A hydraulic system and method for simulating failure modes of an aviation hydraulic plunger pump

Abstract

The present application provides a hydraulic system and method for simulating the fault mode injection of an aviation hydraulic plunger pump, which belongs to the field of aerospace. The oil inlet of the aviation hydraulic plunger pump is connected to a fault injector to realize the simulation of various fault modes. Through the cooperation of two-position three-way reversing valve and related speed control valve, overflow valve and three-position four-way proportional servo valve and other components, various load conditions and different working conditions on the aircraft can be simulated. In the simulated load branch, throttling load, overflow load and throttling-overflow load can be simulated by adjusting the third proportional speed control valve, the second proportional overflow valve and the fourth proportional speed control valve; in the reproduction branch of the wing actuation working condition on the aircraft, the three-position four-way proportional servo valve can be used to drive the actuator to overcome the damping-spring-guide rail load simulation unit to reproduce the real working state during wing actuation. It can also realize the fault reproduction and accurate identification of the aviation hydraulic plunger pump, and improve the reliability of the fault diagnosis algorithm of the aviation hydraulic plunger pump and the health status prediction ability.

Description

Technical Field

[0001] The present application relates to the field of aerospace technology, and in particular to a hydraulic system and method for simulating the failure mode injection of an aviation hydraulic plunger pump. Background Art

[0002] Aircraft hydraulic piston pumps are one of the core power components in aircraft hydraulic transmission systems, characterized by compact structure, high rated pressure, high power density, and large flow rate. Factors such as vibration, temperature rise, and pulsation directly limit the reliability and service life of aircraft hydraulic pumps. Furthermore, as hydraulic systems move toward higher pressures, the probability of fatal failures such as leakage, abnormal wear of friction pairs caused by temperature rise and pressure pulsation, spindle fracture, excessive return oil pressure, rotor cracks, and casing cracks in hydraulic piston pumps has increased significantly. Therefore, effective monitoring of the operating status of aircraft hydraulic piston pumps and accurate assessment of their health within limited space and weight constraints to maximize aircraft flight safety are current research priorities.

[0003] Currently, most methods for fault mode injection simulation of aircraft hydraulic piston pumps are based on simulation and mathematical models. However, since the operating performance of aircraft hydraulic piston pumps is affected by multiple factors such as material properties, machining accuracy, and harsh environments, they are prone to failure. Furthermore, aircraft hydraulic piston pumps have numerous parts, complex structures, and variable operating conditions. Consequently, the resulting failures are uncertain and hidden. Furthermore, a single failure mode can easily lead to other concurrent failure modes, resulting in concurrency and multiplicity. Therefore, the design of new hydraulic systems and test methods for fault mode injection simulation of aircraft hydraulic piston pumps is particularly important. Summary of the Invention

[0004] In view of this, the present application provides an aviation hydraulic plunger pump fault mode injection simulation hydraulic system and method, which can achieve aviation hydraulic plunger pump fault reproduction and accurate identification, and improve the reliability of the aviation hydraulic plunger pump fault diagnosis algorithm and the health status prediction ability.

[0005] Specifically, this application is implemented through the following technical solutions:

[0006] In a first aspect, the present application provides an aviation hydraulic plunger pump failure mode injection simulation hydraulic system, the hydraulic system comprising:

[0007] An aviation hydraulic plunger pump, wherein the oil inlet of the aviation hydraulic plunger pump is connected to the low-pressure oil port of the first proportional speed regulating valve and a fault injector, and is connected to the self-pressurizing oil tank via the high-pressure oil port of the first proportional speed regulating valve, and the fault injector is used to inject contaminants; the oil return port of the aviation hydraulic plunger pump is connected to the self-pressurizing oil tank via the low-pressure oil port of the first proportional relief valve;

[0008] A two-position three-way reversing valve, wherein the oil outlet of the aviation hydraulic plunger pump is connected to the inlet of the two-position three-way reversing valve, the first outlet of the two-position three-way reversing valve is connected to the simulated load branch, and the second outlet of the two-position three-way reversing valve is connected to the reproducing branch of the wing actuation working condition on the aircraft;

[0009] The simulated load branch is provided with a third proportional speed regulating valve, a second proportional relief valve and a fourth proportional speed regulating valve, the first outlet of the two-position three-way reversing valve is connected to the high-pressure oil port of the third proportional speed regulating valve, and the low-pressure oil port of the third proportional speed regulating valve is simultaneously connected to the high-pressure oil port of the fourth proportional speed regulating valve and the high-pressure oil port of the second proportional relief valve;

[0010] The reproduction branch is provided with a three-position four-way proportional servo valve and an actuator cylinder. The second outlet of the two-position three-way reversing valve is connected to the first inlet of the three-position four-way proportional servo valve, and is connected to the actuator cylinder through the first outlet of the three-position four-way proportional servo valve. The actuator cylinder is connected to the damping-spring-guide rail load simulation unit.

[0011] A second aspect of the present application provides a method for injecting a simulated hydraulic pressure into a failure mode of an aviation hydraulic plunger pump, the simulated hydraulic pressure method comprising:

[0012] Obtaining the current test state type, where the test state type includes a normal working state test and a fault working state test;

[0013] Determine the failure mechanism of the test state type and obtain the system components affected by the current state test;

[0014] Determining a simulation scheme based on the affected system components, the simulation scheme including a normal state adjustment mode and a fault state adjustment mode;

[0015] According to the simulation scheme, normal working state data and fault working state data are obtained, and the two types of data are compared to extract time-frequency domain fault characteristic parameters.

