Tray and stacking system

Abstract

The invention provides a tray and a stacking system. The tray can restrain scattering of goods under the condition that the tray is inclined. A tray (1) is provided with: an upper plate (11) on which goods are placed; a lower frame (12) disposed so as to face the upper plate (11); at least three force sensors (13A-13D) which are arranged on the lower surface of the upper plate (11) or the upper surface of the lower frame (12); at least three lifting mechanisms (15A-15D) which are disposed between the upper plate (11) and the lower frame (12) by means of force sensors (13A-13D) and which are capable of lifting the upper plate relative to the lower frame; and a controller (16) that drives and controls the at least three lifting mechanisms (15A-15D) on the basis of output signals from the at least three force sensors (13A-13D).

Description

Technical Field

[0001] The present invention relates to a pallet and a stacking system. Background Art

[0002] Patent Document 1 describes a forklift pallet having an insertion hole for inserting a fork extending forward of a forklift so as to penetrate the forklift pallet, and a mark recognizable by a driver formed near an entrance of the insertion hole.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Utility Model Publication No. 3232641 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] When loading cargo onto such a forklift pallet, if the weight of the cargo and the center of gravity of the entire pallet are not considered, the center of gravity of the entire pallet may be offset. As a result, the cargo may be scattered when transported by a forklift. In addition, when a truck or other vehicle carrying a pallet travels on a slope, the cargo box may tilt and the cargo may be scattered.

[0008] One aspect of the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a pallet and a stacking system capable of suppressing the scattering of cargo when the pallet is tilted.

[0009] Solutions for solving problems

[0010] In order to solve the above-mentioned problem, a pallet involved in one embodiment of the present invention comprises: an upper plate, which is used to carry goods; a lower frame, which is arranged opposite to the upper plate; at least three force sensors, which are arranged on the lower surface of the upper plate or the upper surface of the lower frame; at least three lifting mechanisms, which are arranged between the upper plate and the lower frame by the force sensors and can lift the upper plate relative to the lower frame; and a controller, which drives and controls the at least three lifting mechanisms based on output signals of the at least three force sensors.

[0011] Effects of the Invention

[0012] According to one embodiment of the present invention, when a pallet with goods on its upper plate is tilted, a controller can drive and control at least three lifting mechanisms based on output signals of at least three force sensors to make the upper plate close to a horizontal state. As a result, the controller can prevent the goods from scattering when the pallet is tilted. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a perspective view showing an example of a schematic structure of a tray according to the first embodiment.

[0014] Figure 2 This is a plan view showing an example of a schematic structure of a tray according to the first embodiment.

[0015] Figure 3 It is a perspective view showing an example of a lifting mechanism.

[0016] Figure 4 This is a block diagram showing an example of the electrical configuration of the tray according to the first embodiment.

[0017] Figure 5 This is a flowchart showing an example of the upper plate lifting control process executed by the controller.

[0018] Figure 6 This is a front view showing an example of the pressure center when the pallet is in a horizontal state.

[0019] Figure 7 This is a front view showing an example of the pressure center when the pallet is tilted.

[0020] Figure 8 This is a diagram schematically showing an example of the movement of a pallet placed on a cargo box of a truck.

[0021] Fig. 9 This is an explanatory diagram for explaining the schematic configuration of a stacking system according to the second embodiment.

[0022] Fig.10 This is a block diagram showing an example of the electrical configuration of the stacking system according to the second embodiment.

[0023] Fig.11 This is a flowchart showing an example of a stack control process executed by the stack control device according to the second embodiment.

[0024] Fig.12 This is a flowchart showing an example of force sensor output processing executed by the robot controller involved in the second embodiment.

[0025] Fig.13 This is a flowchart showing an example of the pressure center output process executed by the controller of the pallet according to the second embodiment. DETAILED DESCRIPTION

[0026] Embodiment 1 and Embodiment 2 in which the present invention is embodied will be described in detail below with reference to the drawings. The same or equivalent components and members shown in the drawings are denoted by the same reference numerals, and duplicate descriptions are omitted as appropriate.

[0027] [Implementation Method 1]

[0028] [Schematic Structure of Tray 1]

[0029] First, based on Figure 1 and Figure 2 A schematic structure of a tray 1 according to Embodiment 1 of the present disclosure will be described. Figure 1 This is a perspective view showing an example of a schematic structure of the tray 1 according to the first embodiment. Figure 2 1 is a top view showing an example of the schematic structure of the tray 1 involved in the first embodiment. Figure 1 and Figure 2 As shown, the tray 1 includes an upper plate 11 , a lower frame 12 , four force sensors 13A to 13D, four lifting mechanisms 15A to 15D, a controller 16 , and a battery 17 .

[0030] The upper plate 11 is a wooden or resin plate, and is formed into a rectangular flat plate in a plan view. Goods are placed on the upper surface of the upper plate 11. Force sensors 13A to 13D having a rectangular shape in a plan view and a predetermined thickness are mounted at the four corners of the lower surface of the upper plate 11.

[0031] The lower frame 12 is a wooden or resin plate, formed in a flat plate shape, and formed in a rectangular shape of approximately the same size as the upper plate 11 when viewed from above. The lower frame 12 is arranged on the lower side of the upper plate 11 facing the upper plate 11. Lifting mechanisms 15A to 15D that are rectangular in a plan view are installed at the four corners of the upper surface of the lower frame 12, and the upper ends of the lifting mechanisms 15A to 15D can move in the up and down directions. In addition, the lower ends of the force sensors 13A to 13D of the upper plate 11 are installed on the upper ends of the lifting mechanisms 15A to 15D, and the lower frame 12 is installed on the lower surface of the upper plate 11 via the force sensors 13A to 13D and the lifting mechanisms 15A to 15D.

