Autonomous mobile robot

Abstract

There is a need for autonomous robots that can ensure high positional accuracy while being easy to maintain. [Solution] The autonomous mobile robot according to this embodiment comprises a robot body, a distance sensor provided on the robot body, a front camera for photographing the area in front of the robot body, a rear camera for photographing the area below the robot body, a movement mechanism for moving the robot body, a setting unit for setting the movement mode of the robot body, and a control unit for controlling the movement mechanism in the set movement mode. The setting unit sets one of the following modes as the movement mode: an autonomous driving mode in which the robot autonomously travels along a predetermined route based on the output of the distance sensor, a line following mode in which the robot moves along line-shaped markers laid on the floor based on the output of the front camera, and a positioning mode in which the robot adjusts its position and attitude to a target position and attitude based on a two-dimensional code marker laid on the floor along the line-shaped markers based on the output of the rear camera.

Description

Technical Field

[0001] Embodiments of the present invention relate to an autonomous mobile robot.

Background Art

[0002] In recent years, with the evolution of robot arm technology, mobile robots are increasingly being adopted as means for transporting articles in factories, warehouses, and the like. For example, as a movement method of a mobile robot, there are a SLAM method (Simultaneous Localization and Mapping) that uses LiDAR or a camera to grasp its own position in real time and move to a target position, a line method that moves along a line-shaped marker laid along the movement path of the mobile robot using a sensor such as a camera, and a marker method that uses a sensor such as a camera to detect a marker provided on the floor surface and moves to a target position corresponding to the marker. The SLAM method does not require a specific guide like the line method or the marker method described below and can flexibly respond to various environmental changes. However, for operations that require high positioning accuracy such as docking at a charging station, the movement time until moving to the target position may become long, or in some cases, it may not be possible to move to the target position with high accuracy in the first place. The line method is a method for moving along a line-shaped marker provided on the floor surface or the like. In order to stop at the target position, a marker such as a command tape that can be detected by a camera is separately required on the floor surface. In addition, the work of laying line-shaped markers on the entire floor surface is a huge task, and a lot of labor is also required for the maintenance of the line-shaped markers. The marker method can move to an arbitrary target position and target posture based on the marker. However, the work of laying markers that require accuracy of the attachment position on the entire floor surface is a huge task, and a lot of labor is also required for the maintenance of the markers. Thus, when the SLAM method is adopted, ensuring positioning accuracy at the target position becomes an issue, and when the line method or the marker method is adopted, a lot of labor is required for the work of installing markers on the floor surface or the like and the maintenance work of the markers installed on the floor surface.

Summary of the Invention

[0003] There is a need for a mobile robot that is easy to maintain while ensuring high positioning accuracy. [Means for solving the problem]

[0004] The autonomous mobile robot according to this embodiment comprises a robot body, a distance sensor provided on the robot body, a front camera for photographing the area in front of the robot body, a rear camera for photographing the area below the robot body, a movement mechanism for moving the robot body, a setting unit for setting the movement mode of the robot body, and a control unit for controlling the movement mechanism in the set movement mode. The setting unit sets one of the following modes as the movement mode: an autonomous driving mode in which the robot autonomously travels along a predetermined route based on the output of the distance sensor, a line following mode in which the robot moves along line-shaped markers laid on the floor based on the output of the front camera, and a positioning mode in which the robot adjusts its position and attitude to a target position and attitude based on a two-dimensional code marker laid on the floor along the line-shaped markers based on the output of the rear camera. [Brief explanation of the drawing]

[0005] [Figure 1] Figure 1 is an overhead view of a factory in which the autonomous mobile robot according to this embodiment is used. [Figure 2] Figure 2 is a side view of the autonomous robot shown in Figure 1. [Figure 3] Figure 3 is a hardware configuration diagram of the autonomous robot shown in Figure 1. [Figure 4] Figure 4 shows an example of a label information management table stored in the server device 6 shown in Figure 3. [Figure 5] Figure 5 shows an example of a task sequence stored in the server device 6 shown in Figure 3. [Figure 6] Figure 6 shows an example of a charging information management table stored in the server device 6 shown in Figure 3. [Figure 7] Figure 7 is a functional configuration diagram of the autonomous mobile robot shown in Figure 1. [Figure 8] Figure 8 is a flowchart showing an example of the operation overview of the autonomous mobile robot according to this embodiment. [Figure 9] Figure 9 is a flowchart showing an example of a procedure including operations related to the autonomous driving mode of the autonomous driving robot according to this embodiment. [Figure 10] Figure 10 is a flowchart showing an example of a procedure including the operation of the line-following mode by the autonomous mobile robot according to this embodiment. [Figure 11] Figure 11 is a flowchart showing an example of a procedure including the operation related to the positioning mode by the autonomous mobile robot according to this embodiment. [Modes for carrying out the invention]

[0006] The autonomous mobile robot according to this embodiment will be described below with reference to the drawings. In the following description, components having substantially the same function and configuration will be denoted by the same reference numerals, and redundant explanations will be given only when necessary.

[0007] Figure 1 is an overhead view of a factory where the autonomous mobile robot 2 according to this embodiment is operating. The autonomous mobile robot 2 according to this embodiment is intended for use in factories and the like. There are many positions and locations in factories and the like where the autonomous mobile robot 2 is used that require high positioning accuracy. For example, these include the charging position at a charging station for the autonomous mobile robot installed on the floor, the stopping position when the autonomous mobile robot 2 performs a predetermined task, the vicinity of obstacles that hinder the movement of the autonomous mobile robot 2, places where autonomous mobile robots pass each other, places with narrow roads, and places where sharp turns are required. On the other hand, in positions and locations other than those mentioned above, such high positioning accuracy is generally not required.

