JP2014108496A - Workpiece positioning method by multi-joint robot and workpiece attachment method by multi-joint robot using the workpiece positioning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a workpiece positioning method for efficiently controlling the position and attitude of a workpiece placed at a random position in a random attitude by a simple tool and simple operation.SOLUTION: A workpiece positioning method by a multi-joint robot including steps of: setting a predetermined region of a workpiece arranged at a random position in a random attitude to a reference portion in advance when picking up the workpiece by a hand of the multi-joint robot and positioning the workpiece at a predetermined position in a predetermined attitude; providing a holding tool holding the workpiece rotatably around an axis of the reference portion as the hand; further providing an abutment tool of a predetermined size and a predetermined shape at a predetermined position relative to the robot; holding first the workpiece rotatably around the axis of the reference portion using the holding tool; moving next the holding tool while abutting the workpiece on the abutment tool, and rotating the workpiece until the workpiece has the predetermined attitude around the axis of the reference portion; and moving then the holding tool, and arranging the workpiece at the predetermined position.

Description

  The present invention relates to a method for picking up a workpiece arranged at a random position and posture by a hand (end effector) of an articulated robot and positioning it at a predetermined position and posture, and an articulated robot using the workpiece positioning method. It is related with the workpiece | work mounting method by.

  For example, in the work by the dual-arm robot which is a kind of articulated robot previously disclosed in Patent Document 1 by the applicant of the present application, separate works are held with their hands, combined, and fastened with screws or the like. There is work to do. In addition, an ordinary single-arm industrial robot, which is a kind of articulated robot, also has a work of holding a work with the single arm and mounting and fixing it on another work on the table.

  There are cases where these workpieces are arranged in advance and stored in a box, and cases where the workpieces are stacked in random positions and postures. When the workpieces are aligned in advance, a separate process for aligning the workpieces in advance is required, but recognition of the posture of the workpiece by the robot is unnecessary, and gripping by the robot is relatively simple. On the other hand, when the workpieces are piled up at random positions and postures, the robot needs to determine the position and posture of the workpieces using a sensor such as a camera and determine the grip location.

  Here, after recognizing the position and posture of the workpiece, the following procedure is required to grip the workpiece and align and arrange it at a desired position and posture. That is, if the robot has a sufficient degree of freedom, a movable range, and an operation accuracy, after the workpiece is gripped, the position and posture of the workpiece are controlled as they are, and the arrangement is arranged. If the above conditions are not satisfied, after gripping the workpiece, the workpiece is temporarily placed in a temporary storage area, the workpiece is positioned at a predetermined position and posture, and then the workpiece is again gripped and aligned.

JP 2010-064198 A

  In work using an articulated robot, it is extremely difficult to realize all arm postures necessary for work due to limitations by freedom and joint angle limits and various obstacles in the work area. For this reason, conventionally, it has been necessary to deal with the problem by means such as increasing the degree of freedom of the arm or changing the work after placing the work once. In either case, it was necessary to strictly measure both the “position” and “posture” of the workpiece.

  Therefore, the present invention relates to a workpiece positioning method for efficiently controlling the position and posture of a workpiece placed at a random position and posture with a simple jig and simple operation, and an articulated type using the workpiece positioning method. The purpose is to provide a method for mounting a work by a robot.

  The present invention advantageously solves the above-described problem, and the work positioning method by the articulated robot according to the present invention takes a work placed at a random position and posture by a hand of the articulated robot and performs predetermined processing. When positioning in the position and orientation, a predetermined part of the workpiece is set as a reference portion in advance, and a holding jig is provided as the hand to hold the workpiece so as to be rotatable around the axis of the reference portion. A contact jig having a predetermined size and shape is provided at a predetermined position with respect to the robot, and first, the work is held by the holding jig so as to be rotatable around the axis of the reference portion. The holding jig is moved while abutting against the abutting jig to rotate the workpiece around the axis of the reference portion until it reaches a predetermined posture. It is characterized in that the jig is moved to place the workpiece in a predetermined position.

