A method for coupling modeling of tractor integrated drive system multi-body dynamics associated with tire-soil-machine interaction

Abstract

This invention relates to the field of agricultural machinery technology, specifically to a multibody dynamics coupling modeling method for a tractor's integrated transmission system that integrates tire-soil-implement interaction. The method includes constructing an initial multibody dynamics model comprising the engine, main and auxiliary gearboxes, transfer case, front and rear drive axles, and tires. By incorporating soil hardness, tire pressure, and implement parameters, and introducing tire-soil and implement-soil interaction models, the mechanical coupling between tires, implements, and soil is achieved. Through high-precision numerical solutions, the traction efficiency and energy consumption indicators of the tractor under different soil conditions and operating modes are obtained, thus providing theoretical support for tractor energy efficiency optimization and operating strategies. This invention, through global coupling modeling and high-precision simulation, can effectively improve the traction efficiency of the tractor transmission system, reduce energy consumption, and provide quantitative basis for optimized design, possessing broad engineering application value.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery technology, and in particular to a multibody dynamics coupling modeling method for an integrated tractor transmission system that relates to the interaction between tires, soil, and implements. Background Technology

[0002] With the continuous improvement of agricultural mechanization, tractors, as the core equipment of agricultural machinery power systems, directly affect the traction efficiency, energy consumption, and operational stability of the entire machine through the performance of their transmission systems. Traditional tractor transmission systems typically consist of an engine, gearbox, drive shaft, and tires, transmitting power to the ground via a drive chain to achieve traction. However, in actual farmland environments, the tractor's operating state is not only affected by its mechanical structure and transmission characteristics but also by the combined effects of complex soil conditions and varying implement loads. The physical properties of the soil (including hardness, moisture content, and internal friction angle) and the operating parameters of the implements (including weight, penetration depth, and type) significantly alter the force state and energy transfer patterns of the transmission system.

[0003] In existing technologies, research on tractor transmission systems mostly focuses on individual components or local dynamic processes, typically employing simplified rigid body models or semi-empirical mechanical models for analysis, failing to achieve multi-body coupling descriptions at the vehicle-wide level. Traditional tire models mostly consider only the contact characteristics between the tire and the rigid ground, making it difficult to accurately reflect the settlement, slippage, and shear effects of the tire under soft soil conditions; modeling of implement-soil interactions is mostly based on empirical drag coefficients, lacking a dynamic linkage mechanism with the tractor transmission system. Furthermore, existing studies generally do not couple the transmission chain components such as the engine, gearbox, and drive shaft with the external operating environment in simulation, resulting in significant deviations in the calculated traction power, energy consumption, and efficiency, making it difficult to realistically reflect the dynamic response process of the tractor under different soil and operating conditions. Summary of the Invention

[0004] This invention provides a multibody dynamics coupling modeling method for the integrated transmission system of a tractor that relates tires, soil, and implements. This method enables unified modeling and simulation of the engine, transmission system, tires, soil, and implement workload, achieving accurate modeling, coupling analysis, and energy efficiency evaluation of the overall dynamic system of the tractor.

[0005] A multibody dynamics coupling modeling method for a tractor integrated drive system involving tire-soil-implementation interaction includes the following steps: S1: Construct an initial multibody dynamics model of the tractor's integrated transmission system. The initial multibody dynamics model includes the geometric and inertial parameters of the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires. S2: Based on the initial multibody dynamics model, a tire-soil interaction model is introduced, and the tire-soil interaction force is calculated using soil hardness parameters and tire pressure parameters. S3: Based on the tire-soil interaction force calculated in S2, a machine-soil interaction model is introduced, and the machine-soil interaction force is calculated using machine weight parameters and soil type parameters; S4: Integrate the tire-soil interaction force and the implement-soil interaction force into the initial multibody dynamics model to generate an overall coupled multibody dynamics model; S5: Solve the overall coupled multibody dynamics model to obtain the dynamic response data of the transmission system; S6: Based on the dynamic response data, analyze the tractor's traction efficiency and energy consumption indicators.

[0006] Optionally, S1 includes: S11: Based on the tractor's design drawings and 3D model, obtain the geometric parameters of the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires. The geometric parameters include the external dimensions, mass attributes, spatial installation position, and connection relationship of each component in the whole vehicle, thereby establishing the geometric parameters of the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires. S12: Based on the geometric parameters of the engine, main and auxiliary transmissions, transfer case, front drive axle, rear drive axle, and tires established in S11, the inertial parameters of the engine, main and auxiliary transmissions, transfer case, front drive axle, rear drive axle, and tires are determined by calculation or experimental measurement. The inertial parameters include the mass, center of mass position, and moment of inertia about each component. S13: The geometric parameters of the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires obtained in S11, as well as the inertial parameters of the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires obtained in S12, are imported into the multibody dynamics simulation software as component attributes. Based on the spatial installation position and connection relationship of each component, corresponding kinematic pairs and constraints are added. Finally, a multibody dynamics initial model of the tractor's integrated transmission system, including the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires, is constructed.

[0007] Optionally, in S12, the inertial parameters of the engine, gearbox, drive shaft, and tires are determined by calculation or experimental measurement. Specifically, the inertial parameters of each component are automatically calculated and output based on the geometric parameters of the engine, gearbox, drive shaft, and tires established in S11 using the mass attribute analysis function of the 3D modeling software.

[0008] Optionally, S2 includes: S21: Based on the geometric parameters and spatial pose of the tire in the initial model of the multibody dynamics, determine the geometric characteristics of the contact area between the tire and the soil, and obtain the soil hardness parameters obtained by field measurement or soil database query, as well as the tire pressure parameters determined by tire pressure sensor measurement or design specifications. S22: Based on the soil hardness and tire pressure parameters determined in S21, select and call the tire-soil interaction model constructed based on the Bekker pressure-settlement relationship and the Janosi shear stress-displacement relationship. S23: The soil hardness parameters and tire pressure parameters obtained in S21, as well as the geometric parameters and motion state of the tire in the initial multibody dynamics model, are used as input variables and substituted into the tire-soil interaction model called in S22 to calculate the normal pressure distribution and tangential shear stress distribution acting on the tire ground surface. S24: Integrate the normal pressure distribution and tangential shear stress distribution on the tire ground surface obtained from S23 within the contact area defined by the tire-soil interaction model to obtain the total tire-soil interaction force acting on the tire. This total tire-soil interaction force includes the vertical support force, longitudinal traction force and lateral force in three-dimensional space. S25: The total tire-soil interaction force calculated in S24 is used as an external load and applied to the corresponding tire component in the initial multibody dynamics model to complete the mechanical coupling between the tire-soil interaction model and the initial multibody dynamics model.