[0016] This application provides a hydraulic system and method for simulating fault mode injection in an aviation hydraulic plunger pump. First, by connecting the oil inlet of the aircraft hydraulic plunger pump to a fault injector, the fault injector can, under the control of the aircraft hydraulic plunger pump's oil inlet, inject external contaminants to simulate a fault condition exceeding the contaminant limit. Simultaneously, the aircraft hydraulic plunger pump simulates structural failure by quantifying returned faulty parts or artificially injecting abnormal wear of varying damage levels. Secondly, a combination of a speed control valve and a relief valve is used to simulate various load types. A damping-spring-guide rail load simulation unit is used to directly replicate the actual operating conditions during wing actuation. A two-position, three-way reversing valve can also be used to switch between the simulated load branch and the branch that replicates the onboard wing actuation conditions. In the simulated load branch, throttling load, overflow load and throttling-overflow load can be simulated by adjusting the third proportional speed control valve, the second proportional relief valve and the fourth proportional speed control valve; in the reproduction branch of the wing actuation working condition on the aircraft, the three-position four-way proportional servo valve can be used to drive the actuator to overcome the damping-spring-guide load simulation unit to reproduce the real working state of the wing actuation, thereby realizing the simulation of various loads. There is no need to establish a complex simulation model, and conventional components can be used to realize the simulation of various working conditions. Finally, the aviation hydraulic plunger pump fault mode injection simulation hydraulic system proposed in this application is based on the connection relationship of actual components. Compared with the simulation model and numerical simulation method, it not only improves the data reliability of the typical fault mode injection test of the hydraulic plunger pump, but also makes the fault simulation more consistent with the actual airborne environment. At the same time, it can complete the reproduction of various real fault modes such as abnormal wear of the friction pair, main shaft fracture, excessive contamination, excessive return oil pressure, rotor cracks and shell cracks, fault injection and fault test data collection and analysis, as well as verification test of the fault diagnosis algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a structural diagram of Example 1 of the aviation hydraulic plunger pump failure mode injection simulation hydraulic system provided by this application;

[0018] Figure 2 This is a flow chart of Example 1 of the method for injecting simulated hydraulic pressure into a failure mode of an aviation hydraulic plunger pump provided by this application;

[0019] Figure 3 This is a diagram showing the fault generation principles and solutions corresponding to the fault types shown in this application;

[0020] Figure 4 This is a schematic diagram of the working principle of the aviation hydraulic plunger pump shown in this application;

[0021] Description of reference numerals:

[0022] 1-First servo motor, 2-Aviation hydraulic plunger pump, 3-Fault injector, 4-First proportional speed control valve, 5-First filter, 6-First flow meter, 7-First proportional relief valve, 8-Safety valve, 9-Unloading valve, 10-Quantitative gear pump, 11-Second filter, 12-Radiator, 13-Second servo motor, 14-Check valve, 15-Third filter, 16-Second flow meter, 17-Accumulator, 18-Solenoid switch valve, 19-Second proportional speed control valve, 20-Two-position three-way reversing valve, 21-First pressure and temperature sensor, 22-Third proportional speed control valve, 23-Fourth proportional speed control valve, 24-Second proportional relief valve, 25-First Three-proportional relief valve, 26-second pressure and temperature sensor, 27-fourth filter, 28-fifth proportional speed control valve, 29-three-position four-way proportional servo valve, 30-hydraulic lock, 31-third pressure and temperature sensor, 32-fourth pressure and temperature sensor, 33-actuator, 34-displacement sensor, 35-mass block, 36-damper, 37-spring, 38-sliding guide rail, 39-fifth pressure and temperature sensor, 40-fifth filter, 41-self-pressurized oil tank, 42-sixth pressure and temperature sensor, 43-seventh pressure and temperature sensor, 44-eighth pressure and temperature sensor, 45-contamination sensor, 46-ninth pressure and temperature sensor. DETAILED DESCRIPTION

[0023] Exemplary embodiments are described in detail herein, with examples illustrated in the accompanying drawings. When the following description refers to the drawings, identical numerals in different drawings represent identical or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with this application.

[0024] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms "a," "the," and "the" used in this application are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0025] It should be understood that although the terms first, second, third, etc. may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0026] Specific embodiments are given below to introduce the technical solutions of the present application in detail.

[0027] Figure 1 This is a structural diagram of the first embodiment of the hydraulic system for injecting simulated hydraulic pressure into the failure mode of the aviation hydraulic plunger pump provided by this application. Figure 1 The system provided in this embodiment may include:

[0028] An aviation hydraulic plunger pump 2, wherein the oil inlet P2 of the aviation hydraulic plunger pump 2 is connected to the low-pressure oil port T4 of the first proportional speed regulating valve 4 and the fault injector 3, and is connected to the self-pressurizing oil tank 41 via the high-pressure oil port P4 of the first proportional speed regulating valve 4. The fault injector 3 is used to inject contaminants; the oil return port of the aviation hydraulic plunger pump 2 is connected to the self-pressurizing oil tank via the low-pressure oil port T7 of the first proportional relief valve 7;

[0029] A two-position three-way reversing valve 20, wherein the oil outlet T2 of the aviation hydraulic plunger pump 2 is connected to the inlet A20 of the two-position three-way reversing valve 20, the first outlet B20 of the two-position three-way reversing valve 20 is connected to the simulated load branch, and the second outlet C20 of the two-position three-way reversing valve 20 is connected to the reproducing branch of the aircraft wing actuation working condition;

[0030] The simulated load branch is provided with a third proportional speed regulating valve 22, a second proportional relief valve 24 and a fourth proportional speed regulating valve 23. The first outlet B20 of the two-position three-way reversing valve 20 is connected to the high-pressure oil port P20 of the third proportional speed regulating valve 22. The low-pressure oil port T20 of the third proportional speed regulating valve 22 is simultaneously connected to the high-pressure oil port P23 of the fourth proportional speed regulating valve 23 and the high-pressure oil port P24 of the second proportional relief valve 24.

[0031] A three-position four-way proportional servo valve 29 and an actuator 33 are provided on the reproduction branch. The second outlet C20 of the two-position three-way directional control valve 20 is connected to the first inlet A29 of the three-position four-way proportional servo valve 29, and is connected to the actuator 33 through the first outlet B29 of the three-position four-way proportional servo valve 29. The actuator 33 is connected to the damping-spring-guide rail load simulation unit.

