A method for preparing a hard and brittle material curved surface by grinding, a product, a medium and an apparatus

Abstract

The application discloses a hard and brittle material curved surface grinding preparation method, product, medium and equipment, relates to the technical field of ultra-precision machining, and comprises the following steps: acquiring a geometric model of a hard and brittle material curved surface to be machined and an error value of a grinding preparation process; determining three-dimensional coordinates of a tool position contact point in a grinding tool path based on the geometric model; determining a rigid body conversion matrix by adopting a screw theory according to structural parameters of a grinding preparation machine tool; obtaining an ideal grinding motion model of the machine tool based on the three-dimensional coordinates and the rigid body conversion matrix; compensating the ideal grinding motion model according to the error value of the grinding preparation process to obtain a compensated grinding motion model; and completing the preparation of the hard and brittle curved surface by adopting the compensated grinding motion model. The hard and brittle material curved surface grinding preparation method, product, medium and equipment can effectively improve the machining efficiency and machining quality of the hard and brittle material curved surface.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of ultra-precision machining, in particular to a hard and brittle material curved surface grinding preparation method, product, medium and equipment. BACKGROUND

[0002] With the development of electronics, medicine and advanced optical instruments, the demand for ultra-smooth curved surface elements made of hard and brittle materials such as diamond, silicon carbide and sapphire is increasing day by day in today's society. Due to the characteristics of high hardness and great brittleness of such materials, it is difficult to process them, and often ultra-precision grinding process needs to be used for preparation. In the grinding preparation process, due to rapid wear of the grinding wheel, a large surface error is very easy to occur, and the falling abrasive is also easy to scratch the processed surface, thereby affecting the processing efficiency and processing quality of the element. SUMMARY

[0003] The purpose of the application is to provide a hard and brittle material curved surface grinding preparation method, product, medium and equipment, which can effectively improve the processing efficiency and processing quality of the hard and brittle material curved surface.

[0004] To achieve the above purpose, the application provides the following solutions.

[0005] In a first aspect, the application provides a hard and brittle material curved surface grinding preparation method, comprising:

[0006] obtaining a geometric model of a hard and brittle material curved surface to be processed and an error value of a grinding preparation process; the error value of the grinding preparation process includes a motion error value of a grinding preparation machine tool, an installation error value of the grinding preparation machine tool and a real-time wear error value of a grinding wheel;

[0007] determining a three-dimensional coordinate of a tool position contact point in a grinding tool path based on the geometric model;

[0008] determining a rigid body conversion matrix by using the screw theory according to a structure parameter of the grinding preparation machine tool; the structure parameter includes a position coordinate of each axis of the grinding preparation machine tool relative to a basic coordinate system and a corresponding motion stroke;

[0009] obtaining an ideal grinding motion model of the machine tool based on the three-dimensional coordinate and the rigid body conversion matrix;

[0010] compensating the ideal grinding motion model according to the error value of the grinding preparation process to obtain a compensated grinding motion model;

[0011] completing the preparation of the hard and brittle curved surface by using the compensated grinding motion model.

[0012] Optionally, the obtaining of the geometric model of the hard and brittle material curved surface to be processed and the error value of the grinding preparation process specifically includes:

[0013] Obtain the geometric model of the hard and brittle material surface to be processed by UG software; measure the motion error value of the grinding preparation machine tool and the installation error value of the grinding preparation machine tool by a laser interferometer or a laser displacement sensor; and measure the real-time wear error value of the grinding wheel by a line laser.

[0014] Optionally, the method further comprises:

[0015] Outputting the grinding tool path of the hard and brittle material surface to be processed based on the geometric model and saving the grinding tool path as a text format file;

[0016] Inputting the grinding tool path into MATLAB software, and identifying the three-dimensional coordinates of the tool point in the grinding tool path by a keyword.

[0017] Optionally, the grinding preparation machine tool is a six-axis machine tool, comprising an X-axis, a Y-axis, a Z-axis, a U-axis, an A-axis and a W-axis; the U-axis and the Z-axis are used for positioning the hard and brittle material surface to be processed; the hard and brittle material surface to be processed is moved in the Y-axis direction for error compensation; the hard and brittle material surface to be processed is rotated in the A-axis and W-axis directions for feeding; and the grinding wheel is swung in the X-axis direction for grinding.