  In the work mounting method using the articulated robot according to the present invention, the articulated robot is a double-arm robot, and the double-arm robot positions the work with the holding jig as a hand of one arm. The workpiece is mounted and fixed to another workpiece with a tool as the hand of the other arm while positioning by the method.

  According to the work positioning method by the articulated robot of the present invention described above, when the work placed at a random position and posture is picked up by the hand of the articulated robot and positioned at a predetermined position and posture, A predetermined part of the workpiece is set as a reference portion, and a holding jig is provided as the hand to hold the workpiece so as to be rotatable around the axis of the reference portion. An abutting jig is provided, and first, the work is held by the holding jig so as to be rotatable around the axis of the reference portion, and then the dimension shape of the abutting jig and the contour shape of the work Based on the position of the reference portion and the positional relationship between the contact jig and the holding jig, the work is brought into contact with the contact jig before Move the holding jig to rotate the workpiece around the axis of the reference portion until it reaches a predetermined posture, and then move the holding jig to place the workpiece in the predetermined posture at a predetermined position Therefore, even if the position and posture of a workpiece placed at a random position and posture are not strictly measured, the workpiece can be efficiently controlled by a simple jig and simple operation of the robot. It can be positioned in position and orientation.

  In the work positioning method using the articulated robot according to the present invention, the reference portion may be a round hole formed in a predetermined part of the work, and in this way, the round hole is fitted. For example, the workpiece can be easily rotated around the axis of the reference portion by a positioning pin.

  Further, in the work positioning method by the articulated robot according to the present invention, the holding jig may hold the work in a state where a positioning member is fitted to a reference portion of the work. By doing so, for example, by holding the work with a magnet or a suction pad in a state where the positioning member is fitted in a pin as a reference part protruding from the work or a round hole as a reference part formed in the work Alternatively, the workpiece can be easily held by gripping a pin as a reference portion protruding from the workpiece or a round hole as a reference portion formed on the workpiece with a collapsible chuck with a reduced diameter or an increased diameter, for example. And can be held so as to be rotatable around the axis of the reference portion.

  According to the work mounting method using the multi-joint robot of the present invention, the multi-joint robot is a double-arm robot, and the double-arm robot holds the work with the holding jig as a hand of one arm. While positioning by the workpiece positioning method, the workpiece is mounted and fixed to other workpieces with tools such as an electric screwdriver, welding gun, adhesive dispenser, etc. as the other arm's hand. In addition, it is possible to ensure that the work placed in the posture is attached to another work.

In one embodiment of the work mounting method by the multi-joint robot of the present invention using one embodiment of the work positioning method by the multi-joint robot of the present invention, holding treatment of one arm of the multi-joint double-arm robot as a hand It is sectional drawing which shows the state which is trying to carry out the screwing attachment of the plate-shaped workpiece | work which positioned and hold | maintained with the tool to another workpiece | work by the electric driver as a hand of the other arm. It is a flowchart which shows the operation | movement procedure of the multi joint type double arm robot in the workpiece | work positioning method by the multi joint type robot of the said Example. (A), (b) is the reference | standard of the positioning member of a holding jig as a hand of one arm of the multi-joint type double arm robot in the work positioning method by the multi joint type robot of the said Example, and a plate-shaped work It is the front view and top view which show the dimensional relationship with the round hole as a part. In the work positioning method using the multi-joint robot of the above embodiment, the plate-like work held by the holding jig as the hand of one arm of the multi-joint double-arm robot is brought into contact with the cylindrical contact jig. FIG. (A)-(d) is a top view which shows sequentially the positioning procedure of the workpiece | work in the workpiece positioning method by the articulated robot of the said Example. It is sectional drawing which shows another Example of the workpiece | work mounting method by the articulated robot of this invention using another Example of the workpiece positioning method by the articulated robot of this invention. It is sectional drawing which shows further another Example of the workpiece | work mounting method by the articulated robot of this invention which used further another Example of the workpiece positioning method by the articulated robot of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows one embodiment of a multi-joint type double-arm robot in an embodiment of the work mounting method using the multi-joint robot according to the present invention. A cross section showing a state where a plate-like workpiece, whose posture is positioned and held by a holding jig as an arm hand, is screwed to another workpiece by an electric screwdriver as the other arm hand FIG.

