An aircraft electronically controlled hydraulic actuation system

Abstract

The present invention belongs to the field of aviation electromechanical technology, and in particular relates to an electronically controlled hydraulic actuation system for an aircraft. A control unit is connected to a motor for controlling the start and stop, rotation direction, and speed of the motor. The output shaft of the motor is connected to the drive shaft of a bidirectional quantitative gear pump, and the motor is used to drive the bidirectional quantitative gear pump to work and control the working direction. Port b of the bidirectional quantitative gear pump is connected to port 8b of an unloading solenoid valve, port 10b of a shuttle valve, and port 11a of a first hydraulic one-way valve through a first pipeline. Port 11c of the first hydraulic one-way valve is connected to port 12a of an actuator. Port a of the bidirectional quantitative gear pump is connected to port 8a of the unloading solenoid valve, port 10a of the shuttle valve, and port 14a of a second hydraulic one-way valve through a second pipeline. Port 14c of the second hydraulic one-way valve is connected to port 12b of the actuator. The common port 10c of the shuttle valve is connected to control port 11b of the first hydraulic one-way valve and control port 14b of the second hydraulic one-way valve. The piston rod of the actuator is used to drive the movement of a controlled device.

Description

Technical Field

[0001] The present invention belongs to the field of aviation electromechanical technology, and in particular relates to an aircraft electronically controlled hydraulic actuation system. Background Art

[0002] When an aircraft's actuation system is subject to heavy loads, a hydraulic system can be used as a power source to extend and retract the piston rod of a hydraulic cylinder to achieve high-load movement. For example, a typical hatch door opening and closing operation uses hydraulic energy to drive a linear actuator for reciprocating motion. Aircraft hydraulic actuation systems typically employ an open-loop hydraulic system, where a hydraulic pump draws oil from a tank and delivers pressurized oil to the system. The return oil from the actuator returns to the tank, where the working fluid cools and settles before recirculating. Actuator direction and speed control typically utilizes a throttling speed control system, consisting of a metering pump, a relief valve, a throttle valve, a reversing valve, and an actuator. The operating process is as follows: The pressurized oil generated by the metering pump is controlled by changing the operating position of the reversing valve. The flow enters the rod chamber or rodless chamber of the actuator, extending and retracting the piston rod. The throttle valve regulates the flow rate to the actuator to achieve speed control, and the relief valve regulates system pressure to protect the system.

[0003] The hydraulic opening and closing devices of aircraft cargo doors usually have the following functions:

[0004] (1) Automatic opening and closing function of the cargo door. The hydraulic system is activated through the cargo door control switch in the cockpit or ground station to open and close the door. After the action is completed, the hydraulic energy system is automatically cut off or unloaded.

[0005] (2) Cargo door status indication, which informs the flight crew, ground crew or pilot whether the cargo door is open, closed or in operation.

[0006] (3) Fault protection function: when the hydraulic energy is lost or the system is over-pressurized, the system will be unloaded to protect the pump source. Some cargo doors with smaller loads can be manually operated when the hydraulic power is lost.

[0007] For traditional hydraulic actuation systems that use reversing valves to control the movement direction of the actuator, internal leakage of the reversing valve often causes the system to be unable to change the oil flow direction as required, making it difficult to meet the system's functional and reliability requirements. In addition, the pipelines between the hydraulic pump and hydraulic valve in the traditional hydraulic actuation system also place a huge burden on the aircraft's weight indicators. Summary of the Invention

[0008] Purpose of the invention:

[0009] (1) Realize the electric control function of hydraulic actuators of aircraft or UAVs;

[0010] (2) Alleviate the problem of large starting current of electric pumps;

[0011] (3) Effectively solve the problems of large size, heavy weight and high power loss caused by the throttling speed control circuit used in the open hydraulic system of traditional civil aircraft;

[0012] (4) A distributed layout is adopted, that is, an independent electronically controlled hydraulic circuit that is not interconnected with other hydraulic subsystems on the aircraft. Therefore, the implementation form of the electrostatic hydraulic actuator (EHA) can be adopted. This is the current design trend of mainstream more-electric aircraft and can improve the reliability of the aircraft.

