Helicopter flight safety boundary identification method, device, equipment, medium and product

Abstract

The application discloses a helicopter flight safety boundary identification method, device, equipment, medium and product, relates to the field of helicopters, and comprises the following steps: acquiring terrain information, wind environment information, helicopter design parameters and a motion state; determining wind speed distribution characteristics in a complex environment by using CFD simulation according to the terrain information and the wind environment information; constructing a helicopter flight mechanics model according to the helicopter design parameters and the motion state; coupling the helicopter flight mechanics model and the wind speed distribution characteristics to obtain a helicopter flight mechanics model; determining a threat area according to the wind speed distribution characteristics and the helicopter flight mechanics model; the threat area comprises a wind speed threat area, a control threat area, a posture threat area, a power threat area and a vortex ring threat area; and merging the threat area to determine a flight safety boundary. The application improves the scalability and environmental adaptability of helicopter flight safety boundary identification.

Description

Technical Field

[0001] This application relates to the field of helicopters, and in particular to a method, apparatus, equipment, medium and product for identifying helicopter flight safety boundaries. Background Technology

[0002] Helicopters possess unique vertical takeoff and landing, hovering, and ultra-low-altitude flight capabilities, playing an irreplaceable role in both military and civilian fields. However, when flying in complex environments, they may encounter complex environmental wind fields depending on the terrain. For example, urban building clusters often generate turbulent environments such as backdrafts and street acceleration, while mountainous areas exhibit roller-like airflows and large intermontane backflows. Ships, on the other hand, are surrounded by complex island superstructure shedding vortices. During missions, unstable airflows in the environment directly act on the helicopter rotor blades, generating unsteady pulsating loads that severely affect the helicopter's flight performance and handling characteristics, increasing flight risks. Therefore, conducting research on helicopter flight safety boundaries under various environments can help predict and avoid flight hazard zones caused by complex environmental wind fields, improve helicopter survivability, and guide flight strategy design. Summary of the Invention

[0003] The purpose of this application is to provide a method, apparatus, equipment, medium, and product for identifying helicopter flight safety boundaries, which can improve the scalability and environmental adaptability of helicopter flight safety boundary identification.

[0004] To achieve the above objectives, this application provides the following solution:

[0005] Firstly, this application provides a method for identifying helicopter flight safety boundaries, including:

[0006] Acquire terrain information, wind environment information, helicopter design parameters, and motion status;

[0007] Based on the terrain information and the wind environment information, CFD simulation is used to determine the wind speed distribution characteristics under complex environments;

[0008] A helicopter flight dynamics model is constructed based on the helicopter design parameters and the motion state.

[0009] The helicopter flight dynamics model is coupled with the wind speed distribution characteristics to obtain the helicopter flight dynamics model;

[0010] Threat zones are determined based on the wind speed distribution characteristics and the helicopter flight dynamics model; the threat zones include wind speed threat zones, control threat zones, attitude threat zones, power threat zones, and vortex ring threat zones;

[0011] The threat zones are merged to determine the flight safety boundary.

[0012] Optionally, based on the terrain information and the wind environment information, CFD simulation is used to determine the wind speed distribution characteristics under complex environments, specifically including:

[0013] Extract terrain features based on the terrain information;

[0014] The average wind speed at different altitudes is determined based on the wind environment information.

[0015] The initial parameters of the flow field are set, and the flow field is subjected to CFD simulation based on the terrain features and the average wind speed at different heights to obtain the wind speed distribution characteristics under complex conditions.

[0016] Optionally, a helicopter flight dynamics model is constructed based on the helicopter design parameters and the motion state, specifically including:

[0017] Based on the helicopter design parameters and the motion state, interpolation is performed to solve for the mechanical information of each component at the aerodynamic center; the mechanical information includes triaxial forces and moments.

[0018] Based on the mechanical information of each component at the aerodynamic center, coordinate transformation is performed to obtain the mechanical information of the entire aircraft's center of gravity.

[0019] Based on the mechanical information at the center of gravity of the entire aircraft, a helicopter flight mechanics model is constructed according to the six-degree-of-freedom rigid body motion equation.

[0020] Optionally, the threat zone is determined based on the wind speed distribution characteristics and the helicopter flight dynamics model, specifically including:

[0021] The wind speed threat area is determined based on the environmental velocity field and turbulent kinetic energy distribution with the aforementioned distribution characteristics.

[0022] Based on the helicopter flight dynamics model, a spatial operation characteristic cloud map is determined using joystick values.

[0023] The manipulation threat area is determined based on the spatial operation feature cloud map and the joystick margin threshold.

[0024] Based on the helicopter flight dynamics model, a spatial attitude feature cloud map is determined using the helicopter attitude angle values.

[0025] The attitude threat region is determined based on the spatial attitude feature cloud map and attitude angle threshold.

[0026] Based on the helicopter flight dynamics model, a spatial power characteristic cloud map is determined according to the helicopter's required power.

[0027] The power threat region is determined based on the spatial power characteristic cloud map and power threshold.

[0028] Based on the helicopter dynamics model, the vortex ring limitation criterion is determined according to the ambient wind speed, rotor induced velocity, and tail rotor induced velocity.

[0029] The vortex ring threat region is determined based on the vortex ring limitation criterion.

