Method, device and system for positioning workpiece of CNC lathe based on magnetization characteristics

Abstract

The present invention discloses a method, device and system for positioning a workpiece of a CNC lathe based on magnetization characteristics, wherein the method comprises: pre-scanning the surface of the workpiece to be transferred on the workstation, obtaining magnetic field intensity distribution data, and obtaining the best clamping point; processing the magnetic field intensity distribution data to obtain the distribution data of the unstable area on the workpiece surface; performing magnetic torque analysis to obtain the optimal placement angle; selecting a three-point support placement scheme based on the optimal placement angle; performing mechanical simulation analysis to obtain the result of determining the stable state of the workpiece. The technical solution of the present invention realizes active pre-judgment and control of the magnetization state during the placement process by accurately identifying and analyzing the magnetization characteristics of the workpiece surface, effectively avoiding the problem of displacement of the workpiece on the measuring platform due to magnetization, and ensuring the measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring magnetic variables, and in particular to a method, device and system for positioning a workpiece of a CNC lathe based on magnetization characteristics. Background Art

[0002] CNC lathe is an automated processing equipment that controls each moving part through a computer digital control system to achieve precision processing of the workpiece. In modern manufacturing, CNC lathes have developed complex processing capabilities with multi-axis linkage, and can complete a variety of processing processes such as turning and milling. Especially in the processing of precision parts (such as valve cores, bearings, etc.), multiple stations are often required to collaborate to complete different processing tasks. Among them, the measuring station, as a key link in quality control, requires high-precision detection of the size and shape and position accuracy of the workpiece. At the measuring station, the workpiece is usually placed in the V-block of the measuring platform, and the measuring probe contacts the surface of the workpiece from different directions for data collection. To ensure the measurement accuracy, the workpiece must remain in a stable natural placement state and cannot be fixed by strong clamping.

[0003] In actual production, after the workpiece has gone through turning, grinding and other processing procedures, its surface often produces uneven local magnetization. This magnetization phenomenon will cause the workpiece to produce a small displacement or posture change on the measuring platform, especially when the workpiece is transferred from the manipulator to the V-block of the measuring platform, because it is impossible to use a strong clamping method, the workpiece may move slightly under the action of the magnetic force. Although this unexpected displacement is very small, it will directly affect the accuracy of the measurement results in high-precision measurements. Although the existing technology also recognizes the existence of the magnetization problem, it usually adopts a unified demagnetization treatment of the workpiece after processing. However, when the workpiece passes through subsequent links such as robot grasping and transportation, the contact friction with the manipulator gripper and the influence of the environmental magnetic field will cause the surface of the workpiece to re-produce local magnetization. This magnetization effect generated during the transportation process is difficult to solve by unified demagnetization after processing, and it will eventually affect the positioning stability of the workpiece at the measurement station, resulting in reduced measurement accuracy. Summary of the invention

[0004] The main purpose of the present invention is to solve the technical problem in the prior art that a workpiece is displaced at a measuring station due to local magnetization, resulting in reduced measurement accuracy.

[0005] A first aspect of the present invention provides a method for positioning a workpiece of a CNC lathe based on magnetization characteristics, the method comprising:

[0006] Pre-scanning the surface of the workpiece to be transferred on the workstation to obtain magnetic field intensity distribution data on the workpiece surface, and obtaining two optimal clamping points of the workpiece based on the magnetic field intensity distribution data;

[0007] Processing the magnetic field intensity distribution data, determining the average value of the magnetic field intensity of the two best clamping points as a reference value, marking the area where the circumferential magnetic field intensity variation exceeds a preset multiple of the reference value, and obtaining the unstable area distribution data on the workpiece surface;

[0008] Performing magnetic moment analysis on the unstable area distribution data, taking the line connecting the two optimal clamping points as a reference, calculating the synthetic magnetic moment of each circumferential magnetized area of ​​the workpiece, and obtaining the optimal placement angle of the workpiece;

[0009] Based on the optimal placement angle, an area on the workpiece surface where the angle between the line connecting the two optimal clamping points is a preset angle and the magnetic field strength is the smallest is selected as the first contact point, and two points with the smallest magnetic field strength are selected on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece;

[0010] A mechanical simulation analysis is performed on the three-point support placement scheme to calculate the theoretical force value of each support point under the action of the workpiece's own weight. The force change trend of each support point after being affected by the magnetic force is analyzed in combination with the unstable area distribution data. When the predicted force change rate exceeds the preset range, the three-point support placement scheme is recalculated until the predicted force change rate is within the preset range, thereby obtaining a stable state judgment result of the workpiece.

[0011] Optionally, the pre-scanning of the surface of the workpiece to be transferred on the workstation to obtain magnetic field intensity distribution data on the workpiece surface, and obtaining two optimal clamping points of the workpiece based on the magnetic field intensity distribution data, includes:

[0012] Performing a first magnetic field intensity scan within a preset time after the workpiece is processed to obtain initial magnetic field intensity distribution data on the workpiece surface;

[0013] At a preset time interval after the first magnetic field strength scan is completed, performing a second magnetic field strength scan on the workpiece to obtain magnetic field strength distribution data under a residual heat state on the workpiece surface;

[0014] Comparative analysis is performed on the initial magnetic field intensity distribution data and the magnetic field intensity distribution data under the residual heat state, and an area where the magnetic field intensity change rate on the workpiece surface is less than a preset threshold is determined as a magnetic field intensity stable area;

[0015] In the magnetic field strength stable region, two points with a distance of 180°±5° and the smallest magnetic field strength are selected as the two optimal clamping points.

[0016] Optionally, the comparative analysis of the initial magnetic field intensity distribution data and the magnetic field intensity distribution data in the residual heat state to determine an area where the magnetic field intensity change rate on the workpiece surface is less than a preset threshold as a magnetic field intensity stable area includes:

[0017] Divide the workpiece surface into a cutting zone, a non-cutting transition zone and an unprocessed zone, wherein the cutting zone is the area in direct contact with the tool, the non-cutting transition zone is the heat-affected zone within a range of no more than 5 mm outside the cutting zone, and the unprocessed zone is the remaining surface area away from the cutting zone;

[0018] Performing orthogonal analysis on the initial magnetic field intensity distribution data of the cutting processing area and the magnetic field intensity distribution data under the residual heat state to obtain transient magnetic field change data of the cutting processing area;

[0019] Performing harmonic analysis on the initial magnetic field intensity distribution data of the non-cutting transition zone and the magnetic field intensity distribution data in the residual heat state to obtain magnetic field variation period data of the non-cutting transition zone;

[0020] Based on the transient magnetic field change data, determining the magnetic field influence radius of the cutting processing area, and screening out a first type of candidate area in the unprocessed area that exceeds the magnetic field influence radius;

[0021] Based on the magnetic field variation period data, determining the thermal stress diffusion range of the non-cutting transition zone, and screening out a second type of candidate area that exceeds the thermal stress diffusion range from the first type of candidate areas;

[0022] A difference analysis is performed on the initial magnetic field intensity distribution data of the second-category candidate area and the magnetic field intensity distribution data in the residual heat state, and an area where the difference is less than a preset threshold is determined as a magnetic field intensity stable area.

[0023] Optionally, the data processing of the magnetic field intensity distribution data, determining the mean value of the magnetic field intensity of the two optimal clamping points as a reference value, marking the area where the circumferential magnetic field intensity variation exceeds a preset multiple of the reference value, and obtaining the unstable area distribution data on the workpiece surface includes:

[0024] Taking the average magnetic field strength of the two best clamping points as a reference value, setting detection reference points every 30° around the workpiece to obtain circumferential magnetic field detection data on the workpiece surface;

[0025] Performing circumferential Fourier decomposition on the circumferential magnetic field detection data, extracting frequency components therein, and marking a region where the high-frequency component exceeds a first preset threshold as a first type of magnetization abnormality region;

[0026] Analyze the phase characteristics of the circumferential magnetic field detection data, and mark the area where the phase difference of adjacent detection points exceeds a second preset threshold as a second type of magnetization abnormality area;

[0027] Calculating the magnetic field gradient of each detection point on the workpiece surface, marking the area where the magnetic field gradient exceeds the preset multiple of the reference value as the third type of magnetization abnormality area;

[0028] Analyze the spatial distribution relationship between the first type of magnetization anomaly region, the second type of magnetization anomaly region, and the third type of magnetization anomaly region, and mark the connection area between adjacent areas as a magnetic field diffusion area;

[0029] A union of the first type of abnormal magnetization region, the second type of abnormal magnetization region, the third type of abnormal magnetization region and the magnetic field diffusion region is determined as unstable region distribution data on the workpiece surface.

[0030] Optionally, performing circumferential Fourier decomposition on the circumferential magnetic field detection data, extracting frequency components therein, and marking an area where the high-frequency component exceeds a first preset threshold as a first type of magnetization abnormality area includes:

[0031] Expanding the circumferential magnetic field detection data according to a sampling point sequence to construct a discrete sequence of magnetic field intensity;

[0032] Performing window function smoothing on the discrete sequence of magnetic field intensity to eliminate the influence of endpoint mutation on spectrum analysis;

[0033] Perform fast Fourier transform on the smoothed sequence to obtain the frequency spectrum distribution characteristics of the magnetic field intensity;

[0034] Based on the spectrum distribution characteristics, calculating the energy contribution rate of each frequency component, and defining the frequency component whose energy contribution rate exceeds a first preset threshold as an abnormal frequency component;

[0035] According to the amplitude distribution of the abnormal frequency component in the original magnetic field detection data, the area where the amplitude exceeds the first preset threshold is marked as a first type of magnetization abnormality area.

