Multi-axis cooperation method for industrial master

Abstract

The invention relates to the technical field of industrial master machine multi-axis coordination, and particularly discloses an industrial master machine multi-axis coordination method, which comprises the following steps of: selecting thermomagnetic sheets with thermomagnetic coupling characteristics, respectively embedding the thermomagnetic sheets into key parts of corresponding motion axes of a multi-axis machine tool, and simultaneously installing a high-precision magnetic field sensor in a main shaft of the multi-axis machine tool, the receiving module is used for receiving a magnetic field vector of each motion axis in each monitoring time point; collecting the temperature of each motion shaft in each monitoring time point, and calculating the thermal deformation amount of each motion shaft corresponding to the next time point; therefore, each motion shaft is dynamically judged and analyzed, and finally, the position compensation of each motion shaft corresponding to the next time point is realized, so that the machining precision and efficiency of the multi-shaft machine tool are improved, and the reliability, maintainability and intelligent level of the system are enhanced. The application of the technology has important practical significance and development potential in the modern manufacturing industry, and is a necessary means for realizing efficient, precise and intelligent manufacturing.

Description

Technical Field

[0001] The invention belongs to the technical field of multi-axis coordination of industrial machine tools and relates to a multi-axis coordination method of industrial machine tools. Background Art

[0002] In modern manufacturing, thermal deformation compensation of industrial machine tools is particularly important and necessary. With the continuous improvement of machining accuracy requirements, thermal deformation has become one of the key factors affecting product quality. During the operation of industrial machine tools, the heat generated by friction, cutting and other factors will cause the expansion of machine tool components, thereby causing changes in geometric shape, which directly affects the machining accuracy and surface quality. The effective implementation of thermal deformation compensation can offset the errors caused by thermal deformation by real-time monitoring and dynamic adjustment of the position instructions of the machine tool, thereby ensuring the stability and consistency of the machining process. In addition, thermal deformation compensation not only helps to improve the product qualification rate and reduce the scrap rate, but also prolong the service life of the machine tool and reduce maintenance costs. Therefore, the development of effective thermal deformation compensation technology has become a key link in improving the performance of industrial machine tools, especially in high-precision and high-complexity machining tasks, its importance is becoming more and more prominent.

[0003] However, current technologies still have many defects and drawbacks in the thermal deformation compensation of industrial machine tools. First, many compensation technologies rely on static models and empirical formulas, which makes the compensation effect less adaptable under different working conditions. Traditional compensation methods are often adjusted based on historical data, but fail to take into account real-time temperature changes and load conditions, resulting in delayed compensation effects and inability to effectively cope with rapidly changing thermal conditions.

[0004] Secondly, traditional thermal deformation monitoring usually relies on temperature sensors and displacement sensors, but these sensors are easily disturbed under high temperature or high load conditions, resulting in inaccurate data. This inaccuracy directly affects the performance of the compensation algorithm, which in turn affects the overall machining accuracy of the machine tool. In addition, the maintenance and calibration of the sensor also increase the complexity and cost of the system, especially in a large-scale production environment, where frequent maintenance may lead to a decrease in production efficiency. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention provides an industrial mother machine multi-axis coordination method for solving the above technical problems.

[0006] In order to achieve the above purpose and other purposes, the technical solution adopted by the present invention is as follows: The present invention provides a multi-axis coordination method for an industrial machine tool, the method comprising the following steps: A thermomagnetic sheet with thermomagnetic coupling characteristics is selected, and the thermomagnetic sheet is respectively embedded in the key parts of each motion axis of the multi-axis machine tool, and a high-precision magnetic field sensor is installed in the main axis of the multi-axis machine tool, which is used to receive the magnetic field vector of each motion axis at each monitoring time point; The temperature of each moving axis at each monitoring time point is collected, and the thermal deformation of each moving axis corresponding to the next time point is calculated; thus, dynamic judgment and analysis of each moving axis are performed, and finally the position compensation of each moving axis corresponding to the next time point is achieved.

[0007] The magnetic field vector of each motion axis at each monitoring time point is obtained as follows: Based on the magnetic field vectors of each thermomagnetic sheet at each monitoring time point collected by the high-precision magnetic field sensor, the embedded position of each thermomagnetic sheet is corresponded to the position of each motion axis, so that the magnetic field vector of each thermomagnetic sheet at each monitoring time point is recorded as the magnetic field vector corresponding to each motion axis at each monitoring time point.