  In the work positioning method using the articulated robot of this embodiment and the work mounting method using the articulated robot of this embodiment using the same, for example, the applicant of the present application previously disclosed in Japanese Patent Laid-Open No. 2010-064198 (Patent Document 1). In the figure, reference numeral 1 denotes one arm of the multi-joint double-arm robot, and 2 denotes the other arm of the multi-joint double-arm robot.

  In the work positioning method of this embodiment, the holding jig 4 as a hand attached to the tip of one arm 1 of the multi-joint type double-arm robot via a normal tool changer 3 is faced up on the work table T. By holding and lifting the plate-like workpieces 5 stacked in random positions and postures, the workpieces are brought into contact with the abutting jig 6 that stands vertically at a predetermined position on the work table T. 5 is rotated and positioned in a predetermined posture (orientation) with respect to another workpiece 7 arranged at a predetermined position on the work table T, and then positioned at a predetermined position on the workpiece 7.

  In the workpiece mounting method of this embodiment, the workpiece 5 is positioned at a predetermined position and posture with respect to the other workpiece 7 by the positioning method of the above embodiment, and then the tip of the other arm 2 of the multi-joint type double-arm robot. While holding and rotating the screw 9 by the electric driver 8 as a hand provided in the part, the electric driver 8 is lowered by the other arm 2 and the workpiece 5 held at the predetermined position and posture is set to the other workpiece 7. Secure with screws.

  The articulated double-arm robot used in this embodiment has two video cameras on the head, similar to the one described in the above publication, although not shown, and based on images from these video cameras, the work place As well as recognizing the shape and type of a target object such as a workpiece or workpiece, the three-dimensional position of the target object can be recognized based on the orientation of the video camera and the principle of camera surveying. By teaching the above, it is possible to perform an assembly operation described later according to the type of the object based on the previously given program. Hereinafter, these examples will be described in detail.

  FIG. 2 is a flowchart showing an operation procedure of the articulated double-arm robot in the work positioning method by the articulated robot of the above embodiment. First, in step S1, it is determined whether or not the position of the work 5 is known. If it is known, the process proceeds to step S3. If it is not known, the three-dimensional position of the work 5 on the work table T is recognized from the images from the two video cameras of the head, for example, in step S2. The plate-like workpiece 5 here is made of a ferromagnetic material such as iron or steel, for example, and as shown in FIG. 3B, two penetrating holes as round holes arranged in the longitudinal direction of the workpiece 5 at a predetermined interval. It has holes 5a and 5b, and in this embodiment, the through-hole 5a on the right side of the through-holes 5a and 5b with the both ends of the work 5 facing upwards rounded up is used as a reference portion. Set.

  In step S3, the holding jig 4 is detachably attached to the tip of the arm 1 via the tool changer 3. The holding jig 4 has a base 4 fixed to the tool changer 3 and extends in a plane parallel to the arm 1, and is provided at the tip of the bracket 4a so as to extend perpendicular to the bracket 4a. The support cylinder 4b, a support shaft 4c fitted into the support cylinder 4b via a bush so as to be movable up and down, and having a retaining flange at the upper end, and a screw at the lower end of the support shaft 4c. And a positioning pin 4d having a substantially inverted conical tip and a center hole through which the positioning pin 4d passes, and a collar is provided between the lower end of the support shaft 4c and the positioning pin 4d. An annular permanent magnet 4e sandwiched between them, and a compression spring 4f disposed around the support shaft 4c and interposed between the permanent magnet 4e and the lower end of the support cylinder 4b. Shown in 3 In other words, the maximum outer diameter portion of the distal end portion of the positioning pin 4d has an outer diameter substantially equal to the inner diameter of the through hole 5a of the workpiece 5 so as to be closely slidably fitted to the through hole 5a of the workpiece 5. Yes.