[0036] Optionally, the performing of magnetic torque analysis on the unstable region distribution data, taking the line connecting the two optimal clamping points as a reference, calculating the synthetic magnetic torque of each circumferential magnetized region of the workpiece, and obtaining the optimal placement angle of the workpiece, comprises:

[0037] Projecting the unstable region distribution data into a polar coordinate system with a line connecting the two optimal clamping points as a reference axis to obtain spatial distribution data of the magnetized region;

[0038] Discretizing the spatial distribution data of the magnetized area, dividing the workpiece into N sector-shaped areas in the circumferential direction, calculating the equivalent magnetization intensity of each sector-shaped area, and obtaining a circumferential magnetization intensity distribution sequence;

[0039] According to the circumferential magnetization intensity distribution sequence, the fan-shaped area is divided into a strong magnetization area, a medium magnetization area and a weak magnetization area according to the magnetization intensity, and the center of gravity position of each area is calculated to obtain the magnetic moment calculation base point;

[0040] Taking the reference axis as a reference, respectively calculating the magnetic moments generated by the strong magnetization region, the medium magnetization region and the weak magnetization region, and obtaining the moment distribution characteristics of each magnetization region;

[0041] Based on the torque distribution characteristics, the synthetic magnetic torque of the workpiece at different angles is calculated to obtain a magnetic torque balance curve of the workpiece;

[0042] According to the magnetic moment balance curve, the angle at which the synthetic magnetic moment is the smallest and in a stable equilibrium position is selected as the optimal placement angle.

[0043] Optionally, based on the optimal placement angle, an area on the workpiece surface having a preset angle with the line connecting the two optimal clamping points and having the smallest magnetic field strength is selected as the first contact point, and two points with the smallest magnetic field strength are selected on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece, including:

[0044] An angular coordinate system with the optimal placement angle as the starting direction is established on the workpiece surface, and the angle of the line connecting the two optimal clamping points is set to 0° to obtain angular positioning data of the workpiece surface;

[0045] Performing regional segmentation on the angle positioning data, dividing the workpiece surface into a plurality of sector-shaped search areas with an angle of 15°, calculating the average magnetic field intensity in each search area, and obtaining a magnetic field intensity distribution map of the workpiece surface;

[0046] In the magnetic field intensity distribution map, a sector-shaped search area with an angle of 90°±15° with the line connecting the two optimal clamping points is marked, and an area with the smallest magnetic field intensity is selected as a candidate area for first contact;

[0047] Finely scan the first contact candidate area, reacquire magnetic field strength data at intervals of 5°, and select the point with the smallest magnetic field strength as the first contact point;

[0048] Taking the first contact point as the center, within the range of 120°±10° on both sides thereof, select the point with the smallest magnetic field intensity as the auxiliary support candidate point;

[0049] A force balance analysis is performed on the candidate auxiliary support points, and two points with the most uniform force are selected as the auxiliary support points to obtain the three-point support placement plan.

[0050] Optionally, the three-point support placement scheme is subjected to mechanical simulation analysis, the theoretical force value of each support point under the deadweight of the workpiece is calculated, and the force change trend of each support point after being affected by the magnetic force is analyzed in combination with the unstable area distribution data. When the predicted force change rate exceeds a preset range, the three-point support placement scheme is recalculated until the predicted force change rate is within the preset range, and a stable state determination result of the workpiece is obtained, including:

[0051] According to the weight distribution parameters of the workpiece and the geometric position relationship of the three-point support, the static force components of each support point are calculated;

[0052] Based on the unstable area distribution data, analyzing the torque contribution of the magnetized area around each support point to the support point, and obtaining magnetic induced torque data;

[0053] Performing vector superposition of the static force component and the magnetic induced torque data to obtain a predicted value of the resultant force of each support point;

[0054] Calculating the deviation rate of the predicted value of the resultant force relative to the static force component and comparing it with a preset stability threshold;

[0055] When the deviation rate of any support point exceeds the stability threshold, return to the step of "based on the optimal placement angle, select an area on the workpiece surface with a preset angle with the line connecting the two optimal clamping points and with the smallest magnetic field strength as the first contact point, and select two points with the smallest magnetic field strength on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece" and recalculate the three-point support placement plan until the deviation rates of all support points are less than the stability threshold, and output the final stable state judgment result.

[0056] A second aspect of the present invention provides a workpiece positioning device for a CNC lathe based on magnetization characteristics, the workpiece positioning device for a CNC lathe based on magnetization characteristics comprising:

[0057] A magnetic field pre-scanning module is used to pre-scan the surface of the workpiece to be transferred on the workstation, obtain magnetic field intensity distribution data on the workpiece surface, and obtain two optimal clamping points of the workpiece based on the magnetic field intensity distribution data;

[0058] An unstable region identification module is used to process the magnetic field intensity distribution data, determine the average value of the magnetic field intensity of the two best clamping points as a reference value, mark the region where the circumferential magnetic field intensity variation exceeds a preset multiple of the reference value, and obtain the unstable region distribution data on the workpiece surface;

[0059] A magnetic moment analysis module is used to perform magnetic moment analysis on the unstable area distribution data, and to calculate the synthetic magnetic moment of each circumferential magnetized area of ​​the workpiece based on the line connecting the two optimal clamping points, so as to obtain the optimal placement angle of the workpiece;

[0060] A support point determination module is used to select, based on the optimal placement angle, an area on the workpiece surface where the angle between the two optimal clamping points is a preset angle and the magnetic field strength is the smallest as the first contact point, and select two points with the smallest magnetic field strength on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece;

[0061] The stability analysis module is used to perform mechanical simulation analysis on the three-point support placement scheme, calculate the theoretical force value of each support point under the action of the workpiece's own weight, and analyze the force change trend of each support point after being affected by the magnetic force in combination with the unstable area distribution data. When the predicted force change rate exceeds the preset range, the three-point support placement scheme is recalculated until the predicted force change rate is within the preset range, thereby obtaining a stable state judgment result of the workpiece.

[0062] The third aspect of the present invention provides a CNC lathe workpiece positioning system based on magnetization features, comprising: a memory and at least one processor, wherein instructions are stored in the memory, and the memory and the at least one processor are interconnected through lines; the at least one processor calls the instructions in the memory so that the CNC lathe workpiece positioning system based on magnetization features executes the steps of the above-mentioned CNC lathe workpiece positioning method based on magnetization features.

[0063] The CNC lathe workpiece positioning method based on magnetization characteristics provided in the embodiment of the present application adopts the technical idea of ​​"predicting in advance and actively avoiding" to achieve control of the magnetization phenomenon:

[0064] First, the workpiece surface is pre-scanned to obtain the magnetic field intensity distribution data, and two optimal clamping points are selected based on the data. This pre-identification method ensures that the position with the lowest magnetization degree is selected when the robot grips the workpiece, reducing the additional magnetization effect that may be caused by the robot gripping process from the source.

[0065] Secondly, the method innovatively introduces the concept of a reference value for magnetic field strength, taking the average value of the magnetic field strength at the two best clamping points as the reference, and obtaining the distribution data of unstable areas on the workpiece surface by marking the areas where the circumferential magnetic field strength changes by a preset multiple of the reference value. This determination method based on the reference value makes the identification of abnormal magnetization areas on the workpiece surface more accurate and reliable.

[0066] Thirdly, the method analyzes the magnetic moment of the unstable area distribution data, takes the line connecting the two best clamping points as the benchmark, calculates the synthetic magnetic moment of each magnetized area, and thus obtains the optimal placement angle. This analysis method based on magnetic moment balance can accurately predict the instability that may occur when the workpiece is placed at different angles.

[0067] Finally, when determining the three-point support placement scheme, the method fully utilized the magnetic field distribution characteristics obtained in the early stage, selected the appropriate first contact point and auxiliary support point, and performed mechanical simulation analysis to achieve precise control of the workpiece stability. This method of predicting stability before actual placement avoids the passive situation of discovering problems after the workpiece is placed in the traditional method.

[0068] Through the synergistic effect of the above-mentioned technical features, the method of the present invention realizes the whole process monitoring and active prediction of the magnetization state of the workpiece, fundamentally solves the displacement problem of the workpiece on the measuring platform caused by magnetization, ensures the stability of the workpiece during the measurement process, and provides a reliable prerequisite for high-precision measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0070] Figure 1 A schematic diagram of an embodiment of a method for positioning a workpiece of a CNC lathe based on magnetization characteristics in an embodiment of the present invention;

[0071] Figure 2 A schematic diagram of an embodiment of a workpiece positioning device for a CNC lathe based on magnetization characteristics in an embodiment of the present invention;

[0072] Figure 3 A schematic diagram of an embodiment of a workpiece positioning system for a CNC lathe based on magnetization characteristics in an embodiment of the present invention;

[0073] Figure 4 It is a schematic diagram of an embodiment of a CNC machine tool of a CNC lathe workpiece positioning system based on magnetization characteristics in an embodiment of the present invention.

