An aircraft water landing system and stability augmentation control method thereof

Abstract

This invention discloses a water landing system for aircraft and its stabilization control method, belonging to the field of takeoff, landing, and attitude control technology for sea-skimming aircraft. The system includes a retractable water skid assembly, an air cushion-assisted landing assembly, and a coupling control system. The water skid assembly comprises a water skid body, a folding rod assembly, an upper guide rail, a slider, and an electric actuator. The electric actuator drives the folding rod assembly to extend or retract, thereby extending or retracting the water skid body. The air cushion-assisted landing assembly includes an air cushion body and an inflation source for inflation before water contact. The coupling control system is connected to the electric actuator to control the extension and retraction. This system can retract the water skid during flight to reduce drag, and extend it during landing to provide stable support. Simultaneously, the air cushion buffers the impact, achieving a safe and controllable water landing.

Description

Technical Field

[0001] This invention relates to the field of take-off and landing and attitude control technology for sea-skimming aircraft, and in particular to a water landing system for an aircraft and its stabilization control method. Background Technology

[0002] In the fields of aerospace and maritime vehicles, sea-skimming aircraft need to switch between various operating conditions, including high-altitude flight, sea-skimming flight, sea-surface gliding, and sea-surface landing. Although traditional fixed floats or fixed water skids can provide effective support during the sea-surface landing phase, they are constantly exposed to airflow during the high-altitude flight phase, generating significant additional drag and limiting the aircraft's range and flight efficiency.

[0003] Meanwhile, in sea-skimming aircraft operating in close proximity to the sea, the altitude margin, time window, and maneuverability available for troubleshooting and emergency landings are extremely limited should a power anomaly, attitude deviation, or navigation failure occur. By placing the takeoff platform at a certain altitude, the aircraft can gain altitude margin relative to the sea surface after takeoff, providing a crucial safety window for attitude recovery, trajectory adjustment, and emergency landing on the sea surface.

[0004] Furthermore, during sea landing, the impact of waves from one side can cause a sudden increase in load on or lift of the skid plate on that side, leading to a sudden roll tendency in the aircraft. At this time, relying solely on ailerons for attitude correction is insufficient due to the decreased efficiency and delayed response of aerodynamic control surfaces at the moment of water contact, resulting in inadequate roll stability margin and making it difficult to meet the control requirements for a safe landing. Summary of the Invention

[0005] The purpose of this invention is to provide an aircraft water landing system and its stability augmentation control method to solve the problems of existing solutions, such as large additional drag during the high-altitude cruise phase, insufficient utilization of emergency response altitude margin, poor roll stability under unilateral disturbances, and weak water impact suppression capability, so as to realize multi-stage adaptive switching of aircraft morphology and stability augmentation control throughout the water landing process.

[0006] As a first aspect of the present invention, the present invention provides an aircraft water landing system, including a retractable water skid assembly, an air cushion-assisted landing assembly, and a coupling control system; the retractable water skid assembly is disposed under the aircraft and includes a water skid body, a folding rod assembly, an upper guide rail, a pivot connecting slider, and an electric actuator; the upper guide rail is fixedly connected to the aircraft's airframe load-bearing structure, the pivot connecting slider is slidably engaged with the upper guide rail, one end of the folding rod assembly is connected to the upper guide rail via the pivot connecting slider, and the other end of the folding rod assembly is connected to the water skid body; the electric actuator is used to drive the folding rod assembly to unfold or retract, thereby causing the water skid body to extend or retract; the air cushion-assisted landing assembly is disposed under the aircraft's belly and includes an air cushion bladder and an inflation source; the inflation source is used to inflate the air cushion bladder; the coupling control system is connected to the retractable water skid assembly to control the extension and retraction of the water skid body.

[0007] Optionally, the folding rod assembly includes a first folding rod, a second folding rod, and a folding rod pivot. The first folding rod and the second folding rod are cross-hinged through the folding rod pivot to form a scissor-type folding rod assembly.

[0008] Optionally, the retractable water ski assembly further includes a lower guide rail and a lower guide rail bearing. The lower guide rail is fixedly disposed on the upper surface of the water ski body, and the lower guide rail bearing slides or rolls with the lower guide rail. The other end of the folding rod assembly is connected to the lower guide rail through the lower guide rail bearing.

[0009] Optionally, the electric actuator cylinder is provided with a self-locking mechanism, which is used to lock the position of the telescopic rod of the electric actuator cylinder after the water skid plate body is extended or retracted into place.

