TW202515708A - Robotic system and method for holding objects - Google Patents

Abstract

There has previously been a desire to make it possible to effectively grip articles of various sizes using a robot hand, and to automate the work of gripping such articles of various sizes. A robot system 10 comprises: a robot 12 that has a robot hand 50 including a first suction opening and a second suction opening, the opening dimensions thereof being different from each other; and a control device 20 that operates the robot 12 to move the robot hand 50, and executes a gripping operation for gripping an article W using the robot hand 50. The control device 20 acquires the surface size of the article to be gripped, and in accordance with the acquired surface size, determines the number of first suction openings and the number of second suction openings to use for the gripping operation.

Description

Robotic system and method for holding objects

The present disclosure relates to a robotic system, method and computer program for holding objects.

It is known that there is a robot hand that can hold an object (e.g., Patent Document 1). [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 2021-79505

[The problem the invention is trying to solve]

Previously, robots could effectively hold objects of various sizes, and there was a demand to automate the operation of holding objects of various sizes. [Technical means to solve the problem]

In one aspect of the present disclosure, a robot system for holding an object comprises: a robot having a manipulator including a first suction port and a second suction port with opening sizes different from each other; and a control device, which causes the robot to move the manipulator to perform a holding action of holding an object with the manipulator. The control device obtains the surface size of the object to be held, and determines the number of the first suction ports and the number of the second suction ports used for the holding action based on the obtained surface size.

A method for holding an object by a robot including a first suction port and a second suction port having opening sizes different from each other is to obtain the surface size of the object to be held, and determine the number of the first suction port and the number of the second suction port used for the holding action of the robot to hold the object based on the obtained surface size.

The following is a detailed description of the embodiments of the present disclosure based on the drawings. In addition, in the various embodiments described below, the same elements are marked with the same symbols, and repeated descriptions are omitted. First, referring to Figures 1 and 2, a robot system 10 of an embodiment is described. The robot system 10 includes a robot 12, a visual sensor 14, a first exhaust device 16 (Figure 2), a second exhaust device 18A, 18B, 18C and 18D (Figure 2), and a control device 20.

In this embodiment, the robot 12 is a vertical multi-joint robot, and has a robot base 22, a rotating body 24, a lower arm 26, an upper arm 28, a wrist 30, and a manipulator 50. The robot base 22 is fixed on the floor of the work unit or an AGV (Automated Guided Vehicle). The rotating body 24 is arranged on the robot base 22 in a manner that it can rotate around a lead straight axis.

The base end of the lower arm 26 is rotatably provided on the rotating body 24 around a horizontal axis, and the base end of the upper arm 28 is rotatably provided on the front end of the lower arm 26. The wrist 30 includes a wrist base 30a rotatably provided on the front end of the upper arm 28 around two axes orthogonal to each other, and a wrist flange 30b rotatably provided on the wrist base 30a around a wrist axis A1.

The robot base 22, the rotating body 24, the lower arm 26, the upper arm 28 and the wrist 30 are respectively provided with a servo motor 32 (FIG. 2). The servo motor 32 moves the robot 50 by rotating the rotating body 24, the lower arm 26, the upper arm 28, the wrist base 30a and the wrist flange 30b around their respective drive axes. Therefore, the robot base 22, the rotating body 24, the lower arm 26, the upper arm 28 and the wrist 30 (the wrist base 30a and the wrist flange 30b) constitute a moving mechanism 34 (FIG. 1) that moves the robot 50.

The manipulator 50 is detachably mounted on the wrist flange 30b of the moving mechanism 34. The structure of the manipulator 50 is described below with reference to FIGS. 3 to 7. In the following description, the direction along the axis A2 in the figure is referred to as the axial direction, the radius direction of the circle with the axis A2 as the center is referred to as the radial direction, and the circumferential direction of the circle is referred to as the circumferential direction. In addition, for convenience, the direction of the arrow B in FIG. 3 is referred to as the axial downward direction.

The robot 50 has a hand base 52, a suction hand 54 and an adsorption hand 56. The hand base 52 has a mounting flange 58, a support platform 60 and a plurality of column portions 62. The mounting flange 58 is a substantially circular flat plate member having a central axis A2. A through hole 63 (FIG. 6, FIG. 7) and a plurality of mounting holes 64 (FIG. 6) are formed in the mounting flange 58. The through hole 63 is arranged in the center of the mounting flange 58. The mounting holes 64 are arranged around the through hole 63 at equal intervals in the circumferential direction. The mounting flange 58 is detachably fastened to the wrist flange 30b by fasteners such as bolts inserted into the mounting holes 64. In this way, the hand base 52 is fixed to the wrist flange 30b.

The support platform 60 is arranged to be spaced from the mounting flange 58 in the axially downward direction and is arranged to be substantially parallel to the mounting flange 58. The support platform 60 is a flat plate member having the same outer shape (i.e., substantially circular) as the mounting flange 58. Through holes 66 and 68 (Fig. 6 and Fig. 7) are formed in the support platform 60. The through hole 66 is arranged at the center of the support platform 60. In the present embodiment, a total of four through holes 68 are arranged to be arranged at a predetermined angle (=45°) in the circumferential direction.

Each of the pillars 62 extends straight in the axial direction between the mounting flange 58 and the support platform 60. In the present embodiment, a total of two pillars 62 are arranged at substantially equal intervals (90° intervals) in the circumferential direction. The mounting flange 58, the support platform 60, and the pillars 62 are fixed to each other by bolt fastening or welding, thereby forming a one-piece hand base 52.

The suction hand 54 is provided on the hand base 52, and has an arm 70, a slider 72, a second force applying mechanism 74, and a suction pad 76. The slider 72 is provided on the hand base 52 in a manner that it can slide in the axial direction. A through hole 72a (FIG. 6) is formed in the center of the slider 72. In addition, a through hole (not shown) can also be formed in the slider 72, and the column 62 can be inserted through the through hole so as to slide relatively, thereby fitting the slider 72 in the column 62 in a manner that it can reciprocate in the axial direction. In this case, the reciprocating movement of the slider 72 can be guided by the column 62.

The arm 70 (second arm) is a cylindrical member having a central axis A3 and extending in the axial direction. In the present embodiment, the axis A3 is substantially consistent with (or parallel to) the axes A1 and A2. The arm 70 has a fixed arm portion 78 and a movable arm portion 80. The fixed arm portion 78 is cylindrical and fixed to the hand base 52. More specifically, the fixed arm portion 78 is inserted and fixed to the through hole 63 (FIG. 6, FIG. 7) formed in the mounting flange 58, and is pulled out axially upward of the mounting flange 58.

The movable arm 80 is cylindrical and is fitted in the fixed arm 78 in a manner that allows sliding along the axis A3. In this embodiment, the movable arm 80 has a diameter slightly larger than that of the fixed arm 78, and is slidably fitted into the fixed arm 78 inside the movable arm 80. In addition, the inner peripheral surface of the movable arm 80 and the outer peripheral surface of the fixed arm 78 can also be in airtight surface contact in a relatively slidable manner. In addition, the movable arm 80 can be inserted through the through hole 66 formed in the support table 60 in a relatively slidable manner (Figures 6 and 7).

The movable arm 80 is fixed to the slider 72 at its axial end 80a. More specifically, the upper end 80a of the movable arm 80 is inserted and fixed to the through hole 72a (Fig. 6) formed in the slider 72, and reciprocates in the axial direction together with the slider 72. The interior of the movable arm 80 and the interior of the fixed arm 78 are connected to each other, defining a flow path of external air described later.

The suction pad 76 is a hollow flexible member having a central axis A3 and is mounted on the axially lower end 80b of the movable arm 80. The suction pad 76 has a front end face 82 and a suction port 84 (FIG. 5, FIG. 7). As shown in FIG. 5, the front end face 82 defines the suction port 84 at its center. The suction port 84 is a substantially circular hole having a central axis A3 and is open axially downward. In addition, the suction pad 76 can be formed into a corrugated tube shape, thereby being able to be stretched and contracted in the axial direction.

The second force-applying mechanism 74 applies force in such a manner that the movable arm 80 and the suction pad 76 advance axially downward. In this embodiment, the force-applying mechanism 74 has a pneumatic or hydraulic cylinder 86. More specifically, the cylinder 86 has a hollow cylinder body 86a and a cylinder shaft 86b housed in the cylinder body 86a in a reciprocating manner. The front end of the cylinder shaft 86b is fixed to the axially upward surface of the slider 72.

The interior of the cylinder body 86a is fluidically connected to the fluid supply device FD (not shown) via the flow tube PT. The control device 20 can automatically control the pressure P in the cylinder body 86a by controlling the fluid supply device FD. The cylinder body 86 pushes the cylinder shaft 86b axially downward by the pressure P supplied to the cylinder body 86a, thereby applying force to the slider 72, the movable arm 80 and the suction pad 76 axially downward. FIG. 4 shows a state in which the force applying mechanism 74 (cylinder body 86) causes the suction pad 76 to move forward axially downward, while FIG. 8 shows a state in which the movable arm 80 and the suction pad 76 move backward axially upward. In this way, the arm 70 causes the suction pad 76 to move forward and backward along the axis A3.

