Traveling vehicle and autonomous traveling method

Abstract

To provide a traveling vehicle that has improved accuracy of autonomous movement to a target point.SOLUTION: A control unit of a traveling vehicle executes, at a starting position where a traveling vehicle 12 is located separate from a target point, image processing on an image of a marker 35 photographed by an image acquisition unit to recognize the relationship between the relative positions of the traveling vehicle 12 and the marker 35. The control unit causes the traveling vehicle 12 to perform spin rotation, so as to direct the direction of travel of the traveling vehicle 12 to the reference position of the marker 35 on the basis of the relationship between the relative positions. The control unit executes image processing on the image of the marker 35 photographed in a state where the direction of travel of the traveling vehicle 12 is directed to the reference position of the marker 35 to recognize the relationship between the relative postures of the marker 35 and the traveling vehicle 12. The control unit generates a traveling track for moving the traveling vehicle from the start point to a position where the front face of the marker 35 and the direction of travel of the traveling vehicle 12 face each other, on the basis of the relative positions and the relative postures in a state where the direction of travel of the traveling vehicle 12 is directed to the reference position of the marker 35.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a traveling vehicle that autonomously moves to a target point and an autonomous driving method for causing the traveling vehicle that autonomously moves to the target point to reach the target point.

Background Art

[0002] Conventionally, as described in Patent Document 1, for example, a camera installed on a traveling vehicle such as a robot photographs a marker installed at a target point, thereby recognizing the relative position and orientation of the traveling vehicle with respect to the marker, generating a traveling trajectory of the traveling vehicle from the recognized relative position and orientation, and approaching the traveling vehicle toward the target point. There is a known technique.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described technology, it is required that a traveling vehicle that autonomously moves reaches the target point with high accuracy.

[0005] An object of the present invention is to provide a traveling vehicle and an autonomous driving method with improved accuracy of autonomous movement to a target point.

Means for Solving the Problems

[0006] The traveling vehicle of the present invention is a traveling vehicle that autonomously moves to a target point, and includes a main body, a driving unit installed on the main body for moving the main body, an image acquisition unit installed on the main body for photographing the outside of the main body, and a control device to which the driving unit and the image acquisition unit are connected, and which executes output of a driving command for the driving unit and image processing of an image acquired by the image acquisition unit. In a target movement operation for moving the traveling vehicle based on a marker installed corresponding to the target point, at a starting position where the traveling vehicle is located away from the target point, after executing image processing on an image of the marker photographed by the image acquisition unit to recognize the relative position relationship between the traveling vehicle and the marker, the traveling vehicle is spin-rotated on the spot so that the traveling direction of the traveling vehicle faces the reference position of the marker based on the relative position relationship. After that, image processing is executed on the image of the marker photographed in a state where the traveling direction of the traveling vehicle faces the reference position of the marker to recognize the relative posture relationship between the marker and the traveling vehicle, and based on the relative position and the relative posture in a state where the traveling direction of the traveling vehicle faces the reference position of the marker, a traveling trajectory for moving the traveling vehicle from the starting position to a position where the front of the marker and the traveling direction of the traveling vehicle face each other is generated.

Effect of the Invention

[0007] According to the present invention, it is possible to provide a traveling vehicle and an autonomous driving method with improved accuracy of autonomous movement to a target point.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying out the Invention

[0009] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 5.

[0010] FIG. 1 shows a traveling vehicle system 10. The traveling vehicle system 10 includes a traveling vehicle 12 that autonomously moves on the floor surface 11 in the facility to a target point.

[0011] The traveling vehicle 12 includes, for example, an unmanned transport vehicle that carries a transported object or pulls a towing object such as a cart or a trolley and transports it from a predetermined transport source to a transport destination. Further, the traveling vehicle system 10 includes a power supply station 14 that is one of the stop stations 13 as the target point of the traveling vehicle 12. The traveling vehicle system 10 includes a plurality of traveling vehicles 12 and a plurality of power supply stations 14 installed at a plurality of locations.

[0012] The traveling vehicle 12 includes a main body 20, a pair of drive wheels 21 for moving the main body 20, and a plurality of driven wheels 22. The traveling vehicle 12 has one direction as the forward direction and the opposite other direction as the backward direction. Two drive wheels 21 are installed on both sides in the left - right direction that intersects the forward and backward directions, and driven wheels 22 are respectively installed in the front - rear direction of the drive wheels 21 on both sides. The drive wheels 21 on both sides can be individually rotationally driven in the forward and backward directions, and the driven wheels 22 are composed of casters or the like whose direction in the moving direction can freely change. By combining the rotation directions of the drive wheels 21 on both sides, the traveling vehicle 12 can move forward, move backward, move in a curve, spin - rotate (turn at a fixed position), etc.

