Gripping device and control method for gripping device

Abstract

To provide a gripping device and a control method for the gripping device that are capable of improving conveyance capacity. This gripping device is provided with: a gripping part that has an attachment surface that can be attached to the upper surface of one or more articles; a connection part that connects the distal end of the arm of the transport device with the gripping part; and a control device that sets, on the basis of the position of the center of gravity of the article to be gripped, a gripping center position that is the horizontal position of the distal end of the arm with respect to the gripping part.

Description

Grip device and grip device control method

[0001] The present invention relates to a gripping device and a method for controlling a gripping device.

[0002] There are known conveyance devices such as palletizing devices and depalletizing devices that stack articles on pallets, unload articles from pallets, or transfer articles from one pallet to another. For example, Patent Document 1 discloses a gripping device that is an end effector of a robot arm and grips an object at its bottom.

[0003] Japanese Patent Application Laid-Open No. 2021-030431

[0004] The gripping device of Patent Document 1 has multiple (e.g., three) grippers, and can grip a load by suction using only the other grippers without operating some of the grippers. It is also preferable to grip a single load with a single gripper, rather than using multiple grippers. However, if the load is unevenly distributed across the grippers, a moment is generated due to a misalignment between the center of gravity of the load and the tool centering point (TCP), which increases the load on the robot arm and reduces the conveyance speed.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a gripping device and a control method for a gripping device that can improve conveying capacity.

[0006] In order to achieve the above-mentioned object, a gripping device according to one aspect of the present disclosure comprises a gripping section having an adsorption surface capable of adsorbing to the upper surface of one or more articles, a connection section that connects the tip of the arm of a conveying device to the gripping section, and a control device that sets a gripping center position, which is the horizontal position of the tip of the arm relative to the gripping section, based on the center of gravity position of the article to be gripped.

[0007] In order to achieve the above-mentioned object, a control method for a gripping device according to one aspect of the present disclosure includes a transport target data acquisition step for acquiring transport target data including at least data on the dimensions and weight of the item to be gripped by the gripping device, an image data acquisition step for acquiring image data of a predetermined area including the item to be gripped, a center of gravity position calculation step for calculating the center of gravity position of the item to be gripped based on the transport target data and the image data, and a gripping center position setting step for setting the gripping center position based on the center of gravity position.

[0008] According to the present disclosure, it is possible to obtain the effect of improving the conveying capacity.

[0009] Fig. 1 is a schematic diagram of a gripping device according to this embodiment. Fig. 2 is a schematic diagram showing an aspect in which the gripping center position of the gripping device shown in Fig. 1 has been adjusted. Fig. 3 is a schematic block diagram of the gripping device shown in Fig. 1. Fig. 4 is a flowchart illustrating the processing flow of the control device. Fig. 5 is a plan view schematically illustrating the center of gravity position of an article to be gripped. Fig. 6 is a plan view schematically illustrating the center of gravity position of an article to be gripped.

[0010] (Embodiments) Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are easily replaceable by those skilled in the art, those that are substantially identical, or those that are equivalent. Furthermore, the components in the following embodiments can be variously omitted, replaced, or modified without departing from the gist of the present disclosure. In the following embodiments, components necessary for illustrating the embodiments will be described, and other components will be omitted. The same components will be assigned the same reference numerals, and different components will be assigned different reference numerals.

[0011] Fig. 1 is a schematic diagram of a gripping device according to this embodiment. Fig. 2 is a schematic diagram showing an aspect in which the gripping center position of the gripping device shown in Fig. 1 has been adjusted. Fig. 3 is a schematic block diagram of the gripping device shown in Fig. 1. The gripping device 1 shown in Figs. 1 to 3 is attached to the tip of an arm RA of a palletizing device serving as a conveying device, and is a device that stacks articles on a pallet, unloads articles from a pallet, or transfers articles from one pallet to another in a facility that is subject to logistics management, such as a warehouse. The gripping device 1 is capable of simultaneously gripping and conveying multiple articles R whose upper surfaces are located on the same horizontal plane.

