Charles Noren, Bhaskar Vundurthy, Sebastian Scherer, Matthew Travers
{"title":"Interaction-aware control for robotic vegetation override in off-road environments","authors":"Charles Noren, Bhaskar Vundurthy, Sebastian Scherer, Matthew Travers","doi":"10.1016/j.jterra.2024.101034","DOIUrl":"10.1016/j.jterra.2024.101034","url":null,"abstract":"<div><div>Robotic systems tasked with completing off-road economic, military, or humanitarian missions often encounter environmental objects when traversing unstructured terrains. Certain objects (e.g. safety cones) must be avoided to ensure operational integrity, but others (e.g. small vegetation) can be interacted with (e.g. overridden/pushed) safely. Pure object-avoidance assumptions in conventional robotic system navigation policies may lead to inefficient (slow) or overly-cautious (immobilized) traversal behaviors in off-road terrains. To address this gap in system performance, we draw inspiration from existing hybrid dynamic system control literature. We have designed a nonlinear trajectory optimization controller that utilizes vegetation-interaction models as a jump map in the dynamics constraint. In contrast to purely vision-based navigation policies which classify the traversability of obstacles, the allowable subset of objects with which the vehicle can safely interact is now characterized by a data-driven collision model and the existence of a dynamically-feasible trajectory which satisfies the contact constraints. The controller’s capabilities are demonstrated on a full-sized autonomous utility task vehicle where objects including posts and trees of up to 25.4 [mm] and 81.8 [mm] diameter are overridden.</div></div>","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":"117 ","pages":"Article 101034"},"PeriodicalIF":2.4,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Analyzing bearing capacity changes due to vibration in discrete element method simulations","authors":"Tomohiro Watanabe , Ryoma Higashiyama , Dai Watanabe , Kojiro Iizuka","doi":"10.1016/j.jterra.2024.101031","DOIUrl":"10.1016/j.jterra.2024.101031","url":null,"abstract":"<div><div>Recently, legged robots have gained significant attention as highly mobile platforms for planetary exploration. However, the surfaces of celestial bodies such as the Moon are mainly composed of loose materials, leading to slippage due to the deformation of the surface under the movements of the rover’s legs. To address this issue, we proposed a walking method designed to minimize slippage. Our previous research demonstrated that applying vibrations can increase both the shear strength of the ground and the amount of the rover’s leg subsidence, thereby enhancing the ground’s bearing capacity, which is related to the counterforce provided by the ground against the legs of the rover. For the robot to perform optimally, it is essential to accurately estimate this bearing capacity to select efficient vibration settings. In this study, we utilized the discrete element method (DEM) to simulate the ground’s bearing capacity under various vibrational influences changing both the sinkage depth of a leg and the vibration frequency. Our simulations successfully mirrored the real-world effects of vibrations on bearing capacity, providing insightful perspectives on how vibration can be used to enhance ground support for these robotic explorers.</div></div>","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":"118 ","pages":"Article 101031"},"PeriodicalIF":2.4,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adewale M. Sedara , Mohamed A.A. Abdeldayem , Francisco Pratas Glycerio de Freitas , Tekeste Z. Mehari
{"title":"Optimization of subsoiler design using similitude-based DEM simulation and soil bin testing on cohesive-frictional artificial soil","authors":"Adewale M. Sedara , Mohamed A.A. Abdeldayem , Francisco Pratas Glycerio de Freitas , Tekeste Z. Mehari","doi":"10.1016/j.jterra.2024.101026","DOIUrl":"10.1016/j.jterra.2024.101026","url":null,"abstract":"<div><div>The study highlights the need for effective and efficient methods in designing tillage shanks to alleviate deep soil compaction, especially in wet soil conditions. Current techniques relying on full-scale tillage tools testing are prone to costly and time-consuming engineering product development cycles. DEM simulation of soil-to-shank interaction was utilized for screening twelve geometrically scaled (1:5.63) shanks to top-ranked six shanks, aiming reduced soil horizontal forces and maximum bulk density difference. Six scaled shanks (a straight, a bent, and four paraplow shapes) were fabricated and tested using a split-plot design soil bin experiment on cohesive-frictional artificial soil to investigate their performances on soil reaction forces and soil loosening parameters. Shank design had significant effects (<em>p</em> < 0.05) on energy responses (soil horizontal and vertical reaction forces), above-ground soil loosening (cross-sectional area, trench width, bulk density difference), and below-ground soil loosening (soil rupture area, D1 and D2) parameters. Using an optimization profiler, S-3 (β = 60°, α = 45°) demonstrated the best overall desirability score (0.58) with objectives reducing soil reaction forces and maximizing soil loosening. Manufacturing the S-3 to a full scale is proposed for evaluating its efficiency in tillage energy and soil loosening on field soil conditions for subsoil compaction management.</div></div>","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":"117 ","pages":"Article 101026"},"PeriodicalIF":2.4,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Lallemand , C. De Sousa , C. Hermange , J. Michel , G. Oger
