High-safety array landing gear retraction and steering valve and fault-tolerant method

Abstract

The application belongs to the technical field of aircraft landing gear retraction system, and particularly relates to a high-safety array type landing gear retraction reversing valve and a fault-tolerant method thereof. The reversing valve comprises a main valve, a first pilot control stage, a second pilot control stage, a first pressure sensor and a second pressure sensor; wherein each pilot control stage is composed of a valve group and a damping hole, the valve group comprises at least three two-position two-normal-closed electromagnetic on-off valves arranged in parallel, the outlets of the electromagnetic on-off valves are connected to an oil return port, and the damping hole is connected in series between an oil inlet and the inlets of the electromagnetic on-off valves. The application sets the pilot stage hydraulic half-bridge composed of multiple electromagnetic on-off valves and damping holes at both ends of the main valve, and adopts a grouping control strategy to realize accurate adjustment of the pressure of the control cavities at both ends of the main valve core. In combination with the intelligent diagnosis based on real-time pressure feedback and the multi-stage fault-tolerant control method, the reliability, safety and intelligent level of the landing gear retraction reversing valve are significantly improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aircraft landing gear retraction system, and particularly relates to a high-safety array type landing gear retraction directional valve and a fault-tolerant method. BACKGROUND

[0002] The aircraft landing gear retraction system is a key system for ensuring the safe take-off and landing of an aircraft, and a core control element thereof is a landing gear retraction directional valve. In the prior art, the landing gear retraction directional valve usually adopts a pilot control mode, that is, the movement of a main valve core is controlled by a small-power two-position three-way pilot electromagnetic valve to realize the rapid switching and locking of a large-flow high-pressure oil circuit, so as to drive the landing gear to retract, extend and keep in a locked state. The above technical route is a key link for the flight control system to realize the physical layer of "fly-by-wire" control.

[0003] In some common designs, the movement of each end of the main valve core is controlled by a single pilot electromagnetic valve. The inherent defect of this design is that the pilot electromagnetic valve constitutes a single-point fault source of the system. Once the pilot electromagnetic valve fails due to mechanical jamming, coil burning or oil path blockage, etc., the main valve core will not be able to change direction as instructed, thereby causing the entire landing gear retraction function to be paralyzed, which poses a serious threat to flight safety. In addition, such a traditional system usually lacks real-time monitoring capability of the working state of the pilot control stage, cannot effectively diagnose and isolate faults when they occur, and has no intelligent fault-tolerant mechanism for function compensation or degraded operation in the fault mode. SUMMARY

[0004] The application provides a high-safety array type landing gear retraction directional valve and a fault-tolerant method to solve the above problems and significantly improve the reliability and safety of the system, aiming at the technical defects in the prior art that the pilot control stage of the landing gear retraction directional valve has a single-point fault risk and lacks real-time monitoring and intelligent fault-tolerant capability.

[0005] The first aspect of the application is to provide a high-safety array type landing gear retraction directional valve, which comprises a main valve having a first control cavity and a second control cavity for driving the directional change thereof, a first pilot control stage and a second pilot control stage connected with the first control cavity and the second control cavity respectively, and a first pressure sensor and a second pressure sensor for monitoring the pressure of the first control cavity and the second control cavity respectively.

[0006] The first pilot control stage and the second pilot control stage each comprise:

[0007] The valve group comprises at least three electromagnetic on-off valves arranged in parallel, the inlet of each electromagnetic on-off valve of the first pilot control stage is connected with the first control cavity, the inlet of each electromagnetic on-off valve of the second pilot control stage is connected with the second control cavity, and the outlet of each electromagnetic on-off valve of the first pilot control stage and the second pilot control stage is connected to the oil return port.

[0008] The damping hole is connected in series between the oil inlet and the inlet of each electromagnetic on-off valve, and oil enters the first control cavity and the second control cavity through the oil inlet and the damping hole.

[0009] Further, the valve group is composed of three electromagnetic on-off valves arranged in parallel, and each electromagnetic on-off valve is in a power-off closed state, the pressure of the first control cavity and the second control cavity of the main valve is balanced, and the main valve remains in the neutral position, and the landing gear is in a safe floating mode.

[0010] Further, the electromagnetic on-off valve is a two-position two-way electromagnetic on-off valve.