[0009] Optionally, in S21, the soil hardness parameters include soil cohesion, soil internal friction angle, and soil deformation modulus.

[0010] Optionally, S3 includes: S31: Based on the tire-soil interaction force calculated by S2, combined with the position of the tractor's drawbar connection point, the traction force of the implement hook acting on the drawbar connection point is calculated through static equilibrium relationship, and the implement weight parameters obtained by design manual or direct weighing and the soil type parameters obtained by on-site identification or soil database query are obtained. S32: Based on the soil type parameters obtained in S31, select and call the implement-soil interaction model applicable to the soil type parameters. The implement-soil interaction model is a mathematical model based on classical soil mechanics theory for predicting the working resistance of the working parts of the implement under specific soil type parameters. S33: Take the implement weight parameters obtained in S31 and the implement hook traction force calculated in S31 as key input variables, substitute them into the implement-soil interaction model called in S32, and calculate the total working resistance of the implement working parts during the tillage process, that is, the implement-soil interaction force. S34: The implement-soil interaction force calculated in S33 is applied as an external load to the tractor's traction frame connection point in the multibody dynamics initial model in the form of a reaction force, thereby completing the mechanical coupling between the implement-soil interaction model and the multibody dynamics initial model.

[0011] Optionally, the soil type parameters in S31 include soil bulk density, soil moisture content, and soil firmness.

[0012] Optionally, S4 includes: S41: Confirm that the tire-soil interaction force calculated by S2 has been applied as an external load to the tire component of the multibody dynamics initial model, and at the same time confirm that the implement-soil interaction force calculated by S3 has been applied as an external load to the traction frame connection point of the multibody dynamics initial model, thereby completing the application of all external loads and forming a multibody dynamics initial model containing all external loads. S42: Based on the multibody dynamics initial model containing all external loads formed in S41, establish the mechanical coupling relationship between the tire-soil interaction force and the implement-soil interaction force. This mechanical coupling relationship dynamically links the tire-soil interaction force acting on the tire and the implement-soil interaction force acting on the traction frame through the motion and force balance of the tractor body, forming a closed-loop force transmission system. S43: Based on the mechanical coupling relationship established in S42, verify the correctness and completeness of the kinematic pairs and constraints between the components, the application of all external loads, and the force flow transmission path in the initial multibody dynamics model containing all external loads. Finally, generate an overall coupled multibody dynamics model that can accurately reflect the interaction between tire, soil, and machinery.

[0013] Optionally, S5 includes: S51: Set the solution parameters for the overall coupled multibody dynamics model generated in S4, including simulation time, integration step size and numerical integration algorithm, to form the overall coupled multibody dynamics model to be solved; S52: Based on the solution parameters set in S51, the solver of the multibody dynamics simulation software is used to perform numerical integration calculations on the overall coupled multibody dynamics model to be solved, and the original response data of the system in the time domain is obtained. S53: Extract specific physical quantities related to the transmission system from the raw response data obtained in S52, including engine output torque, gearbox shaft load and drive shaft speed, to generate the dynamic response data of the transmission system.

[0014] Optionally, S6 includes: S61: Based on the dynamic response data obtained in S5, extract the traction force of the implement hook acting on the tractor drawbar connection point and the actual driving speed of the tractor, calculate the traction power, extract the engine output torque and speed, calculate the engine output power, and then calculate the tractor traction efficiency by the ratio of traction power to engine output power. S62: Based on the traction efficiency calculated in S61 and the engine fuel consumption rate or motor input current extracted from the dynamic response data, combined with the total simulation time, the total energy consumption index of the tractor in the process of completing a specific task is calculated. S63: Combining the traction efficiency calculated in S61 and the total energy consumption index calculated in S62, a quantitative comparative analysis of the traction performance and economy of the tractor's integral transmission system under different soil parameters and implement operating parameters is conducted, generating a traction efficiency and energy consumption index analysis report for evaluating and optimizing system design.

[0015] The beneficial effects of this invention are: This invention, through a systematic approach, couples the transmission chain consisting of the engine, gearbox, drive shaft, and tires with the dual external environmental interactions of tire-soil and implement-soil, establishing a complete integrated multibody dynamics model of the transmission system. By accurately extracting geometric and inertial parameters, a tire-soil interaction model based on the Bekker pressure-settlement relationship and the Janosi shear stress-displacement relationship is introduced. Furthermore, an implement-soil interaction model based on soil cutting theory and bearing characteristics is introduced, achieving a unified description of multiple physics fields, multiple forces, and multiple transmission paths.

[0016] This invention, through the high-precision solution steps of S5, employs the GSTIFF integrator, WSTIFF integrator, or Runge-Kutta method for numerical integration, and combines it with the multibody dynamics solver of ADAMS simulation software to achieve high-precision time-domain response calculation of nonlinear coupled systems. It can acquire key response parameters such as engine output torque, transmission shaft load, drive shaft speed, transmission gear meshing force, and tire slip ratio in real time, comprehensively reflecting the dynamic changes of the transmission system under complex operating conditions.

[0017] This invention, based on dynamic response data from simulation output, constructs a two-dimensional analysis system for traction efficiency and total energy consumption. It calculates traction power by multiplying the hook traction force by the travel speed, and then combines this with engine output power to calculate traction efficiency in real time. Simultaneously, it calculates total energy consumption for different operating cycles based on fuel consumption rate or motor input current. This not only provides quantitative basis for the structural design, power matching, and energy efficiency optimization of tractor transmission systems, but also provides theoretical guidance for selecting operating parameters under different soil conditions, demonstrating significant application value and promotional significance. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the method flow according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the S2 process in an embodiment of the present invention. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0021] like Figures 1-2 As shown, a multibody dynamics coupling modeling method for a tractor's integrated transmission system that relates tire-soil-implementation interaction includes the following steps: S1: Construct the initial multibody dynamics model of the tractor's integrated transmission system. The initial multibody dynamics model includes the geometric and inertial parameters of the engine, gearbox, drive shaft, and tires, specifically: S11: Based on the tractor's design drawings and 3D model, obtain the geometric parameters of the engine, main and auxiliary gearboxes, transfer case, front and rear drive axles, and wheels, specifically: Based on the tractor's structural design drawings and its digital prototype model, three-dimensional parametric modeling of the tractor's main transmission components was performed.

