JP2019200701A - Autonomous mobile body - Google Patents

Abstract

To provide an autonomous mobile body that is able to reduce load on a detection unit when detecting an object from three-dimensional data.SOLUTION: An autonomous mobile body 10 comprises a vehicle 20 and an object detection device 30 mounted on the vehicle. The object detection device comprises a three-dimensional distance meter 31 and a control device 32. The control device selects effective data from among three-dimensional data obtained from the three-dimensional distance meter. As the effective data, data in which Z-coordinates fall in a range from a reference position to a predetermined position is selected. The control device converts the effective data into two-dimensional data. The control device detects an object from the two-dimensional data obtained by converting the effective data.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an autonomous mobile body.

  The autonomous mobile body includes an object detection device. An object detection device using a three-dimensional distance meter is described in Patent Document 1, for example. The three-dimensional distance meter acquires three-dimensional data by irradiating a laser while changing the irradiation angle in the horizontal direction and the vertical direction. The object detection apparatus described in Patent Literature 1 includes a three-dimensional distance meter and a detection unit that detects an object from three-dimensional data obtained by the three-dimensional distance meter.

JP 2017-113292 A

By the way, when detecting an object from three-dimensional data, the load of a detection part is large.
The objective of this invention is providing the autonomous mobile body which can reduce the load of a detection part.

  An autonomous mobile body that solves the above-described problem is an autonomous mobile body that includes an object detection device, and the object detection device is configured such that one direction in the horizontal direction is the X axis, and the direction perpendicular to the X axis in the horizontal direction is Y. In a three-axis orthogonal coordinate system with the axis and the vertical direction as the Z-axis, a three-dimensional distance meter that acquires three-dimensional data that is the coordinates of the measurement point irradiated with the laser, and the Z coordinate of the three-dimensional data is the reference A three-dimensional data in a range from a position to a predetermined position is selected as effective data, and a conversion unit that converts the effective data into two-dimensional data that is X-coordinate and Y-coordinate data; and an object from the two-dimensional data A detection unit for detecting.

  The conversion unit converts valid data that is three-dimensional data into two-dimensional data. The detection unit detects an object from the two-dimensional data. Since the object can be detected from the X coordinate and the Y coordinate, the load on the detection unit can be reduced compared to the case of detecting the object from the three-dimensional data.

  For the autonomous mobile body, the detection unit may detect an object from the two-dimensional data closest to the three-dimensional distance meter among the two-dimensional data in which the laser irradiation angle with respect to a horizontal direction is the same angle. Good.

  According to this, the load on the detection unit can be further reduced.

  According to the present invention, the load on the detection unit can be reduced.

Schematic which shows an autonomous mobile body and a tracking object. The figure which shows the irradiation range of a laser typically. The schematic diagram which shows the measurement point which a laser hits, and the three-dimensional coordinate of a measurement point. The schematic diagram which shows the measurement point which a laser hits, and the three-dimensional coordinate of a measurement point. The flowchart which shows the process which a control apparatus performs. The schematic diagram which shows the measurement point in the case of detecting an object using a two-dimensional distance meter. The schematic diagram which shows the measurement point in the case of detecting an object using a three-dimensional distance meter.

Hereinafter, an embodiment of an autonomous mobile body will be described.
As shown in FIG. 1, the autonomous mobile body 10 includes a vehicle 20 and an object detection device 30 mounted on the vehicle 20. The vehicle 20 includes a vehicle body 21, a plurality of wheels 22, and a drive mechanism 23 for causing the vehicle 20 to travel. The drive mechanism 23 is controlled to track the registered tracking target T while avoiding the object detected by the object detection device 30. The vehicle 20 is, for example, a transport cart that transports loads.

  The object detection device 30 includes a three-dimensional distance meter 31 and a control device 32. As the three-dimensional distance meter 31, LIDAR: Laser Imaging Detection and Ranging is used. LIDAR is a range sensor that can recognize the surrounding environment by irradiating the surrounding area with a laser beam and receiving the reflected light reflected from the portion hit by the laser beam.

  As shown in FIGS. 1 and 2, in the present embodiment, the laser irradiable angle θ1 in the vertical direction of the three-dimensional distance meter 31 is 60 °. The laser irradiable angle θ2 in the horizontal direction of the three-dimensional distance meter 31 is 270 °. If the center of the irradiable angles θ1 and θ2 is the reference axis B, the irradiable angle θ1 in the vertical direction is in the range of the reference axis B ± 30 °, and the irradiable angle θ2 in the horizontal direction is the reference axis B ± 135 degrees. Range. The three-dimensional distance meter 31 is attached so that the direction in which the reference axis B extends matches the horizontal direction. The three-dimensional distance meter 31 outputs the three-dimensional data of the measurement point that is the portion hit by the laser to the control device 32.

