Pallet and loading system

Abstract

To provide a pallet which can prevent a load collapse when the pallet is tilted.SOLUTION: A pallet (1) comprises: an upper plate (11) on which a load is placed; a lower frame (12) which is arranged opposite to the upper plate (11); at least three force sensors (13A to 13D) which are arranged at a lower face of the upper plate (11) or an upper face of the lower frame (12); at least three lifting / lowering mechanisms (15A to 15D) which are arranged between the upper plate (11) and the lower frame (12) via the force sensors (13A to 13D) and can lift and lower the upper plate relative to the lower frame; and a controller (16) which drive-controls the at least three lifting / lowering mechanisms (15A to 15D) based on output signals of the at least three force sensors (13A to 13D).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pallet and a loading system.

Background Art

[0002] Patent Document 1 describes a pallet for a forklift in which an insertion hole for inserting a fork extending forward of the forklift is provided through, and a mark recognizable by a driver is formed near the entrance of the insertion hole.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When loading goods onto such a pallet for a forklift, if the weight of the goods and the center of gravity of the entire pallet are not considered, the center of gravity of the entire pallet may shift. As a result, there is a risk of cargo collapse during transportation by a forklift or the like. In addition, when a vehicle such as a truck carrying a pallet travels on a slope, the loading platform may tilt, causing a risk of cargo collapse.

[0005] One aspect of the present invention has been made in view of the above-described problems, and an object thereof is to provide a pallet and a loading system capable of suppressing cargo collapse when the pallet is tilted.

Means for Solving the Problems

[0006] In order to solve the above problems, in the pallet according to one aspect of the present invention, there are provided an upper plate on which a load is placed, a lower frame disposed opposite to the upper plate, at least three force sensors disposed on the lower surface of the upper plate or the upper surface of the lower frame, at least three elevating mechanisms disposed between the upper plate and the lower frame via the force sensors and capable of raising and lowering the upper plate with respect to the lower frame, and a controller that drives and controls the at least three elevating mechanisms based on output signals of the at least three force sensors.

Advantages of the Invention

[0007] According to one aspect of the present invention, when the pallet with a load placed on the upper plate is tilted, the controller can drive and control at least three elevating mechanisms based on the output signals of at least three force sensors to bring the upper plate closer to a horizontal state. As a result, when the pallet is tilted, the controller can prevent the load from collapsing.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0009] Hereinafter, Embodiment 1 and Embodiment 2 in which the present invention is embodied will be described in detail with reference to the drawings. The same or equivalent components and members shown in each drawing are denoted by the same reference numerals, and redundant explanations will be omitted as appropriate.

[0010] [Embodiment 1] [Schematic Configuration of Pallet 1] First, the schematic configuration of the pallet 1 according to Embodiment 1 of the present disclosure will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing an example of the schematic configuration of the pallet 1 according to Embodiment 1. FIG. 2 is a plan view showing an example of the schematic configuration of the pallet 1 according to Embodiment 1. As shown in FIGS. 1 and 2, the pallet 1 includes an upper plate 11, a lower frame 12, four force sensors 13A to 13D, four elevating mechanisms 15A to 15D, a controller 16, and a battery 17.

[0011] The upper plate 11 is made of wood or resin and is formed in a flat plate shape that is rectangular in plan view. The upper plate 11 has a load placed on its upper surface. At the four corners of the lower surface of the upper plate 11, force sensors 13A to 13D that are rectangular in plan view and have a predetermined thickness are attached.

[0012] The lower frame 12 is made of wood or resin and formed in a flat plate shape. It is formed in a rectangular shape in plan view with substantially the same size as the upper plate 11, and is disposed to face the lower side of the upper plate 11. At the four corners of the upper surface of the lower frame 12, elevating mechanisms 15A to 15D that are rectangular in plan view and whose upper end portions are movable in the vertical direction are attached. And the lower frame 12 has the lower end portions of the respective force sensors 13A to 13D of the upper plate 11 attached to the upper end portions of the respective elevating mechanisms 15A to 15D, and is attached to the lower surface of the upper plate 11 via the respective force sensors 13A to 13D and the respective elevating mechanisms 15A to 15D.

[0013] Each of the force sensors 13A to 13D is a three-axis force sensor that detects force components FX, FY, and FZ in the three-axis directions of the X-axis, Y-axis, and Z-axis of a force sensor coordinate system whose axial direction is the Z-axis direction. Each of the force sensors 13A to 13D is attached to the lower surface of the upper plate 11 such that the Z-axis direction is the vertical direction. Note that the force sensor 13 may be a six-axis force sensor that detects force components FX, FY, and FZ in the three-axis directions of the X-axis, Y-axis, and Z-axis of a force sensor coordinate system whose axial direction is the Z-axis direction, and moment components MX, MY, and MZ having the three axes of the X-axis, Y-axis, and Z-axis as rotation axes.

[0014] [Schematic Configuration of Elevating Mechanisms 15A to 15D] The schematic configuration of the elevating mechanisms 15A to 15D will be described with reference to FIG. 3. FIG. 3 is a perspective view showing an example of the elevating mechanism 15A. Since the elevating mechanisms 15A to 15D have the same configuration, the elevating mechanism 15A will be described. As shown in FIG. 3, the elevating mechanism 15A includes a top plate portion 21 that is flat and rectangular in plan view, a bottom plate portion 22 that is flat and rectangular in plan view, a pair of link mechanisms 23A and 23B that are disposed opposite to each other, a screw shaft 25, and a motor 26A that rotationally drives the screw shaft 25. Each of the elevating mechanisms 15A to 15D includes motors 26A to 26D that rotationally drive their respective screw shafts 25. The motors 26A to 26D are composed of stepping motors, DC servo motors, or the like.