  In subsequent step S4, the work 5 is held by the holding jig 4 so as to be rotatable around the axis of the through hole 5a serving as the reference portion. That is, the positioning pin 4d is aligned with the through hole 5a above the through hole 5a of the arbitrary first work 5 among the plurality of stacked works 5, and the support shaft 4c extends in the vertical direction. The arm 1 is actuated to move the holding jig 4, and then the holding jig 4 is lowered to insert the positioning pin 4 d into the through hole 5 a of the work 5, and the permanent magnet 4 e uses the through hole 5 a of the work 5. As shown in FIG. 4, the work 5 is held by the holding jig 4 so as to be rotatable around the axis of the through hole 5a that coincides with the axis of the support shaft 4c.

  In the subsequent step S5, the arm 1 is operated to lift the holding jig 4 together with the work 5, and as shown in FIGS. 5 (a) to 5 (d), it is moved along a predetermined path in the horizontal plane. First, the posture of the workpiece 5 is positioned in a predetermined direction. That is, first, as shown in FIG. 5A, the holding jig 4 is lifted after holding the arbitrary first work 5 among the plurality of stacked works 5 by the holding jig 4. Then, the workpiece 5 is awaited to a predetermined height lower than the tip of the columnar contact jig 6.

  Next, as shown by a thick arrow in FIG. 5B, the holding jig 4 is moved horizontally so that a predetermined side of the work 5 (side where both ends are not rounded in the illustrated example) is directed to the contact jig 6. As shown in FIG. 5C, the holding jig 4 is brought into contact with the contact jig 6 while the side of the work 5 is in contact with the contact jig 6 (in the illustrated example, both ends of the work 5 are The workpiece 5 is rotated around the axis of the through-hole 5a by horizontally moving the unrounded side to the position where the side extends in the left-right direction).

  The predetermined position of the holding jig 4 with respect to the abutting jig 6 is determined by the positional relationship of the through hole 5a with respect to the side where both ends of the workpiece 5 are not rounded, and the position and outer diameter of the abutting jig 6. Therefore, they are geometrically obtained from them in advance and taught to the double-arm robot together with the movement path.

  As a result, the workpiece 5 is positioned in a predetermined posture (in the illustrated example, the posture in which both ends of the workpiece 5 are not rounded extends in the left-right direction), and in this state, as shown in FIG. The holding jig 4 is moved horizontally to move the workpiece 5 to a position where the two through holes 5a and 5b are aligned with the two screw holes of the other workpiece 7, respectively, and finally the holding jig 4 is moved. As shown in FIG. 1, the workpiece 5 is pressed onto the workpiece 7 at a position and posture in which the two through holes 5a and 5b are aligned with the two screw holes of the other workpiece 7, respectively.

  At this time, when the holding jig 4 is lowered, the support shaft 4c rises while compressing the compression spring 4f in the support cylinder 4b, so that the workpiece 5 is pressed onto the workpiece 7 and positioned by the repulsive force of the compression spring 4f. be able to. In this positioning state, in the work mounting method of this embodiment, the electric driver 8 is lowered by the other arm 2 while being held and rotated by the electric driver 8 and held at the predetermined position and posture. The workpiece 5 is fixed to the other workpiece 7 with screws. Thereafter, the process returns to step S1 in FIG. 2, step S3 is skipped, and the same mounting operation is repeated until the work 5 is exhausted.

  Therefore, according to the workpiece positioning method using the articulated robot of this embodiment, a simple jig and robot can be easily used without strictly measuring the position and posture of a workpiece placed at a random position and posture. The workpiece can be positioned at a predetermined position and posture by efficiently controlling with a simple operation.

  According to the work mounting method using the articulated robot of this embodiment, the double-arm robot positions the work 5 with the holding jig 4 as the hand of one arm 1 by the work positioning method of the above-described embodiment, Since the work 5 is attached and fixed to the other work 7 by the electric driver 8 as the hand of the arm 2, the work 5 placed at a random position and posture on the double-arm robot is attached to the other work 7. Work can be performed reliably.

