Aviation part drilling machine and automatic drilling control method thereof

Abstract

The invention discloses an aeronautical part drilling machine and an automatic control drilling method thereof.The aeronautical part drilling machine comprises drilling equipment, a vibration sensor, a control system, a gas control valve and an air compression station, the drilling equipment is a feeding drill provided with a drill bit, the feeding drill is connected with the air compression station through an air pipe, and the gas control valve is arranged on the air pipe; a vibration sensor is arranged on the side face of the feeding drill, the vibration sensor and the gas control valve are electrically connected with a control system, the control system monitors the cutting state in real time through the vibration sensor and automatically adjusts the opening degree of the gas control valve to achieve pressure control when a vibration characteristic value exceeds a preset range, and the pressure is controlled by analyzing a cutting vibration signal in real time. The gas pressure and the feeding speed are dynamically adjusted, and the precision control problem in aeronautical material large hole machining is solved. Experiments show that by means of the method, the superior product rate can be increased to 95%, and the processing efficiency is improved by 30%.

Description

Technical Field

[0001] This invention belongs to the field of machining technology, specifically relating to an aerospace parts drilling machine and its automatic control drilling method. Background Technology

[0002] When machining large holes in the wing and fuselage of aircraft, especially high-precision holes (H8 grade) with a diameter of Φ≥16mm, there are cutting control challenges due to the material's crystallization characteristics.

[0003] In the existing technology, the following defects exist when the 102 drilling rig is used to machine large holes in aerospace aluminum alloy fuselages: 1. Uneven grain orientation of the material causes fluctuations in cutting force, which is difficult to compensate for in real time by traditional PID control; 2. Manual adjustment of air pressure (0.4-0.6MPa) and feed speed (0.1-0.3mm / r) relies on operator experience, resulting in a yield rate of only 68%-72%. 3. When vibration is abnormal (frequency > 500Hz or amplitude > 0.2mm), there is a lack of rapid response mechanism, which can easily lead to out-of-tolerance hole diameter and tool breakage. Summary of the Invention

[0004] To overcome the aforementioned shortcomings, the inventors of this invention, through long-term exploration, experimentation, and continuous innovation, have proposed an aerospace parts drilling rig. This rig solves the precision control problem in large-hole machining of aerospace materials by dynamically adjusting gas pressure and feed rate through real-time analysis of cutting vibration signals. Experiments show that this method can increase the yield rate to 95% and improve processing efficiency by 30%.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is to provide an aerospace parts drilling rig. It includes drilling equipment, a vibration sensor, a control system, a gas control valve, and an air compressor station. The drilling equipment is a feed drill with a drill bit installed. The feed drill is connected to the air compressor station via an air pipe, on which a gas control valve is installed. A vibration sensor is installed on the side of the feed drill. The vibration sensor, the gas control valve, and the control system are electrically connected. The control system monitors the cutting state in real time through the vibration sensor and automatically adjusts the opening of the gas control valve to achieve pressure control when the vibration characteristic value exceeds a preset range.

[0006] A further preferred embodiment of the aerospace parts drilling rig according to the present invention is as follows: the control system includes a data acquisition unit, a data processing unit, and a control unit. The data acquisition unit is used to acquire data from the vibration sensor and process it by the data processing unit. The data processing unit has a built-in FFT spectrum analysis module to process the signals collected by the vibration sensor in real time. The control unit controls the opening degree of the gas control valve according to the analysis results.

[0007] A further preferred embodiment of the aerospace parts drilling rig according to the present invention is that the vibration sensor has a sampling frequency of 10kHz-50kHz.

[0008] A further preferred embodiment of the aerospace parts drilling rig according to the present invention is that the output pressure stability of the air compressor station is ±1%FS.

[0009] A further preferred embodiment of the aerospace parts drilling rig according to the present invention is that the gas control valve has a response time of <50ms.

