JPS6299057A - Detection of spacial position of cast product - Google Patents

Abstract

PURPOSE:To detect the spacial position certainly and easily by forming a projection part or recessed part having a prescribed form at a prescribed position and detecting the spacial position by an optical sensor, in order to detect the spacial position of a cast product for cutting an ingate, etc. CONSTITUTION:A projection part 2 having a triangular section and a height of 1-4mm is formed through casting onto the rim 1a of an aluminium wheel 1 made through casting. When the cast article is loaded onto a clamping device 5, the spacial position of a center shaft (l) is set constant for a robot device 10. An optical sensor 20 is installed onto a grinder 12, and when scanning is performed along the surface of the rim 1a, almost all the reflected light come back when the inclined surface 2a in the projection part 2 is sensed, and the received light quantity increases markedly, representing a peak. Therefore, when the projection part 2 is detected, scanning is suspended, and the spacial position of the center shaft (l) which is previously set by a controller 13 and the spacial coordinates of the projection part 2 at the stop position are obtained from the radius and the height of the projection part, and the finishing by the grinder 12 is permitted.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for detecting the spatial position of a cast product, and in particular,
The present invention relates to a method for detecting the spatial position of a cast product when removing casting holes, sprues, weir marks, etc. using a robot.

``Prior Art'' When processing a workpiece using a robot or similar automatic machine, the workpiece must be positioned accurately in accordance with teaching conditions.

However, due to variations in the shape of the workpieces, it is difficult to always position the workpieces with high precision.

Therefore, it is common practice to allow a certain amount of deviation when positioning the workpiece, use some kind of sensor to detect the position of the workpiece to determine the deviation, and use this to correct the teaching conditions set for the robot or automatic machine. It is being done.

Conventional techniques for detecting the workpiece position include, for example, the technique of detecting the workpiece position using a stylus sensor disclosed in JP-A-59-212173, and the technique disclosed in JP-A-59-212703.
A technique of detecting the three-dimensional position of a workpiece by scanning a spot hole with a beam of light disclosed in Japanese Patent Laid-Open No. 59-227382, a technique of obtaining image information and detecting the position based on the image information disclosed in Japanese Patent Application Laid-open No. 59-227382, Alternatively, there is a technique in which the workpiece is colored and the position of the workpiece is detected using a color sensor.

"Problems with the Prior Art" The conventional technology is a technique for detecting a workpiece in its original shape.

In other words, the technology on the sensor side has been improved to detect the workpiece in its original shape without making any changes to the shape of the workpiece.

However, for this reason, the sensors are generally of high quality, which not only increases the cost but also has the problem that the processing time is relatively long.

"Object of the Invention" The present invention has been made in view of the above circumstances, and its purpose is to:
It is an object of the present invention to provide a method that can reliably detect the spatial position of a cast product without using a high-grade sensor.

``Structure of the Invention'' A method for detecting the spatial position of a cast product according to the present invention is to form a convex portion or a concave portion of a predetermined shape at a predetermined location on the surface of the cast product during casting, and to detect the convex portion or the concave portion using an optical sensor. The structural feature is that the spatial coordinates of a predetermined part of the cast product are determined by detecting the cast product, and the spatial position where the cast product exists is detected based on the spatial coordinates.

The reason why the workpiece in the present invention is a cast product is because the present invention modifies the shape of the workpiece, so it is necessary to modify the shape by grinding, and such a workpiece is a cast product. It is from.

Therefore, the present invention can be applied to works other than cast products as long as the work has the above-mentioned premise.

"Operation" Unlike the conventional technique in which the shape of the workpiece is not touched, the method of the present invention forms the shape of a predetermined portion of a cast product into a shape that is easily detected optically.

Therefore, a predetermined portion of a cast product can be easily and reliably detected using an inexpensive optical sensor.

Once the position of the predetermined portion is known, the spatial position of the cast product can be calculated based on it.

The predetermined portion of the cast product is a portion that can be easily removed by subsequent machining.

Therefore, in the process leading up to the final product, a specific shape portion at a predetermined portion is cut out to give the cast product its original shape.

"Example of Actual S%" The present invention will be described in more detail below based on the examples shown in the figures. Here, Fig. 1 is a front view of the casting product and grinder finishing robot device, Fig. 2 is a side view of the same, and Fig. 3 is a front view of the casting product and grinder finishing robot device.
A flowchart of the essential parts of the operation of the grinder finishing robot shown in the figure, Figure 4+al is a sectional view for explaining the scanning of the casting surface by an optical sensor, and Figure 41bl corresponds to the scanning position shown in Figure 4+al. FIG. 5 is a plan view of the casting product shown in FIG. 1, and FIG. 6 is a cross-sectional view of the recessed portion of the present invention. Note that the present invention is not limited to the embodiments shown in the figures.

