JP7548063B2 - Robot hand control device and article pick-up system - Google Patents

Description

This disclosure relates to a robot hand control device and an item pick-up system.

Conventionally, an item picking system using an industrial robot is known, which picks up an item placed on an item placement section (e.g., a container), changes the position of the item using a specified holding means, and then places the item on a specified installation target (see, for example, Patent Document 1).

JP 2017-109271 A

However, many of the conventional article picking systems are based on the premise that the articles to be picked are aligned in a predetermined position on the article placement section, and the operation plan of the holding means when changing the position after picking the articles is determined in advance (see, for example, Patent Document 1). Therefore, the conventional article picking systems have the problem that they cannot operate properly in situations where, for example, a large number of articles are piled up in bulk on the article placement section.

The present disclosure has been made in consideration of the above problems, and aims to provide a robot hand control device and an item removal system that can remove items placed in various different positions on the item placement section from the item placement section, change the position to a target position, and hold the items.

The present disclosure mainly solves the above-mentioned problems.
A control device for a robot hand having a holding means for rotatably holding an object, comprising:
a posture detection unit for detecting a current posture of the article;
a rotation axis setting unit that sets, for the article, an article-side rotation axis to be used when changing the article from the current orientation to the target orientation based on the current orientation of the article and the target orientation of the article at the time of placing, and a target rotation amount based on the article-side rotation axis;
an operation plan determination unit that determines an operation plan for the holding means for changing the article from the current position to the target position based on article information related to the article side rotation axis and the target rotation amount, and holding means information related to the holding means side rotation axis by which the holding means can rotate the article;
The control device is provided with:

In other respects,
An article pick-up system having the above control device.

The robot hand control device according to the present disclosure can remove objects placed in various different positions from the object placement section, change their position to a target position, and then hold them.

FIG. 1 is a diagram showing an overall configuration of an article pick-up system according to a first embodiment; FIG. 1 is a diagram showing a configuration of an article to be picked up by the article pick-up system according to the first embodiment; FIG. 1 is a diagram showing a configuration of a control system of an article pickup system according to a first embodiment; FIG. 1 is a diagram showing a detailed configuration of a robot hand according to a first embodiment; FIG. 13 is a diagram showing an example of an operation for changing the posture of an article by a suction head of the robot hand according to the first embodiment; FIG. 13 is a diagram showing an example of an operation for changing the posture of an article by a suction head of the robot hand according to the first embodiment; FIG. 13 is a diagram showing an example of an operation for changing the posture of an object by a gripping member of a robot hand; FIG. 1 is a diagram showing an example of an operation of picking up an item by a suction head of a robot hand according to a first embodiment; FIG. 1 is a diagram showing an example of an operation of picking up an item by a gripping member of a robot hand according to a first embodiment; FIG. 1 is a diagram for explaining an operation of transferring an article between a suction head and a gripping member of a robot hand according to a first embodiment; FIG. 1 is a diagram for explaining an operation of transferring an article between a suction head and a gripping member of a robot hand according to a first embodiment; FIG. 1 is a diagram for explaining an operation of transferring an article between a suction head and a gripping member of a robot hand according to a first embodiment; FIG. 10 is a diagram for explaining the processing of a rotation axis setting unit according to the first embodiment; 1 is a flowchart showing a series of processes performed when a control unit according to a first embodiment determines an operation plan for a holding means. FIG. 13 is a diagram showing a configuration of a robot hand according to a second embodiment; FIG. 13 is a diagram showing a configuration of a robot hand according to a third embodiment; FIG. 13 is a diagram showing a configuration of a robot hand according to a third embodiment;

A preferred embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that in this specification and drawings, components having substantially the same functions are designated by the same reference numerals to avoid redundant description.

In addition, unless otherwise specified, in each drawing, the upward direction in the drawing represents the vertical upward direction, the downward direction in the drawing represents the vertical downward direction, and the horizontal direction in the drawing represents the horizontal direction. In the following explanations, the upward direction in the drawing will be referred to as the "upward direction", the downward direction in the drawing will be referred to as the "downward direction", and the horizontal direction in the drawing will be referred to as the "horizontal direction".

First Embodiment
<Overall configuration of the article pick-up system>
Hereinafter, the configuration of an article pick-up system according to an embodiment of the present invention will be described with reference to FIGS.

Figure 1 is a diagram showing the overall configuration of an item pick-up system 1 according to this embodiment. Figure 2 is a diagram showing the configuration of an item 10 to be picked up by the item pick-up system 1 according to this embodiment. Figure 3 is a diagram showing the configuration of a control system for the item pick-up system 1 according to this embodiment.

The item removal system 1 according to this embodiment is a system for removing individual items 10 from a group of items 10W piled up in a bulk item loading section 2 (e.g., a container), holding and transporting the removed items 10, and installing them in an aligned state on an installation target 20.

In the article removal system 1 according to this embodiment, the bolt member is the article 10 (hereinafter simply referred to as "article 10") to be removed from the article placement section 2. The article 10 (bolt member) has a long and slender leg 10a and a head 10b formed at one end of the leg 10a and wider than the leg 10a. The installation target 20 has, for example, a number of holes 21 through which the legs 10a of the article 10 can be inserted. After removing the article 10 from the article placement section 2, the article removal system 1 changes the position of the article 10 to a position corresponding to the hole shape of the hole 21 of the installation target 20, and then installs the article 10 in the hole 21 of the installation target 20.

In other words, the item removal system 1 is capable of removing items 10 in various positions that are placed on the item placement section 2, and holding the items in a changed target position that corresponds to the hole shape of the hole 21 of the installation target 20.

In this embodiment, the target posture of the article 10 is one in which the head 10b faces upward and the legs 10a face downward, corresponding to the shape of the hole 21 of the installation target 20 (hereinafter, simply referred to as the "target posture of the article 10"). In this embodiment, in expressing the degree of inclination of the current posture of the article 10 in the three-dimensional coordinate system, the posture in which the head 10b faces upward and the legs 10a face downward, which corresponds to this target posture, is also referred to as the "reference posture of the article 10".