[0011] The second aspect of the present application is to provide a fault-tolerant method of a high-safety array landing gear extension / retraction reversing valve, comprising the following steps:

[0012] Upon receiving a command for driving the main valve to reverse, defining the pilot control stage corresponding to the command as a target-side pilot control stage, and defining the other pilot control stage as a non-target-side pilot control stage;

[0013] Sending an opening command to at least two electromagnetic on-off valves in the valve group of the target-side pilot control stage, and sending a closing command to the electromagnetic on-off valves of the other target-side pilot control stage and the non-target-side pilot control stage, so as to depressurize the control cavity corresponding to the target-side pilot control stage, and form a pressure difference between the first control cavity and the second control cavity of the main valve for driving the main valve to reverse;

[0014] Based on the pressure information obtained by the first pressure sensor or the second pressure sensor, the execution of the opening / closing command is judged, when it is monitored that the pressure of the control cavity corresponding to the target-side pilot control stage does not change according to the preset logic, it is diagnosed that there is a fault in the electromagnetic on-off valve, and the opening / closing state of the other electromagnetic on-off valves in the valve group of the target-side pilot control stage and / or the non-target-side pilot control stage is dynamically adjusted to compensate for the pressure change caused by the fault, so as to ensure that the main valve can still reverse or remain in the neutral position.

[0015] Optionally, the valve group is composed of three electromagnetic on-off valves arranged in parallel, in the normal working mode, the step of sending an opening command to the valve group of the target-side pilot control stage comprises: adopting a "two out of three" control logic to open any two of the three electromagnetic on-off valves.

[0016] Optionally, it is diagnosed that there is an electromagnetic switch valve fault, specifically, it is diagnosed that a certain electromagnetic switch valve in the valve group of the target side pilot control stage has a "power-on failure to open" fault;

[0017] When it is necessary to drive the main valve to reverse, the specific steps of dynamic adjustment are to open the electromagnetic switch valves other than the fault valve in the valve group of the target side pilot control stage.

[0018] Optionally, it is diagnosed that there is an electromagnetic switch valve fault, specifically, it is diagnosed that a certain electromagnetic switch valve in the valve group of the non-target side pilot control stage has a "power-off failure to close" fault;

[0019] When it is necessary to drive the main valve to reverse, the specific steps of dynamic adjustment are to open all three electromagnetic switch valves in the valve group of the target side pilot control stage.

[0020] Optionally, it is diagnosed that there is an electromagnetic switch valve fault, specifically, it is diagnosed that a certain electromagnetic switch valve in the valve group of the target side pilot control stage and the non-target side pilot control stage has a "power-off failure to close" fault;

[0021] When it is necessary to drive the main valve to reverse, the specific steps of dynamic adjustment are to open the electromagnetic switch valves other than the fault valve in the valve group of the target side pilot control stage.

[0022] Optionally, it is diagnosed that there is an electromagnetic switch valve fault, specifically, it is diagnosed that two electromagnetic switch valves in the valve group of the target side pilot control stage or the non-target side pilot control stage have faults;

[0023] When it is diagnosed that two electromagnetic switch valves in the valve group of the target side pilot control stage have "power-on failure to open" faults, the specific steps of dynamic adjustment are to make all the electromagnetic switch valves in the valve group of the target side pilot control stage and the valve group of the non-target side pilot control stage be in a power-off state, and make the main valve remain in the middle position.

[0024] When it is diagnosed that two electromagnetic switch valves in the valve group of the non-target side pilot control stage have "power-off failure to close" faults, the specific steps of dynamic adjustment are to open any two electromagnetic switch valves in the valve group of the target side pilot control stage to be powered on, and make the main valve remain in the middle position.

[0025] Optionally, the step of judging the execution of the opening instruction based on the pressure information obtained by the first pressure sensor and the second pressure sensor is specifically:

[0026] The actual pressure change monitored by the first pressure sensor and the second pressure sensor is compared with a preset pressure change threshold or a preset pressure change curve to judge whether the pressure of the control chamber corresponding to the target side pilot control stage changes according to the preset logic.

[0027] Compared with the prior art, the application has the following advantages:

[0028] (1) The application completely eliminates the risk of single-point failure of the traditional pilot valve by using a redundant array composed of three parallel electromagnetic on-off valves in the first control chamber and the second control chamber of the main valve. Even if one of the electromagnetic on-off valves fails, the system can still complete the reversing function by calling other healthy electromagnetic on-off valves, ensuring the normal execution of the landing gear retraction task.

