Calibration method and device for rotating shaft in five-axis machine tool and medium

Abstract

Embodiments of the present application disclose a kind of calibration method, device and medium for rotating shaft in five-axis machine tool;The method comprises: in the case of fixing other rotating shafts except the rotating shaft to be calibrated, fitting according to the vertex coordinate values of at least two different standard balls at a plurality of first rotation angle positions, obtaining the first space circle model corresponding to each standard ball and the first space circle model parameter;Based on the first space circle model, the spherical point coordinates of the standard ball at a plurality of second rotation angle positions are collected, and the second space circle model of each standard ball according to the rotating shaft to be calibrated is fitted according to the collected spherical point coordinates;According to the second space circle model corresponding to each standard ball, the axis direction around the rotating shaft to be calibrated is obtained, and the characteristic quantity for representing the end of fitting is recorded;When the characteristic quantity does not meet the set fitting end condition, continue to collect the spherical point coordinates of the standard ball at a plurality of second rotation angle positions.

Description

Technical Field

[0001] The embodiments of the present invention relate to precision machining control and measurement technology, and in particular to a calibration method, device and medium for rotary axes in a five-axis machine tool. Background Technology

[0002] Compared to traditional three-axis machine tools, five-axis machine tools add two rotational axes, or rotary axes, to the three translational axes. In some examples, these two rotary axes are designated as the A-axis and the C-axis; the A-axis is defined as the rotation axis with the X-axis as its axis of rotation, and the C-axis is defined as the rotation axis with the Z-axis as its axis of rotation. Based on these two rotary axes, five-axis machine tools can machine three-dimensional parts with complex curved surfaces, offering a significant advantage over traditional three-axis machine tools with only three translational axes.

[0003] During the long-term use of five-axis machine tools, due to unstable factors such as machining vibration, environmental conditions, and improper operation, deviations may occur between the actual zero point and the actual axis of rotation of the rotary axis and the standard zero point and axis of rotation. This directly affects the consistency of machining accuracy. Therefore, it is necessary to calibrate the A / C axis regularly or irregularly during use to reduce deviations and improve the consistency of machining accuracy.

[0004] Conventional A / C axis calibration methods rely on calibration boards, which require manual collection of a large number of data points on the calibration board. As a result, the calibration efficiency is low and the accuracy is unstable. Summary of the Invention

[0005] In view of this, the present invention aims to provide a calibration method, apparatus and medium for the rotary axes of a five-axis machine tool; which can improve the calibration efficiency of the rotary axes (A / C axes) of the machine tool and achieve stable calibration of the rotary axes (A / C axes) of the machine tool.

[0006] The technical solution of this invention is implemented as follows:

[0007] In a first aspect, embodiments of the present invention provide a calibration method for rotary axes in a five-axis machine tool, the method comprising:

[0008] With other rotation axes fixed except for the rotation axis to be calibrated, the vertex coordinates of at least two standard spheres of different heights at multiple first rotation angle positions are fitted to obtain a first spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated, and the parameters of the first spatial circle model corresponding to each standard sphere are obtained.

[0009] Based on the first spatial circle model, the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions are collected, and the second spatial circle model of each standard sphere rotating according to the collected coordinates of the spherical points of the standard sphere at multiple second rotation angle positions is obtained by fitting.

[0010] The direction of the axis around which the rotation axis to be calibrated is located is obtained based on the second spatial circle model corresponding to each standard sphere, and the characterization quantity used to characterize the end of the fitting is recorded.

[0011] If the feature quantity does not meet the set fitting termination condition, continue to collect the spherical point coordinates of the standard sphere at multiple second rotation angle positions until the feature quantity obtained in the fitting conclusion step meets the set fitting termination condition.

[0012] Secondly, embodiments of the present invention provide a calibration device for rotary axes in a five-axis machine tool, the device comprising: a first fitting section, a data acquisition section, a second fitting section, an acquisition section, and a determination section; wherein,

[0013] The first fitting part is configured to, under the condition of fixing other rotation axes except the rotation axis to be calibrated, fit the vertex coordinate values ​​of at least two standard spheres of different heights at multiple first rotation angle positions to obtain a first spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated, and obtain the first spatial circle model parameters corresponding to each standard sphere.

[0014] The acquisition section is configured to acquire the coordinates of spherical points of a standard sphere at multiple second rotation angle positions based on the first spatial circle model.

[0015] The second fitting part is configured to fit the spherical point coordinates of the collected standard spheres at multiple second rotation angle positions to obtain a second spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated.

[0016] The acquisition part is configured to obtain the direction of the axis around which the rotation axis to be calibrated revolves based on the second spatial circle model corresponding to each standard sphere, and record the characterization quantity used to characterize the end of the fitting.

[0017] The determination section is configured to continue collecting the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions when the feature quantity does not meet the set fitting termination condition, until the feature quantity obtained in the fitting conclusion step meets the set fitting termination condition.

