JP2593464B2 - Machine path tracking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to a processing locus preliminarily drawn on a three-dimensional workpiece when performing trimming processing or hole processing by laser processing. The present invention relates to a machining trajectory tracking device capable of accurately and automatically performing teaching along a marking line as described above, and having good reproducibility after teaching.

(Conventional technology) Conventionally, when performing, for example, a trimming process or a hole process on a three-dimensional work, a marking line is previously formed as a processing locus on the target work, and teaching is performed while tracking the processing locus. I have. In other words, for teaching, the operator inserts a marking line as a machining trajectory into the target work in advance, and while the operator sees the marking line, he brings the teaching device head to the teaching point and controls the position and posture to process. The trajectory data is input to, for example, a control device of a laser processing machine.

(Problems to be Solved by the Invention) However, in the teaching performed while tracking the processing locus described above, it is very difficult to measure and determine the position and orientation for obtaining the processing locus, and it takes a considerable time. . In particular, when the three-dimensional work has a complicated shape, the number of teaching points increases, so that it takes a long time for teaching and more mistakes are present.

Thus, in the case of high-mix low-volume production, the setup time is prolonged, and the production efficiency is a major factor that significantly reduces the production efficiency.

Also, in the optical sensor system, it is difficult to directly measure the position and orientation of the marking line because the surface condition is not constant due to dust, oil, rust, or the like, and there are many measurement errors.

[Structure of the Invention] (Means for Solving the Problems) In view of the above-described conventional problems, the present invention includes a detection head that is used by being detachably replaced with a processing head provided in a laser processing machine. A tracking trajectory tracking device for a workpiece, wherein the detection head is on a plane parallel to a tangent plane including the arbitrary point on the marking line drawn on the workpiece and in contact with the workpiece and passing through the point; A light emitting body is provided on a line perpendicular to the light emitting body, and a plurality of pairs of light position detectors for receiving reflected light of irradiation light emitted from the light emitting body to the marking line are provided on the plane, and the plurality of light An arithmetic unit is provided for calculating a distance between the tangent plane and the detection head and a tilt of the detection head with respect to the tangent plane based on a detection value of a position detector.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1 and FIG. 2, a plurality of, for example, four columns 3 are erected on one floor of a laser beam machine M. A support plate 5 is placed on the column 3. A plurality of, for example, two X-axis guides 7 are attached on both sides of the support plate 5 in the X-axis direction which is the left-right direction in FIG. A plurality of, for example, two support plates 9 are mounted between the two X-axis guides 7 in the Y-axis direction, which is the vertical direction in FIG. 2, and the support plates 9 support the X-axis guides 7. Two X-axis guides 7
An X-axis carriage 11 that moves in the X-axis direction is mounted on the X-axis carriage 11, and the X-axis carriage 11 has a Y-axis carriage 13.
Has been posted. Y axis carriage 13 is X axis carriage
It is moved in the Y-axis direction along a guide 15 surface provided parallel to the side of 11. A Z-axis column 17 is mounted in the Z-axis direction, which is substantially in the center of the Y-axis carriage 13 and is vertical,
In addition, the Z-axis column 17 moves in the Z-axis direction along a guide mounted in the Y-axis carriage 13.
A processing head 19 is mounted on the distal end side of the Z-axis column 17 as shown in FIG.

The laser beam is emitted from a nozzle tip 21 attached to the tip of the processing head 19 as shown in FIG. As shown in FIG. 2, a three-dimensional work W (hereinafter simply referred to as a work) is provided in a working area 23 provided below between the X-axis guides 7 and between the support plates 9.
Is placed. Safety cabin 25 to cover each device
Are provided around the machine body. On the outside of the machine body, as shown in FIGS. 1 and 2, a pneumatic unit device
27, a numerical controller 29 and a laser oscillator power supply 31 are provided, and the numerical controller 29 is rotated around A-axis and Y-axis which are rotated around X-axis, Y-axis, Z-axis, X-axis (not shown). And is connected to each drive device of the B axis to control each drive shaft. As shown in FIGS. 1 and 2, a laser oscillator head 33 is mounted on the right support plate 9 and is connected to the laser oscillator power supply 31 via a connecting pipe 35.

