JP7164085B2 - Work transport method using moving body, computer program, and moving body - Google Patents

Description

The present disclosure relates to a work transfer method using a mobile body, a computer program, and a mobile body.

Research and development of autonomous mobile objects such as automated guided vehicles and mobile robots are underway. For example, Japanese Patent Application Laid-Open Nos. 2008-129614 and 2012-108756 disclose examples of mobile objects that autonomously move while referring to an environment map.

JP-A-2008-129614 JP 2012-108756 A

For example, in a factory or the like, consider an example in which an automatic guided vehicle receives a work from a conveyor, places the work on a conveyor table, conveys the work, and delivers the work to another conveyor. Depending on the relationship with the process after handing over, the orientation of the work at the time of handing over may be determined in advance. If the direction of the workpiece differs between when it is received and when it is handed over, it is necessary to adopt a carrier table equipped with a turning mechanism for the unmanned carrier. However, providing such a special mechanism increases the cost.

An embodiment of the present disclosure provides a work transfer technique using an automatic guided vehicle that does not require a turning mechanism.

According to an exemplary embodiment of the present disclosure, a work transfer method is a work transfer method using a moving body, the moving body can move autonomously, and A transport table is provided on which the work is placed during transport, and the transport method comprises: (a) causing the moving body to receive the work on the transport table at a first position; (c) moving the moving body to the second position to transfer the workpiece to the rack; (d) after transferring the workpiece, moving the moving body to (e) causing the moving body to receive the workpiece transferred to the rack on the conveying table; (f) moving the moving body to a third position; (g) moving the moving body to the third position; position, wherein the orientation of the work at the third position is different from the orientation of the work at the first position with respect to the traveling direction of the moving body.

According to another exemplary embodiment of the present disclosure, the computer program is a computer program for causing a controller of a moving body to execute the transport method described above.

According to still another exemplary embodiment of the present disclosure, the mobile body is a mobile body that can move autonomously, and includes a drive device that moves the mobile body, and a drive device that controls the drive device. and a carrier table, wherein the controller causes the carrier table to receive a workpiece at a first position, moves the mobile body to a second position where a rack is installed, and At the second position, the work is transferred to the rack, the direction of the moving body is changed after the work is transferred, the work transferred to the rack is received on the transfer table, and the moving body is moved to the second position. By moving the work to position 3 and delivering the work at the third position, the work is transported by the moving body, and the orientation of the work at the third position is the first moving body with respect to the traveling direction of the moving body. Different from the orientation of the workpiece in position.

According to an exemplary embodiment of the present disclosure, a mover receives a workpiece at a first location, transports it to a second location provided with a table, and places the workpiece on the table. The moving body turns, then receives the placed work from the table and conveys it to the third position. At this time, the orientation of the work differs between the first position and the third position with respect to the traveling direction of the moving body. As a result, it is possible to change the direction in which the workpiece is discharged at low cost by a simple operation of the moving body.

FIG. 1 is a block diagram showing a schematic configuration of a moving object in an exemplary embodiment of the present disclosure; FIG. FIG. 2 is a flow chart showing an overview of the operation of the moving body. FIG. 3 is a schematic diagram of a control system that controls travel of each AGV according to the present disclosure. FIG. 4 is a diagram showing an example of a moving space S in which an AGV exists. FIG. 5A is a diagram showing the AGV and towing truck before they are connected. FIG. 5B is a diagram showing a connected AGV and tow truck. FIG. 6 is an external view of an exemplary AGV according to this embodiment. FIG. 7A is a diagram showing a first hardware configuration example of the AGV. FIG. 7B is a diagram showing a second hardware configuration example of the AGV. FIG. 8A is a diagram showing an AGV that generates a map while moving. FIG. 8B is a diagram showing an AGV that generates a map while moving. FIG. 8C is a diagram showing an AGV that generates a map while moving. FIG. 8D is a diagram showing an AGV generating a map while moving. FIG. 8E is a diagram showing an AGV generating a map while moving. FIG. 8F is a diagram schematically showing part of the completed map. FIG. 9 is a diagram showing an example in which a map of one floor is composed of a plurality of partial maps. FIG. 10 is a diagram showing a hardware configuration example of an operation management device. FIG. 11 is a diagram schematically showing an example of an AGV moving route determined by the operation management device. FIG. 12 is a diagram schematically showing the 10 that conveys the work 80. As shown in FIG. FIG. 13A illustrates changes in position and attitude of AGV 10 operating in accordance with an exemplary embodiment over time. FIG. 13B illustrates changes in position and attitude of AGV 10 operating in accordance with an exemplary embodiment over time. FIG. 14A is a diagram showing the AGV 10 heading toward the rack 210 while conveying the workpiece 80. FIG. 14B is a diagram showing the work 80 transferred to the rack 210. FIG. FIG. 14C is a diagram showing AGV 10 receiving workpiece 80 and reoriented. FIG. 15 shows the AGV 10 on which the lifter mechanism 19 is mounted. FIG. 16A is a side view showing the relationship between the AGV 10 that transports the workpiece 80 and the rack 210. FIG. 16B shows the AGV 10 with the lifter mechanism 19 extended at a position away from the rack 210. FIG. 16C is a diagram showing AGV 10 entering opening 212 of rack 210. FIG. FIG. 16D is a diagram showing the AGV 10 with the carrier table 13 lowered. FIG. 16E shows the AGV 10 turned 90 degrees clockwise in place. FIG. 16F is a diagram showing the AGV 10 with the lifter mechanism 19 extended. FIG. 16G shows the AGV 10 turned in place clockwise an additional 90 degrees. 16H shows AGV 10 having escaped from opening 212 of rack 210. FIG.

<Term>
Prior to describing embodiments of the present disclosure, definitions of terms used herein will be provided.

"Automated Guided Vehicle" (AGV) means a trackless vehicle that loads cargo manually or automatically into its main body, travels automatically to a designated location, and unloads manually or automatically. "Automated guided vehicle" includes automated towing vehicles and automated forklifts.

The term "unmanned" means that no person is required to steer the vehicle, and does not exclude that the AGV carries "persons (e.g., those loading and unloading goods)".

An “unmanned tractor” is a trackless vehicle that automatically travels to a designated location by towing a trolley that loads and unloads cargo manually or automatically.

An “unmanned forklift” is a trackless vehicle equipped with a mast that raises and lowers a fork for loading and unloading cargo.

