JP2008178930A - Workpiece gripping method of robot and robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a workpiece gripping method of a robot and the robot capable of speedily passing a workpiece from one hand to the other and simplifying a facility. <P>SOLUTION: This robot 1 is furnished with the hands 4 to grip the workpiece 10 of an object, a robot main body part 2 to move these hands 4 to positions and postures designated in a three-dimensional space and a robot control device 5 to control the positions and the postures of the hands 4 by driving this robot main body part 2. It is devised to release the workpiece 10 in the air from one of the hands 4 and to catch and grip this workpiece 10 released in the air by the other hand 4 under the workpiece gripping method of the robot 1 to grip the workpiece 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a robot workpiece gripping method and a robot that grips a workpiece that is an object, and more particularly, to a robot workpiece gripping method capable of quickly changing workpieces and simplifying equipment. And robots.

  Conventionally, as a workpiece supply method using a robot, there is known a method in which a target workpiece is aligned using a parts feeder, supplied in a posture in which the workpiece can be gripped, and a robot hand grips the workpiece. In addition, a method in which a target work is aligned by a person or an aligning device so that the target work can be gripped on a pallet, the work is supplied by the pallet, and this work is gripped by a robot hand is also well known. . However, these methods have problems such as a large equipment for a work with a small amount of material and poor storage efficiency.

  On the other hand, there has been proposed a method of measuring the position and posture of a work that can be held using a camera from a plurality of stacked work pieces, and holding and taking out the work with a robot hand (see, for example, Patent Document 1). .

However, since the workpiece is gripped in a state where the posture is not adjusted, there is a case where the part of the workpiece to be gripped cannot always be gripped, and the workpiece needs to be changed. In order to change the workpiece, many methods are employed in which the workpiece is temporarily placed on a temporary placement table, the workpiece posture is measured by a visual sensor, and the workpiece is gripped again. In addition, a method has been proposed in which a dedicated jig is used to change the posture of the workpiece without changing the weight of the workpiece on the robot and to change the workpiece (for example, see Patent Document 2).
JP 2004-82232 A JP 2005-81442 A

  By the way, especially when gripping a work with a small amount of material, it may not be possible to grip the part of the work to be gripped by using a method of gripping an unaligned work, and it is necessary to change the work. . A typical example of the method of changing the workpiece is a method in which the workpiece is temporarily placed on a temporary table by gripping it from the hand, and the workpiece is temporarily placed on the table. It may not be gripped because it is in contact with the table, which is not perfect. In such a case, there is a method of creating a posture of a work that can be gripped by moving the work, but there is a problem that the operation of the robot increases and it takes time to change the work.

  There is also a way to create a gap where the hand claw can be inserted at the position where the workpiece should be gripped while the workpiece is temporarily placed, but the shape of the temporary table becomes complicated. There is a problem that it is difficult to make a shape corresponding to the workpiece.

  An object of the present invention is to provide a robot workpiece gripping method and a robot capable of quickly changing workpieces and simplifying equipment in view of the above-described conventional situation.

In order to solve the above problems, a robot workpiece gripping method according to the present invention includes a hand that grips a workpiece that is an object, a robot body that moves the hand to a specified position and posture in a three-dimensional space, In a workpiece gripping method for a robot that grips the workpiece using a robot having a robot control device that controls the position and posture of the hand by driving the robot body, the workpiece is released into the air, The workpiece released in the above is captured and held with the above hand so that it can be changed.

Further, it is preferable that the workpiece is dropped and released into the air, and the workpiece in the middle of dropping is captured and held by the hand and changed.
Further, it is preferable that the work is dropped by the hand and released into the air, and the hand that has been dropped is captured and held again by the hand that dropped the work.

Further, it is preferable that the work is thrown up and released into the air, and the work released in the air is captured and held by the hand and held.
Also, the workpiece that is being thrown up and dropped may be captured and held by the hand and then moved.

  Further, it is preferable that the work is thrown up by the hand and released into the air, and the work released in the air is captured and held again by the hand that has dropped the work.