[0015] The upper surface of the top plate portion 21 is attached to the lower end surface of the force sensor 13A by means such as screwing, and is attached to the lower surface of the upper plate 11 via the force sensor 13A. On both side edges of the top plate portion 21 facing the upper end portions of the pair of link mechanisms 23A and 23B, upper mounting ribs 27A and 27B protruding in a rib shape over the entire width are provided. Also, the lower surface of the bottom plate portion 22 is placed on the upper surface of the lower frame 12 and attached by means such as screwing. On both side edges of the bottom plate portion 22 facing the lower end portions of the pair of link mechanisms 23A and 23B, lower mounting ribs 28A and 28B protruding in a rib shape over the entire width are provided.

[0016] The pair of link mechanisms 23A and 23B has a pantograph structure in which a pair of links are stacked in two stages in the vertical direction in an X-shaped structure and are connected in a telescopic displacement-capable manner. Among the upper end portions of the upper X-shaped structure, the upper end portion on the motor 26A side is rotatably fixed to the upper mounting ribs 27A and 27B via a pivot shaft 29A spanned between the pair of link mechanisms 23A and 23B. Among the upper end portions of the upper X-shaped structure, the upper end portion on the side opposite to the motor 26A is engaged with the upper mounting ribs 27A and 27B via a pivot shaft 29B spanned between the pair of link mechanisms 23A and 23B so as to be slidable parallel to the top plate portion 21.

[0017] Each lower end portion of the pair of links of the upper X-shaped structure and each upper end portion of the pair of links of the lower X-shaped structure are rotatably connected with the rotation shaft support members 31 and 32 spanned between the pair of link mechanisms 23A and 23B as fulcrums. Among the lower end portions of the lower X-shaped structure, the lower end portion on the motor 26A side is rotatably fixed to the lower mounting ribs 28A and 28B via a pivot shaft 29C spanned between the pair of link mechanisms 23A and 23B. Among the lower end portions of the lower X-shaped structure, the lower end portion on the side opposite to the motor 26A is engaged with the lower mounting ribs 28A and 28B via a pivot shaft 29D spanned between the pair of link mechanisms 23A and 23B so as to be slidable parallel to the bottom plate portion 22.

[0018] The screw shaft 25 is screwed into and inserted through a screw hole formed in the rotation shaft support member 32 on the motor 26A side, and the tip thereof is rotatably fixed to the rotation shaft support member 31 disposed opposite to the rotation shaft support member 32. Further, the motor 26A is rotatably connected to the rear end portion of the screw shaft 25.

[0019] Therefore, in the lifting mechanism 15A configured as described above, when the screw shaft 25 is rotated, for example, in the clockwise direction via the motor 26A, the rotation shaft support members 31 and 32 approach each other, the pair of link mechanisms 23A and 23B extend, and the top plate portion 21 rises. As a result, the upper plate 11 rises via the force sensor 13A. On the other hand, when the screw shaft 25 is rotated, for example, in the counterclockwise direction via the motor 26A, the rotation shaft support members 31 and 32 move away from each other, the pair of link mechanisms 23A and 23B contract, and the top plate portion 21 descends. As a result, the upper plate 11 descends via the force sensor 13A.

[0020] Further, as shown in FIG. 1, the controller 16 is provided with a start switch 16A as an example of an operation unit. The battery 17 is composed of a lithium ion battery or the like and supplies power to the controller 16, the force sensors 13A to 13D, and the motors 26A to 26D.

[0021] [Electrical Configuration of Pallet 1] Next, the electrical configuration of the pallet 1 will be described with reference to FIG. 4. FIG. 4 is a block diagram showing an example of the electrical configuration of the pallet 1. As shown in FIG. 4, the pallet 1 includes a controller 16, a start switch 16A, force sensors 13A to 13D, and motors 26A to 26D.

[0022] The controller 16 is composed of, for example, a CPU (Central Processing Unit) 161, a ROM (Read Only Memory) 162, a RAM (Random Access Memory) 163, a storage unit 164, etc. The storage unit 164 is composed of a flash memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), etc. The CPU 161 executes various arithmetic processes based on various programs and various parameters stored in the ROM 162. The RAM 163 temporarily stores the arithmetic results and data of the CPU 161. The storage unit 164 stores data such as the pressure center described later.

[0023] A start switch 16A, each force sensor 13A to 13D, and each motor 26A to 26D are electrically connected to the controller 16. The start switch 16A is composed of a button switch, and by pressing the button switch, for example, the execution of the upper plate lifting control process shown in FIG. 5 can be instructed. Further, the controller 16 stores the output signals input from each force sensor 13A to 13D in the RAM 163. Further, the controller 16 rotationally drives and controls each motor 26A to 26D to control the lifting of each lifting mechanism 15A to 15D.

[0024] [Upper Plate Lifting Control Process] Next, an example of the upper plate lifting control process executed by the controller 16 of the pallet 1 configured as described above will be described with reference to FIGS. 5 to 8. FIG. 5 is a flowchart showing an example of the upper plate lifting control process executed by the controller 16. FIG. 6 is a front view showing an example of the pressure center when the pallet 1 is in a horizontal state. FIG. 7 is a front view showing an example of the pressure center when the pallet 1 is tilted. FIG. 8 is a diagram schematically showing an example of the operation of the pallet 1 placed on the loading platform 38A of the truck 38.

[0025] As shown in FIG. 5, in step S11, the controller 16 determines whether the start switch 16A has been pressed and turned ON. Then, when the controller 16 determines that the start switch 16A has not been pressed and is OFF (S11: NO), the upper plate lifting control process ends. On the other hand, when the controller 16 determines that the start switch 16A has been pressed and turned ON (S11: YES), the process proceeds to step S12.

