JPH11202051A - Object detector and traveling vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance detection accuracy of obstacle while reducing the width being occupied by an automatically guided vehicle during traveling by increasing the number of measurements for operating a mean value in a range approximately perpendicular to the radiating direction thereby making uniform the error width along a border lane in the direction perpendicular thereto. SOLUTION: The number of measurements for operating a mean value is increased as the angular range approaches just beside an automatically guided vehicle and the accuracy of mean value is enhanced. Error component in the direction perpendicular to the left and right border lines 37, 38 is decreased significantly in the range of the border lines 37, 38 just beside the vehicle. Width of a gray zone 41 in the direction perpendicular to the border lines 37, 38 is made uniform along the border lines 37, 38. Since the gray zone 41 is reduced just beside the vehicle, detection accuracy of obstacle is enhanced in the area 36 requiring measurement and the width being occupied by the vehicle can be reduced along the traveling route.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object detecting device for detecting an object by a laser radar or the like and a traveling vehicle equipped with the same, and more particularly, to extracting and detecting an object in a predetermined limited area. The present invention relates to an object detection device and a traveling vehicle equipped with the same.

[0002]

2. Description of the Related Art In Japanese Unexamined Patent Publication No. 9-26826, in an automatic guided vehicle equipped with a laser radar and traveling while detecting obstacles with the laser radar, objects outside the required occupation width along the traveling route are obstacles. Instead of detecting as an object, only an object within a necessary occupation width is accurately detected as an obstacle, thereby preventing unnecessary braking from being performed by an object that does not become an obstacle during traveling. In order to extract only objects within such a required occupation width as obstacles, a predetermined forward range from the automatic guided vehicle is set as the obstacle detection required area, and the laser is extended far enough to cover the obstacle detection required area. In addition to emitting light (39), objects in the area required for obstacle detection are searched and extracted from all objects detected by the reflected light.

[0003]

The distance measurement by the laser light includes an error in the radiation direction regardless of the radiation direction of the laser light. On the other hand, since the area required for obstacle detection is spread in a substantially rectangular shape in front of the automatic guided vehicle, the object located on the vertical side of the area required for obstacle detection (boundary line parallel to the traveling direction of the automatic guided vehicle) The error component in the direction perpendicular to the vertical side increases in the range just beside the automatic guided vehicle from the diagonally forward direction of the automatic guided vehicle, and the gray zone in which the distance to the object cannot be determined (see FIG. 2 described later). Described above) becomes non-uniform along the vertical side of the obstacle detection necessary area. This leads to an increase in the required occupation width of the automatic guided vehicle during traveling, which is disadvantageous.

An object of the present invention is to provide an object detection device which overcomes the above-mentioned problems and a traveling vehicle equipped with the same.

[0005]

An object detecting apparatus according to the present invention is provided.
According to (16), a radiation wave (39) is radiated, and an object (20) within a measurement required area (36) is extracted and detected based on the reflected wave. In this object detection device (16),
For the distance to (20), the average of the measured values in multiple measurements in the angle range direction shall be averaged, and the boundary (37, 38) of the measurement required area (36) will be the radiation of the radiated wave (39). In the range close to the direction perpendicular to the direction, increase the number of measurement values for calculating the average in the range close to the direction parallel to the radiation direction of the radiated wave (39), and add it to the boundaries (37, 38). The error width in the perpendicular direction is made uniform along the boundary (37, 38).

The radiation wave 39 includes infrared rays, ultrasonic waves, and radio waves in addition to laser light. The measurement required area (36) includes trapezoids and other shapes other than rectangles. The multiple measurements in the angular range direction are, for example, in the case of multiple distance measurements at the same angular position, and when sweeping the radiated wave (39) like a radar, each measured angular position is little by little. Different, but multiple measurements within a predetermined limited angle range. The area required for measurement (36) is the object detection device (1
Not only may 6) be mounted on a moving body such as an automatic guided vehicle (10) and change over time, but also may be stationary, such as at a level crossing.

