Active control device and method for machining elastic deformation of thin-wall annular part

Abstract

In order to solve the technical problem that an existing mechanical auxiliary support cannot achieve elastic deformation control in the milling machining process of a thin-wall annular part, the invention provides an active control device and method for machining elastic deformation of the thin-wall annular part. The clamping module is set up, and positioning and clamping of the thin-wall annular part are achieved; an active supporting module is designed, controllable supporting force is applied to the inner molded surface of the thin-wall annular part through a plurality of independent supporting devices with the controllable supporting force, and a foundation is provided for active control over elastic deformation in the milling machining process; the deformation monitoring module and the regulation and control module are combined, active control over elastic deformation in the machining process of the thin-wall annular part is achieved for the first time, and the problem of elastic deformation caused by introduction of milling force in the machining process of the thin-wall annular part is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing, and relates to an active control device and method for elastic deformation during processing of thin-walled annular parts. Background Art

[0002] Thin-walled annular parts are widely used in aircraft due to their light weight and compact structure, such as aircraft engine casings and missile control compartment housings. The manufacturing quality of such thin-walled annular parts is the key to the long-term stable service performance of aircraft in complex and extreme working environments such as high temperature, high pressure and high speed. Therefore, their processing quality needs to be strictly controlled. However, thin-walled annular parts have the characteristics of weak rigidity, low strength and difficult material processing. Under the action of cutting force, they will inevitably cause different degrees of deformation during the processing process, thus affecting the processing quality.

[0003] In order to improve the processing quality of thin-walled annular parts, it is necessary to control their deformation during processing. However, most existing deformation control methods pay little attention to the time-varying factors during the workpiece processing. Usually, a fixed support force is applied to the workpiece in advance through a mechanical structure, which makes it difficult to achieve active control of elastic deformation during the processing. Therefore, the effect of improving the processing quality of annular thin-walled parts is not ideal.

[0004] The patent document with publication number CN115922226A discloses an adaptive processing tooling and adaptive processing method for thin-walled cylinders. In this scheme, the radial support device and the radial adsorption device are driven according to the pressure signal to adaptively adjust the processing deformation of the parts. This scheme has a certain inhibitory effect on the elastic deformation during the processing, but for milling, factors such as the weak rigidity of the workpiece, the non-uniformity of the material and the wear of the tool will lead to strong time-varying cutting force. This scheme only adjusts the real-time deformation based on the pressure signal, which has certain defects: on the one hand, the response of the radial support device has a lag, and there may be a certain amount of error that is not compensated in time; on the other hand, as the process progresses, these errors that are not compensated in time will gradually accumulate, resulting in the elastic deformation of the workpiece during processing cannot be effectively controlled, and ultimately resulting in out-of-tolerance. Summary of the invention

[0005] In order to solve the problem that the existing scheme for controlling machining deformation cannot timely compensate for the deformation during machining and cannot effectively control the elastic deformation during machining, the present invention provides an active control device and method for machining elastic deformation of thin-walled annular parts.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0007] An active control device for elastic deformation of thin-walled annular parts processing, which is special in that it includes a clamping module, an active support module, a deformation monitoring module and a control module;

[0008] The clamping module is used to perform circumferential positioning and axial clamping of the processed thin-walled annular parts;

[0009] The active support module is used to provide adjustable, multiple independent, equal radial support forces to the inner surface of the thin-walled annular part; the active support module has a support force detection function and can send the support force it provides to the control module;

[0010] The deformation monitoring module is used to monitor the elastic deformation of thin-walled annular parts during processing;

[0011] The control module is used to control the operation of the active support module and the deformation monitoring module. The control module also has preset elastic deformation prediction models and support force control curves for each processing node.

[0012] The control module uses closed-loop feedback control within the process to adjust the support force provided by the active support module based on the support force data detected by the active support module and the support force control curve; it can also process the support force data detected by the active support module and the elastic deformation data detected by the deformation monitoring module before the start of the next process, so as to obtain the actual deformation field of the thin-walled annular part in the previous process, and compare the actual deformation field with the deformation field of the previous process predicted by the elastic deformation prediction model to obtain the support force compensation amount of the next process, and issue a support force control instruction to the active support module before the start of the next process based on the support force compensation amount and the support force control curve, so as to realize support force control between processes.

[0013] Furthermore, the clamping module includes a clamping sub-module and a positioning sub-module; the clamping sub-module includes a clamping base plate, a double-headed flange support column and a clamping cover plate connected in sequence from bottom to top, and the thin-walled annular part is clamped by the clamping base plate and the clamping cover plate; the positioning sub-module includes at least three positioning rings arranged on the clamping base plate and distributed along the same circumference, and the outer wall of the positioning ring is adapted to the inner wall profile of the thin-walled annular part.

[0014] Furthermore, the upper surface of the clamping base plate is provided with a plurality of arc holes, a plurality of strip grooves and a plurality of mounting holes; the arc holes and the strip grooves are used for discharging coolant during processing; the mounting holes are used for installing the positioning submodule; the mounting holes are provided in multiple groups, and each group is distributed on a circumference of different sizes so as to adjust the positioning dimensions of the positioning submodule.

[0015] Furthermore, the active support module includes a driving device arranged on the clamping base plate and an execution device with a support force detection function; there are m execution devices and they are evenly distributed along the same circumference, and they can independently move radially under the drive of the driving device to support the inner wall of the thin-walled annular part; the driving device is connected to the control module, and its operation is controlled by the control module; m≥3;

[0016] The actuator is a pneumatic actuator, an electric actuator or a hydraulic actuator, and correspondingly, the drive device is a pneumatic drive device, an electric drive device or a hydraulic drive device.

[0017] Furthermore, the actuator is a pneumatic actuator, including a support base and m support devices; the legs of the support base are fixedly mounted on the clamping base plate, and the table of the support base is used to support and mount the m support devices; a single support device includes a cylinder, a sensor connecting plate, a pressure sensor, a support head connecting plate and an inner surface support head connected in sequence; the cylinder is mounted on the table of the support base, and the sensor connecting plate is fixedly connected to the push rod of the cylinder; the sensor connecting plate is connected to the support head connecting plate by clamping bolts;

[0018] The driving device is a pneumatic driving device, including m driving groups arranged on the clamping base plate; a single driving group includes a solenoid valve, an electric proportional valve and a signal converter arranged on the clamping base plate; the solenoid valve and the electric proportional valve are connected to the cylinder, the electric proportional valve is used to adjust the gas pressure entering the cylinder to a specified air pressure, and the solenoid valve is used to transmit the gas of the specified air pressure to the cylinder; the signal converter is connected to the pressure sensor, and is used to convert the electrical signal output by the pressure sensor into a signal recognizable by the control module.

