A simulation method for tilt rotor dynamics based on multibody dynamics

Abstract

This invention discloses a tiltrotor dynamics simulation method based on multibody dynamics, belonging to the field of aircraft dynamics modeling and simulation technology. It constructs a modular system including an input module, an output module, a fuselage module, a propeller module, a coupling mechanism module, and a dynamics solution module. The fuselage module has six generalized coordinates. In the propeller module, each propeller is independently modeled as a rigid body. The coupling mechanism module models the active actuator hinge between the rotor and the fuselage through rigid connections. The Kane method is used to perform dynamic modeling of the system, forming the system's equations of motion by constructing partial velocity expressions and inertial force forms for each component. The equations of motion are then numerically integrated and solved using a solver in the Simulink environment. The advantages of this invention are: accurate description of gyrocoupling effects, support for rapid changes in multirotor configurations, provision of comprehensive component-level mechanical data output, and improved simulation fidelity and engineering application value.

Description

Technical Field

[0001] This invention relates to the field of aircraft dynamics modeling and simulation technology, specifically to a tilt rotor dynamics simulation method based on multibody dynamics. Background Technology

[0002] With the rapid development of urban air traffic and electric vertical takeoff and landing (eVTOL) aircraft, tiltrotor configurations, by tilting the rotor from a vertical to a horizontal state, achieve a smooth transition from hovering to cruise flight, thus balancing the vertical maneuverability of rotorcraft with the high-speed range capability of fixed-wing aircraft. Currently, the commonly used engineering approach is the 6-DOF rigid body model, based on Newton-Euler mechanics, suitable for describing the overall attitude and velocity changes of an aircraft. However, for multi-rotor tiltrotor configurations with complex coupled actuators, there is currently no publicly available engineering implementation of the eVTOL Kane method for tiltrotor modeling, especially lacking a modular modeling scheme for Simulink. This results in a lack of modular structure, making it unable to adapt to rapid changes in different configurations and the number of components, and also lacking the ability to output component-level mechanical data (such as hinge torque and motor load). Furthermore, insufficient handling of coupled gyroscopic effects limits the control law's responsiveness to nonlinear phenomena. Additionally, incomplete modeling of the non-inertial reference frame affects the physical accuracy and consistency of attitude calculations. Summary of the Invention

[0003] To address the aforementioned technical problems, a multibody dynamics-based tiltrotor dynamics simulation method is provided. This technical solution solves the problems mentioned in the background technology, such as the inability to accurately describe the gyroscopic coupling effect of tiltrotor aircraft during the rotor disk tilting process, the lack of modular structure and the ability to output component-level mechanical data, which limit the response capability of the control law to nonlinear phenomena and the practical application value of the simulation model.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for simulating tilt rotor dynamics based on multibody dynamics includes:

[0006] A modular system is constructed, comprising an input module, an output module, a fuselage module, a propeller module, a connecting mechanism module, and a dynamics solution module. The fuselage module has six generalized coordinates to describe the three-axis position and attitude angles of the main structure of the aircraft. In the propeller module, each propeller is independently modeled as a rigid body with two generalized coordinates: propeller rotation angle and propeller shaft tilt angle. The connecting mechanism module models the active motion hinge between the rotor and the fuselage through rigid connection. The dynamics solution module constructs the system dynamics equations based on the Kane method. The input module outputs the control variables from the received flight control law. The output module outputs the generalized velocity derivative, attitude data, motor drive torque, and tilt shaft load torque.

[0007] The Kane method is used to model the dynamics of the system. By constructing partial velocity expressions and inertial force forms for each component, the system's equations of motion are formed based on d'Alembert's principle.

[0008] The equations of motion are solved numerically using a solver in the Simulink environment.

[0009] Preferably, the modular system construction includes:

[0010] During the initialization phase, the structural topology, mass properties, inertia tensor, and initial state of all components are defined.

[0011] Coordinate settings are implemented by assigning generalized coordinates and velocity variables to each module and establishing coordinate transformation relationships.

[0012] Kinematic modeling is used, and vector analysis methods are employed to calculate the velocity and acceleration of each component, constructing partial velocity representations.

[0013] Dynamic modeling projects external forces, gravity, and inertial forces to various generalized directions to generate generalized force vectors;

[0014] Assemble the dynamic equations, calculate the difference between inertial force and external force, and generate the Kane equations by taking the dot product for each generalized velocity;

[0015] Solving and Integrating: Input the equations into the Simulink solver and iteratively update the system state;

[0016] Data output records the dynamic response variables of each component.

