Air pressure load loading control system and method

Abstract

The invention relates to the technical field of airplane structure strength testing, in particular to an air pressure load loading control system and method, and the system comprises a controller, a positive pressure control system and a negative pressure control system. The positive pressure control system comprises a gas source system and n positive pressure control channels; all the positive pressure control channels are respectively communicated and connected with the air source system, and all the positive pressure control channels are respectively communicated and connected with the controller; the negative pressure control system comprises a vacuum pump system and m negative pressure control channels; and all the negative pressure control channels are respectively communicated and connected with the vacuum pump system and are respectively communicated and connected with the controller. According to the technical scheme, only the number of the positive pressure control channels and the number of the negative pressure control channels need to be set according to needs, the pressurizing experiment control requirement of a plurality of test pieces and the pressure pumping experiment control requirement of the plurality of test pieces can be met at the same time, and only the PID closed-loop control technology needs to be integrated in the whole control process. And convenient, safe and reliable intelligent control can be realized through the controller.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft structure strength testing, and in particular to a pneumatic load loading control system and method. Background Art

[0002] Aircraft structural strength testing is an important part of the development and modification of new aircraft at home and abroad. It is one of the prerequisites for determining whether a newly developed aircraft can be tested and the design can be finalized. Through structural strength testing, load calculations and structural analysis can be optimized, the design safety factor can be made reasonable, the structural bearing capacity can be improved or the structural weight can be reduced, and data and basis can be provided for structural modification and improvement. According to the requirements of the structural strength test specifications, in the ground verification test of aircraft structural strength, in order to accurately simulate the actual loading conditions of the aircraft during flight, in addition to applying force loads to the structure, it is also necessary to apply repeated air pressure loads to the aircraft's fuel tanks, air inlets, cockpits, etc. to verify whether the aircraft's structural strength meets the design requirements, and provide a basis for aircraft life determination, design improvements and modifications.

[0003] In traditional aircraft structural strength tests, especially long-cycle full-aircraft fatigue tests, the pressure of the aircraft fuel tank, cabin, and air inlet is often directly charged or pumped to the final target value before the test, and then the force load is applied step by step according to the test spectrum. The test data obtained by this test method has a large deviation from the actual load of the structure during the flight of the aircraft, which affects the aircraft structure stress analysis and guides design improvement and optimization. Summary of the invention

[0004] In order to solve the engineering problem of synchronously coordinating the positive pressure filling and negative pressure extraction of sealed containers such as fuel tanks, cockpits, and air inlets in the aircraft structural strength test, and accurately simulate the actual state of the structure being subjected to repeated air pressure loads during the operation of the aircraft, the patent of this invention provides an air pressure load loading control system and method. The air pressure loading control system uses an electrical proportional valve and an air pressure sensor as the main servo control device, and forms a double closed-loop control system with the controller to achieve precise control of synchronously coordinating the positive pressure filling and negative pressure extraction of multiple test pieces at the same time, improve the control accuracy of the test air pressure load, and truly simulate the structural load of the test piece under different working conditions.

[0005] The above objectives are achieved specifically through the following technical solutions: A pneumatic load loading control system comprises a controller, a positive pressure control system and a negative pressure control system; the positive pressure control system comprises an air source system and n positive pressure control channels, wherein n≥1; all positive pressure control channels are respectively conductively connected to the air source system, and all positive pressure control channels are respectively communicatively connected to the controller; the negative pressure control system comprises a vacuum pump system and m negative pressure control channels, wherein m≥1; all negative pressure control channels are respectively conductively connected to the vacuum pump system, and all negative pressure control channels are respectively communicatively connected to the controller.

[0006] Preferably, the gas source system includes a high-pressure gas source channel, a low-pressure gas source channel and an air distribution row, and the air distribution row is provided with an air inlet and n air outlets corresponding to the positive pressure control channel one by one. The high-pressure gas source channel includes a high-pressure filter, a high-pressure gas exhaust, a high-pressure pressure reducing valve I, a high-pressure pressure reducing valve II and a one-way valve I connected in sequence along the positive direction, and a high-pressure air pressure gauge is connected to the high-pressure gas exhaust. The low-pressure gas source channel includes a low-pressure filter, a low-pressure gas exhaust, an oil mist separator I, a water droplet separator I, an air filter I and a dryer connected in sequence along the positive direction, and a low-pressure air pressure gauge is connected to the low-pressure gas exhaust. The output end of the one-way valve I is connected to the low-pressure gas exhaust, and the output end of the dryer is connected to the air inlet of the air distribution row.

