Automated guided vehicle, automated guided vehicle control method, and automated guided vehicle control program

Abstract

This technology provides a way to stably transport a single object when multiple automated guided vehicles (AGVs) are used to transport it. [Solution] The automated guided vehicle according to the embodiment includes a communication interface that receives a driving task which includes an instruction to transport an object using a plurality of automated guided vehicles, including the automated guided vehicle; and a processor that, based on the driving task, moves to the location where the object is placed, establishes a connection with other automated guided vehicles among the plurality of automated guided vehicles through the communication interface, controls a lifting device included in the automated guided vehicle to lift the object, measures the center of gravity of the object based on the measurement result of a pressure-sensitive element placed on the upper surface of the lifting device, calculates a control amount to control the operation of the plurality of automated guided vehicles based on the measured center of gravity, and controls the operation of the automated guided vehicles so that the center of gravity of the object does not shift while moving to the destination according to the driving task.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to an automated guided vehicle, an automated guided vehicle control method, and an automated guided vehicle control program. [Background Art]

[0002] In recent years, the handling volume of various commodities (hereinafter referred to as articles) has increased in warehouses such as logistics delivery bases, and automation of article processing has been promoted to reduce the work burden on workers. For example, in accordance with instructions from a host device, various automatic devices cooperate with each other, and conveyed objects such as shelves that store articles are conveyed by automated guided vehicles or the like.

[0003] Generally, automated guided vehicles are designed and used to convey one conveyed object. However, when the conveyed object is a long object, the long conveyed object is loaded by a plurality of automated guided vehicles, and conveyed by linking the travel control of each automated guided vehicle. When a plurality of automated guided vehicles are used to convey one conveyed object, control of each automated guided vehicle becomes complicated. For example, Patent Document 1 discloses a technique capable of correcting positional deviation by adjusting the rotation and travel angle of wheels based on the relative positional deviation between automated guided vehicles when conveying a long conveyed object by front and rear automated guided vehicles. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 2024-128352 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] In Patent Document 1, only the positional deviation between automated guided vehicles is considered, and the center of gravity of the conveyed object is not considered. For example, when the conveyed object becomes large or the position of the center of gravity is deviated, there is a problem that the position of the center of gravity during conveyance is not stable, and there is a risk of the conveyed object falling.

[0006] This invention was made in view of the above circumstances, and its purpose is to provide a technology for stably transporting an object when transporting a single object using multiple automated guided vehicles. [Means for solving the problem]

[0007] The automated guided vehicle according to the embodiment includes a communication interface that receives a driving task which includes an instruction to transport an object using a plurality of automated guided vehicles, including the aforementioned automated guided vehicle; and a processor that, based on the driving task, moves to the location where the object is placed, establishes a connection with other automated guided vehicles among the plurality of automated guided vehicles through the communication interface, controls a lifting device included in the automated guided vehicle to lift the object, measures the center of gravity of the object based on the measurement result of a pressure-sensitive element placed on the upper surface of the lifting device, calculates a control amount to control the operation of the plurality of automated guided vehicles based on the measured center of gravity, and controls the operation of the automated guided vehicles so that the center of gravity of the object does not shift while moving to the destination according to the driving task. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a conceptual diagram showing an example of a logistics system according to the embodiment. [Figure 2] Figure 2 shows an example of the configuration of an automated guided vehicle in an embodiment. [Figure 3] Figure 3 shows an example of the external appearance and cross-sectional view of an automated guided vehicle (AGV). [Figure 4] Figure 4 shows an example of the arrangement of pressure-sensitive elements and an example of the measurement intensity detected by the pressure-sensitive elements when the transported object is placed on the lifting device. [Figure 5] Figure 5 is a flowchart showing an example of the WCS's operation for generating driving tasks according to the embodiment. [Figure 6] Figure 6 is a flowchart showing an example of processing by multiple automated guided vehicles when transporting an object according to the embodiment. [Figure 7] Figure 7 shows an example of how an automated guided vehicle (AGV) can change the direction of travel of an object being transported. [Modes for carrying out the invention]

[0009] The automated guided vehicle (AGV), AGV control method, and AGV control program will be described in detail below with reference to the drawings. In the following embodiments, parts with the same numbering perform the same operation, and therefore repeated explanations will be omitted. For example, when there are multiple identical or similar elements, a common code may be used to describe each element without distinction, or a sub-number may be used in addition to the common code to describe each element separately.

[0010] Furthermore, in the following explanation, the notation A or B means at least one of A or B, and A, B, or C means at least one of A, B, or C. In addition, the notation A and B also means at least one of A and B, and A, B, and C means at least one of A, B, and C.

[0011] [Embodiment] (composition) Figure 1 is a conceptual diagram showing an example of a warehouse system according to the embodiment. As shown in Figure 1, the warehouse system S comprises a Warehouse Management System (WMS) 1 and a warehouse processing system 2. For example, the warehouse system S is a system used in logistics warehouses and the like.

[0012] Warehouse processing system 2 is an example of an goods processing system and includes a warehouse execution system (WES) 3, a warehouse control system (WCS) 4, an automated guided vehicle (AGV) 5, transported goods 6, etc.

[0013] WMS1 and WES3 may be connected via a network, where the network is, for example, a LAN (local area network). WES3 and WCS4 may be connected via a network. Furthermore, WCS4 and the automated guided vehicle 5 may each be connected via a network. Here, WCS4 and the automated guided vehicle 5 may be connected to the network wirelessly. Also, the automated guided vehicles 5 may be able to connect to each other using short-range wireless technology.

[0014] WMS1 can be composed of one or more computers, i.e., a processor, memory, and interfaces. The processor can be a CPU (central processing unit), MPU (micro processing unit), or DSP (digital signal processor), etc. WMS1 receives an order list from the upper server and sends the order list to WES3. The order list may also be received during outbound operations, inbound operations, or inventory operations.

[0015] WES3 (server) can be configured with one or more general-purpose computers, i.e., a processor 301, memory 302, and interface 303, etc. The processor 301 is a CPU, MPU, or DSP, etc. Memory 302 stores the processor's operating program, etc. Interface 303 communicates with WMS1, WCS4, etc.

