JP2019067001A - Moving body - Google Patents

Abstract

To reduce the time required to create an environmental map of a moving body.SOLUTION: A moving body 10 includes; an external sensor 101 that periodically scans the environment and outputs sensor data for each scan; an internal sensor 103 for detecting a moving distance or a moving speed of the moving body; a control circuit 105 and a storage device 107 connected to the external sensor and the internal sensor. Among the sensor data output from the external sensor, the scanned sensor data which is selected according to the moving distance or the moving speed detected by the internal sensor is stored in the storage device as map creation data by the control circuit.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to mobiles.

  Research and development of autonomously moving mobile bodies such as unmanned transport vehicles or mobile robots are in progress. In order for a mobile to move autonomously, it is necessary to recognize its own position. The self position can be estimated by performing matching between map data prepared in advance and data acquired using an external sensor such as a laser range finder. An example of such a method of self-position estimation is disclosed in, for example, Japanese Patent Laid-Open No. 2008-250906.

JP 2008-250906 A

  The present disclosure provides a technique for reducing the time required to create a map used for self-position estimation.

  The mobile in the exemplary embodiment of the present disclosure periodically scans the environment, and an external sensor that outputs sensor data for each scan, and an internal sensor that detects the moving distance or moving speed of the mobile. A control circuit connected to the external sensor and the internal sensor; and a storage device. The control circuit is configured to use, as the data for map creation, sensor data by scanning selected from the sensor data output from the external sensor and the moving distance detected by the internal sensor or the moving speed. Store in storage device.

  The above general aspects may be realized by a system, a method, an integrated circuit, a computer program, or a storage medium. Alternatively, the present invention may be realized by any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a storage medium.

  According to the embodiment of the present disclosure, only a part of sensor data periodically output from the external sensor is used as map creation data. Therefore, the time required for map creation can be shortened.

FIG. 1 is a block diagram showing a schematic configuration of a mobile unit 10 in an exemplary embodiment of the present disclosure. FIG. 2A is a diagram showing an example of the relationship between the movement distance and the recording timing of the mapping data in a comparative example in which the mapping data is recorded at a constant cycle. FIG. 2B is a diagram showing an example of the relationship between the movement distance and the recording timing of the data for map generation in the embodiment in which the data for map generation is recorded for each fixed movement distance. FIG. 3 is a diagram showing an example of the relationship between the movement distance of the moving body 10 measured by the rotary encoder and the elapsed time. FIG. 4 is a diagram showing an example of data recorded in the storage device 107 in the example of FIG. FIG. 5 is a flowchart showing an example of a map creation method by the mobile object 10. FIG. 6 is a diagram showing an outline of a control system that controls traveling of each AGV according to the present disclosure. FIG. 7 is a view showing an example of a moving space S in which an AGV is present. FIG. 8A shows the AGV and tow truck before being connected. FIG. 8B shows the connected AGV and tow truck. FIG. 9 is an external view of an exemplary AGV according to the present embodiment. FIG. 10A is a diagram showing an example of a first hardware configuration of an AGV. FIG. 10B is a diagram showing an example of a second hardware configuration of the AGV. FIG. 11A is a diagram showing an AGV that generates a map while moving. FIG. 11B is a diagram showing an AGV that generates a map while moving. FIG. 11C is a diagram showing an AGV that generates a map while moving. FIG. 11D is a diagram showing an AGV that generates a map while moving. FIG. 11E is a diagram showing an AGV that generates a map while moving. FIG. 11F is a view schematically showing a part of the completed map. FIG. 12 is a diagram showing an example in which a map of one floor is configured by a plurality of partial maps. FIG. 13 is a diagram illustrating an example of a hardware configuration of the operation management device. FIG. 14 is a view schematically showing an example of the AGV movement route determined by the operation management device.

<Term>
Before describing the embodiments of the present disclosure, definitions of terms used in the present specification will be described.

  The term "unmanned transport vehicle" (AGV) means a trackless vehicle that manually or automatically loads a load on a main body, travels automatically to a designated location, and unloads manually or automatically. "Unmanned aerial vehicle" includes unmanned tow vehicles and unmanned forklifts.

  The term "unmanned" means that the steering of the vehicle does not require a person, and does not exclude that the unmanned carrier conveys a "person (e.g., a person who unloads a package)".

  The "unmanned tow truck" is a trackless vehicle that is to automatically travel to a designated location by towing a cart for manual or automatic loading and unloading of luggage.

  The "unmanned forklift" is a trackless vehicle equipped with a mast for raising and lowering a load transfer fork and the like, automatically transferring the load to the fork and the like and automatically traveling to a designated location and performing an automatic load handling operation.

