CONTOUR ACCURACY MEASURING SYSTEM AND CONTOUR ACCURACY MEASURING METHOD
20200326185 ยท 2020-10-15
Inventors
- Yu-Sheng Tseng (Hsinchu, TW)
- Po-Hsun Wu (Hsinchu, TW)
- Tsung-Yu YANG (Hsinchu, TW)
- Chien-Yi Lee (Hsinchu, TW)
Cpc classification
G05B19/401
PHYSICS
G05B19/402
PHYSICS
G05B19/4155
PHYSICS
G05B19/19
PHYSICS
G01B21/20
PHYSICS
G05B2219/33099
PHYSICS
International classification
Abstract
A contour accuracy measuring system and a contour accuracy measuring method are provided. The contour accuracy measuring system captures location coordinate data of shafts of a machine tool. The location coordinate data are calculated to obtain a first true round trajectory on an inclined plane as reference information. The contour accuracy measuring system then adjusts parameters of the locations of the shafts based on the location coordinate data of the shafts of the reference information to generate a second true round trajectory on the inclined plane, so as to get to know whether the locations of the shafts after the parameters are adjusted comply with a standard. Therefore, the overall measurement process can be speeded up by automatically measuring the parameters and automatically testing an operating status.
Claims
1. A contour accuracy measuring system connectible to a machine tool having a controller and multiple shafts, the contour accuracy measuring system comprising: a capturing module configured for capturing a feedback signal that the controller uses to instruct the shafts to move along a machining route, and calculating locations of the shafts in a machine coordinate system; a transforming module communicatively connected to the capturing module and configured for transforming the locations of the shafts in the machine coordinate system into locations in a workpiece coordination system and vice versa; a processing module communicatively connected to the transforming module and configured for calculating a first true round trajectory of the machining route on an inclined plane presented in the workpiece coordination system as a reference information; and an adjusting module communicatively connected to the processing module and configured for adjusting, based on locations of the shafts transformed from the workpiece coordination system back to the machine coordinate system, parameters of the controller corresponding to the locations of the shafts to generate a target information that includes a second true round trajectory on the inclined plane.
2. The contour accuracy measuring system of claim 1, wherein the processing module calculates the first true round trajectory according to an equation of circle from three points.
3. The contour accuracy measuring system of claim 1, wherein the first true round trajectory and the second true round trajectory have different contours.
4. The contour accuracy measuring system of claim 3, wherein the first true round trajectory and the second true round trajectory have different roundness.
5. The contour accuracy measuring system of claim 1, wherein the reference information includes an estimated roundness of the first true round trajectory.
6. The contour accuracy measuring system of claim 1, wherein the target information includes an estimated roundness of the second true round trajectory.
7. A contour accuracy measuring method applicable to a machine tool having a controller and multiple shafts, the contour accuracy measuring method comprising: capturing, by a capturing module, a feedback signal that the controller uses to instruct the shafts to move along a machining route, and calculating, by the capturing module, locations of the shafts in a machine coordinate system; transforming, by a transforming module, the locations of the shafts in the machine coordinate system to locations in a workpiece coordination system; calculating, by a processing module, a first true round trajectory of the machining route on an inclined plane presented in the workpiece coordination system as a reference information; transforming, by the transforming module, the workpiece coordination system of the reference information into the machine coordinate system and restoring the locations of the shafts in the workpiece coordination system back to the locations in the machine coordinate system; and based on the locations of the shafts of the reference information in the machine coordinate system, adjusting, by an adjusting module, parameters of the controller corresponding to the locations of the shafts to generate a target information that includes a second true round trajectory on the inclined plane.
8. The contour accuracy measuring method of claim 7, wherein the first true round trajectory is calculated according to an equation of a circle from three points.
9. The contour accuracy measuring method of claim 7, wherein the first true round trajectory and the second true round trajectory have different contours.
10. The contour accuracy measuring method of claim 9, wherein the first true round trajectory and the second true round trajectory have different roundness.
11. The contour accuracy measuring method of claim 7, wherein the second true round trajectory and the first true round trajectory are calculated according to the same equation.
12. The contour accuracy measuring method of claim 7, wherein the reference information includes an estimated roundness of the first true round trajectory.
13. The contour accuracy measuring method of claim 7, wherein the target information includes an estimated roundness of the second true round trajectory.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0011] The disclosure can be more fully understood by reading the following detailed description of the embodiments, with reference made to the accompanying drawings, wherein:
[0012]
[0013]
[0014]
[0015]
[0016]
[0017]
[0018]
[0019]
[0020]
[0021]
DETAILED DESCRIPTION
[0022] The following illustrative embodiments are provided to illustrate the disclosure of the present disclosure, these and other advantages and effects can be apparently understood by those in the art after reading the disclosure of this specification.