As shown in Fig. 1, Fig. 2, Fig. 4+al and Fig. 5, the cast product is an aluminum wheel l, and a triangular cross section (in the circumferential direction of the rim 1. A convex portion 2 is formed with a cross section taken along the line.

This convex portion 2 is formed at the same time as the aluminum wheel 1 is cast.

The aluminum wheel 1 is a grinder finishing robot device 1
It is placed on a clamping device 5 installed at a predetermined position relative to 0.

Therefore, the spatial position of the central axis l of the aluminum wheel 1 is defined by the clamp device 5 and remains constant.

However, since the rotation around the central axis l is not regulated, it is unclear in what rotational position the aluminum wheel 1 is placed on the clamp device 5.

Therefore, the present invention is applicable to detect the rotational position of the aluminum wheel 1.

The grinder finishing robot device 10 has an X axis.

An orthogonal coordinate robot 11 having three movement axes, a Y-axis and a Z-axis, a grinder 12 attached to its wrist, and a control device 1 containing a computer that controls these.
It basically consists of 3.

An optical sensor 20 is attached to the grinder 12 . The optical sensor 20 is a reflective distance sensor that includes a light projector and a light receiver, and its output signal is monitored by the control device 13. Note that a reflective photoelectric switch may be used instead of this.

Rim 1 of aluminum wheel 1. The surface of is subjected to a grinder finish by the grinder finishing robot device 10 described above.

The convex portion 2 is formed on the surface to be finished with a grinder. This is because it is easily cut off during finishing with a grinder. The height of the convex portion 2 is set to a level that can be easily removed later, and is, for example, about lfi to 4 cranes. Slope 2. Although the inclination angle β of the optical sensor 20 depends on the performance of the optical sensor 20, it is, for example, 15° to 50". The length of the inclined surface 21 depends on the size of the sensing spot of the optical sensor 20. It is about 8 cranes.

The optical sensor 20 is installed at an angle directly facing the inclined surface 21 of the convex portion 2 . In other words, the rim 11 is inclined by α from the direction perpendicular to the surface;
is made approximately equal to the above-mentioned β.

The distance jllL between the optical sensor 20 and the inclined surface 21 depends on the performance such as the detection distance of the optical sensor 20, but is, for example, 30 f.
It is about 40 dragons.

When the optical sensor 20 is scanned along the surface of the rim la as shown by the arrow ta+ in FIG.
．． When sensing the original surface of the object, almost no reflected light returns, so the amount of light received is small.

However, the sensor 20 is located on the inclined surface 2. of the convex portion 2. When sensing, most of the reflected light returns, so the amount of light received becomes significantly larger.

Therefore, the output voltage of the optical sensor 20 shows a steep peak only at the position where the optical sensor 20 senses the convex portion 2, as shown in FIG. 4fb, for example.

Therefore, even if a simple-configured optical sensor 20 is used, the convex portion 2 can be easily detected, and a simple process for monitoring by the control device 13 is sufficient.

Now, FIG. 3 shows the operating procedure of the grinder finishing robot device 10.

First, in teaching the grinding work for the aluminum wheel 1, the flowchart shown on the left side of FIG. 3 is followed.

That is, the radius R and height H of the aluminum wheel 1 are
It is input to the control device 13 (31).

Then, the control value ff13 performs "reference point automatic detection processing" (32).

As shown in the center of Fig. 3, this "reference point automatic detection process" is based on the preset spatial position of the central axis l of the aluminum wheel l and the radius R and height H input above. , calculate the spatial position of the surface of the rim 11, move the optical sensor 20 along the surface at a constant speed, and monitor the output voltage V of the optical sensor 20 during that time (Sll).
.

Then, the control device 13 focuses on the change ΔV in the output voltage V of the optical sensor 20, and the change ΔV exceeds the preset upper limit value Δv0 at a number of control cycles that is less than or equal to the preset number of control cycles. Then, it is determined that a steep peak has appeared, and scanning is stopped (S12).

Next, the control device 13 reads the coordinate values at the stop position, determines the spatial coordinates where the convex portion 2 exists, that is, the position of the reference point based on the coordinate values, and further calculates the spatial coordinates of the reference point and the known central axis of the aluminum foil. A certain angle θ of the convex portion 2 is derived based on the spatial position of shall be taken as the reference position.

When the "reference point automatic detection process" at the time of teaching is completed, the angle θ obtained there is stored as θ (S3).

Since the teaching angle θ of the aluminum wheel l has been obtained above, the operator performs the prescribed teaching (S4)
.

During playback, as shown on the right side of FIG. 3, "automatic reference point detection processing" is first performed to detect the rotational position of the aluminum wheel 1 placed as a workpiece (S21).

This "reference point automatic detection process" is the process described above, and a certain angle θ of the reference point is obtained.

If the angle θ is obtained by the “reference point automatic detection process” during playback, the angle θ is stored as θr (S22).

If the angle θt is equal to the angle θt at the time of teaching, the position data given by the teaching is used as is to proceed with the predetermined work.