[0017] Preferably, the generalized coordinates of the body module are defined as three-axis position and attitude angles, and its mass properties and inertia tensor are set during the initialization phase. The attitude angles include roll φ, pitch θ, and yaw ψ.

[0018] Preferably, the rotational degree of freedom of the propeller module is driven and controlled by the corresponding motor, and the tilting degree of freedom is controlled by the corresponding servo motor. Its inertial tensor is used to automatically generate the cross product of the propeller's rotational angular velocity and tilting angular velocity to model the gyro coupling effect and reflect it in the body's roll and yaw responses.

[0019] Preferably, the connecting mechanism module is modeled through an active hinge, and explicitly outputs the force exerted by the propeller on the fuselage and the load torque of the tilt shaft.

[0020] Preferably, the output module provides data on the motor shaft driving torque, the tilting mechanism load torque, and the reaction force at the component connection points.

[0021] Preferably, the numerical stability measures employed in the numerical integration solution specifically include:

[0022] Set a limiter for the state variable to prevent the value from diverging;

[0023] Standardize some speed expressions;

[0024] Integrating using a highly stable ODE solver with a fixed step size.

[0025] Preferably, the scalability supported by the system architecture specifically includes:

[0026] Add any number of propeller modules without modifying the overall framework;

[0027] Suitable for symmetrical or asymmetrical configurations;

[0028] Integrate other rigid body modules and interface with existing control law modules.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention proposes a multibody dynamics-based simulation method for tilt rotor dynamics. By implementing the Kane method in a modular form within the Simulink environment, a system is constructed comprising an input module, an output module, a fuselage module, a propeller module, a coupling mechanism module, and a dynamics solution module. Each module is modeled independently with clearly defined generalized coordinates and degrees of freedom. This allows for the addition of any number of propeller modules without modifying the overall framework, adapting to symmetrical or asymmetrical configurations, integrating other rigid body modules, and interfacing with existing control law modules. It also accurately describes the gyroscopic coupling effect during rotor disk tilting, avoiding the problem of traditional 6-DOF models failing to accurately reflect roll or yaw coupling phenomena in control laws. Furthermore, it supports subsequent aircraft control law design, structural load analysis, actuator life assessment, and other engineering stages, enhancing the practical application value of the simulation model.

[0031] This invention proposes a multibody dynamics-based simulation method for tiltrotor dynamics. By enabling the explicit output of motor shaft driving torque, tilt mechanism load torque, and component connection point reaction force data in the system, and employing a series of numerical stability measures during the numerical integration process, this method supports structural life assessment and drive design. It provides comprehensive component-level mechanical data output capabilities. Furthermore, by setting a limiter, standardizing the process, and using a highly stable ODE solver, the method ensures high accuracy and stability in the simulation process, avoiding numerical divergence and error accumulation. It also provides high-precision simulation results, offering reliable technical support for aircraft design, control, and optimization, and enhancing the practical application value of the simulation model. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the process of the present invention;

[0033] Figure 2 This is a schematic diagram illustrating the process of constructing a modular system in this invention;

[0034] Figure 3 This is a flowchart illustrating the numerical stability measures employed in the numerical integration solution of this invention.

[0035] Figure 4 This is a flowchart illustrating the scalability supported by the system architecture in this invention. Detailed Implementation

[0036] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0037] Reference Figure 1 As shown, a tilt rotor dynamics simulation method based on multibody dynamics includes:

[0038] A modular system is constructed, comprising an input module, an output module, a fuselage module, a propeller module, a connecting mechanism module, and a dynamics solution module. The fuselage module has six generalized coordinates to describe the three-axis position and attitude angles of the main structure of the aircraft. In the propeller module, each propeller is independently modeled as a rigid body with two generalized coordinates: propeller rotation angle and propeller shaft tilt angle. The connecting mechanism module models the active motion hinge between the rotor and the fuselage through rigid connection. The dynamics solution module constructs the system dynamics equations based on the Kane method. The input module outputs the control variables from the received flight control law. The output module outputs the generalized velocity derivative, attitude data, motor drive torque, and tilt shaft load torque.

[0039] The Kane method is used to model the dynamics of the system. By constructing partial velocity expressions and inertial force forms for each component, the system's equations of motion are formed based on d'Alembert's principle.