[0013] Technical solution:

[0014] An aircraft electronically controlled hydraulic actuation system includes: a control unit, an electric motor, a bidirectional quantitative gear pump, an unloading solenoid valve, a shuttle valve, a first hydraulic one-way valve, a second hydraulic one-way valve, an actuator, and an oil supply circuit;

[0015] The control unit is connected to the motor and is used to control the start and stop, rotation direction and speed of the motor;

[0016] The output shaft of the motor is connected to the drive shaft of the bidirectional quantitative gear pump, and the motor is used to drive the bidirectional quantitative gear pump to work and control the working direction;

[0017] The oil port b of the bidirectional quantitative gear pump is connected to the oil port 8b of the unloading solenoid valve, the oil port 10b of the shuttle valve and the oil port 11a of the first hydraulic one-way valve through pipeline 1; the oil port 11c of the first hydraulic one-way valve is connected to the rodless cavity oil port 12a of the actuator; the oil port a of the bidirectional quantitative gear pump is connected to the oil port 8a of the unloading solenoid valve, the oil port 10a of the shuttle valve and the oil port 14a of the second hydraulic one-way valve through pipeline 2, and the oil port 14c of the second hydraulic one-way valve is connected to the rod cavity oil port 12b of the actuator;

[0018] The common port 10c of the shuttle valve is communicated with the control port 11b of the first hydraulic one-way valve and the control port 14b of the second hydraulic one-way valve respectively;

[0019] The piston rod of the actuator is used to drive the controlled device to move;

[0020] The oil replenishment circuit includes: a first one-way valve, a second one-way valve, a third one-way valve and an accumulator; the housing oil port C of the bidirectional quantitative gear pump collects oil leaking from the gear pump and is connected through the input end of the first one-way valve, and the output end of the first one-way valve is connected to the accumulator; the accumulator is also connected to the input ends of the second one-way valve and the third one-way valve, and the output ends of the second one-way valve and the third one-way valve are connected to pipeline one and pipeline two respectively; the oil replenishment circuit is used to collect internal leakage from the bidirectional quantitative gear pump and replenish oil for the low-pressure oil circuit of the system.

[0021] Further, the system further comprises: a first position sensor and a second position sensor;

[0022] The first position sensor and the second position sensor are arranged at both ends of the moving track of the controlled device; the first position sensor and the second position sensor are both connected to the control unit for detecting whether the controlled device has moved to the extreme position; when it moves to the extreme position, a position signal is sent to the control unit, and after receiving the position signal, the control unit controls the motor to stop running.

[0023] Furthermore, the system further comprises: a first pressure regulating valve and a second pressure regulating valve; the input end of the first pressure regulating valve is connected to pipeline 1, and the output end is connected to pipeline 2; the input end of the second pressure regulating valve is connected to pipeline 1, and the output end is connected to pipeline 2;

[0024] The first / second pressure regulating valve is used to open when the oil pressure in pipeline one / pipeline two exceeds the set pressure, and return the over-pressure oil to pipeline two / one to maintain the oil pressure in pipeline one / pipeline two not exceeding the set pressure.

[0025] Furthermore, the effective working pressure of the pressure accumulator is lower than the set pressure of the first / second pressure regulating valve.

[0026] Furthermore, the system further comprises: two oil filters, which are respectively arranged at the oil port a and the oil port b of the bidirectional quantitative gear pump.

[0027] Furthermore, the system further includes: a first pressure sensor and a second pressure sensor, wherein the first pressure sensor and the second pressure sensor are respectively arranged in pipeline one and pipeline two, and are used to monitor the oil pressure in pipeline one and pipeline two.