In the item removal system 1 according to this embodiment, the center of gravity of the bolt member (item 10) is set as the center of coordinates, the long axis direction of the bolt member (item 10) (up and down of item 10) is set as the z-axis, and the two directions of the short axis of the bolt member (item 10) perpendicular to the z-axis (front and back and left and right of item 10) are set as the x-axis and y-axis, respectively, and the attitude of the bolt member (item 10) is expressed by three axes: roll angle (rotation angle about the x-axis), pitch angle (rotation angle about the y-axis), and yaw angle (rotation angle about the z-axis) (see FIG. 2).

In addition, due to the shape characteristics of the bolt member (item 10), the x-axis, y-axis, and z-axis correspond to rotation axes (hereinafter also referred to as "rotatable axes") that can stably rotate item 10.

The item pick-up system 1 includes a robot arm 30, a robot hand 40, an imaging unit 50, and a control unit 60.

<Robot arm>
The robot arm 30 is, for example, a vertical articulated robot, and three-dimensionally changes the position of the robot hand 40. The robot arm 30 includes a base 31 placed on a floor surface or the like, a plurality of links 32 connected in series to the base 31, a plurality of joints 33 provided at the connection portions, and a plurality of joint motors 34 (see FIG. 2 ) that drive the joints 33.

The robot arm 30 is configured to translate the robot hand 40 from a reference position in the up-down, left-right, and front-rear directions (see the arrows in FIG. 1). The operation of the robot arm 30 is controlled under the control of the control unit 60.

<Robot Hand>
The robot hand 40 is provided at the tip of the robot arm 30, and uses holding means 41, 42 to pick up articles 10 one by one from the group of articles 10W placed on the article placement unit 2 and hold the articles 10. The robot hand 40 then changes the posture of the article 10 to a target posture using the holding means 41, 42, transports the article 10 to the installation target 20, and places the article 10 in the hole 21 of the installation target 20. The operation of the robot hand 40 is controlled under the control of the control unit 60. The robot hand 40 according to this embodiment has a suction head 41 and a gripping member 42 as the holding means 41, 42 (described later with reference to FIG. 4).

<Imaging unit>
The imaging unit 50 is, for example, a camera device that captures an image of the group of articles 10W placed on the article placement unit 2 and outputs image data obtained by the image capture to the control unit 60. Note that the imaging unit 50 performs imaging multiple times while shifting the imaging position so that the position and orientation of the articles 10 placed on the article placement unit 2 in three-dimensional space can be detected from the image data. The imaging unit 50 may also be configured with an imaging device capable of acquiring distance data from the imaging unit 50 to the articles 10, such as a stereo camera or a radar device.

The imaging unit 50 is preferably arranged so as to be able to image the item 10 held by the robot hand 40. This makes it possible to determine an operation plan for the holding means 41, 42 of the robot hand 40, taking into consideration changes in the posture of the item 10 when the robot hand 40 picks the item 10 from the item placement unit 2 (details will be described later).

<Control Unit>
The control unit 60 communicates with each part of the item pickup system 1 (the robot arm 30, the robot hand 40, and the imaging unit 50) to centrally control them.

The control unit 60 (corresponding to the "control device" of the present invention) is, for example, a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input port, and an output port. The functions of the control unit 60 (the attitude detection unit 61, the rotation axis setting unit 62, and the operation plan determination unit 63, which will be described later) are realized, for example, by the CPU referring to the control programs and various data stored in the ROM and RAM.

The control unit 60, for example, acquires image data from the imaging unit 50, and detects the position and orientation in three-dimensional space of one or more items 10 from the group of items 10W placed on the item placement unit 2 based on the image data. The control unit 60 then determines, for example, the item 10 located at the top of the group of items 10W placed on the item placement unit 2 as the item to be removed, and controls the robot arm 30 and the robot hand 40 based on the position and orientation of the item 10. That is, through such control, the control unit 60 causes the robot hand 40 to hold the item 10 and place the held item 10 in the hole 21 of the placement target 20.

<Detailed configuration of the robot hand>
Next, the detailed configuration of the robot hand 40 according to this embodiment will be described with reference to FIGS. 4 to 8C.

Figure 4 is a diagram showing the detailed configuration of the robot hand 40 according to this embodiment. In addition, in Figure 4, the P axis represents the rotation axis of the gripping member 42 that holds the item 10 rotatably around an axis in the lateral direction (here, the horizontal direction), and the Q axis represents the rotation axis of the suction head 41 that holds the item 10 rotatably around an axis in the up-down direction (here, the vertical direction).

As shown in FIG. 4, the robot hand 40 has a plurality of holding means 41, 42 that each rotatably hold the article 10. Specifically, the robot hand 40 according to this embodiment has suction heads 41 and gripping members 42 that each hold the article 10 and rotatably hold the article 10 in different directions.

The suction head 41 generates a suction force at the tip of the head by vacuuming or magnetic force, thereby suctioning the item 10 located opposite the suction head 41 and holding the item 10. The suction head 41 is, for example, configured in a nozzle shape and extends downward from the center position of the hand base 40m attached to the tip of the robot arm 30.

The suction head 41 can be rotated around an axis in the direction of suctioning the article 10 (typically around an axis in the vertical direction) with respect to the hand base 40m by a suction head rotation mechanism (not shown) built into the hand base 40m. Specifically, the suction head 41 has a rotation axis (see the Q axis in FIG. 4; hereinafter, also referred to as the "Q axis" or the "holding means side rotation axis Q axis") along the extension direction of the nozzle, with the tip of the nozzle as the center of rotation. In addition, the suction head 41 can be raised and lowered with respect to the hand base 40m by a nozzle lifting mechanism built into the hand base 40m. The suction head 41 is disposed between the left arm 42A and the right arm 42B that constitute the gripping member 42, and is raised and lowered between them.

