Rotation precision compensation method and system suitable for five-axis numerical control machining

Abstract

The invention relates to the technical field of numerical control machine tools, in particular to a rotation precision compensation method and system suitable for five-axis numerical control machining. According to the temperature and humidity change conditions of the environment in the operation process of the rotating shaft and the synchronization characteristics of the temperature and humidity in time when the temperature and humidity are abnormal, the temperature and humidity expansion and shrinkage abnormal degree is obtained; analyzing the position state of the rotating shaft to obtain the position deviation condition of the rotating shaft, and combining the position deviation condition with the temperature and humidity expansion and contraction abnormal degree to obtain the temperature and humidity characteristic influence degree of the rotating shaft; performing interval division on the temperature data and the humidity data, analyzing the distribution difference between the temperature and the humidity in different intervals, calculating the rotation linkage influence coefficient of the rotating shaft in combination with the temperature and humidity characteristic influence degree, and further performing rotation precision compensation on the rotating shaft. The compensation effect on the rotating precision of the rotating shaft is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of numerical control machine tools, and particularly relates to a method and system for compensating rotational accuracy applicable to five-axis numerical control machining. Background Art

[0002] Three-axis CNC machining generally refers to the machining of the linear feed axes X, Y, and Z, which is suitable for machining some disc-shaped parts and can only machine one surface at a time; four-axis CNC machining adds a rotating axis on the basis of three axes, usually rotating 360° in the horizontal plane, and is suitable for machining some box-shaped parts; five-axis CNC machining adds another rotating axis on the basis of four axes, which can complete the entire machining process at one time, with high flexibility, high precision, high integration, and complete machining capabilities, and the corresponding cost and precision are also gradually increasing. Also, due to the high-precision requirements for machining materials in fields such as aviation, considering the safety of actual applications, at present, machining parts with high-precision requirements usually choose the five-axis numerical control system corresponding to five-axis CNC for machining.

[0003] When using a five-axis numerical control system for machining parts, the two rotating axes contained therein will rotate to varying degrees according to a predetermined program. Due to the different offsets of the external temperature and humidity and the assembly positions of the internal rotating axes from the actual machining positions of the materials, it is impossible to accurately and effectively compensate according to the exact causes of the errors. Summary of the Invention

[0004] The present invention provides a method and system for compensating rotational accuracy applicable to five-axis numerical control machining to solve the existing problems.

[0005] The method and system for compensating rotational accuracy applicable to five-axis numerical control machining of the present invention adopt the following technical solutions: An embodiment of the present invention provides a method for compensating rotational accuracy applicable to five-axis numerical control machining, and the method includes the following steps: Obtain the position states of the rotating axes and environmental conditions during the operation of the five-axis machining table, where the environmental conditions include temperature data and humidity data; For any rotating axis, evaluate the environmental stability according to the temperature and humidity changes in the environment during the operation of the rotating axis, and combine the synchronous characteristics in time when the temperature and humidity are abnormal to obtain the temperature and humidity expansion and contraction abnormality degree of the any rotating axis; analyze the position deviation of the rotating axis from the position state of the rotating axis, and combine it with the temperature and humidity expansion and contraction abnormality degree to obtain the temperature and humidity characteristic influence degree of the rotating axis; Divide the temperature data and humidity data of any rotating axis during operation into intervals, analyze the distribution differences between temperature and humidity in different intervals, and combine the temperature and humidity characteristic influence degree to calculate the rotation linkage influence coefficient of the rotating axis; Using the rotation linkage influence coefficient of the rotation axis and the temperature and humidity characteristic influence degree, the error compensation coefficient of each rotation axis is obtained, so as to compensate the rotation accuracy of the rotation axis.

[0006] Furthermore, the specific method for obtaining the temperature and humidity expansion and contraction abnormality degree of any rotation axis is as follows: For any rotation axis, according to the distribution characteristics of the temperature data and humidity data of the any rotation axis within a preset time range, the environmental stability coefficient of the any rotation axis is calculated; When temperature abnormality and humidity abnormality occur during the operation of the rotation axis, obtain the corresponding abnormality duration and the time interval of the abnormality, so as to calculate the over-limit temperature and humidity synchronization degree of the rotation axis; Combining the environmental stability coefficient and the over-limit temperature and humidity synchronization degree of the any rotation axis, calculate the temperature and humidity expansion and contraction abnormality degree of the any rotation axis, and both the environmental stability coefficient and the over-limit temperature and humidity synchronization degree are positively correlated with the temperature and humidity expansion and contraction abnormality degree.

[0007] Furthermore, the specific method included in calculating the environmental stability coefficient of the any rotation axis according to the distribution characteristics of the temperature data and humidity data of the any rotation axis within a preset time range is as follows: For any rotation axis, obtain the variances of the temperature data and humidity data of the rotation axis within a preset time range, and denote them as the temperature parameter and the humidity parameter respectively; Calculate the environmental stability coefficient of the any rotation axis according to the temperature parameter and the humidity parameter, and the environmental stability coefficient is negatively correlated with both the temperature parameter and the humidity parameter.