[0007] Preferably, the positive pressure control channel includes a manual stop valve I, a two-position three-way solenoid valve I, an electrical proportional valve I, a forward conducting branch, a safety valve, a normally open solenoid valve I, a pressure gauge and an air pressure sensor connected in sequence along the forward direction, and a reverse conducting branch is connected in parallel at both ends of the forward conducting branch; the two-position three-way solenoid valve I, the electrical proportional valve I, the normally open solenoid valve I and the air pressure sensor are respectively connected to the controller for communication.

[0008] Preferably, the reverse conducting branch is connected with an air filter II, a water droplet separator II, an oil mist separator II and a one-way valve II in sequence in the reverse direction.

[0009] Preferably, a one-way valve III is connected in the forward conducting branch in the forward direction.

[0010] Preferably, the vacuum pump system includes a vacuum pump device and a vacuum tank which are conductively connected, and a manual stop valve II is connected between the vacuum pump device and the vacuum tank, and the vacuum tank is provided with m connection ports which correspond one to one with the negative pressure control channels.

[0011] Preferably, the negative pressure control channel includes a negative pressure sensor, a vacuum pressure gauge, a vacuum normally open solenoid valve II, a vacuum filter, a water droplet separator III, an oil mist separator III, an electric proportional valve II and a vacuum two-position three-way solenoid valve II connected in sequence in the reverse direction; the negative pressure sensor, the vacuum normally open solenoid valve II, the electric proportional valve II and the vacuum two-position three-way solenoid valve II are respectively communicated with the controller.

[0012] A pneumatic load loading control method adopts the above-mentioned pneumatic load loading control system, including a high-pressure gas source supply mode and a low-pressure gas source supply mode.

[0013] The high-pressure gas source supply mode comprises the following steps: S11, determining the number of positive pressure control channels required according to the number of test pieces in the test task, and connecting the test pieces to the corresponding positive pressure control channels one by one; S12, for each single test piece, after the gas source system generates gas source, the gas source flows through the manual stop valve Ⅰ and the two-position three-way solenoid valve Ⅰ in the positive pressure control channel in sequence, and then reaches the electric proportional valve Ⅰ; S13, the electric proportional valve I performs PID closed-loop control according to the controller input command, and controls the output of the air flow to meet the test pressure requirements; S14, the airflow after PID closed-loop control flows through the forward conduction branch in the positive pressure control channel, the safety valve, the normally open solenoid valve I and the pressure gauge in sequence, and finally reaches the pressure sensor and the test piece; S15, the air pressure sensor feeds back the measured air pressure value inside the test piece to the controller in real time for PID closed-loop control; S16, the controller determines whether the air pressure in the test piece exceeds the control command value; if not, the current air supply state is maintained and the process returns to step S15; if yes, the process proceeds to step S17; S17, the controller controls the gas in the test piece to flow through the pressure gauge, normally open solenoid valve I and the safety valve in sequence, and then returns to the electrical proportional valve I through the reverse conducting branch, and enters the atmosphere from the bypass of the electrical proportional valve I, so that the error between the pressure value in the test piece and the control command value is within the required range of test control accuracy.

[0014] The low-pressure gas source supply mode comprises the following steps: S21, determining the number of negative pressure control channels required according to the number of test pieces in the test task, and connecting the test pieces to the corresponding negative pressure control channels one by one; S22, for each single test piece, after the negative pressure control system generates a vacuum source, the air in the test piece flows through the vacuum pressure gauge, vacuum normally open solenoid valve II, vacuum filter, water droplet separator III and oil mist separator III in the negative pressure control channel in sequence, and then reaches the electric proportional valve II; S23, the negative pressure sensor feeds back the measured vacuum value inside the test piece to the controller in real time for PID closed-loop control; S24, the electric proportional valve II performs PID closed-loop control according to the controller input command to control the amount of air flowing through the electric proportional valve II. The air that has undergone PID closed-loop control eventually flows into the negative pressure control system through the vacuum two-position three-way solenoid valve II, so that the error between the vacuum degree in the test piece and the control command value is within the test control accuracy requirement range.