Since the measured value up to the object (20) based on the reflected wave of the radiation wave (39) includes an error in the radiation direction of the radiation wave (39),
In the range where the boundary line (37, 38) of the measurement required area (36) is close to a right angle to the radiation direction of the radiation wave (39), , Border (37,38)
, The error component in the direction perpendicular to the direction increases. On the other hand, the error of the measured value up to the object (20) due to the reflected wave of the radiation wave (39) has a Gaussian distribution. Therefore, if the average of a plurality of measurement times is averaged and the number of measurement times is increased, the error of the measurement value decreases. Based on this, the required measurement area (3
In the range where the boundary line (37, 38) of (6) is close to the direction perpendicular to the radiation direction of the radiation wave (39), the average is calculated for the range close to parallel to the radiation direction of the radiation wave (39). By increasing the number of measurements to be performed, the final measured value up to the object (20) is closer to the direction perpendicular to the radiation direction of the radiation wave (39) than the radiation direction of the radiation wave (39). The range (37, 38) and the absolute error in the direction perpendicular to the boundary (37, 38) are uniform along the boundary (37, 38). The detection accuracy of the object (20) can be improved.

According to the object detection device (16) of the present invention, the radiation (39) is radiated while being swept, and the object (20) in the predetermined measurement required area (36) in the sweep direction is based on the reflected wave. ) Is extracted and detected. In this object detection device (16), the distance to the object (20) is determined by averaging the measured values at a plurality of angular positions following the sweep direction, and the boundary (37, 38) of the area (36) required for measurement. ) Is near perpendicular to the radiation direction of the radiation wave (39), increase the number of measurement angle positions for calculating the average over the range close to parallel to the radiation direction of the radiation wave (39). Then, the error width in the direction perpendicular to the boundary lines (37, 38) is made uniform along the boundary lines (37, 38).

In the case of the traveling vehicle (10), the sweep direction of the radiation wave (39) is generally horizontal left and right with respect to the traveling direction.
However, in the object detection device (16), the sweep direction of the radiation wave (39) is not limited to the horizontal direction in the left and right directions, but includes the vertical direction and the oblique horizontal direction.

At each of a plurality of angular positions following the sweep direction, the distance to the object (20) is measured. Area required for measurement
In the range where the boundary (37, 38) of (36) is almost perpendicular to the radiation direction of the radiated wave (39), the measured value is By increasing the number of measurement angle positions for calculating the average, the accuracy of the measurement value in a range close to a right angle to the radiation direction of the radiation wave (39) is increased, and as a result, the boundary of the measurement required area (36) is increased. Line (37,
The absolute error in the direction perpendicular to the direction (38) is made uniform along the boundary lines (37, 38), and the detection accuracy of the object (20) in the measurement required area (36) can be improved.

According to the object detection device (16) of the present invention, when the boundary (37, 38) of the measurement required area (36) is close to a right angle to the radiation direction of the radiation wave (39), the object ( The angular interval of the angular position for measuring 20) is made dense in a range near parallel to the radiation direction of the radiation wave (39).

In an angle range in which the number of measurements needs to be increased in order to reduce the relative error of the measured value, the number of measurement angle positions within a predetermined angle range increases by reducing the interval between the measurement angle positions. In this way, the minimum required measurement angle position can be set without unnecessarily increasing the entire measurement angle position.

According to the object detecting device (16) of the present invention, the time interval for measuring the distance to the object (20) is fixed, and the angle range in which the angular intervals of the angular positions are dense is set to be sparse. And lower the sweep speed.

For example, in a laser radar (16), a mirror reciprocates to rotate and sweep laser light, and the sweep speed is increased or decreased by controlling the rotation speed of the mirror.

According to the object detection device (16) of the present invention, the sweep speed is constant, and the distance to the object (20) is smaller in the range where the angular interval between the measurement angle positions is denser than in the range where the angle interval is sparse. Shorten the time interval for measurement.

For example, in the laser radar (16), the measurement time interval can be controlled by changing the blinking frequency of the laser light while keeping the rotation speed of the mirror constant.

A traveling vehicle (10) according to the present invention is equipped with the above-mentioned object detection device (16), and travels with the required occupation width in the traveling being the left and right width of the measurement required area (36).

