Traveling vehicle system and autonomous traveling method

Abstract

To provide a traveling vehicle system with the improved accuracy of autonomous movement to a target point.SOLUTION: A traveling track generation unit generates a traveling track for causing the traveling vehicle to travel to a target point. At a start position where the traveling vehicle 12 is located away from the target point, an image process is performed on an image of a marker 35 photographed by an image acquisition unit of the traveling vehicle 12 to recognize the relative position between the marker 35 and the traveling vehicle 12. The relative position and the relative posture between the marker 35 and the traveling vehicle 12 are recognized by executing an image process on an image of the marker 35 photographed by the image acquisition unit of the traveling vehicle 12 traveling in a state of facing the reference position of the marker based on the relative position. A traveling track for causing the traveling vehicle 12 to travel to a position where the front of the marker 35 and the traveling direction of the traveling vehicle 12 face each other is generated based on the relative position and the relative posture between the marker 35 and the traveling vehicle 12.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a traveling vehicle system that autonomously moves a traveling vehicle to a target point, and an autonomous traveling method that causes a traveling vehicle that autonomously moves to a target point to arrive at the target point. [Background technology]

[0002] Conventionally, as described in Patent Document 1, for example, a technology has been known in which 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 for the traveling vehicle from the recognized relative position and orientation, and driving the traveling vehicle toward the target point. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-121928 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned technology, it is required that the autonomously moving vehicle reach the target point with high accuracy.

[0005] The present invention provides a traveling vehicle system and an autonomous traveling method that improve the accuracy of autonomous traveling to a destination. [Means for solving the problem]

[0006] The traveling vehicle system of the present invention is a traveling vehicle system that generates a traveling trajectory for autonomously traveling to a target point for a traveling vehicle having a main body unit, a drive unit installed on the main body unit to travel the main body unit, and an image acquisition unit installed on the main body unit to photograph the outside world of the main body, and is equipped with a traveling trajectory generation unit that generates a traveling trajectory for traveling the traveling vehicle to the target point based on a marker installed corresponding to the target point photographed by the image acquisition unit, and the traveling trajectory generation unit performs image processing on the image of the marker photographed by the image acquisition unit at a starting position where the traveling vehicle is located away from the target point to recognize the relative position between the marker and the traveling vehicle, performs image processing on the image of the marker photographed by the image acquisition unit of the traveling vehicle that has traveled in a state facing a reference position of the marker based on the relative position to recognize the relative position and relative attitude between the marker and the traveling vehicle, and generates a traveling trajectory for traveling the traveling vehicle to a position where the front of the marker and the traveling direction of the traveling vehicle are opposite each other based on the relative position and relative attitude between the marker and the traveling vehicle. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a traveling vehicle system and an autonomous traveling method that improve the accuracy of autonomous movement to a destination. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B show an embodiment of the traveling vehicle system of the present invention, in which (a) is a side view of the traveling vehicle positioned away from the power supply station, (b) is a front view of the power supply station, and (c) is a side view of the traveling vehicle approaching the power supply station. [Figure 2] FIG. 2 is a front view of a marker installed in the power supply station. [Figure 3] FIG. 2 is a block diagram of the traveling vehicle system. [Figure 4] 4A to 4H are explanatory diagrams showing a target movement operation of the traveling vehicle to a power supply station. [Figure 5]10(c) to 10(e) are explanatory diagrams showing other examples of the target movement operation of the traveling vehicle to the power supply station. [Figure 6] 1A and 1B show images captured by the image capture unit of the vehicle, where (a) is an explanatory diagram of an image captured when the vehicle is located away from the power supply station, and (b) is an explanatory diagram of an image captured when the vehicle is approaching the power supply station. [Figure 7] 10A to 10D are explanatory diagrams showing the operation of the traveling vehicle when it is recognized that the origin of the traveling vehicle is not on the imaginary vertical line of the marker during the target movement operation of the traveling vehicle to the power supply station. [Figure 8] 10(a) to 10(f) are explanatory diagrams showing other examples of the target movement motion of the traveling vehicle. [Figure 9] 10(a) to 10(i) are explanatory diagrams showing still another example of the target movement motion of the traveling vehicle. [Figure 10] 10A to 10H are explanatory diagrams showing examples of a target movement operation in which the traveling vehicle tows a towed object and moves the towed object backward toward a target point. [Figure 11] FIG. 2 is an explanatory diagram showing the relationship between the traveling vehicle, the towing object, and the markers. [Figure 12] 10 is an explanatory diagram showing the relationship between the traveling vehicle, the towing object, and the marker in yet another example of a target movement operation when the traveling vehicle tows the towing object. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will now be described with reference to the drawings.

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

[0011] The traveling vehicle 12 includes, for example, an automated guided vehicle that carries an object to be transported or tows a towing object such as a car truck or a dolly and transports the object from a predetermined source to a destination. Furthermore, the traveling vehicle system 10 includes a power supply station 14, which is one of the stop stations 13, as a destination point for 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 comprises a main body 20, a pair of drive wheels 21 and a plurality of driven wheels 22 for moving the main body 20. The traveling vehicle 12 has one direction designated as the forward direction and the other direction designated as the reverse direction, with two drive wheels 21 installed on both sides in a left-right direction intersecting the forward and reverse directions, and driven wheels 22 installed in the front and rear directions of the drive wheels 21 on both sides. The drive wheels 21 on both sides can be driven to rotate independently in the forward and reverse directions, and the driven wheels 22 are formed by casters or the like whose direction of movement can be freely changed. Depending on the combination of the rotation directions of the drive wheels 21 on both sides, the traveling vehicle 12 can move forward, backward, turn, spin (turn in place), and so on.