[0032] It should be noted that the aircraft hydraulic piston pump 2 is the core power element in the aircraft hydraulic transmission system, responsible for converting mechanical energy into hydraulic energy and providing pressurized oil to the entire hydraulic system. The fault injector 3 is used to vary the oil contamination and air content to simulate failures caused by abnormal wear and other factors. It can also inject contaminants such as well-mixed metal debris to simulate a failure mode in which excessive contaminants in the oil suction line exceed the specified limit.

[0033] This system utilizes a design that connects the oil inlet and return ports of an aviation hydraulic piston pump, utilizing a fault injector and adjustable control valves (speed control valve, relief valve) to simulate different fault modes. Specifically, the speed control valve is used to adjust the flow and speed of the hydraulic oil, enabling simulation of the hydraulic system's operating conditions under different operating conditions. The relief valve is used to control the pressure in the return oil path, allowing the system to simulate different fault modes under varying return oil pressures. Furthermore, the high-pressure oil port of the first proportional speed control valve is connected to the self-pressurizing tank, meaning that after the hydraulic oil pressure is regulated by the speed control valve, it can flow directly back to the self-pressurizing tank. By adjusting the valve opening of the first proportional speed control valve, the system can control the oil inlet pressure, thereby simulating operation of the hydraulic pump under different inlet pressure conditions. It should also be noted that the return port of the aviation hydraulic piston pump is connected to the self-pressurizing tank via the first proportional relief valve. This allows the excess hydraulic oil to flow back to the tank after the aircraft hydraulic piston pump completes its operation, adjusting the pressure via the relief valve. This allows simulation of different fault modes under varying return oil pressures. For example, when the oil return port is blocked, the aviation hydraulic plunger pump 2 generates tiny metal debris during operation, which can cause the oil return port to be blocked, resulting in poor oil return. Figure 1 Due to poor oil return, the pressure in the pump will gradually increase, and the corresponding temperature will also increase. The eighth pressure and temperature sensor 44 detects the pressure and temperature increase. When the oil flows to the connected first filter 5, the pressure difference between the high-pressure oil port and the low-pressure oil port of the first filter 5 will increase, and the presence of debris will increase the filtration load of the first filter. After a failure, the first flowmeter will detect that the flow rate has decreased. The first proportional relief valve 7 is used to regulate the system pressure. When the return oil port is blocked, the system pressure increases, and the first proportional relief valve 7 may attempt to open to release excess pressure. However, due to poor oil return, the regulating function of the relief valve may be limited, and it may not be able to effectively reduce the pressure to a normal level. In this system, the return oil pressure under different blockage conditions can be simulated by adjusting the relief pressure of the first proportional relief valve 7. At the same time, the pressure and flow of the return oil port can be monitored in real time by combining the first flowmeter 6 and the eighth pressure and temperature sensor 44.

[0034] When implementing it, refer to Figure 1 The component connection method of the oil return port path of the aviation hydraulic plunger pump includes: the oil return port of the aviation hydraulic plunger pump 2 passes through the high-pressure oil port P5 and the low-pressure oil port T5 of the first filter 5, flows through the high-pressure oil port P6 and the low-pressure oil port T6 of the first flowmeter 6, and is connected to the high-pressure oil port P7 of the first proportional relief valve 7, the low-pressure oil port T7 of the first proportional relief valve 7 is connected to the self-pressurizing oil tank 41, and the eighth pressure and temperature sensor 44 is connected to the high-pressure oil port P5 of the first filter 5.

[0035] In addition, the oil outlet path of the aviation hydraulic plunger pump also includes: the contamination sensor 45 is connected to the oil inlet P9 of the unloading valve 9 and the oil inlet P8 of the safety valve 8; the oil outlet T9 of the unloading valve 9 and the oil outlet T8 of the safety valve 8 are connected to the self-pressurized oil tank 41.

[0036] It should be noted that during hydraulic system operation, due to component wear and aging of the hydraulic oil, the return oil may carry some particulate impurities. If these impurities are not filtered out and re-enter the hydraulic system, they may cause wear to the plunger pump and other precision components, reducing the reliability and life of the system. The eighth pressure and temperature sensor 44 is connected to the high-pressure oil port P5 of the first filter 5 and can monitor the pressure and temperature of the return oil before it passes through the filter in real time. If the pressure is too high, it may indicate a clogged filter or other problems in the return oil line. If the temperature is abnormal, it may indicate overheating or other faults in the system. By monitoring the pressure and temperature of the return oil, potential problems can be discovered in a timely manner.

[0037] Furthermore, contamination sensor 45 is connected to the oil inlet P9 of unloading valve 9 and the oil inlet P8 of safety valve 8. Unloading valve 9 and safety valve 8 serve as safety protection in the hydraulic system. When system pressure is too high, safety valve 8 automatically opens, releasing excess pressurized oil back to the self-boosting tank 41, preventing component damage or other hazards caused by excessive system pressure. Unloading valve 9 automatically opens and releases hydraulic oil back to the self-boosting tank 41 when system pressure reaches a certain value, reducing system pressure.

[0038] Please continue to refer to Figure 1 The first servo motor 1 is connected to the aviation hydraulic plunger pump 2, the oil outlet T2 of the aviation hydraulic plunger pump 2 is connected to the seventh pressure and temperature sensor 43, and after flowing through the contamination sensor 45, it is connected to the oil inlet P14 of the one-way valve 14;

[0039] The oil outlet T14 of the one-way valve 14 is connected to the high-pressure oil port P15 of the third filter 15; the low-pressure oil port T15 of the third filter 15 is connected to the high-pressure oil port P16 of the second flowmeter 16; the low-pressure oil port T16 of the second flowmeter 16 is also connected to the inlet and outlet oil ports P17 of the accumulator 17, the solenoid switch valve 18 and the high-pressure oil port P19 of the second proportional speed control valve 19, and the low-pressure oil port T19 of the second proportional speed control valve 19 is connected to the inlet A20 of the two-position three-way reversing valve 20.