The traveling vehicle (10) sets a predetermined range including the traveling route (14) as an area required for measurement (36) by the object detecting device (16), and sets the object (20) in the area required for measurement (36). By extracting and detecting the vehicle safety, traveling safety can be obtained. Since the error in the direction perpendicular to the boundary lines (37, 38) of the measurement required area (36) is made uniform by the object detection device (16), the required occupation width for traveling can be reduced.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of an obstacle detection method of the automatic guided vehicle 10. The automatic guided vehicle 10 has a built-in motor for driving the tires 12 and drives and / or drives four tires 12.
Alternatively, the vehicle travels along a predetermined traveling route 14 in a room such as a factory or a warehouse while being steered.
For example, magnets are buried at appropriate intervals in the traveling route 14, and the automatic guided vehicle 10 detects a magnetic field from the magnet,
A guidance system that detects the traveling route 14 is employed.
The laser radar 16 is provided at the front of the automatic guided vehicle 10, and even at the curved section entrance point of the traveling route 14, to ensure the detection of the obstacle 20 sufficiently ahead from the curved section exit point,
It has a detection range 18 of, for example, 60 ° left and right with respect to the traveling route 14, and as a result, a wide range of obstacles 20 to be moved is detected. The obstacles 20 detected by the laser radar 16 include not only people but also machines, structures, and the like. Instead of the laser radar 16, a sweep type infrared, ultrasonic, or radio wave radar, an array of a plurality of directional radars that can search a predetermined angle range as a whole in different directions, or the like can be used. In the traveling route 14, the predetermined destination range from the local point of the automatic guided vehicle 10 is, in order from the farthest to immediately before, the danger level 1 area 2
2, the danger level 2 area 24, the danger level 3 area 26, and the danger level 4 area 28.

The laser radar 16 irradiates a laser beam toward the front, that is, a direction to move from now on, receives the reflected light, and detects the detection range of the laser radar 16 based on the reflected light.
All obstacles 20 existing at 18 are detected. Next, from the detected obstacles 20, the automatic guided vehicle on the traveling route 14
10 width direction route occupation range (width direction occupation range is
In FIG. 1, it corresponds to the inner range of two broken lines extending parallel to both sides of the solid line of the traveling route 14. ) Obstacles
Extract only 20. In the storage device of the automatic guided vehicle 10, the route data of the traveling route 14 is stored in advance, and based on the stored data, the width direction route of the automatic guided vehicle 10 on the traveling route 14 from a local point to a predetermined destination. The occupation range can be detected directly or indirectly by calculation. Thus, in FIG. 1, the obstacles 20 existing in the danger level 2 area 24 are extracted, but the obstacles 20 existing outside the outer boundary line of the danger level 3 area 26 are not extracted.
Excluded. On the other hand, with regard to the traveling route 14 to be moved, the dangerous level 1 area 22, the dangerous level 2 area 24,
It is divided into a danger level 3 area 26 and a danger level 4 area 28. The path length, which is a factor of the risk level classification, is related to the current traveling speed of the automatic guided vehicle 10 and the gradient of the traveling route 14. The higher the traveling speed, the shorter the time until the collision. Therefore, the length to the distant point of each danger level and the length of each danger level itself in the traveling route 14 are increased. Further, if the uphill angle of the traveling route 14 from now on is assumed to be positive, the stopping distance for the same braking force increases as the slope angle decreases, that is, as the downhill becomes steeper. The height increases as the gradient angle decreases.

Next, it is determined in which danger level area the extracted obstacle 20 exists. And danger level 1
When the obstacle 20 exists in the area 22, a warning light 50 such as a patrol lamp (red warning flashing lamp) as a first-stage warning is turned on. When the obstacle 20 exists in the danger level 2 area 24, In addition to the operation of the warning light 50, the siren 52 is sounded as a second stage alarm. When the obstacle 20 exists in the danger level 3 area 26, the unmanned operation is performed in addition to the operation of the warning light 50 and the siren 52. When the brake 54 of the transport vehicle 10 is operated appropriately, the unmanned transport vehicle 10 is decelerated (to the extent that it does not stop) as the first stage traveling speed control, and the obstacle 20 exists in the danger level 4 area 28 Operates the emergency stop of the automatic guided vehicle 10 as the second-stage running speed control while operating the warning light 50 and the siren 52 by operating the brake 54 to the maximum.