[0013] The traveling vehicle 12 further includes a power receiving pad 24 installed on the upper side of the front surface 23 of the main body 20 in the forward direction (or the rear surface in the backward direction), and an image acquisition unit 25 installed on the lower side of the front surface 23 of the main body 20. The front surface 23 of the main body 20 is formed on 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 the shape of a pad with a built-in power receiving coil compatible with the electromagnetic induction method.

[0015] Image acquisition unit 25 is a camera that captures images of the external environment ahead of traveling vehicle 12, and has a predetermined field of view 26 in the vertical and horizontal directions (photographed images corresponding to field of view 26 are shown in FIGS. 6(a) and 6(b)). Image acquisition unit 25 is installed on main body 20 so that the vicinity of the lower end (bottom side) of the range of vertical viewing angle α in field of view 26 is positioned approximately horizontally, and so that center line 27 of vertical viewing angle α in field of view 26 faces upward.

[0016] The power supply station 14 supplies power to charge the battery of the traveling vehicle 12. The power supply station 14 includes a housing 30 installed on the floor surface 11. A facing surface 31 is formed on the front side of the housing 30, facing the front surface 23 of the main body 20 of the traveling vehicle 12 that has moved to the power supply station 14. A facing convex surface 32 that closely faces the main body 20 located at the power supply station 14 is formed above the facing surface 31, and a facing concave surface 33 that faces the main body 20 but is farther away from the main body 20 than the facing convex surface 32 is formed below the facing surface 31.

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

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

[0019] As shown in FIGS. 1 and 2 , the marker 35 is an AR marker with, for example, a figure or pattern displayed on the display surface of the marker 35, and includes a large marker 36 and a small marker 37. The large marker 36 is disposed above the opposing concave surface 33, and the small marker 37 is disposed below the opposing concave surface 33, with these markers 36, 37 arranged vertically side by side. When viewed from the front side of the housing 30, the large marker 36 and the small marker 37 are both rectangular, with their centers aligned vertically on the same axis and in the same plane. Furthermore, the centers of the large marker 36 and the small marker 37 and the center of the power transmission pad 34 are aligned vertically on the same axis. The large marker 36 is rectangular, with sides measuring, for example, 80 mm, and the small marker 37 is rectangular, with sides measuring, for example, 30 mm.

[0020] Each of the markers 36, 37 has a pattern that can be recognized by image processing. By performing image processing on the large-sized marker 36 and the small-sized marker 37 in the captured image, it is possible to obtain information on the relative attitude (relative angle in the horizontal direction) of 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 horizontal direction of the X-axis and Y-axis) of the large-sized marker 36 and the small-sized marker 37 and the traveling vehicle 12. As shown in FIG. 4 , the relative position of the traveling vehicle 12 is represented by XY coordinates in a traveling vehicle coordinate system in which, with respect to an origin 12a that is the center of the traveling vehicle 12 (the center of a spin rotation (turning on the spot)), the X-axis direction is the direction straight ahead of the traveling vehicle 12, and the Y-axis direction is the direction intersecting with the X-axis direction. The relative attitude of the traveling vehicle 12 is represented by the tilt angle of the X-axis of the traveling vehicle 12 with respect to each of the markers 36, 37 (the rotation angle of a vertical axis (Z-axis) passing through the origin 12a, which is the relative yaw angle). In other words, the origin 12a is set on a vertical axis (Z-axis) that passes through the center position between the pair of drive wheels 21 and is 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] 1, the relationship between the field of view 26 of the image acquisition unit 25 of the traveling vehicle 12 and the markers 36, 37 of the power supply station 14 will be described. The image acquisition unit 25 is installed on the traveling vehicle 12 so that the bottom end of the small marker 37 is located near the bottom end of the vertical field of view α within the field of view 26, and the center line 27 of the vertical field of view α within the field of view 26 faces upward. Furthermore, when the traveling vehicle 12 is located at the power supply station 14, which is the destination point, the field of view 26 of the image acquisition unit 25 includes the entire small marker 37, but excludes some or all of the large marker 36. Furthermore, when the vehicle 12 is positioned at the target point, the power supply station 14, and the main body 20 of the vehicle 12 is closely facing the opposing convex surface 32 of the power supply station 14, the small marker 37 on the opposing concave surface 33 is located farther than the shortest shooting distance of the image acquisition unit 25, and a relationship exists in which the small marker 37 can be photographed (focused) by the image acquisition unit 25.

[0022] Next, a block diagram of the traveling vehicle system 10 is shown in Figure 3. The traveling vehicle system 10 includes a traveling vehicle 12, a power supply station 14, and a management terminal 40, which is a management device. The traveling vehicle 12 and the management terminal 40 can communicate with each other via wireless communication, and the power supply station 14 and the management terminal 40 can communicate with each other via wired 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 receiving system 44, a battery 45, and a control device 46.

[0024] The drive unit 41 includes two motors that individually drive and rotate the two drive wheels 21.

[0025] The external sensor unit 42 includes the image acquisition unit 25, which is a camera, as well as an optical sensor or ultrasonic sensor that detects obstacles in the direction of movement and the distance to an object.

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

[0027] The power receiving system 44 is a power receiving device involved in charging the battery 45, and includes the power receiving pad 24 and the power receiving unit 47. The power receiving pad 24 receives power transmitted contactlessly from the power transmitting pad 34. The power receiving unit 47 converts the power received by the power receiving pad 24 into a predetermined charging power and charges the battery 45.

[0028] The battery 45 is a power source for 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 odometry unit 50, and a power receiving control unit 51. The drive control unit 48 controls each motor of the drive unit 41, i.e., controls the movement of the traveling vehicle 12. The odometry unit 50 calculates the amount of movement of the traveling vehicle 12 based on information from the internal sensor unit 43, and estimates the self-position and attitude of the traveling vehicle 12. The power receiving control unit 51 controls charging of the battery 45 by the power receiving system 44. The control device 46 is connected to the drive unit 41 and the image acquisition unit 25, and executes processing to output drive commands for the drive unit 41 and to transmit images captured by the image acquisition unit 25 to the management terminal 40.