[0013] The traveling vehicle 12 further includes a power - receiving pad 24 installed above the front surface 23 (or the rear surface in the backward direction) of the main body 20 in the forward direction, and an image - acquisition unit 25 installed below the front surface 23 of the main body 20. The front surface 23 of the main body 20 is formed in the same plane in the vertical direction.

[0014] The power - receiving pad 24 can receive power by a non - contact power - supply method such as an electromagnetic induction method or an electric - field coupling method. The power - receiving pad 24 is formed in a pad shape with a built - in power - receiving coil corresponding to, for example, the electromagnetic induction method.

[0015] The image - acquisition unit 25 is a camera that photographs the external world in front of the traveling vehicle 12 and has a predetermined visual field 26 in the vertical and horizontal directions (FIGS. 5(a) and (b) show the photographed images corresponding to the visual field 26). The image - acquisition unit 25 is installed on the main body 20 such that the lower - end portion (lower side) in the range of the vertical visual - field angle α in the visual field 26 is located substantially horizontally and the center line 27 of the vertical visual - field angle α in the visual field 26 faces upward.

[0016] In addition, the power supply station 14 supplies power for charging the battery of the traveling vehicle 12. The power supply station 14 includes a housing 30 installed on the floor surface 11. On the front side of the housing 30, a facing surface 31 is formed which faces the front surface 23 of the main body 20 of the traveling vehicle 12 that has moved to the power supply station 14. Above this facing surface 31, a facing convex surface 32 is formed which is in close proximity and faces the main body 20 located at the power supply station 14. Also, below the facing surface 31, a facing concave surface 33 is formed which faces the main body 20 and is farther from the main body 20 than the facing convex surface 32.

[0017] The power supply station 14 further includes a power transmission pad 34 installed on the facing convex surface 32 and a marker (marker group) 35 installed on the facing concave surface 33.

[0018] The power transmission pad 34 is capable of transmitting power by a non-contact power supply method such as an electromagnetic induction method or an electric field coupling method. The power transmission pad 34 is formed in a pad shape with a built-in power transmission coil corresponding to, for example, the electromagnetic induction method. Power is transmitted from the power transmission pad 34 to the power reception pad 24 of the traveling vehicle 12 in a non-contact state where the power transmission pad 34 and the power reception pad 24 of the traveling vehicle 12 are in close proximity within a predetermined distance.

[0019] As shown in FIGS. 1 and 2, the marker 35 is, for example, an AR marker with a figure, pattern, etc. displayed on the display surface of the marker 35, and has a large-sized marker 36 and a small-sized marker 37. The large-sized marker 36 is arranged above the opposing concave surface 33, and the small-sized marker 37 is arranged below the opposing concave surface 33, and these markers 36 and 37 are arranged one above the other. When viewed from the front side of the housing 30, both the large-sized marker 36 and the small-sized marker 37 are formed in a rectangular shape, and the centers of the large-sized marker 36 and the small-sized marker 37 are located on the same vertical axis and are provided in the same plane. Further, the centers of the large-sized marker 36 and the small-sized marker 37 and the center of the power transmission pad 34 are located on the same vertical axis. The large-sized marker 36 is formed in a rectangle with a side length of, for example, 80 mm, and the small-sized marker 37 is formed in a rectangle with a side length of, for example, 30 mm.

[0020] Each of the markers 36 and 37 has a pattern recognizable by image processing. By performing image processing on the large-sized marker 36 and the small-sized marker 37 in the captured image, information on the relative posture (relative angle in the horizontal direction) between the large-sized marker 36 and the small-sized marker 37 and the traveling vehicle 12 and information on the relative position (coordinates in the X-axis direction and Y-axis direction in the horizontal direction) with the traveling vehicle 12 can be obtained. As shown in FIG. 4, the relative position of the traveling vehicle 12 is the XY coordinates of the traveling vehicle coordinate system with the straight-ahead direction toward the front of the traveling vehicle 12 as the X-axis direction and the direction intersecting this X-axis direction as the Y-axis direction with respect to the origin 12a, which is the center of the traveling vehicle 12 (the center of spin rotation (turning in place)) in the top view of the traveling vehicle 12. The relative posture of the traveling vehicle 12 is indicated by the inclination angle of the X-axis of the traveling vehicle 12 with respect to each of the markers 36 and 37 (the rotation angle of the vertical axis (Z-axis) passing through the origin 12a, which is the relative yaw angle). Note that the origin 12a is set on the vertical axis (Z-axis) passing through the center position between the pair of drive wheels 21 and perpendicular to the floor surface, and the first reference axis of the plane coordinate system is the X-axis and the second reference axis is the Y-axis.