[0026] In step S12, the controller 16 detects the three-axis force components FX, FY, and FZ (output signals when horizontal) acting on the respective force sensors 13A to 13D by the load placed on the upper plate 11 of the pallet 1 in the horizontal state, that is, the pallet 1 placed horizontally. Then, the controller 16 calculates the forces FA, FB, FC, and FD acting on the respective force sensors 13A to 13D from the three-axis force components FX, FY, and FZ of the respective force sensors 13A to 13D. Subsequently, the controller 16 calculates the position on the upper plate 11 where the sum of the forces F1 = FA + FB + FC + FD acts, and stores it in the storage unit 164 as the first center of pressure (COP) 36 of the load placed on the upper plate 11. After that, the controller 16 proceeds to the process of step S13.

[0027] For example, as shown in FIG. 6, the controller 16 detects the three-axis force components FX, FY, and FZ acting on the respective force sensors 13A to 13D by the load 35 placed on the upper plate 11 of the pallet 1 placed horizontally. Then, the controller 16 calculates the forces FA, FB, FC, and FD acting on the respective force sensors 13A to 13D from the three-axis force components FX, FY, and FZ of the respective force sensors 13A to 13D.

[0028] Subsequently, the controller 16 calculates the position on the upper plate 11 where the sum of the forces FA, FB, FC, and FD, F1 = FA + FB + FC + FD, acts, and stores it in the storage unit 164 as the first pressure center 36 of the load 35 placed on the upper plate 11. As shown in FIGS. 2 and 6, when the center of gravity G1 of the load 35 is located on the perpendicular line passing through the intersection of the diagonal lines of the upper plate 11, that is, the center position 11A of the upper plate 11, the first pressure center 36 coincides with the center position 11A of the upper plate 11.

[0029] As shown in FIG. 5, in step S13, the controller 16 determines whether it is the timing when a predetermined time, for example, about 1 second to 5 seconds, has elapsed since the start of the process of step S13. Then, when the controller 16 determines that it is not the timing when the predetermined time has elapsed (S13: NO), it executes the process of step S13 again. On the other hand, when the controller 16 determines that it is the timing when the predetermined time has elapsed (S13: YES), it proceeds to the process of step S14.

[0030] In step S14, the controller 16 detects the three-axis force components FX, FY, and FZ (current output signals) acting on each of the force sensors 13A to 13D by the load placed on the upper plate 11 of the pallet 1. Then, the controller 16 calculates the forces FA, FB, FC, and FD acting on each of the force sensors 13A to 13D from the three-axis force components FX, FY, and FZ of each of the force sensors 13A to 13D. Subsequently, the controller 16 calculates the position on the upper plate 11 where the sum of the forces FA, FB, FC, and FD, F2 = FA + FB + FC + FD, acts, and stores it in the storage unit 164 as the second pressure center (COP: Center of Pressure) 37 of the load placed on the upper plate 11. After that, the controller 16 proceeds to the process of step S15.

[0031] For example, as shown in FIG. 7, the controller 16 detects the force components FX, FY, and FZ in the three-axis directions acting on each of the force sensors 13A to 13D by the load 35 placed on the upper plate 11 of the inclined pallet 1. Then, the controller 16 calculates the forces FA, FB, FC, and FD acting on each of the force sensors 13A to 13D from the force components FX, FY, and FZ in the three-axis directions of each of the force sensors 13A to 13D.

[0032] Subsequently, the controller 16 calculates the position on the upper plate 11 where the sum F2 = FA + FB + FC + FD of the forces FA, FB, FC, and FD acts, and stores it in the storage unit 164 as the second pressure center 37 of the load 35 placed on the upper plate 11. As shown in FIGS. 2 and 7, when the center of gravity G1 of the load 35 is located on the perpendicular line passing through the intersection of the diagonal lines of the upper plate 11, that is, the center position 11A of the upper plate 11, the second pressure center 37 is located at a position separated from the center position 11A of the upper plate 11 by a distance L1.

[0033] As shown in FIG. 5, in step S15, the controller 16 reads the first pressure center 36 and the second pressure center 37 from the storage unit 164. Then, the controller 16 determines whether the second pressure center 37 is located within a predetermined range centered on the first pressure center 36, for example, within a circle with a radius of about 1 cm to 3 cm. For example, as shown in FIGS. 2 and 7, when the center of gravity G1 of the load 35 is located on the perpendicular line passing through the center position 11A of the upper plate 11, the controller 16 determines whether the second pressure center 37 is located within the circle 39 centered on the center position 11A of the upper plate 11. Note that the predetermined range centered on the first pressure center 36 is not limited to a circle, and may be a polygon such as a quadrilateral, pentagon, or hexagon.

[0034] When the controller 16 determines that the second pressure center 37 is located within a predetermined range centered on the first pressure center 36 (S15: YES), without changing the inclination of the upper plate 11, the process proceeds to the process of step S17 described later. On the other hand, when the controller 16 determines that the second pressure center 37 is not located within a predetermined range centered on the first pressure center 36 (S15: NO), the process proceeds to the process of step S16 to make the inclination of the upper plate 11 of the pallet 1 approach horizontal.

[0035] In step S16, the controller 16 drives each of the elevating mechanisms 15A to 15D so that the second pressure center 37 is located within a predetermined range centered on the first pressure center 36. After making the upper plate 11 approach horizontal, the process proceeds to the process of step S17. Specifically, the controller 16 rotationally drives each of the motors 26A to 26D of the elevating mechanisms 15A to 15D, rotationally drives each of the screw shafts 25 clockwise or counterclockwise, and raises and lowers the corner portions of the upper plate 11 via the force sensors 13A to 13D. Thereby, it is possible to eliminate the inclination of the load on the upper plate 11 of the pallet 1 and suppress the collapse of the load.