[0018] Optionally, the method further comprises:

[0019] According to the structural parameters of the grinding preparation machine tool, a screw theory is used to determine a rigid body conversion matrix.

[0020] According to the structural parameters of the grinding preparation machine tool, a grinding wheel coordinate system, a workpiece coordinate system and a basic coordinate system are established. wherein g rn (θ1,θ2…θ n ) is a rigid body conversion matrix of the nth axis of the grinding preparation machine tool relative to the basic coordinate system [g m (0)], n = 1, 2, …, 6; is a homogeneous transformation matrix corresponding to the nth axis of the grinding preparation machine tool; is a rigid body motion screw of the nth axis of the grinding preparation machine tool; and n is a motion displacement of the nth axis of the grinding preparation machine tool.

[0021] Optionally, the method further comprises:

[0022] The three-dimensional coordinates are substituted into the rigid body conversion matrix by inverse kinematics planning, and an ideal grinding motion model of the machine tool is constructed. wherein, [g bt (0)] is a workpiece coordinate system in an ideal state; bw (0)] -1 is an inverse of a grinding wheel coordinate system [g bw (0)] in an ideal state; is a homogeneous transformation matrix corresponding to an A-axis in an ideal state; is a homogeneous transformation matrix corresponding to a U-axis in an ideal state; is a homogeneous transformation matrix corresponding to a W-axis in an ideal state; is a homogeneous transformation matrix corresponding to a Y-axis in an ideal state; is a homogeneous transformation matrix corresponding to an X-axis in an ideal state; is a homogeneous transformation matrix corresponding to a Z-axis in an ideal state.

[0023] Optionally, an expression of the compensated grinding motion model is wherein, [g bt_cps (0)] is a workpiece coordinate system after compensation; is a motion matrix corresponding to an A-axis after compensation; is a motion matrix corresponding to a U-axis after compensation; is a motion matrix corresponding to a W-axis after compensation; is a motion matrix corresponding to a Y-axis after compensation; is a motion matrix corresponding to an X-axis after compensation; is a motion matrix corresponding to a Z-axis after compensation.

[0024] In a second aspect, the present application provides a computer program product, comprising a computer program which, when executed by a processor, implements the hard and brittle material curved surface grinding preparation method.

[0025] In a third aspect, the present application provides a computer readable storage medium, having a computer program stored thereon, which, when executed by a processor, implements the hard and brittle material curved surface grinding preparation method.

[0026] In a fourth aspect, the present application provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the hard and brittle material curved surface grinding preparation method.

[0027] According to the embodiments provided in the present application, the following technical effects are disclosed:

[0028] The application provides a hard and brittle material curved surface grinding preparation method, a product, a medium and equipment, a geometric model of a hard and brittle material curved surface to be processed is established, three-dimensional coordinates of tool position touch points in a grinding tool path are acquired, and a kinematic model of a machine tool is constructed, so that an ideal grinding motion model is obtained; subsequently, considering motion error values of the grinding preparation machine tool, installation error values and real-time wear error values of a grinding wheel, the ideal grinding motion model is compensated based on the error values, and a compensated grinding motion model is obtained. The application adopts the compensated grinding motion model obtained by the hard and brittle material curved surface grinding motion planning method based on error compensation for the ultra-precision grinding processing of the hard and brittle material, and can effectively improve the processing efficiency and processing quality of the hard and brittle material curved surface. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0030] Figure 1 A hard and brittle material curved surface grinding preparation method flowchart is provided for the present application.

[0031] Figure 2 A hard and brittle material curved surface structure schematic diagram is provided for the present application.

[0032] Figure 3 A three-dimensional coordinate acquisition flowchart of tool position touch points in a grinding tool path is provided for the present application.

[0033] Figure 4 A grinding preparation machine tool structure schematic diagram is provided for the present application.

[0034] Figure 5 A grinding process schematic diagram is provided for the present application.

[0035] Figure 6 A comparison diagram of tool position touch points in an uncompensated grinding tool path and tool position touch points in an ideal grinding tool path is provided for the present application.

[0036] Figure 7 A comparison diagram of tool position touch points in a compensated grinding tool path and tool position touch points in an ideal grinding tool path is provided for the present application.