However, when the angle θ is different from the teaching angle θ1,
Since the angle of the aluminum wheel 1 at the time of teaching is different from the angle of the aluminum wheel l at the time of reproduction, a process is required to correct the taught position data. Therefore, the following calculation is performed to convert the taught position data in accordance with the angle of the aluminum wheel 1 at the time of reproduction (S23).

This calculation can be performed by θJ=θ1−θr...■, where the taught position is (''+, Vt) and the corresponding position during reproduction is (!r, yr).

Thus, if OIr, Yr) is obtained, then (x+, y,
) can be moved to (Xr, yp) to perform the desired playback operation (S24).

Since the protrusions 2 are easily removed at the same time as or after the above-mentioned regeneration, the formation of the protrusions 2 does not affect the finished product at all.

FIG. 6 shows an embodiment in which a concave portion 32 is provided in place of the convex portion 2. As shown in FIG.

That is, the spatial position of the cast product 30 can be detected by forming the recess 32 within the cutting margin 31 on the surface of the cast product 30 and detecting the position of the recess 32.

Since the recessed portion 32 is formed within the range of the cutting margin 31, when the portion of the cutting margin 31 is removed by finishing machining, no effect of the formation of the recessed portion 32 remains.

Similarly to the convex portion 2, the concave portion 32 is preferably provided with a surface inclined with respect to the original surface of the cast product 30 in order to facilitate detection.

As is clear from the above explanation (particularly from Fig. 4 (output signal diagram of BL)), by forming a convex or concave portion on the surface of a cast product, its position can be reliably detected using a simple optical sensor. Therefore, the device configuration can be simplified.

"Effects of the Invention" According to the present invention, when casting a cast product, a convex part or a concave part of a predetermined shape is formed in a predetermined part of the surface of the product, and the convex part or the concave part is detected by an optical sensor. A method for detecting the spatial position of a cast product is provided, which is characterized by determining the spatial coordinates of a predetermined part of the product and detecting the spatial position of the cast product based on the spatial coordinates. Since the part or recess is detected, the detection can be performed more reliably and easily even with a simple optical sensor than in the case of detecting the shape of the cast product itself.

Therefore, the configuration for detecting the position of the cast product can be simplified. Furthermore, processing efficiency for detection can be improved.

Furthermore, the convex portions or concave portions of the present invention are excellent in reliability because they do not disappear or adhere to others like marks made by paint.

Furthermore, since the convex portions or concave portions according to the present invention can be easily removed by grinding the cast product, there is an advantage that they do not affect the shape of the final product in any way.

[Brief explanation of drawings]

FIG. 1 is a front view of a cast product and a grinder finishing robot device, FIG. 2 is a side view of the same, and FIG. 3 is a flowchart of the main parts of the operation of the grinder finishing robot device shown in FIG.
FIG. 4 (5) is a cross-sectional view for explaining scanning of the casting surface by the optical sensor, FIG. 4 (bl is an output signal diagram of the optical sensor corresponding to the scanning position shown in FIG. 4 (a), Fifth
This figure is a plan view of the cast product shown in FIG. 1, and FIG. 6 is a cross-sectional view of a recessed part according to the present invention. (Explanation of symbols) l... Aluminum wheel 11... Rim 2... Convex portion 5... Clamp device 10... Grinder finishing robot device 20... Optical sensor
2. ... Inclined surface 32 ... Concave portion 31 ...
・Remove it.

Claims (1)

[Claims] 1. (a) When casting a cast product, a protrusion or depression of a predetermined shape is formed at a predetermined location on the surface of the product, and (b) the protrusion or depression is detected by an optical sensor. A method for detecting the spatial position of a cast product, comprising: (c) determining the spatial coordinates of a predetermined part of the cast product; and (c) detecting the spatial position where the cast product exists based on the spatial coordinates. 2. The method for detecting the spatial position of a cast product according to claim 1, wherein the convex portion or the concave portion is provided in a cutting margin of the cast product and is removed by grinding. 3. The method for detecting the spatial position of a cast product according to claim 1 or 2, wherein the convex portion or the concave portion has a shape having a surface inclined with respect to the surface of the cast product in the vicinity thereof. 4. The method for detecting the spatial position of a cast product according to claim 3, wherein the inclined surface has an inclination angle of 15° to 50°. 5. The method for detecting the spatial position of a cast product according to claim 1, 2, 3, or 4, wherein the convex portion or the concave portion has a triangular cross section. 6. The method for detecting the spatial position of a cast product according to claim 4, wherein the optical sensor includes a light projector and a light receiver, is of a reflective type, and is provided directly facing the inclined surface of the convex portion or the concave portion. . 7. Claims 1, 2, 3, 4, 5, or 6, wherein the optical sensor is attached to the robot and scanned to detect the convex portion or the concave portion. A method for detecting the spatial position of a cast product as described in .