[0022] In practice, a digital prototype model of the tractor is created using 3D modeling software, specifically SolidWorks.

[0023] During the process of establishing the digital prototype model, the engine, main and auxiliary gearboxes, transfer case, front and rear drive axles and wheels were precisely modeled to ensure that the geometry, assembly relationship and spatial position were consistent with the actual vehicle.

[0024] By calling the model attribute extraction module of the 3D modeling software, the geometric parameters of the engine, main and auxiliary transmissions, transfer case, front drive axle, rear drive axle, and wheels are extracted one by one.

[0025] The geometric parameters include the external dimensions of each component and the spatial installation position and connection relationship of each component in the vehicle.

[0026] in: The external dimensions include the length, width, and height of the engine block; the main wheelbase, gear center distance, and housing dimensions of the main and auxiliary gearboxes; the center distance between the input and output flanges and the gear meshing distance of the transfer case; the axle housing width, axle tube diameter, and differential cavity dimensions of the front and rear drive axles; and the radius and width of the wheels. The spatial installation location and connection relationship include the mounting point coordinates of the engine and main transmission, the flange connection coordinates of the main and auxiliary transmissions and the transfer case, the output connection point coordinates of the transfer case and the front and rear drive axles, and the assembly reference point coordinates of the drive axle and the wheels.

[0027] All the above geometric parameters are recorded in three-dimensional coordinates and automatically output by SolidWorks as data format files (such as STEP or XML format) that can be imported into multibody dynamics simulation software, forming geometric parameter files for the engine, main and auxiliary transmissions, transfer case, front drive axle, rear drive axle and wheels, providing accurate geometric input for subsequent dynamics modeling.

[0028] S12: Based on the geometric parameters established in S11, determine the inertial parameters of the engine, main and auxiliary transmissions, transfer case, front and rear drive axles, and wheels, specifically: Using the digital prototype model established in S11, the inertial parameters of each transmission component are automatically calculated through the mass attribute analysis function built into the 3D modeling software.

[0029] Specifically, it includes: Mass analysis is performed on the geometric parameters of the engine to calculate the total mass, center of mass position, and triaxial moment of inertia about the center of mass. Mass analysis is performed on the geometric parameters of the main and auxiliary gearboxes to calculate the total mass, center of mass position, and moment of inertia of the main and auxiliary gearboxes. Mass analysis is performed on the geometric parameters of the transfer case to calculate its total mass, center of mass position, and moment of inertia. Mass analysis is performed on the geometric parameters of the front and rear drive axles to calculate their total mass, center of mass position, and moment of inertia. Mass analysis is performed on the geometric parameters of the wheel to calculate its total mass, center of mass position, and moment of inertia about the center of mass.

[0030] The analysis results are automatically output by the 3D modeling software and stored in the form of standardized data files to ensure that the inertial parameters can be imported into the multibody dynamics simulation platform without loss.

[0031] During the calculation process, all components use density parameters consistent with those of the actual vehicle materials, the accuracy of the geometric model is controlled within the design tolerance range, and the calculation error of the inertial parameters is controlled within 1%.

[0032] After this step is completed, complete inertial parameter files for the engine, main and auxiliary transmissions, transfer case, front and rear drive axles, and wheels are obtained, providing a reliable dynamic property basis for subsequent dynamic simulations.

[0033] S13: Import multibody dynamics simulation software to construct an initial multibody dynamics model including the engine, main and auxiliary transmissions, transfer case, front and rear drive axles, and wheels. Specifically: Import the geometric parameter file obtained in S11 and the inertial parameter file obtained in S12 into the multibody dynamics simulation software to establish the initial multibody dynamics model of the tractor's overall transmission system.

[0034] The multibody dynamics simulation software is ADAMS.

[0035] In practice, a global coordinate system is first established in ADAMS as the reference coordinate system for the whole vehicle. Then, the geometric models and inertial parameter files of the engine, main and auxiliary transmissions, transfer case, front drive axle, rear drive axle and wheels are imported in sequence, and three-dimensional spatial positioning is performed according to the actual assembly relationship.

[0036] The establishment of assembly constraints includes: Establish a rotating joint constraint between the engine and the main and auxiliary gearboxes to ensure that the engine output shaft and the gearbox input shaft are coaxially connected and to achieve torque transmission. A fixed pair connection is established between the main and auxiliary gearboxes and the transfer case to achieve input torque splitting; Universal joint constraints are established between the transfer case and the front and rear drive axles to compensate for angular deviations and achieve synchronous power transmission. Establish a rotating pair connection between the front and rear drive axles and the wheels to ensure that the angular velocity of the wheels is consistent with the output angular velocity of the drive axle. Contact constraints are applied between the wheel and the ground to provide a dynamic interface for the subsequent introduction of a tire-soil interaction model.

[0037] Furthermore, local inertial coordinate systems are established at the centroids of each component, and the transmission system topology is defined in the software to ensure that loads and torques are correctly transmitted along the transmission path. After verifying the integrity of the constraints through topology consistency verification and kinematic pair detection, an initial multibody dynamics model including the engine, main and auxiliary gearboxes, transfer case, front and rear drive axles, and wheels is generated.

[0038] The model has complete geometric, inertial and constraint information, providing basic input conditions for subsequent tire-soil-machine interaction modeling.

[0039] S2: Based on the initial multibody dynamics model, a tire-soil interaction model is introduced. The tire-soil interaction force is calculated using soil hardness and tire pressure parameters. Specifically: S21: Based on the tire's geometric parameters and spatial pose in the initial multibody dynamics model, determine the geometric characteristics of the contact area between the tire and the soil, and obtain soil hardness parameters obtained through field measurements or soil database queries, as well as tire pressure parameters measured by tire pressure sensors or determined by design specifications. The specific steps are as follows: By extracting the radius, tire width, and attitude angle relative to the ground from the tire's geometric parameters, and combining the vertical deformation of the tire under vehicle load, the geometric contact analysis algorithm is used to determine the contact area between the tire and the soil, as well as the major and minor axes of the contact ellipse.