[0037] Figure 8 A sapphire curved surface part processing diagram is provided for the present application. DETAILED DESCRIPTION

[0038] 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 some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1 As shown, this application discloses a method for preparing a curved surface of a hard and brittle material by grinding, comprising:

[0041] The curved surface (curved part) of the hard and brittle material to be processed includes convex curved surface structures such as spherical surfaces, aspherical surfaces, and quadratic surfaces. This application uses... Figure 2 The method for preparing curved surfaces of hard and brittle materials by grinding is specifically described using the curved surface part shown as an example.

[0042] Step 1: Obtain the geometric model of the surface of the hard and brittle material to be processed and the error value of the grinding preparation process.

[0043] Specifically, this application establishes a model using common 3D software such as UG. Figure 2 The geometric model shown is of the surface of the hard and brittle material to be processed. This geometric model is subsequently used to directly output the grinding toolpath for the surface of the hard and brittle material. The grinding preparation method for hard and brittle material surfaces in this application is mainly based on an error-compensated motion planning method for grinding hard and brittle material surfaces. The error values ​​involved in the grinding preparation process include the motion error value of the grinding preparation machine tool, the installation error value of the grinding preparation machine tool, and the real-time wear error value of the grinding wheel. This application obtains the motion error value and the installation error value of the grinding preparation machine tool by measuring with a laser interferometer or a laser displacement sensor, and obtains the real-time wear error value of the grinding wheel by line laser measurement.

[0044] Step 2: Determine the three-dimensional coordinates of the tool position contact point in the grinding toolpath based on the geometric model.

[0045] Firstly, the tool position contact points of the hard and brittle material surface to be processed under the general three-axis milling machine tool are directly output based on the geometric model of the hard and brittle material surface to be processed obtained in step 1, that is, the grinding tool path (grinding tool path NC code) is directly output. Then the grinding tool path NC code is saved as a text file readable and writable by MATLAB software, and the three-dimensional coordinates of the tool position contact points in the grinding tool path are obtained through keyword recognition by MATLAB software. Specifically, keyword recognition includes key character positioning and coordinate point extraction: set X, Y, Z characters in G code as key characters, then extract characters in G code file one by one, and determine whether it is a keyword, if so, the next character is extracted, that is, the coordinate point corresponding to the key character. Thus the obtained grinding tool path is converted into the three-dimensional coordinates of the tool position contact points in the grinding tool path, and saved as X, Y, Z vector coordinates, which are coordinates in the Cartesian coordinate system. In subsequent operations, it needs to be converted into the motion coordinates of the following six-axis machine tool through rigid body motion transformation. The specific process of obtaining the three-dimensional coordinates of the tool position contact points in the grinding tool path is shown in Figure 3 .

[0046] Step 3: According to the structural parameters of the grinding preparation machine tool, the rigid body conversion matrix is determined by using the screw theory.

[0047] The grinding process of the hard and brittle material surface to be processed in the present application is completed by using the simple cylindrical grinding wheel end surface part, and the grinding preparation machine tool used is a six-axis machine tool including X, Y, Z, U, A and W six motion axes (axis), the structural diagram of which is shown in Figure 4 , including tool chain and workpiece chain. Among them, the tool chain is composed of X axis and Z axis; the workpiece chain is composed of Y axis, W axis, U axis and A axis, Y axis is installed on the bed of the six-axis machine tool, W axis is installed vertically on Y axis, U axis is installed vertically on W axis, A axis is installed on U axis and the hard and brittle material surface to be processed is installed on A axis. Based on the connection relationship, the specific motion process of the hard and brittle material surface to be processed is as follows: the hard and brittle material surface to be processed is positioned by U axis and Z axis, Y axis is used for surface error compensation, the hard and brittle material surface to be processed can move through two rotation directions of A axis and W axis to form the feed generation surface structure. The swing grinding is formed by the reciprocating motion of X axis in the tangent direction of the surface to ensure that the entire end surface of the grinding wheel participates in the surface machining and reduces the influence of grinding wheel wear on the surface machining precision and quality. That is, the swing grinding motion of the hard and brittle material surface to be processed is positioned by U axis and Z axis, Y axis is used for surface error compensation, A axis and W axis are used for workpiece feeding to form the surface structure, and X axis is used for grinding wheel swing grinding. The specific grinding process is shown in Figure 5 . Therefore, the above-mentioned structural parameters include the position coordinates of each axis of the grinding preparation machine tool relative to the basic coordinate system and the corresponding motion stroke.