The suction hand 56 is disposed on the hand base 52. In this embodiment, the suction hand 56 has a total of two large suction hands 88 and 90, and a total of two small suction hands 92 and 94. As shown in FIG. 5 , in this embodiment, the large suction hands 88 and 90 and the small suction hands 92 and 94 are arranged in an alternating manner around the axis A3 (i.e., the axes A1 and A2) at a prescribed angle θ1=45°.

The large suction hand 88 is a hollow member having a central axis A4, and is inserted and fixed in a through hole 68 formed in the support table 60 (FIG. 6, FIG. 7). Specifically, the large suction hand 88 has a suction pad 96, an arm 98, and a first force applying mechanism 100. The suction pad 96 is a hollow flexible member having a central axis A4, and is mounted on the front end of the arm 98. Specifically, the suction pad 96 has a front end surface 102 and a suction port 104 (FIG. 5, FIG. 7).

The front end surface 102 defines a suction port 104 at its center. The suction port 104 (first suction port) is a substantially circular hole having a center axis A4 and having a first opening size R1. In addition, the suction pad 96 is formed into a corrugated tube shape, thereby also being configured to be axially stretchable. In addition, the suction pad 96 may also have a higher flexibility than the above-mentioned suction pad 76. In addition, the suction pad 96 may also be composed of a material different from that of the suction pad 76 (rubber, resin, etc.).

The arm 98 (first arm) is a hollow member having a central axis A4 and is fixed to the hand base 52. More specifically, the arm 98 has a cylinder 106 and a shaft 108. The cylinder 106 is hollow and is inserted through the through hole 68 (FIG. 6 and FIG. 7) fixed to the support 60. The shaft 108 is hollow and is accommodated inside the cylinder 106 in a manner that it can move forward and backward in the direction of the axis A4. The suction pad 96 is mounted on the front end of the shaft 108.

The first force applying mechanism 100 applies force to the shaft 108 and the adsorption pad 96 in an axially downward direction. In this embodiment, the force applying mechanism 100 has a spring SP (not shown) built into the cylinder 106. The spring SP is inserted between the inner wall of the cylinder 106 and the shaft 108, and the force applying mechanism 100 applies force to the shaft 108 and the adsorption pad 96 by the elastic force of the spring SP.

Thus, the urging mechanism 100 is a first type of urging mechanism that generates urging force by the spring SP, while the urging mechanism 74 is a second type of urging mechanism that generates urging force by the cylinder 86. By the action of the urging mechanism 100, the arm 98 moves the suction pad 96 forward and backward along the axis A4 of the suction port 104.

The large suction hand 90 is a hollow member having a central axis A5, and is inserted and fixed in a through hole 68 formed in the support table 60. The large suction hand 90 has the same structure as the large suction hand 88, and is arranged to be rotationally symmetrical with the large suction hand 88 based on the axis A3. Specifically, the large suction hand 90 has a suction pad 96, an arm 98 (cylinder body 106, shaft 108) and a force-applying mechanism 100, and the suction pad 96 defines a suction port 104 having an axis A5. By the action of the force-applying mechanism 100 (spring SP) provided in the cylinder body 106, the arm 98 of the large suction hand 90 causes the suction pad 96 to move forward and backward along the axis A5 of the suction port 104.

The small suction hand 92 is a hollow member having a central axis A6 and is inserted and fixed in a through hole 68 formed in the support table 60. The small suction hand 92 has a suction pad 110, the arm 98 (cylinder body 106, shaft 108) and a force applying mechanism 100. The cylinder body 106 of the arm 98 is inserted and fixed in the through hole 68 of the support table 60, and the suction pad 110 is installed at the front end of the shaft 108 of the arm 98.

The suction pad 110 is a hollow flexible member having a central axis A6, and has a front end surface 112 and a suction port 114 (FIG. 5, FIG. 7). The front end surface 112 defines the suction port 114 at its center. The suction port 114 (second suction port) is a substantially circular hole having a central axis A6, and has a second opening size R2 smaller than the first opening size R1 (R2＜R1).

In addition, the suction pad 110 is formed into a corrugated tube shape, thereby also being configured to be axially stretchable. In addition, the suction pad 110 may also have a higher flexibility than the above-mentioned suction pad 76. In addition, the suction pad 110 may also be composed of a material different from that of the suction pad 76 (rubber, resin, etc.). By the action of the force-applying mechanism 100 (spring SP) disposed in the cylinder body 106, the arm 98 of the small suction hand 92 causes the suction pad 110 to move forward and backward along the axis A6 of the suction port 114.

The small suction hand 94 is a hollow component having a central axis A7, and is inserted and fixed in a through hole 68 formed in the support table 60. The small suction hand 94 has the same structure as the small suction hand 92, and is arranged to be rotationally symmetrical with the small suction hand 92 based on the axis A3. Specifically, the small suction hand 94 has a suction pad 110, an arm 98 (cylinder body 106, shaft 108) and a force-applying mechanism 100, and the suction pad 110 defines a suction port 114 having an axis A7. By the action of the force-applying mechanism 100 (spring SP) provided in the cylinder body 106, the arm 98 of the small suction hand 94 causes the suction pad 110 to move forward and backward along the axis A7.

As described above, in the present embodiment, the suction hand 56 has a plurality of (specifically, 2) suction ports 104 and a plurality of (specifically, 2) suction ports 114 arranged around the suction port 84 in a manner arranged in directions around the axes A1, A2, and A3, as shown in FIG. 5. Moreover, the suction ports 104 and the suction ports 114 are arranged in the circumferential direction in a manner alternately arranged around the axes A1, A2, and A3 at a prescribed angle θ1 (=90°). In addition, in the present embodiment, the axis A3 of the suction hand 54, the axes A4 and A5 of the large suction hands 88 and 90, and the axes A6 and A7 of the small suction hands 92 and 94 are substantially parallel to each other.

Referring again to FIG. 1 and FIG. 2 , the visual sensor 14 photographs the object W to be held by the robot 50. Specifically, the visual sensor 14 is, for example, a 3D visual sensor, and has an imaging sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), an optical lens such as a focusing lens, and an image processing processor. The visual sensor 14 is arranged at an imaging position αi where the object can be included in the field of view, and supplies the image data ID (3D point group image data, distance image data, etc.) of the photographed object to the control device 20. In addition, the visual sensor 14 can be fixed at a designated imaging position αi, or can also be fixed to the wrist flange 30b or the robot 50 (for example, the hand base 52), and moved to the imaging position αi by the moving mechanism 34.

Referring to FIG. 2 , the first type of exhaust device 16 is fluidically connected to the inside of the suction hand 54 so as to generate an air flow in the suction hand 54 by sucking in the outside air through the suction port 84 of the suction hand 54. Hereinafter, an example of the first type of exhaust device 16 will be described with reference to FIG. 9 . In this embodiment, the first type of exhaust device 16 utilizes the so-called Coanda effect to generate an air flow by sucking in the outside air from the suction port 84 of the suction hand 54.

Specifically, the exhaust device 16 has a gas injection device 120 and an airflow generating mechanism 122. The airflow generating mechanism 122 has a gas inlet 122a, a spiral flow path 122b, a gas outlet 122c, and a gas suction port 122d. The gas injection device 120 introduces a gas jet D1 into the gas inlet 122a. The jet D1 flowing into the gas inlet 122a flows in the spiral flow path 122b formed inside the airflow generating mechanism 122, and is ejected from the gas outlet 122c as a jet D1'.

The flow of the jet D1 in the airflow generating mechanism 122 generates a Coanda effect, thereby generating an airflow D2 sucked into the airflow generating mechanism 122 from the gas suction port 122d. The gas suction port 122d is fluidically connected to the inside of the suction hand 54 (specifically, the opening end on the axial side of the fixed arm 78) through the flow tube 124, and can generate an airflow of sucking outside air from the suction port 84 of the suction hand 54 through the airflow D2 generated as described above.

In addition, the exhaust device 16 is not limited to the form of the airflow generating mechanism 122 utilizing the Coanda effect, and may be, for example, a fan with blades and a motor for rotating the fan (such as a suction device such as a so-called vacuum cleaner). Alternatively, the exhaust device 16 may be composed of a Venturi tube mechanism assembly formed by connecting a plurality of Venturi tube type negative pressure generating mechanisms described later.

When the exhaust device 16 is activated with the suction port 84 of the suction hand 54 opened, the suction hand 54 is configured to be able to suck in a maximum flow rate E1 of external air from the suction port 84. On the other hand, when the exhaust device 16 is activated with the suction port 84 closed, the suction hand 54 forms a negative pressure ρ1 inside the suction pad 76 (i.e., the suction port 84).

The second exhaust devices 18A, 18B, 18C and 18D are fluidly connected to the inside of the large suction hands 88 and 90 and the small suction hands 92 and 94, respectively, to form negative pressure inside the large suction hands 88 and 90 and the small suction hands 92 and 94. The second exhaust devices 18A, 18B, 18C and 18D generate airflow by a different mechanism from the first exhaust device 16.

