Hydraulic control system for an aircraft landing gear

Abstract

The utility model discloses an aircraft landing gear hydraulic control system, including a plurality of hydraulic control module, hydraulic power module and system control module, each hydraulic control module is provided with the action cylinder, and the rod cavity and the rod cavity of action cylinder are connected flow control valve group through hydraulic connection pipeline, and hydraulic power module includes hydraulic circuit, oil pump, motor and oil tank, and the flow control valve group of each hydraulic control module is connected on the hydraulic circuit, and system control module includes controller and a plurality of sensors, and a plurality of sensors, hydraulic control module and hydraulic power module are connected controller respectively, and controller gives hydraulic control module and hydraulic power module output control instruction according to the feedback of a plurality of sensors, the utility model discloses the landing gear on aircraft is equipped with hydraulic control system, and through hydraulic power module control action cylinder telescopic, adjusts aircraft fuselage, guarantees the balance of aircraft fuselage, improves the stability of aircraft take -off and landing.

Description

Technical Field

[0001] This utility model relates to the field of aircraft landing gear control technology, and in particular to an aircraft landing gear hydraulic control system. Background Technology

[0002] Vertical takeoff and landing (VTOL) aircraft are typically used to perform missions in complex terrain environments. Most existing VTOL aircraft have landing gear that is rigidly connected to the fuselage or connected via damping buffers. These types of landing gear have high requirements for the takeoff and landing sites and environment, requiring flat ground and no crosswinds for takeoff and landing operations. In unstructured takeoff and landing sites such as ramps and mountains, or in environments with complex weather conditions (such as strong crosswinds), the landing gear cannot adjust the support force on the stressed side to change the fuselage attitude, making it prone to tipping over. Utility Model Content

[0003] In response to the shortcomings of existing aircraft landing gear, the applicant provides a reasonably structured aircraft landing gear hydraulic control system, which includes a hydraulically controlled retractable actuator on the landing gear that can be adjusted according to actual conditions to improve the stability of aircraft takeoff and landing.

[0004] The technical solution adopted in this utility model is as follows: A hydraulic control system for aircraft landing gear, mounted on the aircraft fuselage, includes several hydraulic control modules, a hydraulic power module, and a system control module. Each hydraulic control module has an actuator, with its rod-side and rodless-side chambers interconnected. The rod-side and rodless-side chambers are connected to a flow control valve assembly via hydraulic connecting pipes. The hydraulic power module includes a hydraulic circuit, an oil pump, a motor, and an oil tank. The oil pump and oil tank are connected to the hydraulic circuit, with the oil pump's inlet connected to the oil tank, and the motor connected to the oil pump. The flow control valve assembly of each hydraulic control module is connected to the hydraulic circuit. The system control module includes a controller and several sensors. The sensors, hydraulic control modules, and hydraulic power modules are respectively connected to the controller. The controller outputs control commands to the hydraulic control modules and hydraulic power modules based on feedback from the sensors.

[0005] As a further improvement to the above technical solution: Each hydraulic control module is equipped with a stiffness accumulator, which is connected to the hydraulic connection pipeline. A one-way throttle valve assembly is installed between the stiffness accumulator and the hydraulic connection pipeline.

[0006] The rod chamber and rodless chamber of the actuator are connected to each other through a valve plate on the piston. The actuator has a single oil port, which connects the rod chamber and the rodless chamber. The hydraulic connection pipeline is connected to the oil port.

[0007] The flow control valve assembly is equipped with a hydraulic compensation valve, a solenoid directional valve, and a check valve with pressure lock.

[0008] The hydraulic circuit of the hydraulic power module is connected in series with a check valve and a solenoid valve. The check valve is located between the oil inlet of the flow control valve group and the oil pump outlet, and the solenoid valve is located between the oil return port of the flow control valve group and the oil tank.