[0008] Furthermore, the specific method included in obtaining the corresponding abnormality duration and the time interval of the abnormality when temperature abnormality and humidity abnormality occur during the operation of the rotation axis, so as to calculate the over-limit temperature and humidity synchronization degree of the rotation axis is as follows: For any rotation axis, obtain the temperature data and humidity data that continuously exceed the preset temperature range and the preset humidity range within a preset time range of the any rotation axis, and denote them as the over-limit temperature data and the over-limit humidity data respectively. Denote the number of data included in the over-limit temperature data and the over-limit humidity data as the temperature over-limit quantity and the humidity over-limit quantity respectively; obtain the minimum interval time between the over-limit temperature data and the over-limit humidity data; Calculate the over-limit temperature and humidity synchronization degree of the any rotation axis according to the temperature over-limit quantity, humidity over-limit quantity and minimum interval time of the any rotation axis.

[0009] Furthermore, the specific method included in calculating the over-limit temperature and humidity synchronization degree of the any rotation axis according to the temperature over-limit quantity, humidity over-limit quantity and minimum interval time of the any rotation axis is as follows: The specific calculation method of the over-temperature and over-humidity synchronization degree is as follows: Wherein, is the over-temperature and over-humidity synchronization degree of the th rotating shaft; is the th over-temperature limit of the th rotating shaft, is the th over-humidity limit of the th rotating shaft, is the quantity of over-temperature limits of the th rotating shaft, is the quantity of over-humidity limits of the th rotating shaft, is the minimum interval time between the over-temperature data and over-humidity data of the th rotating shaft, is the absolute value function, is the minimum value function.

[0010] Furthermore, the method for analyzing the position state of the rotating shaft to obtain the position deviation of the rotating shaft and combining it with the temperature and humidity expansion and contraction abnormality degree to obtain the temperature and humidity characteristic influence degree of the rotating shaft includes the following specific methods: Install a laser sensor on each of the two rotating shafts on the five-axis processing table, and preset a number of laser stop points on the plane where each rotating shaft rotates alone. Record the number of times the laser irradiates on the laser stop points and the corresponding moments within the preset time range for each rotating shaft, and denote them as the stop times and stop moments respectively. Based on the stop moments, construct a laser stop moment sequence of the corresponding rotating shaft at each laser stop point; For any rotating shaft, calculate the absolute value of the difference between the stop times corresponding to the laser stop points of the any rotating shaft, and denote it as the stop time difference between the laser stop points of the any rotating shaft; calculate the variance of all elements in the forward difference sequence of the laser stop moment sequence corresponding to any laser stop point of the any rotating shaft, and denote it as the offset parameter of the any laser stop point; obtain the absolute value of the difference between the offset parameters of different laser stop points of any rotating shaft, and denote it as the offset value between the laser stop points of the any rotating shaft; According to the stop time difference and offset value of any rotating shaft, calculate the error deviation degree of the any rotating shaft. Both the stop time difference and the offset value are positively correlated with the error deviation degree. The error deviation degree of the rotating shaft is used to describe the position deviation of the rotating shaft; Calculate the temperature and humidity characteristic influence degree of any rotating axis according to the temperature and humidity expansion and contraction abnormality degree and error deviation degree of the any rotating axis. Both the temperature and humidity expansion and contraction abnormality degree and the error deviation degree are positively correlated with the temperature and humidity characteristic influence degree.

[0011] Further, the method for partitioning the temperature data and humidity data of any rotating axis during operation includes the following specific steps: Use the normalized value of the temperature and humidity characteristic influence degree as the weight of the intermediate value of the preset temperature range and preset humidity range. Take the result obtained by weighted multiplication as the clustering center, and use the K-means clustering algorithm to cluster the temperature data and humidity data of any rotating axis within the preset time range respectively, to obtain several clustering clusters included in the temperature data and humidity data respectively; Denote the clustering clusters with the largest number of data points in the temperature data and humidity data respectively as the local temperature range clustering cluster and the local humidity range clustering cluster. Obtain the interval formed by the minimum temperature value and the maximum temperature value in all clustering clusters of the temperature data, and denote it as the temperature interval of the corresponding clustering cluster. Denote the temperature interval of the local temperature range clustering cluster as the temperature main influence interval of the corresponding rotating axis, and denote the temperature intervals of the remaining clustering clusters that do not overlap with the temperature main influence interval as the temperature weak influence intervals of the corresponding rotating axis; By analogy, obtain the humidity main influence interval and humidity weak influence interval of any rotating axis.

[0012] Further, the method for analyzing the distribution difference between temperature and humidity in different intervals and calculating the rotation linkage influence coefficient of the rotating axis by combining the temperature and humidity characteristic influence degree includes the following specific steps: Obtain the temperature and humidity independent characteristic values of the rotating axis; Calculate the variance of the temperature data of each rotating axis in the corresponding temperature main influence interval, and denote it as the local temperature variance; Calculate the variance of the humidity data of each rotating axis in the humidity main influence interval, and denote it as the local humidity variance. The specific calculation method of the rotation linkage influence coefficient is: Where, is the rotation linkage influence coefficient of the th rotating axis; is the temperature and humidity characteristic influence degree of the th rotating axis, is the th temperature and humidity independent characteristic value of the rotating axis, is the th local temperature variance of the rotating axis, is the th local humidity variance of the rotating axis, is the absolute value function, is a preset first hyperparameter, is a preset second hyperparameter.

