Interconnected undercarriage system, aircraft and cooperative control method thereof

Abstract

The invention provides an interconnected undercarriage system, an aircraft and a cooperative control method thereof. The interconnected undercarriage system comprises a plurality of undercarriages, each undercarriage comprises an oil gas shock absorption supporting column, and each oil gas shock absorption supporting column is provided with an oil cavity, an air cavity and a piston rod capable of stretching out and drawing back in the axial direction of the corresponding oil gas shock absorption supporting column; the hydraulic pipeline is communicated with the oil cavities of the at least two undercarriages; the at least one control valve is arranged on the hydraulic pipeline; the controller is configured to control a control valve on a hydraulic pipeline between a first oil cavity of the undercarriage in contact with the ground and a second oil cavity of at least one suspended undercarriage to be opened under the condition that at least one undercarriage is in contact with the ground and other undercarriages are suspended, so that the first oil cavity is communicated with the second oil cavity; and the oil in the first oil cavity flows to the second oil cavity to drive the piston rod of the suspended undercarriage to extend out, so that the load of the undercarriage system is balanced.

Description

Technical Field

[0001] At least one embodiment of this disclosure relates to the field of aircraft technology, and more particularly to an interconnected landing gear system, an aircraft, and a method for the coordinated control of the interconnected landing gear system. Background Technology

[0002] Aircraft main landing gear and nose landing gear are typically equipped with independent hydropneumatic shock absorber struts as a cushioning system. The basic principle of this cushioning system is that during landing impact and ground roll, the landing gear struts are compressed, the hydropneumatic fluid in the hydropneumatic chambers flows through fixed throttling orifices to generate damping, and at the same time the gas in the pneumatic chambers is compressed, thereby converting the impact kinetic energy into heat energy and dissipating it.

[0003] However, this type of independent passive buffer system has the drawback of having a single energy dissipation method, with each landing gear only able to handle the impact energy it bears. Summary of the Invention

[0004] In view of this, the present disclosure provides a method for coordinated control of an interconnected landing gear system, an aircraft, and the interconnected landing gear system, which can balance the load of the interconnected landing gear system.

[0005] As a first aspect of the present disclosure, an interconnected landing gear system is provided, comprising: a plurality of landing gears, each landing gear including a hydropneumatic strut, the hydropneumatic strut having an oil chamber, an air chamber, and a piston rod extendable and retractable along the axial direction of the hydropneumatic strut; a hydraulic line connecting the oil chambers of at least two landing gears; at least one control valve disposed in the hydraulic line; and a controller configured to, when at least one landing gear is in contact with the ground and the other landing gears are suspended, control the control valve on the hydraulic line between a first oil chamber of the landing gear in contact with the ground and a second oil chamber of the at least one suspended landing gear to open, thereby connecting the first oil chamber and the second oil chamber, allowing oil in the first oil chamber to flow to the second oil chamber, thereby driving the piston rod of the suspended landing gear to extend and balancing the load of the interconnected landing gear system.

[0006] According to embodiments of this disclosure, the interconnected landing gear system further includes: multiple sets of sensors, each configured to acquire the oil pressure of multiple oil chambers and the displacement of the piston rod; the controller includes: a judgment module, configured to determine the landing gear in contact with the ground and the suspended landing gear based on the multiple oil pressures, the multiple displacements, and combined with fuselage attitude information and acceleration information.

[0007] According to an embodiment of this disclosure, the controller further includes: a determining module configured to determine a target oil pressure range and a target displacement range for the plurality of oil chambers based on the plurality of oil pressures, the plurality of displacements, fuselage attitude information, and acceleration information, so as to determine the opening degree of at least one of the control valves based on the plurality of target oil pressure ranges and the target displacement ranges, thereby changing the flow resistance of the oil, keeping the oil pressure in the plurality of oil chambers within the target oil pressure range, and keeping the displacement of the plurality of piston rods within the target displacement range.

[0008] According to an embodiment of this disclosure, the determining module includes: a storage unit configured to store a relationship table relating flight attitude information, acceleration information, target oil pressure range, and target displacement range; and a lookup unit configured to look up the target oil pressure range and target displacement range from the relationship table based on the flight attitude information and acceleration information.

[0009] According to embodiments of this disclosure, the plurality of the aforementioned landing gears include: two main landing gears; a nose landing gear, wherein the hydraulic lines include at least a first line connecting the nose landing gear oil chamber to at least one main landing gear oil chamber, and a second line connecting the two aforementioned main landing gear oil chambers.

[0010] According to embodiments of this disclosure, the interconnected landing gear system further includes an accumulator connected to the hydraulic lines, adapted to absorb or release hydraulic oil to suppress pressure fluctuations within the hydraulic lines and temporarily store a portion of the hydraulic energy.

[0011] According to embodiments of this disclosure, the interconnected landing gear system further includes a hydraulic energy conversion unit disposed on the hydraulic pipeline, which is adapted to drive oil to flow in the hydraulic pipeline to adjust the attitude of the landing gear.

[0012] According to embodiments of this disclosure, the hydraulic energy conversion unit is further configured to convert the kinetic energy of the oil into electrical energy for storage.

[0013] As a second aspect of the present disclosure, an aircraft is provided, including: a fuselage; and any of the aforementioned interconnected landing gear systems, mounted below the fuselage.

[0014] As a third aspect of this disclosure, a cooperative control method for any of the above-described interconnected landing gear systems is provided, comprising:

[0015] Acquire pressure, piston rod displacement, and fuselage attitude and acceleration information from the oil chambers of multiple landing gears;

[0016] The landing gear in contact with the ground and the suspended landing gear are determined based on the pressure of the oil chambers of the multiple landing gears, the piston rod displacement, and the fuselage attitude and acceleration information.

[0017] When at least one landing gear is in contact with the ground while the other landing gears are suspended, a control valve on the hydraulic line between the first oil chamber of the landing gear in contact with the ground and the second oil chamber of the at least one suspended landing gear is opened, connecting the first oil chamber and the second oil chamber, allowing the oil in the first oil chamber to flow to the second oil chamber, thereby driving the piston rod of the suspended landing gear to extend and balancing the load of the interconnected landing gear system.