[0009] An overflow circuit is connected in parallel on the hydraulic circuit. One end of the overflow circuit is connected between the check valve and the oil pump, and the other end is connected between the solenoid valve and the oil tank. An overflow valve is installed on the overflow circuit.

[0010] The system control module's sensors include a displacement sensor and a pressure sensor. The displacement sensor is mounted on the actuator rod of the actuator cylinder, and the pressure sensor is mounted on the hydraulic connection pipeline, located between the one-way throttle valve assembly and the flow control valve assembly.

[0011] The system control module's sensors include a terrain sensor and an airframe attitude sensor. The terrain sensor is located on the lower part of the aircraft's fuselage, while the airframe attitude sensor is located on the aircraft's fuselage or integrated into the controller.

[0012] The hydraulic control module is a hydraulic control loop with active and passive differential control, and at least three hydraulic control modules are set up.

[0013] The beneficial effects of this utility model are as follows: This invention equips the landing gear of an aircraft with a hydraulic control system. According to the actual situation, the hydraulic power module controls the extension and retraction of the actuator cylinder to adjust the aircraft fuselage, ensure the balance of the aircraft fuselage, and improve the stability of the aircraft take-off and landing. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the control system of this utility model.

[0015] In the diagram: 1. Actuator; 2. Oil port; 3. Stiffness accumulator; 4. One-way throttle valve assembly; 5. Displacement sensor; 6. Hydraulic connection pipeline; 7. Flow control valve assembly; 71. Hydraulic compensation valve; 72. Solenoid directional valve; 73. One-way valve; 8. Pressure sensor; 9. Hydraulic circuit; 10. Oil pump; 11. Motor; 12. Oil tank; 13. One-way valve; 14. Solenoid valve; 15. Overflow circuit; 16. Overflow valve; 17. Terrain sensor; 18. Aircraft attitude sensor; 19. Controller. Detailed Implementation

[0016] The specific embodiments of this utility model are described below with reference to the accompanying drawings.

[0017] like Figure 1 As shown, the aircraft landing gear hydraulic control system of this utility model includes a hydraulic control module, a hydraulic power module, and a system control module.

[0018] The hydraulic control module is a hydraulic control circuit with active and passive differential control. There are N hydraulic control modules, where N≥3. Each hydraulic control module has an actuator cylinder 1 and a stiffness accumulator 3. An actuator cylinder 1 contains a piston with an actuating rod connected to it. The piston divides the cylinder's interior into a rod chamber and a rodless chamber, with the actuating rod located in the rod chamber. The rodless chamber of actuator cylinder 1 faces downwards towards the ground and connects to the wheels or landing gear, while the rod chamber faces upwards, with the actuating rod connecting to the fuselage. The rod chamber and rodless chamber of actuator cylinder 1 are interconnected via a valve on the piston. A single oil port 2 is provided on actuator cylinder 1, connecting the rod chamber and rodless chamber. Actuator cylinder 1 uses a single-port design to reduce piping. The valve design on the piston allows for controllable oil inflow and outflow speeds, precisely controlling the lifting and lowering speeds of actuator cylinder 1 and preventing the risk of overspeeding and loss of control. The oil port 2 of the actuator cylinder 1 is connected to the flow control valve assembly 7 via the hydraulic connection pipeline 6. The flow control valve assembly 7 is connected to the hydraulic power module. The flow control valve assembly 7 controls the hydraulic oil entering and exiting the hydraulic control module, controlling the flow rate of the oil circuit according to demand, thereby controlling the flow rate of the hydraulic oil entering and exiting. The stiffness accumulator 3 is connected to the hydraulic connection pipeline 6. A one-way throttle valve assembly 4 is installed between the stiffness accumulator 3 and the hydraulic connection pipeline 6. The one-way throttle valve assembly 4 controls the oil flowing into and out of the stiffness accumulator 3. During dynamic system adjustment, the stiffness accumulator 3 can absorb system pressure fluctuations and prevent hydraulic components from bearing periodic alternating loads. The stiffness accumulator 3 also acts as a buffer during aircraft landing, reducing the impact on the aircraft. The flow control valve assembly 7 is equipped with a hydraulic compensation valve 71, a solenoid directional valve 72, and a one-way valve 73 with pressure lock. The hydraulic compensation valve 71 can maintain a constant hydraulic pressure difference between the inlet and outlet flow control valve group 7, avoiding the problem of unstable pressure before and after the system flow control; the solenoid directional valve 72 controls the oil flow by controlling the valve opening; the check valve 73 with pressure lock can prevent the oil entering the actuator 1 from flowing back, and the check valve 73 is opened by pressure lock when the oil needs to flow back to the oil tank 12.