[0030] The power supply station 14 also includes a power transmission system 53 and a marker 35. The power transmission system 53 is a power transmission side device involved in charging 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 receiving pad 24 in a contactless manner. The power transmission unit 54 converts the power and transmits it from the power transmission pad 34. The marker 35 includes a large marker 36 and a small marker 37.

[0031] The management terminal 40 also includes a work management unit 56, a map management unit 57, a traveling vehicle management unit 58, a power supply station management unit 59, and a travel trajectory generation unit 60. The work management unit 56 manages work information and work progress information for the traveling vehicles 12, work assignments to the traveling vehicles 12, and the like. The map management unit 57 manages the layout of each device on the floor of the facility as coordinate information. The traveling vehicle management unit 58 manages the work status of the traveling vehicles 12 and the remaining amount of power stored in the battery 45, and notifies the traveling vehicles 12 of the map coordinates of a destination point to which they should move when issuing work instructions. The power supply station management unit 59 manages the operating status of the power supply station 14.

[0032] The travel trajectory generation unit 60 performs image processing on an image of the marker 35 to recognize the relative position and orientation of the traveling vehicle 12 with respect to the marker 35. During a target movement operation in which the traveling vehicle 12 moves based on the marker 35 installed at the power supply station 14, which is the target point, the image acquisition unit 25 of the traveling vehicle 12, which is located away from the target point, acquires an image of the marker 35, performs image processing on the acquired image to recognize the relative position and orientation of the traveling vehicle 12 with respect to the marker 35, and generates a travel trajectory for the traveling vehicle 12 to move to the target point from the recognized relative orientation and relative position. Note that the travel trajectory generation unit 60 may be provided in the control device 46 of the traveling vehicle 12, and it is possible to appropriately select whether the travel trajectory generation unit 60 is provided on the edge side or on the cloud side. When the travel trajectory generation unit 60 is provided in the control device 46 of the traveling vehicle 12, the traveling vehicle 12 can independently perform the trajectory generation process. In addition, information processing can be arbitrarily allocated between the management terminal 40 and the control device 46, for example, by executing some processing on the management terminal 40 side and the remaining processing on the control device 46 of the traveling vehicle 12. Note that the traveling trajectory includes trajectories of various operations for traveling of the traveling vehicle 12, such as going straight, spinning, and curving, or trajectories that combine these. Furthermore, the traveling trajectory generated by the traveling trajectory generation unit 60 is the operation from the second operation step onwards, which will be described later.

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

[0034] The management terminal 40 assigns a task to the traveling vehicle 12 that is the task target, and the traveling vehicle 12 to which the task is assigned carries out the task, such as transporting the transported object.

[0035] The management terminal 40 monitors the remaining amount of power stored in the battery 45 of each traveling vehicle 12, and when it detects a traveling vehicle 12 whose remaining amount of power in the battery 45 falls below a reference value, it removes the traveling vehicle 12 from the work targets as a vehicle requiring charging, and reserves an available power supply station 14.

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

[0037] Upon receiving an instruction from the management terminal 40, the traveling vehicle 12 that needs to be charged executes a target movement operation to the power supply station 14, which is the target point. In this target movement operation, while moving to the power supply station 14, the traveling vehicle 12 temporarily stops at a position a short distance from the power supply station 14 (for example, about 1 m before) as a waypoint P1 (see FIG. 4(a)), searches for the marker 35 of the power supply station 14, and then moves toward the marker 35 of the power supply station 14. The waypoint P1 is a starting position where the traveling vehicle 12 starts a positioning operation, which is the final step of the target movement operation for autonomous movement to the target point.

[0038] As shown in Fig. 4(a), the traveling vehicle 12 temporarily stops at waypoint P1 on the way to the power supply station 14, and processes the image captured by the image capture unit 25 to search for the marker 35. After confirming the marker 35, the X and Y coordinates of the small marker 37 (or the large marker 36) relative to the origin 12a of the traveling vehicle 12 are acquired from the small marker 37. This process is called the first marker recognition step.

[0039] 4(b), the front surface 23 of the traveling vehicle 12 is directed toward the marker 35 of the power supply station 14, and the traveling vehicle 12 is caused to spin (turn on the spot) at the waypoint P1 so that the X-axis extending forward from the origin 12a of the traveling vehicle 12 coincides with the center of the marker 35 in the left-right direction, which serves as the reference position. This process is called the first operation step.

[0040] The images captured by the image acquisition unit 25 of the traveling vehicle 12 are sent to the management terminal 40, and the images are processed by the traveling trajectory generation unit 60 to recognize the relative orientation of the traveling vehicle 12 with respect to the large marker 36. This relative orientation is indicated by the relative yaw angle of the traveling vehicle 12, and can also be recognized as the angle θ between an imaginary vertical line 61 perpendicular to the center of the face of the large marker 36 and the X-axis direction extending forward of the traveling vehicle 12. Furthermore, the images captured by the image acquisition unit 25 of the traveling vehicle 12 are processed by the traveling trajectory generation unit 60 to recognize the relative position of the traveling vehicle 12 with respect to the small marker 37. This relative position is represented by the XY coordinates of the traveling vehicle 12 with respect to the small marker 37, with the Y coordinate value being 0. This process is called the second marker recognition step.

[0041] The relative position of the vehicle 12 may be recognized again from the small marker 37 after the vehicle 12 has finished spinning and the relative position may be updated, or the relative position may be continuously recognized from the small marker 37 while the vehicle 12 is spun and the relative position may be continuously updated.

