Helicopter flight dynamics model

Abstract

The invention discloses a helicopter flight dynamics model which comprises an acting force determination and mass center motion equation, a helicopter rotation motion equation, a helicopter aerodynamic calculation equation, a numerical solution of the equations and a motion transformation equation of a related object. The model provides core data for the flight of the whole helicopter by establishing a helicopter centroid kinetic equation and a kinetic equation of rotation around the centroid, calculating aerodynamic characteristics of the helicopter, performing real-time numerical calculation on the helicopter kinetic equation, and determining parameters such as the position and attitude of the helicopter through motion relation calculation and coordinate transformation. According to the invention, the difficult problems of aerodynamic characteristics, operation stability characteristics, flight performance, various flight action control principles and the like of the rotor wing in the flight principle theory of the helicopter are well solved. And the theoretical teaching effect is greatly improved, the theoretical quality and training benefits of flight personnel are improved, the formation of fighting capacity is accelerated, and the military benefits are remarkable.

Description

Technical Field

[0001] The invention relates to a helicopter flight dynamics model and belongs to the field of helicopter teaching and flight training. Background Art

[0002] The helicopter flight principle course is an important professional course in the aviation theory teaching of helicopter flight students. The helicopter flight principle is based on the basic concepts, basic knowledge and basic theories of aerodynamics and flight dynamics, with the helicopter flight driving principle as the main content, and studies the helicopter aerodynamic performance characteristics, flight performance characteristics and flight control principles. The teaching effect of the helicopter flight principle course is closely related to the students' future flight ability, the quality of military flight training and flight safety.

[0003] The course content of helicopter flight principles includes the aerodynamic characteristics of the rotor, stability characteristics, flight performance, and the control principles of various flight actions. The course content is systematic, the theory is abstract, and the difficulty is relatively high, which is difficult for beginners to master.

[0004] Therefore, in order to better solve the above-mentioned teaching problems, it is urgent to design a helicopter flight dynamics model that can improve the teaching effect and enable students to experience flight and perceive theory. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies of the above-mentioned prior art and provide a helicopter flight dynamics model. The model establishes the helicopter center of mass motion equation and the rotational dynamics equation around the center of mass, calculates the aerodynamic characteristics of the helicopter, performs real-time numerical solution to the helicopter dynamics equation, determines the position, attitude and other parameters of the helicopter through motion relationship solution and coordinate transformation, and provides core data for the entire helicopter flight. For abnormal flight conditions such as vortex ring and rotor stall, the trajectory and attitude data are fitted and calculated by referring to the actual flight curve.

[0006] To achieve the above object, the present invention provides the following technical solution: a helicopter flight dynamics model, comprising:

[0007] Determination of forces and equations of motion for the center of mass;

[0008] The rotational motion equations of a helicopter;

[0009] Helicopter aerodynamic equations;

[0010] Numerical solutions of the above equations and the transformation equations of motion of the associated objects.

[0011] By establishing the determination equation of the helicopter's force and the equation of motion of the center of mass, the aerodynamic force of the fuselage can be calculated directly on the fuselage axis. The helicopter's attitude change is relatively small, and the vertical and lateral speeds are relatively small. According to the aerodynamic principle, the square of the speed of different fuselage axes can be used as a parameter to fit the aerodynamic force of the three axes, and the velocity component on the fuselage axis system can be obtained. The velocity relative to the ground axis system can be obtained by the coordinate transformation of the fuselage axis system and the ground axis system, and the position of the helicopter's center of mass relative to the ground axis system can be obtained by further integration.

[0012] By using the helicopter's rotational motion equation and according to the actual position of the rod, the target pitch angle and slope of the helicopter are set, and then the pitch angle acceleration and roll angle acceleration are determined according to the difference between the target pitch angle and slope and the actual pitch angle and slope, and the pitch angle velocity and roll angle velocity are obtained by integration, so that the actual pitch angle and slope are close to the target pitch angle and slope;

[0013] Through the helicopter aerodynamic calculation equation, after using the helicopter's rotational motion equation to obtain the helicopter's angle of attack, sideslip angle and speed, its aerodynamic force and torque can be determined according to the helicopter's air characteristics; through the numerical solution of the dynamic equation, the helicopter's aerodynamic characteristics are calculated, and the helicopter's dynamic characteristics are numerically solved in real time. The helicopter's position, attitude and other parameters are determined through motion relationship solution and coordinate transformation, providing core data for the entire helicopter flight.