[0010] Optionally, the surface of the air cushion body is provided with air holes, which are used to release air outward when the air cushion body comes into contact with water, forming an air film buffer zone between the air cushion body and the water surface.

[0011] Optionally, the air cushion-assisted landing assembly further includes a pressurization chamber disposed on a gas pipeline between the inflation source and the air cushion body, for establishing a predetermined pressure before the air cushion body is inflated.

[0012] Optionally, the retractable water skid assemblies are symmetrically arranged on the left and right sides of the aircraft, and the retractable water skid assemblies on the left and right sides are independent of each other and are respectively communicatively connected to the coupling control system.

[0013] Optionally, the retractable water ski assembly further includes a position sensor, which is disposed at the upper guide rail, the electric actuator, or the folding rod assembly, for detecting the telescopic displacement of the water ski body.

[0014] Optionally, the retractable water ski assembly further includes a load sensor, which is disposed on the water ski body, the folding rod assembly or their connecting parts, and is used to detect the water surface load borne by the water ski body.

[0015] As a second aspect of the present invention, the present invention provides a stabilization control method for an aircraft water landing system, based on the aircraft water landing system described in the first aspect above, the method comprising the following steps: During the high-altitude flight phase, the electric actuator retracts through the coupling control system, causing the folding rod assembly to collapse and the main body of the water skid plate to be stored under the aircraft fuselage. During the landing preparation phase, the electric actuator cylinder is extended by the coupling control system, which drives the rotating shaft connecting slider to move along the upper guide rail, thereby unfolding the folding rod assembly and causing the main body of the water skid plate to extend downward to the working height. During the landing and water contact phase, the air source is controlled to inflate the air cushion bag, causing the air cushion bag to deploy and buffer the impact of water contact. Before and after contact with water, the coupling control system coordinates and controls the extension of the left and right sides of the water skid body according to the attitude information of the aircraft and the load information of the water skid body, so as to suppress roll disturbance.

[0016] Furthermore, the coupling control system sends different extension and retraction commands to the electric actuators on the left and right sides respectively based on the load difference and displacement difference of the main bodies of the left and right water skids, so that the main bodies of the left and right water skids form different extension amounts, generating a roll restoring torque opposite to the direction of disturbance.

[0017] Furthermore, by adjusting the air supply of the inflation source and the exhaust rate of the air cushion, the support pressure of the air cushion is changed, so that the disturbed side maintains a higher support pressure and the other side reduces the support pressure during unilateral disturbance.

[0018] Furthermore, at the moment of water contact, the air cushion and differential extension and retraction of the water skids are the main means of shock absorption and attitude maintenance; during the gliding phase after water contact, the combined action of differential extension and retraction of the water skids and deflection of the ailerons is used for attitude stabilization.

[0019] Furthermore, after the aircraft takes off from the safe altitude takeoff platform, the coupling control system determines whether the conditions for the water skid to extend are met based on the flight altitude, flight speed, attitude angle and landing command. If the conditions for extension are met, the system controls the electric actuator to extend.

[0020] Compared with the prior art, the present invention discloses at least the following beneficial effects: This invention achieves attitude control and impact mitigation for the entire water landing process by combining a retractable water skid assembly with an air cushion-assisted landing assembly. Specifically, the water skid assembly utilizes the linkage of a folding rod group, an upper guide rail, and an electric actuator to retract the main body of the water skid under the fuselage during high-altitude flight, thereby effectively reducing cruise drag and improving flight economy. During the landing preparation phase, the electric actuator drives the folding rod group to unfold, causing the main body of the water skid to extend downwards to the working height, providing a stable hydrodynamic support surface for water contact. Simultaneously, the air cushion bladder located under the fuselage is rapidly inflated and unfolded by an air source before water contact. The pores on its surface expel air upon contact with the water surface, forming an air film buffer zone between the bladder and the water surface, which can significantly absorb and disperse vertical impact energy, reducing the peak overload transmitted to the fuselage. Based on this, the coupling control system coordinates the extension and retraction of the water skid and the inflation of the air cushion, enabling the system to adaptively switch modes in different flight phases. This ensures low drag characteristics during high-altitude cruise and enhances buffering capacity and attitude stability upon landing and water contact. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall takeoff and landing process of an aircraft provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the storage layout of the aircraft during the flight phase according to an embodiment of the present invention; Figure 3 This is a front view of the retractable water skid assembly in an embodiment of the present invention; Figure 4 This is an isometric view of the retractable water skid assembly in an embodiment of the present invention; Figure 5 This is a top view of the retractable water skid assembly in an embodiment of the present invention: Figure 6 This is a schematic diagram of the structure of the air cushion-assisted landing component in an embodiment of the present invention; Figure 7 This is a schematic diagram of the differential extension and retraction of the slickboard, the air cushion pressure adjustment, and the coordinated deflection of the aileron under unilateral disturbance conditions according to an embodiment of the present invention. Reference numerals: 1. Aircraft; 2. Water skid body; 3. Lower guide rail; 4. Lower guide rail bearing; 5. Folding rod pivot; 6. First folding rod; 7. Second folding rod; 8. Upper guide rail; 9. Pivot connecting slider; 10. Pivot base; 11. Electric actuator; 12. Position sensor; 13. Load sensor; 14. Safe altitude takeoff platform; 15. Aileron; 16. Air cushion body; 17. Inflation source; 18. Air vent; 19. Pressurization chamber. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Reference Figures 1 to 7 As shown, this embodiment of the invention provides an aircraft water landing system, which includes a retractable water skid assembly, an air cushion-assisted landing assembly, and a coupling control system disposed below the aircraft 1.