[0042] In this case, since the traveling vehicle 12 located at the waypoint P1 is located a little distance from the power supply station 14, it is possible to recognize the relative position from the small marker 37 in the image captured by the image acquisition unit 25 of the traveling vehicle 12, but the relative attitude (angle θ) is recognized from the tilt of the small marker 37, etc., and the small marker 37 in the captured image may be too small and the recognition accuracy may be poor. On the other hand, the large marker 36 recognized in the image captured by the image acquisition unit 25 of the traveling vehicle 12 is larger than the small marker 37 in the captured image, and the relative attitude (angle θ) can be recognized with high accuracy from the tilt of the large marker 36, etc.

[0043] After recognizing the relative position and attitude of the power supply station 14 with respect to the marker 35, the running trajectory generation unit 60 generates a running trajectory that moves around from the via point P1 to the front of the marker 35 of the power supply station 14 and approaches it, and transmits the generated running trajectory to the traveling vehicle 12 to cause the traveling vehicle 12 to move along the running trajectory.

[0044] The travel trajectories include a first travel trajectory in which the origin 12a of the traveling vehicle 12 moves to an intermediate point P2 set on a virtual vertical line 61 that is perpendicular to the display surface of the marker 35 and extends from the center of the display surface, and a second travel trajectory in which the traveling vehicle 12 moves from the intermediate point P2 toward the marker 35 of the power supply station 14. The travel trajectory is a series of movements of the traveling vehicle 12 that combines straight-line travel and spin rotations of the traveling vehicle 12, and the spin angle and travel distance (straight-line distance) of the traveling vehicle 12 until it arrives at the intermediate point P2 are calculated from the tilt angle of the traveling vehicle 12 relative to the marker 35 and the distance (X coordinate) between the marker 35 and the traveling vehicle 12. Then, a travel trajectory of the traveling vehicle 12 is generated in which the traveling vehicle 12 transfers to the virtual vertical line 61 and turns around to face the marker 35 based on the tilt angle (relative yaw angle) of the traveling vehicle 12 relative to the large marker 36 and the XY coordinates of the small marker 37. This series of steps is called the trajectory generation step.

[0045] The intermediate point P2 set on the imaginary vertical line 61 is a point where an imaginary line extending from the origin 12a of the traveling vehicle 12 intersects at a right angle with the imaginary vertical line 61. Alternatively, the intermediate point P2 may be a point closer to the marker 35 of the power supply station 14 than the point where an imaginary line extending from the origin 12a of the traveling vehicle 12 intersects at a right angle with the imaginary vertical line 61, as long as the origin 12a of the traveling vehicle 12 can transfer from the via point P1 to the intermediate point P2.

[0046] 4(b), the traveling vehicle 12 facing the marker 35 is temporarily stopped for a predetermined time, and the image acquisition unit 25 is caused to capture images of the marker 35 multiple times. The traveling trajectory generation unit 60 then acquires the relative angle of the traveling vehicle 12 with respect to the marker 35 from the multiple captured images of the marker. The relative angle used to generate the trajectory is the median value of the relative angles acquired from the marker 35 in the multiple captured images, thereby improving the accuracy of positioning traveling.

[0047] 4(c) to 4(h) show the target movement operation of the traveling vehicle 12 along the travel trajectory to the target point, the power supply station 14. As shown in FIG. 4(c), the traveling vehicle 12 spins toward the waypoint P2, and then moves forward after the traveling direction of the traveling vehicle 12 faces the waypoint P2. As shown in FIG. 4(d), the traveling vehicle 12 stops temporarily when the origin 12a of the traveling vehicle 12 reaches the waypoint P2 on the imaginary vertical line 61. The process in FIG. 4(c) is called the second operation step, and the process in FIG. 4(d) is called the third operation step.

[0048] As shown in FIG. 4(e), the traveling vehicle 12 spins so that the front face 23 of the traveling vehicle 12 faces the marker 35 on the power supply station 14, and the traveling direction of the traveling vehicle 12 faces the marker 35. By facing the marker 35 on the power supply station 14, the image captured by the image acquisition unit 25 of the traveling vehicle 12 is processed to recognize the relative posture from the large marker 36 and the relative position from the small marker 37. The process in FIG. 4(e) is called the fourth operation step.

[0049] Here, when moving from the via point P1 to the intermediate point P2, instead of Figures 4(c) to (d), as shown in Figures 5(c) to (d), the traveling vehicle 12 may be spun so that its traveling direction is at a predetermined angle with respect to the imaginary vertical line 61, moved in a diagonal direction with respect to the imaginary vertical line 61, and then spun by the predetermined angle to change its traveling direction.

[0050] 4(c) to 4(e) and 5(c) to 5(e), the marker 35 may be out of the field of view of the image acquisition unit 25, and the traveling vehicle 12 can travel along the generated trajectory based on the odometry information of the internal sensor unit 43. Note that in the steps of FIGS. 4(c) to 4(e) and 5(c) to 5(e), the traveling vehicle 12 can also travel based on the travel distance and spin angle of the generated traveling trajectory, without using information on the relative position and relative attitude from the marker 35.

[0051] Furthermore, because the traveling vehicle 12 is located away from the power supply station 14, both the large marker 36 and the small 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 Figure 6(a). Both the large marker 36 and the small 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 marker 36 and the small marker 37 are recognized from this captured image.

[0052] 4(f) and 1(a), the traveling vehicle 12, facing the marker 35 of the power supply station 14, moves forward so as to approach the marker 35 of the power supply station 14. At this time, the traveling trajectory generation unit 60 processes the images captured by the image acquisition unit 25, and the traveling vehicle 12 moves forward while checking the relative attitude recognized from the large marker 36 and the relative position recognized from the small marker 37. If there is a deviation in the relative attitude with respect to the large marker 36, the traveling vehicle 12 moves forward while correcting the relative attitude of the traveling vehicle 12 with respect to the large marker 36 by individually controlling the rotation of the drive wheels 21 on both sides.