[0016] The processor 301 of WES3 implements various functions by executing programs stored in the memory 302. For example, when the interface 303 receives an order list from WMS1, the processor 301 acquires the order list. The processor 301 generates a conveyance work plan from the order list. The processor 301 transmits the generated conveyance work plan to WCS4 or the like via the interface 303. In addition, the interface 303 receives a processing result including a result processed based on the conveyance work plan from WCS4, and transmits the result to WMS1. Further, the processor 301 may update the inventory management database in the memory 302 according to the conveyance processing result.

[0017] It should be noted that any general method may be used as the method for creating the conveyance work plan based on the order list, and detailed description thereof is omitted here. The conveyance work plan includes information such as the destination position of the automated guided vehicle 5 (for example, the arrangement position of the conveyed article 6), the conveyance destination, and the like.

[0018] WCS4 can be configured by one or more general-purpose computers, and includes a processor 401, a memory 402, and an interface 403. The processor 401 is a CPU, MPU, DSP or the like. The processor 401 controls the automated guided vehicle 5 based on a program stored in the memory and a conveyance work plan transmitted from WES3. In addition, the memory 402 stores conveyed article information including information such as dimensions (width, height, depth) and weight of each conveyed article 6 arranged in the warehouse.

[0019] The automated guided vehicle 5 is a robot that conveys conveyed objects 6 under the control of WCS 4. For example, the automated guided vehicle is an AGV (Automated Guided Vehicle) or an AMR (Autonomous Mobile Robot), or the like. Further, it goes without saying that the automated guided vehicle may include a SLAM (Simultaneous Localization and Mapping) type AGV. The automated guided vehicle 5 operates based on a control signal (e.g., a travel task) from WCS 4 or the like. For example, the automated guided vehicle 5 travels toward a specified loading position based on a travel task received from WCS 4, and lifts the conveyed object 6 at the specified loading position. The automated guided vehicle 5 travels toward a specified unloading position and moves to the specified unloading position (e.g., a predetermined workstation). The automated guided vehicle 5 also returns the conveyed object 6 to the return position after the picking operation at the workstation is completed.

[0020] The conveyed object 6 may be a shelf or the like that can be conveyed by the automated guided vehicle 5. In one embodiment, the conveyed object 6 is an elongated conveyed object 6, and is conveyed by a plurality of automated guided vehicles 5. For example, when the conveyed object 6 is elongated, a picking instruction is an instruction to convey the conveyed object 6 instead of being conveyed to a plurality of automated guided vehicles 5. In this case, the plurality of automated guided vehicles 5 cooperate with each other to convey the elongated conveyed object 6 by the plurality of automated guided vehicles 5.

[0021] Figure 2 is a diagram showing an example of the configuration of the automated guided vehicle 5 in the embodiment. The automated guided vehicle 5 includes a processor 501, a ROM 502, a RAM 503, an auxiliary storage device 504, a communication interface 505, a sensor 506, a drive unit 507, a battery 508, a charging mechanism 509, tires 510, a lifting device 511, an inclined stage 512, and the like. Further, the lifting device 511 includes a pressure-sensitive element 5111, and the inclined stage 512 includes a rotation mechanism 5121 and a translation mechanism 5122.

[0022] The processor 501 has the function of controlling the operation of the entire automated guided vehicle 5. The processor 501 may also be equipped with an internal cache and various interfaces. The processor 501 performs various processes by executing programs that are pre-stored in the internal memory, ROM 502, or auxiliary storage device 504.

[0023] For example, processor 501 is a CPU. Processor 501 may also be implemented using hardware such as an LSI, ASIC, or FPGA.

[0024] The processor 501 performs calculations and control processes necessary for operations such as acceleration, deceleration, stopping, and changing direction. Based on control signals from the WCS4, the processor 501 generates drive signals and outputs them to each part by executing programs stored in the ROM 502, etc.

[0025] For example, WCS4 transmits a control signal to move the automated guided vehicle (AGV) 5 from its current position to a first position (the position where the transported object 6 is placed), and then from the first position to a second position (the loading / unloading position). WCS4 also transmits a control signal to move the AGV 5 from the second position back to the first position. The processor 501 of the AGV 5 outputs a drive signal to the drive unit 507 corresponding to the control signals transmitted from WCS4. As a result, the AGV 5 moves from its current position to the first position, from the first position to the second position, and then back to the first position.

[0026] Furthermore, WCS4 may simultaneously transmit control signals to move the automated guided vehicle (AGV) 5 from its current position to a first position, from the first position to a second position, and from the second position back to the first position. Alternatively, the control signals to move the AGV 5 to the first or second position may be transmitted in separate signals. For example, WCS4 may set at least one waypoint and divide the signal into a control signal to move the AGV 5 to the waypoint and a control signal to move the AGV 5 from the waypoint to the first or second position, and then transmit each control signal to the AGV 5.

[0027] ROM 502 is a non-temporary computer-readable storage medium that stores the above-mentioned program. ROM 502 also stores data and various settings used by the processor 501 in performing various processes.

[0028] RAM503 is memory used for reading and writing data. RAM503 is used as a so-called work area, where it stores data that the processor 501 will temporarily use when performing various processes.

[0029] The auxiliary storage device 504 is a non-temporary computer-readable storage medium and may store the above-mentioned program. The auxiliary storage device 504 also stores data used by the processor 501 in performing various processes, data generated by processing by the processor 501, or various setting values.

[0030] The communication interface 505 is an interface that sends and receives data with WCS4 and other devices via a wireless LAN access point or the like. For example, the communication interface 505 supports wireless LAN connectivity. Furthermore, the communication interface 505 includes an interface module that directly sends and receives data with other automated guided vehicles 5 using short-range wireless technology (e.g., Bluetooth®, ZigBee, UWB, etc.).

[0031] Sensor 506 consists of multiple reflection sensors. Each reflection sensor is mounted around the automated guided vehicle 5. Each reflection sensor emits a laser beam, detects the time it takes for the laser beam to reflect off an object and return, detects the distance to the object based on the detected time, and notifies the processor 501 of the detection signal. Sensor 506 may also include sensors capable of reading positional information from a 2D code placed on the floor.