[0013] Furthermore, the specific method for the temperature-humidity independent eigenvalue includes: Preset the temperature-humidity independent eigenvalue Y. If the overlap degree between the main influence intervals of temperature and humidity between different rotation axes is less than , merge the corresponding main influence intervals of temperature and humidity, and assign the temperature-humidity independent eigenvalue of each rotation axis to be ; otherwise, assign it to be , where , and , and are all preset parameters.

[0014] A rotation accuracy compensation system applicable to five-axis numerical control machining includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the rotation accuracy compensation method applicable to five-axis numerical control machining.

[0015] The beneficial effects of the technical solution of the present invention are as follows: The embodiments of the present invention consider the influence of temperature and humidity changes on the rotation axis. By analyzing the temperature-humidity expansion and contraction abnormality degree of the rotation axis and combining the position deviation situation of the rotation axis, it can more accurately evaluate the influence of environmental factors on the rotation accuracy in five-axis numerical control machining, and adjust the error of the rotation axis in real time according to different environmental conditions. It can perform dynamic compensation according to the real-time environmental conditions, that is, by adopting the method of real-time obtaining temperature and humidity data and combining the operating state of the rotation axis, it has the ability of dynamic adjustment, which helps to timely respond to the influence brought by environmental changes and avoid machining accuracy problems caused by environmental factor fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 is a flowchart of the steps of the rotation accuracy compensation method applicable to five-axis numerical control machining of the present invention; Figure 2 is a three-dimensional model schematic diagram of a five-axis machining table; Figure 3 is an assembly schematic diagram of a laser sensor. Detailed implementation manners

[0018] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, elaborate in detail on the specific implementation manners, structures, features, and effects of the rotation accuracy compensation method and system applicable to five-axis numerical control machining proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0020] The following will specifically describe the specific solutions of the rotation accuracy compensation method and system applicable to five-axis numerical control machining provided by the present invention in conjunction with the accompanying drawings.

[0021] Please refer to Figure 1 , which shows a flowchart of the steps of the rotation accuracy compensation method applicable to five-axis numerical control machining provided by an embodiment of the present invention. The method includes the following steps: Step S001: Obtain the position state of the rotating axes and environmental conditions of the five-axis machining table during operation.

[0022] It should be noted that the five-axis machining table is a numerically controlled machine tool that can perform machining simultaneously in five different axial directions. Compared with traditional three-axis machining machine tools, the five-axis machining table has higher machining accuracy and the ability to machine complex shapes. Specifically, by combining three linear axes (X, Y, Z axes) and two rotating axes (A axis and B axis), the cutting tool can move more flexibly in space, thereby realizing more complex workpiece machining, such as Figure 2 shown is a three-dimensional model schematic diagram of the five-axis machining table.

[0023] Specifically, in order to implement the rotation accuracy compensation method applicable to five-axis numerical control machining proposed in this embodiment, it is first necessary to obtain the position state of the rotating axes and environmental conditions of the five-axis machining table during operation. The specific process is as follows: First, install a laser sensor on each of the two rotating axes of the five-axis machining table, and preset laser stay points on the plane where each rotating axis rotates alone. Record the number of times the laser irradiates on the laser stay points and the corresponding moments within a preset time range for each rotating axis, and denote them as the stay times and stay moments respectively. Based on the stay moments, construct a laser stay moment sequence for the corresponding rotating axis at each laser stay point. As Figure 3 shown is an assembly schematic diagram of the laser sensor.

[0024] It should be noted that in the embodiments of the present invention, the preset time range is 5 minutes according to experience, and the preset time range can be adjusted according to actual situations. The embodiments of the present invention do not make specific limitations.

[0025] Then, install temperature sensors and humidity sensors in the machining workshop where the five-axis machining table is located to obtain temperature data and humidity data.

[0026] Finally, make each rotating shaft rotate individually at a rotational speed of 20 rpm (revolutions per minute) for 5 minutes.

[0027] Thus far, through the above method, a laser residence time sequence reflecting the position state of the rotating shaft and environmental data reflecting environmental conditions, namely temperature data and humidity data, are obtained.

[0028] Step S002: For any rotating shaft, evaluate the environmental stability based on the temperature and humidity changes in the environment during the operation of the rotating shaft, and combine the synchronous characteristics in time when the temperature and humidity are abnormal to obtain the temperature and humidity expansion and contraction abnormality degree of the any rotating shaft; analyze the position state of the rotating shaft to obtain the position deviation of the rotating shaft, and combine it with the temperature and humidity expansion and contraction abnormality degree to obtain the temperature and humidity characteristic influence degree of the rotating shaft.

[0029] It should be noted that when using a five-axis numerical control system for part machining, due to the high-precision requirements of the parts, the surface of the rotating shaft that changes slightly due to the external temperature and humidity will cause a large range of errors during the rotation of the rotating shaft. And usually, the two rotating shafts in the five-axis machining table usually rotate simultaneously along their respective rotation directions. The motion states of the two rotating shafts during simultaneous rotation are different from those during the rotation of a single rotating shaft, so the influence on the change of the machining position will also be different; therefore, the embodiments of the present invention choose to analyze the expandable and contractible state of the rotating shaft due to the temperature and humidity changes in the machining environment, and combine the influence on the corresponding machining position during the rotation between different rotating shafts to obtain the error compensation coefficient of each rotating shaft for compensating the rotation angle of the rotating shaft during the machining process, thereby improving the rotation accuracy.

