JP7498348B1 - Vehicle and autonomous driving method - Google Patents

Abstract

A traveling vehicle with improved accuracy in autonomously moving to a target location is provided.
[Solution] At a start position where the traveling vehicle 12 is located away from a target point, image processing is performed on an image of a marker 35 captured by an image capture unit to recognize the relative positional relationship between the traveling vehicle 12 and the marker 35. Based on the relative positional relationship, the traveling vehicle 12 is spun on the spot so that the traveling direction of the traveling vehicle 12 faces the reference position of the marker 35. Image processing is performed on an image of the marker 35 captured with the traveling direction of the traveling vehicle 12 facing the reference position of the marker 35 to recognize the relative attitude relationship between the marker 35 and the traveling vehicle 12. Based on the relative position and relative attitude with the traveling direction of the traveling vehicle 12 facing the reference position of the marker 35, a traveling trajectory is generated to move the traveling vehicle 12 from the start position to a position where the traveling direction of the traveling vehicle 12 faces the front of the marker 35.
[Selected Figure] Figure 4

Description

The present invention relates to a vehicle that autonomously moves to a target point, and an autonomous driving method for making a vehicle that autonomously moves to a target point reach the target point.

As described in Patent Document 1, for example, a technology is known in which a camera installed on a traveling vehicle such as a robot captures an image of a marker installed at a target point, recognizes the relative position and orientation of the traveling vehicle with respect to the marker, generates a traveling trajectory of the traveling vehicle from the recognized relative position and orientation, and drives the traveling vehicle toward the target point.

JP 2015-121928 A

The above-mentioned technology requires autonomous vehicles to reach their destinations with high accuracy.

The present invention aims to provide a vehicle and an autonomous driving method that improves the accuracy of autonomous movement to a target location.

The traveling vehicle of the present invention is a traveling vehicle that moves autonomously to a target point, and includes a main body, a drive unit that is installed on the main body and moves the main body, an image acquisition unit that is installed on the main body and captures an image of the outside world of the main body, and a control device that is connected to the drive unit and the image acquisition unit and that outputs a drive command to the drive unit and executes image processing of the image acquired by the image acquisition unit, and the control device performs image processing on the 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 in a target movement operation that moves the traveling vehicle based on a marker installed corresponding to the target point. After recognizing the relative positional relationship between the running vehicle and the marker, the running vehicle is spun on the spot so that the running direction of the running vehicle faces the reference position of the marker based on the relative positional relationship, and then image processing is performed on the image of the marker taken with the running direction of the running vehicle facing the reference position of the marker to recognize the relative attitude relationship between the marker and the running vehicle, and a running trajectory is generated for moving the running vehicle from the starting position to a position where the front of the marker faces the running direction of the running vehicle based on the relative position and relative attitude in the state where the running direction of the running vehicle faces the reference position of the marker.

The present invention provides a vehicle and an autonomous driving method that improves the accuracy of autonomous movement to a target location.

1A and 1B show an embodiment of the traveling vehicle system of the present invention, in which FIG. 1A is a side view of a traveling vehicle positioned away from a power supply station, FIG. 1B is a front view of the power supply station, and FIG. 1C is a side view of a traveling vehicle approaching the power supply station. FIG. 4 is a front view of a marker installed in the power supply station. FIG. 2 is a block diagram of the traveling vehicle system. 5A to 5H are explanatory diagrams showing a target movement operation of the traveling vehicle to a power supply station. 11(c) to 11(e) are explanatory diagrams showing other examples of the target movement operation of the traveling vehicle to the power supply station. 13A and 13B show images captured by an image acquisition unit of the traveling vehicle, in which (a) is an explanatory diagram of an image captured when the traveling vehicle is located away from a power supply station, and (b) is an explanatory diagram of an image captured when the traveling vehicle is approaching the power supply station. 13A to 13D 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.

One embodiment of the present invention will be described below with reference to Figures 1 to 5.

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

The traveling vehicle 12 includes, for example, an automated guided vehicle that carries an object to be transported or tows an object such as a car truck or a dolly, and transports the object from a specified source to a destination. Furthermore, the traveling vehicle system 10 includes a power supply station 14, which is one of the stop stations 13 and serves 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.