[0015] Beneficial technical effects brought by the present invention: 1) The technical solution discloses a pneumatic load loading control system, which can simultaneously meet the pressure charging test control requirements of multiple test pieces and the pressure extraction test control requirements of multiple test pieces by only setting the number of positive pressure control channels and negative pressure control channels according to the needs. Moreover, the entire control process only needs to integrate PID closed-loop control technology to achieve convenient, safe and reliable intelligent control through the controller.

[0016] 2) A pneumatic load loading control system method disclosed in the technical solution is based on a pneumatic load loading control system of the technical solution, which adopts electric proportional valve I / II (and air / negative pressure sensor) as the main servo control components, and forms a double closed-loop control system with the controller to achieve precise control of synchronously coordinating positive pressure filling and negative pressure extraction of multiple test pieces at the same time, improve the control accuracy of the test pneumatic load, and truly simulate the structural loading conditions of the test pieces under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The overall structural principle block diagram of the air pressure load control system; Figure 2 This is the principle block diagram of the composition structure of the gas source system; Figure 3 This is a block diagram of the structural principle of the positive pressure control channel; Figure 4 This is the block diagram of the composition structure of the vacuum pump system; Figure 5 This is a block diagram of the structural principles of the negative pressure control channel.

[0018] In the figure: 1. Controller; 2. Air source system; 3. Air distribution exhaust; 4. High-pressure filter; 5. High-pressure air exhaust; 6. High-pressure pressure reducing valve I; 7. High-pressure pressure reducing valve II; 8. Check valve I; 9. High-pressure air pressure gauge; 10. Low-pressure filter; 11. Low-pressure air exhaust; 12. Oil mist separator I; 13. Water droplet separator I; 14. Air filter I; 15. Dryer; 16. Low-pressure air pressure gauge; 17. Positive pressure control channel; 18. Manual stop valve I; 19. Two-position three-way solenoid valve I; 20. Electric proportional valve I; 21. Check valve III; 22. Safety valve; 23 , normally open solenoid valve Ⅰ; 24, pressure gauge; 25, pressure sensor; 26, air filter Ⅱ; 27, water droplet separator Ⅱ; 28, oil mist separator Ⅱ; 29, one-way valve Ⅱ; 30, vacuum pump system; 31, vacuum pump device; 32, vacuum tank; 33, manual stop valve Ⅱ; 34, negative pressure control channel; 35, negative pressure sensor; 36, vacuum pressure gauge; 37, vacuum normally open solenoid valve Ⅱ; 38, vacuum filter; 39, water droplet separator Ⅲ; 40, oil mist separator Ⅲ; 41, electric proportional valve Ⅱ; 42, vacuum two-position three-way solenoid valve Ⅱ. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0020] Therefore, the following detailed description of the invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example 1 This embodiment discloses a pneumatic load loading control system and method. As a preferred embodiment of the present invention, the control system includes a controller 1, a positive pressure control system and a negative pressure control system. Among them: the positive pressure control system includes an air source system 2 and n positive pressure control channels 17, where n≥1; all positive pressure control channels 17 are respectively connected to the air source system 2, and all positive pressure control channels 17 are respectively connected to the controller 1 for communication. The negative pressure control system includes a vacuum pump system 30 and m negative pressure control channels 34, where m≥1; all negative pressure control channels 34 are respectively connected to the vacuum pump system 30, and all negative pressure control channels 34 are respectively connected to the controller 1 for communication.

[0022] Based on the composition structure of the above control system, the air pressure load loading control method includes a high-pressure air source supply mode and a low-pressure air source supply mode.

[0023] The high-pressure gas source supply mode is applied to the pressurization test of the test piece (such as the aircraft's fuel tank, air inlet, cockpit, etc.). Each single positive pressure control channel 17 can meet the pressurization condition of a test piece, and all positive pressure control channels 17 are uniformly controlled by the controller 1.

