Workpiece alignment method and device for secondary clamping of machine tool and computer storage medium

Abstract

The application provides a workpiece alignment method and device for secondary clamping of a machine tool and a computer storage medium. The project development method comprises the following steps: installing a trigger type measuring needle on a machine tool spindle and installing a measuring module on a workpiece; controlling the measuring needle to move to a plurality of measuring points on the measuring module before and after secondary clamping, respectively, and recording a plurality of collision point coordinates of the measuring needle and the measuring module; calculating the center coordinates of the measuring module before and after secondary clamping by using the plurality of collision point coordinates before and after secondary clamping, respectively; calculating an alignment matrix by using the center coordinates of the measuring module before and after secondary clamping; and modifying an initial machining code based on the alignment matrix, so that the machine tool implements accurate machining on the workpiece according to the machining code after alignment. Through the above method, the project development method of the application can effectively solve the workpiece position and attitude alignment problem, improve the alignment speed of the secondary clamping of the workpiece, reduce the measurement time, and thus greatly reduce the labor intensity of the operator.

Description

Technical Field

[0001] This application relates to the field of CNC machine tool technology, and in particular to a workpiece alignment method, device, and computer storage medium for secondary clamping of a machine tool. Background Technology

[0002] In CNC machine tool processing, problems such as product position shifting leading to dimensional inaccuracies not meeting set requirements often occur. This issue is frequently caused by low workpiece alignment accuracy during secondary clamping. Therefore, secondary clamping workpiece alignment plays a crucial role in CNC systems, and the speed and accuracy of workpiece alignment directly and significantly impact production efficiency and processing quality.

[0003] Traditional manual measurement methods such as the pad block method and the lever percentage method have low accuracy and lack versatility. In addition, the current method of resetting the workpiece coordinates based on the coordinate system of the reference hole can only be used for the alignment of coordinates in two-dimensional space. Moreover, it is more sensitive to errors and lacks stability when measuring the reference hole position. Summary of the Invention

[0004] This application provides a workpiece alignment method, apparatus, and computer storage medium for secondary clamping of a machine tool.

[0005] This application provides a workpiece alignment method for secondary clamping of a machine tool, the workpiece alignment method comprising:

[0006] A trigger-type probe is installed on the machine tool spindle, and a measurement module is installed on the workpiece;

[0007] The probe is controlled to move to multiple measurement points on the measurement module before and after the second clamping, and the coordinates of multiple collision points between the probe and the measurement module are recorded.

[0008] The center coordinates of the measurement module before and after the secondary clamping are calculated using the coordinates of the multiple collision points before and after the secondary clamping.

[0009] The alignment matrix is ​​calculated using the center coordinates of the measurement module before and after the secondary clamping.

[0010] The initial machining code is modified based on the alignment matrix so that the machine tool can perform precise machining on the workpiece according to the aligned machining code.

[0011] Wherein, after installing the trigger-type probe on the machine tool spindle, it includes:

[0012] The probe is calibrated using a lever dial indicator so that the ball at the end of the probe coincides with the spindle axis of the machine tool.

[0013] The step of installing the measuring module on the workpiece includes:

[0014] Three non-collinear standard spheres are installed on the workpiece.

[0015] The workpiece coordinate system includes the X-axis, Y-axis, and Z-axis.

[0016] The method involves controlling the probe to move to multiple measurement points on the measurement module before and after the secondary clamping, and recording the coordinates of multiple collision points between the probe and the measurement module, including:

[0017] The probe is controlled to move along the positive X-axis, the negative X-axis, the positive Y-axis, and the negative Y-axis respectively, and to collide with the standard ball before and after the second clamping.

[0018] The coordinates of the multiple collision points in the workpiece coordinate system are locked.

[0019] The step of calculating the center coordinates of the measurement module before and after the secondary clamping using the coordinates of the multiple collision points before and after the secondary clamping includes:

[0020] Obtain the coordinates of the four collision points corresponding to each of the three measurement points before the second clamping;

[0021] A set of coordinate equations for the center of the sphere before secondary clamping is established by using the relationship that the four collision points corresponding to each measurement point are equidistant from the center of the standard sphere.

