A method and system for in-situ testing of mechanical properties of lunar soil on a screen wheel

Abstract

The present application relates to the technical field of lunar exploration, and provides a kind of screen wheel lunar soil mechanical property in-situ test method, comprising: S1: ground establishes lunar vehicle screen wheel equivalent parameter, drive current-torque correlation, wheel positive pressure calculation model;S2: carry out simulated lunar soil wheel excavation test, inversion lunar soil mechanical parameter, through standard test comparison correction inversion model;S3: find suitable lunar soil detection point through panoramic camera of lunar vehicle;S4: control lunar vehicle to move to detection position, lock five wheels, drive single wheel at specified speed to carry out lunar soil excavation, real-time acquisition telemetry parameter;S5: take photograph to excavation soil pile and excavation pit through vehicle-mounted camera;S6: based on the photographing data, obtain the lunar soil angle of repose, and substitute telemetry parameter into the inversion model established on the ground, to obtain the cohesion of lunar soil by inversion.The lunar surface simulation is based on the lunar soil excavation soil mechanics test process of Bekker theory, and the in-situ test of lunar soil mechanical properties is realized through data inversion.

Description

Technical Field

[0001] This invention relates to the technical field of lunar exploration, and in particular to an in-situ testing method and system for the mechanical properties of lunar soil using a screen wheel based on the theory of wheel-type tunneling. Background Technology

[0002] Lunar exploration, as one of the core research directions in the field of deep space exploration, is an important indicator of a country's aerospace technology level. my country has always attached great importance to the planning and implementation of its lunar exploration program. After years of technological breakthroughs and engineering practice, it successfully completed the "three-step" strategic goal of lunar exploration in 2020, achieving a series of major breakthroughs including lunar orbiting, soft landing and rover exploration, and lunar sample return, propelling my country's lunar exploration program into a new stage of development. Building on this foundation, the focus of my country's lunar exploration work has gradually shifted from cultivating and building basic exploration capabilities in the mid- and low-latitude regions of the moon to a strategic shift towards in-depth scientific research in the lunar polar regions and the comprehensive development and utilization of lunar resources. Continuous efforts are being made to deepen multi-dimensional and high-precision exploration of the lunar polar regions, striving to further explore their scientific value and resource potential, and contributing to the sustainable development of my country's deep space exploration program.

[0003] In the overall development plan for lunar polar exploration and resource development and utilization in my country, lunar mobile exploration and in-situ utilization of lunar regolith resources are the two primary core objectives for the comprehensive development and utilization of lunar resources at this stage. The smooth progress and implementation of both are inextricably linked to the mechanical properties of the lunar surface and regolith. As a key indicator reflecting the physical and mechanical characteristics of lunar regolith, the accuracy of lunar regolith mechanical parameters directly determines the overall design rationality of the lunar mobile exploration system and the scientific nature of the rover's on-orbit path planning. It also plays a decisive role in the research and development and functional adaptability of related equipment for in-situ utilization of lunar regolith resources, and is the core basic data supporting all aspects of lunar polar exploration and resource development and utilization.

[0004] However, current domestic and international research on lunar polar regions is still in a phase of continuous exploration. Due to the unique geographical environment and technical challenges of the lunar polar regions, accurate, comprehensive, and reliable mechanical parameters of lunar regolith have not yet been obtained. This lack of crucial data has become a significant technical bottleneck hindering the smooth progress of my country's mobile exploration of the lunar polar regions, in-situ utilization of lunar regolith resources, and the planning and construction of subsequent lunar research stations. Conducting in-situ measurements of lunar regolith mechanical parameters in the lunar polar regions has crucial engineering practical significance and scientific research value. Firstly, it can provide accurate and effective parameter input for the research and development of lunar rover systems, supporting researchers in carrying out targeted design of the rover system based on the unique mechanical properties of lunar soil in the lunar polar regions, and improving the adaptability of the rover system to the lunar polar environment.

[0005] Secondly, it can provide solid and powerful data support for the on-orbit path planning of the rover, help researchers accurately predict the lunar surface driving conditions, effectively avoid malfunctions such as excessive sinking, slipping, and rollover during the rover's travel on the lunar surface in the polar regions, and ensure the safe and smooth implementation of the lunar surface mobile exploration mission.

[0006] Third, it can provide scientific and systematic theoretical guidance for the design, research and development and optimization of equipment for in-situ utilization of lunar soil during the construction of lunar research stations, greatly improve the compatibility and working efficiency of related equipment with polar lunar soil, and help achieve the goal of in-situ utilization of lunar soil resources.

[0007] In summary, in-situ measurements of lunar soil mechanical parameters in the lunar polar regions are of irreplaceable importance for comprehensively enhancing my country's lunar exploration capabilities and promoting the orderly and in-depth development of scientific research and resource development and utilization in the lunar polar regions.

[0008] During the implementation of lunar exploration projects, the launch weight of spacecraft is limited by factors such as rocket carrying capacity and launch costs, and there are always strict and clear performance requirements. This is also a core constraint that must be considered in the research and development and planning of lunar exploration equipment. Due to the direct constraint of this key factor, my country has not yet planned the development of dedicated equipment or instruments for in-situ measurement of lunar regolith mechanical parameters, and there is currently no dedicated testing equipment to support in-situ measurement of lunar regolith mechanical parameters in the lunar polar regions.

