Traction testing of tires for 'severe snow use' certification is performed according to ASTM F1805 in the Unites States and Canada. The ASTM standard provides guidelines for the preparation and compaction of the snow required for the testing and its evaluation using the CTI (Compliance Testing Incorporated) penetrometer. However, the CTI penetrometer provides a measure of the degree of compactness of the snow. From a computational perspective, this information in itself is not sufficient for modeling and/or validation of a snow model for virtual snow traction testing, which is important in the design stage of tires. This work attempts to compare the relative compression testing performance of three devices, namely a CTI penetrometer (rounded cone tip impactor), a standard Clegg Hammer (flat surface impactor), and an in-house developed device inspired by the Russian Snow Penetrometer (cone tip impactor). The approach used here includes a comparison of the available direct and indirect outputs of all the devices and a statistical analysis of these. The observed differences may be due to differences in the mass and drop height between the devices. The findings of this work provide a baseline for further research into the optimal mass and drop height for the evaluation of compacted snow properties. From a modeling perspective, the values generated using the Clegg impact hammer could be useful. However, it tends to underestimate the elastic modulus, when its results are compared to the laboratory technique, and to overestimate the ram resistance when compared to the in-house device. Further improvements to the in-house device may improve its ability to measure the snow properties most relevant to the modeling of snow.
{"title":"Benchmarking of Compression Testing Devices in Snow","authors":"M. Shenvi, C. Sandu, C. Untaroiu","doi":"10.56884/otsp3025","DOIUrl":"https://doi.org/10.56884/otsp3025","url":null,"abstract":"Traction testing of tires for 'severe snow use' certification is performed according to ASTM F1805 in the Unites States and Canada. The ASTM standard provides guidelines for the preparation and compaction of the snow required for the testing and its evaluation using the CTI (Compliance Testing Incorporated) penetrometer. However, the CTI penetrometer provides a measure of the degree of compactness of the snow. From a computational perspective, this information in itself is not sufficient for modeling and/or validation of a snow model for virtual snow traction testing, which is important in the design stage of tires. This work attempts to compare the relative compression testing performance of three devices, namely a CTI penetrometer (rounded cone tip impactor), a standard Clegg Hammer (flat surface impactor), and an in-house developed device inspired by the Russian Snow Penetrometer (cone tip impactor). The approach used here includes a comparison of the available direct and indirect outputs of all the devices and a statistical analysis of these. The observed differences may be due to differences in the mass and drop height between the devices. The findings of this work provide a baseline for further research into the optimal mass and drop height for the evaluation of compacted snow properties. From a modeling perspective, the values generated using the Clegg impact hammer could be useful. However, it tends to underestimate the elastic modulus, when its results are compared to the laboratory technique, and to overestimate the ram resistance when compared to the in-house device. Further improvements to the in-house device may improve its ability to measure the snow properties most relevant to the modeling of snow.","PeriodicalId":447600,"journal":{"name":"Proceedings of the 11th Asia-Pacific Regional Conference of the ISTVS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124007892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yufei Liu, Lei Jiang, C. Tian, B. Xing, Zhirui Wang, Bo Su, Tong Yan, Liang Ding, Haibo Gao
Legged robots over a rugged terrain can be accomplished by taking the environment and control constraint models into account when planning foothold and robot movements. In this paper, the foot-terrain slippage evaluation model for 3-DOF leg based on dynamics model is proposed. The authors evaluate the geometrical characteristics of each cell on the local elevation map, checks slippage state constraints and kinematic constraints. Then, we employ reinforcement learning and imitation learning to develop the relationship between the local elevation map, robot state, and robot behavior. The method can help to select the foothold considered geometrical characteristics on the elevation map and the robot state can be determined. The experiments were carried out on legged robots walking over rough terrain in both simulation and real robotic platforms. And the experimental results have demonstrated the effectiveness of the proposed method.
