Vehicle obstacle detection device

Abstract

This invention provides a vehicle obstacle detection device that can easily eliminate the occurrence of unnecessary alarms in long vehicles simply by setting the permissible detection range. [Solution] The detection range defining unit RD within the collision possibility determination unit CD defines an acceptable detection range AR behind the dead zone region DZ, which is determined by the detection ranges of multiple rear ultrasonic sensors A to D, when the vehicle is moving backward, and where detection of obstacles cannot be accurately performed. The acceptable detection range AR is defined as the range located behind the dead zone region DZ and enclosed by a pair of virtual extension lines VL1 and VL2 that extend backward along both sides of the vehicle.

Description

Technical Field

[0001] The present invention provides an obstacle detection device for a vehicle to prevent a part of the vehicle from colliding with an obstacle around the rear of the vehicle when parking the vehicle.

Background Art

[0002] FIG. 4 of Japanese Patent Application Laid-Open No. 11-110697 (Patent Document 1) discloses a display example of a display screen of an obstacle detection device for a vehicle, which includes a plurality of obstacle detection sensors for detecting obstacles in front of and behind the vehicle, and an obstacle distance information display means for displaying a graphic image indicating distance information regarding the distance between the obstacle detected by the plurality of obstacle detection sensors and the vehicle on the display screen. In this conventional obstacle detection device for a vehicle, as a graphic image displayed on the display screen, a vehicle image indicating the vehicle and information regarding the distance between the obstacle detection sensor and the obstacle and the detection direction of the obstacle detection sensor, which are displayed around the vehicle image, are displayed using an image arranged according to the number of a plurality of display segments arranged starting from the vehicle image and the parallel arrangement direction. FIGS. 5 and 6 show that the display screen includes a numerical display section for numerically displaying the distance to the obstacle based on the distance information output by the obstacle detection sensor for detecting the distance to the obstacle, and a step display section adjacent to the numerical display section. Further, in this conventional device, when the obstacle detection sensor detects an obstacle and the distance becomes less than 60 centimeters, a buzzer sounds to warn the driver.

[0003] FIG. 9 of Japanese Patent No. 3147541 (Patent Document 2) discloses a principle of specifying the position of an obstacle by receiving a light projection beam from one ultrasonic sensor with another ultrasonic sensor and using a plurality of ultrasonic sensors. In the invention of this publication, the probability of the presence of an obstacle in a plurality of predetermined regions is obtained, and the possibility of collision with the obstacle is determined based on the probability value.

[0004] Furthermore, the invention described in Japanese Patent Publication No. 7192600 (Patent Document 3) uses robust estimation to find an approximate line representing the location of an obstacle, and then uses this approximate line to calculate an approximate line representing the location of an obstacle, thereby improving the accuracy of determining the possibility of collision with an obstacle. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-110697 [Patent Document 2] Patent No. 3147541 [Patent Document 3] Patent No. 7192600 [Overview of the project] [Problems that the invention aims to solve]

[0006] Vehicle length is 7 myo For long vehicles such as medium-sized buses and large trucks, the range over which the vehicle backs up is also longer. Therefore, for example, when attempting to park two long vehicles next to each other, even when backing up in a straight line, the other vehicle may be recognized as an obstacle, triggering excessive warnings, which may cause the driver to temporarily disable the vehicle's obstacle detection system. While advanced calculations, as described in Patent Documents 2 and 3, may improve the accuracy of collision detection even for long vehicles, this is not easily implemented.

[0007] The object of the present invention is to provide a vehicle obstacle detection device that can easily eliminate the generation of unnecessary alarms that occur in vehicles with a vehicle length longer than 7m. [Means for solving the problem]

[0008] The vehicle obstacle detection device of the present invention is for vehicles with a length of 7 myoThe present invention includes a plurality of rear ultrasonic sensors, each having a fan-shaped detection range, positioned at intervals in the width direction of the vehicle at the rear of a long vehicle, and detecting the presence of obstacles by receiving ultrasonic waves reflected by obstacles; a detection range defining unit that defines a predetermined permissible detection range relative to the rear of the vehicle; a collision possibility determination unit that determines the possibility of collision between an obstacle and the vehicle based on the output of the plurality of rear ultrasonic sensors, depending on whether an obstacle is present within the permissible detection range; and a warning display unit that displays the determination result of the collision possibility determination unit to the driver as a warning. In this invention, the permissible detection range is defined behind the dead zone region where obstacle detection, determined by the detection ranges of the plurality of rear ultrasonic sensors, cannot be accurately performed when the vehicle moves backward. This permissible detection range is defined as the range behind the dead zone region and enclosed by a pair of virtual extension lines that extend backward along both sides of the vehicle. With the permissible detection range defined in this way, when turning in reverse, if a part of an adjacent vehicle enters the permissible detection range of the rear area of ​​the vehicle, a warning display is issued. Therefore, collisions can be prevented when turning in reverse. Furthermore, after the turn is completed, since the movement is linear, even if the distance between adjacent vehicles is short, the possibility of any part of an adjacent vehicle entering the permissible detection range, which is within the vehicle's width dimension, is low. Therefore, according to the present invention, the generation of unnecessary alarms that occur in vehicles with long vehicle lengths can be easily eliminated simply by setting the permissible detection range.