The traveling vehicle 12 is equipped with a main body 20, a pair of drive wheels 21 and a number of driven wheels 22 that move the main body 20. The traveling vehicle 12 has one direction as a forward direction and the other direction as a reverse direction, and two drive wheels 21 are installed on both sides of the left and right direction that intersect with the forward and reverse directions, and driven wheels 22 are installed in the front and rear directions of the drive wheels 21 on both sides. The drive wheels 21 on both sides can be rotated independently in the forward and reverse directions, and the driven wheels 22 are composed of casters or the like that can freely change the direction of movement. 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 a fixed position), and other movements.

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.

The power receiving pad 24 is capable of receiving 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 that is compatible with the electromagnetic induction method.

The image acquisition unit 25 is a camera that captures the external environment in front of the traveling vehicle 12, and has a predetermined field of view 26 in the vertical and horizontal directions (FIGS. 5(a) and (b) show captured images corresponding to the field of view 26). The image acquisition unit 25 is installed in the main body 20 so that the lower end (bottom side) of the range of the vertical viewing angle α in the field of view 26 is positioned approximately horizontally, and the center line 27 of the vertical viewing angle α in the field of view 26 faces upward.

The power supply station 14 supplies power to charge the battery of the traveling vehicle 12. The power supply station 14 has a housing 30 installed on the floor surface 11. A facing surface 31 is formed on the front side of the housing 30, 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. A facing convex surface 32 that faces closely to the main body 20 located at the power supply station 14 is formed on the upper side of this 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 on the lower side of the facing surface 31.

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

The power transmission pad 34 can transmit power using 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 the shape of a pad with a built-in power transmission coil compatible with the electromagnetic induction method. 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 in which 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.

1 and 2, the marker 35 is an AR marker with, for example, a figure, pattern, etc. displayed on the display surface of the marker 35, and has a large marker 36 and a small marker 37. The large marker 36 is arranged on the upper side of the facing concave surface 33, and the small marker 37 is arranged on the lower side of the facing concave surface 33, and these markers 36, 37 are 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 formed in a rectangular shape, and the centers of the large marker 36 and the small marker 37 are positioned on the same vertical axis and are provided on 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 positioned on the same vertical axis. The large marker 36 is formed in a rectangular shape with one side of, for example, 80 mm, and the small marker 37 is formed in a rectangular shape with one side of, for example, 30 mm.

Each marker 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, information on the relative attitude (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 horizontal direction of the X-axis and Y-axis) between the large-sized marker 36 and the small-sized marker 37 and the traveling vehicle 12 can be obtained. As shown in FIG. 4, the relative position of the traveling vehicle 12 is an XY coordinate of a traveling vehicle coordinate system in which the straight forward direction of the traveling vehicle 12 is the X-axis direction and the direction intersecting with the X-axis direction is the Y-axis direction with respect to the origin 12a, which is the center of the traveling vehicle 12 (center of spin rotation (turning on the spot)), as viewed from above the traveling vehicle 12. In addition, the relative attitude of the traveling vehicle 12 is indicated by the tilt angle of the X-axis of the traveling vehicle 12 with respect to each marker 36, 37 (the rotation angle of the 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.

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 so that the bottom end of the small marker 37 is located near the bottom end of the vertical viewing angle α in the field of view 26, and the center line 27 of the vertical viewing angle α in the field of view 26 faces upward. Furthermore, when the traveling vehicle 12 is located at the power supply station 14, which is the target point, the field of view 26 of the image acquisition unit 25 includes the entire small marker 37, and does not include part or all of the large marker 36. Also, when the traveling vehicle 12 is located at the power supply station 14, which is the target point, and the main body 20 of the traveling vehicle 12 is closely opposed to the facing convex surface 32 of the stopping station 14, the small marker 37 of the facing concave surface 33 is located farther than the minimum shooting distance of the image acquisition unit 25, and the small marker 37 can be photographed (focused) by the image acquisition unit 25.

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, 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 communication or wireless communication.

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.

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

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

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.

The power receiving system 44 is a power receiving device involved in charging the battery 45, and includes a power receiving pad 24 and a 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 specified charging power and charges the battery 45.

The battery 45 is the power source for the traveling vehicle 12 and supplies power to each electrical device equipped on the traveling vehicle 12.