A "trackless vehicle" is a vehicle that has wheels and an electric motor or engine that rotates the wheels.

A “moving body” is a device that moves with a person or load on it, and includes driving devices such as wheels, a bipedal or multipedal walking device, and a propeller that generate a driving force (traction) for movement. The term “mobile” in the present disclosure includes mobile robots, service robots, and drones as well as automated guided vehicles in the narrow sense.

"Automatic driving" includes driving based on commands of a computer operation management system to which the automatic guided vehicle is connected by communication, and autonomous driving by a control device provided in the automatic guided vehicle. Autonomous travel includes not only travel by an automatic guided vehicle toward a destination along a predetermined route, but also travel following a tracking target. Also, the automatic guided vehicle may temporarily travel manually based on instructions from the operator. "Automated driving" generally includes both "guided" driving and "guideless" driving, but in this disclosure means "guideless" driving.

The “guide type” is a system in which derivatives are installed continuously or intermittently, and the guides are used to guide an automatic guided vehicle.

The “guideless type” is a method of guiding without installing a derivative. An automatic guided vehicle according to an embodiment of the present disclosure includes a self-position estimation device and can travel without a guide.

A "self-position estimation device" is a device that estimates a self-position on an environmental map based on sensor data acquired by an external sensor such as a laser range finder.

The "external sensor" is a sensor that senses the state of the exterior of the moving object. External sensors include, for example, laser range finders (also called range sensors), cameras (or image sensors), LIDAR (Light Detection and Ranging), millimeter wave radars, and magnetic sensors.

An "internal sensor" is a sensor that senses the internal state of a moving object. Internal sensors include, for example, rotary encoders (hereinafter sometimes simply referred to as "encoders"), acceleration sensors, and angular acceleration sensors (eg, gyro sensors).

"SLAM" is an abbreviation for Simultaneous Localization and Mapping, which means performing self-localization and environmental map creation at the same time.

<Exemplary embodiment>
An example of a mobile body and a mobile system according to the present disclosure will be described below with reference to the accompanying drawings. Note that more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid unnecessary verbosity in the following description and to facilitate understanding by those skilled in the art. The inventors provide the accompanying drawings and the following description for a full understanding of the present disclosure by those skilled in the art. They are not intended to limit the claimed subject matter.

The moving body described in the present disclosure has a mounting table on which a work, which is an object to be transferred, is placed, and can convey the work while moving autonomously. An example of such a moving body is an automatic guided vehicle (eg, FIG. 6) that transports food as work in a food factory. Hereinafter, an overview of the configuration and operation of the mobile body of the present disclosure will be described with reference to FIGS. 1 and 2. FIG.

FIG. 1 is a block diagram showing a schematic configuration of a moving object in an exemplary embodiment of the present disclosure; FIG. The moving body 101 has a carrier table 103 , a controller 105 and a driving device 107 .

The carrier table 103 is a flat plate on which the work is placed. However, being a flat plate is an example and is not essential.

The controller 105 controls the driving device 107 to move the moving body 101 . Controller 105 may be an integrated circuit (IC) chip such as, for example, a central processing unit (CPU) or digital signal processor. The controller 105 executes computer programs stored in a memory (not shown). Under the control of the controller 105 executing a computer program, the moving body 101 carries out the operation described later to convey the work. The memory may include, for example, semiconductor volatile memory such as RAM, semiconductor non-volatile memory such as flash ROM, and storage device such as hard disk drive. At least part of the memory may be a removable recording medium.

The driving device 107 has a mechanism for moving the moving body 101 . The drive device 109 may comprise, for example, at least one drive electric motor (hereinafter simply referred to as "motor") and a motor control circuit for controlling the motor.

The controller 105 of the moving body 101 according to this embodiment implements the following operations according to a computer program. FIG. 2 is a flow chart showing the operation procedure of the moving body 101. As shown in FIG. The flowchart of FIG. 2 is mainly executed by the controller 105. FIG.

In step S1, the controller 105 detects that a work has been placed on the transport table 103 at a certain position (first position), ie, that the work has been received. Receipt may be detected, for example, by a weight sensor provided on the carrier table 103 or may be detected by pressing a physical switch provided on the carrier table 103 . The first location is, for example, the outlet of the conveyor.

In step S2, the controller 105 controls the driving device 107 to move the moving body 101 to a position (second position) where a rack described later is installed in advance. In step S3, when the moving body reaches the second position, the work is transferred to the rack. For example, the work may be automatically transferred to the rack by the controller 105 causing the moving body to enter the rack. Alternatively, the work may be transferred to the rack by the controller 105 operating a "lifter" to be described later to place the work on the rack.

Next, in step S<b>4 , the controller 105 changes the orientation of the moving body 101 . For example, the controller 105 turns the moving body 101 on the spot by 90 degrees. After that, in step S5, the controller 105 receives the work transferred to the rack on the transport table 103 again, and in step S6, moves the moving body 101 to the work delivery position (third position).

Upon reaching the third position, controller 105 executes step S7. At step S7, the controller 105 transfers the workpiece, for example, to the next conveyor.

Here, attention is focused on the orientation (angle) of the workpiece. The moving body 101 temporarily places the workpiece on the rack during transportation, and rotates by a predetermined angle. As a result, before and after temporary placement of the work, the relative positional relationship between the moving body 101 and the work changes by the turning angle. For example, it is assumed that the controller 105 turns the moving body 101 clockwise K degrees on the spot. After the moving body 101 receives the workpiece again, the workpiece has rotated K degrees counterclockwise as viewed from the moving body 101 . In this embodiment, "K degrees" is an arbitrary angle that does not include rotation of 360 degrees or integral multiples thereof.

Focusing on the orientation of the work with respect to the traveling direction of the moving body, the orientation of the work at the first position when receiving the work differs from the orientation of the work at the third position when delivering the work.

The orientation of the work when the moving body 101 receives the work and the orientation of the work when the moving body 101 delivers the work can be determined independently of each other due to the arrangement of factory equipment such as conveyors. The moving body 101 conveys the work under conditions in which the orientation of the work at the time of reception and at the time of delivery are determined. When it is requested to change the direction of the work between the time of receiving the work and the time of handing over the work, the above-described operation of the moving body 101 can very easily meet the request. Conventionally, a turning mechanism is mounted on the carrier table to change the orientation of the work. orientation change can be realized.

