Complex component milling stability monitoring device, method and system and medium

Abstract

The invention relates to the field of machining, and discloses a complex component milling stability monitoring device, method and system and a medium, the complex component milling stability monitoring device comprises a rotor module, an iron core of the rotor module is installed on the outer side of a hollow rotating shaft, an induction coil is wound on the outer side of the iron core in the same direction, and a magnetic ring is arranged on the outer side of the iron core; the hollow rotating shaft is fixed with the handle; the permanent magnet of the stator module is fixed on the inner side of the shell; the rotor module is positioned on the inner side of the permanent magnet; the end face of the shell is provided with a sensor installation groove, the outer side of the shell is provided with a charging interface, and the shell is provided with an installation support fixing hole and a front / rear end cover fixing hole which are used for installation. The rotor module is arranged on the inner side of the stator module, a shell of the stator module is fixed to the sealing module, and the data acquisition and transmission module is connected with the sealing module to form the complex component milling stability monitoring device. A fixing module is installed on a stator module shell and connected with a main shaft system shell, and a rotor module is fixed to a cutter handle through a bolt.

Description

Technical Field

[0001] The present invention relates to the field of mechanical processing technology, and in particular to a complex component milling processing stability monitoring device, method, system and medium used in the field of milling processing stability monitoring. Background Art

[0002] Complex components such as large cabins and integral impellers in the fields of aviation and aerospace are typical complex components with complex topological structures, high prices, high requirements for surface quality and dimensional accuracy. Milling is the main method for processing and manufacturing such components. The milling process has long tool overhang, high material removal rate, and large cutting force. At the same time, the components have weak rigidity, and chatter is very easy to occur during the milling process. Chatter is a typical self-excited vibration that will accelerate tool wear, reduce workpiece surface quality and machining accuracy. Especially in the finishing stage, severe chatter will cause the entire workpiece to be scrapped, causing huge economic losses to the company. Severe chatter even directly affects the rotation accuracy of the spindle system. The reduction in spindle rotation accuracy further aggravates the degree of degradation of the milling process. Collecting the vibration signal of the milling process to monitor the milling state in real time online, and then adjusting the milling state according to the detection results is an effective way to avoid milling chatter and ensure machining quality.

[0003] However, the existing vibration sensors on the market are mainly powered by data cables and transmit the collected information to the computer. The redundant data cables not only increase the wiring workload at the processing site, but also due to the constraints of the data cables, the sensor cannot rotate with the spindle, making it difficult to collect information such as the spindle's rotation accuracy under actual processing conditions. Existing wireless sensors require built-in batteries and signal generators, and are large in size, so they cannot be used to collect spindle rotation accuracy and vibration information during milling.

[0004] Therefore, how to collect signals that contain both spindle rotation accuracy and vibration characteristics and effectively process and analyze them is a key issue that needs to be solved in order to achieve online suppression of milling chatter and improve workpiece processing quality. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a complex component milling stability monitoring device, method, system and medium, which can overcome the problem that the wired sensor lines are complicated and cannot rotate with the spindle, and monitor the milling state more comprehensively. It is conducive to accurately tracing different vibration types.

[0006] To achieve the above-mentioned purpose, in the first aspect, the technical solution adopted by the present invention is: a complex component milling processing stability monitoring device, which includes: a rotor module, a stator module, a mounting and fixing module, a data acquisition and transmission module and a sealing module; the rotor module includes an iron core, a hollow shaft, a fixing ring, an induction coil and a magnetic ring; the iron core is installed on the outside of the hollow shaft, the induction coil is wound on the outside of the iron core in the same direction, and the magnetic ring is arranged on the outside of the iron core; a fixing ring is arranged on the outside of the hollow shaft to limit the axial movement of the iron core; the hollow shaft is sleeved on the outside of the tool handle and fixed to the tool handle by bolts; the stator module includes a shell, a permanent magnet, a mounting bracket fixing hole , front / or rear end cover fixing holes, sensor mounting slots and charging interfaces; the permanent magnet is fixed on the inner side of the outer shell, and the rotor module is located on the inner side of the permanent magnet; a sensor mounting slot is arranged on the end face of the outer shell, a charging interface is arranged on the outer side, and mounting bracket fixing holes and front / or rear end cover fixing holes for installation are arranged on the outer shell; the rotor module is arranged on the inner side of the stator module, the stator module outer shell is fixed to the sealing module, and the data acquisition and transmission module is arranged on the sealing module to constitute a complex component milling processing stability monitoring device; and the stator module outer shell is connected to the installation and fixing module by bolts, and then connected to the spindle system outer shell, and the rotor module and the tool holder are fixed together by bolts.

[0007] Furthermore, a plurality of first positioning holes are arranged at intervals on the hollow rotating shaft, and the hollow rotating shaft is fixed to the tool handle through the first positioning holes.

[0008] Further, the mounting and fixing module includes a mounting bracket and connecting bolts;

[0009] The mounting bracket is used to fix the housing, and the housing is connected to the spindle system housing by bolt connection;

[0010] The mounting bracket is provided with a plurality of second positioning holes at intervals, and is used to fix the mounting bracket on the spindle housing;

[0011] A plurality of adjustment holes are arranged at intervals on the mounting bracket, which is connected to the stator module housing through the adjustment holes, and the distance between the monitoring device and the end face of the main shaft housing is adjusted through the adjustment holes.

