JPH05228780A - Teaching method of gripping position for objecting work to be gripped - Google Patents

Abstract

PURPOSE:To surely grip the outer diameter of a work without interfering with the other work by teaching the gripping position of an objective work to be gripped in the condition of adding the occupied space of a gripping member to the external form of the objective work to be gripped. CONSTITUTION:When a gripping position is teached so as to grip the outer circumferential decided position of an objective work 7 to be gripped with a gripping member, the gripping position of the objective work is teached in the condition of adding the occupied space 7a of the gripping member to the external form of the objective work 7 to be gripped. Hereby, according to adding the occupied space 7a, it can be recognized that the outer diameter of the work 7 can be gripped only in case of no existence of the other work in the occupied space 7a, and the outer diameter of the work 7 can be gripped only in case of no generation of interference with the other work. In this case, the number of works 7 Judged able to be gripped is reduced, to some extent, but damage of the work, chuck, work bearing face, and the like can be previously prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gripping position teaching method for a gripping target work, and more specifically, a gripping position teaching method suitably applied when a predetermined outer peripheral position of the gripping target work is gripped by a gripping member. Regarding

[0002]

2. Description of the Related Art Conventionally, as a method for holding a work to be grasped, a vacuum suction holding method suitable for a relatively thin work, and an inner diameter suitable for a perforated work represented by a nut among relatively thick work. A gripping method and an outer diameter gripping method suitable for the remaining relatively thick work are known, and are widely adopted in the relevant fields.

Specifically, in the vacuum suction gripping method, the vacuum suction pad is lightly pressed to a predetermined position on the upper surface of a thin work, and in this state, the inside of the vacuum suction pad is negatively pressured to hold the work. In the inner diameter gripping method, a pair of chucks, which are normally in contact with each other, are inserted into a hole of a thick-walled work, and then the chucks are separated from each other to press the inner surface of the hole to grip the work. In the outer diameter gripping method,
Enclose the work with the chucks separated from each other.
After being lowered to almost the same height as the lower surface of the work, the chucks are brought close to each other to press the outer circumference of the work to grip the work.

[0004]

When the above-mentioned vacuum suction method and inner diameter gripping method are adopted, if the condition that the target work does not overlap with another work is satisfied, other work, work bearing surface, etc. It is possible to hold only the desired work without adversely affecting the. However, when the outer diameter gripping method is adopted, even if the condition that the target work does not overlap with other works is satisfied, if the chuck is lowered to grip the target work, the lower end of the chuck There is a possibility that the part may interfere with another work, and when the interference occurs, there is a disadvantage that the target work cannot be gripped. In addition, even if the lower end of the chuck interferes with other works, if the industrial robot continues the work for gripping the work, unexpected deformation occurs due to the pressing force of the chuck if the work is relatively easy to deform. There is also the inconvenience of doing. On the other hand, if the work is extremely difficult to deform, the chuck may be damaged or the work bearing surface may be damaged.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and when the outer diameter of a workpiece is grasped,
It is an object of the present invention to provide a novel gripping position teaching method that can prevent interference with other works.

[0006]

In order to achieve the above object, a method for teaching a gripping position of a gripping target work according to claim 1 teaches a gripping position so that a predetermined peripheral position of the gripping target work is gripped by a gripping member. In this case, the gripping position of the gripping target work is taught in a state where the space occupied by the gripping member is added to the outer shape of the gripping target work.

According to a second aspect of the present invention, there is provided a method for teaching a gripping position of a work to be gripped, in which the space occupied by the gripping member is determined based on the width of the gripping member in the direction orthogonal to the work contact surface. According to a third aspect of the present invention, there is provided a method for teaching a gripping position of a gripping target work, in which the space occupied by the gripping member is determined based on a circle having a predetermined radius centered on the center of gravity of the work. A gripping position teaching method of a gripping target work according to claim 4 is a method of determining an occupied space of the gripping member based on a rectangle having two sides parallel to the principal axis of inertia of the work and having a center coinciding with the center of gravity of the work. ..

[0008]

According to the method for teaching the gripping position of the gripping target work of claim 1, in teaching the gripping position to grip the predetermined outer peripheral position of the gripping target work by the gripping member, the gripping member is added to the outer shape of the gripping target work. Since the gripping position of the workpiece to be gripped is taught in consideration of the occupied space, the outer diameter gripping of the work can be performed only when there is no other work in the occupied space due to the addition of the occupied space. It can be recognized as possible, and the work can be gripped by the outer diameter only when there is no interference with other works. In this case, the number of works that can be grasped is reduced to some extent, but damage to the work, chuck, work support surface, etc. can be prevented in advance. Since the recovery work due to the damage to the workpiece is unnecessary, the work gripping efficiency can be improved as a whole. Therefore, when the invention is applied to parts removal and the like, the parts removal efficiency can be substantially improved.