[0009] Faced with the dual challenges of a severe lack of accurate mechanical parameters of lunar regolith in the current lunar polar regions and the absence of a development plan for dedicated lunar surface testing equipment, this application, based on the existing functional performance, technical specifications, and workflows of my country's polar lunar rovers, fully explores the potential testing value of existing lunar exploration equipment and maximizes its functional effectiveness. It aims to provide a method and process for in-situ testing of lunar regolith characteristics using a screen wheel based on wheeled tunneling theory. By rationally utilizing existing lunar rover equipment, this method solves the problem of in-situ measurement of lunar regolith mechanical parameters in the absence of dedicated testing equipment, providing crucial and reliable lunar regolith mechanical data support for my country's lunar polar exploration and resource development, and filling the current technological gap in the accurate measurement of lunar regolith mechanical parameters in the lunar polar regions. Summary of the Invention

[0010] To address the aforementioned problems, the present invention aims to provide an in-situ testing method and system for the mechanical properties of lunar soil using a screen wheel. In the absence of dedicated testing equipment for lunar soil mechanical properties, and based on the existing functional performance and workflow of my country's polar lunar rover, the method utilizes existing lunar rover wheels as testing tools to simulate the lunar soil mechanics testing process based on Bekker theory on the lunar surface. Through data inversion, in-situ testing of lunar soil mechanical properties is achieved.

[0011] The above-mentioned objective of this invention is achieved through the following technical solutions: A method for in-situ testing of the mechanical properties of lunar soil using a screen wheel includes: S1: Ground Modeling and Calibration Stage: The equivalent parameters of the lunar rover's screen wheel, the correlation between driving current and torque, and the calculation model of wheel normal pressure are established on the ground, and the ground calibration is completed; S2: Ground test and model correction phase: Conduct simulated lunar soil wheel tunneling test, invert lunar soil mechanical parameters, correct the inversion model through standard test comparison, and establish an in-situ lunar surface exploration model; S3: Lunar exploration site selection stage: Using the lunar rover's panoramic camera to find suitable lunar soil exploration sites; S4: Lunar Surface Tunneling Test Phase: Control the lunar rover to move to the exploration location, lock the five wheels, drive a single wheel at a specified speed to tunnel through the lunar soil, and collect telemetry parameters in real time; S5: Lunar surface data acquisition phase: Control the lunar rover to move away from the excavation area and take pictures of the excavated soil pile and excavation pit through the onboard camera; S6: Lunar surface parameter inversion stage: Based on the photographic data, the lunar soil accumulation angle is obtained, and the telemetry parameters are substituted into the inversion model established on the ground to obtain the lunar soil cohesion and complete the in-situ test of the lunar soil mechanical properties.

[0012] Furthermore, in step S1, the ground modeling and calibration stage specifically includes: S11: Establish the equivalent radius r of the lunar rover's screen wheel and the solid wheel on the ground. s With equivalent width b s And it was verified through wheel bench tests; S12: Ground measurements establish the correlation curve between the drive current and torque of the screen wheel on the lunar rover at different temperatures: T=f(I), where T is the wheel torque and I is the drive current. S13: Analyze and calculate the normal force of each wheel by using the vehicle body attitude parameters and the angle parameters of each joint of the motion system. The normal force of each wheel satisfies the formula Fn=f(m,α,β,γ,...), where m is the mass of the lunar rover, and α, β, and γ are the vehicle body attitude parameters and the angle parameters of each joint of the motion system.

[0013] Furthermore, in step S2, the ground test and model correction stage specifically includes: S21: Using a six-wheel independent drive mobile system with main and auxiliary rocker arms in the same state as the lunar surface, a ground-simulated lunar soil wheel tunneling test was carried out. The corresponding current, voltage, vehicle body attitude and joint angles were recorded and the wheel sinking depth z before and after the vehicle body test was analyzed. S22: Take photos of the soil deposits generated by the wheel excavation, and analyze the corresponding angle of accumulation through image processing. ; S23: Based on Coulomb's law of deformation and a wheel-soil contact model for screen wheels, the relationship between the wheel flange shear stress and other wheel parameters during excavation is derived, and the lunar soil cohesion c is simulated by inversion. The relationship satisfies the following formula: In the formula, T is the wheel torque, and F is the torque of the wheel. N For the vertical load on the wheel, Let r be the angle of internal friction of the lunar soil. s Let b be the equivalent radius of the wheel. s For equivalent width, The contact angle between the soil and the wheel. Where c is the depth of subsidence and c is the cohesive force of the lunar regolith. S24: The cohesion c of the simulated lunar soil under the test conditions was tested using a standard soil mechanics measuring instrument, and the angle of accumulation of the soil piled up by wheel excavation was measured. ; S25: The mobile system underwent tunneling tests and standard tests on simulated lunar soil with different mechanical properties, verifying the lunar soil cohesion c and angle of repose. The measured values ​​and the inverted values ​​were compared and analyzed to correct the lunar soil parameter inversion model; S26: Establish lunar regolith cohesion (c) and angle of repose based on lunar rover telemetry parameters including voltage, drive current, rover attitude, and track marks. An accurate model for in-situ detection.