[0022] Input the coordinates of the four collision points corresponding to each of the three measurement points before the second clamping into the system of equations for the center of the sphere before the second clamping, and calculate the center coordinates of the standard sphere before the second clamping.

[0023] Obtain the coordinates of the four collision points corresponding to each of the three measurement points after the second clamping;

[0024] A set of coordinate equations for the center of the sphere after secondary clamping is established by using the relationship that the four collision points corresponding to each measurement point are equidistant from the center of the standard sphere.

[0025] Input the coordinates of the four collision points corresponding to each of the three measurement points after the second clamping into the system of equations for the center coordinates of the sphere after the second clamping, and calculate the center coordinates of the standard sphere after the second clamping.

[0026] The step of calculating the alignment matrix using the center coordinates of the measurement module before and after the secondary clamping includes:

[0027] Obtain the local coordinate system before the second clamping and the local coordinate system after the second clamping;

[0028] Calculate the first homogeneous transformation matrix between the local coordinate system and the workpiece coordinate system before the second clamping, and calculate the second homogeneous transformation matrix between the local coordinate system and the workpiece coordinate system after the second clamping;

[0029] Obtain the coordinates of the first fixed point in the local coordinate system of the fixed point marked on the standard ball before the second clamping, and the coordinates of the second fixed point in the local coordinate system of the fixed point after the second clamping;

[0030] The coordinates of the fixed point in the workpiece coordinate system are calculated using the coordinates of the first fixed point and the coordinates of the second fixed point, respectively.

[0031] The alignment matrix is ​​calculated based on the coordinates of the fixed point in the workpiece coordinate system, the first homogeneous transformation matrix, and the second homogeneous transformation matrix.

[0032] The step of obtaining the local coordinate system before the secondary clamping and the local coordinate system after the secondary clamping includes:

[0033] Using the center of the standard sphere before and after the second clamping as the origin of the coordinate system, the unit direction from the center of the sphere to a measurement point as the x-axis, the cross product of the unit direction from the center of the sphere to a measurement point and the unit direction from the center of the sphere to another measurement point as the y-axis, and the z-axis obtained by cross product of the x-axis and y-axis, a local coordinate system before and after the second clamping is established.

[0034] The workpiece alignment method further includes:

[0035] A first plane is established using the center coordinates of the measurement module before the secondary clamping, and the first unit normal vector of the first plane is obtained.

[0036] A second plane is established using the center coordinates of the measurement module after the second clamping, and the second unit normal vector of the second plane is obtained.

[0037] The compensation angle of the rotation axis attitude is calculated using the first unit normal vector and the second unit normal vector.

[0038] The modification of the initial processing code based on the alignment matrix includes:

[0039] The initial machining code is modified based on the alignment matrix and the compensation angle of the rotation axis posture.

[0040] This application also provides a workpiece alignment device for secondary clamping of a machine tool, the workpiece alignment device for secondary clamping of a machine tool includes a memory and a processor, wherein the memory is coupled to the processor;

[0041] The memory is used to store program data, and the processor is used to execute the program data to implement the workpiece alignment method for secondary clamping of the machine tool as described above.

[0042] This application also provides a computer storage medium for storing program data, which, when executed by a processor, is used to implement the workpiece alignment method for secondary clamping of a machine tool as described above.

[0043] The beneficial effects of this application are as follows: The workpiece alignment device for secondary clamping of a machine tool installs a trigger-type probe on the machine tool spindle and a measuring module on the workpiece; it controls the probe to move to multiple measuring points on the measuring module before and after secondary clamping, and records the coordinates of multiple collision points between the probe and the measuring module; it calculates the center coordinates of the measuring module before and after secondary clamping using the coordinates of the multiple collision points; it calculates the alignment matrix using the center coordinates of the measuring module before and after secondary clamping; and it modifies the initial machining code based on the alignment matrix so that the machine tool can accurately machine the workpiece according to the aligned machining code. Through the above methods, the project development method of this application can effectively solve the problem of workpiece position and orientation alignment, improve the alignment speed of secondary clamping of workpieces, reduce measurement time, and thus significantly reduce the labor intensity of operators. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0045] Figure 1 This is a flowchart illustrating an embodiment of the workpiece alignment method for secondary clamping of a machine tool provided in this application;

[0046] Figure 2 This is a schematic diagram of the structure of the workpiece mounting standard ball provided in this application;

[0047] Figure 3 This is a schematic diagram of the structure of the probe measuring the standard ball provided in this application;

[0048] Figure 4 yes Figure 1 The schematic diagram of step S103 of the workpiece alignment method is shown.