[0009] When using ultrasonic sensors with a fan-shaped detection range, a dead zone inevitably forms between the fan-shaped detection ranges of two adjacent ultrasonic sensors. Therefore, conventionally, it has been impossible to avoid the occurrence of a dead zone when using ultrasonic sensors. It is therefore preferable to determine the number and installation interval of multiple rear ultrasonic sensors so that the maximum dimension of the dead zone measured from the rear end of the vehicle toward the rear is the desired dimension. In this way, the dead zone formed between the fan-shaped detection ranges of two adjacent ultrasonic sensors becomes smaller. While increasing the number of ultrasonic sensors used and reducing the installation interval can narrow the dead zone, the cost of the device increases. Therefore, in practical terms, by determining the number of ultrasonic sensors and the installation interval of multiple ultrasonic sensors in the vehicle width direction according to the maximum dimension of the dead zone, the occurrence of collisions in long vehicles can be reduced inexpensively and significantly.

[0010] The collision possibility determination unit is configured to detect multiple rear direction Based on the output of the side ultrasonic sensor, if it is determined that there may be an obstacle in the dead zone, the system may output a signal to the warning display unit that will emit a different warning display, distinct from the warning display issued when an obstacle is detected within the permissible detection range. In this way, the driver who recognizes the different warning display can perform the reversing maneuver while paying attention to the different warning display as a reference.

[0011] The warning display unit may be configured to display a graphic image on the display screen as a warning display, which shows distance information regarding the distance between the vehicle and an obstacle detected by multiple rear ultrasonic sensors. In this case, for example, the graphic image may be a vehicle image showing the vehicle and a graphic image displayed around the vehicle image. Posterior ultrasoundThe information regarding the distance between the sensor and the obstacle, as well as the detection direction of the rear ultrasonic sensor, may be displayed as an image using the number and orientation of multiple display segments arranged starting from the vehicle image. In this case, it is preferable that the warning display unit has a function to supplement the display of distance information by changing the color of the multiple display segments in accordance with the change in distance. By changing the color of the multiple display segments in accordance with the change in distance in this way, it becomes possible to alert the driver to the change in distance not only by the number of display segments but also by the change in color.

[0012] The graphic image used in the warning display unit may be configured to display information regarding the detection direction of multiple rear ultrasonic sensors and the distance between the vehicle and the obstacle, based on the position of the obstacle image relative to the vehicle image. In this case as well, it is preferable that the warning display unit has a function to supplement the display of distance information by changing the color of the obstacle image in accordance with the change in distance. By changing the color of the obstacle image in accordance with the change in distance, the driver can also be alerted to the change in distance by the change in color.

[0013] The graphic image may include an image indicating the presence of a dead zone. This would increase the driver's awareness of the warning display by informing them of the presence of the dead zone. [Brief explanation of the drawing]

[0014] [Figure 1] This is a block diagram showing the schematic configuration of the vehicle obstacle detection device according to this embodiment. [Figure 2] Figures (A) through (D) show examples of graphic images of warning signs that are displayed on the screen. [Figure 3] This diagram is used to explain the principle of setting the acceptable detection range using two rear ultrasonic sensors. [Figure 4] This diagram shows the algorithm of a program used when a computer is used to determine the presence of an obstacle using the outputs of two rear-facing ultrasonic sensors. [Figure 5] FIG. 1 is a diagram used to explain an example of a method for measuring distance with an ultrasonic sensor. [Figure 6] FIG. 2 is a diagram used to explain an example of a method for calculating coordinate values from the output of an ultrasonic sensor. [Figure 7] FIG. 3 is a diagram used to explain a method for reducing a dead zone. [Figure 8] FIG. 4 is a diagram showing another example of a graphic image indicating distance information regarding the distance between an obstacle and a vehicle. [Figure 9] FIG. 5 is a diagram showing an example of a display of a dead zone. BEST MODE FOR CARRYING OUT THE INVENTION