[0028] Further, the controlled device is a hatch;

[0029] When the control unit receives the signal to open the hatch, the control unit controls the unloading solenoid valve to be energized and connected. At this time, the oil port a of the two-way quantitative gear pump is connected as the oil suction port and the oil port b as the oil discharge port and unloads. The control unit also controls the motor to start and drive the two-way quantitative gear pump to rotate forward. After a delay of 1s, the unloading solenoid valve is de-energized and closed. The pressure oil generated by the two-way quantitative gear pump passes through the oil port b and enters the rodless cavity oil port 12a of the actuator through the first hydraulic one-way valve, pushing the piston rod of the actuator to extend, thereby realizing the function of opening the hatch. At the same time, the pressure oil enters the shuttle valve. At this time, due to the high pressure at the shuttle valve oil port 10b, the shuttle The valve oil port 10b is connected to the shuttle valve oil port 10c. The pressure oil flows from the shuttle valve oil port 10c into the control port 11b of the hydraulic check valve and the control port 14b of the second hydraulic check valve. At this time, the first and second hydraulic check valves are open, and the second hydraulic check valve oil port 14c is connected to the oil port 14a, so that the return oil of the actuator flows from the rod chamber oil port 12b through the oil port 14c and oil port 14a of the second hydraulic check valve and enters the oil port a of the two-way fixed displacement hydraulic pump. When the hatch is fully opened, the first position sensor is triggered. After receiving the signal from the first position sensor, the control unit stops driving the motor, and the hatch opening action is completed.

[0030] When the control unit receives the signal to close the hatch, the control unit controls the unloading solenoid valve to be energized and connected. At this time, the oil port b of the two-way quantitative gear pump is connected as the oil suction port and the oil port a is connected as the oil discharge port and unloaded. The control unit also controls the motor to start and drive the two-way quantitative gear pump; after a delay of 1s, the unloading solenoid valve is de-energized and closed, and the pressure oil generated by the two-way quantitative pump gear pump passes from the oil port a through the second hydraulic one-way valve into the rod chamber oil port 12b of the actuator, pushing the piston rod of the actuator to retract, thereby realizing the function of closing the hatch; at the same time, the pressure oil enters the shuttle valve. At this time, due to the high pressure at the oil port 10a of the shuttle valve, the oil of the shuttle valve is Port 10a is connected with the oil port 10c of the shuttle valve, and the pressure oil flows from the oil port 10c of the shuttle valve into the control port 11b of the first hydraulic check valve and the control port 14b of the second hydraulic check valve. At this time, the first and second hydraulic check valves are opened, and the oil port 11c of the first hydraulic check valve is connected with the oil port 11a, so that the return oil of the actuator passes from the rodless chamber oil port 12a through the oil port 11c and oil port 11a of the first hydraulic check valve into the oil port b of the bidirectional quantitative hydraulic pump; when the hatch is fully closed, the second position sensor is triggered, and the control unit stops driving the motor after receiving the signal from the second position sensor, and the hatch closing action is completed.

[0031] Furthermore, when the hatch stops sending opening and closing signals to the control unit during movement, the control unit controls the unloading solenoid valve to be energized. At this time, the pressures of the oil ports 10a and 10b of the shuttle valve are equal, and no pressurized oil flows into the control ports of the first and second hydraulic one-way valves. The first and second hydraulic one-way valves are not opened, and the oil in the rod chamber and the rodless chamber of the actuator cannot form a passage, thereby locking the piston rod position of the actuator and realizing the posture holding function.

[0032] Furthermore, when the first and second position sensors do not receive the in-position signal within the specified time, the control unit controls the motor to stop working and controls the unloading solenoid valve to energize. At this time, the oil port a and the oil port b of the bidirectional quantitative gear pump are connected to avoid damage to the motor due to excessive pressure or long-term load operation;

[0033] The prescribed time is greater than the theoretical motion duration of the controlled device.