[0049] Figure 5 yes Figure 1 The schematic diagram of step S104 of the workpiece alignment method is shown.

[0050] Figure 6This is a schematic diagram of the sphere center coordinate system before and after the secondary clamping provided in this application;

[0051] Figure 7 This is a schematic diagram of an embodiment of the workpiece alignment device for secondary clamping of a machine tool provided in this application;

[0052] Figure 8 This is a schematic diagram of another embodiment of the workpiece alignment device for secondary clamping of machine tools provided in this application;

[0053] Figure 9 This is a schematic diagram of the structure of an embodiment of the computer storage medium provided in this application. Detailed Implementation

[0054] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0055] The workpiece alignment method for secondary clamping of a machine tool according to the embodiments of this application can be applied to a five-axis linkage machine tool. A five-axis linkage machine tool adds two rotary axes to a traditional three-axis machine tool (three linear axes), thereby gaining the ability to process complex curved surfaces. It is widely used for processing high-precision workpieces such as aircraft parts and turbine propellers. Furthermore, the workpiece alignment in this embodiment specifically refers to automatically finding the position and orientation of the workpiece using measuring instruments and rotating and moving the workpiece to the accurate position (ideal orientation) that the workpiece should be in during processing, as pre-defined in the process design stage. The workpiece alignment method for secondary clamping of a machine tool according to the embodiments of this application can effectively improve the workpiece machining yield and production efficiency.

[0056] Based on the above fundamental principles of workpiece alignment, this application further provides a workpiece alignment method for secondary clamping of a machine tool. For details, please refer to [link to relevant documentation]. Figure 1 , Figure 1 This is a flowchart illustrating an embodiment of the workpiece alignment method for secondary clamping of a machine tool provided in this application.

[0057] The workpiece alignment method for secondary clamping of machine tools disclosed in this application is applied to a workpiece alignment device equipped with a computing system. The workpiece alignment device can be a server, a terminal device, or a system in which the server and terminal device cooperate. Correspondingly, all components of the electronic device, such as units, subunits, modules, and submodules, can be entirely housed in the server, entirely in the terminal device, or separately in both the server and the terminal device.

[0058] Furthermore, the aforementioned server can be either hardware or software. When the server is hardware, it can be implemented as a distributed server cluster consisting of multiple servers, or as a single server. When the server is software, it can be implemented as multiple software programs or software modules, such as software or software modules used to provide distributed servers, or as a single software program or software module; no specific limitation is made here. In some possible implementations, the workpiece alignment method of this application embodiment can be implemented by a processor calling computer-readable instructions stored in memory. Specifically, the workpiece alignment device of this application embodiment can also be a machine tool itself with computing capabilities, such as a specific model of an AC dual-rotary table five-axis linkage machine tool.

[0059] like Figure 1 As shown, the workpiece alignment method for secondary clamping of a machine tool according to an embodiment of this application specifically includes the following steps:

[0060] Step S101: Install a trigger-type probe on the machine tool spindle and a measurement module on the workpiece.

[0061] In this process, the operator installs a trigger-type probe on the machine tool spindle and a measuring module on the workpiece. The measuring module is fixed to the workpiece, meaning that the relative distance between the measuring module and the workpiece should remain constant during clamping. The measuring module can be any measuring component whose center coordinates are easily calculated; for example, a standard sphere is used in this embodiment. Specifically, the test objects in this embodiment are three non-collinear standard spheres that remain stationary on the workpiece before and after the second clamping, such as... Figure 2 As shown, three non-collinear standard spheres B can be mounted on workpiece A. In the following description of the workpiece calibration method, the standard spheres are used as the measurement module. Other reasonable measurement structures can also be used as the measurement module of this application, and will not be described in detail here.