[0040] The equations of motion are solved numerically using a solver in the Simulink environment.

[0041] First, during the initialization phase, the structural topology, mass properties, inertia tensor, and initial state of all components are defined. Then, generalized coordinates and velocity variables are assigned to each module, and coordinate transformation relationships are constructed. Next, the velocity and acceleration of each component are calculated using vector analysis methods, and partial velocity expressions are constructed. External forces, gravity, and inertial forces are projected onto each generalized direction to generate generalized force vectors. Then, according to the Kane method, the difference between inertial forces and external forces is calculated. The dot product of each generalized velocity is used to generate the Kane equations. The equations are input into the Simulink solver to iteratively update the system state. Finally, the dynamic response variables of each component are recorded. In the numerical integration process, measures such as setting limiters for state variables, standardizing some velocity expressions, using a highly stable ODE solver with a fixed step size are employed to ensure numerical stability. This allows for modular system construction, supporting the addition of any number of propeller modules without modifying the overall framework, adapting to symmetrical or asymmetric configurations, integrating other rigid body modules, and interfacing with existing control law modules, significantly improving the system's scalability and adaptability. Furthermore, the use of the Kane method for dynamic modeling accurately describes the gyroscopic coupling effect during propeller disk tilting, avoiding the limitations of traditional 6-DOF models in terms of control law... The problem of not being able to accurately reflect roll or yaw coupling phenomena is addressed by explicitly outputting the motor shaft drive torque and tilt shaft load torque, supporting structural life assessment and drive design, providing comprehensive component-level mechanical data output capabilities, and efficiently solving in the Simulink environment. This supports multiple engineering stages such as subsequent aircraft control law design, structural load analysis, and actuator life assessment, enhancing the practical application value of the simulation model. Thus, a modular system including input module, output module, airframe module, propeller module, connecting mechanism module, and dynamics solution module is constructed, realizing high-fidelity dynamics simulation of tiltrotor aircraft.

[0042] Reference Figure 2 As shown, the modular system construction includes:

[0043] During the initialization phase, the structural topology, mass properties, inertia tensor, and initial state of all components are defined.

[0044] Coordinate settings are implemented by assigning generalized coordinates and velocity variables to each module and establishing coordinate transformation relationships.

[0045] Kinematic modeling is used, and vector analysis methods are employed to calculate the velocity and acceleration of each component, constructing partial velocity representations.

[0046] Dynamic modeling projects external forces, gravity, and inertial forces to various generalized directions to generate generalized force vectors;

[0047] Assemble the dynamic equations, calculate the difference between inertial force and external force, and generate the Kane equations by taking the dot product for each generalized velocity;

[0048] Solving and Integrating: Input the equations into the Simulink solver and iteratively update the system state;

[0049] Data output records the dynamic response variables of each component.

[0050] During the initialization phase, the system defines the structural topology, mass properties, inertia tensor, and initial state of all components, providing basic data support for subsequent modeling, ensuring that simulation errors caused by inaccurate parameters are eliminated, and improving the physical accuracy of the model. Next, in the coordinate setting phase, generalized coordinates and velocity variables are assigned to each module, and coordinate transformation relationships are constructed so that the motion state of each component can be described and analyzed in a unified coordinate system.

[0051] In the kinematic modeling stage, vector analysis methods are used to calculate the velocity and acceleration of each component and construct partial velocity expressions, providing the necessary kinematic foundation for dynamic modeling.

[0052] During the dynamic modeling phase, the system projects external forces, gravity, and inertial forces to various generalized directions to generate generalized force vectors, ensuring that all forces acting on the aircraft can be accurately considered and calculated.

[0053] In the dynamic equation assembly stage, the difference between inertial force and external force is calculated, and the Kane equations are generated by taking the dot product of each generalized velocity. This allows for the efficient construction of the system's dynamic equations based on the Kane method. In the solution and integration stage, the equations are input into the Simulink solver, and the system state is updated iteratively, enabling numerical simulation of the aircraft's dynamic behavior.

[0054] The data output stage records the dynamic response variables of each component, providing detailed data support for subsequent analysis and design.

[0055] The generalized coordinates of the body module are defined as three-axis position and attitude angles. Its mass properties and inertia tensor are set during the initialization phase. The attitude angles include roll φ, pitch θ, and yaw ψ.