[0036] For example, as shown in FIG. 8, when the truck 38 with the pallet 1 on which the load 41 is placed mounted on the loading platform 38A travels on a slope, stops on a slope, or parks, the controller 16 drives each of the elevating mechanisms 15A to 15D to make the upper plate 11 approach horizontal. Note that, instead of the battery 17, power may be supplied from a battery (not shown) mounted on the truck 38 to the motors 26A to 26D of the elevating mechanisms 15A to 15D for the pallet 1 mounted on the loading platform 38A of the truck 38.

[0037] Specifically, the controller 16 rotationally drives the motors 26A and 26B of the front-side (the traveling direction side of the track 38) elevating mechanisms 15A and 15B to rotationally drive each screw shaft 25 counterclockwise. Thereby, the controller 16 lowers both corner portions on the front side of the upper plate 11 via the respective force sensors 13A and 13B. Further, the controller 16 rotationally drives the motors 26C and 26D of the elevating mechanisms 15C and 15D to rotationally drive each screw shaft 25 clockwise. Thereby, the controller 16 raises both corner portions on the rear side (the side opposite to the traveling direction of the track 38) of the upper plate 11 via the respective force sensors 13C and 13D to bring the upper plate 11 closer to the horizontal state.

[0038] As shown in FIG. 5, in step S17, the controller 16 determines whether or not the start switch 16A has been pressed and turned OFF. And when the controller 16 determines that the start switch 16A has not been pressed and is ON (S17: NO), it executes the processing after step S13 again. On the other hand, when the controller 16 determines that the start switch 16A has been pressed and is OFF (S17: YES), it ends the upper plate elevation control process.

[0039] As described in detail above, in the pallet 1 according to the first embodiment, the controller 16 calculates the first pressure center 36 on the upper plate 11 of the horizontally placed pallet 1 based on the output signals of the respective force sensors 13A to 13D. And the controller 16 calculates the second pressure center 37 on the upper plate 11 of the pallet 1 based on the output signals of the respective force sensors 13A to 13D every time a predetermined time elapses.

[0040] And when the controller 16 determines that the second pressure center 37 is not located within a predetermined range from the first pressure center 36, it drives and controls the motors 26A to 26D of the elevating mechanisms 15A to 15D so that the second pressure center 37 is located within a predetermined range from the first pressure center 36. Thereby, the controller 16 can bring the upper plate 11 closer to the horizontal state and can suppress the collapse of the load on the pallet 1.

[0041] [Embodiment 2] [Schematic Configuration of Loading System 100] Next, the loading system 100 according to Embodiment 2 of the present disclosure will be described with reference to FIG. 9. FIG. 9 is an explanatory diagram for explaining the schematic configuration of the loading system 100 according to Embodiment 2. For convenience of explanation, members having the same functions as those described in Embodiment 1 are denoted by the same reference numerals, and their descriptions will not be repeated.

[0042] As shown in FIG. 9, the loading system 100 includes the pallet 1 according to Embodiment 1, a robot 51, and a loading control device 61. The robot 51 includes a robot arm 52, a robot hand 55, a hand force sensor 56, and a robot controller 57. The robot arm 52 is an articulated arm including a plurality of arms 52A. The robot arm 52 has five arms 52A connected by four joints 52B.

[0043] Each joint 52B is provided with a first joint motor 53A, a second joint motor 53B, a third joint motor 53C, and a fourth joint motor 53D for operating the joint 52B. However, the number of arms 52A included in the robot arm 52 is not limited to five, and the number of joints 52B connecting the arms 52A is not limited to four.

[0044] The robot hand 55 is configured to be able to grip a load by two claws 58 that are opened and closed by an actuator 55A shown in FIG. 10. The robot hand 55 is attached to the robot arm 52 via the hand force sensor 56. The robot arm 52 has six degrees of freedom and supports the position and posture of the robot hand 55 to be changeable.

[0045] The hand force sensing sensor 56 detects the direction and magnitude of the force and moment acting on itself. The hand force sensing sensor 56 is a six-axis force sensing sensor that detects the force components FX, FY, FZ in the three-axis directions of the X-axis, Y-axis, and Z-axis of the force sensing sensor coordinate system with the axial direction as the Z-axis direction, and the moment components MX, MY, MZ with the three axes of the X-axis, Y-axis, and Z-axis as the rotation axes. The hand force sensing sensor 56 is arranged coaxially with the robot hand 55.

[0046] Therefore, the hand force sensing sensor 56 detects the force components FX, FY, FZ in the three-axis directions of the X-axis, Y-axis, and Z-axis acting on the robot hand 55, and the moment components MX, MY, MZ with the three axes of the X-axis, Y-axis, and Z-axis as the rotation axes. Hereinafter, FX, FY, FZ, MX, MY, MZ will also be referred to as force components or simply detection values. The hand force sensing sensor 56 outputs a signal regarding the detection value to the robot controller 57.

[0047] [Electrical Configuration of Robot Controller 57] Next, the schematic configuration of the robot controller 57 will be described with reference to FIG. 10. FIG. 10 is a block diagram showing an example of the electrical configuration of the loading system 100. As shown in FIG. 10, the robot controller 57 is composed of, for example, a CPU (Central Processing Unit) 571, a ROM (Read Only Memory) 572, a RAM (Random Access Memory) 573, and the like. The CPU 571 executes various arithmetic processes based on various programs and various parameters stored in the ROM 572. The RAM 573 temporarily stores the arithmetic results and data of the CPU 571.

[0048] The robot controller 57 is electrically connected to the hand force sensing sensor 56, an actuator 55A that opens and closes the two claws 58 of the robot hand 55, and the first joint motor 53A to the fourth joint motor 53D. Further, the robot controller 57 is configured to be communicable with the loading control device 61 by wire or wirelessly.