[0014] Preferably, the process of determining the force and the center of mass motion equation is as follows:

[0015] The engine output power is the power source of the helicopter, and the power is given by the function: P = f(δ p ,V,h) is determined, where δ P , V, and h represent the helicopter's pitch lever position, speed, and altitude, respectively. The engine's output power generally has a delay of a few seconds as the parameters change. When designing the program, you can first set a target power P t =f(δ p ,V,h), and then use a power variable to approximate the target power according to the delay characteristics. The rotor force is given by the function: F = (P , V,h,V z ,δ r ) is determined, where P, V, h, V z , δ rThey represent power, helicopter speed, altitude, normal speed of the vertical body axis and the amount of rudder respectively. The rotor force is closely related to the engine power. First, the function of power and rotor force is simulated according to the engine technical curve, and then the speed, altitude, normal speed of the vertical body axis and the amount of rudder are used for correction. As the altitude increases, the rotor thrust at the same power gradually decreases. As the forward flight speed of the helicopter increases, the rotor thrust increases significantly due to the increase in the amount of air intake on the rotor rotating surface. The vertical normal speed also has a certain effect on the rotor thrust. As the vertical normal speed increases, the rotor thrust decreases due to the decrease in the angle of attack of the rotor blades. The amount of rudder will cause a change in the distribution of total power between the tail rotor and the rotor, so it will also cause a change in the rotor thrust. The front-to-back and left-to-right directions of the rotor force relative to the body axis system are basically consistent with the direction of the rotor rotation axis, and the direction of the rotor rotation axis is controlled by the joystick during flight. Therefore, the front-to-back and left-to-right positions of the joystick can be used to simulate the direction of the rotor thrust. In actual flight control, the pilot changes the blade angle of the rotor in different directions by using the joystick, and changes the direction of the rotor thrust by flapping the blades. The rotor force is decomposed to the body axis, and the tail rotor force is given by the function: F wj =(P,δ r ,V,h), where the tail rotor force acts on the horizontal axis of the fuselage axis to balance the reaction torque of the rotor and to control the helicopter laterally. Its magnitude depends mainly on the amount of rudder pedaling and engine output power, and is also related to the flight speed and altitude. The aerodynamic force of the fuselage can be calculated directly on the fuselage axis. The attitude change of the helicopter is relatively small, and the vertical and lateral speeds are relatively small. According to the aerodynamic principle, the square of the speed of different fuselage axes can be used as a parameter to fit the aerodynamic force of the three axes. Decompose the various forces on the helicopter along the fuselage axis and establish the motion equation:

[0016]

[0017] V in the equation x 、V y 、V z ,ω x ,ω y ,ω z , F x 、F y 、F z Represent the helicopter speed, angular velocity and the force components on the body axis. The integration gives the velocity component on the body axis system. The velocity relative to the ground axis system can be obtained by coordinate transformation between the body axis system and the ground axis system. Further integration gives the position of the helicopter's center of mass relative to the ground axis system.

[0018] Preferably, the rotational motion equation of the helicopter is as follows:

[0019] The pitch and lateral rotation of the helicopter are relatively gentle. In actual flight control, the pitch and lateral rotation of the helicopter are controlled by moving the joystick forward and backward, left and right to control the rotor thrust. According to the actual position of the joystick, the target pitch angle and slope of the helicopter are set, and then the pitch acceleration and roll acceleration are determined according to the difference between the target pitch angle and slope and the actual pitch angle and slope. The pitch velocity and roll velocity are obtained by integration, so that the actual pitch angle and slope are close to the target pitch angle and slope. The helicopter has a large deflection range and a large deflection velocity. Its movement is given by the equation: Description, where I z , Represent the helicopter's moment of inertia, angular acceleration, and rotor reaction torque M 反 Mainly determined by the engine power; tail rotor control torque M 操 Mainly determined by engine power and pedal position; deflection damping moment M 阻尼 Related to the deflection angular velocity; directional stabilizing torque M 安定 After obtaining the angular velocity around each body axis, the following formula can be used to obtain the rate of change of the helicopter's slope, pitch angle, and yaw angle:

[0020]

[0021] By integration, we can get the helicopter pitch angle, bank angle, and yaw angle.