[0026] like Figure 1 As shown, the aircraft water landing system of this embodiment requires the use of a safe altitude takeoff platform 14 to complete the landing maneuver on the water surface. This safe altitude takeoff platform 14 is located at a predetermined altitude, such as a mountaintop, an island or reef, a shore-based platform, or an artificial elevated platform. After taking off from this safe altitude takeoff platform 14, the aircraft 1 can obtain a height margin relative to the sea surface, providing a safe window for attitude recovery and trajectory adjustment for subsequent emergency landings, thereby improving the safety of fault handling.

[0027] In this embodiment, the retractable water ski assembly is located below the aircraft 1, and specifically includes a water ski body 2, a lower guide rail 3, a lower guide rail bearing 4, a folding rod shaft 5, a first folding rod 6, a second folding rod 7, an upper guide rail 8, a shaft connecting slider 9, a shaft base 10, and an electric actuator 11.

[0028] Based on the above embodiments, the upper guide rail 8 is fixedly connected to the underside of the wing of the aircraft 1 or other load-bearing structure, extending longitudinally or laterally along the aircraft. The pivot connecting slider 9 is slidably engaged with the upper guide rail 8, and can reciprocate along the guiding direction of the upper guide rail 8. The lower guide rail 3 is fixedly installed on the upper surface of the water skid plate body 2, and the lower guide rail bearing 4 is in rolling or sliding engagement with the lower guide rail 3. The first folding rod 6 and the second folding rod 7 are cross-hinged through the folding rod pivot 5, together forming a scissor-type folding rod assembly.

[0029] Furthermore, the upper end of the folding rod assembly is connected to the upper guide rail 8 via a pivot connecting slider 9, and the lower end is connected to the lower guide rail 3 via a lower guide rail bearing 4. The pivot base 10 is fixedly connected to the fuselage load-bearing structure below the wing of the aircraft 1, and is used to support the rotating connection part of the electric actuator cylinder 11. One end of the electric actuator cylinder 11 is hinged to the pivot base 10, and the other end is connected to the pivot connecting slider 9 or the corresponding part of the folding rod assembly via transmission. The electric actuator cylinder 11 is internally equipped with a motor and a self-locking mechanism. The motor provides the extension and retraction driving force, and the self-locking mechanism locks the position of the extension rod after it has been extended to its final position.

[0030] Furthermore, the retractable water skid assemblies are symmetrically arranged on the left and right sides of the aircraft 1, with one set on each side. The two sets of retractable water skid assemblies have the same structure and are independent of each other, and are controlled separately by the coupling control system.

[0031] In one specific embodiment, the body 2 of the water ski is a solid structure made of lightweight and high-strength materials, such as aluminum alloy, titanium alloy or carbon fiber composite material, and its bottom surface has a smooth water skimming surface to provide lift and support when gliding on the water surface.

[0032] It should be noted that the main body 2 of the water ski does not directly contact the water surface during normal flight and landing. Its function is to adjust the lever arm by changing the extension length, thereby generating a roll restoring torque.

