Paddy field light chassis variable steering damping physical simulation system and method based on steering tie rod projection

Abstract

The invention relates to the technical field of agricultural equipment, in particular to a paddy field light chassis variable steering damping physical simulation system and method based on steering tie rod projection, and the system comprises an input collection module which is used for obtaining a steering instruction signal inputted externally; the physical simulation module comprises a physical steering link mechanism used for reproducing the mechanical motion of an entity steering system; the variable load simulation device is connected with the physical steering link mechanism and is used for applying a simulation load according to the steering command signal so as to reproduce external resistance borne by the steering system under a preset working condition; the state sensing module is used for measuring motion state parameters of the physical steering link mechanism in real time; and the processing control module comprises a built-in kinematics model, and the kinematics model is established through a dimension reduction projection method based on three-dimensional geometric parameters and used for representing the mapping relation between the motion of the physical steering linkage mechanism in the three-dimensional space and the two-dimensional plane projection.

Description

Technical Field

[0001] This invention relates to the field of agricultural equipment technology, and in particular to a physical simulation system and method for variable steering damping of a light paddy field chassis based on the projection of the steering tie rod. Background Technology

[0002] As the platform supporting agricultural machinery such as rice transplanters and seeders, the handling and steering performance of light-duty power chassis in paddy field environments directly affects operational efficiency, crop quality, and energy consumption. Paddy field soil typically exhibits a complex layered structure, including a water layer, mud layer, topsoil layer, and subsoil. The soil characteristics are highly nonlinear, heterogeneous, and time-varying, resulting in significant and dynamically changing resistance on the steering wheels of the power chassis during steering. Currently, the industry primarily employs a development process combining 3D software simulation with real-vehicle testing for the design and optimization of steering systems for light-duty power chassis in paddy fields.

[0003] With the rapid development of computer-aided design and multibody dynamics simulation software (such as CATIA, SolidWorks, and ADAMS), 3D software simulation has become a preliminary tool for steering system design, enabling the rapid creation of geometric models and simulation of basic kinematic characteristics. However, existing 3D software simulation methods have significant drawbacks:

[0004] First, it is difficult to accurately simulate the complex mechanical properties of paddy field soil, such as the nonlinear changes, gradual and instantaneous processes of soil resistance (such as the transition from muddy to hard), which leads to a large deviation between the simulation model and the actual working conditions. Secondly, software models often simplify or ignore key parameters (such as the influence of caster angle and camber angle on the steering linkage system), resulting in simulation results lacking high fidelity and failing to effectively guide parameter optimization (such as the length of the steering tie rod).

[0005] The reason for these shortcomings is that soil mechanics modeling involves multi-physics coupling (including fluid mechanics and soil mechanics), and existing software algorithms and databases cannot handle these complex boundary conditions and uncertainties in real time and accurately.

[0006] After software simulation, R&D personnel typically move to the real-vehicle testing phase to verify the design and optimize parameters. While real-vehicle testing provides realistic performance data, it is inefficient, costly, and difficult to control under specific conditions. Specific drawbacks include: first, iterative parameter optimization is time-consuming; each adjustment of key geometric parameters (such as the length of the steering tie rod) requires remanufacturing a prototype, increasing labor and material costs; second, the repeatability of soil conditions is poor; real paddy field environments are affected by factors such as region, season, and water content, making it impossible to accurately reproduce consistent test conditions, especially for scenarios with gradually or rapidly changing soil resistance; and third, the testing scope is limited, as it cannot simulate various soil types in a laboratory environment, leading to inefficient data collection and analysis. The main reason for these problems is that real-vehicle testing relies on the external environment, making it impossible to achieve controllable load simulation and parameter adjustment, thus limiting its application in the early design phase.

[0007] In summary, existing technologies exhibit a disconnect between software simulation and real-vehicle testing: the former suffers from low reliability due to model distortion and insufficient soil simulation, while the latter is unsuitable for large-scale parameter optimization due to high cost, low efficiency, and uncontrollable conditions. Considering the current state of technology, such as the reliance on experience in steering system development in agricultural machinery and the lack of high-fidelity laboratory simulation in soil simulation technology, there is an urgent need in this field for a novel semi-physical simulation system capable of high-fidelity parameter optimization in a laboratory environment, flexibly simulating different soil conditions, and bridging the gap between software simulation and real-vehicle testing. This would reduce development costs, shorten the cycle time, and improve design quality. Summary of the Invention

[0008] The purpose of this invention is to design a physical simulation system and method for variable steering damping of a paddy field lightweight chassis based on the projection of the steering tie rod, thereby solving the aforementioned technical defects.