[0012] Here, the Japan Pallet Association defines a pallet as "a surface on which a single unit of cargo is placed, with a structure that allows for all loading, transport, and storage by hand or by dedicated vehicles such as forklifts. This includes those with superstructures." In this embodiment, a pallet refers to a container or platform on which goods R are stacked. In other words, the pallet referred to here is not limited to a so-called flat platform, but also includes a cart or the like, and may be of any shape. Goods R are stacked on a pallet, such as goods to be shipped. Note that the term "goods R" also refers to cardboard boxes and the like in which goods are packaged. Goods R have at least a flat top surface, and in this embodiment, a rectangular cardboard box is assumed.

[0013] 1 to 3, the gripping device 1 includes a base 10, a connection unit 20, an adjustment mechanism 30, and a gripping unit 40. As shown in Fig. 4, the gripping device 1 further includes an imaging device 70, an input / output device 80, and a control device 90 that controls the operation of each part of the gripping device 1. Note that in this embodiment, the gripping device 1 including the imaging device 70, the input / output device 80, and the control device 90 also includes an embodiment in which the functions of each of these devices are configured as part of the functions of a palletizing device to which the gripping device 1 is attached or a conveyance system in which the palletizing device is deployed.

[0014] In this embodiment, the X-axis direction is a direction parallel to the suction surfaces (first suction surface 42a and second suction surface 44a) of the gripping device 1 that grip the top surface of the article R, the Y-axis direction is a direction parallel to the suction surfaces (first suction surface 42a and second suction surface 44a) of the gripping device 1 that grip the top surface of the article R and perpendicular to the X-axis direction, and the Z-direction is a direction perpendicular to the X-axis and Y-axis directions. At least during operation of the gripping device 1, the X-axis and Y-axis directions correspond to the horizontal direction, and the Z direction corresponds to the vertical direction.

[0015] 1 and 2 is connected to the tip of the arm RA of the palletizing device to which the gripping device 1 is attached via a connection part 20. The connection part 20 connects the tip of the arm RA of the palletizing device to which the gripping device 1 is attached to the base 10 so that the tip can move relatively in the X and Y directions. The connection part 20 connects the tip of the arm RA to the gripping part 40 via the base 10. Note that in the example shown in FIGS. 1 and 2, only the configuration that is relatively movable in the X direction is shown, and the configuration that is relatively movable in the Y direction is not shown. The connection part 20 has a linear guide part 22, a movable connection part 24, and a linking part 26.

[0016] The linear motion guide portion 22 guides the linear motion of the movable connection portion 24 in the X direction relative to the base 10. The linear motion guide portion 22 is realized, for example, by a linear guide fixed to the upper surface of the base 10, or a groove or rail formed on the upper surface side of the base 10. In the example shown in FIGS. 1 and 2 , the linear motion guide portion 22 supports the lower end of the movable connection portion 24 and regulates the linear motion of the movable connection portion 24 in the Y direction and the Z direction relative to the base 10. The linear motion guide portion 22 also regulates the rotational movement of the movable connection portion 24 relative to the base 10.

[0017] The movable connecting part 24 is supported at its lower end so as to be linearly movable in the X direction relative to the linear guide part 22. The movable connecting part 24 is linearly moved in the X direction relative to the linear guide part 22 by an adjustment mechanism 30 between directly above the center of a gripping part 40 (described below) and directly above the center of a second suction part 44. A connecting part 26 is fixed to the upper end of the movable connecting part 24. The connecting part 26 is connected to the tip of an arm RA of the palletizing device to which the gripping device 1 is attached.

[0018] For example, if the palletizing device to which the gripping device 1 is attached is an articulated robot, the cooperative operation of multiple axes of the articulated robot will realize the lifting and lowering movement of the gripping device 1 in the Z direction and the rotation movement around the Z axis via the tip of the arm RA. For example, if the palletizing device to which the gripping device 1 is attached is a Cartesian coordinate robot, the operation of the vertical prismatic joint of the Cartesian coordinate robot will realize the lifting and lowering movement of the gripping device 1 in the Z direction via the tip of the arm RA.

[0019] The adjustment mechanism 30 linearly moves the base 10 and the gripping unit 40 in the X direction relative to the coupling unit 26 and the arm RA via the movable connecting unit 24. In other words, the adjustment mechanism 30 adjusts the position of the gripping unit 40 in the X direction relative to the arm RA. The adjustment mechanism 30 is realized by a well-known mechanism, such as a linear actuator including a motor or an air cylinder, or a rack-and-pinion mechanism. In this embodiment, the adjustment mechanism 30 includes a fixed unit 32, a movable unit 34, and an adjustment drive unit 36 ​​(see FIG. 3 ). The fixed unit 32 is fixed to the base 10. The fixed unit 32 supports the movable unit 34 so that the movable unit 34 can move linearly in the X direction within a predetermined range. The movable unit 34 can move in the X direction relative to the fixed unit 32. The movable unit 34 is fixed to the movable connecting unit 24.

