Machine tool straightness error calculation method and system based on the deformation amount of linear guide rails

Abstract

The present invention discloses a method and system for calculating the straightness error of a machine tool based on the deformation of a linear guide rail, which relates to the technical field of machine tool straightness accuracy and straightness error evaluation. The method includes the steps of: obtaining the machining parameters of the linear guide rail and the bed mounting surface during the installation of the machine tool; determining the contact point position between the linear guide rail and the bed mounting surface and the magnitude of the normal supporting force in combination with the force balance condition of the linear guide rail; calculating the deformation of the linear guide rail caused by its own weight, bolt pre-tightening force and normal supporting force; calculating the offset value of the reference surface of the linear guide rail; and calculating the actual straightness of the linear feed axis based on the relationship between the linear guide rail deformation and straightness. The method of the present invention makes the calculation process more in line with the actual assembly of the linear guide rail, and can solve problems such as idealization and limitation existing in the existing mathematical model.

Description

Technical Field

[0001] The present invention relates to the technical field of linear accuracy and straightness error evaluation of machine tools, and particularly to a method and system for calculating the straightness error of a machine tool based on the deformation amount of a linear guide rail. Background Technique

[0002] The statements in this part merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] The straightness error of the linear feed axis of a machine tool mainly originates from the assembly process of the linear guide rail. This error will cause the position deviation of the tool or workpiece during machining, thereby affecting the geometric accuracy and overall quality of the machined surface. Especially when the linear guide rail bears external vertical loads such as bolt pre-tightening force and normal supporting force, the problem of straightness error is more prominent, which has a significant impact on the linear accuracy of the machine tool. Therefore, in order to accurately evaluate the linear accuracy of the machine tool and improve the assembly accuracy, it is urgent to explore a more realistic method for calculating the straightness error. These studies will provide important theoretical support and practical guidance for the design optimization of machine tools and linear guide rails, manufacturing error control, and subsequent installation and adjustment.

[0004] Currently, the measurement or calculation methods of straightness error mainly include direct measurement methods and artificial intelligence algorithm prediction methods. The direct measurement method uses special measuring instruments such as laser interferometers, spirit levels or autocollimators to directly measure the straightness error of the machine tool. However, these measuring instruments are easily affected by environmental factors such as temperature, humidity, air flow, and ground unevenness, thus affecting the accuracy of the measurement results. At the same time, some measuring instruments may only be applicable to specific ranges or specific types of measurements, and accurate results may not be obtained for measurements outside their ranges. The artificial intelligence algorithm prediction method constructs a prediction model and uses a large amount of straightness error measurement data to train and optimize the model, thereby realizing the prediction of the straightness error. This method largely depends on the quality and accuracy of the input data. If there are problems such as noise, outliers or missing values in the input data, it may affect the training effect and prediction accuracy of the model. In addition, some artificial intelligence algorithms, especially deep learning models, often have a high degree of non-linearity and complexity, which makes them difficult to interpret and debug, and have poor interpretability. When the model prediction is incorrect, it may be difficult to determine the cause of the error and make improvements.

[0005] Based on the deficiencies of the above methods, the mathematical model method shows high rationality and robustness. This method mainly based on geometric principles and error analysis, accurately calculates the straightness error by establishing mathematical models and formulas. However, this method is based on a series of assumptions and ideal conditions, and in practical applications, these conditions may be difficult to fully meet, resulting in a deviation between the derivation result and the actual situation.

[0006] Therefore, how to overcome the idealization and limitation defects in the existing mathematical models and achieve the accurate measurement of the straightness error of the machine tool linear feed axis has become an urgent problem to be solved in the existing technology. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a method and system for calculating the straightness error of a machine tool based on the deformation of a linear guide rail. Based on the existing mathematical model method, the influence of external loads such as bolt pre-tightening force, self-weight, and normal supporting force on the deformation and straightness error of the linear guide rail is comprehensively considered, making the calculation process more in line with the actual assembly of the linear guide rail, and solving the problems of idealization and limitation existing in the existing mathematical models.