[0009] This invention provides a physical simulation system for variable steering damping of a paddy field lightweight chassis based on the projection of the steering tie rod, comprising: The input acquisition module is used to acquire steering command signals from external inputs; The physics simulation module includes: Physical steering linkage mechanism is used to replicate the mechanical motion of a physical steering system; A variable load simulation device, connected to the physical steering linkage mechanism, is used to apply a simulated load according to the steering command signal in order to reproduce the external resistance experienced by the steering system under preset operating conditions. The state sensing module is used to measure the motion state parameters of the physical steering linkage mechanism in real time. The processing control module includes: The built-in kinematic model is established based on three-dimensional geometric parameters through a dimensionality reduction projection method to characterize the mapping relationship between the motion of the physical steering linkage mechanism in three-dimensional space and the two-dimensional plane projection.

[0010] In the above scheme, the input acquisition module is responsible for acquiring external input steering command signals, such as the torque signal applied by the driver through the steering wheel; it is equivalent to a signal interface, and uses sensors (such as steering torque sensors) to achieve digital acquisition, ensuring the accuracy and real-time performance of the input signal.

[0011] The physical steering linkage mechanism is used to replicate the mechanical motion of a physical steering system, simulating the steering trapezoidal structure of a paddy field lightweight chassis (such as steering knuckle arms, steering tie rods, and steering butterfly). As a rigid mechanical component, it achieves kinematic simulation through hinged connections.

[0012] The variable load simulation device is mechanically connected to the physical steering linkage mechanism and is used to apply a variable simulated load according to control signals to reproduce the external resistance of the steering system under preset working conditions (such as paddy field soil resistance). This device is typically based on an adjustable damper to achieve gradual and transient simulation of soil resistance.

[0013] The state sensing module is responsible for measuring the motion state parameters of the physical steering linkage mechanism in real time, such as steering angle and torque. It uses sensors (such as angle sensors) to collect data and provide feedback signals, ensuring the system can monitor the deviation between actual output and theoretical calculations.

[0014] The processing and control module is the core control unit of the system, including a built-in kinematic model. The kinematic model is established based on three-dimensional geometric parameters (such as caster angle β and inclination angle α) using a dimensionality reduction projection method. It is used to characterize the mapping relationship between the motion of the physical steering linkage mechanism in three-dimensional space and its projection onto a two-dimensional plane. This module processes input signals, runs the calculation model, generates control commands, and manages communication with other modules.

[0015] Preferably, the variable load simulation device is a programmable steering damper, used to simulate in real time the nonlinear and time-varying steering resistance experienced by the steering system under different soil conditions or mixed conditions by adjusting its damping coefficient.

[0016] Preferably, the physical steering linkage mechanism includes a steering knuckle arm, a steering tie rod, and a steering butterfly; the steering butterfly is used to connect the input acquisition module to the steering tie rod, and the steering tie rod is used to transmit motion and force to the steering knuckle arm to drive the steering knuckle arm to deflect.

[0017] Preferably, the state sensing module includes a steering knuckle arm rotation angle sensor disposed on the steering knuckle arm rotation axis, used to measure the rotation angle of the steering knuckle arm in real time, and use the angle as a motion state parameter characterizing the actual output of the steering system.

[0018] Preferably, the processing control module is an in-vehicle embedded microcontroller; The vehicle-mounted embedded microcontroller is used to acquire sensor data in real time, run the kinematic model, and interact with the physical simulation module.

[0019] On the other hand, a physical simulation method for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection is applied to a physical simulation system for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection, including: S1: The kinematic model maps the three-dimensional spatial geometry of the steering system to a low-dimensional computational plane, and dynamically calculates the projection geometric parameters of each link of the steering system on the computational plane according to the preset three-dimensional spatial parameters; S2: Receive steering input command, and use the kinematic model to calculate the theoretical steering output value based on the steering input command and several geometric parameters of the steering system to be optimized; S3: Drive the physical simulation module, which applies a resistance load simulating external working conditions to the physical steering linkage mechanism through a variable load simulation device; S4: The actual steering output value of the physical steering linkage mechanism under the resistance load is measured in real time by the state sensing module, and the actual steering output value is compared with the preset ideal steering performance index to generate a performance deviation; S5: Based on the performance deviation, adjust the geometric parameters of the steering system to be optimized, and repeat steps S2 to S4 until the performance deviation meets the preset conditions.

[0020] Preferably, in step S1, the preset three-dimensional spatial parameters include at least the caster angle (β) and camber angle (α) of the steering kingpin. The process by which the kinematic model maps the three-dimensional spatial geometry of the steering system to the low-dimensional computational plane includes: By using coordinate transformation based on the back tilt angle (β) and in tilt angle (α), a mapping relationship between the three-dimensional spatial coordinates and the calculation plane coordinates is established.

[0021] Preferably, the dynamic calculation of the projection geometric parameters of each link of the steering system on the calculation plane specifically includes: Based on the real-time motion posture of the steering system, the effective length projections of the steering knuckle arm and steering tie rod on the calculation plane are dynamically calculated.

[0022] Preferably, in step S3, the variable load simulation device is a steering damper with an adjustable damping value to simulate steering resistance under different soil conditions. The resistance load simulating the external working conditions also includes the gradual or transient process of simulating the resistance of paddy field soil.