[0074] Description of Figure Numbers:

[0075] 100. CNC lathe; 1. Lathe mechanism; 2. Loading bin; 3. Electric box; 4. Loading head; 5. Loading window; 6. Unloading window; 7. Unloading head; 8. Unloading bin.

[0076] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0077] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0078] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0079] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, "and / or" in the full text includes three solutions. Taking A and / or B as an example, it includes technical solution A, technical solution B, and technical solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, which must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0080] An embodiment of the present application provides a method for positioning a workpiece of a CNC lathe based on magnetization characteristics. Figure 1 A flow chart of a method for positioning a workpiece of a CNC lathe based on magnetization characteristics provided in one embodiment of the present application. In this embodiment, the method includes:

[0081] See also Figure 1 , pre-scanning the surface of the workpiece to be transferred on the workstation, obtaining magnetic field intensity distribution data on the workpiece surface, and obtaining two optimal clamping points of the workpiece based on the magnetic field intensity distribution data;

[0082] In one embodiment of the present invention, the surface of the workpiece to be transferred on the workstation is pre-scanned to obtain magnetic field intensity distribution data on the workpiece surface, and two optimal clamping points of the workpiece are obtained based on the magnetic field intensity distribution data, including: performing a first magnetic field intensity scan within a preset time after the workpiece is processed to obtain initial magnetic field intensity distribution data on the workpiece surface; performing a second magnetic field intensity scan on the workpiece at a preset time interval after the first magnetic field intensity scan is completed to obtain magnetic field intensity distribution data on the workpiece surface under a residual heat state; comparing and analyzing the initial magnetic field intensity distribution data and the magnetic field intensity distribution data under the residual heat state, determining an area where the rate of change of magnetic field intensity on the workpiece surface is less than a preset threshold as a stable magnetic field intensity area; in the stable magnetic field intensity area, selecting two points with a distance of 180°±5° and the smallest magnetic field intensity as the two optimal clamping points.

[0083] Specifically, during the machining of precision parts, the magnetization state of the workpiece surface will change. This change mainly comes from two aspects: first, during the machining process, the mechanical stress generated by metal cutting will cause changes in the internal crystal structure of the material. Since the magnetism of metal materials is closely related to their crystal structure (for example, during the cutting process, the high-speed relative movement between the tool and the workpiece surface will cause lattice distortion in the local area, which will change the magnetization characteristics of the material), the machining process will change the magnetization state of the workpiece surface; second, the influence of temperature changes. The magnetization characteristics of metal materials are related to temperature (for example, when the temperature rises, the arrangement of magnetic domains inside the material will become more disordered, causing the magnetization degree of the material to change).

[0084] In order to accurately obtain the magnetic field intensity distribution on the workpiece surface, a circular array of magnetic field sensors is used for scanning. Specifically, multiple Hall sensors are evenly arranged around the workpiece (for example, 24 Hall sensors are used, one installed every 15 degrees), and the sensitive surface of each sensor faces the workpiece surface and maintains the same distance from the workpiece surface (for example, 5 mm). These sensors work simultaneously and can obtain magnetic field intensity data at different positions on the workpiece surface at the same time. Hall sensors are selected because they have high sensitivity (can detect magnetic field changes of the order of 0.1 millitesla) and good linear response characteristics.

[0085] The first scan is performed immediately after the workpiece is machined. At this time, the temperature distribution on the workpiece surface is uneven. Take a typical turning process as an example: the temperature of the area just machined may be as high as 200-300°C (this is because most of the mechanical energy is converted into heat energy during metal cutting), while the surface far away from the machining area may only be 30-40°C. This temperature difference will cause the magnetization state of the workpiece surface to be unstable.

[0086] Wait for 2-3 minutes before scanning for the second time. During this time, the surface temperature of the workpiece will drop to about 80-100℃, at which time the temperature distribution will be more uniform and the magnetization characteristics of the material will tend to be stable. If the waiting time is too short, the temperature gradient will still be large, which will affect the accuracy of the magnetic field measurement; if the waiting time is too long, it will reduce production efficiency.

[0087] When performing comparative analysis, the magnetic field strength data measured twice at the same position are calculated. For example, assuming that the sensor at the 0-degree position measures a magnetic field strength of 0.5 millitesla in the first scan and 0.48 millitesla in the second scan, the rate of change of the magnetic field strength at this point is |(0.48-0.5) / 0.5|×100%=4%. The threshold of 5% is set based on the statistical results of a large amount of experimental data. Generally speaking, the magnetization state of the area with a change rate of less than 5% is relatively stable and will not have a significant impact on the subsequent workpiece positioning.

[0088] When selecting the clamping point, the requirement that the two points are 180°±5° apart is based on the actual working characteristics of the manipulator gripper. The two clamping surfaces of the standard manipulator gripper are completely parallel when clamping, and theoretically should be exactly 180 degrees apart. However, considering the installation error of the mechanical system and the deformation during operation, an error of ±5 degrees is allowed. This error range not only ensures the reliability of clamping, but also provides a certain degree of flexibility for selecting the best clamping point. For example, if an ideal point with a magnetic field strength of 0.2 millitesla is found at the 0-degree position, then another point with the smallest magnetic field strength can be found within the range of 175-185 degrees, rather than being strictly limited to the 180-degree position.

[0089] In one embodiment of the present invention, the initial magnetic field intensity distribution data and the magnetic field intensity distribution data under the residual heat state are compared and analyzed to determine the area where the magnetic field intensity change rate of the workpiece surface is less than a preset threshold as a magnetic field intensity stable area, including: dividing the workpiece surface into a cutting processing area, a non-cutting transition area and an unprocessed area, the cutting processing area is an area in direct contact with the tool, the non-cutting transition area is a heat-affected area within a range of no more than 5 mm outside the cutting processing area, and the unprocessed area is the remaining surface area away from the cutting area; orthogonal analysis is performed on the initial magnetic field intensity distribution data of the cutting processing area and the magnetic field intensity distribution data under the residual heat state to obtain transient magnetic field change data of the cutting processing area; and the non-cutting transition area is a heat-affected area within a range of no more than 5 mm outside the cutting processing area. The initial magnetic field intensity distribution data of the transition zone and the magnetic field intensity distribution data under the residual heat state are subjected to harmonic analysis to obtain the magnetic field change periodic data of the non-cutting transition zone; based on the transient magnetic field change data, the magnetic field influence radius of the cutting processing zone is determined, and the first type of candidate area in the unprocessed area that exceeds the magnetic field influence radius is screened out; based on the magnetic field change periodic data, the thermal stress diffusion range of the non-cutting transition zone is determined, and the second type of candidate area that exceeds the thermal stress diffusion range is screened out in the first type of candidate area; the initial magnetic field intensity distribution data of the second type of candidate area and the magnetic field intensity distribution data under the residual heat state are subjected to difference analysis, and the area where the difference is less than a preset threshold is determined as the magnetic field intensity stable area.

[0090] Specifically, during the workpiece processing, different areas are affected by the processing to different degrees, so it is necessary to divide the workpiece surface into reasonable areas. The first is the cutting area, which is the area where the tool directly acts. In typical turning, this area is manifested as a band area (for example, when turning the outer cylindrical surface of the valve core, the cutting area is the annular band area around the tool entry point, with a width of about the width of the tool cutting edge, usually 2-3 mm). In this area, the material undergoes severe plastic deformation and temperature changes, and the magnetization state changes most significantly.

[0091] The non-cutting transition zone refers to the area within 5 mm outside the cutting area. In the metal cutting process, about 80% of the cutting work is converted into heat energy, part of which is carried away with the chips and part is transferred to the workpiece. Through infrared thermal imager observation, it can be found that the diffusion range of heat in the workpiece material is mainly concentrated within 5 mm outside the cutting area. In this area, although no actual cutting action occurs, the material undergoes obvious temperature cycles, and this temperature change will affect the magnetic properties of the material.

[0092] The unprocessed area refers to the remaining surface area away from the cutting area. These areas basically remain in their original state and are relatively less affected by the machining process.

[0093] The purpose of orthogonal analysis of the magnetic field intensity data in the cutting process area is to separate the influence of different factors on the magnetization state. In specific operations, the magnetic field intensity data is decomposed according to the two orthogonal directions of cutting direction and radial direction. For example, when turning the outer cylindrical surface of the valve core, the tangential (consistent with the cutting speed direction) and radial (perpendicular to the workpiece surface) magnetic field intensity components can be obtained respectively. This decomposition can help identify the magnetization effect caused by cutting (mainly manifested in the tangential direction) and the magnetization effect caused by extrusion deformation (mainly manifested in the radial direction).

[0094] The harmonic analysis of the non-cutting transition zone is based on the consideration that the temperature and stress changes in this area have periodic characteristics. Taking turning as an example, when the tool is cutting, the heat will diffuse to the surroundings periodically, causing the temperature of the transition zone to fluctuate. By performing Fourier transform on the magnetic field intensity data, the spectral characteristics of the magnetic field change can be obtained. Usually, the magnetization changes directly related to the machining process will appear as fundamental frequencies and harmonic components related to the spindle speed.

[0095] Based on the transient magnetic field change data of the cutting area (i.e. the change of magnetic field intensity in each direction obtained by orthogonal analysis), the attenuation law of the magnetic field effect can be calculated. The magnetic field intensity usually decays exponentially, and the influence radius can be defined as the distance when the magnetic field intensity decays to 10% of the initial value. This distance is usually 3-4 times the width of the cutting area. In the unprocessed area, the area beyond this influence radius is marked as the first type of candidate area.