[0014] In addition, in step S3, the lunar rover is a polar lunar rover equipped with a main and auxiliary rocker arm type six-wheel independent drive mobile system, and the panoramic camera is used to select an undisturbed lunar soil area as a probe point; Step S4 specifically includes: S41: Control the movement system to the detection position, record the corresponding vehicle body posture and the angle of each joint of the movement system, and calculate the normal pressure of each wheel. S42: Select an area of ​​lunar soil that has not been disturbed, and perform a five-wheel lock-on operation and a one-wheel excavation operation at a specified speed. Specifically, the left rear wheel will dig while the other five wheels are locked. S43: Real-time recording of telemetry parameters, including motor temperature, left rear wheel motor current, vehicle body IMU data, and joint telemetry angle values.

[0015] In addition, in step S5, the vehicle-mounted camera is used to take pictures of the soil piles and excavation pits generated during the excavation, and the picture data is used for the subsequent extraction of lunar soil deposition angle; Step S6 specifically includes: Step S6 specifically includes: S61: Analyze the photos taken from the rover and obtain the lunar surface soil accumulation angle through image processing. ; S62: Read telemetry parameters including lunar rover voltage, wheel drive current, rover attitude, and telemetry angle values ​​of moving joints, and substitute the telemetry parameters into the lunar soil cohesion c-inversion model based on lunar rover telemetry parameters voltage, drive current, rover attitude, and wheel tracks. S63: Combined with the obtained lunar soil accumulation angle The cohesion c of lunar soil based on lunar surface measurement parameters was obtained by inversion, and the in-situ test of lunar soil mechanical properties was completed.

[0016] In addition, the method relies on the lunar rover's main and auxiliary rocker arm type six-wheel independent drive mobile system. The mobile system has the ability to acquire the drive wheel current, voltage, rover attitude and track images in real time, without the need for additional in-situ measurement equipment for lunar soil mechanical parameters. S1-S2 are ground-based methods and procedures used to establish and verify the lunar soil mechanical parameter inversion model; S3-S6 are lunar surface testing procedures used to apply the ground-verified model to in-situ measurements of lunar soil mechanical parameters in the lunar polar regions.

[0017] In addition, in step S21, the wheel excavation test is used to simulate the lunar surface soil excavation conditions, and the wheel sinking depth z before and after the test is obtained by analyzing the vehicle body posture and wheel tracks. In addition, in step S25, the modified lunar soil parameter inversion model is used to eliminate the difference between the ground simulation test and the actual working conditions on the lunar surface, and improve the accuracy of in-situ measurements on the lunar surface. In addition, in step S4, the specified speed of single-wheel tunneling is preset based on the performance of the lunar rover's drive system and the lunar soil conditions, and the five-wheel locking is used to ensure the stability of the vehicle's attitude during tunneling and to avoid interfering with the test data.

[0018] A screen wheel in-situ testing system for lunar soil mechanical properties, used to perform the above-described screen wheel in-situ testing method, includes: Ground modeling and calibration module: The equivalent parameters of the lunar rover's screen wheel, the correlation between driving current and torque, and the calculation model of wheel normal force are established on the ground to complete the ground calibration; Ground test and model correction module: Conduct simulated lunar soil wheel tunneling test, invert lunar soil mechanical parameters, correct the inversion model through standard test comparison, and establish an in-situ lunar surface exploration model; Lunar exploration site selection module: Uses the lunar rover's panoramic camera to find suitable lunar soil exploration sites; Lunar surface excavation test module: Controls the lunar rover to move to the exploration location, locks five wheels, drives a single wheel at a specified speed to excavate lunar soil, and collects telemetry parameters in real time; Lunar data acquisition module: controls the lunar rover to move away from the excavation area and takes pictures of the excavated soil pile and excavation pit through the onboard camera; Lunar surface parameter inversion module: Based on the image data, the lunar soil deposition angle is obtained, and the telemetry parameters are substituted into the inversion model established on the ground to obtain the lunar soil cohesion and complete the in-situ test of the lunar soil mechanical properties.

[0019] A computer device, characterized in that it includes a memory and one or more processors, wherein the memory stores computer code, and when the computer code is executed by the one or more processors, causes the one or more processors to perform the method as described above.

[0020] A computer-readable storage medium, characterized in that the computer-readable storage medium stores computer code, which, when executed, is performed as described above.

[0021] Compared with the prior art, the present invention has at least one of the following beneficial effects: (1) No need to add special equipment, and make full use of existing hardware resources: This invention relies on the existing hardware such as the main and auxiliary rocker arm type six-wheel independent drive mobile system, panoramic camera, and vehicle-mounted camera that have been configured on China's polar lunar rover to realize in-situ measurement of lunar soil mechanical parameters. There is no need to develop and launch special testing equipment for lunar soil mechanical properties. This completely avoids core constraints such as launch weight and mission cost, and solves the problem of measuring lunar soil mechanical parameters in the lunar polar region without special testing equipment.

[0022] (2) Filling the gap in the measurement technology of lunar soil mechanical parameters in the lunar polar region: In view of the current situation that there are no accurate and reliable lunar soil mechanical parameters in the lunar polar region at home and abroad, this invention realizes the accurate in-situ measurement of core mechanical parameters such as cohesion and packing angle of lunar soil in the lunar polar region through the complete process of "ground modeling verification - in-situ application on the lunar surface", which provides key basic data support for lunar polar region exploration and resource development.

