JP2012160103A - Object detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the effect of preventing collision with another vehicle or the like in simple configuration.SOLUTION: An object detection system includes an object detection sensor which is provided at a front side of a vehicle to detect a distance between an object on the side of the vehicle and the vehicle, a distance/speed detection unit which acquires the distance between the object and the vehicle on the basis of output from the object detection sensor and detects a relative speed of the object, a distance/speed information storage unit which stores the distance to the object and the relative speed of the object detected by the distance/speed detection unit, a collision warning determination unit which determines the possibility to collide with the object on the basis of the distance to the object and the relative speed of the object, and a warning device which outputs a predetermined warning when the collision warning determination unit determines that there is a possibility of collision with the object.

Description

  The present invention relates to a technique for detecting that an object (for example, a two-wheeled vehicle, a four-wheeled vehicle, a person, etc.) is approaching the vehicle from the side.

  Japanese Patent Laying-Open No. 2005-173703 (Patent Document 1) discloses an intersection collision prevention apparatus for preventing a collision with another vehicle or the like when the host vehicle enters an intersection or a junction. In this intersection collision prevention apparatus, when the host vehicle approaches a predetermined distance from an intersection or junction where there is no signal, the risk calculation execution determination unit determines that the host vehicle is in an environment for risk calculation execution. To do. The collision risk determination unit calculates the risk based on the outputs from the right side sensor and the left side sensor in the environment, and monitors the driver's intention to start based on the output from the brake pedal force sensor. The warning determination unit warns the driver via a warning device when there is a risk of collision based on these pieces of information.

  By the way, the intersection collision prevention device of the preceding example only warns the driver of the collision risk of the two-wheeled vehicle, and excludes the collision warning of the four-wheeled vehicle. However, there is also a demand that warnings should be given to those that may collide with the host vehicle, regardless of whether they are two-wheeled or four-wheeled.

  In recent years, there are many elderly drivers, and there is a tendency to increase further in the future. Although such an elderly driver confirms the opponent vehicle, it often causes a collision accident because the speed of the opponent vehicle cannot be accurately recognized. This is one of the characteristics of accidents caused by elderly people. For this reason, there is also a demand to detect a vehicle having a possibility of collision not only in the vicinity of the own vehicle but also in a wide range.

  In addition, the earlier this type of warning, the higher the possibility of collision avoidance. However, in the preceding intersection collision prevention apparatus, intersection detection processing, four-wheel movement direction determination processing, non-four-wheel movement direction determination processing, own vehicle Since many processes such as a moving direction detection process, an operation state determination process, a driver attention level determination process, a collision risk level calculation process, a collision direction determination process, and a warning determination process are performed, it takes time until the alarm. Furthermore, since it is assumed that road information necessary for a part of the processing is acquired from the navigation system, there is a disadvantage that the entire system becomes expensive or cannot be applied to a vehicle not equipped with the navigation system.

Japanese Patent No. 4396250

  The specific aspect which concerns on this invention makes it one of the objectives to provide the technique which can heighten the effect which prevents the collision with other vehicles etc. with a simple structure.

  An object detection system according to an aspect of the present invention is an object detection system that detects an object that may collide with a vehicle, and is (a) provided in front of the vehicle and present on a side of the vehicle. An object detection sensor for detecting a distance between the object and the vehicle; and (b) a distance for acquiring a distance between the object and the vehicle based on an output from the object detection sensor and detecting a relative speed of the object. A speed detection unit; and (c) a distance / speed information storage unit that stores the distance and the relative speed of the object detected by the distance / speed detection unit; and (d) the distance and the relative of the object. A collision warning determination unit that determines the possibility of collision of the object based on speed; and (e) outputs a predetermined warning when the collision warning determination unit determines that there is a possibility of collision of the object. Including alarm device to do Constructed.

  In the object detection system described above, all types of objects (for example, vehicles, bicycles, humans, etc.) existing on the side of the host vehicle can be detected without distinguishing between two wheels and four wheels. Also, since the necessity of warning is determined by taking into account the speed and relative distance of the target object, for example, if there is an object that is far away from the host vehicle but has a large relative speed, the need for warning On the other hand, if the object is close to the host vehicle but the relative speed is 0 or a low-speed object, it is determined that there is no need for the alarm. it can. Thereby, the detection range can be extended to a far distance while avoiding the alarm being output more than necessary. Furthermore, since a series of processes until the determination of the presence or absence of an alarm is simplified, the processing time can be shortened. As described above, the effect of preventing a collision with another vehicle or the like can be enhanced. In addition, since the object detection system does not require a navigation system or the like for recognizing road conditions, the cost can be reduced and the vehicle can be mounted on more vehicles.