[0040] After determining the geometric characteristics of the contact area, soil hardness parameters and tire pressure parameters are obtained.

[0041] Soil hardness parameters include soil cohesion, soil internal friction angle, and soil deformation modulus.

[0042] Soil cohesion was obtained through soil penetration tests or static cone penetration tests, soil internal friction angle was determined through direct shear tests, and soil deformation modulus was determined through indoor triaxial compression tests; the above data can also be determined by looking up tables in a standardized soil database.

[0043] Tire pressure parameters are measured in real time using tire pressure sensors or set according to the manufacturer's design specifications. By pairing and analyzing soil hardness parameters with tire pressure parameters, the basic environmental input for the current tire-soil interaction is obtained, providing input conditions for subsequent model calls and mechanical calculations.

[0044] S22: Based on the soil hardness and tire pressure parameters determined in S21, select and call the tire-soil interaction model constructed based on the Bekker pressure-settlement relationship and the Janosi shear stress-displacement relationship. The steps are as follows: The Bekker pressure-sinking relationship describes the nonlinear relationship between the normal pressure at any point on the tire contact patch and the sinking depth. Its expression is: ; in, The normal pressure on the tire's contact patch. For tire width, This refers to the tire sink depth. The subsidence coefficient is related to soil cohesion. The settlement coefficient is related to the soil internal friction angle. Soil deformation index; The Janosi shear stress-displacement relationship is used to describe the relationship between tangential shear stress and shear displacement between a tire and the soil. Its expression is: ; in, For shear stress, For soil cohesion, For normal stress, The internal friction angle of the soil. This is the shear displacement. This is the shear modulus.

[0045] The specific model parameters of the tire-soil interaction model include soil cohesion, internal friction angle, deformation modulus, shear deformation modulus, and tire width and diameter. During model calculation, the system automatically calls the corresponding parameter set according to different soil types and tire specifications to ensure that the pressure and shear response output by the model conforms to actual ground conditions.

[0046] S23: Using the soil hardness and tire pressure parameters obtained in S21, as well as the tire's geometric parameters and motion state in the initial multibody dynamics model, as input variables, and substituting them into the tire-soil interaction model called in S22 for calculation, the steps are as follows: The motion state of the tire in the initial multibody dynamics model includes the tire's instantaneous translational velocity, instantaneous rotational angular velocity, and slip ratio relative to the soil.

[0047] During the simulation calculation, based on the contact point position between the tire and the ground, the instantaneous settlement and slippage of each contact unit are obtained in real time. The normal pressure distribution is calculated using the Bekker pressure-settlement relationship, and the tangential shear stress distribution is calculated using the Janosi shear stress-displacement relationship.

[0048] The calculation process uses a discrete contact area division method, which divides the contact surface between the tire and the soil into multiple micro-units. The normal pressure and tangential stress are calculated for each unit, and finally the normal pressure distribution map and tangential shear stress distribution map of the entire tire contact surface are obtained.

[0049] The above distribution data provides the input basis for subsequent integral calculations.

[0050] S24: Integrate the normal pressure distribution and tangential shear stress distribution on the tire contact surface obtained from S23 within the contact area defined by the tire-soil interaction model to obtain the total tire-soil interaction force acting on the tire. The steps are as follows: The integration process employs numerical integration methods, accumulating the calculations on discrete elements of the contact surface using Gaussian or trapezoidal integration. The final calculated total tire-soil interaction force includes the vertical support force, longitudinal traction force, and lateral force in three-dimensional space.

[0051] in: Vertical support force is used to balance the vehicle's gravitational load; Longitudinal traction force is used to characterize the traction performance provided by the drive wheels; Lateral forces are used to describe the lateral stability of a vehicle under steering or asymmetric load conditions.

[0052] The results are output in the form of a time series, providing dynamic external force inputs for multibody dynamics systems.

[0053] S25: Apply the total tire-soil interaction force calculated in S24 as an external load to the corresponding tire component in the initial multibody dynamics model to achieve mechanical coupling between the tire-soil interaction model and the initial multibody dynamics model. The steps are as follows: When applying load, the vertical support force, longitudinal traction force and lateral force are decomposed into the local coordinate system of the tire in vector form and connected to the force matrix of the multibody dynamics solver.

[0054] To ensure computational stability, a damping term is introduced during the application of external loads to suppress high-frequency oscillations and improve simulation convergence.

[0055] Ultimately, the tire-soil interaction model and the initial multibody dynamics model form a complete mechanically coupled system.

[0056] S3: Based on the tire-soil interaction force calculated in S2, an implement-soil interaction model is introduced. The implement-soil interaction force is calculated using implement weight parameters and soil type parameters. Specifically: S31: Based on the tire-soil interaction force calculated in S2, and combined with the location of the tractor's drawbar connection point, the traction force of the implement hook acting on the drawbar connection point is calculated using static equilibrium relationships. The implement weight parameters obtained from the design manual or direct weighing, and the soil type parameters obtained through on-site identification or soil database queries are also acquired. The steps are as follows: The three-dimensional coordinates of the tractor's rear drawbar connection point are extracted using multibody dynamics simulation software. Based on the balance equation between the driving force and the ground reaction force in the transmission system, the magnitude and direction of the implement hook traction force borne by the drawbar connection point are calculated.

[0057] The following static equilibrium expression is used in the calculation: ; in, For tire traction, For the traction force of the machine hook, For vertical support force, Given the total weight of the vehicle, the traction force of the implement hook can be calculated using the above formula. The instantaneous change value.

[0058] Subsequently, the weight parameters of the equipment and the soil type parameters were obtained.

[0059] The weight parameters of the implements are measured directly by the tractor-trailer weighing device or determined based on the static load weight data provided in the implement design manual.

[0060] Soil type parameters include soil bulk density, soil moisture content, and soil firmness.

[0061] Soil bulk density was obtained by ring sampler method, soil moisture content was determined by oven drying method, and soil firmness was measured by penetration soil hardness tester; if on-site conditions are limited, typical parameter values ​​can be determined by soil database query and regional interpolation method.

[0062] Finally, the traction force of the implement hook, the weight parameters of the implement, and the soil type parameters are used as input variables for subsequent implement-soil interaction modeling.