[0015] Hereinafter, embodiments of the vehicle obstacle detection device of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a vehicle obstacle detection device VD according to an embodiment, including four rear ultrasonic sensors A to D for detecting obstacles on the rear side of a vehicle having a vehicle length longer than 7 m (medium-sized bus or more), a plurality of front ultrasonic sensors N for detecting obstacles on the front side of the vehicle, a collision possibility determination unit CD provided with a detection range regulation unit RD, and an alarm display unit AD provided with a display screen DS. FIG. 2(A) shows a full display state of a warning display, (B) shows a display on the display screen when the vehicle is traveling forward at high speed, (C) shows a warning display when the vehicle is moving forward at low speed, and (D) shows a warning display when the vehicle is moving backward at low speed. In FIG. 2, V is a vehicle image, and the vehicle image includes a front warning display FI composed of nine display segments C and a rear warning display BI composed of three display segments C1 to C3.

[0016] The front - side warning display FI is composed of nine segments C0 displayed on the front side of the vehicle image V. The three display segments C0 arranged from the left - hand corner of the vehicle image V outward indicate the detection direction and detection result of the front - side ultrasonic sensor N provided at the left - hand corner of the vehicle. The three display segments C0 arranged from the right - hand corner of the vehicle image V outward indicate the detection direction and detection result of the front - side ultrasonic sensor N provided at the right - hand corner of the vehicle. The three display segments C0 arranged from the front - center of the vehicle image V outward indicate the detection direction and detection result of the front - side ultrasonic sensor N provided at the front - center of the vehicle. The number and arrangement positions of the plurality of front - side ultrasonic sensors N are arbitrary. Since the front - side warning display FI is not the subject of the present invention, a detailed description is omitted. [[ID=]] [[ID=]]

[0017] [[ID=]] The rear - side warning display BI is composed of three display segments C1 - C3 arranged from the rear - center of the vehicle image V outward. The display by the three display segments C1 - C3 indicates the detection direction and detection result of the rear - side ultrasonic sensors A to D provided at the rear of the vehicle. The three display segments C1 - C3 show the discrimination result of whether there is an obstacle within the allowable detection range determined by the outputs of the four rear - side ultrasonic sensors A to D and the allowable regulation range described later defined by the detection range regulation unit RD in FIG. 1 by changing the display mode of the display segments C1 - C3. Specifically, among the three display segments C1 - C3 shown in FIG. 2(D), the third display segment C3 has a different display mode from the other two display segments C1 and C2 in order to indicate that there is an obstacle at the distance corresponding to the display segment C3 on the rear - side of the vehicle. The display mode of the display segments C1 to C3 can be changed by changing the color of the display segment or blinking the display segment.

[0018] [[ID=]] In this embodiment, the display mode of display segments C1 to C3 is changed by changing the color of the display segments to display a distance range that includes the distance from the rear end of the vehicle to an obstacle that is within a predetermined allowable range set backward from the rear end of the vehicle. As will be described later, in this embodiment, an allowable range is set behind the dead zone, which is a dead zone that always occurs when using an ultrasonic sensor and includes areas where obstacles can be detected and areas where they cannot be detected. In this embodiment, the allowable detection range is defined as the range behind the dead zone and enclosed by a pair of virtual extension lines that extend backward along both sides of the vehicle. In this embodiment, the position furthest from the rear end of the vehicle within the allowable detection range is assumed to be the maximum separation position, the position closest to the rear end of the vehicle is assumed to be the minimum separation position, and the positions that divide the space between the maximum separation position and the minimum separation position are assumed to be the first intermediate separation position and the second intermediate separation position. Under this assumption, if an obstacle is detected between the maximum separation position and the second intermediate separation position, display segment C3 lights up, for example, in green; if an obstacle is detected between the second intermediate separation position and the first intermediate separation position, display segments C3 and C2 light up, for example, in green; and if an obstacle is detected between the first intermediate separation position and the minimum separation position, display segments C1 to C3 all light up, for example, in yellow. Under this assumption, the area between the rear end of the vehicle and the minimum separation position becomes the dead zone. After display segments C1 to C3 light up in sequence, if it is detected that the vehicle has moved backward beyond the minimum separation position, display segments C1 to C3 all turn red and flash to indicate that the vehicle has entered the dead zone. Along with the change in the color of the display segments, the frequency of the warning sound may be shortened, and the warning sound may be set to maximum continuous tone at the same time as display segments C1 to C3 all turn red. In this warning display, the collision possibility determination unit CD has determined that an obstacle is in the dead zone. In other words, this state is multiple after directionBased on the output of at least one ultrasonic sensor of the side ultrasonic sensor, it can be determined that an obstacle may be in a dead zone, and that a separate warning display is issued from the warning display unit, which is distinguishable from the warning display issued when an obstacle is detected within the permissible detection range.