[0023] (3) High measurement accuracy and strong model robustness: This invention uses ground multi-condition simulation lunar soil tunneling test and standard mechanical test comparison to iteratively correct the lunar soil parameter inversion model, eliminating the difference between ground simulation conditions and actual lunar surface conditions, and greatly improving the accuracy and reliability of in-situ lunar surface measurement; at the same time, based on the Coulomb deformation law and the mechanical formula derived from the screen wheel exclusive wheel-soil contact model, it fully adapts to the structural characteristics of the screen wheel, ensuring the accuracy of parameter inversion.

[0024] (4) The entire process is adapted to the lunar rover's on-orbit mission, and the engineering feasibility is strong: The lunar surface testing process of this invention is completely in line with the existing working mode of the lunar rover. Through the operation of "five-wheel locking and single-wheel specified speed tunneling", the vehicle body attitude is kept stable during the tunneling process, and the test is avoided from interfering with the normal exploration mission of the lunar rover. All telemetry data (current, voltage, attitude, angle, and photos) are conventional data collected by the lunar rover. There is no need to add a new data acquisition link. The engineering implementation is simple and the operation is strong.

[0025] (5) Wide range of applications, supporting lunar exploration missions in multiple fields: The lunar soil mechanical parameters obtained by this invention can directly provide core inputs for the targeted design of lunar rover systems, on-orbit path planning of rover (avoiding failures such as excessive subsidence, slippage, and rollover), and design of lunar soil in-situ utilization equipment for lunar research stations. It fully supports multiple fields of missions such as lunar polar region mobile exploration, resource development, and research station construction, and significantly enhances my country's comprehensive lunar exploration capabilities.

[0026] (6) Standardized testing process with strong scalability: The entire process of ground modeling, model correction and lunar surface testing of this invention forms a standardized technical system that can be adapted to lunar rover screen wheels with different structures and parameters. At the same time, it can be extended to the in-situ measurement of the mechanical properties of lunar soil / astrosomatic soil of other extraterrestrial bodies such as Mars and asteroids, and has good technical versatility and scalability.

[0027] (7) High data utilization rate and maximized exploration value: This invention fully explores the potential value of conventional telemetry data, track images, and onboard photography data of lunar rovers, and deeply integrates the mobile exploration function of lunar rovers with the mechanical testing function of lunar soil. Without increasing the task burden, it maximizes the exploration value of lunar rovers and provides multi-dimensional data support for scientific research in the lunar polar regions. Attached Figure Description

[0028] Figure 1 This is an overall flowchart of the in-situ testing method for the mechanical properties of lunar soil using a screen wheel according to the present invention; Figure 2 This is a schematic diagram of the tunneling process of the present invention; Figure 3 This is a diagram illustrating the wheel excavation process of the present invention. Figure 4 This is a structural diagram of the in-situ testing system for the mechanical properties of lunar soil using a screen wheel, as described in this invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0031] First Embodiment like Figure 1 As shown, this embodiment provides an in-situ testing method for the mechanical properties of lunar soil using a screen wheel, including: S1: Ground modeling and calibration stage: The equivalent parameters of the lunar rover's screen wheel, the correlation between driving current and torque, and the calculation model of wheel normal pressure are established on the ground, and the ground calibration is completed.

[0032] In step S1, the ground modeling and calibration stage specifically includes: S11: Establish the equivalent radius r of the lunar rover's screen wheel and the solid wheel on the ground. s With equivalent width b s And it was verified through wheel bench tests; S12: Ground measurements establish the correlation curve between the drive current and torque of the screen wheel on the lunar rover at different temperatures: T=f(I), where T is the wheel torque and I is the drive current. S13: Analyze and calculate the normal force of each wheel by using the vehicle body attitude parameters and the angle parameters of each joint of the motion system. The normal force of each wheel satisfies the formula Fn=f(m,α,β,γ,...), where m is the mass of the lunar rover, and α, β, and γ are the vehicle body attitude parameters and the angle parameters of each joint of the motion system.

[0033] The ground modeling and calibration stage is the preliminary and fundamental preparation stage for the entire in-situ testing of the mechanical properties of lunar soil using a screen wheel. Its core is to build a precise foundation for parameter calculation and data conversion for subsequent ground experiments and in-situ lunar surface tests. Through a series of ground operations, key parameters are defined, correlation models are established, and validity is verified to ensure that various types of collected data in subsequent tests can be accurately converted into the relevant parameters required for mechanical analysis.

[0034] This phase will first clarify the equivalent radius and equivalent width of the lunar rover's screen wheel and the solid wheel. Simultaneously, wheel bench tests will be conducted to verify the effectiveness of these two equivalent parameters, resolving parameter adaptation issues arising from the screen wheel's unique structure. Next, ground measurements will be used to establish the correlation curves between the screen wheel's driving current and the wheel's torque under different temperature conditions, enabling the precise conversion of current data directly collected by the lunar rover into the crucial mechanical analysis data of wheel torque. Finally, combining the rover's attitude parameters and the angle parameters of each joint in the motion system, the calculation method for the normal pressure of each wheel will be analyzed and derived. This will allow for the quantitative calculation of the wheel's vertical load using attitude and angle data obtained from conventional remote sensing by the lunar rover, providing core basic parameters and data calculation basis for the inversion of lunar soil mechanical parameters in subsequent tunneling tests.

[0035] S2: Ground test and model correction phase: Conduct simulated lunar soil wheel tunneling test, invert lunar soil mechanical parameters, correct the inversion model through standard test comparison, and establish an in-situ lunar surface exploration model.

