Moving body and moving body control system

Abstract

A moving body (1) comprises: a driving device (51) that generates driving force for travel; scanners (12a, 12b) that optically scan a floor surface to generate a partial floor surface image; and a controller (54) that controls the driving device (51) to reduce any deviation between a prescribed path and the current position of the moving body (1), which is detected on the basis of the partial floor surface image, so that the moving body (1) travels on the path. The controller (54) causes the scanners (12a, 12b) to intermittently generate partial floor surface images at prescribed intervals.

Description

Mobile objects and mobile object control systems

[0001] The present invention relates to a mobile object and a mobile object control system.

[0002] One mobile device is equipped with a moving means for moving the device along the surface of a structure, a photographing means provided on the bottom of the device for photographing the surface of the structure, and an identification means for identifying the position of the device by comparing image data output from the photographing means with matching data for each position registered in advance (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2019-185465

[0004] However, when continuously photographing the floor to generate partial floor images, the amount of data that needs to be processed and transmitted for the partial floor images becomes large, which requires high performance from the system implemented in the mobile body, increasing the cost of the mobile body.

[0005] The present invention has been made in view of the above problems, and has as its object to provide a relatively low-cost mobile object and a mobile object control system for controlling such a mobile object.

[0006] The mobile body according to the present invention includes a drive device that generates a driving force for traveling, a scanner that optically scans a floor surface to generate a partial floor image, and a controller that controls the drive device so that the mobile body travels along a predetermined path by reducing the deviation between the current position of the mobile body detected based on the partial floor image and the predetermined path. The controller then causes the scanner to generate the partial floor image intermittently at predetermined intervals.

[0007] The mobile object control system according to the present invention comprises a plurality of mobile objects traveling along a route in a predetermined area of ​​a floor surface, and a management server. Each of the plurality of mobile objects (a) scans a portion of the floor surface at the current position of the mobile object to generate a partial floor image, and (b) transmits the partial floor image to the management server. The management server comprises a communication device that receives the partial floor images from the plurality of mobile objects, a mobile object position identification unit that identifies the current position of the mobile object based on the received partial floor image, and a mobile object control unit that controls the operation of each of the plurality of mobile objects based on the identified current position of the mobile object. Each of the plurality of mobile objects generates the partial floor image intermittently at a predetermined interval, and the mobile object control unit sets the interval for the mobile object.

[0008] According to the present invention, a relatively low-cost mobile object and a mobile object control system for controlling such a mobile object can be obtained.

[0009] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0010] FIG. 1 is a diagram showing the configuration of a mobile object control system according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a floor surface on which a mobile object 1 in FIG. 1 travels. FIG. 3 is a perspective view showing the mechanical configuration of the mobile object 1 in FIG. 1. FIG. 4 is a diagram illustrating an example of a scanner 12a in the mobile object 1 shown in FIG. 3. FIG. 5 is a diagram illustrating another example of the scanner 12a in the mobile object 1 shown in FIG. 3. FIG. 6 is a block diagram showing the electrical configuration of the mobile object 1 in FIG. 1. FIG. 7 is a diagram illustrating the intermittent shooting operation of the mobile object 1 in FIG. 1. FIG. 8 is a block diagram showing the configuration of a management server 2 in FIG. 1. FIG. 9 is a flowchart illustrating the operation of the management server 2 in FIG. 1.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] Embodiment 1.

[0013] Fig. 1 is a diagram showing the configuration of a mobile object control system according to an embodiment of the present invention. Fig. 2 is a diagram illustrating a floor surface on which a mobile object 1 in Fig. 1 travels. As shown in Fig. 1, the mobile object control system includes a plurality of mobile objects 1 traveling along respective routes in a predetermined area on the floor surface, and a management server 2.

[0014] Each mobile object 1 is a self-propelled mobile object, such as an automatic guided vehicle (AGV) or an autonomous mobile robot (AMR). The mobile object 1 travels along a predetermined route on the floor surface 101 of a predetermined area while optically scanning the floor surface 101 at the current location of the mobile object 1. The mobile object control system does not require markers or the like to be physically installed on the floor surface 101 as a route. The management server 2 sets the route as data, searches for a location in a floor surface image of the floor surface 101 of the predetermined area that matches a partial floor surface image of the current location of the mobile object 1, identifies the actual current location of the mobile object 1 based on the matched location, and controls the operation of the mobile object 1 according to the set route and its current location.