[0063] S32: Based on the soil type parameters obtained in S31, select and call the equipment-soil interaction model applicable to that soil type parameter. The steps are as follows: The implement-soil interaction model is a mathematical model based on classical soil mechanics theory used to predict the working resistance of implement components under specific soil type parameters.

[0064] In practice, when the soil type parameter is characterized as cohesive soil or clay loam, the plowshare resistance model based on soil cutting theory is invoked; when the soil type parameter is characterized as sandy loam or medium loam, the disc plow resistance model based on bearing characteristics is invoked.

[0065] The plowshare resistance model is based on the theory of passive soil fracturing, and its total resistance calculation formula is as follows: ; in, To reduce the working resistance of the plowshare, For soil cohesion, For vertical pressure, The internal friction angle of the soil. This represents the cutting area of ​​the plow body. This is a resistance correction factor related to the machine's operating speed.

[0066] The disk plow resistance model is based on the principle of superposition of normal stress and tangential shear stress distribution on the bearing surface, and its calculation formula is as follows: ; in, This provides resistance to the operation of the disc plow. The diameter of the disk. For soil bulk density, For the round disc to be embedded in the corner, For soil cohesion, , This is an empirical coefficient, determined by soil compaction and moisture content calibration.

[0067] Through the above model selection and calculation framework, different resistance models can be adaptively called according to soil type parameters to ensure that the calculated resistance of the equipment matches the actual working conditions.

[0068] S33: Using the implement weight parameters obtained in S31 and the implement hook traction force calculated in S31 as key input variables, substitute them into the implement-soil interaction model called in S32 to calculate the total working resistance experienced by the working parts of the implement during tillage, i.e., the implement-soil interaction force. The steps are as follows: During the calculation, the weight parameter of the machine is used. traction force of hooking with machinery Input the model, and calculate the force distribution of each working component under different depths and embedment angles by using the force balance relationship within the model.

[0069] The working parts of the implement are plowshares, rotary tillers, or furrow openers.

[0070] For plowshare-type implements, calculate the resultant force of the active earth pressure and passive reaction force on its cutting surface; For rotary tillers, the dynamic load component during the rotary cutting process is considered, and the resistance calculation results are corrected by the angular velocity correction coefficient. For trenching tools, calculate the frictional force and normal pressure distribution between the blades and the trench wall, and then obtain the total interactive resistance.

[0071] The final obtained implement-soil interaction force is the total resistance vector of the implement in the three-dimensional coordinate system. Its direction is opposite to the tractor traction direction, and its magnitude is positively correlated with the soil type parameters and the depth of the implement in the soil.

[0072] The calculation results are output in the form of time steps, providing input data for the application of reaction force in step S34.

[0073] S34: The implement-soil interaction force calculated in S33 is applied as a reaction force as an external load to the tractor's traction frame connection point in the initial multibody dynamics model, thereby achieving mechanical coupling between the implement-soil interaction model and the initial multibody dynamics model. The steps are as follows: When applying load, the interaction force between the implement and the soil is decomposed into components along the longitudinal, lateral, and vertical directions of the vehicle according to the three-dimensional force decomposition principle, and applied to the local coordinate system of the corresponding node of the traction frame connection point.

[0074] To ensure the stability of the coupled calculation, a force feedback module is introduced simultaneously when the reaction force is applied, so that the force changes of the tractor traction frame affect the dynamic response of the transmission system in real time.

[0075] During the coupled simulation solution process, the interaction force between the implement and the soil and the interaction force between the tire and the soil act together on the multibody dynamics system, forming a complete "tractor-tire-implement-soil" four-element coupled dynamics model.

[0076] This model can reveal the real-time impact of changes in implement resistance on tractor traction efficiency, energy consumption, and dynamic stability, providing input conditions for the subsequent S4 step of the overall coupled dynamic response analysis.

[0077] S4: Integrate the tire-soil interaction force and the implement-soil interaction force into the initial multibody dynamics model to generate a holistic coupled multibody dynamics model, specifically: S41: Confirm that the tire-soil interaction force calculated by S2 has been applied as an external load to the tire component of the initial multibody dynamics model, and simultaneously confirm that the implement-soil interaction force calculated by S3 has been applied as an external load to the traction frame connection point of the initial multibody dynamics model, thus completing the application of all external loads. The steps are as follows: In the multibody dynamics simulation software ADAMS, the vertical support force, longitudinal traction force and lateral force of the tire-soil interaction force are first applied to each tire contact point through the force vector input interface; each tire node is bound to a local coordinate system to ensure that the direction of the external force is consistent with the tire attitude.

[0078] Subsequently, the reaction force of the implement-soil interaction force is applied as a three-dimensional force vector to the tractor body's drawbar connection point, which coincides with the geometric constraint node of the traction mechanism to maintain the accuracy of the load transfer path.

[0079] All external loads are applied synchronously via time steps. That is, within each simulation time step, the tire-soil interaction force and the implement-soil interaction force are updated synchronously based on the calculation results of their respective models, achieving time-varying load input. Through this method, a multibody dynamics initial model incorporating all external loads is formed, providing a complete input foundation for subsequent mechanical coupling solutions.

[0080] S42: Based on the multibody dynamics initial model formed in S41, which includes all external loads, the mechanical coupling relationship between tire-soil interaction force and implement-soil interaction force is established, specifically: This mechanical coupling relationship dynamically links the tire-soil interaction force acting on the tires with the implement-soil interaction force acting on the traction frame through the movement and force balance of the tractor body, forming a closed-loop force transmission system.

[0081] In practice, this mechanical coupling relationship is achieved by establishing the Newton-Euler dynamics equations for the tractor body, with the equations in the following form: ; in, For the overall quality of the tractor, Let the position vector of the vehicle's center of mass be denoted as . Let ω be the angular velocity vector of the vehicle body. For tire-soil interaction force, For the interaction between machinery and soil, For the weight of the whole vehicle, To constrain the reaction force, Let the vehicle body inertia tensor be... and These are the torques generated on the vehicle body by the tire-soil interaction force and the implement-soil interaction force, respectively.

[0082] By solving this set of dynamic equations, the translational acceleration and rotational acceleration of the vehicle body can be obtained simultaneously, realizing the closed-loop transmission of force flow from the tires to the vehicle body and then to the machine.