The gripping member 42 is composed of a pair of arms 42A, 42B extending downward from the hand base 40m, and holds the article 10 by clamping both sides of the article 10 between the left arm 42A and the right arm 42B. The gripping member 42 is connected to a gripping member drive mechanism that adjusts the lateral distance between the left arm 42A and the right arm 42B (hereinafter referred to as the "inter-member distance"), and performs opening and closing operations in the lateral direction (P direction in FIG. 4) under the control of the control unit 60. That is, the gripping member 42 clamps the article 10 from both sides and holds the article 10 by controlling the operation so that the distance between the pair of arms 42A, 42B is narrowed. Also, the gripping member 42 releases the holding state of the article 10 by controlling the operation so that the distance between the pair of arms 42A, 42B is widened. The gripping member drive mechanism that operates the gripping member 42 is composed of, for example, link mechanisms 42As and 42Bs connected to the pair of arms 42A and 42B, respectively, and a link mechanism drive source (for example, a motor or cylinder, not shown) built into the hand base 40m.

The pair of arms 42A, 42B are provided at their respective tips with contact parts 42Aa, 42Ba that come into contact with the article 10 when the gripping member 42 holds the article 10. The contact parts 42Aa, 42Ba are rotatably supported by the arms 42A, 42B so that the opening and closing direction of the gripping member 42 (i.e., the direction in which the article 10 is clamped from both sides) (see the P axis in FIG. 4. Hereinafter, also referred to as the "P axis" or the "holding means side rotation axis P axis") serves as the rotation axis. The contact parts 42Aa, 42Ba are configured to rotate the article 10 gripped by the gripping member 42 around the P axis. The holding means side rotation axis P axis is set to extend, for example, in the horizontal direction. The contact parts 42Aa, 42Ba are driven, for example, by motors 42At, 42Bt provided on the pair of arms 42A, 42B, respectively.

The contact portions 42Aa and 42Ba have a concave shape (e.g., a semi-cylindrical concave shape) that fits with the side of the leg portion 10a of the article 10 to ensure the stability of the held state of the article 10. When the gripping member 42 holds the article 10, the gripping member 42 clamps the article 10 so that the side of the leg portion 10a of the article 10 fits into the concave shape of the contact portions 42Aa and 42Ba (see FIG. 6). However, from the viewpoint of the stability of the held state of the article 10, it is preferable that the gripping position of the article 10 in the gripping member 42 is a position where the rotation axis of the gripping member 42 (here, the P axis) and the rotatable axis of the article 10 (here, the x-axis or y-axis) are aligned.

Now, with reference to Figures 5A to 8C, we will explain the operation of changing the posture of the article 10 using the suction head 41 and gripping member 42 of the robot hand 40.

Figures 5A and 5B are diagrams showing an example of the posture change operation of the article 10 by the suction head 41 of the robot hand 40 according to this embodiment. Figure 6 is a diagram showing an example of the posture change operation of the article 10 by the gripping member 42 of the robot hand 40 according to this embodiment.

Figure 7A is a diagram showing an example of the pickup operation of an item 10 by the suction head 41 of the robot hand 40 according to this embodiment. Figure 7B is a diagram showing an example of the pickup operation of an item 10 by the gripping member 42 of the robot hand 40 according to this embodiment.

Figures 8A, 8B, and 8C are diagrams illustrating the transfer operation of the article 10 between the suction head 41 and the gripping member 42 of the robot hand 40 according to this embodiment.

When the robot hand 40 uses the suction head 41 to change the posture of the item 10, the robot hand 40 rotates the suction head 41 around the Q axis relative to the hand base 40m while holding the item 10 at the tip of the suction head 41 (see Figures 5A and 5B).

The suction head 41 holds the item 10 by suctioning it with the suction force generated at the tip of the head. Therefore, when changing the position of the item 10 using the suction head 41, it is preferable that the holding state of the item 10 is such that the head tip of the suction head 41 faces the flat surface of the item 10 (here, the upper end surface of the head 10b or the lower end surface of the leg 10a of the item 10) as shown in FIG. 5A, and the rotation axis (Q axis) of the suction head 41 coincides with the rotatable axis of the item 10 (here, the z axis). In this case, it is possible to stably change the position of the item 10 without the risk of dropping the item 10 midway.

However, by adjusting the suction force (i.e., by increasing the suction force), the suction head 41 can hold the item 10 relatively without being restricted by the position of the item 10. For example, as shown in FIG. 5B, the suction head 41 can hold the item 10 even when the head tip of the suction head 41 faces the side of the item 10, and can rotate the item 10 around the Q axis in this held state.

The suction head 41 is configured to be able to pick up the articles 10 one by one from the group of articles 10W placed on the article placement section 2 (see FIG. 7A). When the suction head 41 is to pick up an article 10 from the article placement section 2, the control section 60 lowers the suction head 41 from the hand base section 40m and brings the head tip of the suction head 41 close to the article 10 to be picked up. Then, with the head tip of the suction head 41 facing the article 10 to be picked up, the control section 60 generates a suction force of the suction head 41, causing the suction head 41 to pick up the article 10.

When the suction head 41 is used to remove the item 10 from the item placement section 2, as described above, from the viewpoint of the stability of the state in which the item 10 is held, the control section 60 causes the suction head 41 to approach the item 10 so that, as far as possible, the head tip of the suction head 41 faces the flat surface of the item 10 (here, the upper end surface of the head 10b or the lower end surface of the leg 10a of the item 10) and the rotation axis (Q axis) of the suction head 41 coincides with the rotation axis (z axis) of the item 10.

On the other hand, when the robot hand 40 uses the gripping member 42 to change the posture of the article 10, the gripping member 42 rotates the contact portions 42Aa and 42Ba of the gripping member 42 around the P axis (here, a horizontal axis) while clamping the article 10 so as to align the rotation axis of the gripping member 42 (here, the P axis) with the rotatable axis of the article 10 (here, the x axis or y axis) (see Figure 6).

Similarly to the suction head 41, the gripping member 42 is configured to be able to pick up the articles 10 one by one from the group of articles 10W placed on the article placement section 2 (see FIG. 7B). When the gripping member 42 is used to pick up an article 10 from the article placement section 2, the control section 60 opens the left arm 42A and the right arm 42B and makes the left arm 42A and the right arm 42B approach the article 10 to be picked up. Then, the control section 60 moves the left arm 42A and the right arm 42B so that the left arm 42A and the right arm 42B are on both the left and right sides of the article 10 to be picked up (i.e., operates the robot arm 30). In this state, the control section 60 closes the gripping member 42 to make the gripping member 42 grip the article 10. When the gripping member 42 is used to remove the article 10 from the article placement section 2, as described above, from the viewpoint of the stability of the state in which the article 10 is held, the control section 60 causes the gripping member 42 to approach the article 10 so that the rotation axis of the gripping member 42 (here, the P axis) and the rotatable axis of the article 10 (here, the x-axis or y-axis) are aligned.