[0015] Here, the floor surface 101 is, for example, the floor surface of a factory, warehouse, etc., and has scratches, dirt, etc. in addition to the original pattern 101a (i.e., the pattern of the surface of the floor material such as tile or concrete), so that the image pattern differs depending on the position in a high-resolution floor surface image of a predetermined area. Therefore, for example, by using pattern matching, image search using machine learning, etc., the current position of the moving object 1 can be uniquely identified.

[0016] Fig. 3 is a perspective view showing the mechanical configuration of the mobile unit 1 in Fig. 1. As shown in Fig. 3, the mobile unit 1 includes four casters 11 installed at the four corners of the bottom surface, scanners 12a and 12b, and a frame body 13 to which the casters 11 and scanners 12a and 12b are fixed.

[0017] The caster 11 has a driven wheel that contacts the floor surface 101 and is fixed to the frame body 13 so as to be rotatable in the horizontal direction.

[0018] Scanner 12a optically scans a portion of the floor surface 101 to generate a partial floor surface image (first partial floor surface image). Scanner 12a is arranged at the tip of the moving body 1 in the traveling direction. Scanner 12b optically scans a portion of the floor surface 101 to generate a partial floor surface image (second partial floor surface image). Scanner 12b is arranged at the rear end of the moving body 1 in the traveling direction. Each of scanners 12a and 12b (a) is arranged on the bottom side of the moving body 1 facing the floor surface, and (b) repeatedly generates line images of a predetermined width perpendicular to the traveling direction of the moving body 1 as partial floor surface images. Scanners 12a and 12b scan the floor surface at a predetermined high resolution (for example, 600 dpi).

[0019] The frame body 13 is a body having a frame structure.

[0020] Furthermore, the mobile body 1 includes drive wheel units 21 a, 21 b, 21 c, and 21 d. Each drive wheel unit 21 a, 21 b, 21 c, and 21 d includes a drive wheel 31 that contacts the floor surface, a support portion 32 that rotatably supports the drive wheel 31, a wheel frame portion 33 to which the support portion 32 is fixed, a rotation support portion 34 that rotatably fixes one end of the wheel frame portion 33 to the frame body 13 (one of the beams 13 a, 13 b), and a spring member 35 that urges the other end of the wheel frame portion 33 against the frame body 13 (the other of the beams 13 a, 13 b). As a result, the restoring force of the spring member 35 presses the drive wheel 31 against the floor surface with a predetermined pressure.

[0021] Furthermore, each of the drive wheel units 21a, 21b, 21c, and 21d includes a drive device (not shown) that generates and transmits driving force for running to the drive wheels 31. The drive devices are installed independently for each of the drive wheel units 21a, 21b, 21c, and 21d, and individually generate and transmit driving force to the drive wheels 31. Here, the drive devices generate driving force using a motor and transmit the driving force to the drive wheels 31 using gears or the like. The drive wheels 31 include, for example, a drive shaft connected to the drive device, a hard wheel fixed to the drive shaft, and an elastic tire fitted on the outside of the wheel.

[0022] Fig. 4 is a diagram showing an example of the scanner 12a in the moving object 1 shown in Fig. 3. For example, as shown in Fig. 4, each of the scanners 12a and 12b includes a light-emitting unit (not shown) that irradiates the floor surface with light, an image sensor 41, and a reduction optical system 42 (one or more lenses) that focuses reflected light obtained when the light from the light-emitting unit is reflected by the floor surface onto the image sensor 41.

[0023] Fig. 5 is a diagram showing another example of the scanner 12a in the mobile object 1 shown in Fig. 3. Furthermore, for example, as shown in Fig. 5, the scanners 12a and 12b may be equipped with contact image sensors. In this case, the scanners 12a and 12b are scanners with a life-size optical system equipped with a line sensor 41a including a plurality of light-receiving elements and a lens array 42a.