{"title":"A Riemann-based SPH formulation for modelling elastoplastic soil behaviour using a Drucker–Prager model","authors":"M. Lallemand , C. De Sousa , C. Hermange , J. Michel , G. Oger","doi":"10.1016/j.jterra.2024.101033","DOIUrl":"10.1016/j.jterra.2024.101033","url":null,"abstract":"<div><div>The present paper aims at proposing and investigating a Riemann-based SPH formulation to simulate the elastoplastic behaviour of soils undergoing large deformations, using a Drucker–Prager model. Basing on the pioneer work from Parshikov and Medin (Parshikov and Medin, 2002), a Riemann solver is used to maintain regular fields while being free of tuning parameters. By contrast to the work in Parshikov and Medin (2002) where piecewise constant reconstructions were employed, piecewise linear reconstructions are preferred in this work to reduce the numerical diffusion. A Particle Shifting Technique (PST) is used to maintain regular particle distributions and consequently accurate SPH interpolations. To the best of the author’s knowledge, the use of a Riemann solver specific to solid mechanics with a pressure-dependent elastoplastic Drucker–Prager yield surface to model the behaviour of the material represents a novelty with respect to the existing literature. A Boundary Integral Method (BIM) initially derived for fluid dynamics (Ferrand et al., 2013; Chiron et al., 2019) is adapted to solid mechanics in order to handle complex geometries. It allows to deal with wall treatment without using fictitious particles, and shows satisfactory results even in sharp angle regions. The ability of the proposed Riemann-based formulation to simulate accurately elastoplastic problems and its robustness are examined through several test cases in plane strain conditions. Attention is paid to the capacity of the formulation to mitigate the occurrence of Tensile Instability (TI) with respect to other schemes, for which additional treatment is required to treat this issue, such as the additional artificial stress method (Gray et al., 2001).</div></div>","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":"117 ","pages":"Article 101033"},"PeriodicalIF":2.4,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mehari Tekeste Guest editor, Thomas R. Way Guest editor, Mustafa Alsaleh Guest editor
{"title":"Editorial: Soil modeling and simulation for terramechanics applications of manned and unmanned autonomous vehicles","authors":"Mehari Tekeste Guest editor, Thomas R. Way Guest editor, Mustafa Alsaleh Guest editor","doi":"10.1016/j.jterra.2024.101032","DOIUrl":"10.1016/j.jterra.2024.101032","url":null,"abstract":"","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":"117 ","pages":"Article 101032"},"PeriodicalIF":2.4,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Acoustic winter terrain classification for offroad autonomous vehicles","authors":"Anthony T. Fragoso","doi":"10.1016/j.jterra.2024.101028","DOIUrl":"10.1016/j.jterra.2024.101028","url":null,"abstract":"<div><div>Autonomous vehicles can experience extreme changes in performance when operating over winter surfaces, and require accurate classification to transit them safely. In this work we consider acoustic classification of winter terrain, and demonstrate that a simple and efficient frequency-space analysis exposed to a small convolutional neural network, rather than recurrent architectures or temporally-varying spectrogram inputs, is sufficient to provide near-perfect classification of deep snow, hardpacked surfaces and ice. Using a dual-microphone configuration, we also show that acoustic classification performance is due to a combination of vehicle noises and vehicle-terrain interaction noises, and that engine sounds can serve as a particularly powerful classification cue for offroad environments.</div></div>","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":"117 ","pages":"Article 101028"},"PeriodicalIF":2.4,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142650960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Investigation of steer preview methods to improve predictive control methods on off-road vehicles with realistic actuator delays","authors":"Andries J. Peenze, P. Schalk Els","doi":"10.1016/j.jterra.2024.101027","DOIUrl":"10.1016/j.jterra.2024.101027","url":null,"abstract":"<div><div>This paper investigates improvements that can be made to predictive control methods for off-road vehicles by adding of realistic steering preview. The objective of this study is to improve the performance and efficacy of predictive controllers by accounting for significant time delays in active and semi-active systems on vehicles. Traditional zero-order and first-order hold methods for steer preview are compared to a more realistic steer preview method. Semi-active suspension, rear wheel steering, and individual brake actuation are used as the actuators on this off-road vehicle. The results show that the addition of a realistic steering preview improves the handling performance of the vehicle in a severe double lane change manoeuvre on rough roads. Up to 10% reduction in roll angle can be achieved with semi-active suspension control. A 34% reduction in side-slip angle is possible with rear wheel steering control and a 15% reduction in side-slip angle is achieved with differential braking control. The controllers can pre-empt and consider the effect of the actuator time delays, and the preview states from the predictive controller are more representative over the prediction horizon. The findings suggest that the addition of a realistic steering preview can improve the performance of predictive controllers on vehicles. Further investigation of other disturbances and their preview effects on the system should be conducted to find further improvements for predictive control strategies on vehicles.