[0019] The hydraulic power module includes a hydraulic circuit 9, an oil pump 10, a motor 11, and an oil tank 12. The hydraulic circuit 9 is a one-way circuit. The oil pump 10 and the oil tank 12 are connected to the hydraulic circuit 9. The oil inlet of the oil pump 10 is connected to the oil tank 12. The motor 11 is connected to the oil pump 10 and drives the oil pump 10 to operate. The flow control valve group 7 of each hydraulic control module is connected to the hydraulic circuit 9. A second check valve 13 and a solenoid valve 14 are connected in series on the hydraulic circuit 9. The second check valve 13 is located between the oil inlet of the flow control valve group 7 and the oil pump 10 outlet. The solenoid valve 14 is located between the return port of the flow control valve group 7 and the oil tank 12. An overflow circuit 15 is connected in parallel on the hydraulic circuit 9. One end of the overflow circuit 15 is connected between the second check valve 13 and the oil pump 10, and the other end is connected between the solenoid valve 14 and the oil tank 12. An overflow valve 16 is installed on the overflow circuit 15. The hydraulic power module uses a unidirectional circulation pipeline, which reduces the complexity of the system and facilitates the layout of the aircraft.

[0020] When the actuator cylinder 1 needs to extend, the motor 11 drives the oil pump 10 to work. The oil flows through the oil tank 12 and enters the hydraulic compensation valve 71 of the flow control valve group 7 through the second check valve 13. At this time, the solenoid directional valve 72 is in the neutral position, and the oil enters the actuator cylinder 1 through the first check valve 73. When the actuator cylinder 1 needs to shorten, the motor 11 drives the oil pump 10 to work. The oil flows through the oil tank 12 and enters the hydraulic compensation valve 71 of the flow control valve group 7 through the second check valve 13. At this time, the solenoid directional valve 72 is in the right position, and the oil enters the first check valve 73 with pressure lock through the control circuit. When the pressure lock is opened, the oil in the actuator cylinder 1 enters the oil tank 12 through the solenoid directional valve 72 and the solenoid valve 14.

[0021] The system control module includes a controller 19 and displacement sensors 5, pressure sensors 8, terrain sensors 17, and fuselage attitude sensors 18. Each sensor is connected to the controller 19, and the hydraulic control module and hydraulic power module are also connected to the controller 19. Displacement sensor 5 is mounted on the actuator rod of actuator cylinder 1 to sense the extension length of hydraulic differential actuator cylinder 1. Pressure sensor 8 is mounted on the hydraulic connection line 6, located between the one-way throttle valve group 4 and the flow control valve group 7, to sense the hydraulic pressure of the hydraulic control module. Terrain sensors 17 are located on the lower part of the aircraft fuselage to collect terrain data, such as the height difference of protrusions and the angle between the ground and the fuselage. Fuselage attitude sensors 18 are located on the fuselage of the aircraft or integrated into the controller 19 to collect real-time fuselage attitude and altitude data during flight. Each sensor transmits the collected data to the controller 19. The controller 19 calculates based on the collected data and the dynamic model of actuator cylinder 1, and outputs commands for the aircraft's descent speed and the flow rate of the flow control valve group. The system control module dynamically monitors and adjusts the system based on feedback from various sensors, thereby achieving closed-loop control and error correction.