[0056] The generalized coordinates of the airframe module are defined as three-axis position and attitude angles. The three-axis position includes position coordinates in the x, y, and z directions, while the attitude angles include roll angle φ, pitch angle θ, and yaw angle ψ. This allows the airframe module to comprehensively describe the aircraft's position and attitude changes in space, providing a foundation for subsequent dynamic modeling. Simultaneously, during the initialization phase, the system's mass properties and inertia tensor are set. These parameters are key factors describing the aircraft's dynamic characteristics and directly affect its response characteristics under different motion states.

[0057] During the construction process, the initial position and attitude angles in the three axes must first be determined based on the actual physical characteristics of the aircraft. These initial conditions provide a starting point for subsequent simulations. Next, the mass properties and inertia tensor are set based on the actual mass and distribution of the aircraft; the accuracy of these parameters directly affects the accuracy of the dynamic model. This ensures that the airframe modules can accurately reflect the aircraft's motion in space, including translational and rotational motions.

[0058] During implementation, the generalized coordinates and physical properties of the body module are integrated into the overall dynamics simulation system, interacting with other modules such as the propeller module and the coupling mechanism module. This enables the body module not only to describe its own motion state but also to work collaboratively with other modules to simulate the overall dynamics of the aircraft.

[0059] The generalized coordinate definition method for the airframe module, by introducing the definitions of three-axis position and attitude angles, can more comprehensively describe the motion state of the aircraft, avoiding the problem of incomplete description that may exist in traditional methods. Secondly, the precise setting of mass properties and inertia tensors allows the dynamic model to more accurately reflect the actual physical characteristics of the aircraft, improving the accuracy and reliability of the simulation. These improvements enable the method of this invention to provide higher simulation accuracy and better engineering application value when dealing with complex tiltrotor aircraft dynamics problems.

[0060] The propeller module's rotational degree of freedom is driven and controlled by the corresponding motor, and its tilting degree of freedom is controlled by the corresponding servo motor. Its inertial tensor is used to automatically generate the cross product of the propeller's rotational angular velocity and tilting angular velocity to model the gyro coupling effect and reflect it in the aircraft's roll and yaw responses.

[0061] When a propeller tilts, its rotational inertia generates a gyroscopic effect around the tilt axis. This effect directly affects the attitude change of the aircraft, thus more realistically reflecting the impact of propeller motion on the overall dynamic behavior of the aircraft. In modeling the gyroscopic coupling effect, by calculating the cross product of angular velocities, the gyroscopic torque generated by the propeller during high-speed rotation and tilting can be accurately simulated. This torque has a significant impact on the roll and yaw responses of the aircraft.

[0062] The propeller's rotation is controlled by a motor through precise speed control, while its tilt is controlled by a servo motor through angle control. This independent control not only improves system flexibility but also allows for precise modeling and simulation of the motion state of each propeller. During operation, the independently controlled rotation and tilt degrees of freedom enable accurate modeling of each propeller's motion, avoiding the simplification or neglect of certain degrees of freedom that may occur in traditional methods. Furthermore, the automatic generation of gyrocoscopic coupling effects using inertial tensors more realistically reflects the impact of propeller motion on the aircraft's attitude, improving the accuracy and reliability of the simulation model. This helps engineers more accurately predict and evaluate the aircraft's dynamic behavior under different flight conditions, thereby improving the aircraft's performance and safety.

[0063] The connection mechanism module is modeled through an active hinge, and explicitly outputs the force exerted by the propeller on the fuselage and the load torque of the tilt shaft.

[0064] The connection mechanism module models the active actuator hinge between the rotor and the fuselage using a rigid connection. It explicitly outputs the forces exerted by the propeller on the fuselage and the tilt shaft load torque, providing more accurate and comprehensive data support for aircraft dynamics simulation. During its construction, the connection points and connection methods between the rotor and the fuselage must first be defined. By assuming a rigid connection, the module simplifies complex flexible connection problems, making the modeling process more intuitive and easier to handle. Next, the module calculates the forces exerted by the propeller on the fuselage based on the propeller's motion. These forces include thrust and torque, directly affecting the fuselage's motion. Simultaneously, the module calculates the tilt shaft load torque, generated by the propeller's tilting motion, which directly affects the tilt shaft load. This allows for a more accurate capture of the interaction between the propeller and the fuselage, avoiding the simplification or neglect of certain key factors that may occur in traditional methods.