[0020] For example, if the adjustment mechanism 30 includes an air cylinder, the fixed part 32 is the cylinder, the movable part 34 is a rod, and the adjustment drive part 36 is an air supply mechanism. The adjustment mechanism 30 has a locking mechanism (not shown) that can position the horizontal position of the gripping part 40 relative to the arm RA by positioning the X-direction position of the movable part 34 relative to the fixed part 32. The locking mechanism is realized by a well-known mechanism such as an air lock using high-pressure air, a mechanical lock driven by a motor, or a solenoid lock using an electromagnetic solenoid.

[0021] 1 and 2 show the connection part 20 and adjustment mechanism 30 that can move the base part 10 and the tip of the arm RA relatively in the X direction, but the connection part 20 and adjustment mechanism 30 of the present invention may be provided so as to move the base part 10 and the tip of the arm RA relatively in the X direction and the Y direction. For example, the linking part 26 may be provided so as to be movable in the Y direction relative to the movable connection part 24, and the second adjustment mechanism 30 may be provided so as to move the linking part 26 linearly with respect to the movable connection part 24. In other words, the adjustment mechanism 30 adjusts the horizontal position of the grip part 40 with respect to the arm RA.

[0022] The gripping unit 40 is provided on the lower part of the base 10. The gripping unit 40 has an opposing surface 40a on its lower surface that faces the upper surface of the article R. The gripping unit 40 is fixed to the base 10 so that the opposing surface 40a is perpendicular to the Z direction. The gripping unit 40 moves up and down and rotates in accordance with the lifting and rotating movements of the base 10 and the connection unit 20. The gripping unit 40 has a plurality of suction portions on the opposing surface 40a that can suction the article R.

[0023] The plurality of suction portions are arranged side by side in the X direction, and in the example shown in Figures 1 and 2, there are two suction portions, a first suction portion 42 and a second suction portion 44, but in the present invention, three or more suction portions may be provided. The plurality of suction portions may also be arranged side by side in the X direction and the Y direction. In the example shown in Figures 1 and 2, the first suction portion 42 and the second suction portion 44 are each depicted as a single block shape, but may instead be, for example, a plurality of suction pads protruding downward from the opposing surface 40a of the gripping portion 40.

[0024] The first suction portion 42 has a first suction surface 42a at its lower end, which is the end opposite to the opposing surface 40a. When the first suction surface 42a is in contact with the upper surface of the article R, the first suction portion 42 adheres to the upper surface of the article R with the first suction surface 42a by activating a first suction mechanism 46 shown in FIG. 3 . The first suction mechanism 46 includes, for example, a vacuum generator connected to the first suction surface 42a via an air pipe (not shown) and configured to suck air from the first suction surface 42a. For example, if the first suction portion 42 is configured with multiple suction pads, each suction pad is connected to the first suction mechanism 46, which is a vacuum generator, via an air pipe. The operation of the first suction mechanism 46 is controlled by a control unit 96 of the control device 90.

[0025] The second suction portion 44 has a second suction surface 44a at its lower end, which is the end opposite to the opposing surface 40a. When the second suction surface 44a is in contact with the side surface of the article R, the second suction portion 44 adheres to the side surface of the article R with the second suction surface 44a by activating a second suction mechanism 48 shown in FIG. 3. The second suction mechanism 48 includes, for example, a vacuum generator connected to the second suction surface 44a via an air pipe (not shown) and sucking air from the second suction surface 44a. For example, if the second suction portion 44 is composed of multiple suction pads, each suction pad is connected to the second suction mechanism 48, which is a vacuum generator, via an air pipe. The operation of the second suction mechanism 48 is controlled by the control unit 96 of the control device 90.

[0026] The gripping device 1 includes a plurality of suction mechanisms (first suction mechanism 46 and second suction mechanism 48) that respectively activate suction on a suction surface (first suction surface 42a and second suction surface 44a) that is divided into a plurality of regions. For example, as shown in FIG. 1, two articles R may be gripped by the first suction portion 42 and the second suction portion 44, respectively. Alternatively, as shown in FIG. 2, one article R may be gripped by the second suction portion 44. In this case, suction on the first suction surface 42a of the first suction portion 42 can be stopped by stopping the first suction mechanism 46.