Hereinafter, referring to FIG. 10 , an example of the second type of exhaust devices 18A, 18B, 18C and 18D will be described. The exhaust devices 18A, 18B, 18C and 18D each have a gas injection device 130 and a negative pressure generating mechanism 132. The negative pressure generating mechanism 132 has a gas inlet 132a, a venturi tube flow path 132b, a gas outlet 132c and a gas suction port 132d. A nozzle 132e is formed at a portion where the venturi tube flow path 132b and the gas suction port 132d are connected to narrow the venturi tube flow path 132b.

The gas injection device 130 introduces a gas jet G1 into the gas inlet 132a. The jet G1 flowing into the gas inlet 132a flows in the venturi tube flow path 132b, is rapidly compressed by the nozzle 132e, and is ejected from the gas outlet 132c as a jet G1'. The flow of the jet G1 rapidly compressed by the nozzle 132e generates a venturi effect, thereby generating a relatively large negative pressure at the gas suction port 132d. As a result, an air flow G2 is generated and sucked into the gas suction port 132d. In addition, the gas suction port 132d may have an opening size smaller than the above-mentioned gas suction port 122d.

The gas inlet 132d of the exhaust devices 18A, 18B, 18C, and 18D are fluidly connected to the inside of the large suction hands 88 and 90, and the small suction hands 92 and 94 through the flow pipe 134. By the airflow G2 generated as described above, a relatively large negative pressure can be formed inside each of the large suction hands 88 and 90, and the small suction hands 92 and 94. In addition, at least one of the exhaust devices 18A, 18B, 18C, and 18D is not limited to the form having the negative pressure generating mechanism 132 using the Venturi effect, and may also be a vacuum pump, for example.

When the exhaust devices 18A and 18B are activated with the suction ports 104 of the large suction hands 88 and 90 closed, the large suction hands 88 and 90 are configured so as to form a negative pressure ρ2 (|ρ2|≫|ρ1|) much greater than the negative pressure ρ1 in the interior of the respective suction pads 96 (i.e., the suction ports 104). On the other hand, when the exhaust devices 18A and 18B are activated with the suction ports 104 open, the large suction hands 88 and 90 inhale the outside air at a maximum flow rate E2 (E2≪E1) much less than the maximum flow rate E1 from the respective suction ports 104.

Similarly, when the exhaust devices 18C and 18D are activated with the suction ports 114 of the small suction hands 92 and 94 closed, the small suction hands 92 and 94 are constructed in such a way that a negative pressure ρ3 (｜ρ3｜≫｜ρ1｜) much greater than the above-mentioned negative pressure ρ1 can be formed inside their respective suction pads 110 (i.e., suction ports 114).

In addition, the negative pressure ρ3 may be substantially the same as the negative pressure ρ2 (ρ3≒ρ2), or may be less than (or greater than) the negative pressure ρ2 (ρ3＜ρ2 or ρ3＞ρ2). On the other hand, when the exhaust devices 18C and 18D are activated with the suction port 114 opened, the small suction hands 92 and 94 inhale the outside air from their respective suction ports 114 at a maximum flow rate E3 (E3≪E1) which is much less than the maximum flow rate E1.

2 , the control device 20 controls the movement of the robot 12 by operating the moving mechanism 34 to move the robot 50 so as to perform a holding action of holding an object with the robot 50. More specifically, the control device 20 is a computer having a processor 40, a memory 42, and an I/O interface 44.

The processor 40 has a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), etc., and is communicatively connected to the memory 42 and the I/O interface 44 via a bus 46. The processor 40 communicates with the memory 42 and the I/O interface 44, and performs calculation processing for executing the holding action described later. The memory 42 has a RAM (Random Access Memory) or a ROM (Read-Only Memory), etc., and temporarily or permanently stores various data. The memory 42 can also be a computer-readable recording medium such as a semiconductor memory, a magnetic recording medium, or an optical recording medium.

The I/O interface 44 has, for example, an Ethernet (registered trademark) port, a USB port, an optical fiber connector, or an HDMI (High Definition Multimedia Interface) (registered trademark) terminal, and communicates data with an external device by wire or wirelessly under the command from the processor 40. The servo motor 32, the visual sensor 14, the exhaust device 16, and 18A to 18D are connected to the I/O interface 44 by wire or wireless communication.

As shown in FIG1 , a robot coordinate system C1 and a tool coordinate system C2 are set for the robot 12. The robot coordinate system C1 is a coordinate system for automatically controlling the movements of the movable components of the robot 12 (i.e., the rotating body 24, the lower arm 26, the upper arm 28, the wrist base 30a, the wrist flange 30b, and the manipulator 50). In the present embodiment, the robot coordinate system C1 is fixed to the robot base 22 with its origin arranged at the center of the robot base 22 and its z-axis being parallel (specifically, identical) to the rotation axis of the rotating body 24.

On the other hand, the tool coordinate system C2 is a coordinate system that specifies the position of the manipulator 50 in the robot coordinate system C1. For example, the tool coordinate system C2 is fixed to the manipulator 50 in such a way that its origin (so-called TCP (Tool Center Position)) is located at the center of the suction port 84 of the suction hand 54 and its z-axis is parallel to (specifically, coincident with) the axis A3.

When the robot 50 is moved, the processor 40 of the control device 20 sets the tool coordinate system C2 in the robot coordinate system C1, and generates instructions to the servo motors 32 of the robot 12 in such a manner that the robot 50 is positioned at the position represented by the set tool coordinate system C2. In this way, the control device 20 can position the robot 50 at any position in the robot coordinate system C1. In addition, in this specification, "position" may represent both position and posture.

Next, the function of the robot system 10 is described. In this embodiment, as shown in FIG. 11 , various articles W of different sizes, shapes, masses or materials are dispersed and stacked in a container H. As an example, the article W is a fixed-shaped packaging box that contains goods (food, medicine, groceries, etc.) and is made of paper or resin and has a smooth or uneven outer surface. Furthermore, as another example, the article W is an indeterminate packaging bag (vinyl bag, wrapping paper, etc.) with higher flexibility than a fixed-shaped packaging box and is made of paper or resin.

The processor 40 of the control device 20 operates the moving mechanism 34 to move the robot 50, and performs the holding operation of holding the article W in the container H and taking it out of the container H. The following is a description of the process of the article holding operation with reference to FIG. 12. When the processor 40 receives the operation start instruction from the operator, the upper controller or the computer program PG, it starts the process shown in FIG. 12. In addition, the processor 40 can also execute the process shown in FIG. 12 according to the computer program PG pre-stored in the memory 42.

In step S1, the processor 40 uses the visual sensor 14 to photograph the object W. Specifically, the processor 40 activates the visual sensor 14 disposed at the photographing position αi to photograph the object W in the container C. The processor 40 obtains the image data ID (e.g., 3D point group image data or distance image data) of the photographed object W from the visual sensor 14.

In step S2, the processor 40 obtains the surface size SZ of the object W to be held. Specifically, the processor 40 analyzes the image data ID obtained in the previous step S1, and determines the object W to be held from the multiple objects W shown in the image ID. At this time, the processor 40 can also determine the object W with the largest z coordinate (in other words, the height in the vertical direction) of the robot coordinate system C1 as the object to be held. Then, based on the image data ID, the processor 40 specifies the upward surface Ws of the object W to be held, and obtains the size SZ (for example, the surface area) of the surface Ws.

In step S3, the processor 40 determines whether the suction hand 54 is used in the holding action of holding the object W. For example, the processor 40 determines whether the surface size SZ obtained in the previous step S2 is smaller than the opening size R2 of one suction port 114 of the small suction hands 92 and 94.

Here, if the surface size SZ is smaller than the opening size R2 of one suction port 114, even if the front end surface 112 of the suction pad 110 is brought into surface contact with the surface Ws of the article W, a gap is generated between the front end surface 112 and the surface Ws. In this case, the negative pressure ρ3 cannot be formed inside the suction pad 110, and the article W cannot be sucked into the suction port 114. This is also true for the suction ports 104 of the large suction hands 88 and 90 having a larger opening size R1.

In this case, it is effective to use the suction hand 54 to suck and hold the article W. In step S3, the processor 40 compares the surface size SZ obtained in step S2 with the opening size R2 of one suction port 114 (for example, the surface area represented by the opening size R2). When the surface size SZ is smaller than the opening size R2, the processor 40 determines that the suction hand 54 is used (that is, YES). When the processor 40 determines that it is YES, it proceeds to step S5. On the other hand, when the processor 40 determines that it is NO, it proceeds to step S4.

In step S4, the processor 40 executes the plan of the holding action of the suction hand 56. Referring to Figure 13, the step S4 is explained. In step S11, the processor 40 determines the number N1 of suction ports 104 and the number N2 of suction ports 114 used for the holding action based on the surface size SZ obtained in the most recent step S2. Here, in the present embodiment, a plurality of suction modes, each of which specifies the number N1 of suction ports 104 and the number N2 of suction ports 114 used for the holding action, are pre-set. An example of the suction mode is shown in Figure 14. In the example shown in Figure 14, 7 suction modes 1 to 7 are specified. In Figure 14, the "N1" row represents the number N1 of suction ports 104, and the "N2" row represents the number N2 of suction ports 114.