[0036] In step S2, the ground test and model correction phase specifically includes: S21: Using a six-wheel independent drive mobile system with main and auxiliary rocker arms in the same state as the lunar surface, a ground-simulated lunar soil wheel tunneling test was carried out. The corresponding current, voltage, vehicle body attitude and joint angles were recorded and the wheel sinking depth z before and after the vehicle body test was analyzed. S21: Using a six-wheel independent drive mobile system with main and auxiliary rocker arms in the same state as the lunar surface, a ground-simulated lunar soil wheel tunneling test was carried out. The corresponding current, voltage, vehicle body attitude and joint angles were recorded and the wheel sinking depth z before and after the vehicle body test was analyzed. S22: Take photos of the soil deposits generated by the wheel excavation, and analyze the corresponding angle of accumulation through image processing. ; S23: Based on Coulomb's law of deformation and a wheel-soil contact model for screen wheels, the relationship between the wheel flange shear stress and other wheel parameters during excavation is derived, and the lunar soil cohesion c is simulated by inversion. The relationship satisfies the following formula: In the formula, T is the wheel torque, and F is the torque of the wheel. N For the vertical load on the wheel, Let r be the angle of internal friction of the lunar soil. s Let b be the equivalent radius of the wheel. s For equivalent width, The contact angle between the soil and the wheel. Where c is the depth of subsidence and c is the cohesive force of the lunar regolith. S24: The cohesion c of the simulated lunar soil under the test conditions was tested using a standard soil mechanics measuring instrument, and the angle of accumulation of the soil piled up by wheel excavation was measured. ; S25: The mobile system underwent tunneling tests and standard tests on simulated lunar soil with different mechanical properties, verifying the lunar soil cohesion c and angle of repose. The measured values ​​and the inverted values ​​were compared and analyzed to correct the lunar soil parameter inversion model; S26: Establish lunar regolith cohesion (c) and angle of repose based on lunar rover telemetry parameters including voltage, drive current, rover attitude, and track marks. An accurate model for in-situ detection.

[0037] The ground test and model correction phase is the core link connecting ground basic modeling and lunar in-situ testing. The core is to complete the inversion of lunar soil mechanical parameters through tunneling tests simulating lunar working conditions, and then verify through standard tests and iterative correction under multiple working conditions to establish an accurate inversion model adapted to actual lunar exploration, providing reliable model support for lunar testing.

[0038] This phase first employs a lunar rover movement system identical to that on the lunar surface to conduct wheel-driven excavation tests in simulated lunar soil. Various test data are recorded and analyzed to determine the wheel subsidence depth, thus recreating the realistic excavation conditions on the lunar surface. Next, the excavated soil deposits are photographed, and the angle of repose is obtained through image processing. Then, relying on Coulomb's law of deformation and a specialized screen wheel-soil contact model, relevant mechanical parameter relationships are derived, and the cohesion of the simulated lunar soil is calculated. The mechanical analysis of the wheel-soil contact is referenced... Figure 3 Subsequently, the cohesion and angle of accumulation of the simulated lunar soil under this working condition were measured using a standard soil mechanics measuring instrument to obtain accurate standard reference values. Then, tunneling tests and standard tests were repeated in simulated lunar soil with different mechanical properties. The inverted values ​​and measured values ​​of the parameters were compared and analyzed to correct the lunar soil parameter inversion model, eliminate the difference between the ground simulation and the actual working conditions on the lunar surface, and improve the accuracy of the model. Finally, based on the telemetry parameters that can be collected on the lunar surface by the lunar rover, an accurate model of lunar soil cohesion and angle of accumulation that can be used for in-situ exploration on the lunar surface was established to prepare the model for subsequent actual lunar surface tests.

[0039] S3: Lunar exploration site selection stage: Using the lunar rover's panoramic camera to find suitable lunar soil exploration sites.

[0040] In step S3, the lunar rover is a polar lunar rover equipped with a main and auxiliary rocker arm type six-wheel independent drive mobile system, and the panoramic camera is used to select an undisturbed lunar regolith area as a probe point.

[0041] The lunar exploration site selection phase is a preliminary step in the in-situ lunar testing. Its core purpose is to select areas that meet the testing requirements for subsequent lunar regolith excavation tests, ensuring the authenticity and validity of the measured lunar regolith mechanical parameters. This phase relies on the panoramic camera carried by the polar rover, equipped with a six-wheeled independent drive mobile system with main and auxiliary rocker arms. Utilizing the panoramic camera's superior field of view, the surrounding lunar environment is observed, with a focus on selecting pristine lunar regolith areas that have not been damaged by the rover's movement or disturbance as exploration sites. This avoids distortion of measurement parameters due to damage to the lunar regolith structure, laying the foundation for accurate subsequent lunar regolith excavation tests.

[0042] S4: Lunar Surface Tunneling Test Phase: Control the lunar rover to move to the exploration location, lock the five wheels, drive a single wheel at a specified speed to tunnel through the lunar soil, and collect telemetry parameters in real time.