[0034] The advantages of the present invention are:

[0035] (1) A closed hydraulic system is used, where the actuator oil return port is directly connected to the hydraulic pump oil suction port. This avoids the need for an open system to have a large oil tank for storing oil and dissipating heat, saving space and weight. In addition, during a flight mission, the cargo door drive system does not work all the time, and each working time does not exceed 1 minute, which can effectively avoid the problem of high heat generation in the closed system.

[0036] (2) Using a bidirectional hydraulic pump and eliminating the reversing valve can effectively reduce the weight of the system;

[0037] (3) The use of a bidirectional quantitative gear pump has a better power-to-weight ratio than an axial piston pump, and can avoid the current problem of blindly replacing the throttling speed control circuit with a volume control circuit based on an axial constant pressure variable piston pump to improve system efficiency and reduce system heat generation, which causes system weight increase;

[0038] (4) It has a posture holding function, that is, the actuator can stop at any position within the motion envelope;

[0039] (5) It has an unloading function, which balances the load of the hydraulic pump inlet and outlet when the bidirectional hydraulic pump is started, and connects the pump's oil outlet and oil intake in the event of a system failure to protect the motor and hydraulic pump. When the hydraulic pump is started, the hydraulic pump's oil intake and oil discharge ports are connected, and the hydraulic pump starts without load, which can effectively reduce the problem of excessive starting current of the hydraulic pump, which easily exceeds the aircraft's electrical load capacity.

[0040] (6) It is completely isolated from the aircraft's main hydraulic system or other hydraulic systems with a higher level of hazard, and is allowed to take off after the cargo door is closed in a faulty state, without affecting the safety and economy of the civil aircraft.

[0041] (7) The entire system is implemented using an electrostatic hydraulic actuator, which is the current design trend of the mainstream multi-point aircraft hydraulic actuation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the principle of an aircraft electronically controlled hydraulic actuation system. DETAILED DESCRIPTION

[0043] An aircraft electronically controlled hydraulic actuation system, such as Figure 1 As shown, it consists of a control unit, an electric motor 1, a bidirectional quantitative gear pump 2, a casing oil return one-way valve 3, an accumulator 4, an oil filter 5, a pressure sensor 6, a one-way valve 7, an unloading solenoid valve 8, a pressure regulating valve 9, a shuttle valve 10, a hydraulic one-way valve 11, an actuator 12, a position sensor 13, a hydraulic one-way valve 14, a position sensor 15, an oil filter 16, and a pressure sensor 17. The output shaft of motor 1 is mechanically connected to the drive shaft of bidirectional fixed-displacement gear pump 2. Oil port b of gear pump 2 is connected to oil filter 5, sensor 6, port 8b of unloading solenoid valve 8, pressure regulating valve 9, port 10b of shuttle valve 10, hydraulic check valve 11, and port 12a of actuator 12. Oil port a of gear pump 2 is connected to oil filter 16, sensor 17, port 8a of unloading solenoid valve 8, pressure regulating valve 9, port 10a of shuttle valve 10, hydraulic check valve 14, and port 12b of actuator 12. Case oil return port c of gear pump 2 is connected to case oil return check valve 3, accumulator 4, and check valve 7. Oil in accumulator 4 flows only to the oil intake port of gear pump 2. The control unit receives control signals to control the operation of motor 1 and unloading solenoid valve 8. It also receives pressure signals from pressure sensors 6 and 17, as well as position signals from position sensors 13 and 15. The piston rod of the actuator is used to drive the controlled device.

[0044] The controlled device can be a hatch, a rudder, etc. The following describes the working principle using a hatch as the controlled device:

[0045] When the control unit receives the signal to open the hatch, the control unit controls the unloading solenoid valve 8 to be energized and turned on. At this time, the oil suction port a of the bidirectional quantitative gear pump 2 is connected to the oil discharge port b and unloaded. The control unit also controls the motor 1 to start and drive the bidirectional quantitative gear pump 2.