[0008] One feature of the autonomous mobile robot 2 according to this embodiment is that it has three types of movement modes: autonomous driving mode, line following mode, and positioning mode. In this embodiment, the three types of movement modes are defined as follows: The autonomous driving mode is a mode in which the mobile robot autonomously moves to a target position while avoiding obstacles, based on sensor information such as LiDAR (Light Detection and Ranging, or Laser Imaging Detection and Ranging), by recognizing the surrounding environment based on sensor information such as a camera mounted on the mobile robot, planning a path, and avoiding obstacles. The line following mode is a mode in which the mobile robot detects line-shaped markers 3 laid on the floor surface based on sensor information such as a camera mounted on the mobile robot, and moves along the detected line-shaped markers 3. The line following mode is particularly effective when it is desired to move the mobile robot along a fixed path with a certain degree of positioning accuracy. The positioning mode is a mode in which the mobile robot detects two-dimensional code markers 4 (QR code (registered trademark), AR code, specific pattern, etc.) provided on the floor surface based on sensor information such as a camera mounted on the mobile robot, and accurately positions the mobile robot's position / attitude to a target position / target orientation based on the two-dimensional code markers 4. The positioning mode is particularly effective when high positioning accuracy is required, such as when a mobile robot performs a predetermined task. Line markings 3 are lines or patterns drawn on the floor or other running surface used by the autonomous mobile robot 2 to determine its direction of travel and position when moving autonomously. Line markings 3 may be drawn directly on the floor or provided by attaching linear tape. Of course, line markings 3 include magnetic tape and reflective tape. Two-dimensional code markings 4 are visually readable marks or labels used by the autonomous mobile robot 2 to perform autonomous navigation and motion control. They may directly represent information, such as a QR code, or they may be pictures or specific patterns that are distinguishable from other two-dimensional code markings 4.

[0009] The autonomous mobile robot 2 according to this embodiment can move along a pre-set circular route while switching between three types of movement modes and perform predetermined tasks. By placing a two-dimensional code marker 4 at a location on the circular route where high positional accuracy is required, and placing a line-shaped marker 3 along a predetermined guidance path from the two-dimensional code marker 4, the autonomous mobile robot 2 can be reliably guided to the two-dimensional code marker 4, and its position and orientation can be accurately positioned to a target position and orientation based on the two-dimensional code marker 4. Furthermore, if there is a place on the circular route where the autonomous mobile robot 2 would pass another autonomous mobile robot 2, a line-shaped marker 3 can be placed at that location, allowing the autonomous mobile robot 2 to move along the line-shaped marker 3 and reduce the risk of collision with another autonomous mobile robot 2. In addition, if there is a place on the circular route where the path is narrow and requires a sharp turn, a line-shaped marker 3 can be placed at that location, and a two-dimensional code marker 4 can be placed along the line-shaped marker 3, allowing the autonomous mobile robot 2 to move along the line-shaped marker 3 and correct its position and orientation to a target position and orientation based on the two-dimensional code marker 4 along the way. As a result, the autonomous robot 2 can move without colliding with other autonomous robots 2 or obstacles, even in places where positional accuracy cannot be guaranteed in the autonomous driving mode described above and where movement is difficult. Note that providing a two-dimensional code marker 4 along a line-shaped marker 3 may include both providing a two-dimensional code marker 4 on the line-shaped marker 3 and providing a two-dimensional code marker 4 next to the line-shaped marker 3.

[0010] For example, as shown in Figure 1, three two-dimensional code markers 4b, 4c, and 4e are provided at the unloading position P3 where workpiece A is unloaded by the robot arm 5a, at the unloading position P4 where workpiece B is unloaded by the robot arm 5b, and at the loading position P6 where workpieces A and B are loaded into the robot arm 5d. Line-shaped markers 3a are provided along a guidance path that continuously connects positions P3, P4, and P6 in straight and curved lines in order to guide the autonomous mobile robot 2 to the two-dimensional code markers 4b, 4c, and 4e. Furthermore, at position P2 on the line-shaped markers 3a (guidance path) before the unloading position P3, a two-dimensional code marker 4a is provided to correct the position and orientation of the autonomous mobile robot 2 as it moves toward the unloading position P3, where high positioning accuracy is required first on the circular route. At position P5 between the unloading position P3 and the loading position P6, a two-dimensional code marker 4d is provided to correct the position and orientation of the autonomous mobile robot 2 to prevent collisions with pillars 5c or robot arms 5d in the factory. Furthermore, a two-dimensional code marker 4f is provided at the charging position P8 in the charging station, and a line-shaped marker 3b is provided along the guidance path that guides the autonomous mobile robot 2 to the charging position P8.

[0011] Thus, according to the autonomous mobile robot 2 of this embodiment, by providing two-dimensional code markers 4 at locations on the circular route where high positional accuracy is required, the required positional accuracy for the autonomous mobile robot 2 can be ensured. Furthermore, by providing line-shaped markers 3 extending from the two-dimensional code markers 4, the autonomous mobile robot 2 can be reliably guided to the two-dimensional code markers 4. On the other hand, since it is not necessary to provide two-dimensional code markers 4 and line-shaped markers 3 in other areas of the circular route where high positional accuracy is not required, the unnecessary increase in two-dimensional code markers 4 and line-shaped markers 3 lines can be suppressed compared to the case where two-dimensional code markers 4 and line-shaped markers 3 lines are provided over the entire length of the circular route, and maintenance such as replacement of these markers can be made easier.