[0018] According to the interconnected landing gear system provided in this disclosure, at least two landing gear oil chambers are connected via hydraulic lines. When the controller detects that some landing gears are grounded while others are suspended, it immediately opens the control valves between the corresponding oil chambers. This allows high-pressure hydraulic fluid to flow from the impact-bearing grounded landing gear oil chamber to the low-pressure suspended landing gear oil chamber, actively driving the piston rod of the suspended landing gear to extend and causing the corresponding wheel to press against the ground in advance. This achieves instantaneous transfer and redistribution of impact energy between different struts, allowing the load to be shared collaboratively by multiple landing gears. This effectively balances the load distribution of the interconnected landing gear system, avoiding the risk of local overload. At the same time, by consuming the upward rebound energy generated when the main landing gear touches down, it can suppress the aircraft's jumping tendency and improve landing attitude stability and safety. Furthermore, through hydraulic interconnection and controlled flow, the interconnected landing gear system gives the landing gear the ability to make preliminary adaptive adjustments based on the real-time grounding status, laying the foundation for optimizing the overall buffer performance. Attached Figure Description

[0019] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 A schematic diagram illustrating the composition of an aircraft according to an embodiment of the present disclosure is shown.

[0021] Figure 2 A cross-sectional view of an oil-gas damping strut according to an embodiment of the present disclosure is shown schematically;

[0022] Figure 3 A schematic diagram illustrating the composition of a controller according to an embodiment of the present disclosure is shown.

[0023] Figure 4 A flowchart illustrating a cooperative control method for an interconnected landing gear system according to an embodiment of the present disclosure is shown schematically.

[0024] The annotations in the attached figures are explained as follows:

[0025] 1. Interconnected landing gear system; 11. Landing gear; 111. Main landing gear; 112. Nose landing gear; 113. Hydropneumatic shock absorber strut; 1131. Oil chamber; 1132. Air chamber; 1133. Piston rod; 12. Hydraulic pipeline; 121. First pipeline; 122. Second pipeline; 13. Control valve; 14. Controller; 141. Judgment module; 142. Determination module; 1421. Storage unit; 1422. Search unit; 15. Sensor; 16. Energy storage unit; 17. Accumulator; 18. Hydraulic energy conversion unit;

[0026] 2. Fuselage. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0029] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0030] When using expressions such as "at least one of A, B, and C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C. Similarly, when using expressions such as "at least one of A, B, or C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C.

[0031] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this disclosure.

[0032] In the process of realizing this disclosure, it was discovered that when an aircraft (e.g., an airplane) is subjected to two-point landing, hard landing, or runway inequality and non-ideal conditions, some of the oil-gas damping struts may momentarily bear impacts far exceeding the design load, while other oil-gas damping struts are under low load, resulting in low overall buffering efficiency of the landing gear system and the risk of local overload.

[0033] In addition, the damping characteristics and buffer stiffness of the oil-gas shock absorber struts are determined during the design phase and cannot be adjusted in real time according to the actual landing weight, sinking speed, attitude angle and runway conditions. This results in a significant decrease in the buffering performance of the oil-gas shock absorber struts when they deviate from the design conditions, affecting occupant comfort and structural lifespan.

[0034] Furthermore, in situations such as hard landings or tail-striking landings, the enormous impact force generated by the main landing gear touching down may give the aircraft an upward angular momentum, causing the nose landing gear to extend rapidly and release the elastic energy stored in the nose landing gear air chambers quickly, thereby triggering a "jumping" phenomenon in the entire aircraft, which poses a threat to flight safety.

[0035] In view of this, how to balance the load on the landing gear system has become an urgent technical problem to be solved.

[0036] The following detailed description, with reference to the accompanying drawings, provides a detailed explanation of an interconnected landing gear system, an aircraft, and a collaborative control method for the interconnected landing gear system provided in this disclosure. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other.

[0037] Figure 1 A schematic diagram illustrating the composition of an aircraft according to an embodiment of the present disclosure is shown. Figure 2 A cross-sectional view of an oil-gas damping strut according to an embodiment of the present disclosure is shown schematically.

[0038] A first aspect of this disclosure provides an interconnected landing gear system 1. (Refer to...) Figure 1 and Figure 2As shown, the interconnected landing gear system 1 includes multiple landing gears 11, hydraulic lines 12, at least one control valve 13, and a controller 14. Each landing gear 11 includes a hydropneumatic strut 113, which has an oil chamber 1131, an air chamber 1132, and a piston rod 1133 that is telescopic along the axial direction of the hydropneumatic strut 113. The hydraulic lines 12 connect to the oil chambers 1131 of at least two landing gears 11. At least one control valve 13 is disposed in the hydraulic lines 12. The controller 14 is configured to open a control valve 13 on a hydraulic line 12 between the first oil chamber 1131 of the landing gear 11 in contact with the ground and the second oil chamber 1131 of the at least one landing gear 11 in the air, so that the first oil chamber 1131 and the second oil chamber 1131 are connected, and the oil in the first oil chamber 1131 flows to the second oil chamber 1131 to drive the piston rod 1133 of the suspended landing gear 11 to extend, thereby balancing the load on the interconnected landing gear system 1.

[0039] As an example, the interconnected landing gear system 1 may include 3, 4, 5 or 6 landing gears 11.

[0040] According to embodiments of the present disclosure, each of the plurality of landing gears 11 includes an oil-gas damping strut 113, the interior of which is divided into an oil chamber 1131 and an air chamber 1132, and is provided with a piston rod 1133 that can extend and retract axially.

[0041] According to embodiments of this disclosure, referring to Figure 1 and Figure 2 As shown, the oil-gas damping strut 113 includes an outer cylinder, a piston rod 1133, and a floating piston.

[0042] The lower end of the outer cylinder has an opening. The piston rod 1133 includes a cylindrical body and a mating portion extending radially outward from the open end of the cylindrical body. The open end of the cylindrical body extends into the outer cylinder, and the other end of the cylindrical body opposite to the open end extends out of the outer cylinder and connects to the wheel connecting member. The lower end of the outer cylinder extends radially inward to form a limiting portion, which restricts the open end of the piston rod 1133 within the outer cylinder, preventing the piston rod 1133 from detaching from the outer cylinder.