Further, it is preferable to determine the posture before release of the workpiece so that the workpiece is released into the air in a posture that allows easy gripping.
In order to solve the above-described problems, a robot according to the present invention includes a hand that holds a workpiece that is an object, a robot main body that moves the hand to a specified position and posture in a three-dimensional space, and the robot main body. And a robot control device that controls the position and posture of the hand by driving the robot, the robot control device determines a position and posture for capturing and gripping the work released in the air, The workpiece is captured and held at the position and posture determined by the robot control device, and the workpiece is held.

Further, the hand may be configured to drop the work and release it into the air, and to capture and hold the work released into the air.
The hand may be configured to throw up the work and release it in the air, and to capture and hold the work released in the air and hold it.

  In the present invention, since the work is released into the air, and the work released in the air is captured and held by the hand, the work is changed using a temporary table or a jig for changing the posture of the work. There is no need to do. Therefore, according to the present invention, it is possible to quickly change the workpiece and simplify the equipment.

  Further, according to the present invention, since it is not necessary to use a temporary table or the like, it is possible to make it difficult to be restricted by the shape of the target workpiece.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
FIG. 1 is a schematic configuration diagram showing a robot according to a first embodiment of the present invention.

In the figure, a robot 1 includes a robot body 2, an articulated arm 3 connected to the robot body 2, and a hand 4 that is provided at the tip of the arm 3 and grips a workpiece 10.
And a robot controller 5 that is electrically connected to the robot body 2 and drives the robot body 2 to control the position and posture of the hand 4.

  The arm 3 is composed of a first joint 3 a provided with a hand 4 at the tip, and a second joint 3 b connected to the other end of the first joint 3 a and the robot body 2. With this configuration, the arm 3 can move the hand 4 to an arbitrary position in the space within the operation area.

The hand 4 is provided so as to be adjustable in angle with respect to the first joint 3a so that the workpiece 10 can be gripped in a desired posture.
The robot control device 5 is connected to a visual device 6 that puts the operation area of the hand 4 into the field of view, and the measurement result of the visual device 6, that is, the position and posture of the hand 4 are transmitted from the visual device 6. As will be described in detail later, the robot controller 5 determines the optimal gripping position, gripping posture, and gripping time of the workpiece 10 by predicting the trajectory after the workpiece 10 is dropped, for example, by sequence control. It is possible to change the work 10 by controlling the position and posture of the hand 4 to capture and hold the falling work 10.

2A, 2B and 2C are a perspective view, a front view and a side view showing the workpiece according to the first embodiment, respectively.
The workpiece 10 has a substantially cylindrical shape as shown in FIG. 2A, and two gripping surfaces 10a and 10a facing each other are formed at the end of the curved surface. These two grip surfaces 10a, 10a are formed in a rectangular plane that is recessed from the curved surface in order to facilitate gripping by the hand 4.

FIG. 3 is a flowchart showing the workpiece transfer operation of the robot according to the first embodiment.
First, the robot control device 5 shown in FIG. 1 detects the gripping posture of the workpiece 10 from the visual device 6, and determines whether or not the holding of the workpiece 10 by the hand 4 is necessary (S1). Specifically, as shown in FIGS. 4A and 4B (an explanatory diagram showing a state where the gripping surface 10a of the workpiece 10 is gripped), when the hand 4 is gripping the gripping surface 10a of the workpiece 10, the workpiece It is determined that there is no need to carry out 10 changes. Further, as shown in FIGS. 5A and 5B (an explanatory diagram showing a state in which the gripping surface of the workpiece 10 is not gripped), when the hand 4 does not grip the gripping surface 10a of the workpiece 10, the workpiece 10 Judge that it is necessary to change.

6A to 6D are explanatory views showing the workpiece transfer operation of the robot according to the first embodiment.
When the robot control device 5 determines that the workpiece 10 needs to be changed, the robot control device 5 detects the gripping position and gripping posture of the workpiece 10 in the state before dropping shown in FIG. The trajectory after the fall is predicted (S2). In this trajectory prediction, it is necessary to predict a trajectory according to time.