[0023] It should be appreciated that the structures, proportions, size and the like of the figures in the present application are intended to be used in conjunction with the disclosure of the specification. They are not intended to limit the disclosure and therefore do not represent any substantial technical meanings. Changes or adjustments are considered to be within the scope of the present disclosure, without departing from the scope of the present disclosure. As used herein, the terminologies, such as over, a, and the like, are used to distinguish one element from another, and are not intended to limit the scope of the present application. Changes or adjustments are considered to be within the scope of the present disclosure, without departing from the scope of the present disclosure.
[0024]
[0025] Refer to
[0026] The five-axis machine tool 9 further comprises a base 9b, a supporter 9c and a machining platform 9d. The supporter 9c is erectly disposed on the base 9b. The knife 9a and the machining platform 9d are mounted on the supporter 9c via the shafts 91-95. The first to fifth shafts 91-95 define X-axis, Y-axis, Z-axis, A-axis and C-axis, respectively. The third shaft 93 is movably disposed on the supporter 9c, and moves along a vertical direction (e.g., Z-axis direction Z) with respect to the base 9b. The first shaft 91 is movably disposed on the third shaft 93 and provided with the machining platform 9d, and moves the machining platform 9d along one of directions (e.g., X-axis direction X) of a horizontal plane with respect to the base 9b. The second shaft 92 is movably disposed on the supporter 9c and provided with the knife 9a, and moves the knife 9a along the other one of the directions (e.g., Y-axis direction Y) of the horizontal plane with respect to the base 9b. The fourth shaft 94 is disposed on the first shaft 91 and axially connected to the machining platform 9d, and rotates the machining platform 9d about an axis center of the fourth shaft 94 (e.g., a rotation direction A). The fifth shaft 95 is a rotation plate that self-spins about an axis center of the fifth shaft 95 with respect to the machining platform 9d (e.g., a rotation direction C), and is mounted on the machining platform 9d for carrying a workpiece (not shown). Therefore, the location of the knife 9a with respect to the workpiece (i.e., the fifth shaft 95) can be inferred from the movement of the first to fifth shafts 91-95.
[0027] The capturing module 10 is configured for capturing a feedback signal of the controller 90 corresponding to a machining route of the first to fifth shafts 91-95 (or the knife 9a), and calculating locations of the first to fifth shafts 91-95 in a machine coordinate system.
[0028] In an embodiment, the machine coordinate system is defined with the base 9b as a reference plane, such as a coordinate definition with an origin Om (Xm, Ym, Zm) shown in
[0029] The transforming module 11 is communicatively connected to the capturing module 10 (in a wired or wireless manner), and transforms locations of the first to fifth shafts 91-95 in the machine coordinate system into locations in the workpiece coordination system and vice versa.
[0030] In an embodiment, the workpiece coordination system is defined to divide the machine tool 9 into a plurality of coordinate systems to describe the relative displacement and gesture between the shafts of the machine tool. In an embodiment, the workpiece acts as an initial coordinate which defines the locations of the workpiece and the fifth shaft 95, a fifth sub-coordinate is a relative location relation of the fifth shaft 95 (the rotation plate) and the machining platform 9d, a fourth sub-coordinate is a relative location relation of the fourth shaft 94 and the machining platform 9d, a third sub-coordinate is a relative location relation of the third shaft 93 and the first shaft 91, a second sub-coordinate is a relative location relation of the second shaft 92 and the supporter 9c, a first sub-coordinate is a location relation of the first shaft 91 and the fourth shaft 94, a vertical coordinate is a relative location relation of the supporter 9c and the third shaft 93, a base coordinate is relative location relation of the base 9b and the supporter 9c, a knife coordinate is a relative location relation of the knife 9a and the second shaft 92, etc.
[0031] The processing module 12 is communicatively connected to (in a wired or wireless manner) the transforming module 11, and calculates a first true round trajectory of the machining route on an inclined plane presented in the workpiece coordination system as reference information.
[0032] In an embodiment, the processing module 12 calculates the first true round trajectory on the inclined plane according to an equation of a circle from three points.
[0033] The reference information is a measurement result that comprises an estimated roundness of the first true round trajectory, which is displayed on a display of the electronic device 1a.
[0034] The adjusting module 13 is communicatively connected to (in a wired or wireless manner) the processing module 12, transforms the locations in the workpiece coordination system back into the locations in the machine coordinate system based on the first to fifth shafts 91-95 of the reference information, and adjusts the parameters of the controller 90 corresponding to the locations of the first to fifth shafts 91-95 to generate the target information, which comprises a second true round trajectory on the inclined plane.