[0043] The patrol vehicle's operation process, telemetry data acquisition, and parameter inversion logic in this embodiment are as follows: Figure 2 As shown, the entire test process is divided into three core modules: rovers' actions, telemetry data acquisition, and inversion parameter calculation. First, the rovers perform actions such as finding a suitable location, digging with the left rear wheel while locking the other five wheels, driving away from the location, and taking photos. Simultaneously, telemetry data such as motor temperature, left rear wheel motor current, vehicle IMU data, joint telemetry angle values, and photos taken after the digging experiment are collected. Finally, the rear four-wheel drive torque, wheel sinking depth Z, and wheel vertical load F are obtained through data inversion. N Core parameters such as the soil angle of repose ϕ were used to calculate the mechanical parameters of lunar soil in conjunction with the excavation experimental model.

[0044] In step S4, the specified speed for single-wheel tunneling is preset based on the performance of the lunar rover's drive system and the lunar soil conditions. Five-wheel locking is used to ensure the stability of the vehicle's attitude during tunneling and to avoid interfering with the test data.

[0045] Step S4 specifically includes: S41: Control the movement system to the detection position, record the corresponding vehicle body posture and the angle of each joint of the movement system, and calculate the normal pressure of each wheel. S42: Select an area of ​​lunar soil that has not been disturbed, and perform a five-wheel lock-on operation and a one-wheel excavation operation at a specified speed. Specifically, the left rear wheel will dig while the other five wheels are locked. S43: Real-time recording of telemetry parameters, including motor temperature, left rear wheel motor current, vehicle body IMU data, and joint telemetry angle values.

[0046] The lunar surface tunneling test phase is a crucial stage for conducting actual tunneling experiments and collecting core test data in situ on the lunar surface. The operation and data acquisition in this phase are closely integrated. Figure 2The demonstrated rover's operational procedures and data inversion logic are based on acquiring real and effective experimental data on the lunar surface through standardized tunneling operations. This data provides support for subsequent inversion of lunar soil mechanical parameters. The first stage involves maneuvering the rover to a selected exploration point, recording the rover's attitude and the angles of each joint in the motion system, and calculating the normal pressure on each wheel to provide fundamental data for mechanical analysis. Subsequently, in an undisturbed lunar soil area, a five-wheel locking and single-wheel tunneling operation is performed. Specifically, the left rear wheel is used as the tunneling wheel, while the other wheels are locked. This ensures the stability of the rover's attitude during tunneling, preventing rover swaying from interfering with the test data. The speed of single-wheel tunneling is preset in advance based on the performance of the rover's drive system and the actual working conditions on the lunar surface. During tunneling, various key telemetry parameters are collected in real time, including motor temperature, motor current of the tunneling wheel, IMU data from the rover body, and telemetry angle values ​​of the motion system joints. These data are crucial for subsequent inversion of lunar soil mechanical parameters.

[0047] S5: Lunar surface data acquisition phase: Control the lunar rover to move away from the excavation area and take pictures of the excavated soil piles and excavation pits using the onboard camera.

[0048] In step S5, the vehicle-mounted camera is used to take pictures of the soil piles and excavation pits generated during the excavation, and the picture data is used for the subsequent extraction of lunar soil deposition angle.

[0049] The lunar surface data acquisition phase is a crucial step in obtaining key visual data during in-situ lunar surface testing. Following the lunar surface excavation test, it provides direct visual evidence for the subsequent extraction of the lunar regolith angle. This phase begins by maneuvering the lunar rover away from the excavated area to avoid secondary disturbance to the excavated soil mounds and craters, preserving the original state of the subjects being photographed. Subsequently, the rover's onboard camera precisely photographs the excavated soil mounds and craters. The acquired clear image data provides direct material for subsequent image processing to extract the core mechanical parameter, the lunar regolith angle, making it a vital data support step for the accurate inversion of lunar regolith mechanical parameters.

[0050] S6: Lunar surface parameter inversion stage: Based on the photographic data, the lunar soil accumulation angle is obtained, and the telemetry parameters are substituted into the inversion model established on the ground to obtain the lunar soil cohesion and complete the in-situ test of the lunar soil mechanical properties.

[0051] Step S6 specifically includes: S61: Analyze the photos taken from the rover and obtain the lunar surface soil accumulation angle through image processing. ; S62: Read telemetry parameters including lunar rover voltage, wheel drive current, rover attitude, and telemetry angle values ​​of moving joints, and substitute the telemetry parameters into the lunar soil cohesion c-inversion model based on lunar rover telemetry parameters voltage, drive current, rover attitude, and wheel tracks. S63: Combined with the obtained lunar soil accumulation angle The cohesion c of lunar soil based on lunar surface measurement parameters was obtained by inversion, and the in-situ test of lunar soil mechanical properties was completed.

[0052] The lunar surface parameter inversion stage is the final step in the entire in-situ testing of lunar soil mechanical properties using the screen wheel. Its core is to combine previously acquired image and telemetry data with a ground-based inversion model to calculate the core mechanical parameters of the lunar soil, ultimately achieving in-situ measurement of its mechanical properties. This stage first involves professional image processing of photos of the excavated soil mounds and craters taken by the rover's camera, accurately extracting the angle of repose of the lunar soil mounds. Next, it organizes and reads various telemetry parameters collected in real-time during the lunar excavation test, including rover voltage, wheel drive current, rover attitude, and telemetry angles of moving joints. Then, the extracted angle of repose and the organized telemetry parameters are substituted into the lunar soil cohesion inversion model established in the ground stage. The model performs relevant calculations, ultimately inverting the measured lunar soil cohesion, thus completing the in-situ testing of the mechanical properties of lunar soil in the entire lunar polar region.