  FIG. 6 is a cross-sectional view showing another embodiment of the work mounting method using the articulated robot of the present invention using another embodiment of the work positioning method using the articulated robot of the present invention. The workpiece positioning method and workpiece mounting method of the example are different only in that the holding jig 4 has a suction pad 4j instead of the permanent magnet 4e, and the other points are the same as the previous embodiment. Here, the different points will be mainly described.

  That is, the holding jig 4 in the workpiece positioning method and the workpiece mounting method of this embodiment includes a bracket 4a having a base fixed to the tool changer 3 and extending in a plane parallel to the arm 1, and a tip portion of the bracket 4a. A cylinder 4g provided so as to extend perpendicular to the bracket 4a, a pipe 4h for supplying negative pressure air from the arm 1 to the cylinder 4g via the tool changer 3, and an O-ring in the cylinder 4g. And a support shaft 4c fitted in an airtight manner so as to be able to move up and down and turnably and prevented from being removed by a latching screw 4i, and a substantially inverted conical tip end portion fastened with a screw to the lower end portion of the support shaft 4c. The positioning pin 4d, the suction pad 4j that is airtightly fitted to the lower end of the support shaft 4c so as to surround the positioning pin 4d, and the rear end of the positioning pin 4d. Provided, it has an annular gasket 4k larger outer diameter the distal end, and a compression spring 4f interposed between the support shaft 4c and the cylinder 4g.

  Here, the maximum outer diameter portion of the distal end portion of the positioning pin 4d has an outer diameter substantially equal to the inner diameter of the through hole 5a of the work 5 so as to be closely slidably fitted to the through hole 5a of the work 5. ing. In addition, an air passage is formed in the support shaft 4c for communicating negative pressure air inside the suction pad 4j by communicating the inside of the cylinder 4g and the suction pad 4j.

  According to the holding jig 4, the maximum outer diameter portion of the tip end portion of the positioning pin 4d is closely fitted in the through hole 5a as the reference portion of the work 5, and the axes of the through hole 5a and the support shaft 4c are aligned. In this state, while the annular gasket 4k prevents air leakage from the through hole 5a, the portion around the through hole 5a of the work 5 is adsorbed by the negative pressure air inside the suction pad 4j, thereby supporting the cylinder 4g. By rotating 4c, the workpiece 5 can be held so as to be rotatable about the axis of the through hole 5a. When the holding jig 4 is lowered, the support shaft 4c compresses the compression spring 4f in the cylinder 4g. Since it raises, the workpiece | work 5 can be pressed and positioned on the workpiece | work 7 with the repulsive force of the compression spring 4f.

  Therefore, the workpiece positioning method and workpiece mounting method of this embodiment can provide the same effects as the workpiece positioning method and workpiece mounting method of the previous embodiment, and further the workpiece positioning method and workpiece mounting method of this embodiment. According to the above, even if the work 5 is, for example, a plastic plate that is not attracted by the permanent magnet 4e, the work 5 can be positioned and mounted by being held by the holding jig 4.

  FIG. 7 is a cross-sectional view showing still another embodiment of a work mounting method using an articulated robot according to the present invention using still another embodiment of a work positioning method using an articulated robot according to the present invention. The workpiece positioning method and workpiece mounting method of this embodiment are different only in that the holding jig 4 has an enlarged collet chuck 4l instead of the permanent magnet 4e and the suction pad 4j. Since this embodiment is the same as that of the embodiment, the differences will be mainly described here.

  That is, the holding jig 4 in the workpiece positioning method and the workpiece mounting method of this embodiment includes a bracket 4a having a base fixed to the tool changer 3 and extending in a plane parallel to the arm 1, and a tip portion of the bracket 4a. The cylinder 4g is provided so as to extend orthogonally to the bracket 4a, the normal diameter collet chuck 4l mounted downward on the lower end of the cylinder 4g, and the cylinder 4g can be moved up and down in an airtight manner. The piston 4n is connected to an operating rod 4m that expands and contracts the tip of the expanded collet chuck 4l and moves the operating rod 4m up and down.