[0023] Preferably, in step S4, the preset ideal steering performance index is the Ackermann angle relationship; The performance deviation is quantified by calculating the root mean square error between the actual steering output value and the ideal steering value calculated based on the Ackermann steering angle relationship.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention discloses a physical simulation system and method for variable steering damping of a lightweight paddy field chassis based on steering tie rod projection. By introducing a physical, programmable variable load simulation device, this complex dynamic load is physically reproduced, thereby greatly improving the simulation fidelity. The physical testing platform is placed in a laboratory, and parameters are modified via software, while the load is controlled via electrical signals. This enables rapid, low-cost iteration of key design parameters and accurate simulation of diverse and repeatable soil conditions (including gradual and transient processes). Through this platform, key parameters of the steering system (such as the length of the steering tie rod) can be rapidly and accurately optimized, allowing the steering system to approximate the ideal Ackermann steering relationship as closely as possible to the inner and outer wheel angles under varying actual working conditions. This significantly improves the handling performance, operational quality, and energy efficiency of the power chassis. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a physical simulation system module for a paddy field lightweight chassis with variable steering damping based on the projection of a steering tie rod, provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of a physical simulation device for a lightweight paddy field chassis with variable steering damping, provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of a physical simulation method for variable steering damping of a paddy field lightweight chassis based on the projection of a steering tie rod, provided by an embodiment of the present invention. Figure 4 This is a three-dimensional structural diagram of the steering system provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of a two-dimensional steering system based on the projection of the steering tie rod, provided in an embodiment of the present invention. Figure 6 This is a schematic diagram of the geometric relationship of the steering outer side model parameters provided in an embodiment of the present invention; Figure 7This is a schematic diagram of the geometric relationship of the steering inner side model parameters provided in an embodiment of the present invention; Explanation of reference numerals in the attached figures: 101. Steering wheel and steering torque sensor; 102. Steering damper; 103. Steering knuckle arm; 104. Steering knuckle arm rotation angle sensor; 105. Steering tie rod; 106. Steering butterfly wheel; 107. Vehicle-mounted embedded microcontroller; 108. Integrated mounting bracket; 109. PC-based host computer; 201. Steering butterfly wheel; 202. Steering tie rod; 203. Steering knuckle arm. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] like Figure 1 As shown, this application provides a physical simulation system for variable steering damping of a paddy field lightweight chassis based on the projection of the steering tie rod, including: The input acquisition module is used to acquire steering command signals from external inputs; The physics simulation module includes: Physical steering linkage mechanism is used to replicate the mechanical motion of a physical steering system; A variable load simulation device, connected to the physical steering linkage mechanism, is used to apply a simulated load according to the steering command signal in order to reproduce the external resistance experienced by the steering system under preset operating conditions. The state sensing module is used to measure the motion state parameters of the physical steering linkage mechanism in real time. The processing control module includes: The built-in kinematic model is established based on three-dimensional geometric parameters through a dimensionality reduction projection method to characterize the mapping relationship between the motion of the physical steering linkage mechanism in three-dimensional space and the two-dimensional plane projection.

[0028] In one embodiment provided in this application, such as Figure 2 As shown, a physical simulation system for variable steering damping of a paddy field light power chassis based on steering tie rod projection modeling is designed. In the system, 101 is the steering wheel and steering torque sensor, 102 is the steering damper, 103 is the steering knuckle arm, 104 is the steering knuckle arm rotation angle sensor, 105 is the steering tie rod, 106 is the steering butterfly wheel, 107 is the vehicle-mounted embedded microcontroller, 108 is the integrated mounting bracket, and 109 is the PC host computer.

[0029] Steering wheel and steering torque sensor 101: As a steering command input component, its output end is connected to the steering butterfly wheel 106 for receiving the steering torque applied by the driver and collecting the torque signal, and transmitting the signal to the vehicle embedded microcontroller 107.

[0030] Steering butterfly wheel 106: Located on the central transmission path of the system, one end of which is fixedly connected to the shaft of the steering wheel and steering torque sensor 101, and the other end is hinged to one end of the left steering tie rod 105 and the right steering tie rod 105 respectively, so as to realize the synchronous transmission of steering torque to the steering tie rods 105 on both sides.

[0031] Steering tie rod 105: includes two rods, one on the left and one on the right, the other end of which is hinged to the steering knuckle arm 103 on the corresponding side, used to transmit the torque transmitted by the steering butterfly 106 to the steering knuckle arm 103.

[0032] Steering knuckle arm 103: There are two, one on the left and one on the right. One end of the knuckle arm is hinged to the steering tie rod 105, and the other end is fixedly connected to the steering damper 102. It is used to convert the force and motion transmitted by the steering tie rod 105 into the deflection motion of the steering damper 102.

