JP7328474B1 - Numerical controller - Google Patents

Abstract

A numerical control device according to one aspect of the present disclosure specifies a position offset by a predetermined set distance in a direction perpendicular to the surface of a workpiece from a machining point based on a detection value of a gap detector for each control cycle. Alternatively, an ideal specific value group calculation unit that calculates an ideal specific value group that is a specific value group consisting of a plurality of numerical values, and an execution that is a specific value group that indicates the position where the machining head is actually arranged based on the ideal specific value group and an execution specific value group calculation unit for calculating the specific value group, wherein the execution specific value group calculation unit uses the evaluation value indicating the relationship between the current ideal specific value group and the execution specific value group one cycle before as a predetermined criterion. value, the current execution specific value group is set to the same specific value group as the current ideal specific value group, and if the evaluation value of the current ideal specific value group exceeds the reference value, the current execution specific value group Let the value group be a specific value group in which the distance from the machining point is the set distance and the evaluation value is equal to the reference value.

Description

The present invention relates to numerical controllers.

In general, when machining a workpiece by relatively moving the machining head and the workpiece, it is required to offset the machining head from the workpiece by a certain distance. As an example, in laser machining, it is desirable to maintain a relatively tight offset distance of the machining head relative to the focal length of the laser. In order to precisely maintain the offset of the processing head at a constant distance, a detector installed in the processing head detects the distance between the processing head and the work, and the position of the processing head is adjusted to keep the distance between the processing head and the work constant. has been proposed (see Patent Literature 1, for example).

JP 2017-192970 A

It is desirable to offset the machining head in the normal direction of the machining point on the surface of the workpiece. Depending on the surface shape of the workpiece, the normal direction at the machining point may change sharply, which may cause abnormal vibrations in the machining apparatus.

A numerical control device according to an aspect of the present disclosure includes a machining head for machining a workpiece, a drive mechanism for relatively moving the workpiece and the machining head, a gap detector for detecting the distance between the workpiece and the machining head, A movement control unit for relatively moving the work and the processing head so as to change the position of the processing point on the work to be processed by the processing head, and a control cycle A specific value group consisting of one or more numerical values that specifies a position offset by a predetermined set distance in a direction perpendicular to the surface of the workpiece from the machining point based on the detection value of the gap detector for each. An ideal specific value group calculation unit that calculates an ideal specific value group, and an execution specific value that calculates an execution specific value group, which is a specific value group indicating a position where the machining head is actually arranged, based on the ideal specific value group. and a group calculation unit, wherein the execution specific value group calculation unit calculates when an evaluation value indicating a relationship between the current ideal specific value group and the execution specific value group one cycle before is equal to or less than a predetermined reference value. sets the current execution specific value group to the same specific value group as the current ideal specific value group, and if the evaluation value of the current ideal specific value group exceeds the reference value, the current execution specific value group be a specific value group in which the distance from the machining point is the set distance and the evaluation value is equal to the reference value.

1 is a schematic configuration diagram of a machining system including a numerical controller according to an embodiment of the present disclosure; FIG. FIG. 2 is a schematic diagram showing a relationship between an ideal specific value group and an execution specific value group calculated by the numerical controller of FIG. 1;

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a machining system 1 including a numerical controller 20 according to an embodiment of the present disclosure. The processing system 1 includes a processing device 10 and a numerical controller 20 that controls the processing device 10 .

The processing apparatus 10 includes a processing head 11 that processes a work W, a work holding unit 12 that holds the work W, a drive mechanism 13 that relatively moves the work W held by the work holding unit 12 and the processing head 11, and a gap detector 14 for detecting the distance between the workpiece W and the machining head 11 .

The processing head 11 may be, for example, a laser head that irradiates the workpiece W with a laser, a cutting head that has a rotary tool, or the like. It is preferable that the output of the processing head 11 , such as the intensity of the laser beam, the torque of the rotary tool, etc., be adjusted by the numerical controller 20 .

The work holding unit 12 only needs to be able to hold the work W, and may be configured to have a table, a chuck, or the like, for example. In the illustrated embodiment, the workpiece holder 12 is contemplated to have a chuck that holds the workpiece W and is rotated by the drive mechanism 13 .