[0018] Thirdly, embodiments of the present invention provide a computing device, including: a communication interface, a memory, and a processor; the various components are coupled together via a bus system; wherein,

[0019] The communication interface is used for receiving and sending signals during the process of sending and receiving information with other external network elements;

[0020] The memory is used to store computer programs that can run on the processor;

[0021] The processor is configured to, when running the computer program, execute the steps of the calibration method for rotary axes in a five-axis machine tool as described in the first aspect.

[0022] Fourthly, embodiments of the present invention provide a computer storage medium storing a calibration program for a rotary axis in a five-axis machine tool, wherein when the calibration program for the rotary axis in a five-axis machine tool is executed by at least one processor, the calibration program for the rotary axis in a five-axis machine tool implements the steps of the calibration method for the rotary axis in a five-axis machine tool described in the first aspect.

[0023] This invention provides a calibration method, device, and medium for rotary axes in a five-axis machine tool. Taking into account the characteristics of a dual-rotor five-axis machine tool, it collects position data of at least two standard spheres with varying heights at different rotary axis (A / C axis) angles. Then, it fits the coordinates of the sphere centers. Finally, by combining the fitted sphere center coordinates with the motion mathematical model of the rotary axis (A / C axis), it calculates the position and direction of the rotary axis (A / C axis). This enables rapid and stable calibration of the rotary axis (A / C axis), improving the calibration efficiency of the machine tool's rotary axes (A / C axis) and achieving stable calibration. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a five-axis machine tool with respect to the A / C axes provided in an embodiment of the present invention;

[0025] Figure 2 A schematic diagram illustrating the setting of a standard ball according to an embodiment of the present invention;

[0026] Figure 3 A schematic flowchart of a calibration method for rotary axes in a five-axis machine tool provided by an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of layered acquisition of spherical coordinates provided in an embodiment of the present invention;

[0028] Figure 5 This is a calibration diagram for the A-axis provided in an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the interference region provided in an embodiment of the present invention;

[0030] Figure 7 This is a schematic diagram of the computational interference region provided in an embodiment of the present invention;

[0031] Figure 8 (a) and (b) are schematic diagrams of the axial directions around the C-axis and A-axis provided in the embodiments of the present invention, respectively;

[0032] Figure 9 A schematic diagram of a calibration device for a rotary axis in a five-axis machine tool, provided by an embodiment of the present invention;

[0033] Figure 10 This is a schematic diagram of the hardware structure of a computing device provided in an embodiment of the present invention. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0035] Figure 1 A schematic diagram of a five-axis machine tool with respect to the A / C axes is shown, as follows: Figure 1 As shown in the upper left, the translational axes of the machine tool are the X, Y, and Z axes. The machining table is used to support the workpiece to be processed and is mounted on a support. By controlling the support, the workpiece on the machining table can rotate along the A and C axes. Based on this understanding... Figure 1 The shown support can be connected to a CNC device, thereby enabling control of the support's movement. Figure 1 Taking the A / C axis diagram as an example, the C axis rotates around the Z axis, and the A axis rotates around the X axis. Therefore, in the subsequent disclosures of this invention, both the A axis and the C axis will be referred to as rotation axes. These two rotation axes can rotate simultaneously to participate in machining, thereby enabling the machining of three-dimensional parts with complex curved surfaces.

[0036] Understandably, since the technical solution of this invention only calibrates the A / C axes, other components in a conventional five-axis machine tool are not calibrated. Figure 1 As shown in the image.

[0037] based on Figure 1 The diagram shown below illustrates the A / C axis. For the purpose of calibrating the A / C axis, as... Figure 2As shown, in this embodiment of the invention, two high-precision standard spheres of unequal height are fixed to the edges of the machining table. Preferably, the distances l1 and l2 from the center of the machining table to each standard sphere can also be unequal. By controlling the movement of the support, the contact probe collects the relevant coordinates of the standard sphere surface, and fits the axial positions and directions of the A and C axes respectively, thereby completing the A / C axis calibration process. It can be understood that since the A and C axes are independent of each other, the A and C axes can be calibrated separately. That is, during the calibration of one axis, the other axis can be fixed in a specific position. Based on this understanding, the target rotation axis to be calibrated in the following content of this disclosure can be called the rotation axis to be calibrated, and those other than the rotation axis to be calibrated can be called other rotation axes, which will not be elaborated further in the following content.

[0038] Based on this, see Figure 3 This invention illustrates a calibration method for rotary axes in a five-axis machine tool, provided by an embodiment of the present invention. The method may include:

[0039] S301: With other rotation axes fixed except for the rotation axis to be calibrated, the vertex coordinates of at least two standard spheres of different heights at multiple first rotation angle positions are fitted to obtain a first spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated, and the parameters of the first spatial circle model corresponding to each standard sphere are obtained.

[0040] S302: Based on the first spatial circle model, collect the spherical point coordinates of the standard sphere at multiple second rotation angle positions, and fit the collected spherical point coordinates of the standard sphere at multiple second rotation angle positions to obtain a second spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated.