[0008] To achieve the above purpose, the present invention is implemented through the following technical solutions:

[0009] The first aspect of the present invention provides a method for calculating the straightness error of a machine tool based on the deformation of a linear guide rail, including the following steps:

[0010] Obtain the machining parameters of the linear guide rail and the bed mounting surface during the machine tool installation process, where the machining parameters of the linear guide rail and the bed mounting surface include the contour curves with machining errors of the linear guide rail and the bed mounting surface, the self-weight of the linear guide rail, and the bolt pre-tightening torque;

[0011] According to the contour curves with machining errors of the linear guide rail and the bed mounting surface, combined with the force balance condition of the linear guide rail, determine the contact point position between the linear guide rail and the bed mounting surface and the magnitude of the normal supporting force;

[0012] Calculate the deformation of the linear guide rail caused by the self-weight, bolt pre-tightening force, and normal supporting force of the linear guide rail;

[0013] Calculate the offset value of the reference surface of the linear guide rail according to the deformation of the linear guide rail;

[0014] Based on the relationship between the deformation of the linear guide rail and the straightness, calculate the actual straightness of the linear feed axis according to the offset value of the reference surface of the linear guide rail.

[0015] Further, the specific steps for obtaining the contour curves with machining errors of the linear guide rail and the bed mounting surface are as follows:

[0016] Use a measuring instrument to measure the machining errors of the linear guide rail or the bed mounting surface during the machining process;

[0017] Draw the contour curves with machining errors according to the changes of the machining errors in the length direction.

[0018] Further, the force balance condition of the linear guide rail specifically refers to:

[0019] The vector sum of the bolt pre-tightening force, the self-weight of the linear guide rail, and the normal support force acting on the linear guide rail is zero; in addition to force balance, the moments of the linear guide rail must also be balanced, that is, the sum of the moments of the linear guide rail about any rotation axis is zero.

[0020] Further, the specific steps for determining the contact point position between the linear guide rail and the bed mounting surface are as follows:

[0021] Determine two contact points between the linear guide rail and the bed mounting surface;

[0022] Calculate the horizontal coordinates of the two contact points or the horizontal distance length between them and the left end face of the linear guide rail as the contact point position between the linear guide rail and the bed mounting surface.

[0023] Further, the specific steps for calculating the deformation of the linear guide rail caused by its self-weight, bolt pre-tightening force, and normal support force are as follows:

[0024] Based on the design structure and assembly process of the linear feed axis, the linear guide rail is positioned through the mounting bracket, guide rail fixture, and end face;

[0025] Idealize the linear guide rail as a simply supported beam structure;

[0026] Use the bending deflection of the simply supported beam to calculate the deformation of the linear guide rail caused by different types of loads.

[0027] Furthermore, the offset value of the reference plane of the linear guide rail refers to the situation where the bolt pre-tightening force, self-weight, and normal support force acting on the linear guide rail are all in the vertical direction. The movement trajectory of the slider on the linear guide rail will produce an overall upward or downward offset, resulting in the offset value of the reference plane of the linear guide rail relative to the ideal horizontal plane.

[0028] Furthermore, based on the relationship between the deformation and straightness of the linear guide rail, the specific steps for calculating the actual straightness of the linear feed axis according to the offset value of the reference plane of the linear guide rail are as follows:

[0029] The linear guide rail deforms under the action of different loads. The movement trajectory of the slider on the linear guide rail is similar to a sine curve. Regarding the slider as a rigid body, select the deformation at the position of the maximum error of the slider to calculate the straightness error;

[0030] On the basis of the straightness error, add the offset value of the reference plane of the linear guide rail to obtain the actual straightness error.