[0008] The receiving logic for receiving the magnetic field vector of each motion axis at each monitoring time point is: The spindle of the multi-axis machine tool is set as the Y-axis, the horizontal direction on the multi-axis machine tool workbench and the direction perpendicular to the Y-axis is set as the X-axis, and the direction perpendicular to the XY plane is set as the Z-axis. The three-dimensional coordinates of the thermal magnetic sheet in the key parts corresponding to each motion axis are collected and recorded as the three-dimensional coordinates of each thermal magnetic sheet. ; r is the serial number of each thermal magnetic sheet, r=1,2,..., R,R is the total number of thermal magnetic sheets; Collect experimental data through experimental calibration in advance, where the experimental data includes the rth thermal magnetic sheet at the reference temperature The reference magnetic moment , Linear Temperature Coefficient and nonlinear temperature coefficient ; Based on the R magnetic field vectors collected by the high-precision magnetic field sensor at each monitoring time point, a thermal magnetic sheet is randomly selected from each thermal magnetic sheet as the target thermal magnetic sheet, and the R magnetic field vectors at each monitoring time point are respectively assumed to be the magnetic field vectors of the target thermal magnetic sheet at each monitoring time point; The estimated magnetic moment value corresponding to the rth magnetic field vector of the target thermal magnetic sheet at each monitoring time point is calculated from this , is the rth magnetic field vector of the target thermal magnetic sheet at the tth monitoring time point, JL is the distance between the target thermal magnetic sheet and the high-precision magnetic field sensor, , (x, y, z) is the three-dimensional coordinate of the target thermal magnetic sheet; k is the set proportional coefficient related to JL, , is the magnetic permeability in vacuum; t is the number of each monitoring time point, t=1,2,..., T,T is the total observation time of the monitoring time point, represents the norm symbol; By calculating the matching degree between the estimated magnetic moment value corresponding to the rth magnetic field vector of the target thermal magnetic sheet and the theoretical magnetic moment value corresponding to the target thermal magnetic sheet ,in is the estimated mean value of the magnetic moment of the target thermal magnetic sheet corresponding to the rth magnetic field vector, , is the theoretical magnetic moment value of the target thermal magnetic sheet at the tth monitoring time point, is the theoretical magnetic moment mean value of the target thermal magnetic sheet at all monitoring time points, ; Arrange the matching degrees in descending order, select the magnetic field vector with the highest matching degree as the magnetic field vector of the target thermal magnetic sheet corresponding to each monitoring time point, thereby obtaining the magnetic field vector of the target thermal magnetic sheet corresponding to each monitoring time point; Based on the correspondence between the embedded position of the target thermal magnetic sheet and the position of each motion axis, the magnetic field vector of the motion axis to which the corresponding embedded position of the target thermal magnetic sheet belongs at each monitoring time point is obtained; and based on its analysis method, the magnetic field vector of the motion axis to which the corresponding embedded position of each thermal magnetic sheet belongs at each monitoring time point is obtained, and finally the magnetic field vector of each motion axis at each monitoring time point is obtained.

[0009] The calculation logic of the theoretical magnetic moment value of the target thermal magnetic sheet corresponding to each monitoring time point is: The expected temperature of the target thermal magnetic sheet at each monitoring time point is inferred by using the calibrated linear temperature coefficient α of the target thermal magnetic sheet. , The target thermal magnetic sheet is at a reference temperature The base magnetic moment under is the estimated mean value of the magnetic moment of the target thermal magnetic sheet at the tth monitoring time point, ; The theoretical magnetic moment value of the target thermal magnetic sheet corresponding to each monitoring time point is calculated accordingly. , where β is the nonlinear temperature coefficient of the target thermomagnetic sheet.

[0010] Calculate the thermal deformation of each motion axis at the next time point. The specific calculation formula is shown as follows: The temperature of each motion axis is displayed at each monitoring time point on the multi-axis machine tool display screen. The temperature of each motion axis at the current time point is extracted. ; i is the number of each motion axis; Based on the magnetic field vector of each motion axis at the current time point , , calculate the thermal deformation of each motion axis at the next time point ; In the above formula They represent the thermal expansion coefficient, thermal inertia coefficient and magnetic field coupling coefficient of the material corresponding to the i-th motion axis, respectively. is the thermal sensitive length of the i-th motion axis, t' is the current time point, △t is the time difference step between the current time point and the next time point, , is the temperature of each motion axis at the previous time point at the time difference step from the current time point, , is the magnetic field vector amplitude of each motion axis at the current time point.

[0011] Perform dynamic judgment and analysis on each motion axis, including: The thermal deformation amount of each motion axis corresponding to the next time point is compared with the preset threshold of the multi-axis machine tool. If the thermal deformation amount of a motion axis corresponding to the next time point is greater than the preset threshold of the multi-axis machine tool, the high heat mode is executed for the motion axis, otherwise the low heat mode is executed for the motion axis.

[0012] The process of setting the preset threshold for multi-axis machine tools is as follows: , Preset thresholds for multi-axis machines, is the set minimum sensitivity threshold, and IT Grade is the machine accuracy grade of the multi-axis machine tool.