[0041] S303: Obtain the direction of the axis around which the rotation axis to be calibrated revolves based on the second spatial circle model corresponding to each standard sphere, and record the characterization quantity used to characterize the end of the fitting.

[0042] S304: When the feature quantity does not meet the set fitting termination condition, continue to collect the spherical point coordinates of the standard sphere at multiple second rotation angle positions until the feature quantity obtained in the fitting conclusion step meets the set fitting termination condition.

[0043] pass Figure 3The technical solution shown combines the inherent characteristics of a dual-rotary-table five-axis machine tool. It collects position data of at least two standard spheres with varying heights at different rotation axis (A / C axis) angles, then fits the coordinates corresponding to the sphere centers. Finally, by combining the fitted sphere center coordinates with the motion mathematical model of the rotation axis (A / C axis), the position and direction of the rotation axis (A / C axis) are calculated. This enables rapid and stable calibration of the rotation axis (A / C axis), improves the calibration efficiency of the machine tool's rotation axis (A / C axis), and achieves stable calibration of the machine tool's rotation axis (A / C axis).

[0044] for Figure 3 In some implementations of the technical solution shown, when fixing rotation axes other than the axis to be calibrated, the method involves fitting the vertex coordinates of at least two standard spheres of different heights at multiple first rotation angle positions to obtain a first spatial circle model of each standard sphere rotating according to the axis to be calibrated, and obtaining the parameters of the first spatial circle model corresponding to each standard sphere, including:

[0045] With the rotation axes other than the one to be calibrated fixed, the estimated center coordinates of the standard spheres at the multiple first rotation angle positions are obtained based on the vertex coordinates of at least two standard spheres at multiple first rotation angle positions.

[0046] By fitting the estimated center coordinates of the standard spheres, a first spatial circle model of each standard sphere rotating along the axis to be calibrated is obtained, and the parameters of the first spatial circle model corresponding to each standard sphere are acquired.

[0047] Regarding the above implementation method, combined with Figure 2 As shown, in some examples, taking the rotation axis to be calibrated as the C-axis as an example, the A-axis is fixed at a rotation angle of 0° and remains unchanged. The C-axis is rotated to three first rotation angle positions: 0°, 90°, and 180°. Then, the CNC device controls the machining table along the translational axes (X-axis, Y-axis, Z-axis) so that the contact probe contacts and collects the vertex coordinates of the two standard spheres at each first rotation angle position. Combined with the known diameter of the standard spheres, a rough calculation is performed according to the following formula to obtain the estimated values ​​of the center coordinates of the two standard spheres at each first rotation angle position:

[0048]

[0049] Among them, c x c y c z t represents the estimated coordinates of the sphere's center; x , t y , t z Let r be the coordinates of the vertex acquired at a certain first rotation angle position, and r be the radius of the standard sphere.

[0050] In some examples, after obtaining the estimated center coordinates of the two standard spheres at each of the first rotation angle positions, the estimated center coordinates of the two standard spheres at three different first rotation angle positions are used to fit and obtain two first spatial circle models corresponding to the motion trajectories of the two standard spheres rotating along the C-axis, and the parameters of the first spatial circle model corresponding to each standard sphere are obtained according to the first spatial circle model.

[0051] The specific implementation process for the above example includes:

[0052] First, based on the spatial plane equation Ax+By+Cz-D=0 and the estimated coordinates of the center of the standard sphere at three different first rotation angles, the following equations are solved using the least squares method to obtain the model coefficients A, B, C, and D in the spatial plane equation, thereby fitting the plane containing the center of the standard sphere.

[0053]

[0054] Among them, (x i ,y i ,z i ) represents the estimated coordinates of the center of the standard sphere at the i-th first rotation angle position, i = 1, 2, 3.

[0055] Next, based on the definition of the equation of a spatial plane, the normal vector corresponding to the plane containing the center of the standard sphere is obtained.

[0056]

[0057] Subsequently, based on this normal vector, the plane containing the center of the standard sphere is rotated as a whole to a plane parallel to the XOY plane formed by the translational axes X and Y, and the rotation matrix required for the plane rotation is calculated.

[0058] In detail, the axis of rotation for the overall rotation of the plane is shown in the following equation:

[0059]

[0060] The rotation angle of the entire plane is shown in the following formula:

[0061]

[0062] Based on the rotation axis and rotation angle, the rotation matrix is ​​obtained as shown in the following formula:

[0063]

[0064] Where, k x k y k z Representing the rotation axis k respectivelyrot The components of (x,y,z) on the X, Y, and Z axes.

[0065] Using the aforementioned rotation matrix, the coordinates of the sphere's center are transformed to lie parallel to the xoy plane. Then, the equation of the two-dimensional plane circle (xc) is... x ) 2 +(yc y ) 2 =r 2 After expansion, we get x 2 +y 2 +c x 2 +c y 2 -2c x x-2c y y = r 2 ;

[0066] Let A = 2c x B = 2c y C = c x 2 +c y 2 -r 2 Then the equation of the two-dimensional plane circle can be simplified to Ax + By - C = x 2 +y 2 ;

[0067] Next, based on the estimated coordinates of the center of the standard sphere at three different first rotation angles, the system of equations is solved using the least squares method. Thus, the center coordinates and radius of the first spatial circle model are obtained, where the center coordinates are... z i The z-values ​​are the sphere center coordinates after being transformed to the xoy plane from the three different first rotation angle positions mentioned above.