[0046] After a delay of 1s, the unloading solenoid valve 8 is de-energized and closed, and the pressure oil generated by the bidirectional quantitative pump gear pump 2 passes through the oil filter 5 and the hydraulic one-way valve 11 from the b port into the 12a port of the actuator 12, pushing the piston rod of the actuator 12 to extend, thereby realizing the function of opening the hatch.

[0047] At the same time, the pressure oil enters the shuttle valve 10. At this time, due to the high pressure at port 10b, 10b is connected to 10c, and the pressure oil flows from 10c into the control port 11b of the hydraulic check valve 11 and the control port 14b of the hydraulic check valve 14. At this time, the hydraulic check valves 11 and 14 are open, and 14c is connected to 14a, so that the return oil of the actuator 12 passes from 12b through 14c, 14a and the oil filter 16 and enters the oil suction port a of the bidirectional quantitative hydraulic pump 2.

[0048] When the door is fully opened, the position sensor 15 is triggered, and the control unit stops driving the motor 1 after receiving the signal from the position sensor 15, and the door opening action is completed.

[0049] When the control unit receives the signal to close the hatch, the control unit controls the unloading solenoid valve 8 to be energized and turned on. At this time, the oil suction port b of the bidirectional quantitative gear pump 2 is connected to the oil discharge port a and unloaded. The control unit also controls the motor 1 to start and drive the bidirectional quantitative gear pump 2.

[0050] After a delay of 1s, the unloading solenoid valve 8 is de-energized and closed, and the pressure oil generated by the bidirectional quantitative pump gear pump 2 passes through the oil filter 16 and the hydraulic one-way valve 14 from the a port into the 12b port of the actuator 12, pushing the piston rod of the actuator 12 to retract, thereby realizing the function of opening the hatch.

[0051] At the same time, the pressure oil enters the shuttle valve 10. At this time, due to the high pressure at port 10a, 10a and 10c are connected, and the pressure oil flows from 10c into the control port 11b of the hydraulic check valve 11 and the control port 14b of the hydraulic check valve 14. At this time, the hydraulic check valves 14 and 11 are open, 11c is connected to 11a, and the return oil of the actuator 12 passes from 12a through 11c, 11a and the oil filter 5 and enters the oil suction port b of the bidirectional quantitative hydraulic pump 2.

[0052] When the door is fully opened, the position sensor 13 is triggered, and the control unit stops driving the motor 1 after receiving the signal from the position sensor 13, and the door closing action is completed.

[0053] During the process of opening and closing the hatch, the pressure sensor 6 and the pressure sensor 17 respectively indicate the pressure of the pressure circuit, prompting that the system is in working state, and adjust the pressure of the pressure circuit through the two pressure regulating valves 9 so that the pressure does not exceed the design value.

[0054] Due to the use of a bidirectional quantitative gear pump 2, its internal leakage enters the oil replenishment circuit of the accumulator 4 through the shell oil return one-way valve 3; during the operation of the system, the effective working pressure of the accumulator 4 is set to be lower than the set pressure of the pressure regulating valve 9. The accumulator 4 is mainly used to replenish oil in the oil circuit and provide a certain oil suction pressure for the oil suction port of the bidirectional quantitative gear pump 2 to prevent cavitation in the pump, and controls the flow direction of the pressure oil in the oil replenishment circuit through two one-way valves 7, so that it only flows into the oil suction port of the pump.

[0055] When the hatch moves and the opening and closing signals to the control unit are stopped, the control unit controls the unloading solenoid valve 8 to be energized. At this time, the pressures at ports 10a and 10b of the shuttle valve 10 are equal, so no pressurized oil flows into the control ports of the hydraulic one-way valves 11 and 14. Both one-way valves are not opened, and the oil in the rod chamber and the rodless chamber of the actuator 12 cannot form a passage, thereby locking the piston rod position of the actuator 12 and realizing the posture holding function.

