Multi-body dynamics simulation method, system and equipment of chain system and medium

Abstract

A multi-body dynamics simulation method, system, device and medium for a chain system, the method comprising: acquiring a connection relationship among a plurality of target components in the chain system, a structure parameter, a space environment parameter and a task parameter of each target component, and a physical property of a lubricating medium of the chain system under the space environment parameter; correcting the structure parameter of each target component based on the space environment parameter to obtain a target structure parameter; based on the target structure parameters and the connection relation, determining friction characteristic indexes and motion freedom degrees among the multiple target assemblies; constructing a lubrication-volatilization-friction coupling matrix among the plurality of target components; constructing a multi-body dynamic model according to the target structure parameters and the lubrication-volatilization-friction coupling matrix; and acquiring a rotating speed fluctuation curve and load torque data corresponding to the task parameters, and inputting the rotating speed fluctuation curve and the load torque data into the multi-body dynamic model to obtain a dynamic simulation result of the chain system. The reliability of multi-body dynamics simulation of the chain system can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of multi-body dynamics simulation, and in particular to a multi-body dynamics simulation method, system, device and medium for a chain system. Background Art

[0002] With the continuous advancement of aerospace technology, the use of complex spacecraft such as space stations, deep space probes, and on-orbit servicing platforms is becoming increasingly widespread. Chain systems, as a key mechanical transmission method, are widely used in components such as solar wing deployment mechanisms, motion platform drives, and multi-degree-of-freedom robotic arms. Chain systems enable efficient transmission of mechanical energy within confined spaces, meeting the demand for high-performance mechanical transmission in complex space environments.

[0003] In related technologies, multi-body dynamics simulation methods used in ground-based chain systems are often applied to the aerospace field. However, the lubricating medium used in space environments can experience viscosity changes and lubricating film rupture due to drastic temperature fluctuations and vacuum volatilization. These changes directly affect the friction between the chain and sprocket. In existing simulations, friction parameters are often simplified using constants or empirical values, ignoring the dynamic effects of lubrication performance changes on friction, resulting in insufficient reliability in multi-body dynamics simulations of chain systems. Summary of the Invention

[0004] The present application provides a multi-body dynamics simulation method, system, device and medium for a chain system, which are used to improve the reliability of the multi-body dynamics simulation of the chain system in a space environment.

[0005] In a first aspect of the present application, a multi-body dynamics simulation method for a chain system is provided, which is applied to a multi-body dynamics simulation platform, and the method includes: obtaining the connection relationship between multiple target components in the chain system, the structural parameters of each target component, space environment parameters, mission parameters and the physical properties of the lubricating medium of the chain system under the space environment parameters; correcting the structural parameters of each target component based on the space environment parameters to obtain the target structural parameters; determining the friction characteristic indicators and the degrees of freedom of movement between multiple target components based on the target structural parameters and the connection relationship; constructing a lubrication-volatility-friction coupling matrix between multiple target components based on the flow characteristics, physical characteristics, friction characteristic indicators, connection relationship and degrees of freedom of movement of the lubricating medium; constructing a multi-body dynamics model according to the target structural parameters and the lubrication-volatility-friction coupling matrix; obtaining the speed fluctuation curve and load torque data corresponding to the mission parameters, and inputting the speed fluctuation curve and load torque data into the multi-body dynamics model to obtain the dynamics simulation results of the chain system, and the dynamics simulation results include the chain tension distribution of the chain system, the tensioner response behavior and the system transmission error.

[0006] Optionally, the structural parameters of each target component are corrected based on the space environment parameters to obtain the target structural parameters, specifically including: calculating the thermal stress distribution of the target component during the temperature cycle process according to the temperature cycle parameters in the space environment parameters, and determining the thermal deformation of the target component based on the thermal stress distribution; obtaining the mechanical property test data of the target component under different irradiation cumulative times according to the radiation parameters in the space environment parameters, and determining the material property change trend of the target component; establishing a temperature-stress response curve of the target component based on the thermal deformation and the thermal stress distribution, and calibrating the thermal stress critical interval in the temperature-stress response curve; correcting the thermal stress critical interval of the temperature-stress response curve according to the material property change trend to obtain a corrected response curve; determining the offset of the structural parameters of the target component according to the thermal stress critical interval in the corrected response curve, and correcting the structural parameters of the target component based on the offset to obtain the target structural parameters.

[0007] Optionally, the friction characteristic index and the degree of freedom of movement between multiple target components are determined based on the target structure parameters and the connection relationship, specifically including: determining the contact point between the first target component and the second target component based on the target structure parameters and the connection relationship, the first target component and the second target component being any two target components among the multiple target components; determining the relative motion type between the first target component and the second target component based on the connection relationship, and determining the direction of the contact force between the first target component and the second target component at the contact point based on the relative motion type; obtaining roughness data of each contact point, and determining the actual contact state based on the roughness data; determining the magnitude and direction of the friction force between the first target component and the second target component based on the actual contact state and the direction of the contact force, and generating a friction characteristic index; analyzing the constraint type of the first target component and the second target component in the actual contact state based on the connection relationship, and identifying the movable direction and rotation angle of the first target component and the second target component; determining the degree of freedom of movement of the first target component and the second target component based on the movable direction and the rotation angle.

[0008] Optionally, before constructing a lubrication-volatility-friction coupling matrix between multiple target components based on the flow characteristics, physical properties, friction characteristic indicators, connection relationships and degrees of freedom of movement of the lubricating medium, the method also includes: constructing a contact area distribution map of the contact area of the lubricating medium based on the actual contact state of the contact point, where the contact area is determined by the contact point; and determining the flow characteristics of the lubricating medium in each contact area based on the viscosity parameters in the physical characteristics and the direction of contact force.

[0009] Optionally, a lubrication-evaporation-friction coupling matrix is constructed between multiple target components based on the flow characteristics, physical characteristics, friction characteristic indices, connection relationships and degrees of freedom of movement of the lubricating medium, specifically including: determining the lubrication state type of the lubricating medium in each contact area based on the flow characteristics and degrees of freedom of movement, the lubrication state types including fluid lubrication area, mixed lubrication area and boundary lubrication area; calculating the volatilization rate of the lubricating medium in each contact area based on the saturated vapor pressure parameter in the physical characteristics; determining the friction coefficient of each contact area based on the friction characteristic indices; establishing a mapping relationship between the lubrication state type and the friction coefficient based on the volatilization rate and the friction coefficient; obtaining a three-dimensional structural model of the chain system; determining the spatial topological order of the target components in the chain system based on the connection relationship and the three-dimensional structural model; arranging the flow characteristics, volatilization rate and friction coefficient of the lubricating medium in each contact area in a spatial topological order to obtain a lubrication-evaporation-friction coupling matrix.

[0010] Optionally, a multi-body dynamics model is constructed based on the target structural parameters and the lubrication-evaporation-friction coupling matrix, specifically including: based on the target structural parameters, dividing the target components into a driving sprocket component, a driven sprocket component, a chain component and a tensioner component; based on the flow characteristics in the lubrication-evaporation-friction coupling matrix, determining the lubrication state parameters of the lubricating medium; based on the lubrication state parameters, constructing a meshing clearance correction function between the first category target components, the first category target components including the driving sprocket component, the driven sprocket component and the chain component; based on the evaporation rate in the lubrication-evaporation-friction coupling matrix, constructing a friction damping change relationship of the tensioner component during the lubrication state change process; analyzing the friction coefficient change trend of the friction coefficient in the lubrication-evaporation-friction coupling matrix during the lubrication state change process, and establishing a dynamic force transmission correction function between the second category target components during the meshing process based on the friction coefficient change trend, the second category target components including the driving sprocket component and the chain component; obtaining a multi-body dynamics model based on the meshing clearance correction function, the friction damping change relationship and the dynamic force transmission correction function.

[0011] Optionally, after obtaining the dynamic simulation results of the chain system, the method further includes: evaluating the simulation results to obtain simulation evaluation results, and when the simulation evaluation results do not meet the preset evaluation requirements, adjusting the connection relationship and structural parameters based on the simulation evaluation results, until the simulation evaluation results meet the preset evaluation requirements and stop the evaluation.

[0012] In a second aspect of the present application, a multi-body dynamics simulation system for a chain system is provided, comprising: an acquisition module for acquiring the connection relationship between multiple target components in the chain system, the structural parameters of each target component, space environment parameters, mission parameters and the physical properties of the lubricating medium of the chain system under the space environment parameters; a correction module for correcting the structural parameters of each target component based on the space environment parameters to obtain the target structural parameters; a determination module for determining the friction characteristic indicators and motion degrees of freedom between multiple target components based on the target structural parameters and the connection relationship; a first construction module for constructing a lubrication-volatility-friction coupling matrix between multiple target components based on the flow characteristics, physical characteristics, friction characteristic indicators, connection relationship and motion degrees of freedom of the lubricating medium; a second construction module for constructing a multi-body dynamics model according to the target structural parameters and the lubrication-volatility-friction coupling matrix; a simulation module for acquiring a speed fluctuation curve and load torque data corresponding to the mission parameters, and inputting the speed fluctuation curve and load torque data into the multi-body dynamics model to obtain the dynamics simulation results of the chain system, which include the chain tension distribution, tensioner response behavior and system transmission error of the chain system.