[0040] The first servo motor 1 provides rotational power to the aircraft hydraulic piston pump 2, driving its operation. The pressure and temperature sensor 43 monitors the pressure and temperature at the oil outlet T2 of the aircraft hydraulic piston pump 2 in real time. During fault simulation, this sensor provides important status data for fault monitoring and diagnosis of the entire hydraulic system. It should be noted that during fault simulation, changes in pressure, temperature, flow, and other data can be used to determine the cause (hence the inclusion of multiple pressure and temperature sensors and flow meters in the system).

[0041] It should also be noted that the contamination sensor 45 is used to monitor the contamination level of the hydraulic oil flowing through the hydraulic system. If there are particles, impurities or other contaminants in the hydraulic oil, the sensor will detect it and provide feedback. After the hydraulic oil flows through the contamination sensor 45, it enters the oil inlet P14 of the one-way valve 14. The function of the one-way valve 14 is to ensure that the hydraulic oil can only flow in one direction, prevent backflow in the hydraulic system, and ensure the directionality of the oil flow. The hydraulic oil output by the one-way valve 14 enters the third filter 15 to further remove impurities or contaminants in the hydraulic oil and ensure that the hydraulic oil flowing into the downstream components is clean. In addition, by providing an accumulator 17, it plays the role of storing energy, which can balance the pressure fluctuations of the system and quickly release the hydraulic oil when needed to compensate for the energy needs of the system. By providing an electromagnetic switch valve 18, it can be used to control the on and off of the hydraulic oil.

[0042] The complete simulated load branch is introduced below:

[0043] The first outlet B20 of the two-position three-way reversing valve 20 is connected to the first pressure and temperature sensor 21, and is connected to the high-pressure oil port P20 of the third proportional speed regulating valve 22 through the first pressure and temperature sensor 21. The low-pressure oil port T20 of the third proportional speed regulating valve 22 is also connected to the high-pressure oil port P23 of the fourth proportional speed regulating valve 23 and the high-pressure oil port P24 of the second proportional relief valve 24; wherein, the third proportional speed regulating valve 22 and the second proportional relief valve 24 are connected in series, and the third proportional speed regulating valve 22 and the The fourth proportional speed regulating valve 23 is connected in series, and the second proportional relief valve 24 and the fourth proportional speed regulating valve 23 are connected in parallel; the low-pressure oil port T23 of the fourth proportional speed regulating valve 23 and the low-pressure oil port T24 of the second proportional relief valve 24 are simultaneously connected to the high-pressure oil port P25 of the third proportional relief valve 25, the second pressure and temperature sensor 26, and the high-pressure oil port P27 of the fourth filter 27, and the low-pressure oil port T25 of the third proportional relief valve 25 and the low-pressure oil port T27 of the fourth filter 27 are connected to the self-pressurized oil tank 41.

[0044] It should be noted that the third proportional speed control valve 22, the fourth proportional speed control valve 23, and the second proportional relief valve 24, through a combination of series and parallel connections, can provide flexible adjustment methods. Specifically, the combination of series and parallel connections allows the system to control and limit flow and pressure in different ways under different conditions. For example, the series connection of the third proportional speed control valve 22 and the second proportional relief valve 24 can simulate throttling loads, adjusting pressure and flow to simulate hydraulic system behavior under different load conditions. The series connection of the third proportional speed control valve 22 and the fourth proportional speed control valve 23 can further refine the control of hydraulic flow speed and pressure, providing more accurate load simulation, especially when a wide range of flow changes is required. The parallel connection of the second proportional relief valve 24 and the fourth proportional speed control valve 23 allows the system to selectively direct hydraulic flow, simulate different types of relief and load conditions, and achieve flexible load switching. The simultaneous operation of the third proportional speed control valve 22, the fourth proportional speed control valve 23, and the second proportional relief valve 24 can achieve fine load adjustment and simulate more complex load conditions. For example, the ratio of throttling and relief can be adjusted as needed to simulate different types of hydraulic system loads, such as throttling, relief, or throttling-relief. By adjusting the opening of the three valves, the flow and pressure of the hydraulic oil can be changed, thereby adjusting the size and characteristics of the load.

[0045] In addition to the second proportional relief valve 24, a third proportional relief valve 25 is also provided to provide multiple safety features. When system pressure is too high, the relief valve automatically releases pressure, directing excess pressure back to the self-pressurizing tank 41. This prevents damage to equipment or malfunctions caused by excessive pressure. This multi-stage relief design also simulates different types of failures. For example, in an overload situation, the varying responses of the relief valves will directly affect the flow and pressure distribution of the hydraulic system.

[0046] The following is an introduction to the recurrence branch of the wing actuation working condition on the aircraft:

[0047] The second outlet C20 of the two-position three-way reversing valve 20 is connected to the high-pressure oil port P28 of the fifth proportional speed control valve 28, and the low-pressure oil port T28 of the fifth proportional speed control valve 28 is also connected to the ninth pressure and temperature sensor 46 and the first inlet A29 of the three-position four-way proportional servo valve 29; the first outlet B29 of the three-position four-way proportional servo valve 29 is connected to the first inlet A30 of the hydraulic lock 30, and the first outlet B30 of the hydraulic lock 30 is also connected to the third pressure and temperature sensor 31 and the rodless chamber A33 of the actuator 33; the rod chamber B33 of the actuator 33 is also connected to the fourth pressure and temperature sensor 32 and the second inlet C30 of the hydraulic lock 30, and the second outlet D30 of the hydraulic lock 30 is connected to the second inlet C29 of the three-position four-way proportional servo valve 29; the second outlet D29 of the three-position four-way proportional servo valve 29 is also connected to the fifth pressure and temperature sensor 39 and the high-pressure oil port P40 of the fifth filter 40, and the low-pressure oil port T40 of the fifth filter 40 is connected to the self-pressurizing oil tank 41.

[0048] It should be noted that the hydraulic lock 30 locks the position of the actuator 33, preventing it from moving when it is not required. The three-position, four-way proportional servo valve 29 can change the oil port connection through electromagnetic control, achieving precise control of the direction and speed of the actuator 33's movement. This precise control and flexible adjustment capability more realistically replicates the various operating conditions of an aviation hydraulic plunger pump. Furthermore, the actuator's exterior is connected to a damping-spring-guide rail load simulation unit, which comprises a mass 35, a damper 36, a spring 37, and a sliding guide 38. These interact to create resistance to the movement of the actuator 33, simulating the load conditions experienced in actual operating conditions. A displacement sensor 34 is also located above the actuator 33 to measure its displacement in real time, providing the system with accurate data on its motion.