[0056] If a system failure occurs—that is, the control unit does not receive a door-in-place signal from position sensors 13 and 15 within the set time, while pressure sensors 6 or 17 in the pressure circuit receive a pressure signal—the control unit stops motor 1 and energizes unloading solenoid valve 8. This connects the oil intake and discharge ports of the two-way quantitative gear pump, effectively preventing damage to the hydraulic pump and motor due to excessive pressure or prolonged load operation. The set time is the theoretical time it takes for the door to open or close, plus a waiting delay of a certain length, such as two seconds.

Claims

1. An aircraft electronically controlled hydraulic actuation system, characterized by: The system includes: a control unit, an electric motor, a bidirectional quantitative gear pump, an unloading solenoid valve, a shuttle valve, a first hydraulic one-way valve, a second hydraulic one-way valve, an actuator, and an oil supply circuit; The control unit is connected to the motor and is used to control the start and stop, rotation direction and speed of the motor; The output shaft of the motor is connected to the drive shaft of the bidirectional quantitative gear pump, and the motor is used to drive the bidirectional quantitative gear pump to work and control the working direction; The oil port b of the bidirectional quantitative gear pump is connected to the oil port 8b of the unloading solenoid valve, the oil port 10b of the shuttle valve and the oil port 11a of the first hydraulic one-way valve through pipeline 1; the oil port 11c of the first hydraulic one-way valve is connected to the rodless cavity oil port 12a of the actuator; the oil port a of the bidirectional quantitative gear pump is connected to the oil port 8a of the unloading solenoid valve, the oil port 10a of the shuttle valve and the oil port 14a of the second hydraulic one-way valve through pipeline 2, and the oil port 14c of the second hydraulic one-way valve is connected to the rod cavity oil port 12b of the actuator; The common port 10c of the shuttle valve is communicated with the control port 11b of the first hydraulic one-way valve and the control port 14b of the second hydraulic one-way valve respectively; The piston rod of the actuator is used to drive the controlled device to move; The oil replenishment circuit includes: a first one-way valve, a second one-way valve, a third one-way valve and an accumulator; the housing oil port C of the bidirectional quantitative gear pump collects oil leaking from the gear pump and is connected through the input end of the first one-way valve, and the output end of the first one-way valve is connected to the accumulator; the accumulator is also connected to the input ends of the second one-way valve and the third one-way valve, and the output ends of the second one-way valve and the third one-way valve are connected to pipeline one and pipeline two respectively; the oil replenishment circuit is used to collect internal leakage from the bidirectional quantitative gear pump and replenish oil for the low-pressure oil circuit of the system.

2. The system according to claim 1, characterized in that: The system further includes: a first position sensor and a second position sensor; The first position sensor and the second position sensor are arranged at both ends of the moving track of the controlled device; the first position sensor and the second position sensor are both connected to the control unit for detecting whether the controlled device has moved to the extreme position; when it moves to the extreme position, a position signal is sent to the control unit, and after receiving the position signal, the control unit controls the motor to stop running.

3. The system according to claim 2, characterized in that: The system further includes: a first pressure regulating valve and a second pressure regulating valve; the input end of the first pressure regulating valve is connected to pipeline 1, and the output end is connected to pipeline 2; the input end of the second pressure regulating valve is connected to pipeline 1, and the output end is connected to pipeline 2; The first / second pressure regulating valve is used to open when the oil pressure in pipeline one / pipeline two exceeds the set pressure, and return the over-pressure oil to pipeline two / one to maintain the oil pressure in pipeline one / pipeline two not exceeding the set pressure.

4. The system according to claim 3, characterized in that: The effective working pressure of the pressure accumulator is lower than the set pressure of the first / second pressure regulating valve.

5. The system according to claim 4, characterized in that: The system further comprises: two oil filters, which are respectively arranged at the oil port a and the oil port b of the bidirectional quantitative gear pump.

6. The system according to claim 5, characterized in that: The system further includes a first pressure sensor and a second pressure sensor, wherein the first pressure sensor and the second pressure sensor are respectively disposed in the first pipeline and the second pipeline and are used to monitor the oil pressure in the first pipeline and the second pipeline.