  Three-dimensional data is three-dimensional coordinates in a three-axis orthogonal coordinate system. The triaxial orthogonal coordinate system is a coordinate system in which one direction in the horizontal direction is the X axis, the direction perpendicular to the X axis in the horizontal direction is the Y axis, and the vertical direction that is perpendicular to the X axis and the Y axis is the Z axis. It is a system. In the present embodiment, the reference axis B is the X axis. The three-dimensional coordinate is a relative coordinate between the three-dimensional distance meter 31 and the measurement point.

  As shown in FIGS. 3 and 4, the three-dimensional coordinates when the shelf 40 is arranged around the vehicle 20 will be described. The shelf 40 includes a plurality of support columns 41 and a plurality of shelf plates 42, and the plurality of shelf plates 42 are supported by the support columns 41. The shelf 40 is arranged so that the support column 41 extends in the vertical direction. Further, it is assumed that the loads W1 and W2 are placed on the shelf plate 42.

  Measurement points P1, P2, and P3 indicate measurement points when the horizontal irradiation angles are the same and the vertical irradiation angles are different. Measurement points P4 and P5 indicate measurement points when the horizontal irradiation angles are the same and the vertical irradiation angles are different. The measurement point P1 and the measurement point P4 have the same vertical irradiation angle and different horizontal irradiation angles. The measurement point P2 and the measurement point P5 have the same vertical irradiation angle and different horizontal irradiation angles.

  The three-dimensional data is the three-dimensional coordinates (Xn, Yn, Zn) of each measurement point Pn. Since the three-dimensional distance meter 31 irradiates the laser while changing the irradiation angle in the vertical direction and the irradiation angle in the horizontal direction, three-dimensional coordinates corresponding to the contour of the object existing around the vehicle 20 can be obtained.

  As shown in FIG. 1, the control device 32 includes a CPU 33 and a storage unit 34 including a RAM and a ROM. The storage unit 34 stores various programs for controlling the autonomous mobile body 10. The control device 32 may include dedicated hardware that executes at least a part of various processes, for example, an application specific integrated circuit (ASIC). The control device 32 may be configured as a circuit including one or more processors that operate according to a computer program, one or more dedicated hardware circuits such as an ASIC, or a combination thereof. The processor includes a CPU and memories such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to perform processing. Memory, ie, computer readable media, includes anything that can be accessed by a general purpose or special purpose computer.

The control device 32 detects an object existing around the vehicle 20 from the detection result of the three-dimensional distance meter 31. Hereinafter, processing for the control device 32 to detect an object will be described.
As shown in FIG. 5, the control device 32 selects valid data from the three-dimensional data obtained from the three-dimensional distance meter 31 in step S <b> 1. As the effective data, data having a Z coordinate from the reference position to a predetermined position is selected. The reference position is the height of the road surface on which the vehicle 20 travels. The predetermined position is set to a value larger than the dimension obtained by adding the height of the load assumed to be mounted on the vehicle body 21 to the height of the vehicle body 21. That is, the predetermined position from the reference position is set in consideration of the height of an object that can be an obstacle when the vehicle 20 moves. For example, the predetermined position is set within a range of 1.5 [m] to 3 [m]. In the example shown in FIG. 3, if the height corresponding to the Z coordinate Z3 of the measurement point P3 is higher than the predetermined position, the valid data is the three-dimensional coordinates of the measurement points P1, P2, P4, and P5.

  As shown in FIG. 5, the control device 32 converts the valid data into two-dimensional data in step S2. Conversion from valid data, which is three-dimensional data, to two-dimensional data is performed by invalidating the Z coordinate. As a result, the three-dimensional data is converted into two-dimensional data having only the X coordinate and the Y coordinate. In the example shown in FIG. 3, the three-dimensional coordinates of P1 (X1, Y1, Z1), P2 (X2, Y2, Z2), P4 (X4, Y4, Z4), and P5 (X5, Y5, Z5) are P1 (X1, Y1), P2 (X2, Y2), P4 (X4, Y4), and P5 (X5, Y5). In other words, the three-dimensional coordinates are collected on the XY plane. Here, the conversion is not limited to the case where the three-dimensional data is changed to different data, and includes a mode in which the following processing is performed while ignoring the Z coordinate. That is, the control device 32 only needs to perform processing using the X coordinate and the Y coordinate in the three-dimensional data obtained by the three-dimensional distance meter 31. The control device 32 functions as a conversion unit.