[0068] Finally, the coordinates of the center of the plane circle are passed through the inverse moment R of R(k,θ). -1 The center of the circle in the spatial plane is obtained by transforming the (k,θ) matrix. It should be noted that, since this is a rigid body rotation, R... -1 (k,θ)=R(k,-θ), that is:

[0069]

[0070] Therefore, the first spatial circle model of the standard sphere can be obtained through the above calculations. It should be noted that, for... Figure 2The two standard spheres shown can both obtain the corresponding first spatial circle model through the above calculation process, and the corresponding spatial circle model parameters can be set as f1′(x,y,z,r,i,j,、f2′(x,y,z,r,i,j,k).

[0071] for Figure 3 In some implementations of the technical solution shown, the step of acquiring the spherical point coordinates of the standard sphere at multiple second rotation angle positions based on the first spatial circle model, and fitting the acquired spherical point coordinates of the standard sphere at multiple second rotation angle positions to obtain a second spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated, includes:

[0072] Based on the first spatial circle model, the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions are collected, and the measured values ​​of the center coordinates of the standard sphere at each second rotation angle are obtained by fitting the collected coordinates of the spherical points of the standard sphere at multiple second rotation angle positions.

[0073] Based on the measured coordinates of the center of the standard sphere at each second rotation angle, a second spatial circle model is fitted to each standard sphere rotating along the axis to be calibrated.

[0074] Regarding the above implementation method, it is still combined with the aforementioned Figure 2 As shown, in some examples, taking the C-axis as the axis to be calibrated, the machine tool position p1(x1,y1,z1,a1,c1) and the center position f1′(x,y,z,r,i,j,k) corresponding to the first sphere center are used as references. The travel range of the C-axis is divided into six equally spaced second rotation angles, such as 0°, 60°, 120°, 180°, 240°, and 300°. The positions of the standard sphere centers corresponding to these second rotation angles are calculated. Specifically, for one of the two standard spheres, the i-th rotation angle c... i The machine tool position parameters at that location are set to...

[0075] in, Represented as c i Machine tool movement coordinates at angle c1, where 'a' represents the theoretical vector N of the point at angle c1 relative to the center of the circle. theory The actual vector N formed between the actual point p1(x1,y1,z1) and the center of the circle f1′(x,y,z) actual The angle between them, r is the radius of the first spatial circle model of the fitted standard sphere, f1′(x,y,z) are the coordinates of the center of the first spatial circle model of the standard sphere; R(j,α) represents the theoretical vector of the point at angle c1 on the circumference relative to the center of the circle. Rotate to the actual vector formed between the actual point p1(x1,y1,z1) and the center of the circle f1′(x,y,z). The required transformation vector, Normalize() represents vector normalization, and R(j,α) has the following form:

[0076]

[0077]

[0078] In some examples, based on the sphere center position at the second rotation angle obtained through the above process, spherical coordinates are collected and combined with... Figure 4 Specifically, assuming the center of the sphere is at position f at the i-th second rotation angle position. c (x i ,y i ,z i If the number of layers in a sphere is n, then the point p in the j-th layer of the sphere with a circumferential angle of k (set to 0 in the positive x-axis coordinate system) is denoted as p. j,k (x,y,z); then we have

[0079]

[0080] After completing the spherical data acquisition at all second rotation angle positions, the measured values ​​of the sphere's center coordinates at the corresponding second rotation angle positions can be fitted using the acquired coordinates.

[0081] Specifically, by using the equation of the space sphere (xx) c ) 2 +(yy c ) 2 +(zz c ) 2 =r 2 Expanding, we get 2x c x+2y c y+2z c z-(x c 2 +y c 2 +z c 2 -r 2 )=x 2 +y 2 +z 2 Let A = 2x c B = 2y c C = 2z c D = x c 2 +y c 2+z c 2 -r 2 We can obtain Ax + By + Cz - D = x 2 +y 2 +z 2 ;

[0082] The following system of equations was solved using the collected coordinates and the least squares method:

[0083]

[0084] The coefficients A, B, C, and D obtained by solving can be used to obtain the measured coordinates of the sphere's center at the i-th position of the second rotation angle.

[0085] In some examples, for either of the two standard spheres, after obtaining the measured values ​​of the sphere center coordinates at all the second rotation angle positions, it is possible to fit the first spatial circle model according to the specific implementation process described above, thereby obtaining the second spatial circle models corresponding to the two standard spheres respectively, and the parameters of the corresponding second spatial circle models can be set as f1(x,y,z,r,i,j,k) and f2(x,y,z,r,i,j,k).