[0048] After obtaining the aforementioned structural parameters, this application uses spinor theory to perform rigid body motion transformation based on the actual structural parameters of the grinding preparation machine tool to obtain the rigid body transformation matrix. Specifically, firstly, according to the factory drawings of the grinding preparation machine tool, the grinding wheel coordinate system (tool coordinate system), workpiece coordinate system, and basic coordinate system of the grinding preparation machine tool are established. Among them, the origin of the basic coordinate system is the zero point of the machine tool's mechanical coordinates, that is, the dimensional reference during the installation process of each motion axis.

[0049] Specifically, the matrix used to transform the workpiece coordinate system to the fundamental coordinate system using spinor theory is the rigid body transformation matrix:

[0050]

[0051] In the formula, [g m [0] is the basic coordinate system, which can be represented as:

[0052]

[0053] In the formula, g rn (θ1,θ2…θ n ) represents the nth axis of a six-axis machine tool relative to the fundamental coordinate system [g m The rigid body transformation matrix (0) is given by n = 1, 2, ..., 6, which correspond to the X-axis, Y-axis, Z-axis, U-axis, A-axis, and W-axis, respectively. If the nth axis is the axis where the workpiece is located, it is the matrix for transforming the workpiece coordinate system to the basic coordinate system. If the nth axis is the axis where the grinding wheel is located, it is the matrix for transforming the grinding wheel coordinate system to the basic coordinate system. The axes where the workpiece is located include the U-axis, A-axis, and W-axis, and the axes where the grinding wheel is located include the X-axis, Y-axis, and Z-axis. 3×3 It is a 3×3 identity matrix; θ n This refers to the motion command, or motion displacement setting, for the nth axis of a six-axis machine tool. The positional values ​​of each motion axis can be collectively referred to as θ. When the nth axis is the W axis, the angular displacement (motion displacement) of the W axis is θ. w The unit is rad. When the nth axis is axis A, the angular displacement (motion displacement) of axis A is θ. A The unit is rad. When the nth axis is the X-axis, the displacement of the X-axis is x; when the nth axis is the Y-axis, the displacement of the Y-axis is y; when the nth axis is the Z-axis, the displacement of the Z-axis is z; when the nth axis is the U-axis, the displacement of the U-axis is u; when the basic coordinate system [g m (0)] When established at the machine tool's mechanical zero point, t0 is the zero vector, and when the basic coordinate system [g m (0)] When established at other points on the machine tool, t0 is a column vector composed of the mechanical coordinate values ​​of the X-axis, Y-axis and Z-axis of the six-axis machine tool in the basic coordinate system; For the unified description of the homogeneous transformation matrix corresponding to each motion axis of the six-axis machine tool, including and the like, which can be specifically expressed as:

[0054]

[0055] In the formula, I is the abbreviation of the above I 3×3 , is the screw motion of a rigid body, and its expression is:

[0056]

[0057] ν = -ω × q + hω,‖ω‖ = 1,θ≠0 (5)

[0058] In the formula, ω is the unit vector of the motion axis of the rotation shaft (A axis and W axis), is the skew-symmetric matrix of ω; q is the coordinates of the motion axis in the base coordinate system (obtained from the factory machine tool drawing or related data); h is the pitch of the screw motion; ‖‖ represents the norm.

[0059] Step 4: obtaining an ideal grinding motion model of the machine tool based on the three-dimensional coordinates and the rigid body transformation matrix.

[0060] By inverse kinematics planning, the three-dimensional coordinates of the curved surface part are substituted into the rigid body transformation matrix obtained in step 3 to obtain an ideal grinding motion model of the machine tool, i.e. an ideal grinding motion model under the action of no error.