[0030] Specifically, in step S201, for any rotating shaft, according to the distribution characteristics of the temperature data and humidity data of the any rotating shaft within the preset time range, calculate the environmental stability coefficient of the any rotating shaft, obtain the corresponding abnormal duration and abnormal time interval when the temperature and humidity are abnormal during the operation of the rotating shaft, thereby calculate the over-limit temperature and humidity synchronization degree of the rotating shaft, and combine the environmental stability coefficient and over-limit temperature and humidity synchronization degree of the any rotating shaft to calculate the temperature and humidity expansion and contraction abnormality degree of the any rotating shaft.

[0031] It should be noted that, under normal circumstances, when machining parts using a five-axis numerical control system, the temperature and humidity in the workshop are dynamically regulated within a certain range of variation; within this range of variation, as the machining process progresses, the more stable the changes in the corresponding data, the smaller the degree of variation in the surface of the rotating shaft due to thermal expansion and contraction caused by external factors, and the lower the probability of the rotating shaft being displaced due to thermal expansion and contraction, resulting in a large error in the rotational accuracy.

[0032] Step S201.1: For any rotating shaft, calculate the environmental stability coefficient of the any rotating shaft according to the distribution characteristics of the temperature data and humidity data of the any rotating shaft within a preset time range.

[0033] First, for any rotating shaft, obtain the variances of the temperature data and humidity data of the rotating shaft within a preset time range, and denote them as the temperature parameter and the humidity parameter respectively.

[0034] Then, calculate the environmental stability coefficient of the any rotating shaft according to the temperature parameter and the humidity parameter, and the environmental stability coefficient is negatively correlated with both the temperature parameter and the humidity parameter.

[0035] As an embodiment, the specific calculation method of the environmental stability coefficient is: Wherein, is the environmental stability coefficient of the th rotating shaft; is the temperature parameter of the th rotating shaft, is the humidity parameter of the th rotating shaft, is the exponential function with the natural constant as the base.

[0036] It should be noted that the environmental stability coefficient of the rotating shaft is used to describe the stability of the environmental conditions during the operation of the rotating shaft. When the temperature and humidity change greatly during the operation, the corresponding environmental conditions are unstable, then the values of the corresponding temperature parameter and humidity parameter will be large, and the environmental stability coefficient will be small.

[0037] Step S201.2: When temperature anomalies and humidity anomalies occur during the operation of the rotating shaft, obtain the corresponding abnormal duration and the time interval of the anomalies, so as to calculate the over-limit temperature and humidity synchronization degree of the rotating shaft.

[0038] It should be noted that in the machining workshop environment of five-axis numerical control, when the abnormal changes of the rotating axis are mainly caused by external factors, for the temperature and humidity in the external environment, there is usually a time period of relatively synchronous abnormal changes, so as to ensure that under the influence of external factors, the rotation accuracy of the rotating axis has a large error change as much as possible.

[0039] First, for any rotating axis, obtain the temperature data and humidity data of the any rotating axis that continuously exceed the preset temperature range and the preset humidity range within a preset time range, and record them as over-limit temperature data and over-limit humidity data respectively. Record the number of data included in the over-limit temperature data and the over-limit humidity data as the temperature over-limit quantity and the humidity over-limit quantity respectively; obtain the minimum interval time between the over-limit temperature data and the over-limit humidity data.

[0040] It should be noted that since the temperature data and the humidity data are time-series data with continuous fluctuating changes, when the temperature and humidity change, there may be multiple situations of continuously exceeding the preset range (i.e., the preset temperature range and the preset humidity range). Therefore, when obtaining the temperature over-limit quantity and the humidity over-limit quantity, there may be multiple temperature over-limit quantities and humidity over-limit quantities in the temperature data and the humidity data.

[0041] It should be noted that generally, the temperature of the normal working environment of the rotating axis is within the range, and the humidity of the normal working environment is within the range. Therefore, in the embodiment of the present invention, the preset temperature range is and the humidity range is , which can be specifically adjusted according to the requirements in the actual production and processing process, and the embodiment of the present invention does not make specific limitations.

[0042] Then, calculate the over-limit temperature and humidity synchronization degree of the any rotating axis according to the temperature over-limit quantity, humidity over-limit quantity and minimum interval time of the any rotating axis.

[0043] As an embodiment, the specific calculation method of the over-limit temperature and humidity synchronization degree is: Among them, is the over-limit temperature and humidity synchronization degree of the th rotating axis; is the th temperature over-limit quantity of the th rotating axis, is the th humidity over-limit quantity of the th rotating axis, is the quantity of the temperature over-limit quantity of the th rotating axis, is the The number of humidity over-limit values of a rotating shaft, is the minimum interval time between the over-limit temperature data and the over-limit humidity data of the th rotating shaft, is the absolute value function,

[0044] It should be noted that the more synchronized the temperature and humidity data beyond the limit range are, the more obvious the influence of the corresponding external factors of temperature and humidity on the rotating shaft is.

[0045] Step S201.3: For any rotating shaft, combine the environmental stability coefficient and the over-limit temperature and humidity synchronization degree of the any rotating shaft to calculate the temperature and humidity expansion and contraction abnormality degree of the any rotating shaft.