[0033] Steering knuckle arm rotation angle sensor 104: One is provided for each of the left and right steering knuckle arms 103. It is installed on the upper end of the rotation shaft of the steering knuckle arm 103 and is used to collect the rotation angle signal of the steering knuckle arm 103 in real time. This signal is equivalent to the steering angle signal of the steering damper 102 and is transmitted to the vehicle embedded microcontroller 107.

[0034] Steering damper 102: Includes two on the left and right sides, which are fixedly connected to the steering knuckle arm 103 and are used to simulate the steering resistance characteristics of the steering wheel under different soil steering resistance conditions.

[0035] The vehicle-mounted embedded microcontroller 107 is connected to the steering wheel and steering torque sensor 101 and the steering knuckle arm rotation angle sensor 104 via signal lines. It is used to receive real-time data collected by the sensors, perform three / two-dimensional kinematic model calculations of the steering system based on the steering tie rod projection, and realize signal communication between various functional components.

[0036] Integrated mounting bracket 108: This is the overall support component of the system. The steering wheel, steering torque sensor 101, steering damper 102, steering knuckle arm 103, steering butterfly wheel 106, and vehicle-mounted embedded microcontroller 107 are all fixedly mounted on the integrated mounting bracket 108 by fasteners to ensure the relative installation position accuracy and movement stability of each component.

[0037] PC-based host computer 109: Connected to the vehicle-mounted embedded microcontroller 107 via a communication line, it is used to monitor the operating status of the simulation system in real time, receive and store various types of data transmitted by the vehicle-mounted embedded microcontroller 107, and generate visual charts from the data to realize the full recording and analysis of the simulation process.

[0038] Steps for optimizing the tie rod length parameter and minimizing the deviation between the actual steering angle and the Ackermann ideal steering angle: Step 1: Determine the parameter range of the steering damper based on the different steering damping properties of the soil; Step 2: Substitute the initial steering damping parameter value, initial steering tie rod length value, steering wheel input data, and fixed roll and caster angle data into the three / two-dimensional kinematic model of the steering system based on the steering tie rod projection to perform numerical calculations to obtain the steering angle of the inner and outer steering wheels; Step 3: Send the calculation results to the steering gear to perform the steering action; Step 4: Measure the steering knuckle arm rotation angle (i.e., the actual output steering angle) in real time, and calculate the root mean square error between the actual vehicle data and the ideal Ackerman steering data. Step 5: Iteratively change the steering damping parameter value and the steering tie rod length value, and substitute them into the kinematic model for numerical calculation; Step 6: Evaluate the optimal length of the steering tie rod under different soil conditions based on the root mean square error; Step 7: Simulation ends, proceed to the next process, namely prototype manufacturing.

[0039] The above steps can optimize the length of the steering tie rod under different soil steering damping conditions, and minimize the deviation between the wheel angle relationship under different soil steering damping and the Ackermann ideal angle relationship.

[0040] Preferably, the variable load simulation device is a programmable steering damper, used to simulate in real time the nonlinear and time-varying steering resistance experienced by the steering system under different soil conditions or mixed conditions by adjusting its damping coefficient.

[0041] In the above scheme, because a programmable steering damper is used, the system can surpass the fixed, linear, or simplified load models in traditional simulations. It can accurately reproduce the nonlinear and time-varying characteristics of real soil resistance, making the simulation results of the steering dynamic response of the entire semi-physical simulation system closer to those of real-world vehicle tests. Since the damping coefficient is programmable, researchers can easily set, switch, and reproduce various extreme or special soil conditions in the laboratory, including mud with different moisture contents and transition zones between soft and hard surfaces. This controllability and repeatability are almost impossible to achieve in real-world vehicle field tests, greatly improving experimental efficiency and the reliability of data comparison.

[0042] Preferably, the physical steering linkage mechanism includes a steering knuckle arm, a steering tie rod, and a steering butterfly; the steering butterfly is used to connect the input acquisition module to the steering tie rod, and the steering tie rod is used to transmit motion and force to the steering knuckle arm to drive the steering knuckle arm to deflect.

[0043] In the above scheme, by using the same core components (knuckle arm, tie rod, and butterfly steering wheel) as the steering system of a physical vehicle, it is ensured that the semi-physical simulation platform is completely consistent with the target design object in terms of geometric constraints and motion transmission paths. This is the foundation for subsequent precise kinematic analysis and parameter optimization. By clearly defining the physical carrier of key geometric parameters such as the steering tie rod, researchers can directly replace or adjust steering tie rods of different lengths on this physical platform during parameter optimization, intuitively testing their impact on steering performance. This ensures that the parameter adjustments in the virtual model correspond one-to-one with the hardware changes in the physical world.

[0044] Preferably, the state sensing module includes a steering knuckle arm rotation angle sensor disposed on the steering knuckle arm rotation axis, used to measure the rotation angle of the steering knuckle arm in real time, and use the angle as a motion state parameter characterizing the actual output of the steering system.