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, i.e., controls the movement of the traveling vehicle 12. The image processing unit 49 performs image processing on the images of the markers 36, 37, and recognizes the relative position and orientation of the traveling vehicle 12 with respect to the markers 36, 37. 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 orientation of the traveling vehicle 12. The power receiving control unit 51 controls the 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 output of drive commands for the drive unit 41 and image processing of images acquired by the image acquisition unit 25. Furthermore, in a target movement operation in which the traveling vehicle 12 moves based on the large-sized marker 36 and the small-sized marker 37 installed at the power supply station 14, which is the target point, the control device 46 executes image processing on the images captured by the image acquisition unit 25 of the traveling vehicle 12 located away from the target point of the large-sized marker 36 and the small-sized marker 37 to recognize the relative attitude of the traveling vehicle 12 with respect to the large-sized marker 36 and the relative position of the traveling vehicle 12 with respect to the small-sized marker 37, and generates 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 travel path, and when the traveling vehicle 12 approaches the target point, performs image processing on the captured image of the small-sized marker 37 to recognize the relative position and relative attitude of the traveling vehicle 12 based on the small-sized marker 37. At this time, while the traveling vehicle 12 is moving to the target point, the marker to be recognized is changed so that the recognition of the relative attitude of the traveling vehicle 12 is based on the small-sized marker 37 instead of the large-sized marker 36.

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 non-contact 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.

The management terminal 40 also 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 work information and work progress information for the traveling vehicles 12, work allocation 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 power stored in the battery 45, and notifies the traveling vehicles 12 of the map coordinates of the target point to which they should move when issuing work instructions to the traveling vehicles 12. The power supply station management unit 59 manages the operating status of the power supply station 14.

Next, the operation of the traveling vehicle system 10 will be explained.

The management terminal 40 assigns tasks to the target traveling vehicles 12, and the traveling vehicles 12 to which the tasks are assigned carry out the tasks, such as transporting the goods.

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

The management terminal 40 instructs the vehicle 12 requiring charging to move to the reserved power supply station 14.

The traveling vehicle 12 that needs to be charged, which has received instructions from the management terminal 40, executes a target movement operation to the target point, the power supply station 14. In this target movement operation, while moving to the power supply station 14, the traveling vehicle stops temporarily at a position a short distance away from the power supply station 14 (e.g., about 1 m in front) as a waypoint P1 (see FIG. 4(a)), searches for the markers 36, 37 of the power supply station 14, and then moves toward the markers 36, 37 of the power supply station 14. The waypoint P1 is the 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 position.

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 the image captured by the image capture unit 25 is processed to search for the markers 36, 37. After the markers 36, 37 are confirmed, the XY coordinates of the small marker 37 relative to the origin 12a of the traveling vehicle 12 are obtained from the small marker 37 (or the large marker 36). This process is called the first marker placement recognition step.

As shown in FIG. 4(b), the front surface 23 of the traveling vehicle 12 is oriented toward the markers 36, 37 of the power supply station 14, and the traveling vehicle 12 is spun (turned on the spot) at the waypoint P1 so that the X-axis extending forward from the origin 12a of the traveling vehicle 12 overlaps with the center of the markers 36, 37 in the left-right direction as the reference position. This process is called the first spin step.

The 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 large marker 36. This relative position is indicated by the relative yaw angle of the traveling vehicle, and can also be recognized as the angle θ between a virtual vertical line 61 perpendicular to the center of the surface of the large marker 36 and the X-axis direction extending forward of the traveling vehicle 12. Furthermore, the 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 marker 37. This relative position is the XY coordinate of the traveling vehicle 12 with respect to the small marker 37, and the value of the Y coordinate is 0. This process is called the second marker recognition step. In addition, the recognition of the relative position of the traveling vehicle 12 may be performed by recognizing it from the small marker 37 again after the spin rotation of the traveling vehicle 12 is completed, and the relative position may be updated, or the traveling vehicle 12 may be spun while continuing to recognize the relative position from the small marker 37 and continue to update the relative position.

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 captured image taken by the image acquisition unit 25 of the traveling vehicle 12. However, since the relative attitude (angle θ) is recognized from the inclination of the small marker 37, 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 from the captured image taken 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 inclination of the large marker 36.

After recognizing the relative posture and relative device of the markers 36 and 37 of the power supply station 14, the traveling vehicle 12 generates a traveling trajectory that moves around from the waypoint P1 to the front of the markers 36 and 37 of the power supply station 14 and approaches them, and moves along the traveling trajectory.

The travel trajectory includes a first travel 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 travel trajectory that moves the traveling vehicle 12 from the intermediate point P2 toward the markers 36 and 37 of the power supply station 14. The travel trajectory is a series of movements of the traveling vehicle 12 that combines straight-line driving and spin rotation 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 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 in front of 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 process is called the trajectory generation step.

