Transverse and longitudinal static stability variable centroid control mechanism

Abstract

The invention discloses a transverse and longitudinal static stability variable centroid control mechanism and relates to the technical field of aircrafts. The invention aims to solve the problems that although an existing variable centroid mechanism can partially replace a pneumatic control surface, the dynamic performance is insufficient, the centroid adjusting range is limited, and a nonlinear centroid track required by rolling, pitching and yawing multi-axis coupling control cannot be met; and a traditional mass block only adopts a counterweight function design, occupies the internal space of the aircraft and is not reused as a functional module such as energy storage, so that the overall energy efficiency ratio of the system is low. The unmanned aerial vehicle comprises wings, push rods, batteries and guide rails, the wings are arranged on the upper side and the lower side of the aircraft body respectively, the guide rail is arranged between the two wings, the push rod and the battery are arranged in the guide rail, and the push rod is used for adjusting the position of the battery. The method is used for adjusting the mass center of the aircraft.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and particularly to a transverse and longitudinal static stability variable center-of-mass control mechanism. Background Art

[0002] The attitude control of traditional statically unstable aircraft mainly relies on aerodynamic control surfaces or thrust vectoring technology, but there are significant defects in the following scenarios: High-altitude thin air environment and low-speed flight scenarios: The aerodynamic efficiency of aerodynamic control surfaces drops sharply due to the decrease in air density, and sufficient control torque cannot be generated, seriously affecting flight stability; Stealth design requirements: The deflection of control surfaces will damage the stealth configuration of the aircraft's shape, increase the radar cross-section, and the mechanical movement of the control surface actuators is prone to generate infrared signature signals; Limitations of thrust vectoring technology: Relying on complex mechanical structures such as vector nozzles to adjust the thrust direction not only increases the system weight and failure rate, but also shortens the component life due to the erosion of high-temperature gas, resulting in high maintenance costs.

[0003] Although existing variable center-of-mass mechanisms can partially replace aerodynamic control surfaces, there are still the following problems: 1 Insufficient dynamic performance: Using a single mass block translation or rotation structure such as linear guideway counterweight and rotating flywheel, the response speed generally exceeds 100 ms, making it difficult to meet the millisecond-level real-time control requirements of high-maneuverability aircraft; 2 Limited center-of-mass adjustment range: The single-degree-of-freedom adjustment mechanism can only achieve a center-of-mass offset of ±5% in the longitudinal axis direction of the fuselage, and cannot meet the non-linear center-of-mass trajectory required for roll, pitch, and yaw multi-axis coupling control; 3 Low space utilization: Traditional mass blocks are only designed for counterweight functions, occupying the internal space of the aircraft without being reused as functional modules such as energy storage, resulting in a low overall energy efficiency ratio of the system.

[0004] For example, the structure and control method of a variable center-of-mass ducted drone in the prior art with the publication number CN118701336. A cross slide rail is arranged in the duct, and four variable center-of-mass actuators are circumferentially and evenly distributed; the actuators slide along the slide rail through gear-rack meshing to change the center of mass of the fuselage; attitude decoupling is achieved by combining PID control. Its structure is redundant: the slide rail and the rack occupy the duct space, reducing the aerodynamic efficiency; low drive efficiency: the friction loss of the gear-rack is large, and the response speed is limited to >80 ms; narrow application scenario: only applicable to low-speed ducted drones and cannot be adapted to high-speed aircraft.

[0005] The prior art with the publication number CN 108146653 B is an efficient trimming method for adapting to the changing center of mass of aircraft with complex shapes. The aircraft is divided into quadrants I - IV, and a geometric coordinate system OXYZ is established; access covers are provided in the equipment compartment and servo compartment, and high - density tungsten - infiltrated copper counterweights are installed; by adjusting the position of the counterweights axially / circumferentially, three - dimensional center - of - mass trimming is achieved while keeping the total mass unchanged. Its manual adjustment takes a long time: the access cover needs to be disassembled and the position of the counterweights adjusted manually, and it cannot respond to the flight state in real time; the adjustment accuracy is low: the interface spacing of the counterweight installation is 20 - 50 mm, and the ability to finely adjust the center of mass is insufficient; the function is single: the counterweights are only dead weights, occupying space and without energy reuse; the expandability is poor: relying on the fixed access cover and stiffener structure, it is difficult to adapt to the requirements of multiple aircraft models. Therefore, a transverse and longitudinal static - stability variable - center - of - mass control mechanism is provided to solve the above problems, a variable - center - of - mass mechanism with high dynamics, multiple degrees of freedom, and function integration, which can quickly and accurately adjust the center of mass of the aircraft within a limited space. Summary of the Invention

[0006] The purpose of the present invention is to provide a variable - center - of - mass mechanism with high dynamics, multiple degrees of freedom, and function integration. Through a lightweight drive layout, it can quickly and accurately adjust the center of mass of the aircraft within a limited space, and at the same time reuse the mass module as the energy unit of the aircraft to solve the technical problems in the background technology.

[0007] The technical solution adopted by the present invention to solve the above problems is: a transverse and longitudinal static - stability variable - center - of - mass control mechanism, including an aircraft body, wings, a push rod, a battery, and a guide rail; wings are respectively arranged on the upper and lower sides of the aircraft body, the guide rail is arranged between the two wings, and a push rod and a battery are arranged inside the guide rail, and the push rod is used to adjust the position of the battery.

[0008] Furthermore, the guide rail includes two guide - rail components, and each guide - rail component is composed of two mutually - connected guide - rail monomers; a push rod and a battery are arranged inside each guide - rail monomer, and the four guide - rail monomers are arranged symmetrically in a rhombus shape.

[0009] Furthermore, one end of the two guide - rail monomers in the guide - rail component is connected by an intermediate adapter block, and the other end is connected to a connection block.

[0010] Furthermore, a track is arranged inside the guide - rail monomer, and the push rod and the battery are installed inside the track.

[0011] Furthermore, one end of the push rod is connected to the connection block, and the other end is connected to the battery.

[0012] Furthermore, the included angle α between two adjacent guide - rail monomers in the two guide - rail components is 15° - 40°.

[0013] Furthermore, the included angle β between the two guide - rail monomers in the guide - rail component is 100° - 140°.

[0014] Further, the connecting block is connected to the aircraft body.

[0015] Further, a fuselage frame is provided between the two wings, and the fuselage frame is connected to the aircraft body.

[0016] Further, the push rod is an electric push rod, and the battery is a high energy density solid-state battery.

[0017] The present invention has the following beneficial technical effects:

[0018] 1. In the present invention, the diamond-shaped guide rails installed on the aircraft body are arranged between the two wings. The inside of the guide rails is provided with a push rod and a battery, and the push rod is used to adjust the position of the battery. The present invention uses four high energy density batteries symmetrically distributed in a diamond shape, which combines the functions of weight balancing and power supply and eliminates dead weight. The layout of the diamond vertices maximizes the lateral / longitudinal adjustment moment arm.

[0019] 2. The present invention uses electric push rods for collaborative driving. The high-precision ball screw electric push rods are obliquely installed, and three-axis centroid adjustment is achieved through four-degree-of-freedom linkage. The base of the push rod is connected to the fuselage frame through a flexible hinge to compensate for the installation error caused by the structural deformation of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the present invention;

[0021] Figure 2 is an axonometric view of the present invention;

[0022] Figure 3 is a schematic structural diagram of the guide rail of the present invention;

[0023] Figure 4 is Figure 3 the front view of;

[0024] Figure 5 is Figure 3 the left view of;

[0025] Figure 6 is a schematic structural diagram of the X-axis and Y-axis of the present invention;

[0026] Figure 7 is a schematic structural diagram of the Y-axis and Z-axis of the present invention;

[0027] In the figure, 1, wing; 2, push rod; 3, battery; 4, guide rail; 41, guide rail unit; 42, track; 43, intermediate adapter block; 44, connecting block; 5, fuselage frame. DETAILED DESCRIPTION OF THE INVENTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings of the specification and embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Specific Embodiment 1: In combination with Figures 1 to 7 This embodiment is described. A transverse and longitudinal statically stable variable center of mass control mechanism, a transverse and longitudinal statically stable variable center of mass control mechanism, includes an aircraft body, a wing 1, a push rod 2, a battery 3, and a guide rail 4; wings 1 are respectively arranged on the upper and lower sides of the aircraft body, the guide rail 4 is arranged between the two wings 1, a push rod 2 and a battery 3 are arranged inside the guide rail 4, and the push rod 2 is used to adjust the position of the battery 3. The present invention is applicable to statically unstable aircraft.

[0030] In a preferred embodiment, the guide rail 4 includes two guide rail components, and each guide rail component is composed of two guide rail monomers 41 connected to each other; a push rod 2 and a battery 3 are arranged inside each guide rail monomer 41, and the four guide rail monomers 41 are arranged symmetrically in a rhombus shape, and each guide rail monomer 41 serves as a side of the rhombus.

[0031] In a preferred embodiment, one end of the two guide rail monomers 41 in the guide rail component is connected through an intermediate adapter block 43, and the other end is connected to a connection block 44.

[0032] In a preferred embodiment, a track 42 is arranged inside the guide rail monomer 41, and the push rod 2 and the battery 3 are installed inside the track 42.

[0033] In a preferred embodiment, one end of the push rod 2 is connected to the connection block 44, and the other end is connected to the battery 3.

[0034] In a preferred embodiment, the included angle α between two adjacent guide rail monomers 41 of the two guide rail components is 15° - 40°.

[0035] In a preferred embodiment, the included angle α between two adjacent guide rail monomers 41 of the two guide rail components is 15°.

[0036] In a preferred embodiment, the included angle α between two adjacent guide rail monomers 41 of the two guide rail components is 40°.

[0037] In a preferred embodiment, the included angle β between the two guide rail monomers 41 in the guide rail component is 100° - 140°.

[0038] In a preferred embodiment, the included angle β between the two guide rail monomers 41 in the guide rail component is 100°.

[0039] In a preferred embodiment, the included angle β between the two guide rail monomers 41 in the guide rail assembly is 140°.

[0040] In a preferred embodiment, the connecting block 44 is connected to the aircraft body. The connecting block 44 is connected to the fuselage frame of the aircraft body through a flexible hinge.

[0041] In a preferred embodiment, a fuselage frame 5 is further arranged between the two wings 1, and the fuselage frame 5 is connected to the aircraft body.

[0042] In a preferred embodiment, the push rod 2 is an electric push rod, and the battery 3 is a high energy density solid-state battery. Preferably, the base of the push rod 2 is connected to the connecting block 44, and the cylinder rod of the push rod 2 is connected to the battery 3. Or the cylinder rod of the push rod 2 is connected to the connecting block 44, and the base of the push rod 2 is connected to the battery 3. The push rod 2 can also adopt a linear motor, etc.

[0043] Specific Embodiment 2: In combination Figures 1 to 7 Describe this embodiment. In this embodiment, a rhombic battery topology layout is adopted: four high energy density batteries are symmetrically distributed in a rhombus, combining the functions of weight balance and power supply, eliminating dead weight; the layout of the rhombus vertices maximizes the lateral / longitudinal adjustment moment arm.

[0044] In a preferred embodiment, the electric push rods are driven in cooperation: a high-precision ball screw electric push rod (thrust ≥ 500N) is installed obliquely at 45°, and the three-axis centroid adjustment is realized through a four-degree-of-freedom linkage; based on a cooperative control algorithm of a non-linear disturbance observer, the coupling interference of multiple push rods is suppressed.

[0045] In a preferred embodiment, modular expansion design: the battery pack and the electric push rod adopt a standardized interface, supporting quick replacement or additional configuration of modules.

[0046] In the rhombic battery pack layout of this embodiment: four high energy density batteries are distributed in a rhombic topology, combining the functions of weight balance and power supply, eliminating dead weight.

[0047] Multiple electric push rods are driven in cooperation: the electric push rods are rigidly connected to the battery pack, and the three-dimensional dynamic adjustment of the centroid is realized through a four-degree-of-freedom linkage algorithm.

[0048] Redundant fault tolerance design: when any one of the electric push rods fails, the remaining three groups can reconfigure the thrust distribution to ensure the reliability of the system.

[0049] In this embodiment, the application prospects of the present invention: Military field: Pitch / roll control of the sixth-generation stealth fighter and hypersonic missile.

[0050] Civilian field: Wind disturbance resistance and stability of vertical takeoff and landing unmanned aerial vehicles (eVTOL), aerodynamic heat management of space reentry vehicles.

[0051] Derivative applications: It can be extended to the attitude adjustment systems of underwater submersibles and Mars rovers.

[0052] Other components and connection relationships are the same as those in the first specific embodiment.

[0053] Specific embodiment three: Figures 1 to 7 This embodiment will be described in combination with the following figure. In this embodiment, the layout of the variable center of mass mechanism of the present invention in the aircraft is shown in the following figure, which is composed of a wing 1, a push rod 2, a battery 3, and a guide rail 4.

[0054] Rhombic battery pack spatial configuration:

[0055] Installation position: Four high-energy density solid-state batteries (model: Li-Solid 400X) are symmetrically arranged at the vertices of a rhombus and embedded in the low-turbulence area between the upper and lower wing surfaces. Specifically, it is located in front of the firewall at the rear of the cockpit, and is designed to be conformal with the fuselage skin to avoid damaging the aerodynamic stealth characteristics.

[0056] Thermal management design: A microchannel liquid cooling plate is integrated at the bottom of the battery pack, and the coolant (ethylene glycol - aqueous solution) is circulated through the aircraft environmental control system to ensure the working stability of the battery in the environment of -40°C to 80°C.

[0057] Installation topology of the electric push rod:

[0058] Axial direction of the push rod: The included angle between the four groups of electric push rods (model: EPD-500S) and the longitudinal axis of the fuselage is preferably 45°. The base of the push rod is connected to the fuselage frame through a flexible hinge to compensate for the installation error caused by the structural deformation of the aircraft.

[0059] Stroke and coverage range: The stroke of the push rod is ±150mm, and the maximum speed is 300mm / s. It can achieve a displacement of ±120mm, ±85mm, and ±60mm in the X / Y / Z three-axis directions for a single battery position, covering the requirements of center of mass adjustment.

[0060] In a preferred embodiment, the drive unit: The power unit adopts a brushless DC motor + planetary roller screw drive;

[0061] Overload protection: A piezoelectric ceramic force sensor (sampling rate 1kHz) is built in to monitor the load of the push rod in real time. When the impact overload > 20g, mechanical self-locking is triggered to prevent damage to the mechanism.

[0062] Environmental adaptability: The sealing grade of the push rod housing is IP67, and nitrogen is filled inside to inhibit electric arcs. It can operate stably at an altitude of 30km (atmospheric pressure ≤ 1kPa) and a humidity of 100%.

[0063] In a preferred embodiment, energy and signal integration: power supply link: the battery pack is connected to the main power grid of the aircraft through a quick-insert high-voltage interface, supporting bidirectional energy flow (discharge power supply / braking energy recovery);

[0064] Control bus: The push rod controller communicates with the flight control computer through the bus, and the instruction delay ≤ 1ms.

[0065] In a preferred embodiment, the control system and control algorithm for realizing the adjustment of the aircraft's center of mass by controlling the displacement of a single battery in the X / Y / Z axis directions by controlling the push rod stroke adopt the existing technology, and the control logic is as follows:

[0066] 1. Feedforward prediction module

[0067] Disturbance prediction: Input the aircraft angular velocity, acceleration and aerodynamic load distribution data provided by the inertial navigation system, and estimate the center of mass offset trend within the next 50ms through the Kalman filter;

[0068] Based on the non-linear disturbance observer (NDOB), construct an aerodynamic-inertial coupling model, estimate the center of mass offset and convert it into the target displacement commands of four groups of electric push rods, and calculate the telescopic amounts of each push rod through the inverse kinematics model

[0069] 2. Redundant fault tolerance mechanism

[0070] Fault detection and isolation: The push rod is internally equipped with a Hall sensor to monitor the consistency of the motor speed and the lead screw displacement. When the deviation > 5%, it is determined as a fault;

[0071] The faulty push rod is switched to the damping mode (back electromotive force braking), and the remaining three groups of push rods are reconstructed according to the following strategy:

[0072] Degraded control: When a single push rod fails, the system automatically switches to the three-degree-of-freedom control mode, sacrificing the yaw axis adjustment ability (priority: roll > pitch > yaw);

[0073] When two push rods fail, start the emergency trimming program, lock the battery position and activate the backup control of the aerodynamic control surface.

[0074] Other components and connection relationships are the same as those in the first specific embodiment.

[0075] Specific embodiment four: combination Figures 1 to 7 Describe this embodiment. In this embodiment, a variable center of mass mechanism for a statically unstable aircraft includes four high-energy density batteries 1, which are symmetrically arranged in a diamond topology in the middle of the upper and lower wings and behind the cockpit; four groups of electric push rods 2, each group of electric push rods is rigidly connected to a battery, and the included angle between the axial direction of the push rod and the longitudinal axis of the fuselage ranges from 10° to 60°;

[0076] Preferably, there are four sets of electric push rods 2, each set of electric push rods is rigidly connected to a battery, and the included angle between the axial direction of the push rod and the longitudinal axis of the fuselage is 10°; preferably, there are four sets of electric push rods 2, each set of electric push rods is rigidly connected to a battery, and the included angle between the axial direction of the push rod and the longitudinal axis of the fuselage is 15°; preferably, there are four sets of electric push rods 2, each set of electric push rods is rigidly connected to a battery, and the included angle between the axial direction of the push rod and the longitudinal axis of the fuselage is 30°; preferably, there are four sets of electric push rods 2, each set of electric push rods is rigidly connected to a battery, and the included angle between the axial direction of the push rod and the longitudinal axis of the fuselage is 45°; preferably, there are four sets of electric push rods 2, each set of electric push rods is rigidly connected to a battery, and the included angle between the axial direction of the push rod and the longitudinal axis of the fuselage is 60°.

[0077] The control unit, based on the inertial navigation data of the aircraft and the real-time acceleration feedback, drives the telescopic movement of the electric push rod through a cooperative control algorithm to realize the dynamic adjustment of the centroid in three axes.

[0078] In a preferred embodiment, the battery 3 is a solid-state lithium metal battery with an energy density ≥ 400 Wh / kg, and is connected to the aircraft power supply network through a standardized interface, and is reused as a counterweight and energy unit. The battery 3 is a solid-state lithium metal battery, and the included angle range between the axial direction of the solid-state lithium metal battery and the longitudinal axis of the fuselage is 10° - 60°.

[0079] Preferably, the included angle between the axial direction of the solid-state lithium metal battery and the longitudinal axis of the fuselage is 10°; preferably, the included angle between the axial direction of the solid-state lithium metal battery and the longitudinal axis of the fuselage is 15°; preferably, the included angle between the axial direction of the solid-state lithium metal battery and the longitudinal axis of the fuselage is 30°; preferably, the included angle between the axial direction of the solid-state lithium metal battery and the longitudinal axis of the fuselage is 45°; preferably, the included angle between the axial direction of the solid-state lithium metal battery and the longitudinal axis of the fuselage is 60°.

[0080] Other compositions and connection relationships are the same as those in the first specific embodiment.

[0081] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A transverse and longitudinal statically stable variable centroid control mechanism, characterized in that: The variable center of mass mechanism includes an aircraft body, wings (1), push rods (2), batteries (3), and guide rails (4); Wings (1) are respectively arranged on the upper and lower sides of the aircraft body. The guide rail (4) is arranged between the two wings (1). A push rod (2) and a battery (3) are arranged inside the guide rail (4). The push rod (2) is used to adjust the position of the battery (3).

2. The lateral and longitudinal static stability variable centroid control mechanism according to claim 1, characterized in that: The guide rail (4) includes two guide rail assemblies, and each guide rail assembly is composed of two guide rail monomers (41) connected to each other; A push rod (2) and a battery (3) are arranged inside each guide rail monomer (41), and the four guide rail monomers (41) are arranged symmetrically in a rhombus.

3. The lateral and longitudinal statically stable variable centroid control mechanism according to claim 2, wherein: One end of the two guide rail monomers (41) in the guide rail assembly is connected by an intermediate adapter block (43), and the other end is connected to a connection block (44).

4. The lateral and longitudinal static stability variable centroid control mechanism according to claim 3, characterized in that: A track (42) is arranged inside the guide rail monomer (41), and the push rod (2) and the battery (3) are installed inside the track (42).

5. The cross-longitudinal statically stable variable center-of-mass control mechanism according to claim 1, characterized in that: One end of the push rod (2) is connected to the connection block (44), and the other end is connected to the battery (3).

6. The cross-longitudinal statically stable variable center of mass control mechanism according to claim 2, characterized in that: The included angle α between two adjacent guide rail monomers (41) of the two guide rail assemblies is 15° - 40°; 7. The lateral and longitudinal static stability variable centroid control mechanism according to claim 2, wherein: The included angle β between the two guide rail monomers (41) in the guide rail assembly is 100° - 140°.

8. The cross-longitudinal statically stable variable centroid control mechanism according to claim 3, characterized in that: The connection block (44) is connected to the aircraft body.

9. The lateral and longitudinal static stability metamorphic center of mass control mechanism according to claim 1, characterized in that: A fuselage frame (5) is further arranged between the two wings (1), and the fuselage frame (5) is connected to the aircraft body.

10. The cross-longitudinal statically stable variable center of mass control mechanism according to claim 1, characterized in that: The push rod (2) is an electric push rod, and the battery (3) is a high energy density solid-state battery.

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