[0083] The equation is solved numerically in the ADAMS software using the "Motion Solver" module with implicit integration, ensuring the stability and accuracy of the calculation for high-stiffness systems.

[0084] Through the above modeling and equation solving, the tire-soil interaction force and the implement-soil interaction force are dynamically linked in the tractor body, forming a complete mechanical coupling relationship.

[0085] S43: Based on the mechanical coupling relationship established in S42, the initial multibody dynamics model containing all external loads is verified to ensure the correctness and integrity of the kinematic pairs and constraint settings between components, the application of all external loads, and the force flow transmission path. Specifically: In the multibody dynamics simulation software ADAMS, the verification process is completed through model initialization and static equilibrium calculation.

[0086] First, perform model initialization to check the topological consistency of the connection relationships of components such as the vehicle body, tires, traction frame, drive shaft and engine, and ensure that there is no redundancy or conflict in the kinematic pair type, degree of freedom setting and constraint equation; Then, a static equilibrium calculation is performed to make the system reach a force equilibrium state under the combined action of gravity and external load, and to verify whether the balance accuracy of the tire ground reaction force and the traction force of the implement hook meets the set error threshold (error less than 1%).

[0087] If the reaction force distribution and load transfer path of the model in static equilibrium state are consistent with the expectations, it indicates that the system's constraints, force flow, and load coupling relationships are all set correctly.

[0088] Through the above verification process, a holistic coupled multibody dynamics model that accurately reflects the interaction between the tire, soil, and implement is finally generated. This model not only has complete structural constraints and force system, but also can accurately predict the tractor's overall traction performance, attitude changes, and power transmission characteristics in dynamic simulation, providing a highly reliable model foundation for solving the dynamic response in S5.

[0089] S5: Solve the overall coupled multibody dynamics model to obtain the dynamic response data of the transmission system, specifically: S51: Set the simulation solution parameters for the overall coupled multibody dynamics model generated by S4, specifically as follows:

[0090] In the multibody dynamics simulation software, the solver is initialized for the model, and the simulation time, integration step size, and numerical integration algorithm are set.

[0091] The simulation time is determined based on the actual operating conditions of the tractor, typically ranging from 3 to 10 seconds, to cover the acceleration, stable driving, and loading fluctuation phases. The integral step size is set to 0.001 to 0.005 seconds to ensure the accuracy of capturing the rapid dynamic response process.

[0092] Numerical integration algorithms employ the GSTIFF integrator, WSTIFF integrator, or Runge-Kutta method.

[0093] Among them, the GSTIFF integrator is based on the Gear rigid differential equation solving algorithm and is suitable for multibody dynamics models with high system stiffness; the WSTIFF integrator adopts an improved weighted implicit algorithm, which can effectively handle nonlinear constrained systems; the Runge-Kutta method is an explicit integration algorithm and is suitable for real-time calculation in medium and low stiffness systems.

[0094] In this invention, to balance computational efficiency and stability, the GSTIFF integrator is preferred for solving the problem.

[0095] Furthermore, to avoid computational divergence, error tolerance settings must be applied to the model before solving. The absolute error tolerance is set to... The relative error limit is set to It also enables automatic step size adjustment to ensure computational stability in the high-frequency vibration and nonlinear shock regions.

[0096] After completing the above settings, a global coupled multibody dynamics model to be solved is formed.

[0097] S52: Based on the solution parameters set in S51, the solver of the multibody dynamics simulation software is used to perform numerical integration calculations on the global coupled multibody dynamics model to be solved, obtaining the original response data of the system in the time domain, specifically: The multibody dynamics simulation software used is ADAMS.

[0098] During the calculation process, the software solver solves all kinematic pairs, constraint equations and external loads of the system simultaneously based on the Newton-Euler dynamic equations established by S4.

[0099] The simulation considers the dynamic feedback of engine output torque, transmission inertia inside the gearbox, torque transmitted by the drive shaft, and interaction forces between the tires and the soil and between the implement and the soil, so that the power transmission process can truly reflect the coupling characteristics of the vehicle's traction system.

[0100] During the calculation process, the system records the state variables of each component in real time, including displacement, velocity, acceleration and force changes, and outputs the state result once for each time step.

[0101] The raw response data is stored in time series format, including force, torque, speed, angular displacement and energy distribution at each key node, providing a complete data foundation for subsequent extraction of relevant parameters of the transmission system.

[0102] To ensure the accuracy and repeatability of the data, an energy conservation check is performed after the simulation to verify whether the deviation between the system input power and output power is less than 2%. If it exceeds the threshold, the integration step size is automatically adjusted and the calculation is recalculated to ensure numerical accuracy.

[0103] S53: Extract specific physical quantities related to the transmission system from the raw response data obtained in S52 to generate the dynamic response data of the transmission system, specifically: The simulation post-processing module performs signal filtering and feature extraction on the raw response data.

[0104] The specific physical quantities extracted include engine output torque, transmission shaft load, drive shaft speed, transmission gear meshing force, and tire slip ratio.

[0105] in: Engine output torque characterizes the engine's instantaneous output capability under different load conditions and is obtained through torque sensing calculation at the engine output shaft node; The gearbox shaft load reflects the stress condition of the gearbox input shaft and output shaft, and is calculated by superimposing the axial force and radial force at the bearing nodes; The drive shaft speed characterizes the angular velocity response at the output end of the transmission system, and the angular velocity change curve of the drive shaft node is calculated in real time. The gear meshing force of the gearbox is calculated through the tooth surface contact unit, representing the power transmission strength inside the transmission system; Tire slip ratio characterizes the adhesion and traction properties between the tire and the soil, and is calculated by the difference between the actual linear velocity and the theoretical linear velocity at the tire contact point.

[0106] After extraction, the data is filtered and smoothed to eliminate the influence of numerical integration error on the results.

[0107] The final output is a dynamic response data file of the transmission system, including time-torque curves, time-speed curves, time-slip rate curves, and time-gear meshing force curves.

