Numerical controller
The numerical control device calculates ideal and performs the determination value group, adjusts the position of the machining head to maintain a constant offset, solves the vibration problem caused by the change in the normal direction of the workpiece surface and achieves high-precision machining stability.
Patent Information
- Application Number
- CN202280102411.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-16
- Publication Date
- 2025-07-22
AI Technical Summary
When the normal direction at the machining point on the workpiece surface changes sharply, abnormal vibrations are caused by the processing device, which is difficult to effectively suppress in the prior art.
The ideal value group is calculated by the numerical control device and the value group is executed. The gap detector is used to detect the distance between the workpiece and the processing head, and the position of the processing head is adjusted to maintain a constant offset distance, so as to suppress the rapid movement of the processing head and prevent vibration.
Accuracy and stability during workpiece surface processing are achieved, abnormal vibration of the processing device is suppressed, and processing quality is ensured.
Smart Images
Figure CN120359475A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a numerical control device. Background Art
[0002] Generally, when the processing head and the workpiece are relatively moved to process the workpiece, it is required to offset the processing head from the workpiece by a certain distance. As an example, in laser processing, it is desired to maintain the offset distance of the processing head relatively strictly corresponding to the focal length of the laser. In order to precisely maintain the offset of the processing head at a constant distance, it has been proposed to detect the distance between the processing head and the workpiece by a detector provided on the processing head, and adjust the position of the processing head so as to keep the distance between the processing head and the workpiece constant (for example, refer to Patent Document 1).
[0003] Prior Art Documents
[0004] Patent Documents
[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-192970 Summary of the Invention
[0006] Problems to be Solved by the Invention
[0007] Preferably, the offset of the processing head is performed in the normal direction at the processing point on the surface of the workpiece. Depending on the surface shape of the workpiece, the normal direction at the processing point may change abruptly, which may cause abnormal vibration of the processing device.
[0008] Means for Solving the Problems
[0009] A numerical control device according to an aspect of the present disclosure controls a machining device, the machining device including: a machining head that machines a workpiece; a drive mechanism that relatively moves the workpiece and the machining head; and a gap detector that detects the distance between the workpiece and the machining head. The numerical control device includes: a movement control unit that relatively moves the workpiece and the machining head so that the position of a machining point on the workpiece machined by the machining head changes; an ideal determination value set calculation unit that calculates, for each control cycle, an ideal determination value set based on the detection value of the gap detector, the ideal determination value set being a determination value set composed of one or more numerical values that determine a position offset by a predetermined set distance in a direction perpendicular to the surface of the workpiece from the machining point; and an execution determination value set calculation unit that calculates an execution determination value set based on the ideal determination value set, the execution determination value set being a determination value set indicating the position where the machining head is actually disposed. When an evaluation value indicating the relationship between the current ideal determination value set and the execution determination value set one cycle before is equal to or less than a predetermined reference value, the execution determination value set calculation unit sets the current execution determination value set to be the same as the current ideal determination value set, and when the evaluation value of the current ideal determination value set exceeds the reference value, the execution determination value set calculation unit sets the current execution determination value set to be a determination value set having a distance of the set distance from the machining point and an evaluation value equal to the reference value. Description of the Drawings
[0010] Figure 1 is a schematic structural diagram of a machining system including a numerical control device according to an embodiment of the present disclosure.
[0011] Figure 2 is a schematic diagram showing Figure 1 the relationship between the ideal determination value set and the execution determination value set calculated by the numerical control device. Detailed Description of the Embodiment
[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Figure 1 is a schematic structural diagram of a machining system 1 including a numerical control device 20 according to an embodiment of the present disclosure. The machining system 1 includes a machining device 10 and a numerical control device 20 that controls the machining device 10.
[0013] The machining device 10 includes: a machining head 11 that machines a workpiece W; a workpiece holding unit 12 that holds the workpiece W; a drive mechanism 13 that relatively moves the workpiece W held by the workpiece holding unit 12 and the machining head 11; and a gap detector 14 that detects the distance between the workpiece W and the machining head 11.
[0014] The processing head 11 can be, for example, a laser head that irradiates a workpiece W with a laser, a cutting head having a rotary tool, etc. The output of the processing head 11, such as the intensity of the laser, the torque of the rotary tool, etc., is preferably configured to be adjustable by the numerical control device 20.
[0015] The workpiece holding part 12 only needs to be able to hold the workpiece W, and can be configured to have a workbench, a chuck, etc., for example. In the illustrated embodiment, it is desirable for the workpiece holding part 12 to have a chuck that holds the workpiece W and rotates it by the drive mechanism 13.