[0030] Optionally, the joystick margin threshold is that the joystick margin for each channel is greater than 10%.

[0031] Optionally, the power threshold is a helicopter engine margin greater than 10%.

[0032] Secondly, this application provides a helicopter flight safety boundary identification device, comprising:

[0033] The acquisition module is used to acquire terrain information, wind environment information, helicopter design parameters, and motion status.

[0034] The distribution feature determination module is used to determine the wind speed distribution features under complex environments using CFD simulation based on the terrain information and the wind environment information.

[0035] The construction module is used to construct a helicopter flight dynamics model based on the helicopter design parameters and the motion state;

[0036] The coupling module is used to couple the helicopter flight dynamics model with the wind speed distribution characteristics to obtain the helicopter flight dynamics model;

[0037] The threat zone determination module is used to determine the threat zone based on the wind speed distribution characteristics and the helicopter flight dynamics model; the threat zone includes a wind speed threat zone, a control threat zone, an attitude threat zone, a power threat zone, and a vortex ring threat zone;

[0038] The flight safety boundary determination module is used to merge the threat areas to determine the flight safety boundary.

[0039] Thirdly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the helicopter flight safety boundary identification method described in any one of the above.

[0040] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the helicopter flight safety boundary identification method described above.

[0041] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the helicopter flight safety boundary identification method described above.

[0042] According to the specific embodiments provided in this application, this application has the following technical effects:

[0043] This application provides a helicopter flight safety boundary identification method, device, equipment, medium, and product. By determining the wind speed distribution characteristics in complex environments based on terrain and wind environment information, and coupling the wind speed distribution characteristics with the helicopter flight mechanics model, the method takes into account the characteristics of the environmental wind field, forming a helicopter flight safety analysis method based on environment-helicopter coupling. This improves environmental adaptability and constructs a threat zone based on wind speed, control, attitude, power, and vortex ring factors, thereby further improving scalability and environmental adaptability. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is an application environment diagram of a helicopter flight safety boundary identification method according to an embodiment of this application;

[0046] Figure 2 A flowchart illustrating a helicopter flight safety boundary identification method provided in one embodiment of this application;

[0047] Figure 3 This is a schematic flowchart of a helicopter flight safety boundary identification method provided in an embodiment of this application;

[0048] Figure 4 A CFD solution flowchart for a helicopter flight safety boundary identification method provided in an embodiment of this application;

[0049] Figure 5 This is a structural diagram of a flight dynamics model provided in an embodiment of this application;

[0050] Figure 6 This is a simulated environmental wind speed characteristic map provided in one embodiment of this application;

[0051] Figure 7 This is a schematic diagram of discrete analysis points in the spatial domain surrounding a mountain, provided in an embodiment of this application.

[0052] Figure 8 This is a schematic diagram of discrete analysis points in the spatial domain surrounding a building, provided in an embodiment of this application.

[0053] Figure 9A spatial operation feature cloud map provided in an embodiment of this application;

[0054] Figure 10 A spatial attitude feature cloud map provided in an embodiment of this application;

[0055] Figure 11 Spatial power characteristic cloud map provided in an embodiment of this application;

[0056] Figure 12 This is a schematic diagram of the vortex ring threat zone in a helicopter under balanced conditions, provided in an embodiment of this application.

[0057] Figure 13 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0058] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0059] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] To date, there is no universally applicable analytical method for the study of helicopter flight safety boundaries in complex environments. Traditionally, safety analyses under large-scale flow field disturbances involve analyzing the helicopter's balance characteristics at key points along the takeoff and landing routes, using wind speed and direction limits at these points as safety boundaries. However, real-world flight missions are diverse, making it difficult to establish a unified flight route description. Furthermore, single-point studies cannot effectively assess potential systemic risks, and simply obtaining environmental wind constraints cannot compensate for specific threats. Therefore, this application provides a helicopter flight safety boundary identification method based on the coupling of aerodynamics and flight mechanics. This method is used for dynamic safety boundary identification of helicopters flying in complex environments (mountains, cities, ships, etc.). The method performs terrain modeling and accurate wind field numerical simulation of the complex environment. Then, it discretizes the environmental spatial domain and selects analysis points in key wind field areas. It then performs in-depth calculations of the helicopter's overall balance characteristics at these analysis points. Finally, it compares these calculations with helicopter control, attitude, power, and vortex ring limitations to obtain the dynamic safety boundary of the helicopter flying in complex environments. This method involves the fields of rotorcraft flight dynamics and computational fluid dynamics. Based on helicopter operation specifications, a comprehensive analysis is conducted on environmental wind field, control stroke, fuselage attitude, power consumption and vortex ring limitations. Environmental threat criteria are formulated, and the limitations of environmental obstacles on the pilot's field of vision and control space are comprehensively considered to form a dynamic flight safety boundary for helicopters in the environmental space, providing guidance for safe helicopter flight.