[0024] Fig. 6 is a block diagram showing the electrical configuration of the moving body 1 in Fig. 1. As shown in Fig. 6, the moving body 1 includes a power supply unit 52, a communication unit 53, and a controller 54 in addition to the drive unit 51 described above.

[0025] The power supply device 52 includes a secondary battery 52a and a charging unit 52b for the secondary battery 52a, and supplies power to the drive device 51, the communication device 53, and the controller 54. When the mobile object 1 is placed in a charging pod (not shown) connected to a commercial power source, the charging unit 52b receives power from the charging pod by contact or contactless means and charges the secondary battery 52a with the received power.

[0026] The communication device 53 performs data communication with an external device (such as a server) via wireless communication in accordance with a predetermined communication protocol.

[0027] The controller 54 includes a computer and an ASIC (Application Specific Integrated Circuit), and performs data processing, control of the drive device 51, control of the communication device 53, etc. using the computer (software processing) and the ASIC (hardware processing).

[0028] In response to a request from the controller 54, the communication device 53 (a) transmits a partial floor image to the management server 2 and receives from the management server 2 the deviation between the current position of the moving body 1 and the route, or a control amount corresponding to the deviation, detected by the management server 2 based on the partial floor image. Then, based on the received deviation or control amount (control amount of each drive device 51), the controller 54 controls the drive devices 51 so that the moving body 1 travels on the above-mentioned route, or controls the drive devices 51 to stop the moving body 1.

[0029] The partial floor image is a band image composed of a predetermined number of line images. The scanners 12a and 12b repeatedly generate line images of a predetermined width perpendicular to the traveling direction of the mobile object 1, and an image conversion unit (not shown) buffers the line images and converts the predetermined number of line images into a partial floor image. This image conversion unit may be provided in the mobile object 1 (controller 54) or the management server 2.

[0030] In addition, either the first partial floor image or the second partial floor image may be used as the partial floor image, or the current position may be derived in the same manner for each of the first partial floor image and the second partial floor image.

[0031] Fig. 7 is a diagram illustrating the intermittent photographing operation of the moving body 1 in Fig. 1. For example, as shown in Fig. 7, the controller 54 causes the scanners 12a and 12b to repeatedly generate partial floor images 201 intermittently at a predetermined photographing interval (time or distance), and the communication device 53 immediately transmits the intermittently generated partial floor images 201 to the management server 2.

[0032] The photographing interval may be fixed or variable. For example, the photographing interval is derived by adding or subtracting a correction amount to or from a default photographing interval (e.g., the same length as the photographing length of one partial floor image).

[0033] For example, the photographing interval is adjusted according to the speed of the moving body 1. In other words, the photographing interval (time) is adjusted so that it becomes longer as the speed of the moving body 1 decreases.

[0034] Furthermore, for example, the photographing interval is adjusted according to the turning angle of the moving body 1. In other words, the photographing interval (time) is adjusted so that it becomes shorter as the turning angle of the moving body 1 (the angular change in the traveling direction of the moving body 1 when turning) increases.

[0035] In addition, the partial floor image (image data thereof) may be compressed in the mobile object 1 before being transmitted to the management server 2 , and the data may be expanded in the management server 2 .

[0036] If the rotational speed of the drive wheels 31 of the drive wheel units 21a and 21b and the rotational speed of the drive wheels 31 of the drive wheel units 21c and 21d are made the same, the mobile body 1 will move straight, but if the rotational speed of the drive wheels 31 of the drive wheel units 21a and 21b and the rotational speed of the drive wheels 31 of the drive wheel units 21c and 21d are made different from each other, the mobile body 1 will turn. Therefore, the drive devices 51 of each drive wheel unit 21a, 21b, 21c, and 21d are controlled to reduce the above-mentioned deviation.

[0037] Furthermore, the inclination of the traveling direction with respect to the route may be derived based on the deviation obtained from the first partial floor image and the deviation obtained from the second partial floor image.