[0010] An automatic control drilling method for an aerospace parts drilling rig includes the following steps: S1, parameter setting: the air compressor station sets the pressure and pressurizes to reach the preset pressure; the initial air pressure is set to obtain the drilling pressure; the threshold values ​​for the vibration frequency and amplitude of the control system are set; S2, the drill bit moves downward at the drilling start position and begins drilling with the downpressure obtained according to the set initial air pressure; at this time, the vibration sensor detects vibration data; S3, the control system receives and processes the vibration data, and determines whether the vibration data exceeds the set vibration frequency or amplitude threshold. If it does not exceed the threshold, the original initial pressure is maintained; if either data exceeds the threshold, the opening of the gas control valve is controlled to adjust the air pressure; S4, if the vibration frequency and amplitude are detected to return to below the set threshold, the current air pressure is maintained; if they exceed the threshold, the opening of the gas control valve is controlled until the vibration frequency and amplitude return to below the set threshold.

[0011] A further preferred technical solution of the automatic control drilling method for aerospace parts according to the present invention is: updating the control parameters every 0.1s-0.5s to form a closed loop.

[0012] A further preferred technical solution of the automatic control drilling method for aerospace parts according to the present invention is as follows: In step S3, the control system outputs a pulse signal through a fuzzy control algorithm to drive the opening adjustment of the start control valve.

[0013] A further preferred technical solution of the automatic control drilling method for aerospace parts drilling rigs according to the present invention is: by establishing a vibration-pressure nonlinear mapping model, pressure regulation data can be directly obtained from vibration data, thus avoiding the lag of traditional linear control.

[0014] A further preferred technical solution of the automatic control drilling method for aerospace parts according to the present invention is as follows: in steps S3 and S4, the gas control valve opening is adjusted to regulate the gas pressure by adopting a step-down pattern, and the gas pressure decreases by no more than 0.05 MPa each time.

[0015] Compared with the prior art, the technical solution of the present invention has the following advantages / benefits: 1. By analyzing cutting vibration signals in real time and dynamically adjusting gas pressure and feed rate, the precision control problem in large-hole machining of aerospace materials was solved. Experiments show that this method can increase the yield rate to 95% and improve machining efficiency by 30%.

[0016] 2. For the first time, vibration frequency domain characteristics are coupled with air pressure control, which improves the response speed by 8 times compared with manual operation. It can respond quickly to vibration anomalies (frequency > 500Hz or amplitude > 0.2mm) and basically avoid hole diameter deviation and tool breakage.

[0017] 3. Establish a "vibration-air pressure" nonlinear mapping model to avoid the lag of traditional linear control. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a system control block diagram of an aviation parts drilling machine and its automatic control drilling method according to the present invention.

[0020] Figure 2 This is a vibration-air pressure regulation curve of an aviation parts drilling rig and its automatic control drilling method according to the present invention.

[0021] Figure 3 This is a bar chart comparing the machining accuracy of an aerospace parts drilling machine and its automatic control drilling method according to the present invention.

[0022] The markings in the diagram are as follows: 101. Drill bit; 102. Drilling rig; 200. Control system; 201. Vibration sensor; 202. Acquisition unit; 203. Processing unit; 204. Control unit; 205. Gas control valve; 300. Air compressor station. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Therefore, the detailed description of the embodiments of this invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Example 1:

[0025] like Figure 1 As shown, an aerospace parts drilling rig includes a drilling device, a vibration sensor, a control system, a gas control valve, and an air compressor station. The drilling device is a feed drill with a drill bit installed. The feed drill is connected to the air compressor station via an air pipe, on which a gas control valve is installed. A vibration sensor is installed on the side of the feed drill. The vibration sensor, the gas control valve, and the control system are electrically connected. The control system monitors the cutting state in real time through the vibration sensor and automatically adjusts the opening of the gas control valve to achieve pressure control when the vibration characteristic value exceeds a preset range. The pressure is generally reduced in a small gradient, and the pressure can be increased if necessary.