[0019] Furthermore, the active support module is one or more; when there are multiple active support modules, they are arranged in sequence along the axial direction and used in combination to support different axial regions of the thin-walled annular component.

[0020] Furthermore, the deformation monitoring module includes m deformation monitoring devices arranged on the table top of the support base; the m deformation monitoring devices are evenly distributed along the circumferential direction, and a deformation monitoring device is provided between every two support devices; a single deformation monitoring device includes a displacement sensor and a front box; the displacement sensor is installed on the table top of the support base through a displacement sensor mounting plate, and the displacement sensor is used to detect the elastic deformation of the inner surface of the thin-walled annular part; the front box is used to provide the power required by the displacement sensor and to amplify, detect and filter the signal output by the displacement sensor.

[0021] Furthermore, the control module includes an industrial computer, a PLC, a digital-to-analog conversion module, a data acquisition module, a power supply and an air compressor; the elastic deformation prediction model is preset on the industrial computer; the support force control curve of each processing node is preset in the PLC, and the corresponding relationship between the voltage signal and the air pressure value is set in the PLC;

[0022] Before the processing procedure starts, the industrial computer sends a first control instruction to the PLC, and the PLC cooperates with the digital-to-analog conversion module to send corresponding analog signals to all the electrical proportional valves of the pneumatic drive device in the active support module according to the received first control instruction and based on the support force control curve, so as to set the initial air source pressure; then, the PLC sends digital signals to all the solenoid valves of the pneumatic drive device in the active support module through the IO port to control the synchronous extension and retraction of all the cylinders of the pneumatic actuator in the active support module, so as to set the initial state of the active support module;

[0023] Then, the PLC sends a first request instruction to all the pressure sensors of the pneumatic actuators in the active support module. The data acquisition module reads the monitoring values ​​of each pressure sensor in the active support module to the PLC, and the PLC compares the support force monitoring value with the support force setting value. If there is inconsistency and it needs to be adjusted to the setting value, the PLC uses the PID algorithm in conjunction with the digital-to-analog conversion module to perform feedback adjustment until the active support module provides the required support force to the thin-walled annular part, and then starts the normal milling program;

[0024] During the processing, the industrial computer sends a second request instruction to the displacement sensor in the deformation monitoring module. The data acquisition module reads the monitoring values ​​of all displacement sensors to the industrial computer, and the industrial computer performs data fitting to obtain the actual deformation field of the inner surface of the thin-walled annular part. The industrial computer then compares the actual deformation field with the workpiece deformation field predicted by the elastic deformation prediction model, and calculates the support force compensation required for the next process through Hooke's law. All support devices correspond to the same support force compensation.

[0025] Between processes, the industrial computer determines the required supporting force based on the supporting force compensation amount of the next process obtained previously and transmits it to the PLC. The PLC then converts the supporting force into air pressure value to determine the air pressure value required after supporting force compensation. The PLC sends an analog signal corresponding to the compensated air pressure value to all electrical proportional valves of the pneumatic drive device in the active support module through the digital-to-analog conversion module, thereby realizing adaptive adjustment of the supporting force.

[0026] The present invention also provides a method for actively controlling elastic deformation of thin-walled annular parts during machining, which is special in that it comprises the following steps:

[0027] Step 1: Obtain the deformation field and stiffness field after each process is completed, as well as the support force control curve in each process;

[0028] Step 1.1 Create a CAD model after each process and import it into the finite element simulation software;

[0029] Step 1.2: Determine the range of fixed support force corresponding to each process according to the milling force in the process calibrated by the experiment;

[0030] Step 1.3 For each process, within the range of the corresponding fixed support force, k fixed support force values ​​are selected according to the set step length, and a group of first elastic deformation prediction models are established for it based on the CAD model after the process is completed and through finite element simulation. The group of first elastic deformation prediction models includes k models, which correspond to k fixed support force values ​​one by one; s processes need to construct s groups of first elastic deformation prediction models; after the model is established, set the model parameters, including milling force, support force, boundary conditions, material properties, and contact conditions, wherein the milling force is obtained by experimental calibration, and the support force is the k fixed support force values ​​selected according to the set step length;

[0031] Step 1.4: For each process, a milling path is set, and the milling path includes n processing nodes. After simulation, k sets of elastic deformation data can be obtained for the n processing nodes of each process.

[0032] Step 1.5: For each process, a data set is constructed with k groups of elastic deformation data and corresponding fixed support force values ​​corresponding to each processing node in the process, and the functional relationship between the elastic deformation and the support force at each processing node in the process is solved by the numerical fitting method. The elastic deformation is constrained within the tolerance range of the design requirements by setting constraint conditions, and the functional relationship is solved to obtain the target support force of each processing node in the process;

[0033] Step 1.6 For each process, perform function interpolation and fitting on the target support force of each processing node in the process to obtain the support force control curve of each processing node in the process; a total of s support force control curves are obtained for s processes;

[0034] Step 1.7: Establish a second elastic deformation prediction model for each process through finite element simulation, and set the parameters of the elastic deformation prediction model, including milling force, support force, boundary conditions, material properties, and contact conditions; the milling force is still the milling force calibrated by the experiment, and the support force is determined according to the support force control curve of each processing node of the process; a total of s second elastic deformation prediction models need to be established for s processes;

[0035] Step 1.8 For each process, a milling path is first set, and the milling path includes n processing nodes. After simulation, the elastic deformation data of the n processing nodes in the process after processing can be obtained. Each processing node corresponds to an elastic deformation data; the elastic deformation data is arranged according to the position of the processing node, and the deformation field of the workpiece after the process is completed can be obtained;

[0036] Step 1.9 calculates the stiffness field of the workpiece according to the deformation field of the workpiece after each process is completed;

[0037] Step 2: In the current processing step, based on the support force control curve of each processing node of the process obtained in step 1.6, the support force provided by all support devices used to support the inner wall of the thin-walled annular part is adjusted within the process by adopting a closed-loop feedback control method;

[0038] Step 3: After the current process is completed, obtain the support force compensation amount of the next process;

[0039] Step 3.1: select z characteristic points in the rigid weak area on the inner surface of the thin-walled annular component, and set an elastic deformation detection device at each characteristic point, and use these elastic deformation monitoring devices to obtain measured data of elastic deformation at the z characteristic points;

[0040] Step 3.2: setting z elastic deformation extraction points corresponding to the z feature points on the second elastic deformation prediction model, and obtaining the prediction data of elastic deformation at the z feature points after simulation;

[0041] Step 3.3 After the current process is completed, the measured data of elastic deformation at z feature points are compared with the predicted data to obtain the elastic deformation prediction error, and then the support force compensation amount is obtained. The support force compensation amount is used to compensate the support force preset value of each processing node in the next process respectively. The support force preset value is a value determined according to the support force control curve;

[0042] Step 4: The support force compensation amount of the next process determined in step 3 is respectively superimposed with the support force preset value corresponding to each processing node in the next process on the support force control curve, that is, the actual support force required by each processing node in the next process is obtained, and the actual support force is used as the support force provided by all support devices for supporting the inner wall of the thin-walled annular part;

[0043] Step 5: Repeat steps 2-4 until all processes are completed.