[0012] Figure 2 shows a side view of the autonomous mobile robot 2. As shown in Figure 2, the autonomous mobile robot 2 is connected to a server device 6 via a network 9 and works in cooperation with the server device 6 to build a client-server system. The autonomous mobile robot 2 has a robot body 21. A pair of steering wheels 22a are provided on the front side of the robot body 21, and a pair of drive wheels 22b are provided on the rear side. A camera 27 (forward camera 27) for photographing line-shaped markers 3 having a color distinguishable against the color of the floor surface is mounted on the front of the robot body 21 via a jig, facing diagonally downwards. The mounting position of the forward camera 27 is not limited to the above, as long as it can photograph the floor surface in front of the robot body 21. A camera 28 (downward camera 28) for photographing two-dimensional code markers 4 is mounted on the bottom of the robot body 21 via a jig, facing downwards. The mounting position of the downward camera 28 is not limited to the above, as long as it can photograph the floor surface below the robot body 21. LiDAR 29 (29a, 29b, 29c, 29d) is mounted on each of the front, back, left, and right sides of the robot body 21 as a distance sensor. The mounting positions of the LiDAR 29 are not limited to those mentioned above, as long as they can sense the distance to obstacles in front of, behind, to the left, and to the right of the robot body 21. In this embodiment, the front camera 27 and the downward camera 28 are separate, but the front camera 27 may also serve as the downward camera 28 as long as it can recognize the line-shaped markings 3 and two-dimensional code markings 4 provided on the floor.

[0013] The robot body 21 houses a control device 20 that functions as the central control unit of the autonomous mobile robot 2. The robot body 21 also houses a steering mechanism (not shown) for changing the direction of a pair of steering wheels 22a, a first motor 23 that generates power to drive the steering mechanism, a first motor driver 24 that controls the first motor 23, a second motor 25 that generates power to drive the drive mechanism, a second motor driver 26 that controls the second motor 25, a rechargeable battery 30, and a charge sensor 31 that detects the remaining charge of the rechargeable battery 30 or a value for deriving the remaining charge. The charge sensor 31 detects the remaining charge or a current value and voltage value corresponding to the remaining charge, and is actually implemented as a detection unit for detecting discharge current (discharge voltage) on a power management board for controlling the input and output of the rechargeable battery 30. Of course, it could also be a voltage sensor that detects the voltage between the terminals of the rechargeable battery, or a current sensor that detects the current flowing through the rechargeable battery. The control device 20 collects and analyzes information from various sensors equipped on the autonomous mobile robot 2 in real time and controls the drive of the first and second motors 23 and 25.

[0014] Figure 3 shows the hardware configuration of the control device 20 mounted on the autonomous mobile robot 2. As shown in Figure 3, the control device 20 has a processor 41. RAM 42, ROM 43, storage device 44, communication device 45, driver interface 46, camera interface 47, and sensor interface 48 are connected to the processor 41 via a system bus 40. In addition, the control device 20 (processor 41) is connected to a first motor driver 24 and a second motor driver 26 via the driver interface 46, to a forward camera 27 and a downward camera 28 via the camera interface 47, and to multiple LiDARs 29 and a charging sensor 31 that detects the remaining charge of the rechargeable battery 30 or corresponding data via the sensor interface 48.

[0015] The processor 41 is composed of, for example, a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). RAM 42 functions as the main memory, work area, etc., of the processor 41. ROM 43 stores the BIOS (Basic Input Output System) and operating system program (OS) executed by the processor 41.

[0016] The communication device 45 sends and receives data to and from the server device 6 in accordance with the control of the processor 41. The server device 6 stores a sign information management table that summarizes sign information related to the two-dimensional code sign 4, a task sequence that defines a series of tasks to be performed by the autonomous mobile robot 2, and a charging information management table that manages the remaining charge of each autonomous mobile robot 2.

[0017] The first motor driver 24 supplies drive power to the first motor 23 according to a control signal from the processor 41. The first motor 23 drives the steering mechanism, thereby changing the orientation of the pair of steering wheels 22a and changing the direction of movement of the robot body 21. The second motor driver 26 supplies drive power to the second motor 25 according to a control signal from the processor 41. The second motor 25 drives the drive mechanism, thereby rotating the pair of drive wheels 22b and moving the robot body 21. The pair of steering wheels 22a, the steering mechanism, the first motor 23, the pair of drive wheels 22b, the drive mechanism, and the second motor 25 constitute a movement mechanism for moving the robot body 21. The movement mechanism is controlled by the control device 20, allowing the robot body 21 to move in any direction.

[0018] The front camera 27 operates according to the control of the processor 41. The image data captured by the front camera 27 is input to the control device 20 and mainly used for processing related to the line following mode. The lower camera 28 operates according to the control of the processor 41. The image data captured by the lower camera 28 is input to the control device 20 and mainly used for processing related to the positioning mode. Each of the plurality of LiDARs 29 operates according to the control from the processor 41. The distance data measured by the LiDAR 29 is input to the control device 20 and used for processing related to the autonomous driving mode. The charging sensor 31 operates according to the control from the processor 41. The data representing the remaining battery level of the rechargeable battery detected by the charging sensor 31 is input to the control device 20 and transmitted to the server device 6 by the communication device 45.

[0019] The various data stored in the storage device 44 may be recorded on a removable medium (non-temporary storage medium) such as a USB and distributed to the user, or may be distributed by being downloaded to the control device 20 via a network.