[0053] As shown in Figures 4(g) to (h) and Figure 1(c), when the traveling vehicle 12 approaches the marker 35 of the power supply station 14, the entire small marker 37 is included in the field of view 26 of the image acquisition unit 25, but a portion of the upper side of the large marker 36 is not included. Figure 6(b) shows the image captured by the image acquisition unit 25 at this time. The frame of the captured image corresponding to the field of view 26 of the image acquisition unit 25 includes the entire small marker 37, but a portion of the upper side of the large marker 36 is not included, so the large marker 36 is not recognized in this captured image, and only the small marker 37 is recognized.

[0054] Therefore, until just before, the traveling vehicle 12 had recognized the relative attitude of the large-sized marker 36 and was moving toward the marker 35 of the power supply station 14, but after the large-sized marker 36 is no longer recognized, the traveling vehicle 12 recognizes the relative attitude from the small-sized marker 37 and moves toward the marker 35 of the power supply station 14. Note that if relative attitude information is simultaneously acquired from both markers 36, 37, and if the large-sized marker 36 goes outside the field of view 26 of the image acquisition unit 25 and cannot be recognized, the relative attitude information acquired from the large-sized marker 36 is overwritten with the relative attitude information acquired from the small-sized marker 37 so that it becomes correct, then a change in the recognition target markers 36, 37 is also included in the case of changing the recognition target markers 36, 37.

[0055] At this time, the traveling vehicle 12 approaches the marker 35 of the power supply station 14, and since the small-sized marker 37 in the captured image taken by the image acquisition unit 25 is large, the relative posture can be recognized with high accuracy even from the small-sized marker 37.

[0056] Thereafter, when the traveling vehicle 12 determines from its relative position with respect to the small marker 37 that it has reached the target point, the power supply station 14, it stops moving. If the relative position and attitude of the traveling vehicle 12 with respect to the small marker 37 are normal, it determines that the power receiving pad 24 of the traveling vehicle 12 and the power transmission pad 34 of the power supply station 14 are facing each other with a predetermined distance between them, and the power transmission pad 34 of the power supply station 14 transmits power to the power receiving pad 24 of the traveling vehicle 12, thereby starting to charge the battery 45 of the traveling vehicle 12. The steps in Figures 4(f) to (h) are referred to as a fifth operation step.

[0057] If it is recognized between Figures 4(e) and 4(h) that the origin 12a of the vehicle 12 is not located on the virtual vertical line 61 but is shifted to the side, as shown in Figures 7(a) to 7(d), the vehicle 12 can be rotated sideways relative to the small marker 37, and then moved forward until the origin 12a of the vehicle 12 is placed on the virtual vertical line 61, and then rotated until the vehicle 12 is directly facing the small marker 37.

[0058] Furthermore, if there is an abnormality in the relative position and relative posture of the vehicle 12 with respect to the small marker 37, the vehicle 12 will first retreat to a predetermined retreat position and then perform the target movement operation again toward the power supply station 14, which is the destination point of the vehicle 12.

[0059] 8(a) to 8(f) show another example of a target movement motion in which the traveling vehicle 12 moves backward toward a target point.

[0060] As shown in Figures 8(a) to (d) (similar to Figures 4(a), 4(b), 5(c), and 5(d)), the traveling vehicle 12 moves to the intermediate point P1, recognizes the relative position and relative attitude between the traveling vehicle 12 and the marker 35, and then spins around so that the traveling direction of the traveling vehicle 12 faces the intermediate point P2, setting the intermediate point P2 to a point closer to the marker 35 than the point where a virtual line extending from the origin 12a of the traveling vehicle 12 intersects the virtual vertical line 61 at a right angle. The traveling vehicle 12 then moves forward toward the intermediate point P2 on the virtual vertical line 61, and when the origin 12a of the traveling vehicle 12 reaches the intermediate point P2 on the virtual vertical line 61, the traveling vehicle 12 comes to a temporary halt.

[0061] As shown in FIG. 8(e), at the intermediate point P2, the traveling vehicle 12 spins so that the front surface 23 of the traveling vehicle 12 faces away from the marker 35 at the destination point and the rear surface of the traveling vehicle 12 faces the marker 35.

[0062] As shown in Fig. 8(f), the traveling vehicle 12 moves backward from the waypoint P2 towards the marker 35 and approaches the marker 35. Although the traveling vehicle 12 moving backward cannot recognize the marker 35, the traveling vehicle 12 moves to the target point and stops based on the travel distance from the waypoint P2 of the generated traveling trajectory towards the marker 35.

[0063] 9(a) to 9(i) show, as yet another example of the target movement motion, a target movement motion in which the traveling vehicle 12 moves backward toward the target point.

[0064] 9(a) to 9(e) (similar to FIGS. 4(a) to 9(e)), the traveling vehicle 12 moves to the waypoint P1, recognizes the relative position and orientation between the traveling vehicle 12 and the marker 35, then spins so that the traveling direction of the traveling vehicle 12 faces the midpoint P2 at a right angle to the imaginary vertical line 61, moves forward toward the midpoint P2 on the imaginary vertical line 61, and stops when the origin 12a of the traveling vehicle 12 reaches the midpoint P2 on the imaginary vertical line 61. The traveling vehicle 12 spins so that the front surface 23 of the traveling vehicle 12 faces the marker 35 at the destination point.

[0065] In this case, if the distance from the intermediate point P2 to the marker 35 is relatively large and the traveling vehicle 12 moves backward from the intermediate point P2, the marker 35 cannot be photographed, which may result in a deviation in the position of the traveling vehicle 12 relative to the target point. Therefore, as shown in Fig. 9(f), the traveling vehicle 12 moves forward to a second intermediate point P3, which is closer to the marker 35 than the intermediate point P2, and stops there.