FIG. 2 shows a gray zone 41 in a predetermined measurement required area 36 in the case of normal processing by measurement by the laser radar 16. In this case, the measurement required area 36
Is a rectangular area that spreads forward just before the laser radar 16. In FIG. 1, the unmanned guided vehicle 10 turns around the curved portion of the traveling route 14 and travels along the straight portion of the traveling route 14. For example, it corresponds to the danger level 4 area 28 immediately before the automatic guided vehicle 10. Left vertical border
37 and the right vertical boundary line 38 extend a predetermined distance forward along the traveling route 14 in parallel. Laser light 39 is swept in direction 40
While being swept, the light is radiated in each angular direction for each angular position at equal angular intervals. The distance detected from each reflected light includes an absolute error L. In FIG. 1, the sweep angle range of the laser light 39 has been described as being, for example, 60 ° left and right around the traveling route 14, but in FIG.
°. Assuming that there is an object on the left vertical boundary 37 and the right vertical boundary 38, the absolute error L is the radiation direction of the laser light 39 based on the intersection of the laser light 39 and the left vertical boundary 37 or the right vertical boundary 38. Therefore, the gray zone 41 as a range in which the position of the object cannot be further specified on the left vertical boundary line 37 or the right vertical boundary line 38 is shown in FIG. That is, the width of the gray zone 41 in the direction perpendicular to the left vertical border 37 and the right vertical border 38 is the left-right component of each L,
It spreads in the 16 sideways range and narrows in the diagonally forward range. If the detected object is in the gray zone 41, it means that it is unknown whether the object is inside or outside the left vertical border 37 or the right vertical border 38. It is necessary to widen the width occupied range of the carrier 10 in the width direction.

FIG. 3 shows a situation in which the required measurement area 36 is divided into angular ranges around the laser radar 16. In this case, the measurement necessary area 36 is symmetrically divided into a plurality of angle ranges z1, z2, z3, z4, z5, and z6. In the laser radar 16, the sweep is performed by the reciprocating rotation of the mirror, the light source of the laser light 39 blinks at a predetermined frequency, and the laser light 39 is emitted at the time of lighting, so that the distance measurement angle position is in the sweep direction. Are arranged at equal angular intervals. The distance to the obstacle 20 is
The average of the measured values at a plurality of distance measurement angle positions continuously arranged at equal angular intervals in the sweep direction of the laser light is used. Then, the number of distance measurement angle positions to be averaged is set for each of the angle ranges z1, z2, z3, z4, z5, and z6, and n and 2n in the angle ranges z1, z2, z3, z4, z5, and z6, respectively. , 4n, 16n, and 32n (where n is an integer). Thus, the angle ranges z1, z2, z3, z4, z5, z6 approaching right beside the automatic guided vehicle 10
As the number of measurements for averaging increases, the accuracy of the measured value as an average value increases. Regarding the angle range z1, although the horizontal side as the boundary line of the measurement necessary area 36 is perpendicular to the laser beam 39, the distance measurement angle position for error reduction is not reduced. Automatic guided vehicle
Since there are 10 approach directions, it is necessary to determine that the obstacle is 20 irrespective of the distance to the object, and improving the measurement accuracy is not very significant. Therefore, for the distance measurement of the obstacle 20 ahead of the front side of the measurement required area 36,
Instead of taking the average of the measured values, the measured value of one measurement may be adopted as the final measured value as in the related art.

FIG. 4 shows the state of the gray zone 41 as a result of correction of the measured value by the average value. As shown in FIG. 3, as the angle range approaches the side of the automatic guided vehicle 10, the number of measurements for taking the average increases, and the accuracy of the measured value as the average value increases. As a result, the left vertical boundary line 37 and the right vertical boundary line
The error component in the direction perpendicular to 38 is remarkably reduced in the range of the left vertical boundary line 37 and the right vertical boundary line 38 which are close to the side of the automatic guided vehicle 10, and the gray zone 41 is shown in FIGS. Thus, the width of the gray zone 41 in the direction perpendicular to the left vertical border 37 and the right vertical border 38 is made uniform along the left vertical border 37 and the right vertical border 38. In this way, the gray zone 41 is also reduced immediately beside the automatic guided vehicle 10, so that the obstacle
The detection accuracy of 20 has been improved, and automatic guided vehicles along running route 14
The traveling occupation width of 10 can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an obstacle detection method for an automatic guided vehicle.

FIG. 2 is a diagram showing a gray zone in a case where normal processing is performed by laser radar measurement in a predetermined measurement required area.