[0026] The control system includes a data acquisition unit, a data processing unit, and a control unit. The data acquisition unit acquires data from the vibration sensor, which is then processed by the data processing unit. The data processing unit has a built-in FFT spectrum analysis module to process the signals collected by the vibration sensor in real time. The control unit controls the opening of the gas control valve based on the analysis results. The control system can be implemented using a PCB board.

[0027] The vibration sensor has a sampling frequency of 10kHz-50kHz. Of course, this is just a rough estimate to meet the sampling accuracy requirements, and it can be modified if necessary.

[0028] The output pressure stability of the air compressor station is ±1%FS. The air compressor station is mainly used to provide compressed air and maintain pressure stability. The final data is determined by the processing accuracy and the pressure accuracy requirements of the drilling rig, which determines the pressure fluctuation requirements of the entire system. Therefore, there are certain requirements for the airtightness of the pressure regulating valve and pipeline.

[0029] The gas control valve has a response time of <50ms. A shorter response time is generally required to improve the quality of the machining. Of course, the decisive factor is the time it takes to reflect the downward pressure of the drill bit. The response time of the gas control valve is only a general requirement. Example 2:

[0030] An automatic control drilling method for an aerospace parts drilling rig includes the following steps: S1, parameter setting: the air compressor station sets the pressure and pressurizes to reach the preset pressure; the initial air pressure is set to obtain the drilling pressure; the threshold values ​​for the vibration frequency and amplitude of the control system are set; S2, the drill bit moves downward at the drilling start position and begins drilling with the downpressure obtained according to the set initial air pressure; at this time, the vibration sensor detects vibration data; S3, the control system receives and processes the vibration data, and determines whether the vibration data exceeds the set vibration frequency or amplitude threshold. If it does not exceed the threshold, the original initial pressure is maintained; if either data exceeds the threshold, the opening of the gas control valve is controlled to adjust the air pressure; S4, if the vibration frequency and amplitude are detected to return to below the set threshold, the current air pressure is maintained; if they exceed the threshold, the opening of the gas control valve is controlled until the vibration frequency and amplitude return to below the set threshold.

[0031] The control parameters are updated every 0.1s-0.5s to form a closed loop. Of course, for machining parts with higher precision requirements, the cycle update time can be shorter. Similarly, for parts with lower precision requirements, the adjustment feedback time can be longer.

[0032] In step S3, the control system outputs a PWM signal through a fuzzy control algorithm to drive the opening adjustment of the gas control valve.

[0033] By establishing a vibration-pressure nonlinear mapping model, pressure regulation data can be obtained directly from vibration data, avoiding the lag of traditional linear control. This mapping model can directly obtain the corresponding pressure control data from vibration data. The model can be established through multiple additional experiments, which can be understood as obtaining the corresponding pressure regulation data from empirical data.

[0034] In steps S3 and S4, the gas control valve opening is adjusted to regulate the gas pressure using a step-down pattern. Each pressure drop is no more than 0.05 MPa. This gradient reduction can be adjusted as needed. For example, if the threshold values ​​of vibration frequency and amplitude are significantly exceeded, the pressure can be reduced proportionally or by a larger margin. Of course, the gas pressure can also be increased if necessary. Example 3:

[0035] Based on Example 2, a 7075-T6 aluminum alloy wing-body joint (Φ18H8) was machined. Adjusting the control threshold to 300Hz > f > 500Hz as the optimal range can achieve better machining results. Initial parameters: air pressure 0.5MPa, feed 0.2mm / r.