When removing an item 10 from the item placement section 2 (container), the control section 60 may drop one item 10 from the group of bulk items 10W onto the flat surface of the item placement section 2 and pick up the dropped item 10.

In the robot hand 40 according to this embodiment, the suction head 41 and the gripping member 42 can exchange the object 10 with each other (see FIGS. 8A to 8C). Specifically, the suction head 41 is disposed between the left arm 42A and the right arm 42B that constitute the gripping member 42, and moves up and down between them. When the gripping member 42 holds the object 10, the holding position of the object 10 is within the movable range of the suction head 41. The P axis, which is the rotation axis of the suction head 41, and the Q axis, which is the rotation axis of the gripping member 42, are set to intersect with each other, for example, at the center position between the left arm 42A and the right arm 42B. This allows the suction head 41 and the gripping member 42 to exchange the object 10 with each other.

However, when transferring the article 10 between the suction head 41 and the gripping member 42, the operation of each of the suction head 41 and the gripping member 42 is controlled taking into account the difference in the holding method of each of the suction head 41 and the gripping member 42.

For example, when the robot hand 40 according to the present embodiment transfers the article 10 from the suction head 41 to the gripping member 42, the suction head 41 and the gripping member 42 are moved to appropriate positions so that the rotation axis (here, the P axis) of the gripping member 42 and the rotatable axis (here, the x-axis or y-axis) of the article 10 are aligned, and then the robot hand 40 transfers the article 10 (see FIG. 6). For this reason, the control unit 60 changes the lifting and lowering position stop of the suction head 41 as shown in FIG. 8A and FIG. 8B depending on whether the article 10 held by the suction head 41 is facing upward or downward (see FIG. 8A and FIG. 8B). In addition, when the article 10 held by the suction head 41 is facing horizontally, the control unit 60 rotates the orientation of the contact portions 42Aa and 42Ba of the gripping member 42 so that the concave shapes of the contact portions 42Aa and 42Ba are aligned with the orientation of the article 10 (see FIG. 8C).

On the other hand, when the robot hand 40 according to this embodiment transfers the item 10 from the gripping member 42 to the suction head 41, it moves the suction head 41 and the gripping member 42 to appropriate positions so that the rotation axis of the suction head 41 (here, the Q axis) and the rotation axis of the item 10 (here, the z axis) are aligned, and then performs the transfer operation of the item 10 (not shown).

[Robot hand control method]
4 to 10, a method for controlling the robot hand 40 will be described. The operation of the robot hand 40 is performed by the control unit 60 as described above.

The control unit 60 has a posture detection unit 61, a rotation axis setting unit 62, and an operation plan determination unit 63, and by implementing these functions, determines an operation plan for the holding means of the robot hand 40 (in this embodiment, the suction head 41 and the gripping member 42), and operates the robot hand 40 based on the operation plan.

Figure 9 is a diagram explaining the processing of the rotation axis setting unit 62 according to this embodiment.

Figure 10 is a flowchart showing a series of processes performed by the control unit 60 in this embodiment when determining an operation plan for the holding means 41 and 42.

The attitude detection unit 61 detects the current attitude of the item 10, for example, based on image data acquired from the imaging unit 50. At this time, the attitude detection unit 61 identifies, for example, from among the group of items 10W placed on the item placement unit 2, an item 10 that is in a position that can be held by the holding means 41, 42 (for example, the item 10 at the top), as the item 10 to be removed, and detects the attitude of the item 10 to be removed. Then, the attitude detection unit 61 passes information related to the detected current attitude of the item 10 to the rotation axis setting unit 62 (and the operation plan determination unit 63).

However, the posture of the article 10 may change when it is picked up from the article placement section 2 by the holding means 41, 42 (especially when the suction head 41 is used). Furthermore, when the articles 10 are placed in a bulk state, the posture of the article 10 may not be accurately detected due to the presence of surrounding objects. From this perspective, the posture detection unit 61 may detect the current posture of the article 10 when it is picked up from the article placement section 2 by the holding means 41, 42, and the rotation axis setting unit 62 and the operation plan determination unit 63 may execute a process of determining the operation plan of the holding means 41, 42 based on the current posture of the article 10 when it is picked up from the article placement section 2 by the holding means 41, 42.

In addition, if the posture of the item 10 while it is placed on the item placement section 2 cannot be accurately detected, the control section 60 may pick up the item 10 with the suction head 41 based on, for example, only the position information of a portion of the item 10 (for example, the position of the top surface of the item 10).

The rotation axis setting unit 62 sets a rotation axis (hereinafter referred to as the "used rotation axis" or "item-side rotation axis") to be used for changing the item 10 from the current attitude to the target attitude based on the current attitude of the item 10 detected by the attitude detection unit 61 and the target attitude of the item 10 at the time of placement. In addition, the rotation axis setting unit 62 sets a target rotation amount for rotating the item 10 to change the item 10 from the current attitude to the target attitude based on this used rotation axis.

In general, the position and direction of the rotation axis (i.e., the rotatable axis) around which the item 10 can be stably rotated is determined based on the shape of the item 10 and the center of gravity of the item 10. For example, for a bolt, which is the item 10 to be removed in this embodiment, the long axis direction (z axis) of the item 10 at the center of gravity of the item 10 and the short axis direction (x axis, y axis) of the item 10 at the center of gravity of the item 10 are the rotatable axes (see FIG. 2). The rotatable axis of the item 10 is set in advance by the user for each type of item 10, for example. Therefore, the rotation axis setting unit 62 according to this embodiment is configured to select a rotation axis to be used for changing the position of the item 10 from among the rotatable axes preset for the item 10 based on the current position of the item 10 and the target position of the item 10 at the time of placement, and to set the target rotation amount with the rotation axis to be used as the center of rotation.