  Next, based on the trajectory prediction result, it is determined whether or not the hand 4 can grip the workpiece 10 based on the movable speed of the arm 3 or the like (S3). Specifically, when the workpiece 10 is dropped, it is determined whether or not the workpiece 10 does not come into contact with other members such as a base portion (not shown) disposed below the robot 1 before being captured and held by the hand 4. judge. At this time, the optimum position, posture and time for the hand 4 to grip the gripping surface 10a of the workpiece 10 may be determined.

  If it is determined by the above determination (S3) that the capture and gripping by the hand 4 is not successful, that is, the workpiece 10 is in contact with another member, the arm 3 is moved and the hand 4 is moved upward, for example, 4 to change the gripping position of the workpiece 10 (S4).

  Then, as shown in FIG. 6B, the gripping of the workpiece 10 by the hand 4 is released, and the workpiece 10 is dropped and released into the air (S5). The work 10 may be released to the operation area of the arm 3 (hand 4) by another device or the like without being released by the hand 4.

  When the workpiece 10 is falling, the hand 4 (arm 3) is moved as shown in FIG. 6C, and the hand 4 is moved as shown in FIG. 6D at the position, posture and time determined by the robot controller 5. Thus, the workpiece 10 is captured and held (S6). As a result, as shown in FIGS. 4A and 4B, the hand 4 grips the gripping surface 10a of the work 10, and the holding of the work 10 ends.

  In the present embodiment, the workpiece 10 has been described as having a substantially cylindrical shape. However, the shape of the workpiece of the present invention is not limited to a substantially cylindrical shape, as long as it is a shape that can be gripped by any hand. Therefore, the workpiece of the present invention does not necessarily have the flat gripping surface 10a. Further, the shape of the hand of the present invention is not limited as long as it is a shape capable of gripping some work.

  In the present embodiment described above, the workpiece 10 is released into the air, and the workpiece 10 released into the air is captured and held by the hand 4 and is then transferred. There is no need to change the workpiece 10 using tools or the like. Therefore, according to this embodiment, the workpiece 10 can be quickly changed and the equipment can be simplified. Furthermore, since it is not necessary to use a temporary table or the like, it is possible to make it difficult to be restricted by the shape of the target workpiece 10.

  According to the present embodiment, since the workpiece 10 is released into the air by dropping the workpiece 10, the trajectory of the workpiece 10 can be easily predicted, and the workpiece 10 can be changed more accurately.

  Moreover, according to this embodiment, since the workpiece 10 in the middle of dropping is captured and held again by the hand 4 that has dropped the workpiece 10, an apparatus for dropping the workpiece 10 or the like becomes unnecessary, and the facilities can be simplified. Can be planned.

Second Embodiment
This embodiment is different from the first embodiment only in that the workpiece 10 is not dropped and released into the air, but is thrown up and released into the air, and therefore corresponds to S1 to S4 of the first embodiment. Description of S11 to S14 is omitted.

FIG. 7 is a flowchart showing the workpiece transfer operation of the robot according to the second embodiment of the present invention.
FIG. 8A to FIG. 8D are explanatory views showing the workpiece transfer operation of the robot according to the second embodiment.

  First, similarly to the first embodiment, when it is necessary to change the workpiece 10 (S11), the trajectory of the workpiece is predicted (S12), and it is confirmed that the workpiece 10 can be captured and held (S13). , 14). Further, the optimum position, posture and time for the hand 4 to grip the gripping surface 10a of the workpiece 10 are determined.