[0033] Furthermore, the lower guide rail 3 is arranged along the length of the main body 2 of the water skid plate, and its cross-sectional shape is an I-shaped, T-shaped or rectangular groove. The lower guide rail bearing 4 adopts a ball bearing or a sliding bushing to form a rolling or sliding fit with the lower guide rail 3.

[0034] Furthermore, the first folding rod 6 and the second folding rod 7 are made of high-strength steel or aluminum alloy, and have a rectangular or circular cross-section. They are hinged at the intersection point by the folding rod pivot 5, and the folding rod pivot 5 is provided with a bushing or rolling bearing to reduce rotational friction.

[0035] Based on the above embodiments, the electric actuator 11 is further designed as an electric cylinder, with its internal motor being a servo motor or a stepper motor. The rotational motion of the motor is converted into the linear motion of the telescopic rod through a lead screw and nut pair.

[0036] Furthermore, the self-locking mechanism can adopt worm gear self-locking, electromagnetic brake or mechanical wedge locking method. When the electric actuator 11 moves to the position and the motor stops supplying power, the self-locking mechanism can maintain the current position of the telescopic rod and prevent uncommanded displacement under aerodynamic load, hydrodynamic load or vibration impact.

[0037] Furthermore, the telescopic end of the electric actuator 11 is hinged to the rotating shaft connecting slider 9 via a pin. When the electric actuator 11 extends, its telescopic end pushes the rotating shaft connecting slider 9 to move along the upper guide rail 8 in the unfolding direction; when the electric actuator 11 retracts, its telescopic end pulls the rotating shaft connecting slider 9 to move along the upper guide rail 8 in the retracting direction. By driving the folding rod assembly to retract and extend through the electric actuator 11, the water skid body 2 can be retracted and drag reduced during the flight phase and extended to bear load during the landing phase.

[0038] like Figure 2 As shown, during the takeoff and high-altitude flight phases of aircraft 1, the retractable water skid assembly is in a retracted state. At this time, the electric actuator 11 remains in the retracted position, its internal self-locking mechanism is engaged, and the slider 9 connected to the telescopic end traction shaft is located at the retracted end of the upper guide rail 8. The first folding rod 6 and the second folding rod 7 move closer together around the folding rod shaft 5, minimizing the overall height of the folding rod assembly. The lower guide rail bearing 4 moves along the lower guide rail 3 to the retracted position, causing the water skid body 2 to rise and approach the underside of the fuselage or wing of aircraft 1. In this retracted state, the water skid body 2 is stably concealed within the low-drag envelope of aircraft 1, not protruding beyond the projected outline of the fuselage and wing, thereby effectively reducing additional drag during high-altitude flight.

[0039] like Figure 3 and Figure 4As shown, when aircraft 1 transitions from high-altitude flight to sea-skimming flight, sea-landing preparation, or emergency landing, the coupling control system determines whether the conditions for the water skid extension are met based on flight altitude, flight speed, attitude angle, and landing command. Once the extension conditions are met, the coupling control system sends an extension command to the electric actuator 11. The motor of the electric actuator 11 first releases the self-locking state of the retracted position, then drives the lead screw nut pair to actuate, causing the telescopic rod to gradually extend outward from the retracted position. The extended end of the telescopic rod pushes the rotating shaft connecting slider 9 to move along the upper guide rail 8 in the unfolding direction. Since the first folding rod 6 and the second folding rod 7 are cross-hinged through the folding rod rotating shaft 5, when the rotating shaft connecting slider 9 moves along the upper guide rail 8, the first folding rod 6 and the second folding rod 7 are forced to rotate relative to each other around the folding rod rotating shaft 5, and the included angle between them gradually increases, causing the entire folding rod assembly to unfold downwards. After the folding rod assembly is unfolded, its lower end acts on the lower guide rail 3 through the lower guide rail bearing 4. The lower guide rail bearing 4 rolls or slides along the lower guide rail 3, converting the unfolding motion of the folding rod assembly into the vertical extension displacement of the water skid body 2 relative to the aircraft 1. When the position sensor 12 detects that the stroke of the electric actuator 11, the position of the rotating shaft connecting slider 9, or the unfolding angle of the folding rod assembly reaches the preset extension position, the coupling control system stops supplying power to the electric actuator 11 and relocks the self-locking mechanism, fixing the water skid body 2 at the working height position.