[0043] The floating piston is movably disposed inside the outer cylinder along the axial direction of the outer cylinder, and divides the enclosed space formed by the outer cylinder and the piston rod 1133 into an oil chamber 1131 near the opening end of the piston rod 1133, and an air chamber 1132 located on the side of the floating piston opposite to the oil chamber 1131. The oil chamber 1131 is filled with hydraulic oil, and the air chamber 1132 is filled with gas (e.g., nitrogen) at a predetermined pressure.

[0044] When the landing gear 11 bears a load (such as a landing impact), the piston rod 1133 is pushed into the outer cylinder, causing the volume of the oil chamber 1131 to decrease and the oil pressure to increase accordingly. The high-pressure oil pushes the floating piston towards the gas chamber 1132, further compressing the gas in the gas chamber 1132 and converting some of the impact kinetic energy into the potential energy of the gas for storage. At the same time, the high-pressure oil is forced to flow through the throttling orifice set on the piston or the flow channel of the oil chamber 1131. The hydraulic damping generated by the narrow flow channel converts most of the impact kinetic energy into heat energy for dissipation. Through the synergistic effect of gas compression energy storage and oil throttling energy dissipation, the function of absorbing and buffering impact energy is achieved.

[0045] According to the present disclosure, controller 14 may include a flight controller (FCC) or a dedicated electronic control unit (ECU), etc.

[0046] According to embodiments of this disclosure, hydraulic lines 12 can connect the oil chambers 1131 of two landing gears 11, and control valves 13 are disposed on hydraulic lines 12. Alternatively, hydraulic lines 12 can connect the oil chambers 1131 of any two landing gears 11, and multiple control valves 13 are disposed on the hydraulic lines 12 connecting the oil chambers 1131 of any two landing gears 11. Alternatively, hydraulic lines 12 can sequentially connect the oil chambers 1131 of multiple landing gears 11, and multiple control valves 13 are disposed on the hydraulic lines 12 connecting the oil chambers 1131 of two landing gears 11.

[0047] As an example, control valve 13 may include an electro-hydraulic proportional valve or an on / off valve.

[0048] According to the interconnected landing gear system 1 of this disclosure, when a situation occurs during aircraft operation where some landing gear 11 is in contact with the ground while other landing gear 11 is not in contact with the ground, the controller 14 opens the control valve 13 on the hydraulic line 12 between the first oil chamber 1131 of the landing gear 11 in contact with the ground and the second oil chamber 1131 of the suspended landing gear 11, thereby connecting the two oil chambers 1131. Because the hydropneumatic damping strut 113 of the ground landing gear 11 is compressed, the oil pressure in the first oil chamber 1131 is higher than the oil pressure in the second oil chamber 1131 of the suspended landing gear 11. The pressure difference between the first oil chamber 1131 and the second oil chamber 1131 can drive the oil to flow from the high-pressure first oil chamber 1131 to the low-pressure second oil chamber 1131 through the hydraulic pipeline 12. The oil flowing into the second oil chamber 1131 pushes the piston rod 1133 of the suspended landing gear 11 to extend outward, causing the corresponding wheels to move towards the ground in advance and press against the ground. This realizes the active transfer and redistribution of impact energy from the high-load hydropneumatic damping strut 113 to the low-load hydropneumatic damping strut 113, so that the impact load that was originally concentrated on a local landing gear 11 can be borne by multiple landing gears 11 in a coordinated manner, thus balancing the load distribution of the entire interconnected landing gear system 1.

[0049] In addition, by actively driving the suspended landing gear 11 to make early contact with and press against the ground, the upward rebound energy that the landing gear in contact with the ground may transfer to the aircraft can be consumed, which can suppress the overall upward or jumping tendency of the aircraft and improve the safety and stability of the aircraft during the landing process.

[0050] According to embodiments of this disclosure, referring to Figure 1 and Figure 3 As shown, the interconnected landing gear system 1 also includes multiple sets of sensors 15, which are configured to acquire the oil pressure of multiple oil chambers 1131 and the displacement of the piston rod 1133. The controller 14 includes a judgment module 141, which is configured to determine the landing gear 11 in contact with the ground and the suspended landing gear 11 based on multiple oil pressures, multiple displacements, and combined with fuselage state information and acceleration information.

[0051] Each sensor group 15 may include a pressure sensor and a displacement sensor mounted on each hydraulic damping strut 113. The pressure sensor is configured to directly measure or indirectly calculate the real-time hydraulic pressure within the corresponding oil chamber 1131. The displacement sensor is configured to measure the axial extension and retraction displacement of the corresponding piston rod 1133 relative to the outer cylinder.

[0052] The airframe attitude information and acceleration information can be obtained through the inertial measurement unit (IMU) installed on the airframe 2 of the spacecraft. The inertial measurement unit (IMU) can provide real-time attitude information (such as pitch angle, roll angle, etc.) and three-axis acceleration information of the airframe 2.

[0053] In this implementation, the judgment module 141 can continuously receive and process signals from multiple sets of sensors 15 to identify the grounding status of each landing gear 11. Based on the received multiple hydraulic pressure signals, the judgment module 141 compares the absolute value of the pressure in each oil chamber 1131 and the rate of change of pressure over time (dp / dt) to preliminarily identify that the landing gear 11 corresponding to the oil chamber 1131 with a sharp increase in pressure may be under impact load and in contact with the ground. At the same time, the displacement signal of the piston rod 1133 provided by the displacement sensor 15 is used to confirm whether the corresponding oil-pneumatic shock absorber strut 113 is in the compression stroke and compression amount. Combined with the preset displacement threshold, it can help determine whether the wheels have compacted the ground.

[0054] The fuselage state information (e.g., pitch angle) and acceleration information (e.g., vertical acceleration) provided by the inertial measurement unit (IMU) can be used to determine the overall motion state of the aircraft. For example, a large positive pitch angle combined with a high acceleration signal in the main landing gear 111 area can indicate that the aircraft is in a landing attitude where the main landing gear 111 touches down first. The determination module 141 uses data fusion algorithms, such as threshold-based logical judgment or more advanced state estimation algorithms, to comprehensively analyze multi-dimensional information from pressure, displacement, attitude, and acceleration, and ultimately determines which landing gear 11s have made contact with the ground and are bearing load at a specific moment, and which landing gear 11s are still in a suspended and unloaded state. The determination of the landing gear 11s' ground contact status provides crucial input for subsequent decisions by the controller 14, such as controlling the opening and closing of specific control valves 13, ensuring that hydraulic energy distribution actions are triggered and executed based on a real and reliable system state.