[0096] The determination of the thermal stress diffusion range is based on the magnetic field change periodic data of the non-cutting transition zone. By analyzing the harmonic characteristics of the magnetic field change, the area affected by thermal stress can be identified. Generally speaking, when the harmonic amplitude is reduced to less than 5% of the fundamental amplitude, it can be considered that the location has exceeded the significant influence range of thermal stress. In the first category of candidate areas, the areas beyond this thermal stress diffusion range are further screened to form the second category of candidate areas.

[0097] Finally, performing a difference analysis on the second type of candidate areas is a conservative verification step. The magnetic field strength data of the two scans of the area are directly subtracted. If the difference is less than the preset threshold (for example, 0.1 millitesla), it can be confirmed that the magnetization state of the area is indeed stable and suitable as the selection area of ​​the clamping point. This multiple screening method can maximize the stability of the magnetization state of the selected area, thereby providing a reliable guarantee for subsequent precise positioning.

[0098] Please continue reading Figure 1, performing data processing on the magnetic field intensity distribution data, determining the mean value of the magnetic field intensity of the two optimal clamping points as a reference value, marking the area where the circumferential magnetic field intensity variation exceeds a preset multiple of the reference value, and obtaining the unstable area distribution data on the workpiece surface;

[0099] In one embodiment of the present invention, the data processing of the magnetic field intensity distribution data, determining the mean value of the magnetic field intensity of the two best clamping points as a reference value, marking the area where the circumferential magnetic field intensity variation exceeds a preset multiple of the reference value, and obtaining the unstable area distribution data on the workpiece surface includes: taking the mean value of the magnetic field intensity of the two best clamping points as a reference value, setting detection reference points every 30° in the circumferential direction of the workpiece to obtain the circumferential magnetic field detection data on the workpiece surface; performing circumferential Fourier decomposition on the circumferential magnetic field detection data, extracting the frequency components therein, and marking the area where the high-frequency component exceeds a first preset threshold as a first type of magnetization abnormality area; analyzing the circumferential magnetic field Phase characteristics of field detection data, marking areas where the phase difference of adjacent detection points exceeds a second preset threshold as second-type magnetization anomaly areas; calculating the magnetic field gradient of each detection point on the workpiece surface, marking areas where the magnetic field gradient exceeds a preset multiple of the reference value as third-type magnetization anomaly areas; analyzing the spatial distribution relationship of the first-type magnetization anomaly area, the second-type magnetization anomaly area and the third-type magnetization anomaly area, marking the connecting area between adjacent areas as a magnetic field diffusion area; and determining the union of the first-type magnetization anomaly area, the second-type magnetization anomaly area, the third-type magnetization anomaly area and the magnetic field diffusion area as the unstable area distribution data on the workpiece surface.

[0100] Specifically, in order to comprehensively evaluate the magnetization state distribution characteristics of the workpiece surface, a complete magnetic field abnormality area identification system needs to be established. First, the mean value of the magnetic field intensity at the two best clamping points is used as the reference value. Since these two points have been confirmed as locations with stable magnetic field intensity and small values, their mean value can be used as a reference standard for judging the degree of magnetization abnormality in other areas. For example, if the magnetic field intensity at the two clamping points is 0.15 millitesla and 0.25 millitesla respectively, the reference value is 0.2 millitesla.

[0101] A detection reference point is set every 30 degrees around the workpiece, so that a total of 12 detection points are set on the entire circumference. Too small an interval will lead to data redundancy and increase the amount of calculation, while too large an interval may miss important magnetic field change features. At each detection point, a high-precision magnetic field sensor (such as a Hall sensor with a sensitivity of 0.01 millitesla) is used to collect magnetic field strength data.

[0102] Performing circumferential Fourier decomposition on these circumferential magnetic field detection data essentially converts the spatial distribution of magnetic field intensity into an expression in the frequency domain. The advantage of this analysis method is that it can clearly identify the periodic characteristics of the magnetic field distribution. For example, assuming that on a workpiece, the magnetic field intensity data of 12 detection points are [0.2, 0.3, 0.8, 0.9, 0.7, 0.4, 0.2, 0.3, 0.8, 0.9, 0.7, 0.4] millitesla, through Fourier decomposition, it can be found that these data have obvious third harmonic characteristics, indicating that there are periodic magnetization anomalies on the surface of the workpiece. If the amplitude of the high-frequency component (usually the component more than 3 times the fundamental frequency) of a certain area exceeds 30% of the fundamental amplitude (that is, the first preset threshold), the area is marked as the first type of magnetization anomaly area.

[0103] Phase feature analysis focuses on the spatial continuity of changes in magnetic field intensity. In the above example, if the magnetic field intensities of two adjacent detection points (for example, 0 and 30 degrees) are 0.2 millitesla and 0.8 millitesla respectively, this mutation indicates that there may be significant magnetization anomalies in the area. Specifically, the phase angle of the magnetic field intensity data of adjacent detection points is calculated (obtained by the inverse tangent function). If the phase difference exceeds 45 degrees (i.e., the second preset threshold), it is marked as the second type of magnetization anomaly area.

[0104] The magnetic field gradient is calculated by dividing the difference in magnetic field strength between adjacent test points by the arc length distance between them. For example, if the magnetic field strengths of two adjacent test points (with a spacing of 30 degrees, i.e., π / 6 times the radius of the workpiece) are 0.2 millitesla and 0.8 millitesla respectively, the magnetic field gradient of the area is (0.8-0.2) / (πR / 6) millitesla / mm, where R is the radius of the workpiece. If this gradient value exceeds 3 times the baseline value (i.e., the preset multiple), it is marked as a third-category magnetization abnormal area.

[0105] These three types of magnetization anomaly areas may overlap or be adjacent in space. For example, a high-frequency anomaly area (the first type) may be next to a gradient anomaly area (the third type). To be conservative, the transition area between these adjacent areas needs to be marked as a potential unstable area (i.e., magnetic field diffusion area). In specific operations, if the angular interval between two identified anomaly areas is less than 60 degrees, the area between them is also marked as a magnetic field diffusion area.

[0106] Finally, the union of all identified abnormal areas and diffusion areas is used as the unstable area distribution data of the workpiece surface. This multi-dimensional analysis method (frequency domain features, phase features, and spatial gradients) combined with a conservative diffusion area definition strategy can comprehensively and reliably identify all areas on the workpiece surface that may have magnetization problems, providing an important reference for subsequent workpiece positioning.

[0107] In one embodiment of the present invention, the circumferential magnetic field detection data is subjected to circumferential Fourier decomposition to extract frequency components therefrom, and an area where the high-frequency components exceed a first preset threshold value is marked as a first type of magnetization abnormality area, including: expanding the circumferential magnetic field detection data according to a sampling point sequence to construct a discrete sequence of magnetic field intensity; performing window function smoothing on the discrete sequence of magnetic field intensity to eliminate the influence of endpoint mutations on spectral analysis; performing fast Fourier transform on the smoothed sequence to obtain spectral distribution characteristics of the magnetic field intensity; based on the spectral distribution characteristics, calculating the energy contribution rate of each frequency component, and defining the frequency component whose energy contribution rate exceeds the first preset threshold value as an abnormal frequency component; and according to the amplitude distribution of the abnormal frequency component in the original magnetic field detection data, marking the area where the amplitude exceeds the first preset threshold value as a first type of magnetization abnormality area.

[0108] Specifically, in the analysis of magnetic field anomalies on the surface of the workpiece, it is necessary to perform a fine frequency domain analysis on the circumferential magnetic field detection data. First, the magnetic field detection data is arranged into a discrete sequence according to the spatial order of the sampling points. For example, a data point is collected every 30 degrees on the circumference of the workpiece, and a total of 12 magnetic field intensity values ​​[0.25, 0.28, 0.45, 0.89, 0.92, 0.85, 0.76, 0.45, 0.28, 0.25, 0.27, 0.26] millitesla are obtained. These data constitute a discrete sequence of magnetic field intensity according to the spatial position order of the sampling points.

[0109] Since this sequence is connected at the beginning and the end (the artifact is in a circular shape), directly performing Fourier transform may produce a mutation at the beginning and the end of the sequence, affecting the accuracy of the spectrum analysis. In order to solve this problem, the sequence needs to be smoothed by a window function. Specifically, the data is weighted using the Hanning window function, and the expression of the Hanning window function is w(n)=0.5(1-cos(2πn / N)), where n is the sequence number of the data point and N is the total length of the sequence. For example, for the first data point in the above sequence, 0.25 millitesla, it becomes 0.25×w(1) millitesla after being weighted by the Hanning window. This processing method can make the transition between the beginning and the end of the sequence smoother and avoid the high-frequency components introduced artificially.

[0110] By performing fast Fourier transform (FFT) on the smoothed sequence, the spectral distribution characteristics of the magnetic field intensity can be obtained. In actual operation, using the number of data points based on the power of 2 (such as expanding 12 points by zero padding to 16 points) for FFT calculation can improve the calculation efficiency. The result obtained after the transformation contains the amplitude and phase information of different frequency components. For example, the following spectrum may be obtained: the amplitude of the zero-frequency component (DC component) is 0.5 millitesla, the amplitude of the fundamental frequency component is 0.3 millitesla, the amplitude of the second harmonic component is 0.15 millitesla, the amplitude of the third harmonic component is 0.08 millitesla, etc.