[0029] (2) The application monitors the working state of the electromagnetic on-off valve in real time online through the first pressure sensor and the second pressure sensor, accurately diagnoses the failure, and actively executes the compensation control strategy according to the diagnosis result, dynamically adjusts the oil circuit, and ensures that sufficient driving force can still be generated in the case of failure, realizing the mode change from "failure-paralysis" to "failure-operation".

[0030] (3) In the extreme case of multiple electromagnetic on-off valves failing simultaneously, which cannot be recovered by the fault-tolerant strategy, the application can still identify the failure through dynamic adjustment and make all the electromagnetic on-off valves in a safe state, ensuring that the main valve is locked in the middle position and preventing the landing gear from moving unexpectedly, thereby enhancing the safety protection of the system. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0032] Figure 1 The hydraulic principle diagram of the landing gear retraction reversing valve provided by the embodiment of the application;

[0033] Figure 2 The oil circuit schematic diagram of the landing gear retraction reversing valve provided by the embodiment of the application in the normal working mode;

[0034] Figure 3 The oil circuit schematic diagram of the landing gear retraction reversing valve provided by the embodiment of the application in the "power-on but not open" failure mode;

[0035] Figure 4 The oil circuit schematic diagram of the landing gear retraction reversing valve provided by the embodiment of the application in the "power-off but not closed" failure mode;

[0036] Figure 5 The flowchart of the fault-tolerant method provided by the embodiment of the application.

[0037] Wherein: 1-Solenoid valve one; 2-Solenoid valve two; 3-Solenoid valve three; 4-Solenoid valve four; 5-Solenoid valve five; 6-Solenoid valve six; 7-First spring; 8-Second spring; 10-Main valve; 11-First control chamber; 12-Second control chamber; 21-First pilot control stage; 22-Second pilot control stage; 31-First pressure sensor; 32-Second pressure sensor; 41-Damping orifice one; 42-Damping orifice two; 50-Landing gear retraction and extension actuator; P-Oil inlet; T-Oil return port; A, B-Control oil ports. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0039] The following is in conjunction with the appendix Figure 1 To be continued Figure 5 The invention is described in detail with specific embodiments.

[0040] See Figure 1 This application provides a high-safety array-type landing gear retraction and extension directional valve, including a main valve 10. The main valve 10 has a first control chamber 11 and a second control chamber 12 for driving its retraction. It also includes a first pilot control stage 21 and a second pilot control stage 22 connected to the first control chamber 11 and the second control chamber 12, respectively, and a first pressure sensor 31 and a second pressure sensor 32 for monitoring the pressure of the first control chamber 11 and the second control chamber 12, respectively. A first spring 7 is provided in the first control chamber 11, and a second spring 8 is provided in the second control chamber 12. Both the first spring 7 and the second spring 8 are return springs and maintain a preset compression amount. When the pressure of the first control chamber 11 and the second control chamber 12 at both ends of the main valve core is balanced, the first spring 7 and the second spring 8 generate equal centering forces. The directional valve is hydraulically connected to a load (such as the landing gear retraction and extension actuator 50) through control ports A and B. The entire system is provided with a system pressure inlet P and a return port T.

[0041] Specifically, the main valve 10 is a three-position four-way directional valve, which contains a movable main valve core. The position of the main valve core determines the connection between the inlet port P and the return port T in the main oil circuit and the control ports A and B. In this embodiment, the main valve 10 has three operating positions: a neutral position for placing the landing gear in a safe floating mode, and operating positions for retracting and extending the landing gear (the directions of retracting and extending the landing gear are indicated as follows). Figure 1as shown).

[0042] As a preferred embodiment, the first pilot control stage 21 and the second pilot control stage 22 are arranged in mirror symmetry in structure and function, respectively for controlling the pressure of the first control chamber 11 and the second control chamber 12, and by establishing a pressure difference between the two control chambers, the main valve spool is driven to move axially, thereby realizing the reversing function. For the convenience of description, the first pilot control stage 21 is taken as an example, which includes a lower end electromagnetic on-off valve group and a damping hole one 41 connected in series with the valve group. The lower end electromagnetic on-off valve group includes three electromagnetic on-off valves one 1, two 2 and three 3 arranged in parallel. As a preferred embodiment, the electromagnetic on-off valves are all two-position two-way normally closed electromagnetic on-off valves, wherein "two-position two-way" means that each electromagnetic on-off valve has two oil ports and two working positions (open position and closed position), and "normally closed" means that in the initial state when the electromagnetic coil is not energized, the valve is in the closed position, and the two oil ports are not connected. The inlets of the above-mentioned electromagnetic on-off valves one 1, two 2 and three 3 are connected in parallel and connected to the first control chamber 11, and the outlets are connected to the oil return port T. It should be noted that the normally closed characteristic of the electromagnetic on-off valve is the safety basis for realizing the system work.