[0027] The imaging device 70 captures images of a pallet on which the items R are to be loaded or unloaded, the items R loaded on the pallet, and the stacked arrangement of the items R, and outputs image data that can identify the position and individual items of the imaged objects to the control device 90. The imaging device 70 is placed in a position where the pallet and the items R loaded on the pallet can be observed. The imaging device 70 includes one or more cameras.

[0028] The input / output device 80 includes an input device through which the worker inputs various pieces of information for operating the gripping device 1, and an output device for presenting various pieces of information to the worker. The input device is realized by, for example, a keyboard, a mouse, a physical switch, a button, a touch panel, or the like. The output device is realized by, for example, a display device such as a liquid crystal display device or an organic EL (Electro Luminescence) display device, a light-emitting device such as an LED (Light Emitting Diode), or a speaker, or the like. The input / output device 80 may be an information terminal capable of inputting and outputting various pieces of information.

[0029] The control device 90 is a computer that controls the gripping device 1. The control device 90 has a communication unit 92, a storage unit 94, and a control unit 96. The communication unit 92 is a module used by the control unit 96 to communicate with external devices such as the management device 100, and may include, for example, an antenna. In this embodiment, wireless communication is assumed as the communication method used by the communication unit 92, but any communication method may be used. The storage unit 94 is a memory that stores the calculation contents and programs of the control unit 96, and various information acquired from the management device 100 via the communication unit 92, and includes, for example, at least one of a main storage device such as a random access memory (RAM), a read-only memory (ROM), and an external storage device such as an HDD (hard disk drive).

[0030] The control unit 96 is an arithmetic processing device and includes an arithmetic circuit such as a CPU (Central Processing Unit). The control unit 96 executes various processes by reading and executing programs (software) from the storage unit 94. The control unit 96 may execute processes using a single CPU, or may be provided with multiple CPUs and execute processes using the multiple CPUs.

[0031] The control unit 96 acquires upstream data from the management device 100 via the communication unit 92. The upstream data includes, for example, transport target data such as the type, weight, dimensions, box perforations, number of glued items, number of items R, placement of each item R on the pallet or the position where the items R are stacked on the pallet, and the order in which the items R are unloaded from the pallet or stacked on the pallet. The control unit 96 causes the imaging device 70 to capture an image at any timing and acquires image data. The control unit 96 processes the acquired image data to recognize the number, position, shape, size, etc. of the items R present in the image data.

[0032] The control unit 96 calculates the position of the center of gravity G of the item R to be gripped based on the image data and the transport object data. The control unit 96 sets the gripping center position TCP (the horizontal position of the tip of the arm RA) based on the calculated position of the center of gravity G. The control unit 96 controls the adjustment drive unit 36 ​​to adjust the horizontal position of the gripping center position TCP. The control unit 96 activates at least one of the first suction mechanism 46 and the second suction mechanism 48 to cause the gripper 40 to suck and grip the item R. The control unit 96 executes control to move the gripping device 1 itself in a palletizing device to which the gripping device 1 is attached. If the palletizing device is a multi-joint robot, the movement of the gripping device 1 itself is achieved by the cooperative operation of multiple axes of the multi-joint robot.

[0033] The management device 100 is a system that manages the operation of each device in a logistics management facility in which the gripping device 1 of this embodiment is deployed. The management device 100 is, for example, a WCS (Warehouse Control System) or a WMS (Warehouse Management System), but is not limited to a WCS or a WMS and may be any system, such as a back-end system such as another production management system. The management device 100 may be installed at any location, and may be installed within the facility in which the gripping device 1 is deployed, or may be installed at a location remote from the facility to manage the facility from that location.

[0034] (Processing of the control device) Next, the flow of processing for adjusting the gripping center position TCP during transportation by the gripping device 1 will be described. Here, the case of unloading multiple items R stacked on a pallet will be described. FIG. 4 is a flowchart illustrating the processing flow of the control device. The processing shown in FIG. 4 is executed by the control unit 96 of the control device 90 based on programs and data pre-stored in the memory unit 94. For example, upon receiving a predetermined control signal from the management device 100 instructing the gripping device 1 to be driven, the control device 90 proceeds to step S10 shown in FIG. 4 and starts processing.