[0044] Furthermore, the method for obtaining the supporting force compensation amount is:

[0045] In any current process, the actual cutting depth of the workpiece can be expressed as de,i=dp,i+ei, where d e,iand dp,i are the actual cutting depth and designed cutting depth in the process, respectively, and ei is the machining error of each machining position;

[0046] The support force compensation is ΔF s =K G ·e i , where K G is the workpiece stiffness field obtained in step 1 using the second elastic deformation prediction model.

[0047] The beneficial effects of the present invention are as follows:

[0048] 1. The present invention utilizes a clamping module to position and clamp thin-walled annular parts, utilizes an active support module to apply required support force to thin-walled annular parts, utilizes a deformation monitoring module to monitor the actual deformation of thin-walled annular parts during processing, and utilizes a control module to adjust the support force applied by the active support module to the thin-walled annular parts in the next process according to the actual deformation and the predicted processing deformation, thereby achieving the required support force applied to the weak rigidity area of ​​the thin-walled annular parts at different processing stages, effectively improving the elastic deformation problem of thin-walled annular parts during processing, and improving its processing quality.

[0049] 2. The present invention can establish a support force control curve in advance according to the characteristics of the thin-walled annular part, and can realize inner surface support with controllable support force by using an active support module alone or in combination with multiple active support modules. In addition, in response to the fluctuation of cutting force, the pressure sensor signal is read in real time by PLC, and the active support module is controlled to perform real-time support force control.

[0050] 3. The present invention monitors the deformation of the workpiece in real time during the processing through the deformation monitoring module, obtains the deformation field of the thin-walled annular part in the previous process through the joint control module between processes, provides a reference for the supporting force provided by each supporting device in the active supporting module in the next process, compensates for the error accumulation caused by time-varying factors in the processing process, and avoids workpiece deviation caused by error accumulation.

[0051] 4. The present invention realizes deformation control of the entire process of thin-walled annular parts through the combined use of support force regulation within the process and support force compensation between processes. During use, there is no need to remove the clamp or manually adjust the lateral support device, thereby reducing errors introduced by human factors. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic structural diagram of the active control device for elastic deformation of thin-walled annular parts processing according to the present invention.

[0053] Figure 2 It is a schematic structural diagram of the clamping submodule in the present invention.

[0054] Figure 3 It is a structural schematic diagram of the positioning submodule in the present invention.

[0055] Figure 4 It is a structural schematic diagram of the active support module in the present invention.

[0056] Figure 5 It is a schematic diagram of the structure of the execution device in the present invention.

[0057] Figure 6 It is a schematic structural diagram of the supporting device in the present invention.

[0058] Figure 7 It is a schematic diagram of the structure of the driving device in the present invention.

[0059] Figure 8 It is a structural schematic diagram of the deformation monitoring module in the present invention.

[0060] Fig. 9 Schematic diagram of a thin-walled annular part.

[0061] Fig.10 It is a schematic diagram of the state when the thin-walled annular part is clamped and supported by using the present invention.

[0062] Fig.11 The figure is a schematic diagram of the use process of the active control device for elastic deformation in processing thin-walled annular parts according to the present invention.

[0063] Fig.12 It is a schematic diagram of the signal transmission method involved in the active control device for elastic deformation processing of thin-walled annular parts of the present invention.

[0064] Fig.13 This is an example of the present invention in which multiple active support modules are used in combination.

[0065] Description of reference numerals:

[0066] 100-clamping module; 101-clamping submodule; 1011-clamping base plate; 1012-double-headed flange support column; 1013-clamping cover plate; 1014-bolt group; 102-positioning submodule; 1021-first positioning ring; 1022-second positioning ring; 1023-third positioning ring; 1024-fourth positioning ring;

[0067] 200-active support module; 201-pneumatic actuator; 2011-support base; 2012-first support device; 2013-second support device; 2014-third support device; 2015-fourth support device; 20121-cylinder; 20122-sensor connecting plate; 20123-pressure sensor; 20124-support head connecting plate; 20125-inner surface support head; 20126-clamping bolt; 202-pneumatic drive device; 2021-first drive group; 2022-second drive group; 2023-third drive group; 2024-fourth drive group; 20211-solenoid valve; 20212-electric proportional valve; 20213-signal converter;

[0068] 300-deformation monitoring module; 301-first deformation monitoring device; 302-second deformation monitoring device; 303-third deformation monitoring device; 304-fourth deformation monitoring device; 3011-eddy current displacement sensor; 3012-displacement sensor mounting plate; 3013-front box;

[0069] 400-control module;

[0070] 500-Thin-walled ring parts. DETAILED DESCRIPTION

[0071] The present invention will be further described below in conjunction with the accompanying drawings.

[0072] like Figure 1 As shown, the thin-walled annular component machining elastic deformation active control device provided by the present invention includes a clamping module 100, an active supporting module 200, a deformation monitoring module 300 and a regulating module 400.

[0073] The clamping module 100 is used to perform circumferential positioning and axial clamping of the processed thin-walled annular part;

[0074] The active support module 200 is used to provide adjustable, multiple independent, equal lateral support forces to the inner surface of the thin-walled annular component; the active support module 200 has a support force detection function and can send the support force it provides to the control module;

[0075] The deformation monitoring module 300 is used to monitor the deformation of the thin-walled annular part during the processing;

[0076] The control module 400 is used to control the operation of the active support module 200 and the deformation monitoring module 300, and to process the support force data detected by the active support module 200 and the elastic deformation data detected by the deformation monitoring module 300, so as to obtain the deformation field and control parameters of the thin-walled annular part, and then issue control instructions to the active support module 200.

[0077] The following is a detailed description of each part.

[0078] 1. Clamping module

[0079] The clamping module 100 includes a clamping submodule 101 and a positioning submodule 102 .

[0080] like Figure 2 As shown, the clamping submodule 101 is used to realize axial clamping of thin-walled annular parts; the clamping submodule 101 includes a clamping base plate 1011, a double-headed flange support column 1012 and a clamping cover plate 1013 connected in sequence from bottom to top, and the clamping base plate 1011 and the double-headed flange support column 1012, and the clamping cover plate 1013 and the double-headed flange support column 1012 are connected and fastened by bolt groups 1014. The height of the double-headed flange support column 1012 is determined according to the height of the thin-walled annular part to be processed, and the shapes of the clamping base plate 1011 and the clamping cover plate 1013 are not limited, as long as the processed thin-walled annular part can be clamped between the clamping base plate 1011 and the clamping base plate 1013. The upper surface of the clamping base plate 1011 is also provided with a plurality of arc holes 10111, a plurality of strip grooves 10112 and a plurality of mounting holes 10113; the arc holes 10111 and the strip grooves 10112 are used for discharging coolant during the processing to avoid the accumulation of coolant and damage to the components of the device; the mounting holes 10113 are used for installing the solenoid valve and the electric proportional valve in the positioning submodule and the active support module 200, wherein there are multiple groups of mounting holes for installing the positioning submodule, and each group can be distributed on circles of different sizes to facilitate the adjustment of the positioning dimensions of the positioning submodule.

