Tractor gearbox dynamic load simulation model and construction method thereof

Abstract

The invention relates to a tractor gearbox dynamic load simulation model and a construction method thereof, a multi-working-condition dynamic load model is constructed according to the complex terrain and working conditions of agricultural machinery by considering the coupling relationship among the working conditions, meanwhile, working condition driving is subjected to parameterization design, and a working condition type + parameter input model is constructed; an effective mapping relation is established between working condition types and load output, multi-working-condition switching logic is further provided, various typical farmland operation working conditions can be simulated in a high-fidelity mode, load change characteristics can be dynamically reflected, loads can be output to a mechanical transmission model, and when the system is applied to a tractor hardware-in-loop test, the reliability of the system is improved. The test coverage rate and the control strategy verification capability of the tractor controller can be greatly improved, potential problems of the control strategy under extreme or special working conditions can be found in time, and the product reliability and adaptability are improved.

Description

Technical Field

[0001] This invention relates to the field of tractor gearbox simulation technology, specifically to a dynamic load simulation model for a tractor gearbox and its construction method. Background Technology

[0002] As global agricultural production shifts towards precision and efficiency, the operating environment of tractors is becoming increasingly complex. To adapt to rapidly changing market demands, tractor controllers require hardware-in-the-loop (HIL) testing before actual installation on vehicles. This shortens product development cycles and maximizes the reliability of the final product. A core aspect of HIL simulation testing is the construction of a gearbox simulation model.

[0003] Existing transmission simulation models are mostly used for passenger vehicles. The load models built in these models usually adopt constant load or simple dynamic models, which cannot reflect the real complex environment. However, for agricultural machinery, the working environment is complex and variable. Existing simulation models lack a flexible, parameterized, and real-time adjustable load simulation method, resulting in insufficient verification of transmission control strategies (such as shift logic and torque regulation) under complex working conditions.

[0004] A search revealed that some existing studies on tractor gearbox simulation models still use a single, constant load model, making it difficult to verify the response capability of the control strategy in a dynamic environment. Other simulation models, while considering load changes under complex tractor operating conditions, only mention dynamic load conceptually, lacking specific modeling methods, implementation steps, and multi-condition switching logic, and thus failing to achieve true dynamic load simulation.

[0005] There is an urgent need for a method to construct a dynamic load simulation model for tractor gearboxes, which can be used for high-fidelity, dynamic, and complex multi-condition simulations to verify the response capability and robustness of control strategies in dynamic environments. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a dynamic load simulation model for tractor gearboxes and its construction method, which can simulate various typical farmland operation conditions with high fidelity, dynamically reflect load change characteristics, and improve the verification accuracy and coverage of gearbox control strategies.

[0007] To achieve the above objectives, the technical solution adopted by this invention is: a dynamic load simulation model for a tractor gearbox, comprising: a control input interface, a mechanical transmission model, a sensor simulation module, a total load model, an NI real-time simulation platform, and a TCU controller; the total load model includes: a working condition type + parameter input model and a dynamic load model, the dynamic load model including a soil resistance load model, a slope resistance load model, and a traction implement load model; the total load model is connected to the mechanical transmission model and is used to activate the corresponding load model in the dynamic load model according to the input of the working condition type + parameter input model, and output the load to the mechanical transmission model; the TCU controller is connected to the NI real-time simulation platform and sends control signals; the NI real-time simulation platform is connected to the mechanical transmission model through the control input interface; the mechanical transmission model realizes load changes according to the load output by the total load model; the mechanical transmission model is also connected to the sensor simulation model; the sensor simulation model is connected to the NI real-time simulation platform; the NI real-time simulation platform outputs sensor signals to the TCU controller to realize closed-loop control.

[0008] Furthermore, the input of the working condition type + parameter input model includes working condition type and working condition parameters. The working condition type includes: soil type, slope type, agricultural implement type and initial working condition; the working condition parameters include: tillage depth, speed, slope, soil density, vehicle mass and tire radius.