[0035] The control device 90 acquires the transport target data (step S10). In this embodiment, the control device 90 acquires the transport target data from the management device 100 via the communication unit 92. In this process, the transport target data includes at least data on the dimensions and weight of each item R to be grasped.

[0036] The control device 90 acquires captured image data (step S12). In this embodiment, the control device 90 causes the imaging device 70 to capture an image of a predetermined area including the item R to be grasped. The imaging device 70 outputs captured image data indicating data of the captured image to the control device 90. The captured image data may be linked to coordinate data of a coordinate system based on, for example, a predetermined position of the gripping device 1 or the facility in which the gripping device 1 is deployed. The control device 90 performs image processing on the captured image data to recognize the position, shape, dimensions, etc. of the item R to be grasped.

[0037] The control device 90 calculates the position of the center of gravity G of the item R to be grasped (step S14). The control device 90 identifies the position of the center of gravity G of the item R to be grasped based on the position, shape, and dimensions of the item R to be grasped extracted based on the captured image data acquired in step S12. The gripping device 1 can grasp multiple items R at once if the height dimensions of the items R are the same. When grasping multiple items R at once, the control device 90 calculates the position of the combined center of gravity of the multiple items R to be grasped based on the positions of the centers of gravity G of all the items R to be grasped and the weight data of the items R included in the transport target data acquired in step S10.

[0038] The control device 90 sets the gripping center position TCP (step S16). More specifically, the control device 90 sets the gripping center position TCP corresponding to the tip of the arm RA based on the position of the center of gravity G of the article R to be gripped calculated in step S14, and sets the amount of movement adjustment by the adjustment mechanism 30 so that the movable connecting part 24 is positioned at a position corresponding to the gripping center position TCP.

[0039] For example, as shown in the example of Fig. 1 , when two articles R of the same size and weight are gripped by the first suction portion 42 and the second suction portion 44, the combined center of gravity of the two articles R as a whole is located directly below the center of the gripping portion 40. In this case, for example, the gripping center position TCP is set directly above the combined center of gravity, and a movement adjustment amount is set so that the X-direction position of the movable connecting portion 24 is located directly above the center of the gripping portion 40. Also, as shown in the example of Fig. 2 , when one article R is gripped by the second suction portion 44, the center of gravity G of the article R is located directly below the center of the second suction portion 44. In this case, the gripping center position TCP is set directly above the center of gravity G, and a movement adjustment amount is set so that the X-direction position of the movable connecting portion 24 is located directly above the center of the second suction portion 44.

[0040] The control device 90 adjusts the gripping center position TCP and grips the object R to be gripped (step S18). The control device 90 first controls the arm RA to move and rotate the gripping device 1 to a position where the upper surface of the object R to be gripped faces the areas of the first suction surface 42a and the second suction surface 44a that grip the object R. The control device 90 then controls the adjustment drive unit 36 ​​to move the movable connecting part 24 in the X direction along the linear guide part 22 by the movement adjustment amount set in step S16, thereby adjusting the gripping center position TCP.

[0041] The control device 90 then lowers the gripping device 1, bringing the top surface of the article R to be gripped into contact with the areas of the first suction surface 42a and the second suction surface 44a that grip the article R. The control device 90 then activates at least one of the first suction mechanism 46 and the second suction mechanism 48 to suction the top surface of the article R to at least one of the first suction surface 42a and the second suction surface 44a. This causes the gripping device 1 to grip the article R with the gripping section 40.

[0042] The control device 90 transports (unloads) the item R (step S20). The control device 90 controls the arm RA to raise the gripping device 1 gripping the item R, then transports it to a predetermined position and unloads the item R from the pallet. The control device 90 repeatedly executes the processes from step S10 to step S20 shown in Fig. 4 until, for example, all of the items R are unloaded from the pallet.

[0043] In the process of this embodiment shown in FIG. 4, step S12 has been described as being performed for each transport. However, for example, when the items R are arranged flat on the pallet, i.e., when multiple items R are not stacked vertically, step S12 of capturing an image of all the items R on the pallet may be performed only the first time. Similarly, step S10 may also be performed to acquire all transport target data for all the items R stacked on the pallet at once at the beginning. Furthermore, while the above description is of the process of unloading items R from a pallet on which multiple items R are stacked, the process of this embodiment shown in FIG. 4 can also be applied to the case of stacking multiple items R on a pallet or transferring items from one pallet to another pallet.