FIG. 3 is a diagram showing a situation in which a measurement required area is divided into angle ranges around a laser radar.

FIG. 4 is a diagram showing a state of a gray zone as a result of correction of a measured value by an average value.

[Explanation of symbols]

 Reference Signs List 10 automatic guided vehicle (traveling vehicle) 14 traveling route 16 laser radar (object detection device) 20 obstacle 20 obstacle (object) 28 danger level 4 area (obstacle detection required area) 36 measurement required area 37 left vertical boundary ( Boundary line) 38 Right vertical boundary line (Boundary line) 39 Laser beam (Radiation wave)

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[Procedure amendment]

[Submission date] March 10, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 6

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

An object detecting apparatus according to the present invention is provided.
According to (16), a radiation wave (39) is radiated, and an object (20) within a measurement required area (36) is extracted and detected based on the reflected wave. In this object detection device (16),
(20) distance to makes it possible to take the average of the measured values that put in a plurality of measurements at the angular range direction, the boundary line of the measuring area required (36) (37, 38) of the radiation wave (39) In the range close to the direction perpendicular to the radiation direction, increase the number of measurement values for calculating the average in the range close to the direction parallel to the radiation direction of the radiation wave (39) and increase the boundary line (37, 38). The error width in the direction perpendicular to is made uniform along the boundary line (37, 38).

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

According to the object detection device (16) of the present invention, when the boundary line (37, 38) of the measurement required area (36) is close to a right angle to the radiation direction of the radiation wave (39), the radiation wave (39) radiation
Distance to the object (20) in a range near parallel to the
Close the angular interval of the angular position for measuring the separation .

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

The traveling vehicle (10) of the present invention is equipped with the above-mentioned object detection device (16), and the required occupation width for traveling is defined as the left and right width of the measurement required area (36). Left of)
For the range on the right boundary line (37, 38), the radiation wave (39)
A range close to a right angle to the radiation direction of the radiation wave (39)
The range is almost parallel to the radiation direction.

Claims (6)

[Claims] An object detection device (16) for radiating a radiation wave (39) and extracting and detecting an object (20) in a measurement required area (36) based on a reflected wave thereof, comprises: For the distance to the object (20), the average of the measured values in the multiple measurements in the direction of the angle range shall be averaged, and the boundary (37, 38) of the measurement required area (36) will be the radiation wave.
In the range near perpendicular to the radiation direction of (39), the radiation wave (3
9) Increase the number of measurement values to calculate the average for the range close to parallel to the radiation direction, and set the boundaries (37, 38)
An object detection apparatus characterized in that an error width in a direction perpendicular to the direction of the object is made uniform along a boundary line (37, 38). 2. An object detection device (16) for radiating a radiation wave (39) while sweeping it and extracting and detecting an object (20) in a predetermined measurement required area (36) in a sweep direction based on the reflected wave. ), The distance to the object (20) is determined by averaging the measured values at a plurality of angular positions following the sweep direction, and the boundary (37, 38) of the measurement required area (36) is radiated wave (39). In the range close to the direction perpendicular to the radiation direction of the radiation wave (39), the number of measurement angle positions for calculating the average in the range close to the direction parallel to the radiation direction of the radiation wave (39) is increased, and the boundary line (37 An object detection apparatus characterized in that an error width in a direction perpendicular to (38, 38) is made uniform along a boundary line (37, 38). 3. In a range where the boundary (37, 38) of the measurement required area (36) is close to a right angle with respect to the radiation direction of the radiation wave (39), the angle interval of the angular position for measuring the object (20) is An object detection device, wherein the object detection device is dense in a range near parallel to the radiation direction of the radiation wave (39). 4. The method according to claim 1, wherein a time interval for measuring the distance to the object (20) is fixed, and a sweep speed is reduced in an angle range in which the angle intervals of the angular positions are made denser than in an angle range in which the angle positions are made sparse. The object detection device according to claim 3. 5. A method in which the sweep speed is constant, and the range in which the angular interval between the measurement angular positions is dense is larger than the range in which the angular interval is sparse.
4. The object detecting device according to claim 3, wherein a time interval for measuring the distance to (20) is shortened. 6. An object detection device (16) according to any one of claims 1 to 5, wherein the vehicle travels with a required occupied width in travel being the left and right width of the measurement required area (36). Traveling car.