For example, in suction mode 4, since N1=0 and N2=2, it is specified that two suction ports 114 (i.e., small suction hands 92 and 94) are used to perform the holding action. On the other hand, in suction mode 7, since N1=2 and N2=2, it is specified that two suction ports 104 (i.e., large suction hands 88 and 90) and two suction ports 114 (i.e., small suction hands 92 and 94) are used to perform the holding action.

In this embodiment, a data table DT1 of the adsorption mode as shown in FIG. 14 is prepared in advance and stored in the memory 42. In step S11, the processor 40 selects one of the plurality of adsorption modes 1 to 7 according to the surface size SZ obtained most recently, thereby determining the number N1 and the number N2. Here, the range of the surface size SZ is associated with each of the adsorption modes 1 to 7.

For example, the range of _SZn ≦SZ<SZn ₊₁ is associated with one adsorption mode n (n=1, 2, 3, ...). In this case, the threshold _SZn can also be pre-set based on the product of the number N1 specified by the adsorption mode n and the opening size R1 (surface area) of the adsorption port 104 (=N1×R1), and the sum (=N1×R1+N2×R2) of the number N2 specified by the adsorption mode n and the opening size R2 (surface area) of the adsorption port 114 (=N2×R2).

In this way, the range of the surface size SZ is associated with each of the plurality of adsorption patterns n. The processor 40 applies the most recently acquired surface size SZ to the data table DT1, and selects one adsorption pattern n corresponding to the surface size SZ from the plurality of adsorption patterns 1 to 7. In this way, the processor 40 can determine the number N1 and N2 specified by the selected adsorption pattern n as the number N1 of the adsorption ports 104 and the number N2 of the adsorption ports 114 used for the holding action.

In step S12, the processor 40 starts to hold the object W with the suction hand 56. The following describes the case where the processor 40 selects suction mode 3 (N1=1, N2=2) shown in FIG. 14 in the previous step S11. In this case, the processor 40 activates the exhaust device 18B connected to the large suction hand 90 and the exhaust device 18C connected to the small suction hand 92.

Furthermore, the processor 40 operates the moving mechanism 34 to move the robot 50 toward the object W to be held. As a result, as shown in FIG15 , the front end face 102 of the suction pad 96 of the large suction hand 90 and the front end face 112 of the suction pad 110 of the small suction hand 92 are pressed against the surface Ws of the object W and are in airtight surface contact with the surface Ws. At this time, the front end faces 102 and 112 can be effectively in surface contact with the surface Ws by the flexible deformation of the suction pads 96 and 110 in the axial direction. In this way, a closed space is defined inside the suction pads 96 and 110.

As a result, negative pressures ρ2 and ρ3 are formed in the closed space defined inside the suction pads 96 and 110 respectively by the exhaust devices 18B and 18C. The object W is airtightly adsorbed to the suction ports 104 and 114 by the negative pressures ρ2 and ρ3 thus formed in the closed space (i.e., the suction ports 104 and 114). In this way, the object W is adsorbed and held by the large suction hand 90 and the small suction hand 92.

Here, during the holding action of step S12, when the object W is held by the suction pads 96 and 110, the object W can be lifted upward toward the hand base 52 by the axial deformation of the suction pads 96 and 110. At this time, the suction pad 76 of the suction hand 54 can contact the surface Ws of the object W.

In step S13, the processor 40 determines whether the gripping action fails. For example, the robot system 10 is further provided with a pressure sensor PS (not shown) that can detect the negative pressures ρ2 and ρ3 formed inside the large suction hands 88 and 90, and the small suction hands 92 and 94, respectively. The processor 40 monitors the negative pressure ρ2 of the large suction hand 90 and the negative pressure ρ3 of the small suction hand 92 while the robot hand 50 moves toward the gripping object in the gripping action.

When at least one of the negative pressure ρ2 of the large suction hand 90 and the negative pressure ρ3 of the small suction hand 92 does not exceed the prescribed threshold ρ _th , the processor 40 determines that it is yes and proceeds to step S14. On the other hand, when both the negative pressure ρ2 of the large suction hand 90 and the negative pressure ρ3 of the small suction hand 92 exceed the threshold ρ _th , the processor 40 determines that it is no and proceeds to step S17.

In step S14, the processor 40 determines whether the number of times Nf of failed gripping actions has reached a specified number of times Nf _th . Here, the processor 40 repeats the loop of steps S11 to S16 when it is determined to be yes in step S13 and when it is determined to be no in steps S14 and S15. During the period of repeating the loop of steps S11 to S16, the processor 40 counts the number of times Nf of the times determined to be yes in step S13. In addition, in step S14, when the number of times Nf reaches a specified number of times Nf _th (for example, Nf _th = 3 times), the processor 40 determines to be yes and returns to step S1 in FIG. 12 . On the other hand, when it is determined to be no, it proceeds to step S15.

In step S15, the processor 40 determines whether the numbers N1 and N2 determined in the most recent step S11 are the numbers of adsorption mode 1 in FIG14 (N1=0, N2=1). When the processor 40 determines that it is yes, it proceeds to step S5 in FIG12, and when it determines that it is no, it proceeds to step S16.

In step S16, the processor 40 executes the retreat action of the robot 12. Specifically, the processor 40 operates the moving mechanism 34 of the robot 12 to make the robot 50 retreat a predetermined distance from the nearest position determined as yes in step S13 to the positive direction of the z-axis of the robot coordinate system C1 (i.e., directly upward). As a result, the robot 50 retreats to the outside of the container.

Afterwards, the processor 40 returns to step S11 and determines the number N1 and the number N2 again. Here, in this embodiment, when step S11 is executed after step S16, the adsorption mode n-1 is selected by pushing the identification number "n" of the adsorption mode n selected in the previous step S11 forward by one. That is, the processor 40 selects adsorption mode n (n=2, 3, 4, ...) in step S11, and then, after executing steps S12 to S16, executes step S11 again. In this case, the processor 40 selects adsorption mode n-1.

To be more specific, assume that in the first step S11, adsorption mode 3 (N1=1, N2=1) is selected, and then steps S12 to S16 are executed, and then the second step S11 is executed. In this case, the processor 40 selects adsorption mode 2 (N1=1, N2=0) in the second step S11.

The total number Ns (= N1 + N2) of the number N1 and N2 of adsorption mode 3 (the first adsorption mode) is 2. On the other hand, the total number Ns of the number N1 and N2 of adsorption mode 2 (the second adsorption mode) is 1. That is, in this case, when the holding action performed according to adsorption mode 3 selected in the first step S11 fails, the processor 40 selects adsorption mode 2 whose total number Ns of the number N1 and N2 is less than that of adsorption mode 3, and performs the holding action again in step S12 according to adsorption mode 2. In addition, after selecting adsorption mode 7 or 6 in the first step S11, the same is true when executing the second step S11. The processor 40 selects adsorption mode 6 or 5 whose total number Ns is reduced by 1.

On the other hand, when the adsorption mode 5 is selected in the first step S11 and the second step S11 is executed thereafter, the processor 40 selects the adsorption mode 4 in the second step S11. In this case, the number N1 of the adsorption ports 104 is specified to be 2 in the adsorption mode 5 (the first adsorption mode), and the number N2 of the adsorption ports 114 is specified to be 0.

Furthermore, in suction mode 4 (second suction mode), the number of suction ports 104 N1=0 is specified, and on the other hand, the number of suction ports 114 N2=2 is specified. That is, in this case, when the gripping action performed according to suction mode 5 selected in the first step S11 fails, the processor 40 selects suction mode 4 in which the opening size R of the suction port used for the gripping action becomes smaller although the total number Ns is the same, and the gripping action is performed again in step S12 according to the suction mode 4. In addition, after suction mode 4 or 2 is selected in the first step S11, the second step S11 is executed in the same manner, and the processor 40 selects suction mode 3 or 1 in which the opening size R is smaller although the total number Ns is the same.

As described above, when the processor 40 executes step S11 after step S16, it selects the adsorption mode n-1 and executes step S12 again according to the mode n-1. At this time, the processor 40 can switch the adsorption ports 104 and 114 used for the holding action from the adsorption mode n to the adsorption mode n-1 by rotating the robot 50 around the axis A1 (i.e., the axes A2 and A3).

For example, in the first step S12, the large suction hands 88 and 90 in FIG. 5 perform a gripping action according to the suction mode 5 (N1=2, N2=0) in FIG. 14. Then, in the second step S12, the processor 40 performs a gripping action according to the suction mode 4 (N1=0, N2=2) with the small suction hands 92 and 94. In this case, the processor 40 can switch from the suction mode 5 to the suction mode 4 by rotating the robot hand 50 around the axis A1 by an angle θ1 (90°).

Referring to FIG. 13 again, when the determination in step S13 is negative, in step S17, the processor 40 continues the holding action. Specifically, as a holding action, the processor 40 causes the robot 50 that holds the object W in the container H by the suction hand 56 (specifically, the large suction hand 90 and the small suction hand 92) to retreat in a specified removal direction DR1 as shown in FIG. The removal direction DR1 is, for example, defined as the positive direction of the z-axis of the robot coordinate system C1 (i.e., directly upward). In this way, the object W is taken out of the container H. During the holding action, the processor 40 continues to monitor the negative pressures ρ2 and ρ3 detected by the pressure sensor PS.