The drive mechanism 13 is configured to move the machining head 11 and the work W relative to each other so as to move the machining point where the work W is machined by the machining head 11 . In the present embodiment, the drive mechanism 13 includes a rotation drive mechanism 131 that rotates the workpiece W by rotating the workpiece holder 12 to change the position of the machining point on the workpiece W facing the machining head 11 . In the illustrated embodiment, the rotation drive mechanism 131 rotates the work W held by the work holding section 12 around an axis C perpendicular to the plane of the paper. Further, the drive mechanism 13 is configured to be able to adjust the distance between the processing head 11 and the workpiece W. In this embodiment, the drive mechanism 13 includes an orthogonal coordinate system drive mechanism 132 having a plurality of drive axes that change the position and orientation of the machining head 11 . Note that the drive mechanism 13 is not limited to these configurations, and may have any configuration including, for example, an articulated robot or the like that moves the processing head 11 or the workpiece holder 12 .

The gap detector 14 is preferably provided on the machining head 11 in order to measure the distance between the machining head 11 and the workpiece W with high accuracy. As the gap detector 14, for example, a capacitance sensor, a laser sensor, an ultrasonic sensor, or the like can be used.

Numerical control device 20 may be implemented by one or more computer devices having a memory, a processor (CPU), an input/output interface, etc., and executing an appropriate control program. The components of the numerical control device 20 described below are categorized functions (operations of the processor) of the numerical control device 20, and may not be clearly classified in terms of physical configuration and program configuration.

The numerical controller 20 includes a movement control section 21 , an ideal specific value group calculation section 22 , an execution specific value group calculation section 23 , a gap control section 24 and an output adjustment section 25 .

The movement control unit 21 relatively moves the workpiece W and the machining head 11 so as to change the position of the machining point on the workpiece W to be machined by the machining head 11 . In this embodiment, the movement control unit 21 rotates the chuck of the work holding unit 12 to rotate the work W about the axis C, thereby moving the position of the processing point facing the processing head 11. It is contemplated that However, the movement control unit 21 may move the machining point by operating the machining apparatus 10 to change the position of at least one of the workpiece W and the machining head 11 .

The ideal specific value group calculation unit 22 calculates a position offset by a predetermined set distance in a direction perpendicular to the surface of the workpiece W from the machining point, that is, the machining head 11 An ideal specific value group, which is a specific value group consisting of one or a plurality of numerical values that specify the ideal position of , is calculated. The position of the processing head 11 can be the position of the tip of the main body excluding tools and the like. The "specific value group" is a set of one or more numerical values representing the position of the machining head 11, and may be a single angle, vector, or the like based on the position of the machining point, or a non-moving coordinate system. may be coordinates in The "specific value group" is preferably a vector whose starting point is the position of the machining point so that the movement of the machining head 11 in one control cycle can be easily grasped.

The ideal specific value group calculator 22 calculates the orientation of the surface of the workpiece W at the machining point in consideration of the movements of the machining head 11 and the workpiece W. Specifically, the ideal specific value group calculation unit 22 calculates the detection value of the gap detector 14 one cycle before, the detection value of the gap detector 14 this time, and the machining head 11 and workpiece from one cycle before. Based on the amount of movement of W and , it is possible to specify where the machining point of one cycle before is currently. Furthermore, the ideal specific value group calculation unit 22 determines that the inclination of the straight line connecting the machining point one cycle before and the current machining point is the surface direction of the workpiece W at the current machining point, and is separated from the machining point by a predetermined set distance. can be calculated.

The execution specific value group calculation unit 23 calculates an execution specific value group, which is a specific value group indicating the position where the machining head 11 is actually arranged, based on the ideal specific value group. When the position indicated by the current ideal specific value group and the position indicated by the execution specific value group one cycle before are far apart, the execution specific value group calculation unit 23 calculates the position indicated by the current ideal specific value group. An execution specific value group that specifies a position closer to the position indicated by the execution specific value group one cycle before is set. As a result, abrupt movement of the machining head 11 is suppressed, and abnormal vibration of the machining device 10 is prevented.

Specifically, when the evaluation value indicating the relationship between the current ideal specific value group and the execution specific value group one cycle before is equal to or less than a predetermined If the specified value group is the same specified value group as the current ideal specified value group, and the evaluation value of the current ideal specified value group exceeds the reference value, the current execution specified value group is set at the set distance from the processing point. and the evaluation value is equal to the reference value.

