calculated as the estimated own lane 94. The preceding vehicle determination unit 51 determines, among the moving objects detected by the object detection device, the object closest to the own vehicle among the objects existing in the region where the estimated own lane 94 and the detection area 92 overlap with each other as the preceding vehicle 91. To do. In addition, when the curvature of the road changes, the preceding vehicle will deviate from the estimated own lane, so it is preferable to perform interpolation under certain conditions.
[0097]
FIG. 14 shows one of the determination methods executed by the lane change determination unit 32 of the return control traveling unit 55, that is, the amount of movement of the stationary object detected by the object detection device 1 in one direction. It is a figure for demonstrating the method of determining with the own vehicle having changed the lane, when it changes more than a predetermined amount to the other direction after changing to a predetermined amount. In this embodiment, the amount of movement of the position of the stationary object in the left-right direction is measured by detecting the change in the angle between the vehicle and the stationary object. FIG. 14 shows a state in which the own vehicle 200 changes the lane to the right overtaking lane. It is assumed that a stop 210 exists in front of the host vehicle 200 on the right side.
[0098]
In FIG. 14A, the host vehicle 200 is traveling in the direction of the arrow 220. The object detection device mounted on the host vehicle 200 detects the stopped object 210 and detects the distance D1 and the left and right position w1. Here, the left and right position w1 is represented by + when the vehicle is on the right side with respect to the own vehicle 200, and is represented by-when the vehicle is on the left side. An angle (called a stop object angle) θ1 formed by the traveling direction of the host vehicle and the stop object is expressed as sin θ1 = w1 / D1.
[0099]
Next, as shown in FIG. 14B, the host vehicle 200 changes its course in the direction of the arrow 221 to change the lane. The object detection device 1 detects the stop object 210 and detects the distance D2 and the left-right position w2. The stop object angle θ2 is expressed by sin θ2 = w2 / D2. Thereafter, as shown in FIG. 14C, the host vehicle 200 completes the lane change and travels back in the direction of the arrow 222. The object detection device 1 detects the stop object 210 and detects the distance D3 and the left-right position w3. The stop object angle θ3 is expressed by sin θ3 = w3 / D3.
[0100]
The graph of (d) of FIG. 14 shows the transition of the stop object angle θ in (a) to (c) of FIG. The stop object angle sinθ changes in a negative direction as the vehicle changes its direction to change lanes, and changes in a positive direction as the vehicle returns to return again in an attempt to complete the lane change. This is the same when a stop is present on the left side of the vehicle. Accordingly, when the stop object angle changes in the negative direction by a predetermined amount or more and then changes in the positive direction by a predetermined amount or more, it can be determined that the host vehicle has changed to the right lane. When the amount of change per unit time of the stop object angle is called a lateral movement angle, if the lateral movement angle shows a negative value smaller than a predetermined value and then a positive value larger than a predetermined value, Can be determined to have changed to the right lane. On the contrary, if the lateral movement angle shows a positive value larger than a predetermined value and then shows a negative value smaller than the predetermined value, it can be determined that the own vehicle has changed to the left lane.
[0101]
FIG. 15 is a flowchart showing an operation in the ACC system for realizing the return control travel mode, the follow travel mode, and the constant speed travel mode according to one embodiment of the present invention. This flowchart is repeatedly executed in a predetermined cycle (in this embodiment, a cycle of 100 milliseconds). Steps 301 and 302 indicate the object detection process executed by the object detection apparatus 1 as described above with reference to FIG. That is, all the targets in the detection area are detected and stored in the target memory, and the stored target data is classified into a moving object and a stopped object. On the other hand, as described above with reference to FIG. 13, the preceding vehicle determination unit 51 calculates the estimated own lane of the own vehicle based on the yaw rate and the vehicle speed (303). In step 304, a lane change determination routine is executed to determine whether or not the vehicle has changed lanes. In step 305, among the moving object targets classified in step 302, those existing on the estimated own lane calculated in step 303 are determined as preceding vehicles.