[0086] It should be noted that the above examples all use the C-axis as the axis of rotation to be calibrated. However, when the A-axis is set as the axis of rotation to be calibrated, the calibration diagram is as follows: Figure 5 As shown, it can be seen that during the calibration of the A-axis, the process of acquiring spherical coordinates is affected by the interference of the standard spherical support rod. Therefore, after rotating to a certain angle, some areas of the upper hemisphere cannot be acquired (e.g., Figure 6 (The marked uncollectible area). Therefore, when calculating the guiding coordinates for spherical acquisition, this interference area needs to be avoided. The size of this area is related to the angle of rotation along the A-axis, and the calculation process is as follows:

[0087] Establish a coordinate system at the center of the sphere as follows: Figure 7 As shown, the interference region is within the h region on the Z-axis, and its maximum region in the xoy plane is within the 2β angle range. Let the radius of the support rod be r, the radius of the standard sphere be R, and the rotation angle along the A-axis be A, then according to... Figure 7 The triangular relationship in the equation yields the following function:

[0088]

[0089] It is worth noting that, considering the convenience of engineering implementation and to ensure that the probe does not touch the support rod due to interference to the greatest extent, in the implementation of this invention, as long as it enters the h region on Z, a motion restricted area is uniformly established on the xoy plane with the maximum angle range, i.e., 2β.

[0090] When collecting spherical points in layers, if a point falls within the restricted area, its collection must be skipped. Therefore, when planning layered collection points, for layers where the Z-value enters the restricted area, the angle interval should be [missing value]. Where n is the number of sampling points per layer. This process resolves the interference problem caused by the support rod during A-axis calibration.

[0091] for Figure 3 In some implementations of the technical solution shown, the step of obtaining the axial direction of the rotation axis to be calibrated based on the second spatial circle model corresponding to each standard sphere, and recording the characterization quantity used to characterize the end of the fitting, includes:

[0092] The average center coordinates of the second spatial circle model corresponding to all standard spheres are used to determine the reference point on the rotation axis to be calibrated.

[0093] The vector to be processed is formed by connecting the centers of the second-space circles corresponding to all standard spheres;

[0094] The sum of the vector to be processed and the normal vectors of each second spatial circle model is normalized to generate the evaluation vector that represents the direction of the axis around which the rotation axis to be calibrated is located.

[0095] The fitting error is generated based on the distance between the vector to be evaluated and the coordinates of the reference point, which is used to characterize the end of the fitting process.

[0096] Regarding the above implementation method, combined with the aforementioned examples and Figure 8 As shown in (a)(b). Figure 8 (a) is a schematic diagram of determining the direction of the axis with the C-axis as the rotation axis to be calibrated. Figure 8 (b) is a schematic diagram of determining the direction of the axis with axis A as the rotation axis to be calibrated. Figure 8 In (a) and (b), the two circles represent the second-space circular models corresponding to the two standard spheres, respectively. The points on the circles represent the coordinate trajectories of the center of the standard spheres on the second-space circular models. Oa and Ob represent the centers of the fitted second-space circular models, respectively. The arrows nora and norb represent the normal vectors of the second-space circular models corresponding to the standard spheres, respectively. Direction. Theoretically, the second spatial circle models corresponding to the two standard spheres should be concentric circles, with their centers both lying on the axis around which the rotation axis to be calibrated rests. Therefore, the average value p(x,y,z) of the centers of the two second spatial circle models should also lie on the axis around which the rotation axis to be calibrated rests, and this should be set as a reference point on that axis. Then, a vector to be processed is formed between the centers of the two second spatial circle models. The vector to be processed should be the normal vector of the second space circle model corresponding to the two standard spheres. Parallel and parallel to the direction of the axis around which the rotating axis to be calibrated is wound.

[0097] Based on this, the embodiments of the present invention calculate the average value of each component of the three vectors to form the vector to be evaluated. The axis around which the rotation axis to be calibrated is used, and considering that the reference point p(x,y,z) should be on the vector to be evaluated, the fitting error of the above scheme is characterized by calculating whether the reference point p(x,y,z) is on the vector to be evaluated, that is, the distance between the reference point p(x,y,z) and the vector to be evaluated.

[0098] Based on the above implementation, in some examples, the method further includes:

[0099] If the feature quantity meets the set fitting termination condition, then the position and direction of the axis around which the rotation axis to be calibrated is located are confirmed.

[0100] In the above example, specifically, if the fitting error meets the set error threshold, it is determined that the set fitting termination condition is met, and the position and direction of the axis around which the rotation axis to be calibrated is determined according to the reference point and the vector to be evaluated.

[0101] Based on the above implementation, in some examples, when the feature quantity does not meet the set fitting termination condition, the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions are continuously collected until the feature quantity meets the set fitting termination condition, including:

[0102] If the fitting error does not meet the set error threshold, the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions are collected and the second spatial circle model is fitted until the fitting error meets the set error threshold.

