JPH0145385B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position detection method for positioning a ball such as a tennis ball having a dumbbell-shaped seam line on its surface as shown in FIG. 2 in a manufacturing process or an inspection process.

Generally, the manufacturing process of balls such as tennis balls,
In the inspection process, it is absolutely necessary to position the ball in a fixed position when measuring stamp marks and compression. That is, the stamp is placed on the waist of the dumbbell ball as shown in Figure 1a, and the compression must be measured at the hip area as shown in Figure 1b or the waist area as shown in Figure 1c according to the JTA standard. . The automatic positioning of the ball for this purpose has conventionally been investigated using an image sensor method, but this method does not clearly capture the seam on the ball surface, is very time consuming, and is expensive. It was impossible to implement due to problems such as high cost. For this reason, we currently rely on manual labor, but the work requires high positioning accuracy and is highly repetitive, placing a heavy burden on the workers, making it impossible to work continuously for long periods of time, and positioning due to fatigue. The decrease in accuracy cannot be ignored either. Moreover, this also placed a limit on the improvement of processing capacity. Except for this positioning work, the equipment for the previous and subsequent processes is automated, so if it becomes possible to automatically position the ball, it will be possible to fully automate stamp marks and compression measurements, which could lead to human error caused by simple work. This will greatly contribute to labor savings and cost reductions.

The present invention provides a means to solve these conventional problems. It detects the attitude (orientation) of the ball, makes it possible to automate positioning, and eliminates positioning errors caused by individual differences to achieve high precision. It is an object of the present invention to provide a method for detecting the position of a ball, which can be applied to positioning, etc.

Hereinafter, the present invention will be explained in detail based on the drawings.

First, to explain the principle of the present invention using a tennis ball as an example, the surface of the tennis ball is formed by bonding two melton dumbbells 1, 1 of the same shape as shown in FIGS. 2 and 3. , the pasted part is called a seam, and since it appears in a linear shape, the line is called a seam line. Each dumbbell 1 has two hip parts 2, 2 which are arc-shaped parts on both sides, and one waist part 3 in the middle part.
It consists of Here, assuming that the center points of the hip portions 2, 2 are A1, A2, and the center of the waist portion 3, that is, the midpoint between the center points A1, A2 is B, the dumbbell 1 has the following properties.

(a) Each hip part 2, 2 of the dumbbell 1 forms a part of a circle with a radius of R, and its center is at the center point A above.
1, matches A2.

(b) The center of the circle is on the perpendicular bisector M′ of the chord L′.
That is, the positions at a radius R inward from the point where the perpendicular bisector M' of the chord L' intersects with the circular arc portion of the hip portion 2 are the center points A1 and A2 of the circle.

(c) If the center axis A1-A2 connecting the center point A1 and center point A2 of either dumbbell 1 is considered as the rotation axis, then the midpoint B between both dumbbells 1, 1,
Both points B are on the equator (see Figure 6).

The positions of points A1, A2, and B can be determined using the properties of (a), (b), and (c) above. In FIG. 4, when the ball 4 rotates around an axis X passing through its center, the trajectory K of the intersection of the axis Z perpendicular to the axis X and passing through the center of the ball 4 and the surface of the ball 4
intersects with the dumbbell seam line 5 at several places. The number of intersections P is limited to three types: 2, 3, and 4. Therefore, when expanded, the trajectory K when there are four intersection points P becomes as shown in Fig. 5,
The part where the length between two adjacent intersection points is the shortest (in the example shown, between P1 and P2) is always the chord L'. That is, the intersection points P1 and P2 of one dumbbell 1 are always in a part of the circle forming the hip part 2, and the other intersection points are not necessarily in a part of the circle forming the hip part 2. For example, in the case of point P4 of one dumbbell 1,
The line segment between the P4 point and the P3 point does not form a chord because the P4 point is not in a part of the circle. Therefore, the shortest locus in FIG. 4, that is, the arc L, corresponds to the chord L', and the perpendicular bisector M' of this chord L' (the arc L in FIG.
If the ball 4 is rotated by a radius R from the seam line 5 (the intersection G of the arc of the hip part 2 and the perpendicular bisector M') in the direction corresponding to the imaginary perpendicular bisector m of the chord l, , center points A1, A2 can be determined. In addition,
The midpoint N of the chord L' corresponds to the center n of the arc L in FIG.