[0020] FIG. 4 is a diagram showing an example of a label information management table stored in the storage device 44. The label information management table manages various label information regarding the two-dimensional code label 4. The label information includes a label ID, a label size, a target position, a target orientation, indicator control, and a traveling speed. The label ID is an example of identification information for identifying the two-dimensional code label 4. The label size is used to correct a preset correspondence relationship between an image coordinate system defined on a captured image captured by the lower camera 28 and a robot coordinate system based on the autonomous mobile robot 2. The target position and the target orientation respectively indicate the destination of the autonomous mobile robot 2 with respect to the two-dimensional code label 4 and the orientation of the autonomous mobile robot 2 at the destination. For example, the target position is represented in an image coordinate system with a specific point on the two-dimensional code label 4 included in the captured image captured by the front camera 27 as the origin. The target orientation is represented as an inclination angle with respect to a specific reference line based on the two-dimensional code label 4 included in the captured image captured by the front camera 27. That is, both the target position and the target orientation are represented in the image coordinate system. The correspondence relationship between the image coordinate system in the images captured by the front camera 27 and the lower camera and the robot coordinate system based on the autonomous mobile robot 2 is specified in advance, and the position and orientation on the image coordinate system on the captured image can be converted into the robot coordinate system. The indicator control is for setting a notification method for notifying an operator that the positioning mode is in operation. As the notification method, various methods using means such as sound, light, display, etc. can be adopted. The autonomous mobile robot has hardware corresponding to the notification means. The traveling speed indicates the speed of the autonomous mobile robot 2 in the positioning mode.

[0021] Figure 5 shows an example of a task sequence stored in the memory device 44. A task sequence defines a series of tasks to be performed by the autonomous mobile robot 2, along with their order. The task sequence represented by the solid arrows in Figure 5 corresponds to the series of tasks performed by the autonomous mobile robot 2 shown in Figure 1. Here, the task sequence defines six tasks, from the first task to the sixth task, along with their order. As shown in Figure 5, each task defines the destination, the mode of movement to be used to reach the destination, the content of a specific action at the destination, and the mode of movement to be used after the specific action. A specific action is also called a subtask and includes not only physical actions such as movement, unloading, loading, and charging, but also software actions such as switching modes of movement. There may also be multiple specific actions. The dotted arrows indicate that, compared to the basic task sequence represented by the solid lines, two tasks related to charging (the seventh and eighth tasks) have been added after the sixth task.

[0022] Figure 6 shows an example of a charging information management table stored in the storage device 44. The charging information management table manages the charging information of the autonomous mobile robot 2. The charging information includes the robot ID that identifies the autonomous mobile robot 2, the remaining charge, the charging status, and the charging location. The charging status indicates whether or not the autonomous mobile robot 2 is charging. The charging location indicates the charging station being used by the autonomous mobile robot 2. The server device 6 monitors the remaining charge of each autonomous mobile robot 2 and sends a charging instruction along with a task sequence in which a task related to charging has been added to the autonomous mobile robot 2 whose remaining charge falls below a threshold. In this task sequence, it is desirable that the charging station to be used is dynamically set according to the usage status of each charging station of the other autonomous mobile robots 2. This allows for efficient guidance of the autonomous mobile robot 2 to the charging station and suppresses a decrease in the efficiency of task execution by the autonomous mobile robot 2.

[0023] The functional configuration of the control device 20 (autonomous mobile robot 2) will be described below with reference to Figure 7. As shown in Figure 7, the processor 41 functions as the overall control unit 311, transmission unit 312, reception unit 313, battery level information reception unit 314, movement mode setting unit 315, distance data reception unit 321, current position / current posture estimation unit 323, path creation unit 325, first image data reception unit 331, line-shaped marker detection unit 333, first target position / target posture setting unit 335, second image data reception unit 341, two-dimensional code marker detection unit 343, marker ID identification unit 345, second target position / target posture setting unit 347, and motion control unit 350 by executing the control program stored in the memory device 44.

[0024] The central control unit 311 comprehensively controls each part that performs processing related to the operation of the autonomous mobile robot 2. The transmitting unit 312 transmits various information to the server device 6. The various information that the transmitting unit 312 transmits to the server device 6 includes information on the remaining charge and requests to acquire task sequences. The receiving unit 313 receives various information from the server device 6. The various information that the receiving unit 313 receives from the server device 6 includes task sequences, indicator information, and charging instructions. The movement mode setting unit 315 sets one of the following modes: autonomous driving mode, line following mode, and positioning mode.

[0025] The functions related to autonomous driving mode are mainly realized by the functions of the distance data receiving unit 321, the current position / current posture estimation unit 323, the path creation unit 325, and the motion control unit 350. The distance data receiving unit 321 receives distance data in real time from each of the multiple LiDARs 29. Distance data is data about obstacles around the autonomous driving robot 2 and the distance to objects. The current position / current posture estimation unit 323 estimates the current position / current posture of the autonomous driving robot 2 on the map using the distance data received by the distance data receiving unit 321 by referring to the factory map data. The path creation unit 325 creates a movement path from the current position / current posture of the autonomous driving robot 2 on the map estimated by the current position / current posture estimation unit 323 to the target position / target posture of the autonomous driving robot 2 on the map which is set in advance. The motion control unit 350 controls the movement mechanism (first motor 23 and second motor 25) to move the autonomous mobile robot 2 along the path created by the path creation unit 325.