[0045] In the above solution, by directly placing a high-precision sensor on the key output component, the steering knuckle arm, the dynamic response of the system can be captured with zero delay and high accuracy, avoiding errors caused by indirect calculations and ensuring the authenticity and reliability of the feedback data. The real-time angle data provided by this sensor is the direct source for calculating performance deviations. Without this precise feedback, it is impossible to quantitatively evaluate the merits of current parameters (such as the tie rod length), and therefore, effective and automated iterative optimization is also impossible.

[0046] Preferably, the processing control module is an in-vehicle embedded microcontroller; The vehicle-mounted embedded microcontroller is used to acquire sensor data in real time, run the kinematic model, and interact with the physical simulation module.

[0047] In the above scheme, the embedded microcontroller is designed specifically for real-time control applications. Its defined interrupt response and task scheduling mechanisms ensure extremely low closed-loop latency throughout the entire process, from sensor data acquisition to model computation and actuator control. This is crucial for accurately simulating the dynamic response characteristics of steering systems. Integrating data acquisition, model computation, and signal interaction functions into a single MCU chip makes the system structure more compact, reduces potential failure points and delays caused by external wiring and multi-device communication, and improves the stability and reliability of the entire simulation system.

[0048] In one embodiment provided in this application, a physical simulation system for variable steering damping of a paddy field light power chassis based on steering tie rod projection modeling is provided. The system includes a steering wheel and steering torque sensor, steering damper, steering knuckle arm, steering knuckle arm rotation angle sensor, steering tie rod, steering butterfly wheel, a three / two-dimensional kinematic model of the steering system based on steering tie rod projection, an on-board embedded microcontroller, an integrated mounting bracket, and a PC-based host computer.

[0049] Steering wheel and steering torque sensor: used to receive the driver's hand steering torque, measure the magnitude of the hand steering torque and transmit it as an input command to the vehicle-mounted embedded microcontroller; Steering damper: Used to simulate steering wheels under different soil steering resistance conditions; Steering knuckle arm: Used to transmit the force and motion output by the steering gear to the steering damper, causing it to deflect, thereby simulating the steering of the steering wheels; Steering knuckle arm rotation angle sensor: used to measure the rotation angle of the steering knuckle arm, which is equal to the steering angle of the steering damper. This rotation angle is used to simulate the steering angle of the steering wheel. Steering tie rod: When the steering wheel is turned, the steering tie rod transmits the torque generated by the steering gear to the steering knuckle arm through the butterfly wheel, and further transmits the steering torque to the steering damper to simulate the steering of the steering wheel; Steering butterfly: used to connect the steering wheel shaft and the steering tie rod; Three / two-dimensional kinematic model of steering system based on steering tie rod projection: After receiving the steering wheel steering command, the steering angle under different steering tie rod lengths and steering damping magnitudes is calculated based on the real-time collected steering torque, steering knuckle arm rotation angle, and fixed roll and caster angles, and is used for steering gear to carry out steering actions. Automotive embedded microcontroller: used to realize real-time data acquisition from sensors, model calculation, and signal communication between functional components; Integrated mounting bracket: used to fix the various components of the simulation system; PC-based host computer: Used to monitor the operation of the simulation system, record data, and generate charts.

[0050] On the other hand, such as Figure 3 As shown, a physical simulation method for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection is applied to a physical simulation system for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection, including: S1: The kinematic model maps the three-dimensional spatial geometry of the steering system to a low-dimensional computational plane, and dynamically calculates the projection geometric parameters of each link of the steering system on the computational plane according to the preset three-dimensional spatial parameters; S2: Receive steering input command, and use the kinematic model to calculate the theoretical steering output value based on the steering input command and several geometric parameters of the steering system to be optimized; S3: Drive the physical simulation module, which applies a resistance load simulating external working conditions to the physical steering linkage mechanism through a variable load simulation device; S4: The actual steering output value of the physical steering linkage mechanism under the resistance load is measured in real time by the state sensing module, and the actual steering output value is compared with the preset ideal steering performance index to generate a performance deviation; S5: Based on the performance deviation, adjust the geometric parameters of the steering system to be optimized, and repeat steps S2 to S4 until the performance deviation meets the preset conditions.

[0051] In the above approach, by constructing an automated "calculation-execution-measurement-adjustment" closed loop, the method shortens the physical prototype manufacturing and field testing cycle, which originally required weeks or even months, to a multi-scheme iteration that can be completed in a laboratory within hours, greatly improving R&D efficiency. It can systematically traverse multiple combinations of parameters to be optimized under controllable and repeatable load conditions, and uses quantified performance deviations as evaluation criteria, which helps to find the global optimum, rather than potentially getting trapped in local optima like traditional methods. Since most of the parameter iterations are completed on a semi-physical simulation platform, there is no need to manufacture a large number of physical prototypes, significantly saving material costs, manufacturing costs, and testing facility costs.