[0021] Next, the relationship between the field of view 26 of the image acquisition unit 25 of the traveling vehicle 12 and each marker 36, 37 of the power supply station 14 will be described. The image acquisition unit 25 is installed on the traveling vehicle 12 such that the lower end of the small-sized marker 37 is located near the lower end of the vertical field of view angle α within the field of view 26, and the center line 27 of the vertical field of view angle α in the field of view 26 faces upward. Further, in a state where the traveling vehicle 12 is positioned at the power supply station 14 which is the target point, the entire small-sized marker 37 is included within the field of view 26 of the image acquisition unit 25, and a part or all of the large-sized marker 36 is not included. Also, in a state where the traveling vehicle 12 is positioned at the power supply station 14 which is the target point and the main body 20 of the traveling vehicle 12 is in close proximity to and facing the opposing convex surface 32 of the stop station 14, the small-sized marker 37 of the opposing concave portion 33 is located farther than the shortest shooting distance of the image acquisition unit 25, and the small-sized marker 37 can be photographed (focused) by the image acquisition unit 25.

[0022] Next, FIG. 3 shows a block diagram of the traveling vehicle system 10. The traveling vehicle system 10 includes a traveling vehicle 12, a power supply station 14, a management terminal 40 which is a management device, and the like. The traveling vehicle 12 and the management terminal 40 can communicate with each other by wireless communication, and the power supply station 14 and the management terminal 40 can communicate with each other by wired communication or wireless communication.

[0023] The traveling vehicle 12 includes a drive unit 41, an external sensor unit 42, an internal sensor unit 43, a power reception system 44, a battery 45, and a control device 46.

[0024] The drive unit 41 includes two motors that individually rotationally drive two drive wheels 21.

[0025] The external sensor unit 42 includes an image acquisition unit 25 which is a camera, and also includes an optical sensor, an ultrasonic sensor, etc. that detect obstacles existing in the moving direction or detect the distance to an object.

[0026] The internal sensor unit 43 acquires the moving direction and moving amount of the traveling vehicle 12 by means of an encoder that detects the rotation amount of each drive wheel 21, an acceleration sensor and an angular velocity sensor installed on the traveling vehicle 12, etc.

[0027] The power receiving system 44 is a power receiving side device related to the charging of the battery 45, and includes a power receiving pad 24 and a power receiving unit 47. The power receiving pad 24 receives power wirelessly transmitted from the power transmission pad 34. The power receiving unit 47 converts the power received by the power receiving pad 24 into a predetermined charging power to charge the battery 45.

[0028] The battery 45 is the power source of the traveling vehicle 12 and supplies power to each electrical device provided in the traveling vehicle 12.

[0029] The control device 46 controls the traveling vehicle 12, and includes a drive control unit 48, an image processing unit 49, an odometry unit 50, and a power receiving control unit 51. The drive control unit 48 controls each motor of the drive unit 41, that is, controls the movement of the traveling vehicle 12. The image processing unit 49 executes image processing on the images of the markers 36, 37 to recognize the relative position and relative attitude of the traveling vehicle 12 with respect to the markers 36, 37. The odometry unit 50 calculates the movement amount of the traveling vehicle 12 based on the information of the internal sensor unit 43 and estimates the self-position and attitude of the traveling vehicle 12. The power receiving control unit 51 controls the charging of the battery 45 by the power receiving system 44.