[0016] The drive mechanism 13 is configured to be able to relatively move the processing head 11 and the workpiece W so that the processing point for machining the workpiece W by the processing head 11 moves. In the present embodiment, the drive mechanism 13 includes: a rotational drive mechanism 131 that rotates the workpiece W by rotating the workpiece holding part 12 and changes the position of the processing point on the workpiece W facing the processing head 11. In the illustrated embodiment, the rotational drive mechanism 131 rotates the workpiece W held by the workpiece holding part 12 about an axis C perpendicular to the paper surface. In addition, the drive mechanism 13 is configured to be able to adjust the distance between the processing head 11 and the workpiece W. In the present embodiment, the drive mechanism 13 includes: a rectangular coordinate system drive mechanism 132 that has a plurality of drive axes for changing the position and orientation of the processing head 11. In addition, the drive mechanism 13 is not limited to these structures, and can be any structure such as a structure including an articulated robot that moves the processing head 11 or the workpiece holding part 12, etc.
[0017] In order to accurately measure the distance between the processing head 11 and the workpiece W, the gap detector 14 is preferably disposed on the processing head 11. As the gap detector 14, an electrostatic capacitance sensor, a laser sensor, an ultrasonic sensor, etc. can be used, for example.
[0018] The numerical control device 20 has a memory, a processor (CPU), an input / output interface, etc., and can be implemented by one or more computer devices that execute an appropriate control program. The structural elements of the numerical control device 20 described below are classified according to the functions (actions of the processor) of the numerical control device 20, and may not be structural elements that can be clearly distinguished in the physical structure and program structure.
[0019] The numerical control device 20 includes a movement control part 21, an ideal determination value set calculation part 22, an execution determination value set calculation part 23, a gap control part 24, and an output adjustment part 25.
[0020] The movement control unit 21 moves the workpiece W relative to the processing head 11 to change the position of the processing point on the workpiece W processed by the processing head 11. In the present embodiment, it is desirable that the movement control unit 21 rotates the chuck of the workpiece holding unit 12 to rotate the workpiece W around the axis C, thereby moving the position of the processing point facing the processing head 11. However, the movement control unit 21 may also move the processing point by operating the processing device 10 in such a manner that the position of at least one of the workpiece W and the processing head 11 changes.
[0021] For each control cycle, the ideal determination value group calculation unit 22 calculates an ideal determination value group based on the detection value of the gap detector 14. The ideal determination value group is a determination value group composed of one or more numerical values that determine the position of the processing head 11 at a position offset by a predetermined set distance in a direction perpendicular to the surface of the workpiece W from the processing point. The position of the processing head 11 may be set as the position of the front end of the main body other than tools, etc. In addition, the "determination value group" is a set of one or more numerical values representing the position of the processing head 11, and may be a single angle, vector, etc. based on the position of the processing point, or coordinates in a non-moving coordinate system, etc. In order to easily grasp the movement of the processing head 11 in one cycle of the control cycle, the "determination value group" is preferably a vector starting from the position of the processing point.
[0022] The ideal determination value group calculation unit 22 calculates the orientation at the processing point on the surface of the workpiece W in consideration of the movements of the processing head 11 and the workpiece W. Specifically, the ideal determination value group calculation unit 22 can determine where the processing point one cycle ago is currently located based on the detection value of the gap detector 14 one cycle ago, the detection value of the gap detector 14 this time, and the movement amounts of the processing head 11 and the workpiece W from one cycle ago to the present. And the ideal determination value group calculation unit 22 can calculate the position where the processing point is offset by a predetermined set distance with the slope of the straight line connecting the processing point one cycle ago and the current processing point as the surface direction of the workpiece W at the current processing point.
[0023] Based on the ideal determination value group, the execution determination value group calculation unit 23 calculates a determination value group representing the position where the processing head 11 is actually arranged, that is, the execution determination value group. When the position represented by the current ideal determination value group is significantly far from the position represented by the execution determination value group one cycle ago, the execution determination value group calculation unit 23 sets an execution determination value group at a position closer to the position represented by the execution determination value group one cycle ago than the position represented by the current ideal determination value group. Thereby, the abrupt movement of the processing head 11 is suppressed, and abnormal vibration of the processing device 10 is prevented.
[0024] Specifically, the execution determination value group calculation unit 23 is configured to set the current execution determination value group to the same determination value group as the current ideal determination value group when the evaluation value indicating the relationship between the current ideal determination value group and the execution determination value group one cycle before is equal to or less than a predetermined reference value, and set the current execution determination value group to a determination value group whose distance from the machining point is a set distance and whose evaluation value is equal to the reference value when the evaluation value of the current ideal determination value group exceeds the reference value.
