JPS6034291A - Link device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention is capable of changing the posture of an image pickup device for object observation or a welding machine for object processing while always pointing at a fixed point, and the observation direction, processing direction, etc. can be changed in the coordinate system of the object. This invention relates to a link device that can be easily specified.

In recent years, industrial robots have been widely used for painting, welding, and even assembly, but many of these robots are so-called playbank robots that repeat teaching operations in advance, and are not suitable for assembly line work. Although it is suitable, it requires a large amount of expense for various jigs and teaching when applied to operations that handle many types of workpieces at the same time. For this reason, in recent years, so-called intelligent robots have been developed in which the robot itself identifies the posture of an object, searches for a necessary work surface, and specifies one position in the direction of that surface to perform the work.

By the way, in such an intelligent robot, a visual sensor is used as a means for detecting the posture of an object, especially a three-dimensional object, and an image captured by a single camera or a stereo camera is used as an input image.

However, since such images are data in the camera's coordinate system, complex calculations are required to convert them to the target object's coordinate system, and in order to capture a three-dimensional object from various angles, the camera's position and direction must be adjusted. It is necessary to determine the six degrees of freedom between the robot arm itself and the robot arm itself, which is multi-jointed and difficult to control.

The present invention has been made in view of the above circumstances, and its purpose is to provide support to each one end side and each other end of each of two link constituent members that are mutually pivotally supported with their intermediate portions intersecting. A drive source that constitutes two parallel links each having two sides, and rotates both parallel links around a link component that constitutes one of the other two sides of one of the parallel links; By providing a drive source that rotates at least one of the link constituent members constituting the biparallel link about its pivot point, it is possible to control the observation direction by an imaging device, a welding torch, a painting nozzle, etc. To provide a link device that can change the processing direction of an object, etc. while always pointing to a fixed point, and can easily specify the observation direction and processing direction using the coordinate system of the object.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof. FIG. 1 is a schematic front view showing a mode in which a link device according to the present invention (hereinafter referred to as the device of the present invention) is applied to an object shape recognition device, and FIG. 2 is an enlarged cross-sectional view taken along the line ■-■ in FIG. Figure 3 is an enlarged sectional view taken along the line ■-■ in Figure 1,
Fig. 4 is an enlarged perspective view of the image pickup unit mounting section, Fig. 5 is a partially cutaway side view of the link device main body in a folded state, Fig. 6 is a sectional view taken along line VI-VI in Fig. 5, and Fig. 7 is Enlarged front view of the image pickup unit mounting part with the link device main body folded,
FIG. 8 is also an enlarged side view, in which 1 indicates the machine frame, 2 the link device main body, 3 the imaging device, and 4 the object to be observed. The machine frame 1 is composed of channel materials (or angle materials) tied together, and a beam material 12 is passed horizontally to the upper end of four supports 11 (only two on one side are shown in the drawing). A suitable top plate 13 is placed on top of this beam 12. Approximately at the center of the top plate 13, the upper end of a vertically disposed main link component (hereinafter simply referred to as main link) 21 constituting the link device main body 2 is rotatably supported around a vertical axis (not shown). There is.

In addition to the main link 21, the link device main body 2 includes two sub-link constituent members (hereinafter simply referred to as sub-links) 22, 23.
Three link constituent members (hereinafter simply referred to as links) 24,
It is composed of 25, 26, etc., and each of these links 21
26 except for the link 26 are all made of channel material having a U-shaped cross section. Each link 21-25
As shown in FIGS. 5 and 6, the size of the concave groove, especially the inner dimension between the flanges that protrude on both sides, is the smallest for link 25, and the following links 24, 23 (equal to link 22), 21, and in the folded state, the link 25 is inside the link 24, the link 24 is inside the sub-link 22.23, and the sub-link 22.
23 are housed within the main link 21, respectively, so that the entire body is housed within the main link 21.