[0032] The drive unit 507 is a motor, which rotates or stops based on a drive signal output from the processor 501. The motor's power is transmitted to the tires 510 and then to the steering mechanism. Power from this motor allows the automated guided vehicle 5 to move to its destination.

[0033] Furthermore, the processor 501, which operates as a self-position detection unit, detects the current position of the automated guided vehicle 5 using images captured by the sensor 506 and cameras. The processor 501 then transmits position information, including the detected position and direction of movement, to the WCS4.

[0034] The battery 508 supplies the necessary power to the drive unit 507 and other components. The charging mechanism 509 connects the charging station and the battery 508, and the battery 508 is charged by power supplied from the charging station or the like via the charging mechanism 509.

[0035] Next, the tires 510, the lifting device 511, and the inclined stage 512 connected to the drive unit 507 will be described in detail. Figure 3 shows an example of the external appearance and cross-sectional view of the automated guided vehicle 5. Figure 3(a) shows an example of the external appearance of the automated guided vehicle 5, and Figure 3(b) shows an example of a cross-sectional view of the automated guided vehicle 5.

[0036] As shown in Figure 3, tires 510 are attached to the side of the main body of the automated guided vehicle 5. Furthermore, an inclined stage 512 is placed inside the automated guided vehicle 5, and a lifting device 511 is placed on the inclined stage 512.

[0037] The lifting device 511 is a device that moves up and down by a drive unit 507, which is driven by a drive signal corresponding to the loading and unloading instruction for the transported object 6 included in the control signal of the processor 501. For example, when the automated guided vehicle 5 is inside the transported object 6, the drive unit 507 rotates its motor (forward rotation) based on the drive signal output from the processor 501. Power from this motor causes the lifting device 511 to rise, and the transported object 6 is lifted. After the automated guided vehicle 5 reaches its destination, the drive unit 507 rotates its motor (reverse rotation) based on the drive signal output from the processor 501. Power from this motor causes the lifting device 511 to descend, and the transported object 6 is lowered to the floor.

[0038] As shown in Figure 3, the pressure-sensitive element 5111 is positioned on the upper surface of the lifting device 511, that is, on the surface that holds the conveyed object 6. Figure 4 shows an example of the arrangement of the pressure-sensitive elements 5111 and an example of the measurement intensity sensed by the pressure-sensitive elements 5111 when the transported object 6 is placed on the lifting device 511. As shown in Figures 3(a) and 4(a), the pressure-sensitive elements 5111 are elements uniformly mounted on the upper surface of the lifting device 511. By uniformly arranging the pressure-sensitive elements 5111 on the upper surface of the lifting device 511, the pressure-sensitive elements 5111 can measure the weight of the transported object 6 in two dimensions. The pressure-sensitive elements 5111 can be any element capable of measuring the weight of the transported object 6. The pressure-sensitive elements 5111 output the measured intensity to the processor 501. The processor 501 calculates the center of gravity of the transported object 6 based on this measured intensity. For example, the processor 501 calculates the center of gravity of the transported object 6 by summing up the measured intensities.

[0039] Furthermore, if the transported object 6 is tilted, as shown in Figure 4(b), the measurement intensity of the pressure-sensitive element 5111 will be biased to one side, causing the center of gravity calculated by the processor 501 to shift to the side where the transported object 6 is tilted. Therefore, the processor 501 of the automated guided vehicle 5 can detect that the transported object 6 is tilted by the shift in the center of gravity.

[0040] The inclined stage 512 is a stage that controls the inclination of the lifting device 511, that is, the inclination of the conveyed object 6. The inclined stage 512 includes a rotating mechanism 5121 and a translation mechanism 5122. As shown in Figures 3 and 4, the rotating mechanism 5121 is located below the lifting device 511, and the translation mechanism 5122 is located below the rotating mechanism 5121.

[0041] The rotating mechanism 5121 is a two-axis rotating mechanism having a rotation axis in the direction of travel, i.e., the front of the automated guided vehicle 5, and in a direction perpendicular to the direction of travel. Alternatively, the rotating mechanism 5121 may be a one-axis rotating mechanism having a rotation axis in the direction of travel of the automated guided vehicle 5. The rotating mechanism 5121 is a mechanism for correcting the tilt of the lifting device 511 from the horizontal. The rotating mechanism 5121 can be any mechanism capable of correcting the tilt of the lifting device 511. For example, it can be a mechanism that allows the tilting stage 512 to tilt when the rotating mechanism 5121 is rotated by the drive unit 507 according to instructions from the processor 501.

[0042] The translation mechanism 5122 is a mechanism capable of moving the lifting device 511 in the horizontal direction. For example, the translation mechanism 5122 corrects the shift in the center of gravity of the conveyed object 6 held by the lifting device 511 by moving in the horizontal direction (e.g., the x and y directions). The translation mechanism 5122 can be any mechanism capable of correcting the horizontal movement of the lifting device 511. For example, the translation mechanism 5122 can be any mechanism capable of moving the lifting device 511 in the horizontal direction. For example, it can be any mechanism that allows the lifting device 511 to move by moving the translation mechanism 5122 in the horizontal direction by the drive unit 507 in accordance with the instructions of the processor 501.

[0043] Next, we will explain the functions that the WCS4's processor 401 enables.

[0044] The processor 401 has the function of receiving the transport work plan transmitted by WES3 via interface 403. The transport work plan is a plan generated by the WES3's processor 301 based on the order list. For example, the transport work plan includes information such as the location information of the transported object 6 to be transported by the automated guided vehicle 5, the destination of the transported object 6 (e.g., a workstation), the weight information of the items to be stored in the transported object 6 during the receiving operation, and the destination after the receiving operation (storage node location).

[0045] The processor 401 has the function of comparing the transport information stored in the memory 402 with the transport work plan. For example, the processor 401 extracts information about the transport 6 included in the transport work plan. Then, the processor 401 refers to the extracted information and the transport information stored in the memory 402 to identify the dimensions (width, length, height) of the transport 6 to be used in the transport work plan.