{"title":"Foothold Selection Considering Constraint and Slippage Evaluation for Legged Robots","authors":"Yufei Liu, Lei Jiang, C. Tian, B. Xing, Zhirui Wang, Bo Su, Tong Yan, Liang Ding, Haibo Gao","doi":"10.56884/zees3819","DOIUrl":"https://doi.org/10.56884/zees3819","url":null,"abstract":"Legged robots over a rugged terrain can be accomplished by taking the environment and control constraint models into account when planning foothold and robot movements. In this paper, the foot-terrain slippage evaluation model for 3-DOF leg based on dynamics model is proposed. The authors evaluate the geometrical characteristics of each cell on the local elevation map, checks slippage state constraints and kinematic constraints. Then, we employ reinforcement learning and imitation learning to develop the relationship between the local elevation map, robot state, and robot behavior. The method can help to select the foothold considered geometrical characteristics on the elevation map and the robot state can be determined. The experiments were carried out on legged robots walking over rough terrain in both simulation and real robotic platforms. And the experimental results have demonstrated the effectiveness of the proposed method.","PeriodicalId":447600,"journal":{"name":"Proceedings of the 11th Asia-Pacific Regional Conference of the ISTVS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125742351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Its southwest's rugged and mountainous terrain has thick soil, which causes high resistance, poor efficiency, and sometimes even the impossibility to operate agricultural equipment. Using discrete element simulation, a cutting-edge technical technique, it is possible to optimize the agricultural machinery elements that come into contact with the soil in order to reduce drag and increase efficiency. Although there are presently no precise and trustworthy discrete element modeling parameters for red clay, the physical characteristics of red clay in the hilly and mountainous regions of the southwest are unique. As a result, in this study, the soil moisture content was 12.5%1% and 18.3%1%, respectively, for the actual working environment of the soil moisture content of 10%–20% in the hilly and mountainous areas of southwest China, and the experiment's measurement of the accumulation angle was 38.54°. This subject of the study was clay. To calibrate the appropriate model's physical characteristics, use the Hertz-Mindlin with JKR contact model in the EDEM simulation software. Prior to simulating the accumulation angle of soil particles, the intrinsic physical parameter values of the red loam soil are first obtained through actual experiments. The range of soil contact mechanical parameters in the GEMM database is then used to determine the optimal value interval of the contact parameters determined by the steepest slope test. In order to determine the regression model of the soil accumulation angle, the quadratic regression rotation orthogonal combination test is used to obtain the second-order regression model of the accumulation angle and the significant parameters. The significant parameters are then optimized using the actual accumulation angle as the target. In the end, it was found that the following contact mechanics characteristics worked well together in the EDEM simulation test: JKR surface energy 8 J/m2, restitution coefficient 0,35, dynamic friction coefficient 0,13, and static friction coefficient 0,56. The relative inaccuracy determined by the actual physical test is 1.80%, and the stacking angle is 39.24°. The study's findings demonstrate that the method has a high degree of calibration accuracy and is both reasonable and useful for calibrating soil discrete element simulation parameters. The pertinent calibration parameters can serve as a technological foundation for investigating machine-soil interaction and machine-tool optimization research in southwest China's hilly and mountainous regions.
{"title":"Parameters Calibration of Red Clay Soil in Hilly Area of Southwest China for Discrete Element Simulation Based on Repose Angle Test","authors":"Le Yang, Qinghui Lai, Liangliang Zhao, Peihang Li, Zhihong Zhang, Zhaoyang Chen","doi":"10.56884/bocw9283","DOIUrl":"https://doi.org/10.56884/bocw9283","url":null,"abstract":"Its southwest's rugged and mountainous terrain has thick soil, which causes high resistance, poor efficiency, and sometimes even the impossibility to operate agricultural equipment. Using discrete element simulation, a cutting-edge technical technique, it is possible to optimize the agricultural machinery elements that come into contact with the soil in order to reduce drag and increase efficiency. Although there are presently no precise and trustworthy discrete element modeling parameters for red clay, the physical characteristics of red clay in the hilly and mountainous regions of the southwest are unique. As a result, in this study, the soil moisture content was 12.5%1% and 18.3%1%, respectively, for the actual working environment of the soil moisture content of 10%–20% in the hilly and mountainous areas of southwest China, and the experiment's measurement of the accumulation angle was 38.54°. This subject of the study was clay. To calibrate the appropriate model's physical characteristics, use the Hertz-Mindlin with JKR contact model in the EDEM simulation software. Prior to simulating the accumulation angle of soil particles, the intrinsic physical parameter values of the red loam soil are first obtained through actual experiments. The range of soil contact mechanical parameters in the GEMM database is then used to determine the optimal value interval of the contact parameters determined by the steepest slope test. In order to determine the regression model of the soil accumulation angle, the quadratic regression rotation orthogonal combination test is used to obtain the second-order regression model of the accumulation angle and the significant parameters. The significant parameters are then optimized using the actual accumulation angle as the target. In the end, it was found that the following contact mechanics characteristics worked well together in the EDEM simulation test: JKR surface energy 8 J/m2, restitution coefficient 0,35, dynamic friction coefficient 0,13, and static friction coefficient 0,56. The relative inaccuracy determined by the actual physical test is 1.80%, and the stacking angle is 39.24°. The study's findings demonstrate that the method has a high degree of calibration accuracy and is both reasonable and useful for calibrating soil discrete element simulation parameters. The pertinent calibration parameters can serve as a technological foundation for investigating machine-soil interaction and machine-tool optimization research in southwest China's hilly and mountainous regions.","PeriodicalId":447600,"journal":{"name":"Proceedings of the 11th Asia-Pacific Regional Conference of the ISTVS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125592328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