[0030] The control device 46 is connected to the drive unit 41 and the image acquisition unit 25, and executes the output of the drive command for the drive unit 41 and the image processing of the image acquired by the image acquisition unit 25. Further, in the target movement operation of moving the traveling vehicle 12 based on the large-size marker 36 and the small-size marker 37 installed at the power supply station 14 which is the target point, the control device 46 executes image processing on the image captured by the image acquisition unit 25 of the traveling vehicle 12 located away from the target point, recognizing the relative attitude of the traveling vehicle 12 with respect to the large-size marker 36 and, and recognizing the relative position of the traveling vehicle 12 with respect to the small-size marker 37, and generating a traveling trajectory for moving to the target point from the recognized relative attitude and relative position of the traveling vehicle 12. The control device 46 drives the drive unit 41 so that the traveling vehicle 12 moves along the traveling trajectory, and when the traveling vehicle 12 approaches the target point, executes image processing on the captured image of the small-size marker 37 to recognize the relative position and relative attitude of the traveling vehicle 12 based on the small-size marker 37. At this time, during the movement of the traveling vehicle 12 towards the target point, the marker to be recognized is changed so that the recognition of the relative attitude of the traveling vehicle 12 is recognized based on the small-size marker 37 instead of the large-size marker 36.

[0031] Also, the power supply station 14 includes a power transmission system 53 and a marker 35. The power transmission system 53 is a power transmission side device related to the charging of the battery 45, and includes a power transmission pad 34 and a power transmission unit 54. The power transmission pad 34 transmits power to the power reception pad 24 in a non-contact manner. The power transmission unit 54 converts power and causes it to be transmitted from the power transmission pad 34. The marker 35 includes a large-size marker 36 and a small-size marker 37.

[0032] In addition, the management terminal 40 includes a work management unit 56, a map management unit 57, a traveling vehicle management unit 58, and a power supply station management unit 59. The work management unit 56 manages the work information and work progress information of the traveling vehicle 12, the work assignment to the traveling vehicle 12, and the like. The map management unit 57 manages the arrangement of each device on the floor in the facility as coordinate information. The traveling vehicle management unit 58 manages the working status of the traveling vehicle 12 and the remaining power stored in the battery 45, and notifies the map coordinates of the target point to be moved in the work instruction for the traveling vehicle 12. The power supply station management unit 59 manages the operating status of the power supply station 14.

[0033] Next, the operation of the traveling vehicle system 10 will be described.

[0034] The management terminal 40 assigns work to the traveling vehicle 12 that is the work target, and the traveling vehicle 12 to which the work is assigned executes work such as transporting the transported goods.

[0035] The management terminal 40 monitors the remaining power stored in the battery 45 of each traveling vehicle 12. When detecting a traveling vehicle 12 whose remaining power of the battery 45 is below the reference value, the management terminal 40 removes the traveling vehicle 12 from the work targets as a vehicle to be charged and reserves an available power supply station 14.

[0036] The management terminal 40 instructs the traveling vehicle 12 that is the vehicle to be charged to move to the reserved power supply station 14.

[0037] The traveling vehicle 12 that is the vehicle to be charged and has received the instruction from the management terminal 40 executes the target movement operation to the power supply station 14 which is the target point. In this target movement operation, during the movement to the power supply station 14, the vehicle temporarily stops at a position slightly away from the power supply station 14 (for example, about 1 m in front) as the waypoint P1 (see Fig. 4(a)), searches for the markers 36, 37 of the power supply station 14, and then performs an approach movement operation to the markers 36, 37 of the power supply station 14. Note that the waypoint P1 is the starting position where the positioning operation, which is the final process of the target movement operation of the autonomous movement of the traveling vehicle 12 to the target position, starts.

[0038] As shown in FIG. 4(a), the traveling vehicle 12 temporarily stops at a passing point P1 on the way to the power feeding station 14, processes the captured image captured by the image acquisition unit 25, and searches for the markers 36 and 37. When the markers 36 and 37 are confirmed, the XY coordinates of the small-sized marker 37 with respect to the origin 12a of the traveling vehicle 12 are acquired from the small-sized marker 37 (the large-sized marker 36 may also be used). This step is referred to as the first marker position recognition step.

[0039] As shown in FIG. 4(b), with the front surface 23 of the traveling vehicle 12 facing the markers 36 and 37 of the power feeding station 14, the traveling vehicle 12 is spin-rotated (swiveled in place) at the passing point P1 so that the X-axis extending forward from the origin 12a of the traveling vehicle 12 overlaps with the center in the left-right direction as the reference position of the markers 36 and 37, and the traveling direction is directed toward the center of the markers 36 and 37. This step is referred to as the first spin step.