[0046] The processor 401 has a function to determine whether multiple automated guided vehicles (AGVs) 5 are needed to transport the object 6. The processor 401 determines whether the dimensions of the identified object 6 exceed a predetermined length. For example, if it determines that the width or length of the object 6 exceeds a predetermined length, the processor 401 determines that multiple AGVs 5 are needed. On the other hand, if it determines that the width or length is less than a predetermined length, the processor 401 determines that the object 6 can be transported by a single AGV 5.

[0047] The processor 401 has the function of transmitting a travel task to one automated guided vehicle (AGV) 5. For example, if it is determined that the transported object 6 can be transported by one AGV 5, the processor 401 generates a travel task for one AGV 5 and transmits the travel task to the AGV 5 through the interface 403.

[0048] The processor 401 has a function to determine the number of automated guided vehicles (AGVs) 5 needed to transport the transported object 6. If it determines that multiple AGVs 5 are needed, the processor 401 determines the required number according to the dimensions. For example, if it determines that either the width or the length exceeds a predetermined length, the processor 401 determines that two AGVs 5 are needed to transport the transported object 6.

[0049] The processor 401 has the function of transmitting travel tasks to multiple automated guided vehicles (AGVs) 5. The processor 401 generates a travel task for each of the multiple AGVs 5 that will transport the transported object 6. When generating a travel task, the processor 401 may determine the primary AGV 5 and the secondary AGVs 5, and include primary / subordinate information indicating which AGV 5 is primary or secondary in the travel task. Furthermore, the processor 401 may also include the dimensions of the transported object 6 in the travel task. The processor 401 transmits the travel task through the interface 403.

[0050] Next, we will explain the functions that the processor 501 of the automated guided vehicle 5 will provide. The processor 501 has the function of receiving driving tasks through the communication interface 505.

[0051] The processor 501 has the function of moving to a predetermined location based on a travel task. For example, the processor 501 moves to a predetermined location where the transported object 6 is placed, based on the location information of the transported object 6 included in the travel task.

[0052] The processor 501 has the function of sending a movement completion notification. After moving to a predetermined location included in the driving task, the processor 501 of the subordinate automated guided vehicle 5 establishes a connection with the primary automated guided vehicle 5. Then, the processor 501 of the subordinate automated guided vehicle 5 sends a movement completion notification to the primary automated guided vehicle 5 via the communication interface 505, indicating that it has moved to the predetermined location.

[0053] The processor 501 has the function of raising the lifting device 511 by driving the drive unit 507, thereby lifting the transported object 6. For example, the processors 501 of multiple automated guided vehicles (AGVs) 5 control the multiple AGVs 5 to lift the transported object 6 in a coordinated manner. For example, the processor 501 of the main AGV 5 transmits a timing notification to the subordinate AGVs 5 indicating the timing to lift the transported object 6. Then, according to the timing notification, the processor 501 lifts the transported object 6. Alternatively, the processors 501 of the multiple AGVs 5 may lift the transported object 6 at different timings.

[0054] The processor 501 has a function to calculate the weight and center of gravity of the transported object 6. For example, after the transported object 6 is lifted, the processor 501 receives the measurement result via the pressure-sensitive element 5111. Then, based on the measurement result, the processor 501 calculates the weight and center of gravity of the transported object 6.

[0055] The processor 501 of the main automated guided vehicle 5 has the function of receiving center of gravity information, including the weight and center of gravity position of the transported object 6, from the secondary automated guided vehicle 5.

[0056] Furthermore, the processor 501 of the main automated guided vehicle 5 has a function to calculate the center of gravity of the entire transported object 6. The processor 501 calculates the center of gravity of the entire transported object 6 from the center of gravity information received from the secondary automated guided vehicles 5 and the center of gravity position it has measured. For example, if the number of automated guided vehicles 5 transporting the transported object 6 is, for example, N vehicles (where N is a positive integer of 2 or more), the processor 501 calculates the center of gravity of the entire transported object 6 by adding up all the center of gravity positions and dividing by N.

[0057] The processor 501 of the main automated guided vehicle (AGV) 5 has the function of calculating the control amount of the AGV 5 based on the center of gravity of the entire transported object 6. Here, the control amount includes the moving speed of the AGV 5, the rotational speed of the AGV 5, the amount of movement of the lifting device 511, and the amount of movement of the rotating mechanism 5121 and translational mechanism 5122 included in the inclined stage 512. For example, the processor 501 determines the control amount for each of the multiple AGVs 5 to control the transported object 6 so that its center of gravity does not deviate from the center, based on the center of gravity and the dimensions of the transported object 6. Details of the method for calculating the control amount will be described later.

[0058] The processor 501 of the main automated guided vehicle 5 has the function of transmitting control quantity information indicating the control quantity to each of the subordinate automated guided vehicles 5. The processor 501 transmits control quantity information indicating the control quantity of each of the subordinate automated guided vehicles 5 to each of the subordinate automated guided vehicles 5 via the communication interface 505.

[0059] The processor 501 has the function of driving the drive unit 507 and moving toward the destination. When moving toward the destination, the processor 501 has the function of controlling the operation of the automated guided vehicle 5 so that the center of gravity of the entire transported object 6 does not shift according to the controlled amount. For example, the processor 501 controls the operation of the automated guided vehicle 5 to reduce the shift in the center of gravity due to inertia acting on the transported object 6 when starting, stopping, and changing direction during movement.

[0060] Furthermore, the processor 501 of the main automated guided vehicle (AGV) 5 may, while moving to its destination, continuously or periodically calculate the center of gravity, calculate the center of gravity of the entire transported object 6 from the center of gravity calculated by each AGV 5, calculate the control amount for each AGV 5 from the center of gravity of the entire transported object 6, and transmit the control amount information, including the control amount, to the subordinate AGV 5. In other words, the processor 501 updates the control amount during movement and transmits the updated control amount to the subordinate AGV 5.

[0061] The processor 501 has a function to detect obstacles and other problems using the sensor 506. For example, the processor 501 of the main automated guided vehicle 5 performs obstacle detection based on the sensor information from the sensor 506 to determine whether there are any obstacles or other problems.