[0032] Each force sensor 13A to 13D is a three-axis force sensor that detects force components FX, FY, and FZ in three axial directions, namely, the X-axis, the Y-axis, and the Z-axis, of a force sensor coordinate system whose axial direction is set to the Z-axis direction. Each force sensor 13A to 13D is mounted on the lower surface of the upper plate 11 in such a manner that the Z-axis direction is set to the vertical direction. In addition, the force sensor 13 may also be a six-axis force sensor that detects force components FX, FY, and FZ in three axial directions, namely, the X-axis, the Y-axis, and the Z-axis, of a force sensor coordinate system whose axial direction is set to the Z-axis direction, and moment components MX, MY, and MZ with the three axes of the X-axis, the Y-axis, and the Z-axis as rotation axes.

[0033] [Schematic Structure of Lifting Mechanisms 15A to 15D]

[0034] based on Figure 3The schematic structure of the lifting mechanisms 15A to 15D will be described. Figure 3 1 is a perspective view showing an example of the lifting mechanism 15A. In addition, the lifting mechanisms 15A to 15D have the same structure, so the lifting mechanism 15A will be described. Figure 3 As shown, the lifting mechanism 15A includes: a top plate portion 21, which is flat and rectangular in a plan view; a bottom plate portion 22, which is flat and rectangular in a plan view; a pair of link mechanisms 23A and 23B, which are arranged facing each other; a lead screw 25; and a motor 26A that drives the lead screw 25 to rotate. In addition, each lifting mechanism 15A to 15D includes a motor 26A to 26D that drives the respective lead screws 25 to rotate. The motors 26A to 26D are composed of a stepping motor, a DC servo motor, or the like.

[0035] The upper surface of the top plate 21 is mounted on the lower end surface of the force sensor 13A by means of fastening screws, etc., and is mounted on the lower surface of the upper plate 11 by means of the force sensor 13A. Upper mounting ribs 27A and 27B protruding in a rib-like manner over the entire width of the end are provided at both side edges of the top plate 21 facing the upper end portions of the pair of link mechanisms 23A and 23B. In addition, the lower surface of the bottom plate 22 is placed on the upper surface of the lower frame 12 and is mounted on the upper surface of the lower frame 12 by means of fastening screws, etc. Lower mounting ribs 28A and 28B protruding in a rib-like manner over the entire width of the end are provided at both side edges of the bottom plate 22 facing the lower end portions of the pair of link mechanisms 23A and 23B.

[0036] The pair of link mechanisms 23A and 23B are four-link structures in which a pair of links are stacked in two layers in the vertical direction in an X-shaped structure and connected in a manner that the entirety can be telescopically displaced. The upper end portion of the upper X-shaped structure on the motor 26A side is rotatably fixed to the upper mounting ribs 27A and 27B via a shaft support shaft 29A provided between the pair of link mechanisms 23A and 23B. The upper end portion of the upper X-shaped structure on the side opposite to the motor 26A is engaged with the upper mounting ribs 27A and 27B via a shaft support shaft 29B provided between the pair of link mechanisms 23A and 23B in a manner that is parallel to and freely slidable with respect to the top plate portion 21.

[0037] The lower ends of the pair of connecting rods of the upper X-shaped structure and the upper ends of the pair of connecting rods of the lower X-shaped structure are connected in a manner that allows them to rotate using the rotating shaft support members 31 and 32 provided between the pair of connecting rod mechanisms 23A and 23B as a fulcrum. The lower end of the lower end of the X-shaped structure of the lower layer, which is close to the motor 26A, is rotatably fixed to the lower mounting ribs 28A and 28B via the shaft support shaft 29C provided between the pair of connecting rod mechanisms 23A and 23B. The lower end of the lower end of the X-shaped structure of the lower layer, which is close to the side opposite to the motor 26A, is engaged with the lower mounting ribs 28A and 28B via the shaft support shaft 29D provided between the pair of connecting rod mechanisms 23A and 23B in a manner that allows them to slide freely in parallel with the bottom plate 22.

[0038] The lead screw 25 penetrates the threaded hole formed in the rotating shaft support member 32 on the motor 26A side in a manner of being screwed into the threaded hole, and the front end of the lead screw 25 is rotatably fixed to the rotating shaft support member 31 arranged opposite to the rotating shaft support member 32. In addition, the motor 26A is connected to the rear end of the lead screw 25 in a manner that allows the lead screw 25 to rotate.

[0039] Therefore, in the lifting mechanism 15A configured as above, when the lead screw 25 is rotated, for example, in the clockwise direction by 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 21 rises. As a result, the upper plate 11 rises with the help of the force sensor 13A. On the other hand, when the lead screw 25 is rotated, for example, in the counterclockwise direction by the motor 26A, the rotation shaft support members 31 and 32 separate from each other, the pair of link mechanisms 23A and 23B contract, and the top plate 21 descends. As a result, the upper plate 11 descends with the help of the force sensor 13A.

[0040] In addition, if Figure 1 As shown, a start switch 16A as an example of an operation unit is provided in the controller 16. 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.

[0041] [Electrical structure of tray 1]

[0042] Next, based on Figure 4 The electrical structure of the tray 1 will be described. Figure 4 1 is a block diagram showing an example of the electrical structure of the tray 1. Figure 4 As shown, the tray 1 includes a controller 16, a start switch 16A, force sensors 13A to 13D, and motors 26A to 26D.