[0013] In the third aspect of the present application, an electronic device is provided, including a processor, a memory, a user interface and a network interface, the memory is used to store instructions, the user interface and the network interface are both used to communicate with other devices, and the processor is used to execute the instructions stored in the memory so that the electronic device performs any of the methods described above.

[0014] In a fourth aspect of the present application, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores instructions, and when the instructions are executed, any one of the above methods is executed.

[0015] In summary, one or more technical solutions provided by this application have at least the following technical effects or advantages: 1. By incorporating space environmental parameters, mission parameters, and the physical properties of the lubricating medium in a space environment, the environmental adaptability of the structural parameters of each target component in the chain system can be modified, resulting in target structural parameters that better align with actual operating conditions. Furthermore, by integrating the connection relationships between the target components, the friction characteristics and degrees of freedom between the target components are further determined, effectively reflecting the relative motion behavior of the multi-body system. By constructing a lubrication-evaporation-friction coupling matrix, the flow characteristics of the lubricating medium are dynamically correlated with its viscosity changes, evaporation behavior, and friction state in the space environment. This coupled modeling of lubrication performance changes and friction characteristics is achieved, effectively overcoming the inaccurate dynamic simulation caused by static simplification of friction parameters in existing techniques. A multibody dynamics model based on the target structural parameters and the coupling matrix accurately characterizes the dynamic transmission behavior of the chain system in a space environment. By inputting the speed fluctuation curve corresponding to the mission parameters and load torque data into the constructed multibody dynamics model, the resulting dynamic simulation results fully reflect the chain tension distribution, tensioner response, and system transmission error of the chain system under actual mission conditions, improving the reliability of multibody dynamics simulations of chain systems in space environments.

[0016] 2. By calculating the thermal stress distribution and thermal deformation under temperature cycling and combining it with the material performance trends under radiation conditions, a representative temperature-stress response curve is established. The critical thermal stress range is calibrated and dynamically corrected within this curve, accurately reflecting the stress response characteristics of the component in the complex space environment. Based on the corrected temperature-stress response curve, the offset of the structural parameters is effectively determined, achieving precise correction of the target structural parameters. This enhances the adaptability of the multibody dynamics model to extreme operating conditions and improves the reliability and engineering applicability of the chain system simulation results.

[0017] 3. By combining target structural parameters with connection relationships, the contact points and relative motion types between multiple target components are accurately identified. The actual contact state can be determined based on the roughness data of the contact points and the direction of the contact force, thereby obtaining the magnitude and direction of the friction between each target component and constructing a physically based friction characteristic index. Based on the actual contact state, the constraint type between components is analyzed, and the movable direction and rotation angle of each component at the contact interface are clarified, thereby determining the degrees of freedom of motion. This effectively improves the accuracy of friction modeling and the sophistication of motion constraint modeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the system architecture of an embodiment of a multi-body dynamics simulation method of a chain system or a multi-body dynamics simulation system of a chain system according to an embodiment of the present application; Figure 21 is a flow chart of a multi-body dynamics simulation method for a chain system in an embodiment of the present application; Figure 3 This is a schematic structural diagram of a multi-body dynamics simulation system for a chain system in an embodiment of the present application; Figure 4 It is a structural diagram of an electronic device in an embodiment of the present application.

[0019] Explanation of the accompanying drawings: 301, acquisition module; 302, correction module; 303, first determination module; 304, first construction module; 305, second construction module; 306, simulation module; 307, second determination module; 308, evaluation module; 401, processor; 402, communication bus; 403, user interface; 404, network interface; 405, memory. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments.

[0021] Figure 1 An exemplary system architecture 100 is shown, to which an embodiment of a multi-body dynamics simulation method for a chain system or a multi-body dynamics simulation system for a chain system of the present application can be applied.

[0022] like Figure 1 As shown, the system architecture 100 may include multiple terminal devices 101, 102, 103, a network 104 and a simulation server 105. The system architecture is suitable for executing a multi-body dynamics simulation method of a chain system. The network 104 is used to provide a medium for a communication link between the terminal devices 101, 102, 103 and the simulation server 105. The network 104 may include various types of connection methods, such as wired networks, wireless communication links, optical fiber communications, etc., to support efficient data transmission and the execution of remote simulation tasks. The terminal devices 101, 102, 103 are used to obtain and input parameters required for the simulation of the chain system, including but not limited to: the connection relationship between multiple target components in the chain system, the structural parameters of each target component, space environment parameters, task parameters and the physical properties of the lubricating medium in a specific space environment.

[0023] The terminal device can be installed with multi-body dynamics simulation data processing software for data acquisition, preprocessing, model configuration and other operations. The user can input various simulation parameters through the graphical user interface and upload the data to the simulation server 105 through the network 104. The terminal devices 101, 102, and 103 can be hardware devices, such as workstations, laptops, tablets, or embedded industrial control terminals with graphics and computing capabilities; or they can be software modules deployed on the above hardware devices, such as client programs for simulation task configuration. The simulation server 105 can be a single high-performance computing server or a distributed simulation computing platform composed of multiple computing nodes, supporting parallel computing and large-scale parameter simulation tasks. The server can be deployed as hardware or implemented as a software module distributed across multiple nodes. It should be noted that the number and specific implementation methods of the terminal devices, networks, and servers in the above architecture can be flexibly adjusted according to the actual simulation scenario.

[0024] Figure 2 It is a flow chart of a multi-body dynamics simulation method of a chain system in an embodiment of the present application.

[0025] See also Figure 2 In an embodiment of the present application, a multi-body dynamics simulation method for a chain system is applied to a multi-body dynamics simulation platform. The method includes: S201, obtaining the connection relationship between multiple target components in the chain system, the structural parameters of each target component, the space environment parameters, the mission parameters, and the physical properties of the lubricating medium of the chain system under the space environment parameters; In step S201, the connection relationships between target components are obtained from the chain system's design drawings and assembly model. The mechanical interface types between the chain and various components, such as sprockets, tensioners, and guide rails, are identified. Corresponding connection methods include revolute joints, translation joints, and rigid joints. These connection relationships not only reflect the relative motion characteristics between components but also determine the distribution of degrees of freedom across the entire system, serving as a prerequisite for constructing kinematic constraint equations.

[0026] Obtain the structural parameters of each target component, including geometric features (such as chain pitch, number of sprocket teeth, and pitch diameter), material properties (such as density and thermal expansion coefficient), and mass parameters (such as moment of inertia). These structural parameters can be obtained by reading CAD model data using 3D modeling software or by combining material databases with experimental measurement results to ensure accurate reflection of the component's geometric and physical properties during the modeling process. To adapt the dynamic model to the space mission environment, it is also necessary to obtain the space environment parameters of the chain system, including temperature cycle parameters, vacuum level, space radiation energy, and microgravity level. Temperature cycle parameters refer to the temperature variation range, rate of change, and cycle period experienced by the target component during orbital operation. These parameters are typically caused by alternating sunlight and shadows, reflecting the thermal load characteristics of the target component during multiple heating and cooling cycles. Mission parameters describe the operating state of the chain system during the mission cycle. Mission parameters include at least the drive speed range, speed fluctuation curve, load torque variation data, and load spectrum information. These parameters are typically provided by the system design unit or generated using a load spectrum extraction algorithm.

[0027] Furthermore, the physical properties of the lubricant selected for the chain system under space environmental parameters must be determined, including its viscosity-temperature relationship, ultimate load-bearing capacity, lubricant film thickness formation capability, and evaporation rate. These physical properties are obtained through vacuum thermogravimetric analysis, molecular dynamics simulations, or literature test data.

[0028] S202: Correcting the structural parameters of each target component based on the space environment parameters to obtain target structural parameters. In a space environment, target components are easily affected by extreme environmental factors such as vacuum, weightlessness, and extreme temperature, which may cause changes in structural parameters. Therefore, in order to obtain more accurate simulation results, correcting the structural parameters of each target component based on the space environment parameters in step S202 to obtain target structural parameters may include steps S2021 to S2025: S2021. Calculate the thermal stress distribution of the target component during the temperature cycling process according to the temperature cycling parameters in the space environment parameters, and determine the thermal deformation of the target component based on the thermal stress distribution; To ensure that the structural parameters in the multibody dynamics model of the chain system truly reflect the actual state of the target component in space service, it is necessary to calculate the thermal stress distribution of the target component during temperature cycling based on the temperature cycling parameters in the space environment parameters. The thermal deformation is then further determined based on this thermal stress distribution. The temperature cycling parameters in the space environment refer to the temperature variation range, rate of change, and cycle period caused by the target component's periodic entry into sunlight and shadow areas during on-orbit operation.