[0022] Preferably, the aerodynamic calculation equation process of the helicopter is as follows:

[0023] To solve the equation of motion of a helicopter, the aerodynamic force and aerodynamic torque acting on the helicopter must be determined. The aerodynamic force includes the rotor pull and drag. The aerodynamic torque includes the control torque and stabilizing torque decomposed to each body axis. According to the basic principles of helicopter aerodynamics, the aerodynamic force and torque on the helicopter are related to the airflow angle and speed of the helicopter. According to the definition of the helicopter angle of attack and sideslip angle, the angle of attack and sideslip angle can be obtained by the following formula:

[0024]

[0025] The flight speed is given by: We get: xt 、v yt 、v zt They represent the total velocity of the helicopter in the airflow coordinate system and the component velocities of the helicopter in three directions in the body coordinate system. After obtaining the angle of attack, sideslip angle and speed of the helicopter, its aerodynamic force and torque can be determined according to the air characteristics of the helicopter.

[0026] Numerical solutions of the above equations and the transformation equations of motion of the associated objects.

[0027] Preferably, the numerical solution process is as follows:

[0028] In the determination of the forces and the equation of motion of the center of mass, the equation of motion of the helicopter's rotation, and the equation of aerodynamics of the helicopter, the pitch lever, throttle lever, pedals, etc. are known input parameters for the pilot's manipulation. These equations are closed when combined and can be solved. In order to obtain the motion of the helicopter, these differential equations are solved numerically.

[0029] The equations of motion of a helicopter can generally be summarized as the following set of first-order ordinary differential equations:

[0030]

[0031] The numerical solution of the differential equation adopts a one-step method, according to x k The differential value of this point To determine the value x of the next point k+1 .

[0032] Preferably, the helicopter engine output power is given by the function: P = f(δ p ,V,h) is determined, where δ P , V, and h represent the position of the helicopter's pitch lever, speed, and altitude respectively. The output power of the engine is mainly determined by the position of the pitch lever. With the change of flight speed, the power will also change a little. Altitude also has a certain influence on the power. Generally speaking, as the altitude increases, the power will decrease. First, the function of power and pitch lever can be fitted according to the engine technical curve, and then the function can be corrected by speed and altitude.

[0033] Preferably, the helicopter flight dynamics model adopts the direct use of the position of the joystick to determine the pull direction of the rotor and the pitch angle and slope of the helicopter. The dynamic mathematical models of different helicopter rotors are very complex, and the direct use of the position of the joystick to determine the pull direction of the rotor can greatly simplify the model. The pitch and roll changes of the helicopter are gentle and small, and the pitch angle and slope can be directly determined by the position of the joystick. The biggest feature of this algorithm is that it does not require complete aerodynamic data or data from the control system, and regards the helicopter as a general helicopter with only a rod and rudder input and position and attitude output. During the model debugging process, adjustments are made based on the difference between the pilot's flight situation and the actual situation.

[0034] Preferably, the helicopter flight dynamics model solves the motion problem of the associated object by using coordinate transformation. The motion analysis of the object is inseparable from the coordinate system. The most commonly used ground coordinate system is used here. replace, The origin is selected at a certain point on the ground, usually at the initial position of the object's movement; the z axis g is vertically downward; axis x g In the horizontal plane, its direction can be chosen arbitrarily, usually according to the convenience of describing the movement of the object; axis y g Point to x using the right-hand rule g The main function of the ground coordinate system is to measure the position and posture of an object. The definition of the coordinate system in the visual simulation is similar to that of the ground coordinate system. In order for an object to be displayed correctly in the visual simulation, its position and posture relative to the ground coordinate system (inertial coordinate system) must be determined. It is fixedly connected to the object. The origin is at the center of mass of the object; the longitudinal axis is along the structural longitudinal axis of the object, pointing forward; the vertical axis is generally in the symmetry plane of the object, perpendicular to the longitudinal axis, pointing downward; the transverse axis is perpendicular to the symmetry plane and points to the right. With ground coordinate system The relationship between is determined by three Euler angles or attitude angles (φ, θ, ψ). φ, θ, ψ are called roll angle, pitch angle and yaw angle respectively, and their value range is:

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. This model effectively avoids the divergence problem in helicopter dynamics calculation and debugging, as well as the comprehensive and high-precision requirements of helicopter aerodynamic parameters in traditional helicopter flight dynamics model calculation. It makes full use of the characteristics of our unit's diverse models and rich flight experience, and repeatedly adjusts the model to effectively solve the difficult problems in the theory of helicopter flight principles, such as the aerodynamic characteristics of the rotor, the stability characteristics, flight performance, and the control principles of various flight actions. It improves the learning environment of students' helicopter aviation theory courses and combines them more closely with actual flights.

[0037] 2. This model plays a great auxiliary role in teaching flight principles. When students conduct simulated flights, the theory of flight principles is displayed to students through visuals, instruments, curves and other forms, which can help flight students to more deeply understand and master the basic principles of flight principles and improve learning effects. On the instructor's console and the large screen on the side, the magnitude of various forces and moments on the three axes of the helicopter are displayed in the form of arrow graphics; various parameters of the helicopter are displayed in the form of a certain time curve, including the time history of aerodynamic angles, control amounts, helicopter trajectory parameters, etc., so that students can fully experience the dynamic stability and dynamic maneuverability of the helicopter. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In the attached picture:

[0039] Figure 1 A schematic diagram of the structure of a helicopter flight dynamics model of the present invention;

[0040] Figure 2 It is a schematic diagram of the automatic flight simulation of a helicopter of the present invention;

[0041] Figure 3 The aerodynamic angle and speed calculation block diagram of the present invention;

[0042] Figure 4 It is a schematic diagram of the body coordinate system structure of the present invention;

[0043] Figure 5 It is a schematic diagram of the structure of the body coordinate system and the ground coordinate system of the present invention. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present invention will be described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0045] Example:

[0046] Depend on Figure 1-5 The present invention relates to a helicopter flight dynamics model, including the determination of the acting force and the center of mass motion equation, the helicopter rotation motion equation, the helicopter aerodynamic calculation equation, the numerical solution of the dynamic equation and the motion transformation equation of the associated objects. By establishing the helicopter center of mass dynamics equation and the rotational dynamics equation around the center of mass, the aerodynamic characteristics of the helicopter are calculated, the helicopter dynamics equation is numerically solved in real time, and the position, attitude and other parameters of the helicopter are determined by the motion relationship solution and coordinate transformation, providing core data for the entire helicopter flight. The helicopter engine output power is given by the function: P = f(δ p ,V,h). The helicopter rotor force is determined by the function: F = (P,V,h,V z ,δ r ) is determined. The helicopter motion equation is: The model algorithm directly uses the position of the joystick to determine the direction of the rotor's pulling force and the helicopter's pitch angle and slope. The helicopter flight dynamics model realizes a full range of multi-perspective dynamic display of flight principle-related parameters during flight. For abnormal flight conditions such as vortex rings and rotor stall, the helicopter flight dynamics model uses actual flight curves to perform fitting calculations on trajectory and attitude data. The helicopter flight dynamics model solves the motion problem of related objects by using coordinate transformation;

[0047] Using P = f(δ p,V,h) to determine the acting force and solve the center of mass motion. The output power of the engine is mainly determined by the position of the pitch rod. As the flight speed changes, the power will also change slightly. The altitude also has a certain impact on the power. Generally speaking, as the altitude increases, the power will decrease. First, the function of power and pitch rod can be fitted according to the engine technical curve, and then the function can be corrected by speed and altitude.