[0043] 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, a HDD (Hard Disk Drive), an SSD (Solid State Drive), etc. The CPU 161 performs various calculations based on various programs and various parameters stored in the ROM 162. The RAM 163 temporarily stores the calculation results and data of the CPU 161. The storage unit 164 stores data such as the pressure center described later.

[0044] The controller 16 is electrically connected to the start switch 16A, the force sensors 13A to 13D, and the motors 26A to 26D. The start switch 16A is composed of a push button switch, and by pressing the push button switch, for example, Figure 5 The controller 16 performs the upper plate lifting control process shown in the figure. In addition, the controller 16 stores the output signals input from the force sensors 13A to 13D in the RAM 163. In addition, the controller 16 performs rotational drive control on the motors 26A to 26D to perform lifting control on the lifting mechanisms 15A to 15D.

[0045] [Upper plate lifting control processing]

[0046] Next, based on Figures 5 to 8 An example of the upper plate lifting and lowering control process executed by the controller 16 of the tray 1 configured as described above will be described. Figure 5 1 is a flowchart showing an example of the upper board lifting and lowering control process executed by the controller 16 . Figure 6 This is a front view showing an example of the pressure center when the tray 1 is in a horizontal state. Figure 7 This is a front view showing an example of the pressure center when the tray 1 is tilted. Figure 8 This is a diagram schematically showing an example of the movement of the pallet 1 placed on the cargo box 38A of the truck 38 .

[0047] like Figure 5 As shown, in step S11, the controller 16 determines whether the start switch 16A is pressed and turned on. Then, when the controller 16 determines that the start switch 16A is not pressed and the start switch 16A is turned off (S11: "No"), the upper plate lifting control process is terminated. On the other hand, when the controller 16 determines that the start switch 16A is pressed and turned on (S11: "Yes"), the process proceeds to step S12.

[0048] In step S12, the controller 16 detects the three axial force components FX, FY, and FZ (output signals when the pallet 1 is horizontal) acting on each force sensor 13A to 13D from the cargo placed on the pallet 1 in a horizontal state, that is, the upper plate 11 of the horizontally placed pallet 1. Then, the controller 16 calculates the forces FA, FB, FC, and FD acting on each force sensor 13A to 13D based on the three axial force components FX, FY, and FZ of each force sensor 13A to 13D. Next, the controller 16 calculates the acting position of the sum F1 of each force FA, FB, FC, and FD = FA+FB+FC+FD on the upper plate 11, and stores it in the storage unit 164 as the first pressure center (COP: Center of Pressure) 36 of the cargo placed on the upper plate 11. Thereafter, the controller 16 enters the processing of step S13.

[0049] For example Figure 6 As shown, the controller 16 detects the three axial force components FX, FY, and FZ acting on each force sensor 13A to 13D by the cargo 35 placed on the upper plate 11 of the horizontally placed pallet 1. Then, the controller 16 calculates the forces FA, FB, FC, and FD acting on each force sensor 13A to 13D based on the three axial force components FX, FY, and FZ of each force sensor 13A to 13D.

[0050] Next, the controller 16 calculates the sum F1=FA+FB+FC+FD of the forces FA, FB, FC, and FD acting on the upper plate 11, and stores it in the storage unit 164 as the first pressure center 36 of the cargo 35 placed on the upper plate 11. Figure 2 and Figure 6 As shown, when the center of gravity G1 of the cargo 35 is located at the intersection of the diagonal lines of the upper plate 11 , that is, on the vertical line passing through 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 .

[0051] like Figure 5 As shown, in step S13, the controller 16 determines whether the current time is a timing that has passed a predetermined time, for example, about 1 second to 5 seconds, after the start of the process in step S13. Then, if the controller 16 determines that the current time is not a timing that has passed a predetermined time (S13: "No"), the process of step S13 is executed again. On the other hand, if the controller 16 determines that the current time is a timing that has passed a predetermined time (S13: "Yes"), the process of step S14 is entered.

[0052] In step S14, the controller 16 detects the three axial force components FX, FY, and FZ (current output signals) acting on each force sensor 13A to 13D by the goods 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 force sensor 13A to 13D based on the three axial force components FX, FY, and FZ of each force sensor 13A to 13D. Next, the controller 16 calculates the sum F2 = FA + FB + FC + FD of each force FA, FB, FC, and FD at the acting position on the upper plate 11, and stores it in the storage unit 164 as the second pressure center (COP: Center of Pressure) 37 of the goods placed on the upper plate 11. Thereafter, the controller 16 enters the processing of step S15.

[0053] For example Figure 7 As shown, the controller 16 detects the three axial force components FX, FY, and FZ acting on each force sensor 13A to 13D by the cargo 35 placed on the upper plate 11 of the tilted pallet 1. Then, the controller 16 calculates the forces FA, FB, FC, and FD acting on each force sensor 13A to 13D based on the three axial force components FX, FY, and FZ of each force sensor 13A to 13D.

[0054] Next, the controller 16 calculates the sum F2=FA+FB+FC+FD of the forces FA, FB, FC, and FD acting on the upper plate 11, and stores it in the storage unit 164 as the second pressure center 37 of the cargo 35 placed on the upper plate 11. Figure 2 and Figure 7 As shown, when the center of gravity G1 of the cargo 35 is located at the intersection of the diagonals of the upper plate 11, that is, on the vertical line passing through the center position 11A of the upper plate 11, the second pressure center 37 is located at a distance L1 away from the center position 11A of the upper plate 11.

[0055] like Figure 5 As shown, 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 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. Figure 2 and Figure 7 As shown, when the center of gravity G1 of the cargo 35 is located on a vertical 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 a circle 39 centered on the center position 11A of the upper plate 11. In addition, the prescribed range centered on the first pressure center 36 is not limited to a circle, but may be a polygon such as a quadrilateral, pentagon, or hexagon.