[0102]
Proceeding to step 306, if the preceding vehicle is determined by the preceding vehicle determining unit 51, a target inter-vehicle distance determining routine for determining the target inter-vehicle distance is executed (307). Based on the target inter-vehicle distance determined in this routine, fixed inter-vehicle travel is executed (308). That is, the current inter-vehicle distance with respect to the preceding vehicle is compared with the target inter-vehicle distance. If the former is larger than the latter, acceleration control is performed (309). If the former is the same as the latter, constant speed control is performed (311). If it is smaller than the latter, deceleration control is performed (312).
[0103]
If it is determined in step 306 that there is no preceding vehicle, the target inter-vehicle distance is reset to the set inter-vehicle distance set via the distance switch (313). This is because there is no need to adjust the target inter-vehicle distance because there is no preceding vehicle. In step 314, the current vehicle speed of the host vehicle is compared with the set vehicle speed set via the set / resume / cancel switch 63. If the former is larger than the latter, deceleration control is performed (315), if the former and the latter are the same, constant speed control is performed (316), and if the former is smaller than the latter, acceleration control is performed (317). Thus, constant speed running is executed.
[0104]
FIG. 16 is a flowchart of a lane change determination routine executed in step 304 of FIG. In order to avoid complication of the explanation, in this embodiment, it is assumed that the traffic environment of left-hand traffic is assumed, and the own vehicle traveling in the left lane is changed to the right overtaking lane.
[0105]
In step 331, it is determined whether or not the winker switch is turned on to the right. If it is turned on, the process proceeds to step 345, where the lane change flag is turned on. If not, go to step 332.
[0106]
Steps 332 to 337 are steps for determining whether or not a lane change has been made based on the yaw rate value. When the vehicle changes lanes from the left lane to the right lane, the vehicle turns to the right and then turns to the left, so the yaw rate value shows a negative value after showing a positive value (turning to the right The direction to turn is positive and the direction to turn left is negative). In this example, if the yaw rate value shows a value of +2 degrees / second or more and then shows a value of -2 degrees / second or more within 6 seconds (that is, a negative value smaller than -2 degrees / second), the lane Judge that there is a change. Note that these values are merely examples, and other arbitrary values may be set.
[0107]
In step 332, the current yaw rate value is compared with -2 degrees / second. As described above, when changing lanes, the vehicle first turns to the right, so the yaw rate shows a positive value. Accordingly, the process proceeds to step 334, and the current yaw rate value is compared with +2 degrees / second. If the yaw rate value indicates +2 degrees / second or more, the right yaw flag is turned on (335). When this routine is entered in the next cycle, in step 332, the current yaw rate value is compared with -2 degrees / second. Since the yaw rate value when the lane change is about to end is a value lower than -2 degrees / second, the routine proceeds to step 333, where it is determined whether the right yaw flag is on. If the right yaw flag is on, it indicates that the vehicle has made a left turn within a predetermined time after turning right (that is, within 6 seconds after the right yaw flag was turned on in step 335). Turn on the flag. Thus, it is determined from the change in the yaw rate value whether or not the vehicle has changed lanes.
[0108]
In step 336, the right yaw flag after 6 seconds or more is turned off. 6 seconds is a value set with a margin for the time required to change lanes. In step 337, the lane change flag after 3 seconds or more is turned off. The lane change flag is a flag that is set when the lane change is completed (set in step 345). 3 seconds is a value set with a margin for the time required for the subsequent processing in this cycle to end.
[0109]
Next, steps 338 to 344 are steps for determining whether or not the own vehicle has changed lanes based on the lateral movement angle of the stationary object. As described above, the lateral movement angle indicates the amount of change per unit time of the angle formed by the host vehicle and the stopped object. When the vehicle changes lanes to the right lane, the vehicle turns to the left and then turns to the left, so that the lateral movement angle of the stationary object shows a negative value and then a positive value (see FIG. 14). As described above with reference, the lateral movement angle of the stationary object when the vehicle turns to the right is negative). In this embodiment, in order to more accurately determine the lane change, as shown in the following formula, the average of the lateral movement angles for all the stationary objects detected by the object detection device is calculated, and according to the average value Determine if a lane change has been made.