[0066] As shown in Figure 9(g), the vehicle 12 stops at the second intermediate point P3 and spins around 180 degrees so that the front 23 of the vehicle 12 faces away from the marker 35 at the destination point and the rear of the vehicle 12 faces the marker 35.

[0067] 9(h) to 9(i), the traveling vehicle 12 moves backward from the second way point P3 toward the marker 35 and approaches the marker 35. The traveling vehicle 12 moving backward cannot photograph the marker 35, but based on the travel distance from the second way point P3 to the marker 35 on the generated traveling trajectory, the traveling vehicle 12 moves backward and stops at the target point.

[0068] 10(a) to 10(h) show, as yet another example of the target movement operation, a target movement operation in which the towed object 70 is towed and moves backward toward the target point.

[0069] The towed object 70 is, for example, a car truck that can travel on a running surface such as a floor. The towed object 70 has a long loading platform 71 and multiple wheels arranged on the underside of the loading platform 71, at the center in the longitudinal direction and on both left and right ends. The center wheel is fixed in its rotational direction along the longitudinal direction of the loading platform 71, while the wheels on both ends are configured as casters that can change their direction of movement. The towed object 70 can travel in one direction or the other along the longitudinal direction (front-to-back direction) of the loading platform 71 and can turn on the spot with the center of the towed object 70 (between the wheels on both the left and right sides of the center) as the origin 70a. The origin 70a is the center of rotation of the towed object 70, the point at which the towed object 70 is located on the imaginary vertical line 61 of the marker 35 before turning, and the point at which the towed object 70 is located on the imaginary vertical line 61 of the marker 35 after turning. The dimensions of each part of the traveling vehicle 12 and the towed object 70 are stored in the control device 46 or the management terminal 40 as known information.

[0070] The travelling vehicle 12 is provided with an arm 73 that can rotate around the origin 12a. A rotation center is provided at the front end of the arm 73, and a connecting mechanism is provided at the rear end, which is the tip side of the arm 73, and the connecting mechanism is detachably connected to one end in the longitudinal direction of the loading platform 71 of the towed object 70.

[0071] The marker 35 is placed corresponding to the target area 75 to which the towing object 70 is to be moved. The center of the target area 75 is located on the imaginary vertical line 61 of the marker 35, and the relationship between the relative position and relative orientation of the marker 35 and the target area 75 is stored as known information in the management terminal 40. Fig. 10 shows an example in which three target areas 75 are lined up, and a marker 35 is placed corresponding to each target area 75, but for the purpose of explaining the operation, only one marker 35 is shown, and the others are not shown.

[0072] As shown in FIG. 10(a), the traveling vehicle 12 towing the towed object 70 moves to a way point P1 between the marker 35 and the target area 75 and stops there.

[0073] As shown in FIG. 10(b), the traveling vehicle 12 is made to spin (turn on the spot) at the waypoint P1 so that the X-axis extending forward from the origin 12a of the traveling vehicle 12 and the reference position of the marker 35 overlap.

[0074] The images captured by the image acquisition unit 25 of the traveling vehicle 12 are sent to the management terminal 40, and the traveling trajectory generation unit 60 of the management terminal 40 acquires and processes the captured images to recognize the relative position and orientation of the traveling vehicle 12 with respect to the marker 35. Based on this recognition, the traveling trajectory generation unit 60 calculates, as shown in FIG. 11 , the XY coordinates of the marker 35 in a traveling vehicle coordinate system based on the traveling vehicle 12, an angle θ which is the relative yaw angle between the X axis of the traveling vehicle 12 and a virtual vertical line 61 of the marker 35, The travel trajectory generating unit 60 recognizes the angle (90-θ) between the X-axis of the travelling vehicle 12 and a virtual line extending from the origin 12a of the travelling vehicle 12 and intersecting the virtual vertical line 61 at a right angle, the distance L1 between the origin 12a of the travelling vehicle 12 and the reference position of the marker 35, the distance L2 (known) between the origin 12a of the travelling vehicle 12 and the origin 70a of the towed object 70, and the distance L3 (L2+L1·sinθ) between the origin 70a of the towed object 70 and the virtual vertical line 61 of the marker 35. The travel trajectory generating unit 60 then generates a travel trajectory for moving the towed object 70 to the target area 75 by the movement of the travelling vehicle 12 from the via point P1, and transmits information about the generated travel trajectory to the travelling vehicle 12. Here, the travelling vehicle 12 moves from the via point P1 to point P4, which is beyond the virtual vertical line 61. Point P4, where the traveling vehicle 12 is positioned beyond the imaginary vertical line 61, is the point where the origin 12a of the traveling vehicle 12 is located on the imaginary vertical line 61 when the traveling vehicle 12 travels from point P4 along a 90-degree arc trajectory with a radius r. When the traveling vehicle 12 has finished moving to point P4, the towed object 70 will be located on the imaginary vertical line 61. The radius r is the distance between the origin 12a of the traveling vehicle 12 and the origin 70a of the towed object 70. In the case of FIGS. 10 and 11, the origin 12a of the traveling vehicle 12 and the origin 70a of the towed object 70 are located on the same straight line in the traveling direction of the traveling vehicle 12, so the radius r of the 90-degree arc trajectory is a distance L2. Therefore, the traveling vehicle 12 exceeds the imaginary vertical line 61 by the distance L2.

[0075] 10(c) to (h) show the target movement of the traveling vehicle 12 along the traveling trajectory. As shown in FIG. 10(c), upon receiving the information on the traveling trajectory, the traveling vehicle 12 spins by a predetermined angle (90-θ) so that its forward direction is perpendicular to the imaginary vertical line 61 of the marker 35.