A more specific example in which the mobile body is an automatic guided vehicle will be described below. In this specification, an abbreviation is sometimes used to describe an automatic guided vehicle as an "AGV." It should be noted that the following description can be similarly applied to mobile objects other than AGVs, such as mobile robots, drones, and manned vehicles, unless inconsistent.

A description of operations related to the above operations will be described in more detail in "(7) AGV operation example".

(1) Basic Configuration of System FIG. 3 shows an example of the basic configuration of an exemplary mobile management system 100 according to the present disclosure. The mobile management system 100 includes at least one AGV 10 and an operation management device 50 that manages operation of the AGV 10 . Also shown in FIG. 3 is a terminal device 20 operated by the user 1 .

The AGV 10 is an unmanned guided vehicle capable of "guideless" travel that does not require a dielectric such as a magnetic tape for travel. The AGV 10 can estimate its own position and transmit the estimation result to the terminal device 20 and the operation management device 50 . The AGV 10 can automatically travel within the moving space S according to a command from the operation management device 50 . The AGV 10 can also operate in a "tracking mode" in which it follows a person or other moving object.

The operation management device 50 is a computer system that tracks the position of each AGV 10 and manages the running of each AGV 10 . The traffic management device 50 can be a desktop PC, a notebook PC, and/or a server computer. The operation management device 50 communicates with each AGV 10 via multiple access points 2 . For example, the operation management device 50 transmits to each AGV 10 the coordinate data of the position to which each AGV 10 should go next. Each AGV 10 periodically transmits data indicating its own position and orientation to the operation management device 50, for example, every 100 milliseconds. When the AGV 10 reaches the instructed position, the operation management device 50 further transmits coordinate data of the position to which the vehicle should go next. The AGV 10 can also travel within the moving space S according to the user's 1 operation input to the terminal device 20 . An example of the terminal device 20 is a tablet computer. Typically, the AGV 10 runs using the terminal device 20 when the map is created, and the AGV 10 runs using the operation control device 50 after the map is created.

FIG. 4 shows an example of a moving space S in which three AGVs 10a, 10b and 10c are present. It is assumed that both AGVs are running in the depth direction in the figure. The AGVs 10a and 10b are in the process of transporting loads placed on the top plate. The AGV 10c is running following the AGV 10b in front. For convenience of explanation, reference numerals 10a, 10b, and 10c are attached in FIG. 4, but are described as "AGV 10" below.

The AGV 10 can also transport a load by using a towing truck connected to itself, in addition to the method of transporting the load placed on the top board. FIG. 5A shows the AGV 10 and towing truck 5 before being connected. Each leg of the tow truck 5 is provided with a caster. The AGV 10 is mechanically connected with the towing truck 5 . FIG. 5B shows the AGV 10 and tow truck 5 connected. When the AGV 10 travels, the tow truck 5 is towed by the AGV 10. - 特許庁By towing the tow truck 5, the AGV 10 can transport the load placed on the tow truck 5. - 特許庁

The connection method between the AGV 10 and the towing truck 5 is arbitrary. An example is described here. A plate 6 is fixed to the top plate of the AGV 10 . The towing carriage 5 is provided with a guide 7 having a slit. The AGV 10 approaches the tow truck 5 and inserts the plate 6 into the slit in the guide 7. When the insertion is completed, the AGV 10 causes an electromagnetic locking pin (not shown) to pass through the plate 6 and the guide 7 to apply an electromagnetic lock. As a result, the AGV 10 and the towing truck 5 are physically connected.

Refer to FIG. 3 again. Each AGV 10 and the terminal device 20 are connected, for example, one-to-one, and can perform communication conforming to the Bluetooth (registered trademark) standard. Each AGV 10 and terminal device 20 can also perform Wi-Fi (registered trademark) compliant communication using one or a plurality of access points 2 . A plurality of access points 2 are connected to each other via a switching hub 3, for example. Two access points 2a and 2b are shown in FIG. The AGV 10 is wirelessly connected to the access point 2a. The terminal device 20 is wirelessly connected to the access point 2b. The data transmitted by the AGV 10 is received by the access point 2a, transferred to the access point 2b via the switching hub 3, and transmitted to the terminal device 20 from the access point 2b. Data transmitted by the terminal device 20 is received by the access point 2b, transferred to the access point 2a via the switching hub 3, and transmitted from the access point 2a to the AGV 10. FIG. Thereby, bidirectional communication between the AGV 10 and the terminal device 20 is realized. A plurality of access points 2 are also connected to an operation management device 50 via a switching hub 3 . Thereby, two-way communication is also realized between the operation management device 50 and each AGV 10 .

(2) Creation of environment map A map of the moving space S is created so that the AGV 10 can travel while estimating its own position. The AGV 10 is equipped with a position estimation device and a laser range finder, and the output of the laser range finder can be used to create a map.

The AGV 10 transitions to the data acquisition mode by user's operation. In data acquisition mode, the AGV 10 begins acquiring sensor data using the laser range finder. The laser range finder periodically scans the surrounding space S by radiating, for example, an infrared or visible laser beam to the surroundings. The laser beam is reflected by surfaces such as walls, structures such as pillars, and objects placed on the floor. The laser range finder receives the reflected light of the laser beam, calculates the distance to each reflection point, and outputs measurement result data indicating the position of each reflection point. The position of each reflection point reflects the arrival direction and distance of the reflected light. Data of measurement results is sometimes called "measurement data" or "sensor data".

The position estimation device accumulates sensor data in a storage device. When the acquisition of the sensor data in the movement space S is completed, the sensor data accumulated in the storage device are transmitted to the external device. The external device is, for example, a computer having a signal processor and having a mapping program installed.

A signal processor in the external device superimposes the sensor data obtained for each scan. A map of the space S can be created by repeating the process of superimposition by the signal processor. The external device transmits the created map data to the AGV 10 . The AGV 10 saves the created map data in an internal storage device. The external device may be the operation management device 50 or may be another device.

The AGV 10 may create the map instead of the external device. A circuit such as a microcontroller unit (microcomputer) of the AGV 10 may perform the processing performed by the signal processing processor of the external device described above. When creating a map within the AGV 10, there is no need to transmit the accumulated sensor data to an external device. The data volume of sensor data is generally considered to be large. Since there is no need to transmit sensor data to an external device, occupation of communication lines can be avoided.