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

  A "mobile" is a device that moves while carrying a person or a load, and includes a driving device such as a wheel, a biped or multi-legged walking device, or a propeller that generates a traction for movement. The term "mobile" in the present disclosure includes mobile robots and drone as well as unmanned transport vehicles in a narrow sense.

  The “automatic traveling” includes traveling based on an instruction of an operation management system of a computer to which the automated guided vehicle is connected by communication, and autonomous traveling by a control device provided in the automated guided vehicle. The autonomous traveling includes not only traveling by the automated guided vehicle toward a destination along a predetermined route, but also traveling by following a tracking target. In addition, the automatic guided vehicle may perform manual traveling temporarily based on the instruction of the worker. Although "automatic travel" generally includes both "guided" travel and "guideless" travel, in the present disclosure, "guideless" travel is meant.

  The “guided type” is a system in which a derivative is installed continuously or intermittently and a guided vehicle is guided using the derivative.

  The “guideless type” is a method of guiding without installing a derivative. The unmanned transfer vehicle in the embodiment of the present disclosure includes a self position estimation device, and can travel in a guideless manner.

  The “self-position estimation device” is a device that estimates the self-location on the environment 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 external state of the mobile object. The external sensor includes, for example, a laser range finder (also referred to as a range sensor), a camera (or an image sensor), LIDAR (Light Detection and Ranging), a millimeter wave radar, and a magnetic sensor.

  The “internal sensor” is a sensor that senses the internal state of the mobile object. The internal sensors include, for example, a rotary encoder (hereinafter, may be simply referred to as an "encoder"), an acceleration sensor, and an angular acceleration sensor (for example, a gyro sensor).

  "SLAM (Slam)" is an abbreviation for Simultaneous Localization and Mapping, and means that self-localization and environmental mapping are simultaneously performed.

Exemplary Embodiment
Hereinafter, an example of a mobile unit and a mobile unit system according to the present disclosure will be described with reference to the accompanying drawings. In addition, detailed description more than necessary may be omitted. For example, detailed description of already well-known matters and redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. The inventors provide the attached drawings and the following description so that those skilled in the art can fully understand the present disclosure. They are not intended to limit the subject matter recited in the claims.

  FIG. 1 is a block diagram showing a schematic configuration of a mobile unit 10 in an exemplary embodiment of the present disclosure. The movable body 10 includes an external sensor 101, an internal sensor 103, a control circuit 105, and a storage device 107. The external sensor 101 periodically scans the environment, and outputs sensor data (hereinafter also referred to as “scan data”) for each scan. The internal sensor 103 detects the moving distance or moving speed of the moving body 10. The control circuit 105 is connected to the external sensor 101 and the internal sensor 103 and controls the operation of the mobile unit 10. The control circuit 105 causes sensor data of a scan selected according to the moving distance or moving speed detected by the internal sensor 103 among the sensor data output from the external sensor 101 to the storage device 107 as map creation data. Remember.

  The external sensor 101 may be, for example, a sensor that senses the external environment, such as a laser range finder, a camera, a radar, or a LIDAR. The internal sensor 103 may include, for example, a plurality of rotary encoders that respectively detect rotations of a plurality of wheels included in the moving body 10.

  According to the present embodiment, a map is created using only a part of scan data selected according to the detected movement distance or movement speed out of the scan data periodically output from the external sensor 101. Be done. For this reason, compared with the case where a map is created using all the scan data, the time required for map creation can be shortened.

  According to the conventional general map creation method, a map is created using the scan data periodically output from the laser range finder as it is. However, the scan data acquired when the mobile unit 10 is moving at a low speed contains much excess data. If a map is created using such excess scan data, it will take a lot of time to calculate. In the worst case, situations may occur in which the operation does not finish within an acceptable time.

  Therefore, the control circuit 105 in the present embodiment changes the frequency of acquisition of scan data used for map creation according to the moving speed of the moving object 10. For example, the control circuit 105 records scan data as mapping data more frequently as the moving speed of the mobile object 10 is higher. In other words, when the moving body 10 is moving, the number of scans selected by the control circuit 105 per unit time may be a monotonically increasing function of the moving speed of the moving body 10. In one example, the control circuit 105 causes the storage device 107 to store sensor data from a scan selected each time the mobile object 10 moves a fixed distance as map creation data.

  FIG. 2A is a diagram showing an example of the relationship between the movement distance and the recording timing of the mapping data in a comparative example in which the mapping data is recorded at a constant cycle. FIG. 2B is a diagram showing an example of the relationship between the movement distance and the recording timing of the data for map generation in the embodiment in which the data for map generation is recorded for each fixed movement distance. The arrows in the figure indicate the timing at which the map creation data is recorded.