The secondary links 22 and 23 are of equal length and equal size, and are of the same size as the main link 2.
Located on the opening side of the groove in 1 (right side in Figure 1),
The opening of each concave groove is directed downward, and the sub link 22 is located above and below the main link 21 at approximately the center, and the sub link 23 is located at the bottom of the main link 21 with its proximal end facing downward. The horizontal shafts 22a, 22a, 23a are positioned in the grooves.
0 and link 2 which are pivotally connected to main link 21 at
4, the opening side of the concave groove is on the same side as that of the main link 21 (first
The upper end of the sub link 220 is positioned in the groove at a predetermined distance l from the base end of the sub link 220, and is pivoted to the sub link 22 using the horizontal shaft 24a. Approximately midway between the upper and lower portions, as shown in FIG. 3, a predetermined length l is inserted from the base end through the cutout portion 23b from which the web is removed, leaving flanges on both sides at the tip of the sub link 23.
, the sub link 23 is connected by the horizontal shaft 24b at a position separated by .
is pivotally connected to. Further, the link 25 has the opening of its groove on the opposite side from that of the link 24 (left side in FIG. 1).
The upper end is positioned in the concave groove at the tip of the secondary link 22, and is pivoted to the secondary link 22 using a horizontal shaft 25a at a distance l from the pivot point of the link 24. As shown in FIG. 3, the upper and lower intermediate portions are located within the cutout portion 23b at the tip of the sub link 23, and the horizontal axis is located at a distance of 1!2 from the pivot point of the link 24. It is pivotally connected to the link 23 by 25b. Thereby, the link 24 is parallel to the main link 21, and the link 25 is parallel to the link 24, and therefore also to the main link 21, but perpendicular to it.

The lower ends of the links 24 and 25 have flanges 24g, 24g, 25g, and 25g on both sides, respectively, as shown in Figure 7.8.
Cut out the web leaving 24g of each flange.

25g, 25g are split into two legs, but flange 2
The distance between 4g and 24g is 25g flange.

The image pickup device 3 is attached to the lower end portions of these flanges via links 26.

The link 26 is formed by curving a rod material into a U-shape in plan view, and both arm portions of the link 26 are removably fixed to the side wall of the image pickup device 3 with IF screws (not shown), and the horizontal via 2
Both links 2 using 6a, 26a, 26b, 26b
4.25 flange 24g, 24g.

25g, pivotally connected to 25g.

Each of these links 21 to 26 has two parallel links that share a pivot point based on the horizontal axis 24b, that is, the main link 2.
1. A parallel link composed of the sub link 22.23 and the upper half of the link 24, and a parallel link composed of the lower half of the link 24.25, the tip side of the sub link 23, and the link 26. are chained together in a pantograph shape.

Note that the upper half of the link 25 serves as a reinforcement for the link device main body 2.

The vertical shaft to which the upper end of the main link 21 is fixed is the reducer 21a
is connected to a step motor M1 via the step motor M1, and the link device main body 2 as a whole is rotated in the forward and reverse directions about the vertical axis by the forward and reverse driving of the step motor M1,
The image pickup device 3 is horizontally rotated while pointing at a fixed point 0 as shown in FIG. Further, horizontal shafts 22a, 22a that pivotally connect the base end of the sub link 22 to the main link 21 have one end thereof penetrating both flanges of the main link 21 and projecting outward, as shown in FIG. A gear 27 is fixed to one end of one shaft 22a, and a gear 27 is fixed to one end of one shaft 22a.
One end of a balancer 28 including a weight 28a is fixed to 2a so as to be in the same straight line as the sub link 22 when viewed from the front.

The gear 27 has a mounting plate 21d on the web of the main link 21.
The worm gear 29 connected to the installed step motor M2 is engaged with the worm gear 9, and the sub link 22 is moved to the horizontal shafts 22a, 22 by forward and reverse driving of the step motor M2.
It is possible to rotate the image pickup device 3 upward and downward around a, and to change its posture upward and downward within a vertical plane over approximately 100 degrees downward from the main link 21 with the image pickup device 3 pointing at the fixed point 0. It has become.