It should be noted that the movement within the movement space S for acquiring the sensor data can be realized by the AGV 10 running according to the user's operation. For example, the AGV 10 wirelessly receives a travel command from the user via the terminal device 20 to move in the front, back, left, and right directions. The AGV 10 travels forward, backward, leftward, and rightward in the moving space S according to the travel command to create a map. When the AGV 10 is wired to a control device such as a joystick, the AGV 10 may move forward, backward, left and right in the moving space S according to control signals from the control device to create a map. Sensor data may be acquired by a person pushing a measurement trolley equipped with a laser range finder.

Although a plurality of AGVs 10 are shown in FIGS. 3 and 4, the number of AGVs may be one. When a plurality of AGVs 10 exist, the user 1 can use the terminal device 20 to select one AGV 10 from among the plurality of registered AGVs and create a map of the moving space S.

After the map is created, each AGV 10 can automatically travel while estimating its own position using the map. A description of the process of estimating the self-position will be given later.

(3) Configuration of AGV FIG. 6 is an external view of an exemplary AGV 10 according to this embodiment. The AGV 10 has two driving wheels 11a and 11b, four casters 11c, 11d, 11e and 11f, a frame 12, a carrier table 13, a travel control device 14, and a laser range finder 15. Two drive wheels 11a and 11b are provided on the right and left sides of the AGV 10, respectively. Four casters 11c, 11d, 11e and 11f are arranged at the four corners of the AGV 10. As shown in FIG. Note that the AGV 10 also has motors connected to the two drive wheels 11a and 11b, but the motors are not shown in FIG. FIG. 6 also shows one drive wheel 11a and two casters 11c and 11e positioned on the right side of the AGV 10 and a caster 11f positioned on the left rear, but the left drive wheel 11b and the left front The caster 11d is hidden behind the frame 12 and is not shown. The four casters 11c, 11d, 11e and 11f are freely swivelable. In the following description, the drive wheels 11a and 11b are also referred to as wheels 11a and 11b, respectively.

AGV 10 further comprises at least one obstacle sensor 19 for detecting obstacles. In the example of FIG. 6, four obstacle sensors 19 are provided at four corners of the frame 12 . The number and arrangement of obstacle sensors 19 may differ from the example in FIG. The obstacle sensor 19 can be, for example, an infrared sensor, an ultrasonic sensor, or a device capable of distance measurement, such as a stereo camera. If the obstacle sensor 19 is an infrared sensor, for example, an infrared ray is emitted at regular intervals and the time taken for the reflected infrared ray to return is measured, thereby detecting an obstacle existing within a certain distance. can be done. When the AGV 10 detects an obstacle on the route based on the signal output from at least one obstacle sensor 19, the AGV 10 performs an action to avoid the obstacle.

The travel control device 14 is a device that controls the operation of the AGV 10, and mainly includes an integrated circuit including a microcomputer (described later), electronic components, and a board on which they are mounted. The traveling control device 14 performs data transmission/reception with the terminal device 20 and preprocessing calculations as described above.

The laser range finder 15 is an optical device that measures the distance to a reflection point by emitting an infrared or visible laser beam 15a and detecting the reflected light of the laser beam 15a. In this embodiment, the laser range finder 15 of the AGV 10 emits a pulsed laser beam in a space within a range of 135 degrees to the left and right (270 degrees in total) with respect to the front of the AGV 10, for example, while changing the direction every 0.25 degrees. 15a and detects the reflected light of each laser beam 15a. As a result, it is possible to obtain data on the distance to the reflection point in the direction determined by the angles of 1081 steps in total, every 0.25 degrees. In this embodiment, the scanning of the surrounding space performed by the laser range finder 15 is substantially parallel to the floor surface and planar (two-dimensional). However, the laser range finder 15 may scan in the height direction.

The AGV 10 can create a map of the space S based on the position and orientation (orientation) of the AGV 10 and the scanning result of the laser range finder 15 . The map may reflect the placement of the walls around the AGV, structures such as pillars, and objects placed on the floor. Map data is stored in a storage device provided in the AGV 10 .

Generally, the position and posture of a moving object are called poses. The position and orientation of a moving object in a two-dimensional plane are represented by position coordinates (x, y) in an XY orthogonal coordinate system and an angle θ with respect to the X axis. The position and orientation of the AGV 10, ie pose (x, y, θ), may hereinafter be simply referred to as "position".

The position of the reflection point as seen from the emission position of the laser beam 15a can be expressed using polar coordinates determined by angles and distances. In this embodiment, the laser range finder 15 outputs sensor data expressed in polar coordinates. However, the laser range finder 15 may convert the position expressed in polar coordinates into rectangular coordinates and output the same.

Since the structure and operating principle of laser range finders are well known, no further detailed description is provided herein. Examples of objects that can be detected by the laser range finder 15 are people, luggage, shelves, walls.

The laser range finder 15 is an example of an external sensor for sensing the surrounding space and acquiring sensor data. Image sensors and ultrasonic sensors can be considered as other examples of such external sensors.

The traveling control device 14 can estimate its own current position by comparing the measurement result of the laser range finder 15 and the map data it holds. Note that the stored map data may be map data created by another AGV 10 .

FIG. 7A shows a first hardware configuration example of the AGV 10. As shown in FIG. FIG. 7A also shows a specific configuration of the travel control device 14. As shown in FIG.

The AGV 10 includes a travel control device 14, a laser range finder 15, two motors 16a and 16b, a driving device 17, wheels 11a and 11b, and two rotary encoders 18a and 18b.

The traveling control device 14 has a microcomputer 14a, a memory 14b, a storage device 14c, a communication circuit 14d, and a position estimation device 14e. The microcomputer 14a, the memory 14b, the storage device 14c, the communication circuit 14d, and the position estimation device 14e are connected by a communication bus 14f, and can exchange data with each other. The laser range finder 15 is also connected to the communication bus 14f via a communication interface (not shown), and transmits measurement data, which are measurement results, to the microcomputer 14a, the position estimation device 14e and/or the memory 14b.

The microcomputer 14a is a processor or control circuit (computer) that performs calculations for controlling the entire AGV 10 including the travel control device 14. FIG. The microcomputer 14a is typically a semiconductor integrated circuit. The microcomputer 14a transmits a PWM (Pulse Width Modulation) signal, which is a control signal, to the driving device 17 to control the driving device 17 and adjust the voltage applied to the motor. This causes each of the motors 16a and 16b to rotate at the desired rotational speed.