[0062] In addition, the workpiece alignment device can also use a lever to calibrate the position of the probe, so that the ball at the end of the probe coincides with the axis of the machine tool spindle as much as possible, ensuring the accuracy of the workpiece alignment method.

[0063] Step S102: Control the probe to move to multiple measurement points on the measurement module before and after the secondary clamping, and record the coordinates of multiple collision points between the probe and the measurement module.

[0064] The workpiece alignment device, through programming, allows the CNC system to drive the probe to the measuring point on the standard ball. Specifically, as follows... Figure 3 As shown, the workpiece alignment device drives the probe to collide with the standard ball before and after the second clamping along the positive X-axis, negative X-axis, positive Y-axis, and negative Y-axis directions of the workpiece coordinate system, respectively, and locks the X, Y, and Z coordinate values ​​of the collision points in the workpiece coordinate system, i.e., X...i Y i Z i , i = 1, 2, 3, 4.

[0065] In this way, the workpiece alignment device can obtain the coordinates of the four collision points corresponding to each measurement point before the second clamping, and the coordinates of the four collision points corresponding to each measurement point after the second clamping.

[0066] In this embodiment of the application, the workpiece coordinate system is a coordinate system set with a fixed point of the workpiece as the origin. The fixed point can be the vertex, center point, or any other specified fixed point of the workpiece.

[0067] Step S103: Calculate the center coordinates of the measurement module before and after the secondary clamping using the coordinates of multiple collision points before and after the secondary clamping.

[0068] The workpiece alignment device uses the coordinates of multiple collision points before and after the second clamping to calculate the center coordinates of the measurement module before and after the second clamping, and the center coordinates of the standard ball are the ball center coordinates.

[0069] Specifically, for a standard sphere, the point of collision is considered a point on the sphere's surface, and the distance between any point of collision and the center of the standard sphere is fixed, equal to the radius of the standard sphere. Therefore, the workpiece alignment device can calculate the coordinates of the center of the standard sphere based on the above principle and the coordinates of multiple collision points.

[0070] Please refer to details. Figure 4 , Figure 4 yes Figure 1 The diagram shows the detailed process flow of step S103 in the workpiece alignment method. Figure 4 As shown, step S103 specifically includes the following sub-steps:

[0071] Step S301: Obtain the coordinates of the four collision points corresponding to each of the three measurement points before the second clamping.

[0072] The workpiece alignment device determines the coordinates of the four collision points before the second clamping, which are (X1, Y1), (X2, Y2), (X3, Y3), and (X4, Y4).

[0073] Step S302: Establish a set of coordinate equations for the center of the sphere before secondary clamping by utilizing the relationship that the four collision points corresponding to each measurement point are equidistant from the center of the standard sphere.

[0074] The workpiece alignment device utilizes the relationship that the distance between the collision point and the center of the standard sphere is equal to establish a set of coordinate equations for the sphere's center before secondary clamping, namely:

[0075] (X1-X Sj ) 2 +(Y1-YSj ) 2 +(Z1-Z Sj ) 2 =(X2-X) Sj ) 2 +(Y2-Y Sj ) 2 +(Z2-Z Sj ) 2

[0076] (X1-X Sj ) 2 +(Y1-Y Sj ) 2 +(Z1-Z Sj ) 2 =(X3-X) Sj ) 2 +(Y3-Y Sj ) 2 +(Z3-Z Sj ) 2

[0077] (X1-X Sj ) 2 +(Y1-Y Sj ) 2 +(Z1-Z Sj ) 2 =(X4-X) Sj ) 2 +(Y4-Y Sj ) 2 +(Z4-Z Sj ) 2

[0078] Among them, (X) Sj Y Sj Z Sj ), j = 1, 2, 3 are the coordinates of the center of the standard sphere.