[0049] When the robot controller 57 receives a transmission request instruction from the loading control device 61, it transmits the detection signal of the hand force sensor 56 to the loading control device 61. Further, the robot controller 57 drives and controls the actuator 55A and the first to fourth joint motors 53A to 53D according to various operation instructions received from the loading control device 61 and according to various programs stored in the ROM 572.

[0050] [Electrical Configuration of Loading Control Device 61] The loading control device 61 is configured to be communicable, either wired or wirelessly, between the controller 16 of the pallet 1 and the robot controller 57. Note that the loading control device 61, the controller 16, and the robot controller 57 may be connected to a network such as the Internet or a LAN. And the loading control device 61 may communicate between the controller 16 and the robot controller 57 via the network.

[0051] The loading control device 61 sets the installation position of the load held by the robot hand 55 on the upper plate 11 based on the pressure center (third pressure center) of the load placed on the upper plate 11 of the pallet 1 and the weight and center of gravity of the load held by the robot hand 55. Then, the loading control device 61 controls the robot 51 to install the load at the installation position on the upper plate 11.

[0052] The electrical configuration of the loading control device 61 will be described with reference to FIG. 10. As shown in FIG. 10, the loading control device 61 includes an acquisition unit 62, an analysis unit 63, an output unit 64, and a model storage unit 65. The analysis unit 63 and the model storage unit 65 constitute a setting unit 66 for setting the installation position of the load.

[0053] The acquisition unit 62 requests the controller 16 of the pallet 1 to calculate and transmit the pressure center of the load placed on the upper plate 11. Then, the acquisition unit 62 acquires the pressure center of the load placed on the upper plate 11 from the controller 16. Further, the acquisition unit 62 receives detection signals of the force components FX, FY, FZ in the three-axis directions of the hand force sensor 56 and the moment components MX, MY, MZ with the three axes of the X-axis, Y-axis, and Z-axis as rotation axes from the robot controller 57. Then, the acquisition unit 62 acquires the weight and the center of gravity of the load gripped by the robot hand 55 from the force components FX, FY, FZ in the three-axis directions of the hand force sensor 56 and the moment components MX, MY, MZ with the three axes of the X-axis, Y-axis, and Z-axis as rotation axes.

[0054] The analysis unit 63 inputs the weight and the center of gravity of the load gripped by the robot hand 55 acquired by the acquisition unit 62 and the pressure center of the load placed on the upper plate 11 of the pallet 1 into the learned model stored in the model storage unit 65, and estimates the installation position of the load on the upper plate 11. The output unit 64 transmits the installation position of the load on the upper plate 11 estimated by the analysis unit 63 to the robot controller 57 as the installation position of the load gripped by the robot hand 55 on the upper plate 11, and instructs the installation of the load on the upper plate 11. Further, the output unit 64 outputs various request instructions to the robot controller 57.

[0055] The model storage unit 65 stores a learned model generated by a model generation device (not shown). The learned model is generated by machine learning using, as teacher data, the weight and the center of gravity of the load gripped by the robot hand 55, the pressure center on the upper plate 11 of the pallet 1, and the installation position of the load gripped by the robot hand 55 on the upper plate 11 where the position of the pressure center of the upper plate 11 approaches the center position 11A of the upper plate 11. Therefore, the learned model is a model learned to output the installation position of the load gripped by the robot hand 55 on the upper plate 11 where the position of the pressure center of the upper plate 11 approaches the center position 11A of the upper plate 11 when the weight and the center of gravity of the load gripped by the robot hand 55 and the pressure center on the upper plate 11 of the pallet 1 are input.

[0056] [Loading Control Process] Next, with reference to FIG. 11, a loading control process for placing a load on the upper plate 11 of the pallet 1 by the robot 51, which is executed by the loading control device 61 of the loading system 100 configured as described above, will be described. FIG. 11 is a flowchart showing an example of the loading control process executed by the loading control device 61. When a load placement instruction for the upper plate 11 is input by the user, the loading control device 61 executes the loading control process shown in FIG. 11. The program shown as a flowchart in FIG. 11 is stored in advance in a ROM (not shown).

[0057] As shown in FIG. 11, in step S21, after the loading control device 61 outputs a load gripping instruction for instructing the robot controller 57 to grip the load to be placed on the upper plate 11 via the output unit 64, the process proceeds to step S22. Thereby, the loading control device 61 can instruct the robot 51 to grip the load to be placed on the upper plate 11 by the robot hand 55.

[0058] In step S22, the loading control device 61 instructs the robot controller 57 via the output unit 64 to transmit detection signals of the force components FX, FY, FZ in the three-axis directions of the hand force sensor 56 and the moment components MX, MY, MZ having the three axes of the X-axis, Y-axis, and Z-axis as rotation axes. Then, the loading control device 61 acquires the force components FX, FY, FZ in the three-axis directions of the hand force sensor 56 and the moment components MX, MY, MZ having the three axes of the X-axis, Y-axis, and Z-axis as rotation axes via the acquisition unit 62, and then the process proceeds to step S23.

[0059] In step S23, the loading control device 61 detects the weight and center of gravity of the load gripped by the robot hand 55 from the force components FX, FY, FZ in the three-axis directions of the hand force sensor 56 and the moment components MX, MY, MZ having the three axes of the X-axis, Y-axis, and Z-axis as rotation axes via the acquisition unit 62. Thereafter, the loading control device 61 proceeds to the process of step S24.

[0060] In step S24, the loading control device 61 transmits a transmission instruction to the controller 16 of the pallet 1 via the acquisition unit 62, instructing it to calculate and transmit the pressure center of the load placed on the upper plate 11. Then, after receiving the pressure center of the load placed on the upper plate 11 from the controller 16 via the acquisition unit 62, the loading control device 61 proceeds to the process of step S25.