[0019] It goes without saying that other display modes and warning display methods can be used for the display segments and warning sound methods. In addition, the collision possibility determination unit CD can output an automatic stop alarm to forcibly stop the vehicle, indicating that the vehicle has entered a dead zone, and simultaneously output a forced stop signal to stop the vehicle.

[0020] Figure 3 is used to illustrate the principle of setting the allowable detection range AR using two rear ultrasonic sensors A and B. The two rear ultrasonic sensors A and B are located at a vehicle length of 7 myoThe two rear ultrasonic sensors A and B are positioned at the rear of the long vehicle, spaced apart in the width direction of the vehicle. As shown in Figure 3, the two rear ultrasonic sensors A and B each have a fan-shaped detection range DRa and DRb that detect the presence of an obstacle by receiving ultrasonic waves reflected by the obstacle. In this embodiment, the detection range defining unit RD defines the allowable detection range AR relative to the rear of the vehicle. The detection range defining unit RD defines the area at the rear of the vehicle that includes three dead zones NR where the fan-shaped detection ranges DRa and DRb of the two rear ultrasonic sensors A and B do not exist as a dead zone where obstacle detection cannot be accurately performed, and defines the allowable detection range AR as the area behind the dead zone DZ, sandwiched between a pair of virtual extension lines VL1 and VL2 that extend rearward along both sides of the vehicle. The distance between the pair of virtual extension lines VL1 and VL2 corresponds to the actual vehicle width. In the example shown in Figure 3, of the three obstacles OB1 to OB3, one obstacle OB1 is within the permissible detection range AR and is therefore selected as a target for detection by the collision possibility determination unit CD. However, the other two obstacles OB2 and OB3 are outside the permissible detection range AR and are therefore excluded from detection by the collision possibility determination unit CD. The collision possibility determination unit CD determines the possibility of a collision between an obstacle and a vehicle based on the output of two rear ultrasonic sensors A and B, depending on whether or not an obstacle is present within the permissible detection range AR. When using two rear ultrasonic sensors A and B, the distance between the obstacle and the ultrasonic sensor is measured using either a method in which the ultrasonic waves emitted by each rear ultrasonic sensor are reflected by the obstacle and received by each rear ultrasonic sensor, or a method in which the ultrasonic waves emitted by one rear ultrasonic sensor are received by the other rear ultrasonic sensor.

[0021] Figure 4 shows the algorithm of the program used when the collision possibility determination unit CD uses the outputs of two rear ultrasonic sensors A and B to determine the presence of an obstacle using a computer. In this algorithm, as shown in Figure 5, rear ultrasonic sensor A transmits and receives ultrasonic waves, and rear ultrasonic sensor B receives ultrasonic waves. In Figure 5, Ta is the time from step ST1 when the ultrasonic wave transmitted by rear ultrasonic sensor A is reflected by obstacle OB and received by rear ultrasonic sensor A as an echo, and Tb is the time from step ST1 when the ultrasonic wave transmitted by rear ultrasonic sensor A is received by rear ultrasonic sensor B as an echo. These echo reception times Ta and Tb are measured in step ST2. In step ST3, it is determined whether the measurement of the ultrasonic echo reception times Ta and Tb was successful. If the measurement of the echo reception times Ta and Tb was unsuccessful (i.e., there was no reflection from the obstacle), the process proceeds to step ST8, where it is determined that there is no obstacle. If the measurement of the echo reception times Ta and Tb was successful in step ST3, the process proceeds to step ST4. In step ST4, the distance La from the rear ultrasonic sensor A to the obstacle OB and the distance Lb from the rear ultrasonic sensor B to the obstacle OB are calculated in Figure 5. This calculation is performed using the following formula.

[0022]

number

[0023]

number

[0024] When using ultrasonic sensors with a fan-shaped detection range, as in this embodiment, a dead zone NR is inevitably formed between the fan-shaped detection ranges of two adjacent ultrasonic sensors. Therefore, as shown in Figure 7, by increasing the number of ultrasonic sensors from two to four rearward ultrasonic sensors and appropriately determining their installation intervals, it is possible to make the maximum dimension of the dead zone DZ, measured from the rear end of the vehicle toward the rear, a desired short dimension. This reduces the dead zone formed between the fan-shaped detection ranges of two adjacent ultrasonic sensors. While increasing the number of ultrasonic sensors used and reducing the installation intervals can narrow the dead zone DZ, it increases the cost of the device. Therefore, practically, by determining the number of ultrasonic sensors and the installation interval of the multiple ultrasonic sensors in the vehicle width direction according to the maximum dimension of the dead zone, the occurrence of collisions in long vehicles can be reduced inexpensively and significantly.