[0076] As shown in FIG. 10(d), the traveling vehicle 12 moves forward, and when the origin 70a of the towed object 70 reaches the imaginary vertical line 61 of the marker 35 based on the recognized distance L3, the traveling vehicle 12 stops.

[0077] As shown in FIG. 10( e ), the traveling vehicle 12 spins by 90 degrees so that the traveling direction of the traveling vehicle 12 faces in the opposite direction to the target area 75 .

[0078] 10(f), the traveling vehicle 12 turns around the origin 70a of the towed object 70 and stops when the origin 12a of the traveling vehicle 12 reaches the imaginary vertical line 61 of the marker 35. In this state, the origin 12a, which is the center of the left and right of the traveling vehicle 12 in the straight-ahead direction, and the origin 70a, which is the center of the left and right of the towed object 70 in the straight-ahead direction, are located on the imaginary vertical line 61.

[0079] 10(g), the traveling vehicle 12 spins 90 degrees so that its forward direction faces the marker 35. In this state, the traveling vehicle 12 and the towed object 70 are aligned in the front-to-rear direction on an imaginary vertical line 61 of the marker 35.

[0080] As shown in FIG. 10(h), based on the information on the distance between the marker 35 and the target area 75, the traveling vehicle 12 moves backward, and moves the towed object 70 to the target area 75 and stops.

[0081] In addition, if there is no need to move the towed object 70 backward and the traveling vehicle 12 is to approach and stop at the marker 35, the traveling vehicle 12 can be stopped in the state shown in Figure 10(g) or after moving the traveling vehicle 12 further forward from Figure 10(g).

[0082] FIG. 12 shows the relationship between the traveling vehicle 12, the towing object 70, and the marker 35 in yet another example of the target movement operation when the towing object 70 is towed.

[0083] When the towed object 70 has wheels at its four corners that can freely change direction and is turned around one wheel, the position of that wheel offset from the center of the towed object 70 is determined as the turning center (origin 70a) of the towed object 70. Note that any predetermined position within the towed object 70 can be determined as the turning center in this manner.

[0084] When the turning center (origin 70a) of the towed object 70 is offset in this manner, the traveling vehicle 12 travels from the via point P1 to a predetermined point P4 beyond the virtual vertical line 61, and then the traveling vehicle 12 travels a predetermined angle on an arc trajectory whose radius is the distance between the turning center (origin 70a) of the towed object 70 and the turning center (origin 12a) of the arm 73, thereby generating a traveling trajectory such that the origin 12a of the traveling vehicle 12 is located on the virtual vertical line 61 of the marker 35.

[0085] The distance L11 from the via point P1 to the position of point P4 beyond the virtual vertical line 61 includes the calculated distance L12 from the via point P1 to the virtual vertical line 61 of the marker 35 and the known distance L13 from the virtual vertical line 61 to point P4 beyond the virtual vertical line 61.

[0086] Then, the traveling vehicle 12 travels by combining a spinning motion and a circular motion around the turning center 70a, so that the center of the traveling vehicle 12 is transferred to the imaginary center line 61. With the center of the traveling vehicle 12 positioned on this imaginary center line 61, the center of the towed object 70 is also positioned on the imaginary center line 61, so the traveling vehicle 12 and the towed object 70 are aligned in a straight line, and the traveling vehicle 12 can be moved forward or backward to move the towed object 70 toward the target point.

[0087] As described above, in this embodiment, the coordinates of the relative position of the traveling vehicle 12 with respect to the marker 35 and the tilt angle of the relative attitude (relative yaw angle) are recognized in the coordinate recognition step of the marker 35 and the angle recognition step with respect to the marker 35, and the traveling trajectory of the traveling vehicle 12 is generated based on the coordinates of the relative position and the tilt angle of the relative attitude, thereby improving the traveling accuracy. Furthermore, the traveling trajectory can be generated by spin rotation and straight traveling motion, and the traveling vehicle 12 can travel even if the marker 35 goes out of the field of view of the image acquisition unit 25 while turning around, and in addition, the reliability of internal information such as odometry can be ensured more than when the traveling vehicle 12 travels on a curved trajectory, improving the traveling accuracy of the traveling vehicle 12.

[0088] Furthermore, because the travel trajectory of the traveling vehicle 12 consists of spin rotations and straight travel, the travel trajectory can be made more compact than when the travel trajectory includes curved travel, and the waypoint 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 point is reduced, the operation for positioning can be started when the traveling vehicle 12 approaches the marker 35, so the marker 35 can be photographed at a certain size or larger within the field of view of the image acquisition unit 25, improving the degree of freedom in installing the marker 35.

[0089] Furthermore, the relative yaw angle of the vehicle 12 relative to the marker 35 is recognized after the vehicle 12 is spun so that the X-axis direction of the vehicle 12 overlaps with the reference position of the marker 35, which increases the reliability of the relative yaw angle.Furthermore, the accuracy of the recognition of the relative yaw angle is improved by using the median value of the relative yaw angles obtained from images of multiple markers 35, which results in an improvement in the accuracy of the trajectory generated using the relative yaw angle.

[0090] The stopping station 13 is not limited to the power supply station 14, but may be a source station where the transported goods are received to be loaded onto the traveling vehicle 12 or where the towed goods are coupled to the traveling vehicle 12, or a destination station where the transported goods are removed from the traveling vehicle 12 or where the towed goods are detached from the traveling vehicle 12.

[0091] In the first to fifth operation steps, the traveling vehicle 12 can be made to travel by performing various traveling operations such as going straight, turning, spinning, etc., or by a combination of these.