[0035] In an embodiment, the first true round trajectory and the second true round trajectory have different contours. In another embodiment, the first true round trajectory and the second true round trajectory have different roundness.
[0036] The target information is an adjusting result that comprises an estimated roundness of the second true round trajectory, which is displayed on the display of the electronic device 1a.
[0037]
[0038] In step S21, a user actuates the machine tool 9 and the contour accuracy measuring system 1 (or the electronic device 1a), and inputs parameters to the controller 90 to enable a servo motor to actuate the first to fifth shafts 91-95 to enable the knife 9a to run idle before a machining process is performed (i.e., no workpiece being on the fifth shaft 95); the capturing module 10 of the contour accuracy measuring system 1 (or the electronic device 1a) captures via a communication transmission mechanism (e.g., a network) a feedback signal of the controller 90 (or the servo motor) corresponding to a machining route of the knife 9a (or the movements of first to fifth shafts 91-95); and the capturing module 10 calculates locations of the first to fifth shafts 91-95 in the machine coordinate system (e.g., first coordinate data of a moving route).
[0039] In an embodiment, the capturing module 10 captures data by direct internal transmission (e.g., the machine tool 9 being arranged with the contour accuracy measuring system 1 or the electronic device 1a), an application program interface (e.g., for obtaining internal information of a digital controller of the machine tool 9), a programmable controller (e.g., a programmable logic controller (PLC)) for transmitting and storing internal and external signals of the controller 90, or direct transmission of an external device (e.g., an encoder that transmits coordinate signals, an optical scale that transmits coordinate signals, or a data capturing card that transmits coordinates, NC code column numbers or G code types).
[0040] In the operation of the machine tool 9, the contour accuracy measuring system 1 can obtain and record coordinate data of a moving route of the knife 9a of the machine tool 9 from various sources, such as a position controller and a speed controller of the controller 90 of the machine tool 9, an encoder on a servo motor of the machine tool 9, or an optical scale on the machining platform 9d.
[0041] In step S22, a first coordinate transforming process is performed, in which the transforming module 11 of the electronic device 1 transforms the locations of the first to fifth shafts 91-95 in the machine coordinate system into the locations in workpiece coordination system.
[0042] In an embodiment, the transforming module 11 transforms, based on Forward Kinematics, the actual locations of the first to fifth shafts 91-95 from the locations in the machine coordinate system to the locations in the workpiece coordination system (e.g. second coordinate data of a moving route).
[0043] In step S23, the electronic device 1a employs the processing module 12 to perform a calculation process to calculate a first true round trajectory S1 of the machining route of the knife 9a (or movements of the first to fifth shafts 91-95) on an inclined plane E presented in the workpiece coordination system, such as a knife coordinate (O.sub.T, X.sub.T, Y.sub.T, Z.sub.T) shown in
[0044] In an embodiment, the calculation process is a contour accuracy estimating process, in which an average central point is obtained from the information of the transformed workpiece coordination system (e.g., the second coordinate data of a moving route) according to an equation of a circle from three points, and a difference between a maximal radius and a minimum radius is calculated based on the central point. As shown in
X.sub.O=X.sub.m1+K.sub.11=X.sub.m2+K.sub.22;
Y.sub.O=Y.sub.m1+K.sub.11=Y.sub.m2+K.sub.22; and
Z.sub.O=Z.sub.m1+K.sub.11=Z.sub.m2+K.sub.22,
where (X.sub.m1, Y.sub.m1, Z.sub.m1) represents the coordinate of a middle point ml of the first line segment ab, (X.sub.m2, Y.sub.m2, Z.sub.m2) represents the coordinate of a middle point m2 of second line segment bc, and .sub.1, .sub.1, .sub.1, .sub.2, .sub.2 and .sub.2 are unit vectors of the perpendicular bisectors.
[0045] The coordinates of the middle points m.sub.1 and m.sub.2 are calculated as follows:
m.sub.1=(X.sub.a+X.sub.bY.sub.a+Y.sub.bZ.sub.a+Z.sub.b); and
m.sub.2=(X.sub.b+X.sub.cY.sub.b+Y.sub.cZ.sub.b+Z.sub.c).