[0065] This allows the mechanism module to update the force exerted by the propeller on the fuselage and the load torque on the tilt shaft in real time through the calculation of dynamic equations, reflecting the influence of propeller motion on the fuselage in real time, making the simulation results more realistic and reliable, and providing more accurate data support for the dynamic simulation of aircraft.

[0066] The output module provides data on motor shaft driving torque, tilting mechanism load torque, and component connection point reaction force.

[0067] The output module is tightly integrated with other modules in the system, such as the body module, propeller module, and coupling mechanism module. The body and propeller modules use kinematic and dynamic modeling to calculate the motion and force conditions of each component. The coupling mechanism module uses rigid connection modeling to calculate the force exerted by the propeller on the body and the load torque on the tilt shaft. This data is then transmitted to the output module for aggregation and processing, enabling the output module to provide data on the motor shaft drive torque, tilt mechanism load torque, and reaction forces at component connection points.

[0068] During actual use, the output module first receives relevant mechanical data from various modules, including motor shaft drive torque, tilt mechanism load torque, and component connection point reaction forces. The output module then organizes and formats this data for subsequent analysis and use. The output module also features data recording and storage capabilities, recording dynamic response variables generated during simulation for use in subsequent control law adjustments and structural design analyses. Furthermore, the output module's data output boasts high precision and real-time performance, accurately reflecting the aircraft's mechanical response under various flight conditions, providing reliable data support for engineering design. In addition, the output module's design exhibits excellent scalability and compatibility, allowing for easy integration with other systems and tools, further enhancing its value in engineering applications.

[0069] Reference Figure 3 As shown, the numerical stability measures employed in the numerical integration solution specifically include:

[0070] Set a limiter for the state variable to prevent the value from diverging;

[0071] Standardize some speed expressions;

[0072] Integrating using a highly stable ODE solver with a fixed step size.

[0073] First, by limiting the range of state variables during simulation, excessively large or small variable values ​​due to the accumulation of numerical errors can be avoided, thus preventing distortion and divergence in simulation results. This completes the step of setting a limiter for the state variables to prevent numerical divergence. The limiter setting effectively improves the robustness of the simulation, avoiding numerical divergence and error accumulation problems. This is particularly significant when dealing with strongly nonlinear systems and fast dynamic responses, significantly improving simulation stability.

[0074] Secondly, by normalizing some velocity expressions, rounding errors and cumulative errors in numerical calculations are reduced, thereby improving the accuracy and stability of numerical calculations. This achieves the effect of standardizing some velocity expressions, making them more suitable for systems with high dynamic range and high frequency changes, and effectively avoiding simulation result deviations caused by numerical errors.

[0075] Finally, a highly stable ODE solver with a fixed step size is used for integration. Highly stable ODE solvers (such as ode15s) perform excellently when dealing with rigid systems, effectively handling the strong rigidity and rapidly changing dynamic characteristics of such systems. Configuring a fixed step size for integration further improves the stability and accuracy of the numerical calculation, avoiding the accumulation of numerical errors caused by variable step sizes. This allows the simulation process to obtain high-precision simulation results while maintaining computational efficiency.

[0076] The combined application of the above measures enables the present invention to provide high-precision and high-stability simulation results in the dynamic simulation of tiltrotor aircraft, providing reliable technical support for the design, control and optimization of aircraft.

[0077] Reference Figure 4 As shown, the scalability supported by the system architecture specifically includes:

[0078] Add any number of propeller modules without modifying the overall framework;

[0079] Suitable for symmetrical or asymmetrical configurations;

[0080] Integrate other rigid body modules and interface with existing control law modules.

[0081] First, any number of propeller modules can be added without modifying the overall framework. This allows the system to flexibly adapt to different propeller configuration requirements; adding or removing propellers does not require changes to the overall system architecture. This greatly improves the system's adaptability and flexibility, enabling it to easily meet various aircraft design needs.

[0082] Secondly, the system architecture can adapt to both symmetrical and asymmetrical configurations. Whether it's a traditional symmetrical configuration or a more complex asymmetrical configuration, the system can be adapted through modular design. This allows the system to be applied to various types of tiltrotor aircraft, meeting diverse design requirements. It provides greater design freedom without sacrificing performance.