According to the method for teaching the gripping position of the workpiece to be gripped according to claim 2, since the space occupied by the gripping member is determined based on the width of the gripping member in the direction orthogonal to the work contact surface, the same as in claim 1. The action of can be achieved. According to the method for teaching the gripping position of the gripping target work of claim 3, since the space occupied by the gripping member is determined based on a circle having a predetermined radius centered on the center of gravity of the work, the radius is specified by keyboard input, a cursor, or the like. The teaching work can be simplified, and the same operation as in claim 1 can be achieved.

According to the method of teaching the gripping position of the workpiece to be gripped according to claim 4, the space occupied by the gripping member is based on a rectangle having two sides parallel to the principal axis of inertia of the workpiece and having a center coinciding with the center of gravity of the workpiece. Because it is determined by
Although the teaching work becomes slightly more complicated as the number of data that needs to be set increases, the number of workpieces that are determined to be grippable can be determined because the required minimum occupied space can be taught. It can be increased and claim 1
The same action as can be achieved.

[0011]

Embodiments will now be described in detail with reference to the accompanying drawings showing embodiments. FIG. 5 is a vertical cross-sectional view schematically showing a main part of a work supply system to which the holding position teaching method of the present invention is applied. A predetermined area of a work transfer track 1 for separating and transferring the work is transparent to a predetermined area. It is replaced by a plate 2. A light source 3 for reflected light composed of a ring-shaped fluorescent lamp or the like is arranged below the light-transmitting plate 2, and a half-beam is provided between the light-transmitting plate 2 and the light source 3 for reflected light. A CCD in which a mirror 4 is arranged and receives reflected light in the range of the transparent plate 2 in a state of being reflected by the half mirror 4.
An image detection unit 5 including a camera or the like is arranged. Therefore, when the work is present on the light-transmissive plate 2, the intensity of the reflected light from the work is high and the intensity of the reflected light from the portion where the work is not present is weak, so that there is an intensity change corresponding to the work. Images can be detected. Then, based on the obtained image, binarization processing, connectivity analysis processing, feature value calculation processing, and the like are performed in an image processing unit (not shown) to identify the type, shape, and the like of the work. Incidentally, 6 is an industrial robot, 6a is a chuck, and 7 is a target work.

FIG. 1 is a flow chart for explaining an embodiment of the method for teaching the work gripping position of the present invention. In step SP1, it is judged whether or not the sample work is suitable for gripping the outer diameter, and the outer diameter gripping is carried out. If it is determined to be suitable for the step S3, the interference possible area is set based on the predetermined reference point of the work image as a reference based on the planar shape of the chuck for gripping the outer diameter in step SP2. At, the gripping position is set inside the interference possible area, and the series of processing is terminated. Conversely, step S
When it is determined in P1 that the sample work is not suitable for gripping the outer diameter, the holding position is set in step SP4, and the series of processes is ended. The flowchart of FIG. 1 is performed for each type of sample work.

FIG. 2 is a flow chart for explaining the processing in the case where the work is gripped after the gripping position is taught as described above, and the image detected by the image detection unit 5 in step SP1 is displayed. Based on this, binarization processing and connectivity analysis are performed to extract a work image, and in step SP2, a feature value is calculated based on the extracted work image, and the calculated feature value is compared with a predetermined reference value. By doing so, it is determined whether or not the work is a target work.
If it is determined that the work is not the target work, the determination in step SP2 is repeated for other work images.
On the contrary, if it is determined in step SP2 that the workpiece is the target workpiece, it is determined in step SP3 whether or not the workpiece is gripped by the outer diameter, and if it is determined that the workpiece is not gripped by the outer diameter. In step SP4, the industrial robot 6 indicates that the holding position set in the series of processes shown in FIG. 1 should be obtained to hold the target work.
Instruct. On the contrary, when it is determined in step SP3 that the workpiece is the outer diameter gripped, step SP
In step 5, a window equal to the interference possible area set in the series of processing shown in FIG. 1 is set, and in step SP6, the connectivity analysis is performed again based on the image located in the window. In step SP7, the number of images is 1 If the number of images is 1, it is determined in step SP8 that the gripping position set in the series of processes shown in FIG. 1 should be obtained to grip the target work. To an industrial robot (not shown). On the contrary, when it is determined in step SP7 that the number of images is two or more, the chuck 6a, the transparent plate 2 as the work bearing surface, and the like are damaged if the corresponding work is gripped by the outer diameter. Since there is a possibility, the determination in step SP2 is made for other work images. Although not particularly shown in the flowchart of FIG. 2, when the process for the captured image is completed, the work is conveyed for a predetermined time, for example, and then the process of the flowchart of FIG. 2 is performed again.