[0055] In some alternative embodiments, the controller 14 can identify the contact state between the landing gear 11 and the ground by monitoring the oil pressure of each oil-pneumatic shock absorber strut 113 in real time. For example, the controller 14 can store preset pressure thresholds and pressure change rate thresholds. When the pressure value of the oil chamber 1131 corresponding to a landing gear 11 exceeds the preset pressure threshold, and the pressure change rate (dp / dt) exceeds the preset change rate threshold within a short period of time, the controller 14 can preliminarily determine that the landing gear 11 is undergoing strong impact compression and confirm that the landing gear 11 is in contact with the ground. Correspondingly, landing gear 11s with low oil pressure (close to the static pressure corresponding to the initial inflation pressure) are determined to be in a suspended state.

[0056] In some alternative embodiments, the controller 14 can identify the contact state between the landing gear 11 and the ground by real-time monitoring of the oil pressure of each hydropneumatic damping strut 113 and the displacement of the piston rod 1133. For example, when the instantaneous oil pressure of a certain hydropneumatic damping strut 113 exceeds a preset pressure threshold and the pressure change rate (dp / dt) exceeds a preset change rate threshold, the controller 14 initially determines that the hydropneumatic damping strut 113 may have encountered an impact. At this time, the controller 14 simultaneously checks the displacement signal of the piston rod 1133 of the hydropneumatic damping strut 113. If the displacement data simultaneously indicates that the piston rod 1133 is being rapidly pressed into the outer cylinder (the displacement increases and the change rate exceeds the threshold), then it is finally confirmed that the landing gear 11 is in contact with the ground. Conversely, if the oil pressure remains at a low static pressure and the piston rod 1133 shows no significant displacement, the landing gear 11 can be determined to be in a suspended state.

[0057] According to embodiments of this disclosure, referring to Figure 1 As shown, the multiple landing gears 11 include two main landing gears 111 and a nose landing gear 112. The hydraulic lines 12 include at least a first line 121 connecting the oil chamber 1131 of the nose landing gear 112 to at least one oil chamber 1131 of the main landing gear 111, and a second line 122 connecting the oil chambers 1131 of the two main landing gears 111.

[0058] The nose landing gear 112 is installed in the lower region of the fuselage 2 near the front (nose section) of the aircraft, while the main landing gear 111 is installed in the lower region slightly behind the center of gravity of the fuselage 2, or under the wing structure connecting the fuselage 2, forming a stable support layout.

[0059] The hydraulic line 12 includes a first line 121 connecting the oil chamber 1131 of the front landing gear 112 to one of the oil chambers 1131 of the main landing gear 111, and a second line 122 connecting the oil chambers 1131 of the two main landing gears 111.

[0060] Alternatively, the hydraulic line 12 includes a first line 121 connecting the hydraulic chamber 1131 of the nose landing gear 112 to the hydraulic chambers 1131 of the two main landing gears 111, and a second line 122 connecting the hydraulic chambers 1131 of the two main landing gears 111. The first line 121 can be designed to connect the hydraulic chamber 1131 of the nose landing gear 112 to the hydraulic chambers 1131 of the two main landing gears 111 simultaneously, forming a Y-shaped or T-shaped branch. Alternatively, the nose landing gear 112 can be connected to the two main landing gears 111 through two independent first lines.

[0061] Alternatively, the hydraulic line 12 may include a second line 122 connecting the two main landing gears 111, without the first line 121.

[0062] In this embodiment, different hydraulic line configurations 12 support the core functions of the interconnected landing gear system 1 under different flight phases and operating conditions. The first line 121 connects the nose landing gear to the main landing gear 111's oil chamber 1131. During landing, when the main landing gear 111 touches down first and absorbs the impact, the controller 14 can open the corresponding control valve 13 on the first line 121, allowing high-pressure hydraulic fluid to flow from the pressurized main landing gear 111's oil chamber 1131 to the nose landing gear 112's oil chamber 1131. The high-pressure hydraulic fluid pushes the nose landing gear 112's piston rod 1133 out, driving the nose wheel to press against the ground in advance. This transfers some of the impact energy from the main landing gear 111 to the nose landing gear 112, actively dissipating the rebound energy that could cause the aircraft to bounce, suppressing the hopping phenomenon, and balancing the load on the nose and main landing gear located at the front and rear of the fuselage.

[0063] The second pipe 122 connects the oil chambers 1131 of the two main landing gears 111, so that during the taxiing phase, when the aircraft rolls due to uneven runway or one main landing gear is subjected to a large impact, the controller 14 can adjust the valve on the second pipe 122 to allow the oil to flow between the oil chambers 1131 of the two main landing gears 111, thereby achieving dynamic load balance and attitude stability between the two main landing gears 111 and improving the smoothness of the aircraft taxiing.

[0064] The combination of the first pipeline 121 and the second pipeline 122 constructs an interconnected hydraulic network of hydraulic pipelines 12, enabling energy to be transferred and distributed in multiple dimensions, including front-to-back and left-to-right. The control valve 13 controls the on / off state and flow of the pipelines, allowing the hydraulic network to switch from a completely independent mode to a fully interconnected mode, or to an intermediate state of interconnection of multiple parts. This provides the interconnected landing gear system 1 with reconfigurable adaptive capabilities, enabling it to cope with various complex scenarios such as landing impacts and bumpy skidding.

[0065] According to embodiments of this disclosure, referring to Figure 1 and Figure 3 As shown, the controller 14 also includes a determination module 142, which is configured to determine the target oil pressure range and target displacement range of multiple oil chambers 1131 based on multiple oil pressures, multiple displacements, fuselage state information and acceleration, so as to determine the opening degree of at least one control valve 13 based on the multiple target oil pressure ranges and target displacement ranges, thereby changing the flow resistance of the oil, keeping the oil pressure in the multiple oil chambers 1131 within the target oil pressure range, and keeping the displacement of the multiple piston rods 1133 within the target displacement range.