[0012] Further, the data acquisition and transmission module is arranged on the sealing module, and the data acquisition and transmission module includes a conditioner, a rechargeable battery and a circuit board;

[0013] The conditioner is used to regulate the current generated during the relative movement of the rotor module and the stator module so that it can be stably output to the rechargeable battery;

[0014] A three-dimensional micro acceleration sensor, a conditioning circuit and a data transmitting device are arranged on the circuit board; the three-dimensional micro sensor is used to collect the vibration acceleration generated when the tool handle rotates, and transmit it to the conditioning circuit; after the conditioning circuit converts and pre-processes the collected vibration acceleration signal, the collected information is transmitted to an external data receiving device via the data transmitting device.

[0015] Furthermore, the sealing module includes a front cover, a rear cover and sealing rings at the front and rear ends; the data acquisition and transmission module is connected to the rear cover and is arranged in the sensor installation groove of the stator module housing;

[0016] A cable fixing seat, a cable and a brush are arranged on the inner side surface of the rear end cover, which are used to transmit the generated current to the data acquisition and transmission module;

[0017] A plurality of third positioning holes are arranged at intervals in the circumferential direction of the rear end cover, respectively used for installing the rear end sealing ring and the stator module housing;

[0018] A plurality of fourth positioning holes are arranged at intervals in the axial direction of the front end cover for fixing with the front end sealing ring and the stator module housing;

[0019] A plurality of fifth positioning holes corresponding to the positioning holes on the front end cover and the rear end cover are arranged at intervals on the sealing ring.

[0020] In the second aspect, the technical solution adopted by the present invention is: a method for monitoring the stability of complex component milling processing, which is implemented based on the above-mentioned complex component milling processing stability monitoring device, and comprises: installing the complex component milling processing stability monitoring device on the tool handle, connecting the mounting bracket to the spindle housing, and then connecting the mounting bracket to the stator module housing of the complex component milling processing stability monitoring device through bolts; starting the spindle system, when the spindle rotates, the housing is stationary relative to the shaft, and the hollow shaft rotates with the tool handle to cut the magnetic flux lines, thereby generating current to power the data acquisition and transmission module; by processing and analyzing the acceleration signal collected by the data acquisition and transmission module, the rotation accuracy of the spindle system is obtained; The acceleration signal along the x-axis collected by the transmission module is analyzed, and the fractal dimension, power spectrum entropy, standard deviation, power spectrum entropy difference, sample entropy and sample entropy difference of the signal are calculated respectively to construct a characteristic indicator matrix; the manifold learning algorithm is used to reduce the dimension of the characteristic indicator matrix to obtain a two-dimensional feature matrix containing the intrinsic topological structure of different characteristic indicators; the vibration acceleration signals when the milling state is stable, no-load, slight flutter, and severe flutter are collected respectively to construct a two-dimensional feature matrix of different milling states, and the mapping relationship between the feature matrix and the milling state is established to obtain a milling state mapping model; the milling process stability is monitored online in real time through the constructed milling state recognition model and the calculated spindle rotation accuracy.

[0021] Furthermore, by processing and analyzing the acceleration signal collected by the data acquisition and transmission module, the rotation accuracy of the spindle system is obtained, including:

[0022] When the vibration acceleration sensor rotates with the tool holder, its own coordinate system position changes, and the output acceleration values ​​along the x-axis, y-axis and z-axis of the acceleration coordinate system correspond to the centrifugal acceleration, tangential acceleration and acceleration along the axial direction of the milling cutter when the tool holder rotates.

[0023] The centrifugal acceleration is used to calculate the rotation accuracy of the spindle;

[0024] Set the sampling frequency, spindle speed and cutting parameters, collect data, intercept the vibration acceleration signal collected by the spindle rotating a set number of times for processing and analysis, perform Fourier transform on the original signal, retain only the fundamental frequency and its harmonic components, and assign other frequency components to 0, so as to obtain a vibration acceleration signal containing only the fundamental frequency and its harmonics;

[0025] Analyze the processed vibration acceleration signal, find out the minimum and maximum values ​​of the vibration acceleration collected when the spindle rotates one circle, calculate the difference between the two, calculate the difference between the maximum and minimum values ​​of the vibration acceleration when the spindle rotates to the last circle, and take the average value;

[0026] The obtained average value is integrated twice to obtain the spindle rotation accuracy value;

[0027] The above process is repeated for the axial data collected by the acceleration sensor to obtain the axial runout of the spindle system.

[0028] Furthermore, the milling state recognition model constructed and the spindle rotation accuracy calculated are used to monitor the milling process stability in real time online, including:

[0029] The constructed feature matrix is ​​input into the support vector machine for model training to obtain the milling state recognition model;

[0030] The milling state recognition model is used to analyze the collected vibration acceleration signal in real time and to identify the milling state in real time;

[0031] By calculating the spindle rotation accuracy, the rotation accuracy of the spindle system can be monitored in real time;

[0032] Establish the corresponding relationship between workpiece machining accuracy, milling status and spindle rotation accuracy, and set the spindle system rotation accuracy alarm threshold according to the actual workpiece machining accuracy requirements;

[0033] The spindle system rotation accuracy value and the constructed milling state recognition model are comprehensively adopted to perform real-time identification and monitoring of the milling state.