In step S18, the processor 40 determines whether the gripping action fails, similarly to the above step S13. Specifically, when at least one of the negative pressures ρ2 and ρ3 detected by the pressure sensor PS is lower than a predetermined threshold, the processor 40 determines that it is a failure and proceeds to step S1 in FIG. 12. On the other hand, when the processor 40 determines that it is a failure, it proceeds to step S19.

In step S19, the processor 40 determines whether the holding action is completed. Specifically, the processor 40 determines that it is yes when the robot 50 retreats from the position when the suction hand 56 holds the object W by suction (specifically, it is determined as no in step S13) to the predetermined position α1 in the removal direction DR1. The position α1 can be defined as a position separated by a predetermined distance Δ from the opening end He (Figure 11) of the container H in the removal direction DR1 (the positive direction of the z-axis of the robot coordinate system C1). The distance Δ is, for example, pre-set to a distance greater than the length of the longest object among the various objects W dispersedly stacked in the container H.

When the processor 40 determines that it is yes, it proceeds to step S6 in FIG. 12 , and when it determines that it is no, it returns to step S18 . When the processor 40 determines that it is yes in step S19 , the end We ( FIG. 15 ) of the object W held by the robot 50 in the opposite direction to the taking-out direction DR1 is arranged at a position spaced apart from the opening end He ( FIG. 11 ) of the container H in the taking-out direction DR1 by a distance Δ.

Referring again to Fig. 12, when the judgment is yes in step S3 or step S15 in Fig. 13, in step S5, the processor 40 executes the scheme of the holding action of the suction hand 54. Referring to Fig. 16, the step S5 is explained. In step S21, the processor 40 executes the holding action of the object W of the holding object with the suction hand 54.

Specifically, the processor 40 first activates the exhaust device 16 to start the action of sucking outside air from the suction port 84 of the suction hand 54. Then, the processor 40 operates the moving mechanism 34 to move the robot hand 50 toward the object W to be held. As a result, as shown in FIG. 17 , the front end surface 82 of the suction pad 76 contacts the object W to be held, and the object W is sucked into the suction port 84 by the flow of outside air sucked into the suction port 84 at the maximum flow rate E1.

Here, in this embodiment, the process of step S5 shown in FIG. 16 is executed when the determination in the above step S3 is yes (i.e., the surface size SZ of the object W is smaller than the opening size R2 of the suction port 114), or when the determination in step S15 in FIG. 13 is yes (i.e., the holding action in suction mode 1 (only one suction port 114) fails). Therefore, when executing step S5, the surface size SZ of the object W to be held may be so small that it cannot be sucked by one suction port 114.

Therefore, when the article W is sucked into the suction port 84, a gap G may be formed between the front end surface 82 of the suction pad 76 and the article W, and a large amount of external air is continuously sucked into the suction port 84 through the gap G. By the flow of such external air, the suction hand 54 can continuously suck and hold the article W with a small surface size SZ in the suction port 84.

In addition, due to the formation of the above-mentioned gap G, the inside of the suction pad 76 in the state shown in FIG. 17 cannot become a closed space, and therefore, the negative pressure ρ1' formed inside the suction pad 76 at this time is much smaller than the above-mentioned negative pressures ρ2 and ρ3 (｜ρ1'｜≪｜ρ2｜ and｜ρ3｜). In other words, the suction hand 54 does not suck and hold the object W by the negative pressure ρ1' of the suction pad 76, but sucks and holds the object W by the flow of the outside air sucked into the suction port 84. In this way, the suction hand 54 holds the object W by a "suction method" different from the "suction method" of the above-mentioned suction hand 56.

In step S22, the processor 40 determines whether the holding action fails. For example, the robot system 10 is further provided with a flow sensor FS (not shown) that can detect the flow rate E of the external air flowing inside the suction hand 54 (specifically, the movable arm 80 and the fixed arm 78). The processor 40 monitors the flow rate E detected by the flow sensor FS while the robot hand 50 moves toward the holding object in the holding action. When the monitored flow rate E does not change in a manner lower than the specified threshold E _th , the processor 40 determines that it is yes and proceeds to step S23. On the other hand, when the flow rate E changes in a manner lower than the threshold E _th , the processor 40 determines that it is no and proceeds to step S25.

In step S23, the processor 40 determines whether the number of times Nf of failed gripping actions has reached the specified number _Nfth , similar to the above step S14. When the processor 40 determines that it is yes, it proceeds to step S1 in FIG. 12. On the other hand, when the processor 40 determines that it is no, it proceeds to step S24. In addition, the number _Nfth used as a threshold reference in step S23 may be the same as that in step S14, or may be different. In step S24, the processor 40 returns to step S21 after executing the retreat action of the robot 12, similar to the above step S16.

On the other hand, if the determination in step S22 is negative, in step S25, the processor 40 continues the holding action as in step S17, and as shown in FIG17, the robot 50 holding the article W by the suction hand 54 is made to retreat in the taking-out direction DR1. During the holding action, the processor 40 continues to monitor the flow rate E detected by the flow sensor FS.

In step S26, the processor 40 determines whether the holding action has failed, similarly to the above step S22. When the processor 40 determines that it is yes, it proceeds to step S1 in FIG. 12, and when it determines that it is no, it proceeds to step S27. In step S27, the processor 40 determines whether the holding action has ended (i.e., whether the robot 50 has retreated to position α1), similarly to the above step S19, and when it determines that it is yes, it proceeds to step S6 in FIG. 12, and when it determines that it is no, it returns to step S26.

Referring again to FIG. 12 , in step S6, the processor 40 performs a transporting operation to transport the article W taken out by the robot 50 to the designated storage location SL and place it in the storage location SL. Specifically, the processor 40 operates the moving mechanism 34 to move the robot 50 holding the article W from the above-mentioned position α1 toward a direction DR2 that intersects (e.g., is orthogonal to) the taking-out direction DR1 in the holding operation. For example, the direction DR2 is defined as a direction along the x-y plane of the robot coordinate system C1 (i.e., a horizontal direction).

Furthermore, when the processor 40 moves the robot 50 to the designated position α2 on the storage location SL, the moving mechanism 34 stops, and then the robot 50 moves to release the gripped object W. For example, when executing step S6 after step S4, the processor 40 stops the exhaust devices 18B and 18C to eliminate the negative pressure ρ2 inside the large suction hand 90 and the negative pressure ρ3 inside the small suction hand 92.

Alternatively, when executing step S6 after step S5, the processor 40 stops the action of sucking in the outside air from the suction port 84 by stopping the exhaust device 16. As a result, the robot 50 can release the gripped object W and place it in the storage place SL. In step S7, the processor 40 determines whether the operation of taking out all the objects W in the storage area H is completed. If the processor 40 determines that it is yes, it ends the process shown in FIG. 12. On the other hand, if the processor determines that it is no, it returns to step S1.

As described above, in the present embodiment, the robot system 10 comprises: a robot 12 having a manipulator 50 including a first suction port 104 and a second suction port 114 having opening sizes R1 and R2 different from each other; and a control device 20 which moves the robot 12 to move the manipulator 50 to perform a holding action of holding the object W with the manipulator 50.

The control device 20 (specifically, the processor 40) obtains the surface size SZ of the object W to be grasped (step S2), and determines the number N1 of the first suction ports 104 and the number N2 of the second suction ports 114 used for the grasping operation based on the obtained surface size SZ (step S11). According to this configuration, since the number N1 and N2 of the surface size SZ suitable for the object W can be determined, the suction ports 104 with the number N1 and the suction ports 114 with the number N2 can be determined to effectively grasp objects W of various sizes. In addition, the operation of grasping and lifting objects W of various sizes can be automated.

In addition, in the present embodiment, a plurality of adsorption patterns 1 to 7 (FIG. 14) are pre-set, each of which specifies the number N1 of the first adsorption ports 104 and the number N2 of the second adsorption ports 114. Furthermore, the control device 20 determines the numbers N1 and N2 by selecting one of the plurality of adsorption patterns 1 to 7 according to the surface size SZ (step S11). According to this configuration, since the numbers N1 and N2 suitable for the surface size SZ can be easily and quickly determined from the adsorption patterns 1 to 7, the amount of computational processing required to determine the numbers N1 and N2 can be reduced, and the cycle time of the operation can be shortened.

Furthermore, in the present embodiment, when the holding action performed according to the selected first adsorption mode n (for example, n=3, 6 or 7) fails (in step S13), the control device 20 selects a second adsorption mode n-1 whose total number Ns of the number N1 of the first adsorption ports 104 and the number N2 of the second adsorption ports 114 is less than the first adsorption mode n, and performs the holding action again according to the second adsorption mode n-1.

For example, as described above, the adsorption mode 3 is selected in the first step S11, and then the holding action is performed in step S12. At this time, there may be slight bumps on a portion of the surface Ws of the object W. In this case, when the surface Ws is adsorbed by one adsorption port 104 and one adsorption port 114, the adsorption port 104 or 114 may not be sealed due to the bumps, and the negative pressures ρ2 and ρ3 may not be formed. Alternatively, when the surface Ws is adsorbed by one adsorption port 104 and one adsorption port 114, the adsorption port 104 or 114 may slightly extend outward from the edge of the surface Ws, and the adsorption port 104 or 114 may not be sealed. In this case, the holding action of adsorption mode 3 may fail.

