JPH047707A - Tool axis correcting system - Google Patents

Abstract

PURPOSE:To correct the tool axis of a tool head bent like a crank by correcting the rotational center of the tool head in the tool axis direction and vertical direction. CONSTITUTION:The rotational center Pc of the tool head is offset only by a tool axis correcting vector 6 to be a synthetic vector between a normal direction correcting vector 6R having length R and the direction of a normal 4 and a vertical direction correcting vector 6L having length L and the direction of a tangent 5. When the rotational center Pc of the tool head 1 is offset from a program passage after finding out the vector 6, a work 3 can be worked. In this case, the rotation of the head 1 is controlled by an axis X so that the direction of the leading part 1a of the head 1 coincides with the normal 4. Thus, the tool axis of the rotating tool head 1 vent like a crank can be corrected.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a tool axis correction method for offsetting the center of rotation of a tool head of a grinding machine, etc., and particularly for a tool that offsets the center of rotation of a tool head bent in a crank shape. Regarding axis correction method.

[Conventional technology]

There is a tool head that has a tool at the tip of a tool head, such as a grinder, and is configured so that the tool head can rotate.

These tool heads perform machining by controlling the axis of the tool head in the normal direction of the workpiece.

Here, the axis of the tool head is referred to as the tool axis. This type of control is called normal direction control, in which the tool axis is always in the normal direction of the workpiece, and a normal direction correction vector whose diameter is the distance between the rotation center of the tool head and the surface of the tool that touches the workpiece is generated. The tool axis is corrected for the center of rotation of the tool head.

[Problem to be solved by the invention]

However, there are tool heads that are bent like a crank. In such a tool head, it has not been possible to correct the tool axis of the rotation center of the tool head using only the conventional normal direction correction vector. Furthermore, some painting nozzles and the like are not straight but curved like a crankshaft, and the conventional tool axis correction method cannot be applied to the offset of these nozzles as well.

The present invention has been made in view of these points, and it is an object of the present invention to provide a tool axis correction method for the rotation center of a tool head bent in a crank shape.

Another object of the present invention is to provide a tool correction method for a tool axis that offsets a crank-shaped nozzle.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention uses a tool axis correction method that offsets the rotation center of the tool head, and calculates a normal direction correction vector that offsets the rotation center in the normal direction of the workpiece, and , find a vertical correction vector that offsets the distance from the normal line, combine the normal direction correction vector and the vertical correction vector to find a tool axis correction vector, and calculate the rotation center of the tool head. A tool axis correction method is provided that is characterized by offsetting the tool axis.

[Effect]

First, a normal direction correction vector for correcting the rotation center of the tool head in the normal direction is determined. Next, a vertical correction vector is calculated to correct the center of rotation of the tool head in a direction perpendicular to the normal line of the workpiece.

The resultant vector of both becomes the tool axis correction vector for the rotation center of the tool head to be sought. By this tool axis correction, the tool axis of the tool head is oriented in the normal direction of the workpiece, and the machining point of the tool is correctly placed at the machining point of the workpiece.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a diagram for explaining the tool axis correction method of the present invention. The tool head 1 is bent in a crank shape, and the point P
c is the center of rotation of the tool head 1. Further, there is a grinding tool 2 at the tip of the tool blade 1, and the grinding tool 2 rotates around a point Pt.

The center Pt of the grinding tool 2 is on the normal line 4 at the point Pw of the workpiece 3.
There is a grinding tool 2 in the tangential direction 5 of the workpiece 3 at point Pw.
should proceed. To this end, the tool head 1 is configured to be able to rotate around the point Pc, and is controlled so that the normal 4, that is, the orientation of the portion 1a of the tool head 1, coincides with the normal 4.

In order to satisfy this requirement, the rotation center Pc of the tool head 1 may be located at a distance R from the tangent 5 of the work 3 and at a distance from the normal 4.

In other words, the rotation center PC of the tool head is defined by a normal direction correction vector 6R having a length R and a direction of the normal line 4.
It is only necessary to offset the tool axis correction vector 6, which is a composite vector of the vertical direction correction vector 6L having a length L and a direction of the tangent 5. Therefore, by obtaining such a tool axis correction vector 6 and offsetting the rotation center Pc of the tool head 1 from the program path, the workpiece 3 can be machined. Of course, at this time, the rotation of the tool head 1 is controlled by the C-axis so that the direction of the tip portion 1a of the tool head coincides with the normal line 4.