[0024] The low-pressure air source supply mode is applied to the pressure extraction test of the test piece (such as the aircraft's fuel tank, air intake, cockpit, etc.). Each single negative pressure control channel 34 can meet the pressure extraction condition of a test piece, and all negative pressure control channels 34 are uniformly controlled by the controller 1.

[0025] In summary, the technical solution only needs to set the number of positive pressure control channels 17 and negative pressure control channels 34 according to the needs, so as to simultaneously meet the pressure charging test control requirements of multiple (n) test pieces and the pressure extraction test control requirements of multiple (m) test pieces, and the entire control process only needs to integrate PID closed-loop control technology to achieve convenient, safe and reliable intelligent control through the controller 1. Therefore, the controller 1 is not limited to a specific model, and only needs to meet the number of its control terminals ≥ n + m, such as Figure 1As shown, ZCH represents the control end of the positive pressure control channel 17, and FCH represents the control end of the negative pressure control channel 34.

[0026] Example 2 This embodiment discloses a pneumatic load loading control system and method. As a preferred embodiment of the present invention, the control system includes a controller 1, a positive pressure control system and a negative pressure control system. Among them: the positive pressure control system includes an air source system 2 and n positive pressure control channels 17, where n≥1; all positive pressure control channels 17 are respectively connected to the air source system 2, and all positive pressure control channels 17 are respectively connected to the controller 1 for communication. The negative pressure control system includes a vacuum pump system 30 and m negative pressure control channels 34, where m≥1; all negative pressure control channels 34 are respectively connected to the vacuum pump system 30, and all negative pressure control channels 34 are respectively connected to the controller 1 for communication.

[0027] Furthermore, the gas source system 2 is a high-pressure gas cylinder or a gas source device for unified gas supply in the factory, which produces a standard gas supply pressure and does not need to be managed by the controller 1. If the produced pressure is not appropriate, it can be adjusted by a multi-stage pressure reducing valve. Specifically, in the present technical solution, the gas source system 2 includes a high-pressure gas source channel, a low-pressure gas source channel and a gas distribution row 3, and the gas distribution row 3 is provided with an air inlet and n gas outlets corresponding to the positive pressure control channel 17. The high-pressure gas source channel includes a high-pressure filter 4, a high-pressure gas exhaust 5, a high-pressure pressure reducing valve Ⅰ6, a high-pressure pressure reducing valve Ⅱ7 and a one-way valve Ⅰ8 connected in sequence along the positive direction, and a high-pressure air pressure gauge 9 is connected to the high-pressure gas exhaust 5. The low-pressure gas source channel includes a low-pressure filter 10, a low-pressure gas exhaust 11, an oil mist separator Ⅰ12, a water droplet separator Ⅰ13, an air filter Ⅰ14 and a dryer 15 connected in sequence along the positive direction, and a low-pressure air pressure gauge 16 is connected to the low-pressure gas exhaust 11. The output end of the one-way valve I8 is connected to the low-pressure gas exhaust 11, and the output end of the dryer 15 is connected to the air inlet of the gas distribution exhaust 3.

[0028] Among them, the high-pressure gas source is usually supplied by a high-pressure gas cylinder (canned compressed air, etc.), the upper limit of the pressure can reach 15MPa, and the lowest is also several MPa. During use, it is necessary to use a high-pressure filter 4 to clean the gas source, and use a two-stage pressure reducing valve (high-pressure pressure reducing valve I6 and high-pressure pressure reducing valve II7) to reduce the gas source pressure to the working pressure range for test use; the function of the high-pressure gas pressure gauge 9 is to check the pressure values ​​before and after pressure reduction to ensure safety and that the pressure size meets the requirements.

[0029] In addition, the output end of the one-way valve Ⅰ8 processed in the present technical solution is connected to the low-pressure gas exhaust 11. When working, the high-pressure gas source and the low-pressure gas source must be selected from each other and cannot work at the same time. When the low-pressure gas source is supplying gas, the one-way valve Ⅰ8 prevents the low-pressure gas from flowing back into the high-pressure gas source channel to avoid leakage.