[0061] In step S25, the loading control device 61 inputs, via the analysis unit 63, the weight and center of gravity of the load gripped by the robot hand 55 detected in step S23 and the pressure center of the load placed on the upper plate 11 of the pallet 1 acquired in step S24 into the learned model stored in the model storage unit 65. Then, the loading control device 61 estimates the installation position output from the learned model as the installation position of the load gripped by the robot hand 55 on the upper plate 11 and proceeds to the process of step S26.

[0062] In step S26, after transmitting, via the output unit 64, a load installation instruction including the installation position of the load gripped by the robot hand 55 on the upper plate 11 estimated in step S25 to the robot controller 57, the loading control device 61 proceeds to the process of step S27. Thereby, the loading control device 61 can instruct the robot 51 of the installation position of the load and install the load on the upper plate 11.

[0063] In step S27, the loading control device 61 determines whether all the loads have been installed on the upper plate 11. If the loading control device 61 determines that not all the loads have been installed on the upper plate 11 (S27: NO), it executes the processes after step S21 again. On the other hand, if the loading control device 61 determines that all the loads have been installed on the upper plate 11 (S27: YES), it proceeds to the process of step S28.

[0064] In step S28, after the loading control device 61 transmits a horizontal instruction to instruct the controller 16 of the pallet 1 to bring the upper plate 11 closer to the horizontal via the output unit 64, the loading control process ends. As a result, since the pressure center of the upper plate 11 of the pallet 1 approaches the center position 11A of the upper plate 11, load collapse can be suppressed.

[0065] [Force sensor output process] Next, the force sensor output process executed by the robot controller 57 of the loading system 100 configured as described above will be described with reference to FIG. 12. FIG. 12 is a flowchart showing an example of the force sensor output process executed by the robot controller 57. Note that the robot controller 57 executes the force sensor output process at predetermined time intervals, for example, every about 0.1 seconds. The program shown as a flowchart in FIG. 12 is stored in advance in the ROM 572.

[0066] As shown in FIG. 12, in step S31, the robot controller 57 determines whether or not it has received a load gripping instruction instructing it to grip the load to be placed on the upper plate 11 from the loading control device 61. If the robot controller 57 determines that it has not received a load gripping instruction instructing it to grip the load to be placed on the upper plate 11 (S31: NO), the process proceeds to the process of step S33 described later. On the other hand, if the robot controller 57 determines that it has received a load gripping instruction instructing it to grip the load to be placed on the upper plate 11 (S31: YES), the process proceeds to the process of step S32.

[0067] In step S32, the robot controller 57 drives and controls the first joint motor 53A to the fourth joint motor 53D and the actuator 55A to grip the load to be placed on the upper plate 11 with the robot hand 55, lift it slightly, and then proceed to the process of step S33.

[0068] In step S33, the robot controller 57 determines whether it has received a transmission instruction from the loading control device 61 to transmit detection signals of the force components FX, FY, and FZ in the three-axis directions of the hand force sensor 56 and the moment components MX, MY, and MZ with the three axes of the X-axis, Y-axis, and Z-axis as the rotation axes.

[0069] And if the robot controller 57 determines that it has not received a transmission instruction from the loading control device 61 to transmit detection signals of the force components FX, FY, and FZ in the three-axis directions of the hand force sensor 56 and the moment components MX, MY, and MZ with the three axes of the X-axis, Y-axis, and Z-axis as the rotation axes (S33: NO), it proceeds to the process of step S35 described below.

[0070] On the other hand, if the robot controller 57 determines that it has received a transmission instruction from the loading control device 61 to transmit detection signals of the force components FX, FY, and FZ in the three-axis directions of the hand force sensor 56 and the moment components MX, MY, and MZ with the three axes of the X-axis, Y-axis, and Z-axis as the rotation axes (S33: YES), it proceeds to the process of step S34. In step S34, after the robot controller 57 transmits the detection signals of the force components FX, FY, and FZ in the three-axis directions of the hand force sensor 56 and the moment components MX, MY, and MZ with the three axes of the X-axis, Y-axis, and Z-axis as the rotation axes to the loading control device 61, it proceeds to the process of step S35.

[0071] In step S35, the robot controller 57 determines whether it has received a luggage placement instruction from the loading control device 61 that includes the placement position on the upper plate 11 of the luggage gripped by the robot hand 55. And if the robot controller 57 determines that it has not received a luggage placement instruction from the loading control device 61 that includes the placement position on the upper plate 11 of the luggage gripped by the robot hand 55 (S35: NO), it ends the force sensor output process.

[0072] On the other hand, when the robot controller 57 determines that it has received a load placement instruction including the placement position on the upper plate 11 of the load held by the robot hand 55 from the load placement control device 61 (S35: YES), the process proceeds to step S36. In step S36, after the robot controller 57 places the load held by the robot hand 55 at the placement position on the upper plate 11 included in the load placement instruction, the robot controller 57 moves the robot hand 55 to the initial position and ends the force sensor output process. Thereby, the robot controller 57 can place the load on the upper plate 11 so that the pressure center of the upper plate 11 of the pallet 1 approaches the center position 11A of the upper plate 11.

[0073] [Pressure center output process] Next, the pressure center process executed by the controller 16 of the pallet 1 of the loading system 100 configured as described above will be described with reference to FIG. 13. FIG. 13 is a flowchart showing an example of the pressure center output process executed by the controller 16 of the pallet 1. The controller 16 executes the pressure center output process at predetermined time intervals, for example, every about 0.1 second. The program shown as a flowchart in FIG. 13 is stored in advance in the ROM 162.