[0062] The processor 501 has a function to determine whether the destination has been reached. If it determines that the destination has not been reached, it will continue moving towards the destination according to the driving task.

[0063] On the other hand, if it determines that the destination has been reached, the processor 501 has the function of lowering the transported object 6. Similar to when the transported object 6 was lifted, the processor 501 of the main automated guided vehicle 5 will issue a timing notification, and according to the timing notification, multiple automated guided vehicles 5 may lower the transported object 6 in coordination. Alternatively, multiple automated guided vehicles 5 may lower the transported object 6 at different timings.

[0064] (operation) Next, we will explain the operation flow of the automated guided vehicles (AGVs) 5, using the example where the transported item 6 is a long transported item 6 and the order list for the transported item 6 is an order for receiving goods into storage. First, we will explain the operation of generating a driving task for output to the automated guided vehicle 5 using WCS4.

[0065] Figure 5 is a flowchart showing an example of the driving task generation operation of WCS4 according to the embodiment. The operation of this flowchart is achieved when the WCS4 processor 401 reads and executes the program stored in memory 402.

[0066] First, WMS1 receives an order list for goods receiving and sends it to WES3. The WES3 processor 301 generates a transport work plan based on the order list and sends it to WCS4, thus initiating this flowchart. Although this flowchart describes the operation of WCS4 in receiving operations, it is of course equally applicable to the operation of WCS4 in inventory operations.

[0067] In step ST101, the transport work plan is received. The processor 401 receives the transport work plan transmitted by WES3 via interface 403. Here, the transport work plan includes information such as the location information of the transported object 6 to be transported by the automated guided vehicle 5, the destination of the transported object 6, the weight information of the items to be stored in the transported object 6 during the storage operation, and the destination after the storage operation.

[0068] In step ST102, the processor 401 compares the transport work plan with the transport item information. For example, the processor 401 compares the transport item information stored in memory 402 with the transport work plan. First, the processor 401 extracts information about the transport item 6 included in the transport work plan. Then, the processor 401 refers to the extracted information and the transport item information stored in memory 402 to identify the dimensions of the transport item 6 to be used in the transport work plan. Furthermore, the processor 401 may also refer to the transport item information to identify the weight of the transport item 6.

[0069] In step ST103, the processor 401 determines whether multiple automated guided vehicles (AGVs) 5 are needed. The processor 401 determines whether the transported object 6 used in the transport work plan needs to be transported by multiple AGVs 5. For example, if the width or length of the transported object 6 identified in step ST102 is longer than a predetermined length, the processor 401 determines that the transported object 6 cannot be transported by a single AGV 5, i.e., multiple AGVs 5 are needed. Here, the predetermined length may be a length set in advance by the user, and any length may be set for each width or length of the transported object 6. In such cases, the process proceeds to step ST105. On the other hand, if it is determined that the dimensions of the transported object 6 are less than the predetermined length, i.e., that it can be transported by a single AGV 5, the process proceeds to step ST104.

[0070] Furthermore, the processor 401 may determine that the transported object 6 needs to be transported by multiple automated guided vehicles (AGVs) 5 if the transported object 6 is greater than a predetermined weight and can be transported by multiple AGVs 5. In other words, even if the dimensions of the transported object 6 do not exceed a predetermined length, the processor 401 may determine that multiple AGVs 5 are necessary. For example, if the transported object 6 is heavier than the weight that can be transported by one AGV 5, it needs to be transported by multiple AGVs 5. In such cases, the processor 401 may determine that the transported object 6 needs to be transported by multiple AGVs 5 if its shape allows it to be transported by multiple AGVs 5. The predetermined weight may be a weight determined in advance based on the weight that can be transported by each AGV 5.

[0071] In step ST104, the processor 401 transmits a travel task to one automated guided vehicle 5. The processor 401 generates a travel task based on the transport work plan and transmits the generated travel task to one automated guided vehicle 5 via the interface 403.

[0072] In step ST105, the processor 401 determines the required number of automated guided vehicles (AGVs) 5. For example, if it determines that either the width or the length exceeds a predetermined length, the processor 401 determines that two AGVs 5 are required to transport the transported object 6. Alternatively, if it determines that both the width and the length exceed a predetermined length, the processor 401 determines that four AGVs 5 are required to transport the transported object 6.

[0073] Furthermore, if either the width or the height is a second predetermined length which is longer than a predetermined length, the processor 401 may decide to transport the transported object 6 using three or more automated guided vehicles 5.

[0074] In step ST106, the processor 401 sends a travel task to the determined number of automated guided vehicles (AGVs) 5. The processor 401 generates a travel task based on the transport work plan for the determined number of AGVs 5, for example, N AGVs 5, and sends the travel task to each AGV 5. When generating the travel task, the processor 401 determines which AGVs 5 are primary and which are secondary. The processor 401 then creates primary-subordinate information, which includes the ID of each AGV 5, indicating which AGV 5 is primary and which is secondary. The processor 401 then includes this primary-subordinate information in the travel task. Furthermore, the travel task includes, for example, a movement instruction for the main automated guided vehicle 5 to a forward transport position relative to the direction of movement of the transported object 6 (i.e., the transport position of the transported object 6 by the main automated guided vehicle 5), and a movement instruction for the secondary automated guided vehicle 5 to a rearward transport position relative to the direction of movement of the transported object 6 (i.e., the transport position of the transported object 6 by the secondary automated guided vehicle 5). The processor 401 may also include the dimensions of the transported object 6 in the travel task.

[0075] Next, we will explain the operation when transporting the transported object 6 using multiple automated guided vehicles 5. Figure 6 is a flowchart showing an example of processing by multiple automated guided vehicles 5 when transporting an object 6 according to this embodiment. In this embodiment, for simplicity, we assume that N=2, i.e., that the transported goods 6 are transported by two automated guided vehicles 5 (a first automated guided vehicle 51 and a second automated guided vehicle 52). Furthermore, we assume that the first automated guided vehicle 51 is the primary automated guided vehicle 5, and the second automated guided vehicle 52 is the secondary automated guided vehicle 5.