  As shown in FIG. 5, in step S3, the control device 32 selects, as effective two-dimensional data, two-dimensional data closest to the three-dimensional distance meter 31 from two-dimensional data having the same irradiation angle with respect to the horizontal direction. To do. That is, the control device 32 detects an object using the two-dimensional data closest to the three-dimensional distance meter 31 among the two-dimensional data having the same irradiation angle with respect to the horizontal direction. In the example shown in FIG. 3, P1 (X1, Y1) and P4 (X4, Y4) are effective two-dimensional data.

  The control device 32 detects an object existing around the vehicle 20 using the effective two-dimensional data obtained in steps S1 to S3. In the example shown in FIG. 3, only a few measurement points are shown for convenience of explanation, but actually there are a large number of measurement points and a large number of effective two-dimensional data.

  As shown in FIG. 5, in step S4, the control device 32 performs clustering of the measurement points using the distance between the measurement points, and determines that the clustered point group is one object. Note that the measurement points to be clustered are measurement points represented by effective two-dimensional data. The control device 32 functions as a detection unit that detects an object.

  The control device 32 can grasp the horizontal dimension and the like of the object from the effective two-dimensional data of the measurement points constituting the clustered point group. Thus, the control device 32 can recognize an object that may be an obstacle to movement and the tracking target T.

  The process of step S4 is the same process as when an object is detected using a two-dimensional rangefinder that is a rangefinder that emits laser while changing the irradiation angle in the horizontal direction. Therefore, by performing the processing of step S1 to step S3 before the processing of step S4, the object detection using the three-dimensional distance meter 31 can be performed by the same processing as the object detection using the two-dimensional distance meter. it can.

The control device 32 registers the tracking target T and controls the drive mechanism 23 according to the detected object.
The tracking target T is registered by setting the control device 32 to the registration mode by operating an operation unit or an external device provided in the vehicle 20 in a state where the tracking target T is located in front of the three-dimensional distance meter 31. Done. The control device 32 registers an object located in front of the three-dimensional distance meter 31 as the tracking target T. The registered information is the horizontal dimension of the tracking target T. When tracking the tracking target T, the control device 32 tracks an object that matches the information of the registered tracking target T.

  In order to avoid contact between the object and the vehicle 20, the control device 32 controls the drive mechanism 23 so that the distance between the object and the vehicle 20 is not shorter than a predetermined distance. That is, the control device 32 moves using a position where no point cloud is detected as a movement path.

The operation of this embodiment will be described.
As shown in FIG. 6, it is assumed that the tracking target T passes between two shelves 40 arranged in the horizontal direction. A plurality of loads are arranged on the shelf plate 42 of each shelf 40. On one shelf 40, loads W3, W4, W5 are arranged, and on the other shelf 40, loads W6, W7 are arranged.

  First, the autonomous mobile body 10A that detects an object using the two-dimensional distance meter 31A will be described. In addition, 10 A of autonomous mobile bodies are the structures similar to the autonomous mobile body 10 of embodiment except having replaced with the three-dimensional distance meter 31 and using the two-dimensional distance meter 31A. When using the two-dimensional distance meter 31A, the control device 32 can obtain the horizontal coordinate, that is, the X coordinate and the Y coordinate, for the measurement point P.

  When the two-dimensional distance meter 31A is used, whether or not the laser irradiated from the two-dimensional distance meter 31A hits an object depends on the laser mounting position. In the example shown in FIG. 6, the laser strikes the tracking target T, some loads W3, W5, W6, W7, and some struts 41, but the shelf plate 42 does not strike the laser. Further, the laser does not hit the load W4 whose height is lower than the height irradiated with the laser. Then, the measurement point P does not exist between the loads W3 to W7 or between the loads W3 to W7 and the support column 41, and it is determined that no object exists in this region.

  Due to the difference between the mounting position of the two-dimensional distance meter 31A, that is, the height of the two-dimensional distance meter 31A and the height of the shelf plate 42, the shelf plate 42 does not hit the laser. Further, in the case of an object having a short vertical dimension such as the shelf plate 42, the effective area that can be irradiated with the laser irradiated from the two-dimensional distance meter 31A is small, and detection is difficult. When the shelf plate 42 is not detected, the control device 32 determines that the vehicle 20 can be moved toward the shelf plate 42. For example, since the measurement point P does not exist at the position S indicated by the alternate long and short dash line in FIG. 6, the control device 32 determines that the vehicle 20 can move toward the position S. The control device 32 may move the vehicle 20 to the position S in order to avoid an object, which causes the shelf board 42 and the vehicle 20 to come into contact with each other.