The "evaluation value" is relatively simple, and is the angle difference between the vector of the ideal specific value group and the vector of the execution specific value group, the magnitude of the difference vector between the vector of the ideal specific value group and the vector of the execution specific value group, and the ideal specific value. It can be the distance between the position indicated by the group and the position indicated by the execution specific value group. Among others, the amount of movement of the processing head 11 can be grasped relatively easily and accurately by calculating the angle difference between the vectors as the evaluation value. In this case, the reference value is the upper limit of the angular difference between the vector of the ideal specific value group and the vector of the execution specific value group. It may be calculated from a value set by the user as the upper limit value of the distance between the indicated position of the machining head 11 and the position of the machining head 11 indicated by the execution specific value group one cycle before.

When the specific value group is a three-dimensional vector from the processing point to the position where the processing head 11 is arranged, the distance from the processing point by the execution specific value group calculation unit 23 is the set distance and the angle of the vector that is the evaluation value An example of a method of calculating a specific value group in which the difference is equal to the reference value will be described in more detail with reference to FIG. FIG. 2 shows an example in which the rotation of the workpiece W moves the machining point, and the orientation of the surface of the workpiece W at the machining point and the movement speed of the machining point change due to the workpiece W having a corner.

FIG. 2 shows a current ideal specific value group vector V1i, an execution specific value group vector V0e that matches the ideal specific value group one cycle before, a newly set execution specific value group vector V1e, and each vector The X-, Y-, and Z-direction components of are attached with x, y, and z subscripts for distinction. Also, the reference value of the angle difference between the vectors is assumed to be θ.

The vector V1e of the new execution specific value group is obtained by dividing the vector V0e of the execution specific value group one cycle before, this vector V0e and the current ideal specific value group vector into V1i with reference values centered on the axis perpendicular to both V1i. It is calculated by rotating by a certain angle θ. For this purpose, first, the vector ver, which is the central axis for rotating the vector V0e, is calculated as the outer product of the vector V0e and the vector V1i, as shown in Equation 1 below.

Subsequently, the magnitude norm of the vector ver is calculated as in the following formula 2, and each component of the vector ver is converted into a unit vector Vu by dividing the vector magnitude by the norm as in the following formula 3. .

By using this unit vector Vu and rotating the vector V0e by the angle θ as shown in the following Equation 4, the vector V1e of the execution specific value group in the current control cycle can be calculated.

Also, the reference values are the position of the machining head 11 indicated by the vector V1i of the current ideal specific value group (the end point of the vector V1i) and the position of the machining head 11 indicated by the vector V0e of the execution specific value group one cycle before (vector V0e is given as the upper limit value D of the distance to the end point of ( ), and the set distance is G, the angle difference θ of the vectors can be expressed by the following Equation 5.

The gap control unit 24 arranges the machining head 11 at the position indicated by the current execution specific value group. More specifically, the gap control unit 24 calculates the drive amount of each axis of the drive mechanism 13 necessary for arranging the machining head 11 at the position indicated by the current execution specific value group, and controls the drive mechanism 13 .

The output adjustment unit 25 calculates the moving speed of the machining point when the machining head 11 passes through the position indicated by the execution specific value group, and adjusts the output of the machining head in consideration of the moving speed of the machining point. More specifically, the output adjustment unit 25 reduces the output of the processing head, for example, the intensity of the laser, when the moving speed of the processing point is low, and increases the output of the processing head when the moving speed of the processing point is high. . As a result, the degree of processing of the workpiece W at the processing point can be made uniform.

As described above, the machining system 1 including the numerical control device 20 can suppress the amount of movement of the machining head 11 in one control period, so that vibration can be suppressed and accurate machining can be performed.