  In the comparative example shown in FIG. 2A, sensor data output from the laser range finder in a fixed cycle (for example, a cycle of 25 ms) is recorded as it is as map creation data. In this case, as the moving speed of the mobile unit 10 is lower, the frequency of data recording is higher, and excess data is easily accumulated. At the time of acquisition of the data for map preparation, the mobile unit 10 is moved along the operation route by pushing the mobile unit 10 by hand or operating the operation terminal. For this reason, the velocity of the moving body 10 may not be constant, and sometimes the moving velocity may be a low velocity close to zero. In that case, a large amount of excess data is accumulated, which causes an increase in calculation time required for map creation.

  On the other hand, in the embodiment shown in FIG. 2B, regardless of the speed of the moving object 10, scan data selected every time it travels a fixed distance is recorded as map creation data. For example, when the moving object 10 is moving at the maximum speed (e.g., 1000 mm / s), the distance (e.g., 25 mm) to be advanced during the scan cycle (e.g., 25 ms) can be the above-described fixed distance. . In this case, regardless of the speed of the moving body 10, for example, map generation data is recorded every 25 mm. Therefore, unlike the comparative example, excessive cartographic data is not accumulated at low speed. Since the amount of mapping data can be reduced to an appropriate amount, the time required for mapping can be shortened.

  The control circuit 105 in the present embodiment stores sensor data (hereinafter sometimes referred to as “selected scan data”) by the selected scan in the storage device 107. The control circuit 105 may store, in the storage device 107, sensor data (hereinafter sometimes referred to as "unselected scan data") by a scan that has not been selected, or discards without storing. It is also good.

  When the scan data not selected is recorded in the storage device 107 together with the selected scan data, the control circuit 105 distinguishes and records both. For example, the control circuit 105 may associate a code (hereinafter, also referred to as an “effective flag”) indicating that the selected scan data is mapping data. Alternatively, the control circuit 105 may record the selected scan data in a different storage area (for example, a different folder) of the storage device 107. For example, the control circuit 105 may record the selected scan data in the first area of the storage device 107, and may store the non-selected scan data in the second area of the storage device 107.

  Hereinafter, an example of a scan data recording method will be described with reference to FIGS. 3 and 4.

  FIG. 3 is a diagram showing an example of the relationship between the movement distance of the moving body 10 measured by the rotary encoder and the elapsed time. FIG. 4 is a diagram showing an example of data recorded in the storage device 107 in the example of FIG. In this example, scan data is output from the laser range finder every 25 ms. Each scan data is a set of coordinate values in a coordinate system (u-v coordinate system) fixed to the mobile object 10. The output scan data is recorded in the storage device 107. At this time, every time the mobile unit 10 moves 25 mm, the scan data immediately after that moves with a valid flag and is recorded. Therefore, as shown in FIG. 4, the scan data immediately after the moving distance exceeds a multiple of 25 mm is recorded with a valid flag. In FIG. 3, the timing at which the valid flag is added and recorded is represented by a circle.

  When creating the environmental map, the control circuit 105 reads the data for map creation from the storage device 107 and performs matching of sensor data included in the data for map creation. Thereby, sensor data can be connected and an environmental map can be created. Note that the creation of the environment map may be performed by another device different from the control circuit 105. Also, the mobile object 10 for creating an environmental map may be different from the mobile object for performing autonomous movement using the environmental map. The mobile unit 10 for creating the environmental map may not have the mechanism capable of autonomous movement.

  The control circuit 105 may change the acquisition method of the cartographic data in accordance with whether or not the mobile object 10 is turning. For example, when moving object 10 goes straight, scan data selected every time it moves a fixed distance is recorded as data for map creation, and when moving object 10 turns, scan data selected every constant time It may be recorded as map creation data. In other words, when the moving body 10 is turning, the number of scans selected by the control circuit 105 per unit time may be a predetermined value exceeding zero. Whether or not the moving body 10 is turning can be determined based on the output of the internal sensor 103.

  FIG. 5 is a flowchart showing an example of a map creation method by the mobile object 10. In this example, the mobile unit 10 starts the map creation mode in step S101. The map creation mode can be started by releasing the brake of the traveling motor, for example, when the moving body 10 moves by manual operation. In addition, when the mobile unit 10 moves by a terminal operation such as a tablet, the cartography mode can be started by establishing communication between the mobile unit 10 and the terminal.

  Next, in step S102, the control circuit 105 resets the value (encoder value) of each rotary encoder to zero. In the subsequent step S103, the control circuit 105 determines whether the moving object 10 is in a turning operation. Whether or not the turning operation is in progress can be determined by whether or not a deviation greater than or equal to a predetermined value has occurred in each encoder value. If this determination is No, the process proceeds to step S104, where the control circuit 105 determines whether the encoder value has exceeded a threshold (e.g. 25 mm). If this determination is No, the process returns to step S103. If this determination is Yes, the process proceeds to step S106, the control circuit 105 adds a valid flag to the scan data immediately after, and stores the same in a dedicated folder for map creation.