[0043] The damping hole one 41 is a hydraulic element with a fixed orifice diameter, which is connected in series between the oil inlet port P and the common inlet of the first control chamber 11 and the lower end electromagnetic on-off valve group, and the oil enters the first control chamber 11 through the oil inlet port P and the damping hole one 41. The damping hole one 41 and the lower end electromagnetic on-off valve group together constitute a hydraulic half-bridge structure, which is the key to accurately control the pressure of the first control chamber 11, and the damping hole one 41 functions to limit the flow of hydraulic oil flowing from the oil inlet port P into the first control chamber 11.

[0044] Correspondingly, the second pilot control stage 22 includes a upper end electromagnetic on-off valve group and a damping hole two 42. The upper end electromagnetic on-off valve group is composed of three parallel two-position two-way normally closed electromagnetic on-off valves four 4, five 5 and six 6. The inlets of the electromagnetic on-off valves four 4, five 5 and six 6 are connected in parallel and are commonly connected to the second control chamber 12, and the outlets are commonly connected to the oil return port T. The damping hole two 42 is connected in series between the system oil inlet port P and the common inlet of the second control chamber 12 and the upper end electromagnetic on-off valve group, and the oil enters the first control chamber 11 through the oil inlet port P and the damping hole two 42.

[0045] The first pressure sensor 31 and the second pressure sensor 32 are respectively installed in the oil lines connecting the first control chamber 11 and the second control chamber 12. Their function is to monitor and collect the hydraulic oil pressure values ​​in the first control chamber 11 and the second control chamber 12 in real time and continuously, and convert these pressure signals into electrical signals and feed them back to the external controller (not shown in the figure). These real-time pressure data form the basis for realizing system status monitoring, fault diagnosis and intelligent fault-tolerant control.

[0046] The following is in conjunction with the appendix Figure 1 and attached Figure 2 The movement process of the reversing valve in normal operating mode is described.

[0047] like Figure 1 As shown, when the landing gear is in safe floating mode (i.e., the landing gear is stationary or in a standby state), the controller does not issue any action commands, and all six solenoid valves (soleoid valve 1 to solenoid valve 6) are de-energized. Since they are all normally closed valves, they are all in the closed position. At this time, pressurized oil from the aircraft hydraulic system enters the reversing valve through the inlet P. One path of oil passes through damping orifice 41 to pressurize the first control chamber 11; the other path passes through the corresponding damping orifice 42 to pressurize the second control chamber 12. Since the two first pilot control stages 21 and the second pilot control stage 22 are symmetrical, and all drain channels (soleoid valve 1 to solenoid valve 6) are closed, the pressure in the first control chamber 11 and the second control chamber 12 will eventually reach equilibrium with the system pressure at the inlet P, and the first spring 7 and the second spring 8 will generate equal centering forces. At this time, the main valve core of the main valve 10 is stably maintained in the middle position under the balanced hydraulic pressure at both ends and the action of the springs. In this neutral position, the internal oil circuit design of the main valve 10 ensures that both control ports A and B are connected to the return port T. In other words, neither chamber of the landing gear retraction actuator is subjected to high pressure, and the landing gear is in a safe floating or locked state.