[0038] FIG. 8 is a block diagram showing the configuration of the management server 2 in FIG.

[0039] The management server 2 in FIG. 1 includes a communication device 61 , a processing device 62 , and a storage device 63 .

[0040] The communication device 61 communicates data with the mobile object 1 via a predetermined communication path 3 (a wireless communication path and / or a wired communication path). For example, the communication device 61 is a wireless network interface, a data communication interface for a mobile phone network, a short-range wireless communication interface, etc. Alternatively, the communication path 3 may include a wireless station, and the communication device 61 may be connected to the wireless station via a wired communication path and the mobile object 1 may be connected to the wireless station via a wireless communication path, thereby enabling the communication device 61 to communicate data with the mobile object 1.

[0041] The communication device 61 performs data communication with a plurality of mobile bodies 1 and receives the above-mentioned transmission data from the plurality of mobile bodies 1 .

[0042] The arithmetic processing device 62 is a computer equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and operates as various processing units by loading programs from the ROM or storage device 63 into the RAM and executing them on the CPU. Here, the arithmetic processing device 62 operates as a route setting unit 71, a mobile object position specifying unit 72, a mobile object control unit 73, and a floor image updating unit 74.

[0043] The storage device 63 is a non-volatile storage device that stores programs and data. Here, the storage device 63 stores floor surface data 63a in advance.

[0044] The floor data 63a includes image data of the floor image of the entire floor surface of the above-mentioned specified area, and position data indicating the correspondence between the position (pixel position) in the floor image and the actual position on the floor. This image data identifies the position of the partial floor image in the floor image (i.e., the position of the part in the floor image that is closest to the partial floor image), and this position data converts the position of the partial floor image in the floor image into a position on the actual floor.

[0045] The path setting unit 71 sets a path for the mobile object 1 as path data within a predetermined area on the floor surface 101. For example, the path is made up of one or more links, and the path data includes coordinate values ​​of the start point and end point of each link. For example, the path setting unit 71 may be connected to a manufacturing execution system (MES) and set a path for the mobile object 1 according to an operation of the mobile object 1 (such as transporting parts, etc.) requested by the manufacturing execution system.

[0046] The moving object position identifying unit 72 identifies the current position of the moving object 1 traveling along a route in a predetermined area on the floor surface 101. Specifically, the moving object position identifying unit 72 (a) acquires a partial floor image indicated by the transmission data received from each moving object 1 while traveling, (b) identifies the position of the partial floor image in the floor surface image of the entire predetermined area, and (c) identifies the current position of the moving object 1 (actual position on the floor surface 101) based on the identified position. Here, the partial floor image is generated by scanning a portion of the floor surface 101 opposite the bottom surface of the moving object 1 with scanners 12a and 12b arranged on the bottom side of the moving object 1. Note that the current position of the moving object 1 is expressed, for example, by a physical distance from a predetermined reference position on the floor surface 101. Furthermore, the position of the partial floor image in the floor surface image of the entire predetermined area is expressed by a pixel position in the floor surface image of the entire predetermined area, and the correspondence between the current position of the moving object 1 and the position of this partial floor image is known.

[0047] Furthermore, the moving object position specifying unit 72 acquires partial floor images using the communication device 61. The floor images and partial floor images may be color image data generated by the color scanners 12a and 12b, or may be grayscale image data generated by the monochrome scanners 12a and 12b.

[0048] Furthermore, the moving object position identifying unit 72 identifies the position of the partial floor image in the floor image of the entire predetermined area, for example, by image search using pattern matching or machine learning. At this time, even if a part of the floor image of the entire predetermined area does not completely match the partial floor image, the position with the highest probability in the floor image of the entire predetermined area is identified as the position of the partial floor image.

[0049] The mobile object control unit 73 controls the operation of the mobile object 1 based on the identified current position of each mobile object 1. The mobile object control unit 73 controls the operation of the mobile object 1 by transmitting, to the mobile object, an operation command based on the identified current position of the mobile object 1 using the communication device 61.