[0034] In the third aspect, the technical solution adopted by the present invention is: a complex component milling processing stability monitoring system, which includes: an installation module, which installs the complex component milling processing stability monitoring device on the tool handle, connects the installation bracket to the spindle housing, and then connects the installation bracket to the stator module housing of the complex component milling processing stability monitoring device through bolts; a starting module, which starts the spindle system, when the spindle rotates, the housing is stationary relative to the shaft, and the hollow shaft rotates with the tool handle to cut the magnetic flux lines, thereby generating current to power the data acquisition and transmission module; a spindle rotation accuracy module, which obtains the spindle system rotation accuracy by processing and analyzing the acceleration signal collected by the data acquisition and transmission module; an indicator matrix construction module, which processes and analyzes the acceleration signal collected by the data acquisition and transmission module The acceleration signal of the x-axis is analyzed, and the fractal dimension, power spectrum entropy, standard deviation, power spectrum entropy difference, sample entropy and sample entropy difference of the signal are calculated respectively to construct a characteristic indicator matrix; the characteristic matrix acquisition module uses a manifold learning algorithm to reduce the dimension of the characteristic indicator matrix to obtain a two-dimensional characteristic matrix containing the intrinsic topological structure of different characteristic indicators; the state model acquisition module collects vibration acceleration signals when the milling state is stable, no-load, slight flutter, and severe flutter, constructs a two-dimensional characteristic matrix of different milling states, establishes a mapping relationship between the characteristic matrix and the milling state, and obtains a milling state mapping model; the monitoring module performs real-time online monitoring of the milling process stability through the constructed milling state recognition model and the calculated spindle rotation accuracy.

[0035] In a fourth aspect, the technical solution adopted by the present invention is: a computer-readable storage medium storing one or more programs, wherein the one or more programs include instructions, and when the instructions are executed by a computing device, the computing device executes any one of the above methods.

[0036] The present invention adopts the above technical solution, which has the following advantages:

[0037] 1. The present invention adopts a complex component milling processing stability monitoring device to collect vibration acceleration information during the milling process, which can effectively overcome the problem that the wired sensor circuit is redundant and cannot rotate with the main shaft.

[0038] 2. The present invention relies on the relative rotation of the rotor module and the stator module of the device to cut the magnetic flux lines to power the data acquisition system, effectively solving the problem of power supply for wireless sensors.

[0039] 3. The present invention uses the rotational motion of the spindle during milling as the power source of the self-powered technology, and does not require an additional energy source.

[0040] 4. The present invention can collect signals including both the spindle rotation accuracy and the vibration characteristics of the milling system, and can monitor the milling state more comprehensively.

[0041] 5. The present invention uses the intrinsic topological structure of the spindle rotation accuracy and the vibration acceleration signal characteristic index to comprehensively evaluate the milling processing state. The evaluation result is more accurate and comprehensive, which is conducive to accurate tracing of different vibration types. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of a rotor module of a device for monitoring the stability of complex component milling processing according to an embodiment of the present invention;

[0043] Figure 2 Schematic diagram of a stator module of a complex component milling processing stability monitoring device according to an embodiment of the present invention;

[0044] Figure 3 It is a schematic diagram of an installation and fixing module of a complex component milling processing stability monitoring device according to an embodiment of the present invention;

[0045] Figure 4 Schematic diagram of a data acquisition and transmission module of a complex component milling processing stability monitoring device according to an embodiment of the present invention;

[0046] Figure 5 This is a schematic diagram of the data collection and transmission process in an embodiment of the present invention;

[0047] Figure 6 A schematic diagram of a front end cover of a complex component milling processing stability monitoring device according to an embodiment of the present invention;

[0048] Figure 7 A schematic diagram of a rear end cover of a complex component milling processing stability monitoring device according to an embodiment of the present invention;

[0049] Figure 8 Schematic diagram of a sealing ring of a complex component milling processing stability monitoring device according to an embodiment of the present invention;

[0050] Fig. 9 This is a schematic diagram of the installation of various components of the complex component milling processing stability monitoring device in an embodiment of the present invention;

[0051] Fig.10 It is a schematic diagram of the installation of a complex component milling stability monitoring device according to an embodiment of the present invention;

[0052] Fig.11 Schematic diagram of the actual application of the complex component milling stability monitoring device in an embodiment of the present invention;

[0053] Fig.12 This is a flow chart of the calculation of the rotation accuracy of the spindle system in an embodiment of the present invention;

[0054] Fig.13 Schematic diagram of the distance between the sensor mass center and the spindle rotation center in an embodiment of the present invention;

[0055] Fig.14 This is a flow chart of milling process stability monitoring in an embodiment of the present invention;

[0056] Reference numerals:

[0057] Iron core 1; hollow shaft 2; induction coil 3; magnetic ring 4; fixing ring 5; permanent magnet 6; stator module housing 7; sensor mounting slot 8; charging interface 9; mounting bracket fixing hole 10; front and rear end cover fixing holes 11; first positioning hole 12; mounting bracket 13; second positioning hole 14; adjustment hole 15; conditioner 16; rechargeable battery 17; circuit board 18; front end cover 19; rear end cover 20; front and rear end cover sealing ring 21; cable fixing seat 22; cable 23; brush 24; third positioning hole 25; fourth positioning hole 26; fifth positioning hole 27; tool handle 28; spindle housing 29; complex component milling stability monitoring device 30; sensor center of mass 31; spindle rotation center 32. DETAILED DESCRIPTION

[0058] In order to achieve online suppression of milling chatter and improve the quality of workpiece processing, the present invention provides a complex component milling processing stability monitoring device, method, system and medium. The present invention adopts a complex component milling processing stability monitoring device to collect vibration acceleration information during milling processing, which overcomes the problem that the wired sensor line is complicated and cannot rotate with the main shaft. The present invention relies on the relative rotation of the rotor module and the stator module of the device to cut the magnetic flux lines to power the data acquisition system, which effectively solves the problem of wireless sensor power supply. The present invention uses the rotational motion of the spindle during milling as the power source of the self-powered technology, and does not require an additional energy source. The present invention can collect signals that include both the spindle rotation accuracy and the vibration characteristics of the milling system, and can monitor the milling state more comprehensively. The present invention uses the intrinsic topological structure of the spindle rotation accuracy and the vibration acceleration signal characteristic indicators to comprehensively evaluate the milling processing state. The evaluation result is more accurate and comprehensive, which is conducive to accurate tracing of different vibration types.