[0066] As an example, target pressure and target travel can be obtained based on flight attitude and acceleration using fuzzy algorithms and a database. The database can be stored within the controller 14. The database can be the optimization of the oil pressure and travel of the oil-gas damping strut 113 through simulation and landing tests under several boundary / typical landing attitudes. Then, through intelligent learning, all optimal target oil pressure ranges and target displacement ranges within the variable domain are obtained as the database for fuzzy control, and then intelligent calculation (i.e., the standard process of fuzzy inference) is performed.

[0067] The database stores the reference pressure of each oil chamber 1131 and the reference stroke of the piston rod 1133, which are obtained through simulation and experimental optimization under different typical landing weights, landing attitudes and runway conditions, and correspond to the global optimal cushioning performance of the interconnected landing gear system 1.

[0068] The determination module 142 matches and infers the real-time perceived fuzzy chemical conditions (e.g., medium landing weight, large pitch angle landing, bumpy runway, etc.) with the database. After defuzzification, it generates target oil pressure range and target displacement range for each oil chamber 1131 that are adapted to the global requirements at this moment.

[0069] In some other illustrative embodiments of this disclosure, the determining module 142 may employ a nonlinear mapping model based on a deep neural network. This nonlinear mapping model is trained using a large amount of historical optimal buffer data and can directly map the current sensor 15 data vector to the recommended target parameter range.

[0070] In this implementation, the controller 14 receives data from multi-dimensional sensors 15 (multiple oil pressures, multiple displacements, fuselage state information, and acceleration information) and the determination module 142, providing specific performance adjustment targets that change over time and under different operating conditions. These dynamically generated target oil pressure ranges and target displacement ranges represent the ideal buffer state range for achieving optimal load balance, buffer efficiency, and attitude stability under the current specific flight conditions (such as specific landing weight, impact velocity, runway smoothness, and fuselage attitude).

[0071] The controller 14 compares the actual oil pressure of each oil chamber 1131 with the corresponding target oil pressure range, and the actual displacement of each piston rod 1133 with the corresponding target displacement range, thereby determining the control signals that need to be applied to each control valve 13 on the interconnected hydraulic pipeline 12. The control valve 13 responds to the control signals by adjusting its opening, changing the flow resistance of the oil in the interconnected pipeline. By increasing or decreasing the flow resistance, the speed and flow rate of the high-pressure oil chamber 1131 draining into the low-pressure oil chamber 1131 can be actively adjusted, thereby precisely controlling the pressure build-up and release process in each oil chamber 1131, as well as the speed and position of the piston rod 1133's extension and retraction.

[0072] The aforementioned closed-loop control process drives the actual oil pressure of each oil chamber 1131 to be stabilized within its respective target range, while the actual displacement of each piston rod 1133 is also maintained within its respective target range. In this way, the system transcends simple on / off energy transfer, achieving continuous, coordinated, and adaptive adjustment of the buffer stiffness and damping characteristics of multiple landing gear struts 11. This enables the entire interconnected landing gear system 1 to dynamically adapt to complex landing and taxiing conditions, always tending towards globally optimal buffering and stability performance.

[0073] According to embodiments of this disclosure, referring to Figure 1 and Figure 3 As shown, the determining module 142 includes a storage unit 1421 and a lookup unit 1422. The storage unit 1421 is configured to store a relationship table relating flight attitude information, acceleration information, target oil pressure range, and target displacement range. The lookup unit 1422 is configured to look up the target oil pressure range and target displacement range from the relationship table based on the flight attitude information and acceleration information.

[0074] In some illustrative embodiments of this disclosure, the determination module 142 of the controller 14 includes a storage unit 1421 and a lookup unit 1422. The storage unit 1421 is configured to store one or more preset relationship tables. These relationship tables establish a mapping relationship between different flight attitude information (such as pitch angle and roll angle), different acceleration information (such as vertical acceleration), and the target oil pressure range and target displacement range corresponding to each oil-gas damping strut 113. The target oil pressure range and target displacement range can be interval values ​​set for the oil chamber 1131 and piston rod 1133 of each oil-gas damping strut 113 respectively.

[0075] The lookup unit 1422 is configured to receive flight attitude information and acceleration information obtained from real-time monitoring, match the flight attitude information and acceleration information with the index conditions in the relation table, and thus quickly retrieve the target oil pressure range and target displacement range applicable under the current working conditions.

[0076] In other illustrative embodiments of this disclosure, the relationship table can be constructed based on a large amount of flight test data, simulation data or theoretical models, and typical flight states (such as normal two-point landing, hard landing, turbulent run, etc.) can be associated with the pressure and displacement parameters of the optimized interconnected landing gear system 1.

[0077] The lookup unit 1422 can be designed to operate based on nearest neighbor matching or interpolation algorithms to process real-time sensor 15 data between preset index points. To ensure reliability, the storage unit 1421 can also store multiple sets of relation tables, each corresponding to different aircraft gross weights, runway classes, or system operating modes. The lookup unit 1422 selects and activates the appropriate set based on the auxiliary input signal.

[0078] As an example, an example of control parameters for an interconnected landing gear system 1 based on predetermined operating conditions is provided, as shown in Table 1. Table 1 illustrates the target pressure range and target travel range of each landing gear 11's hydropneumatic damping strut 113 under different typical flight attitudes, set to optimize the overall performance of the interconnected landing gear system 1. It should be understood that the values ​​in Table 1 can be derived based on simulation and experimental optimization or experience, and can serve as the basis for determining the target range in the control strategy.

[0079] Table 1

[0080]

[0081] It should be noted that the target pressure values ​​in Table 1 can be representative values ​​within the target pressure range, and the target displacement values ​​can be representative values ​​within the target displacement range.

[0082] Referring to Table 1, for a normal landing attitude, the target settings of controller 14 focus on providing standard cushioning force. At this time, the target pressure of the main landing gear 111 is set to a relatively balanced medium value, and the target travel is within a moderate range, which is intended to absorb conventional impact energy; the target pressure of the nose landing gear 112 is lower, and the target travel is longer, which together ensures that the aircraft touches down smoothly and achieves a comfortable initial taxi.