[0030] In the low-pressure gas source, the low-pressure gas exhaust 11 distributes the gas source to each charging channel in parallel; the low-pressure air gauge 16 is used to visually check whether the pressure value meets the working requirements; the oil mist separator, water droplet separator, air filter and dryer 15 are used to purify the gas source, including removing impurities, water, oil, and drying, to protect the electric proportional valve in this technical solution (specifically the electric proportional valve Ⅰ20 in the positive pressure control channel 17).

[0031] Example 3 The present embodiment discloses a pneumatic load loading control system and method, as a preferred implementation mode of the present invention, that is, based on embodiment 1 or 2, its positive pressure control channel 17 includes a manual stop valve Ⅰ18, a two-position three-way solenoid valve Ⅰ19, an electrical proportional valve Ⅰ20, a forward conducting branch, a safety valve 22, a normally open solenoid valve Ⅰ23, a pressure gauge 24 and an air pressure sensor 25 connected in sequence along the forward direction, and a reverse conducting branch is connected in parallel at both ends of the forward conducting branch; the two-position three-way solenoid valve Ⅰ19, the electrical proportional valve Ⅰ20, the normally open solenoid valve Ⅰ23 and the air pressure sensor 25 are respectively connected to the controller 1 for communication.

[0032] Among them, the manual stop valve Ⅰ18 is opened when working and closed when not working to ensure safety; the two-position three-way solenoid valve Ⅰ19 is used to assist the control of the electrical proportional valve Ⅰ20, which is opened during normal pressure control and closed when the pressure in the test piece is reduced or released (for emergency safety protection); the electrical proportional valve Ⅰ20 receives the instructions of the controller 1 to achieve precise control of the pressure in the test piece, and is the actuator of the PID control of the controller 1. Regarding PID control, the core is to compare the command with the feedback value of the pressure sensor, and then output the control instruction to the electrical proportional valve based on the error to adjust the command and feedback, and finally achieve consistency between the command and feedback. The existing typical PID control logic can be used.

[0033] Furthermore, the reverse conducting branch is connected in sequence with an air filter II 26, a water droplet separator II 27, an oil mist separator II 28 and a one-way valve II 29 in the reverse direction. The forward conducting branch is connected in the forward direction with a one-way valve III 21.

[0034] Therefore, during normal pressure control, the airflow flows to the test piece through the one-way valve III21 in the forward conducting branch. When the pressure inside the test piece is higher than the command, the airflow will flow in the reverse direction through the air filter II26, the water droplet separator II27, the oil mist separator II28 and the one-way valve II29 in the reverse conducting branch. That is, the main functions of the one-way valve II29 and the one-way valve III21 are to control the flow direction of the airflow, the pressure is charged from the forward conducting branch, and the pressure regulating reflux is from the reverse conducting branch. The role of the air filter II26 replacing the water droplet separator II27 is to clean the gas flowing out of the test piece, including removing impurities, oil, water, etc., and protecting the electrical proportional valve I20. The safety valve 22 and the normally open solenoid valve I23 are used to play a safety protection role during the test process. The barometer 24 is used to visually check the pressure value inside the test piece, which has the function of safety monitoring.

[0035] Furthermore, the controller 1 also provides an emergency protection function by controlling the two-position three-way solenoid valve Ⅰ19 and the normally open solenoid valve Ⅰ23 at the front and rear ends of the electrical proportional valve Ⅰ20. During emergency protection, the controller 1 cuts off the power supply of the two-position three-way solenoid valve Ⅰ19 and the normally open solenoid valve Ⅰ23, allowing the test piece to communicate with the atmosphere on the one hand, and cutting off the gas supply on the other hand.

[0036] Example 4 This embodiment discloses a pneumatic load loading control system and method, as a preferred embodiment of the present invention, that is, based on embodiment 1, 2 or 3, its vacuum pump system 30 includes a vacuum pump device 31 and a vacuum tank 32 that are conductively connected, and a manual stop valve II 33 is connected between the vacuum pump device 31 and the vacuum tank 32, and the vacuum tank 32 is provided with m connection ports corresponding to the negative pressure control channel 34. Among them, the combination of the vacuum pump device 31 and the vacuum tank 32 is a general mature product, providing a negative pressure environment (volume tank). The manual stop valve II 33 is opened during work and closed during non-working hours for safety.