[0110]
[Expression 2]
Average lateral movement angle of all stationary targets =
Σ (Transverse angle of all stationary targets) / Number of all stationary targets
[0111]
In this embodiment, if the lateral movement angle shows a value of −2 degrees / second or more and then shows +2 degrees / second or more within 6 seconds, it is determined that there is a lane change. However, these values are merely examples, and other arbitrary values can be set.
[0112]
In step 339, the average value of the lateral movement angles of all stationary objects is compared with +2 degrees / second. As described above, when changing lanes, the vehicle turns to the right first, so the average value shows a negative value. Therefore, the process proceeds to step 341, and the average value is compared with -2 degrees / second. If the average value of the lateral movement angle shows a value of −2 degrees / second or less, the left movement flag is turned on (342).
[0113]
Next, when this routine is entered, similarly, in step 339, the current average value of the lateral movement angle is compared with +2 degrees / second. When the lane change is about to end, the average value indicates a value of +2 degrees / second or more, so the process proceeds to step 349 to determine whether the left movement flag is on. If the left travel flag is on, it indicates that the vehicle has made a left turn within a predetermined time (within 6 seconds after the left travel flag was turned on in step 362) after turning right. Turn on the flag. Thus, it is determined from the average value of the lateral movement angle whether or not the vehicle has changed lanes. In step 343, the left movement flag after 6 seconds or more is turned off, and in step 344, the lane change flag after 3 seconds or more is turned off.
[0114]
In the lane change determination routine of FIG. 16, the lane change determination based on the blinker switch in step 331, the lane change determination based on the yaw rate in steps 332 to 337, and the lane change determination based on the lateral movement angle of the stationary object in steps 338 to 344 are performed. , They can be executed in parallel, or any of these can be combined to determine lane changes.
[0115]
FIG. 17 is a flowchart of a target inter-vehicle distance determination routine executed in step 307 of FIG. In step 351, the set inter-vehicle distance set via the distance switch 62 is read, and it is determined whether it is the same as the set inter-vehicle distance in the previous cycle (352). If the set inter-vehicle distance in the previous cycle is different from the set inter-vehicle distance in the current cycle, the set inter-vehicle distance read in step 351 is set as the target inter-vehicle distance (353). This is to perform fixed inter-vehicle travel based on the new set inter-vehicle distance.
[0116]
If it is determined in step 352 that the set inter-vehicle distance in the previous cycle is the same as the set inter-vehicle distance in the current cycle, the process proceeds to step 354, and the lane change flag is checked for on / off. As described above, the lane change flag is a flag that is set to ON in step 345 (FIG. 16) when it is determined that the vehicle has changed lanes. If the lane change flag is on, it indicates that the lane change of the own vehicle has occurred, so the processing shown in steps 355 to 358 is executed to determine the target inter-vehicle distance. That is, in step 355, it is determined whether the current vehicle head time is 0.7 seconds or more. For example, 0.7 seconds indicates a distance corresponding to about 15.6 m when the vehicle speed of the host vehicle is 80 km / h. The determination in step 355 is performed to determine whether or not the own vehicle is too close to the preceding vehicle. Note that 0.7 seconds is merely an example, and other values may be used.
[0117]
If the current vehicle head time is 0.7 seconds or more in step 355, the process proceeds to step 356, where the set inter-vehicle distance is compared with the current inter-vehicle distance with respect to the preceding vehicle. If the current inter-vehicle distance is larger than the set inter-vehicle distance, the vehicle speed may be controlled so as to be the set inter-vehicle distance as usual. In step 356, if the current inter-vehicle distance is less than or equal to the set inter-vehicle distance, the current inter-vehicle distance is set as the target inter-vehicle distance (357). Thereby, the target inter-vehicle distance for which the set inter-vehicle distance has been set is replaced with the current inter-vehicle distance. In this case, since the target inter-vehicle distance is the same value as the current inter-vehicle distance, the vehicle speed is substantially controlled at a constant speed (step 311 in FIG. 15). Proceeding to step 359, the return amount calculation routine is executed to calculate the return amount per unit time. This return amount is added to the target inter-vehicle distance in the next and subsequent cycles.