FIG. 2 is a diagram showing an example of a program to which the tool axis correction method of the present invention is applied. Point Ps is the starting point. Second
In the figure, 7 indicates a program path, and a broken line 8 indicates a path of the rotation center Pc of the tool head.

The first program command is:

G41 GOI X10. ODOI; G42.1; Here, G41 is a tool axis correction command, Gol specifies linear interpolation, X10.0 specifies the amount of movement of the X axis, and Dol specifies the number of the normal direction correction vector. The magnitude of the normal direction correction vector at this time is 10°0 mm. The magnitude of this normal direction correction vector is stored in a nonvolatile memory within the numerical control device.

G42.1 is a normal direction tool correction command, and the grinding tool 2
A command is given to set the normal direction correction vector on the right side with respect to the traveling direction of the object. This command moves the tool center Pc in FIG. 1 to Pica. Point P1 is a moving point on the program. That is, this is the point where the grinding tool 2 and the workpiece come into contact.

The vector VIP is a normal direction correction vector, and corresponds to the normal direction correction vector 6R in FIG.

However, in FIG. 2, the direction of the normal direction correction vector VIR is shown opposite to the direction of the normal direction correction vector 6R in FIG.

Command the following program as follows.

G41.2 L5. O; Here, G41.2 is a vertical tool axis correction command,
Generate a vertical correction vector on the left side facing the normal direction. (The command to generate the vertical correction vector on the right side is G42.2.) The magnitude of this vertical correction vector is specified as 5°0 mm. This vertical correction vector VIL is the vertical correction vector 6L in FIG.
corresponds to

Due to this vertical tool axis correction command, the rotation center Pc of the tool head advances to point PIC, and the grinding tool 2 contacts the workpiece at point P1.

Next, according to the program G91 GOI X20.0;, the program path advances from point P1 to point P2,
The rotation center point Pc of the tool rad 1 advances to point P2C. Vector V2R is a normal direction correction vector, and vector V2L is a vertical direction correction vector.

Similarly, the program command GO2X20. OY-20, OR20゜0; Accordingly, the program path advances from point P2 to point P3,
The rotation center point Pc of the tool head 1 advances to point P3C. Vector V3R is a normal direction correction vector, and vector V3L is a vertical direction correction vector.

Further, due to the program command GOI Y-10,0;, the program path advances from point P3 to point P4,
The rotation center point Pc of the tool head advances to point P4C. Vector V4R is a normal correction direction vector, and vector V4L is a vertical direction correction vector.

Next, the vertical correction vector is canceled by the program command G40.2;, and the rotation center Pc of the tool head goes from P4C to P5C, and the point P
Proceed to 5C1. That is, the vertical correction vector V5L
is canceled.

Furthermore, the normal direction correction vector V5R is determined by program command G40.1. Also, according to the program command, G40X-50,O;
Both c return to point Pe.

FIG. 3 is a block diagram showing a contract function for generating a tool axis correction vector in the tool axis correction method of the present invention. The cutting program 101 is decoded by the preprocessing means 102, and the normal direction tool axis correction command is sent to the normal direction correction vector calculation means 10.
4, the vertical tool axis correction command is sent to the vertical correction vector calculation means 105.

The normal direction correction vector calculating means 104 calculates a normal direction correction vector, the vertical direction correction vector 105 calculates a vertical direction correction vector, and the respective X-axis and Y-axis components are added by adders 106a and 106b, It is sent to the interpolation means 103 as a tool axis correction vector. Interpolation means 103
is the rotation center P of the tool head 1 by adding the X-axis and Y-axis movement amounts from the preprocessing means 102 and the tool axis correction vector.
Find the moving point of C and interpolate it to obtain the interpolated pulse XP,
Output YP at regular intervals. Note that the rotation control of the C-axis is omitted in the above block diagram.

FIG. 4 is a flowchart of the tool axis correction method of the present invention. In the figure, the number following S indicates the step number.