[0059] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0060] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0061] In one embodiment of the present invention, a complex component milling stability monitoring device is provided, which has self-powered and wireless transmission functions and is used to collect vibration signals during milling. In this embodiment, the device includes: a rotor module, a stator module, a mounting and fixing module, a data acquisition and transmission module, and a sealing module.

[0062] The rotor module includes an iron core 1, a hollow shaft 2, an induction coil 3, a magnetic ring 4 and a fixed ring 5. The iron core 1 is installed on the outside of the hollow shaft 2, the induction coil 3 is wound on the outside of the iron core 1 in the same direction, and the magnetic ring 4 is arranged on the outside of the iron core 1; and a fixed ring 5 is arranged on the outside of the hollow shaft 2, and the fixed ring 5 is located between the hollow shaft 2 and the iron core 1, and the axial movement of the iron core 1 is limited by the fixed ring 5; a plurality of first positioning holes 12 are arranged on the hollow shaft 2, such as Figure 1 shown.

[0063] The stator module includes a permanent magnet 6, a stator module housing 7, a sensor mounting slot 8, a charging interface 9, a mounting bracket fixing hole 10, and a front / or rear end cover fixing hole 11. The permanent magnet 6 is fixed to the inner side of the housing 7, and the rotor module is located on the inner side of the permanent magnet 6. The end surface of the housing 7 is provided with a sensor mounting slot 8, and the outer side is provided with a charging interface 9. The housing 7 is also provided with a mounting bracket fixing hole 10 and a front and rear end cover fixing hole 11 for installation, such as Figure 2 shown.

[0064] The rotor module is arranged on the inner side of the stator module, the stator module housing 7 is fixed to the sealing module, the data acquisition and transmission module is connected to the sealing module, and is arranged in the sensor mounting groove 8 of the housing 7 to form a complex component milling processing stability monitoring device; and the stator module housing is connected to the installation and fixing module by bolts, and then connected to the spindle system housing, and the rotor module and the tool handle are fixed together by bolts.

[0065] When in use, when the main shaft rotates, the housing 7 is stationary, and the rotor module rotates together with the tool handle to cut the magnetic flux lines to generate current, which supplies power to the data acquisition and transmission module.

[0066] In the above embodiment, a plurality of first positioning holes 12 are arranged at intervals on the hollow shaft 2 , and the hollow shaft 2 is fixed to the tool handle through the first positioning holes 12 .

[0067] In the above embodiment, the mounting and fixing module includes a mounting bracket 13 and connecting bolts, etc., wherein the mounting bracket 13 is used to fix the housing 7, and the housing 7 is connected to the spindle system housing by bolt connection. Figure 3 As shown, a plurality of second positioning holes 14 are arranged at intervals on the mounting bracket 13 for fixing the mounting bracket 13 on the spindle housing; in addition, a plurality of adjustment holes 15 are arranged at intervals on the mounting bracket 13, which are connected to the stator module housing 7 through the adjustment holes 15 on the one hand, and the distance between the monitoring device of the present invention and the end face of the spindle housing is adjusted through the adjustment holes 15 on the other hand.

[0068] In the above embodiment, if Figure 4 , Figure 5 As shown, the data acquisition and transmission module is connected to the sealing module and placed in the sensor mounting slot 8 of the stator module housing 7. The data acquisition and transmission module includes a conditioner 16, a rechargeable battery 17 and a circuit board 18. The conditioner 16 is used to condition the current generated during the relative movement of the rotor module and the stator module so that it can be stably output to the rechargeable battery 17. The circuit board 18 is provided with a three-dimensional micro acceleration sensor, a conditioning circuit and a data transmitting device; the three-dimensional micro sensor is used to collect the vibration acceleration generated when the tool handle rotates, and transmit it to the conditioning circuit; the conditioning circuit converts and pre-processes the collected vibration acceleration signal, and transmits the collected information to an external data receiving device through the data transmitting device.

[0069] The data transmitter is a wireless transmitter for transmitting the collected vibration acceleration signal; the data receiver is installed at the signal receiving end for receiving the data transmitted by the data transmitter. The conditioner 16, the rechargeable battery 17, and the circuit board 18 (including the micro acceleration sensor, the wireless transmitter and the conditioning circuit) are installed in the sensor installation slot 8 of the housing 7.