[0081] like Figure 3As shown, the positioning submodule 102 is arranged on the upper end surface of the clamping base plate 1011, and is used to cooperate with the inner profile of the thin-walled ring part to realize the positioning of the thin-walled ring part; the positioning submodule 102 includes a first positioning ring 1021, a second positioning ring 1022, a third positioning ring 1023 and a fourth positioning ring 1024, each of which has two countersunk bolt through holes. The first positioning ring 1021, the second positioning ring 1022, the third positioning ring 1023 and the fourth positioning ring 1024 can be fixedly installed on the upper end surface of the clamping base plate 101 by inserting bolts into the countersunk bolt through holes, and the first positioning ring 1021, the second positioning ring 1022, and the third positioning ring 1023 are evenly distributed along the same circumference, and their side walls are all adapted to the inner wall profile of the processed thin-walled ring part. Since the clamping base plate 1011 is provided with multiple groups of mounting holes for mounting the positioning submodule, the size adjustment of the circumference formed by the four positioning rings can be realized, thereby meeting the positioning requirements for thin-walled ring parts of different diameters. In addition, it should be noted that this embodiment is an exemplary description based on four positioning rings. In other embodiments, the number of positioning rings can be appropriately adjusted according to the inner surface size of the thin-walled ring part being processed. The larger the diameter of the thin-walled ring part, the more positioning rings are required.

[0082] 2. Active support module

[0083] like Figure 4 As shown, the active support module 200 includes a pneumatic actuator 201 and a pneumatic drive device 202 disposed on the clamping base plate 1011. The pneumatic actuator 201 is used to move horizontally under the drive of the pneumatic drive device 202 to support the inner wall of the thin-walled annular member and provide support force to the inner wall of the thin-walled annular member.

[0084] like Figure 5 As shown, the pneumatic actuator 201 includes a support base 2011, a first support device 2012, a second support device 2013, a third support device 2014 and a fourth support device 2015. The legs of the support base 2011 are fixedly mounted on the clamping base plate 1011, and the table of the support base 2011 is used to support and install the first support device 2012, the second support device 2013, the third support device 2014 and the fourth support device 2015, and the first support device 2012, the second support device 2013, the third support device 2014 and the fourth support device 2015 are evenly distributed along the same circumference. Similarly, this embodiment is an exemplary description with four support devices. In other embodiments, the number of support devices can be appropriately adjusted according to the inner profile size of the thin-walled annular part to be processed. The larger the diameter of the thin-walled annular part, the more support devices are required.

[0085] The first supporting device 2012 , the second supporting device 2013 , the third supporting device 2014 and the fourth supporting device 2015 have the same structure, and only the structure of the first supporting device 2012 is taken as an example for description.

[0086] like Figure 6 As shown, the first supporting device 2012 includes a cylinder 20121, a sensor connecting plate 20122, a pressure sensor 20123, a supporting head connecting plate 20124 and an inner surface supporting head 20125, and a clamping bolt 20126 which are connected in sequence.

[0087] There are multiple countersunk bolt holes on the cylinder body of the cylinder 20121, and corresponding threaded holes are provided on the support base 2011. By installing bolts into the countersunk bolt holes, the cylinder 20121 can be fixedly installed on the table top of the support base 2011.

[0088] A through hole is provided on the push rod end face of the cylinder 20121, and a corresponding countersunk bolt hole is provided on the sensor connecting plate 20122. By inserting a bolt into the countersunk bolt hole, the sensor connecting plate 20122 can be fixedly connected to the push rod of the cylinder 20121.

[0089] The bottom of the pressure sensor 20123 is provided with a threaded hole, and the sensor connecting plate 20122 is provided with a countersunk bolt hole corresponding thereto, and the pressure sensor 20123 can be fixedly connected to the sensor connecting plate 20122 by inserting a bolt into the countersunk bolt hole. At the same time, a through hole is also provided near the edge of the sensor connecting plate 20122, and a countersunk threaded hole corresponding thereto is provided on the support head connecting plate 20124, and the pressure sensor 20123 can be arranged between the support head connecting plate 20124 and the sensor connecting plate 20122 through this group of corresponding holes and by using the clamping bolt 20126, and the pressure sensor 20123 can be limited in a specified direction and the application of pre-tightening force can be achieved by adjusting the clamping bolt 20126.

[0090] One end of the inner surface support head 20125 is a plane, and the other end is an arc surface that matches the inner wall of the thin-walled annular part being processed; a countersunk bolt hole is provided on the plane of the inner surface support head 20125, and a corresponding threaded hole is provided on the support head connecting plate 20124. By installing a bolt in the countersunk bolt hole, the inner surface support head 20125 can be fixedly connected to the support head connecting plate 20124.

[0091] like Figure 7 As shown, the pneumatic drive device 202 includes a first drive group 2021 , a second drive group 2022 , a third drive group 2023 and a fourth drive group 2024 which are arranged on the clamping base plate 1011 .

[0092] The first drive group 2021 , the second drive group 2022 , the third drive group 2023 and the fourth drive group 2024 have the same structure, and only the structure of the first drive group 2021 is taken as an example for description.

[0093] The first driving group 2021 includes a solenoid valve 20211, an electrical proportional valve 20212 and a signal converter 20213 arranged on the clamping base plate 1011. The solenoid valve 20211 and the electrical proportional valve 20212 are both connected to the cylinders of the supporting devices in the pneumatic actuator 201. The electrical proportional valve 20212 is used to adjust the pressure of the pressurized gas provided by the gas source to a specified air pressure, and then transmit the gas of the specified air pressure to the cylinders of the supporting devices in the pneumatic actuator 201 through the solenoid valve 20211. The signal converter 20213 is connected to the pressure sensor of each supporting device in the pneumatic actuator 201, and is used to convert the electrical signal output by the pressure sensor into a signal recognizable by the PLC in the control module 400, and transmit it to the PLC and the host computer for data processing and control.

[0094] There is no direct signal transmission between the electric proportional valve 20212, the solenoid valve 20211 and the signal converter 20213. They are controlled by the PLC in the control module 400 to achieve control coordination, which will be described in detail later when the control module 400 is introduced.