[0040] It should be understood that, in practical applications, the extension amount of the water skid body 2 can be adjusted in stages or continuously according to the landing weight of the aircraft 1, sea conditions, and descent rate. The coupling control system stores a target extension amount comparison table or calculation model for different operating conditions. By acquiring flight parameters and sea state parameters in real time, the extension amount of the water skid body 2 is dynamically adjusted to obtain the best water contact cushioning effect and water surface gliding stability.

[0041] In this embodiment, the core function of the water skid body 2 is to provide a roll stabilizing torque, rather than directly contacting the water surface for gliding. When the aircraft is subjected to unidirectional disturbances such as unilateral wave impact, crosswind coupling, or wave lift, the water skid body 2 changes the lever arm length between itself and the aircraft's center of gravity through differential extension and retraction, thereby generating a roll restoring torque opposite to the direction of the disturbance. Specifically, when the left side of the aircraft lifts up, the control system controls the left water skid body 2 to extend further downward, moving it further away from the center of gravity and increasing the hydrodynamic damping and support force on the left side; at the same time, it controls the right water skid body 2 to retract appropriately, reducing the lever arm on the right side, thereby generating a roll restoring torque to help the aircraft regain its horizontal attitude.

[0042] like Figure 3As shown, after the main body 2 of the water skid extends, the upper guide rail 8, the pivot connecting slider 9, the first folding rod 6, the second folding rod 7, the folding rod pivot 5, the lower guide rail bearing 4, and the lower guide rail 3 together form a load-bearing transmission chain. When the water touches the sea surface, the water surface load first acts on the bottom surface of the main body 2 of the water skid, and then is transmitted to the lower guide rail bearing 4 via the lower guide rail 3. From there, it is transmitted to the first folding rod 6, the second folding rod 7, and the folding rod pivot 5, and finally to the load-bearing structure of the aircraft 1 via the pivot connecting slider 9, the upper guide rail 8, and the pivot base 10. Wear-resistant bushings or rolling bearings are provided at each hinge point and sliding mating surface in this load-bearing transmission chain to reduce friction loss and stress concentration during transmission.

[0043] In one specific embodiment, the retractable water ski assembly also includes a position sensor 12 and a load sensor 13.

[0044] Specifically, the position sensor 12 is located near the upper guide rail 8, the electric actuator 11, or the folding rod assembly to detect the telescopic displacement of the water skid body 2, the stroke of the electric actuator 11, or the unfolding angle of the folding rod assembly.

[0045] Based on the above embodiments, the position sensor 12 can be a linear variable differential transformer, a magnetostrictive displacement sensor, a Hall effect position sensor, or a photoelectric encoder.

[0046] Specifically, the load sensor 13 is installed on the water skid body 2, the lower guide rail 3, the folding rod assembly or their connecting parts, and is used to detect the water load, impact load or load difference between the left and right water skids borne by the water skid body 2.

[0047] Based on the above embodiments, the load sensor 13 can be a strain gauge force sensor, a piezoelectric force sensor, or a fiber optic pressure sensor.

[0048] Through real-time detection by position sensor 12 and load sensor 13, the coupling control system can simultaneously obtain the current extension position of the retractable water ski assembly and the magnitude and distribution of the water surface contact load, thereby determining whether the water ski body 2 has been fully extended, whether a sudden change in unilateral load has occurred, and whether further adjustment of the extension amount is needed.

[0049] In this embodiment, as Figure 6 As shown, the air cushion-assisted landing assembly includes an air cushion body 16, an inflation source 17, an air vent 18, and a pressurization chamber 19.

[0050] In one specific embodiment, the air cushion 16 is made of a flexible, airtight material, such as rubber-coated fabric, polyurethane-coated fabric, or aramid-reinforced composite material, and is elongated or rectangular in shape, arranged longitudinally or laterally under the belly of the aircraft 1.

[0051] Based on the above embodiments, the air cushion 16 is attached to or stored on the belly surface of the aircraft 1 in an uninflated state, without interfering with the aerodynamic shape of the aircraft.

[0052] Based on the above embodiments, the inflation source 17 adopts a high-pressure gas cylinder, an electric compressor, or a gunpowder gas generator to provide high-pressure gas to the air cushion 16 when needed.

[0053] Based on the above embodiments, the pressurization chamber 19 is disposed on the gas pipeline between the inflation source 17 and the air cushion 16, serving as a gas distribution and pressure buffer chamber. It is used to establish a predetermined pressure before the air cushion 16 is deployed, and to temporarily store, stabilize and distribute the high-pressure gas output from the inflation source 17.