[0049] In addition, in order to better ensure the efficient circulation of hydraulic oil, and to better monitor the pressure and temperature in real time, and maintain the safe and efficient operation of the hydraulic system, a quantitative gear pump 10 and a radiator 12 are provided on the self-pressurizing oil tank 41 to simulate the heat sink system of the hydraulic system. Specifically, the connection method of the heat sink part is:

[0050] The second servo motor 13 is connected to the quantitative gear pump 10. The oil inlet P11 of the quantitative gear pump 10 draws hydraulic oil from the self-boosting oil tank 41 through the oil inlet P11 and the oil return port T11 of the second filter 11;

[0051] The oil outlet T10 of the quantitative gear pump 10 flows through the oil inlet P12 and the oil return port T12 of the radiator 12 and flows back to the self-boosting oil tank 41;

[0052] The sixth pressure and temperature sensor 42 is connected to the self-pressurizing oil tank 41 .

[0053] It should be noted that the second servo motor 13 drives the quantitative gear pump 10 to draw hydraulic oil from the self-boosting oil tank 41 to provide a stable supply of hydraulic oil for the hydraulic system. The second filter 11 at the oil inlet P10 of the quantitative gear pump 10 can filter out impurities and protect system components; the oil outlet T10 of the quantitative gear pump 10 flows through the radiator 12 and then flows back to the self-boosting oil tank 41. The radiator 12 can dissipate the heat generated by the hydraulic oil during the circulation process, maintain the performance of the hydraulic oil, and provide a stable working environment for the fault mode injection simulation of the aviation hydraulic plunger pump.

[0054] It should be noted that the heat sink's configuration can measure hydraulic oil supply, filtration, and heat dissipation. The hydraulic oil supply condition refers to the process in which the second servo motor drives the fixed-displacement gear pump to draw hydraulic oil from the self-pressurized oil tank. During this process, the hydraulic system's supply stability can be assessed based on the pressure and flow data from the fixed-displacement gear pump (obtained via a pressure sensor and flowmeter). Large fluctuations in pressure and flow can affect the proper operation of the aircraft hydraulic piston pump and other components. To address this condition, the hydraulic oil supply can be optimized and system performance improved by adjusting the speed of the second servo motor or replacing the fixed-displacement gear pump with a different specification. The filtration condition monitors the performance of the second filter during the hydraulic oil filtration process. The pressure differential and impurity content data before and after the filter can be used to assess the filter's operating status and filtration effectiveness. If the pressure differential is excessive or the impurity content exceeds a certain standard, the filter can be cleaned or replaced promptly to protect system components from impurity damage. The heat dissipation condition monitors the radiator's performance during the heat dissipation process of the hydraulic oil. Temperature data at the radiator inlet and outlet and heat dissipation data can be used to assess the radiator's heat dissipation effectiveness. If the temperature is too high or the heat dissipation is insufficient, you need to check the working condition of the radiator, such as whether there is any blockage, whether the fan is operating normally, etc., or consider replacing a radiator with a larger heat dissipation capacity to ensure that the hydraulic system operates at an appropriate temperature.

[0055] The present application provides a hydraulic system for simulating fault mode injection in an aviation hydraulic plunger pump. First, by connecting the oil inlet of the aircraft hydraulic plunger pump to a fault injector, the fault injector can, under the control of the aircraft hydraulic plunger pump's oil inlet, inject external contaminants to simulate a fault condition exceeding the contaminant standard. Simultaneously, the aircraft hydraulic plunger pump simulates structural failure by quantifying returned faulty parts or artificially injecting abnormal wear of varying damage levels. Second, a combination of a speed control valve and a relief valve is used to simulate various load types. A damping-spring-guide rail load simulation unit is used to directly replicate the actual operating conditions during wing actuation. A two-position, three-way reversing valve can also be used to switch between the simulated load branch and the branch that replicates the onboard wing actuation conditions. In the simulated load branch, throttling load, overflow load and throttling-overflow load can be simulated by adjusting the third proportional speed control valve, the second proportional relief valve and the fourth proportional speed control valve; in the reproduction branch of the wing actuation working condition on the aircraft, the three-position four-way proportional servo valve can be used to drive the actuator to overcome the damping-spring-guide rail load simulation unit, and reproduce the real working state of the wing during actuation, thereby realizing the simulation of various loads. There is no need to establish a complex simulation model, and conventional components can be used to realize the simulation of various working conditions. Finally, the aviation hydraulic plunger pump fault mode injection simulation hydraulic system proposed in this application is based on the connection relationship of actual components. Compared with the simulation model and numerical simulation method, it not only improves the data reliability of the typical fault mode injection test of the hydraulic plunger pump, making the fault simulation more in line with the actual airborne environment, but also can complete the reproduction of multiple real fault modes, fault injection and fault test data collection and analysis, as well as the verification test of the fault diagnosis algorithm. It should also be noted that the system is equipped with multiple pressure and temperature sensors, flow meters and displacement sensors, which can monitor key parameters such as pressure, temperature, flow and displacement of the actuator in the hydraulic system in real time, helping to detect abnormal conditions in the system in a timely manner and take corresponding measures.

[0056] Figure 2 This is a flow chart of the first embodiment of the method for injecting simulated hydraulic pressure into the failure mode of the aviation hydraulic plunger pump provided by this application. Figure 2 Based on the above system embodiment, the simulated hydraulic method includes:

[0057] S201. Obtain a current test state type, where the test state type includes a normal working state test and a fault working state test.

[0058] It should be noted that system parameters can be monitored in real time using sensors (such as pressure sensors, temperature sensors, and pollution sensors). For example, if parameters such as pressure, temperature, and flow are within a predetermined range and the pollution sensor indicates that the pollutant content is below a set threshold, the system is considered to be operating normally. If the monitored parameters are outside the normal range, such as if the pressure is too high or too low, the temperature is abnormal, and the pollution sensor indicates that the pollutant content exceeds the set threshold, the system is considered to be in a faulty operating state.