[S1] If there is a normal direction tool axis correction command, proceed to S2,
If not, proceed to S5.

[S2] The normal direction correction vector calculation means 104 calculates a normal direction correction vector.

[S3] Check to see if there is a vertical tool axis correction command, and if so, proceed to S4; if not, proceed to S5.

[S4] The vertical correction vector calculation means 105 calculates a vertical correction vector.

[S5] The normal direction correction vector and the vertical direction correction vector are combined to obtain a tool axis correction vector, and the interpolation means 103
send to

[S6] The interpolation means 103 determines the moving point of the rotation center Pc of the tool head from the sent tool axis correction vector and movement command, performs interpolation to this point at a constant cycle, and generates an interpolation pulse XP.
, YP is output.

FIG. 5 shows a numerical control device (CNC) for implementing the present invention.
) is a block diagram of the hardware.

In the figure, 10 is a numerical control device (CNC). The processor 11 is a processor that plays a central role in controlling the entire numerical control device (CNC) 10.
Reads the system program stored in OM12,
According to this system program, the numerical control device (CN)
C) Execute overall control of 10. The RAM 13 stores temporary calculation data, display data, etc. RAM13
SRAM is used for this. CMO514 contains normal direction correction vector amount, pitch error correction amount, and machining program 1.
01, parameters, etc. are stored.

The CMO 514 is powered up by a battery (not shown) and serves as a non-volatile memory even when the numerical control unit (CNC) 10 is powered off, so its data is retained as is.

The interface 15 is an interface for external devices, and is connected to external devices 31 such as a paper tape reader, a paper tape puncher, and a paper tape reader/puncher. The cannibal program is read from the paper tape reader, and the cannibal program edited in the numerical control device (CNC) 10 can be output to the paper tape puncher.

PMC (Programmable Machine Controller) 16
is built into CNCl0 and controls the machine using a sequence program created in ladder format. That is, according to the M function, S function, and T function commanded by the machine program, these are converted into necessary signals on the machine side using a sequence program, and the signals are output from the I10 unit 17 to the machine side. This output signal drives a magnet, etc. on the machine side, and operates a hydraulic valve, a pneumatic valve, an electric actuator, etc. It also receives signals from limit switches on the machine side, switches on the machine operation panel, etc., performs necessary processing, and passes them to the processor 11.

The traffic control circuit 18 converts digital data such as the current position of each axis, alarms, parameters, and image data into image signals and outputs the image signals. This image signal is CRT/MD
It is sent to the display device 26 of the I unit 25, and the display device 2G
will be displayed. The interface 19 receives data from the keyboard 27 in the CRT/MDI unit 25,
It is passed to the processor 11.

Interface 20 is connected to and receives pulses from manual pulse generator 32 . A manual pulse generator 32 is mounted on the machine operation panel and is used to manually precisely position the machine operation.

Axis control circuits 41 to 44 receive movement commands for each axis from the processor 11, and transmit the commands for each axis to servo pumps 51 to 54.
Output to. Servo amplifiers 51-54 receive this movement command and drive servo motors 61-64 for each axis. The servo motors 61 to 64 have a built-in pulse work for position detection, and a position signal is fed back from this pulse work as a pulse train. In some cases, a linear scale is used as a position detector.

Further, by performing F/V (frequency/velocity) conversion on this pulse train, a velocity signal can be generated. In the figure, these position signal feedback lines and velocity feedback are omitted.

Here, the servo motors 61, 62, 63 and 64 are servo motors around the X-axis, Y-axis, Z-axis, and C-axis, respectively.

The spindle control circuit 71 receives a spindle rotation command, a spindle orientation command, etc., and outputs a spindle speed signal to the spindle amplifier 72. The spindle amplifier 72 receives this spindle speed signal and
The spindle motor 73 is rotated at the commanded rotation speed. Further, the spindle is positioned at a predetermined position by an orientation command.

A position work 82 is connected to the spindle motor 73 by a gear or a belt. Therefore, the position workpiece 82 rotates in synchronization with the spindle 73 and outputs a feedback pulse, which is read by the processor 11 via the interface 81. This feedback pulse is used to move other axes in synchronization with the spindle motor 73.