[0054] Based on the above embodiments, the volume and structure of the pressurization chamber 19 are further determined according to the volume of the air cushion 16 and the required inflation rate. A throttling orifice plate or a pressure regulating valve can be installed inside it to control the gas flow rate and pressure rise rate entering the air cushion 16.

[0055] Furthermore, vents 18 are disposed on the surface of the air cushion 16 and distributed along the length and width directions of the air cushion 16. The pore size, number, and distribution density of the vents 18 are determined according to the working pressure and expected depressurization rate of the air cushion 16. The vents 18 are connected to the outside atmosphere, and their function is not to introduce air into the air cushion 16, but to allow the gas inside the bladder to be discharged outward in a controlled manner after the air cushion 16 is inflated and deployed, so as to form an air film buffer zone under the bladder at the moment of water contact, smoothing the load transfer, and regulating the internal pressure of the air cushion 16 by active venting or passive depressurization when the water contact load changes.

[0056] During sea landing or emergency landing, the air cushion landing aid assembly and the retractable water skid assembly work together. The inflation source 17 supplies air to the pressurization chamber 19, which first establishes a predetermined pressure before introducing the gas into the air cushion bladder 16. Under the influence of the gas, the air cushion bladder 16 gradually inflates and expands, changing from an attached state to an inflated state, protruding below the fuselage of the aircraft 1. Upon impact with the water, the air cushion bladder 16 first undergoes elastic deformation, absorbing a portion of the vertical impact energy. Subsequently, the gas inside the bladder is discharged in a controlled manner through the air vents 18, forming an air film buffer zone between the air cushion bladder 16 and the sea surface. This air film buffer zone can convert the instantaneous impact load into a relatively gentle pressure load, effectively reducing the peak overload transmitted to the aircraft 1, and together with the water skid bodies 2 on both sides, constitutes a water surface support structure.

[0057] Based on the above embodiments, the inflation pressure of the air cushion 16 can be further adjusted according to the descent rate, landing weight, and sea conditions of the aircraft 1. When the vertical descent speed is high or the expected impact on the water is strong, the inflation source 17 increases the air supply to the pressurization chamber 19, so that the air cushion 16 has a high initial support pressure before contact with the water; when the internal pressure of the air cushion 16 exceeds a predetermined threshold after contact with the water, the excess gas is quickly discharged through the air vent 18 to prevent the impact load from being directly transmitted to the aircraft body. Through the continuous adjustment of air supply, pressure stabilization, exhaust, and pressure relief, the air cushion 16 provides auxiliary vertical buffering for the water skid plate body 2 and effectively suppresses the sudden change in attitude of the aircraft 1 at the moment of contact with the sea surface.

[0058] Under unidirectional disturbance conditions, such as when aircraft 1 encounters wave height on one side during sea-skimming flight or landing, the main body 2 of the left-side water skid plate is lifted by the impact of the waves or subjected to a sudden increase in load. At this time, aircraft 1 will produce the following: Figure 7 The sudden roll trend is shown. The coupling control system first identifies the load difference between the left and right water skid bodies 2 through the load sensor 13, and combines the roll angle and roll angular velocity information of the aircraft 1 to comprehensively determine the direction and amplitude of the roll disturbance.

[0059] Subsequently, to suppress the roll disturbance, the coupling control system employs a stabilization control strategy primarily based on the differential extension and retraction of the water skids. The core of this strategy lies in controlling the water skid body 2 on the disturbed side to extend further. Specifically, when the left side of the aircraft 1 is lifted due to the surge impact, the coupling control system sends a further extension command to the left-side electric actuator 11, driving the left-side folding rod assembly to continue unfolding, causing the left-side water skid body 2 to extend further downwards. At this time, the horizontal distance (i.e., lever arm) of the left-side water skid body 2 relative to the center of gravity (or center of mass) of the aircraft 1 increases significantly, thereby generating a larger roll recovery torque than the right side under the hydrodynamic action of the left side. This torque is in the opposite direction to the disturbance, effectively resisting the roll tendency and restoring the aircraft to the expected attitude. Simultaneously, the coupling control system can cooperate with the control of the right-side electric actuator 11 to make adaptive adjustments, such as maintaining or slightly shortening it, to collaboratively generate the recovery torque.

[0060] During this process, the coupling control system can also coordinate the differential deflection of the left and right ailerons 15, for example, deflecting the left aileron 15 upward and the right aileron 15 downward, to generate an auxiliary aerodynamic restoring torque. However, when close to the water surface and the skid plate is in contact with the water, the mechanical stabilization method of actively extending one side of the skid plate to increase the restoring arm has the advantages of direct response and significant effect.