[0092] Although the embodiment of the present invention and its modified examples have been described above, various combinations of configurations, partial omissions, substitutions and modifications are also possible. [Explanation of symbols]

[0093] 12 Traveling vehicles 20 Main body 25 Image acquisition unit 35 Marker 41 Drive unit 60 Travel trajectory generation unit 61 Virtual Vertical Line 73 Arm P1 via point (starting position) P2 Midpoint

Claims

1. A traveling vehicle system that generates a traveling trajectory for autonomously traveling a traveling vehicle to a target point, the traveling vehicle having a main body, a drive unit that is installed on the main body and causes the main body to travel, and an image acquisition unit that is installed on the main body and captures an image of an external environment of the main body, a travel trajectory generation unit that generates a travel trajectory for the traveling vehicle to travel to the target point based on a marker installed corresponding to the target point photographed by the image acquisition unit, The running trajectory generation unit At a start position where the traveling vehicle is located away from the target point, image processing is performed on the image of the marker taken by the image acquisition unit to recognize the relative position between the marker and the traveling vehicle, and image processing is performed on the image of the marker taken by the image acquisition unit of the traveling vehicle that has traveled in a state facing a reference position of the marker based on the relative position to recognize the relative position and relative attitude between the marker and the traveling vehicle, Based on the relative positions and the relative orientations between the marker and the traveling vehicle, a travel trajectory is generated for the traveling vehicle to travel to a position where the front of the marker faces the traveling direction of the traveling vehicle. A traveling vehicle system characterized by:

2. The running trajectory generation unit The relative position is recognized by the coordinates of the position of the marker in a traveling vehicle coordinate system with the traveling vehicle as the origin; The relative attitude is recognized as a relative yaw angle of the traveling vehicle with respect to a display surface of the marker when the traveling direction of the traveling vehicle is facing the reference position of the marker.

2. The traveling vehicle system according to claim 1.

3. a main body; a drive unit that is installed on the main body and drives the main body; an image acquisition unit that is installed in the main body and captures an image of the outside world of the main body; an autonomous driving method for causing a traveling vehicle to travel to a target point corresponding to a marker based on a traveling trajectory generated by a traveling trajectory generating unit, a first marker recognition step of recognizing, from an image of the marker captured by the image acquisition unit at a start position where the traveling vehicle is located away from the target point, XY coordinates of the marker in a traveling vehicle coordinate system in which the straight traveling direction of the traveling vehicle is defined as an X axis and a direction perpendicular to the X axis is defined as a Y axis; a first operation step of driving the traveling vehicle by the drive unit until an X axis of the traveling vehicle overlaps with a reference position of the marker; a second marker recognition step of recognizing a relative yaw angle of the traveling vehicle with respect to the marker from an image of the marker captured by the image acquisition unit after the first operation step; and a trajectory generation step of generating a travel trajectory for the traveling vehicle to transfer to an intermediate point located away from the marker on a virtual vertical line that is perpendicular to the display surface of the marker and extends from a reference position of the marker, based on the XY coordinates and the relative yaw angle of the marker after the first operation step. An autonomous driving method characterized by:

4. In the trajectory generation step, a spin angle for spinning the traveling vehicle until the X axis of the traveling vehicle overlaps with the midpoint is generated as a second operation step, a travel distance for moving the traveling vehicle straight until it reaches the midpoint is generated as a third operation step, and a spin angle for spinning the traveling vehicle that has arrived at the midpoint so that it faces the reference position of the marker is generated as a fourth operation step.

4. The autonomous driving method according to claim 3.

5. the origin of the travelling vehicle coordinate system is located at the center of spin rotation of the travelling vehicle, the first operation step is an operation of spinning the traveling vehicle, spin angles in the first operation step, the second operation step, and the fourth operation step are rotation angles based on the origin; The travel distance in the third operation step is the distance until the origin overlaps with the intermediate point.

5. The autonomous driving method according to claim 4.

6. In the step of driving the traveling vehicle based on the trajectory generation step, the driving unit is driven based on the traveling distance and the spin angle of the generated traveling trajectory without using information recognized from the markers.

6. The autonomous driving method according to claim 5.

7. An autonomous driving method for autonomously driving a traveling vehicle having a main body, a drive unit installed on the main body and driving the main body, and an image acquisition unit installed on the main body and capturing an image of an external environment of the main body to a target point corresponding to a marker, a first marker recognition step of acquiring a relative position between the marker and the traveling vehicle by performing image processing on an image of the marker captured by the image acquisition unit at a start position where the traveling vehicle is located away from the target point; a first operation step of operating the traveling vehicle so as to face a reference position of the marker based on the relative position recognized in the first marker recognition step; a second marker recognition step of recognizing the relative position and relative attitude between the marker and the traveling vehicle facing a reference position of the marker after the first operation step; a trajectory generation step of generating a travel trajectory for the traveling vehicle facing the reference position of the marker to travel to a position facing directly in front of the marker, based on the relative position and the relative attitude between the marker recognized in the second marker recognition step and the traveling vehicle facing the reference position of the marker; An autonomous driving method comprising:

8. An autonomous driving method for autonomously driving a traveling vehicle towing a towing object to a target point corresponding to a marker, the method comprising: a main body; a drive unit installed on the main body and driving the main body; an image acquisition unit installed on the main body and capturing an image of the outside world of the main body; and an arm installed rotatably with respect to the main body and to which a towing object is connected, the traveling vehicle towing the towing object comprising: a step of recognizing a relative position and a relative attitude of the traveling vehicle with respect to the marker at a starting position where the traveling vehicle is away from the target point and the marker; a trajectory generation step of generating a travel trajectory for the traveling vehicle to transfer onto a virtual vertical line extending from a reference position of the marker, based on the recognized relative position and relative attitude; In the trajectory generation step, After the traveling vehicle travels from the starting position to a position beyond the virtual vertical line, the traveling vehicle travels a predetermined angle along an arcuate path having a radius equal to the distance between the center of rotation defined within the towed object and the center of rotation of the arm, thereby generating a traveling path such that the traveling vehicle is positioned on the virtual vertical line of the marker. An autonomous driving method characterized by:

Images