[0026] The functions related to the line-following mode are mainly realized by the functions of the first image data receiving unit 331, the line-shaped marker detection unit 333, the first target position / target attitude setting unit 335, and the motion control unit 350. The first image data receiving unit 331 repeatedly receives image data captured by the front camera 27 in real time from the front camera 27. The image coordinate system defined on the captured image captured by the front camera 27 is associated with the robot coordinate system based on the autonomous mobile robot 2. The line-shaped marker detection unit 333 detects the line-shaped marker 3 by performing predetermined image processing on the image data captured by the front camera 27. Specifically, the line-shaped marker detection unit 333 distinguishes between light and dark by binarizing the captured image, performs threshold processing on the binarized captured image to highlight the features of the line-shaped marker 3, then performs contour extraction to extract the contour of the shape, and finally uses pattern matching to confirm whether the extracted contour matches the pattern of the line-shaped marker 3. Of course, if it is possible to detect the line-shaped marker 3 from the captured image, the method is not limited to the above. The first target position / target attitude setting unit 335 calculates the position and orientation of the line-shaped marker 3 detected by the line-shaped marker detection unit 333 on the captured image, and converts the calculated position and orientation on the captured image into a robot coordinate system based on the autonomous mobile robot 2, thereby setting the target position / target attitude of the autonomous mobile robot 2 to follow along the line-shaped marker 3. The motion control unit 350 controls the movement mechanism (first motor 23 and second motor 25) to move to the target position / target attitude set by the first target position / target attitude setting unit 335.

[0027] The functions related to the positioning mode are mainly realized by the functions of the second image data receiving unit 341, the two-dimensional code mark detection unit 343, the mark ID identification unit 345, the second target position / target attitude setting unit 347, and the motion control unit 350. The second image data receiving unit 341 repeatedly receives image data captured by the lower camera 28 in real time from the lower camera 28. The image coordinate system set on the captured image captured by the lower camera 28 is associated with the robot coordinate system based on the autonomous mobile robot 2. The two-dimensional code mark detection unit 343 detects the two-dimensional code mark 4 by performing predetermined image processing on the image data captured by the lower camera 28. At least one of the following processes is used to detect the two-dimensional code mark 4: pattern matching processing, threshold processing, and contour extraction processing. The mark ID identification unit 345 reads a bit pattern from the image portion corresponding to the two-dimensional code mark 4 detected by the two-dimensional code mark detection unit 343, and identifies the mark ID represented by the two-dimensional code mark 4 from the read bit pattern. The second target position / attitude setting unit 347 refers to the sign information management table to identify the target position / attitude based on the two-dimensional code sign 4 corresponding to the sign ID, and converts the identified target position / attitude on the captured image into a robot coordinate system based on the autonomous mobile robot 2. As a result, the second target position / attitude setting unit 347 sets the target position and target attitude of the autonomous mobile robot 2 to move to the target position / attitude based on the two-dimensional code sign 4. The motion control unit 350 controls the movement mechanism (first motor 23 and second motor 25) to move the autonomous mobile robot 2 to the target position / attitude set by the second target position / attitude setting unit 347. Furthermore, the motion control unit 350 controls the autonomous mobile robot 2 according to the operations defined after positioning.

[0028] The following outline of the operation process of the autonomous mobile robot 2 will be explained with reference to Figure 8. As shown in Figure 8, when the autonomous mobile robot 2 is started by an operator or the like, the transmission unit 312 sends a request to the server device 6 to acquire a task sequence (S11), and the reception unit 313 receives the task sequence and indicator information related to the two-dimensional code indicator 4 included in the task sequence as a response from the server device 6 to the request to acquire a task sequence (S12). The overall control unit 311 registers the task sequence received by the reception unit 313 together with the indicator information in the storage device 44 (S13). Then, the overall control unit 311 controls each part, and the autonomous mobile robot 2 executes a series of operations according to the task sequence (S14). The series of operations by the autonomous mobile robot 2 according to the task sequence are repeatedly executed until a predetermined termination condition is met (S15; No), and are terminated when the predetermined termination condition is met (S15; Yes). Once the actions according to the task sequence are completed, the autonomous mobile robot 2 moves to the standby position according to the control of the motion control unit 350 (S16). Then, the overall control unit 311 cancels the registration of the task sequence (S17). The termination conditions include the current time reaching a predetermined time, or the user inputting a termination command.

[0029] The following describes the operation procedure related to the autonomous driving mode of the autonomous driving robot 2 with reference to Figure 9. In Figure 9, the processes related to steps S21 to S25 correspond to the operation processes related to the autonomous driving mode. Of course, the entire process related to steps S21 to S30, including the series of processes related to switching the movement mode related to steps S26 to S30, may also be considered the process related to the autonomous driving mode. The series of processes related to switching the movement mode related to steps S26 to S30 may be processes independent of the processes related to each movement mode. As shown in Figure 9, when the autonomous driving mode is started, the distance data receiving unit 321 receives distance data from the LiDAR 29 (S21), and the current position / current posture estimation unit 323 estimates the current position / current posture of the autonomous driving robot 2 using the distance data received by the distance data receiving unit 321 (S22). The path creation unit 325 creates a path from the current position / current orientation of the autonomous mobile robot 2 estimated in step S22 to a preset target position / target orientation of the autonomous mobile robot 2 (S23), and the motion control unit 350 controls the movement mechanism to move along the path created in step S23 (S24). The processes related to steps S21 to S24 are repeatedly executed until the autonomous mobile robot 2 moves to the target position / target orientation (S25; No). When the autonomous mobile robot 2 moves to the target position / target orientation (S25; Yes), the first image data receiving unit 331 receives image data from the front camera 27 (S26). The line-shaped marker detection unit 333 performs image processing on the image received by the first image data receiving unit 331 to detect the line-shaped marker 3 (S27). When an image portion representing the line-shaped marker 3 is detected from the image captured by the front camera 27 (S28; Yes), the movement mode setting unit 315 switches the movement mode from autonomous driving mode to line-following mode (S29). On the other hand, when an image portion representing the line-shaped marker 3 is not detected from the image captured by the front camera 27 (S28; No), the control unit 311 performs a predetermined error processing (S30), and the movement of the autonomous driving robot 2 in autonomous driving mode is terminated.Error handling only needs to notify the worker that a malfunction or other problem has occurred. Examples include forcibly returning the autonomous robot 2 to its standby position, illuminating a warning light, or emitting a warning sound. According to the above process, when the autonomous robot 2 moves to the target position / target orientation in autonomous driving mode, or after moving to the target position / target orientation in autonomous driving mode, when a line-shaped marker 3 is detected from the image captured by the forward camera 27, the movement mode switches from autonomous driving mode to line-following mode.