[0103] For the above example, specifically in the embodiments of the present invention, the error threshold δ 阈值 It is preferable to present the values ​​in the form of a numerical range, specifically: Usually, you can choose less than If the fitting error does not meet the above error threshold, the next fitting iteration is required. Specifically, in the next fitting process, the second spatial circle model obtained in this fitting is used as the first spatial circle model to select multiple second rotation angles in the next fitting, and the second spatial circle model fitting continues until the fitting error meets the set error threshold.

[0104] In addition, a threshold can be set based on the number of times the second spatial circle model is repeatedly fitted. When the number of executions meets the threshold, the fitting termination condition is confirmed.

[0105] After calibrating the A-axis and C-axis using the above technical solutions, the correspondence between the workpiece coordinate system and the five-axis machine tool coordinate system can be established by combining positioning methods such as six-point workpiece positioning. Finally, the coordinates on the workpiece are converted into the corresponding machine tool coordinates, providing accurate machine tool motion data for subsequent workpiece processing or inspection.

[0106] Based on the same inventive concept as the aforementioned technical solution, see [link to inventive concept]. Figure 9 This illustration shows a calibration device 90 for the rotary axis of a five-axis machine tool according to an embodiment of the present invention. The device 90 includes: a first fitting section 901, a data acquisition section 902, a second fitting section 903, an acquisition section 904, and a determination section 905; wherein,

[0107] The first fitting part 901 is configured to, under the condition of fixing other rotation axes except the rotation axis to be calibrated, fit the vertex coordinate values ​​of at least two standard spheres of different heights at multiple first rotation angle positions to obtain a first spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated, and obtain the first spatial circle model parameters corresponding to each standard sphere.

[0108] The acquisition unit 902 is configured to acquire the coordinates of spherical points of a standard sphere at multiple second rotation angle positions based on the first spatial circle model.

[0109] The second fitting part 903 is configured to fit the spherical point coordinates of the collected standard spheres at multiple second rotation angle positions to obtain a second spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated.

[0110] The acquisition part 904 is configured to obtain the direction of the axis around which the rotation axis to be calibrated revolves based on the second spatial circle model corresponding to each standard sphere, and record the characterization quantity used to characterize the end of the fitting.

[0111] The determination section 905 is configured to continue collecting the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions when the feature quantity does not meet the set fitting termination condition, until the feature quantity obtained in the fitting conclusion step meets the set fitting termination condition.

[0112] In some examples of the above scheme, the determination part 905 is further configured as follows:

[0113] If the feature quantity meets the set fitting termination condition, then the position and direction of the axis around which the rotation axis to be calibrated is located are confirmed.

[0114] For the above scheme, in some examples, the first fitting portion 901 is configured as follows:

[0115] With the rotation axes other than the one to be calibrated fixed, the estimated center coordinates of the standard spheres at the multiple first rotation angle positions are obtained based on the vertex coordinates of at least two standard spheres at multiple first rotation angle positions.

[0116] By fitting the estimated center coordinates of the standard spheres, a first spatial circle model of each standard sphere rotating along the axis to be calibrated is obtained, and the parameters of the first spatial circle model corresponding to each standard sphere are acquired.

[0117] In some examples of the above scheme, the acquisition part 902 is configured to acquire the spherical point coordinates of the standard sphere at multiple second rotation angle positions based on the first spatial circle model, and to obtain the measured values ​​of the center coordinates of the standard sphere at each second rotation angle by fitting the acquired spherical point coordinates of the standard sphere at multiple second rotation angle positions.

[0118] The second fitting part 903 is configured to fit a second spatial circle model of each standard ball rotating along the axis to be calibrated, based on the measured values ​​of the ball center coordinates of the standard ball at each second rotation angle.

[0119] In some examples of the above scheme, the acquisition part 902 is further configured to: corresponding to the rotation axis to be calibrated as the A-axis, based on the influence of standard sphere interference, set the spherical point coordinates of the acquisition standard sphere at multiple second rotation angle positions to avoid the interference area of ​​acquisition.

[0120] In some examples of the above scheme, the acquisition part 904 is configured as follows:

[0121] The average center coordinates of the second spatial circle model corresponding to all standard spheres are used to determine the reference point on the rotation axis to be calibrated.

[0122] The vector to be processed is formed by connecting the centers of the second-space circles corresponding to all standard spheres;

[0123] The sum of the vector to be processed and the normal vectors of each second spatial circle model is normalized to generate the evaluation vector that represents the direction of the axis around which the rotation axis to be calibrated is located.

[0124] The fitting error is generated based on the distance between the vector to be evaluated and the coordinates of the reference point, which is used to characterize the end of the fitting process.

[0125] In the above scheme, the determination part 905 is configured as follows:

[0126] If the fitting error meets the set error threshold, then the set fitting termination condition is determined, and the position and direction of the axis around which the rotation axis to be calibrated is located are confirmed based on the reference point and the vector to be evaluated.

[0127] In the above scheme, the determination part 905 is configured as follows:

[0128] If the fitting error does not meet the set error threshold, the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions will continue to be collected and the second spatial circle model will be fitted until the feature quantity meets the set fitting termination condition.