[0048] like Figure 2 As shown, when a "landing gear lowering" command is required, the controller receives the command and, according to preset control logic, defines the first pilot control level 21 corresponding to the "lowering" action as the "target-side pilot control level" and the second pilot control level 22 as the "non-target-side pilot control level." Subsequently, the controller executes the drive strategy under normal operating conditions, i.e., the "two-out-of-three" control logic. Specifically, the controller selects any two of the three solenoid valves (sole valves one, two, and three) from the lowering-end solenoid valve assembly and sends an energizing opening command to their solenoid coils. The other solenoid valves that have not received an opening command remain closed. For example, in... Figure 2In the illustrated example, the controller selects to open electromagnetic switch valve two 2 and electromagnetic switch valve three 3. When the coils of electromagnetic switch valve two 2 and electromagnetic switch valve three 3 are energized, their internal spools actuate to switch the valves from their normally closed position to their open position. As a result, a high flow drain path is created between the first control chamber 11 and the tank T through the two parallel open electromagnetic switch valves. The pressure in the first control chamber 11 drops rapidly, and at the same time, all the electromagnetic switch valves (four, five, six) in the non-target side of the second pilot control stage 22 remain de-energized and closed. Therefore, the pressure in the second control chamber 12 remains connected to the inlet P through the damping orifice two 42, and the pressure value is maintained at a high level. Thus, a significant pressure difference is established across the main spool of the main valve 10: the second control chamber 12 is high pressure, and the first control chamber 11 is low pressure. This pressure difference acts on the effective area of the main spool, generating a strong hydraulic thrust from right to left. When this thrust exceeds the pre-tightening force of the spring and the frictional resistance of the spool movement, the main spool begins to move to the left until it reaches its left working position.

[0049] When the main spool of the main valve 10 moves to the left working position, the internal main oil passage is switched. As shown by the oil passage in Figure 2 , the inlet P of the system is connected to the control port A, and the control port B is connected to the tank T. High pressure oil flows out from the inlet P, enters the control port A through the main valve 10, and then enters the rod chamber of the landing gear retraction actuator 50, pushing the piston of the landing gear retraction actuator 50 to move towards the rodless chamber. At the same time, the oil in the rodless chamber of the landing gear retraction actuator 50 is discharged back to the tank T through the control port B and the main valve 10, thereby driving the landing gear to perform the lowering action.

[0050] Throughout the process, the first pressure sensor 31 and the second pressure sensor 32 continuously monitor and feedback the pressure changes of the two control chambers to the controller. The controller can confirm whether the reversing command is successfully executed according to whether the pressure in the first control chamber 11 drops rapidly below the preset threshold value and whether the pressure in the second control chamber 12 remains stable.

[0051] Correspondingly, when the "landing gear retract" command needs to be executed, the controller takes the second pilot control stage 22 as the target side pilot control stage and opens any two electromagnetic switch valves (e.g., electromagnetic switch valve four 4 and electromagnetic switch valve five 5) in the retracting end electromagnetic switch valve group using the "two out of three" logic. This will cause the second control chamber 12 to be depressurized, while maintaining high pressure in the first control chamber 11, thereby generating a thrust from left to right to drive the main spool of the main valve 10 to move to the right. After the main spool reaches the right working position, it will connect the P-B and A-T oil passages, driving the landing gear retraction actuator 50 to perform the retracting action.

[0052] Through the above structure and control method, the commutation valve provided by the embodiment can complete commutation by using only two electromagnetic commutation valves in each valve group in normal operation, and one is reserved as a backup, thereby laying a foundation for fault tolerance. The "two out of three" design itself embodies the redundancy idea and improves the reliability of the system.

[0053] Referring to Figures 3 to 5 The application also provides a fault-tolerant method for the high-safety array landing gear retraction and commutation valve, which comprises the following steps:

[0054] S101: receiving a commutation instruction; specifically, when receiving an instruction for driving the main valve 10 to commutate, defining the pilot control stage corresponding to the instruction as a target side pilot control stage, and defining the other pilot control stage as a non-target side pilot control stage; sending an opening instruction to at least two electromagnetic on-off valves in the valve group of the target side pilot control stage, and sending a closing instruction to the electromagnetic on-off valves of the other target side pilot control stage and the non-target side pilot control stage, so as to depressurize the control cavity corresponding to the target side pilot control stage, and form a pressure difference for driving the main valve 10 to commutate between the first control cavity 11 and the second control cavity 12 of the main valve 10; it can be understood that in the initial state without any electromagnetic valve failure, all the electromagnetic on-off valves are in the closed state, that is, the electromagnetic on-off valves that have not received the opening instruction are in the closed state.