[0031] The second aspect of the present invention provides a machine tool straightness error calculation system based on the deformation of the linear guide rail, including:

[0032] A data acquisition module, configured to acquire the machining parameters of the linear guide and the bed mounting surface during the installation of the machine tool, where the machining parameters of the linear guide and the bed mounting surface include the contour curves of the linear guide and the bed mounting surface with machining errors, the self-weight of the linear guide, and the bolt pre-tightening torque;

[0033] A first data processing module, configured to determine the contact point position and the magnitude of the normal support force between the linear guide and the bed mounting surface according to the contour curves of the linear guide and the bed mounting surface with machining errors, in combination with the force balance condition of the linear guide;

[0034] A second data processing module, configured to calculate the deformation amount of the linear guide caused by the self-weight of the linear guide, the bolt pre-tightening force, and the normal support force;

[0035] An error calculation module, configured to calculate the offset value of the reference surface of the linear guide according to the deformation amount of the linear guide;

[0036] An actual straightness calculation module, configured to calculate the actual straightness of the linear feed axis based on the relationship between the deformation of the linear guide and the straightness, according to the offset value of the reference surface of the linear guide.

[0037] A third aspect of the present invention provides a medium, on which a program is stored, and when the program is executed by a processor, the steps in the method for calculating the straightness error of the machine tool based on the deformation amount of the linear guide as described in the first aspect of the present invention are implemented.

[0038] A fourth aspect of the present invention provides a device, including a memory, a processor, and a program stored on the memory and executable on the processor. When the processor executes the program, the steps in the method for calculating the straightness error of the machine tool based on the deformation amount of the linear guide as described in the first aspect of the present invention are implemented.

[0039] The above one or more technical solutions have the following beneficial effects:

[0040] The present invention discloses a method and system for calculating the straightness error of a machine tool based on the deformation amount of a linear guide, comprehensively considering multiple factors such as the external load on the linear guide and the inherent machining errors of the linear guide-bed mounting surface, and compensating for the offset of the reference surface of the linear guide. The entire calculation process starts from the source of the straightness error, forming a complete transmission chain of manufacturing - loading - deformation - error, so that the calculation result can more accurately simulate and reflect the essence of the actual problem compared with the traditional calculation method, and has higher practicability and reliability, improving the calculation accuracy of the straightness error, and is also more suitable for machine tool manufacturers to refer to in the selection of the bolt pre-tightening strategy of the linear guide.

[0041] Advantages of additional aspects of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0042] The schematic diagrams in the specification, which form a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not unduly limit the present invention.

[0043] Figure 1 is a schematic flow chart of a method for calculating the straightness error of a machine tool based on the deformation amount of a linear guide in the first embodiment of the present invention;

[0044] Figure 2 is a schematic diagram of the force on the linear guide in the first embodiment of the present invention;

[0045] Figure 3 is a schematic diagram of the offset of the reference plane of the linear guide relative to the ideal horizontal plane in the first embodiment of the present invention;

[0046] Figure 4 is a schematic diagram of the relationship between the deformation and the straightness error of the linear guide in the first embodiment of the present invention. Detailed Embodiments

[0047] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0048] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof;

[0049] Embodiment 1:

[0050] The first embodiment of the present invention provides a method for calculating the straightness error of a machine tool based on the deformation amount of a linear guide, as Figure 1 shown, including the following steps:

[0051] S1: Obtain the machining parameters of the linear guide and the bed mounting surface during the installation of the machine tool. Among them, the machining parameters of the linear guide and the bed mounting surface include key parameters such as the contour curves with machining errors of the linear guide and the bed mounting surface, the self-weight of the linear guide, and the bolt pre-tightening torque.

[0052] S11: Measure the machining errors of the linear guide rail or the installation surface of the machine bed during the machining process using measuring instruments.

[0053] In a specific implementation, the linear guide rail and the installation surface of the machine bed will undergo various machining processes, including rough machining, heat treatment, milling, and grinding, etc., thus generating certain machining errors. The machining errors mainly vary along the length direction and are not significant in the width direction. Use measuring instrument equipment including but not limited to coordinate measuring machines, collimators, dial indicators, etc. to measure the machining errors of the linear guide rail or the installation surface of the machine bed, and then obtain a contour curve containing machining errors.

[0054] Use an electronic scale to measure or refer to the manufacturing instructions to obtain the self-weight of the linear guide rail.

[0055] According to the model specifications of the bolts used, refer to the national standard "GB / T 3098.6 - 2023" and production experience to obtain the pre-tightening torque of the bolts for the linear guide rail.