[0074] As shown in FIG. 13, in step S41, the controller 16 determines whether it has received a transmission instruction from the load placement control device 61 to calculate and transmit the pressure center of the load placed on the upper plate 11. If the controller 16 determines that it has not received a transmission instruction from the load placement control device 61 to calculate and transmit the pressure center of the load placed on the upper plate 11 (S41: NO), the process proceeds to step S44 described later. On the other hand, when the controller 16 determines that it has received a transmission instruction from the load placement control device 61 to calculate and transmit the pressure center of the load placed on the upper plate 11 (S41: YES), the process proceeds to step S42.

[0075] In step S42, the controller 16 detects the force components FX, FY, and FZ in the three-axis directions acting on each of the force sensors 13A to 13D by the load placed on the upper plate 11 of the pallet 1. Then, the controller 16 calculates the forces FA, FB, FC, and FD acting on each of the force sensors 13A to 13D from the force components FX, FY, and FZ in the three-axis directions of each of the force sensors 13A to 13D. Subsequently, the controller 16 calculates the position on the upper plate 11 where the sum F3 = FA + FB + FC + FD of the forces FA, FB, FC, and FD acts, and stores it in the storage unit 164 as the pressure center (the third pressure center) of the load placed on the upper plate 11. After that, the controller 16 proceeds to the process of step S43.

[0076] In step S43, the controller 16 reads out the pressure center of the load placed on the upper plate 11 from the storage unit 164, transmits the position information of this pressure center to the stacking control device 61, and then proceeds to the process of step S44.

[0077] In step S44, the controller 16 determines whether it has received a horizontal instruction from the stacking control device 61 to approach the upper plate 11 horizontally. And when the controller 16 determines that it has not received a horizontal instruction from the stacking control device 61 to approach the upper plate 11 horizontally (S44: NO), it ends the pressure center output process.

[0078] On the other hand, when the controller 16 determines that it has received a horizontal instruction from the stacking control device 61 to approach the upper plate 11 horizontally (S44: YES), it proceeds to the process of step S45.

[0079] In step S45, the controller 16 detects the force components FX, FY, and FZ in the three-axis directions acting on each of the force sensors 13A to 13D by the load placed on the upper plate 11 of the pallet 1. Then, the controller 16 calculates the forces FA, FB, FC, and FD acting on each of the force sensors 13A to 13D from the force components FX, FY, and FZ in the three-axis directions of each of the force sensors 13A to 13D.

[0080] Subsequently, the controller 16 calculates the position on the upper plate 11 where the sum of the forces FA, FB, FC, and FD, F4 = FA + FB + FC + FD, acts, and stores it in the storage unit 164 as the pressure center of the load placed on the upper plate 11. Then, the controller 16 drives each lifting mechanism 15A to 15D so that this pressure center is located within a predetermined range centered on the center position 11A of the upper plate 11 of the pallet 1, for example, within a circle with a radius of approximately 2 cm to 4 cm, to bring the upper plate 11 closer to being horizontal. After that, the controller 16 ends the pressure center output process. Thereby, it is possible to prevent the load placed on the upper plate 11 of the pallet 1 from collapsing.

[0081] As described in detail above, in the loading system 100 according to the second embodiment, the loading control device 61 sets the installation position of the load held by the robot hand 55 on the upper plate 11 based on the weight and center of gravity of the load held by the robot hand 55 and the pressure center of the upper plate 11 of the load placed on the upper plate 11. Thereby, the pressure center on the upper plate 11 can be brought closer to the center position 11A of the upper plate 11, and it is possible to prevent the load on the pallet 1 from collapsing.

[0082] Also, by installing the load held by the robot hand 55 at the installation position of the upper plate 11 estimated by the analysis unit 63 of the loading control device 61, the pressure center on the upper plate 11 of the pallet 1 approaches the center position 11A of the upper plate 11, so that it is possible to prevent the load on the pallet 1 from collapsing. Furthermore, the robot hand 55 and the robot arm 52 can be driven and controlled by the robot controller 57, and the processing of the loading control device 61 can be simplified.

[0083] [Modification Example 1] In the pallet 1 according to the first embodiment described above, four force sensors 13A to 13D and four lifting mechanisms 15A to 15D are provided, but three force sensors and three lifting mechanisms, or five or more force sensors and five or more lifting mechanisms may be provided.

[0084] For example, on the lower surface of the upper plate 11 of the pallet 1, force sensors 13A and 13B may be attached to both end corners of one side edge of the lower surface, and a force sensor 13C may be attached at a substantially central position of the other side edge facing this one side edge. Then, three elevating mechanisms 15A to 15C may be attached between the three force sensors 13A to 13C and the upper surface of the lower frame 12. Thereby, the controller 16 can acquire the pressure center of the load placed on the upper plate 11 based on the output signals of the three force sensors 13A to 13C. Further, the controller 16 can drive each of the motors 26A to 26C of the three elevating mechanisms 15A to 15C to bring the upper plate 11 closer to a horizontal state.

[0085] [Modification Example 2] For example, in the pallet 1 according to the above Embodiment 1, force sensors 13A to 13D may be attached to the four corners of the upper surface of the lower frame 12. Then, elevating mechanisms 15A to 15D may be attached between each of the force sensors 13A to 13D and the four corners of the lower surface of the upper plate 11. Thereby, the controller 16 can acquire the pressure center of the load placed on the upper plate 11 based on the output signals of each of the force sensors 13A to 13D. Further, the controller 16 can drive each of the motors 26A to 26D of the elevating mechanisms 15A to 15D to bring the upper plate 11 closer to a horizontal state.