[0009] Furthermore, the soil types include: sandy soil and clay soil; the slope types include: uphill and downhill; the agricultural implement types include: plow, harrow, and rotary tiller; the initial working conditions are a combination of sandy soil, flat road, and no agricultural implement conditions.

[0010] Furthermore, the mechanical transmission model is the gearbox body.

[0011] This invention also provides a method for constructing a dynamic load simulation model of a tractor gearbox, comprising the following steps: The design working condition type + parameter input model includes working condition type and working condition parameters. The working condition type includes: soil type, slope type, agricultural implement type and initial working condition; the working condition parameters include: tillage depth, speed, slope, soil density, vehicle mass and tire radius. Design dynamic load models, including soil resistance load models, slope resistance load models, and traction implement load models. Create a load database from the inputs and outputs of all dynamic load models. Based on the dynamic working condition switching logic, and on the existing load database, the corresponding dynamic load model is activated according to the working condition type and parameter input model. The corresponding load is obtained by looking up the table in the load model database. The load output from the dynamic load model is input to the output shaft of the mechanical transmission model to achieve load change.

[0012] Furthermore, the soil resistance load model calculates the dynamic soil resistance torque based on driving speed, tillage depth, soil type, and ground conditions. The modeling formula is: T soil =f(v,θ,h,p,soil-type), where T soil denoted as dynamic soil resistance torque, v as driving speed, θ as slope, h as tillage depth, p as soil density, and soil-type as soil type.

[0013] Furthermore, the ramp resistance load model generates additional ramp resistance in real time based on the current simulated ramp angle and vehicle mass, increasing the equivalent ramp resistance torque when going uphill. The modeling formula is: T slope =m*g*sin(α)*r, where T slope The additional resistance torque for the ramp is given by α, where α is the slope angle, m is the vehicle mass, and r is the tire radius.

[0014] Furthermore, the traction implement load model simulates different traction load characteristics based on the type of attached implement and its operating parameters.

[0015] Furthermore, the specific process of activating the corresponding dynamic load model based on the input of the working condition type and parameters is as follows: If the input is soil type, the soil resistance load model is activated, and the corresponding output torque is obtained by looking up the table based on the working condition input parameters and output to the mechanical transmission model; if the input is slope type, the slope resistance load model is activated, and the corresponding output torque is obtained by looking up the table based on the working condition input parameters and output to the mechanical transmission model; if the input is operation type, the traction implement resistance model is activated, and the corresponding output torque is obtained by looking up the table based on the working condition input parameters and output to the mechanical transmission model.

[0016] Furthermore, if the input is any two or more working conditions among soil type, slope type, and operation type, the corresponding resistance model is activated respectively, the corresponding torque is obtained, and the torque obtained by directly superimposing them is output to the mechanical transmission model.

[0017] The present invention achieves the following positive effects by adopting the above technical solution: 1. The dynamic load simulation model constructed in this invention considers the load characteristics under complex working conditions, establishes a dynamic load model with multiple working conditions, and parametrically designs the working condition drive, constructing a working condition type + parameter input model. The modeling of each load considers the coupling relationship between each working condition. Through the effective mapping between the input of working condition type + parameters and the output of the load model, a multi-working condition switching logic is proposed, which can perform complex, dynamic, and variable load simulation and output. It can simulate a variety of typical farmland operation conditions with high fidelity and dynamically reflect the load change characteristics (such as soil resistance, slope, traction force changes, etc.). When applied to the gearbox transmission model, it can make the model simulation accurate and more realistically reflect the force and response characteristics of the gearbox in actual operation.

[0018] 2. The dynamic load simulation model of the tractor gearbox of the present invention, when applied to the hardware-in-the-loop simulation of the tractor controller, can support complex, dynamic and varied working condition simulation, greatly improve the test coverage and control strategy verification capability of the tractor controller, promptly discover potential problems of the control strategy under extreme or special working conditions, and improve product reliability and adaptability.