  If the determination result in step S103 is Yes, the process proceeds to step S105, where the control circuit 105 determines whether a predetermined time (eg, 25 ms) has elapsed since the previous storage of scan data. If the determination result is No, step S105 is executed again. If the determination result is "Yes", the process proceeds to step S106, a valid flag is added to the scan data immediately after that, and the scan data is stored in a dedicated folder. After step S106, the process returns to step S102, and the above-described process is repeated.

  Although omitted in FIG. 5, scan data to which a valid flag is not attached may also be recorded in the storage device 107. The scan data that is not flagged as valid can be recorded with a cycle that is the same as or longer than the scan cycle of the laser range finder.

  After acquiring all scan data, the control circuit 105 starts an operation for creating a map. At the start of the operation, the scan data of the dedicated folder to which the valid flag is attached is referred to, and the operation for creating the map is performed.

  Hereinafter, the embodiment of the present disclosure will be described on the assumption that the mobile unit is an unmanned carrier. In this specification, an unmanned carrier may be described as "AGV" using abbreviations. The AGV is also denoted by "10" and denoted as AGV10. The following description can be similarly applied to mobile bodies other than AGVs, for example, mobile robots, drone, or manned vehicles, as long as no contradiction arises.

(1) Basic Configuration of System FIG. 6 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 apparatus 50 that manages the operation of the AGV 10. The terminal device 20 operated by the user 1 is also described in FIG.

  The AGV 10 is an unmanned transport carriage capable of "guideless" traveling, which does not require a derivative such as a magnetic tape for traveling. The AGV 10 can perform self-position estimation, and can transmit the result of estimation to the terminal device 20 and the operation management device 50. The AGV 10 can automatically travel in the moving space S in accordance with a command from the operation management device 50. The AGV 10 can also operate in a "tracking mode" that moves following a person or other mobile.

  The operation management device 50 is a computer system that tracks the position of each AGV 10 and manages traveling of each AGV 10. The operation management device 50 may be a desktop PC, a laptop PC, and / or a server computer. The operation management apparatus 50 communicates with each AGV 10 via the plurality of access points 2. For example, the operation management device 50 transmits, to each AGV 10, data of coordinates of a position to which each AGV 10 should go next. Each AGV 10 periodically transmits data indicating its position and orientation to the operation management device 50, for example, every 100 milliseconds. When the AGV 10 reaches the designated position, the operation management device 50 transmits data of coordinates of a position to be further advanced. The AGV 10 can also travel in the moving space S in accordance with the operation of the user 1 input to the terminal device 20. An example of the terminal device 20 is a tablet computer. Typically, travel of the AGV 10 using the terminal device 20 is performed at the time of map creation, and travel of the AGV 10 using the operation management device 50 is performed after the map creation.

  FIG. 7 shows an example of a moving space S in which three AGVs 10a, 10b and 10c exist. All AGVs are assumed to travel in the depth direction in the figure. The AGVs 10a and 10b are carrying the load placed on the top plate. The AGV 10 c runs following the front AGV 10 b. In addition, although the reference numerals 10a, 10b, and 10c are attached in FIG. 7 for convenience of description, it describes as "AGV10" below.

  The AGV 10 can also transfer a load using a tow truck connected to itself, in addition to the method of transferring the load placed on the top plate. FIG. 8A shows the AGV 10 and the tow truck 5 before being connected. Each leg of the tow truck 5 is provided with a caster. The AGV 10 is mechanically connected to the tow truck 5. FIG. 8B shows the connected AGV 10 and tow truck 5. When the AGV 10 travels, the tow truck 5 is pulled by the AGV 10. By pulling the tow truck 5, the AGV 10 can transport the load placed on the tow truck 5.

  The connection method of AGV10 and the pulling truck 5 is arbitrary. Here, an example will be described. A plate 6 is fixed to the top plate of the AGV 10. The tow truck 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 of the guide 7. When the insertion is completed, the AGV 10 penetrates the plate 6 and the guide 7 with an electromagnetic lock type pin (not shown) to lock the electromagnetic lock. Thereby, AGV10 and the pulling truck 5 are physically connected.