[0029] To accurately calculate the thermal stress distribution, a finite element analysis (FEA) model is first established based on the target component's 3D CAD model. A simulation tool with thermal-structural coupling capabilities, such as ANSYS, is used. Temperature cycle parameters are defined as periodic thermal boundary loads applied to the FEA model surface. The FEA model must consider thermophysical parameters such as the material's coefficient of thermal expansion, thermal conductivity, and temperature-dependent elastic modulus to ensure accurate heat conduction and thermal stress calculations. During the simulation, transient thermal analysis is used to determine the temperature response of the nodes in the time domain. The temperature field is then applied as a load to the structural field, performing a thermal-structural coupling solution to determine the thermal stress distribution of the target component throughout the entire temperature cycle. The thermal stress results are output as Von Mises equivalent stresses, reflecting the stress levels in key structural regions under the influence of multi-point temperature differences. Furthermore, after the thermal stress analysis is completed, the thermally induced displacement values of each key node are extracted from the structural solution to calculate the thermal deformation of the target component under the temperature cycle. Thermal deformation usually manifests itself in the form of linear expansion, angular offset or hole position drift. For example, the chain link length expands by 0.02mm in the high-temperature section and shrinks by 0.015mm in the low-temperature section. These changes will affect the pitch matching accuracy and meshing dynamic characteristics of the chain.

[0030] S2022. Based on the radiation parameters in the space environment parameters, obtain mechanical property test data of the target component at different cumulative irradiation times to determine the material property change trend of the target component; The radiation parameters of the orbital environment in which the target component is located include the type of radiation particles, energy level, time-accumulated dose, etc. The radiation parameters can be simulated by mission orbit simulation software (such as SPENVIS), or obtained from the on-orbit radiation spectrum data provided by the space mission. Subsequently, the mechanical properties test data under different cumulative irradiation times are obtained for the main materials of the target component. The mechanical properties test data comes from ground-based accelerated irradiation experiments. The specimens are irradiated with a fixed dose using an equivalent energy particle source, and then tensile, compression or fatigue tests are performed according to standard mechanical test methods (such as ASTME8). The elastic modulus, yield strength, ultimate strength and elongation at break corresponding to each irradiation time point are recorded. The mechanical properties data at multiple time points are curve fitted, and the exponential decay model is used to establish a material performance change trend curve.

[0031] S2023. Establish a temperature-stress response curve of the target component based on the thermal deformation and thermal stress distribution, and calibrate the thermal stress critical range in the temperature-stress response curve; First, the thermal stress data and temperature field data output from the thermal-structural coupling simulation are processed accordingly. For each thermal cycle time step, a stress response dataset is extracted for the target component during the temperature change process. The horizontal axis of the stress response dataset represents the temperature value, and the vertical axis represents the Von Mises equivalent stress value at the corresponding node. A continuous temperature-stress response curve is formed by fitting multiple sampling points throughout the entire temperature cycle. The temperature-stress response curve can be fitted using polynomial or piecewise linear fitting to ensure that it reflects both overall trends and captures local mutation characteristics.

[0032] The temperature-stress response curve reflects the stress evolution law of the structure at different temperatures. Due to the uneven thermal expansion coefficient of the material, the complexity of the geometric structure and the coupling effect of boundary conditions, temperature changes will cause the stress response to be non-linear. Therefore, after completing the construction of the response curve, it is necessary to calibrate the thermal stress critical interval on the curve. The thermal stress critical interval refers to the temperature section where the stress level is close to or exceeds the yield strength of the material. It is usually determined by comparing the stress value in the curve with the yield limit of the non-degraded material. If it is found that the stress in the temperature section continuously or discontinuously exceeds the yield threshold, the section can be determined as the critical interval. In order to improve the accuracy of the calibration, the response curves of multiple structural areas need to be jointly analyzed to ensure that the calibration results are not affected by single-point local outliers.

[0033] S2024. According to the material property change trend, the thermal stress critical interval of the temperature-stress response curve is modified to obtain a modified response curve; In the specific implementation process, first, based on the temperature-stress response curve established in the previous step, the upper and lower boundary values of the critical interval of thermal stress are extracted. This interval is usually indexed by the Von Mises equivalent stress, which corresponds to the yield strength range when the material has not yet degraded. Then, the yield strength change curve of the target component material under different cumulative irradiation times is retrieved. The change trend usually shows a slowly decreasing nonlinear feature. Some materials decrease significantly in the early irradiation stage and then tend to stabilize. The yield strength value corresponding to the curve at a specified cumulative irradiation time point (such as the mission design life node) is compared with the original yield strength to obtain the correction amplitude of the critical interval of thermal stress.

[0034] The corresponding critical stress interval boundary in the original response curve is lowered, and the adjustment ratio is linearly or nonlinearly mapped according to the ratio of material performance degradation. For example, if the yield strength of the material decreases by 10% after 500 hours of irradiation, the upper and lower limits of the thermal stress critical interval are respectively shifted down by 10%. For example, in the aluminum alloy material used in any link component, its yield strength is measured by irradiation test to drop from the initial 310MPa to 275MPa, a decrease of about 11.3%. In the original temperature-stress response curve, the critical interval is 280MPa to 300MPa. According to the decrease ratio, the interval is corrected to 248.7MPa to 266.7MPa, which constitutes the input of the modified response curve to ensure that subsequent structural corrections are based on the actual state of the material and avoid overestimating the structural bearing capacity.

[0035] S2025. Determine an offset of the structural parameters of the target component according to the critical interval of thermal stress in the correction response curve, and correct the structural parameters of the target component based on the offset to obtain target structural parameters.

[0036] After the temperature-stress response curve is corrected, the thermal stress critical interval can accurately reflect the stress limit state of the target component within a specific temperature range. At this time, it is necessary to compare the thermal stress response of this critical interval with that under the original design state to identify the local overload area caused by the decrease in material yield strength. In the temperature section corresponding to the corrected response curve, the geometric response of the key dimensional parts of the structure is extracted and compared with the initial design value to obtain the offset value. This offset can be positive (expansion) or negative (contraction) and may be accompanied by a buckling trend or deformation delay caused by the decrease in material stiffness. For material parameters, such as elastic modulus and Poisson's ratio, synchronous corrections are made based on the material performance change trend curve to ensure that the structural mechanical behavior response is consistent with the material state. The offset is used as a correction factor and applied to the original structural parameters to generate the target structural parameters. The target structural parameters include not only the corrected geometric dimensions, but also the temperature-time related material property inputs.

[0037] For example, in a sprocket assembly, analysis of the modified response curve revealed that thermal stress in the tooth root region reached the material yield strength within the critical temperature range of 95°C to 110°C. Further analysis, combined with thermal deformation data, revealed that the pitch diameter expanded by an average of 0.018mm within this range, while the material elastic modulus decreased by approximately 4%. Based on this, the original pitch diameter parameter was revised from 102.000mm to 102.018mm, and the elastic modulus from 110GPa to 105.6GPa. These parameters were then input into the dynamics simulation model as target structural parameters, improving the model's prediction accuracy under the coupled thermal load and material degradation scenario.

[0038] S203, determining friction characteristic indices and degrees of freedom of motion between multiple target components based on target structural parameters and connection relationships; In step S203, to ensure that the multi-body dynamics model of the chain system accurately reflects the interactions between the target components, the friction behavior and kinematic properties between the components are gradually established based on the target structural parameters and connection relationships. The first target component and the second target component are any two components in the chain system that are physically connected or in contact, such as a sprocket and a chain link. The method may include the following steps: determining the contact point between the first target component and the second target component according to the target structure parameters and the connection relationship, where the first target component and the second target component are any two target components among the multiple target components; determining the relative motion type between the first target component and the second target component based on the connection relationship, and determining the direction of the contact force between the first target component and the second target component at the contact point based on the relative motion type; acquiring roughness data of each contact point, and determining the actual contact state according to the roughness data; determining the magnitude and direction of the friction force between the first target component and the second target component based on the actual contact state and the direction of the contact force, and generating a friction characteristic index; analyzing the constraint type of the first target component and the second target component in the actual contact state based on the connection relationship, and identifying the movable direction and rotation angle of the first target component and the second target component; and determining the degree of freedom of motion of the first target component and the second target component according to the movable direction and the rotation angle.

[0039] Specifically, the three-dimensional geometric model data and connection relationship map contained in the target structure parameters are first read to identify the position where there is physical contact or force transmission between any two components in the chain system. Taking the sprocket and the chain link as an example, by analyzing their meshing boundaries and geometric overlap areas, it is determined that there is periodic line contact between the two during the meshing process. Using CAD modeling or finite element pre-processing modules, the intersection area of the contact surface is extracted in the assembly model, and the contact point coordinates are calibrated by solving the geometric center or the maximum contact pressure point. The determination of the contact point is the basis of friction modeling. Its position determines the contact force action path and the friction response area, and also provides a coordinate reference for subsequent contact state and kinematic analysis.

[0040] After completing the contact point positioning, it is necessary to determine the relative motion form between the first target component and the second target component based on the connection relationship between the components. The relative motion forms are mainly divided into sliding, rolling and compound motion, and different motion forms correspond to different friction behavior patterns. Taking the movement of the chain link on the sprocket tooth surface as an example, based on the trajectory curve of the chain link around the rotation center of the sprocket, it can be judged that it is a rolling-slip compound contact. After determining the relative motion form, a local orthogonal coordinate system is established at the contact point, with the relative velocity direction between the components as the tangent and the normal direction as the contact force direction. According to Newton's third law, the contact force always acts along the local normal direction to resist the relative penetration between components. At the same time, the tangential velocity direction is used to determine the subsequent friction force direction.