[0083] In a horizontal landing attitude, the aircraft's pitch angle is close to zero degrees, and the nose landing gear 112 and the main landing gear 111 touch down almost simultaneously. To cope with the potentially larger initial load on the nose landing gear 112, the target pressure value of the nose landing gear 112 is set higher than in the normal attitude, along with a larger target travel value, in order to provide sufficient support and cushioning for the front of the fuselage 2 and avoid nose landing gear overload.

[0084] For high descent rates / heavy landing attitudes, the high descent velocity (acceleration) brings enormous impact energy. At this time, the target pressure value of the main landing gear 111 is set at a high level to establish high initial support stiffness to resist strong impacts; at the same time, its target stroke value is also set at a large value to reserve a longer buffer stroke for oil flow energy consumption and gas compression, ensuring that energy is effectively absorbed.

[0085] When the aircraft is in a tail-down landing attitude, it touches down at a large pitch angle, and the load is significantly transferred to the main landing gear 111. Therefore, the target pressure value of the main landing gear 111 is set to a high level, while its target travel value is relatively shortened, prompting the main landing gear 111 to quickly enter a high-pressure support state, providing greater rigid support force required to resist the tail-down tendency and stabilize the attitude of the fuselage 2.

[0086] In a single-sided landing attitude, the aircraft touches down with a certain roll angle, resulting in uneven load distribution on the two main landing gears 111. The controller 14 compensates for this by setting asymmetrical target parameters: the target pressure and target stroke values ​​of the main landing gear 111 on the heavier load side are both greater than those on the lighter load side. This parameter setting guides the hydraulic fluid and load to be distributed to a specific side, generating a compensating torque to maintain the fuselage 2 in a level position and stability in the taxiing direction.

[0087] During sustained taxiing turbulence, the aircraft's attitude parameters fluctuate around a baseline. In this situation, the target pressure and target travel of each strut are set to a dynamic range rather than fixed values. The system makes real-time, high-frequency fine-tuning based on road surface feedback, allowing the strut parameters to track changes within this range. This optimizes the filtering capability against continuous turbulence, improving ride comfort and handling stability during taxiing.

[0088] The inertial measurement unit collects flight attitude and acceleration information in real time and inputs it to the controller. The controller, based on the information in Table 1 stored in the storage unit, determines the target oil pressure range and the target displacement range of the piston rod required for each oil-gas damping strut.

[0089] Pressure sensors and displacement sensors deployed on each oil and gas damping support measure the real-time pressure value of each oil chamber and the real-time displacement value of the piston rod, respectively.

[0090] The controller continuously compares the real-time target parameters (target oil pressure range and target displacement range) with the measured parameters (real-time pressure value and real-time displacement value) and generates control decisions based on the comparison results. If the measured parameters are lower than the target parameters, it is determined that the oil chamber pressure needs to be increased, and the decision is to replenish oil in the oil chamber (pressure replenishment); if the actual value is higher than the target range, it is determined that the oil chamber pressure needs to be reduced, and the decision is to release part of the oil in the oil chamber (pressure relief) to reduce the deviation between the actual state and the ideal target.

[0091] The aforementioned control decisions are converted into specific electrical signal commands, which are output to control valves installed in the interconnected hydraulic lines. The control valves change their opening degree according to the electrical signal commands, thereby regulating the flow of oil into or out of specific oil chambers, achieving proactive and precise control of the oil chamber pressure and piston rod stroke. This perception-decision-execution process continuously cycles, forming a dynamic closed-loop feedback control loop, until the measured pressure and stroke values ​​of each hydropneumatic damping strut stabilize within the target allowable error range. At this point, the interconnected landing gear system reaches its optimal or near-optimal adaptive buffer state under the current operating conditions.

[0092] In this implementation, the predefined relation table provided by the storage unit 1421 stores the set of optimal or suboptimal operating points for different known operating conditions, avoiding the delays and uncertainties that may be caused by complex online optimization calculations in the control algorithm during critical flight phases. The lookup unit 1422 directly reads the corresponding target range from the relation table based on real-time sensed fuselage attitude and acceleration information. This process has low computational load and fast response. The target range obtained in this way provides a clear and reliable setpoint for the subsequent calculation of the opening of the control valve 13. The controller 14 calculates the opening adjustment of the control valve 13 by comparing the actual oil pressure of each oil chamber 1131 with the found target oil pressure range, and the actual displacement of each piston rod 1133 with the target displacement range, thereby changing the flow resistance of the oil in the interconnected pipeline. This enables the system to guide the pressure and displacement states of each strut to quickly approach the preset optimization range for the current specific flight state, thereby achieving rapid and adaptive load distribution and attitude stability control under different landing conditions and taxiing states, while ensuring the determinism and real-time performance of the interconnected landing gear system 1.

[0093] According to embodiments of this disclosure, the interconnected landing gear system 1 further includes an accumulator 17. The accumulator 17 is connected to the hydraulic line 12 and is adapted to absorb or release hydraulic oil to suppress pressure fluctuations within the hydraulic line 12 and temporarily store a portion of the hydraulic energy.

[0094] In some illustrative embodiments of this disclosure, the accumulator 17 may be installed on the main trunk or a critical branch node of the hydraulic line 12. The accumulator 17 may contain a pre-charged nitrogen chamber (such as a bladder or piston type) isolated from the hydraulic oil in the line by an isolation element (such as a bladder or piston). The pre-charge pressure within the chamber of the accumulator 17 is set according to the system operating pressure range.

[0095] In this implementation, the accumulator 17, acting as a passive hydraulic chamber, plays a crucial dynamic regulating role in the hydraulic pipeline 12 through the compressibility of the gas inside the accumulator 17. When a transient high-pressure pulsation occurs in the pipeline due to a sudden load on the landing gear 11, some of the high-pressure oil can flow into the accumulator 17, compressing the gas inside and absorbing this peak pressure energy. This effectively suppresses pressure shocks and fluctuations within the pipeline, protecting components such as pipelines and valves. Conversely, when the pipeline pressure drops momentarily due to the transfer of oil to the low-load support, the compressed gas inside the accumulator 17 expands, releasing the stored oil back into the pipeline to replenish the flow, helping to maintain the relative stability of the pipeline pressure and the continuity of oil flow.