[0056] S12: Draw a contour curve containing machining errors according to the variation of the machining errors along the length direction. And convert the bolt pre-tightening torque into pre-tightening force.

[0057] S121: Place the linear guide rail upside down on the coordinate measuring machine so that its bottom surface faces up. Select multiple measuring points arranged horizontally and linearly on the bottom surface of the linear guide rail, use a probe to measure the position coordinates of these measuring points in the vertical direction, and connect and fit the position coordinates of these measuring points to obtain the contour curve of the linear guide rail containing machining errors. 。

[0058] S122: Use a dial indicator to measure the machining errors of multiple measuring points arranged horizontally and linearly on the installation surface of the machine bed relative to the horizontal plane in sequence, and fit them into a curve to obtain the contour curve of the installation surface of the machine bed containing machining errors. 。

[0059] S123: According to the geometric dimension parameters of the bolts, convert the bolt pre-tightening torque T into pre-tightening force F , and the conversion formula is:

[0060] 。

[0061] Among them, is the nominal diameter of the bolt, is the bolt hole diameter, is the pitch diameter of the thread, is the bearing surface diameter, is the pitch, is the friction coefficient between the bolt head and the connected part, is the thread friction coefficient, is the equivalent friction angle of the thread, is the lead angle of the thread.

[0062] S2: According to the contour curve of the linear guide rail and the bed mounting surface with machining errors, combined with the force balance condition of the linear guide rail, determine the contact point position between the linear guide rail and the bed mounting surface and the magnitude of the normal support force.

[0063] In a specific implementation, determine the force balance condition of the linear guide rail. The vector sum of the bolt pre-tightening force, the self-weight of the linear guide rail, and the normal support force acting on the linear guide rail is zero; in addition to force balance, the moment of the linear guide rail must also be balanced, that is, the sum of the moments of the linear guide rail about any rotation axis is zero.

[0064] Determine the contact point position between the linear guide rail and the bed mounting surface and the magnitude of the normal support force.

[0065] First, determine the two contact points between the linear guide rail and the bed mounting surface. Due to machining errors, the contact between the linear guide rail and the bed mounting surface is not completely fitting, but there are two contact points. Then calculate the horizontal coordinates of the two contact points, and the horizontal distance length between the two contact points and the left end face of the linear guide rail is used as the contact point position between the linear guide rail and the bed mounting surface.

[0066] S21: Horizontally connect the two ends of the guide rail contour curve and the bed mounting surface contour curve together.

[0067] S22: Calculate the horizontal position coordinate of the lowest point of , translate to so that is tangent to at the point. The expression of

[0068] is:

[0069] S23: Compare the magnitudes of and . Among them, is the length of the linear guide rail.

[0070] If , then calculate the horizontal position coordinate of the lowest point of in the interval;

[0071] If , then calculate the horizontal position coordinate of the lowest point of Horizontal position coordinate of the lowest point ;

[0072] S24: With as the rotation center, rotate by degrees to , so that passes through . and The expressions of are:

[0073] .

[0074] .

[0075] S25: Calculate the distance and between .

[0076] If at all positions , it indicates that there is no interference or overlap between the two curves, and the two positions of are the tangent points between the two curves, which are the contact point positions between the linear guide and the bed mounting surface.

[0077] If there exists at a certain position, then calculate the horizontal position coordinate of the minimum value of .

[0078] S26: Compare the magnitudes of and .

[0079] If , then use as the rotation center;

[0080] If , then use as the rotation center;

[0081] Rotate around the rotation center by an angle to , so that passes through , The expression of is:

[0082] .

[0083] S27: Repeat steps S25 and S26 until for all positions between the new curve and . The two positions are the contact point positions between the linear guide rail and the bed mounting surface.

[0084] S28. According to Figure 2 the force condition of the linear guide rail shown, the linear guide rail reaches force balance under the interaction of loads such as bolt pre-tightening force , normal support force and self-weight etc. The force balance relation is:

[0085] .

[0086] Among them, F bi is the bolt pre-tightening force, and are two normal support forces, G is the self-weight of the linear guide rail, is the distance between the i-th bolt hole and the left end face of the linear guide rail, and are the distances between the support points and the left end face of the linear guide rail, is the number of bolts.