</div></div>","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":"117 ","pages":"Article 101027"},"PeriodicalIF":2.4,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142650957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comparison of selected tire-terrain interaction models from the aspect of accuracy and computational intensity","authors":"Dávid Körmöczi , Péter Kiss","doi":"10.1016/j.jterra.2024.101030","DOIUrl":"10.1016/j.jterra.2024.101030","url":null,"abstract":"<div><div>Accurate modeling or simulation of the vehicle-terrain interaction is critical for effective off-road vehicle navigation. While several high-accuracy methods exist (for example FEM simulation) they typically require computational capacity that exceeds what can be installed in a vehicle. Therefore, they are not applicable for real-time off-road vehicle navigation purposes, where computer hardware capacity is limited by the need for onboard installation. To address this challenge, simplified and less detailed models must be developed for real-time applications. This paper compares three different two-dimensional static terrain-vehicle models, considering accuracy and computational capacity requirements. Results of the comparison provide insights into the suitability of each model for real-time navigation of off-road vehicles.</div></div>","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":"117 ","pages":"Article 101030"},"PeriodicalIF":2.4,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142650959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Simulation of cohesive-frictional artificial soil-to-blade interactions using an elasto-plastic discrete element model with stress-dependent cohesion","authors":"Mohamed A.A. Abdeldayem , Mehari Z. Tekeste","doi":"10.1016/j.jterra.2024.101029","DOIUrl":"10.1016/j.jterra.2024.101029","url":null,"abstract":"<div><div>The discrete element method (DEM) has become a valuable computational technique for simulating soil dynamic loading during bulldozer cutting processes. It allows for the virtual design of Ground Engaging Tools (GETs) and predicting energy expenditure during earthmoving operations. Few studies exist for modeling dynamic soil-cutting processes of soils exhibiting elasto-plastic behavior with stress-history-dependent cohesive soil behavior. The study aimed to calibrate an elasto-plastic DEM soil model, with cohesion, for a cohesive-frictional artificial soil and predict soil reaction forces from soil-to-blade interaction. Plackett-Burman screening design of experiment (DOE) and inverse profiling techniques were applied to calibrate the elasto-plastic DEM soil model, with cohesion, predicting soil compaction energy with a percent relative error (PRE) of 3 % and maximum normal stress (PRE of 1 %) using cohesive-frictional artificial soil in a uniaxial confined compression test. Validation of the calibrated DEM soil model resulted in good prediction of soil reaction forces versus blade displacement for a narrow planar blade, a wide planer blade, and a geometrically scaled curved bulldozer blade, with RMSE values of 2.04 N, 14.89 N, and 7.42 N, respectively. The findings showed that elasto-plastic soil behavior with stress-dependent cohesion can be modeled using DEM for simulating the cutting and moving of earthen materials, offering valuable insights for optimizing GET design and development of digital twins of earthmoving operations.</div></div>","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":"117 ","pages":"Article 101029"},"PeriodicalIF":2.4,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David Gorsich , Vladimir Vantsevich , Jesse Paldan , Lee Moradi
{"title":"Modelling and simulation fundamentals in design for ground vehicle mobility Part II: Western approach","authors":"David Gorsich , Vladimir Vantsevich , Jesse Paldan , Lee Moradi","doi":"10.1016/j.jterra.2024.101023","DOIUrl":"10.1016/j.jterra.2024.101023","url":null,"abstract":"<div><div>For many decades, different approaches, fundamentals, and expressions have been developed in various countries for military vehicle modelling and simulation (M&S) as a core component of ground vehicle design for mobility. The political division of the world into the West and East that existed before the Soviet Union breakdown in 1991 had not facilitated collaboration between researchers and engineers of both sides, and, thus, they created and practiced their own approaches. The war in Ukraine urgently prompted analysis of the origins and essence of the Western and Eastern technical paradigms, which being conceptually different to ground vehicle mobility, had predetermined the development of vehicle M&S methods and techniques in their parts of the world, specifically for studying dynamic interactions of vehicles with severely uncertain terrains, which impact vehicle behavior and performance, and, thus, may either facilitate mission accomplishment or lead to its failure. Furthermore, this analysis of the technical paradigms aims to further advance M&S fundamentals for next generation combat vehicles as described in the U.S. Army’s 2019 Modernization Strategy. Part I of this article considers the Eastern approach and the Western approach is presented in Part II.</div></div>","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":"117 ","pages":"Article 101023"},"PeriodicalIF":2.4,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}