Next, as shown in FIG. 6, the pair of center points A1 and A2 in one dumbbell 1 are opposite to each other, and due to the property (c) above, the center point A1 and the center point A
The center axis A1-A2 connecting 2 is the rotation axis, and the intermediate points B and B are on the equator, but the longer arc length on the equator between the two intersections Q and Q between the equator and the seam line 5 Alternatively, by taking the midpoint of the shorter one, the positions of midpoints B and B can be determined.

Based on the above principle, dumbbell 1 at ball 4
It becomes possible to detect the position of the center points A1, A2 of the hip part 2 or the midpoint B of the waist part 3. In particular, as described above, the most important point is to find the rotation axis of the ball 4 where the number of intersections P between the dumbbell seam line 5 and the trajectory K is four.

Next, a first invention based on the above-mentioned principle will be explained using FIG. 7 showing one embodiment thereof. In the following explanation, the same reference numerals will be used for parts corresponding to the explanation of the principle described above.

In FIG. 7, the ball 4 has an origin O at the intersection of three mutually orthogonal axes X, Y, and Z.
The ball 4 is fixedly supported by a support device (not shown) so that the center point of the ball 4 coincides with the center point of the ball 4 . Note that it is best to use a robot as the support device from the viewpoint of ease of positioning after the position of the ball 4 is detected. On the other hand, the sensor 6 for detecting the seam line 5 is freely rotatable around the ball 4 by a rotary drive device (not shown), centered around the origin O, and with its axis passing through the origin O. The rotation is controlled by a rotation degree detection device and a device capable of being driven by degrees in the drive device. As this sensor 6, for example, as shown in FIG.
A reflective optical sensor 9 having a light receiving section 8 is used. That is, the light is projected onto the surface of the ball 4 while rotating, and the part of the Melton dumbbell 1 and the seam line 5 are
The amount of reflected light from the part is detected and an output signal is generated based on the difference. If such an optical sensor 9 is used, the seam line 5 can be detected reliably. This output signal is sent to a control section (not shown), and the rotary drive device is automatically controlled based on this output signal. In addition, in order to improve the positioning accuracy, it is preferable that the position where the output is output as the seam line 5 detection is set at the center of the seam line 5 by dividing the width S of the seam line 5 into two. Further, the control section stores various data such as the number of rotations during each axis processing cycle. With the above-described device, the sensor 6 is rotated around the ball 4 set in an arbitrary direction to search for dumbbell-shaped seam lines 5 on the surface, and the distance (rotation angle) between the seam lines 5, The rotation of the sensor 6 is controlled by storing the number of intersection points P and processing this data, and the sensor is placed at the center points A1, A2 of the hip parts (circular parts on both sides) 2, 2 and the midpoint B of the waist part 3. 6 can be made to correspond.

Hereinafter, the center point A1 of the hip portion 2 using the sensor 6,
A method for detecting A2 will be explained with reference to the flowchart shown in FIG.

First, the sensor 6 is fixed relative to the three axes X,
Axis X or Y or Z that rotates around Y and Z respectively, and detection of seam line 5 in one rotation produces four outputs.
seek. In FIG. 7, four outputs are obtained in rotation around the axis X. Next, move the sensor 6 to the axis
Rotating around the center n of the shortest arc L between the outputs
Align the axis of sensor 6 with . FIG. 7 shows this state. Next, the sensor 6 is rotated so that the locus of the axis of the sensor 6 on the surface of the ball 4 coincides with the direction of the virtual perpendicular bisector m of the chord l of the arc L (in the example shown, it is rotated around the axis Y). ). In other words,
In Figure 5, the above locus is the perpendicular bisector of the chord L'
Corresponds to M′. Then, the seam line 5 to be used as a reference in this rotation around the axis Y is detected. That is, the reference seam line 5 exists at two locations, one at a short distance from the center n within the radius R in FIG. 2, and the other at a far distance from the center n in the same direction.