[0111] For each frequency component, calculate its energy contribution rate. The energy contribution rate is calculated by dividing the square of the amplitude of the frequency component by the sum of the squares of the amplitudes of all frequency components. For example, if the amplitude of a frequency component is 0.3 millitesla, and the sum of the squares of the amplitudes of all components is 1.0 millitesla squared, the energy contribution rate of the component is 9%. Set the first preset threshold to 10% (the selection of this threshold is based on a large amount of experimental data statistics). When the energy contribution rate of a frequency component exceeds 10%, it is defined as an abnormal frequency component.

[0112] Finally, the results of the frequency domain analysis need to be mapped back to the spatial domain to find the spatial positions corresponding to these abnormal frequency components. The specific approach is: the original magnetic field detection data is bandpass filtered, and the passband of the filter corresponds exactly to the frequency components marked as abnormal. For example, if the third harmonic is found to be an abnormal frequency component, the original data is processed using a bandpass filter with a center frequency three times the fundamental frequency. In the filtered data, those areas whose amplitude exceeds the first preset threshold (for example, twice the baseline value) are marked as the first type of magnetization abnormality area.

[0113] This abnormal area identification method based on spectrum analysis has important advantages: first, it can effectively distinguish periodic magnetization anomalies from random noise, thereby improving the reliability of identification; second, through window function preprocessing and reasonable threshold setting, the analysis results will not be significantly affected by the data sampling method; finally, due to the reversibility of Fourier transform, the frequency domain features can be accurately matched with the spatial position, which is convenient for subsequent workpiece positioning control.

[0114] Please continue reading Figure 1 , performing magnetic moment analysis on the unstable area distribution data, taking the line connecting the two optimal clamping points as a reference, calculating the synthetic magnetic moment of each circumferential magnetized area of ​​the workpiece, and obtaining the optimal placement angle of the workpiece;

[0115] In one embodiment of the present invention, the magnetic moment analysis is performed on the unstable region distribution data, and the synthetic magnetic moment of each magnetized region in the circumferential direction of the workpiece is calculated based on the line connecting the two optimal clamping points to obtain the optimal placement angle of the workpiece, including: projecting the unstable region distribution data into a polar coordinate system with the line connecting the two optimal clamping points as the reference axis to obtain the spatial distribution data of the magnetized region; discretizing the spatial distribution data of the magnetized region to divide the workpiece into N sector regions in the circumferential direction, calculating the equivalent magnetization intensity of each sector region, and obtaining the circumferential magnetization intensity distribution sequence; according to The circumferential magnetization intensity distribution sequence divides the fan-shaped area into a strong magnetization area, a medium magnetization area and a weak magnetization area according to the magnetization intensity, calculates the center of gravity position of each area, and obtains the magnetic moment calculation base point; with the reference axis as a reference, calculates the magnetic moment generated by the strong magnetization area, the medium magnetization area and the weak magnetization area respectively, and obtains the moment distribution characteristics of each magnetization area; based on the moment distribution characteristics, calculates the synthetic magnetic moment of the workpiece at different angles, and obtains the magnetic moment balance curve of the workpiece; according to the magnetic moment balance curve, selects the angle with the smallest synthetic magnetic moment and in a stable equilibrium position as the optimal placement angle.

[0116] Specifically, when determining the optimal placement angle of the workpiece, it is first necessary to establish a suitable coordinate system to analyze the distribution of the magnetized area. The line connecting the two optimal clamping points is used as the reference axis (defined as the 0 degree direction) to establish a polar coordinate system. For example, if there is an abnormal magnetization area on the workpiece located 20 mm from the center of the workpiece and 45 degrees deflected from the reference axis, it can be represented as (20, 45°) in the polar coordinate system. This representation method facilitates the subsequent analysis of the torque effect of the magnetized area relative to the center of the workpiece.

[0117] In order to facilitate calculation, the continuous magnetization area needs to be discretized. The specific method is to divide the workpiece into several sector areas evenly in the circumferential direction (for example, 360 degrees are divided into 24 sector areas, each sector area spans 15 degrees). For each sector area, calculate its equivalent magnetization intensity. The calculation method of the equivalent magnetization intensity is: weighted average of the magnetic field intensity values ​​of all sampling points in the sector area, and the weight coefficient is inversely proportional to the distance from the sampling point to the center of the sector. For example, there are three sampling points in a sector area, which are 5, 10, and 15 mm away from the center of the sector, respectively, and the corresponding magnetic field intensities are 0.8, 0.6, and 0.4 millitesla, respectively. The equivalent magnetization intensity of the area is (0.8×1 / 5+0.6×1 / 10+0.4×1 / 15) / (1 / 5+1 / 10+1 / 15)=0.7 millitesla.

[0118] Based on the calculated circumferential magnetization intensity distribution sequence, the sector areas are classified. Assuming that the reference value of magnetic field intensity is 0.2 millitesla, the classification can be carried out according to the following standards: the area with magnetization intensity greater than 3 times the reference value (i.e. 0.6 millitesla) is defined as a strong magnetization area, the area with magnetization intensity between 1.5 and 3 times the reference value (i.e. 0.3 to 0.6 millitesla) is defined as a medium magnetization area, and the area with magnetization intensity less than 1.5 times the reference value is defined as a weak magnetization area. The center of gravity position is calculated for each type of area. The specific method is: the center point coordinates of all sector units in this type of area are weighted averaged according to the magnetization intensity. For example, if the strong magnetization area contains two adjacent sector units, their center point polar coordinates are (20, 30°) and (20, 45°), and the magnetization intensities are 0.8 and 0.7 millitesla, respectively, then the center of gravity position is (20, 38.4°).

[0119] When calculating the magnetic torque, consider the effects of three types of magnetized regions on the workpiece. The magnetic torque generated by each magnetized region is equal to the product of the equivalent magnetization intensity of the region and the distance from its center of gravity to the center of the workpiece, multiplied by the sine value between the center of gravity and the reference axis. For example, for a strongly magnetized region located at (20, 38.4°), its magnetization intensity is 0.75 millitesla, and the magnetic torque it generates is 0.75×20×sin(38.4°)=9.3 millitesla·mm.

[0120] By rotating the workpiece (i.e. changing the direction of the reference axis), the synthetic magnetic torque generated by the three types of magnetized regions at different angles can be obtained. For example, when the workpiece is rotated 30 degrees, the sine value of each magnetized region relative to the new reference axis position needs to be recalculated, and then summed to obtain the synthetic magnetic torque. Rotate the workpiece 360 ​​degrees, calculate the synthetic magnetic torque every 5 degrees, and you will get the magnetic torque balance curve.

[0121] In the magnetic torque balance curve, find the position where the synthetic magnetic torque is the smallest. However, it is not enough to have a small magnetic torque. It is also necessary to ensure that this position is stable. The criterion for determining a stable equilibrium position is that the trend of the change in the magnetic torque within 15 degrees to the left and right of the position can generate a restoring force that returns the workpiece to that position. For example, if the synthetic magnetic torque is found to be the smallest at the 120-degree position, and within the range of 105-135 degrees, the magnetic torque generated by any position that deviates from 120 degrees tends to return the workpiece to the 120-degree position, then 120 degrees can be determined as the optimal placement angle.

[0122] This analysis method based on magnetic torque balance takes into account the spatial distribution characteristics of magnetization intensity and ensures that the workpiece will not rotate due to the action of magnetic force after placement by finding a stable equilibrium position, thereby ensuring the accuracy of positioning.

[0123] Please continue reading Figure 1, based on the optimal placement angle, an area on the workpiece surface where the angle between the line connecting the two optimal clamping points is a preset angle and the magnetic field strength is the smallest is selected as the first contact point, and two points with the smallest magnetic field strength are selected on both sides of the first contact point as auxiliary support points, to obtain a three-point support placement plan for the workpiece;

[0124] In one embodiment of the present invention, based on the optimal placement angle, an area on the workpiece surface with a preset angle to the line connecting the two optimal clamping points and with the smallest magnetic field strength is selected as the first contact point, and two points with the smallest magnetic field strength are selected on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece, including: establishing an angular coordinate system with the optimal placement angle as the starting direction on the workpiece surface, setting the angle of the line connecting the two optimal clamping points to 0°, and obtaining angular positioning data on the workpiece surface; performing regional segmentation on the angular positioning data, dividing the workpiece surface into multiple sector-shaped search areas with an angle of 15°, calculating the average magnetic field strength in each search area, and obtaining A magnetic field intensity distribution map of the workpiece surface; in the magnetic field intensity distribution map, mark a fan-shaped search area with an angle of 90°±15° with the line connecting the two optimal clamping points, and select the area with the smallest magnetic field intensity as the candidate area for first contact; perform a fine scan on the candidate area for first contact, reacquire the magnetic field intensity data at intervals of 5°, and select the point with the smallest magnetic field intensity as the first contact point; with the first contact point as the center, within the range of 120°±10° on both sides thereof, select the point with the smallest magnetic field intensity as the candidate point for auxiliary support; perform a force balance analysis on the candidate points for auxiliary support, select the two points with the most uniform force as the auxiliary support points, and obtain the three-point support placement plan.