[0087] According to the calculations in steps S21 - S28, the magnitudes of the normal support forces and can be obtained.

[0088] S3: Calculate the deformation of the linear guide rail caused by the self-weight, bolt pre-tightening force and normal support force of the linear guide rail.

[0089] S31: Based on the design structure and assembly process of the linear feed axis, the linear guide rail is positioned through the mounting bracket, guide rail fixture and end face. After positioning, the linear guide rail is approximately a simply supported beam structure. Therefore, the linear guide rail is idealized as a simply supported beam structure.

[0090] S32: Idealize the linear guide rail as a simply supported beam structure.

[0091] S33: Use the bending deflection of the simply supported beam to calculate the deformation of the linear guide rail caused by different types of loads.

[0092] S331: The bending deflection caused by each bolt pre-tightening force at a certain position x of the linear guide rail is:

[0093] .

[0094] Among them, is the bending deflection at a certain position x of the linear guide rail caused by each bolt pre-tightening force, E is the elastic modulus of the linear guide rail, I is the moment of inertia of the linear guide rail, and L is the length of the linear guide rail.

[0095] S332: The bending deflection caused by the normal support force at a certain position x on the linear guide rail is:

[0096] .

[0097] Among them, is the bending deflection at a certain position x on the linear guide rail caused by the normal support force, and j = 1, 2.

[0098] S333: Consider the self-weight of the linear guide rail as a uniform load distributed on the linear guide rail ( ), and the bending deflection at a certain position x on the linear guide rail caused by the self-weight of the guide rail is:

[0099] .

[0100] Among them, is the bending deflection at a certain position x on the linear guide rail caused by the self-weight of the guide rail.

[0101] S334: According to the superposition principle of deflections, the total deflection at a certain position x on the linear guide rail caused by the three kinds of loads is:

[0102] .

[0103] Among them, represents the total deflection.

[0104] S335: The final deformation curve of the linear guide rail is:

[0105] .

[0106] Among them, represents the final deformation curve of the linear guide rail, represents the position of the linear guide rail, represents the position serial number of the linear guide rail.

[0107] S4: Calculate the offset value of the reference plane of the linear guide rail according to the deformation amount of the linear guide rail.

[0108] In a specific implementation manner, the offset value of the reference plane of the linear guide rail means that the bolt pre-tightening force, self-weight, and normal support force applied to the linear guide rail are all in the vertical direction. Due to the internal rolling elements, the slider can move along the axis of the linear guide rail. The straightness error of the linear guide rail is generally reflected in the movement trajectory of the slider. The movement trajectory of the slider on the linear guide rail will generate an overall upward or downward offset due to the load deformation of the linear guide rail, as shown in Figure 3 , thus resulting in the offset value of the reference plane of the linear guide rail relative to the ideal horizontal plane:

[0109] 。

[0110] Among them, is the offset value, are several position points selected on the linear guide rail where the deformation amount is located, is the number of selected position points.

[0111] S5: Based on the relationship between the deformation of the linear guide rail and its straightness, calculate the actual straightness of the linear feed axis according to the offset value of the reference surface of the linear guide rail.

[0112] S51: The linear guide rail deforms under the action of different loads, and the movement trajectory of the slider on the linear guide rail is similar to a sine curve, as Figure 4 shown. Regarding the slider as a rigid body, select the deformation at the position with the maximum error of the slider to calculate the straightness error:

[0113]

[0114] Among them, is the straightness error at the position on the linear guide rail, and are respectively the deformation values at the and positions of the linear guide rail.

[0115] S52: Based on the straightness error, add the offset value of the reference surface of the linear guide rail to obtain the actual straightness error:

[0116] 。

[0117] Among them, is the actual straightness error.

[0118] The present invention comprehensively considers the machining errors of the linear guide rail and the bed mounting surface, the bolt pre-tightening force, and the influence of self-weight on the straightness error, making the calculation process more in line with the actual situation, improving the calculation accuracy of the straightness error of the linear feed axis of the machine tool, being conducive to the prediction and evaluation of the linear accuracy of the machine tool, and providing data support for the installation and adjustment of the linear guide rail.