Then, from the state shown in FIG. 8A, the work 10 is thrown up by the hand 4 as shown in FIG. 8B and released into the air (S15). Note that the workpiece 10 may not be thrown up by the hand 4, but may be dropped into the operation area of the arm 3 (hand 4) by another device, for example. Also, it is desirable to throw the workpiece 10 upward in the vertical direction because it is easy to predict the trajectory by the robot controller 5, but the ease of movement of the arm 3 (for example, when it is sufficient to move only the first joint 3a), etc. It may be thrown up obliquely in consideration. Furthermore, it is also effective to throw up the workpiece 10 with the hand 4 facing in the direction in which the workpiece 10 is thrown up in order to prevent the workpiece 10 from rotating after being released.

  When the workpiece 10 is falling, the hand 4 (arm 3) is moved as shown in FIG. 8C, and the hand 4 is moved at the position, posture and time determined by the robot controller 5 as shown in FIG. 8D. Thus, the workpiece 10 is captured and held (S16). Thereby, the hand 4 comes to hold | grip the holding surface 10a of the workpiece | work 10, and the holding change of the workpiece | work 10 is complete | finished. In addition, you may hold | grip the workpiece | work 10 when it is thrown up and moving upwards, without gripping it during fall.

  In the present embodiment described above, the workpiece 10 is released into the air, and the workpiece 10 released into the air is captured and held by the hand 4 and is then transferred. There is no need to change the workpiece 10 using tools or the like. Therefore, according to this embodiment, the workpiece 10 can be quickly changed and the equipment can be simplified. Furthermore, since it is not necessary to use a temporary table or the like, it is possible to make it difficult to be restricted by the shape of the target workpiece 10.

  Further, according to the present embodiment, the work 10 is thrown up, released into the air, and captured and gripped by the hand 4. Therefore, the time until the work 10 is gripped can be increased, and the work 10 can be easily captured and gripped. Can be.

  In addition, according to the present embodiment, since the workpiece 10 that is being thrown up and being dropped is captured and gripped, the time until the workpiece 10 is gripped can be further increased, and the workpiece 10 can be captured and gripped more easily. Can do.

  Further, according to the present embodiment, since the holding is performed by capturing and gripping the workpiece 10 again with the hand 4 that has thrown up the workpiece 10, a device for lifting the workpiece 10 or the like becomes unnecessary, and the facilities are simplified. Can be achieved.

<Third Embodiment>
Since this embodiment has a feature in the step of changing the posture of releasing the workpiece 10 into the air, the other steps are the same as those in the first or second embodiment.

FIG. 9 is an explanatory view showing the gripping posture before the change of the workpiece according to the third embodiment of the present invention, FIG. 10 is the gripping posture after the change, and FIG. 11 is the gripping posture at the time of capture.
As shown in FIG. 9, when the gripping surface 10 a of the workpiece 10 is tilted from the vertical direction, the workpiece 10 remains tilted even when the workpiece 10 is captured and gripped, or falls while rotating. Therefore, the robot controller 5 described in the first and second embodiments determines the posture before the workpiece 10 is released by calculation so that the workpiece 10 can be easily gripped. And as shown in FIG. 10, the hand 4 is inclined and the holding | grip attitude | position of the workpiece | work 10 is changed so that the holding surface 10a may follow a vertical direction here.

  By adding the above steps to the first embodiment or the second embodiment, as shown in FIG. 11, the gripping surface 10 a is along the vertical direction even during capture gripping. The workpiece 10 can be easily held. Therefore, according to this embodiment, in addition to the effect of the said 1st Embodiment or the said 2nd Embodiment, the holding | maintenance of the workpiece | work 10 can be performed more correctly.