[0041] The microscopic contact state at the contact point is significantly affected by the surface roughness, so it is necessary to obtain the roughness parameters of the contact surface material, usually expressed as Ra (arithmetic mean height) or Rz (maximum height difference), which can be obtained through a three-dimensional profilometer or design process parameters. Roughness determines the microscopic morphology of the contact surface, which in turn affects the actual contact area and local pressure distribution. Based on the Greenwood-Williamson statistical contact model, the rough surface can be regarded as an array composed of a large number of micro-asperities. Under the action of normal load, these micro-asperities will undergo different degrees of elastic or plastic deformation. If most of the micro-asperities are in an elastic state, the overall contact state is elastic contact; if most of them yield, it is judged to be plastic contact; if both exist, it is a mixed contact. The actual contact state determines the nonlinear response mode of the subsequent friction characteristics, so it is necessary to combine the roughness data with the load calculation results for accurate judgment.

[0042] Based on the known contact state (elastic, plastic, or mixed), the magnitude and direction of the friction force are calculated, taking into account the direction of the contact force. First, the normal load value at the contact point is obtained. This value is determined by the direction of the contact force and the resulting force at the contact point. Next, the corresponding friction coefficient is selected based on the contact type: for elastic contact, the static friction coefficient is used; for plastic contact with significant slip, the dynamic friction coefficient is used. If there is a change in lubrication state, the speed-dependent Stribeck friction model is introduced. In the Stribeck friction model, the friction force transitions from static friction to dynamic friction as the relative sliding velocity of the contact point increases, reflecting the effect of changes in lubricating film thickness on frictional resistance. The direction of the friction force is determined by the relative sliding direction of the contact point and is always opposite to it. Finally, based on the normal load, friction coefficient, and sliding direction, the friction force vector is calculated, and friction characteristic indicators are generated, including the static friction limit, dynamic friction range, and speed sensitivity coefficient.

[0043] In order to further establish the motion boundary between components, it is necessary to comprehensively analyze the constraint type based on the connection relationship and contact state. Specifically, read the connection method described in the connection relationship, such as hinge, sliding pair, rigid connection, etc., and judge the constraint strength in combination with the normal stiffness and tangential friction characteristics of the contact point. If the normal stiffness of the contact point is extremely high and there is no slip, it is considered a strong constraint direction and has no freedom of movement; on the contrary, if there is slip or flexible support, it is considered that there is freedom in this direction. Taking the chain link and the tensioner guide rail as an example, the chain link has linear sliding along the guide rail direction, while the vertical direction is restricted, and the rotational freedom is also partially restricted due to the friction of the guide rail surface. Using the spatial constraint matrix method, each direction (x, y, z) and plane rotation (around x, y, z) is mapped to a mobility flag of 0 or 1, clarifying the free or constrained state of the components in the six directions at the contact point, thereby providing a basis for the definition of degrees of freedom.

[0044] After obtaining the mobility in each direction, the degrees of freedom of motion between the target components are comprehensively derived. The degrees of freedom of motion refer to the number of independent movements or rotations of components relative to each other, usually 6: 3 linear displacement directions and 3 rotation directions around the axis. Through the mobility matrix generated in the previous step, the degrees of freedom are judged one by one: a value of 1 indicates that there is a valid degree of freedom in that direction, and a value of 0 indicates that it is restricted by contact, connection or friction constraints. For example, a chain link in a guide rail usually only has one linear degree of freedom along the guide rail direction, and the remaining directions are restricted; while the connection between the chain link and the chain pin allows rotation around the pin axis, thus retaining one rotational degree of freedom. This degree of freedom information is encoded as a degree of freedom vector or degree of freedom matrix, which serves as the basis for defining the motion behavior of the component in the subsequent multi-body dynamics model.

[0045] S204, constructing a lubrication-evaporation-friction coupling matrix between multiple target components based on the flow characteristics, physical properties, friction characteristic indicators, connection relationships, and degrees of freedom of motion of the lubricating medium; To model the lubrication performance between multiple components in a chain system in a space environment, the spatial distribution and dynamic flow behavior of the lubricant in each contact area must be determined before constructing the lubrication-volatility-friction coupling matrix. This can include the following steps: constructing a contact area distribution map of the lubricant contact area based on the actual contact state of the contact points, where the contact area is determined by the contact points; and determining the flow characteristics of the lubricant in each contact area based on the viscosity parameters and contact force directions in the physical properties.

[0046] Specifically, in order to ensure that the multi-body dynamics simulation model can accurately reflect the actual action state of the lubricating medium on the contact interface of the target component, it is necessary to construct a contact area distribution map of the lubricating medium based on the actual contact state of the contact point, and further calculate the flow characteristics of the lubricating medium in this area. First, the delineation of the contact area is centered on the previously identified contact point and expanded in combination with the actual contact state. The contact state includes the contact area, surface roughness and micro-asperity distribution characteristics. These parameters determine the coverage pattern of the lubricant at the microscale. By projecting the contact points onto the contact surface in three-dimensional space and combining the contact pressure distribution and surface morphology parameters, a contact area distribution map reflecting the lubrication distribution range, thickness gradient and contact effective area can be generated using numerical interpolation or finite element contact algorithm. The generation of the contact area distribution map is a key step in lubrication modeling. It expands the originally discrete contact points into a two-dimensional contact domain that can be used for fluid flow analysis.

[0047] After obtaining the contact area distribution map, it is necessary to further consider the flow characteristics of the lubricating medium in this area. The lubricating medium in the space environment is usually a low-volatility solid-liquid composite lubricating material, and its flow properties are highly sensitive to temperature and shear rate. Therefore, the flow characteristics must be calculated in combination with the physical properties of the lubricating medium under the current environmental parameters, especially the viscosity parameters. By establishing a local coordinate system in the contact area and projecting the direction of the contact force as a shear-driven component, a shear flow model (such as a Newtonian fluid model) can be used to calculate the shear stress distribution, velocity gradient, and velocity profile of the lubricating film at different positions. If there is a change in the microscopic contact gap, the Reynolds lubrication equation must be introduced to estimate the film pressure and local redistribution effect.

[0048] In step S204, a lubrication-volatility-friction coupling matrix between multiple target components is constructed based on the flow characteristics, physical characteristics, friction characteristic indicators, connection relationships, and degrees of freedom of motion of the lubricating medium, which may include steps S2041-S2047: S2041, based on the flow characteristics and degrees of freedom of motion, determining the lubrication state type of the lubricating medium in each contact area, the lubrication state types including fluid lubrication area, mixed lubrication area, and boundary lubrication area; In step S2041, to achieve high-precision construction of the lubrication-volatility-friction coupling matrix, it is necessary to first determine the lubrication state type of the lubricating medium in each contact area. The lubrication state type is an important basis for reflecting the working mode of the lubricating medium at the contact interface of the target component, and directly determines the selection of the friction coefficient and the calculation method of energy loss. Typical lubrication state types include fluid lubrication zone, mixed lubrication zone, and boundary lubrication zone. The fluid lubrication zone indicates that the contact surface is completely separated by a lubricating film, and the friction force is mainly generated by lubricant shear; the mixed lubrication zone indicates that some microscopic contact points have penetrated the lubricating film, and solid contact and lubricating film shear coexist; the boundary lubrication zone indicates that the lubricant has basically failed, and the friction force is caused by direct solid contact and the action of the surface adsorption film.

[0049] During the specific implementation process, the lubrication film thickness-roughness ratio (abbreviated as λ value) is first calculated based on the calculated flow characteristic parameters of the lubricating medium in each contact area, including the lubrication film thickness distribution, shear rate, and local pressure gradient, combined with the relative sliding velocity determined by the degrees of freedom of movement in the contact area. The lubrication film thickness-roughness ratio is an internationally recognized basis for determining the lubrication state and is defined as the ratio of the lubrication film thickness to the root mean square value of the surface roughness of the contact surface. If the λ value is greater than 3, it is determined to be a fluid lubrication area; if the λ value is between 1 and 3, it is a mixed lubrication area; when the λ value is less than 1, it is a boundary lubrication area. The calculation process divides the contact area into grids, performs local evaluations at each grid node, and then aggregates the results into the overall lubrication state type of the contact area.

[0050] S2042. Calculate the volatilization rate of the lubricating medium in each contact area based on the saturated vapor pressure parameter in the physical properties; Step S2042 requires calculating the lubricant's evaporation rate in each contact area based on the lubricant's saturated vapor pressure parameter, a physical property of the lubricant. The lubricant's evaporation rate is a key variable in determining its effective lifespan and interfacial friction. Lubricant molecules are particularly prone to escaping into free space under vacuum, high temperature, and low pressure conditions, causing the lubricating film to gradually thin or even disappear.