[0022] In practical use, this utility model can realize multiple control modes, and the specific control process of different modes is as follows: (1) Compression of actuator cylinder 1: The actuator cylinder 1 begins to compress under the gravity of the aircraft fuselage. The hydraulic oil flows out from the rodless chamber of the actuator cylinder 1. Part of the hydraulic oil flows into the rod chamber of the actuator cylinder 1 and the stiffness accumulator 3. The other part of the hydraulic oil flows into the hydraulic circuit 9 through the flow control valve group 7 and into the oil tank 12 through the solenoid valve 14.

[0023] (2) Extension of actuator cylinder 1: The oil pump 10 sends oil through the one-way valve 13 into the hydraulic circuit 9, through the flow control valve group 7 and the hydraulic connection pipeline 6, part of which enters the stiffness accumulator 3 and part of which enters the rodless chamber of actuator cylinder 1, thus extending actuator cylinder 1.

[0024] (3) Surface landing buffer: Before the aircraft lands, the terrain sensor 17 scans the ground below the fuselage to determine the landing feasibility; at this time, the actuator 1 is in its longest position, the flow control valve group 7 is in the fully open state, and the solenoid valve 14 is in the open state; when an actuator 1 touches the ground, the actuator 1 begins to be compressed by the gravity of the aircraft. At this time, the other actuators 1 are not yet compressed until all actuators 1 are completely in contact with the ground and the center of gravity of the fuselage is adjusted to stabilize. The actuators 1 begin to be compressed by the gravity of the aircraft. The compression speed and compression amount of each actuator 1 are adjusted by the flow control valve group 7 to achieve descent buffer; when the fuselage attitude sensor 18 senses that the fuselage is balanced and the displacement sensor 5 reaches the preset state, each flow control valve group 7 closes, cuts off the oil flow, the actuators 1 stop compressing, and the fuselage altitude is maintained.

[0025] (4) Landing and leveling on uneven ground: When the aircraft lands on uneven ground, before landing, the terrain sensor 17 scans the ground below the fuselage to determine the landing feasibility; if the ground is not suitable for landing, an alarm is immediately triggered; when the ground meets the landing site requirements, each actuator 1 will contact the ground next to it in turn, and the fuselage will be leveled after all actuators 1 have contacted the ground to achieve the landing of the aircraft on uneven ground; the landing control action reference mode (3).

[0026] (5) Turbulence response before takeoff: When the aircraft is about to take off, it is affected by turbulence. The pressure sensor 8 in the hydraulic system on the pressure side can quickly sense the pressure change from the fuselage, i.e. the tilting trend. The controller 19 makes a judgment based on the pressure change. If necessary, it controls the actuator 1 in the corresponding direction to extend and adjust the angle from the opposite direction to counteract the potential tilt and maintain the balance of the fuselage.

[0027] (6) Soft ground response: When the aircraft wheels / landing gear contact the ground and there is insufficient ground support or sinking of the shape, the controller 19 judges the sinking of one side of the fuselage by the data of the fuselage attitude sensor 18 and pressure sensor 8, and controls the actuator 1 in the corresponding direction to extend in order to maintain the balance of the fuselage.

[0028] (7) Post-takeoff response: After the aircraft leaves the ground, actuator 1 is raised to its maximum length and flow control valve group 7 is closed.

[0029] (8) Failure Mode Landing: When the system malfunctions in the air, the electrical control components in the system fail, the flow control valve group 7 is in the closed state, and the oil in the actuator cylinder 1 cannot enter the hydraulic circuit 9 through the hydraulic connection pipeline 6. At this time, the actuator cylinder 1 is in its longest state. After grounding, the oil in the rodless chamber of the actuator cylinder 1 enters the stiffness accumulator 3 through the hydraulic connection pipeline 6 and the one-way throttle valve group 4, with the stiffness accumulator 3 serving as a buffer.