7. The system according to claim 6, characterized in that: The controlled device is a hatch; When the control unit receives the signal to open the hatch, the control unit controls the unloading solenoid valve to be energized and connected. At this time, the oil port a of the two-way quantitative gear pump is connected as the oil suction port and the oil port b as the oil discharge port and unloads. The control unit also controls the motor to start and drive the two-way quantitative gear pump to rotate forward. After a delay of 1s, the unloading solenoid valve is de-energized and closed. The pressure oil generated by the two-way quantitative gear pump passes through the oil port b and enters the rodless cavity oil port 12a of the actuator through the first hydraulic one-way valve, pushing the piston rod of the actuator to extend, thereby realizing the function of opening the hatch. At the same time, the pressure oil enters the shuttle valve. At this time, due to the high pressure at the shuttle valve oil port 10b, the shuttle The valve oil port 10b is connected to the shuttle valve oil port 10c. The pressure oil flows from the shuttle valve oil port 10c into the control port 11b of the hydraulic check valve and the control port 14b of the second hydraulic check valve. At this time, the first and second hydraulic check valves are open, and the second hydraulic check valve oil port 14c is connected to the oil port 14a, so that the return oil of the actuator flows from the rod chamber oil port 12b through the oil port 14c and oil port 14a of the second hydraulic check valve and enters the oil port a of the two-way fixed displacement hydraulic pump. When the hatch is fully opened, the first position sensor is triggered. After receiving the signal from the first position sensor, the control unit stops driving the motor, and the hatch opening action is completed. When the control unit receives the signal to close the hatch, the control unit controls the unloading solenoid valve to be energized and connected. At this time, the oil port b of the two-way quantitative gear pump is connected as the oil suction port and the oil port a is connected as the oil discharge port and unloaded. The control unit also controls the motor to start and drive the two-way quantitative gear pump; after a delay of 1s, the unloading solenoid valve is de-energized and closed, and the pressure oil generated by the two-way quantitative pump gear pump passes from the oil port a through the second hydraulic one-way valve into the rod chamber oil port 12b of the actuator, pushing the piston rod of the actuator to retract, thereby realizing the function of closing the hatch; at the same time, the pressure oil enters the shuttle valve. At this time, due to the high pressure at the oil port 10a of the shuttle valve, the oil of the shuttle valve is Port 10a is connected with the oil port 10c of the shuttle valve, and the pressure oil flows from the oil port 10c of the shuttle valve into the control port 11b of the first hydraulic check valve and the control port 14b of the second hydraulic check valve. At this time, the first and second hydraulic check valves are opened, and the oil port 11c of the first hydraulic check valve is connected with the oil port 11a, so that the return oil of the actuator passes from the rodless chamber oil port 12a through the oil port 11c and oil port 11a of the first hydraulic check valve into the oil port b of the bidirectional quantitative hydraulic pump; when the hatch is fully closed, the second position sensor is triggered, and the control unit stops driving the motor after receiving the signal from the second position sensor, and the hatch closing action is completed.

8. The system according to claim 7, characterized in that: When the hatch moves and stops sending opening and closing signals to the control unit, the control unit controls the unloading solenoid valve to be energized. At this time, the pressures of the oil ports 10a and 10b of the shuttle valve are equal, and no pressurized oil flows into the control ports of the first and second hydraulic one-way valves. The first and second hydraulic one-way valves are not opened, and the oil in the rod chamber and the rodless chamber of the actuator cannot form a passage, thereby locking the piston rod position of the actuator and realizing the posture holding function.

9. The system according to claim 8, characterized in that: When the first and second position sensors do not receive the in-position signal within the specified time, the control unit controls the motor to stop working and controls the unloading solenoid valve to energize. At this time, the oil port a and the oil port b of the bidirectional quantitative gear pump are connected to avoid damage to the motor due to excessive pressure or long-term load operation; The prescribed time is greater than the theoretical motion duration of the controlled device.

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