The inventors of the present invention have conducted active research and found that, when the gripping action of the suction mode 3 fails, the total number Ns=2 is reduced, and the gripping action is performed again in the suction mode 2, the possibility of the smooth part of the surface Ws being adsorbed by one suction port 104 in a manner avoiding the above-mentioned unevenness can be increased. In addition, the inventors of the present invention have also found that by reducing the total number Ns=2, if there is one suction port 104, the possibility of the edge of the surface Ws extending outward can be reduced. As a result, it was confirmed that even with one suction port 104, the object W can be gripped.

On the other hand, if the gripping action of the suction mode 3 is successful, it is possible to stably grip and lift an object W of larger size or mass. In addition, the same effect can be confirmed in the case where the suction mode 6 or 5 with a smaller total number Ns is selected in the second step S11 after the suction mode 7 or 6 is selected in the first step S11.

Thus, according to the present embodiment, first, the gripping action is tried with the suction mode n with a larger total number Ns. If successful, even an object W with a larger size or mass can be stably gripped and lifted. On the other hand, if a failure occurs, the gripping action can be retried with the suction mode n-1 with a smaller total number Ns, thereby increasing the probability of success of the gripping action. In this way, the operation efficiency can be improved, and the cycle time can be shortened.

Furthermore, in this embodiment, the first suction port 104 has an opening size R1 larger than that of the second suction port 114. In the first suction mode n (for example, n=2 or 5), the number N1 of the first suction ports 104 is set to 1 or more, and the number N2 of the second suction ports 114 is set to zero. Furthermore, in the second suction mode n-1, the number N2 of the second suction ports 114 is set to 1 or more, and the number N1 of the first suction ports 104 is set to zero.

Furthermore, when the holding action performed according to the selected first suction mode n fails, the control device 20 selects the second suction mode n-1 and performs the holding action again according to the second suction mode n-1. For example, as described above, the suction mode 5 is selected in the first step S11, and then the holding action is performed in step S12. In this case, the two suction ports 104 are used to suck the surface Ws, but at this time, the suction ports 104 may not be closed due to the above-mentioned unevenness or extension from the edge, and the holding action fails.

The inventors of the present invention have actively studied and found that when the holding action of the suction mode 5 fails, the suction mode 4 with the suction port 114 having a smaller opening size R can be used to avoid interference with the above-mentioned concave and convex parts or extension from the edge, so that the suction action is successful. In addition, the same effect can be confirmed when the suction mode 1 is selected in the second step S11 after the suction mode 2 is selected in the first step S11.

Thus, according to the present embodiment, first, the gripping action is tried with the suction mode n having a larger opening size R. If successful, even an object W with a larger size or mass can be stably gripped and lifted. On the other hand, if it fails, the gripping action can be retried with the suction mode n-1 having a smaller opening size R, thereby increasing the probability of success of the gripping action. In this way, the operation efficiency can be improved, and the cycle time can be shortened.

Furthermore, in the present embodiment, the plurality of first suction ports 104 and the plurality of second suction ports 114 are arranged in a manner arranged in the direction of the axes A2 and A3 of the robot 50. Furthermore, when the control device 20 performs the gripping action according to the second gripping mode n-1, the first suction ports 104 and the second suction ports 114 used for the gripping action are switched from the first gripping mode n to the second gripping mode n-1 (for example, from the above-mentioned gripping mode 5 to the gripping mode 4) by rotating the robot 50 around the axes A2 and A3. According to this configuration, the components of the robot 50 can be prevented from interfering with the surrounding environment (for example, the container H or the object W), and the gripping mode can be switched quickly and easily.

Furthermore, in the present embodiment, the robot 50 further has a suction port 84 that can inhale the outside air and suck and hold the object W, and the second suction port 114 has an opening size R2 that is smaller than the first suction port 104. Furthermore, when the surface size SZ obtained is smaller than the opening size R2 of the second suction port 114 (No in step S3), the control device 20 executes a holding action (step S21) of sucking and holding the object W by the suction port 84. According to this structure, even if the object W is so small that it cannot be sucked and held by the suction port 114, it can be stably sucked, held and lifted by the suction port 84. In this way, more types of objects W can be held.

In addition, in the above-mentioned embodiment, the case where the processor 40 selects to push the identification number "n" of the adsorption mode n selected in the previous step S11 forward by one adsorption mode n-1 when executing step S11 after step S16 in the process shown in FIG. 13 has been described. However, the processor 40 may also select to push the identification number "n" of the adsorption mode n selected in the previous step S11 backward by one adsorption mode n+1 when executing step S11 after step S16.

That is, the processor 40 selects adsorption mode n (n=1, 2, 3, ...) in step S11, and then executes steps S12 to S16 and then executes step S11 again. In this case, the processor 40 selects adsorption mode n+1. Assume that adsorption mode 2 (N1=1, N2=0) is selected in the first step S11, and then steps S12 to S16 are executed and then step S11 is executed for the second time. In this case, the processor 40 selects adsorption mode 3 (N1=1, N2=1) in the second step S11. The total number Ns of the number N1 and N2 of adsorption pattern 2 (first adsorption pattern) is 1, while the total number Ns of the number N1 and N2 of adsorption pattern 3 (second adsorption pattern) is 2.

That is, in this case, when the holding action performed according to the suction mode 2 selected in the first step S11 fails, the processor 40 selects suction mode 3 whose total number Ns of numbers N1 and N2 is greater than that of suction mode 2, and performs the holding action again in step S12 according to suction mode 3. In addition, after suction mode 5 or 6 is selected in the first step S11, the second step S11 is performed in the same manner, and the processor 40 selects suction mode 6 or 7 whose total number Ns increases by 1.

On the other hand, when the adsorption mode 4 is selected in the first step S11 and then the second step S11 is executed, the processor 40 selects the adsorption mode 5 in the second step S11. In this case, in the adsorption mode 4 (the first adsorption mode), the number N2 of the adsorption ports 114 is specified to be 2, and on the other hand, the number N1 of the adsorption ports 104 is specified to be 0.

Furthermore, in suction mode 5 (second suction mode), the number of suction ports 104 N1=2 is specified, and on the other hand, the number of suction ports 114 N2=0 is specified. That is, in this case, when the gripping action performed according to suction mode 4 selected in the first step S11 fails, the processor 40 selects suction mode 5 in which the opening size R of the suction port used for the gripping action becomes larger although the total number Ns is the same, and the gripping action is performed again in step S12 according to the suction mode 5. In addition, the same is true in the case where suction mode 1 or 3 is selected in the first step S11 and the second step S11 is executed, the processor 40 selects suction mode 2 or 4 in which the opening size R is larger although the total number Ns is the same.

As described above, when the processor 40 executes step S11 after step S16, it selects the suction mode n+1 and executes step S12 again according to the mode n+1. At this time, the processor 40 can switch the suction ports 104 and 114 used for the holding action from the suction mode n to the suction mode n+1 by rotating the robot 50 around the axis A1 (i.e., the axes A2 and A3).

In the above embodiment, the processor 40 determines whether to use the suction hand 54 by determining whether the surface size SZ is smaller than the opening size R2 of the suction port 114 in step S3 of FIG. 12. However, the present invention is not limited thereto. The processor 40 may also determine the type of the object W from the image data ID captured in step S1, and determine whether to use the suction hand 54 (i.e., the suction port 84) in the holding action based on the type.

Other examples of step S3 are described below. For example, the processor 40 uses a machine learning model LM1 (so-called AI (Artificial Intelligence) algorithm) to identify the type of object W from the image data ID. For example, the operator inputs the image data ID of various objects W and the data set DS1 of the label data LB representing the type of object W shown in the image data ID (resin fixed-shaped packaging box, paper fixed-shaped packaging box, irregular packaging bag, etc.) into the mechanical learning device LD (not shown). The mechanical learning device LD uses the data set DS1 to learn the mechanical learning model LM1 representing the correlation between the image data ID of the object W and the type of the object W. In addition, the processor 40 can also be configured in a manner to function as the mechanical learning device LD. The machine learning model LM1 is pre-stored in the memory 42.

Furthermore, in step S3, the processor 40 inputs the image data ID obtained in the most recent step S1 into the machine learning model LM1. The machine learning model LM1 outputs the label data LB that is correlated with the input image data ID as the optimal solution. The processor 40 specifies the type of item W from the label data LB output from the machine learning model LM1. For example, item W is set as a paper-shaped packaging box with a concave-convex surface. In this case, it is difficult for the suction hand 56 to hold item W by suction. In this case, in step S3, the processor 40 determines that the type of item W is a paper-shaped packaging box when it is identified from the label data LB output from the machine learning model LM1.

Furthermore, the processor 40 can suck and hold the concavo-convex article W by executing step S5 as shown in FIG18 . When holding the concavo-convex article W, a gap G is formed between the front end face 82 and the surface Ws, but a large flow of external air is continuously sucked into the suction port 84 through the gap. By the flow of such external air, the suction hand 54 can continuously suck and hold the concavo-convex article W at the suction port 84.