[0070] In the above embodiment, if Figures 6 to 8 As shown, the sealing module includes a front end cover 19 (such as Figure 6 As shown), rear end cover 20 (as Figure 7 As shown) and the front and rear end sealing rings 21 (as shown Figure 8 The data acquisition and transmission module is connected to the rear end cover 20, and a cable fixing seat 22, a cable 23 and a brush 24 are arranged on the inner side of the rear end cover 20, which are used to transmit the current generated during the relative movement of the rotor module and the stator module to the data acquisition and transmission module; and a plurality of third positioning holes 25 are arranged at intervals in the circumferential direction of the rear end cover 20, which are respectively used to install the sealing ring 21 at the rear end and the stator module housing 7. A plurality of fourth positioning holes 26 are arranged at intervals in the axial direction of the front end cover 19, which are used to fix the sealing ring 21 at the front end, and a plurality of fifth positioning holes 27 corresponding to the positioning holes on the front end cover 19 and the rear end cover 20 are arranged at intervals on the sealing ring 21.

[0071] In the above embodiments, Fig. 9 As shown, the rear end cover 20 is fixed to the stator module housing 7 by bolt connection, and a sealing ring 21 is installed between the two. Then the permanent magnet 6 is fixed to the inner side of the stator; the iron core 1 with the induction coil 3 is sleeved on the outer side of the hollow shaft 2, and the axial movement of the iron core 1 is limited by the fixing ring 5; then the front end cover sealing ring 21 and the front end cover 19 are installed in sequence, and the installation operation of the wireless self-powered data acquisition device can be completed.

[0072] In one embodiment of the present invention, a method for monitoring the stability of milling of a complex component is provided. The method is implemented based on the monitoring device for the stability of milling of a complex component in the above embodiments, and is used to collect vibration signals during the milling process, and then process and analyze the vibration signals to implement an online monitoring method for the stability of milling of a complex component. In this embodiment, the method includes the following steps:

[0073] 1) Install the complex component milling stability monitoring device on the tool holder 28, connect the mounting bracket 13 to the spindle housing 29, and then connect the mounting bracket 13 to the stator module housing 7 of the complex component milling stability monitoring device 30 by bolt connection, as shown in FIG. Fig.10 , Fig.11 shown.

[0074] In this embodiment, the data acquisition and transmission module can be charged through the external charging interface 9 on the stator module housing 7, and the data acquisition and transmission module can also be powered by the current generated by the rotation of the device with the handle.

[0075] 2) After the monitoring device is installed, start the spindle system. Since the stator module housing 7 is fixed to the spindle housing 29 through the mounting bracket 13, the housing 7 is stationary relative to the shaft when the spindle rotates. The hollow shaft 2 rotates with the tool handle to cut the magnetic flux lines, thereby generating current to power the data acquisition and transmission module.

[0076] In this embodiment, the generated current is processed by the conditioner 16 to form a stable current, which continuously charges the rechargeable battery 17. The rechargeable battery 17 supplies power to the circuit board 18 to provide power for the sensor's signal acquisition and data transmission.

[0077] In actual applications, the signals collected by the vibration sensor are sent to the receiving end via a wireless transmission device to achieve signal collection, transmission and storage. The collected data can then be analyzed in real time to monitor the spindle rotation accuracy and milling cutter vibration status in real time.

[0078] 3) The rotation accuracy of the spindle system is obtained by processing and analyzing the acceleration signal collected by the data acquisition and transmission module.

[0079] 4) Analyze the acceleration signal along the x-axis collected by the data acquisition and transmission module, and calculate the fractal dimension, power spectrum entropy, standard deviation, power spectrum entropy difference, sample entropy and sample entropy difference of the signal respectively, and use the above six indicators to construct a characteristic indicator matrix.

[0080] 5) The manifold learning algorithm is used to reduce the dimension of the feature indicator matrix to obtain a two-dimensional feature matrix containing the intrinsic topological structure of different feature indicators.

[0081] 6) Collect vibration acceleration signals when the milling states are stable, no-load, slight vibration, and severe vibration, respectively, and use steps 4) to 5) to construct a two-dimensional feature matrix of different milling states, establish a mapping relationship between the feature matrix and the milling state, and obtain a milling state mapping model.

[0082] 7) The milling process stability is monitored online in real time through the constructed milling state recognition model and the calculated spindle rotation accuracy.

[0083] In the above step 3), the acceleration signal collected by the data acquisition and transmission module is processed and analyzed to obtain the rotation accuracy of the spindle system, such as Fig.12 As shown, the following steps are included:

[0084] 3.1) During the actual machining process, the vibration acceleration sensor changes its own coordinate system position as the tool holder rotates. The output acceleration values ​​along the x-axis, y-axis and z-axis of the acceleration coordinate system correspond to the centrifugal acceleration, tangential acceleration and acceleration along the axial direction of the milling cutter when the tool holder rotates, respectively.

[0085] 3.2) Use centrifugal acceleration to calculate the rotation accuracy of the spindle.

[0086] like Fig.13 As shown, theoretically, if the spindle has no radial runout (rotation error), the distance between the acceleration sensor and the center of rotation is a constant value. From formula (1), it can be seen that the centrifugal acceleration is a fixed value at a given speed. When the spindle runs radially, the distance between the acceleration sensor and the center of rotation changes, and the output acceleration value changes accordingly.

[0087] a=R·(2·Ω·π / 60) 2 (1)

[0088] Wherein, R is the actual distance between the acceleration sensor mass center 31 and the spindle rotation center 32, a is the acceleration, which can be obtained through the actual reading of the acceleration sensor; Ω is the spindle speed.