[0030] The following describes the operation procedure for the line-following mode by the autonomous mobile robot 2 with reference to Figure 10. In Figure 10, the movement mode switching process in step S52 may be a process independent of the processes related to each movement mode. As shown in Figure 10, when the line-following mode is started, the first image data receiving unit 331 receives captured image data from the front camera 27 (S41). The line-shaped marker detection unit 333 performs image processing on the captured image received by the first image data receiving unit 331 to detect the line-shaped marker 3 (S42). The first target position / target attitude setting unit 335 sets a target position / target attitude for the autonomous mobile robot 2 to follow the line-shaped marker 3 based on the position / orientation of the line-shaped marker 3 detected by the line-shaped marker detection unit 333 (S43). The motion control unit 350 controls the movement mechanism so that the autonomous mobile robot 2 moves to the target position / target attitude set in step S43 (S44). The second image data receiving unit 341 receives captured image data from the lower camera 28 (S45). The two-dimensional code mark detection unit 343 performs image processing on the captured image received by the second image data receiving unit 341 to detect the two-dimensional code mark 4 (S46). The processes related to steps S41 to S46 are repeatedly executed from the start of the line-following mode until the autonomous mobile robot 2 moves a predetermined distance, until the two-dimensional code mark 4 is detected from the image captured by the lower camera 28 (S47; No, S48; No). If the two-dimensional code mark 4 is not detected from the image captured by the lower camera 28 during the time from the start of the line-following mode until the autonomous mobile robot 2 moves a predetermined distance (S47; No, S48; Yes), the control unit 311 performs error processing (S49), and control of the autonomous mobile robot 2 in line-following mode is terminated. On the other hand, if a two-dimensional code mark 4 is detected from the image captured by the downward camera 28 between the start of the line-following mode and the autonomous robot 2 has moved a predetermined distance (S47; Yes), the mark ID identification unit 345 identifies the mark ID corresponding to the two-dimensional code mark 4 based on the image portion representing the two-dimensional code mark 4 (S50).The processes related to steps S41 to S50 are repeatedly executed until the indicator ID specified in the task sequence is identified in step S50 (S51; No). On the other hand, when the indicator ID specified in the currently executing task sequence is identified in step S50 (S51; Yes), the movement mode setting unit 315 switches the movement mode from line-following mode to positioning mode (S50), and the control of the autonomous mobile robot 2 in accordance with the line-following mode is terminated. According to the above process, when the autonomous mobile robot 2 detects a two-dimensional code indicator 4 from the image captured by the lower camera 28, or when a two-dimensional code indicator 4 is detected from the image captured by the lower camera 28 and the detected two-dimensional code indicator 4 is the two-dimensional code indicator to be positioned, that is, when it is the two-dimensional code indicator specified in the task sequence, the movement mode is switched from line-following mode to positioning mode.

[0031] The following describes the operation procedure related to the positioning mode by the autonomous mobile robot 2 with reference to Figure 11. In Figure 11, the entire process related to steps S61 to S73, including the processing related to specific operations in steps S69 to S70 and the switching process to the next movement mode in steps S71 to S73, may be considered as the process related to the positioning mode, or the processing related to specific operations in steps S69 to S70 and the series of processes related to switching movement modes in steps S71 to S73 may be processes independent of the processes related to each movement mode. As shown in Figure 11, when the positioning mode is started, the second image data receiving unit 341 receives captured image data from the lower camera 28 (S61). The two-dimensional code mark detection unit 343 performs image processing on the captured image received by the second image data receiving unit 341 to detect the two-dimensional code mark 4 (S62). If the two-dimensional code mark 4 cannot be detected from the captured image (S63; No), the control unit 311 proceeds to step S68, which will be described later. When a two-dimensional code mark 4 is detected from the captured image (S63; Yes), the second target position / target posture setting unit 347 sets the target position / target posture based on the two-dimensional code mark 4 detected by the two-dimensional code mark detection unit 343 (S64). The motion control unit 350 controls the movement mechanism to move the autonomous mobile robot 2 to the target position / target posture set by the second target position / target posture setting unit 347 (S65). The series of processes related to movement in steps S61 to S65 are executed until a predetermined time has elapsed from the start of the movement process related to step S65 (S66; No, S67; No). On the other hand, if the autonomous mobile robot 2 cannot be moved to the target position / target posture even after a predetermined time has elapsed from the start of the movement process related to step S65 (S66; No, S67; Yes), the overall control unit 311 performs error processing (S68), and the movement of the autonomous mobile robot 2 according to the positioning mode is terminated. When the autonomous mobile robot 2 has moved to the target position / target orientation (S66; Yes), and if a post-movement action has been set (S69; Yes), the autonomous mobile robot 2 will execute the set action according to the control of the motion control unit 350 (S70), and the movement mode will be switched from positioning mode to another movement mode.On the other hand, if no action is set after movement (S69; No), the movement mode can be switched from positioning mode to another movement mode without performing any specific action, that is, simply by correcting the position / orientation of the autonomous mobile robot 2. If the next movement mode specified in the task sequence is autonomous mobile mode (S71; autonomous mobile mode), the movement mode setting unit 315 switches the movement mode from positioning mode to autonomous mobile mode (S72). If the next movement mode specified in the task sequence is line following mode (S71; line following mode), the movement mode setting unit 315 switches the movement mode from positioning mode to line following mode (S73). According to the above process, when the autonomous mobile robot 2 moves to the target position / target orientation based on the two-dimensional code sign 4, or when a specific action is performed after movement, the movement mode switches from positioning mode to line following mode or autonomous mobile mode.