[0036] At the 12th second, f=480Hz and A=0.18mm were detected, indicating a risk of being out of range. The system automatically reduced the voltage to 0.45MPa. After 15 seconds, the vibration recovered to f=380Hz and A=0.12mm, which is within an optimal range. These parameters were maintained until the hole machining was completed. Pressure changes were as follows: Figure 2 As shown, key indicators of machining accuracy include, for example... Figure 3 As shown, this includes hole diameter error, hole wall roughness, hole roundness, etc., from... Figure 3 It can be seen that the data obtained from the processing are all superior to the original drilling control method. Example 4:

[0037] Based on Example 2, processing of titanium alloy TC4 material was performed. Adjusting the control threshold to trigger adjustment when f > 550Hz or A ≥ 0.25mm also yielded excellent processing results. It can be seen that the setting of the adjustment threshold is based on experience and is subject to fluctuation; it can be adjusted according to the vibration frequency and amplitude for different processing materials and specific processing parameters.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A drilling rig for aerospace parts, characterized in that, It includes drilling equipment, vibration sensors, a control system, a gas control valve, and an air compressor station. The drilling equipment is a feed drill with a drill bit installed. The feed drill is connected to the air compressor station via an air pipe, and a gas control valve is installed on the air pipe. A vibration sensor is installed on the side of the feed drill. The vibration sensor, the gas control valve, and the control system are electrically connected. The control system monitors the cutting status in real time through the vibration sensor and automatically adjusts the opening of the gas control valve to achieve pressure control when the vibration characteristic value exceeds the preset range.

2. The aerospace parts drilling rig according to claim 1, characterized in that, The control system includes a data acquisition unit, a data processing unit, and a control unit. The data acquisition unit acquires data from the vibration sensor, which is then processed by the data processing unit. The data processing unit has a built-in FFT spectrum analysis module to process the signals collected by the vibration sensor in real time and obtain analysis results. The control unit controls the opening degree of the gas control valve based on the analysis results.

3. The aerospace parts drilling rig according to claim 1, characterized in that, The vibration sensor has a sampling frequency of 10kHz-50kHz.

4. The aerospace parts drilling rig according to claim 1, characterized in that, The output pressure stability of the air compressor station is ±1%FS.

5. The aerospace parts drilling rig according to claim 1, characterized in that, The gas control valve has a response time of <50ms.

6. An automatic control drilling method for aerospace parts drilling rigs, characterized in that, The steps include: S1, parameter setting: the air compressor station sets the pressure and pressurizes to reach the preset pressure; the initial air pressure is set to obtain the drilling pressure; the threshold values ​​for the vibration frequency and amplitude of the control system are set. S2, the drill bit moves downward at the starting position of the borehole and begins drilling by obtaining the downward pressure according to the set initial air pressure. At this time, the vibration sensor detects the vibration data. S3, the control system receives and processes the vibration data and determines whether the vibration data exceeds the set threshold values ​​for vibration frequency or amplitude. If it does not exceed the threshold values, the original initial pressure is maintained. If either data exceeds the threshold values, the opening of the gas control valve is controlled to adjust the air pressure. S4, if the vibration frequency and amplitude are detected to return to below the set threshold values, the current air pressure is maintained. If they exceed the threshold values, the opening of the gas control valve is controlled until the vibration frequency and amplitude return to below the set threshold values.

7. The automatic control drilling method for aerospace parts drilling rig according to claim 6, characterized in that, The control parameters are updated every 0.1-0.3 seconds to form a closed loop.

8. The automatic control drilling method for aerospace parts drilling rig according to claim 6, characterized in that, In step S3, the control system outputs a pulse signal through a fuzzy control algorithm to drive the opening adjustment of the start control valve.

9. The automatic control drilling method for aerospace parts drilling rig according to claim 6, characterized in that, By establishing a vibration-pressure nonlinear mapping model, pressure regulation data can be obtained directly from vibration data, avoiding the lag of traditional linear control.

10. The automatic control drilling method for aerospace parts drilling rig according to claim 6, characterized in that, In steps S3 and S4, the gas control valve opening is adjusted to regulate the gas pressure in a step-down manner, with each pressure drop not exceeding 0.05 MPa.

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