Here, the "target posture of the article 10 at the time of placement" is, as described above, for example, the posture when the robot hand 40 places the article 10 on the installation target 20. As described above, the target posture in this embodiment is a posture in which the long axis of the article 10 is oriented along the vertical direction and the head 10b of the article 10 faces vertically upward (i.e., a posture in which the positive direction of the z-axis set on the article 10 faces vertically upward).

When the articles 10 are placed on the article placement section 2, they take on various different postures depending on the article 10 to be picked up. Therefore, when picking the articles 10 from the article placement section 2 and then changing the posture to the target posture, it is necessary to rotate the articles 10 to be picked up by different amounts of rotation in different directions using the holding means 41, 42.

The rotation axis setting unit 62 calculates the difference between the current attitude and the target attitude for the three rotation axes x, y and z of the article 10 (i.e., the difference between the roll angle, pitch angle, and yaw angle) to set the rotation axis to be used and the required target rotation amount around the rotation axis to be used. For example, in the state shown in FIG. 9, in the current attitude of the article 10, the positive direction of the z axis of the article 10 is tilted from the vertical direction around the y axis, so the rotation axis setting unit 62 sets the y axis as the rotation axis to be used and sets the tilt angle of the positive direction of the z axis of the article 10 around the y axis as the target rotation amount.

The motion plan determination unit 63 determines a motion plan for the holding means 41, 42 for changing the article 10 from the current posture to the target posture based on information about the rotation axis in use set in the rotation axis setting unit 62 and the target rotation amount based on the rotation axis in use, and information about the holding means 41, 42 (here, information about the suction head 41 and the gripping member 42) about the holding means side rotation axes (here, the P axis and the Q axis) on which the holding means 41, 42 of the robot hand 40 can rotate the article 10.

The holding means information referred to by the operation plan determination unit 63 is stored in advance in a storage unit (e.g., ROM) of the control unit 60. Such holding means information may include various information such as the rotation direction of each of the rotation axes (here, the P axis and the Q axis) of the multiple holding means 41, 42, the holding method of the item 10 of each of the multiple holding means 41, 42, mechanism information required for each of the multiple holding means 41, 42 to perform a desired operation, the contact state with the item 10 when each of the multiple holding means 41, 42 holds the item 10 (e.g., contact area and contact angle), and the movable range when each of the multiple holding means 41, 42 approaches the item 10. In addition, the storage unit of the control unit 60 may include information on the size and shape of the item 10 as information on the item 10.

The operation plan of the holding means 41, 42 determined by the operation plan determination unit 63 includes, for example, (1) information identifying the posture-changing holding means (hereinafter abbreviated as "posture-changing holding means") to be used to change the article 10 from the current posture to the target posture among the multiple holding means 41, 42 (here, the suction head 41 and the gripping member 42) possessed by the robot hand 40, (2) information identifying the picking holding means (hereinafter abbreviated as "picking holding means") to be used to pick the article 10 placed on the article placement unit 2 among the multiple holding means 41, 42 (here, the suction head 41 and the gripping member 42) possessed by the robot hand 40, and (3) information related to the operation of the picking holding means and/or posture-changing holding means when transferring the article 10 from the picking holding means to the posture-changing holding means.

The operation plan determination unit 63 determines these operation plans each time, taking into consideration that the postures of the items 10 placed on the item placement unit 2 vary widely, for example, according to the current posture of the item 10 to be removed (the current posture of the item 10 when placed on the item placement unit 2, or the current posture of the item 10 when picked up from the item placement unit 2).

Here, the operation plan determination unit 63 determines the posture changing holding means from among the multiple holding means 41, 42 as the operation plan for each operation because the posture of the article 10 placed on the article placement unit 2 varies, and the directions in which the article 10 can be rotated by each of the multiple holding means 41, 42 are different. In the robot hand 40 according to this embodiment, the suction head 41 is a mechanism for rotating the article 10 around a vertical axis (around the Q axis), while the gripping member 42 is a mechanism for rotating the article 10 around a horizontal axis (around the P axis) (see Figures 5A, 5B, and 6). Therefore, the operation plan determination unit 63 determines the posture changing holding means from among the multiple holding means 41, 42 in accordance with the rotation axis to be used set in the rotation axis setting unit 62.

For example, as shown in FIG. 9, when the rotation axis to be used set in the rotation axis setting unit 62 is the y-axis, in order to change the article 10 from the current posture to the target posture, it is necessary to rotate the article 10 around a horizontal axis. Therefore, in the embodiment shown in FIG. 9, the operation plan determination unit 63 determines the gripping member 42 as the posture change holding means, and determines the amount of rotation using the gripping member 42 to be the target amount of rotation set in the rotation axis setting unit 62.

Here, the operation plan determination unit 63 determines the picking holding means from among the multiple holding means 41, 42 as an operation plan for each operation because the failure rate during picking varies for each of the multiple holding means 41, 42 depending on the placement state of the article 10, etc. For example, the gripping member 42 holds the article 10 by clamping it from both sides (see FIG. 7B), and can hold the article 10 in a stable state, but there are restrictions on the target article 10 that can be picked from the article placement unit 2 due to the relationship between the area in which the gripping member 42 can move, the posture that the gripping member 42 can take, and the area occupied by the gripping member 42 itself. In this regard, the suction head 41 can pick the article 10 from the article placement unit 2 by suctioning one side of the article 10 with the head tip (see FIG. 7A), so it can pick the article 10 from the article placement unit 2 relatively freely regardless of the posture of the article 10. However, depending on the position of the item 10 being held, the suction head 41 may lack stability in its holding state.

From this viewpoint, the operation plan determination unit 63 determines the picking holding means from among the multiple holding means 41, 42 based on, for example, the placement state of the item 10 placed on the item placement unit 2 (e.g., the posture of the item 10 and the presence of objects surrounding the item 10), the holding method of the multiple holding means 41, 42 for the item 10, the contact state with the item 10 when each of the multiple holding means 41, 42 holds the item 10 (e.g., the contact area and contact angle), and the movable range when each of the multiple holding means 41, 42 approaches the item 10. However, the operation plan determination unit 63 does not necessarily need to determine the picking holding means by considering all of the above elements, and may determine the picking holding means by considering only at least one of the above elements. Then, the operation plan determination unit 63 determines the approach method of the determined picking holding means to the item 10 (e.g., the position of the robot hand 40) based on the determined picking holding means and the position and posture of the item 10 placed on the item placement unit 2.