[0061] The helicopter flight safety boundary identification method provided in this application embodiment can be applied to, for example... Figure 1In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be set up independently, integrated into server 104, or placed in the cloud or on another server. Terminal 102 can send terrain information, wind environment information, helicopter design parameters, and motion status to be processed to server 104. After receiving the terrain information, wind environment information, helicopter design parameters, and motion status, server 104 uses CFD simulation to determine the wind speed distribution characteristics under complex conditions based on the terrain information and wind environment information; constructs a helicopter flight dynamics model based on the helicopter design parameters and motion status; couples the helicopter flight dynamics model with the wind speed distribution characteristics to obtain a helicopter flight dynamics model; determines threat zones based on the wind speed distribution characteristics and the helicopter flight dynamics model; the threat zones include wind speed threat zones, control threat zones, attitude threat zones, power threat zones, and vortex ring threat zones; and merges the threat zones to determine the flight safety boundary. Server 104 can feed back the obtained flight safety boundary to terminal 102. Furthermore, in some embodiments, the helicopter flight safety boundary identification method can also be implemented by either server 104 or terminal 102 independently. For example, terminal 102 can directly identify the flight safety boundary based on terrain information, wind environment information, helicopter design parameters, and motion status; alternatively, server 104 can obtain terrain information, wind environment information, helicopter design parameters, and motion status from the data storage system and then identify the flight safety boundary based on these parameters.

[0062] The terminal 102 can be, but is not limited to, various desktop computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices. IoT devices can include smart speakers, smart TVs, smart air conditioners, and smart in-vehicle devices. Portable wearable devices can include smartwatches, smart bracelets, and head-mounted devices. The server 104 can be implemented using a standalone server or a server cluster composed of multiple servers, or it can be a cloud server.

[0063] In one exemplary embodiment, such as Figure 2 As shown, a method for identifying helicopter flight safety boundaries is provided. This method is executed by computer equipment, specifically by a terminal or server alone, or by both a terminal and a server. In this embodiment, the method is applied to... Figure 1 Taking server 104 as an example, the explanation includes the following steps 201 to 206. Wherein:

[0064] Step 201: Obtain terrain information, wind environment information, helicopter design parameters, and motion status.

[0065] Step 202: Based on the terrain information and the wind environment information, use CFD simulation to determine the wind speed distribution characteristics under complex environments.

[0066] Step 203: Construct a helicopter flight dynamics model based on the helicopter design parameters and the motion state.

[0067] Step 204: Couple the helicopter flight dynamics model with the wind speed distribution characteristics to obtain the helicopter flight dynamics model.

[0068] Step 205: Determine the threat zone based on the wind speed distribution characteristics and the helicopter flight dynamics model; the threat zone includes the wind speed threat zone, the control threat zone, the attitude threat zone, the power threat zone, and the vortex ring threat zone.

[0069] Step 206: Merge the threat zones to determine the flight safety boundary.

[0070] Implementing steps 201 to 206 above can improve the scalability and environmental adaptability of helicopter flight safety boundary identification.

[0071] In one exemplary embodiment, step 202 specifically includes:

[0072] Topographic features are extracted based on the topographic information. Average wind speeds at different altitudes are determined based on the wind environment information. Initial flow field parameters are set, and CFD simulations are performed on the flow field based on the topographic features and average wind speeds at different altitudes to obtain wind speed distribution characteristics under complex environments.

[0073] In practical applications, the first step is to conduct environmental modeling and wind field simulation. By establishing typical terrain and average wind models, CFD simulation is used to obtain the wind speed distribution characteristics in complex environments. The wind speed at different locations is then superimposed on the flight dynamics model to affect the overall aircraft balance characteristics, and is also used for the delineation of environmental wind speed threat zones. The specific steps include the following:

[0074] The first step is to establish a typical terrain / environmental obstacle model. To establish a typical terrain / environmental obstacle model, we first extract typical terrain features from the environment. For natural environment modeling, we only focus on topographic relief, and for urban area modeling, we only consider the overall shape of buildings, etc. After establishing a simplified terrain geometry, we draw the unstructured mesh required for CFD analysis.

[0075] The second step is to establish a wind environment model. The wind environment model only considers the mean wind characteristics, describing the mean wind profile according to the exponential law. The profile wind speed is used as the wind speed at the corresponding height, which is then used as the far-field inflow velocity to form the CFD inlet boundary conditions. For the exponential wind profile, the expression for the variation of the mean wind speed along height is as follows:

[0076]

[0077] In the formula, z0 and These represent the standard reference height and the average wind speed at the standard reference height, respectively. According to the national standard wind force classification, 10m is used as the average wind reference height; z and α represents the average wind speed at any altitude and α represents the ground roughness index.

[0078] The third step is to read the configuration file. The configuration file sets the parameters required for CFD calculations. Organized in JSON format, the configuration file describes each grid block and its filename, including initial flow field parameters (determining the incoming flow velocity using the aforementioned mean wind profile), solution control parameters (spatial / temporal discretization scheme and turbulence model for each grid block, unsteady time step, maximum calculation iteration step, etc.), post-processing, and output settings. The control parameters, post-processing, and output settings are all pre-defined.

[0079] The fourth step is to solve the flow field. The computational domain is set as a cuboid. Impenetrable surfaces such as environmental terrain / obstacles are designated as walls, while other permeable boundaries (allowing free flow of fluid) are set as free-flow conditions. The velocity input uses the average wind synthesized in the second step. A CFD simulation is then performed. Once the calculation converges, the following results can be obtained: Figure 6 The diagram shows the distribution characteristics of wind speed, including velocity, pressure, density, and turbulent kinetic energy, within the flow field. Figure 6 (a) shows the windward velocity distribution around the mountain. Figure 6 (b) shows the vertical wind speed distribution around the mountain.