[0056] Then, when the controller 16 determines that the second pressure center 37 is within the prescribed range centered on the first pressure center 36 (S15: "Yes"), the controller 16 does not change the inclination of the upper plate 11 and proceeds to the processing of step S17 described later. On the other hand, when the controller 16 determines that the second pressure center 37 is not within the prescribed range centered on the first pressure center 36 (S15: "No"), the controller 16 proceeds to the processing of step S16 to make the inclination of the upper plate 11 of the tray 1 close to the horizontal.

[0057] In step S16, the controller 16 drives each lifting mechanism 15A to 15D so that the second pressure center 37 is located within a specified range centered on the first pressure center 36, so that the upper plate 11 is close to horizontal, and then enters the process of step S17. Specifically, the controller 16 drives each motor 26A to 26D of each lifting mechanism 15A to 15D to rotate, and drives each lead screw 25 to rotate in the clockwise direction or counterclockwise direction, so as to lift and lower the corner of the upper plate 11 through each force sensor 13A to 13D. In this way, the tilt of the goods on the upper plate 11 of the pallet 1 can be eliminated to prevent the goods from scattering.

[0058] For example Figure 8 As shown, when a truck 38 carrying a pallet 1 carrying cargo 41 in a cargo box 38A is traveling on a slope, stopped on a slope, or parked, the controller 16 drives the lifting mechanisms 15A to 15D to make the upper plate 11 close to horizontal. In addition, for the pallet 1 carried in the cargo box 38A of the truck 38, power may be supplied to the motors 26A to 26D of the lifting mechanisms 15A to 15D from a battery (not shown) carried in the truck 38 instead of the battery 17.

[0059] Specifically, the controller 16 drives the motors 26A and 26B of the lifting mechanisms 15A and 15B on the front side (the side in the direction of travel of the truck 38) to rotate, and drives the lead screws 25 to rotate in the counterclockwise direction. Thus, the controller 16 lowers the two corners on the front side of the upper plate 11 via the force sensors 13A and 13B. In addition, the controller 16 drives the motors 26C and 26D of the lifting mechanisms 15C and 15D to rotate, and drives the lead screws 25 to rotate in the clockwise direction. Thus, the controller 16 raises the two corners on the rear side of the upper plate 11 (the side opposite to the direction of travel of the truck 38) via the force sensors 13C and 13D, and makes the upper plate 11 close to horizontal.

[0060] like Figure 5As shown, in step S17, the controller 16 determines whether the start switch 16A is pressed and turned off. Then, when the controller 16 determines that the start switch 16A is not pressed and the start switch 16A is turned on (S17: "No"), the controller 16 executes the processing of step S13 and thereafter again. On the other hand, when the controller 16 determines that the start switch 16A is pressed and turned off (S17: "Yes"), the upper plate lifting control processing ends.

[0061] As described in detail above, in the pallet 1 involved in Embodiment 1, the controller 16 calculates the first pressure center 36 on the upper plate 11 of the pallet 1 in the horizontal state based on the output signals of the force sensors 13A to 13D. Furthermore, 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 force sensors 13A to 13D every predetermined time.

[0062] Then, when it is determined that the second pressure center 37 is not within the prescribed range from the first pressure center 36, the controller 16 drives and controls the motors 26A to 26D of the lifting mechanisms 15A to 15D so that the second pressure center 37 is within the prescribed range from the first pressure center 36. Thus, the controller 16 can make the upper plate 11 close to the horizontal state, thereby preventing the cargo on the pallet 1 from scattering.

[0063] [Implementation Method 2]

[0064] [Schematic Structure of Stacking System 100]

[0065] Next, based on Fig. 9 A stacking system 100 according to a second embodiment of the present disclosure will be described. Fig. 9 This is an explanatory diagram for explaining a schematic configuration of a stacking 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 description will not be repeated.

[0066] like Fig. 9 As shown, the stacking system 100 includes the tray 1 involved in Embodiment 1, a robot 51, and a stacking 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 a multi-joint arm including a plurality of arms 52A. The five arms 52A of the robot arm 52 are connected by four joints 52B.

[0067] 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 moving the joint 52B. However, the number of arms 52A included in the robot 52 is not limited to five, and the number of joints 52B connecting the arms 52A is not limited to four.

[0068] The robot 55 is configured to hold the cargo by two claws 58. Fig.10 The actuator 55A shown opens and closes the two claws 58. The robot 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 robot 55 so that the position and posture can be changed.

[0069] The hand force sensor 56 detects the direction and magnitude of the force and torque acting on the hand. The hand force sensor 56 is a six-axis force sensor that detects force components FX, FY, and FZ in the three axial directions of the X-axis, Y-axis, and Z-axis of the force sensor coordinate system with the axial direction set as the Z-axis direction, and torque components MX, MY, and MZ with the three axes of the X-axis, Y-axis, and Z-axis as the rotation axes. The hand force sensor 56 is coaxially arranged with the robot 55.

[0070] Therefore, the hand force sensor 56 detects force components FX, FY, and FZ in the three axial directions of the X-axis, Y-axis, and Z-axis, and moment components MX, MY, and MZ with the three axes of rotation being the X-axis, Y-axis, and Z-axis. Hereinafter, FX, FY, FZ, MX, MY, and MZ are also recorded as force components or simply as detection values. The hand force sensor 56 outputs a signal related to the detection value to the robot controller 57.