[0118]
In step 355, if the current vehicle head time is smaller than 0.7 seconds, the process proceeds to step 358, and a distance corresponding to the vehicle head time 0.7 seconds (as described above, if the vehicle speed of the host vehicle is 80 km / h, about 15 .6m) is set as the target inter-vehicle distance. This is because the vehicle is too close to the preceding vehicle as a result of the lane change, so that the inter-vehicle distance is increased to a distance corresponding to the vehicle head time of 0.7 seconds to maintain safety.
[0119]
Returning to step 354, if the lane change flag is not on, the routine proceeds to step 361, where it is determined whether the preceding vehicle determined in the previous cycle is the same as the preceding vehicle determined in the current cycle. As described with reference to FIG. 3, this is because the identity of the object is determined in the moving object target takeover process, and based on the determination result and the determination result of the preceding vehicle by the preceding vehicle determination unit 51. Can be judged.
[0120]
If the preceding vehicle determined in the previous cycle is different from the preceding vehicle determined in the current cycle, this indicates a situation where the own vehicle is interrupted by a new vehicle. Proceeding to step 362, it is determined whether or not a preceding vehicle has been determined in the previous cycle. If the preceding vehicle has been determined in the previous cycle, it indicates that the vehicle has been interrupted by a new vehicle while following the vehicle. Therefore, the steps after step 355 are executed, and the above lane change is executed. The target inter-vehicle distance is determined as in the case. In step 362, if the preceding vehicle has not been determined in the previous cycle, it indicates that the vehicle has been interrupted by a new vehicle when traveling at a constant speed, so the routine is exited.
[0121]
Returning to step 361, if the preceding vehicle determined in the previous cycle and the preceding vehicle determined in the current cycle are the same, it indicates that the host vehicle is following the same preceding vehicle in the previous and current cycles. . Proceeding to step 363, it is determined whether or not the target inter-vehicle distance is equal to the set inter-vehicle distance. If they are not equal, the routine proceeds to step 364, where the return amount per unit time calculated by the return amount calculation routine of step 359 is added to the target inter-vehicle distance determined in the previous cycle to obtain the target inter-vehicle distance in the current cycle. . Thus, the target inter-vehicle distance approaches the set inter-vehicle distance for each cycle by the amount of return per unit time.
[0122]
FIG. 18 is a flowchart showing a return amount calculation routine executed in step 359 of FIG. In this embodiment, the return period when the inter-vehicle distance is reduced due to the lane change is determined to be 3 seconds in advance. When the inter-vehicle distance is reduced due to an interruption of another vehicle, the return period is set based on the setting of the traffic switch 64. Specifically, in the traffic switch 64, LIGHT is preset to 5 seconds, MID is set to 15 seconds, and HEAVY is set to 30 seconds. Further, as described above, the processing cycle of this routine is assumed to be 100 milliseconds.
[0123]
In step 371, the difference between the set inter-vehicle distance and the target inter-vehicle distance, that is, the return amount is calculated. As described with reference to FIG. 17, the target inter-vehicle distance is set in step 357 or 358. Proceeding to step 372, it is determined whether the lane change flag is on. This is to determine whether the decrease in the inter-vehicle distance is caused by the lane change of the own vehicle or the interruption of another vehicle. If the lane change flag is on, it indicates that the inter-vehicle distance has decreased due to the lane change of the own vehicle. Proceeding to step 373, the return amount per unit time is obtained. That is, since the return period is 3 seconds and the processing cycle is 100 milliseconds (that is, 10 cycles are executed per second), the return amount calculated in step 371 is divided by 30. Thus, in each cycle, the target inter-vehicle distance approaches the set inter-vehicle distance by the calculated return amount per unit time.