First, in the case of detecting the seam line 5 located at a short distance, the sensor 6 only needs to be rotated by a small angle. However, if no output is produced even after rotating by more than a predetermined center angle corresponding to approximately the radius R, the rotation should be performed in the opposite direction. . Thereafter, by rotating the sensor 6 in the opposite direction around the same axis Y by the center angle of the ball 4 corresponding to the radius R from the detection position, the sensor 6 can be positioned at the center point A1 or A2 of the hip portion 2. . In addition,
If no output is produced even after rotating the sensor 6 by the central angle equivalent to the radius R, as described above, do not rotate the sensor 6 in the opposite direction, but instead rotate it nearly one full rotation (360 degrees) in the same direction to achieve the desired purpose. The seam line 5 is detected at a position a short distance away from the seam line 5, and then the sensor 6 is moved to the ball 4 corresponding to the radius R from the detected position.
A method of rotating in the same direction by the central angle of is also possible. In this way, the load on the device due to reverse rotation is eliminated, and the detection time can also be shortened.

Next, in the case of detecting a seam line 5 located at a far distance from the center n, the sensor 6 will detect two seam lines 5. First, the seam line 5 at a short distance is detected in the same manner as described above, and then the sensor 6 is rotated in the same direction, and the seam line detected first is determined as the target seam line 5 at a long distance. Then, if the sensor 6 is rotated in the same direction from this position by the center angle of the ball 4 corresponding to the radius R, the center point A1 or A of the hip portion 2 is rotated.
The sensor 6 can be positioned (corresponding) to two positions.

Next, a second invention will be described in which, like the first invention, the sensor 6 is rotated and the ball 4 is fixed, and the position of the sensor 6 is made to match the midpoint B of the waist portion 3. FIG. 10 shows a schematic perspective view of a cylinder of one embodiment, and FIG. 11 shows a flowchart, but the apparatus is exactly the same as the first invention, and the detection method is such that the sensor 6 is connected to the hip part 2.
The steps up to positioning the center point A1 or A2 are the same, so the explanation up to that point will be omitted.

That is, the sensor 6 is positioned at the center point A1 or A2 of the hip part 2 through the same steps as in the first invention, and then the sensor 6 is positioned at a 90 degree angle from this position to the axis passing through the center points A1 and A2. Rotate the sensor 6 by 90 degrees around the axis. This allows sensor 6
is located on the equator where intermediate points B and B exist. Therefore, this time, the seam line 5 is detected by rotating in a direction perpendicular to the rotation direction, that is, along the equator. Then, the sensor 6 can be positioned at the midpoint B in the waist portion 3 by rotating from the seam line 5 in each direction by half the rotation angle of the longer or shorter length between the seam lines 5. can.

Furthermore, in the case where the sensor 6 rotates and the ball 4 is fixed, a third invention will be described in which the sensor 6 position is made to coincide with the intermediate point B in the waist portion 3 similarly to the second invention. In this invention, a second sensor 10 is particularly provided as shown in FIG. This second sensor 10 is always located on a virtual plane that includes the origin O and is perpendicular to the sensor 6, and rotates around the ball 4 on the virtual plane with the origin O as the center. That is, both sensors 6 and 10 are in a fixed relative relationship of 90 degrees to each other.
Note that as the second sensor 10, a reflective optical sensor 9 is used like the sensor 6.

Therefore, to explain the position detection method, as shown in the flowchart of FIG.
1 or A2 (description of the previous steps will be omitted). In that state, the second sensor 10 is on the equator where the intermediate points B and B exist, and then the second sensor 10 is rotated around the ball 4 on the equator along the virtual plane, and the second sensor 10 is rotated around the ball 4 on the equator along the virtual plane. The seam line 5 is detected by the second sensor 10. Then, by rotating the second sensor 10 in the respective directions from the seam line 5 by half the rotation angle of the longer or shorter length between the seam lines 5, the intermediate point B of the waist portion 3 is detected. second sensor 1
The axis T of 0 can be made to coincide with each other.

In this way, by using the second sensor 10 exclusively for detecting the intermediate point B, the rotation of the sensor 6 by 90 degrees after positioning the sensor 6 in the second invention to face the center point A1 or A2 is omitted. It is possible to reduce the number of steps by one step.

As explained above, in the first, second, and third inventions, the sensor 6 or 10 detects the center point A1,
A2 or intermediate point B can be detected, and this center point A1,
The position of A2 or intermediate point B is known. Therefore, if the ball 4 is supported by a robot, subsequent positioning of the ball 4 can be easily performed by inputting this position data. Furthermore, if the sensors 6 and 10 are attached to the tip of the arm of the robot and the robot controls its rotation, the robot can always grip the ball 4 in a fixed position, allowing the robot to carry out the next process (inspection and various processing).
The work efficiency can be further improved.