[0013] The motion axis executing the high heat mode is recorded as the first compensation motion axis, and the position compensation process of each first compensation motion axis corresponding to the next time point is: By calculating the formula , calculate the position compensation amount of each first compensation motion axis corresponding to the next time point , p is the number of each first compensation motion axis, k1 is the set proportional gain value, k2 is the set differential gain value, They represent the thermal deformation of the pth first compensation motion axis at the next time point and the thermal deformation at the current time point, respectively. represents the basic compensation amount of the pth first compensation motion axis; The position compensation amount of each first compensating motion axis corresponding to the next time point is used as the denominator of the fraction, and the transmission ratio of each first compensating motion axis at the current time point is used as the numerator of the fraction. The fraction is solved to obtain the rotation arc of the motor of each first compensating motion axis corresponding to the next time point, and the corresponding rotation arc instruction is sent to the motor of each first compensating motion axis for position compensation.

[0014] The motion axis executing the low heat mode is recorded as the second compensation motion axis, and the position compensation process of each second compensation motion axis corresponding to the next time point is: By calculating the formula , calculate the position compensation amount of each second compensation motion axis corresponding to the next time point , q is the number of each second compensation motion axis, k3 is the set small range proportional gain, k3=0.2k1; k4 is the set integral gain, , τ is the integration time constant, g is the loop index, which indicates the number of steps used for integration and summation; n is the number of steps in the integration window, is the qth second compensation motion axis at time The thermal deformation, They respectively represent the thermal deformation of the qth second compensatory motion axis at the next time point; The position compensation amount of each second compensating motion axis corresponding to the next time point is used as the denominator of the fraction, and the transmission ratio of each second compensating motion axis at the current time point is used as the numerator of the fraction. The fraction is solved to obtain the rotation arc of the motor of each second compensating motion axis corresponding to the next time point, and the corresponding rotation arc instruction is sent to the motor of each second compensating motion axis for position compensation.

[0015] As described above, the multi-axis coordination method of an industrial machine tool provided by the present invention has at least the following beneficial effects: The present invention provides a multi-axis collaborative method for an industrial mother machine, which can monitor the temperature changes and corresponding magnetic field vectors of each moving axis in real time through the non-contact thermal deformation compensation technology and the thermal magnetic coupling characteristics. This monitoring method avoids the mechanical interference and wear problems that may be caused by traditional contact sensors, and improves the reliability and stability of the system. Since the thermal magnetic sheet can directly reflect the impact of temperature changes on the magnetic field, it provides a more accurate calculation of thermal deformation and ensures the accuracy of the compensation data. This real-time and accuracy is crucial for high-precision machining of multi-axis machine tools, and can effectively reduce machining errors caused by thermal deformation; Secondly, the data collected by high-precision magnetic field sensors can be used to dynamically judge and analyze the position of each moving axis. By combining the temperature and magnetic field vectors of different moving axes, the system can quickly calculate the thermal deformation of each moving axis at the next point in time, so as to make timely compensation. This real-time response capability significantly improves the processing efficiency of machine tools, can effectively prevent poor processing caused by thermal deformation, and ensure the consistency of product quality; In summary, the selection of thermal magnetic sheets with thermal magnetic coupling characteristics and the combination of high-precision magnetic field sensors to achieve non-contact thermal deformation compensation not only improves the machining accuracy and efficiency of multi-axis machine tools, but also enhances the reliability, maintainability and intelligence level of the system. The application of this technology has important practical significance and development potential in modern manufacturing, and is a necessary means to achieve efficient, precise and intelligent manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the connection of each step of the method of the present invention; Figure 2 A three-dimensional schematic diagram of a multi-axis machine tool of the present invention; Figure 3 It is a partially enlarged schematic diagram of the thermal magnetic sheet in the multi-axis machine tool of the present invention. DETAILED DESCRIPTION

[0018] The above contents in combination with the implementation of the present invention are merely examples and explanations of the concept of the present invention. The technical personnel in the relevant technical field may make various modifications or supplements to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

[0019] Example 1 See also Figure 1-Figure 3 As shown, a multi-axis coordination method for an industrial machine tool comprises the following steps: A thermomagnetic sheet with thermomagnetic coupling characteristics is selected, and the thermomagnetic sheet is respectively embedded in the key parts of each motion axis of the multi-axis machine tool, and a high-precision magnetic field sensor is installed in the main axis of the multi-axis machine tool, which is used to receive the magnetic field vector of each motion axis at each monitoring time point; The magnetic field vector of each motion axis at each monitoring time point is obtained as follows: Based on the magnetic field vectors of each thermomagnetic sheet at each monitoring time point collected by the high-precision magnetic field sensor, the embedded position of each thermomagnetic sheet is corresponded to the position of each motion axis, so that the magnetic field vector of each thermomagnetic sheet at each monitoring time point is recorded as the magnetic field vector corresponding to each motion axis at each monitoring time point.