[0048] Using F=(P,V,h,V z ,δ r ) determines the size of the rotor force. The rotor force is closely related to the engine power. First, the function of power and rotor force can be fitted according to the engine technical curve, and then the speed, altitude, normal speed of the vertical body axis and the amount of rudder pedal are used for correction. In actual flight control, the pilot changes the blade angle of the rotor in different directions through the control stick, and changes the direction of the rotor pull through the flapping of the blades. Therefore, the followability of different helicopter rotors to the stick must be considered in the fitting.

[0049] The rotor force is decomposed into the fuselage axis, and the fuselage aerodynamic force can be calculated directly on the fuselage axis. The helicopter's attitude change is relatively small, and the vertical and lateral speeds are relatively small. According to the aerodynamic principles, the square of the speed of different fuselage axes can be used as parameters to fit the aerodynamic forces of the three axes.

[0050] Decompose the various forces acting on the helicopter along the body axis and establish the following motion equation:

[0051]

[0052] V in the equation x 、V y 、V z ,ω x ,ω y ,ω z , F x 、F y 、F z Represent the helicopter speed, angular velocity and the force components on the body axis. The integration gives the velocity component on the body axis system. The velocity relative to the ground axis system can be obtained by coordinate transformation between the body axis system and the ground axis system. Further integration gives the position of the helicopter's center of mass relative to the ground axis system.

[0053] The pitch and roll of the helicopter are relatively gentle. In actual flight control, the pitch and roll of the helicopter are controlled by moving the joystick forward and backward, left and right to control the rotor thrust. According to the actual position of the joystick, the target pitch angle and slope of the helicopter are set, and then the pitch acceleration and roll acceleration are determined according to the difference between the target pitch angle and slope and the actual pitch angle and slope. The pitch velocity and roll velocity are obtained by integration, so that the actual pitch angle and slope are close to the target pitch angle and slope.

[0054] The helicopter has a large deflection range and a large deflection angular velocity. According to the equation of motion: After obtaining the angular velocity around each body axis, the following formula can be used to obtain the rate of change of the helicopter's slope, pitch angle, and yaw angle:

[0055]

[0056] By integration, we can get the helicopter's slope, pitch angle, and yaw angle.

[0057] For the flight of constant altitude, constant speed and constant heading controlled by the helicopter autopilot, a negative feedback with adjustable gain can be superimposed on the throttle pitch lever, the longitudinal control of the joystick and the pedal input. By adjusting the gain value of the negative feedback, the automatic flight of the helicopter can be simulated, such as Figure 2 shown.

[0058] To solve the helicopter's motion equation, the aerodynamic force and aerodynamic torque acting on the helicopter must also be determined. The aerodynamic force includes the rotor pull and drag; the aerodynamic torque includes the control torque and stabilizing torque decomposed to each body axis. According to the basic principles of helicopter aerodynamics, the aerodynamic force and torque on the helicopter are related to the helicopter's airflow angle and speed. The angle of attack, sideslip angle and speed are given by Figure 3 calculate.

[0059] According to the definition of helicopter angle of attack and sideslip angle, the angle of attack and sideslip angle can be obtained by the following formula:

[0060]

[0061] The flight speed is obtained by the following formula:

[0062]

[0063] After obtaining the helicopter's angle of attack, sideslip angle and speed, its aerodynamic force and torque can be determined according to the helicopter's air characteristics.

[0064] In the above equations, the pitch lever, throttle lever, pedals, etc. are known pilot control input parameters. It can be seen that, in addition to the above known pilot control input variables, all variables on the left side of the block appear on the right side of the block, which shows that these equations are closed and can be solved. In order to obtain the movement of the helicopter, these differential equations must be solved numerically.

[0065] The equations of motion for a helicopter can be summarized as the following set of first-order ordinary differential equations:

[0066]

[0067] The numerical solution of the differential equation adopts a one-step method, according to x k The differential value of this point To determine the value x of the next point k+1 .

[0068]

[0069] In order to keep synchronization with the virtual scene, the calculation step dt is taken as the time length between two frames of the scene.

[0070] As for the motion problem of associated objects in the scene, in scene simulation, we often encounter such a situation that object A is attached to object B, and sometimes we need to control the relative motion of object A on object B. Then, when the motion of object B and the motion of object A relative to object B are known, we need to determine the position and posture of object A in the absolute coordinate system for correct display, and solve this problem through coordinate transformation.