  Refer again to FIG. Each AGV 10 and the terminal device 20 can be connected, for example, on a one-to-one basis to perform communication conforming to the Bluetooth (registered trademark) standard. Each AGV 10 and the terminal device 20 can also perform communication compliant with Wi-Fi (registered trademark) using one or more access points 2. The plurality of access points 2 are connected to one another via, for example, a switching hub 3. Two access points 2a, 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 2 a, transferred to the access point 2 b via the switching hub 3, and transmitted from the access point 2 b to the terminal device 20. The data transmitted by the terminal device 20 is received by the access point 2 b, transferred to the access point 2 a via the switching hub 3, and transmitted from the access point 2 a to the AGV 10. Thereby, bi-directional communication between the AGV 10 and the terminal device 20 is realized. The plurality of access points 2 are also connected to the operation management device 50 via the switching hub 3. Thereby, bidirectional communication is realized also between the operation management device 50 and each of the AGVs 10.

(2) Creation of Environment Map In order to allow the AGV 10 to travel while estimating its own position, a map in the moving space S is created. The AGV 10 is equipped with a position estimation device and a laser range finder, and a map can be created using the output of the laser range finder.

  The AGV 10 transitions to the data acquisition mode by the operation of the user. In the data acquisition mode, the AGV 10 starts acquiring sensor data using a laser range finder. The laser range finder periodically scans the surrounding space S by emitting a laser beam of, for example, infrared or visible light around. The laser beam is reflected by, for example, a surface such as a wall, a structure such as a pillar, or an object 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 data indicating the position of each reflection point. The direction of arrival of reflected light and the distance are reflected in the position of each reflection point. Data of measurement results may be referred to as "measurement data" or "sensor data".

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

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

  The AGV 10 may create the map instead of the external device. The processing performed by the signal processing processor of the external device described above may be performed by a circuit such as a microcontroller unit (microcomputer) of the AGV 10. When creating a map within the AGV 10, there is no need to transmit the accumulated sensor data to an external device. The data capacity of sensor data is generally considered to be large. Since it is not necessary to transmit sensor data to an external device, occupation of the communication line can be avoided.

  In addition, the movement in the movement space S for acquiring sensor data can be implement | achieved when AGV10 drive | works according to a user's operation. For example, the AGV 10 wirelessly receives a traveling instruction instructing movement in each of the front, rear, left, and right directions from the user via the terminal device 20. The AGV 10 travels back and forth and left and right in the moving space S in accordance with a travel command to create a map. When the AGV 10 is connected to a steering apparatus such as a joystick by wire, the map may be created by traveling in the moving space S in the front, rear, left, and right according to a control signal from the steering apparatus. The sensor data may be acquired by a person pushing on the measurement cart on which the laser range finder is mounted.

  Although a plurality of AGVs 10 are shown in FIGS. 6 and 7, one AGV may be provided. When there are a plurality of AGVs 10, the user 1 can use the terminal device 20 to select one AGV 10 out of 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. The description of the process of estimating the self position will be described later.

(3) Configuration of AGV FIG. 9 is an external view of an exemplary AGV 10 according to the present embodiment. The AGV 10 has two drive wheels 11a and 11b, four casters 11c, 11d, 11e and 11f, a frame 12, a transport table 13, a travel control device 14, and a laser range finder 15. The two drive wheels 11a and 11b are provided on the right and left sides of the AGV 10, respectively. Four casters 11 c, 11 d, 11 e and 11 f are disposed at the four corners of the AGV 10. The AGV 10 also has a plurality of motors connected to the two drive wheels 11a and 11b, but the plurality of motors are not shown in FIG. Further, FIG. 9 shows one drive wheel 11a and two casters 11c and 11e located on the right side of the AGV 10 and a caster 11f located on the left rear, but the left drive wheel 11b and the left front The caster 11 d is not shown because it is hidden by the frame 12. The four casters 11c, 11d, 11e and 11f can freely pivot. In the following description, the drive wheel 11a and the drive wheel 11b are also referred to as a wheel 11a and a wheel 11b, respectively.

  The AGV 10 further includes at least one obstacle sensor 19 for detecting an obstacle. In the example of FIG. 9, four obstacle sensors 19 are provided at four corners of the frame 12. The number and arrangement of obstacle sensors 19 may be different from the example of FIG. The obstacle sensor 19 may be, for example, an apparatus capable of distance measurement, such as an infrared sensor, an ultrasonic sensor, or a stereo camera. In the case where the obstacle sensor 19 is an infrared sensor, for example, an infrared ray is emitted at regular time intervals, and an obstacle existing within a certain distance is detected by measuring a time until a reflected infrared ray returns. Can. When the AGV 10 detects an obstacle on the path based on a signal output from at least one obstacle sensor 19, the AGV 10 operates 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), an electronic component, and a substrate on which the components are mounted. The traveling control device 14 performs transmission and reception of data with the terminal device 20 described above and pre-processing calculation.