After the planetary spacecraft landed on the surface, the rovers carried on the spacecraft will be powered up and arrived to the planetary surface after complex self-testing procedures. In order to validation of these procedures, the test conditions should be built in the proving ground. The technical systems of field validation for egress process of planetary rover are shown in this paper. Firstly, the Chinese rover egress procedures are described. The typical procedures include several steps such as the unlocked the fixed mechanisms of the rover body, powered up the rover through the lander, unlocked the rover typical mechanism (mast, manipulator), communicated with the earth or relay orbiter, etc. After the rover performance were reviewed, the rover can be controlled and walked to the planetary surface. Secondly, the field validation systems are given including such as the low gravity system, the integrated testing system, the rover model with its assistant equipment, the simulated lander, etc. Thirdly, the conditions of field tests are described including the slope of terrain surface, the obstacle distribution, the position of simulated lander, etc. The test results of Chinese lunar and Martian rover were shown. Finally, the egress process of Chinese rovers on Moon and Mars are described. The technical systems of field validation wear built firstly for Chinese lunar rover Chang’e-3 Yutu and improved for Chinese Martian rover Zhurong. The technical systems work well and can be used for the development of planetary rover in the future.
{"title":"Field Validation of Egress Process for Planetary Rover","authors":"Z. Dang, Jirong Zhang, Baichao Chen","doi":"10.56884/uoud6258","DOIUrl":"https://doi.org/10.56884/uoud6258","url":null,"abstract":"After the planetary spacecraft landed on the surface, the rovers carried on the spacecraft will be powered up and arrived to the planetary surface after complex self-testing procedures. In order to validation of these procedures, the test conditions should be built in the proving ground. The technical systems of field validation for egress process of planetary rover are shown in this paper. Firstly, the Chinese rover egress procedures are described. The typical procedures include several steps such as the unlocked the fixed mechanisms of the rover body, powered up the rover through the lander, unlocked the rover typical mechanism (mast, manipulator), communicated with the earth or relay orbiter, etc. After the rover performance were reviewed, the rover can be controlled and walked to the planetary surface. Secondly, the field validation systems are given including such as the low gravity system, the integrated testing system, the rover model with its assistant equipment, the simulated lander, etc. Thirdly, the conditions of field tests are described including the slope of terrain surface, the obstacle distribution, the position of simulated lander, etc. The test results of Chinese lunar and Martian rover were shown. Finally, the egress process of Chinese rovers on Moon and Mars are described. The technical systems of field validation wear built firstly for Chinese lunar rover Chang’e-3 Yutu and improved for Chinese Martian rover Zhurong. The technical systems work well and can be used for the development of planetary rover in the future.","PeriodicalId":447600,"journal":{"name":"Proceedings of the 11th Asia-Pacific Regional Conference of the ISTVS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127439491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Penetration detection is an important way to method for in-situ scientific exploration of planets, which is used to indirectly detect the mechanical properties of the planetary subsurface soil. In this paper, four ovoid-nosed penetrators with different radius penetrating different compactness of planetary soil under different impact velocity were simulated using nonlinear finite element (FE) method through Hypermesh/Ls-dyna. A nonparametric estimation method for estimating the mechanical properties of planetary soil is presented. Three main characteristic parameters in the process of penetrator penetration were adopted in the method, including maximum acceleration am, penetration depth z, and maximum deflection angle θm. Twenty identification parameters for identifying planetary soils properties were derived based on these three characteristic parameters. The terrain consisted of simulant soil classified nonparametrically and artificially defined as three states (low, medium and high compactness) based on different harnesses, and five identification criteria (slack, ideal, partially strict, relatively strict and strict) were put forward. Four superior identification parameters were derived through the analysis of the evaluation indexes (recognition rate, accurate rate and conservative rate) under different identification criteria. and are selected as the optimal identification parameters and verified by simulation test, the accurate success rate and conservative success rate of the final estimation are 58.3% and 91.7%, respectively, which indicated that the nonparametric estimation method in this work can be used to evaluate the mechanical properties of planetary soil effectively.