[0096] The energy absorption and release process essentially filters and buffers pressure fluctuations in the hydraulic system. By absorbing and temporarily storing some of the impact energy, the accumulator 17 not only smooths the pressure in the interconnected landing gear system 1 but also creates more stable operating conditions for the controller 14 to implement precise flow and pressure regulation. Furthermore, in extreme cases, such as when the independent buffer function of a strut partially fails, the energy stored in the accumulator 17 can serve as a temporary supplementary buffer medium, providing limited additional support through the interconnected piping, thereby improving the robustness and safety redundancy of the entire interconnected landing gear system 1 to some extent.

[0097] According to embodiments of this disclosure, the interconnected landing gear system 1 further includes a hydraulic energy conversion unit 18. The hydraulic energy conversion unit 18 is disposed on a hydraulic line 12 and is adapted to drive oil to flow in the hydraulic line 12 to adjust the attitude of the landing gear 11.

[0098] According to embodiments of this disclosure, the hydraulic energy conversion unit 18 is further configured to convert the kinetic energy of the oil into electrical energy for storage.

[0099] In some illustrative embodiments of this disclosure, the hydraulic energy conversion unit 18 is a reversible positive displacement hydraulic machine, such as an axial piston pump or a gear pump. The inlet and outlet ports of the hydraulic energy conversion unit 18 are connected to the main trunk or key branches of the hydraulic pipeline 12. The hydraulic energy conversion unit 18 is connected to a motor or generator via a drive shaft. The motor or generator is controlled by a controller 14 and can switch between electric mode and generator mode. Based on the signals from the sensor 15 and the current operating mode requirements, the controller 14 sends torque and speed commands to the motor or generator, thereby driving the hydraulic energy conversion unit 18 to work as a pump or as a motor.

[0100] In this implementation, the hydraulic energy conversion unit 18 provides active energy management and attitude adjustment capabilities for the interconnected landing gear system 1 through its reversible operating characteristics. When the controller 14 determines that active adjustment of hydraulic fluid distribution is needed to optimize attitude, such as when pre-pressurizing the landing gear 112 before landing or when actively suppressing airframe vibrations in a specific direction during takeoff, the controller 14 controls the motor to drive the hydraulic energy conversion unit 18 as a pump. At this time, the hydraulic energy conversion unit 18 draws in hydraulic fluid from the hydraulic lines 12, pressurizes and discharges it, actively driving the fluid to flow in the interconnected lines in a specified direction, generating the required pressure difference and flow rate, thereby achieving active extension or compression of specific landing gear 11 struts, and thus precisely adjusting the aircraft's pitch or roll attitude. Conversely, during landing cushioning or turbulent takeoff, when the fluid flows naturally in the hydraulic lines 12 due to the pressure difference, the controller 14 can control the hydraulic energy conversion unit 18 to operate as a motor. High-pressure oil flowing through the hydraulic energy conversion unit 18 drives the unit to rotate, which in turn drives the generator to generate electricity, converting some of the hydraulic kinetic energy into electrical energy for storage. Through this bidirectional working mode, the hydraulic energy conversion unit 18 not only expands the active attitude control dimension of the interconnected landing gear system 1, but also realizes the recovery of some impact energy, thereby improving the overall energy efficiency of the interconnected landing gear system 1.

[0101] As an example, during the landing phase, the aircraft (e.g., a plane) lands at a large pitch angle, with the main landing gear 111 touching down first and absorbing most of the impact. The controller 14 detects a sudden increase in hydraulic pressure in the main landing gear 111 while the hydraulic pressure in the nose landing gear 112 is very low. The controller 14 immediately opens the control valve 13 on the hydraulic line between the main landing gear 111 and the nose landing gear 112. High-pressure hydraulic fluid flows from the pressurized main landing gear 111's oil chamber 1131 through the hydraulic line 12 into the nose landing gear 112's oil chamber 1131, pushing the piston rod 1133 of the nose landing gear 112 to extend, causing the nose landing gear 112 to "pre-compress" and make earlier contact with the ground. This achieves the transfer of energy from the high-load strut to the low-load strut, avoiding overload of the main landing gear 111 and allowing the aircraft's attitude to stabilize more quickly, effectively preventing "jumping."

[0102] As an example, during the takeoff phase, the aircraft taxis on a bumpy or uneven runway. The controller 14 dynamically adjusts the valve openings of each hydraulic line 12 based on the compression of each hydraulic shock absorber strut 113 and the attitude of the fuselage 2. When one main landing gear 111 passes over the protrusion, some of the high-pressure hydraulic fluid can flow to the other main landing gear 111 or the nose landing gear 112, which is equivalent to providing the function of an "active stabilizer bar" for the entire interconnected landing gear system 1, improving the smoothness and stability of the takeoff.

[0103] As an example, during landing cushioning and runway shock absorption, hydraulic fluid flows at high speed in hydraulic lines 12. Controller 14 controls hydraulic energy conversion unit 18 to operate as a "motor," driving generator to convert some of the impact kinetic energy that would otherwise be converted into heat into electrical energy, which is stored in the aircraft's energy storage unit 16 (e.g., a battery) to power onboard equipment and achieve energy conservation.

[0104] As a second aspect of the present disclosure, an aircraft is provided, with reference to Figure 1 As shown, the aircraft includes a fuselage 2 and any of the aforementioned interconnected landing gear systems 1. The interconnected landing gear system 1 is mounted below the fuselage 2.

[0105] Aircraft can include any type of aircraft, such as fixed-wing aircraft, gliders, fixed-wing, rotary-wing, or hybrid-layout drones.

[0106] In this embodiment, when the main landing gear 111 contacts the ground first, the controller 14 can open the control valve 13 between the main landing gear 111 and the oil chamber 1131 of the nose landing gear 112. High-pressure hydraulic fluid flows from the impacted main landing gear 111 oil chamber 1131 to the nose landing gear 112 oil chamber 1131, driving the nose landing gear 112 piston rod 1133 to extend actively, causing the nose wheel of the nose landing gear 112 to press against the runway in advance, thus buffering the impact and suppressing nose-up.

[0107] During the taxiing phase, if the unevenness of the runway leads to uneven load, the controller 14 can continuously adjust the valve opening of the control valve 13 on each hydraulic line 12 to dynamically manage the distribution and pressure of oil in each oil chamber 1131, and optimize the buffer stiffness and damping of each oil-air damping strut 113 in real time to maintain the stability of the fuselage 2 and the comfort of the crew.