The intermediate point P2 set on the imaginary vertical line 61 is a point where a virtual line extending from the origin 12a of the traveling vehicle 12 intersects the imaginary 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 a virtual line extending from the origin 12a of the traveling vehicle 12 intersects the imaginary vertical line 61 at a right angle, and it is sufficient that the origin 12a of the traveling vehicle 12 can move from the via point P1 to the intermediate point P2, and it is sufficient that the origin 12a of the traveling vehicle 12 can move from the via point P1 to the intermediate point P2.

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 caused to capture images of the marker 35 multiple times. The relative angle of the traveling vehicle 12 with respect to the marker 35 is then acquired 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 travel.

Figures 4(c) to (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 Figure 4(c), the traveling vehicle 12 spins toward the midpoint P2, and moves forward after the traveling direction of the traveling vehicle 12 faces the midpoint P2. As shown in Figure 4(d), when the origin 12a of the traveling vehicle 12 reaches the midpoint P2 on the imaginary vertical line 61, the traveling vehicle 12 stops temporarily. The process in Figure 4(c) is called the second spin step, and the process in Figure 4(d) is called the transfer step.

As shown in FIG. 4(e), the traveling vehicle 12 spins 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 faces the markers 36, 37. By facing the markers 36, 37 of 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 third spin step.

When moving from via point P1 to intermediate point P2, instead of Figs. 4(c)-(d), the vehicle 12 may be spun so that its traveling direction is oriented at a predetermined angle with respect to the imaginary vertical line 61, as shown in Figs. 5(c)-(d), and then moved diagonally with respect to the imaginary vertical line 61, and then spun by a predetermined angle to change its traveling direction, as shown in Fig. 4(e).

In addition, in the steps of Fig. 4(c)-(e) and Fig. 5(c)-(d), the markers 36, 37 may be out of the field of view of the image acquisition unit 25, and the vehicle 12 can travel along the generated trajectory based on the odometry information of the internal sensor 43. Note that in the steps of Fig. 4(c)-(e), the vehicle 12 can also travel based on the travel distance and spin angle of the generated travel trajectory, without using information on the relative position and relative attitude from the markers 36, 37.

In addition, since 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 captured 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.

Next, as shown in FIG. 4(f) and FIG. 1(a), the traveling vehicle 12 facing the markers 36, 37 of the power supply station 14 moves forward so as to approach the markers 36, 37 of the power supply station 14. At this time, the traveling vehicle 12 performs image processing on the image captured by the image acquisition unit 25, and 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 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 marker 36 as it moves forward.

As shown in Figures 4(g) and 1(c), as the traveling vehicle 12 approaches the markers 36, 37 of the power supply station 14, the field of view 26 of the image acquisition unit 25 includes the entire small marker 37, but excludes a portion of the upper side of the large marker 36. 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 excludes a portion of the upper side of the large marker 36, so that the large marker 36 is not recognized from this captured image, and only the small marker 37 is recognized.

Therefore, until just before, the traveling vehicle 12 recognized the relative attitude of the large-sized marker 36 and moved toward the markers 36, 37 of the power supply station 14, but after the large-sized marker 36 is no longer recognized, it recognizes the relative attitude from the small-sized marker 37 and moves toward the markers 36, 37 of the power supply station 14. Note that the relative attitude information is acquired simultaneously from both markers 36, 37, and when the large-sized marker 36 goes out of the field of view of the image acquisition unit 25 and cannot be recognized, the relative attitude information acquired from the large-sized marker 37 is overwritten to make the relative attitude information acquired from the small-sized marker 37 correct. This also includes the case where the recognition target is transferred between the markers 36, 37 and the markers 36, 37 to be recognized as being changed.

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

Then, when the traveling vehicle 12 determines that it has reached the target point, the power supply station 14, based on its relative position with respect to the small marker 37, 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, starting charging the battery 45 of the traveling vehicle 12. The process from (e) to (h) in Figure 4 is called the approach travel step.

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

In addition, if there is an abnormality in the relative position and attitude of the traveling vehicle 12 with respect to the small marker 37, the traveling vehicle 12 will once retreat to a specified retreat position and then perform the target movement operation again toward the power supply station 14, which is the destination point of the traveling vehicle 12.

In this way, 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 marker 35 coordinate recognition step 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 traveling is possible even if the marker 35 goes out of the field of view of the image acquisition unit 25 while the traveling vehicle 12 is turning around. In addition, the reliability of internal information such as odometry can be ensured more than when traveling on a curved trajectory, improving the traveling accuracy of the traveling vehicle 12.