FIG. 3 is a diagram showing a specific example in which a circle 7a having the center of gravity of the work image as the center is adopted as the interference possible area. As shown in FIG. 3A, the target work 7 is placed inside the circle 7a. If there is only one, the chuck 6a does not interfere with other works, so that the gripping of the target work 7 can be achieved without any inconvenience. On the contrary, as shown in FIG. 3B, when not only the target work 7 but also another work exists inside the circle 7a, the chuck 6a may interfere with the other work. The target work 7 is not gripped.
In this specific example, when teaching the radius of the circle 7a, the radius may be set and input from the keyboard, but one point on the circumference may be designated by a cursor or the like, and any radius setting method may be used. Can be adopted. It is also possible to set a point other than the center of gravity, for example, the center of the work image or the like as the center of the circle 7a.

FIG. 4 is a diagram showing a specific example in which a rectangle 7b having two sides parallel to the principal axis of inertia of the work image and having a center coinciding with the center of gravity of the work image is adopted and set as the interference possible region. Since there are two kinds of power values, the work for setting the interference possible area becomes complicated as compared with the specific example of FIG. However, in the case of this specific example, it is possible to set the interference possible area as the minimum necessary area and increase the possibility that the workpiece can be determined as a workpiece that can be gripped by the outer diameter. Can be improved. Also, in the case of this specific example, the chuck 6a
It is possible to capture the reflected image in a state where the is in contact with the upper surface of the transparent plate 2 and set the interference possible area based on the captured image. In this case, the interference possible area is set. Since it is not necessary to input the numerical value, the workability for setting the interference possible region can be improved except that the industrial robot 6 has to be actually operated.

Also in this specific example, it is possible to set a point other than the center of gravity, for example, the center of the work image to the center of the rectangle 7b, and various numerical value setting input methods can be adopted. It is possible.

[0017]

As described above, the invention of claim 1 recognizes that the outer diameter of the work can be gripped only when the work space is taken into consideration and no other work exists in the work space. It is possible to hold the outer diameter of the work only when there is no interference with other works.
It has the unique effect of preventing damage to the work support surface.

According to the invention of claim 2, in addition to the effect of claim 1, the occupying space of the gripping member is determined based on the width of the gripping member which can be intuitively grasped and which can easily obtain an accurate value. Therefore, there is a unique effect that the setting of the occupied space can be simplified and the setting accuracy of the occupied space can be improved. In addition to the effect of claim 1 or claim 2, the invention of claim 3 has a unique effect that teaching work can be simplified.

According to the invention of claim 4, in addition to the effect of claim 1 or claim 2, the number of works judged to be grippable is increased due to the fact that the required minimum occupied space can be taught. It has the unique effect of being able to.

[Brief description of drawings]

FIG. 1 is a flowchart illustrating an embodiment of a method for teaching a work gripping position of the present invention.

FIG. 2 is a flowchart illustrating a process when a work is gripped after a grip position is taught.

FIG. 3 is a diagram showing a specific example in which a circle centered on the center of gravity of a work image is adopted as an interference possible area.

FIG. 4 is a diagram showing a specific example in which a rectangular shape having two sides parallel to the principal axis of inertia of the work image and having a center coinciding with the center of gravity of the work image is adopted as the interference possible region.

FIG. 5 is a longitudinal sectional view schematically showing a main part of a work supply system to which the gripping position teaching method of the present invention is applied.

[Explanation of symbols]

6a Chuck 7 Target work 7a Circle 7
b rectangle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G05B 19/42 L 9064-3H

Claims (4)

[Claims] 1. When teaching a gripping position to grip a predetermined outer peripheral position of a gripping target work (7) with a gripping member, an outer space of the gripping member (6a) is occupied by an outer shape of the gripping target work (7a). ) A gripping position teaching method for a gripping target work, which teaches the gripping position of the gripping target work (7) in consideration of (7b). 2. An occupied space (7a) for the gripping member (6a).
The method for teaching a gripping position of a gripping target work according to claim 1, wherein (7b) is determined based on a width of the gripping member (6a) in a direction orthogonal to the work contact surface. 3. A space (7a) occupied by the gripping member (6a).
Is a circle with a predetermined radius (7
The method for teaching a gripping position of a gripping target work according to claim 1 or 2, which is determined based on a). 4. A space (7b) occupied by the gripping member (6a).
The grip according to claim 1 or 2, wherein is defined based on a rectangle (7b) having two sides parallel to the principal axis of inertia of the work (7) and having a center coinciding with the center of gravity of the work (7). A method for teaching a gripping position of a target work.