[0071] The transformation matrix from the ground coordinate system to the body coordinate system is as follows:

[0072]

[0073] Then the description of a space vector in the ground coordinate system and the description in the body coordinate system have the following relationship:

[0074] R t =L(φ,θ,ψ)R g

[0075] Also available:

[0076] R g =(L(φ,θ,ψ)) -1 R t

[0077] That is, the transformation matrix from the body coordinate system to the ground coordinate system is (L(φ,θ,ψ)) -1 Next, we determine the position and attitude of object A relative to the ground coordinate system. Figure 4 , Figure 5 shown.

[0078] Assume that the position of object B relative to the ground coordinate system is R bg =[x bg ,y bg 、z bg ]T, the attitude angles are φ bg ,θ bg , bg , the position of object A relative to the coordinate system of object B is R ab =[x ab ,y ab 、z ab ]T, the attitude angles are φ ab ,θ ab , ab . By R g =(L(φ,θ,ψ)) -1 R t , the position of object A relative to the ground coordinate system is:

[0079] R ag =R bg +(L bg (φ bg ,θ bg ,ψ bg )) -1 R ab

[0080] Where L bg (φ bg ,θ bg ,ψ bg ) is the transformation matrix from the ground system to the B body coordinate system

[0081] Determine the attitude angle φ of object A relative to the ground coordinate system ag ,θ ag , ag The transformation matrix between the ground coordinate system and the object A body coordinate system is L ag (φ ag ,θ ag ,ψ ag ). The transformation matrix between the ground coordinate system and the object B body coordinate system is L bg (φ bg ,θ bg ,ψ bg ), the transformation matrix between the coordinate system of object B and the coordinate system of object A is L ab (φ ab ,θ ab ,ψ ab ). Then we have:

[0082] Lag (φ ag ,θ ag ,ψ ag )=L ab (φ ab ,θ ab ,ψ ab )L bg (φ bg ,θ bg ,ψ bg )

[0083] When the posture of object B and the posture of object A relative to object B are known, the right side of the above equation is determined. Let the matrix on the right side of the equation be as follows:

[0084]

[0085] The corresponding entries of the matrices are equal and are given by:

[0086]

[0087] Depend on:

[0088] -sinθ ag = l 13

[0089] have:

[0090]

[0091] Depend on:

[0092]

[0093] have:

[0094]

[0095] Depend on:

[0096]

[0097] have:

[0098]

[0099] In this way, when the movement of object B and the movement of object A relative to object B are known, the position and posture of object A in the inertial coordinate system are determined.

[0100] After determining the spatial position of the helicopter (x d ,y d ,z d) and attitude parameters (φ, θ, ψ), according to the coordinate and angle definitions of the position and attitude of the visual system, after coordinate transformation, the movement changes of the helicopter can be displayed in the visual scene.

[0101] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A helicopter flight dynamics model, characterized in that include: Determination of forces and equations of motion for the center of mass; The rotational motion equations of a helicopter; Helicopter aerodynamic equations; Numerical solutions of the above equations and the transformation equations of motion of associated objects; By establishing the equations for determining the helicopter's forces and the equations for the motion of the center of mass, the aerodynamic force of the fuselage is directly calculated on the fuselage axis. The square of the velocity of the different fuselage axes is used as a parameter to fit the aerodynamic forces of the three axes, and the velocity component on the fuselage axis system is obtained. The velocity relative to the ground axis system is obtained through the coordinate transformation of the fuselage axis system and the ground axis system, and the position of the helicopter's center of mass relative to the ground axis system is further integrated. By using the helicopter's rotational motion equation and according to the actual position of the rod, the target pitch angle and slope of the helicopter are set, and then the pitch angle acceleration and roll angle acceleration are determined according to the difference between the target pitch angle and slope and the actual pitch angle and slope, and the pitch angle velocity and roll angle velocity are obtained by integration, so that the actual pitch angle and slope are close to the target pitch angle and slope; Through the helicopter aerodynamic calculation equation, after obtaining the helicopter's angle of attack, sideslip angle and speed using the helicopter's rotational motion equation, the aerodynamic force and torque are determined according to the helicopter's air characteristics; Through numerical solutions, the aerodynamic characteristics of the helicopter are calculated, and the helicopter's dynamic characteristics are numerically solved in real time. The position, attitude and other parameters of the helicopter are determined through motion relationship solution and coordinate transformation, providing core data for the entire helicopter flight.