[0080] like Figure 4 The established CFD solver flow is as follows: 1) Read the configuration, which describes the initial flow field parameters and solution control parameters; 2) Read the mesh file, discretizing the terrain geometry model into an unstructured mesh format usable by CFD; 3) Initialize the flow field, using an exponential mean wind profile to directly assign values ​​to the global flow field, reducing the convergence time of subsequent calculations; 4) Solve the flow field, selecting the spatial / temporal discretization format and turbulence model according to the solution configuration of the corresponding mesh blocks, and performing iterative calculations; 5) Output and post-processing, outputting the wind speed and turbulent kinetic energy at the grid points within the computational domain for subsequent analysis.

[0081] In one exemplary embodiment, step 203 specifically includes:

[0082] Based on the helicopter design parameters and the motion state, interpolation is performed to solve for the mechanical information of each component at the aerodynamic center; the mechanical information includes triaxial forces and torques.

[0083] Based on the mechanical information of each component at the aerodynamic center, coordinate transformation is performed to obtain the mechanical information of the entire aircraft's center of gravity.

[0084] Based on the mechanical information at the center of gravity of the entire aircraft, a helicopter flight mechanics model is constructed according to the six-degree-of-freedom rigid body motion equation.

[0085] In practical applications, after completing the CFD simulation, flight dynamics modeling is performed to analyze the balance characteristics of helicopters flying in complex environments. First, the coordinate transformation relationships between components need to be established. Then, aerodynamic models are established for each component. An interface for coupling environmental wind speed is reserved in the resultant velocity solution module for each component, allowing the influence of environmental wind speed to be introduced during calculation. Differences in aerodynamic forces and moments of components under different environmental winds will ultimately affect the overall aircraft balance characteristics. Steps 203 and 204 specifically include the following steps:

[0086] The first step is to establish coordinate transformation relationships. An inertial coordinate system is established and fixed to the ground, using the Earth's surface as a reference. The body coordinate system is obtained based on attitude angles, and the wind axis system is determined according to the body's angle of attack and sideslip angle. Rotor calculations need to consider the motion of individual blades; therefore, a hub coordinate system is obtained based on the hub's longitudinal and lateral installation angles. An azimuth angle is then introduced to establish the rotor rotation coordinate system, and finally, the blade coordinate system is obtained based on the blade flapping motion. If the tail rotor shaft is not perpendicular to the body's longitudinal plane, a transformation relationship between the tail rotor coordinate system and the body coordinate system needs to be established using the tail rotor tilt angle. These transformation relationships are then formed into a matrix. Multiplying vectors by the matrix allows for the conversion of the three-dimensional forces and moments of each component between any coordinate system.

[0087] The second step is to establish aerodynamic models of the components. Based on the helicopter's design parameters (size, mass, shape) and motion states (speed, angular velocity, acceleration, angular acceleration), considering the mutual interference between components, and combining the lift and drag coefficients of each component in wind tunnel tests, the forces and moments of each component at its aerodynamic center are interpolated and solved. Through the coordinate transformation in the first step, the three-dimensional forces and moments of all components are integrated into the center of gravity of the entire aircraft. Finally, a helicopter flight dynamics model is formed based on the six-degree-of-freedom rigid body motion equations.

[0088] The dynamic equations for the movement of the helicopter's center of gravity and its rotation about the center of gravity are as follows:

[0089]

[0090] Where u, v, and w are the velocity components along the horizontal axis of the aircraft, the longitudinal axis of the aircraft, and the vertical axis of the aircraft, respectively. Let be the velocity derivatives along the horizontal, vertical, and y axes of the aircraft; p, q, and r are the angular velocities along the horizontal, vertical, and y axes of the aircraft, respectively. F represents the derivatives of the angular velocities along the horizontal, vertical, and longitudinal axes of the aircraft; m represents the mass; F represents the angular velocity derivatives along the horizontal, vertical, and longitudinal axes of the aircraft. X F Y F Z L represents the force along the horizontal, vertical, and lateral axes of the aircraft; M and N represent the moments about the horizontal, vertical, and lateral axes of the aircraft, respectively; I and ω represent the forces along the horizontal, vertical, and lateral axes of the aircraft, respectively. * Let represent the cross product of the inertia matrix and the angular velocity, respectively.

[0091]

[0092] Among them, I XX Let I be the moment of inertia of the body about the X-axis. XZ I is the product of the inertia of the body about the X and Z axes. YY Let I be the moment of inertia of the body about the Y-axis. ZZ Let I be the moment of inertia of the body about the Z-axis. ** These are all design parameters.

[0093] Combining the propeller flapping motion equations with the helicopter rigid body dynamics equations yields the helicopter flight dynamics model, which is simplified as follows:

[0094]

[0095] Where t is time; U is the control variable, including collective pitch, lateral and longitudinal cyclic pitch, and tail rotor collective pitch; X is the state variable, including velocity, angular velocity, and attitude angle; W wind For ambient wind speed, The derivative of the state variable.