[0061] Through the above-mentioned coordinated control, in the pre-touch phase, attitude pre-adjustment is mainly achieved by aileron deflection and pre-extension of the water skids; at the moment of touchdown, shock absorption and attitude maintenance are mainly achieved by differential control of air cushion cushioning and active extension of the single-sided water skids; in the post-touch glide phase, attitude stabilization is continued by differential extension and retraction of the water skids and aileron deflection, thereby effectively suppressing roll instability caused by unilateral disturbances throughout the entire landing process.

[0062] It is particularly important to emphasize that the differential extension and retraction of the main body 2 of the water skid is the key difference between this embodiment and the prior art. Traditional fixed water skids cannot dynamically adjust the lever arm according to disturbances, while this solution, by actively controlling the extension of the water skid, can make the water skid on the disturbed side farther from the center of gravity when a disturbance occurs on one side, thereby generating a larger roll recovery torque and significantly improving the roll stability of the aircraft during water landing.

[0063] Based on the above embodiments, the folding rod group in the retractable water ski assembly can further adopt a multi-stage scissor structure, that is, it is composed of three or four sets of cross linkages connected in series, so as to obtain a larger extension ratio and a more compact storage volume.

[0064] Furthermore, the number of electric actuators 11 can be one or more sets. When multiple sets of electric actuators are used, each electric actuator operates synchronously to ensure the uniformity of the unfolding and retraction of the folding rod assembly.

[0065] Furthermore, the bottom surface of the water skid body 2 can be provided with drag-reducing stripes or guide grooves to reduce resistance when gliding on the water surface and improve directional stability.

[0066] Furthermore, the outer surface of the air cushion body 16 may be provided with an abrasion-resistant layer or a puncture-resistant layer to improve durability and reliability under complex sea conditions.

[0067] This invention also provides a stabilization control method for an aircraft water landing system. Based on the above-described aircraft water landing system, the method includes the following steps: In step S1, when the aircraft 1 takes off from the safe altitude takeoff platform 14 and enters the high-altitude flight stage, the coupling control system controls the electric actuator 11 to shorten to the retracted position and activates self-locking, so that the folding rod group is retracted and the water skid body 2 is hidden under the belly or wing of the aircraft 1 and is in a retracted state.

[0068] In step S2, when the aircraft 1 enters the sea-skimming flight or sea-landing preparation stage, the coupling control system determines that the conditions for extending the water skid plate are met based on the flight altitude, flight speed, attitude angle, and landing command, and then issues an extension command to the electric actuator 11. The electric actuator 11 releases its self-lock and extends, driving the rotating shaft connecting slider 9 to move along the upper guide rail 8, causing the first folding rod 6 and the second folding rod 7 to rotate and unfold around the folding rod rotating shaft 5, so that the water skid plate body 2 extends downward to the working height. Subsequently, the electric actuator 11 relocks itself, maintaining the extended position of the water skid plate body 2.

[0069] In step S3, when the aircraft 1 enters the sea surface landing or emergency landing phase, the inflation source 17 supplies air to the pressurization chamber 19. After the pressurization chamber 19 establishes a predetermined pressure, the gas is introduced into the air cushion 16, causing the air cushion 16 to inflate and deploy. The air holes 18 on the surface of the air cushion 16 expel air outward at the moment of contact with water, forming an air film buffer zone to smoothly transfer the load.

[0070] Step S4: Before and after water contact, the coupling control system acquires the left and right extension displacement of the water skid plate detected by the position sensor 12, the left and right water contact load detected by the load sensor 13, and the attitude information of the aircraft 1 in real time. Based on the above information, the left and right extension amount of the retractable water skid plate assembly and the deflection amount of the left and right ailerons 15 are coordinated and controlled.

[0071] In step S5, when a disturbance such as a unilateral surge occurs, the coupling control system determines the direction and amplitude of the roll disturbance based on the displacement difference and load difference between the left and right water skids, as well as the roll angle and roll angular velocity of the aircraft 1. If it is determined that the aircraft 1 is tilting to one side (e.g., the left), a further extension command is sent to the electric actuator 11 on that side (left), driving the left water skid body 2 to continue extending downwards, thereby increasing its lever arm relative to the aircraft's center of gravity and generating a larger roll recovery torque on the left to resist the current tilting trend. At the same time, the control system can adjust the extension amount of the other water skid and coordinate the differential deflection of the left and right ailerons 15 to comprehensively suppress the roll instability caused by the unilateral disturbance and maintain the water landing stability of the aircraft 1.