[0119] Embodiment 2:

[0120] The second embodiment of the present invention provides a system for calculating the straightness error of a machine tool based on the deformation amount of a linear guide rail, including:

[0121] A data acquisition module, configured to acquire the machining parameters of the linear guide rail and the bed mounting surface during the installation of the machine tool, wherein the machining parameters of the linear guide rail and the bed mounting surface include the contour curves with machining errors of the linear guide rail and the bed mounting surface, the self-weight of the linear guide rail, and the bolt pre-tightening torque;

[0122] The first data processing module is configured to determine the contact point position between the linear guide rail and the bed mounting surface and the magnitude of the normal supporting force according to the contour curve with machining errors of the linear guide rail and the bed mounting surface, in combination with the force balance condition of the linear guide rail.

[0123] The second data processing module is configured to calculate the deformation amount of the linear guide rail caused by the self-weight of the linear guide rail, the bolt pre-tightening force, and the normal supporting force.

[0124] The error calculation module is configured to calculate the offset value of the reference surface of the linear guide rail according to the deformation amount of the linear guide rail.

[0125] The actual straightness calculation module is configured to calculate the actual straightness of the linear feed axis based on the relationship between the deformation of the linear guide rail and the straightness, according to the offset value of the reference surface of the linear guide rail.

[0126] Embodiment III:

[0127] Embodiment III of the present invention provides a medium on which a program is stored, and when the program is executed by a processor, it implements the steps in the method for calculating the straightness error of a machine tool based on the deformation amount of a linear guide rail as described in Embodiment I of the present invention.

[0128] Embodiment IV:

[0129] Embodiment IV of the present invention provides a device, including a memory, a processor, and a program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps in the method for calculating the straightness error of a machine tool based on the deformation amount of a linear guide rail as described in Embodiment I of the present invention.

[0130] The steps involved in the above Embodiments II, III, and IV correspond to those in Method Embodiment I, and the specific implementation manners can be referred to the relevant description part of Embodiment I.

[0131] Those skilled in the art should understand that the above-mentioned modules or steps of the present invention can be implemented by a general-purpose computer device. Optionally, they can be implemented by program codes executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0132] Although the specific implementation manners of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that, based on the technical solutions of the present invention, various modifications or deformations that can be made without creative efforts by those skilled in the art are still within the protection scope of the present invention.

Claims

1. A method for calculating the straightness error of a machine tool based on the deformation of a linear guide rail, characterized in that: The following steps are involved: Obtaining the processing parameters of the linear guide rail and the bed installation surface during the installation of the machine tool, wherein the processing parameters of the linear guide rail and the bed installation surface include the contour curve of the linear guide rail and the bed installation surface containing processing errors, the deadweight of the linear guide rail, and the bolt pre-tightening torque; According to the contour curves containing machining errors of the linear guide and the bed mounting surface, combined with the force balance condition of the linear guide, the contact point position between the linear guide and the bed mounting surface and the normal support force are determined; wherein, the specific steps of determining the contact point position between the linear guide and the bed mounting surface are: determining two contact points between the linear guide and the bed mounting surface; calculating the coordinates of the two contact points in the horizontal direction or the horizontal distance between the left end surface of the linear guide as the contact point position between the linear guide and the bed mounting surface; Calculate the deformation of the linear guide caused by the linear guide's deadweight, bolt preload and normal support force; The offset value of the reference plane of the linear guide is calculated according to the deformation of the linear guide; the offset value of the reference plane of the linear guide refers to the fact that the bolt preload, deadweight and normal support force of the linear guide are all in the vertical direction, and the motion trajectory of the slider on the linear guide will produce an overall upward or downward offset, which will lead to the offset value of the reference plane of the linear guide relative to the ideal horizontal plane; Based on the relationship between linear guide deformation and straightness, the actual straightness of the linear feed axis is calculated according to the offset value of the linear guide reference surface. The specific steps are as follows: The linear guide rail is deformed due to different loads. The motion trajectory of the slider on the linear guide rail is similar to a sine curve. The slider is regarded as a rigid body, and the deformation of the slider at the maximum error position is selected to calculate the straightness error. On the basis of the straightness error, add the offset value of the linear guide reference surface to obtain the actual straightness error.