[0044] Furthermore, although the gripping center position TCP is adjusted only in the X direction in the above description, if the adjustment mechanism 30 of the gripping device 1 allows adjustment in the Y direction as well, the gripping center position TCP may also be adjusted in the Y direction based on the Y-direction position of the center of gravity G of the item R to be gripped. Furthermore, if there is a deviation in the position of the center of gravity of the gripping device 1 itself with respect to the suction surfaces (first suction surface 42a and second suction surface 44a), it is preferable to set the gripping center position TCP based on the composite center of gravity of the gripping device 1 and the center of gravity G of the item R to be gripped, rather than the center of gravity G (composite center of gravity) of only the item R to be gripped.

[0045] (Method of calculating center of gravity position) A method of calculating the position of the center of gravity G of multiple items R to be grasped will be described. When multiple items R are to be grasped at once, it is necessary that the height of the upper surfaces of the multiple items R is the same.

[0046]

[0033] A method for calculating a combined center of gravity G when two items R1 and R2 are aligned in only one direction in a plan view and their respective centers of gravity G1 and G2 are on the same straight line will be described. FIG. 5 is a plan view that schematically illustrates the center of gravity positions of the items to be grasped. In the example shown in FIG. 5, the center of gravity G1 of item R1 and the center of gravity G2 of item R2 are aligned in the X direction in a plan view. If the weight of item R1 is m1, the weight of item R2 is m2, the distance between the combined center of gravity G of the two items R1 and R2 and the center of gravity G1 is L1, the distance between the center of gravity G and the center of gravity G2 is L2, and the distance between the center of gravity G1 and the center of gravity G2 is L, the distances L1 and L2 are expressed by equations (1) and (2).

[0047]

[0048]

[0049] Next, a method for calculating a composite center of gravity G will be described, which is not limited to the example shown in FIG. 5 and can be applied even when the centers of gravity G1, G2, and G3 of multiple items R1, R2, and R3 are not on the same line. FIG. 6 is a plan view that schematically illustrates the position of the center of gravity of an item to be grasped. In the example shown in FIG. 6, the center of gravity G1 of item R1, the center of gravity G2 of item R2, and the center of gravity G3 of item R3 are not on the same line in a plan view. Furthermore, the coordinates of the center of gravity G1 of item R1 are (x Ｇ１ , y Ｇ１ ), and the coordinates of the center of gravity G2 of the item R2 are (x Ｇ２ , y Ｇ２ ), and the coordinates of the center of gravity G3 of the item R3 are (x Ｇ３ , y Ｇ３ ) The number of items is n, and the weight of each of the n items R1, ..., Ri, ..., Rn is m １ , ..., m ｉ , ..., m ｎ Then, the coordinates of the combined center of gravity G of n items R1, ..., Ri, ..., Rn (x Ｇ , y Ｇ ) is shown by equations (3) and (4).

[0050]

[0051]

[0052] (Operation and Effect of the Embodiment) The gripping device 1 and the control method of the gripping device 1 described in the embodiment can be understood, for example, as follows.

[0053] The gripping device 1 of the first embodiment comprises a gripping unit 40 having suction surfaces (first suction surface 42a and second suction surface 44a) that can be adsorbed onto the upper surface of one or more items R, a connection unit 20 that connects the tip of the arm RA of the conveying device to the gripping unit 40, and a control device 90 that sets the gripping center position TCP, which is the horizontal position of the tip of the arm RA relative to the gripping unit 40, based on the position of the center of gravity G of the item R to be gripped.

[0054] The gripping device 1 according to the first aspect can set the gripping center position TCP based on the position of the center of gravity G of the article R to be gripped, and can therefore adjust the gripping center position TCP to a suitable position even when gripping various sizes and numbers of articles R at once. This makes it possible to suppress the moment load caused by the center of gravity G of the article R to be gripped relative to the gripping center position TCP. This reduces the load on mechanical components such as bearings and sliding parts of the gripping device 1 and the conveying device to which the gripping device 1 is attached, and also reduces load shaking, thereby improving the maximum conveying speed and thereby improving conveying capacity.