One or more control circuits (for example, microcomputers) for controlling the driving of the left and right motors 16a and 16b may be provided independently of the microcomputer 14a. For example, the motor driving device 17 may include two microcomputers that respectively control the driving of the motors 16a and 16b. These two microcomputers may perform coordinate calculations using encoder information output from encoders 18a and 18b, respectively, to estimate the movement distance of AGV 10 from a given initial position. Also, the two microcomputers may control the motor drive circuits 17a and 17b using the encoder information.

The memory 14b is a volatile storage device that stores computer programs executed by the microcomputer 14a. The memory 14b can also be used as a work memory when the microcomputer 14a and the position estimation device 14e perform calculations.

The storage device 14c is a non-volatile semiconductor memory device. However, the storage device 14c may be a magnetic recording medium typified by a hard disk, or an optical recording medium typified by an optical disc. Further, the storage device 14c may include a head device for writing data to and/or reading data from any recording medium and a control device for the head device.

The storage device 14c stores map data M of the space S in which the vehicle travels, and data R of one or more travel routes (travel route data). The map data M are created by the AGV 10 operating in the map creation mode and stored in the storage device 14c. The travel route data R is transmitted from the outside after the map data M is created. Although the map data M and the travel route data R are stored in the same storage device 14c in this embodiment, they may be stored in different storage devices.

An example of travel route data R will be described.

If the terminal device 20 is a tablet computer, the AGV 10 receives travel route data R indicating a travel route from the tablet computer. The travel route data R at this time includes marker data indicating the positions of a plurality of markers. A "marker" indicates a passing position (way point) of the traveling AGV 10 . The travel route data R includes at least position information of a start marker indicating a travel start position and an end marker indicating a travel end position. The travel route data R may further include position information of markers of one or more intermediate waypoints. When the travel route includes one or more intermediate waypoints, the route from the start marker to the end marker via the travel waypoints in order is defined as the travel route. The data of each marker can include the direction (angle) and travel speed data of the AGV 10 until it moves to the next marker, in addition to the coordinate data of that marker. When the AGV 10 temporarily stops at the position of each marker and performs self-position estimation and notification to the terminal device 20, etc., the data of each marker is the acceleration time required for acceleration to reach the running speed, and / or , data of the deceleration time required for deceleration from the running speed to stop at the position of the next marker.

The movement of the AGV 10 may be controlled by the operation management device 50 (eg, PC and/or server computer) instead of the terminal device 20 . In that case, the operation management device 50 may instruct the AGV 10 to move to the next marker each time the AGV 10 reaches the marker. For example, the AGV 10 receives, from the operation control device 50, the coordinate data of the next target position, or the data of the distance to the target position and the angle to be traveled, as the travel route data R indicating the travel route.

The AGV 10 can travel along the stored travel route while estimating its own position using the created map and the sensor data output by the laser range finder 15 acquired during travel.

The communication circuit 14d is, for example, a wireless communication circuit that performs wireless communication conforming to the Bluetooth (registered trademark) and/or Wi-Fi (registered trademark) standards. Both standards include wireless communication standards using frequencies in the 2.4 GHz band. For example, in a mode in which the AGV 10 is driven to create a map, the communication circuit 14d performs wireless communication conforming to the Bluetooth (registered trademark) standard and communicates with the terminal device 20 on a one-to-one basis.

The position estimation device 14e performs map creation processing and self-position estimation processing during travel. The position estimation device 14e creates a map of the moving space S based on the position and orientation of the AGV 10 and the scan result of the laser range finder. During traveling, the position estimation device 14e receives sensor data from the laser range finder 15, and reads map data M stored in the storage device 14c. By matching the local map data (sensor data) created from the scanning result of the laser range finder 15 with the wider map data M, the self-position (x, y, θ) on the map data M is determined. identify. The position estimator 14e generates "reliability" data representing the extent to which the local map data matches the map data M. FIG. Self-position (x, y, θ) and reliability data can be transmitted from the AGV 10 to the terminal device 20 or the operation management device 50 . The terminal device 20 or the operation management device 50 can receive the self-position (x, y, θ) and reliability data and display them on a built-in or connected display device.

In this embodiment, the microcomputer 14a and the position estimation device 14e are separate components, but this is just an example. A single chip circuit or a semiconductor integrated circuit capable of independently performing each operation of the microcomputer 14a and the position estimation device 14e may be used. FIG. 7A shows a chip circuit 14g that encompasses the microcomputer 14a and the position estimator 14e. An example in which the microcomputer 14a and the position estimation device 14e are provided independently will be described below.

Two motors 16a and 16b are attached to the two wheels 11a and 11b respectively to rotate each wheel. That is, the two wheels 11a and 11b are drive wheels respectively. Motors 16a and 16b are described herein as being motors that drive the right and left wheels of AGV 10, respectively.

The moving body 10 further comprises an encoder unit 18 for measuring the rotational positions or rotational speeds of the wheels 11a and 11b. The encoder unit 18 includes a first rotary encoder 18a and a second rotary encoder 18b. The first rotary encoder 18a measures rotation at any position of the power transmission mechanism from the motor 16a to the wheels 11a. The second rotary encoder 18b measures rotation at any position of the power transmission mechanism from the motor 16b to the wheels 11b. The encoder unit 18 transmits signals obtained by the rotary encoders 18a and 18b to the microcomputer 14a. The microcomputer 14a may control the movement of the moving body 10 using not only the signal received from the position estimation device 14e but also the signal received from the encoder unit 18. FIG.

The drive device 17 has motor drive circuits 17a and 17b for adjusting the voltage applied to each of the two motors 16a and 16b. Each of motor drive circuits 17a and 17b includes a so-called inverter circuit. The motor drive circuits 17a and 17b turn on or off the current flowing through each motor according to the PWM signal sent from the microcomputer 14a or the microcomputer in the motor drive circuit 17a, thereby adjusting the voltage applied to the motor.

FIG. 7B shows a second hardware configuration example of the AGV 10. As shown in FIG. The second hardware configuration example differs from the first hardware configuration example (FIG. 7A) in that it has a laser positioning system 14h and that the microcomputer 14a is connected to each component on a one-to-one basis. do.