For example, as shown in FIG. 9, when the current posture of the article 10 is significantly tilted from the reference posture of the article 10, picking with the gripping member 42 is difficult in terms of the contact manner with the gripping member 42 (contact portions 42Aa, 42Ba). Therefore, in the embodiment shown in FIG. 9, the motion plan determination unit 63 determines the suction head 41 as the picking holding means. The motion plan determination unit 63 then determines a motion plan to move the robot hand 40 so that the nozzle tip of the suction head 41 faces the center of gravity of the side of the article 10, for example.

The operation plan determination unit 63 determines the operation of the picking holding means and/or the posture change holding means when transferring the item from the picking holding means to the posture change holding means as the operation plan for each operation, because, as described above, the posture change holding means, the picking holding means, and the posture of the item 10 when picked are different each time.

In addition, when transferring an item 10 from the picking holding means to the position changing holding means, information regarding the operation of the picking holding means and/or the position changing holding means includes, for example, information regarding the rotation stop position and/or the lift stop position of the picking holding means and/or the position changing holding means (see Figures 8A to 8C).

For example, in the embodiment of FIG. 9, as described above, the suction head 41 is determined as the picking holding means, and the gripping member 42 is determined as the posture changing holding means. At this time, the operation plan determination unit 63 determines the operation for transferring the article 10 from the suction head 41 to the gripping member 42. For example, as shown in FIG. 8C, the operation plan determination unit 63 determines an operation plan in which the suction head 41 rotates the article 10 a predetermined amount, and then the contact portions 42Aa and 42Ba of the gripping member 42 are rotated a predetermined amount, and the suction head 41 is lowered a predetermined amount so that the holding position of the article 10 is located between the contact portions 42Aa and 42Ba of the gripping member 42.

The targets, etc., that the operation plan determination unit 63 determines as an operation plan for each operation can be changed in various ways.

The operation plan determination unit 63 may, for example, determine, as an operation plan for each operation, which of the multiple holding means 41, 42 is to be used to pick up the item 10 placed on the item placement unit 2 and then place it on the installation target 20. However, in the item pick-up system 1 according to this embodiment, the operation of pushing the item 10 from above to below is an operation that only the suction head 41 can perform, and therefore, the suction head 41 is uniquely determined as the installation holding means.

The operation plan determination unit 63 may also select the suction head 41 as the picking holding means for each operation plan, for example. This is because the suction head 41 can pick up the item 10 relatively stably, regardless of the position of the item 10.

Now, with reference to Figure 10, we will explain the series of processes that the control unit 60 performs when determining the operation plan for the holding means 41 and 42.

In step S1, the control unit 60 first performs initial settings. In this step S1, the control unit 60 sets the target posture of the item 10 at the time of placement, and information on the holding means 41, 42 of the robot hand 40, for example, based on the contents of the user's input.

Here, the target posture of the article 10 at the time of placement corresponds to, for example, the shape of the hole 21 (i.e., the portion where the article 10 is placed) of the installation target 20, and is set to a posture in which the positive direction of the z-axis set on the article 10 faces vertically upward. In addition, the information on the holding means 41, 42 possessed by the robot hand 40 includes, for example, the holding method of the holding means 41, 42 possessed by the robot hand 40, and information on the holding means side rotation axes (e.g., the P axis and the Q axis) on which the holding means 41, 42 can rotate the article 10. In addition, at this time, the rotatable axes of the article 10 (for example, in this embodiment, the three axes of x, y and z centered on the center of gravity of the bolt member) may be set based on the contents of the user's input, taking into account the shape of the article 10, etc.

In step S2, the control unit 60 detects the current posture of the item 10 placed on the item placement unit 2 based on the image data acquired from the imaging unit 50.

In step S3, the control unit 60 calculates the difference between the current attitude and the target attitude for the three rotational axes x, y, and z of the article 10 (i.e., the difference between the roll angle, pitch angle, and yaw angle).

In step S4, the control unit 60 sets the rotation axis to be used to change the position of the item 10 from the current position to the target position based on the difference between the current position and the target position, and sets the target amount of rotation based on the rotation axis to be used.

In step S5, the control unit 60 aligns a coordinate system that specifies the posture of the article 10 (here, the three rotational axes x, y and z of the article 10) with a coordinate system that specifies the holding means side rotation axis of the robot hand 40 (here, the world coordinate system that specifies the direction of the P axis and Q axis).

In step S6, the control unit 60 determines the position-changing holding means from among the holding means 41, 42 by identifying the correspondence between the rotation axis to be used set in the rotation axis setting unit 62 and the holding means-side rotation axis by which each of the holding means 41, 42 can rotate the article 10. In addition, at this time, the control unit 60 determines the amount of rotation using the position-changing holding means to be the target amount of rotation set in the rotation axis setting unit 62.

In step S7, the control unit 60 determines the holding means for pickup based on information such as the placement state of the item 10 placed on the item placement unit 2, the holding method of the item 10 by each of the holding means 41, 42, the contact state with the item 10 when each of the holding means 41, 42 holds the item 10, and the movable range when each of the multiple holding means 41, 42 approaches the item 10.

In step S8, the control unit 60 determines the transfer operation of the item 10 from the pick-up holding means to the position-changing holding means. This transfer operation is, for example, an operation related to the rotation and/or lifting of the pick-up holding means and/or the position-changing holding means (see Figures 8A to 8C).

In step S9, the control unit 60 determines the transfer operation of the item 10 from the position-changing holding means to the position-changing holding means. This transfer operation is, for example, an operation related to the rotation and/or elevation of the position-changing holding means and/or the position-changing holding means, similar to the transfer operation of the item 10 from the pick-up holding means to the position-changing holding means.

Furthermore, after step S9, the control unit 60 may perform a process to determine the operation to be performed when placing the item 10 on the placement target 20 using the place holding means.

Through the series of processes performed by the control unit 60 as described above, the item removal system 1 removes the item 10 from the group of items 10W placed on the item placement unit 2, changes the position of the item 10, and places the item 10 on the placement target 20.