  The object detection system further includes a stop distance calculation unit that calculates a stoppable distance of the object based on the relative speed of the object, and the collision warning determination unit is calculated by the stop distance calculation unit. It is also preferable to determine that there is a possibility of collision of the object when the stoppable distance is greater than or equal to the distance of the object stored in the storage unit. The stoppable distance here preferably includes at least the sum of the free running distance and the braking distance.

  By taking into account the possible stop distance of the object, it is possible to determine the necessity of the alarm with higher accuracy.

  In the object detection system, when the speed of the vehicle is equal to or lower than a first determination value, or when the speed of the vehicle is equal to or lower than a second determination value greater than the first determination value and a winker operation is performed. It is also preferable to further include a system on / off determination unit that enables the object detection operation. Here, the “first determination value” is an extremely low speed (for example, 5 km / hour), and the “second determination value” is a relatively low speed (for example, 20 km / hour).

  Thereby, the object detection operation can be executed only when the necessity is higher, such as when the host vehicle is located at an intersection or a junction. Therefore, it is possible to reduce the power consumption of the system and avoid the output of an alarm in a scene where the necessity is low.

It is a block diagram which shows the structure of the object detection system for vehicles of one Embodiment. It is a figure for demonstrating the attachment position and detection range of an object detection sensor. It is a flowchart which shows operation | movement of an object detection system.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of an object detection system for a vehicle according to an embodiment. The object detection system shown in FIG. 1 includes an object detection sensor 1 mounted in front of the host vehicle, a control unit 2 that controls the overall operation of the object detection system, and voice (or light, based on commands from the control unit 2). And an alarm device 3 that gives an alarm by a driver to the driver.

  The object detection sensor 1 includes the presence of an object that may collide with the host vehicle, specifically, a vehicle such as a two-wheel or four-wheel vehicle, a bicycle, a person (hereinafter referred to as “target object”), and the target object. For detecting the distance to the host vehicle, laser radar, millimeter wave radar, optical sensor (TOF method), and the like can be used.

  FIG. 2 is a diagram for explaining an attachment position and a detection range of the object detection sensor 1. As shown in a schematic plan view in FIG. 2 (A), the object detection sensor 1 is located at an appropriate front position (for example, a fender, a bumper, a headlight, etc.) so that the side of the host vehicle 50 can be detected. Attached to. In the illustrated example, it is attached only to the front right side of the host vehicle 50, but may be attached to both the left and right sides of the host vehicle 50. In the case of mounting to only one of the vehicles, if the vehicle is determined to be left-hand traffic as in Japan, the vehicle 50 can be detected so that the target object can be detected from the right side of the vehicle 50. The object detection sensor 1 is attached to the front right side. In addition, what is necessary is just to set it as the reverse attachment position when the vehicle is determined as right-hand traffic. Further, as shown in FIG. 2B, the detection range of the object detection sensor 1 is from an orthogonal direction to an obliquely forward direction with respect to the front-rear direction of the host vehicle 50 so as to correspond to various intersections and junctions. A relatively wide range is set. Further, the detection distance of the object detection sensor 1 is preferably set to a relatively far distance in consideration of the case where the target object 51 such as another vehicle is moving at a high speed. The distance (for example, about 80 meters) is set so that the number of target objects to be detected is reduced to some extent so that the processing time does not become too long because the number of target objects to be detected becomes excessive.

  Returning to FIG. 1 again, the control unit 2 includes a distance / speed detection unit 11, a distance / speed information storage unit 12, a stop distance calculation unit 13, a collision warning determination unit 14, and a system ON / OFF determination unit 15. ing. The control unit 2 is realized by executing a predetermined operation program in a computer system including, for example, a CPU, a ROM, a RAM, a nonvolatile memory, and the like.

  The distance / speed detection unit 11 detects the distance and relative speed between a target object such as another vehicle approaching the host vehicle and the host vehicle based on the output from the object detection sensor 1. When there are a plurality of target objects, the distance and the relative speed are detected individually.

  The distance / speed information storage unit 12 stores the distance and relative speed of each target object detected by the distance / speed detection unit 11.

  The stop distance calculation unit 13 calculates a stop distance required when each target object tries to stop based on the relative speed of each target object stored in the distance / speed information storage unit 12. The method for calculating the stop distance will be described in detail later.

  The collision warning determination unit 14 determines the possibility of a collision between each target object and the host vehicle based on the calculation result of the stop distance by the stop distance calculation unit 13 and the distance of each target object. That is, the collision warning determination unit 14 determines the necessity of warning. When it is determined that an alarm is necessary, the collision alarm determination unit 14 supplies a predetermined alarm output command to the alarm device 3.

  The system ON / OFF determination unit 15 is a situation in which an object detection operation should be executed based on the state of the ignition switch (IGN signal), the speed of the host vehicle (vehicle speed signal), and the state of the winker switch (winker operation signal). It is determined whether or not.