[0061] For the six-axis machine tool of the present application, under the condition of not considering error, the ideal motion of the grinding wheel to the workpiece, i.e. the ideal grinding motion model g wt _ ideal (x,y,z,u,θ w ,θ A ) can be defined as:

[0062]

[0063] In the formula, [g bt (0)] is the workpiece coordinate system in the ideal state, [g bw (0)] -1 is the inverse of the grinding wheel coordinate system [g bw (0)] in the ideal state, and the relationship between the two and the base coordinate system [g m (0)] can also be obtained through formula (1), i.e. formula (1) is a general formula, and the matrix for converting the workpiece coordinate system to the base coordinate system and the matrix for converting the grinding wheel coordinate system to the base coordinate system can also be obtained through formula (1), and for all motion systems, the formula can be expressed in a general manner; (0) represents the coordinate origin. is a homogeneous transformation matrix corresponding to the A-axis in the ideal state (ideal motion matrix) ; is a homogeneous transformation matrix corresponding to the U-axis in the ideal state; is a homogeneous transformation matrix corresponding to the W-axis in the ideal state; is a homogeneous transformation matrix corresponding to the Y-axis in the ideal state; is a homogeneous transformation matrix corresponding to the X-axis in the ideal state; is a homogeneous transformation matrix corresponding to the Z-axis in the ideal state. and are rigid body motion screws of the A-axis, the U-axis, the W-axis, the Y-axis, the X-axis and the Z-axis in the ideal state, respectively, and are referred to as rigid body ideal motion screws. Ai , ui, θ wi , yi, xi and zi are motion displacement amounts of the A-axis, the U-axis, the W-axis, the Y-axis, the X-axis and the Z-axis in the ideal state.

[0064] Step 5: compensating the ideal grinding motion model according to the error value of the grinding preparation process to obtain a compensated grinding motion model.

[0065] Considering the motion error of each motion axis of the machine tool, the installation error of the motion axis and the real-time wear amount change of the grinding wheel in the grinding process, the machine tool motion error and the real-time wear amount of the grinding wheel are compensated into the grinding tool path through forward motion planning, that is, the machine tool motion error and the real-time wear amount of the grinding wheel are substituted into the ideal grinding motion model g wt _ ideal (x,y,z,u,θ w ,θ A ) to obtain a compensated grinding motion model containing machine tool error and grinding wheel wear amount.

[0066] Through machine tool motion accuracy measurement and grinding wheel wear amount measurement, a motion error, installation error and wear error compensation matrix is established, that is, error compensation is performed, and the ideal grinding motion model is brought in to obtain a compensated grinding motion model, which is as follows:

[0067] Taking the rotary axis A as an example, considering the influence of installation error and motion error, the actual motion can be represented as θ A is the motion command of the rotary axis A, and the corresponding installation error can be represented as The motion error can be represented as The geometric error is measured using a laser interferometer, and according to the laser interference measurement principle, the error elements obtained are defined in the workpiece coordinate system, so the error compensation matrix should be right multiplied by the ideal motion matrix of the rotary axis A wherein is a rigid body ideal motion screw.

[0068]

[0069] wherein lrt equals 1 represents left multiplication and equals 0 represents right multiplication, depending on the measuring instrument.

[0070] The actual motion model of the six-axis machine tool can be expressed as g wt _ actual (x,y,z,u,θ w ,θ A ), and the specific derivation process is as follows.

[0071]

[0072] wherein [gbt_actual(0)] is the actual workpiece coordinate system; is the real-time grinding wheel wear amount; is the actual motion matrix corresponding to the A-axis; is the actual motion matrix corresponding to the U-axis; is the actual motion matrix corresponding to the W-axis; is the actual motion matrix corresponding to the Y-axis; is the actual motion matrix corresponding to the X-axis; is the actual motion matrix corresponding to the Z-axis. are the rigid body motion screw quantities of the actual A-axis, U-axis, W-axis, Y-axis, X-axis and Z-axis, respectively.

[0073] The ideal tool position and the actual tool position obtained according to the ideal grinding motion model and the actual motion model are compared as shown in Figure 6 . It can be seen from Figure 6 that the motion error contained in the actual motion model g wt _ actual (x,y,z,u,θ w ,θ A ) will cause the grinding tool path to deviate from the ideal tool path. Therefore, a motion error, installation error and grinding wheel wear amount compensation matrix is established, and the machine tool motion error is compensated by installation error compensation and real-time grinding wheel wear amount compensation , and then substituted into the ideal grinding motion model. The final motion transformation (compensated grinding motion model) of the machine tool can be expressed as g wt _ cps (x,y,z,u,θ w ,θ A ), and the specific calculation process is as follows.