[0040] The captured image captured by the image acquisition unit 25 of the traveling vehicle 12 is processed to recognize the relative posture of the traveling vehicle 12 with respect to the large-sized marker 36. This relative posture is indicated by the relative yaw angle of the traveling vehicle, and can also be recognized as the angle θ formed by the virtual vertical line 61 perpendicular to the center of the surface of the large-sized marker 36 and the X-axis direction extending forward of the traveling vehicle 12. Further, the captured image captured by the image acquisition unit 25 of the traveling vehicle 12 is processed to recognize the relative position of the traveling vehicle 12 with respect to the small-sized marker 37. This relative position is the XY coordinates of the traveling vehicle 12 with respect to the small-sized marker 37, and the value of the Y coordinate is 0. This step is referred to as the second marker recognition step. Also, the recognition of the relative position of the traveling vehicle 12 may be performed by recognizing the relative position again from the small-sized marker 37 after the completion of the spin rotation of the traveling vehicle 12 to update the relative position, or the relative position may be continuously updated by spin-rotating the traveling vehicle 12 while continuously recognizing the relative position from the small-sized marker 37.

[0041] At this time, since the traveling vehicle 12 located at the via point P1 is at a position slightly away from the power supply station 14, the relative position can be recognized from the small-sized marker 37 in the captured image captured by the image acquisition unit 25 of the traveling vehicle 12. However, regarding the relative attitude (angle θ), since it is recognized from the inclination of the small-sized marker 37, etc., the small-sized marker 37 in the captured image may be too small and the recognition accuracy may be poor. On the other hand, from the large-sized marker 36 recognized from the captured image captured by the image acquisition unit 25 of the traveling vehicle 12, it is larger than the small-sized marker 37 in the captured image, and the relative attitude (angle θ) can be recognized with high accuracy from the inclination of the large-sized marker 36, etc.

[0042] The traveling vehicle 12 that has recognized the relative attitude and relative position with respect to the markers 36 and 37 of the power supply station 14 generates a traveling trajectory in which it turns around and approaches the front of the markers 36 and 37 of the power supply station 14 from the via point P1, and moves along the traveling trajectory.

[0043] The traveling trajectory includes a first traveling trajectory that moves the origin 12a of the traveling vehicle 12 to an intermediate point P2 set on a virtual vertical line 61 that is a line perpendicular to the display surface of the markers 36 and 37 and extends from the center of the display surface, and a second traveling trajectory that the traveling vehicle 12 moves from the intermediate point P2 toward the markers 36 and 37 of the power supply station 14. Note that the traveling trajectory is a series of operations of the traveling vehicle 12 in which straight traveling and spin rotation of the traveling vehicle 12 are combined, and the spin angle and traveling distance (linear distance) of the traveling vehicle 12 until it arrives at the intermediate point P2 are calculated from the inclination angle between the marker 35 and the traveling vehicle 12, and the distance (X coordinate) between the marker 35 and the traveling vehicle 12. Then, based on the inclination angle (relative yaw angle) of the traveling vehicle 12 with respect to the large-sized marker 36 and the XY coordinates of the small-sized marker 37, a traveling trajectory of the traveling vehicle 12 that moves onto the virtual vertical line 61 and turns around to the front of the marker 35 is generated. Note that this step is called the trajectory generation step.

[0044] The intermediate point P2 set on the virtual vertical line 61 is the point where the virtual line extending from the origin 12a of the traveling vehicle 12 intersects the virtual vertical line 61 at a right angle. Alternatively, it may be a point closer to the markers 36, 37 of the power supply station 14 than the point where the virtual line extending from the origin 12a of the traveling vehicle 12 intersects the virtual vertical line 61 at a right angle. Also, it is sufficient if the origin 12a of the traveling vehicle 12 can move from the passing point P1 to the intermediate point P2, and it is sufficient if the origin 12a of the traveling vehicle 12 can move from the passing point P1 to the intermediate point P2.

[0045] And in the second marker recognition step in FIG. 4(b), the traveling vehicle 12 facing the direction of the marker 35 is temporarily stopped for a predetermined time, and the image acquisition unit 25 is made to photograph the marker 35 a plurality of times. Then, the relative angle of the traveling vehicle 12 with respect to the marker 35 is obtained from the plurality of marker photographed images. The median value of the relative angles obtained from the marker 35 in the plurality of photographed images is used as the relative angle for orbit generation, thereby improving the accuracy of the positioning travel.