[0125] Specifically, when determining the three-point support placement plan for the workpiece, you first need to establish an angular coordinate system that is easy to position. Use the optimal placement angle as the starting direction, and set the direction of the line connecting the two optimal clamping points to 0 degrees. For example, if the optimal placement angle is 120 degrees, and the line connecting the two clamping points is originally located at 150 degrees, then in the newly established angular coordinate system, the entire system needs to be rotated 30 degrees counterclockwise so that the line connecting the clamping points coincides with the 0-degree direction. The purpose of this is to unify the reference datum to facilitate subsequent angle measurement and calculation.

[0126] In order to systematically search for suitable support points, it is necessary to segment the workpiece surface. The specific method is to evenly divide 360 ​​degrees into 24 sector-shaped areas, and the angle of each sector-shaped area is 15 degrees. The choice of this segmentation granularity has been verified in practice: if the segmentation is too coarse (such as 30 degrees), some suitable support point positions may be missed; if the segmentation is too fine (such as 5 degrees), the calculation amount of the initial search will be greatly increased. In each sector-shaped area, multiple magnetic field sensors are arranged (for example, 5 sensors are evenly arranged in each sector-shaped area) to collect magnetic field strength data. The arithmetic mean of the magnetic field strength values ​​measured by all sensors in each area is taken as the characteristic value of the area. For example, the magnetic field strengths measured by 5 sensors in a sector-shaped area are 0.22, 0.24, 0.23, 0.21, and 0.25 millitesla, respectively, and the average magnetic field strength of the area is 0.23 millitesla.

[0127] When determining the first contact point, focus on the area near the position perpendicular to the line connecting the clamping points. Specifically, mark the fan-shaped areas with an angle of 90±15 degrees to the 0-degree direction (the direction of the clamping point line). These areas span a total of 30 degrees and usually contain two complete fan-shaped areas. Focusing on these areas is based on the principle of mechanics: when the support point is located at a perpendicular position to the line of action of the clamping force, the best support stability can be obtained. Among these candidate areas, select the area with the smallest average magnetic field strength as the first contact candidate area. For example, if in the two fan-shaped areas of 75-90 degrees and 90-105 degrees, the average magnetic field strength of the former is 0.23 millitesla and the latter is 0.19 millitesla, then the 90-105 degree area is selected as the first contact candidate area.

[0128] The selected candidate area is scanned in detail, and the 15-degree sector area is subdivided into a fine grid with one data point every 5 degrees. This fine scan uses a high-precision magnetic field sensor to collect data at every 5-degree interval. For example, in the 90-105 degree sector area, precise measurements are taken at four positions: 90 degrees, 95 degrees, 100 degrees, and 105 degrees. Assuming that the measured magnetic field strengths are 0.21, 0.18, 0.20, and 0.22 milliteslas, respectively, the 95-degree position with a magnetic field strength of 0.18 milliteslas is selected as the first contact point.

[0129] After determining the first contact point, it is necessary to find auxiliary support points on both sides of it. The search is selected within the range of 120±10 degrees on both sides of the first contact point. This range is selected based on the stability principle of three-point support: when the three support points form an equilateral triangle (that is, the angle between adjacent points is 120 degrees), the best support stability can be obtained. Within this range, a fine scanning method with an interval of 5 degrees is also used to find the point with the smallest magnetic field strength as a candidate for auxiliary support.

[0130] Finally, the candidate auxiliary support points are subjected to force balance analysis. Assuming that the weight of the workpiece is 10 Newtons and the first contact point is located at 95 degrees, multiple points with smaller magnetic field strength are found within the search range on both sides. By calculating the force distribution of the three-point support, the two points that can make the three support points most evenly stressed are selected as the final auxiliary support points. The criterion for uniform force is that the difference in the reaction force of the three support points does not exceed 20%. For example, if the force distribution of a three-point combination is 3.2 Newtons, 3.5 Newtons, and 3.3 Newtons, it is considered to be a support scheme with uniform force.

[0131] This systematic three-point support point selection method not only takes into account the influence of magnetic field strength, but also takes into account the mechanical stability of the support structure, which can ensure that the workpiece is stably and reliably supported on the measuring platform.

[0132] Please continue reading Figure 1 , perform mechanical simulation analysis on the three-point support placement scheme, calculate the theoretical force value of each support point under the action of the workpiece's own weight, and analyze the force change trend of each support point after being affected by the magnetic force in combination with the unstable area distribution data. When the predicted force change rate exceeds the preset range, recalculate the three-point support placement scheme until the predicted force change rate is within the preset range, and obtain the stable state judgment result of the workpiece.

[0133] In one embodiment of the present invention, the three-point support placement scheme is subjected to mechanical simulation analysis, the theoretical force value of each support point under the action of the workpiece's own weight is calculated, and the force change trend of each support point after being affected by the magnetic force is analyzed in combination with the unstable area distribution data. When the predicted force change rate exceeds a preset range, the three-point support placement scheme is recalculated until the predicted force change rate is within the preset range, and a stable state judgment result of the workpiece is obtained, including: calculating the static force component of each support point according to the weight distribution parameters of the workpiece and the geometric position relationship of the three-point support; analyzing the torque contribution of the magnetized area around each support point to the support point based on the unstable area distribution data to obtain magnetic induced torque data; comparing the static force component with the The magnetic induced torque data are vector-superimposed to obtain a predicted value of the resultant force of each support point; the deviation rate of the predicted value of the resultant force relative to the static force component is calculated and compared with a preset stability threshold; when the deviation rate of any support point exceeds the stability threshold, return to the step of "based on the optimal placement angle, select an area on the workpiece surface with a preset angle to the line connecting the two optimal clamping points and with the smallest magnetic field intensity as the first contact point, and select two points with the smallest magnetic field intensity on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece" to recalculate the three-point support placement plan until the deviation rates of all support points are less than the stability threshold, and output the final stable state judgment result.

[0134] Specifically, in the final stage of ensuring stable support of the workpiece, a mechanical simulation analysis of the three-point support scheme is required. First, the static force components of each support point are calculated. This calculation is based on the weight distribution of the workpiece and the geometric position relationship of the support points. For example, for a cylindrical workpiece with a weight of 10 Newtons and a center of gravity at the geometric center, if the three support points are distributed in an equilateral triangle on the horizontal plane (the angle between adjacent points is 120 degrees), according to the principles of statics, each support point should theoretically bear 1 / 3 of the weight of the workpiece, that is, a static load of about 3.33 Newtons. If the center of gravity of the workpiece deviates from the geometric center (for example, it deviates by 5 mm), or the three support points are not evenly spaced (for example, the angles are 110 degrees, 125 degrees, and 125 degrees), it is necessary to recalculate the static force of each support point through the moment balance equation.

[0135] Next, we analyze the influence of the magnetization effect on the supporting force. For each supporting point, it is necessary to examine the additional torque generated by the surrounding magnetized area. The specific analysis method is: with the supporting point as the center, within a radius of 10 mm, the magnetic field strength data of the unstable area is converted into an equivalent magnetic force. For example, if there is an area with a magnetic field strength of 0.8 millitesla 5 mm around supporting point A and an area of ​​20 square millimeters, the additional torque generated by this area on the supporting point can be calculated based on the magnetic field gradient and magnetic permeability. It is assumed that the calculated torque value is 0.2 Newton mm. Perform similar calculations on all magnetized areas around the supporting point, and superimpose the resulting vectors to obtain the total magnetic induced torque on the supporting point.

[0136] The static force component is vector-superimposed with the force induced by magnetic force to obtain the actual expected force of each support point. For example, if the static force of support point A is 3.33 Newtons (vertically upward), and the magnetic force induces a horizontal force of 0.5 Newtons and a vertical downward force of 0.3 Newtons, then the predicted value of the combined force at this point is: 3.03 Newtons in the vertical direction (3.33-0.3), 0.5 Newtons in the horizontal direction, and the combined force is √(3.03²+0.5²)=3.07 Newtons (where √ is the square root, the same applies below), and the direction deviates from the vertical direction by 9.4 degrees.

[0137] For each support point, calculate the deviation rate between its predicted value of the combined force and the ideal static force. The calculation of the deviation rate includes two aspects: force magnitude deviation and direction deviation. For example, the force magnitude deviation rate of the support point A mentioned above is |(3.07-3.33)| / 3.33=7.8%, and the direction deviation is 9.4 degrees. Set the stability threshold as follows: the force magnitude deviation rate does not exceed 10%, and the direction deviation does not exceed 15 degrees. If any deviation indicator of any support point exceeds the threshold, the support plan needs to be readjusted.

[0138] The strategy for adjusting the support scheme is to first identify the support point with the largest deviation, and then look for alternative points with lower magnetization in the vicinity (for example, within ±15 degrees). A complete mechanical analysis should be repeated after each adjustment. For example, if the deviation of support point A is found to be too large, it may be necessary to adjust its position from the original 95 degrees to 90 degrees or 100 degrees, and adjust the positions of the other two support points accordingly to maintain the stability of the overall support structure.

[0139] This iterative optimization process continues until the mechanical states of all support points meet the stability requirements. The final output of the stability state determination results includes: the precise position coordinates of the three support points, the expected force magnitude and direction of each point, and the stability evaluation index of the overall support structure. This verification method based on mechanical simulation ensures that the workpiece can obtain stable and reliable support when it is actually placed.