[0025] The "evaluation value" can be relatively simply set as the angular difference between the vector of the ideal determination value group and the vector of the execution determination value group, the magnitude of the difference vector between the vector of the ideal determination value group and the vector of the execution determination value group, the distance between the position indicated by the ideal determination value group and the position indicated by the execution determination value group, etc. Among them, if the angular difference of the vectors is calculated as the evaluation value, the movement amount of the machining head 11 can be grasped relatively easily and accurately. In this case, the reference value is the upper limit value of the angular difference between the vector of the ideal determination value group and the vector of the execution determination value group. However, in order to make it easier for the user to understand when setting the reference value, it can also be calculated based on the value set by the user according to the upper limit value of the distance between the position of the machining head 11 indicated by the current ideal determination value group and the position of the machining head 11 indicated by the execution determination value group one cycle before.
[0026] While referring to Figure 2 , an example of the calculation method of the determination value group based on the execution determination value group calculation unit 23, where the distance from the machining point is a set distance and the angular difference of the vector as the evaluation value is equal to the reference value, will be described in more detail when the determination value group is a three-dimensional vector from the machining point to the position where the machining head 11 is arranged. Figure 2 An example showing that the machining point moves due to the rotation of the workpiece W, and the orientation of the surface of the workpiece W at the machining point and the moving speed of the machining point change because the workpiece W has corners.
[0027] In Figure 2 , the vector of the current ideal determination value group is set as V1i, the vector of the execution determination value group that coincides with the ideal determination value group one cycle before is set as V0e, and the vector of the newly set execution determination value group is set as V1e. Subscripts x, y, and z are used to distinguish the respective components of each vector in the X, Y, and Z directions. In addition, the reference value of the angular difference of the vectors is set as θ.
[0028] The vector V1e of the new execution determination value group is calculated by rotating the vector V0e of the execution determination value group one cycle before by an angle θ serving as the reference value around an axis perpendicular to both the vector V0e and the vector V1i of the current ideal determination value group. Therefore, first, as shown in the following mathematical formula 1, the vector ver that becomes the central axis for rotating the vector V0e is calculated as the outer product of the vector V0e and the vector V1i.
[0029] [Mathematical formula 1]
[0030]
[0031] Next, as shown in the following Mathematical formula 2, calculate the magnitude norm of the vector ver, and as shown in the following Mathematical formula 3, convert each component of the vector ver into a unit vector Vu by dividing the magnitude of the vector by norm.
[0032] [Mathematical formula 2]
[0033]
[0034] [Mathematical formula 3]
[0035]
[0036] Using this unit vector Vu, as shown in the following Mathematical formula 4, the vector V1e of the execution determination value group in the current control cycle can be calculated by rotating the vector V0e by the angle θ.
[0037] [Mathematical formula 4]
[0038]
[0039] In addition, when a reference value is given as the upper limit value D of the distance between the position of the machining head 11 represented by the vector V1i of the current ideal determination value group (the end point of the vector V1i) and the position of the machining head 11 represented by the vector V0e of the execution determination value group in the previous cycle (the end point of the vector V0e), when the set distance is set to G, the angular difference θ of the vector can be represented by the following Mathematical formula 5.
[0040] [Mathematical formula 5]
[0041]
[0042] The gap control unit 24 disposes the machining head 11 at the position indicated by the current execution determination value group. More specifically, the gap control unit 24 calculates the driving amount of each axis of the driving mechanism 13 required to dispose the machining head 11 at the position indicated by the current execution determination value group, and controls the driving mechanism 13.
[0043] The output adjustment unit 25 calculates the moving speed of the machining point when the machining head 11 executes the positions shown in the set of determined values, 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 machining head, such as the intensity of the laser, when the moving speed of the machining point is low, and increases the output of the machining head when the moving speed of the machining point is high. Thereby, the machining degree of the workpiece W at the machining point can be made uniform.
[0044] As described above, the machining system 1 equipped with the numerical control device 20 can suppress the moving amount of the machining head 11 in one control cycle, and thus can suppress vibration to perform accurate machining.
[0045] Regarding the above-described embodiments and modification examples, the following supplementary notes are further disclosed.
[0046] (Supplementary Note 1)
[0047] A numerical control device 20 that controls a machining device 10, the machining device 10 including: a machining head 11 that machines a workpiece W; a drive mechanism 13 that relatively moves the workpiece W and the machining head 11; a gap detector 14 that detects the distance between the workpiece W and the machining head 11, wherein the numerical control device 20 includes: a movement control unit 21 that relatively moves the workpiece W and the machining head 11 so that the position of the machining point on the workpiece machined by the machining head 11 changes; an ideal set of determined values calculation unit 22 that calculates, for each control cycle, an ideal set of determined values based on the detection value of the gap detector 14, the ideal set of determined values being a set of one or more numerical values that determine a position offset by a predetermined set distance from the machining point in a direction perpendicular to the surface of the workpiece W; an execution set of determined values calculation unit 23 that calculates an execution set of determined values based on the ideal set of determined values, the execution set of determined values being a set of determined values that represents the actual position where the machining head 11 is arranged, and the execution set of determined values calculation unit 23 sets the current execution set of determined values to be the same as the current ideal set of determined values when the evaluation value representing the relationship between the current ideal set of determined values and the execution set of determined values in the previous cycle is equal to or less than a predetermined reference value, and sets the current execution set of determined values to be a set of determined values with a distance of the set distance from the machining point and an evaluation value equal to the reference value when the evaluation value of the current ideal set of determined values exceeds the reference value.