[0096] The third step is wind field data processing and data coupling. Since CFD calculation results are stored on unstructured grid points, the results are interpolated and stored in a structured manner. A wind field file containing scattered location coordinates and three-dimensional wind speed information is provided to the flight dynamics model. In the flight dynamics model, the wind speed at the aerodynamic center of the component is obtained through position interpolation. The ambient wind speed is decomposed according to the aircraft's lateral, longitudinal, and vertical directions. The coupling between the ambient wind field and the bare aircraft model is achieved by superimposing the wind speed and motion velocity at the component's aerodynamic center. This establishes the flight dynamics model, which can solve for the helicopter's downwash velocity, control parameters, attitude, and power in equilibrium under complex wind fields.

[0097] like Figure 5The flight dynamics model structure shown is as follows: Based on helicopter design parameters, such as component center-of-mast positions and geometric dimensions, aerodynamic models of the rotor, tail rotor, fuselage, and tail surface are established respectively. When modeling the rotor, the blades are divided into several micro-segments, retaining the first-order flapping motion. The rotor downwash velocity is calculated through dynamic inflow. External wind field velocities and inter-component interference velocities are superimposed onto the micro-segment centers and the aerodynamic centers of other components through position interpolation. Finally, by simultaneously solving the blade flapping motion equations and the helicopter's six-degree-of-freedom rigid body dynamics equations, the bare-metal flight dynamics model of the helicopter can be obtained. Using this model, the downwash velocities of the rotor and tail rotor in equilibrium, helicopter control, attitude, and power consumption can be calculated. Figure 7 and Figure 8 These are discrete analysis points set according to environmental characteristics in mountainous and building-surrounding environments. The analysis points should be taken in the key influence areas of the windward side and the leeward return flow. The equilibrium characteristics can be further calculated at the grid points in the figure using flight dynamics models.

[0098] In an exemplary embodiment, step 205 specifically includes:

[0099] The wind speed threat area is determined based on the environmental velocity field and turbulent kinetic energy distribution of the aforementioned distribution characteristics.

[0100] Based on the helicopter flight dynamics model, a spatial operation characteristic cloud map is determined using joystick values.

[0101] The control threat area is determined based on the spatial operation feature cloud map and the joystick margin threshold.

[0102] Based on the helicopter flight dynamics model, a spatial attitude feature cloud map is determined using the helicopter attitude angle values.

[0103] The attitude threat region is determined based on the spatial attitude feature cloud map and attitude angle threshold.

[0104] Based on the helicopter flight dynamics model, a spatial power characteristic cloud map is determined according to the helicopter's required power.

[0105] The power threat region is determined based on the spatial power feature cloud map and power threshold.

[0106] The vortex ring limiting criterion is determined based on the helicopter dynamics model, using ambient wind speed, rotor induced velocity, and tail rotor induced velocity.

[0107] The vortex ring threat region is determined based on the vortex ring limitation criterion.

[0108] In practical applications, the joystick margin threshold is a margin of more than 10% for each channel joystick. The power threshold is a margin of more than 10% for the helicopter engine.

[0109] Specifically, the environmental wind speed threat zone is divided based on wind field speed and turbulent kinetic energy characteristics, and the control, attitude, power, and vortex ring threat zones are divided based on the results of the overall aircraft balance characteristic analysis. The envelope of these five threat zones is then used as the flight safety boundary. This process includes the following steps:

[0110] The first step is to delineate the wind speed threat area. First, the environmental velocity field and turbulent kinetic energy distribution obtained in the fourth step of the wind field simulation are analyzed, specifically limited to an environmental vertical velocity standard deviation not exceeding 1.75 m / s and turbulent kinetic energy not exceeding 4.59 m. 2 / s 2 The area exceeding the limit was divided into wind speed threat zones that threaten helicopter safety in the environment. Key impact zones in the environment were selected based on wind speed characteristics, and discrete analysis points were set within these key impact zones, taking into account both obstacle and helicopter dimensions.

[0111] The second step is to delineate the areas where threats can be manipulated. For example... Figure 9 As shown, where Figure 9 (a) in the diagram is a spatial control feature cloud map of the collective pitch lever. Figure 9 (b) shows the spatial control characteristic cloud map of the longitudinal stick values. Using a flight dynamics model, the helicopter's center of mass is placed at the analysis point. Considering the influence of ambient wind (wind speed interpolation interface is enabled), a full-aircraft balance characteristic analysis is conducted. The stick values ​​at each discrete point are displayed on a single graph in different colors to form the spatial control characteristic cloud map. A stick margin of more than 10% in each channel is considered safe, i.e., the collective pitch propulsion is limited to 10% < δ. col <90%, pedal operation amount is limited to 10% <δ ped <90%, lateral joystick movement is limited to 10% <δ lat <90%, longitudinal control lever range limited to 10% <δ lon <90%, exceeding the limit, is considered a manipulation threat zone.