[0095] It should be specially noted here that the pneumatic actuator 201 and the pneumatic drive device 202 in the active support module 200 can be replaced by an electric / hydraulic actuator and an electric / hydraulic drive device respectively, as long as the inner surface of the thin-walled annular part can be supported with controllable force. Correspondingly, other components that need to cooperate therewith can be adaptively adjusted. The specific adaptive adjustment is a conventional technical means in the mechanical field and will not be elaborated here.

[0096] In addition, for a thin-walled annular component with a small axial dimension, the active support module 200 in the present invention is one, which can meet the radial support requirements when used alone, such as the thin-walled annular component and the active support module 200 of the present embodiment; however, when the axial dimension of the thin-walled annular component is large, there can be multiple active support modules 200 in the present invention, and these multiple active support modules 200 are arranged along the axial direction. For example, two active support modules 200 arranged up and down can be used to radially support the upper part and the middle and lower part of the thin-walled annular component respectively, such as Fig.13 As shown; three active support modules 200 arranged up and down can also be used to radially support the upper, middle and lower parts of the thin-walled annular member respectively. When multiple active support modules are used, the active support module of the upper level can be fixed on the table of the support base of the active support module of the lower level through the support base, and its support base can also be fixedly connected to the flange support column in the clamping module to fix it.

[0097] 3. Deformation Monitoring Module

[0098] like Figure 8 As shown, the deformation monitoring module 300 is used to monitor the elastic deformation of the thin-walled annular part in real time during the processing, and includes a first deformation monitoring device 301, a second deformation monitoring device 302, a third deformation monitoring device 303 and a fourth deformation monitoring device 304 arranged on the table of the support base 2011.

[0099] The first deformation monitoring device 301 , the second deformation monitoring device 302 , the third deformation monitoring device 303 and the fourth deformation monitoring device 304 have the same structure, and only the structure of the first deformation monitoring device 301 is taken as an example for description.

[0100] The first deformation monitoring device 301 includes an eddy current displacement sensor 3011 , a displacement sensor mounting plate 3012 and a front box 3013 .

[0101] The displacement sensor mounting plate 3012 is used to mount the eddy current displacement sensor 3011 on the table of the support base 2011; the eddy current displacement sensor 3011 is used to detect the elastic deformation of the inner surface of the processed thin-walled annular part; the number of eddy current displacement sensors 3011 in the deformation monitoring module 300 is consistent with the number of support devices in the active support module 200, all eddy current displacement sensors 3011 are arranged in a circular array along the circumference of the thin-walled annular part, and an eddy current displacement sensor 3011 is arranged between every two support devices, so that four characteristic points on the inner surface of the processed thin-walled annular part can be monitored at the same time. The eddy current displacement sensor 3011 can also be replaced by an inductive displacement sensor, a capacitive displacement sensor, a laser displacement sensor, an LVDT sensor, etc. The front box 3013 is used in conjunction with the eddy current displacement sensor 3011 to provide the power required by the eddy current displacement sensor 3011, and to amplify, detect and filter the signal output by the eddy current displacement sensor 3011; the front box 3013 is an existing mature product.

[0102] In this embodiment, the displacement sensor mounting plate 3012 is an L-shaped plate, the bottom plate of which is fixedly mounted on the table top of the support base 2011 by bolts, and the side plates thereof are processed with threaded holes for mounting the eddy current displacement sensor 3011 .

[0103] The outer surface of the eddy current displacement sensor 3011 is a threaded structure. The eddy current displacement sensor 3011 is screwed into the threaded hole on the side plate of the displacement sensor mounting plate 3012 and connected with a nut and the measuring range is adjusted.

[0104] The front box 3013 is fixedly mounted on the table top of the support base 2011 by means of bolts.

[0105] 4. Control Module

[0106] The control module 400 is used to control the operation of the active support module 200 and the deformation monitoring module 300, and to process the support force data detected by the active support module 200 and the elastic deformation data detected by the deformation monitoring module 300, so as to obtain the deformation field of the thin-walled annular part and the support force control parameters of the active support module, and then issue control instructions to the active support module 200. The control module 400 includes an industrial computer, a PLC, a digital-to-analog conversion module, a data acquisition module, a power supply and an air compressor, wherein the industrial computer is pre-installed with s elastic deformation prediction models, which correspond one by one to each process of the thin-walled annular parts, and are used to predict the elastic deformation of each processing node in each process after processing is completed; for any process, the experimentally calibrated milling force, the preset target support force, the boundary conditions, the material properties, the contact conditions and the elastic deformation extraction point are input into the corresponding elastic deformation prediction model, and the predicted value of the elastic deformation at the elastic deformation extraction point after processing of each processing node in the process is obtained; the preset target support force is determined by the support force control curve of each processing node, and the support force control curve is a curve showing the change of the support force with the processing node (or time); the support force control curve of each processing node and the method for establishing the elastic deformation prediction model will be described in detail in the following elastic deformation active control method. The PLC is pre-set with the support force control curve of each processing node, which is the basis for setting and adjusting the support force. In addition, the voltage signal 0-10V is set in the PLC to correspond to the air pressure value 0-0.5Mpa, and the 0-10V voltage signal is set in the analog conversion module to correspond to the 0-20000 digital signal. At this time, the relationship between the air pressure value setting and the analog signal can be expressed as follows: The conversion relationship between analog signal and digital signal can be expressed as Where V is the analog signal and D is the digital signal.

[0107] The functions of each part are as follows:

[0108] Before the machining process starts, the industrial computer sends a first control instruction to the PLC, and the PLC cooperates with the digital-to-analog conversion module to send corresponding analog signals to all the electrical proportional valves 20212 of the pneumatic drive device 202 in the active support module 200 according to the received first control instruction and based on the support force control curve preset therein, so as to set the initial air source pressure; then, the PLC sends digital signals to all the solenoid valves 20211 of the pneumatic drive device 202 in the active support module 200 through the IO port to control the synchronous extension and retraction of all the cylinders 20121 of the pneumatic actuator 201 in the active support module 200, so as to set the initial state of the active support module 200, and then start the normal milling program;

[0109] Then, during the processing, the PLC sends a first request instruction to all the pressure sensors 20123 of the pneumatic actuator in the active support module 200, and the data acquisition module reads the monitoring value of each pressure sensor 20123 in the active support module 200 to the PLC, and the PLC compares the support force monitoring value with the support force set value determined by the support force control curve. If there is inconsistency and it needs to be adjusted to the set value, the PLC uses the PID algorithm in conjunction with the digital-to-analog conversion module to perform feedback adjustment until the active support module 200 provides the required support force to the thin-walled annular part, thereby realizing active control of the support force within the process;

[0110] After the current process is completed and before the next process begins, the industrial computer sends a second request instruction to the eddy current displacement sensor 3011 in the deformation monitoring module 300, and the data acquisition module reads the monitoring values ​​of all eddy current displacement sensors 3011 to the industrial computer, and the industrial computer performs data fitting to obtain the actual deformation field of the inner surface of the thin-walled annular part, and then the industrial computer compares the actual deformation field with the predicted deformation field predicted by the elastic deformation prediction model, and calculates the support force compensation required for each processing node in the next process through Hooke's law, and all support devices correspond to the same support force compensation.