  The laser range finder 15 is an optical device that measures the distance to the reflection point by emitting a laser beam 15a of infrared or visible light, for example, and detecting the reflected light of the laser beam 15a. In the present embodiment, the laser range finder 15 of the AGV 10 is, for example, a pulsed laser beam while changing the direction every 0.25 degree in a space within a range of 135 degrees (270 degrees in total) with reference to the front of the AGV 10 The light 15a is emitted, and the reflected light of each laser beam 15a is detected. This makes it possible to obtain data of the distance to the reflection point in the direction determined by the angle for a total of 1081 steps every 0.25 degrees. In the present embodiment, the scan 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 scan result of the laser range finder 15. The map may reflect the surrounding walls of the AGV, structures such as columns, and the placement of 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 mobile are called a pose. The position and orientation of the moving body in a two-dimensional plane are represented by position coordinates (x, y) in the XY orthogonal coordinate system and an angle θ with respect to the X axis. The position and posture of the AGV 10, that is, the pose (x, y, θ) may be hereinafter simply referred to as "position".

  The position of the reflection point viewed from the emission position of the laser beam 15a can be expressed using polar coordinates determined by the angle and the distance. In the present embodiment, the laser range finder 15 outputs sensor data represented by polar coordinates. However, the laser range finder 15 may convert the position expressed in polar coordinates into orthogonal coordinates and output it.

  The structure and the operating principle of the laser range finder are known, so a further detailed description will be omitted 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 surrounding space and acquiring sensor data. As another example of such an external sensor, an image sensor and an ultrasonic sensor can be considered.

  The traveling control device 14 can estimate the current position of itself by comparing the measurement result of the laser range finder 15 with the map data held by itself. In addition, the map data currently hold | maintained may be the map data which other AGV10 created.

  FIG. 10A shows a first hardware configuration example of the AGV 10. FIG. 10A also shows a specific configuration of the traveling control device 14.

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

  The traveling control device 14 includes 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 as a measurement result to the microcomputer 14a, the position estimation device 14e and / or the memory 14b.

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

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

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

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

  The storage device 14c stores map data M of the space S in which the vehicle travels and data (traveling route data) R of one or more traveling routes. The map data M is created by the AGV 10 operating in the mapping 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. In the present embodiment, the map data M and the traveling route data R are stored in the same storage device 14c, but may be stored in different storage devices.

  An example of the travel route data R will be described.

  When the terminal device 20 is a tablet computer, the AGV 10 receives traveling route data R indicating a traveling route from the tablet computer. The travel route data R at this time includes marker data indicating the positions of a plurality of markers. “Marker” indicates the passing position (passing 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 positional information of markers at one or more intermediate waypoints. When the travel route includes one or more intermediate via points, a route from the start marker to the end marker via the travel via points in order is defined as the travel route. The data of each marker may include, in addition to the coordinate data of the marker, data of the orientation (angle) and traveling speed of the AGV 10 until moving to the next marker. When the AGV 10 temporarily stops at each marker position and performs self-position estimation and notification to the terminal device 20, the data of each marker is an acceleration time required to accelerate to the traveling speed, and / or It may include data of deceleration time required to decelerate from the traveling speed to a stop at the position of the next marker.

  The operation management device 50 (for example, a PC and / or a server computer) rather than the terminal device 20 may control the movement of the AGV 10. In that case, the operation management apparatus 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 management device 50, coordinate data of a target position to be headed to next, or data of a distance to the target position and angle to be traveled as travel route data R indicating a travel route.

  The AGV 10 can travel along the stored travel path while estimating its own position using the created map and the sensor data output from 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 the Wi-Fi (registered trademark) standard. Both standards include wireless communication standards using frequencies in the 2.4 GHz band. For example, in the mode in which the AGV 10 is run 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 estimation processing of the self position when traveling. The position estimation device 14e creates a map of the moving space S based on the position and attitude of the AGV 10 and the scan result of the laser range finder. When traveling, the position estimation device 14e receives sensor data from the laser range finder 15, and reads out the map data M stored in the storage device 14c. By matching the local map data (sensor data) created from the scan result of the laser range finder 15 with the map data M in a wider range, the self position (x, y, θ) on the map data M is obtained Identify The position estimation device 14 e generates “reliability” data indicating the degree to which the local map data matches the map data M. The data of the self position (x, y, θ) and the reliability 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 each data of the self position (x, y, θ) and the reliability and can display it on a built-in or connected display device.

  In this embodiment, although the microcomputer 14a and the position estimation device 14e are separate components, this is an example. It may be 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. FIG. 10A shows a chip circuit 14g including the microcomputer 14a and the position estimation device 14e. Hereinafter, an example in which the microcomputer 14a and the position estimation device 14e are provided separately and independently will be described.

  Two motors 16a and 16b are attached to two wheels 11a and 11b, respectively, to rotate each wheel. That is, the two wheels 11a and 11b are respectively drive wheels. In the present specification, the motor 16a and the motor 16b are described as being motors for driving the right and left wheels of the AGV 10, respectively.