[0076] The operation of this flowchart is realized by the processor 501 of the automated guided vehicle 5 (the first automated guided vehicle 51 and the second automated guided vehicle 52) reading and executing a program stored in memory such as ROM 502, RAM 503, or auxiliary storage device 504.

[0077] This flowchart is initiated when WCS4 determines, based on the dimensions of the transported object 6, that two automated guided vehicles 5 are required, and sends a travel task to the first automated guided vehicle 51 and the second automated guided vehicle 52, respectively, as explained with reference to Figure 5.

[0078] In steps ST201 and ST202, the processors 501 of the first automated guided vehicle (AGV) 51 and the second AGV 52, respectively, receive a driving task through the communication interface 505. As described above, in this embodiment, the driving task received by each AGV 5 includes master-slave information, which includes instructions that the first AGV 51 is the master and the second AGV 52 is the subordinate, as well as the IDs of the first AGV 51 and the second AGV 52. The first AGV 51 and the second AGV 52 recognize whether they are the master or the subordinate based on this master-slave information.

[0079] In step ST203, the processor 501 of the first automated guided vehicle 51 drives the drive unit 507 and moves to the forward transport position. The processor 501 moves to the forward transport position, which is a predetermined position, in response to the movement instructions included in the travel task.

[0080] In step ST204, the processor 501 of the second automated guided vehicle 52 drives the drive unit 507 to move to the rear transport position. The processor 501 moves to the predetermined position, the rear transport position, in accordance with the movement instructions included in the travel task.

[0081] In step ST205, the processor 501 of the second automated guided vehicle (AGV) 52 sends a movement completion notification to the first AGV 51. For example, the processor 501 of the second AGV 52 establishes a connection with the first AGV 51 using short-range wireless technology. After confirming that the ID included in the movement task matches the ID of the first AGV 51, the processor 501 sends a movement completion notification to the first AGV 51 indicating that the movement to the rear transport position has been completed.

[0082] In steps ST206 and ST207, the processors 501 of the first automated guided vehicle (AGV) 51 and the second AGV 52 each lift the transported object 6. The processor 501 drives the drive unit 507 to raise the lifting device 511 and lift the transported object 6. Here, the first AGV 51 and the second AGV 52 may lift the transported object 6 in coordination or at different timings. If they lift the transported object 6 in coordination, the processor 501 of the first AGV 51 sends a timing notification to the second AGV 52 indicating the timing to lift the transported object 6. The timing notification may be the time to lift the transported object 6, or it may be information indicating the number of seconds until it is lifted. The processor 501 of the second AGV 52 then lifts the transported object 6 according to the timing notification. In other words, the first automated guided vehicle 51 and the second automated guided vehicle 52 lift the transported object 6 simultaneously or approximately simultaneously.

[0083] In steps ST208 and ST209, the processors 501 of the first automated guided vehicle 51 and the second automated guided vehicle 52 measure the weight and center of gravity of the transported object 6. After lifting the transported object 6, the processor 501 receives the measurement results from the pressure-sensitive elements 5111. Based on the measurement results, the processor 501 calculates the weight and center of gravity of the transported object 6. For example, the processor 501 calculates the weight by adding up the measurement results from the pressure-sensitive elements 5111. Furthermore, the processor 501 calculates the center of gravity of the transported object 6 based on the locations where the pressure-sensitive elements 5111 are positioned and the measurement results.

[0084] In step ST210, the processor 501 of the second automated guided vehicle 52 transmits the center of gravity information to the first automated guided vehicle 51. In step ST209, the processor 501 transmits the center of gravity information, including the measured weight and center of gravity position, to the first automated guided vehicle 51.

[0085] In step ST211, the processor 501 of the first automated guided vehicle 51 calculates the center of gravity of the entire transported object 6. The processor 501 calculates the center of gravity of the entire transported object 6 from the center of gravity information from the second automated guided vehicle 52 and the weight and center of gravity measured by the first automated guided vehicle 51 itself. For example, the processor 501 may calculate the overall center of gravity by adding up the measured center of gravity positions and dividing by (N=)2.

[0086] In step ST212, the processor 501 of the first automated guided vehicle 51 calculates the control quantities for each automated guided vehicle 5. For example, based on the overall center of gravity position, the processor 501 determines the control quantities, including the travel speed, rotation speed, lifting device 511, and inclined stage 512, for each of the first automated guided vehicle 51 and the second automated guided vehicle 52.

[0087] For example, if the transported object 6 is moved and the system stops to change direction, the processor 501 needs to control the system so that the center of gravity of the entire transported object 6 does not shift from the center. In this case, the processor 501 of the first automated guided vehicle 51 determines how much movement is required for the inclined stage 512 of the first automated guided vehicle 51 and the second automated guided vehicle 52. That is, the processor 501 determines the amount of movement of the lifting device 511 and the amount of movement of the rotating mechanism 5121 and the translation mechanism 5122. In other words, the processor 501 determines the amount of movement (i.e., control amount) of the inclined stage 512 of the first automated guided vehicle 51 and the second automated guided vehicle 52 so that the center of gravity of the entire transported object 6 is directed towards the center (so that the center of gravity does not shift).

[0088] Alternatively, if the center of gravity shifts due to an external force that cannot be corrected by the movement of the tilting stage 512 alone (e.g., the transported object 6 hitting a person, hitting another transported object 6), the processor 501 of the first automated guided vehicle 51 controls the movement speed and rotation speed of the first automated guided vehicle 51. For example, if the external force is applied in the opposite direction to the direction of travel, the processor 501 of the first automated guided vehicle 51 controls the movement speed to move in the opposite direction, i.e., backward. Since the automated guided vehicle 5 and the transported object 6 are in contact with each other on a surface with a large coefficient of friction, the amount of control at this time is the same for the first automated guided vehicle 51 and the second automated guided vehicle 52.

[0089] In step ST213, the processor 501 of the first automated guided vehicle 51 transmits control quantity information. The processor 501 of the first automated guided vehicle 51 transmits control quantity information, including the control quantity of the second automated guided vehicle 52 determined in step ST212, to the second automated guided vehicle 52 via the communication interface 505.