[0020] The receiving logic for receiving the magnetic field vector of each motion axis at each monitoring time point is: The spindle of the multi-axis machine tool is set as the Y-axis, the horizontal direction on the multi-axis machine tool workbench and the direction perpendicular to the Y-axis is set as the X-axis, and the direction perpendicular to the XY plane is set as the Z-axis. The three-dimensional coordinates of the thermal magnetic sheet in the key parts corresponding to each motion axis are collected and recorded as the three-dimensional coordinates of each thermal magnetic sheet. ; r is the serial number of each thermal magnetic sheet, r=1,2,..., R,R is the total number of thermal magnetic sheets; Collect experimental data through experimental calibration in advance, where the experimental data includes the rth thermal magnetic sheet at the reference temperature The reference magnetic moment , Linear Temperature Coefficient and nonlinear temperature coefficient ; The linear temperature coefficient is the ratio of magnetic moment change for every 1°C increase in temperature; Based on the R magnetic field vectors collected by the high-precision magnetic field sensor at each monitoring time point, a thermal magnetic sheet is randomly selected from each thermal magnetic sheet as the target thermal magnetic sheet, and the R magnetic field vectors at each monitoring time point are respectively assumed to be the magnetic field vectors of the target thermal magnetic sheet at each monitoring time point; The estimated magnetic moment value corresponding to the rth magnetic field vector of the target thermal magnetic sheet at each monitoring time point is calculated from this , is the rth magnetic field vector of the target thermal magnetic sheet at the tth monitoring time point, JL is the distance between the target thermal magnetic sheet and the high-precision magnetic field sensor, , (x, y, z) is the three-dimensional coordinate of the target thermal magnetic sheet, which is extracted from the three-dimensional coordinate of each thermal magnetic sheet; k is the set proportional coefficient related to JL, , is the magnetic permeability in vacuum; t is the number of each monitoring time point, t=1,2,..., T,T is the total observation time of the monitoring time point, represents the norm symbol; In the above calculation formula, k is a constant used to establish a relationship between the measured magnetic field strength and the magnetic moment of the hot magnetic sheet. It is a proportionality coefficient related to the distance JL; as a proportionality constant, k can help relate the magnetic field strength to the magnetic moment or other related parameters. Specifically, it takes into account the cubic relationship of the distance when calculating the impact of the magnetic field, because the magnetic field strength usually decreases rapidly with increasing distance. By introducing this constant, the relationship between the magnetic field and the hot magnetic sheet can be described more accurately; is the magnetic permeability in vacuum, which is approximately (Tesla meter / ampere). It is a physical constant that describes the propagation characteristics of a magnetic field in a vacuum. Magnetic permeability is the ability of a material to respond to a magnetic field. This is the baseline value in the absence of any substance.

[0021] By calculating the matching degree between the estimated magnetic moment value corresponding to the rth magnetic field vector of the target thermal magnetic sheet and the theoretical magnetic moment value corresponding to the target thermal magnetic sheet ,in is the estimated mean value of the magnetic moment of the target thermal magnetic sheet corresponding to the rth magnetic field vector, , is the theoretical magnetic moment value of the target thermal magnetic sheet at the tth monitoring time point, is the theoretical magnetic moment mean value of the target thermal magnetic sheet at all monitoring time points, ; Arrange the matching degrees in descending order, select the magnetic field vector with the highest matching degree as the magnetic field vector of the target thermal magnetic sheet corresponding to each monitoring time point, thereby obtaining the magnetic field vector of the target thermal magnetic sheet corresponding to each monitoring time point; Based on the correspondence between the embedded position of the target thermal magnetic sheet and the position of each motion axis, the magnetic field vector of the motion axis to which the corresponding embedded position of the target thermal magnetic sheet belongs at each monitoring time point is obtained; and based on its analysis method, the magnetic field vector of the motion axis to which the corresponding embedded position of each thermal magnetic sheet belongs at each monitoring time point is obtained, and finally the magnetic field vector of each motion axis at each monitoring time point is obtained.

[0022] The calculation logic of the theoretical magnetic moment value of the target thermal magnetic sheet corresponding to each monitoring time point is: The expected temperature of the target thermal magnetic sheet at each monitoring time point is inferred by using the calibrated linear temperature coefficient α of the target thermal magnetic sheet. , The target thermal magnetic sheet is at a reference temperature The base magnetic moment under is the estimated mean value of the magnetic moment of the target thermal magnetic sheet at the tth monitoring time point, ; The theoretical magnetic moment value of the target thermal magnetic sheet corresponding to each monitoring time point is calculated accordingly. , where β is the nonlinear temperature coefficient of the target thermomagnetic sheet.