[0059] S202: Determine the failure mechanism of the test state type and obtain system components affected by the current state test.

[0060] It should be noted that determining the failure mechanism of the test state type and obtaining the system components affected by the current state test includes:

[0061] (1) Obtain the fault tree model corresponding to the test state type.

[0062] Fault tree analysis is a systematic method used to identify the causes and effects of system failures. In this embodiment, a fault tree model can be established based on failure mode impact and criticality analysis and expert experience knowledge, which should include fault tree models related to normal working state tests and faulty working state tests.

[0063] (2) Determine the connection status of each system component and the flow status of the hydraulic oil based on the fault tree model.

[0064] It should be noted that the fault tree model describes how potential fault events in a system can lead to system failure through different paths. By analyzing the different branches of the fault tree, the function and status of each system component under different fault modes can be determined. Specifically, based on the fault tree model, it is possible to determine whether the connection status of each component is normal or affected. When the connection status is normal, it indicates that the connection between the component and other components is complete and fault-free, and the hydraulic oil can flow normally. When the connection status is impaired, it indicates that a fault event (such as a leak, blockage, or valve failure) has caused the connection between components to be interrupted or the function to be impaired.

[0065] It's also important to note that hydraulic systems rely on the flow of oil to transfer energy. If a component fails, the flow of hydraulic oil will also be affected. Fault tree model analysis can be used to determine the flow of hydraulic oil in the system. If the flow path of hydraulic oil is obstructed or the pressure is abnormal, it indicates a component failure (the location of the obstruction or abnormality can be determined based on the location of the component failure).

[0066] (3) Determine the system components affected by the current state test based on the connection state and the hydraulic oil flow state.

[0067] By checking the connection status of each component in the system, it is possible to determine whether there are any physical connection problems and then determine which components may be affected. In the hydraulic system, the flow of hydraulic oil directly affects the operation of the system components. By combining the connection status of each component in the system and the flow status of hydraulic oil, it is possible to determine which components may be affected under the current fault or test state.

[0068] S203 : Determine a simulation scheme based on the affected system components, where the simulation scheme includes a normal state adjustment mode and a fault state adjustment mode.

[0069] It should be noted that the simulation scheme is determined based on the affected system components, including:

[0070] (1) Identify the normal state and the corresponding fault mode of the affected system components, and determine the type of fault occurring in the components based on the fault mode; the fault types include structural failure, cavitation failure, oil return blockage, and excessive pollutants.

[0071] It's important to note that by analyzing the impact of various components in the hydraulic system, we can identify which components are affected by the current fault condition and further analyze their corresponding normal operating conditions and possible failure modes. Furthermore, based on the failure mode, we can determine the type of component failure. Common failure types include structural failure, cavitation failure, oil return blockage, and excessive contaminants. Figure 3 Please refer to the diagram for the fault generation principle and solution corresponding to the fault type shown in this application. Figure 3 Structural failure may be caused by rotor cracks, oil separator cracks, plunger seat cracks, cylinder cracks, plunger wear, slipper wear and oil separator wear. Cavitation failure may be caused by the oil inlet pipeline being too thin and too long, insufficient self-boosting supply pressure, too small self-boosting supply flow or excessive inertia of the self-boosting system. Return oil blockage may be caused by return oil port blockage, excessive return oil port pressure resistance and too long return oil port pipeline. Excessive pollutants may be caused by pipe joint processing debris, plunger pump fatigue peeling debris, hydraulic pipeline shedding and external pollutants.

[0072] (2) Adjust system components based on the identified normal states and failure modes.

[0073] Please continue to refer to Figure 3 , adjust system components based on identified normal states and failure modes, including:

[0074] (i) Under normal conditions, adjust the corresponding overflow valve and speed control valve.

[0075] By adjusting the opening of each relief valve and speed control valve, the load type and hydraulic oil flow in the system can be adjusted to meet the actual working conditions.

[0076] (ii) When the fault type is structural failure, the aircraft hydraulic piston pump under test is disassembled, and normal components in the aircraft hydraulic piston pump are replaced with faulty components to perform a fault injection test to obtain performance and vibration characteristic test data under the fault state.

[0077] Figure 4 This is a schematic diagram of the working principle of the aviation hydraulic plunger pump shown in this application, please refer to Figure 4 When the fault type is structural failure, the aviation hydraulic plunger pump being tested can be disassembled. For example, taking the abnormal wear of the plunger seat as an example, returned faulty parts with different damage conditions can be selected for quantification, or abnormal wear failure modes with different damage levels can be artificially injected, and normal parts in the aviation hydraulic plunger pump can be replaced with faulty parts for fault injection testing to obtain performance and vibration characteristic test data under the fault state.

[0078] (iii) When the fault type is a cavitation fault, adjusting the valve core opening of the first proportional speed control valve to simulate a cavitation fault at the oil inlet of the aviation hydraulic plunger pump.

[0079] Referring to the above system, by adjusting the valve core opening of the first proportional speed control valve 4, it is possible to simulate the oil inlet cavitation fault caused by excessive oil inlet pressure resistance due to an overly long oil inlet pipeline or insufficient supply pressure.

[0080] (iiii) When the fault type is return oil blockage, the overflow pressure of the first proportional relief valve is adjusted to simulate the return oil pressure under different blockage conditions, and the pressure and flow of the return oil port of the aviation hydraulic plunger pump are monitored in real time through the first flow meter and the eighth pressure and temperature sensor.

[0081] It should be noted that the oil return flow rate of an aviation hydraulic plunger pump is a key indicator of its heat dissipation capacity. Tiny metal debris generated during the operation of the plunger pump often clogs the oil return port, resulting in poor oil return. Therefore, referring to the aforementioned system, the return oil pressure under different blockage conditions can be simulated by adjusting the relief pressure of the first proportional relief valve 7. Simultaneously, the first flowmeter 6 and the eighth pressure and temperature sensor 44 monitor the pressure and flow rate of the oil return port in real time.