[0083] Furthermore, the system architecture supports the integration of other rigid body modules and can interface with existing control law modules. This allows the system to handle not only the dynamics simulation of the rotor and airframe but also to extend to the simulation of other rigid body modules, such as suspension arms and payload bays. Through interface with the control law module, seamless integration from dynamics simulation to control law design can be achieved, providing comprehensive support for the overall design and optimization of the aircraft.

[0084] Furthermore, the modular design isolates each functional module, allowing for independent development, testing, and integration of each. This not only improves system development efficiency but also reduces maintenance costs. During implementation, standardized interfaces and data interaction methods ensure efficient collaboration between modules.

[0085] In summary, the advantages of this invention are: by constructing partial velocity expressions and inertial force forms for each component, and forming the system motion equations based on d'Alembert's principle, it can achieve efficient solution in the Simulink environment, supporting multiple engineering stages such as subsequent aircraft control law design, structural load analysis, and actuator life assessment.

[0086] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for simulating the dynamics of a tilting rotor based on multibody dynamics, characterized in that, include: A modular system is constructed, comprising an input module, an output module, a fuselage module, a propeller module, a connecting mechanism module, and a dynamics solution module. The fuselage module has six generalized coordinates to describe the three-axis position and attitude angles of the main structure of the aircraft. In the propeller module, each propeller is independently modeled as a rigid body with two generalized coordinates: propeller rotation angle and propeller shaft tilt angle. The connecting mechanism module models the active motion hinge between the rotor and the fuselage through rigid connection. The dynamics solution module constructs the system dynamics equations based on the Kane method. The input module outputs the control variables from the received flight control law. The output module outputs the generalized velocity derivative, attitude data, motor drive torque, and tilt shaft load torque. The propeller module's rotational degree of freedom is driven and controlled by the corresponding motor, and its tilting degree of freedom is controlled by the corresponding servo motor. Its inertial tensor is used to automatically generate the cross product of the propeller's rotational angular velocity and tilting angular velocity to model the gyro coupling effect and reflect it in the aircraft's roll and yaw responses. The Kane method is used to model the dynamics of the system. By constructing partial velocity expressions and inertial force forms for each component, the system's equations of motion are formed based on d'Alembert's principle. The equations of motion are solved numerically using a solver in the Simulink environment.

2. The tilt rotor dynamics simulation method based on multibody dynamics according to claim 1, characterized in that, The modular system construction includes: During the initialization phase, the structural topology, mass properties, inertia tensor, and initial state of all components are defined. Coordinate settings are implemented by assigning generalized coordinates and velocity variables to each module and establishing coordinate transformation relationships. Kinematic modeling is used, and vector analysis methods are employed to calculate the velocity and acceleration of each component, constructing partial velocity representations. Dynamic modeling projects external forces, gravity, and inertial forces to various generalized directions to generate generalized force vectors; Assemble the dynamic equations, calculate the difference between inertial force and external force, and generate the Kane equations by taking the dot product for each generalized velocity; Solving and Integrating: Input the equations into the Simulink solver and iteratively update the system state; Data output records the dynamic response variables of each component.

3. The tilt rotor dynamics simulation method based on multibody dynamics according to claim 2, characterized in that, The generalized coordinates of the body module are defined as three-axis position and attitude angles. Its mass properties and inertia tensor are set during the initialization phase. The attitude angles include roll φ, pitch θ, and yaw ψ.

4. The tilt rotor dynamics simulation method based on multibody dynamics according to claim 3, characterized in that, The connection mechanism module is modeled through an active hinge, and explicitly outputs the force exerted by the propeller on the fuselage and the load torque of the tilt shaft.

5. The tilt rotor dynamics simulation method based on multibody dynamics according to claim 4, characterized in that, The output module provides data on motor shaft driving torque, tilting mechanism load torque, and component connection point reaction force.

6. The tilt rotor dynamics simulation method based on multibody dynamics according to claim 5, characterized in that, The numerical stability measures employed in the numerical integration solution specifically include: Set a limiter for the state variable to prevent the value from diverging; Standardize some speed expressions; Integrating using a highly stable ODE solver with a fixed step size.

7. The tilt rotor dynamics simulation method based on multibody dynamics according to claim 6, characterized in that, The scalability supported by the modular system specifically includes: Add any number of propeller modules without modifying the overall framework; Suitable for symmetrical or asymmetrical configurations; Integrate other rigid body modules and interface with existing control law modules.

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