[0111] After the current process is finished and before the next process begins, the industrial computer sends a second control instruction to the PLC to adjust the control parameters of the active support module 200. Specifically, the industrial computer determines the required support force based on the support force compensation amount of the next process obtained above and transmits it to the PLC, and then the PLC adjusts the support force based on the relationship between the support force and the air pressure value F s =P·S c Convert the support force to the air pressure value to determine the air pressure value required after compensation (P is the air pressure value, S is the air pressure value). c is the effective area of ​​the cylinder piston, F s The PLC sends an analog signal corresponding to the compensated air pressure value to all the electrical proportional valves 20212 of the pneumatic drive device 202 in the active support module 200 through the digital-to-analog conversion module, thereby realizing adaptive adjustment of the support force. This control method does not require re-clamping of the thin-walled annular parts, ensuring the accuracy and efficiency of processing.

[0112] According to the requirements of the processing procedure, the active support module 200 and the data monitoring module 300 can be regulated by the above control instructions and request instructions during the whole processing process, so as to realize the adaptive control of elastic deformation of thin-walled annular parts milling.

[0113] The monitoring screen of the industrial computer displays the deformation monitoring results and relevant information of each regulated component.

[0114] The power supply is used to supply power to the industrial computer, PLC, displacement sensor 3011, pressure sensor 20123, electric proportional valve 20212 and solenoid valve 20211.

[0115] The air compressor is used to provide an air source to the cylinder 20121 of the active support module 200 .

[0116] Reference Fig.11 The working process and principle of the thin-walled annular component processing elastic deformation active control device of the present invention for thin-walled annular components are as follows:

[0117] Step 1: Install the clamping submodule 101 on the machine tool workbench and fix it, install the positioning submodule 102 and the thin-walled annular part 500 together on the clamping submodule 101, and press the clamping cover plate 1013 of the clamping submodule 101 to complete the clamping of the thin-walled annular part 500;

[0118] Step 2: Turn on the power supply to start the active control device for elastic deformation of thin-walled annular parts processing;

[0119] Step three: Set the initial support force on the industrial computer and control the inner surface support head 20125 of the pneumatic actuator 201 in the active support module 200 to extend to support the inner wall of the thin-walled annular component 500 .

[0120] Step 4: Start processing the designated process. Due to the time-varying characteristics of the cutting force, the support force will fluctuate during processing. In order to provide a stable support force, the support force data is collected through the pressure sensors of each support device in the active support module 200 and the PID algorithm is used for feedback adjustment. At the same time, due to the weak rigidity of the thin-walled annular part 500, the thin-walled annular part will produce different degrees of elastic deformation during the processing. The deformation data of the thin-walled annular part is obtained through the eddy current displacement sensors of each deformation monitoring device in the deformation monitoring module 300, and the deformation field of the current processing process of the workpiece is calculated in conjunction with the control module 400.

[0121] Step 5: After the current process is finished, all the inner surface support heads 20125 of the pneumatic actuator 201 in the active support module 200 are retracted and separated from the inner wall of the thin-walled annular component, and the initial support force required for the next process is compensated according to the deformation field of this process, and then all the inner surface support heads 20125 of the pneumatic actuator 201 in the active support module 200 are extended again to support the inner wall of the thin-walled annular component 500;

[0122] Step 6: Repeat steps 3 and 5 until all processes are completed.

[0123] In addition to the above-mentioned thin-walled annular component processing elastic deformation active control device, the present invention also provides a thin-walled annular component processing elastic deformation active control method, the specific steps are as follows:

[0124] Step 1: Obtain the deformation field and stiffness field after each process is completed, as well as the support force control curve in each process;

[0125] Step 1.1 Create CAD models after each process is completed and import these CAD models into finite element simulation software;

[0126] Step 1.2: Determine the range of fixed support force corresponding to each process according to the milling force in the process obtained by experimental calibration;

[0127] Step 1.3 For each process, within the range of the corresponding fixed support force, k fixed support force values ​​are selected according to the set step length, and a group of first elastic deformation prediction models are established for it based on the CAD model after the process is completed and through finite element simulation. The group of first elastic deformation prediction models includes k models, which correspond to the k fixed support force values ​​one by one; s processes need to construct s groups of first elastic deformation prediction models; after the first elastic deformation prediction model is established, the parameters of the first elastic deformation prediction model are set, including milling force, support force, boundary conditions, material properties, and contact conditions, wherein the milling force is obtained by experimental calibration, and the support force is the k fixed support force values ​​selected according to the set step length;

[0128] Step 1.4: For each process, a milling path is first set, which includes n processing nodes. Since each processing node corresponds to k first elastic deformation prediction models, k sets of elastic deformation data can be obtained for the n processing nodes of each process after simulation.

[0129] Step 1.5: For each process, a data set is constructed with k groups of elastic deformation data and corresponding fixed support force values ​​corresponding to each processing node in the process. The functional relationship between the elastic deformation and the support force at each processing node in the process is solved by the numerical fitting method. The elastic deformation is constrained within the tolerance range of the design requirements by setting constraints, and the functional relationship is solved to obtain the target support force of each processing node in the process.

[0130] Step 1.6 For each process, perform function interpolation and fitting on the target support force of each processing node in the process to obtain the support force control curve of each processing node in the process, which is used as the basis for adjusting the support force in each process; a total of s support force control curves are obtained for s processes.

[0131] Step 1.7 establishes a second elastic deformation prediction model for each process through finite element simulation, and sets the parameters of the elastic deformation prediction model, including milling force, support force, boundary conditions, material properties, and contact conditions; among them, the milling force is still the milling force calibrated by the experiment, and the support force is determined according to the support force control curve of each processing node of the process; a total of s second elastic deformation prediction models need to be established for s processes.

[0132] Step 1.8 For each process, first set a milling path, which includes n processing nodes. After simulation, the elastic deformation data of the n processing nodes in the process after completion can be obtained. Each processing node corresponds to an elastic deformation data; the elastic deformation data is arranged according to the position of the processing node, and the deformation field of the workpiece after the process is completed can be obtained.

[0133] Step 1.9 calculates the stiffness field of the workpiece according to the deformation field of the workpiece after each processing step is completed.