[0124]
If the lane change flag is not on in step 372, it indicates that the inter-vehicle distance has decreased due to the interruption of another vehicle. Proceeding to step 374, the setting of the traffic switch 64 is read. If the traffic switch is set to LIGHT, the return period is 5 seconds. Therefore, the return amount calculated in step 371 is divided by 50 (376). If the traffic switch is set to MID, the return period is 15 seconds. Therefore, the return amount calculated in step 371 is divided by 150 (377). If the traffic switch is set to HEAVY, the return period is 30 seconds. Therefore, the return amount calculated in step 371 is divided by 300 (378). As described above, the larger the set traffic volume (that is, the longer the return period), the smaller the return amount per unit time. Thereby, since it returns to the setting inter-vehicle distance more gently as the traffic volume increases, it is possible to return to the follow-up traveling based on the set inter-vehicle distance while avoiding continuous interruption.
[0125]
In this embodiment, when the inter-vehicle distance is reduced due to the lane change, a shorter return period is set than when the inter-vehicle distance is reduced due to the interruption. This is because, in the case of a lane change, there is a case where there is no need to gently return to the set inter-vehicle distance depending on the situation of the lane to be changed (for example, no interruption occurs in the lane to be changed). . Therefore, after changing lanes, the vehicle shifts to follow-up traveling relatively quickly. However, as described above, how to set the return period in the case of lane change and in the case of interruption is arbitrary, and different values may be set as described above, or the same value may be set. May be.
[0126]
A method for automatically optimizing the return period based on the number of interrupts according to another embodiment of the present invention will now be described with reference to FIGS. That is, the number of times interrupted by another vehicle is counted, and when the number of interruptions exceeds a predetermined number, the return period is automatically lengthened by a predetermined value.
[0127]
The target inter-vehicle distance determination routine of FIG. 19 is different from FIG. 17 in that steps 365 and 366 are added. Step 365 increments the interrupt counter when it is determined that an interrupt by another vehicle has occurred. Here, the interrupt counter is a counter that counts the number of times interrupted during the return period. Step 366 resets the interrupt counter when the target inter-vehicle distance returns to the set inter-vehicle distance and when the set inter-vehicle distance setting is changed. The reset of the interrupt counter is also reset when performing constant speed running, that is, in step 313 of FIG. 15 (not shown).
[0128]
FIG. 20 is a flowchart of the return amount calculation routine executed in step 359 of FIG. As apparent from the comparison with FIG. 18, the method of obtaining the return amount per unit time in the lane change is the same as that in FIG. When it is determined that the interrupt is detected, it is determined in step 381 whether or not the value of the interrupt counter is equal to or greater than a predetermined number (for example, 3). Any value can be used as the predetermined number of times in this embodiment. The predetermined number of times may be changed according to the length of the current return period. If the value of the interrupt counter is smaller than the predetermined number, the process proceeds to step 382, and the return period is set to 30 seconds. This 30 seconds is merely an example, and other values may be set. On the other hand, if the value of the interrupt counter is equal to or greater than the predetermined number, the process proceeds to step 383, and the return period is set to “30 seconds + (interrupt counter value × predetermined value)”. The predetermined value is 2 seconds in this embodiment. However, this predetermined value may be another value. Thus, the return period is automatically set longer by a predetermined value according to the number of interrupts. Proceeding to step 384, the return amount per unit time is obtained based on the return period obtained at steps 382 and 383.
[0129]
FIG. 21 is a diagram schematically showing the operation of the ACC system of the present invention. In the figure, numbers {circle around (1)}, {circle around (2)} assigned to the respective vehicles are numbers for identifying the respective vehicles. In host vehicle 400, it is assumed that the set vehicle speed is 100 km / h, the set inter-vehicle distance is “short”, and traffic switch 64 is set to HEAVY. In this embodiment, it is assumed that the “short” of the set inter-vehicle distance corresponds to about 42.5 m, and the HEAVY of the traffic switch corresponds to a return period of 30 seconds. One cycle is assumed to be 100 milliseconds.