[0023] The magnetic properties of thermomagnetic materials usually change with temperature. There is a certain linear relationship between the magnetic moment and temperature of many thermomagnetic materials, which is the source of the linear temperature coefficient α. In addition, with further changes in temperature, the magnetic properties of the material may show nonlinear behavior, so it is necessary to introduce a nonlinear temperature coefficient β. This phenomenon has been reported in many literatures. For example, in the study of ferromagnetic materials and certain alloys, the effect of temperature changes on magnetic properties has been widely experimentally verified; Through experimental calibration, the magnetic moment data of a specific material at different temperatures can be obtained. These data can be used to determine the linear and nonlinear temperature coefficients, thereby providing the necessary parameter support for the formula. For example, using a device such as a vibrating sample magnetometer (VSM), the magnetic properties of the material can be measured at different temperatures, and the values ​​of α and β can be fitted.

[0024] By using this formula, the change in the magnetic moment of the hot magnetic sheet in the working environment can be predicted more accurately. This is crucial for the control system of multi-axis machine tools, because accurate magnetic moment information can help the system to compensate for thermal deformation more effectively. This formula allows the theoretical magnetic moment to be adjusted dynamically when the temperature changes, thereby reflecting the state of the hot magnetic sheet in real time.

[0025] The temperature of each moving axis at each monitoring time point is collected, and the thermal deformation of each moving axis corresponding to the next time point is calculated; thus, dynamic judgment and analysis of each moving axis are performed, and finally the position compensation of each moving axis corresponding to the next time point is achieved.

[0026] The temperature of each moving axis at each monitoring time point can be collected by pasting or embedding a micro-thermistor (such as MF58 package) into the groove on the surface of each moving axis. The voltage signal is converted into a voltage signal through a Wheatstone bridge circuit and connected to an ADC module, thereby collecting the temperature of each moving axis at each monitoring time point.

[0027] Calculate the thermal deformation of each motion axis at the next time point. The specific calculation formula is shown as follows: The temperature of each motion axis is displayed at each monitoring time point on the multi-axis machine tool display screen. The temperature of each motion axis at the current time point is extracted. ; i is the number of each motion axis; Based on the magnetic field vector of each motion axis at the current time point , , calculate the thermal deformation of each motion axis at the next time point ; In the above formula They represent the thermal expansion coefficient, thermal inertia coefficient and magnetic field coupling coefficient of the material corresponding to the i-th motion axis, respectively. is the thermal sensitive length of the i-th motion axis, t' is the current time point, △t is the time difference step between the current time point and the next time point, , is the temperature of each motion axis at the previous time point at the time difference step from the current time point, , is the magnetic field vector amplitude of each motion axis at the current time point.

[0028] It indicates the expansion per unit length when the temperature rises by 1 degree Celsius; Reflects the hysteresis effect of material temperature change rate on thermal deformation. , They represent the material density, material specific heat capacity and material thermal conductivity of the material corresponding to the i-th motion axis respectively; represents the secondary effect of the magnetic field energy corresponding to the i-th motion axis on thermal deformation, , c4 and c5 represent the magnetic permeability and magnetic susceptibility of the hot magnetic sheet, respectively. is the material elastic modulus of the material corresponding to the i-th motion axis.

[0029] The first term in the above thermal deformation calculation formula reflects the thermal expansion effect of the material at the current temperature. It is a physical property of the material, usually measured experimentally, and represents the change in length of the material under a unit temperature change. According to the principles of thermodynamics, materials expand when the temperature rises, so this term is the basis for calculating thermal deformation. The second term takes into account the effect of the temperature change rate on the thermal deformation of the material. The temperature change rate is an important dynamic parameter that can affect the thermal response characteristics of the material. The introduction of this term allows the formula to adapt to rapidly changing operating environments, especially in high-frequency processing or rapid switching processes, the effect of the temperature change rate on thermal deformation is more significant. The third term represents the contribution of magnetic field energy to thermal deformation. The thermomagnetic coupling effect shows that the thermal expansion characteristics of certain materials will change under the action of a magnetic field. The introduction of this term allows the formula to not only consider the influence of temperature, but also integrate the effect of the magnetic field, which is very important in the application of thermomagnetic materials, especially in modern high-precision machine tools.

[0030] The above calculation formula can comprehensively consider the influence of multiple factors on thermal deformation and improve the accuracy of thermal deformation prediction. Especially in multi-axis machine tools, since the temperature changes and magnetic field changes during the processing are dynamic, the traditional thermal deformation calculation method often cannot respond to these changes quickly. By calculating the thermal deformation in real time, the control strategy of the machine tool can be adjusted in time to ensure processing accuracy and product quality.

[0031] Perform dynamic judgment and analysis on each motion axis, including: The thermal deformation amount of each motion axis corresponding to the next time point is compared with the preset threshold of the multi-axis machine tool. If the thermal deformation amount of a motion axis corresponding to the next time point is greater than the preset threshold of the multi-axis machine tool, the high heat mode is executed for the motion axis, otherwise the low heat mode is executed for the motion axis.

[0032] The process of setting the preset threshold for multi-axis machine tools is as follows: , Preset thresholds for multi-axis machines, is the set minimum sensitivity threshold, and IT Grade is the machine accuracy grade of the multi-axis machine tool.