[0071] [Electrical Structure of Robot Controller 57]

[0072] Next, based on Fig.10 The electrical structure of the robot controller 57 will be described. Fig.10 1 is a block diagram showing an example of the electrical structure of the stacking system 100. Fig.10 As shown, the robot controller 57 is composed of, for example, a CPU (Central Processing Unit) 571, a ROM (Read Only Memory) 572, and a RAM (Random Access Memory) 573. The CPU 571 performs various calculations based on various programs and various parameters stored in the ROM 572. The RAM 573 temporarily stores the calculation results and data of the CPU 571.

[0073] The robot controller 57 is electrically connected to the hand force sensor 56, the actuator 55A for opening and closing the two claws 58 of the robot hand 55, and the first to fourth joint motors 53A to 53D. The robot controller 57 is configured to communicate with the stack control device 61 by wire or wirelessly.

[0074] Furthermore, when the robot controller 57 receives a transmission request instruction from the stack control device 61, it transmits the detection signal of the hand force sensor 56 to the stack control device 61. In addition, when the robot controller 57 receives various operation instructions from the stack control device 61, it drives and controls the actuator 55A and the first joint motor 53A to the fourth joint motor 53D according to the programs corresponding to the various operation instructions stored in the ROM 572.

[0075] [Electrical Structure of Stack Control Device 61]

[0076] The stacking control device 61 is configured to communicate between the controller 16 of the pallet 1 and the robot controller 57 by wire or wireless. In addition, the stacking control device 61, the controller 16, and the robot controller 57 may be connected to a network such as the Internet or a LAN. Furthermore, the stacking control device 61 may communicate between the controller 16 and the robot controller 57 via a network.

[0077] The stacking control device 61 sets the placement position of the cargo held by the robot 55 on the upper plate 11 based on the pressure center (third pressure center) of the cargo placed on the upper plate 11 of the pallet 1 and the weight and center of gravity of the cargo held by the robot 55. Then, the stacking control device 61 controls the robot 51 to place the cargo at the placement position on the upper plate 11.

[0078] based on Fig.10 The electrical structure of the stack control device 61 is described below. Fig.10 As shown, the stacking 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 placement position of the goods.

[0079] The acquisition unit 62 requests the controller 16 of the pallet 1 to calculate and transmit the pressure center of the cargo placed on the upper plate 11. The acquisition unit 62 acquires the pressure center of the cargo placed on the upper plate 11 from the controller 16. In addition, the acquisition unit 62 receives detection signals of the force components FX, FY, and FZ in the three axial directions of the hand force sensor 56 and the torque components MX, MY, and MZ with the three axes of rotation, the X axis, the Y axis, and the Z axis, from the robot controller 57. The acquisition unit 62 acquires the weight and the center of gravity of the cargo held by the robot 55 based on the force components FX, FY, and FZ in the three axial directions of the hand force sensor 56 and the torque components MX, MY, and MZ with the three axes of rotation, the X axis, the Y axis, and the Z axis.

[0080] The analysis unit 63 inputs the weight and center of gravity of the cargo held by the robot 55 and the pressure center of the cargo placed on the upper plate 11 of the pallet 1 acquired by the acquisition unit 62 to the learned model stored in the model storage unit 65, and estimates the placement position of the cargo on the upper plate 11. The output unit 64 sends the placement position of the cargo on the upper plate 11 estimated by the analysis unit 63 to the robot controller 57 as the placement position of the cargo held by the robot 55 on the upper plate 11, and instructs the robot controller 57 to place the cargo on the upper plate 11. In addition, the output unit 64 outputs various request instructions to the robot controller 57.

[0081] 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 the following data as teaching data: the weight and center of gravity of the cargo held by the robot 55; the pressure center on the upper plate 11 of the pallet 1; and the setting position of the cargo held by the robot 55 on the upper plate 11 so that 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 in the following manner: when the weight and center of gravity of the cargo held by the robot 55 and the pressure center on the upper plate 11 of the pallet 1 are input, the setting position of the cargo held by the robot 55 on the upper plate 11 is output so that the position of the pressure center of the upper plate 11 approaches the center position 11A of the upper plate 11.

[0082] [Stack control processing]

[0083] Next, based on Fig.11 The stacking control process executed by the stacking control device 61 of the stacking system 100 configured as described above to place articles on the upper plate 11 of the pallet 1 by the robot 51 will be described. Fig.11 1 is a flowchart showing an example of the stacking control process executed by the stacking control device 61. In addition, when the stacking control device 61 receives a stacking instruction from the user to stack the goods on the upper plate 11, it executes Fig.11The stack control process is shown. Fig.11 The program shown in the flowchart is stored in advance in a ROM (not shown).

[0084] like Fig.11 As shown, in step S21, the stacking control device 61 outputs a cargo holding instruction to the robot controller 57 via the output unit 64 to hold the cargo placed on the upper plate 11, and then enters the process of step S22. Thus, the stacking control device 61 can instruct the robot 51 to hold the cargo placed on the upper plate 11 using the manipulator 55.

[0085] In step S22, the stack control device 61 instructs the robot controller 57 to transmit detection signals of the force components FX, FY, and FZ in the three axial directions of the hand force sensor 56 and the moment components MX, MY, and MZ with the three axes of the X-axis, the Y-axis, and the Z-axis as the rotation axes, via the output unit 64. Then, after acquiring the force components FX, FY, and FZ in the three axial directions of the hand force sensor 56 and the moment components MX, MY, and MZ with the three axes of the X-axis, the Y-axis, and the Z-axis as the rotation axes via the acquisition unit 62, the stack control device 61 proceeds to the processing of step S23.