[0079] Step S303: Input the coordinates of the four collision points corresponding to each of the three measurement points before the second clamping into the sphere center coordinate equation system before the second clamping, and calculate the standard sphere center coordinates before the second clamping.

[0080] The workpiece alignment device inputs the coordinates of the four collision points before the second clamping into the above coordinate equation set, and the coordinates of the center of the standard sphere before the second clamping can be obtained by calculating the coordinate equation set.

[0081] For example, in this embodiment of the application, the coordinates of the center of the standard sphere corresponding to the measurement point before the second clamping can be calculated as follows:

[0082] Number x y z a 20.5220 10.2280 51.0375 b 43.3065 10.7972 50.9954 c 31.8116 28.5179 51.0018

[0083] Step S304: Obtain the coordinates of the four collision points corresponding to each of the three measurement points after the second clamping.

[0084] Step S305: Establish a set of coordinate equations for the center of the sphere after secondary clamping by using the relationship that the four collision points corresponding to each measurement point are equidistant from the center of the standard sphere.

[0085] Step S306: Input the coordinates of the four collision points corresponding to each of the three measurement points after the second clamping into the sphere center coordinate equation system after the second clamping, and calculate the sphere center coordinates of the standard sphere after the second clamping.

[0086] Using the same calculation method, the workpiece alignment device can obtain the coordinates of the center of the standard sphere corresponding to the measurement point after secondary clamping:

[0087] Number x y z A 24.0281 -19.6187 58.4160 B 45.0009 -14.5543 65.7611 C 27.7869 -7.6590 75.8749

[0088] The technical content of steps S304 to S306 is basically the same as that of steps S301 to S303, and will not be repeated here.

[0089] Step S104: Calculate the alignment matrix using the center coordinates of the measurement module and the coordinates of the fixed point before and after the second clamping.

[0090] Before calculating the alignment matrix, the workpiece alignment device can mark a fixed point P on the surface of a standard sphere or the workpiece surface. This fixed point remains unchanged in the workpiece coordinate system and can be used as a reference factor for calculating the alignment matrix.

[0091] Please refer to details. Figure 5 , Figure 5 yes Figure 1 The diagram shows the detailed process flow of step S104 in the workpiece alignment method. Figure 5 As shown, step S104 specifically includes the following sub-steps:

[0092] Step S401: Obtain the local coordinate system before the second clamping and the local coordinate system after the second clamping.

[0093] In order to facilitate the description of coordinate transformation, this application introduces two local coordinate systems {M-xyz} and {N-XYZ}, which represent the sphere center coordinate system before the second clamping and the sphere center coordinate system after the second clamping, respectively.

[0094] Specifically, such as Figure 6 As shown, the origin of the coordinate system {M-xyz} is the center *a* of any one of the three standard spheres. The calculation method for center *a* is as described above and will not be repeated here. Centers *b* and *c* are the centers of the other two standard spheres, respectively. Let... The unit direction is taken as the x-axis of the coordinate system {M-xyz}, with The unit direction is taken as the y-axis of the coordinate system {M-xyz}. Simultaneously, using the right-hand rule, the z-axis of the coordinate system {M-xyz} can be calculated as z = x × y. Similarly, the process of establishing the coordinate system {N-XYZ} will not be elaborated here.

[0095] Step S402: Calculate the first homogeneous transformation matrix between the local coordinate system and the workpiece coordinate system before the second clamping, and calculate the second homogeneous transformation matrix between the local coordinate system and the workpiece coordinate system after the second clamping.

[0096] Here, we assume that the workpiece coordinate system of the five-axis machine tool is {Rcs-xyz}.

[0097] The workpiece alignment device calculates the homogeneous transformation matrix between the workpiece coordinate system {Rcs-xdz} and the local coordinate system {M-xyz}. The specific calculation formula is as follows:

[0098]

[0099] Where x, y, and z are the unit vectors of each axis of the local coordinate system {M-xyz}, and a is the origin of the local coordinate system {M-xyz} before the second clamping.