{"title":"Nonparametric Terrain Estimation Based on the Interaction Simulation Between Planetary Penetrator and Soil","authors":"Xintao Yang, Han Huang, Zhixin Xiang, Qinghao Yan, Haozhe Wang, Shucai Xu","doi":"10.56884/mbem9373","DOIUrl":"https://doi.org/10.56884/mbem9373","url":null,"abstract":"Penetration detection is an important way to method for in-situ scientific exploration of planets, which is used to indirectly detect the mechanical properties of the planetary subsurface soil. In this paper, four ovoid-nosed penetrators with different radius penetrating different compactness of planetary soil under different impact velocity were simulated using nonlinear finite element (FE) method through Hypermesh/Ls-dyna. A nonparametric estimation method for estimating the mechanical properties of planetary soil is presented. Three main characteristic parameters in the process of penetrator penetration were adopted in the method, including maximum acceleration am, penetration depth z, and maximum deflection angle θm. Twenty identification parameters for identifying planetary soils properties were derived based on these three characteristic parameters. The terrain consisted of simulant soil classified nonparametrically and artificially defined as three states (low, medium and high compactness) based on different harnesses, and five identification criteria (slack, ideal, partially strict, relatively strict and strict) were put forward. Four superior identification parameters were derived through the analysis of the evaluation indexes (recognition rate, accurate rate and conservative rate) under different identification criteria. and are selected as the optimal identification parameters and verified by simulation test, the accurate success rate and conservative success rate of the final estimation are 58.3% and 91.7%, respectively, which indicated that the nonparametric estimation method in this work can be used to evaluate the mechanical properties of planetary soil effectively.","PeriodicalId":447600,"journal":{"name":"Proceedings of the 11th Asia-Pacific Regional Conference of the ISTVS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132685338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The frames of many commercial vehicles are composed of rectangular tubular steel and are a significant portion of the gross vehicle weight. The introduction of a composite frame would potentially reduce weight and increase structural properties. We compare a baseline frame section to new composite sections injected with two different types of foam: a polyurethane and aluminum foam. The objective was to increase the overall strength and stiffness, while leaving the overall weight of the frame unchanged or reduced by reducing the plate thickness of the tubular steel. Sections of rectangular tubular steel are tested individually with and without the inclusion of aluminum and closed cell polyurethane foam. The potential advantages include light weighting vehicles, increasing strength and durability, improving ride through a more ridged/stiffer un-sprung mass, and the ability to make quick structural repairs of a compromised vehicle frame. The study revealed that injecting of polyurethane foam produced increase in strength while the aluminum foam did not increase the strength.