[0046] The maximal radius R.sub.1 and the minimum radius R.sub.2 can be inferred as follows:
R.sub.1=[X.sub.m1(i)+Y.sub.m1(j)+Z.sub.m1(k)]+K.sub.1[.sub.1(i)+.sub.1(j)+.sub.1(k)]; and
R.sub.2=[X.sub.m2(i)+Y.sub.m2(j)+Z.sub.m2(k)]+K.sub.2[.sub.2(i)+.sub.2(j)+.sub.2(k)],
where i, j and k represent three dimensions of a vector.
[0047] The central points K.sub.1 and K.sub.2 are calculated as follows:
K.sub.1=[.sub.2(X.sub.m2X.sub.m1).sub.2(Y.sub.m1Y.sub.m2)]/(.sub.1.sub.2.sub.2.sub.1); and
K.sub.2=(X.sub.m1+K.sub.11X.sub.m2)/.sub.2.
[0048] In step S24, a second coordinate transforming process is performed, in which the transforming module 11 of the electronic device 1a transforms the workpiece coordination system of the reference information into the machine coordinate system, via, for example, Inverse Kinematics, allowing the locations of the first to fifth shafts 91-95 in the workpiece coordination system to be restored to the locations in the machine coordinate system (e.g., third coordinate data of a moving route).
[0049] In step S25, the adjusting module 13 of the electronic device 1a synchronously adjusts the parameters of the controller 90 corresponding to the locations of the first to fifth shafts 91-95 according to the locations of the first to fifth shafts 91-95 of the reference information in the machine coordinate system to generate target information (e.g., fourth coordinate data of a moving route). In an embodiment, the target information comprises the second true round trajectory S2 on the inclined plane E, which can be displayed on the electronic device 1a, as shown in
[0050] In an embodiment, since the controller 90 synchronously adjusts the locations of the first to fifth shafts 91-95, allowing the capturing module 10 of the electronic device 1a (the contour accuracy measuring system 1) to capture signals of the controller 90 that are used to adjust the servo motor of the first to fifth shafts 91-95 again and calculate an estimated roundness (e.g., 8.1 um shown in
[0051] As shown in
[0052] For a control loop, the most important condition is the accuracy of the machine. Therefore, the control loop is designed to be a location close-loop control. For a driver and a control motor (such as the AC servo motor 5a shown in
[0053] In
[0054]
[0055]
[0056] The roundness and the controller 90 are adjusted based on the following steps.
[0057] Step (1): Based on a machine machining result, the controller 90 is measured and determined whether it needs be adjusted. If so, proceed to step (2).
[0058] Step (2): The signals of the machining result are analyzed, to determine whether the variations of the five moving shafts (the first to fifth shafts 91-95) in the location diagram have the same trends (e.g., the curves L91-L95 shown in
[0059] Step (3): After K.sub.pp is adjusted, the speed data are analyzed (e.g., as shown in
[0060] Step (4): The machining process is performed again, to ensure that the adjustment of steps (1) to (3) has been input to the controller 90 successfully.
[0061] Therefore, the contour accuracy measuring method performed by the contour accuracy measuring system 1 according to the present disclosure keeps on calculating the maximum and minimum errors of the roundness (i.e. the smaller estimated roundness are better) on the inclined plane E based on a vector algorithm with respect to stimulation of the pin location of the knife 9a, to determine whether the parameters of locations of the first to fifth shafts 91-95 in the machine coordinate system meet the demands, and estimate the effect of the parameters of the servo motor of the machine tool 9 on the synchronously moving contour accuracy of multiple shafts of a machine (e.g., the second true round trajectory S2 on the inclined plane E shown in
[0062] The synchronously moving parameters of multiple shafts of a machine can be adjusted, and the speed gains, speed integration time constants and other parameters can be adjusted based on the established quantification data table.
[0063] In the contour accuracy measuring system 1 and the contour accuracy measuring method according to the present disclosure, coordination data captured by the capturing module 10 are transmitted via the transforming module 11 to the processing module 12 to calculate the reference information, and the first to fifth shafts 91-95 of the machine tool 9 are operated via the reference information in real time to get to know whether the locations of the first to fifth shafts 91-95 after the parameters are adjusted meet a standard, so that the cutting accuracy of the knife 9a can be measured in real time. Compared with the prior art, the contour accuracy measuring system 1 (the electronic device 1a) according to the present disclosure allows a user to measure parameters and test operating states automatically and instantly know the parameters (or machining accuracy) that the knife 9a of the machine tool 9 needs to comply with a standard. Therefore, the overall measuring process is fast, the workpiece used for testing is not consumed, and the measurement cost is reduced.
[0064] In addition to the above-mentioned five-axis machining tool, the contour accuracy measuring system 1 and the contour accuracy measuring method according to the present disclosure can also be applied to other machine tools.
[0065] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.