[0089] 3.3) Set the sampling frequency, spindle speed and cutting parameters to collect data. Intercept the vibration acceleration signal collected after the spindle rotates a set number of times (for example, 30 times) for processing and analysis. In order to eliminate the influence of noise signals that are not related to the rotation accuracy, perform Fourier transform on the original signal, retain only the fundamental frequency and its harmonic components, and assign other frequency components to 0, so as to obtain a vibration acceleration signal containing only the fundamental frequency and its harmonics.

[0090] 3.4) Analyze the vibration acceleration signal processed in step 3.3), find out the minimum and maximum values ​​of the vibration acceleration collected when the spindle rotates one circle, calculate the difference between the two, calculate the difference between the maximum and minimum values ​​of the vibration acceleration when the spindle rotates the last number of circles (for example, 30 circles), and take the average value.

[0091] 3.5) Integrate the average value twice to get the spindle rotation accuracy value.

[0092] 3.6) Repeat steps 3.3) to 3.5) for the axial data collected by the acceleration sensor to obtain the axial runout of the spindle system.

[0093] In the above step 7), the milling process stability is monitored online in real time through the constructed milling state recognition model and the calculated spindle rotation accuracy, such as Fig.14 As shown, the following steps are included:

[0094] 7.1) Input the constructed feature matrix into the support vector machine for model training to obtain the milling state recognition model.

[0095] 7.2) The milling state recognition model is used to analyze the collected vibration acceleration signal in real time and make real-time judgment on the milling state.

[0096] 7.3) The spindle rotation accuracy is calculated using the method in step 3) and the rotation accuracy of the spindle system is monitored in real time.

[0097] 7.4) Establish the corresponding relationship between the workpiece machining accuracy, milling status and spindle rotation accuracy, and set the spindle system rotation accuracy alarm threshold according to the actual workpiece machining accuracy requirements.

[0098] 7.5) The spindle system rotation accuracy value and the constructed milling state recognition model are used to perform real-time identification and monitoring of the milling state. If the spindle rotation accuracy exceeds the threshold or the milling process generates vibration, the processing equipment needs to be checked or the processing parameters need to be adjusted.

[0099] In one embodiment of the present invention, a complex component milling machining stability monitoring system is provided, comprising:

[0100] Installing the module, installing the complex component milling machining stability monitoring device on the tool holder, connecting the mounting bracket to the spindle housing, and then connecting the mounting bracket to the stator module housing of the complex component milling machining stability monitoring device through bolt connection;

[0101] The starting module starts the spindle system. When the spindle rotates, the housing is stationary relative to the shaft, and the hollow shaft rotates with the tool handle to cut the magnetic flux lines, thereby generating current to power the data acquisition and transmission module.

[0102] The spindle rotation accuracy module processes and analyzes the acceleration signal collected by the data acquisition and transmission module to obtain the spindle system rotation accuracy;

[0103] The indicator matrix construction module analyzes the acceleration signal along the x-axis collected by the data acquisition and transmission module, and calculates the fractal dimension, power spectrum entropy, standard deviation, power spectrum entropy difference, sample entropy and sample entropy difference of the signal to construct a characteristic indicator matrix;

[0104] The feature matrix acquisition module uses the manifold learning algorithm to reduce the dimension of the feature indicator matrix and obtain a two-dimensional feature matrix containing the intrinsic topological structure of different feature indicators;

[0105] The state model acquisition module collects vibration acceleration signals when the milling state is stable, no-load, slight vibration, and severe vibration, constructs a two-dimensional feature matrix of different milling states, establishes a mapping relationship between the feature matrix and the milling state, and obtains a milling state mapping model;

[0106] The monitoring module performs real-time online monitoring of milling process stability through the constructed milling state recognition model and the calculated spindle rotation accuracy.

[0107] In the above embodiment, the rotation accuracy of the spindle system is obtained by processing and analyzing the acceleration signal collected by the data acquisition and transmission module, including:

[0108] When the vibration acceleration sensor rotates with the tool holder, its own coordinate system position changes, and the output acceleration values ​​along the x-axis, y-axis and z-axis of the acceleration coordinate system correspond to the centrifugal acceleration, tangential acceleration and acceleration along the axial direction of the milling cutter when the tool holder rotates.

[0109] The centrifugal acceleration is used to calculate the rotation accuracy of the spindle;

[0110] Set the sampling frequency, spindle speed and cutting parameters, collect data, intercept the vibration acceleration signal collected by the spindle rotating a set number of times for processing and analysis, perform Fourier transform on the original signal, retain only the fundamental frequency and its harmonic components, and assign other frequency components to 0, so as to obtain a vibration acceleration signal containing only the fundamental frequency and its harmonics;

[0111] Analyze the processed vibration acceleration signal, find out the minimum and maximum values ​​of the vibration acceleration collected when the spindle rotates one circle, calculate the difference between the two, calculate the difference between the maximum and minimum values ​​of the vibration acceleration when the spindle rotates the last number of circles, and take the average value;

[0112] The obtained average value is integrated twice to obtain the spindle rotation accuracy value;

[0113] The above process is repeated for the axial data collected by the acceleration sensor to obtain the axial runout of the spindle system.

[0114] In the above embodiment, the milling process stability is monitored online in real time by using the constructed milling state recognition model and the calculated spindle rotation accuracy, including:

[0115] The constructed feature matrix is ​​input into the support vector machine for model training to obtain the milling state recognition model;

[0116] The milling state recognition model is used to analyze the collected vibration acceleration signal in real time and to identify the milling state in real time;

[0117] By calculating the spindle rotation accuracy, the rotation accuracy of the spindle system can be monitored in real time;

[0118] Establish the corresponding relationship between workpiece machining accuracy, milling status and spindle rotation accuracy, and set the spindle system rotation accuracy alarm threshold according to the actual workpiece machining accuracy requirements;

[0119] The spindle system rotation accuracy value and the constructed milling state recognition model are comprehensively adopted to perform real-time identification and monitoring of the milling state.