[0086] [Modification Example 3] For example, in the pallet 1 according to the above Embodiment 1, the lower frame 12 may be a rectangular frame in plan view and may be composed of a cross-shaped bar spanned across substantially central portions of opposite side edges. Thereby, the weight of the pallet 1 can be reduced.

[0087] [Modification Example 4] For example, each of the force sensors 13A to 13D may be substantially circular in plan view.

[0088] [Modification Example 5] For example, in the pallet 1 according to the above-described Embodiment 1, plate-shaped rubbers having substantially the same size as the bottom plate portions 22 of the elevating mechanisms 15A to 15D and having a rectangular shape in plan view with a thickness of about 2 cm to 4 cm, for example, may be attached as cushioning materials to the four corners of the upper surface of the lower frame 12. Then, the bottom plate portions 22 of the elevating mechanisms 15A to 15D may be attached to the upper surfaces of cushioning materials such as plate-shaped rubbers. Thereby, when an impact force in a direction orthogonal to the vertical direction acts on each of the elevating mechanisms 15A to 15D, the impact force is weakened by the cushioning material such as the plate-shaped rubber, and damage to the lower frame 12 and each of the elevating mechanisms 15A to 15D can be suppressed.

[0089] 〔Supplementary Note〕 The present disclosure is not limited to the above-described embodiments and each modification, and various changes can be made within the scope indicated in the claims. Embodiments obtained by appropriately combining the technical means disclosed in the embodiments and each modification are also included in the technical scope of the present disclosure.

[0090] [Supplementary Note] The pallet according to the first aspect includes an upper plate on which a load is placed, a lower frame disposed opposite to the upper plate, at least three force sensors disposed on the lower surface of the upper plate or the upper surface of the lower frame, and at least three elevating mechanisms disposed between the upper plate and the lower frame via the force sensors and capable of elevating the upper plate with respect to the lower frame, and a controller that drives and controls the at least three elevating mechanisms based on output signals of the at least three force sensors.

[0091] According to the pallet of the first aspect, when the pallet with a load placed on the upper plate is tilted, the controller can drive and control the at least three elevating mechanisms based on the output signals of the at least three force sensors to bring the upper plate closer to a horizontal state. As a result, when the pallet is tilted, the controller can prevent the load from collapsing.

[0092] The pallet of the second aspect is the pallet of the first aspect, and the controller drives and controls at least three of the elevating mechanisms based on the output signals of at least three of the force sensors when the upper plate is horizontal and the current output signals of at least three of the force sensors so that the upper plate approaches being horizontal.

[0093] According to the pallet of the second aspect, the controller drives and controls at least three elevating mechanisms based on the output signals of at least three force sensors when the upper plate is horizontal and the current output signals, so as to bring the upper plate closer to being horizontal. Thereby, when the pallet is tilted, the controller can bring the upper plate closer to being horizontal and further prevent the load on the pallet from collapsing.

[0094] The loading system of the third aspect includes the pallet of the first aspect or the second aspect, a robot in which a robot hand is attached to the tip of a robot arm via a hand force sensor, and a loading control device that controls the robot to load a load onto the upper plate of the pallet. The loading control device has a setting unit that sets the installation position of the load held by the robot hand on the upper plate based on the output signal of the hand force sensor and the output signal of at least three of the force sensors or the controller, and controls the robot to install the load held by the robot hand at the installation position of the upper plate set by the setting unit.

[0095] According to the loading system of the third aspect, the loading control device sets the installation position of the load held by the robot hand on the upper plate based on the output signal of the hand force sensor and the output signal of at least three force sensors or the controller. Thereby, the center of pressure on the upper plate can be brought closer to the center position of the upper plate, and the load collapse of the pallet can be prevented.

[0096] The fourth aspect is the loading system of the third aspect, wherein the setting unit sets the installation position of the load held by the robot hand on the upper plate using a learned model generated by machine learning.

[0097] According to the loading system of the fourth aspect, the installation position of the load held by the robot hand is set using a learned model generated by machine learning. Thereby, the center of pressure on the upper plate can be made closer to the center position of the upper plate, and the collapse of the load on the pallet can be suppressed.

Description of Signs

[0098] 1: Pallet, 11: Upper plate, 12: Lower frame, 13A - 13D: Force - sensing sensor, 15A - 15D: Lifting mechanism, 16: Controller, 51: Robot, 52: Robot arm, 55: Robot hand, 56: Hand force - sensing sensor, 57: Robot controller, 61: Loading control device, 62: Acquisition unit, 63: Analysis unit, 66: Setting unit

Claims

1. An upper plate for placing a load, A lower frame disposed opposite to the upper plate, At least three force sensors disposed on the lower surface of the upper plate or the upper surface of the lower frame, At least three elevating mechanisms disposed between the upper plate and the lower frame via the force sensors and capable of raising and lowering the upper plate relative to the lower frame, A controller for driving and controlling at least three of the elevating mechanisms based on output signals of at least three of the force sensors, A pallet comprising the above.

2. The controller drives and controls at least three of the elevating mechanisms based on output signals of at least three of the force sensors when the upper plate is horizontal and current output signals of at least three of the force sensors so that the upper plate approaches horizontal, The pallet according to Claim 1.

3. The pallet according to Claim 1 or Claim 2, A robot in which a robot hand is attached to the tip of a robot arm via a hand force sensor, A loading control device for controlling the robot to load a load on the upper plate of the pallet, Comprising, The loading control device, Has a setting unit that sets an installation position of the load gripped by the robot hand on the upper plate based on an output signal of the hand force sensor and an output signal of at least three of the force sensors or the controller, A loading system that controls the robot to install the load gripped by the robot hand at the installation position of the upper plate set by the setting unit.

4. The setting unit sets an installation position of the load gripped by the robot hand on the upper plate using a learned model generated by machine learning, The loading system according to Claim 3.

Images