[0082] (iiiii) When the fault type is excessive pollutants, pollutants are injected into the oil circuit through a fault injector to directly simulate the fault mode of excessive pollutants in the oil suction line of the aviation hydraulic plunger pump, and filters are connected to the oil outlet and return port of the aviation hydraulic plunger pump.

[0083] It should be noted that, referring to the previous system, the fault injector 3 can be used to inject evenly stirred metal debris and other pollutants into the oil circuit, which can directly simulate the fault mode of excessive pollutants in the hydraulic plunger pump suction line. Filters are connected to the oil outlet and return port of the aviation hydraulic plunger pump to prevent excessive pollutants from affecting other precision servo valves in the hydraulic system.

[0084] (3) Form a simulation plan based on the adjusted system state.

[0085] It should be noted that the simulation plan at least includes:

[0086] When the two-position three-way valve is reversed, the reversing path is determined according to the working conditions; when the reversing path is in the left position, by adjusting the opening of any two components among the third proportional speed regulating valve, the fourth proportional speed regulating valve and the second proportional relief valve, a throttling load or a relief load is simulated, and by adjusting the opening of the three components at the same time, a throttling-relief load is simulated;

[0087] When the reversing path is in the right position, the three-position four-way proportional servo valve operates in the left position or the right position respectively, driving the actuator to overcome the damping-spring-guide rail load simulation unit, thereby reproducing the actual working state of the aviation hydraulic plunger pump when the wing on the aircraft is actuated.

[0088] It should be noted that by adjusting the openings of any two of the third proportional speed control valve, the fourth proportional speed control valve, and the second proportional relief valve, throttling or overflowing loads can be simulated as needed. This flexible adjustment of load types allows the system to adapt to different fault and operating scenarios. By simultaneously adjusting the openings of these three components, complex throttling and overflowing loads can be simulated, which is important for verifying the performance and durability of the system. It should also be noted that specific failure modes and load types can be freely combined according to actual needs.

[0089] S204 , obtaining normal working state data and faulty working state data according to the simulation scheme, comparing the two types of data, and extracting time-frequency domain fault characteristic parameters.

[0090] It should be noted that the simulation scheme records key parameters of each system component, including pressure, flow, temperature, and displacement, while the hydraulic system is operating normally. A fault mode injection system is used to simulate different types of faults, such as structural failure, cavitation, oil return blockage, or excessive contaminants. Under these simulated fault conditions, the same system component parameters as under normal operating conditions are recorded. Furthermore, by comparing the time and frequency domain feature parameters extracted under normal and fault conditions, the fault characteristics present in the system can be determined.

[0091] The hydraulic method for injecting fault modes into an aviation hydraulic plunger pump, provided in this embodiment, can simulate a variety of fault modes, including structural failure, cavitation failure, oil return blockage, and excessive contaminants, by designing a complex hydraulic simulation system and fault injection mechanism. Furthermore, for each fault type, there are corresponding methods for determining the fault mechanism, the affected system components, and the simulation scheme, enabling more realistic simulation of various possible fault conditions that may occur in actual use of the aviation hydraulic plunger pump. When determining the system components affected by the current state test, the fault tree model corresponding to the test state type is obtained, and the affected components are determined based on the component connection status and hydraulic oil flow state. This facilitates a more systematic analysis of potential problems in the hydraulic system and can identify the specific fault location and type. Furthermore, by obtaining normal working state data and fault working state data and comparing the two types of data to extract time-frequency domain fault feature parameters, it can provide an accurate basis for fault diagnosis of the aviation hydraulic plunger pump. This feature extraction method based on actual simulation test data better reflects the actual situation than traditional methods based on simulation models and mathematical models, improving the accuracy and reliability of fault diagnosis.

[0092] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. An aviation hydraulic plunger pump failure mode injection simulation hydraulic system, characterized in that: The hydraulic system comprises: An aviation hydraulic plunger pump, wherein the oil inlet of the aviation hydraulic plunger pump is connected to the low-pressure oil port of the first proportional speed regulating valve and a fault injector, and is connected to the self-pressurizing oil tank via the high-pressure oil port of the first proportional speed regulating valve, and the fault injector is used to inject contaminants; the oil return port of the aviation hydraulic plunger pump is connected to the self-pressurizing oil tank via the low-pressure oil port of the first proportional relief valve; A two-position three-way reversing valve, wherein the oil outlet of the aviation hydraulic plunger pump is connected to the inlet of the two-position three-way reversing valve, the first outlet of the two-position three-way reversing valve is connected to the simulated load branch, and the second outlet of the two-position three-way reversing valve is connected to the reproducing branch of the wing actuation working condition on the aircraft; The simulated load branch is provided with a third proportional speed regulating valve, a second proportional relief valve and a fourth proportional speed regulating valve, the first outlet of the two-position three-way reversing valve is connected to the high-pressure oil port of the third proportional speed regulating valve, and the low-pressure oil port of the third proportional speed regulating valve is simultaneously connected to the high-pressure oil port of the fourth proportional speed regulating valve and the high-pressure oil port of the second proportional relief valve; The reproduction branch is provided with a three-position four-way proportional servo valve and an actuator cylinder. The second outlet of the two-position three-way reversing valve is connected to the first inlet of the three-position four-way proportional servo valve, and is connected to the actuator cylinder through the first outlet of the three-position four-way proportional servo valve. The actuator cylinder is connected to the damping-spring-guide rail load simulation unit.