[0051] In specific implementation, it is first necessary to extract its saturated vapor pressure parameters from the physical properties database of the lubricating medium. Saturated vapor pressure refers to the air pressure when the liquid lubricant and its vapor reach dynamic equilibrium at a given temperature, and is usually an exponential function of temperature. In order to accurately calculate the volatilization rate, a micro-scale evaporation calculation formula based on the Knudsen volatilization model is used, in which the volatilization rate is related to the saturated vapor pressure, the surface temperature of the lubricating film, and the molecular weight. In each contact area, the surface temperature distribution map of the lubricating film obtained earlier and the local pressure conditions are combined and substituted into the formula: in, is the mass volatilization rate per unit area, P satis the saturated vapor pressure at the current temperature, M is the molecular weight, R is the gas constant, and T is the local temperature. During the calculation, the contact area is discretized into multiple small grid cells. The local volatilization rate is calculated in each cell, and the total volatilization rate for the entire contact area is finally obtained through the area-weighted average method.

[0052] S2043. Determine the friction coefficient of each contact area based on the friction characteristic index; Step S2043 requires further calculation of the friction coefficient for each contact area based on the previously determined friction characteristics. As a key input in the contact force model, the friction coefficient directly affects the frictional resistance between the contact pairs and is a crucial physical parameter that determines chain system behavior, including energy loss, heat accumulation, and noise response. In space, due to the extremely low pressure, volatile lubricants, and significant material degradation, the friction coefficient is no longer a fixed constant but a dynamic variable that varies with multiple factors, including lubrication status, temperature, surface topography, and load.

[0053] During the implementation, the friction characteristic index generated in the previous step is first used. This includes the contact type, contact state, static friction coefficient, kinetic friction coefficient, velocity-related coefficient, and contact damping parameter for each contact point. Next, the lubrication state type within the contact area is correlated with the friction characteristic index, and a partition mapping approach is used to determine the calculation formula for the friction coefficient. In the fluid lubrication zone, the friction coefficient is primarily driven by the shear behavior of the lubricating medium. In this case, a viscous friction model is used, where the friction coefficient is the ratio of shear stress to normal load. In the mixed lubrication zone, a weighted average model is used based on the ratio of the local actual contact area to the lubricating film thickness, combining boundary friction and fluid friction components. In the boundary lubrication zone, the kinetic friction coefficient provided in the friction characteristic index is directly used, dynamically adjusted based on the contact surface roughness and temperature correction values. The calculation process is based on the coupling relationship between the actual contact mechanism and the lubrication state, relying on the joint modeling principles of contact mechanics and tribology. The final friction coefficient result is output as a two-dimensional matrix, with each cell in the matrix corresponding to the friction coefficient value of a grid cell within the contact zone.

[0054] S2044. Establishing a mapping relationship between lubrication state type and friction coefficient based on the volatilization rate and friction coefficient; Based on the calculated lubricant evaporation rate and the friction coefficient within the contact area, a mapping relationship between the lubrication state type and the friction coefficient is established. Because lubricant evaporation in space can cause the lubrication state to shift, for example, from fluid lubrication to mixed lubrication and ultimately to boundary lubrication, a dynamic mapping mechanism is needed to adjust the friction coefficient in real time based on lubricant loss. This improves the sensitivity and accuracy of the multibody dynamics model to lubrication degradation processes.

[0055] In specific implementation, the contact area is first used as the basic unit, and the friction coefficient value obtained in the previous step is preliminarily paired with the corresponding lubrication state type to form an initial mapping sample set. Next, the volatilization rate of the lubricating medium is introduced as a time-varying factor to establish a model for the decrease of lubricating film thickness over time. This thickness model is linked to the surface roughness ratio to calculate the lubrication state migration threshold. Each lubrication state interval corresponds to a friction coefficient interval, and the friction coefficient value within the interval can be continuously calculated by a linear or nonlinear interpolation function. The mapping relationship is usually expressed in the form of a multi-segment piecewise function, where the independent variable is the lubricating film thickness or volatilization time, the dependent variable is the friction coefficient, and the inflection point of the function corresponds to the demarcation point of the lubrication state. The function construction process combines tribological test data with the physical model fitting results to ensure that the mapping relationship can reflect the actual physical process and has numerical stability. The final generated mapping function is embedded in the lubrication-volatilization-friction coupling matrix to realize the automatic update of the friction coefficient as the lubrication state changes.

[0056] S2045. Obtain a three-dimensional structural model of the chain system; Import the CAD model of the entire chain system structure through 3D modeling software, or use laser scanning and other methods to digitally model the physical chain system to obtain 3D geometric data of major target components including sprockets, chain links, pins, tensioners, etc.

[0057] S2046. Determine the spatial topological order of target components in the chain system based on the connection relationship and the three-dimensional structure model; The implementation of step S2046 requires determining the spatial topological order of each target component in the chain system based on the connection relationship and the three-dimensional structure model. The spatial topological order refers to establishing a set of ordered data structures according to the actual connection method of the target components in the chain system and the assembly order in the three-dimensional space, which is used to describe the spatial adjacency relationship and connection path between the components.

[0058] During the specific implementation process, the direct connection interfaces between components are first extracted based on the coordinate system and assembly positioning information of each target component in the three-dimensional structural model, and then matched with the component connection types defined in the connection relationship. By establishing a component-component connection graph, each target component is used as a graph node and the connection relationship as a graph edge, a directed graph structure is constructed. Subsequently, a depth-first traversal algorithm or a topological sorting algorithm is used to analyze the graph structure to determine the path sequence starting from the driving wheel, passing through the chain link, the pin shaft, to the driven wheel and the tensioner, thereby forming a spatial topological sequence. The connection relationship and spatial position between each pair of adjacent target components are clear, and their corresponding lubrication contact area number and corresponding coordinate index can be marked.

[0059] S2047. Arrange the lubrication medium flow characteristics, volatilization rate, and friction coefficient of each contact area according to a spatial topological order to obtain a lubrication-volatilization-friction coupling matrix.

[0060] First, based on the spatial topological order determined in the previous step, all contact areas are numbered according to the order of their force transmission paths in the chain system. Using the number as the index basis, the lubricating medium flow characteristic parameters (such as shear rate, etc.), volatilization rate values and friction coefficient values obtained in each contact area are extracted and filled into three sets of vectors accordingly. Subsequently, a three-dimensional coupling data matrix is constructed, in which each row represents a contact area, and each column corresponds to the lubrication flow characteristics, medium volatilization rate and local friction coefficient in turn. For the multidimensional parameter of flow characteristics, its internal structure can be nested and stored in the matrix in the form of tensors. For example, the film thickness gradient and shear strain field can be encapsulated in an element unit in the form of sub-matrices or vectors, respectively, to achieve compact expression of high-dimensional data.

[0061] Once the lubrication-evaporation-friction coupling matrix is constructed, it serves as the coupling input module in the dynamic simulation model, updating the evaporation rate and friction coefficient in real time according to the time step during model operation. By solving the kinematic and dynamic equations of the multibody system simultaneously, changes in the lubricating medium's state can directly influence the contact force calculation and energy dissipation estimation process through the coupling matrix. This coupling matrix not only improves the organizational efficiency of the model's data structure but also enables the model to dynamically adjust to lubrication degradation, effectively enhancing the simulation accuracy and predictive reliability of the chain system's real-world physical behavior in complex environments.

[0062] S205, constructing a multi-body dynamics model based on target structural parameters and lubrication-volatility-friction coupling matrix; In step S205, constructing a multi-body dynamics model according to the target structural parameters and the lubrication-evaporation-friction coupling matrix may include steps S2051-S2056: S2051. Based on the target structural parameters, the target assembly is divided into a driving sprocket assembly, a driven sprocket assembly, a chain assembly, and a tensioner assembly; During the specific implementation process, the dimensional parameters, connection relationships, mass distribution, geometric characteristics, and functional description information of each target component are first extracted from the corrected target structural parameters. By identifying components with a circumferential tooth structure and a coaxial connection between the center hole and the drive shaft, they are divided into drive sprocket components and driven sprocket components, where the drive sprocket component is the input end for applying torque and the driven sprocket component is the output end for transmitting power. Subsequently, based on parameter characteristics such as the repeating structure of the chain links, pitch size, and pin connection method, the continuous component group that constitutes the flexible transmission path is identified and classified as a chain component. For target components with elastic element characteristics, used to adjust chain tension, and with axial or angular floating freedom, they are classified as tensioner components based on the spring stiffness, damping characteristics, and installation position in their structural parameters.

[0063] S2052. Based on the flow characteristics in the lubrication-evaporation-friction coupling matrix, the lubrication state parameters of the lubricating medium are determined. Lubrication state parameters are a set of comprehensive characterizing variables used to describe the state of the lubricating medium on the contact surface. They typically include lubricating film thickness, shear stress, local viscosity coefficient, flow direction angle, and film thickness-roughness ratio. The specific implementation process first extracts the flow characteristic data for each contact region from the lubrication-evaporation-friction coupling matrix. Subsequently, the film thickness-roughness ratio method in lubrication theory is used to calculate the λ value (i.e., the ratio of the lubricating film thickness to the root mean square value of the surface roughness) for each contact region. This λ value is a key criterion for determining the lubrication state. Based on this, a lubrication state label is established for each contact region, and the corresponding set of lubrication state parameters is further calculated. To enhance the adaptability of these parameters in dynamic simulations, these lubrication state parameters are standardized so that they can be used as continuous functions in the construction of the contact model correction function. All lubrication state parameters are ultimately encapsulated as a structure and embedded in the data node of the contact region for subsequent modeling steps.