[0052] Preferably, in step S1, the preset three-dimensional spatial parameters include at least the caster angle (β) and camber angle (α) of the steering kingpin. The process by which the kinematic model maps the three-dimensional spatial geometry of the steering system to the low-dimensional computational plane includes: By using coordinate transformation based on the back tilt angle (β) and in tilt angle (α), a mapping relationship between the three-dimensional spatial coordinates and the calculation plane coordinates is established.

[0053] In the above scheme, the kinematic model accurately incorporates the effects of the kingpin caster angle β and inclination angle α through coordinate transformation. It can accurately describe the dynamic changes in the projection length of the connecting rod on the two-dimensional plane caused by the existence of these three-dimensional angles. This makes the relationship between the inner and outer wheel rotation angles calculated by the model closer to the actual three-dimensional space connecting rod motion results, with a fidelity far higher than that of the two-dimensional model that completely ignores these angles.

[0054] Preferably, the dynamic calculation of the projection geometric parameters of each link of the steering system on the calculation plane specifically includes: Based on the real-time motion posture of the steering system, the effective length projections of the steering knuckle arm and steering tie rod on the calculation plane are dynamically calculated.

[0055] In the above scheme, the kinematic model can dynamically calculate the effective length projection of the link, accurately capturing the geometric nonlinearities present in the steering system. For example, the larger the steering angle, the more significant the change in the projected length may be. This dynamic calculation capability enables the model to accurately predict the angular transmission relationship throughout the entire steering range (from the middle position to the limit position), rather than just approximating it within a small steering angle range.

[0056] Preferably, in step S3, the variable load simulation device is a steering damper with an adjustable damping value to simulate steering resistance under different soil conditions. The resistance load simulating the external working conditions also includes the gradual or transient process of simulating the resistance of paddy field soil.

[0057] The above approach, by simulating gradual and transient processes, enables a thorough evaluation of the robustness, response speed, and stability of the steering system under complex dynamic loads. This is crucial for assessing the performance of the steering system in real, variable paddy field environments, a test that traditional methods struggle to perform. It allows for the identification of potential deficiencies in the steering system's ability to handle sudden load changes (such as shocks, vibrations, and response hysteresis) during the design phase, enabling targeted optimization and significantly improving the reliability and performance of the final product under real, complex operating conditions.

[0058] Preferably, in step S4, the preset ideal steering performance index is the Ackermann angle relationship; The performance deviation is quantified by calculating the root mean square error between the actual steering output value and the ideal steering value calculated based on the Ackermann steering angle relationship.

[0059] In the above scheme, the widely accepted Ackermann angle relationship is adopted as the ideal target, ensuring the correctness of the optimization direction, namely, focusing on reducing tire sideslip, wear, and energy consumption. Using root mean square error (RMSE) as a measure of performance deviation provides an objective and continuous evaluation index. This allows the optimization algorithm (whether automatically or manually adjusted) to efficiently adjust parameters based on the magnitude and trend of the RMSE, converging to the optimal solution as quickly as possible, avoiding the bias of evaluations based on subjective feelings or single operating points.

[0060] In one embodiment provided in this application, the kinematic model employs rigid body planar kinematics, spatial geometric projection, coordinate transformation, dimensionality reduction projection, and kinematic geometry analysis for kinematic modeling. It is assumed that the entire steering system is a spatial linkage system composed of six rigid links connected by ideal hinges, ignoring minute deformations of the links and minute gaps at the connections. First, the mapping relationship between the three-dimensional spatial motion and the two-dimensional planar motion of the steering system is found. Then, the motion of the steering trapezoid projection in the two-dimensional plane is analyzed. Finally, the motion of the steering trapezoid in three-dimensional space is described by combining the mapping relationship and the analysis of the two-dimensional planar motion.

[0061] like Figure 4 and Figure 5 As shown, the steering butterfly 201 is centrally located, with its left side connected to the left steering tie rod 202 via a hinge point, and its right side connected to the right steering tie rod 202 via a hinge point. The other ends of the two steering tie rods 202 are respectively hinged to the steering knuckle arms 203 on the corresponding sides, forming a complete steering transmission link. When a steering command is input through the steering wheel, the steering butterfly 201 rotates around its own central axis by an angle θ, transmitting a push-pull force to the steering knuckle arms 203 through the two steering tie rods 202. This drives the steering knuckle arms 203 to rotate around their rotation axis (with camber angle α and caster angle β), thereby causing the steering damper (simulating the steering wheel) to generate a corresponding steering angle (outer wheel steering angle θ). o Inner wheel rotation angle θ i This enables steering. Throughout the entire transmission process, all components are rigidly connected, and minor deformations and gaps are negligible.

[0062] The steering butterfly wheel 201 is an intermediate connector for power transmission in the steering system, installed at the core transmission position of the steering system, with its center connected to the steering wheel shaft. During movement, this component remains parallel to the xOy plane formed by the chassis's forward direction. Its turning angle θ directly relates to the efficiency of steering torque transmission. Through its own rotation, it converts the steering input from the steering wheel into a pushing or pulling force on the two steering tie rods, making it a key component for transmitting steering commands.