[0100] Similarly, the workpiece alignment device calculates the homogeneous transformation matrix between the workpiece coordinate system {Rcs-xdz} and the local coordinate system {N-XYZ}. The specific calculation formula is as follows:

[0101]

[0102] Where X, Y, and Z are the unit vectors of each axis of the local coordinate system {N-XYZ}, and A is the origin of the local coordinate system {N-XYZ} after the second clamping.

[0103] Step S403: Obtain the coordinates of the first fixed point in the local coordinate system before the second clamping of the fixed point marked on the standard sphere, and the coordinates of the second fixed point in the local coordinate system after the second clamping.

[0104] Here, it is assumed that there is a fixed point P before the second clamping, and the coordinates of the fixed point P in the local coordinate system {M-xyz} are P. M The coordinates of a fixed point P in the local coordinate system {N-XYZ} are P N The coordinates of the fixed point P in the workpiece coordinate system {Rcs-xdz} before and after the second clamping of the workpiece alignment device are calculated as follows:

[0105]

[0106]

[0107] Step S404: Calculate the coordinates of the fixed point in the workpiece coordinate system using the coordinates of the first fixed point and the coordinates of the second fixed point.

[0108] The workpiece alignment device establishes the following equation based on the coordinate values ​​of the fixed point P before and after the secondary clamping:

[0109]

[0110] The following describes the method for finding the inversion of a homogeneous matrix. For example, suppose the homogeneous matrix is:

[0111]

[0112] Then, the inverse of the homogeneous matrix is:

[0113]

[0114] Step S405: Calculate the alignment matrix based on the coordinates of the fixed point in the workpiece coordinate system and the first homogeneous transformation matrix and the second homogeneous transformation matrix.

[0115] The formula for calculating the alignment matrix using the workpiece alignment device is as follows:

[0116]

[0117] Step S105: Modify the initial machining code based on the alignment matrix so that the machine tool can perform precise machining on the workpiece according to the aligned machining code.

[0118] In this embodiment, the alignment parameters to be calculated can be the alignment matrix as shown above, or they can include the alignment matrix as shown above and the compensation angle of the rotation axis posture. The workpiece alignment device calculates the compensation angle of the rotation axis posture as follows:

[0119] The workpiece alignment device constructs plane ABC using the centers of standard spheres a, b, and c before the secondary clamping, and plane ABC using the centers of standard spheres A, B, and C after the secondary clamping. For details, please refer to [reference needed]. Figure 6 The unit normal vector of plane abc is... The unit normal vector of plane ABC is

[0120] The workpiece alignment device is then calculated according to Paden-Kahan subproblem 2. and Two sets of solutions for rotation axis attitude compensation are obtained. Finally, the compensation angles of feasible rotation axis attitudes are retained based on the rotation axis travel limit and the minimum path principle.

[0121] Finally, the workpiece alignment device modifies the coordinate information of the initial NC machining code according to the calculated alignment matrix and rotation axis compensation angle, obtaining the actual machining NC code under secondary clamping. The NC code is a code that the digital signal controlled mechanical controller can recognize and execute. The workpiece alignment device can then perform precise machining of the workpiece based on the aligned NC machining code.

[0122] It should be noted that the workpiece alignment method of this application embodiment is applicable to three-axis machine tools, four-axis machine tools, five-axis machine tools, etc., and is simple to operate and highly versatile.

[0123] The workpiece alignment device for secondary clamping of a machine tool consists of a trigger-type probe mounted on the machine tool spindle and a measuring module mounted on the workpiece. The probe is controlled to move to multiple measuring points on the measuring module before and after secondary clamping, and the coordinates of multiple collision points between the probe and the measuring module are recorded. The center coordinates of the measuring module before and after secondary clamping are calculated using these collision point coordinates. An alignment matrix is ​​calculated using the center coordinates of the measuring module before and after secondary clamping, along with the coordinates of fixed points. The initial machining code is modified based on the alignment matrix so that the machine tool can accurately machine the workpiece according to the aligned machining code. Through this method, the development approach of this application can effectively solve the workpiece position and orientation alignment problem, improve the alignment speed of secondary clamping, reduce measurement time, and thus significantly reduce the operator's workload.