[0025] As shown in Figure 8, the warning display unit AD may be configured to display a graphic image showing distance information regarding the distance between the vehicle and an obstacle detected by multiple rear ultrasonic sensors, based on the detection direction of the multiple rear ultrasonic sensors and the position of the obstacle image OBI relative to the vehicle image. In this case as well, the warning display unit AD may have a function to supplement the display of distance information by changing the color of the obstacle image OBI in accordance with the change in distance. Changing the color of the obstacle image OBI in accordance with the change in distance allows the driver to be alerted to the change in distance by the change in color as well.

[0026] Furthermore, as shown in Figure 9, the graphic image may also include an image DZI indicating the presence of a dead zone. By doing so, it is possible to increase the driver's awareness of the warning display by informing them of the presence of a dead zone. [Industrial applicability]

[0027] According to the present invention, the occurrence of unnecessary alarms in vehicles with long vehicle lengths can be easily eliminated simply by setting the permissible detection range. [Explanation of Symbols]

[0028] A-D Rear ultrasonic sensors N Front ultrasonic sensor RD detection range definition unit CD collision possibility determination unit DS display screen AD alarm display section VD Vehicle Obstacle Detection System C0~C3 Display Segments

Claims

1. Multiple rear ultrasonic sensors, each having a fan-shaped detection range, are positioned at intervals in the width direction of the vehicle at the rear of a vehicle longer than 7m in length, and detect the presence of obstacles by receiving ultrasonic waves reflected by obstacles. Includes a detection range defining unit that defines a predetermined permissible detection range relative to the rear of the vehicle, and a collision possibility determination unit that determines the possibility of a collision between the obstacle and the vehicle based on the output of the plurality of rear ultrasonic sensors, depending on whether or not the obstacle is present within the permissible detection range. A vehicle obstacle detection device comprising a warning display unit that displays the determination result of the collision possibility determination unit to the driver as a warning, The allowable detection range is set behind the dead zone region where, when the vehicle moves backward, the detection of the obstacle, determined by the detection range of the plurality of rear ultrasonic sensors, cannot be accurately performed. The vehicle obstacle detection device is characterized in that the allowable detection range is defined as the range located behind the dead zone and enclosed by a pair of virtual extension lines extending rearward along both sides of the vehicle.

2. The obstacle detection device for a vehicle according to claim 1, wherein the number of the plurality of rear ultrasonic sensors and the spacing between the plurality of rear ultrasonic sensors in the width direction of the vehicle are determined according to the maximum dimension of the dead zone area measured from the rear end of the vehicle toward the rear.

3. The vehicle obstacle detection device according to claim 2, wherein when the collision possibility determination unit determines, based on the output of the plurality of rear ultrasonic sensors, that the obstacle may be in the dead zone area, it outputs a signal to the warning display unit to emit a different warning display that can be distinguished from the warning display emitted when it detects that the obstacle is in the allowable detection range.

4. The warning display unit is configured to display a graphic image on the display screen as the warning display, which shows distance information regarding the distance between the obstacle detected by the plurality of rear ultrasonic sensors and the vehicle. The graphic image is an image that displays a vehicle image representing the vehicle, and information regarding the distance between the rear ultrasonic sensor and the obstacle, and the detection direction of the rear ultrasonic sensor, which are displayed around the vehicle image, based on the number and arrangement direction of a plurality of display segments arranged starting from the vehicle image. The obstacle detection device for a vehicle according to claim 1, wherein the warning display unit has a function to supplement the display of distance information by changing the color of the plurality of display segments in accordance with the change in distance.

5. The warning display unit is configured to display a graphic image on the display screen as the warning display, which shows distance information regarding the distance between the obstacle detected by the plurality of rear ultrasonic sensors and the vehicle. The graphic image is configured to display information regarding the detection direction of the plurality of rear ultrasonic sensors and the distance between the vehicle and the obstacle, based on the position of the obstacle image relative to the vehicle image representing the vehicle. The vehicle obstacle detection device according to claim 1, wherein the warning display unit has a function to supplement the display of distance information by changing the color of the obstacle image in accordance with the change in distance.

6. The obstacle detection device for a vehicle according to claim 4 or 5, wherein the graphic image includes an image indicating the presence of the dead zone region.

Images