When the image pickup device 3 is in a position where its optical axis is vertical as shown by the broken line in FIG. 1, the mutual positions of the links 21 to 26 are 5th.
It is in a folded state as shown in Figures 6 and 7.8. That is, the fifth
．． As shown in FIG. 6, the link 25 is housed in the groove of the link 24, the link 24 is housed in the groove of the sub-link 22, 23, and the sub-links 22 and 23 are housed in the groove of the main link 21. As a result, the links 22 to 25 are accommodated within the main link 21. In such a folded state, in order to avoid collision between the links 24, 25 and each of the horizontal shafts 22a, 25b, etc., the horizontal shaft 22a is
The link 24 also has a horizontal axis 25b, 2
A cutout recess 24d is provided in a portion facing 3a.

24e, and the link 25 has horizontal axes 24a, 24
Notch recesses 25d and 25e in the part facing b+23a
, 25f are formed respectively.

In addition, when it is in the folded state as described above, the link 24
．． The lower end of 25 has a flange 25 as shown in Figure 7.8.
g and 25g are located between the flanges 24g and 24g, and the link 26 is located between the flanges 24g and 24g, and the image pickup device 3 is directed vertically downward toward the fixed point O. In this state, as shown in FIG. 5.7, each pivot point is positioned on the center line of rotation of the main link 21 when viewed from the front.

In addition, the link device main body 2 using step motors M, M2
The fact that the image pickup device 3 is always maintained pointing at the fixed point 0 regardless of the mutual displacement of the links 21 to 26 can be geometrically proven as follows.

9 and 10 are explanatory diagrams of the operation of the device of the present invention. As shown, the pivot points of the main link 21 and the sub link 22.23 are A, C, and the pivot points of the sub link 22.23 and the link 24. The fulcrums are B and D, and the pivot point between the sub link 23 and link 25 is E.
If the pivot points between 1 link 24.25 and link 26 are F and G, then 0ABDC.

All DDEGFs are parallelograms, and FIM'AC
It is. When the sub link 22 is rotated upward from the position shown by the broken line to the position shown by the solid line about point A, the sub link 23 is rotated about point C, and point D is moved upward from the position shown by the solid line.
It will move on the circumference of the radial surface with the point as the center.

If the intersection point on the extended line between the bean and the original is 0, then DOCDF is a parallelogram and is 2? l-1CD = OF, QC
// F'D Since there is D 75f In the process of moving on the circumference centered on point C, point P will move on the circumference centered on point 0. On the other hand, since n21m is FG/, and the extension line of the surface always passes through point C, similarly, the extension line always passes through point 0. Therefore, the optical axis of the image pickup device 3 attached to the link 26 is positioned facing the fixed point O.

By operating the link device main body 2 using the step motors M, , M, the image pickup device 3 is moved onto a spherical surface as shown in FIG. will be moved. The position of this imager 3 can be expressed in polar coordinates (r, θ, α) where r is constant, with the angle θ in the longitude direction and the angle α in the 5 degrees latitude direction centered on a point P set on the spherical surface. For example, the observation direction by the imager 3 is set to a fixed point O.
The coordinate system centered on , that is, the coordinate system of the object to be observed 4, can be specified, and the movement of the imaging device 3 to that position can be easily performed by controlling the two step motors M, , M2. When the object to be observed 4 is placed on the fixed point O, the imaging device 3 can image it from all sides except the bottom surface, and the image is stored in the image memory 11 and displayed on the monitor 12. It is also taken into the microcomputer 13 and processed.

In addition, the microcomputer 13 controls each step motor M,
, M2 to instruct the imaging position for the target object 4.