2. A helicopter flight dynamics model according to claim 1, characterized in that The determination of the force and the center of mass motion equation are as follows: The engine output power is given by the function: P = f(δ p ,V,h) is determined, where δ P , V, and h represent the helicopter's pitch lever position, speed, and altitude, respectively. The engine's output power changes with the parameters with a delay of a few seconds. First, set a target power P t =f(δ p ,V,h), and then use a power variable to approximate the target power according to the delay characteristics; the rotor force is given by the function: F = (P,V,h,V z ,δ r ) is determined, where P, V, h, V z , δ r Respectively represent power, helicopter speed, altitude, normal speed of the vertical body axis and the amount of rudder pedal. First, the function of power and rotor force is simulated according to the engine technical curve, and then the speed, altitude, normal speed of the vertical body axis and the amount of rudder pedal are used for correction; the front and back, left and right positions of the joystick are used to simulate the direction of the rotor thrust. The pilot changes the blade angle of the rotor in different directions through the joystick, and changes the direction of the rotor thrust by waving the blades. The rotor force is decomposed to the body axis, and the tail rotor force is given by the function: F wj =(P,δ r , V, h), the tail rotor force acts on the horizontal axis of the fuselage axis to balance the reaction torque of the rotor and to control the helicopter laterally. The aerodynamic force of the fuselage is calculated directly on the fuselage axis. The square of the velocity of the different fuselage axes is used as a parameter to fit the aerodynamic forces of the three axes. The various forces on the helicopter are decomposed along the fuselage axis to establish the motion equation: V in the equation x 、V y 、V z ,ω x ,ω y ,ω z , F x 、F y 、F z They represent the helicopter speed, angular velocity and the component of the force on the fuselage axis respectively. The integration gives the velocity component on the fuselage axis system. The speed relative to the ground axis system can be obtained through coordinate transformation between the fuselage axis system and the ground axis system. Further integration gives the position of the helicopter's center of mass relative to the ground axis system.

3. A helicopter flight dynamics model according to claim 1, characterized in that The rotational motion equation of the helicopter is as follows: Set the target pitch angle and slope of the helicopter, and then determine the pitch acceleration and roll acceleration according to the difference between the target pitch angle and slope and the actual pitch angle and slope. Integrate to get the pitch velocity and roll velocity, so that the actual pitch angle and slope are close to the target pitch angle and slope. The helicopter has a large deflection range and a large deflection angular velocity. Its motion is given by the equation: Description, where I z , Represent the helicopter's moment of inertia, angular acceleration, and rotor reaction torque M 反 Determined by the engine power; tail rotor control torque M 操 Determined by engine power and pedal position; deflection damping moment M 阻尼 Related to the deflection angular velocity; directional stabilizing torque M 安定 Related to the sideslip angle, after obtaining the angular velocity around each body axis, the following formula can be used to obtain the rate of change of the helicopter's slope, pitch angle, and yaw angle: By integration, we can get the helicopter pitch angle, bank angle, and yaw angle.

4. A helicopter flight dynamics model according to claim 1, characterized in that The aerodynamic calculation equation process of the helicopter is as follows: The helicopter angle of attack and sideslip angle are obtained by the following formula: The flight speed is given by: We get: xt 、v yt 、v zt They represent the total velocity of the helicopter in the airflow coordinate system and the component velocities of the helicopter in three directions in the body coordinate system. After obtaining the angle of attack, sideslip angle and speed of the helicopter, its aerodynamic force and torque are determined according to the air characteristics of the helicopter.

5. A helicopter flight dynamics model according to claim 1, characterized in that The numerical solution process is as follows: The equations of motion for a helicopter are summarized as the following set of first-order ordinary differential equations: The numerical solution of the differential equation adopts a one-step method, according to x k and the differential value of this point To determine the value x of the next point k+1 .

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