[0033] The motion axis executing the high heat mode is recorded as the first compensation motion axis, and the position compensation process of each first compensation motion axis corresponding to the next time point is: By calculating the formula , calculate the position compensation amount of each first compensation motion axis corresponding to the next time point , p is the number of each first compensation motion axis, k1 is the set proportional gain value, k2 is the set differential gain value, Respectively represent the thermal deformation amount of the pth first compensation motion axis corresponding to the next time point and the thermal deformation amount at the current time point; Indicates the basic compensation amount of the pth first compensation motion axis. This value is a constant used to offset the deformation caused by long-term thermal drift or steady-state error. It is usually obtained through experiments or calibration under constant temperature conditions to ensure that the system can still maintain high accuracy in the absence of dynamic changes; The position compensation amount of each first compensating motion axis corresponding to the next time point is used as the denominator of the fraction, and the transmission ratio of each first compensating motion axis at the current time point is used as the numerator of the fraction. The fraction is solved to obtain the rotation arc of the motor of each first compensating motion axis corresponding to the next time point, and the corresponding rotation arc command is sent to the motor of each first compensating motion axis for position compensation. The rotation arc of the motor of each first compensating motion axis corresponding to the next time point is the motor motion command adjusted to compensate for the geometric error caused by thermal deformation. By correcting the command position, the system can ensure that the motion axis reaches the expected position during actual movement, thereby improving the processing accuracy.

[0034] The transmission ratio of each first compensating motion axis at the current time point represents the linear displacement caused by each rotation of the motor by one arc; and if the rotation arc of the motor of each first compensating motion axis corresponding to the next time point is a negative value, it means that the motor needs to rotate in the reverse direction, otherwise it means forward rotation.

[0035] The above calculation formula is for the dynamic compensation amount of the pth motion axis, which adopts the proportional-differential (PD) control strategy. The design of this formula is based on the classical control method in control theory, which aims to adjust the motion command of the servo motor through real-time feedback to offset the geometric error caused by thermal deformation: The existence of the first term, the proportional term, is based on linear control theory. The proportional gain k1 is obtained through experimental calibration and can effectively establish a linear relationship between the deformation and the compensation. Specifically, the selection of the proportional gain usually depends on the dynamic response characteristics of the system to ensure that when the deformation increases, the compensation can quickly keep up, thereby reducing the error; Secondly, the second differential term is used to suppress the rapid changes of the system and prevent overcompensation or oscillation. The introduction of differential gain k2 is to improve the stability of the system, especially in the face of rapid changes in thermal deformation, by feedback on the deformation rate, timely adjust the compensation amount to ensure smooth operation of the system.

[0036] Basic compensation items The purpose is to compensate for the steady-state error caused by environmental factors (such as temperature drift). Through calibration under constant temperature conditions, this baseline compensation can be determined to enhance the robustness of the system. The advantage of this calculation method is that it can respond to changes in thermal deformation in real time, ensure processing accuracy, and reduce workpiece dimensional deviations caused by thermal deformation. Especially in the field of high-precision processing, such as aerospace, mold manufacturing, etc., the requirements for processing accuracy are extremely high, and real-time compensation strategies are particularly important. In addition, the use of PD control strategy enables the system to achieve a good balance between dynamic response and stability, which can effectively reduce error accumulation during processing and improve production efficiency.

[0037] The motion axis executing the low heat mode is recorded as the second compensation motion axis, and the position compensation process of each second compensation motion axis corresponding to the next time point is: By calculating the formula , calculate the position compensation amount of each second compensation motion axis corresponding to the next time point , q is the number of each second compensation motion axis, k3 is the set small range proportional gain, k3=0.2k1; k4 is the set integral gain, , τ is the integration time constant, g is the loop index, which indicates the number of steps used for integration and summation; n is the number of steps in the integration window, is the qth second compensation motion axis at time The thermal deformation They respectively represent the thermal deformation of the qth second compensatory motion axis at the next time point; g is an index used to indicate the number of steps of integral summation. It cycles from 1 to n, indicating the thermal deformation at multiple time points after the current time point t'. Specifically, g indicates the number of time steps forward based on the current time point t'. For example, if Δt is set as the time step, then It is the moment after the current time point plus g time steps.

[0038] The position compensation amount of each second compensating motion axis corresponding to the next time point is used as the denominator of the fraction, and the transmission ratio of each second compensating motion axis at the current time point is used as the numerator of the fraction. The fraction is solved to obtain the rotation arc of the motor of each second compensating motion axis corresponding to the next time point, and the corresponding rotation arc instruction is sent to the motor of each second compensating motion axis for position compensation.