FIG. 11 is an explanatory diagram when, for example, a disk is placed as the object 4 to be observed at a fixed point 0, and the image pickup device 3 is positioned on the normal line to the surface of the disk. Assuming that the image pickup device 3 is now located at point P, drive the step motor M, and move the image pickup device 3
is horizontally rotated, and the microcomputer 13 sequentially compares the images captured by the image pickup device 3 to search for a point R where the image area is maximum, and stop the step motor M1 at that position.

Next, drive the step motor M2 to move the image pickup device 3 upward and downward perpendicular to the trajectory I)C, similarly search for the position @Q where the image area is maximum, and then
stop. This Q position is on the normal line to the center of the surface of the target object. Note that the curves Wl, Wl...wn are lines of equal area of the image of the disk object. Note that observation target object 4
Needless to say, the method is not limited to a disk, but can be applied to any shape existing on a plane, such as a character, a hole, etc.

FIG. 12 is an explanatory diagram when performing shape recognition of a three-dimensional object, for example, a tetrahedron, placed at a fixed point O. Each surface of the three-dimensional object captured by the image pickup device 3 is explained in FIG. Perform the same operation as above to position the imaging device 3 on the normal line, and judge the shape of each surface captured in that state to recognize the planar shape of each surface and judge the overall shape. becomes.

Although the above embodiment has been described with respect to a configuration in which the image pickup device 3 is attached to the link device main body 2 and applied to observation of an object, its use is not limited to this in any way; for example, it can be used in place of the image pickup device 3, or It is possible to attach a welding torch, a painting nozzle, a processing jig, etc. together with the image pickup device 3, and use it as a robot arm for welding, painting, and other processing on the surface of the spherical cylindrical part centered on the fixed point O. Of course.

These operations can be performed by changing the attitude of the imaging device 3 etc. while pointing at a fixed point O, in other words, moving on a predetermined trajectory expressed in the coordinate system of the object, so the operation itself is performed using a step motor. Since it is sufficient to control only M, , and M2, the work itself becomes extremely easy.

In the above-described embodiment, the main link 21 is fixed in a vertical state, but it can also be used with the main link 21 tilted by attaching it to the tip of a suitable boom, for example.

As described above, in the apparatus of the present invention, the observation means such as an image pickup device, or the working means such as a welding torch or painting nozzle, is always operated, regardless of the mutual displacement of the link constituent members.
It is possible to change the attitude of the object while directing it to a fixed point. In other words, it is possible to move the object on the orbital plane indicated by the coordinate system of the object placed at the fixed point, and to always keep the observation direction or working direction of the object. It is now possible to display and give instructions in a coordinate system, eliminating the need for complicated coordinate transformations.Furthermore, the observation means or processing means can be easily set in the relevant direction by controlling the two drive sources. It can be used as a robot arm, etc., and its contribution is enormous.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing a configuration in which the present invention is applied to an object shape recognition device, FIG. 2 is a partially enlarged sectional view taken along the line ■-n in FIG. 1, and FIG. 3 is a 1 in FIG. [A partially enlarged sectional view taken along the line 1-1, FIG. 4 is an enlarged perspective view of the image pickup unit mounting section, FIG. 7 is an enlarged front view of the image pickup unit mounting section when folded; FIG. 8 is a side view; FIGS. 9 and 10 are explanatory diagrams of the operation of each link component; Figures 11 and 12 are explanatory diagrams showing the movement locus of the imaging device. 1... Machine frame 2... Link device main body 3... Imaging device 4... Observation target object 21... Main link 22.
23...Sublink 24,25.26...Link
27... Worm gear 28... Balancer 29.
...Worm M, , M2...Step motor patent applicant Kenji Takahashi Patent attorney Noboru Kono 3 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 1z Figure

Claims (1)

[Claims] 1. Each one end side and each other end side of each of the two link constituent members that are mutually supported with their intermediate parts intersecting are 2.
Two parallel links are configured as sides, and a drive source and both parallel links are configured to rotate both parallel links around a link component that configures one of the other two sides of one of the parallel links. 1. A link device comprising a drive source for rotating at least one of the link components around its pivot point.