Instead, the object W is set as an irregular packaging bag. In this case, it is also difficult for the suction hand 56 to suck and hold the object W. In this case, the processor 40 determines that the type of the object W is an irregular packaging bag when it recognizes from the label data LB output by the machine learning model LM1 in step S3. In addition, the processor 40 can effectively suck and hold the irregular packaging bag by executing step S5 as shown in FIG. 19.

In addition, a data table DT2 may be pre-stored in the memory 42. The data table DT2 associates and stores various tag data LB with the suction hand 54 and suction patterns 1 to 7 used for the gripping action of the object W of the type represented by the tag data LB. In this case, the processor 40 can determine which of the suction hand 54 and suction patterns 1 to 7 should be used for the gripping action by applying the tag data LB output by the machine learning model LM1 to the data table DT2. In addition, the processor 40 is not limited to the machine learning model LM1, and can also specify the type of the object W based on input information from the operator.

In addition, in the above-mentioned embodiment, when the handler 40 holds the object W with the robot 50, the robot 50 may be rotated around the axis A1 to intentionally change the arrangement of the object W. For example, when the object W to be held is near the side wall of the container H, the holding action may become difficult because interference between the robot 50 and the side wall may occur.

Therefore, when the processor 40 determines that the object W near the side wall of the container H is to be grasped, the suction hand 56 or the attracting hand 54 abuts against the object W, and the robot 50 rotates around the axis A1. As a result, the components of the robot 50 can be prevented from interfering with the container H, and the object W is shifted from the vicinity of the side wall to the central area of the container H. In this way, the success rate of the grasping action of the object W can be increased.

In addition, the above-mentioned step S16 or S24 (avoidance action) may be omitted. In addition, in the above-mentioned embodiment, the case where the adsorption patterns 1 to 7 shown in FIG. 14 are determined has been described. However, the adsorption patterns 1 to 7 shown in FIG. 14 are just examples, and arbitrary numbers N1 and N2 may be determined as adsorption patterns n. In addition, the numbers N1 and N2 may be determined without determining the adsorption pattern n. For example, the processor 40 may determine the numbers N1 and N2 based on input information from the operator.

Alternatively, a machine learning model LM2 may be prepared in advance to represent the correlation between the image data ID (or the surface size SZ obtained from the image data ID) and the numbers N1 and N2 of the objects W. For example, an operator inputs a data set DS2 of the image data ID (or surface size SZ) of various objects W and the combination of the numbers N1 and N2 of the image data ID (surface size SZ) suitable for suction and gripping into the machine learning device LD.

The mechanical learning device LD uses the data set DS2 to learn the mechanical learning model LM2 that represents the correlation between the image data ID (surface size SZ) and the combination of the numbers N1 and N2. The mechanical learning model LM2 is pre-stored in the memory 42. In this case, the processor 40 inputs the image data ID captured in step S1 (or the surface size SZ obtained in step S2) into the mechanical learning model LM2 in the above-mentioned step S11. Then, the mechanical learning model LM2 outputs the combination of the numbers N1 and N2 that are correlated with the input image data ID (surface size SZ) as the optimal solution. In this way, the processor 40 can determine the numbers N1 and N2 based on the image data ID (surface size SZ).

In the above-mentioned embodiment, one of the force applying mechanisms 74 and 100 may be formed by a magnet generating a force applying force. Also, at least one of the force applying mechanisms 74 and 100 may be omitted from the robot 50, and at least one of the arms 70 and 98 may be formed by a rod-shaped member of a single body.

In addition, in the above-mentioned robot 50, the situation in which two suction ports 104 and two suction ports 114 are arranged alternately in the circumferential direction at an angle θ1=90° has been described. However, this is not limited to the above, and the angle θ1 may also be set to a divisor of 360°, such as 45°, 60° or 72°. Furthermore, the suction ports 104 and 114 are not limited to being arranged circumferentially around the suction port 84. For example, a plurality of suction ports 104 or 114 may also be arranged in a row at positions adjacent to the radially outer side of the suction port 84. Furthermore, the suction-type hand 56 may each have one suction port 104 and 114, but may also have any number of suction ports 104 and any number of suction ports 114. Furthermore, the robot 50 may also have a plurality of suction-type hands 54 (suction ports 84).

Furthermore, in the above-mentioned embodiment, the case where the suction hand 56 has the suction ports 104 and 114 with different opening sizes R1 and R2 has been described. However, this is not limited to the above, and the suction hand 56 may also have only the suction port 104 (or suction port 114) with the same opening size R1 (or R2). Alternatively, the suction hand 56 may further have a suction port with a larger opening size R1. Furthermore, the suction ports 104 and 114 may also have the same opening size R1 (or R2). In this case, the suction pads 96 and 110 may also be composed of welding pads of different types (external dimensions, shapes, materials or flexibility).

In the above embodiment, the suction hand 56 has been described as having a plurality of arms 98. However, the present invention is not limited thereto. For example, the suction hand 56 may also have a cylindrical ring arm coaxially fixed to the hand base 52 and having a one-piece shape. In this case, the plurality of suction pads 96 and 110 may also be arranged alternately from the axis of the ring arm to the lower end.

Furthermore, the suction pads 96 and 110 may be omitted from the robot 50, for example, the suction ports 104 and 114 may be directly formed on the shaft portion 108 or the lower end surface of the ring arm. Furthermore, the suction pad 76 may be omitted from the suction hand 54, for example, the suction port 84 may be directly formed on the shaft portion 70 (movable arm portion 80) lower end surface.

In the above embodiment, the axis A3 of the suction port 84, the axes A4 and A5 of the suction port 104, and the axes A6 and A7 of the suction port 114 are substantially parallel to each other. However, the present invention is not limited thereto, and at least one of the axes A4 to A7 (for example, all) may be inclined relative to the axis A3. In addition, the robot 12 is not limited to a vertical multi-joint type, and may be any type of robot such as a horizontal multi-joint type, a parallel linkage type, etc.

In addition, the visual sensor 14 may be omitted from the robot system 10. For example, identification information (e.g., a barcode) that specifies the type and surface size SZ of the object W may be marked on the object W, and the robot system 10 may further include a reading sensor RS that reads the identification information. Furthermore, the processor 40 may also obtain the surface size SZ of the object W based on the identification information read by the reading sensor RS.

The present disclosure has been described in detail above, but the present disclosure is not limited to the above-mentioned embodiments. These embodiments may be added, replaced, changed, partially deleted, etc., without departing from the scope of the present disclosure, or without departing from the scope of the present disclosure derived from the contents recorded in the scope of the patent application and its equivalents. Moreover, these embodiments may also be implemented in combination. For example, in the above-mentioned embodiments, the sequence of each action or the sequence of each processing is shown as an example, and is not limited to this. Moreover, the same applies to the use of numerical values or formulas in the description of the above-mentioned embodiments.

This disclosure describes the following aspects. (Aspect 1) A robot system 10, 200, 210, which is for holding an object W, comprises: a robot 12, which has a manipulator 50 including a first suction port 104 and a second suction port 114; and a control device 20, which causes the robot 12 to move the manipulator 50 to perform a holding action of holding the object W with the manipulator 50; the control device 20 obtains the surface size SZ of the object W to be held, and determines the number N1 of the first suction port 104 and the number N2 of the second suction port 114 used for the holding action according to the obtained surface size SZ. (Aspect 2) In the robot system 10, 200, 210 of aspect 1, a plurality of adsorption modes n are pre-set, each of which specifies the number N1 of the first adsorption ports 104 and the number N2 of the second adsorption ports 114. The control device 20 determines the numbers N1 and N2 by selecting one of the plurality of adsorption modes n according to the surface size SZ. (Aspect 3) In the robot system 10, 200, 210 of aspect 2, when the gripping action performed according to the selected first suction mode n fails, the total number Ns of the number N1 of the first suction ports 104 and the number N2 of the second suction ports 114 is selected to be less than the second suction mode n-1 of the first suction mode n, or the total number Ns is greater than the second suction mode n+1 of the first suction mode n, and the gripping action is performed again according to the second suction mode n-1 or n+1. (Aspect 4) A robot system 10, 200, 210 as in aspect 2 or 3, wherein the first suction port 104 has an opening size R1 larger than the second suction port 114, in the first suction mode n, the number N1 of the first suction ports 104 is set to be greater than 1, and on the other hand, the number N2 of the second suction ports 114 is set to be zero, in the second suction mode n-1, the number N2 of the second suction ports 114 is set to be greater than 1, and on the other hand, the number N1 of the first suction ports 104 is set to be zero, and when the holding action performed according to the selected first suction mode n fails, the control device 20 selects the second suction mode n-1, and performs the holding action again according to the second suction mode n-1. (Aspect 5) A robot system 10, 200, 210 as in any aspect 2 to 4, wherein the first suction port 104 has an opening size R1 larger than the second suction port 114, in the first suction mode n, the number N2 of the second suction ports 114 is set to be greater than 1, and on the other hand, the number N1 of the first suction ports 104 is set to be zero, and in the second suction mode n+1, the number N1 of the first suction ports 104 is set to be greater than 1, and on the other hand, the number N2 of the second suction ports 114 is set to be zero, and when the holding action performed according to the selected first suction mode n fails, the control device 20 selects the second suction mode n+1 and performs the holding action again according to the second suction mode n+1. (Aspect 6) A robot system 10, 200, 210 as in any aspect 3 to 5, wherein the plurality of first suction ports 104 and the plurality of second suction ports 114 are arranged in a manner arranged in the direction of the axes A2 and A3 of the manipulator 50, and when the control device 20 performs a gripping action according to the second gripping mode n-1, the first suction port 104 and the second suction port 114 used for the gripping action are switched from the first gripping mode n to the second gripping mode n-1 or n+1 by rotating the manipulator 50 around the axes A1, A2, A3. (Aspect 7) A robot system 10, 200, 210 as in any of aspects 1 to 6, wherein the robot arm 50 further has a suction port 84 for sucking in external air to suck the gripped object, and the second suction port 114 has an opening size R2 smaller than the first suction port 104. When the surface size SZ obtained by the control device 20 is smaller than the opening size R2 of the second suction port 114, the control device 20 performs a gripping action of sucking the gripped object W with the suction port 84. (Aspect 8) A robot system 10, 200, 210 for holding an object W comprises: a robot 12 having a manipulator 50 including a first suction port 104 and a second suction port 114; a visual sensor 14 for photographing the object W; a control device 20 for causing the robot 12 to move the manipulator 50 to perform a holding action of holding the object W with the manipulator 50; and a machine learning model LM2 for representing an image data ID of the object W. The control device 20 inputs the image data ID captured by the visual sensor 14 into the machine learning model LM2, and determines the number N1 of the first suction port 104 and the number N2 of the second suction port 114 used for the holding action of the object W shown in the image data ID. (Aspect 9) A method of holding an object W by a robot 50 including a first suction port 104 and a second suction port 114 having different opening sizes R, and obtaining a surface size SZ of the object W to be held, and determining the number N1 of the first suction port 104 and the number N2 of the second suction port 114 used for the holding action of the robot 50 to hold the object W according to the obtained surface size SZ.