[0046] FIGS. 4(c) to (h) show the target movement operation of the traveling vehicle 12 along the traveling orbit to the power supply station 14 which is the target point. As shown in FIG. 4(c), the traveling vehicle 12 spins and travels toward the intermediate point P2, and after the traveling direction of the traveling vehicle 12 faces the intermediate point P2, it moves forward. As shown in FIG. 4(d), when the origin 12a of the traveling vehicle 12 reaches the intermediate point P2 on the virtual vertical line 61, the traveling vehicle 12 temporarily stops. Note that the process in FIG. 4(c) is called the second spin step, and the process in FIG. 4(d) is called the transfer step.

[0047] As shown in FIG. 4(e), the traveling vehicle 12 spins and rotates so that the front surface 23 of the traveling vehicle 12 faces the markers 36, 37 of the power supply station 14, and the traveling direction of the traveling vehicle 12 is made to face the markers 36, 37. By making the traveling vehicle 12 face each of the markers 36, 37 of the power supply station 14, the photographed image taken by the image acquisition unit 25 of the traveling vehicle 12 is image-processed to recognize the relative attitude from the large-size marker 36 and the relative position from the small-size marker 37. Note that the process in FIG. 4(e) is called the third spin step.

[0048] Here, when moving from the passing point P1 to the intermediate point P2, instead of FIGS. 4(c) to (d), as shown in FIGS. 5(c) to (d), the traveling direction of the traveling vehicle 12 is spin-rotated so as to face a predetermined angle with respect to the virtual vertical line 61, and it is moved in an oblique direction with respect to the virtual vertical line 61, and then, as shown in FIG. 4(e), it may be spin-rotated by a predetermined angle to change the traveling direction.

[0049] Also, in the steps of FIGS. 4(c) to (e) and FIGS. 5(c) to (d), the markers 36 and 37 may fall out of the field of view of the image acquisition unit 25, and it is possible to travel based on the odometry information of the in-vehicle sensor 43 along the generated trajectory. In addition, in the steps of FIGS. 4(c) to (e), the traveling vehicle 12 can also be made to travel based on the traveling distance and the spin angle of the generated traveling trajectory without using the information on the relative position and relative attitude from the markers 36 and 37.

[0050] Further, since the traveling vehicle 12 is at a position away from the power supply station 14, both the large-sized marker 36 and the small-sized marker 37 are included in the field of view 26 of the image acquisition unit 25. The captured image taken by the image acquisition unit 25 at this time is shown in FIG. 6(a). Both the large-sized marker 36 and the small-sized marker 37 are included within the frame of the captured image corresponding to the field of view 26 of the image acquisition unit 25, and the large-sized marker 36 and the small-sized marker 37 are recognized from this captured image.

[0051] Subsequently, as shown in FIGS. 4(f) and 1(a), the traveling vehicle 12 facing the markers 36 and 37 of the power supply station 14 moves forward so as to approach the markers 36 and 37 of the power supply station 14. At this time, the traveling vehicle 12 processes the captured image taken by the image acquisition unit 25 and moves forward while confirming the relative attitude recognized from the large-sized marker 36 and the relative position recognized from the small-sized marker 37. When there is a deviation in the relative attitude with respect to the large-sized marker 36, the rotation of the drive wheels 21 on both sides is individually controlled to correct the relative attitude of the traveling vehicle 12 with respect to the large-sized marker 36 while moving forward.

[0052] As shown in FIGS. 4(g) and 1(c), when the traveling vehicle 12 approaches the markers 36 and 37 of the power feeding station 14, the entire small-sized marker 37 is included in the visual field 26 of the image acquisition unit 25, but a part of the upper side of the large-sized marker 36 is not included. The captured image taken by the image acquisition unit 25 at this time is shown in FIG. 6(b). The entire small-sized marker 37 is included within the frame of the captured image corresponding to the visual field 26 of the image acquisition unit 25, but a part of the upper side of the large-sized marker 36 is not included. From this captured image, the large-sized marker 36 is not recognized, and only the small-sized marker 37 is recognized.

[0053] Therefore, the traveling vehicle 12 recognized the relative attitude with respect to the large-sized marker 36 until just before and approached and moved towards the markers 36 and 37 of the power feeding station 14. However, after the large-sized marker 36 is no longer recognized, it recognizes the relative attitude from the small-sized marker 37 and approaches and moves towards the markers 36 and 37 of the power feeding station 14. Note that the information on the relative attitude is acquired simultaneously from both the markers 36 and 37. When the large-sized marker 36 protrudes from the visual field of the image acquisition unit 25 and cannot be recognized, the information on the relative attitude acquired from the small-sized marker 37 is used to overwrite the information on the relative attitude acquired from the large-sized marker 36 so as to correct it. This also includes changing the recognized markers 36 and 37 when the recognition target switches between the markers 36 and 37.