[0086] In step S23, the stacking control device 61 detects the weight and center of gravity of the cargo held by the robot 55 based on the force components FX, FY, and FZ in the three axes and the moment components MX, MY, and MZ about the three axes of rotation, namely, the X-axis, the Y-axis, and the Z-axis, of the hand force sensor 56 acquired by the acquisition unit 62. Thereafter, the stacking control device 61 proceeds to the processing of step S24.

[0087] In step S24, the stacking control device 61 sends a transmission instruction to the controller 16 of the pallet 1 via the acquisition unit 62, instructing the calculation and transmission of the pressure center of the cargo placed on the upper plate 11. Then, after receiving the pressure center of the cargo placed on the upper plate 11 from the controller 16 via the acquisition unit 62, the stacking control device 61 proceeds to the processing of step S25.

[0088] In step S25, the stacking control device 61 inputs the weight and center of gravity of the cargo held by the robot 55 detected in step S23 and the pressure center of the cargo placed on the upper plate 11 of the pallet 1 acquired in step S24 to the learned model stored in the model storage unit 65 via the analysis unit 63. Then, the stacking control device 61 estimates the setting position output from the learned model as the setting position of the cargo held by the robot 55 on the upper plate 11, and proceeds to step S26.

[0089] In step S26, the stacking control device 61 sends the cargo placement instruction including the placement position of the cargo held by the robot 55 on the upper plate 11 estimated in step S25 to the robot controller 57 via the output unit 64, and then enters the process of step S27. Thus, the stacking control device 61 can instruct the robot 51 on the placement position of the cargo so that the robot 51 places the cargo on the upper plate 11.

[0090] In step S27, the stacking control device 61 determines whether all the goods have been placed on the upper plate 11. Then, if the stacking control device 61 determines that all the goods have not been placed on the upper plate 11 (S27: "No"), the stacking control device 61 executes the processing of step S21 and thereafter again. On the other hand, if the stacking control device 61 determines that all the goods have been placed on the upper plate 11 (S27: "Yes"), the processing proceeds to step S28.

[0091] In step S28, the stacking control device 61 ends the stacking control process after sending a level instruction to the controller 16 of the pallet 1 via the output unit 64 to instruct the upper plate 11 to approach the horizontal position. As a result, the pressure center of the upper plate 11 of the pallet 1 approaches the center position 11A of the upper plate 11, thereby preventing the goods from scattering.

[0092] [Force sensor output processing]

[0093] Next, based on Fig.12 The force sensor output process executed by the robot controller 57 of the stacking system 100 configured as described above will be described. Fig.12 2 is a flowchart showing an example of the force sensor output process executed by the robot controller 57. In addition, the robot controller 57 executes the force sensor output process at a predetermined time interval, for example, at approximately 0.1 second intervals. Fig.12 The program shown by the flowchart in FIG. 5 is stored in the ROM 572 in advance.

[0094] like Fig.12 As shown, in step S31, the robot controller 57 determines whether a gripping instruction for gripping the goods placed on the upper plate 11 is received from the stacking control device 61. Then, if the robot controller 57 determines that a gripping instruction for gripping the goods placed on the upper plate 11 is not received (S31: No), the robot controller 57 proceeds to the processing of step S33 described later. On the other hand, if the robot controller 57 determines that a gripping instruction for gripping the goods placed on the upper plate 11 is received (S31: Yes), the robot controller 57 proceeds to the processing of step S32.

[0095] In step S32 , the robot controller 57 drives and controls the first to fourth joint motors 53A to 53D and the actuator 55A to grip the cargo placed on the upper plate 11 with the robot hand 55 and slightly lift it, and then the process proceeds to step S33 .

[0096] In step S33, the robot controller 57 determines whether it has received a sending instruction from the stacking control device 61 to send detection signals of the three axial force components FX, FY, FZ of the hand force sensor 56 and the torque components MX, MY, MZ with the three axes of rotation, X-axis, Y-axis and Z-axis, as well as the detection signals.

[0097] Then, when the robot controller 57 determines that it has not received an instruction to send detection signals of the three axial force components FX, FY, FZ of the hand force sensor 56 and the torque components MX, MY, MZ with the X-axis, Y-axis, and Z-axis as rotation axes (S33: "No"), it enters the processing of step S35 described later.

[0098] On the other hand, when the robot controller 57 determines that it has received a transmission instruction to transmit the detection signals of the force components FX, FY, FZ in the three axial directions of the hand force sensor 56 and the torque components MX, MY, MZ with the three axes of the X-axis, Y-axis, and Z-axis as the rotation axes from the stack control device 61 (S33: Yes), the robot controller 57 proceeds to the processing of step S34. In step S34, after the robot controller 57 transmits the detection signals of the force components FX, FY, FZ in the three axial directions of the hand force sensor 56 and the torque components MX, MY, MZ with the three axes of the X-axis, Y-axis, and Z-axis as the rotation axes to the stack control device 61, the robot controller 57 proceeds to the processing of step S35.

[0099] In step S35, the robot controller 57 determines whether a cargo placement instruction including the placement position of the cargo held by the robot 55 on the upper plate 11 is received from the stacking control device 61. Then, if the robot controller 57 determines that a cargo placement instruction including the placement position of the cargo held by the robot 55 on the upper plate 11 is not received from the stacking control device 61 (S35: No), the force sensor output processing is terminated.

[0100] On the other hand, when the robot controller 57 determines that it has received a cargo placement instruction including the placement position of the cargo held by the robot 55 on the upper plate 11 from the stacking control device 61 (S35: Yes), the robot controller 57 proceeds to the process of step S36. In step S36, after placing the cargo held by the robot 55 at the placement position on the upper plate 11 included in the cargo placement instruction, the robot controller 57 moves the robot 55 to the initial position and ends the force sensor output process. Thus, the robot controller 57 can place the cargo on the upper plate 11 in such a way that the pressure center of the upper plate 11 of the pallet 1 approaches the center position 11A of the upper plate 11.