[0134] Step 2: In the current processing step, based on the support force control curve of each processing node of the process obtained in step 1.6, the support force provided by all support devices used to support the inner wall of the thin-walled annular part is adjusted within the process by adopting a closed-loop feedback control method;

[0135] Step 3: After the current process is completed, obtain the support force compensation amount of the next process;

[0136] Step 3.1: select z feature points in the rigid weak area on the inner surface of the thin-walled annular part, and set an elastic deformation detection device at each feature point, and use these elastic deformation monitoring devices to obtain the measured data of the elastic deformation at the z feature points.

[0137] Step 3.2 sets z elastic deformation extraction points corresponding to the z feature points on the second elastic deformation prediction model, and after simulation, the prediction data of the elastic deformation at the z feature points can be obtained.

[0138] Step 3.3 After the current process is completed, by comparing the measured data of elastic deformation at z feature points with the predicted data, the elastic deformation prediction error can be obtained, and then the support force compensation amount can be obtained. This support force compensation amount is used to compensate the support force preset value of each processing node in the next process respectively. The support force preset value is a value determined according to the support force control curve.

[0139] The method for obtaining the support force compensation is:

[0140] In any current process, the actual cutting depth of the workpiece can be expressed as de,i=dp,i+ei, where d e,iand dp,i are the actual cutting depth and designed cutting depth in the process respectively, and ei is the processing error of each processing position. The above processing error ei will accumulate as the process progresses, and eventually lead to the workpiece out of tolerance. During the processing, the influence of the support force and the milling force on the deformation of the workpiece can be regarded as the superposition of deformation in two directions. Therefore, in order to offset the deformation, it is necessary to compensate it by changing the support force in the next process. The support force compensation amount is ΔF s =K G ·e i , where K G is the workpiece stiffness field obtained in step 1 using the second elastic deformation prediction model.

[0141] Step 4: Superimpose the support force compensation amount of the next process determined in step 3 and the support force preset value corresponding to each processing node in the next process on the support force control curve, so as to obtain the actual support force required for each processing node in the next process, and use the actual support force as the support force provided by all support devices for supporting the inner wall of the thin-walled annular part.

[0142] Step 5: Repeat steps 2-4 until all processes are completed.

Claims

1. An active control device for elastic deformation of thin-walled annular parts, characterized in that: It includes a clamping module, an active support module, a deformation monitoring module and a control module; The clamping module is used to perform circumferential positioning and axial clamping of the processed thin-walled annular parts; The active support module is used to provide adjustable, multiple independent, equal radial support forces to the inner surface of the thin-walled annular part; the active support module has a support force detection function and can send the support force it provides to the control module; The deformation monitoring module is used to monitor the elastic deformation of thin-walled annular parts during processing; The control module is used to control the operation of the active support module and the deformation monitoring module. The control module also has preset elastic deformation prediction models and support force control curves for each processing node. The control module uses closed-loop feedback control within the process to adjust the support force provided by the active support module based on the support force data detected by the active support module and the support force control curve; it can also process the support force data detected by the active support module and the elastic deformation data detected by the deformation monitoring module before the start of the next process, so as to obtain the actual deformation field of the thin-walled annular part in the previous process, and compare the actual deformation field with the deformation field of the previous process predicted by the elastic deformation prediction model to obtain the support force compensation amount of the next process, and issue a support force control instruction to the active support module before the start of the next process based on the support force compensation amount and the support force control curve, so as to realize support force control between processes.

2. The active control device for elastic deformation of thin-walled annular parts according to claim 1, characterized in that: The clamping module includes a clamping submodule and a positioning submodule; the clamping submodule includes a clamping base plate, a double-headed flange support column and a clamping cover plate connected in sequence from bottom to top, and the thin-walled annular part is clamped by the clamping base plate and the clamping cover plate; the positioning submodule includes at least three positioning rings arranged on the clamping base plate and distributed along the same circumference, and the outer wall of the positioning ring is adapted to the inner wall profile of the thin-walled annular part.

3. The active control device for elastic deformation of thin-walled annular parts according to claim 2, characterized in that: The upper surface of the clamping base plate is provided with a plurality of arc holes, a plurality of strip grooves and a plurality of mounting holes; the arc holes and the strip grooves are used for discharging coolant during processing; the mounting holes are used for installing the positioning submodule; the mounting holes are provided in multiple groups, and each group is distributed on a circumference of different sizes so as to adjust the positioning dimensions of the positioning submodule.

4. The active control device for elastic deformation of thin-walled annular parts according to any one of claims 1 to 3, characterized in that: The active support module includes a driving device arranged on the clamping base plate and an actuator with a support force detection function; there are m actuators evenly distributed along the same circumference, and each of the actuators can independently move in the radial direction under the drive of the driving device to support the inner wall of the thin-walled annular member; the driving device is connected to the control module, and its operation is controlled by the control module; m≥3； The actuator is a pneumatic actuator, an electric actuator or a hydraulic actuator, and correspondingly, the drive device is a pneumatic drive device, an electric drive device or a hydraulic drive device.

5. The active control device for elastic deformation of thin-walled annular parts according to claim 4, characterized in that: The actuator is a pneumatic actuator, comprising a support base and m support devices; the legs of the support base are fixedly mounted on the clamping base plate, and the table of the support base is used to support and mount the m support devices; A single support device includes a cylinder, a sensor connecting plate, a pressure sensor, a support head connecting plate and an inner surface support head connected in sequence; the cylinder is installed on the table of the support base, the sensor connecting plate is fixedly connected to the push rod of the cylinder; the sensor connecting plate is connected to the support head connecting plate by clamping bolts; The driving device is a pneumatic driving device, including m driving groups arranged on the clamping base plate; a single driving group includes a solenoid valve, an electric proportional valve and a signal converter arranged on the clamping base plate; the solenoid valve and the electric proportional valve are connected to the cylinder, the electric proportional valve is used to adjust the gas pressure entering the cylinder to a specified air pressure, and the solenoid valve is used to transmit the gas of the specified air pressure to the cylinder; the signal converter is connected to the pressure sensor, and is used to convert the electrical signal output by the pressure sensor into a signal recognizable by the control module.

6. The active control device for elastic deformation of thin-walled annular parts according to claim 5, characterized in that: There are one or more active support modules; when there are multiple active support modules, they are arranged in sequence along the axial direction and used in combination to support different axial regions of the thin-walled annular component.

7. The active control device for elastic deformation of thin-walled annular parts according to claim 6, characterized in that: The deformation monitoring module comprises m deformation monitoring devices arranged on the table surface of the support base; the m deformation monitoring devices are evenly distributed along the circumference, and a deformation monitoring device is arranged between every two support devices; a single deformation monitoring device comprises a displacement sensor and a front box; The displacement sensor is installed on the table of the support base through the displacement sensor mounting plate. The displacement sensor is used to detect the elastic deformation of the inner surface of the thin-walled annular part; the front box is used to provide the power required by the displacement sensor and to amplify, detect and filter the signal output by the displacement sensor.