[0032] The autonomous driving robot 2 according to this embodiment, as described above, also provides the following effects. For example, if an autonomous mobile robot 2 does not have a line-following mode and attempts to move to the vicinity of a specific position in autonomous driving mode, and then move precisely to that specific position in positioning mode, the following problems may occur. Specifically, it is desirable that the downward camera 28, which photographs the floor surface to detect the two-dimensional code mark 4, be installed at the bottom of the robot body 21 so as not to be affected by light and so as to be able to photograph from a direction perpendicular to the floor surface. On the other hand, autonomous mobile robots 2 used for workpiece transport and the like are designed so that the distance between the robot body 21 and the floor surface is as narrow as possible in order to lower the center of gravity. As a result, the downward camera 28 is placed in a position close to the floor surface, so that the two-dimensional code mark 4, which is installed at a specific position or a position corresponding to a specific position, has to be small enough to fit within the field of view of the downward camera 28, and to remain within the field of view of the downward camera 28 even if the autonomous mobile robot 2 is slightly misaligned relative to the two-dimensional code mark 4. However, because the two-dimensional code marker 4 is small, even when moving to a specific location in autonomous driving mode, the small two-dimensional code marker 4 could not be captured within the field of view of the downward camera 28, sometimes causing the series of tasks to be interrupted.

[0033] The inventors have discovered that the above-mentioned problems can be suitably resolved by inserting a line-following mode between the autonomous driving mode and the positioning mode. That is, the autonomous driving robot 2 according to this embodiment has three types of movement modes: autonomous driving mode, line-following mode, and positioning mode, and can perform a series of tasks by switching between the three types of movement modes along a pre-set circular route. The autonomous driving robot 2 can move to a target position near the end of the line-shaped marker 3 in autonomous driving mode, then move along the line-shaped marker 3 in line-following mode to a two-dimensional code marker 4 provided at a specific position or a position corresponding to the specific position, and finally move precisely to a specific position corresponding to the two-dimensional code marker 4 in positioning mode. The positioning accuracy required of the autonomous mobile robot 2 to bring the line-shaped marker 3 into the field of view of the forward camera 27 can be lower than the positioning accuracy required of the autonomous mobile robot 2 to bring the two-dimensional code marker 4 into the field of view of the downward camera 28. Therefore, by interposing a line-following mode between the autonomous driving mode and the positioning mode, it is possible to reduce the occurrence of situations where a series of tasks are interrupted because the line-shaped marker 3 does not fit into the field of view of the forward camera 27 when switching from the autonomous driving mode to the line-following mode. Once the line-shaped marker 3 is detected, the autonomous mobile robot 2 can reliably move along the line-shaped marker 3 to a position where the two-dimensional code marker 4 fits into the field of view of the downward camera 28, and can move to a target position / target orientation based on the two-dimensional code marker 4 in positioning mode.

[0034] Because the autonomous mobile robot 2 has three movement modes, on the circular route traveled by the autonomous mobile robot 2, by simply placing two-dimensional code markers 4 at positions requiring high positioning accuracy or in the vicinity thereof, and placing line-shaped markers 3 extending from the two-dimensional code markers 4, the autonomous mobile robot 2 can be reliably guided to the two-dimensional code markers 4. On the other hand, since it is not necessary to place two-dimensional code markers 4 and line-shaped markers 3 in other areas of the circular route where high positioning accuracy is not required, the unnecessary increase in the number of two-dimensional code markers 4 and line-shaped markers 3 lines can be suppressed compared to when two-dimensional code markers 4 and line-shaped markers 3 lines are placed along the entire length of the circular route, and maintenance such as replacement of these markers can be made easier.

[0035] In this embodiment, the autonomous mobile robot 2 constituted a client-server system together with the server device 6. However, the autonomous mobile robot 2 according to this embodiment may be configured as a standalone unit. When the autonomous mobile robot 2 according to this embodiment is configured as a standalone unit, it is sufficient that the task sequence and signage information that were stored in the server device 6 in this embodiment are pre-stored in the autonomous mobile robot 2. Of course, by configuring it as a client-server system, the server device 6 can dynamically change the destination of the autonomous mobile robot 2. For example, even if the line-shaped signage 3 branches off in the middle, if a two-dimensional code signage 4 is provided at the branching point, the autonomous mobile robot 2 can, upon reading the two-dimensional code signage 4 at the branching point, query the server device 6 about which branch to move to, and move towards the branch according to the command received from the server device 6. Similarly, if multiple charging stations are installed, the autonomous mobile robot 2 can move to the charging station instructed by the server device 6. By configuring the system in this client-server manner, the server device 6 can instruct each of the multiple autonomous mobile robots 2 to change their destination, pause, etc., according to the movement position of each autonomous mobile robot 2 and the execution status of each autonomous mobile robot 2's task, thereby improving the overall task execution efficiency. Furthermore, by simply changing the task sequence, the circling route of the autonomous mobile robots 2 can be changed, or a part of a series of tasks can be modified, and by simply changing the sign information, the target position / target orientation can be changed. This enables flexible response to changes in the surrounding environment, such as changes in the position of the robot arm 5 or the placement of new obstacles.