[0129] Understandably, in this embodiment, "part" can be a part of a circuit, a part of a processor, a part of a program or software, etc., or it can be a unit, a module, or a non-modular one.

[0130] Furthermore, in this embodiment, the components can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional module.

[0131] If the integrated unit is implemented as a software functional module and not sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this embodiment, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the method described in this embodiment. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0132] Therefore, this embodiment provides a computer storage medium storing a calibration program for the rotary axes of a five-axis machine tool. When the calibration program for the rotary axes of a five-axis machine tool is executed by at least one processor, it implements the steps of the calibration method for the rotary axes of a five-axis machine tool described in the above technical solution.

[0133] Based on the aforementioned calibration device 90 for the rotary axes of a five-axis machine tool and the computer storage medium, see [link to documentation]. Figure 10This illustration shows a specific hardware structure of a computing device 100 provided by an embodiment of the present invention, capable of implementing the aforementioned calibration device 90 for the rotary axes of a five-axis machine tool. The computing device 100 can be a wireless device, a mobile or cellular phone (including so-called smartphones), a personal digital assistant (PDA), a video game console (including a video display, a mobile video game device, a mobile video conferencing unit), a laptop computer, a desktop computer, a set-top box, a tablet computing device, an e-book reader, a fixed or mobile media player, etc. The computing device 100 includes: a communication interface 1001, a memory 1002, and a processor 1003; the various components are coupled together through a bus system 1004. It is understood that the bus system 1004 is used to realize the connection and communication between these components. In addition to a data bus, the bus system 1004 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in... Figure 10 The general designated all buses as Bus System 1004.

[0134] The communication interface 1001 is used for receiving and sending signals during the process of sending and receiving information with other external network elements;

[0135] The memory 1002 is used to store computer programs that can run on the processor 1003;

[0136] The processor 1003 is used to execute the steps of the calibration method for the rotary axis of a five-axis machine tool described in the above technical solution when running the computer program.

[0137] It is understood that the memory 1002 in the embodiments of the present invention can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate Synchronous DRAM (DDRSDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchlink DRAM (SLDRAM), and Direct Rambus RAM (DRRAM). The memory 1002 of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0138] The processor 1003 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of the processor 1003 or by instructions in software form. The processor 1003 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this invention can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory 1002. Processor 1003 reads the information in memory 1002 and completes the steps of the above method in conjunction with its hardware.

[0139] It is understood that the embodiments described herein can be implemented in hardware, software, firmware, middleware, microcode, or a combination thereof. For hardware implementation, the processing unit can be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers, microprocessors, other electronic units for performing the functions described herein, or combinations thereof.

[0140] For software implementation, the techniques described herein can be achieved through modules (e.g., procedures, functions, etc.) that perform the functions described herein. The software code can be stored in memory and executed by a processor. The memory can be implemented within the processor or externally.

[0141] It is understood that the exemplary technical solutions described above for the calibration device 90 and computing device 100 for the rotary axes of a five-axis machine tool belong to the same concept as the aforementioned technical solutions for the calibration method for the rotary axes of a five-axis machine tool. Therefore, all details not described in detail above for the calibration device 90 and computing device 100 for the rotary axes of a five-axis machine tool can be found in the description of the aforementioned technical solutions for the calibration method for the rotary axes of a five-axis machine tool. This embodiment of the invention will not elaborate further on these details.

[0142] It should be noted that the technical solutions described in the embodiments of the present invention can be combined arbitrarily without conflict.

[0143] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A calibration method for rotary axes in a five-axis machine tool, characterized in that, The method includes: With other rotation axes fixed except for the rotation axis to be calibrated, the vertex coordinates of at least two standard spheres of different heights at multiple first rotation angle positions are fitted to obtain a first spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated, and the parameters of the first spatial circle model corresponding to each standard sphere are obtained. Based on the first spatial circle model, the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions are collected, and the second spatial circle model of each standard sphere rotating according to the collected coordinates of the spherical points of the standard sphere at multiple second rotation angle positions is obtained by fitting. The direction of the axis around which the rotation axis to be calibrated is located is obtained based on the second spatial circle model corresponding to each standard sphere, and the characterization quantity used to characterize the end of the fitting is recorded. If the characterization quantity does not meet the set fitting termination condition, continue to collect the spherical point coordinates of the standard sphere at multiple second rotation angle positions until the characterization quantity obtained in the fitting conclusion step meets the set fitting termination condition. The process involves obtaining the axial direction of the rotation axis to be calibrated based on the second spatial circle model corresponding to each standard sphere, and recording the representational quantities used to characterize the end of the fitting, including: The average center coordinates of the second spatial circle model corresponding to all standard spheres are used to determine the reference point on the rotation axis to be calibrated. The vector to be processed is formed by connecting the centers of the second-space circles corresponding to all standard spheres; The sum of the vector to be processed and the normal vectors of each second spatial circle model is normalized to generate the evaluation vector that represents the direction of the axis around which the rotation axis to be calibrated is located. The fitting error is generated based on the distance between the vector to be evaluated and the coordinates of the reference point, which is used to characterize the end of the fitting process.