[0048] (Supplementary Note 2)
[0049] Alternatively, in the numerical control device 20 of Supplementary Note 1, the ideal set of determined values and the execution set of determined values are vectors from the machining point to the position of the machining head 11.
[0050] (Supplementary Note 3)
[0051] Alternatively, in the numerical control device 20 of Supplementary Note 2, the evaluation value is the angular difference between the vector of the ideal determination value group and the vector of the execution determination value group.
[0052] (Supplementary Note 4)
[0053] Alternatively, in the numerical control device 20 of Supplementary Note 3, the reference value is calculated based on the upper limit value of the distance between the position of the processing head 11 represented by the currently set ideal determination value group and the position of the processing head 11 represented by the execution determination value group one cycle ago.
[0054] (Supplementary Note 5)
[0055] Alternatively, in the numerical control device 20 according to any one of Supplementary Notes 1 to 4, it further includes: an output adjustment unit 25 that calculates the moving speed of the machining point when the processing head 11 passes through the position represented by the execution determination value group, and adjusts the output of the processing head 11 in consideration of the moving speed of the machining point.
[0056] The above has described the present disclosure in detail, but the present disclosure is not limited to the above-described respective embodiments. These embodiments can be subjected to various additions, replacements, changes, partial deletions, etc. within the scope not departing from the gist of the present disclosure, or within the scope not departing from the gist of the present disclosure derived from the content described in the scope of patent protection requested and its equivalents. In addition, these embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each action and the order of each process are shown as an example and are not limited thereto. In addition, the same applies to the case where numerical values or mathematical formulas are used in the description of the above-described embodiments.
[0057] Description of Reference Numerals
[0058] 1 Machining system,
[0059] 10 Machining device,
[0060] 11 Processing head,
[0061] 12 Workpiece holding part,
[0062] 13 Driving mechanism,
[0063] 14 Gap detector,
[0064] 20 Numerical control device,
[0065] 21 Movement control part,
[0066] 22 Ideal determination value group calculation part,
[0067] 23 Execution determination value group calculation part,
[0068] 24 Gap control part,
[0069] 25 Output adjustment unit.
Claims
1. A numerical control device for controlling a processing device, the processing device comprising: a processing head for processing a workpiece; a drive mechanism for relatively moving the workpiece and the processing head; a gap detector for detecting the distance between the workpiece and the processing head, characterized in that the numerical control device comprises: a movement control unit for relatively moving the workpiece and the processing head so that the position of a processing point on the workpiece processed by the processing head changes; an ideal determination value group calculation unit for calculating, for each control cycle, an ideal determination value group based on the detection value of the gap detector, the ideal determination value group being a determination value group composed of one or more numerical values for determining a position offset by a predetermined set distance in a direction perpendicular to the surface of the workpiece from the processing point; and an execution determination value group calculation unit for calculating, based on the ideal determination value group, an execution determination value group, the execution determination value group being a determination value group representing the position where the processing head is actually arranged, the execution determination value group calculation unit sets the current execution determination value group to be the same as the current ideal determination value group when an evaluation value representing the relationship between the current ideal determination value group and the execution determination value group one cycle before is equal to or less than a predetermined reference value, and sets the current execution determination value group to be a determination value group having a distance of the set distance from the processing point and an evaluation value equal to the reference value when the evaluation value of the current ideal determination value group exceeds the reference value.
2. The numerical control device according to claim 1, characterized in that the ideal determination value group and the execution determination value group are vectors from the processing point to the position of the processing head.
3. The numerical control device according to claim 2, characterized in that the evaluation value is the angular difference between the vector of the ideal determination value group and the vector of the execution determination value group.
4. The numerical control device according to claim 3, characterized in that the reference value is calculated according to a value set as an upper limit value of the distance between the position of the processing head represented by the current ideal determination value group and the position of the processing head represented by the execution determination value group one cycle before.
5. The numerical control device according to any one of claims 1-4, characterized in that the numerical control device further comprises: an output adjustment unit for calculating the moving speed of the processing point when the processing head passes through the position represented by the execution determination value group, and adjusting the output of the processing head in consideration of the moving speed of the processing point.
Citation Information
Patent Citations
Laser processing apparatus and laser processing method
JP2017192970A