[0120] The system provided in this embodiment is used to execute the above-mentioned method embodiments. Please refer to the above-mentioned embodiments for specific processes and detailed contents, which will not be repeated here.

[0121] In one embodiment of the present invention, a computing device is provided, which may be a terminal, and may include: a processor, a communication interface, a memory, a display screen, and an input device. Among them, the processor, the communication interface, and the memory communicate with each other through a communication bus. The processor is used to provide computing and control capabilities. The memory includes a non-volatile storage medium and an internal memory, and the non-volatile storage medium stores an operating system and a computer program. When the computer program is executed by the processor, the method in each of the above embodiments is implemented; the internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a management network, NFC (near field communication) or other technologies. The display screen may be a liquid crystal display screen or an electronic ink display screen, and the input device may be a touch layer covered on the display screen, or a key, trackball or touchpad provided on the housing of the computing device, or an external keyboard, touchpad or mouse, etc. The processor may call the logic instructions in the memory.

[0122] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0123] In one embodiment of the present invention, a computer program product is provided, wherein the computer program product includes a computer program stored on a non-transitory computer-readable storage medium, wherein the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the methods provided by the above-mentioned method embodiments.

[0124] In one embodiment of the present invention, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium stores server instructions, and the computer instructions enable a computer to execute the methods provided in the above embodiments.

[0125] The above embodiment provides a computer-readable storage medium, whose implementation principle and technical effect are similar to those of the above method embodiment, and will not be repeated here.

[0126] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0127] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0128] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A complex component milling stability monitoring device, characterized in that: include: Rotor module, stator module, installation and fixing module, data acquisition and transmission module and sealing module; The rotor module includes an iron core, a hollow shaft, a fixing ring, an induction coil and a magnetic ring; the iron core is installed on the outside of the hollow shaft, the induction coil is wound on the outside of the iron core in the same direction, and the magnetic ring is arranged on the outside of the iron core; a fixing ring is arranged on the outside of the hollow shaft to limit the axial movement of the iron core; the hollow shaft is sleeved on the outside of the tool handle and fixed to the tool handle by bolts; The stator module includes a housing, a permanent magnet, a mounting bracket fixing hole, a front / or rear end cover fixing hole, a sensor mounting slot and a charging interface; the permanent magnet is fixed on the inner side of the housing, and the rotor module is located on the inner side of the permanent magnet; a sensor mounting slot is provided on the end face of the housing, a charging interface is provided on the outer side, and a mounting bracket fixing hole and a front / or rear end cover fixing hole for installation are provided on the housing; The rotor module is arranged on the inner side of the stator module, the stator module shell is fixed to the sealing module, and the data acquisition and transmission module is arranged on the sealing module to form a complex component milling processing stability monitoring device; and the stator module shell is connected to the installation and fixing module by bolts, and then connected to the spindle system shell, and the rotor module and the tool handle are fixed together by bolts.

2. The complex component milling stability monitoring device according to claim 1, characterized in that: A plurality of first positioning holes are arranged at intervals on the hollow rotating shaft, and the hollow rotating shaft and the tool handle are fixed through the first positioning holes.

3. The complex component milling stability monitoring device according to claim 1, characterized in that: The installation and fixing module includes a mounting bracket and connecting bolts; The mounting bracket is used to fix the housing, and the housing is connected to the spindle system housing by bolt connection; The mounting bracket is provided with a plurality of second positioning holes at intervals, and is used to fix the mounting bracket on the spindle housing; A plurality of adjustment holes are arranged at intervals on the mounting bracket, which is connected to the stator module housing through the adjustment holes, and the distance between the monitoring device and the end face of the main shaft housing is adjusted through the adjustment holes.

4. The complex component milling stability monitoring device according to claim 1, characterized in that: The data acquisition and transmission module is arranged on the sealing module, and the data acquisition and transmission module comprises a conditioner, a rechargeable battery and a circuit board; The conditioner is used to regulate the current generated during the relative movement of the rotor module and the stator module so that it can be stably output to the rechargeable battery; A three-dimensional micro acceleration sensor, a conditioning circuit and a data transmitting device are arranged on the circuit board; the three-dimensional micro sensor is used to collect the vibration acceleration generated when the tool handle rotates, and transmit it to the conditioning circuit; after the conditioning circuit converts and pre-processes the collected vibration acceleration signal, the collected information is transmitted to an external data receiving device via the data transmitting device.

5. The complex component milling stability monitoring device according to claim 1, characterized in that: The sealing module includes a front cover, a rear cover and sealing rings at the front and rear ends; the data acquisition and transmission module is connected to the rear cover and is arranged in the sensor installation groove of the stator module housing; A cable fixing seat, a cable and a brush are arranged on the inner side surface of the rear end cover, which are used to transmit the generated current to the data acquisition and transmission module; A plurality of third positioning holes are arranged at intervals in the circumferential direction of the rear end cover, respectively used for installing the rear end sealing ring and the stator module housing; A plurality of fourth positioning holes are arranged at intervals in the axial direction of the front end cover for fixing with the front end sealing ring and the stator module housing; A plurality of fifth positioning holes corresponding to the positioning holes on the front end cover and the rear end cover are arranged at intervals on the sealing ring.