A processing head 19 is detachably attached to a lower portion of the Z-axis column 17. For example, instead of the processing head 19, a detection head H of a tracking device, which is a main part of the present embodiment, is detachably attached. It can be attached.

FIG. 3 shows the relative positional relationship between the workpiece W and the detection head H of the tracking device. In FIG. 3, the example of the hat-shaped workpiece W, as Eka by scribe lines W _L as processing locus to be processed in advance, for example, an operator. Its scribe line W _L as machining path is formed by filling in the groove phosphorescence paint as as light-emitting material, which will be described in detail later.

Now, as a starting point to be processed the point P of the scribe line W _L,
A tangent plane including the starting point P is defined as T. When the coordinate axes of the starting point P in the machine coordinate system are X, Y, and Z axes, and the coordinate axes in the tangent plane T are the x, y, and z axes, the tangent plane T is an xy plane.

Now, it is assumed that the light receiving plane R of the detection head H is located at a position apart from the tangent plane T by a distance d, and the center point of the light receiving plane R is Q. On the light receiving plane R, a plurality of sensors for coordinate detection, for example, four position-sensitive devices PSD (referred to as optical position detectors) are arranged in a cross at intervals of 90 degrees. That is, the four PSD as shown in FIG. 3, Yes arranged in order in the clockwise direction, PSD ₁ and PSD _3, PS
D ₂ and PSD ₄ are respectively symmetrical on a straight line.

A plane including the center point Q of the light receiving plane R and parallel to the tangent plane T is represented by S, and coordinate axes of a plane S parallel to the x, y and z axes of the tangent plane T are x ′, y ′ and z ′. Axis. Further, the axis of the detection head H is a line PQ connecting the point P and the point Q, and the line PQ is the x, y and z of the tangent plane T.
Assume that they are at angles α, β and γ with respect to the axis, respectively.

'The angle between the axis theta _x, straight line y connecting the PSD ₂ and PSD _4' PSD ₁ and the straight line and the x connecting the PSD ₃ of the light receiving plane R containing PSD ₁ ~PSD ₄ the angle between the axis Is θ _y .

Here, four PSD i.e., to ensure that each PSD _1, PSD _2, PSD ₃ and PSD ₄ receives the uniform reflected light is preferably controlled to be θ _x = θ _y = 0 do it. That is, the light receiving plane R overlaps the plane S, and the plane S
And the tangent plane T are parallel to each other.
, The reflected light is evenly obtained in the four PSDs.

As described above, the point P has the coordinates of the X, Y, and Z axes in the machine coordinate system, and if the θ _x and θ _y are appropriately controlled, the vector of the axis PQ of the detection head H can be obtained. Of course, ▲ ▼ can be controlled in any direction.

Thus, if the light receiving plane R is parallel to the tangent plane T, the vector ▼ corresponds to the z-axis. That is, the vector ▲
▼ is perpendicular to the tangent plane T.

Therefore, a position where the light receiving plane R of the detection head H is separated from the tangent plane T by a distance d is detected, and the light receiving plane R is parallel to the tangent plane T and the detection head H
, The position and orientation of the detection head H can always be kept constant and controlled with respect to the machining trajectory.

Before describing the specific means for detecting the position and orientation of the scribe line W _L for example a point on the P as a processing path of the workpiece W by the detection head H, it is used to detect the head H
The principle of PSD will be briefly described.

FIG. 4 shows a sectional structure of one PSD. In FIG. 4, the PSD is a high-resistance Si substrate (i-layer) made of silicon or the like and one or both surfaces of a high-resistance semiconductor are formed of a uniform resistance layer, and a pair of electrodes A for signal extraction are provided at both ends of the layer. , B are provided. The surface layer also forms a PN junction and has a photoelectric effect.

The distance between the electrodes A and B of the PSD is L, the resistance is R _L ,
The distance from the electrode A to the light incident position is X, and the resistance of that part is
Let it be R _x . The photo-generated charges generated at the light incident position reach the resistance layer as a photocurrent proportional to the incident energy of the light,
It is divided so as to be in inverse proportion to the resistance value to each electrode, and extracted from the electrodes A and B. The photocurrent generated by the incident light and I _O, the current extracted to the electrodes A and B I _A, When I _B, Becomes

Assuming that the resistance layer is uniform and the length is proportional to the resistance value, Is represented by

I _A, when determining the ratio of I _B, Next, in which I _A, from the value of I _B, can be known irrespective incident position of light incident energy.