[0140] The above describes the CNC lathe workpiece positioning method based on the magnetization characteristics in the embodiment of the present invention. The following describes the CNC lathe workpiece positioning device based on the magnetization characteristics in the embodiment of the present invention. Figure 2 In one embodiment of the present invention, a workpiece positioning device for a CNC lathe based on magnetization characteristics includes:

[0141] A magnetic field pre-scanning module 201 is used to pre-scan the surface of the workpiece to be transferred on the workstation, obtain magnetic field intensity distribution data on the workpiece surface, and obtain two optimal clamping points of the workpiece based on the magnetic field intensity distribution data;

[0142] The unstable region identification module 202 is used to process the magnetic field intensity distribution data, determine the average value of the magnetic field intensity of the two best clamping points as a reference value, mark the area where the circumferential magnetic field intensity variation exceeds a preset multiple of the reference value, and obtain the unstable region distribution data on the workpiece surface;

[0143] The magnetic moment analysis module 203 is used to perform magnetic moment analysis on the unstable region distribution data, and calculate the synthetic magnetic moment of each circumferential magnetized region of the workpiece based on the line connecting the two optimal clamping points, so as to obtain the optimal placement angle of the workpiece;

[0144] A support point determination module 204 is used to select, based on the optimal placement angle, an area on the workpiece surface where the angle between the two optimal clamping points is a preset angle and the magnetic field strength is the smallest as the first contact point, and select two points with the smallest magnetic field strength on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece;

[0145] The stability analysis module 205 is used to perform mechanical simulation analysis on the three-point support placement scheme, calculate the theoretical force value of each support point under the action of the workpiece's own weight, and analyze the force change trend of each support point after being affected by the magnetic force in combination with the unstable area distribution data. When the predicted force change rate exceeds the preset range, the three-point support placement scheme is recalculated until the predicted force change rate is within the preset range, thereby obtaining a stable state judgment result of the workpiece.

[0146] above Figure 2 The workpiece positioning device of a CNC lathe based on magnetization characteristics in an embodiment of the present invention is described in detail from the perspective of modular functional entities. The workpiece positioning system of a CNC lathe based on magnetization characteristics in an embodiment of the present invention is described in detail from the perspective of hardware processing.

[0147] Figure 3It is a structural schematic diagram of a CNC lathe workpiece positioning system based on magnetization characteristics provided by an embodiment of the present invention. The CNC lathe workpiece positioning system 300 based on magnetization characteristics may have relatively large differences due to different configurations or performances, and may include one or more processors (central processing units, CPU) 310 (for example, one or more processors) and a memory 320, and one or more storage media 330 (for example, one or more mass storage device terminals) storing application programs 333 or data 332. Among them, the memory 320 and the storage medium 330 can be short-term storage or permanent storage. The program stored in the storage medium 330 may include one or more modules (not shown in the figure), and each module may include a series of instruction operations in the CNC lathe workpiece positioning system 300 based on magnetization characteristics. Furthermore, the processor 310 can be configured to communicate with the storage medium 330, and execute a series of instruction operations in the storage medium 330 on the CNC lathe workpiece positioning system 300 based on magnetization characteristics to implement the steps of the CNC lathe workpiece positioning method based on magnetization characteristics.

[0148] The CNC lathe workpiece positioning system 300 based on magnetization characteristics may also include one or more power supplies 340, one or more wired or wireless network interfaces 350, one or more input and output interfaces 360, and / or one or more operating systems 331, such as Windows Serve, Mac OS X, Unix, Linux, FreeBSD, etc. Those skilled in the art will appreciate that Figure 3 The structure of the CNC lathe workpiece positioning system based on magnetic features shown does not constitute a limitation of the CNC lathe workpiece positioning system based on magnetic features provided by the present invention, and may include more or fewer components than shown in the figure, or a combination of certain components, or a different arrangement of components.

[0149] In some embodiments, see Figure 4 The workpiece positioning system of a CNC lathe based on magnetization characteristics has a CNC lathe 100, which includes a lathe mechanism 1, a loading bin 2, an electric box 3, a loading head 4, a loading window 5, a unloading window 6, a unloading head 7 and a unloading bin 8. Since these structures are relatively common structures, the operating principles of these structures will not be described in detail here.

[0150] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for positioning a workpiece of a CNC lathe based on magnetization characteristics, characterized in that: include: Pre-scanning the surface of the workpiece to be transferred on the workstation to obtain magnetic field intensity distribution data on the workpiece surface, and obtaining two optimal clamping points of the workpiece based on the magnetic field intensity distribution data; Processing the magnetic field intensity distribution data, determining the average value of the magnetic field intensity of the two best clamping points as a reference value, marking the area where the circumferential magnetic field intensity variation exceeds a preset multiple of the reference value, and obtaining the unstable area distribution data on the workpiece surface; The unstable region distribution data is subjected to magnetic moment analysis, and the synthetic magnetic moment of each magnetized region in the circumferential direction of the workpiece is calculated based on the line connecting the two optimal clamping points, so as to obtain the optimal placement angle of the workpiece; the magnetic moment analysis of the unstable region distribution data is subjected to magnetic moment analysis, and the synthetic magnetic moment of each magnetized region in the circumferential direction of the workpiece is calculated based on the line connecting the two optimal clamping points, so as to obtain the optimal placement angle of the workpiece, including: projecting the unstable region distribution data into a polar coordinate system with the line connecting the two optimal clamping points as the reference axis, so as to obtain the spatial distribution data of the magnetized region; discretizing the spatial distribution data of the magnetized region, dividing the circumferential direction of the workpiece into N sector regions, and calculating each sector region. The equivalent magnetization intensity of the sector area is obtained to obtain a circumferential magnetization intensity distribution sequence; according to the circumferential magnetization intensity distribution sequence, the sector area is divided into a strong magnetization area, a medium magnetization area and a weak magnetization area according to the magnetization intensity, and the center of gravity position of each area is calculated to obtain a magnetic moment calculation base point; with the reference axis as a reference, the magnetic moments generated by the strong magnetization area, the medium magnetization area and the weak magnetization area are calculated respectively to obtain the moment distribution characteristics of each magnetization area; based on the moment distribution characteristics, the synthetic magnetic moment of the workpiece at different angles is calculated to obtain a magnetic moment balance curve of the workpiece; according to the magnetic moment balance curve, the angle with the smallest synthetic magnetic moment and in a stable equilibrium position is selected as the optimal placement angle; Based on the optimal placement angle, an area on the workpiece surface where the angle between the line connecting the two optimal clamping points is a preset angle and the magnetic field strength is the smallest is selected as the first contact point, and two points with the smallest magnetic field strength are selected on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece; A mechanical simulation analysis is performed on the three-point support placement scheme to calculate the theoretical force value of each support point under the action of the workpiece's own weight. The force change trend of each support point after being affected by the magnetic force is analyzed in combination with the unstable area distribution data. When the predicted force change rate exceeds the preset range, the three-point support placement scheme is recalculated until the predicted force change rate is within the preset range, thereby obtaining a stable state judgment result of the workpiece.

2. The method for positioning a workpiece of a CNC lathe based on magnetization characteristics according to claim 1, characterized in that: The method of pre-scanning the surface of the workpiece to be transferred on the workstation to obtain magnetic field intensity distribution data on the workpiece surface, and obtaining two optimal clamping points of the workpiece based on the magnetic field intensity distribution data, includes: Performing a first magnetic field intensity scan within a preset time after the workpiece is processed to obtain initial magnetic field intensity distribution data on the workpiece surface; At a preset time interval after the first magnetic field strength scan is completed, performing a second magnetic field strength scan on the workpiece to obtain magnetic field strength distribution data under a residual heat state on the workpiece surface; Comparative analysis is performed on the initial magnetic field intensity distribution data and the magnetic field intensity distribution data under the residual heat state, and an area where the magnetic field intensity change rate on the workpiece surface is less than a preset threshold is determined as a magnetic field intensity stable area; In the magnetic field strength stable region, two points with a distance of 180°±5° and the smallest magnetic field strength are selected as the two optimal clamping points.

3. The method for positioning a workpiece of a CNC lathe based on magnetization characteristics according to claim 2 is characterized in that: The comparative analysis of the initial magnetic field intensity distribution data and the magnetic field intensity distribution data in the residual heat state to determine the area where the magnetic field intensity change rate on the workpiece surface is less than a preset threshold as a magnetic field intensity stable area includes: Divide the workpiece surface into a cutting zone, a non-cutting transition zone and an unprocessed zone, wherein the cutting zone is the area in direct contact with the tool, the non-cutting transition zone is the heat-affected zone within a range of no more than 5 mm outside the cutting zone, and the unprocessed zone is the remaining surface area away from the cutting zone; Performing orthogonal analysis on the initial magnetic field intensity distribution data of the cutting processing area and the magnetic field intensity distribution data under the residual heat state to obtain transient magnetic field change data of the cutting processing area; Performing harmonic analysis on the initial magnetic field intensity distribution data of the non-cutting transition zone and the magnetic field intensity distribution data in the residual heat state to obtain magnetic field variation period data of the non-cutting transition zone; Based on the transient magnetic field change data, determining the magnetic field influence radius of the cutting processing area, and screening out a first type of candidate area in the unprocessed area that exceeds the magnetic field influence radius; Based on the magnetic field variation period data, determining the thermal stress diffusion range of the non-cutting transition zone, and screening out a second type of candidate area that exceeds the thermal stress diffusion range from the first type of candidate areas; A difference analysis is performed on the initial magnetic field intensity distribution data of the second-category candidate area and the magnetic field intensity distribution data in the residual heat state, and an area where the difference is less than a preset threshold is determined as a magnetic field intensity stable area.