[0064] S2053: constructing a meshing clearance correction function between target components of the first category based on the lubrication state parameter, where the target components of the first category include a driving sprocket assembly, a driven sprocket assembly, and a chain assembly; In a chain system, the contact between the chain link and the sprocket teeth is a periodic meshing process. In ideal modeling, it is usually assumed that the tooth surface and the joint surface are in strict contact without the influence of the lubricating medium. However, in actual systems, the presence of the lubricating film will form a fluid isolation layer between the contact surfaces, resulting in a meshing buffer area of a certain thickness, and the contact stiffness will change due to the pressure distribution of the lubricating film. In order to accurately consider the geometric and mechanical nonlinear changes caused by the lubrication, it is necessary to establish a correction function that can dynamically adjust the contact gap based on the lubrication state parameters obtained in the previous step. In the specific implementation, the key variables such as the lubricating film thickness, film thickness gradient and local shear stress in the lubrication state parameters are first extracted to construct a film thickness function h(x, t). The film thickness function describes the film thickness distribution at different times t in the contact line direction x. Then, the film thickness function is compared with the ideal geometric meshing line of the sprocket tooth surface and the chain link contact surface, and the actual meshing line is defined as the ideal meshing line plus the function perturbation of the lubricating film thickness. Furthermore, combined with the lubrication type corresponding to the lubrication state (such as fluid lubrication, mixed lubrication or boundary lubrication), the correction factor δ is introduced. h , adjust the influence of film thickness on meshing clearance, and finally construct meshing clearance correction function: Δ g (x, t) = h(x, t)·δ h (λ,τ s ), where Δ g (x, t) is the corrected meshing clearance, λ is the film thickness-roughness ratio, τ s is the shear stress, δ h is a correction factor, a weighted function dynamically updated based on changes in lubrication conditions, reflecting the importance of film thickness to clearance correction under different lubrication conditions. The meshing clearance correction function is embedded in the contact pair description of the multibody dynamics model. It serves as a correction term for the relative displacement constraint between the chain and sprocket, enabling the model to account for the cushioning and damping effects of the lubricant film when calculating meshing contact forces.

[0065] S2054. Constructing a friction damping variation relationship of the tensioner assembly during a lubrication state change process based on the volatilization rate in the lubrication-volatilization-friction coupling matrix; The tensioner assembly in a chain drive system primarily maintains chain tension, cushions vibration and shock, and compensates for thermal expansion. It typically consists of an elastic element and a guide rail structure. Its operating characteristics depend on the lubrication state of the contact surfaces. When the lubricant gradually evaporates due to vacuum or high temperature, the lubricating film thickness decreases, and the lubrication state shifts from fluid lubrication to mixed lubrication or even boundary lubrication. This increases the interfacial friction coefficient and significantly increases friction damping, which in turn affects the tensioner's ability to absorb chain vibrations and its response speed.

[0066] In the specific implementation, the lubricant evaporation rate of the tensioner contact area is first extracted from the lubrication-evaporation-friction coupling matrix, and combined with the initial lubricant film thickness, a function model of the lubricant film thickness changing with time is established. Where h0 is the initial film thickness, is the volatile mass rate of the lubricating medium per unit area per unit time. Subsequently, the changing stages of the lubrication state are dynamically derived based on the film thickness-roughness ratio λ(t), and the corresponding friction damping baseline value and adjustment coefficient are set under different lubrication states.

[0067] Construct friction damping change relationship function: C f (t)=C0+η·f(λ(t)), where, C f (t) is the friction damping value at time t, C0 is the initial damping under ideal lubrication conditions, η is the damping adjustment sensitivity coefficient, f(λ(t)) is the lubrication state function, typically a piecewise linear or exponential function that describes the enhanced damping effect of deteriorating lubrication conditions, and λ(t) is the time-dependent evolution of the ratio of film thickness to surface roughness. This friction damping function is embedded in the damping term expression of the tensioner assembly in the multibody system dynamics model, allowing the tensioner to automatically adjust its damping response based on actual lubricant loss during simulation.

[0068] S2055. Analyze the friction coefficient variation trend in the lubrication-volatility-friction coupling matrix during the lubrication state variation process, and establish a dynamic force transmission correction function between target components of the second category during the meshing process based on the friction coefficient variation trend. The target components of the second category include the drive sprocket assembly and the chain assembly. As the lubricant evaporates over time, the lubrication state gradually transitions from fluid lubrication to mixed lubrication and even boundary lubrication, causing the friction coefficient to increase nonlinearly from low to high. This change in the friction coefficient not only affects the magnitude of the tangential friction force but also influences the microslip behavior and energy dissipation mechanism at the contact point.

[0069] In the specific implementation process, the friction coefficient evolution data of all contact areas between the drive sprocket assembly and the chain assembly are first extracted from the lubrication-evaporation-friction coupling matrix. Based on the lubrication state parameters (such as film thickness, shear stress, λ value, etc.) at the corresponding time node, a functional expression for the evolution of the friction coefficient over time or lubrication state is established. This function can be fitted using an exponential growth model or a piecewise polynomial model, and the expression is as follows: μ(t) = μ0 + α·(1-e -β·λ(t)), where μ(t) represents the friction coefficient at any moment, μ0 is the friction coefficient under the initial lubrication state, α is the friction enhancement amplitude, β is the lubrication state sensitivity coefficient, and λ(t) is the time-dependent evolution function of the ratio of film thickness to surface roughness. After establishing the dynamic trend of the friction coefficient through this expression, it is introduced as a variable into the meshing force model. The force transmission correction function is further constructed: F t (t) = F n (t)·μ(t), where F t (t) is the tangential friction force on the contact surface, F n (t) is the normal contact force, and μ(t) is the friction coefficient function. The force transmission correction function is used in multibody dynamics models to update the force transmission state between the sprocket and chain in real time, allowing friction to automatically adjust based on operating time and lubrication degradation. This force transmission correction function extends the traditional static friction model into a dynamic function sensitive to lubrication conditions. This not only enhances the model's physical perception of lubrication degradation but also improves the accuracy of modeling phenomena such as meshing efficiency loss, energy dissipation changes, and system response delays.

[0070] S2056. A multi-body dynamics model is obtained based on the meshing clearance correction function, the friction damping variation relationship, and the dynamic force transmission correction function.

[0071] In the specific implementation process, the driving sprocket assembly, driven sprocket assembly, chain assembly, and tensioner assembly are first modeled. A multibody system topology, including revolute pairs, contact pairs, and elastic pairs, is constructed based on the spatial topological order and connection relationships. For the contact pair between the driving sprocket and chain assemblies, a meshing clearance correction function based on lubrication state parameters is invoked to adjust the normal contact spacing of the meshing contact points in real time. This dynamically corrects the calculated contact stiffness and normal force, ensuring that the model maintains meshing accuracy and mechanical continuity despite changes in lubrication state. Secondly, a friction damping variation relationship based on the evaporation rate is embedded in the contact pair between the tensioner and chain assemblies. This directly feeds back the friction state changes caused by lubricant loss into the tensioner's damping resistance term, enabling the tensioner to automatically adjust its vibration suppression capability and response hysteresis characteristics based on the lubrication state during simulation. Finally, a dynamic force transmission correction function based on the friction coefficient variation trend is invoked in the tangential contact force calculation between the driving sprocket and chain assemblies, allowing the friction force, on which the transmitted torque depends, to change with the evolution of the lubrication state. Introducing the friction coefficient as a time variable into the tangential force model enables dynamic mapping of the chain's force transmission capacity under different lubrication conditions. Finally, based on the three functions mentioned above, the modified contact force, damping force, and friction force are uniformly incorporated into the system's kinematic constraints and dynamic equations to construct a complete multi-body dynamics model.

[0072] S206. Obtain a speed fluctuation curve and load torque data corresponding to the task parameters, input the speed fluctuation curve and load torque data into a multi-body dynamics model, and obtain a dynamic simulation result of the chain system. The dynamic simulation result includes the chain tension distribution of the chain system, the tensioner response behavior, and the system transmission error.

[0073] First, the operating condition type is determined based on the mission parameters, such as startup, steady speed, acceleration / deceleration, or impact load conditions. Then, through experimental measurement, bench simulation, or export from the upper system controller, the speed fluctuation curve of the main drive shaft under the specific mission is obtained. This is a non-constant function with time as the horizontal axis and angular velocity as the vertical axis. This curve can reflect the instantaneous acceleration, inertial disturbance, and periodic disturbance behavior caused by the drive source during the change of operating conditions and is the direct source of the dynamic disturbance at the input end of the chain system. At the same time, load torque data is collected or derived from the load end. This data represents the actual torque required to be transmitted by the output end of the chain system during the mission. It is usually in the form of a time series and is used to describe the changing pattern of the resistance experienced by the driven sprocket.