[0130]
First, as shown in FIG. 21A, the own vehicle 400 detects the first other vehicle 410 as a preceding vehicle. The own vehicle 400 follows the vehicle so that the distance from the first other vehicle 410 is maintained at the set inter-vehicle distance of 42.5 m. FIG. 21B shows a situation in which the second other vehicle 420 has changed lanes and has interrupted between the host vehicle 400 and the first other vehicle 410. The own vehicle 400 detects the second other vehicle 420, sets the inter-vehicle distance 20.0 meters to the other vehicle 420 as the target inter-vehicle distance, and shifts to the return control travel mode. Thus, the own vehicle 400 follows the second other vehicle 420 while maintaining the current inter-vehicle distance. Thereafter, as described with reference to FIG. 18, the difference 22.5 m between the set inter-vehicle distance and the current target inter-vehicle distance is calculated. In the ACC system mounted on the host vehicle 400, since the setting of the traffic switch 64 is HEAVY, the calculated target inter-vehicle distance return amount 22.5 is divided by 300 (30 seconds × 10 times). As a result, the return amount per cycle is calculated as 0.075 m.
[0131]
FIG. 21C shows a state after 6 seconds from FIG. Since the return amount per cycle was calculated to be 0.075 m, the distance between the vehicles approached the set inter-vehicle distance by 4.5 m after 6 seconds. Since the inter-vehicle distance between the host vehicle 400 and the second other vehicle 420 is relatively short at 24.5 m, there is no possibility of being interrupted by the other vehicle.
[0132]
FIG. 21D shows a state 12 seconds after the situation of FIG. During the 12 seconds, the target inter-vehicle distance approaches the set inter-vehicle distance by 9 m. After all, since the inter-vehicle distance between the own vehicle 400 and the second other vehicle 420 is relatively short at 29.0 m, there is no possibility of being interrupted by the other vehicle. FIG. 21E shows a state 30 seconds after the situation of FIG. The target inter-vehicle distance becomes equal to the set inter-vehicle distance over 30 seconds. At this time, the own vehicle 400 shifts to a follow-up running mode in which the inter-vehicle distance with respect to the second other vehicle 420 is maintained at the set inter-vehicle distance. As apparent from the comparison with FIG. 22, according to the present invention, the vehicle travels while gradually returning the target inter-vehicle distance to the set inter-vehicle distance, so that the following travel based on the set inter-vehicle distance is avoided while avoiding continuous interruption by other vehicles. You can return to
[0133]
【The invention's effect】
According to the present invention, during traveling between fixed vehicles, the inter-vehicle distance can be automatically adjusted according to the congestion situation of surrounding roads, and continuous interruptions by other vehicles and unnecessary deceleration of the host vehicle can be avoided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an object detection device according to an embodiment of the present invention.
FIG. 2 is a diagram showing an area detected by an object detection device according to an embodiment of the present invention.
FIG. 3 is a flowchart showing an object detection method according to an embodiment of the present invention.
FIG. 4 is a functional block diagram of an ACC system in one embodiment of the present invention.
FIG. 5 is a more detailed functional block diagram of a return control unit of the ACC system in one embodiment of the present invention.
FIG. 6 is a diagram showing an arrangement of a switch for operating the ACC system and a display for displaying information about the ACC system in one embodiment of the present invention.
FIG. 7 is a diagram showing one form of a cruise switch, a distance switch, and a traffic switch in one embodiment of the present invention.
FIG. 8 is a diagram showing another form of a cruise switch, a distance switch, and a traffic switch in one embodiment of the present invention.
FIG. 9 is a diagram showing still another form of a cruise switch, a distance switch, and a traffic switch in an embodiment of the present invention.
FIG. 10 is a diagram showing still another form of a cruise switch, a distance switch, and a traffic switch in an embodiment of the present invention.