10: Robot system 12: Robot 14: Vision sensor 16: First exhaust device 18A: Second exhaust device 18B: Second exhaust device 18C: Second exhaust device 18D: Second exhaust device 20: Control device 22: Robot base 24: Rotating body 26: Lower arm 28: Upper arm 30: Wrist 30a: Wrist base 30b: Wrist flange 32: Servo motor 34: Moving mechanism 40: Processor 42: Memory 44: I/O interface 46: Bus 50: Robot hand 52: Hand base 54: Suction hand 56: Suction hand 58: Mounting flange 60: Support platform 62: Column 63: Through hole 64: Mounting hole 66: Through hole 68: Through hole 70: Arm 72: Slider 72a: Through hole 74: Second force mechanism 76: Suction pad 78: Fixed arm 80: Movable arm 80a: Axial upper end 80b: Axial lower end 82: Front end 84: Suction port 86: Cylinder 86a: Cylinder body 86b: Cylinder shaft 88: Large suction hand 90: Large suction hand 92: Small suction hand 94: Small suction hand 96: Suction pad 98: Arm 100: First force-applying mechanism 102: Front end face 104: Adsorption port 106: Cylinder body 108: Shaft 110: Adsorption pad 112: Front end face 114: Adsorption port 120: Gas injection device 122: Airflow generating mechanism 122a: Gas inlet 122b: Spiral flow path 122c: Gas outlet 122d: Gas suction port 124: Flow path pipe 130: Gas injection device 132: Negative pressure generating mechanism 132a: Gas inlet 132b: Venturi flow path 132c: Gas outlet 132d: Gas suction port 132e: Nozzle 134: Flow path pipe 200: Robot system 202: Sensor 210: Robot system 212: Sensor A1~A7: Axis B: Arrow C1: Robot coordinate system C2: Tool coordinate system D1: Jet D1': Jet D2: Air flow DR1: Removal direction G: Gap G1: Jet G1': Jet G2: Air flow H: Container He: Open end IV: Arrow N1: Number N2: Number S1~S7: Step S11~S19: Step S21~S27: Step V: Arrow W: Object We: End Ws: Surface θ1: Angle

FIG. 1 is a schematic diagram of a robot system in an embodiment. FIG. 2 is a block diagram of the robot system shown in FIG. 1. FIG. 3 is a front view of a robot in an embodiment. FIG. 4 is a side view of the robot shown in FIG. 3 as viewed from arrow IV in FIG. 3. FIG. 5 is a bottom view of the robot shown in FIG. 3 as viewed from arrow V in FIG. 3. FIG. 6 is a three-dimensional view of the robot shown in FIG. 3 as viewed from above. FIG. 7 is a three-dimensional view of the robot shown in FIG. 3 as viewed from below. FIG. 8 shows the state in which the suction hand is retracted in the robot shown in FIG. 4. FIG. 9 is a schematic diagram of the first exhaust device shown in FIG. 2. FIG. 10 is a schematic diagram of the second exhaust device shown in FIG. 2. FIG. 11 shows the objects scattered and stacked in the container and the visual sensor photographing the objects. FIG. 12 is a flowchart showing an example of the action flow of the robot system shown in FIG. 1. FIG. 13 is a flowchart showing an example of the process of step S4 in FIG. 12. FIG. 14 shows an example of a data table of the suction mode. FIG. 15 shows the state of sucking and holding an object with a suction hand. FIG. 16 is a flowchart showing an example of the process of step S5 in FIG. 12. FIG. 17 shows the state of sucking and holding a small object with a suction hand. FIG. 18 shows the state of sucking and holding a concave-convex object with a suction hand. FIG. 19 shows the state of sucking and holding an amorphous object with a suction hand.

10: Robotic system

12:Robots

14: Visual sensor

20: Control device

22:Robot base

24: Rotating subject

26: Lower arm

28: Upper arm

30: Wrist

30a: Wrist base

30b: Wrist flange

34: Mobile mechanism department

50:Manipulator

52: Hand base

A1: Axis

C1: Robot coordinate system

C2: Tool coordinate system

Claims (9)

A robot system is used for holding an object and comprises: a robot having a manipulator including a first suction port and a second suction port; and a control device which causes the robot to move the manipulator to perform a holding action of holding the object with the manipulator; and the control device obtains the surface size of the object to be held, and determines the number of the first suction port and the number of the second suction port used for the holding action based on the obtained surface size. For example, in the robot system of claim 1, a plurality of adsorption modes are pre-set, each of which specifies the number of the first adsorption ports and the number of the second adsorption ports. The control device determines the number by selecting one of the plurality of adsorption modes according to the surface size. A robot system as claimed in claim 2, wherein the control device selects a second suction mode in which the total number of the first suction ports and the second suction ports is less than or greater than the first suction mode when the holding action performed according to the selected first suction mode fails, and performs the holding action again according to the second suction mode. A robot system as claimed in claim 2, wherein the first suction port has an opening size larger than that of the second suction port, In the first suction mode, the number of the first suction ports is set to be 1 or more, and on the other hand, the number of the second suction ports is set to be zero, In the second suction mode, the number of the second suction ports is set to be 1 or more, and on the other hand, the number of the first suction ports is set to be zero, When the holding action performed in accordance with the selected first suction mode fails, the control device selects the second suction mode, and performs the holding action again in accordance with the second suction mode. A robot system as claimed in claim 2, wherein the first suction port has an opening size larger than that of the second suction port, In the first suction mode, the number of the second suction ports is set to 1 or more, and on the other hand, the number of the first suction ports is set to zero, In the second suction mode, the number of the first suction ports is set to 1 or more, and on the other hand, the number of the second suction ports is set to zero, When the holding action performed in accordance with the selected first suction mode fails, the control device selects the second suction mode, and performs the holding action again in accordance with the second suction mode. A robot system as claimed in any one of claims 3 to 5, wherein the plurality of the first suction ports and the plurality of the second suction ports are arranged in a direction around the axis of the robot arm, and when the control device performs the holding action in accordance with the second suction mode, the first suction port and the second suction port used for the holding action are switched from the first suction mode to the second suction mode by rotating the robot arm around the axis. A robot system as claimed in claim 1, wherein the robot arm further has a suction port for sucking in external air to hold the object, the second suction port has an opening size smaller than the first suction port, and the control device performs the holding action of sucking and holding the object with the suction port when the surface size obtained is smaller than the opening size of the second suction port. A robot system that holds an object and comprises: a robot having a manipulator including a first suction port and a second suction port; a visual sensor that photographs the object; a control device that moves the robot to move the manipulator to perform a holding action of holding the object with the manipulator; and a mechanical learning model that represents the image data of the object and the correlation between the number of the first suction ports and the number of the second suction ports that should be used for the holding action of the object shown in the image data; and The control device inputs the image data captured by the visual sensor into the mechanical learning model, and determines the number of the first suction ports and the number of the second suction ports used for the holding action according to the number output by the mechanical learning model. A method for holding an object with a robot including a first suction port and a second suction port, wherein the method is to obtain the surface size of the object to be held, and to determine the number of the first suction ports and the number of the second suction ports used for the holding action of the robot to hold the object based on the obtained surface size.