[0074] The speed fluctuation curve is then used as the input boundary condition for the drive sprocket assembly, and the load torque data is applied to the driven sprocket assembly and input into the established multibody dynamics model. After receiving these two time-dependent excitation signals, the multibody dynamics model conducts a time-domain solution process based on the structural topology, contact pair definitions, lubrication-evaporation-friction coupling parameters, and various correction functions. At each time step, the model utilizes numerical integration to solve the system's differential equations of motion while dynamically updating physical quantities such as contact force, friction damping, and meshing clearance, thereby capturing the state evolution of the chain system throughout the entire mission cycle.

[0075] The simulation output results include three key performance indicators: the first is the chain tension distribution, that is, the magnitude and transmission direction of the tension between each chain link, reflecting whether the chain is loose, skipping, or over-tensioning during the force application process; the second is the tensioner response behavior, which describes the displacement response, damping change, and elastic recovery capacity of the tensioner under dynamic disturbance conditions, and evaluates its buffering effect on chain tension fluctuations; the third is the system transmission error, that is, the instantaneous deviation between the angular displacement of the driving sprocket and the angular displacement of the driven sprocket, which is used to quantitatively describe the accuracy and stability of the chain drive.

[0076] Optional, in Figure 2 After step S201 of the illustrated embodiment, the following steps may be performed: The simulation results are evaluated to obtain simulation evaluation results. When the simulation evaluation results do not meet the preset evaluation requirements, the connection relationship and structural parameters are adjusted based on the simulation evaluation results until the simulation evaluation results meet the preset evaluation requirements and the evaluation is stopped.

[0077] Specifically, a systematic evaluation is first performed on the dynamic simulation results output from step S206. The simulation results include multiple performance indicators, such as chain tension distribution, tensioner response behavior, and system transmission error. The system determines these indicators using preset evaluation criteria, such as whether chain tension fluctuates within an allowable range, whether tensioner displacement exhibits saturation or hysteresis, and whether transmission error is below a set threshold. These preset evaluation requirements can be derived from national standards, enterprise specifications, or specific task performance requirements, and are typically provided as numerical ranges, limits, or statistical indicators (such as variance and maximum deviation).

[0078] When the evaluation finds that any one or more simulation results do not meet the preset evaluation requirements, the feedback adjustment stage is entered. At this time, the source of performance deviation is located in combination with the simulation evaluation results, and the connection relationship and structural parameters are adjusted in a targeted manner. The adjustment of the connection relationship includes but is not limited to changing the assembly method, contact type or pair type between components, such as replacing the sliding pair with a flexible connection pair to absorb dynamic impact, or optimizing the meshing angle between the chain link and the sprocket to improve the meshing efficiency. The adjustment of structural parameters includes component geometric dimensions (such as the number of sprocket teeth, chain link pitch), mass distribution, material stiffness, and lubrication distribution area, etc., with the aim of improving the system dynamic response through structural characteristics.

[0079] To achieve efficient and goal-oriented parameter adjustment, numerical solutions based on gradient optimization, genetic algorithms, or multi-objective optimization algorithms can be introduced to perform sensitivity analysis on the simulation evaluation results to identify the structural variables or connection relationships that most impact performance indicators. After adjustment, steps S204 to S206 are re-executed to update the 3D structural model, coupling matrix, and dynamic simulation process, forming a complete optimization cycle. This cycle continues until the simulation evaluation results meet all pre-defined evaluation requirements—i.e., stable chain tension distribution, smooth tensioner response, and transmission error within acceptable limits—at which point the system automatically terminates the iteration.

[0080] See also Figure 3 , is a schematic structural diagram of a multi-body dynamics simulation system for a chain system provided in an embodiment of the present application. A multi-body dynamics simulation system 300 for a chain system specifically includes: An acquisition module 301 is used to obtain the connection relationship between multiple target components in the chain system, the structural parameters of each target component, space environment parameters, mission parameters and the physical characteristics of the lubricating medium of the chain system under the space environment parameters; a correction module 302 is used to correct the structural parameters of each target component based on the space environment parameters to obtain the target structural parameters; a first determination module 303 is used to determine the friction characteristic indicators and motion degrees of freedom between multiple target components based on the target structural parameters and connection relationship; a first construction module 304 is used to construct a lubrication-volatility-friction coupling matrix between multiple target components based on the flow characteristics, physical characteristics, friction characteristic indicators, connection relationship and motion degrees of freedom of the lubricating medium; a second construction module 305 is used to construct a multi-body dynamics model based on the target structural parameters and the lubrication-volatility-friction coupling matrix; a simulation module 306 is used to obtain the speed fluctuation curve and load torque data corresponding to the mission parameters, and input the speed fluctuation curve and load torque data into the multi-body dynamics model to obtain the dynamic simulation results of the chain system, which include the chain tension distribution, tensioner response behavior and system transmission error of the chain system.

[0081] Optionally, the correction module 302 is specifically used to: calculate the thermal stress distribution of the target component during the temperature cycle process according to the temperature cycle parameters in the space environment parameters, and determine the thermal deformation of the target component based on the thermal stress distribution; obtain the mechanical property test data of the target component under different irradiation cumulative times according to the radiation parameters in the space environment parameters, and determine the material property change trend of the target component; establish a temperature-stress response curve of the target component based on the thermal deformation and the thermal stress distribution, and calibrate the thermal stress critical interval in the temperature-stress response curve; correct the thermal stress critical interval of the temperature-stress response curve according to the material property change trend to obtain a corrected response curve; determine the offset of the structural parameters of the target component according to the thermal stress critical interval in the corrected response curve, and correct the structural parameters of the target component based on the offset to obtain the target structural parameters.

[0082] Optionally, the determination module 303 is specifically used to: determine the contact point between the first target component and the second target component according to the target structure parameters and the connection relationship, the first target component and the second target component being any two target components among the multiple target components; determine the relative motion type between the first target component and the second target component based on the connection relationship, and determine the direction of the contact force between the first target component and the second target component at the contact point based on the relative motion type; obtain roughness data of each contact point, and determine the actual contact state according to the roughness data; determine the magnitude and direction of the friction force between the first target component and the second target component based on the actual contact state and the direction of the contact force, and generate a friction characteristic index; analyze the constraint type of the first target component and the second target component in the actual contact state based on the connection relationship, and identify the movable direction and rotation angle of the first target component and the second target component; determine the degree of freedom of motion of the first target component and the second target component according to the movable direction and the rotation angle.

[0083] Optionally, the system also includes a second determination module 307, which is specifically used to: construct a contact area distribution map of the contact area of the lubricating medium based on the actual contact state of the contact point, where the contact area is determined by the contact point; and determine the flow characteristics of the lubricating medium in each contact area based on the viscosity parameters and the direction of contact force in the physical properties.

[0084] Optionally, the first construction module 304 is specifically used to: determine the lubrication state type of the lubricating medium in each contact area based on the flow characteristics and the degrees of freedom of movement, the lubrication state types including fluid lubrication area, mixed lubrication area and boundary lubrication area; calculate the volatilization rate of the lubricating medium in each contact area according to the saturated vapor pressure parameter in the physical characteristics; determine the friction coefficient of each contact area based on the friction characteristic index; establish a mapping relationship between the lubrication state type and the friction coefficient based on the volatilization rate and the friction coefficient; obtain a three-dimensional structural model of the chain system; determine the spatial topological order of the target components in the chain system based on the connection relationship and the three-dimensional structural model; arrange the flow characteristics, volatilization rate and friction coefficient of the lubricating medium in each contact area in a spatial topological order to obtain a lubrication-volatilization-friction coupling matrix.

[0085] Optionally, the second construction module 305 is specifically used to: divide the target components into a driving sprocket component, a driven sprocket component, a chain component and a tensioner component based on the target structural parameters; determine the lubrication state parameters of the lubricating medium based on the flow characteristics in the lubrication-evaporation-friction coupling matrix; construct a meshing clearance correction function between the first category target components based on the lubrication state parameters, and the first category target components include the driving sprocket component, the driven sprocket component and the chain component; construct a friction damping change relationship of the tensioner component during the lubrication state change process based on the evaporation rate in the lubrication-evaporation-friction coupling matrix; analyze the friction coefficient change trend of the friction coefficient in the lubrication-evaporation-friction coupling matrix during the lubrication state change process, and establish a dynamic force transmission correction function between the second category target components during the meshing process based on the friction coefficient change trend, and the second category target components include the driving sprocket component and the chain component; obtain a multi-body dynamics model based on the meshing clearance correction function, the friction damping change relationship and the dynamic force transmission correction function.

[0086] Optionally, the system also includes an evaluation module 308, which is specifically used to: evaluate the simulation results to obtain simulation evaluation results; when the simulation evaluation results do not meet the preset evaluation requirements, adjust the connection relationship and structural parameters based on the simulation evaluation results, and stop the evaluation until the simulation evaluation results meet the preset evaluation requirements.