[0037] Example 5 The present embodiment discloses a pneumatic load loading control system and method, as a preferred implementation mode of the present invention, that is, based on Embodiment 1, 2, 3 or 4, its negative pressure control channel 34 includes a negative pressure sensor 35, a vacuum pressure gauge 36, a vacuum normally open solenoid valve II37, a vacuum filter 38, a water droplet separator III39, an oil mist separator III40, an electric proportional valve II41 and a vacuum two-position three-way solenoid valve II42 connected in sequence in the reverse direction; the negative pressure sensor 35, the vacuum normally open solenoid valve II37, the electric proportional valve II41 and the vacuum two-position three-way solenoid valve II42 are respectively connected to the controller 1 for communication.

[0038] In actual use, the vacuum pressure gauge 36 is used to visually monitor the negative pressure in the test piece. The normally open vacuum solenoid valve Ⅱ37 opens when pressure relief or emergency protection occurs, connects to the atmosphere, and protects the safety of the test piece. The function of the vacuum filter 38, the water droplet separator Ⅲ39, and the oil mist separator Ⅲ40 is to clean the gas flowing out of the test piece, including removing impurities, oil, water, etc., and protecting the electric proportional valve Ⅱ41. The electric proportional valve Ⅱ41 is an actuator of PID control, which realizes precise control of negative pressure. Regarding PID control, the core is to compare the command with the feedback value of the pressure sensor, and then adjust the electric proportional valve based on the error output control instruction, and finally achieve consistency between the command and feedback. The existing typical PID control logic can be used.

[0039] Furthermore, the controller 1 also provides an emergency protection function by controlling the vacuum two-position three-way solenoid valve Ⅱ42 and the vacuum normally open solenoid valve Ⅱ37 at the front and rear ends of the electrical proportional valve Ⅱ41. During emergency protection, the controller 1 cuts off the power supply of the vacuum two-position three-way solenoid valve Ⅱ42 and the vacuum normally open solenoid valve Ⅱ37, allowing the test piece to communicate with the atmosphere on the one hand, and cutting off the connection path of the vacuum tank 32 on the other hand.

[0040] Example 6 This embodiment discloses a pneumatic load loading control method. As a preferred implementation mode of the present invention, a pneumatic load loading control system disclosed in Embodiment 1, 2, 3, 4 or 5 is adopted, including a high-pressure gas source supply mode and a low-pressure gas source supply mode.

[0041] The high pressure gas supply mode includes the following steps: S11, according to the number of test pieces in the test task, determine the number of positive pressure control channels 17 required, and connect the test pieces to the corresponding positive pressure control channels 17 one by one; S12, for each single test piece, after the gas source system 2 generates gas source, the gas source flows through the manual stop valve Ⅰ18 and the two-position three-way solenoid valve Ⅰ19 in the positive pressure control channel 17 in sequence, and reaches the electric proportional valve Ⅰ20; S13, the electric proportional valve Ⅰ20 performs PID closed-loop control according to the input command of the controller 1, and controls the output of the air flow to meet the pressure required by the test; S14, the airflow after PID closed-loop control flows through the forward conducting branch in the positive pressure control channel 17, the safety valve 22, the normally open solenoid valve I 23 and the pressure gauge 24 in sequence, and finally reaches the pressure sensor 25 and the test piece; S15, the air pressure sensor 25 feeds back the measured air pressure value inside the test piece to the controller 1 in real time for PID closed-loop control; S16, the controller 1 determines whether the air pressure in the test piece exceeds the control command value; if not, the current air supply state is maintained and the process returns to step S15; if yes, the process proceeds to step S17; S17, the controller 1 controls the gas in the test piece to flow through the pressure gauge 24, the normally open solenoid valve I 23 and the safety valve 22 in sequence, and then returns to the electrical proportional valve I 20 through the reverse conduction branch, and is introduced into the atmosphere from the bypass of the electrical proportional valve I 20, so that the error between the pressure value in the test piece and the control command value is within the test control accuracy requirement range; The low-pressure gas supply mode includes the following steps: S21, determining the number of negative pressure control channels 34 required according to the number of test pieces in the test task, and connecting the test pieces to the corresponding negative pressure control channels 34 one by one; S22, for each single test piece, after the negative pressure control system generates a vacuum source, the air in the test piece flows through the vacuum pressure gauge 36, the vacuum normally open solenoid valve II 37, the vacuum filter 38, the water droplet separator III 39 and the oil mist separator III 40 in the negative pressure control channel 34 in sequence, and reaches the electric proportional valve II 41; S23, the negative pressure sensor 35 feeds back the measured vacuum value inside the test piece to the controller 1 in real time for PID closed-loop control; S24, the electric proportional valve Ⅱ41 performs PID closed-loop control according to the input command of the controller 1 to control the amount of air flowing through the electric proportional valve Ⅱ41. The air after PID closed-loop control finally flows into the negative pressure control system through the vacuum two-position three-way solenoid valve Ⅱ42, so that the error between the vacuum degree in the test piece and the control command value is within the required range of test control accuracy.