The laser positioning system 14 h has a position estimation device 14 e and a laser range finder 15 . The position estimation device 14e and the laser range finder 15 are connected, for example, by an Ethernet (registered trademark) cable. Each operation of the position estimation device 14e and the laser range finder 15 is as described above. The laser positioning system 14h outputs information indicating the pose (x, y, θ) of the AGV 10 to the microcomputer 14a.

The microcomputer 14a has various general-purpose I/O interfaces or general-purpose input/output ports (not shown). The microcomputer 14a is directly connected to other components in the travel control device 14, such as the communication circuit 14d and the laser positioning system 14h, via the general-purpose input/output port.

The configuration is common to that of FIG. 7A except for the configuration described above with respect to FIG. 7B. Therefore, the description of the common configuration is omitted.

The AGV 10 in embodiments of the present disclosure may include safety sensors, such as bumper switches, not shown. The AGV 10 may be equipped with an inertial measurement device such as a gyro sensor. Using data measured by internal sensors such as rotary encoders 18a and 18b or an inertial measurement device, it is possible to estimate the movement distance and attitude change amount (angle) of the AGV 10 . These range and angle estimates are referred to as odometry data and may serve to supplement the position and attitude information obtained by the position estimator 14e.

(4) Map data FIGS. 8A to 8F schematically show the AGV 10 moving while acquiring sensor data. The user 1 may manually move the AGV 10 while operating the terminal device 20 . Alternatively, the sensor data may be acquired by placing the unit including the travel control device 14 shown in FIGS. 7A and 7B or the AGV 10 itself on a cart and pushing or pulling the cart by the user 1. .

FIG. 8A shows AGV 10 scanning the surrounding space using laser range finder 15 . A laser beam is emitted at each predetermined step angle to perform scanning. It should be noted that the illustrated scan range is an example schematically shown, and is different from the total scan range of 270 degrees described above.

In each of FIGS. 8A-8F, the positions of the reflection points of the laser beam are schematically indicated using a plurality of black dots 4 represented by symbols "." The scanning of the laser beam is performed at short intervals while the position and posture of the laser range finder 15 are changed. Therefore, the actual number of reflection points is much larger than the number of reflection points 4 shown. The position estimating device 14e accumulates the positions of the black spots 4 obtained as the vehicle travels, for example, in the memory 14b. Map data is gradually completed by continuously scanning while the AGV 10 is traveling. Only the scan range is shown in FIGS. 8B-8E for simplicity. The scan range is an example, and differs from the total 270 degree example described above.

A map may be created using the microcomputer 14a in the AGV 10 or an external computer based on the sensor data obtained after acquiring the necessary amount of sensor data for creating the map. Alternatively, a map may be created in real time based on sensor data acquired by the AGV 10 while it is moving.

FIG. 8F schematically shows a portion of the completed map 40. FIG. In the map shown in FIG. 8F, free space is partitioned by Point Clouds corresponding to collections of reflection points of laser beams. Another example of a map is an occupancy grid map that distinguishes between space occupied by objects and free space by grid units. The position estimation device 14e accumulates map data (map data M) in the memory 14b or the storage device 14c. Note that the illustrated number or density of black dots is an example.

The map data thus obtained can be shared by multiple AGVs 10 .

A typical example of an algorithm by which the AGV 10 estimates its own position based on map data is ICP (Iterative Closest Point) matching. As described above, the local map data (sensor data) created from the scanning results of the laser range finder 15 is matched with the wider map data M to obtain the self-position (x, y, θ) can be estimated.

When the area in which the AGV 10 travels is large, the data amount of the map data M increases. Therefore, there is a possibility that problems such as an increase in map creation time and a long time required for self-position estimation may occur. If such an inconvenience occurs, the map data M may be created and recorded by dividing it into a plurality of partial map data.

FIG. 9 shows an example in which an entire floor of one factory is covered by a combination of four partial map data M1, M2, M3, and M4. In this example, one piece of partial map data covers an area of 50m x 50m. A rectangular overlapping area with a width of 5 m is provided at the boundary between two adjacent maps in each of the X and Y directions. This overlapping area is called a "map switching area". When the AGV 10 traveling while referring to one partial map reaches a map switching area, the AGV 10 switches to traveling while referring to another adjacent partial map. The number of partial maps is not limited to four, and may be set as appropriate according to the area of the floor on which the AGV 10 runs, and the performance of the computer that executes map creation and self-position estimation. The size of the partial map data and the width of the overlapping area are also not limited to the above examples, and may be set arbitrarily.

(5) Configuration Example of Traffic Control Device FIG. 10 shows an example of hardware configuration of the traffic control device 50. As shown in FIG. The operation management device 50 has a CPU 51 , a memory 52 , a position database (position DB) 53 , a communication circuit 54 , a map database (map DB) 55 and an image processing circuit 56 .

The CPU 51, memory 52, position DB 53, communication circuit 54, map DB 55, and image processing circuit 56 are connected by a communication bus 57, and can exchange data with each other.

The CPU 51 is a signal processing circuit (computer) that controls the operation of the operation management device 50 . The CPU 51 is typically a semiconductor integrated circuit.

The memory 52 is a volatile storage device that stores computer programs executed by the CPU 51 . The memory 52 can also be used as a work memory when the CPU 51 performs calculations.

The position DB 53 stores position data indicating each potential destination of each AGV 10 . The position data may be represented by coordinates set virtually within the factory by an administrator, for example. Location data is determined by an administrator.

Communication circuit 54 performs wired communication conforming to the Ethernet (registered trademark) standard, for example. The communication circuit 54 is connected to the access point 2 ( FIG. 3 ) by wire, and can communicate with the AGV 10 via the access point 2 . The communication circuit 54 receives data to be transmitted to the AGV 10 from the CPU 51 via the bus 57 . The communication circuit 54 also transmits data (notification) received from the AGV 10 to the CPU 51 and/or the memory 52 via the bus 57 .

The map DB 55 stores map data of the inside of a factory or the like where the AGV 10 travels. The map may be the same as map 40 (FIG. 8F) or may be different. The data format does not matter as long as the map has a one-to-one correspondence with the position of each AGV 10 . For example, the map stored in the map DB 55 may be a map created by CAD.