In addition, because the travel trajectory of the traveling vehicle 12 is made up of spin rotations and straight-ahead driving, the travel trajectory can be made more compact than when the travel trajectory includes curved driving, 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 position is reduced, the positioning operation can be started when the traveling vehicle 12 is close to 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.

In addition, the relative yaw angle of the vehicle 12 with respect 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, so the reliability of the relative yaw angle is increased. 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 improved accuracy of the trajectory generated using the relative yaw angle.

The stopping station 13 is not limited to the power supply station 14, but may be a source station that receives the transported goods to be loaded onto the traveling vehicle 12 or connects the towed goods to the traveling vehicle 12, or a destination station that removes the transported goods from the traveling vehicle 12 or detaches the towed goods from the traveling vehicle 12.

The above describes the embodiment of the present invention and its modified examples, but various combinations of configurations, partial omissions, substitutions, and modifications are also possible.

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 Midpoint

Claims (7)

A vehicle that moves autonomously to a destination,
A main body portion,
A drive unit that is installed on the main body and moves 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;
a control device connected to the driving unit and the image acquisition unit, and configured to output a driving command to the driving unit and to execute image processing of the image acquired by the image acquisition unit;
The control device includes:
In a target moving operation in which the traveling vehicle is moved based on a marker installed corresponding to the target point,
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 captured by the image capture unit to recognize the relative positional relationship between the traveling vehicle and the marker, and then the traveling vehicle is caused to spin around on the spot so that the traveling direction of the traveling vehicle faces the reference position of the marker based on the relative positional relationship, and then image processing is performed on the image of the marker captured with the traveling direction of the traveling vehicle facing the reference position of the marker to recognize the relative attitude relationship between the marker and the traveling vehicle;
a travel trajectory for moving the traveling vehicle from the starting position to a position where the traveling direction of the traveling vehicle faces the front of the marker, based on the relative position and the relative attitude in a state where the traveling direction of the traveling vehicle faces a reference position of the marker. The control device includes:
The traveling vehicle according to claim 1, characterized in that after the traveling direction of the traveling vehicle is oriented toward a reference position of the marker, the traveling vehicle is stopped and the image acquisition unit is caused to photograph the marker multiple times to obtain multiple images of the marker, and the relative attitude is determined from a median value of multiple pieces of relative attitude information obtained by image processing of each of the multiple images of the marker. The control device includes:
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;
3. The traveling vehicle according to claim 1, wherein the relative attitude is recognized as a relative yaw angle of the traveling vehicle with respect to a display surface of the marker in a state in which the traveling direction of the traveling vehicle is oriented toward a reference position of the marker. A main body portion,
A drive unit that is installed on the main body and moves 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;
a control device connected to the drive unit and the image acquisition unit, the control device outputting a drive command to the drive unit and executing image processing for a marker in an image acquired by the image acquisition unit, and moving the traveling vehicle to a target point corresponding to the marker,
The control device
a first marker recognition step of recognizing, from an image of the marker captured by the image acquisition unit of the traveling vehicle at a start position where the traveling vehicle is located away from the target point, an XY coordinate of the marker in a traveling vehicle coordinate system having an X axis in a straight traveling direction of the traveling vehicle and a Y axis in a direction perpendicular to the X axis;
a first spin step of spinning the traveling vehicle on the spot by the driving 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 the image of the marker acquired by the image acquisition unit after the first spin step;
and a trajectory generation step of generating a driving 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 X and Y coordinates of the marker after the first spin step and the relative yaw angle. 5. The autonomous driving method according to claim 4, wherein in the trajectory generation step, a spin angle of a second spin step in which the traveling vehicle is caused to spin and rotate until an X-axis of the traveling vehicle overlaps with the midpoint, a travel distance of a transfer step in which the traveling vehicle moves straight until it reaches the midpoint, and a spin angle of a third spin step in which the traveling vehicle that has arrived at the midpoint is caused to spin and rotate so that it faces a reference position of the marker are generated. the origin of the vehicle coordinate system is located at the center of spin rotation of the 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,
The autonomous driving method according to claim 5 , wherein the travel distance in the transfer step is a distance until the origin overlaps with the intermediate point. The autonomous driving method according to claim 5, characterized in that, in the step of driving the vehicle based on the trajectory generation step, the drive unit is driven based on the travel distance and the spin angle of the generated travel trajectory without using information recognized from the markers.

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