[0019] 3. This invention incorporates operating condition types and parameter inputs, as well as dynamic switching logic for multiple operating conditions into the dynamic load model, enabling it to use a parameterized and modular design. This facilitates future expansion and reuse, and can adapt to different types of gearboxes and agronomic needs.

[0020] In summary, the dynamic load simulation model of the tractor gearbox and its construction method of the present invention can realize high-fidelity, dynamic, and complex multi-condition simulation to verify the response capability and robustness of the control strategy in a dynamic environment, and eliminate the problem of insufficient verification caused by the load model in the hardware-in-the-loop test and development process of the tractor vehicle controller. Attached Figure Description

[0021] Figure 1 This is an overall architecture diagram of the dynamic load simulation model for the tractor gearbox of the present invention.

[0022] Figure 2 This is a structural diagram of the total load model of the present invention.

[0023] Figure 3 This is a flowchart illustrating the implementation of the dynamic operating condition switching logic of the present invention. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1As shown, a dynamic load simulation model of a tractor gearbox is presented. The overall architecture includes: a control input interface, a mechanical transmission model (gearbox body), a sensor simulation module, a total load model, an NI real-time simulation platform, and a TCU controller. The total load model includes a working condition type + parameter input model and a dynamic load model. The dynamic load model includes: soil resistance load model, slope resistance load model, and traction implement load model. The TCU controller is interconnected with the NI real-time simulation platform. The NI real-time simulation platform is connected to the mechanical transmission model through a control input interface. The total load model is connected to the mechanical transmission model to provide load input. The output of the mechanical transmission model is connected to the sensor simulation module, which is connected to the NI real-time simulation platform. The TCU controller inputs control signals such as speed change requests to the NI real-time simulation platform. The NI real-time simulation platform then transmits these control signals to the mechanical transmission model through the control input interface for gear shifting and other controls. The total load model activates the corresponding dynamic load model output based on the input working condition type + parameters, which serves as the input to the mechanical transmission model, generating traction force under different working conditions. This drives the mechanical transmission model to respond according to the load conditions. The mechanical transmission model outputs signals such as rotational speed to the NI real-time simulation platform through the sensor simulation module. The NI real-time simulation platform then transmits these sensor signals to the TCU controller, achieving closed-loop control.

[0026] like Figure 2 As shown, the overall load model includes: a working condition type + parameter input model and a dynamic load model. The working condition type + parameter input model includes working condition types and parameters. Working condition types include: soil type, slope type, implement type, and initial working condition. Soil types include: sandy soil and clay. Slope types include: uphill and downhill. Implement types include: plow, harrow, and rotary tiller. Working condition parameters include: tillage depth, speed, slope, soil density, vehicle weight, and tire radius. The initial working condition is a combination of sandy soil, flat road, and no implement working conditions. The dynamic load model includes: a soil resistance load model, a slope resistance load model, and a traction implement load model. The working condition type output of the working condition type + parameter input model activates the corresponding resistance load model output in the dynamic load model to output the load.

[0027] A method for constructing a dynamic load simulation model for a tractor gearbox is as follows: (1) Design working condition type + parameter input model; (2) Design a dynamic load model; (3) Activate the corresponding dynamic load model by inputting the working condition type parameters into the model output; (4) Input the load output by the total load model to the output shaft of the mechanical transmission model to realize load change.