2. The method for calculating the straightness error of a machine tool based on the deformation of a linear guide rail according to claim 1, characterized in that: The specific steps to obtain the contour curve containing machining errors of the linear guide rail and the bed mounting surface are as follows: Use measuring instruments to measure the machining errors of linear guides or bed mounting surfaces during machining; According to the change of machining error along the length direction, a contour curve containing machining error is drawn.

3. The method for calculating the straightness error of a machine tool based on the deformation of a linear guide rail according to claim 1, characterized in that: The force balance condition of the linear guide specifically refers to: The vector sum of the bolt preload, the linear guide's deadweight, and the normal support force on the linear guide is zero; in addition to force balance, the linear guide's torque must also be balanced, that is, the sum of the linear guide's torque on any rotating axis is zero.

4. The method for calculating the straightness error of a machine tool based on the deformation of a linear guide rail according to claim 1, characterized in that: The specific steps for calculating the deformation of the linear guide caused by the linear guide's deadweight, bolt preload and normal support force are as follows: Based on the design structure and assembly process of the linear feed axis, the linear guide is positioned by mounting brackets, guide fixtures and end faces; Idealize the linear guide as a simply supported beam structure; The bending deflection of a simply supported beam is used to calculate the deformation of a linear guide due to different types of loads.

5. A machine tool straightness error calculation system based on linear guide deformation, characterized in that: include: A data acquisition module is configured to acquire processing parameters of the linear guide rail and the bed mounting surface during the installation of the machine tool, wherein the processing parameters of the linear guide rail and the bed mounting surface include contour curves of the linear guide rail and the bed mounting surface containing processing errors, the deadweight of the linear guide rail, and the bolt pre-tightening torque; The first data processing module is configured to determine the contact point position between the linear guide and the bed mounting surface and the normal support force according to the contour curve containing the machining error of the linear guide and the bed mounting surface, combined with the force balance condition of the linear guide; wherein the specific steps of determining the contact point position between the linear guide and the bed mounting surface are: determining two contact points between the linear guide and the bed mounting surface; calculating the coordinates of the two contact points in the horizontal direction or the horizontal distance between the left end surface of the linear guide as the contact point position between the linear guide and the bed mounting surface; The second data processing module is configured to calculate the deformation of the linear guide rail caused by the deadweight of the linear guide rail, the bolt preload and the normal support force; The error calculation module is configured to calculate the offset value of the reference surface of the linear guide according to the deformation of the linear guide; the offset value of the reference surface of the linear guide refers to the fact that the bolt preload, deadweight and normal support force of the linear guide are all in the vertical direction, and the motion trajectory of the slider on the linear guide will produce an overall upward or downward offset, thereby causing the offset value of the reference surface of the linear guide relative to the ideal horizontal plane; The actual straightness calculation module is configured to calculate the actual straightness of the linear feed axis according to the offset value of the linear guide reference surface based on the relationship between the linear guide deformation and the straightness. The specific steps are as follows: The linear guide rail is deformed due to different loads. The motion trajectory of the slider on the linear guide rail is similar to a sine curve. The slider is regarded as a rigid body, and the deformation of the slider at the maximum error position is selected to calculate the straightness error. On the basis of the straightness error, add the offset value of the linear guide reference surface to obtain the actual straightness error.

6. A computer-readable storage medium, characterized in that: A plurality of instructions are stored therein, and the instructions are suitable for being loaded by a processor of a terminal device and executed in accordance with any one of claims 1 to 4 as a method for calculating the straightness error of a machine tool based on the deformation of a linear guide rail.

7. A terminal device, characterized in that: It includes a processor and a computer-readable storage medium, the processor is used to implement various instructions; the computer-readable storage medium is used to store multiple instructions, and the instructions are suitable for being loaded by the processor and executing the machine tool straightness error calculation method based on the linear guide deformation according to any one of claims 1-4.

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