  The moving body 10 further includes an encoder unit 18 that measures the rotational position or rotational speed 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 the rotation at any position of the power transmission mechanism from the motor 16a to the wheel 11a. The second rotary encoder 18 b measures the rotation at any position of the power transmission mechanism from the motor 16 b to the wheel 11 b. The encoder unit 18 transmits the signals acquired by the rotary encoders 18a and 18b to the microcomputer 14a. The microcomputer 14 a may control the movement of the mobile unit 10 using not only the signal received from the position estimation device 14 e but also the signal received from the encoder unit 18.

  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 to each motor by the PWM signal transmitted from the microcomputer 14a or the microcomputer in the motor drive circuit 17a, thereby adjusting the voltage applied to the motor.

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

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

  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 other than that described above with reference to FIG. 10B is the same as the configuration of FIG. 10A. Therefore, the description of the common configuration is omitted.

  The AGV 10 in the embodiment of the present disclosure may include a safety sensor such as a bumper switch not shown. The AGV 10 may include an inertial measurement device such as a gyro sensor. By using measurement data from an internal sensor such as the rotary encoders 18a and 18b or an inertial measurement device, it is possible to estimate the amount of change (angle) of the movement distance and posture of the AGV 10. These distance and angle estimates may be referred to as odometry data, and may perform a function of assisting the position and orientation information obtained by the position estimation device 14e.

(4) Map Data FIGS. 11A to 11F schematically show the AGV 10 moving while acquiring sensor data. The user 1 may move the AGV 10 manually while operating the terminal device 20. Alternatively, the unit provided with the travel control device 14 shown in FIG. 10A and FIG. 10B, or the AGV 10 itself may be mounted on a carriage, and sensor data may be acquired by the user 1 manually pushing or holding the carriage. .

  FIG. 11A shows an AGV 10 that scans the surrounding space using a laser range finder 15. A laser beam is emitted for each predetermined step angle and scanning is performed. 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. 11A to 11F, the position of the reflection point of the laser beam is schematically shown using a plurality of black points 4 represented by a symbol “·”. The scanning of the laser beam is performed at short intervals while the position and attitude of the laser range finder 15 change. Therefore, the number of actual reflection points is much larger than the number of reflection points 4 shown. The position estimation device 14e stores, for example, in the memory 14b, the position of the black point 4 obtained as the vehicle travels. The map data is gradually completed as the AGV 10 continues to scan while traveling. In FIGS. 11B-11E, only the scan range is shown for simplicity. The scan range is an example, and is different from the above-described example of 270 degrees in total.

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

  FIG. 11F schematically shows a part of the completed map 40. In the map shown in FIG. 11F, a free space is partitioned by a point cloud (Point Cloud) corresponding to a collection of reflection points of the laser beam. Another example of the map is an occupied grid map that distinguishes space occupied by an object from free space in grid units. The position estimation device 14e stores map data (map data M) in the memory 14b or the storage device 14c. The illustrated number or density of black spots is an example. In the present embodiment, when creating a map, the method described with reference to FIGS. 1 to 5 is used. Therefore, the map can be created faster than before.

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

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

  When the area where the AGV 10 travels is wide, the amount of data of the map data M increases. As a result, the time required to create a map may increase, and the self-location estimation may take a long time. If such a problem occurs, the map data M may be created and recorded as data of a plurality of partial maps.

  FIG. 12 shows an example in which the entire area of one floor of one factory is covered by a combination of four partial map data M1, M2, M3 and M4. In this example, one partial map data covers an area of 50 m × 50 m. A rectangular overlapping area of 5 m in width is provided at the boundary between two adjacent maps in each of the X direction and the Y direction. This overlapping area is called "map switching area". When the AGV 10 traveling while referring to one partial map reaches the map switching area, it switches to a traveling referring to another adjacent partial map. The number of partial maps is not limited to four, and may be appropriately set according to the area of the floor on which the AGV 10 travels, and the performance of a computer that executes map creation and self-position estimation. The size of the partial map data and the width of the overlapping area are not limited to the above example, and may be set arbitrarily.

(5) Configuration Example of Operation Management Device FIG. 13 shows a hardware configuration example of the operation management device 50. The operation management apparatus 50 includes 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, the memory 52, the position DB 53, the communication circuit 54, the map DB 55, and the 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. Typically, the CPU 51 is a semiconductor integrated circuit.

  The memory 52 is a volatile storage device that stores a computer program that the CPU 51 executes. The memory 52 can also be used as a work memory when the CPU 51 performs an operation.