The position DB 53 and the map DB 55 may be constructed on a non-volatile semiconductor memory, or may be constructed on a magnetic recording medium typified by a hard disk, or an optical recording medium typified by an optical disc.

The image processing circuit 56 is a circuit that generates image data to be displayed on the monitor 58 . The image processing circuit 56 operates exclusively when the manager operates the operation management device 50 . In this embodiment, a more detailed description is omitted. Note that the monitor 59 may be integrated with the operation management device 50 . Alternatively, the processing of the image processing circuit 56 may be performed by the CPU 51 .

(6) Operation of Operation Management Device An outline of the operation of the operation management device 50 will be described with reference to FIG. FIG. 11 is a diagram schematically showing an example of the moving route of the AGV 10 determined by the operation management device 50. As shown in FIG.

An overview of the operations of the AGV 10 and the operation management device 50 is as follows. In the following, an example will be described in which an AGV 10 is currently at position M1, passes through several positions, and travels to its final destination, position _{Mn+1 (} where n is a positive integer equal to or greater than 1). . The position DB 53 records coordinate data indicating each position such as a position M ₂ to be passed next to the position M ₁ and a position M ₃ to be passed next to the position M ₂ .

The CPU 51 of the operation management device 50 refers to the position DB 53, reads out the coordinate data of the position _M2 , and generates a travel command for heading to the position _M2 . A communication circuit 54 transmits a travel command to the AGV 10 via the access point 2 .

The CPU 51 periodically receives data indicating the current position and orientation from the AGV 10 via the access point 2 . In this way, the operation management device 50 can track the position of each AGV 10 . When the CPU 51 determines that the current position of the AGV ₁₀ coincides with the position M2, the CPU 51 reads the coordinate data of the position M3, generates a travel command for heading to the position M3 _, and transmits it to the _AGV10 . That is, when the operation management device 50 determines that the AGV 10 has reached a certain position, it transmits a travel command to direct the AGV 10 to the position to be passed next. This allows the AGV 10 to reach the final target position _Mn+1 . The above-described passing position and target position of the AGV 10 are sometimes called "markers".

(7) Example of AGV Operation Next, a more specific example of the operation of the AGV 10 will be described.

FIG. 12 schematically shows the 10 that conveys the work 80. As shown in FIG. In this embodiment, the work 80 is temporarily placed (relocated) on a rack, which will be described later, so that the work 80 is longer than the transport table 13 in a predetermined direction. In the example of FIG. 12, the workpiece 80 is longer than the carrier table 13 in the vehicle width direction perpendicular to the traveling direction of the AGV 10 indicated by the arrow. The workpiece 80 may be longer than the carrier table 13 with respect to the traveling direction or other directions.

13A and 13B show time-series changes in the position and attitude of the AGV 10 operating according to this embodiment. In order to clarify the orientation of the work 80 during transportation, a notch is provided at one corner of the rectangle showing the work 80 .

First, refer to FIG. 13A. The following operations of the AGV 10 are realized under the control of the microcomputer 14a corresponding to the controller 105 (FIG. 1).

Initially, AGV 10 receives workpiece 80 discharged from conveyor 200 at position P1. After that, the AGV 10 moves to the position P2 where the rack 210 is installed. A rack 210 is installed in advance at the position P2. Movement of the AGV 10 is performed using the position estimated by the position estimation device 14e. However, the AGV 10 may not have the position estimating device 14e, and may run according to a predetermined operation pattern, for example. Upon reaching the position P2, the workpiece 80 is transferred to the rack 210. FIG. The AGV 10 then turns in place.

FIG. 14A shows the AGV 10 heading for the rack 210 while conveying the work 80. FIG. In the exemplary embodiment, rack 210 is a structure assembled by multiple frames. For reference, the X, Y and Z axes are shown.

The rack 210 has an opening 212 with a predetermined width in the X-axis direction. In this embodiment, the "predetermined width" is shorter than the workpiece 80 in the X-axis direction. Also, the position of the lower surface of the workpiece 80 in the opening 212 approximately matches the height of the rack 210 . Further, in this embodiment, the frame 214 is inclined in the +Z-axis direction from the opening 212 of the rack 210 toward the Y-axis direction. As a result, when the AGV 10 carrying the workpiece 80 enters the inside of the rack 210 through the opening 212, the workpiece 80 is supported by the two horizontal bars of the rack 210 in the Y-axis direction, and eventually leaves the carrier table 13 of the AGV 10. , is moved onto the rack 210 . FIG. 14B shows the workpiece 80 transferred to the rack 210. FIG.

In the state of FIG. 14B, the AGV 10 turns clockwise K degrees on the spot. An example of "K degrees" is -90 degrees (90 degrees in the clockwise direction) when the counterclockwise direction is positive. Thereby, the orientation of the traveling direction of the AGV 10 can be changed.

After turning K degrees, the AGV 10 comes out of the rack 210 through the opening 212 again. On the way, the carrier table 13 and the workpiece 80 come into contact with each other again, and eventually the AGV 10 receives the workpiece 80 again on the carrier table 13 . FIG. 14C shows the AGV 10 receiving a workpiece 80 and reoriented. The direction of travel is indicated by an arrow. Note that the moving route of the AGV 10 is illustrated by a dashed line.

See FIG. 13B. The AGV 10, which has placed the work 80 again on the transport table 13, then travels toward the position P3. A position P3 is a transfer position of the work 80, and is a supply port of the work 80 to another conveyor 220, for example. Upon reaching position P3, AGV 10 delivers workpiece 80 to conveyor 220. As shown in FIG. The handover process can be performed using, for example, a robot arm installed at position P3.

By providing a rack 210 at the position P2, temporarily placing the work 80 and rotating the AGV 10, the orientation of the work 80 when received at the position P1 and the orientation of the work 80 when handed over at the position P3 can be changed. was made. As a result, even if the delivery direction of the work 80 to the conveyor 220 at the position P<b>3 differs from the discharge direction of the conveyor 200 , the work 80 can be appropriately supplied to the conveyor 220 . By using a very simple structure (rack 210) and the basic operation of the AGV 10, it was possible to realize a mechanism for changing the orientation of the workpiece at low cost.

Next, a method for changing the orientation of the workpiece 80 using different mechanisms will be described.