[0090] In steps ST214 and ST215, the processors 501 of the first automated guided vehicle (AGV) 51 and the second AGV 52 respectively drive the drive unit 507 and move toward the destination. While moving, the processors 501 of the first AGV 51 and the second AGV 52 control the movement speed, rotation speed, lifting device 511, and inclined stage 512, etc., according to the controlled values. That is, the processors 501 control the operation of the AGV 5 (movement speed, rotation speed, operation of the lifting device 511, and inclined stage 512, etc.) so that the center of gravity of the transported object 6 does not shift while moving toward the destination. For example, the processors 501 control the operation of the AGV 5 (for example, the operation of the inclined stage 512) to reduce the shift in the center of gravity of the transported object 6 due to inertia when starting, stopping, and changing direction during movement. For example, when the first automated guided vehicle 51 and the second automated guided vehicle 52 stop, the processors 501 of the first automated guided vehicle 51 and the second automated guided vehicle 52 respectively raise the lifting device 511 of the first automated guided vehicle 51 and lower the lifting device 511 of the second automated guided vehicle 52 in accordance with the control amount, in order to counteract the inertia acting in the direction of travel, and control the operation of the inclined stage 512 in accordance with this up and down movement.

[0091] Furthermore, when moving to the destination, the detection of obstacles using sensors 506, etc., may be performed by the processor 501 of the primary first automated guided vehicle 51, or by the processor 501 of the secondary second automated guided vehicle 52, or by the processors 501 of both the first automated guided vehicle 51 and the second automated guided vehicle 52, respectively.

[0092] Figure 7 shows an example of when the automated guided vehicle 5 changes the direction of travel of the transported object 6. First, as shown in Figure 7(a), assume that the direction of travel of the first automated guided vehicle 51 and the second automated guided vehicle 52 was from the first position P1 to the second position P2 (the first direction). Then, consider the case where this direction of travel is changed to the direction from the second position P2 to the third position P3 (the second direction).

[0093] In this case, as shown in Figure 7(b), the first automated guided vehicle (AGV) 51 changes its direction of travel from the first direction to the second direction at the second position P2. Then, as the first AGV 51 moves from the second position P2 to the third position P3 in the second direction, the second AGV 52 moves from the first position P1 to the second position P2 in the first direction, and then changes its direction of travel to the second direction at the second position P2. As a result, the direction of travel of both the first AGV 51 and the second AGV 52 can be changed from the first direction to the second direction.

[0094] In this case, for example, the processor 501 of the first automated guided vehicle 51 may send an instruction to the second automated guided vehicle 52 via the communication interface 505 to move to the second position P2 in the first orientation and change its direction of travel to the second orientation at the second position P2. Alternatively, such instruction may be included in the driving task. Furthermore, the processor 501 of the first automated guided vehicle 51 may communicate with the second automated guided vehicle 52 to adjust their respective movement speeds and control them so that the lifted position of the transported object 6 does not shift.

[0095] In steps ST216 and ST217, the processors 501 of the first automated guided vehicle (AGV) 51 and the second AGV 52 determine whether they have arrived at their destination. If it is determined that they have not arrived at their destination, the process returns to steps ST208 and ST209, respectively. That is, while moving, the processor 501 of the first AGV 51 calculates the center of gravity of the entire transported object 6 and continuously updates the control parameters of the AGV 5 based on this center of gravity. The processors 501 of the first AGV 51 and the second AGV 52 then control the operation of the first AGV 51 and the second AGV 52 respectively according to the updated control parameters, so that the center of gravity of the entire transported object 6 does not deviate from the center.

[0096] In this case, step ST212 may be skipped. For example, the control variable may be updated only when the center of gravity of the entire transported object 6 moves beyond a predetermined threshold. This reduces the processing load on the processor 501 of the main automated guided vehicle 5. Furthermore, it also reduces the amount of communication between the main automated guided vehicle 5 and the secondary automated guided vehicle 5.

[0097] On the other hand, if it is determined that the destination has been reached, the process proceeds to steps ST218 and ST219.

[0098] In steps ST218 and ST219, the processors 501 of the first automated guided vehicle 51 and the second automated guided vehicle 52 each lower the transported object 6. The processor 501 lowers the lifting device 511 by driving the drive unit 507 and lowers the transported object 6. Here, the first automated guided vehicle 51 and the second automated guided vehicle 52 may lower the transported object 6 simultaneously or approximately simultaneously, or they may lower the transported object 6 at different timings.

[0099] If it is not necessary to unload the transported object 6 at the destination, steps ST218 and ST219 may be skipped. In this case, when the first automated guided vehicle 51 and the second automated guided vehicle 52 receive a travel task again, they may start from steps ST208 and ST209.

[0100] (Effects of the embodiment) According to the embodiment described above, multiple automated guided vehicles (AGVs) 5 are directly connected to each other, and the amount of control for their operation is determined by the main AGV 5. This makes it possible to stably transport long transportable objects 6 and other transportable objects 6 required by multiple AGVs 5.

[0101] Furthermore, since multiple automated guided vehicles (AGVs) 5, each designed to transport a single object 6, can coordinate the transport of that single object 6, the application environment for the AGVs 5 can be expanded.

[0102] [Other embodiments] In one embodiment, an example was described in which WCS4 creates a travel task from the transport work plan, but WES3 may also create a travel task from the transport work plan and send it to WCS4.

[0103] A program according to one embodiment may be transferred while stored in an electronic device (computer) such as an automated guided vehicle 5, or it may be transferred without being stored in an electronic device. In the latter case, the program may be transferred via a network, or it may be transferred while stored in a storage medium. The storage medium is a non-temporary tangible medium. The storage medium is a medium that can be read by a computer such as an automated guided vehicle 5 (computer-readable medium). The storage medium may be any medium that can store a program and is read by a computer, such as an optical disc (e.g., CD-ROM), a magnetic disc, or a semiconductor memory (e.g., a memory card), and its form is not limited.