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

  The communication circuit 54 performs wired communication conforming to, for example, the Ethernet (registered trademark) standard. The communication circuit 54 is connected to the access point 2 (FIG. 6) 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 data of an internal map of a factory or the like on which the AGV 10 travels. The map may be the same as or different from the map 40 (FIG. 11F). The data format is not limited 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 represented by a hard disk or an optical recording medium represented by an optical disc.

  The image processing circuit 56 is a circuit that generates data of an image displayed on the monitor 58. The image processing circuit 56 operates only when the administrator operates the operation management device 50. In the present embodiment, particularly the detailed description is omitted. The monitor 59 may be integrated with the operation management device 50. Further, the CPU 51 may perform the processing of the image processing circuit 56.

(6) Operation of Operation Management Device The outline of the operation of the operation management device 50 will be described with reference to FIG. FIG. 14 is a view schematically showing an example of the movement route of the AGV 10 determined by the operation management device 50. As shown in FIG.

The outline of the operation 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 M ₁ and travels through several positions to the final destination position M _{n + 1} (n: 1 or more positive integer) . In the position DB 53, coordinate data indicating positions 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 are recorded.

CPU51 of traffic control device 50 reads out the coordinate data of the position _{M 2} with reference to the position DB 53, and generates a travel command to direct the position _{M 2.} The communication circuit 54 transmits a traveling command to the AGV 10 via the access point 2.

The CPU 51 periodically receives data indicating the current position and attitude from the AGV 10 via the access point 2. Thus, the operation management device 50 can track the position of each AGV 10. CPU51 determines that the current position of the AGV10 matches the position _{M 2,} reads the coordinate data of the position _{M 3,} and transmits the AGV10 generates a travel command to direct the position _{M 3.} That is, when it is determined that the AGV 10 has reached a certain position, the operation management device 50 transmits a traveling command for directing to the next passing position. Thus, the AGV ₁₀ can reach the final target position _{Mn + 1} . The passing position and the target position of the AGV 10 described above may be referred to as a “marker”.

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

1 user 2a, 2b access point 10 AGV (mobile)
14 Driving Control Device 14a Microcomputer (Arithmetic Circuit)
14b Memory 14c Memory Device 14d Communication Circuit 14e Position Estimation Device 16a, 16b Motor 15 Laser Range Finder 17 Drive Device 17a, 17b Motor Drive Circuit 18 Encoder Unit 18a, 18b Rotary Encoder 19 Obstacle Sensor 20 Terminal Device (mobile such as tablet computer Computer)
50 operation control device 51 CPU
52 memory 53 location database (location DB)
54 communication circuit 55 map database (map DB)
56 image processing circuit 100 mobile object management system 101 external sensor 103 internal sensor 105 control circuit 107 storage device

Claims (10)

It is a mobile and
An external sensor that periodically scans the environment and outputs sensor data for each scan,
An internal sensor that detects the moving distance or moving speed of the moving body;
A control circuit connected to the external sensor and the internal sensor;
Storage device,
Equipped with
The control circuit is configured to use, as the data for map creation, sensor data by scanning selected from the sensor data output from the external sensor and the moving distance detected by the internal sensor or the moving speed. Store in storage device,
Moving body.   The control circuit stores both the sensor data from the selected scan and the sensor data from the non-selected scan in the storage device, and the sensor data from the selected scan is the data for map creation. The mobile according to claim 1, wherein a code indicating.   The control circuit stores sensor data of the selected scan in a first area of the storage device, and stores sensor data of a non-selected scan in a second area of the storage device. Mobile body described.   The mobile unit according to claim 1, wherein the control circuit stores sensor data of the selected scan in the storage device, and discards sensor data of a non-selected scan without storing the sensor data in the storage device.   The movement according to any one of claims 1 to 4, wherein when the mobile is moving, the number of scans selected by the control circuit per unit time is a monotonically increasing function of the moving speed of the mobile. body.   The mobile according to claim 5, wherein when the mobile is pivoting, the number of scans selected by the control circuit per unit time is a predetermined value exceeding 0.   The mobile unit according to any one of claims 1 to 6, wherein the control circuit stores sensor data by a scan selected every time the mobile unit moves by a predetermined distance in the storage device as the map creation data. The control circuit
When the moving body travels straight, sensor data by a scan selected every time the mobile object moves a fixed distance is stored in the storage device as the map creation data.
When the movable body is turning, sensor data by a scan selected every constant time is stored in the storage device as the map creation data.
The mobile according to any one of claims 1 to 7. Further equipped with multiple wheels,
The outside sensor is a laser range finder,
The internal sensor includes a plurality of rotary encoders that respectively detect rotations of the plurality of wheels.
The mobile according to any one of claims 1 to 8. The control circuit
Reading the mapping data from the storage device;
The mobile unit according to any one of claims 1 to 9, wherein the sensor data are linked to create an environmental map by matching the sensor data included in the map creation data.

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