2. The method according to claim 1, characterized in that, The method further includes: If the characterization quantity meets the set fitting termination condition, then the position and direction of the axis around which the rotation axis to be calibrated is located are confirmed.

3. The method according to claim 1 or 2, characterized in that, With all rotation axes except the one to be calibrated fixed, the vertex coordinates of at least two standard spheres of different heights at multiple first rotation angle positions are fitted to obtain a first spatial circle model of each standard sphere rotating according to the axis to be calibrated, and the parameters of the first spatial circle model corresponding to each standard sphere are obtained, including: With the rotation axes other than the one to be calibrated fixed, the estimated center coordinates of the standard spheres at the multiple first rotation angle positions are obtained based on the vertex coordinates of at least two standard spheres at multiple first rotation angle positions. By fitting the estimated center coordinates of the standard spheres, a first spatial circle model of each standard sphere rotating along the axis to be calibrated is obtained, and the parameters of the first spatial circle model corresponding to each standard sphere are acquired.

4. The method according to claim 1 or 2, characterized in that, The step of acquiring the spherical point coordinates of a standard sphere at multiple second rotation angle positions based on the first spatial circle model, and fitting the acquired spherical point coordinates of the standard sphere at multiple second rotation angle positions to obtain a second spatial circle model of each standard sphere rotating according to the axis to be calibrated, includes: Based on the first spatial circle model, the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions are collected, and the measured values ​​of the center coordinates of the standard sphere at each second rotation angle are obtained by fitting the collected coordinates of the spherical points of the standard sphere at multiple second rotation angle positions. Based on the measured coordinates of the center of the standard sphere at each second rotation angle, a second spatial circle model is fitted to each standard sphere rotating along the axis to be calibrated.

5. The method according to claim 4, characterized in that, Corresponding to the rotation axis to be calibrated being the A-axis, the method further includes: Based on the influence of standard sphere interference, the coordinates of spherical points at multiple second rotation angle positions of the acquired standard sphere are set to avoid the interference zone during acquisition.

6. The method according to claim 2, characterized in that, If the characterization quantity meets the set fitting termination condition, then confirming the position and direction of the axis around which the rotation axis to be calibrated revolves includes: If the fitting error meets the set error threshold, then the set fitting termination condition is determined, and the position and direction of the axis around which the rotation axis to be calibrated is located are confirmed based on the reference point and the vector to be evaluated.

7. The method according to claim 1 or 2, characterized in that, When the characterization quantity does not meet the set fitting termination condition, the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions are continuously collected until the characterization quantity meets the set fitting termination condition, including: If the fitting error does not meet the set error threshold, the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions are collected and the second spatial circle model is fitted until the fitting error meets the set error threshold.

8. A calibration device for rotary axes in a five-axis machine tool, characterized in that, The calibration device for rotary axes in a five-axis machine tool is used to perform the steps of the calibration method for rotary axes in a five-axis machine tool as described in any one of claims 1 to 7, comprising: a first fitting part, a data acquisition part, a second fitting part, an acquisition part, and a determination part; wherein, The first fitting part is configured to, under the condition of fixing other rotation axes except the rotation axis to be calibrated, fit the vertex coordinate values ​​of at least two standard spheres of different heights at multiple first rotation angle positions to obtain a first spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated, and obtain the first spatial circle model parameters corresponding to each standard sphere. The acquisition section is configured to acquire the coordinates of spherical points of a standard sphere at multiple second rotation angle positions based on the first spatial circle model. The second fitting part is configured to fit the spherical point coordinates of the collected standard spheres at multiple second rotation angle positions to obtain a second spatial circle model of each standard sphere rotating according to the rotation axis to be calibrated. The acquisition part is configured to obtain the direction of the axis around which the rotation axis to be calibrated revolves based on the second spatial circle model corresponding to each standard sphere, and record the characterization quantity used to characterize the end of the fitting. The determination section is configured to continue collecting the coordinates of the spherical points of the standard sphere at multiple second rotation angle positions when the characterization quantity does not meet the set fitting termination condition, until the characterization quantity obtained in the fitting conclusion step meets the set fitting termination condition. The acquisition part is further configured to determine the reference point on the rotation axis to be calibrated based on the average value of the center coordinates of the second spatial circle models corresponding to all standard spheres; form a vector to be processed based on the line connecting the centers of the second spatial circle models corresponding to all standard spheres; perform vector normalization processing on the sum of the vector to be processed and the normal vectors of each second spatial circle model to generate a vector to be evaluated representing the direction of the axis around which the rotation axis to be calibrated is located; and generate a fitting error for representing the end of fitting based on the distance between the vector to be evaluated and the coordinates of the reference point.

9. A computer storage medium, characterized in that, The computer storage medium stores a calibration program for the rotary axes of a five-axis machine tool, which, when executed by at least one processor, implements the steps of the calibration method for the rotary axes of a five-axis machine tool as described in any one of claims 1 to 7.

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