  In the present embodiment, since the three-dimensional distance meter 31 is used, the laser is irradiated while changing the irradiation angle in the vertical direction. As long as the shelf plate 42 exists in any position within the range from the reference position to the predetermined position, the shelf plate 42 is irradiated with the laser. Since the moving direction of the vehicle 20 is the horizontal direction, the contact between the vehicle 20 and the object can be avoided if the size of the object in the horizontal direction can be grasped. That is, since the moving direction of the vehicle 20 is horizontal, contact between the vehicle 20 and the object can be avoided even if the size of the object in the vertical direction cannot be grasped.

  As shown in FIG. 7, by performing the processing of the present embodiment using a three-dimensional distance meter 31, the shelf plate 42 is used as an object from the effective two-dimensional data indicating the measurement point P irradiated on the shelf plate 42. Can be detected. Note that the object is not limited to the shelf 40 and can be detected as an object even if it is an object whose shape changes depending on the position in the vertical direction, or a wall that is partly a window that transmits laser light.

The effect of this embodiment will be described.
(1) The control device 32 converts three-dimensional data into two-dimensional data, and detects an object from the converted two-dimensional data. Compared to the case of detecting an object from three-dimensional data, the load on the control device 32 is reduced. Furthermore, by using the three-dimensional distance meter 31, the laser is irradiated while changing the irradiation angle in the vertical direction. It is possible to detect an object such as the shelf 40 whose shape varies depending on the position in the vertical direction and which may not be detected by the two-dimensional distance meter. In other words, it is possible to achieve both the three-dimensional object detection by the three-dimensional distance meter 31 and the reduction of the load on the control device 32.

(2) Effective 2D data is selected from 2D data. The number of two-dimensional data used to detect the object is reduced, and the load on the control device 32 can be further reduced.
(3) The surrounding environment of the object detection device 30 mounted on a moving body such as the vehicle 20 changes with movement. In order to determine the moving route of the vehicle 20, it is necessary to quickly recognize the surrounding environment, and it is required to increase the object detection speed. In the object detection device 30 of this embodiment, since the load on the control device 32 is reduced, the processing speed of the control device 32 is less likely to decrease compared to the case of detecting an object using three-dimensional data. The detection speed is difficult to decrease. By configuring the object detection device 30 as in the present embodiment, it is easy to satisfy the requirements for the object detection device 30 mounted on the moving body.

(4) Since an object can be detected in three dimensions without using a camera, the manufacturing cost can be reduced.
This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.

  The control device 32 may not select effective two-dimensional data from two-dimensional data in which the irradiation angle with respect to the horizontal direction is the same angle. In this case, it is possible to detect a load placed on the shelf plate 42 or an object placed further behind the shelf plate 42.

O When the three-dimensional distance meter 31 is attached in a state where the reference axis B and the horizontal direction are deviated, the control device 32 may perform coordinate conversion so that the XY plane and the horizontal plane coincide.
The object detection device 30 may be mounted on a moving body other than the one that moves by the wheels 22 such as a biped walking robot. Further, the moving body is not limited to one that moves autonomously, and may be a vehicle that moves by the operation of a passenger.

  When the object detection device 30 is mounted on a vehicle that does not carry a load, the predetermined position may be determined according to the height of the vehicle. That is, the predetermined position differs depending on the target on which the object detection device 30 is mounted.

  The reference position may be a position that is higher than the height of the road surface on which the vehicle 20 travels. The vehicle 20 can get over a step existing on the road surface. The reference position may be a position higher than the step that the vehicle 20 can get over in consideration of the height of the step that the vehicle 20 can get over.

  DESCRIPTION OF SYMBOLS 10 ... Autonomous moving body, 30 ... Object detection apparatus, 31 ... Three-dimensional distance meter, 32 ... Control apparatus (conversion part and detection part).

Claims (2)

An autonomous mobile body equipped with an object detection device,
The object detection device includes:
In a three-axis orthogonal coordinate system in which one direction in the horizontal direction is the X axis, the direction perpendicular to the X axis in the horizontal direction is the Y axis, and the vertical direction is the Z axis, the third order is the coordinate of the measurement point irradiated with the laser A three-dimensional distance meter to acquire the original data;
Among the three-dimensional data, three-dimensional data in which the Z coordinate is in a range from a reference position to a predetermined position is selected as effective data, and the effective data is converted into two-dimensional data that is X-coordinate and Y-coordinate data. A conversion unit;
An autonomous mobile body comprising: a detection unit that detects an object from the two-dimensional data.   2. The autonomous movement according to claim 1, wherein the detection unit detects an object from the two-dimensional data closest to the three-dimensional distance meter among the two-dimensional data in which an irradiation angle of the laser with respect to a horizontal direction is the same angle. body.