[0101] [Pressure center output processing]

[0102] Next, based on Fig.13 The pressure center output process executed by the controller 16 of the pallet 1 in the stacking system 100 configured as described above will be described. Fig.13 1 is a flowchart showing an example of the pressure center output process executed by the controller 16 of the tray 1. In addition, the controller 16 executes the pressure center output process at a predetermined time interval, for example, at approximately 0.1 second intervals. Fig.13 The program shown in the flowchart is stored in the ROM 162 in advance.

[0103] like Fig.13 As shown, in step S41, the controller 16 determines whether a transmission instruction for calculating and transmitting the pressure center of the cargo placed on the upper plate 11 is received from the stacking control device 61. Then, if the controller 16 determines that a transmission instruction for calculating and transmitting the pressure center of the cargo placed on the upper plate 11 is not received from the stacking control device 61 (S41: "No"), the controller 16 proceeds to the processing of step S44 described later. On the other hand, if the controller 16 determines that a transmission instruction for calculating and transmitting the pressure center of the cargo placed on the upper plate 11 is received from the stacking control device 61 (S41: "Yes"), the controller 16 proceeds to the processing of step S42.

[0104] In step S42, the controller 16 detects the three axial force components FX, FY, and FZ acting on each force sensor 13A to 13D by the goods 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 force sensor 13A to 13D based on the three axial force components FX, FY, and FZ of each force sensor 13A to 13D. Next, the controller 16 calculates the sum F3 = FA + FB + FC + FD of each force FA, FB, FC, and FD at the acting position on the upper plate 11, and stores it in the storage unit 164 as the pressure center (third pressure center) of the goods placed on the upper plate 11. Thereafter, the controller 16 enters the processing of step S43.

[0105] In step S43 , the controller 16 reads the pressure center of the cargo placed on the upper plate 11 from the storage unit 164 and transmits the position information of the pressure center to the stacking control device 61 , and then proceeds to step S44 .

[0106] In step S44, the controller 16 determines whether a horizontal instruction for instructing the upper plate 11 to be close to horizontal is received from the stack control device 61. Then, if the controller 16 determines that a horizontal instruction for instructing the upper plate 11 to be close to horizontal is not received from the stack control device 61 (S44: No), the pressure center output process ends.

[0107] On the other hand, when the controller 16 determines that the horizontal instruction to make the upper plate 11 close to horizontal is received from the stack control device 61 (S44: Yes), the controller 16 proceeds to the process of step S45.

[0108] In step S45, the controller 16 detects the three axial force components FX, FY, and FZ acting on each force sensor 13A to 13D by the goods 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 force sensor 13A to 13D based on the three axial force components FX, FY, and FZ of each force sensor 13A to 13D.

[0109] Next, the controller 16 calculates the sum F4=FA+FB+FC+FD of the forces FA, FB, FC, and FD on the upper plate 11, and stores it in the storage unit 164 as the pressure center of the goods placed on the upper plate 11. Then, the controller 16 drives each lifting mechanism 15A to 15D so that the pressure center is located within a prescribed 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 about 2 cm to 4 cm, so that the upper plate 11 is close to horizontal. Thereafter, the controller 16 ends the pressure center output process. In this way, the goods placed on the upper plate 11 of the pallet 1 can be prevented from being scattered.

[0110] As described in detail above, in the stacking system 100 according to the second embodiment, the stacking control device 61 sets the installation position of the cargo held by the robot 55 on the upper plate 11 based on the weight and center of gravity of the cargo held by the robot 55 and the pressure center of the cargo placed on the upper plate 11. Thus, the pressure center on the upper plate 11 can be brought close to the center position 11A of the upper plate 11, thereby preventing the cargo on the pallet 1 from scattering.

[0111] In addition, by placing the goods held by the robot 55 at the installation position of the upper plate 11 estimated by the analysis unit 63 of the stacking control device 61, the pressure center on the upper plate 11 of the pallet 1 is brought close to the center position 11A of the upper plate 11, thereby preventing the goods on the pallet 1 from falling. Furthermore, the robot controller 57 can drive and control the robot 55 and the robot arm 52, thereby reducing the processing of the stacking control device 61.

[0112] [Modification 1]

[0113] In the pallet 1 according to the first embodiment, four force sensors 13A to 13D and four lifting mechanisms 15A to 15D are provided. However, three force sensors and three lifting mechanisms, or five or more force sensors and five or more lifting mechanisms may be provided.

[0114] For example, force sensors 13A and 13B may be installed on the lower surface of the upper plate 11 of the pallet 1 and at both end corners of one side edge of the lower surface, and a force sensor 13C may be installed at a substantially central position of the other side edge facing the one side edge. Furthermore, three lifting mechanisms 15A to 15C may be installed between the three force sensors 13A to 13C and the upper surface of the lower frame 12. Thus, the controller 16 can obtain the pressure center of the cargo placed on the upper plate 11 based on the output signals of the three force sensors 13A to 13C. In addition, the controller 16 can drive the motors 26A to 26C of the three lifting mechanisms 15A to 15C to bring the upper plate 11 close to a horizontal state.

[0115] [Modification 2]

[0116] For example, in the pallet 1 involved in the above-mentioned embodiment 1, each force sensor 13A~13D may be installed at the four corners of the upper surface of the lower frame 12. Moreover, each lifting mechanism 15A~15D may be installed between each force sensor 13A~13D and the four corners of the lower surface of the upper plate 11. Thus, the controller 16 can obtain the pressure center of the goods placed on the upper plate 11 based on the output signal of each force sensor 13A~13D. In addition, the controller 16 can drive each motor 26A~26D of each lifting mechanism 15A~15D to make the upper plate 11 close to the horizontal state.