The following additional remarks will be disclosed with respect to the above embodiment and modifications.
(Appendix 1)
A numerical controller (20) comprises a machining head (11) for machining a workpiece (W), a drive mechanism (13) for relatively moving the workpiece (W) and the machining head (11), and a mechanism for controlling the workpiece (W) and the machining head (11). A gap detector (14) for detecting the distance (11), and a numerical control device (20) for controlling a machining device (11), which is a machining point on a workpiece to be machined by the machining head (11) A movement control unit (21) that relatively moves the work (W) and the processing head (11) so as to change the position of the work (W), and based on the detection value of the gap detector (14) for each control cycle, the work from the processing point to the work an ideal specific value group calculation unit (22) for calculating an ideal specific value group, which is a specific value group consisting of one or more numerical values for specifying a position offset by a predetermined set distance in a direction perpendicular to the surface of (W); an execution specific value group calculating unit (23) for calculating an execution specific value group, which is a specific value group indicating a position where the machining head (11) is actually arranged, based on the ideal specific value group; If the evaluation value indicating the relationship between the current ideal specific value group and the execution specific value group one cycle before is equal to or less than a predetermined reference value, the value group calculation unit (23) calculates the current execution specific value group as the current If the evaluation value of the current ideal specific value group exceeds the reference value, the distance from the processing point is the set distance and the evaluation value is a specific value group in which is equal to the reference value.
(Appendix 2)
In the numerical controller (20) of appendix 1, the ideal specific value group and the execution specific value group may be vectors from the machining point to the position of the machining head (11).

(Appendix 3)
In the numerical controller (20) of Supplementary Note 2, the evaluation value may be an angular difference between the vector of the ideal specific value group and the vector of the execution specific value group.

(Appendix 4)
In the numerical controller (20) of Supplementary Note 3, the reference value is the position of the machining head (11) indicated by the current ideal specific value group and the position of the machining head (11) indicated by the execution specific value group one cycle before. It may be calculated from a value set as the upper limit of the distance.

(Appendix 5)
The numerical controller (20) according to any one of appendices 1 to 4 calculates the movement speed of the machining point when the machining head (11) passes through the position indicated by the execution specific value group, and considers the movement speed of the machining point. An output adjusting section (25) for adjusting the output of the working head (11) may be further provided.

Although the present disclosure has been described in detail above, the present disclosure is not limited to the individual embodiments described above. These embodiments include various additions, replacements, Modification, partial deletion, etc. are possible. Also, these embodiments can be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as an example, and are not limited to these. The same applies when numerical values or formulas are used in the description of the above-described embodiments.

1 Machining System 10 Machining Device 11 Machining Head 12 Work Holder 13 Drive Mechanism 14 Gap Detector 20 Numerical Control Device 21 Movement Controller 22 Ideal Specific Value Group Calculator 23 Execution Specific Value Group Calculator 24 Gap Controller 25 Output Adjuster

Claims (5)

A numerical controller for controlling a machining apparatus comprising a machining head for machining a workpiece, a drive mechanism for relatively moving the workpiece and the machining head, and a gap detector for detecting the distance between the workpiece and the machining head. hand,
a movement control unit that relatively moves the work and the processing head so as to change the position of the processing point on the work to be processed by the processing head;
A specific value group consisting of one or more numerical values for identifying a position offset by a predetermined set distance in a direction perpendicular to the surface of the workpiece from the machining point based on the detection value of the gap detector for each control cycle. An ideal specific value group calculation unit that calculates an ideal specific value group that is
an execution specific value group calculation unit that calculates an execution specific value group, which is a specific value group indicating a position where the machining head is actually arranged, based on the ideal specific value group;
with
The execution specific value group calculation unit calculates the current execution specific value when an evaluation value indicating a relationship between the current ideal specific value group and the execution specific value group one cycle before is equal to or less than a predetermined reference value. The group is the same specific value group as the current ideal specific value group, and when the evaluation value of the current ideal specific value group exceeds the reference value, the current execution specific value group is set from the processing point A numerical controller, wherein the distance is the set distance and the evaluation value is a specific value group equal to the reference value. 2. The numerical controller according to claim 1, wherein said ideal specific value group and said execution specific value group are vectors from said machining point to a position of said machining head. 3. The numerical controller according to claim 2, wherein said evaluation value is an angular difference between a vector of said ideal specific value group and a vector of said execution specific value group. The reference value is calculated from a value set as the upper limit of the distance between the position of the processing head indicated by the current group of ideal specific values and the position of the machining head indicated by the group of execution specific values one cycle before. 4. The numerical controller according to claim 3, wherein Further an output adjustment unit that calculates the moving speed of the processing point when the processing head passes through the position indicated by the execution specific value group, and adjusts the output of the processing head in consideration of the moving speed of the processing point. 5. The numerical controller according to any one of claims 1 to 4, comprising:

Images