[effect]
As described above, the control device 60 of the robot hand 40 according to this embodiment:
A posture detection unit 61 for detecting a current posture of the article 10;
a rotation axis setting unit 62 that sets an article-side rotation axis to be used when changing the article 10 from a current attitude to a target attitude based on a current attitude of the article 10 set in the attitude detection unit 61 and a target attitude of the article 10 at the time of placement, and a target rotation amount based on the article-side rotation axis;
an operation plan determination unit 63 that determines an operation plan for the holding means 41, 42 for changing the article 10 from a current posture to a target posture based on article information related to the article side rotation axis and the target rotation amount set in the rotation axis setting unit 62 and holding means information related to the holding means side rotation axis by which the holding means 41, 42 can rotate the article 10;
has.

Therefore, according to the control device 60 of the robot hand 40 of this embodiment, even if the items 10 are placed in a bulk state on the item placement section 2, it is possible to take out the items 10 one by one from the item placement section 2, change them to the target posture, and then place them on the installation target 20.

Second Embodiment
FIG. 11 is a diagram showing the configuration of a robot hand 40 according to the second embodiment.

The robot hand 40 according to this embodiment differs from the robot hand 40 according to the first embodiment in that, in addition to a suction head 41 and a gripping member 42 (hereinafter referred to as a "first gripping member 42"), the robot hand 40 has a second gripping member 43 as holding means 41, 42 for rotatably holding an item 10. Note that a description of the configuration common to the first embodiment will be omitted (the same applies to the other embodiments below).

The robot hand 40 according to the first embodiment has only the suction head 41 and the first gripping member 42 as the holding means 41, 42, so the rotation direction when changing the posture of the article 10 is limited to around the Q axis and the P axis. Furthermore, in the robot hand 40 according to the first embodiment, when the gripping member 42 picks up the article 10 from the article placement section 2, it is difficult to pick up the article 10 in a horizontal direction other than the axial direction of the P axis.

From this perspective, the robot hand 40 according to this embodiment has a second gripping member 43 as the holding means 41, 42 having a rotation axis facing in a direction different from the Q axis and the P axis. The second gripping member 43 is, for example, a gripping member having an R axis facing in a direction perpendicular to the Q axis and the P axis as its rotation axis. The second gripping member 43 is, for example, similar to the first gripping member 42, composed of a pair of arms 43A, 43B. And, like the first gripping member 42, the second gripping member 43 has contact parts rotatably supported at the tips of the pair of arms 43A, 43B, and rotatably holds the item 10 with the contact parts as the rotation axis.

In addition, in the item pick-up system 1 according to this embodiment, the control unit 60 is configured to recognize that the robot hand 40 has three holding means 41, 42, 43, namely, the suction head 41, the first gripping member 42, and the second gripping member 43, and to determine an operation plan using these three holding means 41, 42, 43. That is, the memory unit (e.g., ROM) of the control unit 60 stores information on the suction head 41, the first gripping member 42, and the second gripping member 43 as holding means information, and the control unit 60 (operation plan determination unit 63) determines the position-changing holding means, the pick-up holding means, and the transfer operation of the item 10 from the position-changing holding means to the pick-up holding means based on the information.

As described above, the item picking system 1 according to this embodiment makes it possible to change the posture of the item 10 more flexibly, and the item picking system 1 according to this embodiment makes it possible to select from a wider variety of holding means an effective holding means for picking up the item 10 (e.g., a holding means that has a low rate of the item 10 falling out when held) and an effective holding means for changing the posture (e.g., a holding means that can reduce unnecessary movements of the robot arm 30 and the robot hand 40).

This makes it possible to improve the work efficiency of the process from picking up the item 10 from the item placement section 2 to changing it to the target posture and placing it on the installation target 20.

Third Embodiment
12A and 12B are diagrams showing the configuration of a robot hand 40 according to the third embodiment. Note that Fig. 12A and Fig. 12B are enlarged views showing the configuration of an article moving mechanism 44 of a gripping member 42.

The robot hand 40 according to this embodiment differs from the robot hand 40 according to the first embodiment in that the holding means 41, 42 (here, the gripping member 42) have an item moving mechanism 44 that can move the holding position of the item 10 within a predetermined range so as to align the use rotation axis of the item 10 with the holding means side rotation axis while holding the item 10.

In the robot hand 40 according to the first embodiment, the rotation axes (P-axis and Q-axis) of the holding means 41, 42 are fixed, and if the posture of the article 10 placed on the article placement section 2 is not along the axial direction of the P-axis and/or Q-axis, the posture of the article 10 when held by the holding means 41, 42 may be tilted from the axial direction of the rotation axes of the holding means 41, 42. As a result, when the article 10 is held by the holding means 41, 42, the rotation axis (P-axis or Q-axis) of the holding means 41, 42 may be misaligned with the rotation axis (x-axis, y-axis or z-axis) used on the article 10 side (see, for example, FIG. 12A).

From this perspective, the robot hand 40 according to this embodiment is configured such that the gripping member 42 has an item moving mechanism 44 for offsetting the holding position of the item 10. The item moving mechanism 44 may have any configuration, but is, for example, configured by spherical motors 44A, 44B with elastic members 44Aa, 44Ba.

More specifically, the article moving mechanism 44 according to this embodiment is realized by spherical motors 44A, 44B with elastic members 44Aa, 44Ba provided on the inside of the contact portions 42Aa, 42Ba of the pair of arms 42A, 42B that constitute the gripping member 42. Here, the spherical motors 44A, 44B are capable of vertically shifting the elastic members 44Aa, 44Ba, which are members that come into contact with the article 10.

That is, the contact portions 42Aa, 42Ba of the pair of arms 42A, 42B clamp the article 10 from both sides via the elastic members 44Aa, 44Ba. In this state, for example, the spherical motor 44A of one arm 42A moves the position of the elastic member 44Aa upward, and the spherical motor 44B of the other arm 42B moves the position of the elastic member 44Ba downward. This causes the elastic members 44Aa and 44Ba to elastically deform, and the holding angle of the article 10 held between the elastic members 44Aa and 44Ba is tilted from the original state (FIG. 12A) toward the horizontal side (FIG. 12B). That is, this makes it possible to align the position of the use rotation axis (here, the x-axis) of the article 10 with the position of the rotation axis of the gripping member 42 (here, the P-axis).