[0050] Specifically, the mobile body control unit 73 (a) identifies the deviation between the route set by the route setting unit 71 and the current position of the mobile body 1, and causes the mobile body 1 to travel so as to reduce the deviation (for example, by turning the mobile body 1 in accordance with the deviation), and (b) stops the mobile body 1 if the identified current position is a stopping position.

[0051] The floor image update unit 74 updates the portion of the partial floor image identified in the floor image of the entire predetermined area with the acquired partial floor image. As a result, even if there is a change in the floor surface 101 (change over time, adhesion of dirt, etc.), the portion of the floor image of the entire predetermined area through which the moving object 1 has passed is updated to the most recent floor image, thereby suppressing errors in detecting the current position in the moving object position identification unit 72.

[0052] Furthermore, the mobile body control unit 73 transmits an image capturing interval together with an operation command to each mobile body 1, and sets the image capturing interval in the mobile body 1.

[0053] In this case, the mobile body control unit 73 sets the shooting interval and the timing of generating partial floor images for each of the multiple mobile bodies 1 so that the timing of generating partial floor images for the multiple mobile bodies 1 is uniform (i.e., so that the number of mobile bodies 1 whose timing of generating partial floor images is included in a specified unit time is approximately constant).

[0054] The moving body control unit 73 may also set a photographing interval corresponding to the current position of the moving body 1 for the moving body 1. In this case, a photographing interval (time or distance) corresponding to each position on the floor surface is set in advance in the floor surface data 63a, and the moving body control unit 73 refers to the floor surface data 63a to identify a photographing interval corresponding to the current position of the moving body 1 and sets the photographing interval for the moving body 1.

[0055] Next, the operation of the mobile object control system will be described with reference to a flowchart of FIG.

[0056] The route setting unit 71 of the management server 2 sets a route for the mobile object 1 in accordance with a user operation or the like (step S1). For example, route data indicating the route is stored in advance in the storage device 63, and the route setting unit 71 reads out the route data and sets it as the route for the mobile object 1.

[0057] Thereafter, the mobile object control unit 73 uses the communication device 61 to transmit an operation command to the mobile object 1 to cause the mobile object 1 to start traveling. In the mobile object 1, the controller 54 uses the communication device 53 to receive the operation command and controls the drive device 51 to cause the mobile object 1 to start traveling. At that time, the mobile object 1 captures partial floor surface images at a default shooting interval.

[0058] In the management server 2, when the mobile object position identification unit 72 receives a line image or a partial floor image using the communication device 61 (step S2), it searches for the partial floor image in the overall floor image by pattern matching or the like, identifies the position of the partial floor image in the overall floor image, and identifies the actual current position of the mobile object 1 corresponding to that position (step S3). When a line image is received, a predetermined number of line images are buffered and used as the partial floor image. When the position of the partial floor image in the overall floor image is identified, the floor image update unit 74 updates the corresponding part of the overall floor image in the floor data 63a with the received partial floor image (step S4).

[0059] Then, the mobile object control unit 73 determines whether the identified current position is a stop position (step S5). If the identified current position is not a stop position, the mobile object control unit 73 identifies the deviation between the above-mentioned path and the current position of the mobile object 1 (step S6), and transmits the deviation amount or the corresponding control amount of the mobile object 1 as an operation command to the mobile object 1 so as to reduce the deviation (step S7). At this time, the mobile object control unit 73 also transmits the shooting interval to the mobile object 1. Thereafter, the process returns to step S2, and the processes from step S3 onwards are executed for the next partial floor image. Note that if there is no deviation, the mobile object control unit 73 does not transmit an operation command and causes the mobile object 1 to maintain traveling in the current direction and speed.

[0060] In each moving body 1, (a) upon receiving an operation command and a photographing interval, the moving body 1 controls the drive device 51 in accordance with the operation command to adjust the traveling of the moving body 1 (for example, by turning the moving body 1 to the right or left so as to move closer to the route), and (b) while traveling, the scanners 12a and 12b are operated at the photographing interval to intermittently and repeatedly acquire partial photographed images, which are then transmitted to the management server 2 using the communication device 53. Note that when a new photographing interval is received from the management server 2, the photographing interval is updated to the received photographing interval.