[0108] S6: Based on the dynamic response data, analyze the tractor's traction efficiency and energy consumption indicators, specifically: S61: Based on the dynamic response data obtained in S5, extract the traction force of the implement hook acting on the tractor drawbar connection point and the actual travel speed of the tractor to calculate the traction power; simultaneously, extract the engine's output torque and speed to calculate the engine's output power, and then calculate the tractor's traction efficiency by using the ratio of traction power to engine output power. The steps are as follows: The traction force of the implement hook is directly extracted from the dynamic response data. With the actual speed of the tractor Calculate traction power : ; in, The traction force of the hook on the machine is expressed in Newtons (N). The actual speed of the tractor is expressed in meters per second (m / s). This refers to traction power, measured in watts (W).

[0109] At the same time, engine output torque is extracted from the dynamic response data. With rotational speed Calculate engine output power : ; in, Engine output torque, measured in Newton-meters (N:m); Engine speed, measured in radians per second (rad / s). Engine output power, measured in watts (W).

[0110] Tractor traction efficiency The calculation formula is: ; The calculation process uses the time step integration method to calculate the average value of the instantaneous efficiency at each moment, thus obtaining the average traction efficiency of the tractor over the entire working cycle.

[0111] The calculation results are output as a time-efficiency curve and an average efficiency value, reflecting the energy transfer efficiency of the transmission system under different load and speed conditions.

[0112] S62: Based on the traction efficiency calculated in S61 and the engine fuel consumption rate or motor input current extracted from the dynamic response data, combined with the total simulation time, the total energy consumption index of the tractor in completing a specific task is calculated, specifically: When the tractor is driven by a conventional internal combustion engine, the engine fuel consumption rate Fuel consumption is obtained as a key parameter from the dynamic response data. Calculated by time integration: ; in, For the total simulation time, the fuel consumption rate is... The unit is grams per second (g / s), and the integral result is... The unit is grams (g). Based on the calorific value of fuel oil. (Unit: MJ / kg) can be used to calculate the total energy consumption of a tractor. : ; When the tractor is an electric tractor, the motor input current Key parameters are obtained from the dynamic response data. This is combined with the system operating voltage. Calculate the motor input power ; ; The total energy consumption is obtained by integrating the time over the entire operation cycle. : ; Finally, the calculated total energy consumption index is correlated with the average traction efficiency to form a traction efficiency-energy consumption characteristic diagram, providing basic data for economic evaluation under different operating modes.

[0113] All energy consumption calculations are performed using a standardized unit system to ensure comparability between fuel-powered and electric tractors.

[0114] S63: Combining the traction efficiency calculated in S61 and the total energy consumption index calculated in S62, a quantitative comparative analysis of the traction performance and economy of the tractor's integral transmission system under different soil parameters and implement operating parameters is conducted, generating a traction efficiency and energy consumption index analysis report. The steps are as follows: Based on different simulation conditions, soil parameters and machinery operation parameters are configured in combination. These different soil parameters and machinery operation parameters specifically include soil hardness, soil type, machinery weight, and machinery tillage depth.

[0115] By changing the above parameters one by one, batch simulation calculations are performed to obtain the corresponding traction efficiency and energy consumption index datasets.

[0116] During the analysis phase, two-dimensional and three-dimensional data visualization methods were used to draw the traction efficiency-soil hardness relationship curve, the energy consumption index-machine weight scatter distribution map, and the traction efficiency-energy consumption index joint contour map.

[0117] By using data fitting and regression analysis, the pattern of traction efficiency variation with soil and equipment parameters was identified, and the optimal working range was determined.

[0118] The final output is a traction efficiency and energy consumption index analysis report, which includes the following: (1) Data table of traction efficiency and energy consumption under various simulation conditions; (2) Trend chart of traction efficiency and energy consumption indicators; (3) System performance comprehensive evaluation index and optimization suggestions.

[0119] This analysis report provides quantitative basis for the design optimization of tractor integrated transmission systems. It can be used to evaluate the comprehensive impact of different soil conditions and implement parameters on traction performance and economy, and has application value in guiding the optimization of actual agricultural machinery power systems and the selection of operating parameters.

[0120] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0121] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multibody dynamics coupling modeling method for a tractor's integrated transmission system that relates tire-soil-implementation interaction, characterized in that, Includes the following steps: S1: Construct an initial multibody dynamics model of the tractor's integrated transmission system. The initial multibody dynamics model includes the geometric and inertial parameters of the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires. S2: Based on the initial multibody dynamics model, a tire-soil interaction model is introduced, and the tire-soil interaction force is calculated using soil hardness parameters and tire pressure parameters. S3: Based on the tire-soil interaction force calculated in S2, a machine-soil interaction model is introduced, and the machine-soil interaction force is calculated using machine weight parameters and soil type parameters; S4: Integrate the tire-soil interaction force and the implement-soil interaction force into the initial multibody dynamics model to generate an overall coupled multibody dynamics model; S5: Solve the overall coupled multibody dynamics model to obtain the dynamic response data of the transmission system; S6: Based on the dynamic response data, analyze the tractor's traction efficiency and energy consumption indicators.

2. The multibody dynamics coupling modeling method for a tractor integrated transmission system with associated tire-soil-implement interaction as described in claim 1, characterized in that, S1 includes: S11: Based on the tractor's design drawings and 3D model, obtain the geometric parameters of the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires. The geometric parameters include the external dimensions, mass attributes, spatial installation position, and connection relationship of each component in the whole vehicle, thereby establishing the geometric parameters of the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires. S12: Based on the geometric parameters of the engine, main and auxiliary transmissions, transfer case, front drive axle, rear drive axle, and tires established in S11, the inertial parameters of the engine, main and auxiliary transmissions, transfer case, front drive axle, rear drive axle, and tires are determined by calculation or experimental measurement. The inertial parameters include the mass, center of mass position, and moment of inertia about each component. S13: The geometric parameters of the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires obtained in S11, as well as the inertial parameters of the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires obtained in S12, are imported into the multibody dynamics simulation software as component attributes. Based on the spatial installation position and connection relationship of each component, corresponding kinematic pairs and constraints are added. Finally, a multibody dynamics initial model of the tractor's integrated transmission system, including the engine, main and auxiliary gearboxes, transfer case, front drive axle, rear drive axle, and tires, is constructed.

3. The multibody dynamics coupling modeling method for a tractor integrated transmission system with associated tire-soil-implement interaction as described in claim 2, characterized in that, In step S12, the inertial parameters of the engine, gearbox, drive shaft, and tires are determined by calculation or experimental measurement. Specifically, the inertial parameters of each component are automatically calculated and output based on the geometric parameters of the engine, gearbox, drive shaft, and tires established in step S11 using the mass attribute analysis function of the 3D modeling software.