[0053] Furthermore, the method described in this embodiment relies on the lunar rover's main and auxiliary rocker arm type six-wheel independent drive mobile system. The mobile system has the ability to acquire the drive wheel current, voltage, rover attitude and wheel track images in real time, without the need for additional in-situ measurement equipment for lunar soil mechanical parameters. S1-S2 are ground-based methods and procedures used to establish and verify the lunar soil mechanical parameter inversion model; S3-S6 are lunar surface testing procedures used to apply the ground-verified model to in-situ measurements of lunar soil mechanical parameters in the lunar polar regions.

[0054] Second Embodiment like Figure 4 As shown, this embodiment provides a screen wheel in-situ testing system for lunar soil mechanical properties, used to perform the screen wheel in-situ testing method for lunar soil mechanical properties as described in the first embodiment, comprising: Ground modeling and calibration module: The equivalent parameters of the lunar rover's screen wheel, the correlation between driving current and torque, and the calculation model of wheel normal force are established on the ground to complete the ground calibration; Ground test and model correction module: Conduct simulated lunar soil wheel tunneling test, invert lunar soil mechanical parameters, correct the inversion model through standard test comparison, and establish an in-situ lunar surface exploration model; Lunar exploration site selection module: Uses the lunar rover's panoramic camera to find suitable lunar soil exploration sites; Lunar surface excavation test module: Controls the lunar rover to move to the exploration location, locks five wheels, drives a single wheel at a specified speed to excavate lunar soil, and collects telemetry parameters in real time; Lunar data acquisition module: controls the lunar rover to move away from the excavation area and takes pictures of the excavated soil pile and excavation pit through the onboard camera; Lunar surface parameter inversion module: Based on the image data, the lunar soil deposition angle is obtained, and the telemetry parameters are substituted into the inversion model established on the ground to obtain the lunar soil cohesion and complete the in-situ test of the lunar soil mechanical properties.

[0055] A computer-readable storage medium stores computer code that, when executed, performs the methods described above. Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. This program can be stored in a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk, etc.

[0056] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

[0057] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out 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 method for in-situ testing of the mechanical properties of lunar soil using a screen wheel, characterized in that, include: S1: Ground Modeling and Calibration Stage: The equivalent parameters of the lunar rover's screen wheel, the correlation between driving current and torque, and the calculation model of wheel normal pressure are established on the ground, and the ground calibration is completed; S2: Ground test and model correction phase: Conduct simulated lunar soil wheel tunneling test, invert lunar soil mechanical parameters, correct the inversion model through standard test comparison, and establish an in-situ lunar surface exploration model; S3: Lunar exploration site selection stage: Using the lunar rover's panoramic camera to find suitable lunar soil exploration sites; S4: Lunar Surface Tunneling Test Phase: Control the lunar rover to move to the exploration location, lock the five wheels, drive a single wheel at a specified speed to tunnel through the lunar soil, and collect telemetry parameters in real time; S5: Lunar surface data acquisition phase: Control the lunar rover to move away from the excavation area and take pictures of the excavated soil pile and excavation pit through the onboard camera; S6: Lunar surface parameter inversion stage: Based on the photographic data, the lunar soil accumulation angle is obtained, and the telemetry parameters are substituted into the inversion model established on the ground to obtain the lunar soil cohesion and complete the in-situ test of the lunar soil mechanical properties.

2. The in-situ testing method for the mechanical properties of lunar soil using a screen wheel according to claim 1, characterized in that, In step S1, the ground modeling and calibration stage specifically includes: S11: Establish the equivalent radius r of the lunar rover's screen wheel and the solid wheel on the ground. s With equivalent width b s And it was verified through wheel bench tests; S12: Ground measurements establish the correlation curve between the drive current and torque of the screen wheel on the lunar rover at different temperatures: T=f(I), where T is the wheel torque and I is the drive current. S13: Analyze and calculate the normal force of each wheel by using the vehicle body attitude parameters and the angle parameters of each joint of the motion system. The normal force of each wheel satisfies the formula Fn=f(m,α,β,γ,...), where m is the mass of the lunar rover, and α, β, and γ are the vehicle body attitude parameters and the angle parameters of each joint of the motion system.

3. The in-situ testing method for the mechanical properties of lunar soil using a screen wheel according to claim 1, characterized in that, In step S2, the ground test and model correction phase specifically includes: S21: Using a six-wheel independent drive mobile system with main and auxiliary rocker arms in the same state as the lunar surface, a ground-simulated lunar soil wheel tunneling test was carried out. The corresponding current, voltage, vehicle body attitude and joint angles were recorded and the wheel sinking depth z before and after the vehicle body test was analyzed. S22: Take photos of the soil deposits generated by the wheel excavation, and analyze the corresponding angle of accumulation through image processing. ; S23: Based on Coulomb's law of deformation and a wheel-soil contact model for screen wheels, the relationship between the wheel flange shear stress and other wheel parameters during excavation is derived, and the lunar soil cohesion c is simulated by inversion. The relationship satisfies the following formula: In the formula, T is the wheel torque, and F is the torque of the wheel. N For the vertical load on the wheel, Let r be the angle of internal friction of the lunar soil. s Let b be the equivalent radius of the wheel. s For equivalent width, The contact angle between the wheel and the soil. Where c is the depth of subsidence and c is the cohesive force of the lunar regolith. S24: The cohesion c of the simulated lunar soil under the test conditions was tested using a standard soil mechanics measuring instrument, and the angle of accumulation of the soil piled up by wheel excavation was measured. ; S25: The mobile system underwent tunneling tests and standard tests on simulated lunar soil with different mechanical properties, verifying the lunar soil cohesion c and angle of repose. The measured values ​​and the inverted values ​​were compared and analyzed to correct the lunar soil parameter inversion model; S26: Establish lunar regolith cohesion (c) and angle of repose based on lunar rover telemetry parameters including voltage, drive current, rover attitude, and track marks. An accurate model for in-situ detection.