[0055] In the gripping device 1 of the second aspect, the control device 90 calculates the combined center of gravity G position of all items R to be gripped based on transport target data that includes at least data on the dimensions and weight of all items R to be gripped and image data that captures a specified area including all items R to be gripped.

[0056] The gripping device 1 according to the second aspect calculates the position of the center of gravity G of the item R to be gripped, for setting the gripping center position TCP, based on the transport object data and the captured image data. The transport object data can be included in the order data handled in the transport system, so this can be realized without the need to build a new system. Similarly, the imaging device 70 that captures the captured image can be, for example, an imaging device for monitoring or the like installed in the transport system, so this can be realized without the need for a new device.

[0057] In the gripping device 1 of the third aspect, the connection portion 20 connects the tip of the arm RA and the gripping portion 40 so that they can move horizontally relative to each other, and the gripping device 1 further includes an adjustment mechanism 30 that moves the gripping portion 40 horizontally relative to the tip of the arm RA, and the control device 90 controls the adjustment mechanism 30 based on the set gripping center position TCP.

[0058] The gripping device 1 according to the third aspect sets the gripping center position TCP based on the position of the center of gravity G of the article R to be gripped, and can automatically move the gripping unit 40 horizontally so that the set gripping center position TCP coincides with the tip of the arm RA. This makes it possible to adjust the gripping center position TCP to a suitable position each time, even when gripping and transporting various articles R one after another. Therefore, the moment load caused by the center of gravity G of the article R to be gripped relative to the gripping center position TCP can be constantly suppressed, thereby improving transport capacity.

[0059] In the gripping device 1 according to the fourth aspect, the connection portion 20 connects the tip of the arm RA and the gripping portion 40 so that they can move relative to each other in one horizontal direction (X direction), the gripping device 1 further includes an adjustment mechanism 30 that moves the gripping portion 40 in one direction (X direction) relative to the tip of the arm RA, and the control device 90 controls the adjustment mechanism 30 based on the set gripping center position TCP.

[0060] The gripping device 1 according to the fourth aspect sets the gripping center position TCP based on the position of the center of gravity G of the article R to be gripped, and can automatically move the gripping unit 40 in one direction (X direction) so that the set gripping center position TCP coincides with the tip of the arm RA. This makes it possible to adjust the gripping center position TCP to a suitable position each time, even when gripping and transporting various articles R one after another. Therefore, the moment load caused by the center of gravity G of the article R to be gripped relative to the gripping center position TCP can be constantly suppressed, thereby improving transport capacity.

[0061] In the gripping device 1 relating to the fifth aspect, the suction surface includes an suction surface (first suction surface 42a and second suction surface 44a) divided into multiple regions, and the gripping device 1 further includes multiple suction mechanisms (first suction mechanism 46 and second suction mechanism 48) that each activate suction on the suction surface when each suction surface is in contact with the upper surface of the article R.

[0062] The gripping device 1 of the fifth aspect can activate the adsorption of each area of ​​the adsorption surface using multiple adsorption mechanisms, and therefore can stop the adsorption of parts of the adsorption surface that are not in contact with the item R.

[0063] The gripping device 1 according to the sixth aspect has a locking mechanism for determining the horizontal position of the gripping portion 40 relative to the arm RA.

[0064] The gripping device 1 according to the sixth aspect can fix the horizontal position of the gripping part 40 relative to the arm RA when gripping and transporting the article R with the gripping part 40, thereby preventing the position of the gripping part 40 relative to the arm RA from shifting during transport and preventing the central position TCP from shifting from the position of the center of gravity G. This allows the article to be transported stably.

[0065] The control method for the gripping device 1 relating to the seventh aspect is a control method for the gripping device 1 in any one of the first to sixth aspects, and includes a transport target data acquisition step (step S10) for acquiring transport target data including at least data on the dimensions and weight of the item R to be gripped by the gripping device 1, an image data acquisition step (step S12) for acquiring image data of a predetermined area including the item R to be gripped, a center of gravity position calculation step (step S14) for calculating the center of gravity G position of the item R to be gripped based on the transport target data and the image data, and a gripping center position setting step (step S16) for setting the gripping center position TCP based on the center of gravity G position.