{"title":"Composite Beam Tests with Closed Cell Polyurethane and Aluminum Foam","authors":"George Mason, Ethan Salman, S. Mujahid","doi":"10.56884/vcix2361","DOIUrl":"https://doi.org/10.56884/vcix2361","url":null,"abstract":"The frames of many commercial vehicles are composed of rectangular tubular steel and are a significant portion of the gross vehicle weight. The introduction of a composite frame would potentially reduce weight and increase structural properties. We compare a baseline frame section to new composite sections injected with two different types of foam: a polyurethane and aluminum foam. The objective was to increase the overall strength and stiffness, while leaving the overall weight of the frame unchanged or reduced by reducing the plate thickness of the tubular steel. Sections of rectangular tubular steel are tested individually with and without the inclusion of aluminum and closed cell polyurethane foam. The potential advantages include light weighting vehicles, increasing strength and durability, improving ride through a more ridged/stiffer un-sprung mass, and the ability to make quick structural repairs of a compromised vehicle frame. The study revealed that injecting of polyurethane foam produced increase in strength while the aluminum foam did not increase the strength.","PeriodicalId":447600,"journal":{"name":"Proceedings of the 11th Asia-Pacific Regional Conference of the ISTVS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132880665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sliding plate was the key soil-engaging component of rice direct seeding and planting machinery. It has the problems of large sliding resistance and serious soil adhesion. which has a serious negative impact on the operation efficiency and quality of rice planting machinery. Reducing the soil adhesion and resistance between sliding plate and soil can significantly improve the operation effect of the whole machine and reduce power consumption. Loach moves freely and flexibly in the mud and has highly efficient lubrication and drag reduction effects. The movement state of sliding plate was similar to that of loach, as well as the working environment and conditions. Therefore, the sliding plate of rice direct seeding machine was selected as the research object and the loach as the bionic prototype. The macroscopic and microscopic structure characteristics of the scales were observed, the results showed that the body surface of the loach was covered by scales, and the scales had a ridged non-smooth structure. The simulation analysis of the drag reduction performance of the non-smooth structure based on Fluent was carried out, the results show that the maximum drag reduction rate was 2.55% at the speed of 1m/s. The bionic sliding plate of rice direct-seeding machine was constructed based on the non-smooth structure of loach body surface, and its working performance was simulated and analyzed. The single factor test results show that at the speed of 1m/s, the drag reduction rate of ribbed height in the range of 3.5mm to 4.5mm was relatively high, the drag reduction rate of ribbed width in the range of 4mm-5mm was relatively high; the drag reduction rate was relatively high when the distance between ribs was in the range of 4mm5mm. The results of orthogonal test show that the order of primary and secondary factors of bionic structure parameters affecting drag reduction rate was ribbed spacing > ribbed width > ribbed height. The optimal parameter combination was ribbing height 4mm, ribbing width 4.5mm, ribbing spacing, and the optimal drag reduction rate was 4.21%. The results of this study can provide theoretical support for bionic design of soil engaging components of rice planting machinery in wet and soft paddy field.
{"title":"Research on Drag Reduction Performance of Sliding Plate of Rice Direct Seeding Machine Based on Non Smooth Structure of Loach Surface","authors":"Hongchang Wang, Zhenghua Jiang, Kaiquan Ding, Guozhong Zhang, A. Salem, Yuan Gao","doi":"10.56884/kual5071","DOIUrl":"https://doi.org/10.56884/kual5071","url":null,"abstract":"Sliding plate was the key soil-engaging component of rice direct seeding and planting machinery. It has the problems of large sliding resistance and serious soil adhesion. which has a serious negative impact on the operation efficiency and quality of rice planting machinery. Reducing the soil adhesion and resistance between sliding plate and soil can significantly improve the operation effect of the whole machine and reduce power consumption. Loach moves freely and flexibly in the mud and has highly efficient lubrication and drag reduction effects. The movement state of sliding plate was similar to that of loach, as well as the working environment and conditions. Therefore, the sliding plate of rice direct seeding machine was selected as the research object and the loach as the bionic prototype. The macroscopic and microscopic structure characteristics of the scales were observed, the results showed that the body surface of the loach was covered by scales, and the scales had a ridged non-smooth structure. The simulation analysis of the drag reduction performance of the non-smooth structure based on Fluent was carried out, the results show that the maximum drag reduction rate was 2.55% at the speed of 1m/s. The bionic sliding plate of rice direct-seeding machine was constructed based on the non-smooth structure of loach body surface, and its working performance was simulated and analyzed. The single factor test results show that at the speed of 1m/s, the drag reduction rate of ribbed height in the range of 3.5mm to 4.5mm was relatively high, the drag reduction rate of ribbed width in the range of 4mm-5mm was relatively high; the drag reduction rate was relatively high when the distance between ribs was in the range of 4mm5mm. The results of orthogonal test show that the order of primary and secondary factors of bionic structure parameters affecting drag reduction rate was ribbed spacing > ribbed width > ribbed height. The optimal parameter combination was ribbing height 4mm, ribbing width 4.5mm, ribbing spacing, and the optimal drag reduction rate was 4.21%. The results of this study can provide theoretical support for bionic design of soil engaging components of rice planting machinery in wet and soft paddy field.","PeriodicalId":447600,"journal":{"name":"Proceedings of the 11th Asia-Pacific Regional Conference of the ISTVS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132709474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuto Ishii, Isami Suto, Hiroaki Tabe, K. Nagato, Moju Zhao, Yoshifumi Ueshige, Takashi Iritani, M. Nakao