[0046] It should be noted that the more unstable the temperature and humidity in the processing environment are, and the more obvious the influence of the external temperature and humidity on the rotating shaft is, it indicates that the change of temperature and humidity in the processing environment is more obvious in the morphological change of thermal expansion and contraction of the rotating shaft, and it reflects that the change of temperature and humidity in the processing environment is more likely to cause a relatively large surface expansion and contraction of the rotating shaft.

[0047] As an embodiment, the specific calculation method of the temperature and humidity expansion and contraction abnormality degree is: Wherein, is the temperature and humidity expansion and contraction abnormality degree of the th rotating shaft; is the environmental stability coefficient of the th rotating shaft, is the over-limit temperature and humidity synchronization degree of the

[0048] Step S202: Analyze the position state of the rotating shaft to obtain the position deviation of the rotating shaft, and combine it with the temperature and humidity expansion and contraction abnormality degree to obtain the temperature and humidity characteristic influence degree of the rotating shaft.

[0049] It should be noted that when the rotating shaft undergoes volume change due to the physical property of thermal expansion and contraction, the laser sensor installed on the rotating shaft will also cause the laser position after rotation to shift due to the volume change of the rotating shaft, thereby changing the distribution state between the laser rain laser stop points irradiated on the plane at the corresponding moment.

[0050] It should be noted that under normal circumstances, since the rotation speed and sampling frequency are fixed, the irradiation of a rotating shaft on two corresponding laser staying points is the same. However, due to the continuous influence of different external temperature and humidity on the expansion and contraction degree of the rotating shaft, there will be a certain difference in the number of times the laser irradiates on the two corresponding laser staying points. Therefore, in the embodiments of the present invention, by analyzing the position information of the laser staying points, the error deviation degree of the rotating shaft is obtained to describe the position deviation situation of the rotating shaft.

[0051] First, for any rotating shaft, calculate the absolute value of the difference between the corresponding staying times of the laser staying points of the any rotating shaft, denoted as the staying time difference between the laser staying points of the any rotating shaft; calculate the variance of all elements in the forward difference sequence of the laser staying time sequence corresponding to any laser staying point of the any rotating shaft, denoted as the offset parameter of the any laser staying point; obtain the absolute value of the difference between the offset parameters of different laser staying points of any rotating shaft, denoted as the offset value between the laser staying points of the any rotating shaft.

[0052] Then, according to the staying time difference and the offset value of any rotating shaft, calculate the error deviation degree of the any rotating shaft, and both the staying time difference and the offset value are positively correlated with the error deviation degree.

[0053] As an embodiment, the specific calculation method of the error deviation degree is: Wherein, is the error deviation degree of the th rotating shaft, represents the number of laser staying points corresponding to the th rotating shaft, is the th and th staying time difference between the th laser staying points of the th rotating shaft, is the th and th offset value between the th laser staying points of the

[0054] It should be noted that if the influence of external temperature and humidity factors on the rotating shaft is greater, the actual rotation error of the rotating shaft is greater, indicating that the rotation error generated by the rotating shaft is more likely to be mainly affected by external temperature and humidity, reflecting that it is more necessary to consider the compensation of rotation accuracy according to the corresponding temperature and humidity factors.

[0055] Finally, according to the temperature and humidity expansion and contraction abnormality degree and error deviation degree of any rotation axis, calculate the temperature and humidity characteristic influence degree of the any rotation axis, and both the temperature and humidity expansion and contraction abnormality degree and the error deviation degree are positively correlated with the temperature and humidity characteristic influence degree.

[0056] As an embodiment, the specific calculation method of the temperature and humidity characteristic influence degree is as follows: Among them, is the temperature and humidity characteristic influence degree of the th rotation axis; is the temperature and humidity expansion and contraction abnormality degree of the th rotation axis, and is the error deviation degree of the th rotation axis.

[0057] So far, according to the temperature and humidity changes in the processing environment, analyze the expandable and contractible state of the rotation axis, and divide several error temperature and humidity intervals.

[0058] Step S003: Divide the temperature data and humidity data of any rotation axis during operation into intervals, analyze the distribution differences between temperature and humidity in different intervals, and combine the temperature and humidity characteristic influence degree to calculate the rotation linkage influence coefficient of the rotation axis.

[0059] Specifically, in step S301, divide the temperature data and humidity data into intervals through the temperature and humidity characteristic influence degree, and divide the main temperature influence interval, weak temperature influence interval, main humidity influence interval and weak humidity influence interval.

[0060] As an embodiment, the obtaining methods of the main temperature influence interval, weak temperature influence interval, main humidity influence interval and weak humidity influence interval include: First, use the normalized value of the temperature and humidity characteristic influence degree as the weight of the intermediate value of the preset temperature range and preset humidity range, use the weighted product result as the clustering center, and use the K-means clustering algorithm to cluster the temperature data and humidity data of any rotation axis within the preset time range respectively, to obtain several clustering clusters included in the temperature data and humidity data respectively; respectively record the clustering clusters with the largest number of data points in the temperature data and humidity data as the local temperature range clustering cluster and local humidity range clustering cluster.

[0061] It should be noted that according to experience, the K value in the K-means clustering algorithm is preset to 3, which can be adjusted according to the actual situation, and the embodiments of the present invention do not make specific limitations.