Measurement of the position and orientation of the workpiece W by the detection head H using the PSD based on the above-described principle will be described.

FIG. 5 shows the position and posture of the detection head H with respect to the workpiece W.

In FIG. 5, as described with reference to FIG.
A semiconductor laser diode LD that emits invisible light is disposed at a central point Q of the laser diode. Moreover, the center point Q on the light receiving plane R
And PSD ₁ and PSD _3, PSD ₂ and PSD ₄ respectively are arranged crosswise every 90 degrees so as to be symmetrical about the.

A semiconductor laser diode for example convex projection lens for focusing the laser beam emitted from the laser diode LD is below and in the vicinity in the fifth diagram of LD were reflected in each vicinity below the PSD ₁ ~PSD ₄ For example, a convex light receiving lens for receiving laser light is arranged. further,
In the vicinity of the lower part of the light projecting lens and the light receiving lens, for example, a convex tunnel lens having a hole in the center is arranged.

On the other hand, the workpiece W, as described in the first figure, Eka has scribe lines W _L, on the scribe line W _L are formed in substantially irregular reflection surface.

As described above, in the detection head H disposed with respect to the work W, the laser light emitted from the semiconductor laser diode LD passes through the light projecting lens, and is further condensed through the hole penetrated through the center of the tunnel lens. substantially irregular reflection surface, for example 0.2mmφ following spot image on the scribe line W _L of the workpiece W is made.

By the scribe line W _L of the workpiece W has a substantially irregular reflection surface, the illumination of the illuminated surface from the light source is proportional to the cosine of the tilt angle of the surface, and viewing the illuminated surface as a new light source when, based on the principle luminance is constant even when observed from any direction to a point in the plane, the reflected light is received by the PSD ₁ ~PSD ₄ which are arranged on the same light receiving plane R through the light receiving lens You.

Since PSD ₁ ～PSD ₄ is a sensor to know the position of the incident light spot on the detector head H, the positional information flows to the pair of electrodes A, B provided at both ends of each PSD such as described in Figure 4 It is obtained as a current value.

That is, the current I _A1 of the A and B electrodes of PSD ₁ and PSD ₃ ,
I _B1, I _A3, I _B3 passes through the head amplifier HA _1, is input to the arithmetic unit C. Similarly, the current of the A and B electrodes of PSD ₂ and PSD _{4
I A2, I B2, I A4} , I B4 passes through the head amplifier HA _2, is input to the arithmetic unit C.

In the arithmetic unit C, Is performed, d = k × V (k: constant).

That is, the distance d between the scribe line W _L of the PSD and the workpiece W to be receiving point of the detecting head H is obtained.

Note that the above equation The purpose of dividing by is to normalize the effect of the amount of light.

As described above, the detection head H includes four PSDs arranged on the same plane, a light receiving lens of each PSD, a semiconductor laser diode LD, and the semiconductor laser diode.
The light projecting lens and the tunnel lens of the LD are set and assembled in advance, and the focal lengths of the light receiving lens and the tunnel lens are predetermined. Therefore, the adjustment of the position d of the detection head H with respect to the work W is performed by adjusting the position of the tunnel lens. focus so that is performed to come on the marking line W _L of the workpiece W.

The measurement of the attitude of the detection head H will be described.
As explained in the figure, a straight line connecting PSD ₁ and PSD ₃ , PSD ₂ and PS
X-axis tangent plane T D ₄ a straight line connecting for point P on the scribe line W _L of each work is W, the inclination to the y-axis theta _x, theta _{y
If, θ x = (I A1 +} I B1) - (I A3 + I B3) = n x × V θ y = (I A2 + I B2) - (I A4 + I B4) = n y × V , and the distance d Similarly, the inclinations θ _x and θ _y are obtained.

However, n _x, n _y: constant, V: voltage The inclination θ _x, θ _y is processed is input to the tracking control unit T.

Next, as shown in FIG. 3 on the workpiece W Egaki the scribe line W _L, to form a substantially light-emitting surface of the scribe line W _L as shown in FIG. 5, for example Egai the scribe line W _L groove Phosphorescent paint W _T
Fill.