[0066] The control method for the gripping device 1 according to the seventh aspect calculates the position of the center of gravity G based on the dimensions and weight of the article R to be gripped and the position of the article R based on the captured image data, and can set the gripping center position TCP based on the position of the center of gravity G. This makes it possible to adjust the gripping center position TCP to a suitable position, thereby suppressing the moment load caused by the center of gravity G of the article R to be gripped relative to the gripping center position TCP. Therefore, the load on the gripping device 1 and mechanical parts such as bearings and sliding parts of the conveying device to which the gripping device 1 is attached is reduced, and the maximum conveying speed can be improved by reducing load shaking, thereby improving conveying capacity.

[0067] The control method of the gripping device 1 relating to the eighth aspect further includes an adjustment gripping step (step S18) in which the gripping unit 40 is moved horizontally relative to the tip of the arm RA so that the tip of the arm RA is aligned with the set gripping center position TCP, and the item R is gripped by the suction surfaces (first suction surface 42a and second suction surface 44a) of the gripping unit 40, and a transport step (step S20) in which the item R is transported in a gripped state.

[0068] The control method of the gripping device 1 according to the eighth aspect can automatically move the gripping unit 40 horizontally so that the set gripping center position TCP coincides with the tip of the arm RA. This makes it possible to adjust the gripping center position TCP to a suitable position each time, even when gripping and transporting various articles R one after another. Therefore, the moment load caused by the center of gravity G of the article R to be gripped relative to the gripping center position TCP can be constantly suppressed, thereby improving transport capacity.

[0069] Although the embodiments of the present disclosure have been described above, the embodiments are not limited to the contents of the description of these embodiments.

[0070] DESCRIPTION OF SYMBOLS 1 Grip device 10 Base 20 Connection part 22 Linear guide part 24 Movable connection part 26 Linking part 30 Adjustment mechanism 32 Fixed part 34 Movable part 36 Adjustment drive part 40 Grip part 40a Opposing surface 42 First suction part 42a First suction surface 44 Second suction part 44a Second suction surface 46 First suction mechanism 48 Second suction mechanism 70 Imaging device 80 Input / output device 90 Control device 92 Communication part 94 Memory part 96 Control part 100 Management device RA Arm R, R1, R2, R3 Article G, G1, G2, G3 Center of gravity L, L1, L2 Distance

Claims

1. A gripping device comprising: a gripping unit having an adsorption surface capable of adsorbing to the upper surface of one or more articles; a connection unit that connects the tip of an arm of a conveying device to the gripping unit; and a control device that sets a gripping center position, which is the horizontal position of the tip of the arm relative to the gripping unit, based on the center of gravity of the article to be gripped.

2. The gripping device described in claim 1, wherein the control device calculates a combined center of gravity position of all items to be gripped based on transport object data including at least dimensional and weight data of all items to be gripped and image data capturing an image of a specified area including all items to be gripped.

3. The gripping device described in claim 1, wherein the connection portion connects the tip of the arm and the gripping portion so as to be movable relative to each other in the horizontal direction, and further comprises an adjustment mechanism for moving the gripping portion in the horizontal direction relative to the tip of the arm, and the control device controls the adjustment mechanism based on the set gripping center position.

4. The gripping device described in claim 1, wherein the connection portion connects the tip of the arm and the gripping portion so as to be movable relative to one another in a horizontal direction, and the gripping device further comprises an adjustment mechanism for moving the gripping portion in said one direction relative to the tip of the arm, and the control device controls the adjustment mechanism based on the set gripping center position.

5. The gripping device according to claim 1, wherein the suction surface includes an suction surface divided into a plurality of regions, and further comprises a plurality of suction mechanisms each activating suction on the suction surface when each suction surface is in contact with the upper surface of the article.

6. The gripping device according to claim 1, further comprising a locking mechanism for determining the horizontal position of the gripping part relative to the arm.

7. A control method for a gripping device as described in any one of claims 1 to 6, comprising: a transport target data acquisition step for acquiring transport target data including at least data on the dimensions and weight of an item to be gripped by the gripping device; an image data acquisition step for acquiring image data of a specified area including the item to be gripped; a center of gravity position calculation step for calculating the center of gravity position of the item to be gripped based on the transport target data and the image data; and a gripping center position setting step for setting the gripping center position based on the center of gravity position.

8. A method for controlling a gripping device as described in claim 7, further comprising: an adjustment gripping step of gripping the article with the suction surface of the gripping part while moving the gripping part horizontally relative to the tip of the arm so that the tip of the arm coincides with the set gripping center position; and a transport step of transporting the article in a gripped state.

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