  Here, the distal end portion of the expanded collet chuck 4l has an outer diameter that can be loosely inserted into the through hole 5a of the workpiece 5 when the diameter is reduced, while the outer diameter fits tightly within the through hole 5a when the diameter is increased. It becomes.

  Therefore, the workpiece positioning method and workpiece mounting method of this embodiment can provide the same effects as the workpiece positioning method and workpiece mounting method of the previous embodiment, and further the workpiece positioning method and workpiece mounting method of this embodiment. Even if the work 5 is not attracted by the permanent magnet 4e, for example, a plastic plate or the like, it can be positioned and mounted by being held by the holding jig 4, and the diameter of the through hole 5a is increased even if there is some variation. The workpiece 5 can be securely held by inserting the tip of the mold collet chuck 4l.

  Although the present invention has been described based on the illustrated examples, the present invention is not limited to the above-described examples, and can be appropriately changed within the scope of the claims. For example, the work positioning method of the above-described embodiments In this case, the multi-joint robot is a double-arm robot, but the multi-joint robot may be a single-arm robot. In this case, the workpiece is moved to a specific position of another workpiece by a tool that is moved by another multi-joint robot or a dedicated machine. It may be attached to.

  In the workpiece positioning method and workpiece mounting method of the above embodiment, the electric driver is used as the tool as the hand of the other arm. However, an air driver, a welding gun, an adhesive discharge device, or the like may be used. In the workpiece positioning method and workpiece mounting method of the above embodiment, the workpiece is a plate, but it may be a block and the reference portion is a round hole. In this case, the holding jig 4 may hold the workpiece using a reduced diameter collet chuck.

  Thus, according to the workpiece positioning method by the articulated robot of the present invention, a simple jig and a simple operation of the robot can be performed without strictly measuring the position and posture of the workpiece placed at random positions and postures. Thus, the workpiece can be positioned at a predetermined position and posture with efficient control.

  According to the work mounting method using an articulated robot according to the present invention, it is possible to cause a double-arm robot to reliably perform a work of mounting a work placed at a random position and posture on another work.

1, 2 Arms 3 Tool changer
4 Holding jig 4a Bracket 4b Support cylinder 4c Support shaft 4d Positioning pin 4e Permanent magnet 4f Compression spring 4g Cylinder 4h Piping 4i Engagement screw 4j Adsorption pad 4k Annular gasket 4l Expanded collet chuck 4m Actuating rod 4n Piston 5, 7 Work 5a , 5b Through-hole 6 Contact jig 8 Electric screwdriver 9 Screw T Work table

Claims (4)

When picking up a workpiece placed at a random position and posture with the hand of an articulated robot and positioning it at a predetermined position and posture,
A predetermined part of the workpiece is set as a reference portion in advance, a holding jig is provided as the hand to hold the workpiece so as to be rotatable around the axis of the reference portion, and is further set at a predetermined position with respect to the robot. A dimension-shaped contact jig is provided,
First, the work is held by the holding jig so as to be rotatable around the axis of the reference portion,
Next, the holding jig is moved while the work is brought into contact with the contact jig, and the work is rotated around the axis of the reference portion until a predetermined posture is obtained.
Next, the work positioning method using an articulated robot, wherein the holding jig is moved to place the work at a predetermined position.   The work positioning method using an articulated robot according to claim 1, wherein the reference portion is a round hole formed in a predetermined part of the work.   3. The work positioning method using an articulated robot according to claim 1, wherein the holding jig holds the work in a state where a positioning member is fitted to a reference portion of the work. . The articulated robot is a double-arm robot;
The double-arm robot uses the holding jig as a hand of one arm to position the work by the work positioning method according to any one of claims 1 to 3, while using a tool as a hand of the other arm. A work mounting method using an articulated robot, wherein the work is mounted and fixed to another work.

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