In addition, as a method for verifying (checking) the positional deviation of the ball 4 detected in this way, three sensors 11 are placed on the same curved shape as the seam line 5 as shown in FIG. established,
There is a method in which the sensors 11... and the seam line 5 are superimposed, and if all three sensors detect the seam line, it is determined that there is no deviation, and the axis Z as shown in FIG.
A possible method is to rotate a single sensor 11 provided at a position that coincides with the arcuate portion 2 of the seam line 5 around the axis Z to see the seam line detection angle of the ball 4. That is, the latter method is a method in which the sensor 11 is rotated around the axis Z by a drive device with a built-in rotation degree detection mechanism, and if the rotation degree at which the seam line is detected is a predetermined value or more, it is determined that there is no deviation. be.

FIG. 16 is a simplified plan view of an inspection device equipped with a position detecting section 17 based on the position detecting method of the present invention. In this figure, the testing device for the compression test of the balls 4 consists of an input section 13, a position detection section 17, a positioning section 12, a verification section 14, a compression measurement section 15, and an ejection section 16. The posture (orientation) of the ball 4 thrown in from the throwing part 13 is detected by the position detection part 17 using the above method, then it is positioned in the positioning part 12, and then in the verification part 14 (see FIG. 14 or 15). As described above), a check for positional deviation is performed, and the correctly positioned balls 4 are sent to the compression measuring section 15 in the next step, where a predetermined operation is performed. Thereafter, the balls 4 are sent out from the discharge section 16 toward the next work process. In this way, it is possible to fully automate a series of inspection work processes, which has great effects.

In the first to third inventions described above, the tennis ball 4 is used as an example, but other than tennis balls may also be used, such as dumbbells 1 and 1, which have the same shape and whose both ends are part of a circle. The present invention can be applied to any spherical object that is to be bonded (including objects other than bonding) by detecting seam lines on the surface (and objects corresponding thereto).

The present invention has effectively achieved its intended purpose with the configuration detailed above. In particular, the sensors 6 and 10 are rotated around the ball 4, the dumbbell-shaped seam line 5 on the surface of the ball 4 is detected by the sensors 6 and 10, and the sensors 6 and 10 are connected to the hips of the seam line 5 (the arc-shaped portions on both sides). ) 2, or at the midpoint B of the waist portion 3, the detection accuracy is good and the detection speed is fast. Especially from this state, the ball 4 can be positioned with high precision, and the positioning Achieved automation. It is possible to eliminate positioning errors that occur in the past due to individual differences among workers. Even if some error occurs, it depends on the accuracy of the device, and the degree of error is almost uniform, so large variations between workers or among the same worker can be prevented. This eliminates worker fatigue, which greatly affects manual positioning accuracy.
Can work continuously. Furthermore, by automating the positioning work based on the present invention, a series of manufacturing processes such as stamp marks and compression measurements, and inspection processes can be completely automated, making it possible to significantly reduce costs by reducing the number of personnel.

[Brief explanation of drawings]

Figure 1 is a plan view of the ball showing the stamp position and compression measurement position, Figure 2 is a developed plan view of Melton dumbbells to explain the principle of the invention, and Figure 3 is the position of two Melton dumbbells. FIG. 4 is a perspective view of a tennis ball to explain the principle of positioning; FIG. 5 is a developed plan view of the Melton dumbbell in FIG. 4;
FIG. 6 is a front view of a tennis ball for explaining the principle, FIG. 7 is a simplified perspective view showing an embodiment of the first invention, FIG. 8 is a side view of the optical sensor, and FIG. 9 is a diagram of the first embodiment. A flowchart of the invention, FIG. 10 is a simplified perspective view showing an embodiment of the second invention, FIG. 11 is a flowchart of the same, and FIG. 12 is a simplified perspective view showing an embodiment of the third invention. FIG. 13 is a flowchart of the same, FIGS. 14 and 15 are simplified diagrams for explaining the verification method after positioning, and FIG. 16 is a simplified plan view of an example of an inspection apparatus to which the method of the present invention is applied. 2...hip part (arc shaped part), 4... ball, 5...
Dumbbell-shaped seam line, 6...sensor, 10...
Second sensor, X, Y, Z...axis, O...origin, A
1, A2...Center point, B...Intermediate point, L...Circular arc, l...
Chord, R...radius, m...perpendicular bisector, n...center.