[0042] The implementation of this embodiment is based on a pneumatic load loading control system disclosed in the technical solution. The pneumatic load loading control system adopts an electrical proportional valve (electrical proportional valve I 20 and electrical proportional valve II 41) and an air / negative pressure sensor 35 as a main servo controller 1, and forms a double closed-loop control system with the controller 1, so as to realize precise control of synchronously coordinating positive pressure filling and negative pressure extraction of multiple test pieces at the same time, improve the control accuracy of the test pneumatic load, and truly simulate the structural loading conditions of the test pieces under different working conditions.

Claims

1. A pneumatic load control system, characterized in that: It comprises a controller (1), a positive pressure control system and a negative pressure control system; The positive pressure control system comprises an air source system (2) and n positive pressure control channels (17), wherein n≥1; all positive pressure control channels (17) are respectively connected to the air source system (2), and all positive pressure control channels (17) are respectively connected to the controller (1); The negative pressure control system comprises a vacuum pump system (30) and m negative pressure control channels (34), wherein m≥1; all negative pressure control channels (34) are respectively conductively connected to the vacuum pump system (30), and all negative pressure control channels (34) are respectively communicatively connected to the controller (1).

2. A pneumatic load loading control system as claimed in claim 1, characterized in that: The gas source system (2) comprises a high-pressure gas source channel, a low-pressure gas source channel and a gas distribution row (3), wherein the gas distribution row (3) is provided with an air inlet and n air outlets corresponding one to one with the positive pressure control channels (17); The high-pressure gas source channel comprises a high-pressure filter (4), a high-pressure gas exhaust (5), a high-pressure pressure reducing valve I (6), a high-pressure pressure reducing valve II (7) and a one-way valve I (8) connected in sequence along the forward direction, and the high-pressure gas exhaust (5) is connected to a high-pressure gas pressure gauge (9); The low-pressure air source channel comprises a low-pressure filter (10), a low-pressure air exhaust (11), an oil mist separator I (12), a water droplet separator I (13), an air filter I (14) and a dryer (15) which are connected in sequence in a forward direction, and a low-pressure air pressure gauge (16) is connected to the low-pressure air exhaust (11); The output end of the one-way valve I (8) is connected to the low-pressure gas exhaust (11), and the output end of the dryer (15) is connected to the air inlet of the gas distribution exhaust (3).

3. A pneumatic load loading control system as claimed in claim 1, characterized in that: The positive pressure control channel (17) comprises a manual stop valve I (18), a two-position three-way solenoid valve I (19), an electric proportional valve I (20), a forward conducting branch, a safety valve (22), a normally open solenoid valve I (23), a pressure gauge (24) and a pressure sensor (25) connected in sequence in a forward direction, and a reverse conducting branch is connected in parallel at both ends of the forward conducting branch; the two-position three-way solenoid valve I (19), the electric proportional valve I (20), the normally open solenoid valve I (23) and the pressure sensor (25) are respectively connected to the controller (1) for communication.