[0124] Those skilled in the art will understand that, in the above-described method of the specific implementation, the order in which each step is written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0125] To implement the workpiece alignment method for secondary clamping of machine tools as described in the above embodiments, this application proposes a workpiece alignment device for secondary clamping of machine tools. Please refer to [link to details]. Figure 7 , Figure 7 This is a schematic diagram of an embodiment of the workpiece alignment device for secondary clamping of a machine tool provided in this application.

[0126] like Figure 7 As shown, the workpiece alignment device 400 includes an installation module 41, a measurement module 42, a calculation module 43, and a processing module 44. Among them,

[0127] Mounting module 41 is used to mount a trigger-type probe on the machine tool spindle and a measuring module on the workpiece.

[0128] The measurement module 42 is used to control the probe to move to multiple measurement points on the measurement module before and after the second clamping, and to record the coordinates of multiple collision points between the probe and the measurement module.

[0129] The calculation module 43 is used to calculate the center coordinates of the measurement module before and after the secondary clamping using the coordinates of the multiple collision points before and after the secondary clamping; it is also used to calculate the alignment matrix using the center coordinates of the measurement module before and after the secondary clamping and the coordinates of the fixed point.

[0130] The machining module 44 is used to modify the initial machining code based on the alignment matrix, so that the machine tool can perform precise machining on the workpiece according to the aligned machining code.

[0131] To implement the workpiece alignment method for secondary clamping of machine tools as described in the above embodiments, this application also proposes another workpiece alignment device for secondary clamping of machine tools. Please refer to [link to details]. Figure 8 , Figure 8 This is a schematic diagram of another embodiment of the workpiece alignment device for secondary clamping of machine tools provided in this application.

[0132] The workpiece alignment device 500 of this application embodiment includes a processor 51, a memory 52, an input / output device 53, and a bus 54.

[0133] The processor 51, memory 52, and input / output device 53 are connected to the bus 54. The memory 52 stores program data, and the processor 51 is used to execute the program data to implement the workpiece alignment method for secondary clamping of the machine tool as described in the above embodiment.

[0134] In this embodiment, processor 51 can also be referred to as a CPU (Central Processing Unit). Processor 51 may be an integrated circuit chip with signal processing capabilities. Processor 51 can also 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. The general-purpose processor can be a microprocessor, or processor 51 can be any conventional processor.

[0135] This application also provides a computer storage medium, such as Figure 9 As shown, the computer storage medium 600 is used to store program data 61. When the program data 61 is executed by the processor, it is used to implement the workpiece alignment method for secondary clamping of the machine tool as described in the above embodiment.

[0136] This application also provides a computer program product, wherein the computer program product includes a computer program operable to cause a computer to perform the project development method as described in the embodiments of this application. The computer program product can be a software installation package.

[0137] The project development method described in the above embodiments of this application, when implemented as a software functional unit and sold or used as an independent product, can be stored in a device, such as a computer-readable storage medium. Based on this understanding, the technical solution of this application, 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 methods described in the various embodiments of this invention. 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.