As a means for filling the coating material W _T phosphorescent into the groove, a cylinder 37 filled with paint W _T of as shown in FIG. 6 for example phosphorescence is used. Needle 39 at the tip of cylinder 37
Is is provided with, so that the coating material W _T of the needle 39 Kararin light is ejected.

A dispenser 43 for controlling the flow rate is connected to the rear end of the cylinder 37 via a tube 41, and a filter regulator 47 is connected to the dispenser 43 via a tube 45. Further, an air source (not shown) is connected to the filter regulator 47 via a tube 49.

A switch 51 is provided on a right side wall of a part of the cylinder 37 in FIG. 6, and the switch 51 is connected to the dispenser 43 via a cable 53.

With the above configuration, the operator holds the cylinder 37 in his hand and manually operates the switch 51 to send air from an air source (not shown) to the dispenser 43 via the tube 49, the filter regulator 47, and the tube 45. The flow rate of the air is adjusted by the dispenser 43, and the air is supplied into the cylinder 37 via the tube 41. By the air supplied to the cylinder 37, the phosphorescent paint filled in the cylinder 37 is discharged from the needle 39 by finely controlling the discharge amount of the paint in accordance with the drawing speed, and the work W
Becomes filled in the groove of the scribe line W _L are for example, the machining path of about 0.5~0.8mm is fractionated.

Although an example has been described in which the operator operates the cylinder 37 while holding it with the hand, the cylinder 37 may be attached to a robot hand for drawing.

As the phosphorescent paint, for example, a paint that emits red phosphorescent light in response to infrared rays as invisible light is used. Further, a fluorescent paint may be used instead of the phosphorescent light. As the phosphorescent paint, for example, a paint obtained by mixing ZnS with a special component is used. In this case, ultraviolet light is always applied, and when it is irradiated with infrared light, it looks red.

After the pre Eka paint W _T of e.g. phosphorescence in the groove of the scribe line W _L of the workpiece W was filled in the cylinder 37, moves the detection head H as tracking devices on the starting point P of the scribe line W _L Then, the position d of the detection head H is adjusted with respect to the tangent plane T including the point P. That is, the distance d at which the focal point of the tunnel lens is focused on the tangent plane T of the point P, and the above θ _x = θ _y =
0, that is, the posture of the detection head H is controlled in the direction perpendicular to the tangent plane T, and the data of the position and posture are processed by the tracking control device T.

While maintaining the detection head H is the distance d constant, is to be moved sequentially in substantially follow the above light-emitting surface perpendicular scribe lines W _L always work W.

Therefore, by setting the predetermined sampling time, with the point data on scribe lines W _L as a processing path, the point data is processed by the arithmetic unit C.

At this time, since the sampling time is constant, when the movement of the detection head H is fast, the distance between trace points is large, and when the movement of the detection head H is slow, the distance between points is small, so that a finer trace can be performed.

The portion of the workpiece W having a complicated shape causes the detection head to move slowly. Therefore, the trace points in that case are necessarily finer, and conversely, the straight line portions are coarser.

Thus, each coordinate of the trace point of the detection head H is processed by the arithmetic unit C, and the processed data is used as a numerical control device 29 having a tracking function in the laser beam machine M.
And correction processing is performed on the machine coordinate system of the laser beam machine M. Next, the detection head H is removed, the processing head 19 is attached, and the work W to be further processed is set in the same manner as the work for which data has been previously collected, and the laser processing machine M is traced, that is, using the teaching data. Is controlled by X, Y, Z, A and B axes,
Uniform copying can be performed.

Note that when tracing example teaching the detection head H, travels in a zigzag manner with respect to the marking line W _L, 4
The position of each measurement point is detected by controlling the average value of the sum of the intensities of the two PSDs.

Thus, to form a scribe line W _L of the workpiece W as a nearly emission surface, while retaining the detecting head H from the teaching point on the marking line W _L at a constant distance d, and the posture of the detecting head H each Because it can be controlled in the vertical direction to the tangent plane of the teaching point,
Automatic tracking of the detection head H as a tracking device is facilitated.

As a result, teaching of a work locus of, for example, trimming or drilling of a workpiece can be automatically performed, and teaching time can be significantly reduced. In addition,
For example, since the width of the phosphorescent paint is the same as the width of the marking line, accurate measurement can be performed, so that teaching accuracy is also improved.