Claims (1)

[Scope of Claims] 1. The intersection of three axes X, Y, and Z that are orthogonal to each other is set as an origin O, and the ball 4 is supported in a fixed state so that the center point of the ball 4 coincides with the origin O, and the ball 4 is supported in a fixed state. A sensor 6 is provided that rotates around the ball 4 with the origin O as the center and the axis passes through the origin O, and detects the dumbbell-shaped seam line 5 on the surface of the ball 4. ,Z
The sensor 6 is rotated around the axis to find the axis where the detection of the seam line 5 in one rotation produces four outputs, and then the sensor 6 is rotated around the axis and the sensor is placed at the center n of the shortest arc L between the outputs. Align the axes of 6,
Next, the sensor 6 is rotated so that the locus of the axis of the sensor 6 on the surface of the ball 4 coincides with the direction of the virtual perpendicular bisector m of the chord l of the arc L, and the seam line to be used as a reference is Then, from the detected position, the sensor 6 is moved by the center angle of the ball 4 corresponding to the radius R of the arcuate portions 2, 2 on both sides of the seam line 5.
in the opposite direction or in the same direction, and then the sensor 6 position is adjusted to the center point A1, A of the both side arcuate portions 2, 2.
2. A ball position detection method characterized by matching the position of a ball. 2 The intersection of the three mutually orthogonal axes A sensor 6 is provided that rotates around the ball 4 so that its axis passes through the origin O, and detects a dumbbell-shaped seam line 5 on the surface of the ball 4.
The sensor 6 is rotated around the axis to find the axis where the detection of the seam line 5 in one rotation produces four outputs, and then the sensor 6 is rotated around the axis and the sensor is placed at the center n of the shortest arc L between the outputs. Align the axes of 6,
Next, the sensor 6 is rotated so that the locus of the axis of the sensor 6 on the surface of the ball 4 coincides with the direction of the virtual perpendicular bisector m of the chord l of the arc L, and the seam line to be used as a reference is Then, from the detected position, the sensor 6 is moved by the center angle of the ball 4 corresponding to the radius R of the arcuate portions 2, 2 on both sides of the seam line 5.
rotate in the opposite direction or in the same direction to align the sensor 6 position with the center points A1, A2 of the both side arcuate parts 2, 2, and then rotate the sensor 6 from this position by 90 degrees.
The ball is characterized in that after being rotated once, the ball is further rotated in an orthogonal direction to determine the midpoints B, B of the seam line 5 in the rotational direction, thereby aligning the position of the sensor 6 with the midpoints B, B. position detection method. 3. Support the ball 4 in a fixed state so that the center point of the ball 4 coincides with the origin O at the intersection of the three mutually perpendicular axes A sensor 6 is provided that rotates around the ball 4 so that its axis passes through the origin O, and detects a dumbbell-shaped seam line 5 on the surface of the ball 4.
Rotate the sensor 6 around the axis to find the axis for which the detection of the seam line 5 in one rotation produces four outputs, then rotate the sensor 6 around the axis and align the sensor 6 with the center n of the shortest arc L between the outputs. Align the axes of 6,
Next, the sensor 6 is rotated so that the locus of the axis of the sensor 6 on the surface of the ball 4 coincides with the direction of the virtual perpendicular bisector m of the chord l of the arc L, and the seam line to be used as a reference is Then, from the detected position, the sensor 6 is moved by the center angle of the ball 4 corresponding to the radius R of the arcuate portions 2, 2 on both sides of the seam line 5.
in the opposite direction or in the same direction to align the sensor 6 position with the center points A1, A2 of the both side arcuate parts 2, 2, and in that state, the sensor 6 position including the origin O and the axis of the sensor 6. The second sensor 10 on an imaginary plane that is perpendicular to the imaginary plane is rotated around the ball 4 along the imaginary plane to find the midpoint B, B of the seam line 5 in the rotational direction, and then A method for detecting the position of a ball, characterized in that the position of the sensor 10 is made to coincide with the intermediate points B, B.