[0138] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A workpiece alignment method for secondary clamping of a machine tool, characterized in that, The workpiece alignment method includes: A trigger-type probe is installed on the machine tool spindle, and a measurement module is installed on the workpiece; The probe is controlled to move to multiple measurement points on the measurement module before and after the second clamping, and the coordinates of multiple collision points between the probe and the measurement module are recorded. The center coordinates of the measurement module before and after the secondary clamping are calculated using the coordinates of the multiple collision points before and after the secondary clamping. The alignment matrix is ​​calculated using the center coordinates of the measurement module before and after the secondary clamping. The initial machining code is modified based on the alignment matrix so that the machine tool can perform precise machining on the workpiece according to the aligned machining code. The step of installing the measuring module on the workpiece includes: Three non-collinear standard spheres are mounted on the workpiece; The workpiece coordinate system includes the X-axis, Y-axis, and Z-axis; The method involves controlling the probe to move to multiple measurement points on the measurement module before and after the secondary clamping, and recording the coordinates of multiple collision points between the probe and the measurement module, including: The probe is controlled to move along the positive X-axis, the negative X-axis, the positive Y-axis, and the negative Y-axis respectively, and to collide with the standard ball before and after the second clamping. Lock the coordinates of the plurality of collision points in the workpiece coordinate system; The calculation of the center coordinates of the measurement module before and after the secondary clamping using the coordinates of the multiple collision points before and after the secondary clamping includes: Obtain the coordinates of the four collision points corresponding to each of the three measurement points before the second clamping; A set of coordinate equations for the center of the sphere before secondary clamping is established by using the relationship that the four collision points corresponding to each measurement point are equidistant from the center of the standard sphere. Input the coordinates of the four collision points corresponding to each of the three measurement points before the second clamping into the system of equations for the center of the sphere before the second clamping, and calculate the center coordinates of the standard sphere before the second clamping. Obtain the coordinates of the four collision points corresponding to each of the three measurement points after the second clamping; A set of coordinate equations for the center of the sphere after secondary clamping is established by using the relationship that the four collision points corresponding to each measurement point are equidistant from the center of the standard sphere. Input the coordinates of the four collision points corresponding to each of the three measurement points after the second clamping into the system of equations for the center coordinates of the sphere after the second clamping, and calculate the center coordinates of the standard sphere after the second clamping. The calculation of the alignment matrix using the center coordinates of the measurement module before and after the secondary clamping includes: Obtain the local coordinate system before the second clamping and the local coordinate system after the second clamping; Calculate the first homogeneous transformation matrix between the local coordinate system and the workpiece coordinate system before the second clamping, and calculate the second homogeneous transformation matrix between the local coordinate system and the workpiece coordinate system after the second clamping; Obtain the coordinates of the first fixed point in the local coordinate system of the fixed point marked on the standard ball before the second clamping, and the coordinates of the second fixed point in the local coordinate system of the fixed point after the second clamping; The coordinates of the fixed point in the workpiece coordinate system are calculated using the coordinates of the first fixed point and the coordinates of the second fixed point, respectively. The alignment matrix is ​​calculated based on the coordinates of the fixed point in the workpiece coordinate system, the first homogeneous transformation matrix, and the second homogeneous transformation matrix. The process of obtaining the local coordinate system before and after the secondary clamping includes: Using the center of the standard sphere before and after the second clamping as the origin of the coordinate system, the unit direction from the center of the sphere to a measurement point as the x-axis, the cross product of the unit direction from the center of the sphere to a measurement point and the unit direction from the center of the sphere to another measurement point as the y-axis, and the z-axis obtained by cross product of the x-axis and y-axis, a local coordinate system before and after the second clamping is established.

2. The workpiece alignment method according to claim 1, characterized in that, After installing the trigger-type probe on the machine tool spindle, the process includes: The probe is calibrated using a lever dial indicator so that the ball at the end of the probe coincides with the spindle axis of the machine tool.

3. The workpiece alignment method according to claim 1, characterized in that, The workpiece alignment method further includes: A first plane is established using the center coordinates of the measurement module before the secondary clamping, and the first unit normal vector of the first plane is obtained. A second plane is established using the center coordinates of the measurement module after the second clamping, and the second unit normal vector of the second plane is obtained. The compensation angle of the rotation axis attitude is calculated using the first unit normal vector and the second unit normal vector.

4. The workpiece alignment method according to claim 3, characterized in that, The modification of the initial processing code based on the correction matrix includes: The initial machining code is modified based on the alignment matrix and the compensation angle of the rotation axis posture.

5. A workpiece alignment device for secondary clamping of a machine tool, characterized in that, The workpiece alignment device includes a memory and a processor, wherein the memory is coupled to the processor; The memory is used to store program data, and the processor is used to execute the program data to implement the workpiece alignment method for secondary clamping of a machine tool as described in any one of claims 1 to 4.

6. A computer storage medium, characterized in that, The computer storage medium is used to store program data, which, when executed by the processor, is used to implement the workpiece alignment method for secondary clamping of the machine tool as described in any one of claims 1 to 4.

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