The development of rotary claws in tiller machines has been evaluated using actual equipment and analysis based on the discrete element method (DEM), which is an effective method for modeling the movement of granular materials. The required functions of the rotary claw are to break the soil into small pieces and plow the soil flat. However, evaluation by testing using actual equipment is difficult for precise measurements, and a considerable amount of time is required for one test. Additionally, DEM simulations have difficulty reproducing the soil behavior owing to the large number of parameters that determine their accuracy. Therefore, a comparison with the experimental results is necessary when determining DEM parameters. This research aims to develop a soil clod recognition method and an evaluation system for evaluating tractor performance. The evaluation system was designed to measure the soil shape before and after tilling with a 1/4-scale tillage claw. To capture the changes in the soil shape and distribution and size of the soil clods, we developed an image processing method. This method uses pointcloud data obtained from a depth camera to calculate the difference before and after tilling. The experimental parameters were the soil moisture content and claw rotation speed. Their effects on the formation and decomposition of the soil clods were evaluated. To confirm the feasibility of the results obtained from the proposed evaluation system, DEM simulations were performed under identical conditions to compare the distribution and size of the soil clods and changes in soil shape. The experimental results showed that the location, number, and size of scattered soil clods varied with the moisture content of the soil, and rotational speed of the claw. Based on the experimental results, a comparison was made with the results of the DEM analysis to clarify the differences between the two. The developed model experiment system for soil clods and the image processing method made it possible to quantitatively compare soil dispersal between the experiment and the DEM, which may accelerate the search for parameters for the DEM to reproduce the tilling.
{"title":"Construction of a Soil Clods Recognition Bench-Scale Experiment for Discrete Element Method Modeling of Tilling Phenomena","authors":"Shuto Ishii, Isami Suto, Hiroaki Tabe, K. Nagato, Moju Zhao, Yoshifumi Ueshige, Takashi Iritani, M. Nakao","doi":"10.56884/vbxy3767","DOIUrl":"https://doi.org/10.56884/vbxy3767","url":null,"abstract":"The development of rotary claws in tiller machines has been evaluated using actual equipment and analysis based on the discrete element method (DEM), which is an effective method for modeling the movement of granular materials. The required functions of the rotary claw are to break the soil into small pieces and plow the soil flat. However, evaluation by testing using actual equipment is difficult for precise measurements, and a considerable amount of time is required for one test. Additionally, DEM simulations have difficulty reproducing the soil behavior owing to the large number of parameters that determine their accuracy. Therefore, a comparison with the experimental results is necessary when determining DEM parameters. This research aims to develop a soil clod recognition method and an evaluation system for evaluating tractor performance. The evaluation system was designed to measure the soil shape before and after tilling with a 1/4-scale tillage claw. To capture the changes in the soil shape and distribution and size of the soil clods, we developed an image processing method. This method uses pointcloud data obtained from a depth camera to calculate the difference before and after tilling. The experimental parameters were the soil moisture content and claw rotation speed. Their effects on the formation and decomposition of the soil clods were evaluated. To confirm the feasibility of the results obtained from the proposed evaluation system, DEM simulations were performed under identical conditions to compare the distribution and size of the soil clods and changes in soil shape. The experimental results showed that the location, number, and size of scattered soil clods varied with the moisture content of the soil, and rotational speed of the claw. Based on the experimental results, a comparison was made with the results of the DEM analysis to clarify the differences between the two. The developed model experiment system for soil clods and the image processing method made it possible to quantitatively compare soil dispersal between the experiment and the DEM, which may accelerate the search for parameters for the DEM to reproduce the tilling.","PeriodicalId":447600,"journal":{"name":"Proceedings of the 11th Asia-Pacific Regional Conference of the ISTVS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116267983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rubber tracked running gears are widely used in high-mobility Unmanned Ground Vehicles (UGV) to increase obstacle negotiation possibility in urban and rural terrain. The paper proposes a method of assessing the configuration of the light UGV`s tracked running gear in terms of the ability to overcome terrain obstacles. Five types of obstacles have been proposed: a road ditch, a lying log, a curb, a crop rows and a wavy meadow profile. Then designed four types of running gear with the same geometrical and mass parameters, differing in the way of applying the running wheels (rigid construction, consisted of sprocket, idler and four road wheels, two bogies solution, system with two bogies elastically mounted to frame and rocker-bogie construction). To compare the selected solutions, simulation in the multi-body environment program and the equations based on the Bekker theory was performed. The simulation results showed an improvement in the driving properties with the use of elastically suspended elements. Better copying of the shape of the obstacle by the running gear contributes to the required tractive effort at lower slip values. At the same time, the negative impact of elastically suspended elements on the platform's stability was indicated.