[0030] The above description is an explanation of the present utility model and not a limitation thereof. The present utility model can be modified in any form without departing from its spirit.

Claims

1. A hydraulic control system for aircraft landing gear, mounted on the fuselage of the aircraft, characterized in that: It includes several hydraulic control modules, hydraulic power modules, and system control modules; Each hydraulic control module is equipped with an actuator (1), the rod chamber and the rodless chamber of the actuator (1) are interconnected, and the rod chamber and the rodless chamber are connected to the flow control valve group (7) through the hydraulic connection pipeline (6). The hydraulic power module includes a hydraulic circuit (9), an oil pump (10), a motor (11), and an oil tank (12). The oil pump (10) and the oil tank (12) are connected to the hydraulic circuit (9). The oil inlet of the oil pump (10) is connected to the oil tank (12), and the motor (11) is connected to the oil pump (10). The flow control valve group (7) of each hydraulic control module is connected to the hydraulic circuit (9). The system control module includes a controller (19) and several sensors. The sensors, hydraulic control module and hydraulic power module are respectively connected to the controller (19). The controller (19) outputs control commands to the hydraulic control module and hydraulic power module based on the feedback from the sensors.

2. The aircraft landing gear hydraulic control system according to claim 1, characterized in that: Each hydraulic control module is equipped with a stiffness accumulator (3), which is connected to the hydraulic connection line (6). A one-way throttle valve group (4) is provided between the stiffness accumulator (3) and the hydraulic connection line (6).

3. The aircraft landing gear hydraulic control system according to claim 1, characterized in that: The rod chamber and rodless chamber of the actuator (1) are connected to each other through the valve plate on the piston. The actuator (1) has a single oil port (2). The rod chamber and rodless chamber are connected to the oil port (2). The hydraulic connection pipeline (6) is connected to the oil port (2).

4. The aircraft landing gear hydraulic control system according to claim 1, characterized in that: The flow control valve assembly (7) is equipped with a hydraulic compensation valve (71), a solenoid directional valve (72), and a check valve with pressure lock (73).

5. The aircraft landing gear hydraulic control system according to claim 1, characterized in that: The hydraulic circuit (9) of the hydraulic power module is connected in series with a check valve (13) and a solenoid valve (14). The check valve (13) is located between the oil inlet of the flow control valve group (7) and the oil outlet of the oil pump (10). The solenoid valve (14) is located between the oil return port of the flow control valve group (7) and the oil tank (12).

6. The aircraft landing gear hydraulic control system according to claim 5, characterized in that: An overflow circuit (15) is connected in parallel on the hydraulic circuit (9). One end of the overflow circuit (15) is connected between the check valve (13) and the oil pump (10), and the other end is connected between the solenoid valve (14) and the oil tank (12). An overflow valve (16) is provided on the overflow circuit (15).

7. The aircraft landing gear hydraulic control system according to claim 1, characterized in that: The sensors of the system control module include a displacement sensor (5) and a pressure sensor (8). The displacement sensor (5) is installed on the actuating rod of the actuator cylinder (1), and the pressure sensor (8) is installed on the hydraulic connection pipeline (6) between the one-way throttle valve group (4) and the flow control valve group (7).

8. The aircraft landing gear hydraulic control system according to claim 1, characterized in that: The system control module's sensors include a terrain sensor (17) and a fuselage attitude sensor (18). The terrain sensor (17) is located on the lower part of the aircraft's fuselage, and the fuselage attitude sensor (18) is located on the aircraft's fuselage or integrated into the controller (19).

9. The aircraft landing gear hydraulic control system according to claim 1, characterized in that: The hydraulic control module is a hydraulic control loop with active and passive differential control, and at least three hydraulic control modules are set up.

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