[0072] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0073] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A water landing system for an aircraft, characterized in that, include: The retractable water ski assembly is located below the aircraft (1) and includes a water ski body (2), a folding rod assembly, an upper guide rail (8), a pivot connecting slider (9), and an electric actuator (11). The upper guide rail (8) is fixedly connected to the load-bearing structure of the aircraft (1). The pivot connecting slider (9) is slidably engaged with the upper guide rail (8). One end of the folding rod assembly is connected to the upper guide rail (8) through the pivot connecting slider (9), and the other end of the folding rod assembly is connected to the water ski body (2). The electric actuator (11) is used to drive the folding rod assembly to unfold or retract, so as to drive the water ski body (2) to extend or retract. The air cushion-assisted landing assembly is located under the belly of the aircraft (1) and includes an air cushion body (16) and an inflation source (17), wherein the inflation source (17) is used to inflate the air cushion body (16); A coupling control system is connected to the retractable water ski assembly to control the extension and retraction of the water ski body (2).

2. The aircraft water landing system according to claim 1, characterized in that, The folding rod assembly includes a first folding rod (6), a second folding rod (7), and a folding rod pivot (5). The first folding rod (6) and the second folding rod (7) are cross-hinged through the folding rod pivot (5) to form a scissor-type folding rod assembly.

3. The aircraft water landing system according to claim 2, characterized in that, The retractable water ski assembly also includes a lower guide rail (3) and a lower guide rail bearing (4). The lower guide rail (3) is fixedly installed on the upper surface of the water ski body (2). The lower guide rail bearing (4) slides or rolls with the lower guide rail (3). The other end of the folding rod assembly is connected to the lower guide rail (3) through the lower guide rail bearing (4).

4. The aircraft water landing system according to claim 1, characterized in that, The electric actuator (11) is equipped with a self-locking mechanism, which is used to lock the position of the telescopic rod of the electric actuator (11) after the water skid plate body (2) is extended or retracted into place.

5. The aircraft water landing system according to claim 1, characterized in that, The surface of the air cushion body (16) is provided with air holes (18), which are used to release air outward when the air cushion body (16) touches water, forming an air film buffer zone between the air cushion body (16) and the water surface.

6. The aircraft water landing system according to claim 1 or 5, characterized in that, The air cushion-assisted landing assembly also includes a pressurization chamber (19), which is located on the gas pipeline between the inflation source (17) and the air cushion body (16) and is used to establish a predetermined pressure before the air cushion body (16) is inflated.

7. The aircraft water landing system according to claim 1, 2, or 3, characterized in that, The retractable water skid assembly is symmetrically arranged on the left and right sides of the aircraft (1). The retractable water skid assembly on the left and right sides is independent of each other and is respectively connected to the coupling control system.

8. The aircraft water landing system according to claim 7, characterized in that, The retractable water ski assembly also includes a position sensor (12), which is located on the upper guide rail (8), the electric actuator (11) or the folding rod assembly, and is used to detect the telescopic displacement of the water ski body (2).

9. The aircraft water landing system according to claim 7, characterized in that, The retractable water ski assembly also includes a load sensor (13), which is disposed on the water ski body (2), the folding rod group or its connection part, and is used to detect the water surface load borne by the water ski body (2).

10. A stabilization control method for an aircraft water landing system, based on the aircraft water landing system according to any one of claims 1 to 9, characterized in that, Includes the following steps: During the high-altitude flight phase, the electric actuator (11) is controlled to retract by the coupling control system, so that the folding rod group is retracted and the main body (2) of the water skid is stored under the fuselage of the aircraft (1); During the landing preparation phase, the electric actuator (11) is extended by the coupling control system, driving the rotating shaft connecting slider (9) to move along the upper guide rail (8), which in turn causes the folding rod group to unfold, so that the water skid plate body (2) extends downward to the working height; During the landing and water contact phase, the inflation source (17) inflates the air cushion body (16) to cause the air cushion body (16) to deploy and buffer the impact of water contact. Before and after contact with water, the coupling control system coordinates and controls the extension of the water skid body (2) on the left and right sides according to the attitude information of the aircraft (1) and the load information of the water skid body (2) to suppress roll disturbance.

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