[0055] S102: executing a "two out of three" control logic; specifically, opening any two of the valve groups of the target side pilot control stage;

[0056] S103: monitoring pressure changes; specifically, acquiring pressure information of the first control cavity 11 and the second control cavity 12 of the main valve in real time through the first pressure sensor 31 and the second pressure sensor 32;

[0057] S104: judging whether the pressure meets the standard; specifically, after sending the opening instruction, judging the execution of the opening instruction based on the pressure information acquired by the first pressure sensor 31 or the second pressure sensor 32; when it is monitored that the pressure meets the expected standard, the commutation is successful; when it is monitored that the pressure of the control cavity corresponding to the target side pilot control stage does not change according to the preset logic, it is diagnosed that there is an electromagnetic on-off valve failure;

[0058] S105: diagnosing the fault type and judging whether it can be fault-tolerant; when it can be fault-tolerant, executing step S106; when it cannot be fault-tolerant, executing step S107;

[0059] S106: executing a corresponding fault-tolerant strategy; specifically, dynamically adjusting the opening and closing states of the other electromagnetic on-off valves of the target side pilot control stage valve group and / or the non-target side pilot control stage valve group, so as to compensate for the pressure change caused by the failure and ensure that the main valve 10 can still commutate, and the commutation is successful;

[0060] S107: executing a safety lock mode; specifically, dynamically adjusting the on-off state of the other solenoid valves in the target-side pilot control stage valve group and / or the non-target-side pilot control stage valve group, so that the main valve 10 is locked in the neutral position.

[0061] In some embodiments, as in step S104, it is diagnosed that there is a solenoid valve fault, specifically, it is diagnosed that a solenoid valve in the valve group of the target-side pilot control stage has a "power-on failure to open" fault; for example, referring to Figure 3 , the solenoid valve one 1 has a "power-on failure to open" fault, which means that even if the controller sends a power-on command to it, the solenoid valve one 1 cannot open and always remains closed. By monitoring the simultaneous opening of the fault solenoid valve and the solenoid valve two 2 or the solenoid valve three 3 with the first pressure sensor 31, the pressure in the first control chamber 11 has not yet dropped to the switching threshold, and it is determined that the solenoid valve one 1 has a "power-on failure to open" fault.

[0062] When it is necessary to drive the main valve 10 to switch, in step S106, the specific steps of dynamic adjustment are: opening the other solenoid valves in the target-side pilot control stage valve group except the fault valve, that is, the control system immediately activates the solenoid valve two 2 and the solenoid valve three 3 of the lower end solenoid valve group, and the two solenoid valves are synchronously opened to form a parallel unloading path. Due to the throttling effect of the damping hole one 41, the pressure in the first control chamber 11 rapidly drops below the switching pressure threshold, and the pressure difference across the main valve spool causes the hydraulic pressure difference to exceed the pre-tightening force of the return spring. The main valve spool completes the specified displacement, realizes oil path switching, the oil inlet P is connected with the control oil port A, high-pressure oil enters the rod chamber of the landing gear retraction actuator 50, the oil return port T is connected with the control oil port B, and the rod chamber is depressurized, and then the landing gear is lowered.

[0063] In other embodiments, referring to Figure 4 , as in step S104, it is diagnosed that there is a solenoid valve fault, specifically, it is diagnosed that a solenoid valve in the valve group of the non-target-side pilot control stage has a "power-off failure to close" fault; for example, the solenoid valve four 4 in the upper end solenoid valve group has a power-off failure to close fault, and by monitoring the pressure decrease in the second control chamber 12 with the second pressure sensor 32, independent power-on and power-off tests are performed on the solenoid valve four 4, the solenoid valve five 5 and the solenoid valve six 6 respectively. Only when the solenoid valve four 4 is powered on and off, the pressure in the second control chamber 12 does not respond, it is determined that the solenoid valve four 4 has a "power-off failure to close" fault. The fault performance is that the valve cannot reset and close after the solenoid is powered off or the closing position leakage increases, which may be caused by the fact that the mover / valve spool cannot reset and cut off the oil path due to jamming or sealing failure.

[0064] When the landing gear needs to be lowered, the corresponding fault-tolerant strategy is executed (step S106), specifically, the control system immediately activates the electromagnetic switch valve group of the lowering end, i.e., electromagnetic switch valve one 1, electromagnetic switch valve two 2, and electromagnetic switch valve three 3, the three electromagnetic switch valves are synchronously opened to form a parallel unloading path, due to the throttling effect of the damping hole one 41, the pressure of the first control chamber 11 rapidly decreases to below the switching pressure threshold, the pressure difference between the two ends of the main valve core causes the hydraulic pressure difference between the two ends to exceed the pre-tightening force of the return spring. The main valve core completes the specified stroke displacement, the oil circuit is switched, the oil inlet P is connected to the control oil port A, high-pressure oil enters the landing gear retraction and deployment cylinder 50, the oil return port T is connected to the control oil port B, the rodless chamber is depressurized, and then the landing gear is lowered.