[0087] This embodiment also discloses an electronic device, referring to Figure 4The electronic device may include: at least one processor 401, at least one communication bus 402, a user interface 403, a network interface 404, and at least one memory 405. The communication bus 402 is used to enable communication between these components. The user interface 403 may include a display screen and a camera, and may optionally include a standard wired interface or a wireless interface. The network interface 404 may optionally include a standard wired interface or a wireless interface. The processor 401 may include one or more processing cores. The processor 401 utilizes various interfaces and circuits to connect various components within the server. It executes instructions, programs, code sets, or instruction sets stored in the memory 405, and accesses data stored in the memory 405 to perform various server functions and process data. Optionally, the processor 401 may be implemented in hardware using at least one of digital signal processing, field programmable gate arrays, and programmable logic arrays. The memory 405 may include either random access memory or read-only memory. Optionally, the memory 405 may include non-transitory computer-readable media. The memory 405 may be used to store instructions, programs, code, code sets, or instruction sets. The memory 405 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function, instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store data involved in the above-mentioned various method embodiments, etc.

[0088] exist Figure 4 In the electronic device shown, the user interface 403 is mainly used to provide an input interface for the user and obtain data input by the user; and the processor 401 can be used to call an application program stored in the memory 405 for a multi-body dynamics simulation method of a chain system. When executed by one or more processors 401, the electronic device executes one or more methods in the above-mentioned embodiments.

Claims

1. A multi-body dynamics simulation method for a chain system, characterized in that: Applied to a multi-body dynamics simulation platform, the method includes: Acquire connection relationships between multiple target components in a chain system, structural parameters of each target component, space environment parameters, mission parameters, and physical properties of a lubricating medium of the chain system under the space environment parameters; Correcting the structural parameters of each target component based on the space environment parameters to obtain target structural parameters; Determining friction characteristic indicators and degrees of freedom of movement between a plurality of target components based on the target structural parameters and the connection relationship; Constructing a lubrication-evaporation-friction coupling matrix between a plurality of target components based on the flow characteristics of the lubricating medium, the physical characteristics, the friction characteristic index, the connection relationship, and the degree of freedom of movement; Constructing a multi-body dynamics model according to the target structural parameters and the lubrication-volatility-friction coupling matrix; Obtain a speed fluctuation curve and load torque data corresponding to the task parameters, input the speed fluctuation curve and the load torque data into the multi-body dynamics model, and obtain a dynamic simulation result of the chain system, wherein the dynamic simulation result includes the chain tension distribution, tensioner response behavior and system transmission error of the chain system.

2. The method according to claim 1, characterized in that The step of correcting the structural parameters of each target component based on the space environment parameters to obtain target structural parameters specifically includes: calculating a thermal stress distribution of the target component during the temperature cycling process according to a temperature cycling parameter in the space environment parameter, and determining a thermal deformation amount of the target component based on the thermal stress distribution; Acquiring mechanical property test data of the target component at different cumulative irradiation times based on the radiation parameters in the space environment parameters, and determining a material property change trend of the target component; Establishing a temperature-stress response curve of the target component based on the thermal deformation and the thermal stress distribution, and calibrating a thermal stress critical interval in the temperature-stress response curve; According to the change trend of the material properties, the thermal stress critical interval of the temperature-stress response curve is modified to obtain a modified response curve; According to the critical interval of thermal stress in the modified response curve, an offset of the structural parameter of the target component is determined, and the structural parameter of the target component is modified based on the offset to obtain target structural parameters.

3. The method according to claim 1, characterized in that The determining of the friction characteristic index and the degree of freedom of movement between the plurality of target components based on the target structural parameters and the connection relationship specifically includes: determining, according to the target structure parameters and the connection relationship, a contact point between a first target component and a second target component, where the first target component and the second target component are any two target components among the plurality of target components; Determining a relative motion type between the first target component and the second target component based on the connection relationship, and determining a direction of a contact force between the first target component and the second target component at the contact point based on the relative motion type; Acquiring roughness data of each of the contact points, and determining an actual contact state based on the roughness data; determining, based on the actual contact state and the direction of the contact force, a magnitude and a direction of the friction force between the first target component and the second target component, and generating a friction characteristic index; Analyzing the constraint type of the first target component and the second target component in the actual contact state based on the connection relationship, and identifying the movable direction and rotation angle of the first target component and the second target component; The degrees of freedom of movement of the first target component and the second target component are determined according to the movable direction and the rotation angle.

4. The method according to claim 3, characterized in that Before constructing the lubrication-evaporation-friction coupling matrix between the plurality of target components based on the flow characteristics, the physical characteristics, the friction characteristic index, the connection relationship, and the degrees of freedom of motion of the lubricating medium, the method further includes: constructing a contact area distribution map of a contact area of the lubricating medium based on the actual contact state of the contact point, the contact area being determined by the contact point; The flow characteristics of the lubricating medium in each of the contact areas are determined according to the viscosity parameters in the physical characteristics and the direction of action of the contact force.

5. The method according to claim 4, characterized in that The step of constructing a lubrication-volatility-friction coupling matrix between the plurality of target components based on the flow characteristics, the physical characteristics, the friction characteristic index, the connection relationship, and the degree of freedom of movement of the lubricating medium specifically includes: determining a lubrication state type of the lubricating medium in each of the contact areas based on the flow characteristics and the degrees of freedom of movement, wherein the lubrication state types include a fluid lubrication area, a mixed lubrication area, and a boundary lubrication area; Calculating the volatilization rate of the lubricating medium in each of the contact areas according to the saturated vapor pressure parameter in the physical properties; determining a friction coefficient for each contact area based on the friction characteristic index; Based on the volatilization rate and the friction coefficient, establishing a mapping relationship between the lubrication state type and the friction coefficient; obtaining a three-dimensional structural model of the chain system; Determining a spatial topological order of the target components in the chain system based on the connection relationship and the three-dimensional structure model; The lubrication medium flow characteristics, volatilization rate and friction coefficient of each contact area are arranged according to the spatial topological order to obtain a lubrication-volatilization-friction coupling matrix.

6. The method according to claim 5, characterized in that The multi-body dynamics model is constructed according to the target structural parameters and the lubrication-volatility-friction coupling matrix, specifically comprising: Based on the target structural parameters, the target assembly is divided into a driving sprocket assembly, a driven sprocket assembly, a chain assembly and a tensioner assembly; determining lubrication state parameters of the lubricating medium based on the flow characteristics in the lubrication-volatility-friction coupling matrix; constructing a meshing clearance correction function between target components of a first category based on the lubrication state parameter, wherein the target components of the first category include the driving sprocket assembly, the driven sprocket assembly, and the chain assembly; constructing a friction damping variation relationship of the tensioner assembly during a lubrication state variation process based on the volatilization rate in the lubrication-volatilization-friction coupling matrix; analyzing a friction coefficient variation trend of the friction coefficient in the lubrication-volatility-friction coupling matrix during a lubrication state variation process, and establishing a dynamic force transmission correction function between second-category target components during a meshing process based on the friction coefficient variation trend, the second-category target components including the drive sprocket assembly and the chain assembly; The multi-body dynamics model is obtained based on the meshing clearance correction function, the friction damping change relationship and the dynamic force transmission correction function.

7. The method according to claim 1, characterized in that After obtaining the dynamic simulation results of the chain system, the method further includes: The simulation results are evaluated to obtain simulation evaluation results. When the simulation evaluation results do not meet the preset evaluation requirements, the connection relationship and the structural parameters are adjusted based on the simulation evaluation results until the simulation evaluation results meet the preset evaluation requirements and the evaluation is stopped.

8. A multi-body dynamics simulation system for a chain system, characterized in that: include: an acquisition module, configured to acquire connection relationships between a plurality of target components in a chain system, structural parameters of each target component, space environment parameters, mission parameters, and physical properties of a lubricating medium of the chain system under the space environment parameters; a correction module, configured to correct the structural parameters of each target component based on the space environment parameters to obtain target structural parameters; A first determining module is configured to determine friction characteristic indices and degrees of freedom of motion between a plurality of target components based on the target structural parameters and the connection relationship; A first construction module is configured to construct a lubrication-evaporation-friction coupling matrix between a plurality of target components based on the flow characteristics of the lubricating medium, the physical characteristics, the friction characteristic index, the connection relationship, and the degree of freedom of movement; A second construction module is used to construct a multi-body dynamics model according to the target structural parameters and the lubrication-volatility-friction coupling matrix; A simulation module is used to obtain a speed fluctuation curve and load torque data corresponding to the task parameters, input the speed fluctuation curve and the load torque data into the multi-body dynamics model, and obtain a dynamic simulation result of the chain system, wherein the dynamic simulation result includes the chain tension distribution, tensioner response behavior and system transmission error of the chain system.

9. An electronic device, characterized in that: include: one or more processors and memory; The memory is coupled to the one or more processors, and is configured to store computer program codes, where the computer program codes include computer instructions. The one or more processors call the computer instructions to enable the electronic device to execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium comprising instructions, characterized in that: When the instructions are executed on an electronic device, the electronic device is caused to execute the method according to any one of claims 1 to 7.

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