FIG. 6 is a diagram showing an example of applying the present invention to a coating nozzle. The nozzle 111 is bent into a crank shape. Further, the nozzle 111 can be rotated in the B-axis direction on the paper surface,
Furthermore, it can rotate about line 112 in the C-axis direction and about line 118 in the A-axis direction. Therefore, the rotation center of the nozzle 111 may be offset La from the point pp of the workpiece 113 in the normal direction and in the tangential direction Ra1. This offset is performed on a plane determined by the direction of line 114 and command block 115. In other words, when viewed from the nozzle rotation center Pm toward the tip of the nozzle 111 so that the direction of movement of the command block is to the right on a plane 116 determined by the direction of the line 114 and the command block 115, when correcting to the left is G41.2, and the case of correction in the right direction is 042°2. This kind of offset control is a three-dimensional offset, but if you decide on the left and right directions to be corrected from the plane where the offset is performed as described above, it can be used as a tool axis correction on a two-dimensional plane as explained above. are the same,
Corrections can be made in a similar manner.

The A-axis of the rotational axis is also controlled so that the direction in which the nozzle 111 is bent in a crank shape, that is, the line 117 is on the plane in which the above-described offset is performed.

In addition, in the explanation of Fig. 3, only the two-axis control of tXp and Yp, which was a two-dimensional offset, was explained, but when performing the above three-dimensional offset, it is XpSYp.
Of course, zp is added in the same way.

In the above description, the normal direction tool axis correction and the vertical direction tool axis correction are commanded separately, but it is also possible to configure so that both can be commanded simultaneously with one block of commands.

Moreover, although the description has been made using a grinder as a two-dimensional example and a painting nozzle as a three-dimensional example, it goes without saying that the invention can also be applied to similar types of tool heads, nozzles, arms, etc.

〔Effect of the invention〕

As explained above, in the present invention, the center of rotation of the tool head is corrected in a direction perpendicular to the tool axis direction, so that it is possible to correct the tool axis of a tool head bent in a crank shape.

It can also be applied to a crank-shaped painting nozzle.

[Brief explanation of drawings]

Figure 1 is a diagram for explaining the tool axis compensation method of the present invention, Figure 2 is a diagram showing an example of a program to which the tool axis compensation method of the present invention is applied, and Figure 3 is a diagram for explaining the tool axis compensation method of the present invention. FIG. 4 is a flowchart of the tool axis correction method of the present invention, and FIG. 5 is a block diagram showing the function of generating the tool axis correction vector of the present invention.
), and FIG. 6 is a diagram showing an example in which the present invention is applied to a painting nozzle. Tool head Grinding tool Work Tool axis correction vector Vertical correction vector Normal direction correction vector Processor OM AM MOS Interface 4 1 to 44 5 1 to 54 6 1 to 64 PMC (Programmable Machine Controller) I10 unit Taraphic control circuit interface Interface axis control circuit servo amplifier servo motor spindle control circuit spindle amplifier spindle motor interface position work addition program preprocessing means interpolation means normal direction correction vector operator stage vertical direction correction vector operator stage nozzle work

Claims (7)

[Claims] (1) In a tool axis correction method that offsets the rotation center of the tool head, a normal direction correction vector that offsets the rotation center in the normal direction of the workpiece is determined, and the distance between the rotation center and the normal line is offset. A tool axis characterized in that: a vertical correction vector is determined, the normal direction correction vector and the vertical correction vector are combined to obtain a tool axis correction vector, and the rotation center of the tool head is offset. Correction method. (2) The tool axis correction method according to claim 1, wherein the normal direction correction vector and the vertical direction correction vector are programmed with separate commands. (3) The tool axis correction method according to claim 1, wherein the tool axis correction vector is obtained on a plane. (4) The tool axis correction method according to claim 1, wherein the tool axis correction vector is obtained as a vector in a three-dimensional space. (5) The tool axis correction method according to claim 4, wherein the vector in the three-dimensional space is generated within a plane that includes the normal direction vector and the direction of the command block. (6) The tool axis correction method according to claim 4, characterized in that a rotation axis is rotated to orient the vertical offset direction of the tool axis in the direction of the vertical correction vector. (7) The tool axis correction method according to claim 4, wherein the tool axis correction vector is determined as a nozzle correction vector.