Further, since the scribe lines W _L as processing regulation is formed by filling a visible light emission material e.g. phosphorescence paint,
When the invisible light is irradiated on the processing locus, the phosphorescent paint can be visually observed in red, so that the spot position on the marking line W can be easily confirmed in a dark place such as at night. In addition, since the status of the automatic tracking can be followed with the eyes, the operation is simplified, and errors are reduced.

The present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes.

[Effects of the Invention] As can be understood from the above description of the embodiments, in short, the present invention relates to a detection head ( H), wherein the detection head (H) includes an arbitrary point (P) on a marking line (W _L ) drawn on the work (W). W) on a plane (S) parallel to the tangent plane (T) tangent to the tangent plane (T) and passing through the point (P) and perpendicular to the tangent plane (T).
Q) A light-emitting body (LD) is provided on top of the light-emitting body (L
D) a plurality of pairs of optical position detectors (PSDs) for receiving reflected light of irradiation light emitted from the marking line (W _L ) to the marking line (W _L ) on the plane (S); Vessel (PS
A calculation unit (C) for calculating a distance between the tangent plane (T) and the detection head (H) and a tilt of the detection head (H) with respect to the tangent plane (T) based on the detection value of D); It is.

As is clear from the above configuration, in the present invention, the detection head H is used by being detached and replaced with the processing head 19 in the laser processing machine, and is provided at an arbitrary point P on the marking line drawn on the workpiece W. A light emitter is provided on a line PQ passing through the point P and orthogonal to the tangent plane T on a plane S parallel to a tangent plane T in contact with the workpiece W, and is irradiated from the light emitter to the marking line. A plurality of pairs of optical position detectors for receiving reflected light of the irradiated light are provided on the plane S.
Then, based on the detection values of the plurality of pairs of optical position detectors, the distance from the tangent plane and the detection head H with respect to the tangent plane
Is provided.

Therefore, according to the present invention, the marking head can be detected by the detection head H under the same conditions as when laser processing is performed by the processing head 19 of the laser processing machine. The teaching of the machining locus can be automatically and accurately performed.

That is, when teaching a marking line using the detection head H in place of the processing head 19 in the laser processing machine, the distance from the work to the detection head H is controlled to be constant, and the axis of the detection head H with respect to the work is controlled. Teaching can be performed while keeping the heart in the normal direction at all times. After teaching, it is sufficient to replace the processing head 19 again and perform laser processing, and the reproducibility after teaching is good.

[Brief description of the drawings]

FIG. 1 is a front view of a laser beam machine according to one embodiment of the present invention, and FIG. 2 is a plan view of FIG. FIG. 3 is a diagram showing a relative positional relationship between a work and a tracking device detection head for explaining the present invention. FIG. 4 is an explanatory diagram for explaining the principle of the detection head used in the present invention. FIG. 5 is an explanatory diagram for explaining the present invention. FIG. 6 is a view showing an example of an apparatus for filling a paint used for forming a light emitting surface substantially along a processing locus of a workpiece. [Explanation of reference numerals indicating main parts of drawings] W: Work W _L: Marking line W _T: Phosphorescent paint H: Detection head T: Tangent plane R: Light receiving plane PSD: Position sensitive Device LD: Semiconductor laser diode C: Operation unit

Claims (1)

(57) [Claims] 1. A device for tracking a machining trajectory on a workpiece, comprising a detection head (H) used by being detachably replaced with a processing head (19) provided in a laser processing machine (M), wherein the detection head (H) ) Is on a plane (S) parallel to a tangent plane (T) in contact with the work (W) including an arbitrary point (P) on the marking line (W _L ) drawn on the work (W). And a line (P) passing through the point (P) and perpendicular to the tangent plane (T).
Q) A light-emitting body (LD) is provided on top of the light-emitting body (L
D) a plurality of pairs of optical position detectors (PSD) for receiving reflected light of irradiation light emitted from the marking line (W _L ) to the marking line (W _L ) on the plane (S); Vessel (PS
A calculation unit (C) for calculating a distance between the tangent plane (T) and the detection head (H) and a tilt of the detection head (H) with respect to the tangent plane (T) based on the detection value of D); A machining path tracking device for a workpiece, comprising: