Aircraft active vibration reduction take-off and landing device, application and take-off and landing method

Abstract

The invention discloses an aircraft active vibration reduction take-off and landing device, application and a take-off and landing method. The aircraft active vibration reduction take-off and landing device comprises a platform mechanism, and a vibration reduction execution system, a sensor system and a control system which are arranged on the platform mechanism; the platform mechanism comprises a vibration reduction platform, and a base is arranged below the vibration reduction platform; the vibration reduction execution system comprises a telescopic structure, a reset hydraulic device and MRC electromagnetic vibration absorbers, the top of the base is connected with the vibration reduction platform through the telescopic structure, and the multiple MRC electromagnetic vibration absorbers are arranged at the top of the base at equal intervals. Efficient impact energy absorption is realized by adopting a hybrid vibration reduction system in which the MRC electromagnetic vibration damper and the telescopic structure are connected in parallel; the MRC electromagnetic shock absorber has a millisecond-level response speed and a wide adjustable damping range, can provide instantaneous high damping at the landing moment, and effectively captures and dissipates impact energy; the two components work cooperatively to form an active and passive combined vibration reduction mechanism with complementary advantages; and the dynamic stress and fatigue damage of the platform structure are obviously reduced, so that the service life of facilities is effectively prolonged.

Description

Technical Field

[0001] This invention relates to the field of vertical takeoff and landing (VTOL) aircraft technology, specifically to an active vibration reduction takeoff and landing device, its application, and a takeoff and landing method. Background Technology

[0002] Electric vertical takeoff and landing (eVTOL) aircraft, as a crucial carrier of future urban air mobility (UAM), require stable, safe, and comfortable takeoff and landing processes. However, most current eVTOL platforms employ rigid structures or simple passive vibration reduction designs, which struggle to meet their operational requirements of high efficiency and low vibration impact. While some existing damping and cushioning solutions have applications in traditional aviation, their direct application to eVTOL platforms still presents significant limitations.

[0003] For example, Chinese utility model patent CN214566136U discloses an "aircraft landing gear with buffer function." This technology uses a triple buffer structure consisting of a first buffer device, a second buffer device, and a buffer block, mainly relying on springs and dampers for passive vibration reduction. Although this design can withstand the huge impact force during aircraft landing to a certain extent, its buffer parameters are fixed and cannot be dynamically adjusted according to the different landing weights, descent speeds, and real-time impact forces experienced by the eVTOL aircraft. When facing eVTOL takeoff and landing scenarios with multiple aircraft types and operating conditions, the vibration reduction effect is unstable and the adaptability is obviously insufficient.

[0004] At the theoretical research and system characteristics level, the article "Simulation Analysis of Damping and Impact Characteristics of Hydraulic Buffers" (authors Fang Yongshou et al., published in *Science, Technology and Engineering*, 2020, No. 19) records that a dynamic impact mathematical model was established for hydraulic buffers, and the Runge-Kutta numerical algorithm was used to programmatically calculate the buffer force under transient impact conditions. While this research deeply analyzes the damping and impact characteristics of hydraulic buffers, it also reveals a fundamental defect of traditional passive hydraulic systems: their damping parameters are essentially fixed after the structure is determined. The article points out that the performance of the buffer largely depends on its preset structural parameters (such as gap width and hydraulic viscosity), and cannot be adaptively adjusted in real time according to changes in external impact loads, thus failing to achieve optimal absorption of impact energy under various impact conditions. Furthermore, the dissertation "Research on Key Technologies of UAV Takeoff and Landing Treadway and Vibration Damping" (Qiu Donghai, 2018) also points out that the design of UAV landing gear buffer systems needs to consider both structural strength and good dynamic quality, while traditional vibration damping elements often have insufficient vibration isolation and anti-interference capabilities when facing complex and variable landing environments. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to solve the instantaneous huge impact on the platform structure when the eVTOL aircraft lands.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] An active vibration reduction takeoff and landing device for aircraft includes a platform mechanism, and a vibration reduction execution system, a sensor system, and a control system mounted on the platform mechanism, wherein the vibration reduction execution system and the sensor system are both connected to the control system. The platform mechanism includes a vibration damping platform, a base is provided below the vibration damping platform, and the vibration damping execution system is supported between the vibration damping platform and the base; The vibration damping system includes a telescopic structure, a reset hydraulic device, and MRC electromagnetic vibration dampers. The four corners of the top of the base are connected to the vibration damping platform through the telescopic structure, and the middle of the top of the base is connected to the vibration damping platform through the reset hydraulic device. Several MRC electromagnetic vibration dampers are equidistantly arranged on the top of the base and outside the reset hydraulic device.

[0008] This application achieves efficient impact energy absorption through a hybrid vibration reduction system employing MRC electromagnetic vibration isolators in parallel with a telescopic structure. The MRC electromagnetic vibration isolators, with their millisecond-level response speed and wide adjustable damping range, can provide instantaneous high damping at landing, effectively capturing and dissipating impact energy. The telescopic structure, on the other hand, assumes static load and initial buffering functions. The two work together to form a complementary active-passive vibration reduction mechanism. This combination significantly reduces the impact force transmitted to the platform foundation, substantially alleviating dynamic stress and fatigue damage to the platform structure, thereby effectively extending the service life of the facility.

[0009] As a further aspect of the present invention: the sensor system includes an acceleration sensor, which is embedded in the back of the vibration damping platform and between the MRC electromagnetic vibration damper and the reset hydraulic device.

[0010] As a further aspect of the present invention, the acceleration sensor is a triaxial acceleration sensor.

[0011] As a further aspect of the present invention, the number of acceleration sensors and MRC electromagnetic dampers is the same.

[0012] As a further aspect of the present invention: the control system includes a controller, which is mounted on the back of the base.

[0013] As a further aspect of the present invention: the MRC electromagnetic vibration damper, the reset hydraulic device, and the acceleration sensor are all connected to the controller.

[0014] As a further aspect of the present invention: the telescopic structure adopts a double helical spring, with one end of the spring connected to the base and the other end connected to the vibration damping platform.

[0015] The present invention also discloses the application of an active vibration damping takeoff and landing device on an eVTOL aircraft.

[0016] This invention also discloses a take-off and landing method for an active vibration reduction take-off and landing device for aircraft, comprising the following four stages: Standby Phase: The telescopic structure is in its naturally extended state, providing basic support; the MRC electromagnetic vibration damper outputs a low standby current, and the magnetorheological fluid maintains a low viscosity and is ready for operation; the reset hydraulic device initiates closed-loop attitude control based on platform displacement deviation. Δ x Output a small amount of liquid pressure to lock the platform in the initial horizontal position. The sensor system continuously monitors and dynamically compensates for minor deviations caused by environmental interference. During the landing impact phase: The sensors detect a sharp increase in the aircraft's acceleration and immediately trigger an impact response; the telescopic structure absorbs 60% to 70% of the initial impact energy; the controller outputs a high current instantaneously through an algorithm, and the MRC switches to a high-damping state in milliseconds, working in conjunction with the telescopic structure to dissipate the remaining impact kinetic energy and smoothly reduce the eVTOL vertical velocity to zero; the hydraulic device does not actively work and passively follows the impact process to avoid interfering with the vibration reduction effect; During the stable mooring phase: the telescopic structure continuously bears the eVTOL static load, preventing the MRC from bearing static loads for extended periods; sensors monitor rotor vibration in real time, and the controller adjusts the MRC current to a low to medium dynamic current, actively counteracting specific frequency vibrations by adjusting the MRC damping force; the hydraulic system continuously monitors levelness, and if uneven load distribution causes... Output compensation fluid pressure to calibrate attitude; Platform reset phase: When the sensor detects the platform's vertical acceleration ,and The controller activates the hydraulic device; the hydraulic device outputs precise hydraulic pressure to drive the MRC and telescopic structure to reset; the MRC outputs low current to reduce reset resistance; after the reset is completed, the system switches to standby mode.

[0017] As a further aspect of the present invention: the control model of the MRC electromagnetic vibration damper is as follows: the damping force model of the MRC electromagnetic vibration damper is derived based on the constitutive properties of the magnetorheological fluid Bingham, as detailed below: The damping force of a single MRC is composed of the superposition of viscous damping force and Coulomb damping force: (1) In equation (1), The dynamic viscosity of the magnetorheological fluid is... A This represents the effective working area of ​​the MRC piston.L The length of the magnetorheological fluid channel. d For channel gap, For the platform's vertical speed, The yield stress of the magnetorheological fluid; Among them, the yield stress of magnetorheological fluid With control current They are linearly correlated and satisfy: (2) In equation (2), The zero-field yield stress of the magnetorheological fluid. This is the yield stress-current proportionality coefficient of the magnetorheological fluid. To control the current; Since the four MRCs are arranged in parallel, the total damping force is four times the damping force of a single MRC. Substituting into equation (2), we get the total MRC damping force: (3) Equation (3) shows that by adjusting the control current It can change the Coulomb damping force component in real time, achieving millisecond-level stepless adjustment of the damping force to adapt to different impact intensities and load requirements.

[0018] As a further aspect of the present invention: the double helical spring bears the static load of the eVTOL and provides initial impact cushioning; its elastic force follows Hooke's Law; and the total elastic force of the four sets of double helical springs connected in parallel is: (4) In equation (4), For a single spring, This is the spring compression displacement (i.e., the vertical displacement of the platform). The control model for the reset hydraulic device is as follows: based on closed-loop control of displacement deviation, the output hydraulic pressure is determined. The total hydraulic pressure consists of elastic force and damping force, satisfying the following conditions: (5) In equation (5), For displacement deviation ( (Initial horizontal position) This is the stiffness coefficient of the hydraulic system. The damping coefficient of the hydraulic system; This is the rate of change of displacement deviation (i.e., deviation velocity). To address potential tilting conditions of the platform, a branch control strategy is adopted, with the hydraulic pressures at the four support points as follows: (6) In equation (6), For the first Displacement deviation of each support point.

[0019] As a further aspect of the present invention: the active and passive coordinated damping total force model formed by the double helical spring and the MRC electromagnetic damper: The MRC and double helical springs are arranged in parallel, with each component having the same displacement and velocity. The total synergistic damping force is the algebraic sum of the elastic force and the MRC damping force. (7) Substituting equations (3) and (4) into equation (7), we get: (8).

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. This application achieves efficient impact energy absorption by employing a hybrid vibration damping system combining MRC electromagnetic vibration dampers and double helical springs in parallel. The MRC electromagnetic vibration dampers possess millisecond-level response speed and a wide adjustable damping range, providing instantaneous high damping at landing to effectively capture and dissipate impact energy. The double helical springs, on the other hand, provide static load and initial buffering. The two work together to form a complementary active-passive vibration damping mechanism. This combination significantly reduces the impact force transmitted to the platform foundation, substantially alleviating dynamic stress and fatigue damage to the platform structure, thereby effectively extending the service life of the facility. 2. In terms of vibration isolation, this invention achieves excellent vibration suppression through a closed-loop feedback system constructed by an accelerometer, controller, and MRC electromagnetic vibration damper. The system can monitor the platform's vibration status in real time and actively apply a counterforce to vibrations of specific frequencies to achieve vibration cancellation. The vibration isolation effect of this active control strategy far exceeds that of passive vibration reduction systems, providing a more stable platform for parked eVTOL aircraft. This not only improves the comfort of passengers boarding and disembarking but also effectively protects the precision equipment on board and reduces the negative impact of vibration on platform facilities. 3. The intelligent adaptive characteristics of this application give it excellent adaptability to different operating conditions; the core algorithm of the control system can analyze vibration characteristics in real time based on sensor data and flexibly adjust the control strategy. This intelligent system achieves adaptive adjustment to different aircraft types, landing weights and attitudes through a complete closed loop of perception, decision-making and execution, enabling a single hardware platform to be compatible with a variety of eVTOL aircraft, greatly improving the versatility and economy of the take-off and landing platform, and perfectly adapting to the diverse needs of the future urban air traffic ecosystem; 4. This invention also features high reliability and stability; the "well" shaped keel structure provides a robust load-bearing base for the platform, and the return hydraulic device ensures continuous attitude recovery capability; even if the active control system experiences a temporary failure, the double helical spring and the platform structure itself can still provide reliable passive vibration reduction and support functions. This redundant safety design ensures the stable operation of the entire system under various working conditions, providing a solid safety guarantee for eVTOL take-off and landing operations. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the active vibration damping take-off and landing device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the back structure of the active vibration damping take-off and landing device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the upper structure of the active vibration damping take-off and landing device according to an embodiment of the present invention; Figure 4 This is a bottom-view cross-sectional structural diagram of the active vibration damping take-off and landing device according to an embodiment of the present invention; Explanation of reference numerals in the attached figures: 1. Vibration damping platform; 2. Frame; 3. Telescopic structure; 4. MRC electromagnetic vibration damper; 5. Reset hydraulic device; 6. Accelerometer; 7. Controller; 8. Base. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0023] Reference Figure 1 An active vibration damping takeoff and landing device for eVTOL aircraft includes a vibration damping platform 1, a frame 2, a telescopic structure 3, an MRC electromagnetic vibration damper 4, a reset hydraulic device 5, an acceleration sensor 6, a controller 7, and a base 8. This device uses the acceleration sensor 6 to detect the impact and vibration generated during eVTOL landing and parking in real time. The controller 7 makes instantaneous decisions and drives the MRC electromagnetic vibration damper 4 to respond precisely, thereby achieving efficient energy absorption, vibration isolation, and automatic attitude recovery. The telescopic structure 3, the MRC electromagnetic vibration damper 4, and the reset hydraulic device 5 work together to physically achieve buffering, energy absorption, and reset functions, forming a hybrid vibration damping system.

[0024] Reference Figure 1 and Figure 2The base 8 is located at the bottom, and the vibration damping platform 1 is arranged parallel above the base 8. The four corners of the top of the base 8 are connected to the vibration damping platform 1 through the telescopic structure 3. At the same time, the base 8 is also connected to the vibration damping platform 1 through the reset hydraulic device 5 at the middle position of the top of the base 8. Four sets of MRC electromagnetic vibration dampers 4 are provided on the top of the base 8 and outside the reset hydraulic device 5. The tops of the four sets of MRC electromagnetic vibration dampers 4 are connected to the vibration damping platform 1. An acceleration sensor 6 is also installed at the bottom of the vibration damping platform 1 and between the MRC electromagnetic vibration dampers 4 and the reset hydraulic device 5. A controller 7 is embedded in the bottom of the base 8.

[0025] Reference Figure 1 and Figure 3 The vibration damping platform 1 is the load-bearing foundation of the entire system. A layer of rubber vibration damping pad is also laid on the top of the vibration damping platform 1 as the interface that directly contacts the eVTOL landing gear. The rubber vibration damping pad can provide initial cushioning and friction for the eVTOL landing gear.

[0026] Reference Figure 1 The keel frame 2 has a "well" shaped structure and is installed on the back of the vibration damping platform 1. This structure is composed of crisscrossing high-strength reinforced beams. Its core function is to quickly and evenly distribute the huge local impact force generated when the eVTOL lands to the entire platform plane and effectively transfer it to the MRC electromagnetic vibration dampers 4 arranged around it, laying a solid mechanical foundation for subsequent active vibration damping.

[0027] Reference Figure 1 and Figure 2 The telescopic structure 3 can adopt a double-bolt spring structure, with four double-bolt spring structures arranged at the four main support points on the periphery of the platform. The telescopic structure 3 mainly bears the static load of the aircraft and passively absorbs most of the impact energy as the first line of defense through its own elastic deformation at the moment of landing.

[0028] Reference Figure 1 , Figure 2 and Figure 4 Four MRC (magnetorheological fluid) electromagnetic vibration dampers 4 are equidistantly installed on the back of the vibration damping platform 1. The dampers are filled with magnetorheological fluid, whose viscosity can change significantly with the change of external magnetic field within milliseconds. When the controller applies a controllable current to the electromagnetic vibration damper coil, its damping force can be adjusted in real time, steplessly and precisely, thereby realizing the instantaneous switching between "soft" isolation and "hard" impact of eVTOL, and actively handling dynamic impact and high-frequency vibration.

[0029] Reference Figure 1 , Figure 2 and Figure 4The reset hydraulic device 5 can be a hydraulic cylinder, which is located at the center of the back of the vibration damping platform 1. Its core function is to be triggered by the controller 7 after the landing impact and when the aircraft leaves the field, output precise hydraulic pressure, drive the piston rod of the compressed telescopic structure 3 and the MRC electromagnetic vibration damper 4 to return to the predetermined initial position, thereby ensuring that the entire take-off and landing platform is accurately restored to a horizontal state and ready for the next take-off and landing.

[0030] Reference Figure 1 and Figure 4 The acceleration sensor 6 is a high-precision triaxial acceleration sensor. There are four acceleration sensors 6. The four acceleration sensors 6 are embedded on the back of the vibration damping platform 1 and between the MRC electromagnetic vibration damper 4 and the reset hydraulic device 5. They are used to continuously and in real time collect the vibration acceleration data of the vibration damping platform 1 in three-dimensional space, and provide decision-making basis for the control system.

[0031] Reference Figure 4 The controller 7 is embedded and fixed on the back of the base 8. As the "brain" of the system, the controller 7 continuously receives real-time data from all acceleration sensors 6; it integrates control algorithms. The system processes the data instantaneously, identifies the current impact intensity and vibration mode, and immediately calculates the optimal damping force required for each MRC electromagnetic damper 4, then outputs the corresponding control current signal.

[0032] The complete workflow for this application consists of the following three stages: Landing Impact Phase: Upon contact with the vibration damping platform 1, the eVTOL aircraft experiences a massive downward impact. Accelerometer 6 immediately detects the rapid change in the eVTOL aircraft's acceleration, and controller 7 responds within milliseconds, sending commands to all four MRC electromagnetic dampers 4 to instantly switch them to "high-damping" mode. At this point, the MRC electromagnetic dampers 4, in conjunction with the parallel telescopic structure 3, efficiently absorb and dissipate the impact kinetic energy, smoothly reducing the eVTOL's vertical velocity to zero, significantly suppressing platform oscillations and structural impact.

[0033] Stable Parking Phase: Once the main impact has passed, the eVTOL aircraft enters the stable parking or startup phase, during which its rotor will generate continuous vibration. Accelerometer 6 continuously monitors these vibrations, while controller 7 dynamically adjusts the damping force of the MRC electromagnetic damper 4 to an optimized "medium-low damping" state. In this state, the system effectively isolates and filters out vibrations transmitted to the platform with a more "soft" posture, providing a relatively stable parking environment for the aircraft.

[0034] Platform reset phase: After the aircraft is confirmed to be stable, controller 7 activates the reset hydraulic device 5 located at the center of the platform. This device outputs precise hydraulic pressure to smoothly and accurately lift the entire platform back to its initial horizontal position.

[0035] In addition, this application has adaptive capabilities; the controller 7 can continuously optimize its control parameter library based on pre-stored parameters of different eVTOL aircraft models (such as weight and landing gear layout) or by analyzing historical landing data through machine learning algorithms, thereby achieving personalized and intelligent vibration reduction for different landing conditions and improving the versatility and economy of the system.

[0036] This application presents an eVTOL takeoff and landing platform with active sensing and intelligent response capabilities. Specifically, it can monitor landing impact and vibration in real time via an accelerometer 6 and dynamically adjust damping force or stiffness through controllable actuators (such as magnetorheological fluid and servo hydraulic systems). This enables precise and adaptive vibration reduction control for different aircraft types, landing weights, attitudes, and environmental disturbances. This active vibration reduction platform effectively addresses three core issues: excessive impact force, vibration transmission, and poor system adaptability, providing critical infrastructure support for the safety, economy, and comfort of eVTOL operations.

[0037] The control principle of this invention is based on a closed-loop architecture of "perception-decision-execution," with "active and passive coordinated vibration reduction + fuzzy PID composite control + hydraulic attitude calibration + adaptive learning optimization" as its core. By accurately sensing the load and vibration state throughout the entire eVTOL takeoff and landing process, it dynamically adjusts the damping force of the MRC electromagnetic vibration damper 4, coordinates with the passive buffering of the double helical spring, and the attitude reset of the hydraulic reset device 5, achieving efficient vibration reduction and attitude stability control under different loads and operating conditions. The following details the process from six dimensions: overall control architecture, core perception and variable definition, key component control model, composite control algorithm, multi-condition collaborative logic, and adaptive optimization. 1. Overall Control Architecture The control system of this invention is a hierarchical closed-loop structure, divided into a perception layer, a decision layer, and an execution layer from top to bottom. Each layer works together to achieve the control objective of "real-time response - precise control - stable output". The perception layer consists of four high-precision triaxial accelerometers 6, which are embedded in key positions of the platform to collect core dynamic parameters such as vertical displacement, vertical velocity, and vertical acceleration of the vibration reduction platform 1 in real time, providing continuous and reliable input data for the decision-making layer. Decision layer: With intelligent controller 7 as the core, it integrates PID deviation correction algorithm, fuzzy parameter correction algorithm and adaptive learning algorithm to process the data of the perception layer in real time, identify the load level, impact intensity and working condition type, and output MRC control current command and hydraulic device drive signal. The execution layer includes MRC electromagnetic vibration dampers 4 (four sets in parallel), double helical springs (four sets in parallel), and a center reset hydraulic device 5. The MRC and double helical springs constitute an active-passive coordinated vibration damping execution unit, and the hydraulic device constitutes an attitude calibration execution unit. It completes damping adjustment, shock absorption, and attitude reset actions according to the instructions of the decision layer.

[0038] 2. Definition of Core Perception and Input Quantity The input to the control system is based on sensor data and preset parameters, with the core definition as follows: Real-time sensing quantity: Platform vertical acceleration (Data collected directly from sensors, unit: m / s²) Vertical displacement of the platform (Calculated by acceleration integral, unit: m) Vertical velocity of the platform (First derivative of displacement, unit: m / s); Preset control parameters: Acceleration setting threshold (Different working conditions are set, landing impact phase is taken) During the stable berthing phase , acceleration due to gravity ), displacement threshold (Hydraulic reset trigger threshold, take) MRC structural parameters (effective working area of ​​piston) Magnetorheological fluid channel length Channel gap (etc.), stiffness coefficient of double helical springs Hydraulic system stiffness coefficient With damping coefficient ; Operating condition identification: Load rating (Based on peak acceleration and pre-stored model parameters, it is divided into light load) 、 medium load Heavy load Impact strength (Based on acceleration amplitude classification, low impact) Impact High impact ).

[0039] 3. Control Model for Key Components 3.1 MRC Electromagnetic Vibration Damper Control Model The core control objective of the MRC electromagnetic vibration damper 4 is to adjust the control current. The damping force is dynamically adjusted by changing the viscosity of the magnetorheological fluid. The damping force model is derived based on the Bingham constitutive properties of the magnetorheological fluid, as detailed below: The damping force of a single MRC is composed of the superposition of viscous damping force and Coulomb damping force: (1) Among them, the yield stress of magnetorheological fluid With control current They are linearly correlated; It is the dynamic viscosity of the magnetorheological fluid, one of the core physical properties of magnetorheological fluids, and it satisfies: (2) In equation (2), The zero-field yield stress of the magnetorheological fluid; It is the yield stress-current proportionality coefficient of magnetorheological fluid, which is a key parameter for quantifying the "degree of influence of control current on yield stress".

[0040] Since the four MRCs are arranged in parallel, the total damping force is four times the damping force of a single MRC. Substituting into equation (2), we get the total MRC damping force: (3) Equation (3) shows that by adjusting the control current It can change the Coulomb damping force component in real time, achieving millisecond-level stepless adjustment of the damping force to adapt to different impact intensities and load requirements.

[0041] 3.2 Passive Control Model of Double Helical Spring The double helical spring bears the static load of the eVTOL and provides initial impact cushioning. Its elastic force follows Hooke's law. The total elastic force of the four springs connected in parallel is: (4) In equation (4), For a single spring, This represents the spring compression displacement (i.e., the platform's vertical displacement). This model ensures that the spring stably bears the static load under all operating conditions and absorbs the initial impact energy through elastic deformation, laying the foundation for MRC active vibration reduction.

[0042] 3.3 Control Model of Hydraulic Reset Device The core function of the hydraulic system is to achieve horizontal posture reset of the platform. It outputs hydraulic pressure based on closed-loop control of displacement deviation. The total hydraulic pressure consists of elastic force and damping force, satisfying the following: (5) In equation (5), For displacement deviation ( (Initial horizontal position) This is the stiffness coefficient of the hydraulic system. The damping coefficient of the hydraulic system; This is the rate of change of displacement deviation (i.e., deviation velocity).

[0043] To address potential tilting conditions of the platform, a branch control strategy is adopted, with the hydraulic pressures at the four support points as follows: (6) In equation (6), For the first The displacement deviation of each support point is obtained through multi-sensor data fusion to ensure that the platform is accurately restored to a horizontal state.

[0044] 3.4 Active and Passive Coordinated Vibration Reduction Overall Force Model The MRC and double helical springs are arranged in parallel, with each component having the same displacement and velocity. The total synergistic damping force is the algebraic sum of the elastic force and the MRC damping force. (7) Substituting equations (3) and (4) into equation (7), we get: (8) Equation (8) embodies the synergistic mechanism of "passive buffering + active adjustment": the spring bears the static load and initial impact, and the MRC dynamically optimizes the damping force through current adjustment to achieve efficient dissipation of impact energy and vibration isolation.

[0045] 4. Composite Control Algorithm This invention employs a composite algorithm of "PID deviation correction + fuzzy parameter correction" to achieve precise output of control current, adapting to different load and impact conditions.

[0046] 4.1 Basic PID Control Algorithm The core objective of the PID algorithm is to minimize the deviation between the actual acceleration and the set threshold, ensuring vibration reduction accuracy. Defining the deviation... The PID control current in the continuous time domain is: (9) In equation (9), , , These are the proportional, integral, and derivative coefficients, respectively, and their initial values ​​are preset according to the operating conditions (descent phase). , , Settling stage , , ).

[0047] To adapt to digital controller engineering implementation, discretization is adopted (sampling period) The discretized PID current formula is: (10) In equation (10), Sampling time, For the first The instantaneous acceleration deviation ensures the controller's millisecond-level response.

[0048] 4.2 Fuzzy Parameter Correction Algorithm To address the insufficient adaptability of conventional PID parameters under different load and impact intensities, a fuzzy algorithm is introduced to dynamically correct the PID parameters. This is based on the principle of "load level". "and impact strength" "For fuzzy input quantities, use PID parameter correction quantities" , , For the output quantity, the specific implementation is as follows: 1. Fuzziness: Dividing load ratings into... Impact strength is divided into The precise input quantity is converted into a fuzzy quantity by using a triangular membership function; 2. Fuzzy rule base: Preset core rules (example): ① Light load + low impact → , , ② Medium load + medium impact → , , ③ Heavy load + high impact → , , ; 3. Clarification: The fuzzy inference results are converted into precise correction values ​​using the centroid method. The corrected PID parameters are: (11) 4. Fuzzy PID control current: Substituting the corrected parameters into equation (9), the final control current is obtained: (12) Equation (12) realizes the adaptive matching of PID parameters to load and impact conditions, ensuring the optimal vibration reduction effect under different scenarios.

[0049] 5. Multi-condition collaborative control logic 5.1 Operating Condition 1: Platform without eVTOL (standby state) Control objective: Maintain platform performance with low power consumption and be ready at any time; Control logic: The double helical spring is in its naturally extended state, providing basic support; the MRC output has a low standby current. The magnetorheological fluid is kept at a low viscosity and ready for use; the hydraulic device starts with closed-loop attitude control, based on displacement deviation. A small amount of liquid pressure is output to lock the platform in its initial horizontal position, and the sensor continuously monitors and dynamically compensates for minor deviations caused by environmental interference.

[0050] 5.2 Operating Condition 2: eVTOL descent moment (landing impact phase) Control objective: Rapidly absorb impact energy and suppress platform oscillation; Control logic: The sensor detects a sharp increase in acceleration ( This immediately triggers an impact response; the double helix spring absorbs 60% of the impact through elastic deformation. 70% of the initial impact energy; the controller outputs high current instantaneously through a fuzzy PID algorithm (up to [amount missing] under heavy load conditions). The MRC switches to a high-damping state in milliseconds, working with the spring to dissipate the remaining impact kinetic energy and smoothly reduce the vertical velocity of the eVTOL to zero; the hydraulic device does not work actively for the time being, passively following the impact process to avoid interfering with the vibration reduction effect.

[0051] 5.3 Operating Condition 3: eVTOL stationary on the platform (stable parking phase) Control objective: Isolate continuous rotor vibration and maintain platform stability and static load support; Control logic: The double helical spring continuously bears the static load of the eVTOL, preventing the MRC from bearing static loads for a long time; sensors monitor rotor vibration in real time. The controller adjusts the MRC current to a medium-low dynamic range. The damping force is dynamically adjusted through fuzzy PID closed-loop control to actively counteract vibrations of specific frequencies; the hydraulic system continuously monitors the levelness, and if uneven load distribution causes... Output compensation fluid pressure to calibrate attitude.

[0052] 5.4 Operating Condition 4: Platform Reset Phase (After eVTOL Departure) Control objective: Accurately restore the platform to its initial horizontal position; Control logic: When the sensor detects... (The impact ended) and The controller activates the hydraulic device; the hydraulic device outputs precise hydraulic pressure according to formula (6), driving the MRC and spring piston rod to reset; the MRC outputs a low current ( This reduces reset resistance; after the reset is complete, the system switches to standby mode.

[0053] 6. Adaptive learning optimization mechanism To further improve adaptability to multiple aircraft models and operating conditions, this invention introduces an adaptive learning algorithm to optimize control parameters based on historical takeoff and landing data. Define the historical best current ( (Using 10 takeoffs and landings as the historical data period), the optimized control current is obtained by weighted averaging and combining historical experience with current real-time control results: (13) In equation (13), Weighting coefficients ( This approach balances historical optimization experience with current real-time response. By continuously learning the "current-vibration reduction effect" mapping relationship under different machine models and loads, the controller dynamically updates the fuzzy rule base and PID initial parameter base to achieve personalized vibration reduction control, significantly improving the platform's versatility and economy.

[0054] In summary, this invention constructs a complete and efficient intelligent control system through an active-passive collaborative vibration reduction model, a fuzzy PID composite algorithm, multi-condition dynamic adaptation, and adaptive learning optimization. It effectively solves the core problems of poor vibration reduction effect, insufficient adaptability to operating conditions, and weak attitude stability in existing technologies, providing key technical guarantees for the safe and stable take-off and landing of eVTOL.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An active vibration reduction takeoff and landing device for aircraft, characterized in that, It includes a platform mechanism, as well as a vibration damping execution system, a sensor system, and a control system mounted on the platform mechanism, wherein the vibration damping execution system and the sensor system are connected to the control system; The platform mechanism includes a vibration damping platform (1), a base (8) is provided below the vibration damping platform (1), and the vibration damping execution system is supported between the vibration damping platform (1) and the base (8); The vibration damping system includes a telescopic structure (3), a reset hydraulic device (5), and MRC electromagnetic vibration dampers (4). The four corners of the top of the base (8) are connected to the vibration damping platform (1) through the telescopic structure (3). The middle position of the top of the base (8) is connected to the vibration damping platform (1) through the reset hydraulic device (5). Several MRC electromagnetic vibration dampers (4) are provided at equal intervals on the top of the base (8) and outside the reset hydraulic device (5).

2. The active vibration reduction takeoff and landing device for aircraft according to claim 1, characterized in that: The sensor system includes an acceleration sensor (6) embedded in the back of the vibration damping platform (1) and between the MRC electromagnetic vibration damper (4) and the reset hydraulic device (5).

3. The active vibration reduction takeoff and landing device for aircraft according to claim 2, characterized in that: The number of acceleration sensors (6) is the same as that of MRC electromagnetic vibration dampers (4); the acceleration sensors (6) are triaxial acceleration sensors.

4. The active vibration reduction takeoff and landing device for aircraft according to claim 1, characterized in that: The MRC electromagnetic vibration damper (4), the reset hydraulic device (5), and the acceleration sensor (6) are all connected to the controller (7) in the control system.

5. The active vibration reduction takeoff and landing device for aircraft according to claim 1, characterized in that: The telescopic structure (3) uses a double helical spring, with one end of the spring connected to the base (8) and the other end connected to the vibration damping platform (1).

6. The application of an active vibration damping takeoff and landing device as described in any one of claims 1-5 on an eVTOL aircraft.

7. A takeoff and landing method for an aircraft employing the active vibration reduction takeoff and landing device as described in any one of claims 1-5, characterized in that, It includes the following four stages: Standby phase: The telescopic structure is in a naturally extended state, the MRC electromagnetic vibration damper outputs a low standby current, and the magnetorheological fluid maintains a low viscosity and is ready to go; the reset hydraulic device starts the attitude closed-loop control, outputs a small amount of liquid pressure according to the platform displacement deviation Δx, locks the platform in the initial horizontal position, and the sensor system continuously monitors and dynamically compensates for the small displacements caused by environmental interference. During the landing impact phase: The sensors detect a sharp increase in the aircraft's acceleration and immediately trigger an impact response; the telescopic structure absorbs 60% to 70% of the initial impact energy; the controller outputs a high current instantaneously through an algorithm, and the MRC switches to a high-damping state in milliseconds, working in conjunction with the telescopic structure to dissipate the remaining impact kinetic energy and smoothly reduce the eVTOL vertical velocity to zero; the hydraulic device does not actively work and passively follows the impact process to avoid interfering with the vibration reduction effect; During the stable mooring phase: the telescopic structure continuously bears the eVTOL static load, preventing the MRC from bearing static loads for extended periods; sensors monitor rotor vibration in real time, and the controller adjusts the MRC current to a low to medium dynamic current, actively counteracting specific frequency vibrations by adjusting the MRC damping force; the hydraulic system continuously monitors levelness, and if uneven load distribution causes... Output compensation fluid pressure to calibrate attitude; Platform reset phase: When the sensor detects the platform's vertical acceleration ,and The controller activates the hydraulic device; the hydraulic device outputs precise hydraulic pressure to drive the MRC and telescopic structure to reset; the MRC outputs low current to reduce reset resistance; after the reset is completed, the system switches to standby mode.

8. The take-off and landing method of an active vibration reduction take-off and landing device for an aircraft according to claim 7, characterized in that: The control model for the MRC electromagnetic vibration damper is as follows: The damping force model of the MRC electromagnetic vibration damper is derived based on the constitutive properties of the magnetorheological fluid Bingham, as detailed below: The damping force of a single MRC is composed of the superposition of viscous damping force and Coulomb damping force: （1） In equation (1), The dynamic viscosity of a magnetorheological fluid is one of its core physical properties. A This represents the effective working area of ​​the MRC piston. L The length of the magnetorheological fluid channel. d For channel gap, For the platform's vertical speed, The yield stress of the magnetorheological fluid; Among them, the yield stress of magnetorheological fluid With control current They are linearly correlated and satisfy: （2） In equation (2), The zero-field yield stress of the magnetorheological fluid. The yield stress-current proportionality coefficient of magnetorheological fluids is a key parameter for quantifying the influence of control current on yield stress. To control the current; Since the four MRCs are arranged in parallel, the total damping force is four times the damping force of a single MRC. Substituting into equation (2), we get the total MRC damping force: （3） Equation (3) shows that by adjusting the control current It can change the Coulomb damping force component in real time, achieving millisecond-level stepless adjustment of the damping force to adapt to different impact intensities and load requirements.

9. The take-off and landing method of an active vibration reduction take-off and landing device for an aircraft according to claim 7, characterized in that: The double helical springs bear the static load of the eVTOL and provide initial impact cushioning. Their elastic force follows Hooke's law. The total elastic force of the four sets of double helical springs connected in parallel is: （4） In equation (4), For a single spring, This is the spring compression displacement (i.e., the vertical displacement of the platform). The control model for the reset hydraulic device is as follows: based on closed-loop control of displacement deviation, the output hydraulic pressure is determined. The total hydraulic pressure consists of elastic force and damping force, satisfying the following conditions: （5） In equation (5), For displacement deviation ( (Initial horizontal position) This is the stiffness coefficient of the hydraulic system. This refers to the damping coefficient of the hydraulic system. This is the rate of change of displacement deviation (i.e., deviation velocity). To address potential tilting conditions of the platform, a branch control strategy is adopted, with the hydraulic pressures at the four support points as follows: （6） In equation (6), For the first Displacement deviation of each support point.

10. The take-off and landing method of an active vibration reduction take-off and landing device for an aircraft according to claim 7, characterized in that: The active and passive combined vibration reduction total force model formed by the double helical spring and MRC electromagnetic vibration damper: The MRC and double helical springs are arranged in parallel, with each component having the same displacement and velocity. The total synergistic damping force is the algebraic sum of the elastic force and the MRC damping force. （7） Substituting equations (3) and (4) into equation (7), we get: （8）。

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