4. The method for positioning a workpiece of a CNC lathe based on magnetization characteristics according to claim 1, characterized in that: The data processing of the magnetic field intensity distribution data, determining the mean value of the magnetic field intensity of the two optimal clamping points as a reference value, marking the area where the circumferential magnetic field intensity change exceeds a preset multiple of the reference value, and obtaining the unstable area distribution data on the workpiece surface, includes: Taking the average magnetic field strength of the two best clamping points as a reference value, setting detection reference points every 30° around the workpiece to obtain circumferential magnetic field detection data on the workpiece surface; Performing circumferential Fourier decomposition on the circumferential magnetic field detection data, extracting frequency components therein, and marking a region where the high-frequency component exceeds a first preset threshold as a first type of magnetization abnormality region; Analyze the phase characteristics of the circumferential magnetic field detection data, and mark the area where the phase difference of adjacent detection points exceeds a second preset threshold as a second type of magnetization abnormality area; Calculating the magnetic field gradient of each detection point on the workpiece surface, marking the area where the magnetic field gradient exceeds the preset multiple of the reference value as the third type of magnetization abnormality area; Analyze the spatial distribution relationship between the first type of magnetization anomaly region, the second type of magnetization anomaly region, and the third type of magnetization anomaly region, and mark the connection area between adjacent areas as a magnetic field diffusion area; A union of the first type of abnormal magnetization region, the second type of abnormal magnetization region, the third type of abnormal magnetization region and the magnetic field diffusion region is determined as unstable region distribution data on the workpiece surface.

5. The method for positioning a workpiece of a CNC lathe based on magnetization characteristics according to claim 4 is characterized in that: The performing circumferential Fourier decomposition on the circumferential magnetic field detection data, extracting the frequency components therein, and marking the area where the high-frequency components exceed the first preset threshold as the first type of magnetization abnormal area, comprises: Expanding the circumferential magnetic field detection data according to a sampling point sequence to construct a discrete sequence of magnetic field intensity; Performing window function smoothing on the discrete sequence of magnetic field intensity to eliminate the influence of endpoint mutation on spectrum analysis; Perform fast Fourier transform on the smoothed sequence to obtain the frequency spectrum distribution characteristics of the magnetic field intensity; Based on the spectrum distribution characteristics, calculating the energy contribution rate of each frequency component, and defining the frequency component whose energy contribution rate exceeds a first preset threshold as an abnormal frequency component; According to the amplitude distribution of the abnormal frequency component in the original magnetic field detection data, the area where the amplitude exceeds the first preset threshold is marked as a first type of magnetization abnormality area.

6. The method for positioning a workpiece of a CNC lathe based on magnetization characteristics according to claim 1, characterized in that: Based on the optimal placement angle, an area on the workpiece surface with a preset angle to the line connecting the two optimal clamping points and with the smallest magnetic field strength is selected as the first contact point, and two points with the smallest magnetic field strength are selected on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece, including: An angular coordinate system with the optimal placement angle as the starting direction is established on the workpiece surface, and the angle of the line connecting the two optimal clamping points is set to 0° to obtain angular positioning data of the workpiece surface; Performing regional segmentation on the angle positioning data, dividing the workpiece surface into a plurality of sector-shaped search areas with an angle of 15°, calculating the average magnetic field intensity in each search area, and obtaining a magnetic field intensity distribution map of the workpiece surface; In the magnetic field intensity distribution map, a sector-shaped search area with an angle of 90°±15° with the line connecting the two optimal clamping points is marked, and an area with the smallest magnetic field intensity is selected as a candidate area for first contact; Finely scan the candidate area for first contact, reacquire magnetic field strength data at intervals of 5°, and select the point with the smallest magnetic field strength as the first contact point; Taking the first contact point as the center, within the range of 120°±10° on both sides thereof, select the point with the smallest magnetic field intensity as the auxiliary support candidate point; A force balance analysis is performed on the candidate auxiliary support points, and two points with the most uniform force are selected as the auxiliary support points to obtain the three-point support placement plan.

7. The method for positioning a workpiece of a CNC lathe based on magnetization characteristics according to claim 1, characterized in that: The mechanical simulation analysis is performed on the three-point support placement scheme, the theoretical force value of each support point under the deadweight of the workpiece is calculated, and the force change trend of each support point after being affected by the magnetic force is analyzed in combination with the unstable area distribution data. When the predicted force change rate exceeds the preset range, the three-point support placement scheme is recalculated until the predicted force change rate is within the preset range, and the stable state determination result of the workpiece is obtained, including: According to the weight distribution parameters of the workpiece and the geometric position relationship of the three-point support, the static force components of each support point are calculated; Based on the unstable area distribution data, analyzing the torque contribution of the magnetized area around each support point to the support point to obtain magnetic induced torque data; Performing vector superposition of the static force component and the magnetic induced torque data to obtain a predicted value of the resultant force of each support point; Calculating the deviation rate of the predicted value of the resultant force relative to the static force component and comparing it with a preset stability threshold; When the deviation rate of any support point exceeds the stability threshold, return to the step of "based on the optimal placement angle, select an area on the workpiece surface with a preset angle to the line connecting the two optimal clamping points and with the smallest magnetic field strength as the first contact point, and select two points with the smallest magnetic field strength on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece" and recalculate the three-point support placement plan until the deviation rates of all support points are less than the stability threshold, and output the final stable state judgment result.

8. A workpiece positioning device for a CNC lathe based on magnetization characteristics, characterized in that: The CNC lathe workpiece positioning device based on magnetization characteristics is applied to the CNC lathe workpiece positioning method based on magnetization characteristics as claimed in any one of claims 1 to 7, comprising: A magnetic field pre-scanning module is used to pre-scan the surface of the workpiece to be transferred on the workstation, obtain magnetic field intensity distribution data on the workpiece surface, and obtain two optimal clamping points of the workpiece based on the magnetic field intensity distribution data; An unstable region identification module is used to process the magnetic field intensity distribution data, determine the average value of the magnetic field intensity of the two best clamping points as a reference value, mark the region where the circumferential magnetic field intensity variation exceeds a preset multiple of the reference value, and obtain the unstable region distribution data on the workpiece surface; The magnetic moment analysis module is used to perform magnetic moment analysis on the unstable region distribution data, and calculate the synthetic magnetic moment of each magnetized region in the circumferential direction of the workpiece based on the line connecting the two optimal clamping points, so as to obtain the optimal placement angle of the workpiece; the magnetic moment analysis on the unstable region distribution data, and calculate the synthetic magnetic moment of each magnetized region in the circumferential direction of the workpiece based on the line connecting the two optimal clamping points, so as to obtain the optimal placement angle of the workpiece, including: projecting the unstable region distribution data into a polar coordinate system with the line connecting the two optimal clamping points as the reference axis to obtain the spatial distribution data of the magnetized region; discretizing the spatial distribution data of the magnetized region to divide the circumferential direction of the workpiece into N sector-shaped regions , calculate the equivalent magnetization intensity of each sector area to obtain a circumferential magnetization intensity distribution sequence; according to the circumferential magnetization intensity distribution sequence, divide the sector area into a strong magnetization area, a medium magnetization area and a weak magnetization area according to the magnetization intensity, calculate the center of gravity position of each area, and obtain the magnetic moment calculation base point; with the reference axis as a reference, calculate the magnetic moment generated by the strong magnetization area, the medium magnetization area and the weak magnetization area respectively, and obtain the moment distribution characteristics of each magnetization area; based on the moment distribution characteristics, calculate the synthetic magnetic moment of the workpiece at different angles to obtain the magnetic moment balance curve of the workpiece; according to the magnetic moment balance curve, select the angle with the smallest synthetic magnetic moment and in a stable equilibrium position as the optimal placement angle; A support point determination module is used to select, based on the optimal placement angle, an area on the workpiece surface where the angle between the two optimal clamping points is a preset angle and the magnetic field strength is the smallest as the first contact point, and select two points with the smallest magnetic field strength on both sides of the first contact point as auxiliary support points to obtain a three-point support placement plan for the workpiece; The stability analysis module is used to perform mechanical simulation analysis on the three-point support placement scheme, calculate the theoretical force value of each support point under the action of the workpiece's own weight, and analyze the force change trend of each support point after being affected by the magnetic force in combination with the unstable area distribution data. When the predicted force change rate exceeds the preset range, the three-point support placement scheme is recalculated until the predicted force change rate is within the preset range, thereby obtaining a stable state judgment result of the workpiece.

9. A workpiece positioning system for a CNC lathe based on magnetization characteristics, characterized in that: The CNC lathe workpiece positioning system based on magnetization characteristics comprises: a memory and at least one processor, wherein instructions are stored in the memory; The at least one processor calls the instructions in the memory to enable the CNC lathe workpiece positioning system based on magnetization features to execute the steps of the CNC lathe workpiece positioning method based on magnetization features as described in any one of claims 1-7.

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