4. The multibody dynamics coupling modeling method for a tractor integrated transmission system with associated tire-soil-implement interaction as described in claim 2, characterized in that, S2 includes: S21: Based on the geometric parameters and spatial pose of the tire in the initial model of the multibody dynamics, determine the geometric characteristics of the contact area between the tire and the soil, and obtain the soil hardness parameters obtained by field measurement or soil database query, as well as the tire pressure parameters determined by tire pressure sensor measurement or design specifications. S22: Based on the soil hardness and tire pressure parameters determined in S21, select and call the tire-soil interaction model constructed based on the Bekker pressure-settlement relationship and the Janosi shear stress-displacement relationship. S23: The soil hardness parameters and tire pressure parameters obtained in S21, as well as the geometric parameters and motion state of the tire in the initial multibody dynamics model, are used as input variables and substituted into the tire-soil interaction model called in S22 to calculate the normal pressure distribution and tangential shear stress distribution acting on the tire ground surface. S24: Integrate the normal pressure distribution and tangential shear stress distribution on the tire ground surface obtained from S23 within the contact area defined by the tire-soil interaction model to obtain the total tire-soil interaction force acting on the tire. This total tire-soil interaction force includes the vertical support force, longitudinal traction force and lateral force in three-dimensional space. S25: The total tire-soil interaction force calculated in S24 is used as an external load and applied to the corresponding tire component in the initial multibody dynamics model to complete the mechanical coupling between the tire-soil interaction model and the initial multibody dynamics model.

5. The multibody dynamics coupling modeling method for a tractor integrated transmission system with associated tire-soil-implement interaction as described in claim 4, characterized in that, In step S21, the soil hardness parameters include soil cohesion, soil internal friction angle, and soil deformation modulus.

6. The multibody dynamics coupling modeling method for a tractor integrated transmission system with associated tire-soil-implement interaction as described in claim 4, characterized in that, S3 includes: S31: Based on the tire-soil interaction force calculated by S2, combined with the position of the tractor's drawbar connection point, the traction force of the implement hook acting on the drawbar connection point is calculated through static equilibrium relationship, and the implement weight parameters obtained by design manual or direct weighing and the soil type parameters obtained by on-site identification or soil database query are obtained. S32: Based on the soil type parameters obtained in S31, select and call the implement-soil interaction model applicable to the soil type parameters. The implement-soil interaction model is a mathematical model based on classical soil mechanics theory for predicting the working resistance of the working parts of the implement under specific soil type parameters. S33: Take the implement weight parameters obtained in S31 and the implement hook traction force calculated in S31 as key input variables, substitute them into the implement-soil interaction model called in S32, and calculate the total working resistance of the implement working parts during the tillage process, that is, the implement-soil interaction force. S34: The implement-soil interaction force calculated in S33 is applied as an external load to the tractor's traction frame connection point in the multibody dynamics initial model in the form of a reaction force, thereby completing the mechanical coupling between the implement-soil interaction model and the multibody dynamics initial model.

7. The multibody dynamics coupling modeling method for a tractor integrated transmission system with associated tire-soil-implement interaction as described in claim 6, characterized in that, The soil type parameters in S31 include soil bulk density, soil moisture content, and soil firmness.

8. The multibody dynamics coupling modeling method for a tractor integrated transmission system with associated tire-soil-implement interaction as described in claim 6, characterized in that, S4 includes: S41: Confirm that the tire-soil interaction force calculated by S2 has been applied as an external load to the tire component of the multibody dynamics initial model, and at the same time confirm that the implement-soil interaction force calculated by S3 has been applied as an external load to the traction frame connection point of the multibody dynamics initial model, thereby completing the application of all external loads and forming a multibody dynamics initial model containing all external loads. S42: Based on the multibody dynamics initial model containing all external loads formed in S41, establish the mechanical coupling relationship between the tire-soil interaction force and the implement-soil interaction force. This mechanical coupling relationship dynamically links the tire-soil interaction force acting on the tire and the implement-soil interaction force acting on the traction frame through the motion and force balance of the tractor body, forming a closed-loop force transmission system. S43: Based on the mechanical coupling relationship established in S42, verify the correctness and completeness of the kinematic pairs and constraints between the components, the application of all external loads, and the force flow transmission path in the initial multibody dynamics model containing all external loads. Finally, generate an overall coupled multibody dynamics model that can accurately reflect the interaction between tire, soil, and machinery.

9. The multibody dynamics coupling modeling method for a tractor integrated transmission system with associated tire-soil-implement interaction as described in claim 8, characterized in that, S5 includes: S51: Set the solution parameters for the overall coupled multibody dynamics model generated in S4, including simulation time, integration step size and numerical integration algorithm, to form the overall coupled multibody dynamics model to be solved; S52: Based on the solution parameters set in S51, the solver of the multibody dynamics simulation software is used to perform numerical integration calculations on the overall coupled multibody dynamics model to be solved, and the original response data of the system in the time domain is obtained. S53: Extract specific physical quantities related to the transmission system from the raw response data obtained in S52, including engine output torque, gearbox shaft load and drive shaft speed, to generate the dynamic response data of the transmission system.

10. A multibody dynamics coupling modeling method for a tractor integrated transmission system with associated tire-soil-implement interaction as described in claim 9, characterized in that, S6 includes: S61: Based on the dynamic response data obtained in S5, extract the traction force of the implement hook acting on the tractor drawbar connection point and the actual driving speed of the tractor, calculate the traction power, extract the engine output torque and speed, calculate the engine output power, and then calculate the tractor traction efficiency by the ratio of traction power to engine output power. S62: Based on the traction efficiency calculated in S61 and the engine fuel consumption rate or motor input current extracted from the dynamic response data, combined with the total simulation time, the total energy consumption index of the tractor in the process of completing a specific task is calculated. S63: Combining the traction efficiency calculated in S61 and the total energy consumption index calculated in S62, a quantitative comparative analysis of the traction performance and economy of the tractor's integral transmission system under different soil parameters and implement operating parameters is conducted, generating a traction efficiency and energy consumption index analysis report for evaluating and optimizing system design.

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