[0074]

[0075] wherein, [g bt_cps is the actual workpiece coordinate system after compensation; is the motion matrix of the A-axis after compensation, i.e., the actual tool position is the tool position after compensation; is the motion matrix of the A-axis after compensation; is the motion matrix of the U-axis after compensation; is the motion matrix of the W-axis after compensation; is the motion matrix of the Y-axis after compensation; is the motion matrix of the X-axis after compensation; is the motion matrix of the Z-axis after compensation. and are rigid body motion screw quantities of the A-axis, U-axis, W-axis, Y-axis, X-axis and Z-axis after compensation, respectively; θ Ac , uc, θ wc , yc, xc and zcare motion displacement quantities of the A-axis, U-axis, W-axis, Y-axis, X-axis and Z-axis after compensation, respectively.

[0076] The comparison between the tool position after compensation and the ideal tool position obtained according to the ideal grinding motion model and the grinding motion model after compensation is shown in Figure 7 , and it can be seen from Figure 7 that the coincidence rate of the tool position after compensation and the ideal tool position is high, which can effectively improve the accuracy of the hard and brittle curved surface preparation.

[0077] Step 6: using the grinding motion model after compensation to complete the preparation of the hard and brittle curved surface.

[0078] After the grinding motion model after compensation is determined through the above steps, the grinding motion model after compensation is used to complete the preparation of the hard and brittle curved surface, which can effectively improve the processing efficiency and processing quality of the hard and brittle material curved surface. As a specific embodiment, the sapphire curved surface part is processed by using the hard and brittle material curved surface grinding preparation method of the present application, and the appearance of the sapphire curved surface part obtained by grinding is shown in Figure 8 .

[0079] In some embodiments, the present application also provides a computer program product comprising a computer program which, when executed by a processor, implements the hard and brittle material curved surface grinding preparation method.

[0080] In some embodiments, the present application also provides a computer readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the hard and brittle material curved surface grinding preparation method.

[0081] In some embodiments, the application also provides a computer device comprising a processor, a memory, an input / output interface (I / O), a communication interface, and a computer program stored in the memory and executable on the processor, the processor executing the computer program to implement the hard brittle material curved surface grinding preparation method.

[0082] The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The database of the computer device is configured to store to-be-processed transactions. The input / output interface of the computer device is configured to exchange information between the processor and external devices. The communication interface of the computer device is configured to communicate with external terminals through a network connection. The computer program is executed by the processor to implement the hard brittle material curved surface grinding preparation method.

[0083] It should be noted that the object information (including but not limited to object device information, object personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the object or fully authorized by all parties, and the collection, use and processing of related data need to comply with relevant laws, regulations and standards of relevant countries and regions.

[0084] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ReadOnly Memory, ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive random access memory (Resistive Random Access Memory, ReRAM), magnetoresistive random access memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric memory (Ferroelectric Random Access Memory, FRAM), phase change memory (Phase Change Memory, PCM), graphene memory, etc. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0085] Any combination of the technical features of the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0086] The principles and implementation modes of the present application are described by using specific examples in the present application. The above embodiments are only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In conclusion, the content of the present application should not be understood as a limitation.

Claims

1. A method for preparing curved surfaces of hard and brittle materials by grinding, characterized in that, include: Obtain the geometric model of the surface of the hard and brittle material to be processed and the error value of the grinding preparation process; the error value of the grinding preparation process includes the motion error value of the grinding preparation machine tool, the installation error value of the grinding preparation machine tool, and the real-time wear error value of the grinding wheel; The three-dimensional coordinates of the tool position contact point in the grinding toolpath are determined based on the geometric model. Based on the structural parameters of the grinding and preparation machine tool, the rigid body transformation matrix is ​​determined using spinor theory; the structural parameters include the position coordinates of each axis of the grinding and preparation machine tool relative to the basic coordinate system and the corresponding motion stroke. Based on the three-dimensional coordinates and the rigid body transformation matrix, an ideal grinding motion model of the machine tool is obtained; The ideal grinding motion model is compensated based on the error value of the grinding preparation process to obtain the compensated grinding motion model; The hard and brittle curved surface was prepared using the compensated grinding motion model.