[0063] The steering tie rod 202 consists of a left steering tie rod and a right steering tie rod, both being rigid transmission rods. Both ends are connected to the steering butterfly 201 and the steering knuckle arm 203 via ideal hinges. The left steering tie rod connects the left side of the steering butterfly 201 to the left steering knuckle arm, and the right steering tie rod connects the right side of the steering butterfly 201 to the right steering knuckle arm. Its effective length and projected length during movement (l') are specified. o 、l' i The steering tie rod is one of the core parameters for calculating the three / two-dimensional kinematic model of the steering system. During the steering process, the steering tie rod further transmits the torque from the steering butterfly to the steering knuckle arm, driving the steering knuckle arm to deflect, which in turn drives the steering damper (simulating the steering wheel) to achieve the steering action.

[0064] The steering knuckle arm 203 consists of a left steering knuckle arm and a right steering knuckle arm, both being rigid load-bearing members. One end is hinged to the steering tie rod 202, and the other end is rigidly connected to the steering damper. Its rotation axis has a fixed inclination angle α and caster angle β. The effective length m of the steering knuckle arm and its projected length during movement (m') are also specified. o m' i ) is the related wheel rotation angle (θ) in the kinematic model. o θ i The key parameter of the steering tie rod is to convert the force and motion transmitted by the steering tie rod into the deflection motion of the steering damper, thereby simulating the steering process of the steering wheel.

[0065] The X and Z axes of the coordinate system labels are reference axes of the local coordinate system of the steering system. The X axis is in the same direction as the chassis forward movement, and the Z axis is perpendicular to the horizontal plane where the X axis is located. They are used to help illustrate the spatial positional relationship of each component and provide an intuitive reference for understanding the mapping relationship between the three-dimensional spatial motion of the steering system and the two-dimensional planar projection.

[0066] According to the right-hand rule, establish a coordinate system O-xyz with the midpoint of the perpendiculars from the left and right kingpins to the two pivot points as the origin O, and the chassis forward direction as the x-axis. Establish another coordinate system O with the pivot point of the perpendicular from the steering knuckle to the kingpin shaft as the origin O. o -x o y o z o and O i -x i y i z i First, for O o -x o y o z o and O i -x i y i z i Perform a coordinate transformation based on the backslope angle β, and then perform a coordinate transformation based on the inclination angle α to obtain a new coordinate system O. o -x' o y' o z' o and O i -x' i y' i z' i .

[0067] like Figure 6 and Figure 7 As shown, within the xOy projection plane, the steering butterfly disk rotates through an angle θ, and the position of the steering trapezoidal member changes from O. o A o B oO b B i A i O i Move to O o A' o B' o O b B' i A' i O i The outer steering wheel (outer steering damper) turns through an angle θ o The inner steering wheel (inner steering damper) turns through an angle θ i During the movement, the butterfly disk remains parallel to the xOy plane; therefore, the projected length B' of the butterfly disk is... o O b and B' i O b This is a fixed value. The boom rotates, and because the boom's rotation axis has an inclination angle α and a backclination angle β, the effective length projection m' of the boom is... o and m' i (A' o O o and A' i O i ), the effective length projection l' of the tie rod o and l' i (A' o B' o and A' i B' i The value of the steering trapezoid changes with the movement of the connecting rod. Therefore, to complete the transformation from three-dimensional spatial motion to two-dimensional planar motion, it is necessary to first find the projection m' of the effective length of the outer joint arm and the outer tie rod. o and l' o With the outer wheel rotation angle θ o The relationship between the inner arm and the projection m' of the effective length of the inner tie rod. i and l' i With the outer wheel rotation angle θ i The relationship.

[0068] Because the steering knuckle arm is rigidly and vertically connected to other components, the hinge point (point A') between the steering knuckle arm and the steering tie rod in three-dimensional space... o and point A' i It can only perform circular motion around the arm axis. After coordinate transformation, point A' is obtained. o and point A' i In spatial coordinate system O o -x o y o z o The coordinates of O i -x i yi z i The coordinates are given by the following formula.

[0069]

[0070] In the formula: m is the effective length of the steering knuckle arm; β is the caster angle; α is the camber angle; σ o It is the outer steering knuckle arm and O o x' o The included angle of the axes; σ i It is the inner steering knuckle arm and O i x' i The included angle of the axis.