[0028] The dynamic load model consists of three models: a soil resistance load model, a slope load model, and a traction implement load model. In constructing the dynamic load model, the soil resistance load model calculates the dynamic soil resistance torque based on driving speed, tillage depth, soil type, and ground conditions. The modeling formula is: T soil =f(v,θ,h,p,soil-type), where T soil The dynamic soil resistance torque is given by: v = driving speed, θ = slope, h = tillage depth, p = soil density, and soil-type = soil type (clay / sand, etc.). The slope resistance load model generates additional slope resistance in real time based on the current simulated slope angle and vehicle mass, adding an equivalent slope resistance torque when going uphill. The modeling formula is: T slope =m*g*sin(α)*r, where T slope The slope is given an additional resistance torque, where α is the slope angle, m is the total vehicle mass, g is the gravitational acceleration, and r is the tire radius. The traction implement load model simulates different traction load characteristics based on the type of attached implement and its operating parameters (plowing depth, operating speed, etc.). The loads of all the above dynamic load models have been compiled into a load database based on the input and output, which will not be described in detail in this invention.

[0029] The output of the total load model is determined by the input of the working condition type + parameter input model. The working condition type includes: soil type, slope type, implement type, and initial working condition; the working condition parameters include: tillage depth, speed, slope, soil density, vehicle mass, and tire radius. The initial working condition is a combination of sandy soil, flat road, and no implement working conditions.

[0030] This invention also provides dynamic load switching logic for complex operating conditions when constructing a dynamic load simulation model, such as... Figure 3As shown, the implementation process is as follows: input the working condition type and parameters, select and activate the corresponding resistance load model, look up the corresponding load through the load model database, output the corresponding load, and finally input the load output by the total load model to the output shaft of the mechanical transmission model to realize the load change. The specific process is as follows: Based on the existing load database, according to the input working condition type and parameters, if the input is soil type, such as clay, the soil resistance load model is activated. Based on the working condition input parameters (tillage depth, speed), the corresponding output torque is obtained from a table and output to the mechanical transmission model. If the input is slope condition, such as uphill, the slope resistance load model is activated. Based on the working condition input parameters (slope angle), the corresponding output torque is obtained from a table and output to the mechanical transmission model. If the input is operation type, such as plowing, the traction implement resistance model is activated. Based on the working condition input parameters (tillage depth, speed), the corresponding output torque is obtained from a table and output to the mechanical transmission model. The above are the cases for a single working condition. If the input includes any two or more working conditions such as soil type, slope condition, and operation type, the corresponding resistance models are activated respectively to obtain the corresponding torque, and the torque obtained by directly superimposing these values ​​is output to the mechanical transmission model.

[0031] The TCU controller outputs control signals to the NI real-time simulation platform 8. The NI real-time simulation platform sends these signals to the mechanical transmission model through the control input interface. The mechanical transmission model outputs signals from each sensor to the sensor simulation module based on the total load input. The sensor simulation module then outputs these signals back to the NI real-time simulation platform, which in turn outputs them back to the TCU controller, thus achieving closed-loop control.

[0032] Using the above-mentioned method for constructing a dynamic load simulation model for tractor gearboxes, this simulation model can reproduce the load change characteristics of tractors under complex working conditions with high fidelity. The load signal is then input to the gearbox model to verify the response capability and robustness of the control strategy in a dynamic environment, thus eliminating the problem of insufficient verification caused by the load model during the hardware-in-the-loop test and development of the tractor vehicle controller.

[0033] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will still be able to make non-substantially different modifications to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. Therefore, any modifications, equivalent substitutions, or non-substantially improved features made within the scope of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dynamic load simulation model for a tractor gearbox, characterized in that, include: Control input interface, mechanical transmission model, sensor simulation module, total load model, NI real-time simulation platform and TCU controller; The total load model includes: a working condition type + parameter input model and a dynamic load model. The dynamic load model includes a soil resistance load model, a slope resistance load model, and a traction implement load model. The total load model is connected to the mechanical transmission model and is used to activate the corresponding load model in the dynamic load model based on the input of the working condition type + parameter input model, and output the load to the mechanical transmission model. The TCU controller is connected to the NI real-time simulation platform and sends control signals. The NI real-time simulation platform is connected to the mechanical transmission model through a control input interface. The mechanical transmission model realizes load changes based on the load output by the total load model. The mechanical transmission model is also connected to a sensor simulation model, which is connected to the NI real-time simulation platform. The NI real-time simulation platform outputs sensor signals to the TCU controller to achieve closed-loop control.