FIG. 11 is a diagram showing one form of a set / resume / cancel switch according to an embodiment of the present invention;
FIG. 12 is a view showing a display example of a display in one embodiment of the present invention.
FIG. 13 is a diagram showing a method for determining a preceding vehicle in one embodiment of the present invention.
FIG. 14 is a diagram showing a method of determining lane change from the left-right direction and the amount of movement of a stop in one embodiment of the present invention.
FIG. 15 is a flowchart showing a method for controlling follow-up running and constant speed running in one embodiment of the present invention.
FIG. 16 is a flowchart showing lane change determination in one embodiment of the present invention.
FIG. 17 is a flowchart showing a target inter-vehicle distance determination routine in one embodiment of the present invention.
FIG. 18 is a flowchart showing a return amount calculation routine in one embodiment of the present invention.
FIG. 19 is a flowchart showing a target inter-vehicle distance determination routine in another embodiment of the present invention.
FIG. 20 is a flowchart showing a return amount calculation routine according to another embodiment of the present invention.
FIG. 21 is a diagram showing an outline of the operation of the ACC system according to one embodiment of the present invention;
FIG. 22 is a diagram showing an outline of the operation of a conventional ACC system.
[Explanation of symbols]
1 object detection device 51 preceding vehicle determination unit
52 Vehicle-to-vehicle control unit 53 Follow-up traveling unit
54 Constant speed traveling section 55 Return control traveling section
56 Vehicle speed controller
31 Interruption determination unit 32 Lane change determination unit
33 Inter-vehicle distance decrease determination unit 34 Target inter-vehicle distance setting unit
35 Target vehicle speed calculator

Claims (4)

An inter-vehicle distance detecting means for determining a preceding vehicle that the host vehicle should follow and detecting an inter-vehicle distance with respect to the preceding vehicle, an inter-vehicle distance setting means for presetting an inter-vehicle distance with respect to the preceding vehicle, and the preceding detected by the inter-vehicle distance detecting means In an auto cruise device comprising an inter-vehicle control means for controlling the vehicle speed so that the inter-vehicle distance with respect to the vehicle maintains the inter-vehicle distance set by the inter-vehicle distance setting means,
An inter-vehicle distance decrease determination unit that determines that the inter-vehicle distance detected by the inter-vehicle distance detection unit has decreased to a value less than or equal to the inter-vehicle distance set by the inter-vehicle distance setting unit due to an interruption of another vehicle in the traveling direction of the host vehicle. When,
A target inter-vehicle distance setting unit that sets the inter-vehicle distance detected by the inter-vehicle distance detection unit as a target inter-vehicle distance in response to the determination that the inter-vehicle distance decrease is determined by the inter-vehicle distance decrease determination unit;
Traffic volume setting means for setting the traffic volume around the vehicle;
Return amount corresponding to the difference between the target inter-vehicle distance and the set inter-vehicle distance is divided by the set return time as traffic amount set by the traffic amount setting means, per unit time of the vehicle distance A return amount calculating means for calculating a return amount;
When the target inter-vehicle distance is set by the target inter-vehicle distance determining unit, the inter-vehicle control means sets the inter-vehicle distance for the preceding vehicle from the control of the vehicle speed that maintains the inter-vehicle distance at the set inter-vehicle distance. Switching to control, and controlling the vehicle speed so that the set target inter-vehicle distance is gradually returned to the set inter-vehicle distance based on the return amount per unit time.
Auto cruise device.   The inter-vehicle control means calculates the target inter-vehicle distance in the current cycle by adding the return amount per unit time calculated by the return amount calculating means to the target inter-vehicle distance in the previous cycle, and calculates the calculated current inter-vehicle distance. The auto-cruise device according to claim 1, wherein the vehicle speed is controlled so as to be a target inter-vehicle distance in a cycle. The auto-cruise device according to claim 1 or 2, wherein the return period is set longer as the traffic volume set by the traffic volume setting means is larger. The auto cruise device according to claim 1 or 2, wherein the traffic volume setting means includes a switch operable by a user to set the traffic volume .

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