1 is a schematic configuration diagram illustrating a robot according to a first embodiment of the present invention. It is a perspective view which shows the workpiece | work which concerns on the said 1st Embodiment. It is a front view which shows the workpiece | work which concerns on the said 1st Embodiment. It is a side view which shows the workpiece | work which concerns on the said 1st Embodiment. It is a flowchart which shows the workpiece transfer operation | movement of the robot which concerns on the said 1st Embodiment. It is explanatory drawing (front view) which shows the state which hold | gripped the holding surface of the workpiece | work which concerns on the said 1st Embodiment. It is explanatory drawing (side view) which shows the state which hold | gripped the holding surface of the workpiece | work which concerns on the said 1st Embodiment. It is explanatory drawing (front view) which shows the state which is not holding the holding surface of the workpiece | work which concerns on the said 1st Embodiment. It is explanatory drawing (side view) which shows the state which is not holding the holding surface of the workpiece | work which concerns on the said 1st Embodiment. It is explanatory drawing (the 1) which shows the workpiece transfer operation | movement of the robot which concerns on the said 1st Embodiment. It is explanatory drawing (the 2) which shows the workpiece transfer operation | movement of the robot which concerns on the said 1st Embodiment. It is explanatory drawing (the 3) which shows the workpiece transfer operation | movement of the robot which concerns on the said 1st Embodiment. It is explanatory drawing (the 4) which shows the workpiece transfer operation | movement of the robot which concerns on the said 1st Embodiment. It is a flowchart which shows the workpiece transfer operation | movement of the robot which concerns on 2nd Embodiment of this invention. It is explanatory drawing (the 1) which shows the workpiece transfer operation | movement of the robot which concerns on the said 2nd Embodiment. It is explanatory drawing (the 2) which shows the workpiece transfer operation | movement of the robot which concerns on the said 2nd Embodiment. It is explanatory drawing (the 3) which shows the workpiece transfer operation | movement of the robot which concerns on the said 2nd Embodiment. It is explanatory drawing (the 4) which shows the workpiece transfer operation | movement of the robot which concerns on the said 2nd Embodiment. It is explanatory drawing which shows the holding | grip attitude | position before the change of the workpiece | work concerning 3rd Embodiment of this invention. It is explanatory drawing which shows the holding | grip attitude | position after the change of the workpiece | work concerning the said 3rd Embodiment. It is explanatory drawing which shows the holding | grip attitude | position at the time of the capture | acquisition of the workpiece | work which concerns on the said 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot 2 Robot main-body part 3 Arm 4 Hand 5 Robot control apparatus 6 Visual apparatus 10 Work 10a Gripping surface

Claims (10)

A hand that grips a workpiece that is an object, a robot main body that moves the hand to a specified position and posture in a three-dimensional space, and a robot that controls the position and posture of the hand by driving the robot main body In a workpiece gripping method for a robot that grips the workpiece using a robot provided with a control device,
Release the workpiece into the air,
A method for gripping a workpiece of a robot, wherein the workpiece released into the air is captured and held by the hand and then held. Drop the workpiece and release it into the air,
2. The robot workpiece gripping method according to claim 1, wherein the workpiece in the middle of dropping is captured and held by the hand and then changed. The work is dropped by the hand and released into the air,
3. The robot workpiece gripping method according to claim 2, wherein the workpiece that has been dropped is captured and held again by the hand that has dropped the workpiece. Throw the workpiece and release it into the air,
2. The robot workpiece gripping method according to claim 1, wherein the workpiece released into the air is captured and held by the hand and then held.   The work gripping method according to claim 4, wherein the workpiece that is being thrown up and dropped is captured and held by the hand to be held. Throw the work with the hand and release it into the air,
5. The robot workpiece gripping method according to claim 4, wherein the workpiece released into the air is captured and held again by the hand that has dropped the workpiece.   The robot workpiece gripping method according to claim 1, wherein the posture before the workpiece is released is determined so that the workpiece is released into the air in a posture that allows the workpiece to be easily gripped. A hand that grips a workpiece that is an object, a robot main body that moves the hand to a specified position and posture in a three-dimensional space, and a robot that controls the position and posture of the hand by driving the robot main body In a robot comprising a control device,
The robot control device determines a position and posture for capturing and gripping the workpiece released into the air;
The robot according to claim 1, wherein the hand captures and holds the workpiece at a position and posture determined by the robot control device.   The robot according to claim 8, wherein the hand drops the work to release it into the air, and captures and holds the work released into the air.   The robot according to claim 8, wherein the hand throws up the work and releases it in the air, and captures and holds the work released in the air and holds it.

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