  The object detection system of the present embodiment has such a configuration, and the operation thereof will be described in detail along the flowchart shown in FIG.

  The system ON / OFF determination unit 15 determines whether or not the ignition switch (IGN) is in the on state based on the IGN signal obtained from the host vehicle (step S10).

  When the ignition switch is on (step S10; YES), the system on / off determination unit 15 determines that the vehicle speed of the host vehicle is equal to or lower than the first determination value V1 based on the vehicle speed signal obtained from the host vehicle. It is determined whether or not there is (step S11). Here, “V1” is set at a relatively low speed, for example, 5 km / hour.

  When the vehicle speed is not less than or equal to the first determination value V1 (step S11; NO), the system ON / OFF determination unit 15 determines whether or not the vehicle speed of the host vehicle is less than or equal to the second determination value V2. (Step S12). Here, “V2” is set at a speed relatively higher than V1 described above, for example, 20 km / hour.

  When the vehicle speed is equal to or lower than the second determination value V2, the system ON / OFF determination unit 15 is in a state (TRN ON) in which the winker operation is performed based on the winker operation signal obtained from the host vehicle. Whether or not (step S13). That is, in this step, it is determined whether or not the own vehicle is located at an intersection or the like and is in a state of making a right turn or a left turn.

  If a negative determination (NO) is made in any of Step S10, Step S12, or Step S13 described above, that is, either the ignition switch is in an off state, the vehicle speed is not lower than V2, or the blinker operation is not performed In this case, since it is not necessary to operate the object detection system, the system ON / OFF determination unit 15 turns the system off (step S14). That is, no alarm is given (alarm OFF).

  On the other hand, when an affirmative determination (YES) is made in any of Step S11 and Step S13 described above, that is, when the vehicle speed is V1 or less, or when the vehicle speed is V2 or less and the blinker operation is performed. It is estimated that the vehicle is located at an intersection or the like. In this case, the system ON / OFF determination unit 15 determines that the object detection system needs to be operated, and turns on the system (step S15).

  In steps S10 to S15, the ignition is on (condition 1), the vehicle speed is equal to or lower than the first determination value V1 (condition 2), and the vehicle speed is equal to or lower than the second determination value V2. (Condition 3) When the winker operation is performed (Condition 4), (1) When the conditions 1 and 2 are satisfied, or (2) When the conditions 1, 3 and 4 are satisfied, the object detection system Turn on. According to this determination condition, when changing lanes while traveling at a low speed, the situation suitable for the condition for turning on the system other than the approach to the intersection can be considered when the vehicle is parked at a traffic light or parked. In these situations, it is difficult to assume a collision with another vehicle from the side of the host vehicle. However, in this situation, the object detection system is turned on, and even if an alarm is issued, it helps the driver to drive. I think there is no problem in system operation. That is, it is not misinformation.

  When the object detection system is turned on, the distance / speed detection unit 11 sets an initial value of a variable n indicating the number of target objects to 0 (step S16), and then turns on the object detection sensor 1 to detect the object. Based on the output from the sensor 1, the number of target objects is substituted into the variable n (step S17).

  Next, the distance / speed detection unit 11 detects information about all the target objects, and stores each distance and relative speed in the distance / speed information storage unit 12 (step S18). Here, Xn represents the distance of the nth target object from the host vehicle, and Vn represents the relative speed of the nth target object.

  Next, the stop distance calculation unit 13 determines whether or not the value of the variable n is 0 (step S19). When the variable n is 0 (step S19; YES), it means that the target object does not exist, so the collision warning determination unit 14 determines that the warning is not necessary and does not execute the warning (step S20). . In this case, the process returns to step S10 described above, and the subsequent processing is repeated.

  On the other hand, when the value of the variable n is not 0 (step S19; NO), the stop distance calculation unit 13 is based on the relative speed of each target object stored in the distance / speed information storage unit 12, and the nth It is determined whether or not the target object is approaching the host vehicle (step S21). For example, the approach of the target object can be determined on the basis of whether or not the relative speed of the nth target object is greater than zero.

When the nth target object is approaching the host vehicle (step S21; YES), the stop distance calculation unit 13 calculates the stoppable distance of the nth target object (step S22). Specifically, the stoppable distance D can be calculated as follows, for example, based on the relative speed Vn (m / s) of the nth target object.
D = D1 + D2 × α
here,
Free running distance D1 = Vn × 0.75
Braking distance D2 = Vn ² /(2×9.8×μ)
Safety distance α: Distance to the vehicle when stopped (for example, 5m)
Friction coefficient μ ・ ・ ・ Value according to road surface condition (for example, 0.45; wet asphalt)

  When the stoppable distance D of the nth target object is calculated, the collision warning determination unit 14 determines whether or not the stoppable distance D is equal to or greater than the distance Xn of the nth target object (step S23). .