[0065] In some embodiments, as in step S104, it is diagnosed that there is an electromagnetic switch valve failure, specifically, it is diagnosed that both electromagnetic switch valves in the target side pilot control stage and the non-target side pilot control stage valve group have failed; taking the simultaneous failure of the lowering end electromagnetic switch valve group electromagnetic switch valve one 1 and the retraction end electromagnetic switch valve group electromagnetic switch valve four 4 as an example; if electromagnetic switch valve one 1 fails to close due to power failure, and electromagnetic switch valve four 4 fails to close due to power failure, the corresponding fault-tolerant strategy (step S106) is executed, electromagnetic switch valve two 2 and electromagnetic switch valve three 3 are simultaneously powered on, and the landing gear can perform the lowering action. If electromagnetic switch valve one 1 fails to open due to power failure, and electromagnetic switch valve four 4 fails to close due to power failure, the landing gear cannot perform the lowering function, at this time, the safety locking mode (step S107) is executed, electromagnetic switch valve two 2 or electromagnetic switch valve three 3 is opened to ensure that the control chamber pressures on both sides of the main valve 10 are equal, preventing the landing gear from malfunctioning.

[0066] In some embodiments, in step S105, it is diagnosed that there is an electromagnetic switch valve failure, specifically, it is diagnosed that both electromagnetic switch valves in the target side pilot control stage or the non-target side pilot control stage valve group have failed;

[0067] When it is diagnosed that both electromagnetic switch valves in the target side pilot control stage valve group have a "power failure cannot open" failure, the safety locking mode (S107) is executed: all electromagnetic switch valves in the target side pilot control stage valve group and the non-target side pilot control stage valve group are in a power-off state, the main valve 10 is kept in the middle position, preventing the landing gear from malfunctioning;

[0068] When it is diagnosed that both electromagnetic switch valves in the non-target side pilot control stage valve group have a "power failure cannot close" failure, such as electromagnetic switch valve four 4 and electromagnetic switch valve five 5, the safety locking mode (S107) is executed: any two electromagnetic switch valves in the target side pilot control stage valve group are powered on, the main valve is kept in the middle position, preventing the landing gear from malfunctioning.

[0069] The embodiment shows the final security layer of the scheme, in the case that the redundancy and fault-tolerant strategy cannot overcome the extreme failure, the system will not lose control, but can autonomously enter a predefined, absolutely safe locking state, reduces the system risk to the minimum, fully embodies the design concept of "fail-safe".

[0070] In summary, the application greatly improves the reliability, safety and intelligent level of the landing gear extension / retraction reversing valve by adopting the array type redundant pilot valve group structure, and combining the intelligent diagnosis based on real-time pressure feedback and multi-level fault-tolerant control method.

[0071] The above further describes the application by means of specific embodiments, but it should be understood that the specific description herein should not be understood as limiting the essence and scope of the application, and various modifications made by those skilled in the art to the above embodiments after reading the specification all belong to the scope protected by the application.

Claims

1. A fault-tolerant method for a high-safety arrayed landing gear retraction / slew valve, characterized in that, The high-safety array landing gear retraction and steering valve comprises a main valve having a first control chamber and a second control chamber for driving the steering thereof, characterized in that it further comprises a first pilot control stage and a second pilot control stage connected with the first control chamber and the second control chamber respectively, and a first pressure sensor and a second pressure sensor for monitoring the pressure of the first control chamber and the second control chamber respectively; The first pilot control stage and the second pilot control stage each comprise: a valve group comprising at least three electromagnetic on-off valves arranged in parallel, the inlet of each electromagnetic on-off valve of the first pilot control stage being connected with the first control chamber, the inlet of each electromagnetic on-off valve of the second pilot control stage being connected with the second control chamber, and the outlet of each electromagnetic on-off valve of the first pilot control stage and the second pilot control stage being connected to an oil return port; a damping hole connected in series between an oil inlet and the inlet of each electromagnetic on-off valve, through which oil enters the first control chamber and the second control chamber; The fault-tolerant method is based on the high-safety array landing gear retraction and steering valve, and comprises the following steps: Upon receiving an instruction for driving the steering of the main valve, defining the pilot control stage corresponding to the instruction as a target-side pilot control stage, and defining the other pilot control stage as a non-target-side pilot control stage; sending an opening instruction to at least two electromagnetic on-off valves of the valve group of the target-side pilot control stage, and sending a closing instruction to the electromagnetic on-off valves of the other target-side pilot control stage and the non-target-side pilot control stage, so as to depressurize the control chamber corresponding to the target-side pilot control stage, and form a pressure difference between the first control chamber and the second control chamber of the main valve for driving the steering of the main valve; judging the execution of the opening and closing instructions based on the pressure information obtained by the first pressure sensor or the second pressure sensor; when it is monitored that the pressure of the control chamber corresponding to the target-side pilot control stage does not change as per the preset logic, diagnosing that there is a fault in the electromagnetic on-off valve, and dynamically adjusting the opening state of the other electromagnetic on-off valves of the valve group of the target-side pilot control stage and / or the valve group of the non-target-side pilot control stage, so as to compensate for the pressure change caused by the fault, and ensure that the main valve can still steer or remain in the neutral position.