[0039] The proportional term of the first term in the above calculation formula enables the system to respond quickly to real-time changes in thermal deformation. When the thermal deformation increases, the compensation amount also increases, ensuring that the machine tool can adjust its position in time during the processing and reduce the processing error caused by thermal deformation. This real-time performance is particularly important in high-precision processing and can effectively reduce the defective rate of products; The introduction of the second integral term can effectively eliminate the steady-state error of the system. By accumulating the historical deformation, the integral term can compensate for the persistent small errors, ensuring that the position of the machine tool remains in an ideal state after long-term operation.

[0040] The parameters k3 and k4 in the formula can be calibrated according to different machine tools and processing conditions, which provides flexibility for the adaptability of the system. Engineers can obtain the optimal parameters through experiments, so that the compensation strategy can be optimized for specific machine tool characteristics and processing requirements, thereby improving processing accuracy and efficiency. It not only improves the machine tool's ability to cope with thermal deformation, but also optimizes the stability and accuracy during the processing. Through effective dynamic compensation, the overall processing quality is finally improved, the defects caused by thermal deformation are reduced, and the reliability and production efficiency of the machine tool are enhanced.

[0041] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0042] It should be understood that determining B based on A does not mean determining B only based on A. B can also be determined based on A and / or other information.

[0043] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0044] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-axis coordination method for an industrial machine tool, characterized in that: include: A thermomagnetic sheet with thermomagnetic coupling characteristics is selected, and the thermomagnetic sheet is respectively embedded in the key parts of each motion axis of the multi-axis machine tool, and a high-precision magnetic field sensor is installed in the main axis of the multi-axis machine tool, which is used to receive the magnetic field vector of each motion axis at each monitoring time point; The temperature of each moving axis at each monitoring time point is collected, and the thermal deformation of each moving axis corresponding to the next time point is calculated; thus, dynamic judgment and analysis of each moving axis are performed, and finally the position compensation of each moving axis corresponding to the next time point is achieved.

2. The multi-axis coordination method of an industrial machine tool according to claim 1, characterized in that: The magnetic field vector of each motion axis at each monitoring time point is obtained as follows: Based on the magnetic field vectors of each thermomagnetic sheet at each monitoring time point collected by the high-precision magnetic field sensor, the embedded position of each thermomagnetic sheet is corresponded to the position of each motion axis, so that the magnetic field vector of each thermomagnetic sheet at each monitoring time point is recorded as the magnetic field vector corresponding to each motion axis at each monitoring time point.

3. The multi-axis coordination method of an industrial machine tool according to claim 2, characterized in that: The receiving logic for receiving the magnetic field vector of each motion axis at each monitoring time point is: The spindle of the multi-axis machine tool is set as the Y-axis, the horizontal direction on the multi-axis machine tool workbench and the direction perpendicular to the Y-axis is set as the X-axis, and the direction perpendicular to the XY plane is set as the Z-axis. The three-dimensional coordinates of the thermal magnetic sheet in the key parts corresponding to each motion axis are collected and recorded as the three-dimensional coordinates of each thermal magnetic sheet. ; r is the serial number of each thermal magnetic sheet, r=1,2,..., R,R is the total number of thermal magnetic sheets; Collect experimental data through experimental calibration in advance, where the experimental data includes the rth thermal magnetic sheet at the reference temperature The base magnetic moment , Linear Temperature Coefficient and nonlinear temperature coefficient ; Based on the R magnetic field vectors collected by the high-precision magnetic field sensor at each monitoring time point, a thermal magnetic sheet is randomly selected from each thermal magnetic sheet as the target thermal magnetic sheet, and the R magnetic field vectors at each monitoring time point are respectively assumed to be the magnetic field vectors of the target thermal magnetic sheet at each monitoring time point; The estimated magnetic moment value corresponding to the rth magnetic field vector of the target thermal magnetic sheet at each monitoring time point is calculated from this , is the rth magnetic field vector of the target thermal magnetic sheet at the tth monitoring time point, JL is the distance between the target thermal magnetic sheet and the high-precision magnetic field sensor, , (x, y, z) is the three-dimensional coordinate of the target thermal magnetic sheet; k is the set proportional coefficient related to JL, , is the magnetic permeability in vacuum; t is the number of each monitoring time point, t=1,2,..., T,T is the total observation time of the monitoring time point, represents the norm symbol; By calculating the matching degree between the estimated magnetic moment value corresponding to the rth magnetic field vector of the target thermal magnetic sheet and the theoretical magnetic moment value corresponding to the target thermal magnetic sheet ,in is the estimated mean value of the magnetic moment of the target thermal magnetic sheet corresponding to the rth magnetic field vector, , is the theoretical magnetic moment value of the target thermal magnetic sheet at the tth monitoring time point, is the theoretical magnetic moment mean value of the target thermal magnetic sheet at all monitoring time points, ; Arrange the matching degrees in descending order, select the magnetic field vector with the highest matching degree as the magnetic field vector of the target thermal magnetic sheet corresponding to each monitoring time point, thereby obtaining the magnetic field vector of the target thermal magnetic sheet corresponding to each monitoring time point; Based on the correspondence between the embedded position of the target thermal magnetic sheet and the position of each motion axis, the magnetic field vector of the motion axis corresponding to the embedded position of the target thermal magnetic sheet at each monitoring time point is obtained; According to the analysis method, the magnetic field vector of the motion axis corresponding to the embedded position of each thermal magnetic sheet at each monitoring time point is obtained, and finally the magnetic field vector of each motion axis at each monitoring time point is obtained.