[0036] In this embodiment, the autonomous mobile robot 2 received a task sequence from the server device 6 after startup and managed the next task to be executed by the autonomous mobile robot 2. However, the autonomous mobile robot 2 may query the server device 6 for information on the next task to be executed each time a task is completed, and execute the next task according to the task information received from the server device 6.

[0037] In this embodiment, two-dimensional code markers 4 were provided at locations where high positioning accuracy was required or where position / orientation needed to be corrected. However, the two-dimensional code markers 4 may also be provided at branching points of the line-shaped markers 3. The autonomous mobile robot 2 transmits the marker ID corresponding to the two-dimensional code marker 4 provided at the branching point of the line-shaped markers 3 to the server device 6. The server device 6 then determines the branching destination, taking into account the congestion status of other autonomous mobile robots 2 at the branching point, and transmits this to the autonomous mobile robot 2. This allows the autonomous mobile robot 2 to move to a location appropriate to the situation at the branching point of the line-shaped markers 3, thereby improving the overall task execution efficiency.

[0038] The autonomous mobile robot 2 according to this embodiment employs a so-called Ackermann steering mechanism, but the mobility mechanism is not limited to this embodiment as long as it can move freely in all directions. Therefore, the autonomous mobile robot 2 may have a mechanism corresponding to various mobility methods, such as an omni-wheel system using omni-wheels that can move freely in all directions, a differential drive system consisting of two drive wheels and one or more casters that performs turning and movement by the difference in rotational speed of each drive wheel, or a crawler system that uses tracks instead of wheels.

[0039] The autonomous mobile robot 2 according to this embodiment has a forward-facing camera 27 capable of photographing the floor surface in front of it, and line-shaped markers 3 having a color distinguishable from the color of the floor surface are laid on the floor surface. However, the configuration is not limited to this embodiment as long as the autonomous mobile robot 2 can be moved along the line-shaped markers 3 laid on the floor surface. For example, magnetic tape may be used as the line-shaped markers 3, and the autonomous mobile robot 2 may have a magnetic sensor or a Hall effect sensor instead of a forward-facing camera 27.

[0040] Regarding the switching of movement modes, this embodiment does not describe an example of switching from line-following mode to autonomous driving mode, but of course, the movement mode setting unit 315 may switch from line-following mode to autonomous driving mode. For example, the movement mode setting unit 315 switches the movement mode from line-following mode to autonomous driving mode when it detects the end of the line-shaped marker 3, a mark provided on the line-shaped marker 3, etc., from the image captured by the front camera 27.

[0041] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0042] 2...Autonomous mobile robot, 3...Line-shaped marker, 4...2D code marker, 5...Obstacles (robot arm, factory pillars).

Claims

1. The robot body and A distance sensor provided on the robot body, A front camera for photographing the front of the robot body, A downward camera for photographing the area below the robot body, A moving mechanism for moving the robot body, A setting unit for setting the movement mode of the robot body, The system comprises a control unit that controls the movement mechanism in the set movement mode, The setting unit sets one of the following modes as the movement mode: an autonomous driving mode in which the vehicle autonomously travels along a predetermined route based on the output of the distance sensor; a line following mode in which the vehicle moves along a line-shaped marker laid on the floor surface based on the output of the front camera; and a positioning mode in which the vehicle adjusts its position and attitude to a target position and attitude based on a two-dimensional code marker laid on the floor surface along the line-shaped marker based on the output of the lower camera. Autonomous mobile robot.

2. The autonomous robot according to claim 1, wherein the setting unit switches the movement mode from the autonomous driving mode to the line following mode when the robot moves to a target position and target orientation in the autonomous driving mode.

3. The autonomous robot according to claim 1, wherein the setting unit, after moving to a target position and target orientation in the autonomous driving mode, switches the movement mode from the autonomous driving mode to the line following mode when the line-shaped marker is detected from an image captured by the forward camera.

4. The autonomous mobile robot according to claim 1, wherein the setting unit switches the movement mode from the line-following mode to the positioning mode when the robot is moving along the line-shaped marker in the line-following mode and the two-dimensional code marker is detected from an image captured by the downward camera.

5. The autonomous mobile robot according to claim 1, wherein the setting unit, while moving along the line-shaped marker in line-following mode, detects the two-dimensional code marker from an image captured by the downward camera, and when the detected two-dimensional code marker is a two-dimensional code marker to be positioned, switches the movement mode from the line-following mode to the positioning mode.

6. The autonomous driving robot according to claim 1, wherein the setting unit maintains the movement mode in line-following mode while the line-shaped marker is continuously being photographed by the forward-facing camera, and switches the movement mode from line-following mode to autonomous driving mode when the end portion of the line-shaped marker is detected from the image captured by the forward-facing camera.

7. In the positioning mode, the autonomous mobile robot's current position and current orientation are aligned with the target position and target orientation, respectively, with respect to the two-dimensional code mark, and then a specific operation associated with the two-dimensional code mark is performed by the autonomous mobile robot according to claim 1.

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