FIG. 15 shows the AGV 10 on which the lifter mechanism 19 is mounted. In the exemplary embodiment, the lifter mechanism 19 is an elevating device that horizontally raises and lowers the transport table 13 by extending and retracting one or more X-shaped arms (for example, arms 19a and 19b) by a motor or hydraulic cylinder (not shown). is. The illustrated lifter mechanism 19 is sometimes called a pantograph lifter. Since the lifter mechanism 19 is well known, further detailed description thereof is omitted in this specification. In this embodiment, the up-and-down operation of the lifter mechanism 19 is controlled by the microcomputer 14a.

The operation performed by the AGV 10 having the lifter mechanism 19 at the position P2 (FIGS. 13A and 13B) will be described below with reference to FIGS. 16A to 16H. Operations other than position P2 are the same as those described with reference to FIGS. 13A and 13B and the like. Therefore, the explanation for the second time is omitted. The configuration of the rack 210 and the dimensions of the carrier table 13, workpiece 80, and rack 210 in the X-axis direction are the same as those described above, unless otherwise specified.

FIG. 16A is a side view showing the relationship between the AGV 10 that transports the workpiece 80 and the rack 210. FIG. For reference, the X, Y and Z axes are shown. Note that in the example shown in FIGS. 16A-16H, the frame 214 of the rack 210 is parallel to the Y-axis.

16B shows the AGV 10 with the lifter mechanism 19 extended away from the rack 210. FIG. With respect to the Z-axis direction, the position of the lower surface of the workpiece 80 is higher than the surface of the frame 214 on the +Z-axis side. In this state, AGV 10 runs toward opening 212 of rack 210 .

FIG. 16C shows AGV 10 entering opening 212 of rack 210 . The lifter mechanism 19 remains in an extended state.

FIG. 16D shows the AGV 10 with the carrier table 13 lowered. The workpiece 80 is transferred onto the rack 210 by lowering the carrier table 13 .

FIG. 16E shows the AGV 10 turned 90 degrees clockwise in place. Work 80 is still placed on rack 210 .

FIG. 16F shows the AGV 10 with the lifter mechanism 19 extended. The lifting operation of the lifter mechanism 19 brings the transfer table 13 of the AGV 10 into contact with the workpiece 80 from the -Z direction and lifts the workpiece 80 from the rack 210 .

FIG. 16G shows the AGV 10 rotated another 90 degrees clockwise in place. The workpiece 80 rotates clockwise by 90 degrees as the AGV 10 rotates.

16H shows AGV 10 exiting opening 212 of rack 210. FIG. Thereafter, the AGV 10 lowers the lifter mechanism 19 and travels to position P3.

Due to the above operation, the orientation of the workpiece 80 changes by 90 degrees before and after reaching the position P2. 16B and 16H show workpieces 80 with different orientations. By providing the lifter mechanism 19 to temporarily deposit the workpiece 80 on the rack 210 and rotating the AGV 10 during that time, a very simple structure (the rack 210) and the basic structure of the AGV 10 can be obtained, as in the example described above. A mechanism for changing the orientation of the workpiece can be realized at low cost by the operation.

Note that in this example, the AGV 10 performs two turning motions (FIGS. 16E and 16G). However, these are only examples. If the AGV 10 can escape from the opening 212 along the path shown in FIG. 14C, the second turning motion can be omitted.

The mobile body and mobile body management system of the present disclosure can be suitably used for moving and transporting goods such as packages, parts, and finished products in factories, warehouses, construction sites, logistics, hospitals, and the like.

80 work (object to be transported) 100 mobile body management system 101 mobile body 103 carrier table 105 controller 107 drive device

Claims (10)

A work transfer method using a moving body,
The moving body can move autonomously and has a transport table on which the work is placed when the work is transported,
The conveying method is
(a) at a first position, causing the moving body to receive a work oriented on a carrier table in a first direction with respect to the traveling direction of the moving body ;
(b) moving the moving body to a second position where the rack is installed;
(c) causing the movable body to transfer the workpiece to the rack at the second position;
(d) causing the moving body to change the orientation of the moving body at the second position after the work is transferred;
(e) changing the orientation of the work with respect to the traveling direction of the mobile body to a second direction different from the first orientation by causing the mobile body to receive the work transferred to the rack on the carrier table; in the direction of
(f) moving the moving body to a third position;
(g) A work conveying method , wherein the work is delivered at the third position. at the second position,
The workpiece placed on the carrier table is longer than the carrier table in a predetermined direction,
The rack has an opening that is shorter than the work in the predetermined direction and wider than the transfer table,
The step (c) is a step of moving the work to the rack by causing the moving body to enter the opening and supporting the work on the rack at the second position in the opening. The conveying method according to claim 1. The moving body has a lifter mechanism that moves the transport table up and down,
3. The transfer method according to claim 1, wherein said step (c) is a step of transferring said workpiece to said rack by said moving body raising and/or lowering said lifter mechanism. 4. The transfer method according to any one of claims 1 to 3, wherein said step (g) is a step of transferring said workpiece by said moving body raising and/or lowering said lifter mechanism. The direction in which the work is handed over in the step (g) is predetermined,
5. The transfer method according to any one of claims 1 to 4, wherein said step (d) is a step of changing the direction of said moving body according to said direction in which said work is handed over. 6. The transfer method according to claim 5, wherein said step (d) is a step of rotating said moving body to change the direction of said moving body. 7. The conveying method according to any one of claims 1 to 6, wherein said step (a) is a step of causing said moving body to receive said work discharged from a first conveyor at said first position. The step (g) is a step of transferring the workpiece at the third position to a second conveyor different from the first conveyor, wherein the transferring direction of the workpiece to the second conveyor is the third conveyor. 8. The transfer method according to claim 7, wherein the process is different from the direction in which the work is discharged from one conveyor. A computer program for causing a controller of the moving body to execute the transportation method according to any one of claims 1 to 8 . A mobile body that can move autonomously,
a driving device for moving the moving body;
a controller that controls the driving device to move the moving body;
and a carrier table,
The controller is
At the first position, receiving a work on the carrier table in a first direction with respect to the traveling direction of the moving body ;
moving the moving body to a second position where the rack is installed;
transferring the workpiece to the rack at the second position;
changing the orientation of the moving body at the second position after transferring the work;
causing the work transferred to the rack to be received on the carrier table so that the work is oriented in a second direction different from the first direction with respect to the traveling direction of the moving body;
moving the moving body to a third position;
hand over the workpiece at the third position
, mobile.

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