The operation of the article moving mechanism 44 is controlled by the control unit 60, similar to other components of the robot hand 40. The control unit 60 detects the posture of the article 10 held by the holding means 41, 42 based on image data obtained from the imaging unit 50, for example, and determines whether the holding means side rotation axis and the use rotation axis are misaligned. If the holding means side rotation axis and the use rotation axis are misaligned, the control unit 60 operates the article moving mechanism 44 to align the use rotation axis with the holding means side rotation axis (see FIG. 12B). Then, the control unit 60 executes an operation to change the posture of the article 10 in the holding means 41, 42 with the use rotation axis aligned with the holding means side rotation axis. Note that the memory unit (e.g., ROM) of the control unit 60 stores in advance the mechanism information of the article moving mechanism 44, and the control unit 60 controls the operation of the article moving mechanism 44 based on the mechanism information.

As described above, the item pick-up system 1 according to this embodiment makes it possible to change the posture of the item 10 more flexibly. This makes it possible to more accurately match the posture of the item 10 when the posture is changed by the holding means 41, 42 to the target posture. This also makes it possible to improve the stability of the holding state of the item 10 by the holding means 41, 42.

Other Embodiments
The present invention is not limited to the above-described embodiment, and various modifications are possible.

In the above embodiment, a bolt member is shown as an example of the item 10, but in the present invention, the item 10 may be any item other than a bolt member, such as an L-shaped fastener, a cap, a cylindrical member attached to part of a rod-shaped member, a cap, etc.

In addition, in the above embodiment, the suction head 41 and the gripping member 42 are shown as an example of the holding means of the robot hand 40, but in the present invention, the configuration of the holding means of the robot hand 40 can be changed in various ways. For example, the robot hand 40 may be composed of only a plurality of gripping members. On the other hand, the holding means of the robot hand 40 is not limited to being multiple, and may be only one. This is because even if the robot hand 40 has only one holding means, the control unit 60 needs to determine an operation plan regarding the approach method of the holding means, etc., depending on the current posture of the article 10.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples given above.

The robot hand control device according to the present disclosure can remove objects placed in various different positions from the object placement section, change their position to a target position, and then hold them.

REFERENCE SIGNS LIST 1 Item pick-up system 2 Item placement unit 10 Item 10W Item group 20 Installation target 30 Robot arm 40 Robot hand 40m Hand base 41 Suction head (holding means)
42 First gripping member (holding means)
42A, 42B Arm 43 Second gripping member (holding means)
44: Article moving mechanism 50: Imaging unit 60: Control unit 61: Attitude detection unit 62: Rotation axis setting unit 63: Operation plan determination unit

Claims (12)

A control device for a robot hand having a holding means for rotatably holding an object, comprising:
a posture detection unit for detecting a current posture of the article;
a rotation axis setting unit that sets, for the article, an article-side rotation axis to be used when changing the article from the current orientation to the target orientation based on the current orientation of the article and the target orientation of the article at the time of placing, and a target rotation amount based on the article-side rotation axis;
an operation plan determination unit that determines an operation plan for the holding means for changing the article from the current position to the target position based on article information related to the article side rotation axis and the target rotation amount, and holding means information related to the holding means side rotation axis by which the holding means can rotate the article;
Equipped with
the robot hand has a plurality of holding means each of which holds an object and has holding means-side rotation shafts which face in different directions;
the operation plan determination unit determines, as the operation plan, a posture changing holding means to be used for changing the article from the current posture to the target posture, among the plurality of holding means, based on the article information and the holding means information.
Control device. the operation plan of the holding means is determined based on the current posture of the article detected by the posture detection unit when the article is placed on the article placement unit.
The control device according to claim 1 . the operation plan of the holding means is determined based on the current posture of the article detected by the posture detection unit when the article is picked up from the article placement unit by the holding means.
The control device according to claim 1 . The plurality of holding means include three holding means whose respective holding means side rotation axes are oriented in directions perpendicular to each other.
The control device according to claim 1 . At least two of the plurality of holding means hold the article in different holding methods.
The control device according to claim 1 . The plurality of holding means include
a suction head that holds the article by suctioning the article with its tip and has a holding means side rotation shaft that faces in a vertical direction;
A gripping member that holds the article by pinching both side surfaces of the article and has a holding means side rotation axis that faces a horizontal direction.
The control device according to claim 5 . the operation plan determination unit determines, as the operation plan, an operation of the picking holding means and/or the attitude changing holding means when transferring the item from the picking holding means to the attitude changing holding means, based on the item information and the holding means information of the picking holding means to be used among the plurality of holding means and the attitude changing holding means determined to be used.
The control device according to claim 1 . The operation of the picking holding means and/or the attitude changing holding means when transferring the item from the picking holding means to the attitude changing holding means includes an operation related to a rotation stop position and/or a lift stop position of the picking holding means and/or the attitude changing holding means.
The control device according to claim 7 . The operation plan determination unit determines, as the operation plan, a picking holding means to be used when picking the item from the item placement section, from among the plurality of holding means, based on at least one of information regarding the placement state of the item to be removed, the holding method of the item for each of the plurality of holding means, the contact state of the item for each of the plurality of holding means when holding the item, or the movable range of each of the plurality of holding means when approaching the item.
The control device according to claim 1 . the holding means has an article moving mechanism capable of moving a holding position of the article within a predetermined range so as to align the article side rotation axis of the article with the holding means side rotation axis while holding the article,
the operation plan determination unit determines, as the operation plan, an operation of the article moving mechanism based on the current posture of the article detected when the article is picked up by the holding means from the article placement unit.
The control device according to claim 1 . The holding means is a gripping member that holds the article by pinching both side surfaces of the article and has a holding means side rotation shaft that faces a horizontal direction,
The article moving mechanism is constituted by a spherical motor with an elastic member provided at a position on the inner side surface of the gripping member where the spherical motor comes into contact with the article.
The control device according to claim 10 . An article pick-up system comprising a control device according to any one of claims 1 to 11 .

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