8. The active control device for elastic deformation of thin-walled annular parts according to claim 7, characterized in that: The control module includes an industrial computer, a PLC, a digital-to-analog conversion module, a data acquisition module, a power supply and an air compressor; the elastic deformation prediction model is preset on the industrial computer; the support force control curve of each processing node is preset in the PLC, and the corresponding relationship between the voltage signal and the air pressure value is set in the PLC; Before the processing procedure starts, the industrial computer sends a first control instruction to the PLC, and the PLC cooperates with the digital-to-analog conversion module to send corresponding analog signals to all the electrical proportional valves of the pneumatic drive device in the active support module according to the received first control instruction and based on the support force control curve, so as to set the initial air source pressure; then, the PLC sends digital signals to all the solenoid valves of the pneumatic drive device in the active support module through the IO port to control the synchronous extension and retraction of all the cylinders of the pneumatic actuator in the active support module, so as to set the initial state of the active support module; Then, the PLC sends a first request instruction to all the pressure sensors of the pneumatic actuators in the active support module. The data acquisition module reads the monitoring values ​​of each pressure sensor in the active support module to the PLC, and the PLC compares the support force monitoring value with the support force setting value. If there is inconsistency and it needs to be adjusted to the setting value, the PLC uses the PID algorithm in conjunction with the digital-to-analog conversion module to perform feedback adjustment until the active support module provides the required support force to the thin-walled annular part, and then starts the normal milling program; During the processing, the industrial computer sends a second request instruction to the displacement sensor in the deformation monitoring module. The data acquisition module reads the monitoring values ​​of all displacement sensors to the industrial computer, and the industrial computer performs data fitting to obtain the actual deformation field of the inner surface of the thin-walled annular part. The industrial computer then compares the actual deformation field with the workpiece deformation field predicted by the elastic deformation prediction model, and calculates the support force compensation required for the next process through Hooke's law. All support devices correspond to the same support force compensation. Between processes, the industrial computer determines the required supporting force based on the supporting force compensation amount of the next process obtained previously and transmits it to the PLC. The PLC then converts the supporting force into air pressure value to determine the air pressure value required after supporting force compensation. The PLC sends an analog signal corresponding to the compensated air pressure value to all electrical proportional valves of the pneumatic drive device in the active support module through the digital-to-analog conversion module, thereby realizing adaptive adjustment of the supporting force.

9. A method for actively controlling elastic deformation of thin-walled annular parts during machining, characterized in that: The following steps are involved: Step 1: Obtain the deformation field and stiffness field after each process is completed, as well as the support force control curve in each process; Step 1.1 Create a CAD model after each process and import it into the finite element simulation software; Step 1.2: Determine the range of fixed support force corresponding to each process according to the milling force in the process calibrated by the experiment; Step 1.3 For each process, within the range of the corresponding fixed support force, k fixed support force values ​​are selected according to the set step length, and a group of first elastic deformation prediction models are established for it based on the CAD model after the process is completed and through finite element simulation. The group of first elastic deformation prediction models includes k models, which correspond to k fixed support force values ​​one by one; s processes need to construct s groups of first elastic deformation prediction models; after the model is established, set the model parameters, including milling force, support force, boundary conditions, material properties, and contact conditions, wherein the milling force is obtained by experimental calibration, and the support force is the k fixed support force values ​​selected according to the set step length; Step 1.4: For each process, a milling path is set, and the milling path includes n processing nodes. After simulation, k sets of elastic deformation data can be obtained for the n processing nodes of each process. Step 1.5: For each process, a data set is constructed with k groups of elastic deformation data and corresponding fixed support force values ​​corresponding to each processing node in the process, and the functional relationship between the elastic deformation and the support force at each processing node in the process is solved by the numerical fitting method. The elastic deformation is constrained within the tolerance range of the design requirements by setting constraint conditions, and the functional relationship is solved to obtain the target support force of each processing node in the process; Step 1.6 For each process, perform function interpolation and fitting on the target support force of each processing node in the process to obtain the support force control curve of each processing node in the process; a total of s support force control curves are obtained for s processes; Step 1.7: Establish a second elastic deformation prediction model for each process through finite element simulation, and set the parameters of the elastic deformation prediction model, including milling force, support force, boundary conditions, material properties, and contact conditions; the milling force is still the milling force calibrated by the experiment, and the support force is determined according to the support force control curve of each processing node of the process; a total of s second elastic deformation prediction models need to be established for s processes; Step 1.8 For each process, a milling path is first set, and the milling path includes n processing nodes. After simulation, the elastic deformation data of the n processing nodes in the process after processing can be obtained. Each processing node corresponds to an elastic deformation data; the elastic deformation data is arranged according to the position of the processing node, and the deformation field of the workpiece after the process is completed can be obtained; Step 1.9 calculates the stiffness field of the workpiece according to the deformation field of the workpiece after each process is completed; Step 2: In the current processing step, based on the support force control curve of each processing node of the process obtained in step 1.6, the support force provided by all support devices used to support the inner wall of the thin-walled annular part is adjusted within the process by adopting a closed-loop feedback control method; Step 3: After the current process is completed, obtain the support force compensation amount of the next process; Step 3.1: select z characteristic points in the rigid weak area on the inner surface of the thin-walled annular component, and set an elastic deformation detection device at each characteristic point, and use these elastic deformation monitoring devices to obtain measured data of elastic deformation at the z characteristic points; Step 3.2: setting z elastic deformation extraction points corresponding to the z feature points on the second elastic deformation prediction model, and obtaining the prediction data of elastic deformation at the z feature points after simulation; Step 3.3 After the current process is completed, the measured data of elastic deformation at z feature points are compared with the predicted data to obtain the elastic deformation prediction error, and then the support force compensation amount is obtained. The support force compensation amount is used to compensate the support force preset value of each processing node in the next process respectively. The support force preset value is a value determined according to the support force control curve; Step 4: The support force compensation amount of the next process determined in step 3 is respectively superimposed with the support force preset value corresponding to each processing node in the next process on the support force control curve, that is, the actual support force required by each processing node in the next process is obtained, and the actual support force is used as the support force provided by all support devices for supporting the inner wall of the thin-walled annular part; Step 5: Repeat steps 2-4 until all processes are completed.

10. The method for actively controlling elastic deformation of thin-walled annular parts according to claim 9, characterized in that: The method for obtaining the support force compensation is: In any current process, the actual cutting depth of the workpiece can be expressed as de,i=dp,i+ei, where d e,i and dp,i are the actual cutting depth and designed cutting depth in the process, respectively, and ei is the machining error of each machining position; The support force compensation is ΔF s =K G ·e i , where K G is the workpiece stiffness field obtained in step 1 using the second elastic deformation prediction model.

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