[0071] The two-dimensional kinematic model is as follows:

[0072] In the formula: φ is the base angle of the turning trapezoid. θ o θ is the steering angle of the outer steering wheel. i denoted as φ, where K is the wheelbase and L is the track width. l is the effective length of the steering tie rod; h is the perpendicular distance from the butterfly lever to the intersection of the pivot arm and the kingpin. ψ is the base angle of the isosceles triangle with a fixed vertex. δ1 and δ2 are auxiliary angles used for motion analysis. o It is the projection of the effective length of the outer steering knuckle arm; l' o It is the projection of the effective length of the outer tie rod; l' i Projection of the effective length of the inner horizontal tie rod. L B'oOo These are auxiliary line segments used for motion analysis. s is the distance between the butterfly disc's connecting end and the center of rotation; θ is the rotation angle of the butterfly disc; γ is the angle between the butterfly disc and the side of the isosceles triangle with a fixed vertex. u is the leg length of the isosceles triangle with a fixed vertex.

[0073] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A physical simulation system for variable steering damping of a paddy field lightweight chassis based on the projection of a steering tie rod, characterized in that, include: The input acquisition module is used to acquire steering command signals from external inputs; The physics simulation module includes: Physical steering linkage mechanism is used to replicate the mechanical motion of a physical steering system; A variable load simulation device, connected to the physical steering linkage mechanism, is used to apply a simulated load according to the steering command signal in order to reproduce the external resistance experienced by the steering system under preset operating conditions. The state sensing module is used to measure the motion state parameters of the physical steering linkage mechanism in real time. The processing control module includes: The built-in kinematic model is established based on three-dimensional geometric parameters through a dimensionality reduction projection method to characterize the mapping relationship between the motion of the physical steering linkage mechanism in three-dimensional space and the two-dimensional plane projection.

2. The physical simulation system for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection according to claim 1, characterized in that, The variable load simulation device is a programmable steering damper used to simulate the nonlinear and time-varying steering resistance of the steering system under different soil conditions or mixed conditions in real time by adjusting its damping coefficient.

3. The physical simulation system for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection according to claim 1, characterized in that, The physical steering linkage mechanism includes a steering knuckle arm, a steering tie rod, and a steering butterfly; the steering butterfly is used to connect the input acquisition module to the steering tie rod, and the steering tie rod is used to transmit motion and force to the steering knuckle arm to drive the steering knuckle arm to deflect.

4. The physical simulation system for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection according to claim 3, characterized in that, The state sensing module includes a steering knuckle arm rotation angle sensor disposed on the steering knuckle arm rotation axis, used to measure the rotation angle of the steering knuckle arm in real time, and use the angle as a motion state parameter characterizing the actual output of the steering system.

5. The physical simulation system for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection according to claim 1, characterized in that, The processing and control module is an in-vehicle embedded microcontroller; The vehicle-mounted embedded microcontroller is used to acquire sensor data in real time, run the kinematic model, and interact with the physical simulation module.

6. A physical simulation method for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection, applied to the physical simulation system for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection as described in claims 1-5, characterized in that, include: S1: The kinematic model maps the three-dimensional spatial geometry of the steering system to a low-dimensional computational plane, and dynamically calculates the projection geometric parameters of each link of the steering system on the computational plane according to the preset three-dimensional spatial parameters; S2: Receive steering input command, and use the kinematic model to calculate the theoretical steering output value based on the steering input command and several geometric parameters of the steering system to be optimized; S3: Drive the physical simulation module, which applies a resistance load simulating external working conditions to the physical steering linkage mechanism through a variable load simulation device; S4: The actual steering output value of the physical steering linkage mechanism under the resistance load is measured in real time by the state sensing module, and the actual steering output value is compared with the preset ideal steering performance index to generate a performance deviation; S5: Based on the performance deviation, adjust the geometric parameters of the steering system to be optimized, and repeat steps S2 to S4 until the performance deviation meets the preset conditions.

7. The physical simulation method for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection according to claim 6, characterized in that, In step S1, the preset three-dimensional spatial parameters include at least the caster angle (β) and inclination angle (α) of the steering kingpin. The process by which the kinematic model maps the three-dimensional spatial geometry of the steering system to the low-dimensional computational plane includes: By using coordinate transformation based on the back tilt angle (β) and in tilt angle (α), a mapping relationship between the three-dimensional spatial coordinates and the calculation plane coordinates is established.

8. The physical simulation method for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection according to claim 7, characterized in that, The dynamic calculation of the projection geometric parameters of each link of the steering system on the calculation plane specifically includes: Based on the real-time motion posture of the steering system, the effective length projections of the steering knuckle arm and steering tie rod on the calculation plane are dynamically calculated.

9. The physical simulation method for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection according to claim 6, characterized in that, In step S3, the variable load simulation device is a steering damper with an adjustable damping value to simulate steering resistance under different soil conditions. The resistance load simulating the external working conditions also includes the gradual or transient process of simulating the resistance of paddy field soil.

10. The physical simulation method for variable steering damping of a paddy field lightweight chassis based on steering tie rod projection according to claim 6, characterized in that, In step S4, the preset ideal steering performance index is the Ackermann angle relationship; The performance deviation is quantified by calculating the root mean square error between the actual steering output value and the ideal steering value calculated based on the Ackermann steering angle relationship.

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