[0062] Then, obtain the interval formed by the minimum temperature value and the maximum temperature value in all clusters under the temperature data, which is denoted as the temperature interval of the corresponding cluster. Denote the temperature interval of the local temperature range cluster as the main temperature influence interval of the corresponding rotating shaft, and denote the temperature interval in the remaining clusters that does not overlap with the main temperature influence interval as the weak temperature influence interval of the corresponding rotating shaft; and so on, obtain the main humidity influence interval and the weak humidity influence interval of any rotating shaft.

[0063] It should be noted that, usually, since the two rotating shafts are of the same model, the corresponding material size requirements are basically the same, and the corresponding interval ranges mainly affected by temperature and humidity in the environment are also basically the same.

[0064] In addition, preset the temperature and humidity independent eigenvalue Y. If the overlap degree between the main temperature and humidity influence intervals of different rotating shafts is less than , merge the corresponding main temperature and humidity influence intervals, and assign the temperature and humidity independent eigenvalue of each rotating shaft to ; otherwise, assign them all to , where , and , and are all preset parameters.

[0065] It should be noted that, according to experience, the preset parameters , and are 90%, 1, and 0.2 respectively, and their values can be adjusted according to specific situations. The embodiments of the present invention do not make specific limitations.

[0066] Step S302, calculate the rotational linkage influence coefficient of the th rotating shaft within the main temperature and humidity influence interval.

[0067] It should be noted that if the degrees of influence of different rotating shafts by temperature and humidity are similar, the more similar the thermal expansion and contraction states of the corresponding shaft bodies are, it indicates that when different rotating shafts perform combined rotation (that is, both rotating shafts start to rotate, not just one rotating shaft rotates alone), there is synchrony in the influence of the rotating shafts on the vibration of the overall rotation activity, and it reflects that the deviation generated by the overall rotation is more likely to fluctuate. In addition, if the degrees of influence of different rotating shafts by temperature and humidity are not similar, it indicates that the rotating shaft is more likely to have a limited space for telescopic change due to improper assembly of the rotating shaft. When different rotating shafts perform combined rotation, the synchrony of the influence of the rotating shafts on the vibration of the overall rotation activity is worse, and it reflects that the deviation generated by the overall rotation is relatively more stable.

[0068] As an embodiment, the method for obtaining the rotational linkage influence coefficient of any rotating shaft includes: First, calculate the variance of the temperature data of each rotation axis in the corresponding main influence interval of temperature, denoted as the local temperature variance; calculate the variance of the humidity data of each rotation axis in the main influence interval of humidity, denoted as the local humidity variance.

[0069] Then, according to the temperature and humidity characteristic influence degrees, temperature and humidity independent eigenvalues, local temperature variances, and local humidity variances of different rotation axes, calculate the rotation linkage influence coefficients of any rotation axis in the main influence interval of temperature and the main influence interval of humidity respectively.

[0070] As an embodiment, the specific calculation method of the rotation linkage influence coefficient is as follows: Wherein, is the rotation linkage influence coefficient of the th rotation axis; is the temperature and humidity characteristic influence degree of the th rotation axis, is the temperature and humidity independent eigenvalue of the th rotation axis, is the local temperature variance of the th rotation axis, is the local humidity variance of the th rotation axis, is the absolute value function, is the preset first hyperparameter, is the preset second hyperparameter.

[0071] It should be noted that according to experience, the first hyperparameter is preset to 0.1 to avoid the situation where the denominator is 0, and the second hyperparameter is preset to 0.6. The first hyperparameter and the second hyperparameter can be adjusted according to the actual situation, and the embodiments of the present invention do not make specific limitations.

[0072] And so on, obtain the rotation linkage influence coefficients of the rotation axes in each weak influence interval of temperature and humidity.

[0073] So far, analyze the combined influence of the position offsets between the rotation axes when multiple rotation axes perform linkage rotation in different error temperature and humidity intervals, and obtain the rotation linkage influence coefficients of each rotation axis in the same error temperature and humidity interval.

[0074] Step S004: Use the rotation linkage influence coefficients and temperature and humidity characteristic influence degrees of the rotation axes to obtain the error compensation coefficients of each rotation axis, so as to perform rotation accuracy compensation on the rotation axes.

[0075] It should be noted that during the operation of the five-axis machining table, when the rotation angle of the rotating axis has an error due to the influence of different factors, it is necessary to obtain compensation values according to the influence of the corresponding factors on the rotating axis and compensate the rotation angle to improve the rotation accuracy of the rotating axis. Specifically, the magnitude of the rotational coupling influence coefficient of the rotating axis reflects the cause of the corresponding error when the rotation accuracy of the rotating axis is insufficient. When the rotational coupling influence coefficient is too large, it is usually affected by external environmental conditions, that is, the rotation accuracy of the rotating axis has an error dominated by external temperature and humidity. When the rotational coupling influence coefficient is too small, it is usually due to problems with the assembly position of the internal rotating axis, resulting in errors in the rotation accuracy. In other cases, it is the combined influence of external temperature and humidity conditions and the assembly position of the rotating axis that leads to insufficient rotation accuracy. Therefore, in the embodiments of the present invention, based on the magnitude of the rotational coupling influence coefficient of the rotating axis, the error compensation coefficients in different cases are obtained through the temperature and humidity characteristic influence degree of the rotating axis, the rotational coupling influence coefficient, and the temperature and humidity independent characteristic value respectively.