2. The dynamic load simulation model for a tractor gearbox according to claim 1, characterized in that, The input of the working condition type + parameter input model includes working condition type and working condition parameters. The working condition type includes: soil type, slope type, agricultural implement type and initial working condition; the working condition parameters include: tillage depth, speed, slope, soil density, vehicle mass and tire radius.

3. The dynamic load simulation model for a tractor gearbox according to claim 2, characterized in that, Soil types include: sandy soil and clay; slope types include: uphill and downhill; agricultural implement types include: plow, harrow, and rotary tiller; the initial working conditions are a combination of sandy soil, flat road, and no agricultural implement conditions.

4. The dynamic load simulation model for a tractor gearbox according to claim 1, characterized in that, The mechanical transmission model is the gearbox body.

5. A method for constructing a dynamic load simulation model of a tractor gearbox according to any one of claims 1-4, characterized in that, Includes the following steps: The design working condition type + parameter input model includes working condition type and working condition parameters. The working condition type includes: soil type, slope type, farm implement type and initial working condition. Operating parameters include: tillage depth, speed, slope, soil density, vehicle weight, and tire radius; Design dynamic load models, including soil resistance load models, slope resistance load models, and traction implement load models. Create a load database from the inputs and outputs of all dynamic load models. Based on the dynamic working condition switching logic, and on the existing load database, the corresponding dynamic load model is activated according to the working condition type and parameter input model. The corresponding load is obtained by looking up the table in the load model database. The load output from the dynamic load model is input to the output shaft of the mechanical transmission model to achieve load change.

6. The method for constructing a dynamic load simulation model of a tractor gearbox according to claim 5, characterized in that: The soil resistance load model calculates the dynamic soil resistance moment based on driving speed, tillage depth, soil type, and ground conditions. The modeling formula is: T soil =f(v,θ,h,p,soil-type), where T soil denoted as dynamic soil resistance torque, v as driving speed, θ as slope, h as tillage depth, p as soil density, and soil-type as soil type.

7. The method for constructing a dynamic load simulation model of a tractor gearbox according to claim 5, characterized in that: The ramp resistance load model generates additional ramp resistance in real time based on the current simulated ramp angle and vehicle mass, adding an equivalent ramp resistance torque when going uphill. The modeling formula is: T slope =m*g*sin(α)*r, where T slope The additional resistance torque for the ramp is given by α, where α is the slope angle, m is the vehicle mass, and r is the tire radius.

8. The method for constructing a dynamic load simulation model of a tractor gearbox according to claim 5, characterized in that: The traction implement load model simulates different traction load characteristics based on the type of attached implement and its operating parameters.

9. The method for constructing a dynamic load simulation model of a tractor gearbox according to claim 5, characterized in that: The specific process of activating the corresponding dynamic load model based on the input of the working condition type and parameters is as follows: If the input is soil type, the soil resistance load model is activated, and the corresponding output torque is obtained by looking up the table based on the working condition input parameters and output to the mechanical transmission model; if the input is slope type, the slope resistance load model is activated, and the corresponding output torque is obtained by looking up the table based on the working condition input parameters and output to the mechanical transmission model; if the input is operation type, the traction implement resistance model is activated, and the corresponding output torque is obtained by looking up the table based on the working condition input parameters and output to the mechanical transmission model.

10. The method for constructing a dynamic load simulation model of a tractor gearbox according to claim 9, characterized in that: If the input consists of any two or more working conditions from soil type, slope type, and operation type, the corresponding resistance model is activated to obtain the corresponding torque, and the torque obtained by directly superimposing these values ​​is output to the mechanical transmission model.

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