4. The multi-axis coordination method of an industrial machine tool according to claim 3, characterized in that: The calculation logic of the theoretical magnetic moment value of the target thermal magnetic sheet corresponding to each monitoring time point is: The expected temperature of the target thermal magnetic sheet at each monitoring time point is inferred by using the calibrated linear temperature coefficient α of the target thermal magnetic sheet. , The target thermal magnetic sheet is at a reference temperature The base magnetic moment under is the estimated mean value of the magnetic moment of the target thermal magnetic sheet at the tth monitoring time point, ; The theoretical magnetic moment value of the target thermal magnetic sheet corresponding to each monitoring time point is calculated accordingly. , where β is the nonlinear temperature coefficient of the target thermomagnetic sheet.

5. The multi-axis coordination method of an industrial machine tool according to claim 1, characterized in that: Calculate the thermal deformation of each motion axis at the next time point. The specific calculation formula is shown as follows: The temperature of each motion axis is displayed at each monitoring time point on the multi-axis machine tool display screen. The temperature of each motion axis at the current time point is extracted. ; i is the number of each motion axis; Based on the magnetic field vector of each motion axis at the current time point , , calculate the thermal deformation of each motion axis at the next time point ; In the above formula They represent the thermal expansion coefficient, thermal inertia coefficient and magnetic field coupling coefficient of the material corresponding to the i-th motion axis, respectively. is the thermal sensitive length of the i-th motion axis, t' is the current time point, △t is the time difference step between the current time point and the next time point, , is the temperature of each motion axis at the previous time point at the time difference step from the current time point, , is the magnetic field vector amplitude of each motion axis at the current time point.

6. The multi-axis coordination method of an industrial machine tool according to claim 1, characterized in that: Perform dynamic judgment and analysis on each motion axis, including: The thermal deformation amount of each motion axis corresponding to the next time point is compared with the preset threshold of the multi-axis machine tool. If the thermal deformation amount of a motion axis corresponding to the next time point is greater than the preset threshold of the multi-axis machine tool, the high heat mode is executed for the motion axis, otherwise the low heat mode is executed for the motion axis.

7. The multi-axis coordination method of an industrial machine tool according to claim 6, characterized in that: The process of setting the preset threshold for multi-axis machine tools is as follows: , Preset thresholds for multi-axis machines, is the set minimum sensitivity threshold, and ITGrade is the machine accuracy grade of the multi-axis machine tool.

8. The multi-axis coordination method of an industrial machine tool according to claim 6, characterized in that: The motion axis executing the high heat mode is recorded as the first compensation motion axis, and the position compensation process of each first compensation motion axis corresponding to the next time point is: By calculating the formula , calculate the position compensation amount of each first compensation motion axis corresponding to the next time point , p is the number of each first compensation motion axis, k1 is the set proportional gain value, k2 is the set differential gain value, They represent the thermal deformation of the pth first compensation motion axis at the next time point and the thermal deformation at the current time point, respectively. represents the basic compensation amount of the pth first compensation motion axis; The position compensation amount of each first compensating motion axis corresponding to the next time point is used as the denominator of the fraction, and the transmission ratio of each first compensating motion axis at the current time point is used as the numerator of the fraction. The fraction is solved to obtain the rotation arc of the motor of each first compensating motion axis corresponding to the next time point, and the corresponding rotation arc instruction is sent to the motor of each first compensating motion axis for position compensation.

9. The multi-axis coordination method of an industrial machine tool according to claim 6, characterized in that: The motion axis executing the low heat mode is recorded as the second compensation motion axis, and the position compensation process of each second compensation motion axis corresponding to the next time point is: By calculating the formula , calculate the position compensation amount of each second compensation motion axis corresponding to the next time point , q is the number of each second compensation motion axis, k3 is the set small range proportional gain, k3=0.2k1; k4 is the set integral gain, , τ is the integration time constant, g is the loop index, indicating the number of steps used for the integral summation; n is the number of integration window steps, is the qth second compensation motion axis at time The thermal deformation, They respectively represent the thermal deformation of the qth second compensatory motion axis at the next time point; The position compensation amount of each second compensating motion axis corresponding to the next time point is used as the denominator of the fraction, and the transmission ratio of each second compensating motion axis at the current time point is used as the numerator of the fraction. The fraction is solved to obtain the rotation arc of the motor of each second compensating motion axis corresponding to the next time point, and the corresponding rotation arc instruction is sent to the motor of each second compensating motion axis for position compensation.

Images