[0054] At this time, since the traveling vehicle 12 approaches the markers 36 and 37 of the power feeding station 14 and the small-sized marker 37 in the captured image taken by the image acquisition unit 25 is large, the relative attitude can be recognized with high accuracy even from the small-sized marker 37.

[0055] After that, when the moving vehicle 12 determines that it has reached the power supply station 14, which is the target point, from the relative position with respect to the small-sized marker 37, it stops moving. If the relative position and relative attitude of the moving vehicle 12 with respect to the small-sized marker 37 are normal, it is determined that the power receiving pad 24 of the moving vehicle 12 and the power transmitting pad 34 of the power supply station 14 are facing each other at a predetermined interval, and the power transmitting pad 34 of the power supply station 14 transmits power to the power receiving pad 24 of the moving vehicle 12, and starts charging the battery 45 of the moving vehicle 12. The steps in FIGS. 4(e) to 4(h) are referred to as the approaching driving step.

[0056] In addition, if it is recognized that the origin 12a of the moving vehicle 12 is not located on the virtual vertical line 61 but is laterally displaced between FIGS. 4(e) and 4(h), the moving vehicle 12 is rotated laterally with respect to the small-sized marker 37 as shown in FIGS. 7(a) to 7(d), and then advanced until the origin 12a of the moving vehicle 12 moves onto the virtual vertical line 61, and then rotated until the moving vehicle 12 faces the small-sized marker 37.

[0057] Also, if there is an abnormality in the relative position and relative attitude of the moving vehicle 12 with respect to the small-sized marker 37, the moving vehicle 12 first retreats to a predetermined retreat position, and then executes the target movement operation toward the power supply station 14, which is the target point of the moving vehicle 12, again.

[0058] In this way, the coordinates of the relative position and the inclination angle (relative yaw angle) of the relative attitude of the moving vehicle 12 with respect to the marker 35 are recognized in the marker 35 coordinate recognition step and the marker 35 angle recognition step, and based on the coordinates of this relative position and the inclination angle of the relative attitude, the traveling accuracy can be improved by generating the traveling trajectory of the moving vehicle 12. Furthermore, the traveling trajectory can be generated by the operations of spin rotation and straight-ahead driving, and the moving vehicle 12 can still travel even if the marker 35 goes out of the field of view of the image acquisition unit 25 during the turning-in operation. In addition, the reliability of the internal information such as odometry can be ensured rather than traveling on a curved trajectory, and the traveling accuracy of the moving vehicle 12 is improved.

[0059] In addition, since the traveling path of the traveling vehicle 12 is composed of spin rotation and straight traveling, the traveling path can be made more compact than when the traveling path includes curve traveling, and the via point P1 can be set at a position closer to the marker 35. As a result, even if the size of the marker 35 installed near the target position is reduced, the traveling vehicle 12 can start the positioning operation from the state of approaching the marker 35. Therefore, the marker 35 can be photographed within the field of view of the image acquisition unit 25 with a size equal to or larger than a certain value, and the degree of freedom in installing the marker 35 is improved.

[0060] Furthermore, since the traveling vehicle 12 is spin-rotated so that the X-axis direction of the traveling vehicle 12 overlaps with the reference position of the marker 35 and then the relative yaw angle of the traveling vehicle 12 with respect to the marker 35 is recognized, the reliability of the relative yaw angle is increased. In addition, since the recognition accuracy of the relative yaw angle is improved by using the median value of the relative yaw angles obtained from the images of a plurality of markers 35, as a result, the accuracy of the trajectory generated using the relative yaw angle is also improved.

[0061] Note that the stop station 13 is not limited to the power supply station 14, and may be a station at the source that receives the conveyed object mounted on the traveling vehicle 12 or connects a towing object to the traveling vehicle 12, or a station at the destination that takes out the conveyed object from the traveling vehicle 12 or removes the towing object from the traveling vehicle 12.

[0062] As described above, the embodiments of the present invention and their modifications have been described. However, various combinations of configurations, partial omissions, replacements, and changes are also possible.