[0112] The third step is to delineate the posture threat zone. For example... Figure 10 As shown, where Figure 10 (a) in the figure is a spatial attitude feature cloud map of the roll angle, where Figure 10Image (b) shows the spatial attitude characteristic cloud map of the pitch angle. Using a flight dynamics model, the helicopter's center of mass is placed at the analysis point. Considering the influence of ambient wind (wind speed interpolation interface is enabled), a full-aircraft balance characteristic analysis is conducted. The helicopter attitude angle values ​​at each discrete point are displayed in different colors to form a spatial attitude characteristic cloud map, distinguished by helicopter model and degree of environmental obstacles. In comparison, the safe range of attitude angles is smaller for smaller helicopters and in confined spaces, while the restrictions can be appropriately relaxed. For example, in mountainous environments, the attitude restrictions for a UH-60A helicopter are roll angle -8° < Φ < 8° and pitch angle -4° < Θ < 7°; while in urban environments, the restrictions for the same model of helicopter can be adjusted to roll angle -6° < Φ < 6° and pitch angle -4° < Θ < 6°. The area exceeding the limits is the attitude threat zone.

[0113] The fourth step is to delineate the power threat zone. If Figure 11 As shown, where Figure 11 (a) in the image is a cloud map showing the characteristic power demand of helicopters in the wind field surrounding the building. Figure 11 (b) in the diagram represents the power demand characteristic cloud map in a mountainous environment. Using flight dynamics models, balance characteristic analysis can also obtain the power consumed by the rotor and tail rotor when the helicopter maintains balance. The sum of these two values ​​represents the power demand of the helicopter at the spatial analysis point. The power demand values ​​at each discrete point are displayed in different colors to form a spatial power characteristic cloud map. Combined with the helicopter's engine type and power, a 10% engine margin is required for safety. For example, the UH-60A helicopter is equipped with two General Electric T700-GE-700 turboshaft engines, each with a power output of 1165kW. When the power demand exceeds 2097kW, it enters the power threat zone. The Z-11 helicopter, equipped with one WZ-8D turboshaft engine, is limited to 440kW. When the power demand exceeds 396kW, it enters the power threat zone.

[0114] The fifth step is to delineate the vortex ring threat zone. Using a flight dynamics model, equilibrium characteristic analysis can be performed to obtain the rotor and tail rotor induced velocities at the helicopter's equilibrium state. Combining the Peters vortex ring criterion and the Gauth-Symplocane vortex ring criterion, a vortex ring limiting criterion is formed based on ambient wind speed and the rotor and tail rotor induced velocities. Peters, based on dynamic inflow theory and momentum theory, proposed that when the free flow velocity vector... In the wake velocity vector When the projection on the rotor is negative, the rotor enters the vortex ring state, that is, the analytical expression of the vortex ring boundary is:

[0115]

[0116] Where v0 is the rotor equivalent induced velocity at the rotor disk; V x yes The horizontal component (positive for forward flight); Vy yes The vertical component (positive for rising). According to the Peters boundary, the horizontal velocity component V... x Greater than 0.62v h (v h (To induce speed for rotating components), the helicopter will not enter a vortex ring state.

[0117] The Gauzynskiy criterion states that when the projection of the free-flow velocity vector onto the rotor wake velocity vector in the opposite direction exceeds a certain critical value, the rotor enters a vortex ring state. This critical value is exactly equal to the critical velocity V required to enter the vortex ring state during vertical descent. y The experiment obtained the critical velocity V for entering the vortex ring state during vertical descent. y equals 0.28v h (v h (To induce velocity for the rotating component). Therefore:

[0118]

[0119] Since the helicopter remains relatively stationary relative to the obstacle during spatial domain analysis, the aircraft's velocity is converted into an environmental wind speed criterion. Furthermore, because the helicopter has multiple rotating components, in this application, for the rotor: the environmental horizontal wind speed must be greater than 0.62v. h For the safety zone, the ambient vertical wind speed is greater than 0.28V. h This is a vortex ring threat zone; for the tail rotor: ambient horizontal wind speed greater than 0.62v. h For the safety zone, the ambient lateral wind speed is greater than 0.28V. h The vortex ring is the threat zone, and the intermediate speed range is the transition zone.

[0120] like Figure 12 This is a schematic diagram of the vortex ring boundary in the near-building area of ​​a helicopter under equilibrium conditions, defined by environmental velocity. Figure 12 (a) in the diagram is a schematic diagram of the rotor vortex ring confinement zone under building wind field conditions. Figure 12 (b) is a schematic diagram of the tail rotor vortex ring confinement zone under the building wind field. The white area has a relatively high horizontal velocity and no vortex ring danger. Entering the blue area indicates that the ambient horizontal wind speed is less than 0.62v. h The orange area indicates that the environmental vertical velocity is greater than 0.28v. h Thus, the overlapping area of ​​the two is the vortex ring threat zone.

[0121] Step six: Establish the dynamic flight safety boundary in the space domain. Steps one through five above have yielded the threat zones for wind speed, control, attitude, power, and vortex rings, respectively. These five threat zones are merged into a comprehensive environmental threat zone. The envelope of this threat zone represents the flight safety boundary under this complex environment. As environmental parameters such as wind speed, wind direction, and altitude change, the extent of the threat zone also changes. Following the same steps, the dynamic flight safety boundary that varies with environmental wind conditions can be obtained.