2. The fault-tolerant method of claim 1, wherein, The valve group is composed of three parallel electromagnetic on-off valves, and the first control chamber and the second control chamber of the main valve are balanced in pressure, and the main valve remains in the neutral position, and the landing gear is in a safe floating mode.

3. The fault-tolerant method of claim 1, wherein, The electromagnetic on-off valve is a two-position two-way electromagnetic on-off valve.

4. The fault-tolerant method of claim 1, wherein, The valve group is composed of three parallel electromagnetic on-off valves, and in the normal working mode, the step of sending an opening instruction to the valve group of the target-side pilot control stage comprises: adopting a "two out of three" control logic to open any two of the three electromagnetic on-off valves.

5. The fault-tolerant method of claim 4, wherein, The diagnosis of the fault in the electromagnetic on-off valve is specifically diagnosing that a certain electromagnetic on-off valve in the valve group of the target-side pilot control stage has a "power-on but not opening" fault; When it is necessary to drive the steering of the main valve, the specific steps of dynamic adjustment are: opening the other electromagnetic on-off valves in the valve group of the target-side pilot control stage except the fault electromagnetic on-off valve.

6. The fault-tolerant method of claim 4, wherein, Diagnose that there is an electromagnetic switch valve fault, specifically diagnose that a certain electromagnetic switch valve in the valve group of the non-target side pilot control stage occurs "power-off failure to close" fault; When it is necessary to drive the main valve to reverse, the specific steps of dynamic adjustment are: open all three electromagnetic switch valves in the valve group of the target side pilot control stage.

7. The fault-tolerant method of claim 4, wherein, Diagnose that there is an electromagnetic switch valve fault, specifically diagnose that a certain electromagnetic switch valve in the valve group of the target side pilot control stage and the valve group of the non-target side pilot control stage occurs "power-off failure to close" fault; When it is necessary to drive the main valve to reverse, the specific steps of dynamic adjustment are: open the electromagnetic switch valves in the valve group of the target side pilot control stage except the fault electromagnetic switch valve.

8. The fault-tolerant method of claim 4, wherein, Diagnose that there is an electromagnetic switch valve fault, specifically diagnose that a certain two electromagnetic switch valves in the valve group of the target side pilot control stage or the valve group of the non-target side pilot control stage both occur faults; When it is diagnosed that a certain two electromagnetic switch valves in the valve group of the target side pilot control stage both occur "power-on failure to open" fault, the specific steps of dynamic adjustment are: make all electromagnetic switch valves in the valve group of the target side pilot control stage and the valve group of the non-target side pilot control stage be in power-off state, and make the main valve remain in the middle position; When it is diagnosed that a certain two electromagnetic switch valves in the valve group of the non-target side pilot control stage both occur "power-off failure to close" fault, the specific steps of dynamic adjustment are: open any two electromagnetic switch valves in the valve group of the target side pilot control stage to power on, and make the main valve remain in the middle position.

9. The fault-tolerant method of claim 1, wherein, The step of judging the execution of the opening instruction based on the pressure information obtained by the first pressure sensor and the second pressure sensor is specifically: Compare the actual pressure change monitored by the first pressure sensor and the second pressure sensor with a preset pressure change threshold or a preset pressure change curve to judge whether the pressure of the control cavity corresponding to the target side pilot control stage changes according to the preset logic.

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