Explanation of Reference Numerals

[0063] 12 Traveling vehicle 20 Main body 25 Image acquisition unit 35 Marker 41 Driving unit 46 Control device 61 Virtual vertical line P1 Via point (starting position) P2 Intermediate point

Claims

1. A traveling vehicle that autonomously moves to a target location, comprising: a main body; a drive unit installed on the main body for moving the main body; an image acquisition unit installed on the main body for photographing the outside of the main body; a control device to which the drive unit and the image acquisition unit are connected, and which executes output of a drive command for the drive unit and image processing of an image acquired by the image acquisition unit; the control device: in a target movement operation of moving the traveling vehicle based on a marker installed corresponding to the target location, at a starting position where the traveling vehicle is located away from the target location, after executing image processing on the image of the marker photographed by the image acquisition unit to recognize the relative position relationship between the traveling vehicle and the marker, spinning and rotating the traveling vehicle on the spot so that the traveling direction of the traveling vehicle faces the reference position of the marker, and then executing image processing on the image of the marker photographed in a state where the traveling direction of the traveling vehicle faces the reference position of the marker to recognize the relative posture relationship between the marker and the traveling vehicle; generating a travel trajectory for moving the traveling vehicle from the starting position to a position where the front of the marker and the traveling direction of the traveling vehicle face each other based on the relative position and the relative posture in a state where the traveling direction of the traveling vehicle faces the reference position of the marker; A traveling vehicle characterized by the above.

2. The control device: after the traveling direction of the traveling vehicle faces the reference position of the marker, in a state where the traveling vehicle is stopped, causing the image acquisition unit to photograph the marker a plurality of times to acquire a plurality of images of the marker, and determining the relative posture from the median value of a plurality of pieces of relative posture information obtained by image processing on each of the plurality of images of the marker; The traveling vehicle according to claim 1, characterized by the above.

3. The control device: recognizes the relative position as the coordinates of the position of the marker in a traveling vehicle coordinate system with the traveling vehicle as the origin; recognizes the relative posture as the relative yaw angle of the traveling vehicle with respect to the display surface of the marker in a state where the traveling direction of the traveling vehicle faces the reference position of the marker; The traveling vehicle according to claim 1 or 2, characterized by the above.

4. a main body; a drive unit installed on the main body for moving the main body; an image acquisition unit installed on the main body for photographing the outside of the main body; A control device to which the drive unit and the image acquisition unit are connected, and which executes output of a drive command of the drive unit and image processing for a marker in an image acquired by the image acquisition unit A self-driving method for moving a traveling vehicle equipped with the above to a target point corresponding to the marker, comprising: by the control device, at a starting position where the traveling vehicle is located away from the target point, from an image of the marker captured by the image acquisition unit of the traveling vehicle, with the straight-ahead direction of the traveling vehicle as the X-axis and the direction orthogonal to the X-axis as the Y-axis in a vehicle coordinate system of the traveling vehicle, a first marker recognition step of recognizing the XY coordinates of the marker; a first spin step of spin-rotating the traveling vehicle in place by the drive unit until the X-axis of the traveling vehicle overlaps the reference position of the marker; after the first spin step, a second marker recognition step of recognizing the relative yaw angle of the traveling vehicle with respect to the marker from the image of the marker acquired by the image acquisition unit; Based on the XY coordinates of the marker and the relative yaw angle after the first spin step, an orbit generation step of generating a travel orbit for the traveling vehicle to move to an intermediate point located away from the marker on a virtual vertical line orthogonal to the display surface of the marker and extending from the reference position of the marker is executed A self-driving method characterized by the above.

5. In the orbit generation step, the spin angle of a second spin step of spin-rotating the traveling vehicle until the X-axis of the traveling vehicle overlaps the intermediate point, the travel distance of a transfer step of driving the traveling vehicle straight until it reaches the intermediate point, and the spin angle of a third spin step of spin-rotating the traveling vehicle that has reached the intermediate point to face the reference position of the marker are generated The self-driving method according to claim 4, characterized by the above.

6. The origin of the vehicle coordinate system is located at the center of spin rotation of the traveling vehicle, the spin angles in the first spin step, the second spin step, and the third spin step are rotation angles based on the origin, and the travel distance in the transfer travel step is the distance until the origin overlaps the intermediate point The self-driving method according to claim 5, characterized by the above.

7. In the step of running the traveling vehicle based on the track generation step, the drive unit is driven based on the travel distance and the spin angle of the generated travel track without using the information recognized from the marker. The autonomous driving method according to claim 5, characterized by the above.

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