[0122] This application addresses the safety requirements of helicopters flying in complex environments, breaking through key technologies in multidisciplinary coupled modeling and flight safety design for helicopter flight, and establishing a spatial domain helicopter dynamic behavior safety boundary identification technology based on "environment-helicopter" coupling. According to the requirements of helicopter flight missions in complex environments, CFD and flight mechanics methods are applied to helicopter flight simulation and flight safety boundary design research. A numerical simulation method for environmental wind fields is established based on unsteady RANS equations, and a helicopter flight mechanics model coupled with environmental wind field characteristics is established. Analysis of helicopter control, attitude, power consumption, and vortex ring threat is conducted at discrete points in the spatial domain. Furthermore, combined with environmental wind speed criteria, a comprehensive dynamic flight safety boundary for the helicopter is formed.

[0123] like Figure 3 The technical solution shown is as follows:

[0124] The first step is to model the terrain and wind field environment. First, typical simplified terrains of various complex terrains are established, such as isolated hills in mountainous environments and isolated buildings in cities. The terrain environment model is established and the wind field model is described by the mean wind profile, providing the geometric and inflow velocity conditions required for CFD calculations.

[0125] The second step is wind field simulation and data processing. The geometry and inflow velocity obtained in the first step are input into the CFD calculation program. An average wind profile is formed according to the environmental characteristics as the far-field boundary, and CFD numerical simulation calculations are carried out to obtain the flow field velocity and turbulent kinetic energy distribution. On the one hand, this can be used for the delineation of wind speed hazard zones. On the other hand, by inputting the flow field velocity into the flight dynamics model, the coupling between the environment and the helicopter is realized, introducing the interference of the environment on the helicopter.

[0126] The third step is flight dynamics modeling and wind field interpolation. A physical model-based flight dynamics model is established, which can perform overall aircraft balance characteristic calculations at predetermined speeds. Based on the helicopter's configuration parameters, aerodynamic models of each component are established, and a flight mechanics analysis model is formed according to the six-degree-of-freedom rigid body motion equations. The three-dimensional velocities of the flow field obtained by CFD are interpolated and superimposed at the aerodynamic centers of each helicopter component, realizing the coupling of CFD and flight mechanics models.

[0127] The fourth step is environmental spatial domain discretization and flight threat analysis. Key areas near environmental obstacles are discretized to form analysis points, such as mountain peaks, windward slopes, and leeward sides in mountainous environments, and rooftops, sides, windward sides, and leeward sides of buildings near structures. A full-aircraft balance characteristic analysis is performed on these analysis points, and control, attitude, power, and vortex ring threat areas are delineated based on helicopter model limitations. Combining the wind field data obtained in the second step, wind speed threat areas are delineated according to the vertical velocity mean square error and turbulent kinetic energy limits.

[0128] Step 5: Flight safety boundary identification. The five threat zones obtained in Step 4 are combined, and the area outside all threat zones is the safe flight zone. The envelope of the threat zones forms the flight safety boundary in space. The safety boundary changes with environmental wind speed and helicopter flight status, hence it is called the dynamic flight safety boundary.

[0129] Through the above steps, a spatial domain helicopter flight safety boundary analysis method applicable to various complex environments is proposed for the first time. Addressing the safety flight requirements of helicopters in complex environments, terrain and wind environment modeling and analysis are conducted based on environmental wind field characteristics. By establishing a helicopter flight dynamics model, helicopter balance characteristic analysis can be achieved, forming a helicopter flight safety analysis technology based on "environment-helicopter" coupling. Facing problems such as control failure and attitude exceeding limits caused by turbulent wind fields in complex environments, a safe flight boundary considering factors such as control, attitude, power, and vortex rings is constructed. The analysis method has good scalability and environmental adaptability.

[0130] Based on the same inventive concept, this application also provides a helicopter flight safety boundary identification device for implementing the helicopter flight safety boundary identification method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the helicopter flight safety boundary identification device provided below can be found in the limitations of the helicopter flight safety boundary identification method described above, and will not be repeated here.

[0131] In one exemplary embodiment, a helicopter flight safety boundary identification device is provided, comprising:

[0132] The acquisition module is used to acquire terrain information, wind environment information, helicopter design parameters, and motion status.

[0133] The distribution feature determination module uses CFD simulation to determine the wind speed distribution features under complex environments based on the terrain information and the wind environment information.

[0134] The construction module is used to construct a helicopter flight dynamics model based on the helicopter design parameters and the motion state;

[0135] The coupling module is used to couple the helicopter flight dynamics model with the wind speed distribution characteristics to obtain the helicopter flight dynamics model;

[0136] The threat zone determination module is used to determine the threat zone based on the wind speed distribution characteristics and the helicopter flight dynamics model; the threat zone includes a wind speed threat zone, a control threat zone, an attitude threat zone, a power threat zone, and a vortex ring threat zone;

[0137] The flight safety boundary determination module is used to merge the threat areas to determine the flight safety boundary.

[0138] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 13 As shown, the computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores flight safety boundary data. The I / O interfaces are used for information exchange between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When executed by the processor, the computer program implements a helicopter flight safety boundary identification method.

[0139] Those skilled in the art will understand that Figure 13 The structures shown are merely block diagrams of some structures related to the present application and do not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than shown in the figures, or combine certain components, or have different component arrangements. In an exemplary embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method embodiments.

[0140] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the above-described method embodiments.

[0141] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the above-described method embodiments.