4. The in-situ testing method for the mechanical properties of lunar soil using a screen wheel according to claim 1, characterized in that, Also includes: In step S3, the lunar rover is a polar lunar rover equipped with a main and auxiliary rocker arm type six-wheel independent drive mobile system, and the panoramic camera is used to select an undisturbed lunar soil area as a probe point; Step S4 specifically includes: S41: Control the movement system to the detection position, record the corresponding vehicle body posture and the angle of each joint of the movement system, and calculate the normal pressure of each wheel. S42: Select an area of ​​lunar soil that has not been disturbed, and perform a five-wheel lock-on operation and a one-wheel excavation operation at a specified speed. Specifically, the left rear wheel will dig while the other five wheels are locked. S43: Real-time recording of telemetry parameters, including motor temperature, left rear wheel motor current, vehicle body IMU data, and joint telemetry angle values.

5. The in-situ testing method for the mechanical properties of lunar soil using a screen wheel according to claim 1, characterized in that, Also includes: In step S5, the vehicle-mounted camera is used to take pictures of the soil piles and excavation pits generated during the excavation, and the picture data is used for the subsequent extraction of lunar soil deposition angle; Step S6 specifically includes: S61: Analyze the photos taken from the rover and obtain the lunar surface soil accumulation angle through image processing. ; S62: Read telemetry parameters including lunar rover voltage, wheel drive current, rover attitude, and telemetry angle values ​​of moving joints, and substitute the telemetry parameters into the lunar soil cohesion c-inversion model based on lunar rover telemetry parameters voltage, drive current, rover attitude, and wheel tracks. S63: Combined with the obtained lunar soil accumulation angle The cohesion c of lunar soil based on lunar surface measurement parameters was obtained by inversion, and the in-situ test of lunar soil mechanical properties was completed.

6. The in-situ testing method for the mechanical properties of lunar soil using a screen wheel according to claim 1, characterized in that, Also includes: The method relies on the lunar rover's main and auxiliary rocker arm type six-wheel independent drive mobile system. The mobile system has the ability to acquire the drive wheel current, voltage, rover attitude and wheel track images in real time, without the need for additional in-situ measurement equipment for lunar soil mechanical parameters. S1-S2 are ground-based methods and procedures used to establish and verify the lunar soil mechanical parameter inversion model; S3-S6 are lunar surface testing procedures used to apply the ground-verified model to in-situ measurements of lunar soil mechanical parameters in the lunar polar regions.

7. The in-situ testing method for the mechanical properties of lunar soil using a screen wheel according to claim 1, characterized in that, Also includes: In step S21, the wheel excavation test is used to simulate lunar soil excavation conditions, and the wheel sinking depth z before and after the test is obtained by analyzing the vehicle posture and wheel tracks. In step S25, the modified lunar soil parameter inversion model is used to eliminate the difference between the ground simulation test and the actual working conditions on the lunar surface, and improve the accuracy of in-situ measurements on the lunar surface. In step S4, the specified speed for single-wheel tunneling is preset based on the performance of the lunar rover's drive system and the lunar soil conditions. Five-wheel locking is used to ensure the stability of the vehicle's attitude during tunneling and to avoid interfering with the test data.

8. A screen wheel in-situ testing system for the mechanical properties of lunar soil using a screen wheel as described in any one of claims 1-7, characterized in that, include: Ground modeling and calibration module: The equivalent parameters of the lunar rover's screen wheel, the correlation between driving current and torque, and the calculation model of wheel normal force are established on the ground to complete the ground calibration; Ground test and model correction module: Conduct simulated lunar soil wheel tunneling test, invert lunar soil mechanical parameters, correct the inversion model through standard test comparison, and establish an in-situ lunar surface exploration model; Lunar exploration site selection module: Uses the lunar rover's panoramic camera to find suitable lunar soil exploration sites; Lunar surface excavation test module: Controls the lunar rover to move to the exploration location, locks five wheels, drives a single wheel at a specified speed to excavate lunar soil, and collects telemetry parameters in real time; Lunar data acquisition module: controls the lunar rover to move away from the excavation area and takes pictures of the excavated soil pile and excavation pit through the onboard camera; Lunar surface parameter inversion module: Based on the image data, the lunar soil deposition angle is obtained, and the telemetry parameters are substituted into the inversion model established on the ground to obtain the lunar soil cohesion and complete the in-situ test of the lunar soil mechanical properties.

9. A computer device, characterized in that, The device includes a memory and one or more processors, wherein the memory stores computer code that, when executed by the one or more processors, causes the one or more processors to perform the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer code, and when the computer code is executed, the method as described in any one of claims 1 to 7 is performed.

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