[0104] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0105] S...Warehouse System 1…WMS 2…Warehouse processing system 3…WES 301… Processor 302...Memory 303… Interface 4…WCS 401… Processor 402...Memory 403… Interface 5, 51, 52... Automated Guided Vehicles 501… Processor 502...ROM 503…RAM 504... Auxiliary storage device 505...Communication Interface 506...Sensor 507…Drive unit 508...Battery 509…Charging mechanism 510... Tires 511... Lifting device 5111... Pressure-sensitive element 512... Inclined stage 5121... Rotation mechanism 5122…Translation mechanism 6… Transported goods P1, P2, P3…Position

Claims

1. It is an automated guided vehicle, A communication interface that receives a driving task including an instruction to transport an object using multiple automated guided vehicles, including the aforementioned automated guided vehicle, Based on the aforementioned driving task, the transported object moves to the position where it is placed. Through the aforementioned communication interface, a connection is established with other automated guided vehicles among the plurality of automated guided vehicles. The lifting device included in the aforementioned automated guided vehicle is controlled to lift the transported object, Based on the measurement results of the pressure-sensitive element placed on the upper surface of the lifting device, the center of gravity of the transported object is measured. Based on the measured center of gravity position, a control quantity is calculated to control the operation of the multiple automated guided vehicles. The operation of the automated guided vehicle is controlled so that the center of gravity of the transported object does not shift while it is moving toward the destination according to the aforementioned driving task. Processor and An automated guided vehicle equipped with the following features.

2. The aforementioned processor, Through the aforementioned communication interface, the center of gravity information obtained by measuring the center of gravity position of the transported object is further received from the other automated guided vehicle. Based on the measured center of gravity position and the center of gravity information, including the center of gravity position of the transported object, transmitted from the other automated guided vehicle, the center of gravity position of the entire transported object is calculated. Based on the center of gravity of the entire conveyed object, the control amount is calculated. The control amount information, including the control amount, is transmitted to the other automated guided vehicle via the aforementioned communication interface. The automated guided vehicle according to claim 1.

3. The processor, while traveling to the destination, Through the aforementioned communication interface, the center of gravity information obtained by measuring the center of gravity position of the transported object is further received from the other automated guided vehicle. Based on the measurement results of the pressure-sensitive element, the center of gravity of the entire transported object is further measured. The control quantity is updated based on the aforementioned center of gravity position and the center of gravity information received from the other automated guided vehicle. The automated guided vehicle according to claim 2.

4. The processor updates the control amount when the center of gravity of the entire transported object changes by more than a predetermined threshold. The automated guided vehicle according to claim 3.

5. The aforementioned processor, The amount of motion used to control the inclination of the inclined stage is calculated using an inclined stage equipped with a rotation mechanism having at least a rotation axis in the direction of movement. The tilt of the tilting stage is controlled according to the amount of movement. The automated guided vehicle according to claim 2.

6. The inclined stage comprises a two-axis rotation mechanism located below the lifting device and further having a rotation axis perpendicular to the direction of movement, and a translation mechanism located below the two-axis rotation mechanism that allows the lifting device to move horizontally. The control amount further includes the operating amounts of the two-axis rotation mechanism and the translation mechanism and the operating amount of the lifting device. The automated guided vehicle according to claim 5.

7. The control quantities further include the moving speed and rotational speed of the automated guided vehicle. The automated guided vehicle according to claim 2.

8. The aforementioned driving task further includes primary / subordinate information indicating that the aforementioned automated guided vehicle is the primary vehicle and the other automated guided vehicles are secondary. The automated guided vehicle according to claim 1.

9. The processor performs obstacle detection when moving according to the driving task. The automated guided vehicle according to claim 8.

10. The aforementioned travel task includes an instruction to move to a forward transport position which is ahead of the direction of travel of the transported object, and the aforementioned move to another automated guided vehicle task includes an instruction to move to a rear transport position which is behind the direction of travel of the transported object. The automated guided vehicle according to claim 8.

11. The processor, after moving to the forward transport position, connects with the other automated guided vehicle via the communication interface and receives a movement completion notification indicating that it has moved to the rear transport position. The automated guided vehicle according to claim 10.

12. The processor, upon receiving notification of the completion of movement with the other automated guided vehicle, controls the lifting device to lift the transported object in coordination with the other automated guided vehicle. The automated guided vehicle according to claim 11.

13. When the transported object is a long object and there is only one other automated guided vehicle, and the direction of travel is changed from the first direction to the second direction, the processor shall The drive unit is controlled at the first position to change the direction of travel from the first direction to the second direction. Through the communication interface, an instruction is transmitted to the other automated guided vehicle to move to the first position in the first orientation, and then change the direction of travel to the second orientation. The automated guided vehicle according to claim 1.

14. An automated guided vehicle (AGV) control method executed by the AGV's processor, The system receives a driving task that includes instructions to transport an object using multiple automated guided vehicles, including the aforementioned automated guided vehicle. Based on the aforementioned driving task, the transported object moves to the position where it is placed, To establish a connection with other automated guided vehicles among the aforementioned plurality of automated guided vehicles, The aforementioned automated guided vehicle controls the lifting device to lift the transported object, The center of gravity of the transported object is measured based on the measurement results of a pressure-sensitive element placed on the upper surface of the lifting device, Based on the measured center of gravity position, a control amount is calculated to control the operation of the multiple automated guided vehicles. The operation of the automated guided vehicle is controlled so that the center of gravity of the transported object does not shift while it is moving to the destination in accordance with the aforementioned driving task, An automated guided vehicle control method comprising the above.

15. An automated guided vehicle (AGV) control program comprising instructions to be executed by the AGV's processor, wherein the instructions are: The system receives a driving task that includes instructions to transport an object using multiple automated guided vehicles, including the aforementioned automated guided vehicle. Based on the aforementioned driving task, the transported object moves to the position where it is placed, To establish a connection with other automated guided vehicles among the aforementioned plurality of automated guided vehicles, The aforementioned automated guided vehicle controls the lifting device to lift the transported object, The center of gravity of the transported object is measured based on the measurement results of a pressure-sensitive element placed on the upper surface of the lifting device, Based on the measured center of gravity position, a control amount is calculated to control the operation of the multiple automated guided vehicles. The operation of the automated guided vehicle is controlled so that the center of gravity of the transported object does not shift while it is moving to the destination in accordance with the aforementioned driving task, An automated guided vehicle control program equipped with the following features.

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