[0142] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0143] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0144] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchain. The processors involved in the embodiments provided in this application may be, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc.

[0145] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0146] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for identifying helicopter flight safety boundaries, characterized in that, The helicopter flight safety boundary identification method includes: Acquire terrain information, wind environment information, helicopter design parameters, and motion status; Based on the terrain information and the wind environment information, CFD simulation is used to determine the wind speed distribution characteristics under complex environments; A helicopter flight dynamics model is constructed based on the helicopter design parameters and the motion state. The helicopter flight dynamics model is coupled with the wind speed distribution characteristics to obtain the helicopter flight dynamics model; The threat zone is determined based on the wind speed distribution characteristics and the helicopter flight dynamics model, specifically including: determining the wind speed threat zone based on the environmental velocity field and turbulent kinetic energy distribution of the distribution characteristics; determining the spatial operation characteristic cloud map based on the control stick values ​​according to the helicopter flight dynamics model; determining the controllability threat zone based on the spatial operation characteristic cloud map and the control stick margin threshold; determining the spatial attitude characteristic cloud map based on the helicopter attitude angle values ​​according to the helicopter flight dynamics model; determining the attitude threat zone based on the spatial attitude characteristic cloud map and the attitude angle threshold; determining the spatial power characteristic cloud map based on the helicopter power demand according to the helicopter flight dynamics model; determining the power threat zone based on the spatial power characteristic cloud map and the power threshold; determining the vortex ring limitation criterion based on the environmental wind speed, rotor induced velocity, and tail rotor induced velocity according to the helicopter dynamics model; and determining the vortex ring threat zone based on the vortex ring limitation criterion. The threat zone includes the wind speed threat zone, the controllability threat zone, the attitude threat zone, the power threat zone, and the vortex ring threat zone. The threat zones are merged to determine the flight safety boundary.

2. The helicopter flight safety boundary identification method according to claim 1, characterized in that, Based on the terrain information and the wind environment information, CFD simulation is used to determine the wind speed distribution characteristics under complex environments, specifically including: Extract terrain features based on the terrain information; The average wind speed at different altitudes is determined based on the wind environment information. The initial parameters of the flow field are set, and the flow field is subjected to CFD simulation based on the terrain features and the average wind speed at different heights to obtain the wind speed distribution characteristics under complex conditions.

3. The helicopter flight safety boundary identification method according to claim 1, characterized in that, Based on the helicopter design parameters and the motion state, a helicopter flight dynamics model is constructed, specifically including: Based on the helicopter design parameters and the motion state, interpolation is performed to solve for the mechanical information of each component at the aerodynamic center; the mechanical information includes triaxial forces and moments. Based on the mechanical information of each component at the aerodynamic center, coordinate transformation is performed to obtain the mechanical information of the entire aircraft's center of gravity. Based on the mechanical information at the center of gravity of the entire aircraft, a helicopter flight mechanics model is constructed according to the six-degree-of-freedom rigid body motion equation.

4. The helicopter flight safety boundary identification method according to claim 1, characterized in that, The joystick margin threshold is that the joystick margin of each channel is greater than 10%.

5. The helicopter flight safety boundary identification method according to claim 1, characterized in that, The power threshold is defined as a helicopter engine margin greater than 10%.

6. A helicopter flight safety boundary identification device, characterized in that, The helicopter flight safety boundary identification device includes: The acquisition module is used to acquire terrain information, wind environment information, helicopter design parameters, and motion status. The distribution feature determination module is used to determine the wind speed distribution features under complex environments using CFD simulation based on the terrain information and the wind environment information. The construction module is used to construct a helicopter flight dynamics model based on the helicopter design parameters and the motion state; The coupling module is used to couple the helicopter flight dynamics model with the wind speed distribution characteristics to obtain the helicopter flight dynamics model; The threat zone determination module is used to determine threat zones based on the wind speed distribution characteristics and the helicopter flight dynamics model. Specifically, it includes: determining a wind speed threat zone based on the environmental velocity field and turbulent kinetic energy distribution of the distribution characteristics; determining a spatial operation characteristic cloud map based on the control stick values ​​according to the helicopter flight dynamics model; determining a controllability threat zone based on the spatial operation characteristic cloud map and control stick margin threshold; determining a spatial attitude characteristic cloud map based on the helicopter attitude angle values ​​according to the helicopter flight dynamics model; determining an attitude threat zone based on the spatial attitude characteristic cloud map and attitude angle threshold; determining a spatial power characteristic cloud map based on the helicopter's required power according to the helicopter flight dynamics model; determining a power threat zone based on the spatial power characteristic cloud map and power threshold; determining a vortex ring limitation criterion based on the helicopter dynamics model using environmental wind speed, rotor induced velocity, and tail rotor induced velocity; and determining a vortex ring threat zone based on the vortex ring limitation criterion. The threat zone includes a wind speed threat zone, a controllability threat zone, an attitude threat zone, a power threat zone, and a vortex ring threat zone. The flight safety boundary determination module is used to merge the threat areas to determine the flight safety boundary.

7. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the helicopter flight safety boundary identification method according to any one of claims 1-5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the helicopter flight safety boundary identification method according to any one of claims 1-5.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the helicopter flight safety boundary identification method according to any one of claims 1-5.

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