[0076] Specifically, as an embodiment, for any rotating axis, the specific method for obtaining the error compensation coefficient of the any rotating axis is as follows: Wherein, is the error compensation coefficient of the rotating axis, is the temperature and humidity characteristic influence degree of the rotating axis, is the rotational coupling influence coefficient of the rotating axis, is the temperature and humidity independent characteristic value of the rotating axis, is the normalization function.

[0077] Through the above steps, the compensation process for the rotation accuracy of the rotating axis of the five-axis machining table is completed.

[0078] An embodiment of the present invention also provides a rotation accuracy compensation system applicable to five-axis numerical control machining. The system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the rotation accuracy compensation method applicable to five-axis numerical control machining are implemented.

[0079] The embodiments of the present invention consider the influence of temperature and humidity changes on the rotating shaft. By analyzing the temperature and humidity expansion and contraction abnormality degree of the rotating shaft and combining the deviation situation of the rotating shaft position, it can more accurately evaluate the influence of environmental factors on the rotation accuracy in five-axis CNC machining, and adjust the error of the rotating shaft in real time according to different environmental conditions, and can perform dynamic compensation according to the real-time environmental conditions, that is, by the method of obtaining temperature and humidity data in real time and combining the operating state of the rotating shaft, which has the ability of dynamic adjustment, helps to timely respond to the influence brought by environmental changes, and avoids the machining accuracy problems caused by the fluctuations of environmental factors.

[0080] It should be noted that the model used in this embodiment is only used to represent the negative correlation relationship and restrict the result of the model output to be within the interval. In specific implementation, it can be replaced with other models with the same purpose. This embodiment only takes the model as an example for description and does not make specific limitations on it, where refers to the input of this model.

[0081] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rotation accuracy compensation method suitable for five-axis CNC machining, characterized in that: The method comprises the following steps: Acquire the position state of the rotating axis and the environmental conditions of the five-axis machining table during operation, wherein the environmental conditions include temperature data and humidity data; For any rotating shaft, the environmental stability is evaluated by the changes in the temperature and humidity of the environment during the operation of the rotating shaft, and the temperature and humidity expansion and contraction abnormality of the arbitrary rotating shaft is obtained by combining the synchronization characteristics in time when the temperature and humidity are abnormal; the position deviation of the rotating shaft is obtained by analyzing the position state of the rotating shaft, and combined with the temperature and humidity expansion and contraction abnormality, the temperature and humidity characteristic influence of the rotating shaft is obtained; Divide the temperature and humidity data of any rotating axis during operation into intervals, analyze the distribution differences between temperature and humidity in different intervals, and calculate the rotation linkage influence coefficient of the rotating axis by combining the influence of temperature and humidity characteristics; The error compensation coefficient of each rotating axis is obtained by utilizing the rotation linkage influence coefficient of the rotating axis and the influence degree of the temperature and humidity characteristics, so as to compensate the rotation accuracy of the rotating axis.

2. The rotation accuracy compensation method suitable for five-axis CNC machining according to claim 1, characterized in that: The specific method for obtaining the temperature and humidity expansion and contraction anomaly of any rotating axis is as follows: For any rotating axis, calculating the environmental stability coefficient of the arbitrary rotating axis according to the distribution characteristics of the temperature data and the humidity data of the arbitrary rotating axis within a preset time range; When the rotating shaft has abnormal temperature and humidity during operation, the corresponding abnormal duration and abnormal time interval are obtained, so as to calculate the over-limit temperature and humidity synchronization degree of the rotating shaft; The temperature and humidity expansion and contraction anomaly of the arbitrary rotating axis is calculated by combining the environmental stability coefficient and the over-limit temperature and humidity synchronization of the arbitrary rotating axis. The environmental stability coefficient and the over-limit temperature and humidity synchronization are both positively correlated with the temperature and humidity expansion and contraction anomaly.

3. The rotation accuracy compensation method for five-axis CNC machining according to claim 2, characterized in that: The specific method of calculating the environmental stability coefficient of the arbitrary rotating axis according to the distribution characteristics of the temperature data and the humidity data of the arbitrary rotating axis within a preset time range includes: For any rotating axis, obtain the variance of the temperature data and the variance of the humidity data of the rotating axis within a preset time range, and record them as temperature parameters and humidity parameters respectively; The environmental stability coefficient of the arbitrary rotating axis is calculated according to the temperature parameter and the humidity parameter, and the environmental stability coefficient is negatively correlated with both the temperature parameter and the humidity parameter.

4. The rotation accuracy compensation method for five-axis CNC machining according to claim 2, characterized in that: The method of obtaining the abnormal temperature and humidity during the operation of the rotating shaft, the corresponding abnormal duration and the abnormal time interval, so as to calculate the over-limit temperature and humidity synchronization degree of the rotating shaft, includes the following specific methods: For any rotating shaft, obtain the temperature data and humidity data of the any rotating shaft that continuously exceed the preset temperature range and the preset humidity range within the preset time range, record them as over-limit temperature data and over-limit humidity data, respectively, record the number of data contained in the over-limit temperature data and the over-limit humidity data as the temperature over-limit amount and the humidity over-limit amount, respectively; obtain the minimum interval time between the over-limit temperature data and the over-limit humidity data; The over-limit temperature and humidity synchronization degree of any rotating axis is calculated according to the over-limit temperature, over-limit humidity and minimum interval time of any rotating axis.