6. A method for monitoring the stability of complex component milling, implemented based on the complex component milling stability monitoring device according to any one of claims 1 to 5, characterized in that: include: The complex component milling machining stability monitoring device is installed on the tool holder, the installation bracket is connected to the spindle housing, and then the installation bracket is connected to the stator module housing of the complex component milling machining stability monitoring device through bolt connection; Start the spindle system. When the spindle rotates, the housing is stationary relative to the shaft. The hollow shaft rotates with the tool handle to cut the magnetic flux lines, thereby generating current to power the data acquisition and transmission module. By processing and analyzing the acceleration signal collected by the data acquisition and transmission module, the rotation accuracy of the spindle system is obtained; The acceleration signal along the x-axis collected by the data acquisition and transmission module is analyzed, and the fractal dimension, power spectrum entropy, standard deviation, power spectrum entropy difference, sample entropy and sample entropy difference of the signal are calculated respectively to construct a characteristic indicator matrix; The manifold learning algorithm is used to reduce the dimension of the feature index matrix to obtain a two-dimensional feature matrix containing the intrinsic topological structure of different feature indexes. The vibration acceleration signals of stable, no-load, slight vibration and severe vibration milling states are collected respectively, and a two-dimensional feature matrix of different milling states is constructed. The mapping relationship between the feature matrix and the milling state is established to obtain the milling state mapping model. Through the constructed milling state recognition model and the calculated spindle rotation accuracy, the milling process stability is monitored in real time online.

7. The method for monitoring the stability of complex component milling as claimed in claim 6, characterized in that: By processing and analyzing the acceleration signal collected by the data acquisition and transmission module, the rotation accuracy of the spindle system is obtained, including: When the vibration acceleration sensor rotates with the tool holder, its own coordinate system position changes, and the output acceleration values ​​along the x-axis, y-axis and z-axis of the acceleration coordinate system correspond to the centrifugal acceleration, tangential acceleration and acceleration along the axial direction of the milling cutter when the tool holder rotates. The centrifugal acceleration is used to calculate the rotation accuracy of the spindle; Set the sampling frequency, spindle speed and cutting parameters, collect data, intercept the vibration acceleration signal collected by the spindle rotating a set number of times for processing and analysis, perform Fourier transform on the original signal, retain only the fundamental frequency and its harmonic components, and assign other frequency components to 0, so as to obtain a vibration acceleration signal containing only the fundamental frequency and its harmonics; Analyze the processed vibration acceleration signal, find out the minimum and maximum values ​​of the vibration acceleration collected when the spindle rotates one circle, calculate the difference between the two, calculate the difference between the maximum and minimum values ​​of the vibration acceleration when the spindle rotates to the last circle, and take the average value; The obtained average value is integrated twice to obtain the spindle rotation accuracy value; The above process is repeated for the axial data collected by the acceleration sensor to obtain the axial runout of the spindle system.

8. The method for monitoring the stability of complex component milling as claimed in claim 6, characterized in that: Through the constructed milling state recognition model and the calculated spindle rotation accuracy, the milling process stability is monitored online in real time, including: The constructed feature matrix is ​​input into the support vector machine for model training to obtain the milling state recognition model; The milling state recognition model is used to analyze the collected vibration acceleration signal in real time and to identify the milling state in real time; By calculating the spindle rotation accuracy, the rotation accuracy of the spindle system can be monitored in real time; Establish the corresponding relationship between workpiece machining accuracy, milling status and spindle rotation accuracy, and set the spindle system rotation accuracy alarm threshold according to the actual workpiece machining accuracy requirements; The spindle system rotation accuracy value and the constructed milling state recognition model are comprehensively adopted to perform real-time identification and monitoring of the milling state.

9. A complex component milling stability monitoring system, characterized in that: include: Installing the module, installing the complex component milling machining stability monitoring device on the tool holder, connecting the mounting bracket to the spindle housing, and then connecting the mounting bracket to the stator module housing of the complex component milling machining stability monitoring device through bolt connection; The starting module starts the spindle system. When the spindle rotates, the housing is stationary relative to the shaft, and the hollow shaft rotates with the tool handle to cut the magnetic flux lines, thereby generating current to power the data acquisition and transmission module. The spindle rotation accuracy module processes and analyzes the acceleration signal collected by the data acquisition and transmission module to obtain the spindle system rotation accuracy; The indicator matrix construction module analyzes the acceleration signal along the x-axis collected by the data acquisition and transmission module, and calculates the fractal dimension, power spectrum entropy, standard deviation, power spectrum entropy difference, sample entropy and sample entropy difference of the signal to construct a characteristic indicator matrix; The feature matrix acquisition module uses the manifold learning algorithm to reduce the dimension of the feature indicator matrix and obtain a two-dimensional feature matrix containing the intrinsic topological structure of different feature indicators; The state model acquisition module collects vibration acceleration signals when the milling state is stable, no-load, slight vibration, and severe vibration, constructs a two-dimensional feature matrix of different milling states, establishes a mapping relationship between the feature matrix and the milling state, and obtains a milling state mapping model; The monitoring module performs real-time online monitoring of milling process stability through the constructed milling state recognition model and the calculated spindle rotation accuracy.

10. A computer-readable storage medium storing one or more programs, characterized in that: The one or more programs include instructions, which, when executed by a computing device, cause the computing device to perform any one of the methods of claims 6 to 8.

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