{"title":"The Running Gear Construction Impact on Obstacles Overcoming by Light High-Mobility UGV","authors":"Daniela Szpaczyńska, M. Łopatka, P. Krogul","doi":"10.56884/qsjo7805","DOIUrl":"https://doi.org/10.56884/qsjo7805","url":null,"abstract":"Rubber tracked running gears are widely used in high-mobility Unmanned Ground Vehicles (UGV) to increase obstacle negotiation possibility in urban and rural terrain. The paper proposes a method of assessing the configuration of the light UGV`s tracked running gear in terms of the ability to overcome terrain obstacles. Five types of obstacles have been proposed: a road ditch, a lying log, a curb, a crop rows and a wavy meadow profile. Then designed four types of running gear with the same geometrical and mass parameters, differing in the way of applying the running wheels (rigid construction, consisted of sprocket, idler and four road wheels, two bogies solution, system with two bogies elastically mounted to frame and rocker-bogie construction). To compare the selected solutions, simulation in the multi-body environment program and the equations based on the Bekker theory was performed. The simulation results showed an improvement in the driving properties with the use of elastically suspended elements. Better copying of the shape of the obstacle by the running gear contributes to the required tractive effort at lower slip values. At the same time, the negative impact of elastically suspended elements on the platform's stability was indicated.","PeriodicalId":447600,"journal":{"name":"Proceedings of the 11th Asia-Pacific Regional Conference of the ISTVS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123829774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jincheng Diao, Jingwei Gao, Xiaobo Song, Baojun Di
Soil shear strength is an important index of soil mechanical properties, which is of great significance in fields such as rock and soil stress analysis, agricultural machinery farming, seabed exploration, and vehicle trafficability evaluation. In order to improve the problems existing in the existing methods of obtaining soil shear strength index, such as low accuracy, demanding experimental site conditions and long periodicity, this paper constructed a model of free-fall cone penetration into the soil based on the discrete element method (DEM) simulation, and the corresponding relationship between moisture content and penetration depth was obtained. In addition, the corresponding relationship between the moisture content and the soil shear strength index was obtained from the triaxial compression test. Combining these two relational equations, this paper finally summarized the equation about the relationship between the penetration depth in the simulation and the soil shear strength index in the test. It was verified that the errors of internal friction angle (φ) and internal cohesion (c) obtained by the equation were only 3.45% and 6.68%. It shows that the DEM free-fall cone penetration simulation can replace the triaxial compression test to obtain soil shear strength index with very low error, and it is a quick and accurate new method to acquire the soil mechanical parameters.
{"title":"A Method for Fast Obtaining of Soil Shear Strength Index Based on Dem Free-Fall Cone Penetration Simulation","authors":"Jincheng Diao, Jingwei Gao, Xiaobo Song, Baojun Di","doi":"10.56884/pfqd4535","DOIUrl":"https://doi.org/10.56884/pfqd4535","url":null,"abstract":"Soil shear strength is an important index of soil mechanical properties, which is of great significance in fields such as rock and soil stress analysis, agricultural machinery farming, seabed exploration, and vehicle trafficability evaluation. In order to improve the problems existing in the existing methods of obtaining soil shear strength index, such as low accuracy, demanding experimental site conditions and long periodicity, this paper constructed a model of free-fall cone penetration into the soil based on the discrete element method (DEM) simulation, and the corresponding relationship between moisture content and penetration depth was obtained. In addition, the corresponding relationship between the moisture content and the soil shear strength index was obtained from the triaxial compression test. Combining these two relational equations, this paper finally summarized the equation about the relationship between the penetration depth in the simulation and the soil shear strength index in the test. It was verified that the errors of internal friction angle (φ) and internal cohesion (c) obtained by the equation were only 3.45% and 6.68%. It shows that the DEM free-fall cone penetration simulation can replace the triaxial compression test to obtain soil shear strength index with very low error, and it is a quick and accurate new method to acquire the soil mechanical parameters.","PeriodicalId":447600,"journal":{"name":"Proceedings of the 11th Asia-Pacific Regional Conference of the ISTVS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125209816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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