[0117] [Variation 3]

[0118] For example, in the pallet 1 according to the first embodiment, the lower frame 12 may be composed of a rectangular frame body in a plan view and a cross-shaped crosspiece provided approximately in the center of the opposing side edges of the frame body.

[0119] [Variation 4]

[0120] For example, each of the force sensors 13A to 13D may have a substantially circular shape in a plan view.

[0121] [Variation 5]

[0122] For example, in the pallet 1 involved in the above-mentioned embodiment 1, a plate-shaped rubber or the like having a size substantially the same as that of the bottom plate portion 22 of each lifting mechanism 15A to 15D, for example, a thickness of about 2 cm to 4 cm and a rectangular shape when viewed from above, may be installed at the four corners of the upper surface of the lower frame 12 as a buffer material. Furthermore, the bottom plate portion 22 of each lifting mechanism 15A to 15D may be installed on the upper surface of the buffer material such as the plate-shaped rubber. Thus, when an impact force in a direction orthogonal to the up-and-down direction acts on each lifting mechanism 15A to 15D, the impact force can be weakened by the buffer material such as the plate-shaped rubber, thereby preventing damage to the lower frame 12 and each lifting mechanism 15A to 15D.

[0123] [Additional Notes]

[0124] The present disclosure is not limited to the above-described embodiments and modifications, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the embodiments and modifications are also included in the technical scope of the present disclosure.

[0125] [Note]

[0126] A pallet of the first type comprises: an upper plate for carrying goods; a lower frame arranged opposite to the upper plate; at least three force sensors arranged on the lower surface of the upper plate or the upper surface of the lower frame; at least three lifting mechanisms, wherein the at least three lifting mechanisms are arranged between the upper plate and the lower frame by the force sensors so as to enable the upper plate to be lifted and lowered relative to the lower frame; and a controller, which drives and controls the at least three lifting mechanisms based on output signals of the at least three force sensors.

[0127] According to the pallet of the first embodiment, when the pallet with goods on the upper plate is tilted, the controller can drive and control at least three lifting mechanisms based on the output signals of at least three force sensors to make the upper plate close to a horizontal state. As a result, the controller can prevent the goods from scattering when the pallet is tilted.

[0128] Regarding the pallet of the second embodiment, in the pallet of the first embodiment, the controller drives and controls the at least three lifting mechanisms based on the output signals of the at least three force sensors when the upper plate is horizontal and the current output signals of the at least three force sensors to make the upper plate close to horizontal.

[0129] According to the pallet of the second embodiment, the controller drives and controls at least three lifting 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 make the upper plate close to horizontal. Thus, the controller can make the upper plate close to horizontal when the pallet is tilted, thereby further preventing the goods on the pallet from scattering.

[0130] The stacking system of the third mode comprises: a pallet of the first mode or the second mode; a robot, wherein the robot's manipulator is mounted on the front end of the manipulator arm via a hand force sensor; and a stacking control device, which controls the robot to stack goods on the upper plate of the pallet, wherein the stacking control device has a setting unit, which sets the setting position of the goods held by the manipulator on the upper plate based on the output signal of the hand force sensor and the output signal of the at least three force sensors or the controller, and the stacking control device controls the robot to set the goods held by the manipulator at the setting position of the upper plate set by the setting unit.

[0131] According to the stacking system of the third type, the stacking control device sets the position of the goods held by the manipulator 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 controllers. Thus, the pressure center on the upper plate can be brought close to the center position of the upper plate, thereby preventing the goods on the pallet from scattering.

[0132] Regarding the stacking system of the fourth aspect, in the stacking system of the third aspect, the setting unit sets the placement position of the article gripped by the robot on the upper plate using a learned model generated by machine learning.

[0133] According to the stacking system of the fourth aspect, the placement position of the goods held by the robot is set using the learned model generated by machine learning, thereby making the pressure center on the upper plate closer to the center position of the upper plate, thereby preventing the goods on the pallet from scattering.

Claims

1. A pallet having: An upper plate, which is used to carry cargo; a lower frame, which is arranged facing the upper plate; at least three force sensors, wherein the at least three force sensors are disposed on the lower surface of the upper plate or the upper surface of the lower frame; at least three lifting mechanisms, wherein the at least three lifting mechanisms are arranged between the upper plate and the lower frame via the force sensor and are capable of lifting the upper plate relative to the lower frame; and A controller controls the driving of the at least three lifting mechanisms based on output signals of the at least three force sensors.

2. The pallet according to claim 1, wherein: The controller drives and controls the at least three lifting mechanisms based on output signals of the at least three force sensors when the upper plate is horizontal and current output signals of the at least three force sensors to make the upper plate close to horizontal.

3. A stacking system comprising: The pallet according to claim 1 or 2; A robot, wherein a manipulator of the robot is mounted on a front end of a manipulator arm via a hand force sensor; and a stacking control device for controlling the robot to stack goods on the upper plate of the pallet, in, The stacking control device includes a setting unit, which sets a setting position of the goods held by the robot on the upper plate based on an output signal of the hand force sensor and an output signal of the at least three force sensors or the controller. The stack control device controls the robot to place the article held by the robot arm at the placement position of the upper plate set by the setting unit.

4. The stacking system according to claim 3, wherein: The setting unit sets a placement position of the article held by the robot on the upper plate using a learned model generated by machine learning.

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