4. A pneumatic load control system as claimed in claim 3, characterized in that: The reverse conducting branch is connected in sequence in the reverse direction with an air filter II (26), a water drop separator II (27), an oil mist separator II (28) and a one-way valve II (29).

5. A pneumatic load control system as claimed in claim 3, characterized in that: A one-way valve III (21) is connected in the forward conducting branch in the forward direction.

6. A pneumatic load loading control system as claimed in claim 1, characterized in that: The vacuum pump system (30) comprises a vacuum pump device (31) and a vacuum tank (32) which are conductively connected, a manual stop valve II (33) is connected between the vacuum pump device (31) and the vacuum tank (32), and the vacuum tank (32) is provided with m connection ports which correspond one to one with the negative pressure control channels (34).

7. A pneumatic load loading control system as claimed in claim 1, characterized in that: The negative pressure control channel (34) comprises a negative pressure sensor (35), a vacuum pressure gauge (36), a vacuum normally open solenoid valve II (37), a vacuum filter (38), a water drop separator III (39), an oil mist separator III (40), an electric proportional valve II (41) and a vacuum two-position three-way solenoid valve II (42) which are connected in sequence in the reverse direction; the negative pressure sensor (35), the vacuum normally open solenoid valve II (37), the electric proportional valve II (41) and the vacuum two-position three-way solenoid valve II (42) are respectively connected to the controller (1) for communication.

8. A method for controlling air pressure load, characterized in that: A pneumatic load control system as claimed in any one of claims 1 to 7 is adopted, including a high-pressure gas source supply mode and a low-pressure gas source supply mode; The high-pressure gas source supply mode comprises the following steps: S11, determining the number of positive pressure control channels (17) required according to the number of test pieces in the test task, and connecting the test pieces one by one to the corresponding positive pressure control channels (17); S12, for each single test piece, after the air source system (2) generates air source, the air source flows through the manual stop valve I (18) and the two-position three-way solenoid valve I (19) in the positive pressure control channel (17) in sequence, and reaches the electric proportional valve I (20); S13, the electric proportional valve I (20) performs PID closed-loop control according to the input command of the controller (1), and controls the output of the air flow to meet the pressure required by the test; S14, the airflow after PID closed-loop control flows through the forward conducting branch in the positive pressure control channel (17), the safety valve (22), the normally open solenoid valve I (23) and the pressure gauge (24) in sequence, and finally reaches the pressure sensor (25) and the test piece; S15, the air pressure sensor (25) feeds back the measured air pressure value inside the test piece to the controller (1) in real time for PID closed-loop control; S16, the controller (1) determines whether the air pressure in the test piece exceeds the control command value; if not, the current air supply state is maintained and the process returns to step S15; if so, the process proceeds to step S17; S17, the controller (1) controls the gas in the test piece to flow through the pressure gauge (24), the normally open solenoid valve I (23) and the safety valve (22) in sequence, and then returns to the electric proportional valve I (20) through the reverse conducting branch, and is introduced into the atmosphere from the bypass of the electric proportional valve I (20), so that the error between the pressure value in the test piece and the control command value is within the test control accuracy requirement range; The low-pressure gas source supply mode comprises the following steps: S21, determining the number of negative pressure control channels (34) required according to the number of test pieces in the test task, and connecting the test pieces one by one to the corresponding negative pressure control channels (34); S22, for each single test piece, after the negative pressure control system generates a vacuum source, the air in the test piece flows through the vacuum pressure gauge (36) in the negative pressure control channel (34), the vacuum normally open solenoid valve II (37), the vacuum filter (38), the water droplet separator III (39) and the oil mist separator III (40) in sequence, and then reaches the electric proportional valve II (41); S23, the negative pressure sensor (35) feeds back the measured vacuum value inside the test piece to the controller (1) in real time for PID closed-loop control; S24, the electric proportional valve II (41) performs PID closed-loop control according to the input command of the controller (1), and controls the amount of air flowing through the electric proportional valve II (41). The air that has passed the PID closed-loop control finally flows into the negative pressure control system through the vacuum two-position three-way solenoid valve II (42), so that the error between the vacuum degree in the test piece and the control command value is within the test control accuracy requirement range. 。

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