2. The system according to claim 1, wherein: The system further comprises: The first servo motor is connected to the aviation hydraulic plunger pump, the oil outlet of the aviation hydraulic plunger pump is connected to the seventh pressure and temperature sensor, and after flowing through the contamination sensor, is connected to the oil inlet of the one-way valve; The oil outlet of the one-way valve is connected to the high-pressure oil port of the third filter; the low-pressure oil port of the third filter is connected to the high-pressure oil port of the second flow meter; the low-pressure oil port of the second flow meter is simultaneously connected to the oil inlet and outlet of the accumulator, the solenoid switch valve, and the high-pressure oil port of the second proportional speed regulating valve; the low-pressure oil port of the second proportional speed regulating valve is connected to the inlet of the two-position three-way reversing valve; The simulated load branch further includes: The first outlet of the two-position three-way reversing valve is connected to the first pressure and temperature sensor, the low-pressure oil port of the fourth proportional speed control valve and the low-pressure oil port of the second proportional relief valve are simultaneously connected to the high-pressure oil port of the third proportional relief valve, the second pressure and temperature sensor, and the high-pressure oil port of the fourth filter, and the low-pressure oil port of the third proportional relief valve and the low-pressure oil port of the fourth filter are connected to the self-pressurized oil tank.

3. The system according to claim 1, wherein: The reproduction branch of the on-board wing actuation working condition also includes: the second outlet of the two-position three-way reversing valve is connected to the high-pressure oil port of the fifth proportional speed control valve, and the low-pressure oil port of the fifth proportional speed control valve is simultaneously connected to the ninth pressure and temperature sensor and the first inlet of the three-position four-way proportional servo valve; the first outlet of the three-position four-way proportional servo valve is connected to the first inlet of the hydraulic lock, and the first outlet of the hydraulic lock is simultaneously connected to the third pressure and temperature sensor and the rodless cavity of the actuator cylinder; the rod cavity of the actuator cylinder is simultaneously connected to the fourth pressure and temperature sensor and the second inlet of the hydraulic lock, and the second outlet of the hydraulic lock is connected to the second inlet of the three-position four-way proportional servo valve; the second outlet of the three-position four-way proportional servo valve is simultaneously connected to the fifth pressure and temperature sensor and the high-pressure oil port of the fifth filter, and the low-pressure oil port of the fifth filter is connected to the self-pressurizing oil tank.

4. The system according to claim 2, wherein: The system further comprises: The oil return port of the aviation hydraulic plunger pump passes through the high-pressure oil port and the low-pressure oil port of the first filter, flows through the high-pressure oil port and the low-pressure oil port of the first flow meter, and is connected to the high-pressure oil port of the first proportional relief valve. The eighth pressure and temperature sensor is connected to the high-pressure oil port of the first filter; The contamination sensor is connected to the oil inlet of the unloading valve and the oil inlet of the safety valve; the oil outlet of the unloading valve and the oil outlet of the safety valve are connected to the self-pressurizing oil tank.

5. The system according to claim 1, wherein: The system comprises: The second servo motor is connected to the quantitative gear pump, and the oil inlet of the quantitative gear pump draws hydraulic oil from the self-pressurized oil tank through the oil inlet and oil return port of the second filter; The oil outlet of the quantitative gear pump flows through the oil inlet and return port of the radiator and flows back to the self-pressurized oil tank; The sixth pressure and temperature sensor is connected to the self-pressurizing fuel tank.

6. A method for injecting a simulated hydraulic pressure into a failure mode of an aviation hydraulic plunger pump, the simulated hydraulic pressure method being applied to a hydraulic system according to any one of claims 1 to 5, characterized in that: The simulated hydraulic method comprises: Obtaining the current test state type, where the test state type includes a normal working state test and a fault working state test; Determine the failure mechanism of the test state type and obtain the system components affected by the current state test; Determining a simulation scheme based on the affected system components, the simulation scheme including a normal state adjustment mode and a fault state adjustment mode; According to the simulation scheme, normal working state data and fault working state data are obtained, and the two types of data are compared to extract time-frequency domain fault characteristic parameters.

7. The method according to claim 6, characterized in that Determine the failure mechanism of the test state type and obtain the system components affected by the current state test, including: Obtain the fault tree model corresponding to the test state type; Determine the connection status of each system component and the flow status of hydraulic oil based on the fault tree model; The system components affected by the current state test are determined based on the connection state and the hydraulic oil flow state.

8. The method according to claim 6, characterized in that Determine simulation scenarios based on the impacted system components, including: Identifying the normal state and the corresponding fault mode of the affected system components, and determining the type of fault occurring in the component based on the fault mode; the fault types include structural failure, cavitation failure, oil return blockage, and excessive pollutants; Adjust system components based on identified normal states and failure modes; A simulation scenario is generated based on the adjusted system status.

9. The method according to claim 8, characterized in that The adjusting of system components based on the identified normal state and failure mode includes: In normal state, adjust the corresponding relief valve and speed regulating valve; When the fault type is structural failure, the aircraft hydraulic plunger pump being tested is disassembled, and normal parts in the aircraft hydraulic plunger pump are replaced with faulty parts to perform a fault injection test to obtain performance and vibration characteristic test data under the fault state; When the fault type is a cavitation fault, adjusting the valve core opening of the first proportional speed control valve to simulate a cavitation fault at the oil inlet of an aviation hydraulic plunger pump; When the fault type is oil return blockage, the overflow pressure of the first proportional relief valve is adjusted to simulate the oil return pressure under different blockage conditions, and the pressure and flow of the oil return port of the aviation hydraulic plunger pump are monitored in real time through the first flow meter and the eighth pressure and temperature sensor; When the fault type is excessive pollutants, pollutants are injected into the oil circuit through a fault injector to directly simulate the fault mode of excessive pollutants in the oil suction pipeline of the aviation hydraulic plunger pump, and filters are connected to the oil outlet and return port of the aviation hydraulic plunger pump.

10. The method according to claim 6, characterized in that The simulation scheme includes: When the two-position three-way valve is reversed, the reversing path is determined according to the working conditions; when the reversing path is in the left position, by adjusting the opening of any two components among the third proportional speed regulating valve, the fourth proportional speed regulating valve and the second proportional relief valve, a throttling load or a relief load is simulated, and by adjusting the opening of the three components at the same time, a throttling-relief load is simulated; When the reversing path is in the right position, the three-position four-way proportional servo valve operates in the left position or the right position respectively, driving the actuator to overcome the damping-spring-guide rail load simulation unit, thereby reproducing the actual working state of the aviation hydraulic plunger pump when the wing on the aircraft is actuated.

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