  When the stoppable distance D is equal to or longer than the distance Xn (step S23; YES), the collision warning determination unit 14 determines that the nth target object may collide with the host vehicle, and outputs a warning output command. Is output to the alarm device 3 (step S24). Thereby, a warning is given to the driver from the warning device 3 by an appropriate method such as voice or image. When the alarm is executed, it is not necessary to execute the process for the remaining object, so the process returns to step S10 described above and the subsequent processes are repeated.

  On the other hand, when the stoppable distance D is not equal to or longer than the distance Xn (step S23; NO), the collision warning determination unit 14 determines that there is no possibility that the nth target object will collide with the host vehicle, and outputs a warning. Without outputting an instruction, (n-1) is substituted for variable n (step S25). Thereafter, the process returns to step S19, and the collision determination process for the remaining target object is repeated.

  As described above, the object detection system according to the present embodiment can detect all target objects (for example, vehicles, bicycles, humans, etc.) that exist on the side of the host vehicle without distinguishing between two wheels, four wheels, and the like. It can be. In addition, since the necessity of warning is determined in consideration of the speed and relative distance of the target object, for example, there is a need for warning when there is an object that is far away from the host vehicle but has a large relative speed. On the contrary, if the object is close to the host vehicle but the relative speed is 0 or a low-speed object, it is determined that there is no need for the alarm. Thereby, the detection range can be extended to a far distance while avoiding the alarm being output more than necessary. Furthermore, since a series of processes until the determination of the presence or absence of an alarm is simplified, the processing time can be shortened. As described above, the effect of preventing a collision with another vehicle or the like can be enhanced.

  In addition, since the object detection system of this embodiment does not require a navigation system or the like for recognizing road information, the cost can be reduced and the vehicle can be mounted on more vehicles. is there.

  Further, according to the object detection system of the present embodiment, it is possible to more accurately determine the necessity of an alarm since the stoppable distance of the target object is taken into account.

  In addition, this invention is not limited to the content of embodiment mentioned above, In the range of the summary of this invention, it can change and implement variously.

  For example, in the above-described embodiment, the stoppable distance of the target object approaching the host vehicle is calculated, and the presence or absence of the alarm is determined based on the distance between the target object and the target object, but the alarm is based only on the relative speed of the target object. You may determine the presence or absence of. In this case, in place of step 22 described above, a step is executed in which the collision warning determination unit 14 determines whether or not the relative speed of the target object exceeds a reference value (for example, 80 km / hour). The next step S23 may be omitted and alarm output may be executed. Alternatively, the necessity of the alarm may be determined by previously making a table of the relationship between the relative speed of the target object that is considered to require an alarm and the distance between the target objects, and referring to the table.

  Further, in the above-described embodiment, the friction coefficient μ of the road surface is used to calculate the stoppable distance of the target object, and it is assumed that this value is set in advance. May be set variably. For example, if a road surface sensor is provided in the host vehicle, the value of the friction coefficient μ can be variably set based on the output of the road surface sensor. As a result, it is possible to more accurately determine the presence or absence of an alarm in response to a change in the external environment.

1: Object detection sensor 2: Control unit 3: Alarm device 11: Distance / speed detection unit 12: Distance / speed information storage unit 13: Stop distance calculation unit 14: Collision alarm determination unit 15: System ON / OFF determination unit 50: Own vehicle 51: target object

Claims (4)

An object detection system for detecting an object that may collide with a vehicle,
An object detection sensor that is provided in front of the vehicle and detects a distance between an object present on a side of the vehicle and the vehicle;
Based on an output from the object detection sensor, a distance between the object and the vehicle is acquired, and a distance / speed detection unit that detects a relative speed of the object;
A distance / speed information storage section for storing the distance and the relative speed of the object detected by the distance / speed detection section;
A collision warning determination unit for determining the possibility of collision of the object based on the distance and the relative speed of the object;
An alarm device that outputs a predetermined alarm when the collision alarm determination unit determines that there is a possibility of collision of the object;
Including an object detection system. A stop distance calculating unit that calculates a stop possible distance of the object based on the relative speed of the object;
The collision warning determination unit determines that there is a possibility of collision of the object when the stoppable distance calculated by the stop distance calculation unit is equal to or greater than the distance of the object stored in the storage unit. The object detection system according to claim 1.   The object detection system according to claim 1, wherein the stoppable distance includes at least a sum of an idle running distance and a braking distance.   The object detection operation is effective when the vehicle speed is equal to or lower than the first determination value, or when the vehicle speed is equal to or lower than the second determination value greater than the first determination value and the winker operation is performed. The object detection system according to any one of claims 1 to 3, further comprising a system on / off determination unit.

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