[0108] Figure 4 A flowchart illustrating a cooperative control method for an interconnected landing gear system according to an embodiment of the present disclosure is shown schematically.

[0109] As a third aspect of this disclosure, a cooperative control method for any of the above-described interconnected landing gear systems 1 is provided, referring to... Figure 4 As shown, the cooperative control method includes operations S400 to S420.

[0110] The S400 system acquires information on the pressure of multiple landing gear oil chambers, piston rod displacement, and fuselage attitude and acceleration.

[0111] When operating the S410, the landing gear in contact with the ground and the suspended landing gear are determined based on the pressure of the oil chambers of multiple landing gears, the piston rod displacement, and the fuselage attitude and acceleration information.

[0112] In operation S420, when at least one landing gear is in contact with the ground while the other landing gears are suspended, the control valve on the hydraulic line between the first oil chamber of the landing gear in contact with the ground and the second oil chamber of the at least one suspended landing gear is opened, so that the first oil chamber and the second oil chamber are connected, and the oil in the first oil chamber flows to the second oil chamber to drive the piston rod of the suspended landing gear to extend, thereby balancing the load of the interconnected landing gear system.

[0113] In this embodiment, by transferring a portion of the hydraulic energy absorbed by the hydropneumatic damping strut 113 of the grounded landing gear 11 to the hydropneumatic damping strut 113 of the suspended landing gear 11 via hydraulic fluid, and converting it into mechanical energy that pushes the piston rod 1133 of the suspended landing gear 11 to extend, the impact kinetic energy is transferred and redistributed in real time between different structural positions at the physical level. This allows the entire interconnected landing gear system 1 to work collaboratively, dispersing concentrated loads and balancing the overall stress on the system, thus avoiding the risk of local structural overload. At the same time, the early extension and grounding action of the suspended landing gear 11 (especially the nose landing gear 112) actively consumes the vertical momentum and pitch momentum transferred to the fuselage when the main landing gear 111 touches down, suppressing the tendency of the aircraft to rise or bounce from the root of dynamics. This transforms the traditional passive and independent buffering mode into an active and interconnected collaborative buffering mode, improving landing safety, structural reliability, and crew comfort.

[0114] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. An interconnected landing gear system, characterized in that, include: Multiple landing gears, each landing gear including a hydropneumatic damping strut, the hydropneumatic damping strut having an oil chamber, an air chamber and a piston rod that can extend and retract along the axial direction of the hydropneumatic damping strut; Hydraulic lines connect the oil chambers of at least two landing gears; At least one control valve is provided in the hydraulic line; The controller is configured to, when at least one landing gear is in contact with the ground and the other landing gears are suspended, control the opening of a control valve on the hydraulic line between the first oil chamber of the landing gear in contact with the ground and the second oil chamber of the at least one suspended landing gear, so as to connect the first oil chamber and the second oil chamber, and allow the oil in the first oil chamber to flow to the second oil chamber, thereby driving the piston rod of the suspended landing gear to extend and balance the load of the interconnected landing gear system.

2. The interconnected landing gear system according to claim 1, characterized in that, Also includes: Multiple sets of sensors are configured to acquire the oil pressure of multiple oil chambers and the displacement of the piston rod; The controller includes: The determination module is configured to determine the landing gear in contact with the ground and the landing gear suspended in the air based on multiple hydraulic pressures, multiple displacements, and combined with fuselage attitude information and acceleration information.

3. The interconnected landing gear system according to claim 2, characterized in that, The controller also includes: The determining module is configured to determine a target oil pressure range and a target displacement range for a plurality of oil chambers based on a plurality of oil pressures, a plurality of displacements, fuselage attitude information, and acceleration information, so as to determine the opening degree of at least one of the control valves based on the plurality of target oil pressure ranges and the target displacement ranges, thereby changing the flow resistance of the oil, keeping the oil pressure in the plurality of oil chambers within the target oil pressure range, and keeping the displacement of the plurality of piston rods within the target displacement range.

4. The interconnected landing gear system according to claim 3, characterized in that, The determining module includes: The storage unit is configured to store a relationship table containing flight attitude information, acceleration information, target oil pressure range, and target displacement range. The lookup unit is configured to look up the target oil pressure range and target displacement range from the relation table based on the flight attitude information and acceleration information.

5. The interconnected landing gear system according to claim 1, characterized in that, The plurality of said landing gears include: Two main landing gears; The nose landing gear, wherein the hydraulic lines include at least a first line connecting the nose landing gear oil chamber to at least one main landing gear oil chamber, and a second line connecting the two main landing gear oil chambers.

6. The interconnected landing gear system according to claim 1, characterized in that, Also includes: An accumulator, connected to the hydraulic line, is used to absorb or release hydraulic oil to suppress pressure fluctuations within the hydraulic line and temporarily store some hydraulic energy.

7. The interconnected landing gear system according to claim 1, characterized in that, Also includes: A hydraulic energy conversion unit is installed on the hydraulic pipeline and is suitable for driving oil to flow in the hydraulic pipeline to adjust the attitude of the landing gear.

8. The interconnected landing gear system according to claim 7, characterized in that, The hydraulic energy conversion unit is also configured to convert the kinetic energy of the oil into electrical energy for storage.

9. An aircraft, characterized in that, include: body; The interconnected landing gear system as described in any one of claims 1-8 is installed under the fuselage.

10. A cooperative control method for an interconnected landing gear system according to any one of claims 1-8, characterized in that, include: Acquire pressure, piston rod displacement, and fuselage attitude and acceleration information from the oil chambers of multiple landing gears; The landing gear in contact with the ground and the suspended landing gear are determined based on the pressure of the oil chambers of the multiple landing gears, the piston rod displacement, and the fuselage attitude and acceleration information. When at least one landing gear is in contact with the ground while the other landing gears are suspended, a control valve on the hydraulic line between the first oil chamber of the landing gear in contact with the ground and the second oil chamber of the at least one suspended landing gear is opened, connecting the first oil chamber and the second oil chamber, allowing the oil in the first oil chamber to flow to the second oil chamber, thereby driving the piston rod of the suspended landing gear to extend and balancing the load of the interconnected landing gear system.

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