5. The rotation accuracy compensation method for five-axis CNC machining according to claim 4, characterized in that: The method of calculating the over-limit temperature and humidity synchronization degree of any rotating axis according to the over-limit temperature, over-limit humidity and minimum interval time of any rotating axis includes: The specific calculation method of the over-limit temperature and humidity synchronization degree is: in, For the Excessive temperature and humidity synchronization of the rotating axes; For the The first axis of rotation The temperature exceeds the limit. For the The first axis of rotation Humidity exceeds limit. For the The number of rotation axis temperature violations, For the The number of rotation axis humidity exceeding the limit, For the The minimum interval time between the over-limit temperature data and the over-limit humidity data of each rotating axis, is the absolute value function, is the minimum function.

6. The rotation accuracy compensation method for five-axis CNC machining according to claim 1, characterized in that: The position state of the rotating shaft is analyzed to obtain the position deviation of the rotating shaft, and combined with the temperature and humidity expansion and contraction abnormality to obtain the temperature and humidity characteristic influence of the rotating shaft, including the specific method of: A laser sensor is installed on each of the two rotating axes on the five-axis machining table, and a number of laser stop points are preset on the plane corresponding to each rotating axis when it rotates independently. The number of times the laser irradiates the laser stop point and the corresponding time of each rotating axis within a preset time range are recorded, which are recorded as the number of stops and the stop time, respectively. Based on the stop time, a laser stop time sequence of the corresponding rotating axis at each laser stop point is constructed; For any rotation axis, calculate the absolute value of the difference between the corresponding stop times of the laser stop points of the arbitrary rotation axis, and record it as the difference in the stop times between the laser stop points of the arbitrary rotation axis; calculate the variance of all elements in the forward difference sequence of the laser stop time sequence corresponding to any laser stop point of the arbitrary rotation axis, and record it as the offset parameter of the arbitrary laser stop point; obtain the absolute value of the difference between the offset parameters of different laser stop points of the arbitrary rotation axis, and record it as the offset value between the laser stop points of the arbitrary rotation axis; Calculating the error deviation of any rotating axis according to the difference in the number of stops and the offset value of any rotating axis, wherein the difference in the number of stops and the offset value are both positively correlated with the error deviation, and the error deviation of the rotating axis is used to describe the position deviation of the rotating axis; The temperature and humidity characteristic influence of any rotating axis is calculated according to the temperature and humidity expansion and contraction abnormality and the error deviation of any rotating axis. Both the temperature and humidity expansion and contraction abnormality and the error deviation are positively correlated with the temperature and humidity characteristic influence.

7. The rotation accuracy compensation method suitable for five-axis CNC machining according to claim 1, characterized in that: The specific method of dividing the temperature data and humidity data of any rotating shaft during operation into intervals includes: The normalized value of the temperature and humidity feature influence is used as the weight of the middle value of the preset temperature range and the preset humidity range, and the result obtained after the weighted product is used as the cluster center. The temperature data and humidity data of any rotation axis within the preset time range are clustered using the K-means clustering algorithm to obtain several clusters contained in the temperature data and humidity data respectively; the clusters with the largest number of data points in the temperature data and humidity data are recorded as the local temperature range cluster and the local humidity range cluster respectively; The interval formed by the minimum temperature value and the maximum temperature value in all clusters under the temperature data is obtained, and recorded as the temperature interval of the corresponding cluster. The temperature interval of the local temperature range cluster is recorded as the temperature main influence interval of the corresponding rotation axis. The temperature interval in the remaining clusters that does not overlap with the temperature main influence interval is recorded as the temperature weak influence interval of the corresponding rotation axis. By analogy, the humidity main influence interval and humidity weak influence interval of any rotation axis are obtained.

8. The rotation accuracy compensation method for five-axis CNC machining according to claim 7, characterized in that: The analysis of the distribution difference between temperature and humidity in different intervals and the calculation of the rotation linkage influence coefficient of the rotating axis in combination with the temperature and humidity characteristic influence include the following specific methods: Obtain the temperature and humidity independent characteristic values ​​of the rotating axis; Calculate the variance of the temperature data of each rotation axis in the corresponding temperature main influence interval, which is recorded as the local temperature variance; calculate the variance of the humidity data of each rotation axis in the humidity main influence interval, which is recorded as the local humidity variance; The specific calculation method of the rotation linkage influence coefficient is: in, For the The rotation linkage influence coefficient of each rotation axis; For the The influence of temperature and humidity characteristics of the rotating axis, For the The temperature and humidity independent characteristic values ​​of the rotation axis, For the The local temperature variance of the rotating axis, For the The local humidity variance about the rotation axis, is the absolute value function, is the first preset hyperparameter, is the second preset hyperparameter.

9. The rotation accuracy compensation method suitable for five-axis CNC machining according to claim 8, characterized in that: The temperature and humidity independent characteristic value includes the following specific methods: Preset temperature and humidity independent characteristic value Y, if the overlap between the main influence intervals of temperature and humidity between different rotation axes is less than , merge the corresponding temperature and humidity main influence intervals, and convert the temperature and humidity independent characteristic values ​​of each rotation axis The average value is ; Otherwise, the value is ,in ,and , and These are preset parameters.

10. A rotation accuracy compensation system for five-axis CNC machining, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the rotation accuracy compensation method applicable to five-axis CNC machining as described in any one of claims 1 to 9 are implemented.

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