[0061] On the other hand, if the identified current position is a stop position, the mobile object control unit 73 uses the communication device 61 to transmit a stop command to the mobile object 1 (step S8). Then, the mobile object control unit 73 determines whether the identified current position (or this stop position) is the end of the route (step S9), and if the identified current position (or this stop position) is the end of the route, ends the travel of the mobile object 1 on the route.

[0062] On the other hand, if the identified current position (or this stop position) is not the end of the route, the mobile object 1 resumes traveling on the route when a predetermined condition is met (such as completion of a predetermined operation by the mobile object 1 at that position or receipt of a command to resume traveling from the management server 2). Then, the process returns to step S2, and the processing from step S3 onwards is executed for the next partial floor image.

[0063] As described above, according to the first embodiment, the mobile object 1 includes the drive device 51 that generates a driving force for traveling, the scanners 12a and 12b that optically scan the floor surface to generate a partial floor image, and the controller 54 that controls the drive device 51 so that the mobile object 1 travels along a predetermined path by reducing the deviation between the current position of the mobile object 1 detected based on the partial floor image and the predetermined path. The controller 54 causes the scanners 12a and 12b to generate partial floor images intermittently at predetermined intervals.

[0064] This reduces the amount of data to be processed and transmitted for the partial floor image, and the processing speed of the system implemented in the mobile body can be relatively low, so the cost of the mobile body 1 can be relatively low.

[0065] Embodiment 2.

[0066] In the second embodiment, the management server 2 is not provided, and the mobile body 1 includes a storage device 63 (floor surface data 63a), a route setting unit 71, a mobile body position identification unit 72, a mobile body control unit 73, and a floor surface image update unit 74. In other words, without using the above-mentioned management server 2, the mobile body 1 stores a floor surface image of the entire floor surface 101 (i.e., the range of movement of the mobile body 1), and similarly identifies the position of a partial floor surface image in the floor surface image, identifies the actual current position corresponding to that position, and autonomously controls running and stopping.

[0067] The other configurations and operations of the moving body 1 according to the second embodiment are the same as those of the first embodiment, and therefore the description thereof will be omitted.

[0068] It should be noted that various changes and modifications to the above-described embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing its intended advantages. In other words, it is intended that such changes and modifications be included within the scope of the claims.

[0069] For example, in the above embodiment, the moving body 1 does not need to be provided with the scanner 12b.

[0070] The present invention is applicable to, for example, AGVs.

Claims

1. A moving body comprising: a drive device that generates a driving force for traveling; a scanner that optically scans a floor surface to generate a partial floor image; and a controller that controls the drive device so that the moving body travels along a predetermined path by reducing the deviation between the current position of the moving body detected based on the partial floor image and the predetermined path, wherein the controller causes the scanner to generate the partial floor image intermittently at predetermined intervals.

2. A moving body according to claim 1, characterized in that said interval is adjusted according to the speed of said moving body.

3. A moving body according to claim 1, characterized in that said interval is adjusted according to the turning angle of said moving body.

4. A mobile object control system comprising: a plurality of moving objects running along a route in a specified area of ​​a floor; and a management server, wherein each of the plurality of moving objects (a) scans a portion of the floor at the current position of the moving object to generate a partial floor image, and (b) transmits the partial floor image to the management server, wherein the management server comprises a communication device that receives the partial floor images from the plurality of moving objects, a mobile object position identification unit that identifies the current position of the moving object based on the received partial floor image, and a mobile object control unit that controls the operation of each of the plurality of moving objects based on the identified current position of the moving object, wherein each of the plurality of moving objects intermittently generates the partial floor image at a specified interval, and the mobile object control unit sets the interval for the moving object.

5. The mobile body control system according to claim 4, characterized in that the mobile body control unit sets the interval and the timing of generating the partial floor image for the multiple moving bodies so that the timing of generating the partial floor image for the multiple moving bodies is uniform.

6. A mobile object control system according to claim 4, characterized in that said mobile object control unit sets said interval for said mobile object in accordance with the current position of said mobile object.

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