2. The method for preparing curved surfaces of hard and brittle materials by grinding according to claim 1, characterized in that, The acquisition of the geometric model of the surface of the hard and brittle material to be processed and the error values ​​of the grinding preparation process specifically include: The geometric model of the surface of the hard and brittle material to be processed is obtained by using UG software; the motion error value and installation error value of the grinding preparation machine tool are measured by using a laser interferometer or laser displacement sensor; and the real-time wear error value of the grinding wheel is obtained by using line laser measurement.

3. The method for preparing curved surfaces of hard and brittle materials by grinding according to claim 1, characterized in that, The determination of the three-dimensional coordinates of the tool position contact point in the grinding toolpath based on the geometric model specifically includes: The grinding toolpath of the hard and brittle material surface to be processed is output through the geometric model and saved as a text file; The grinding toolpath is input into MATLAB software, and the three-dimensional coordinates of the tool position contact points in the grinding toolpath are obtained by keyword recognition.

4. The method for preparing curved surfaces of hard and brittle materials by grinding according to claim 1, characterized in that, The grinding preparation machine tool is a six-axis machine tool, including X-axis, Y-axis, Z-axis, U-axis, A-axis and W-axis; wherein, the U-axis and Z-axis are used to position the hard and brittle material surface to be processed; the hard and brittle material surface to be processed is compensated for error by moving in the Y-axis direction; the hard and brittle material surface to be processed is fed by rotating in the A-axis and W-axis directions; the grinding wheel is ground by oscillating in the X-axis direction.

5. The method for preparing curved surfaces of hard and brittle materials by grinding according to claim 4, characterized in that, The rigid body transformation matrix is ​​determined using spinor theory based on the structural parameters of the grinding machine tool, specifically including: Based on the structural parameters of the grinding preparation machine tool, the grinding wheel coordinate system, the workpiece coordinate system, and the basic coordinate system are established respectively. Based on the grinding wheel coordinate system, workpiece coordinate system, and fundamental coordinate system, the rigid body transformation matrix is ​​obtained through spinor theory. Among them, g rn (θ1,θ2…θ n ) for grinding preparation machine tool n-th axis relative to the basic coordinate system [g m The rigid body transformation matrix of [(0)], n = 1, 2, ..., 6; Prepare the homogeneous transformation matrix corresponding to the nth axis of the machine tool for grinding; The helical amount of rigid body motion of the nth axis of the grinding preparation machine tool; θ n The motion displacement of the nth axis of the grinding preparation machine tool.

6. The method for preparing curved surfaces of hard and brittle materials by grinding according to claim 5, characterized in that, The ideal grinding motion model of the machine tool obtained based on the three-dimensional coordinates and the rigid body transformation matrix specifically includes: By substituting the three-dimensional coordinates into the rigid body transformation matrix through inverse kinematics programming, an ideal grinding motion model of the machine tool is constructed. Among them, [g bt [0] represents the workpiece coordinate system under ideal conditions; [g] bw (0)] -1 For the ideal grinding wheel coordinate system [g] bw The inverse of (0)]; This is the homogeneous transformation matrix corresponding to the A-axis under ideal conditions; This is the homogeneous transformation matrix corresponding to the U-axis under ideal conditions; This is the homogeneous transformation matrix corresponding to the W-axis under ideal conditions; This is the homogeneous transformation matrix corresponding to the Y-axis under ideal conditions; This is the homogeneous transformation matrix corresponding to the X-axis under ideal conditions; This is the homogeneous transformation matrix corresponding to the Z-axis under ideal conditions.

7. The method for preparing curved surfaces of hard and brittle materials by grinding according to claim 6, characterized in that, The expression for the compensated grinding motion model is as follows: Among them, [g bt_cps [0] represents the compensated workpiece coordinate system; The motion matrix corresponding to the compensated A-axis; The motion matrix corresponding to the compensated U-axis; The motion matrix corresponding to the compensated W-axis; The motion matrix corresponding to the compensated Y-axis; The motion matrix corresponding to the compensated X-axis; This is the motion matrix corresponding to the compensated Z-axis.

8. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the method for preparing hard and brittle material surfaces by grinding as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the method for preparing hard and brittle material surfaces by grinding as described in any one of claims 1-7.

10. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the method for preparing a hard and brittle material surface by grinding according to any one of claims 1-7.

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