Journal of Terramechanics最新文献

The use of intensive technologies for the cultivation of agricultural crops provides for the application of fertilizers in the process of tillage. This reduces the compaction of the soil, increases its fertility and the quality of the crop. The purpose of these studies is to develop a universal working tool that allows you to combine several technological operations in one pass of the unit. The authors have developed an original design of a plow-subsoiler-fertilizer. This combined working body includes a reversible plow and a vibratory subsoiler with fertilizer ducts. This solution allows you to combine the application of fertilizers when plowing the field, loosening the subsoil layer and mixing the soil. As a result of the work, the dependences of the geometric dimensions of the structure on the traction resistance to movement in the soil were obtained. To implement the developed idea into a real design, the main parameters of the plow-subsoiler-fertilizer are determined. Particular attention is paid to the calculation of the spring mechanism that ensures the vibration of the subsoiler. The optimal number and location of belleville springs in the block and shock absorber were selected, at which the subsoiler will perform self-oscillations with a given amplitude.

A novel evaluation method for rolling energy losses of road wheels of tracked vehicle is proposed, in which damping of road wheel surface is identified based on single vibration excitation and single point picking up frequency response function using a simplified modal experiment with an acceleration sensor. Three road wheels of tracked vehicle with different tread rubber are utilized as specimens during the modal experiments. The half power bandwidth method is employed to identify the viscous damping parameters. The damping parameters of road wheels are ranked by their values, and then these values of every road wheels are compared with their corresponding rolling energy losses to validate their correlative relationship. Moreover, the nonlinear deformation and stiffness of road wheels are investigated about their correlation with the rolling energy losses through model development and experimental validation. The results prove that the damping ratios of road wheels are correlated well with the rolling energy losses for all the three road wheels. The proposed evaluation method could effectively evaluate the rolling energy losses of road wheels, which suggests a simplified and economical alternative over the conventional rolling energy losses experimental method of road wheels.

Vehicle terrain mobility characteristics, provided by the powertrain and running gear, are realized in dynamic interactions between the wheels and terrain. Approaches to modeling and simulation of vehicle-terrain interaction and mobility characteristics as well as engineering approaches to design powertrain sub-systems together pre-determine a vehicle’s technical success or failure before it touches the ground. This article develops a vehicle mobility design technique, applicable to both manned and unmanned platforms, concerned with powertrain power conversion and realization in tire-terrain interactions. The modeling component is based on multi-drive-wheel vehicle longitudinal dynamics combined with terramechanics and powertrain characteristics. The approach advances the conventional dynamic factor by introducing the conjoint effect of the engine, transmission, and driveline system on vehicle traction and acceleration performance in terrain conditions where circumferential wheel forces and tire slippages may differ from each other. The vehicle design component of the proposed technique introduces drivetrain, driveline, and powertrain design factors that assess the influence of the drivetrain and driveline systems on traction, acceleration performance, power conversion, and realization at the wheels. The vehicle-design-for-mobility technique is completed by examining indices of mobility margins and performance. An analysis of several 8x8 armored personal carriers and 4x4 off-road vehicles illustrates the proposed technique.

Due to the long-term weathering and erosion climate, many craters terrains on the surface of Mars are covered with loose weathered sedimentary debris, and Mars rovers traversing these slope-like terrains with soft soils will easily slip or even sink, and may affect the survey missions. Therefore, it is important to study the climbing ability of Mars rovers for Mars exploration missions. This work testes the climbing capability of 'Zhurong' Mars rover based on active–passive suspensions under the simulated Martian terrain and soil parameters were adequately measured. The maximum climbing distance (MCD), slip rate, power, current, energy, and efficiency are analyzed to explore the climbing abilities under different climbing methods, soil states and dynamic parameters (speeds, angular velocity) settings. The test results show that the peristaltic mode is able to continue climbing after a direct climb failure, and the MCD per period is influenced by angular velocity. The power and current data can effectively reflect the difficulty of the rover climbing. Under the same dynamic parameters, the greater the slip rate of the rover, the larger the output power and current. In addition, the speed should be minimized to prolong the climbing distance, no matter it is direct or peristaltic climbing.

This study proposes a quick and reliable method for estimating the soil thrust in clay ground for a tracked vehicle based on limit analysis in three-dimensional conditions. With respect to the shape and location of failure surfaces in clayey ground, block, triangular wedge, and trapezoidal wedge failure modes were considered. Between the upper-bound solutions from the different failure modes, the least upper-bound solution was proposed as the soil thrust. To verify the proposed solution, it was compared to the model test and numerical simulations for a track system over model clay ground. The proposed upper-bound solution is expected to produce a reliable soil thrust quickly in real time, especially for submerged heavy-weight remotely operated vehicles (ROVs).

Obstacle detection is a complex task involving detection of obstacle features, identification of appropriate sensor and environmental conditions. The development of water hazard detection in the past two decades can be regarded as a microcosm of the history of typical obstacle detection. This review provides an extensive study of water hazard detection papers spanning a quarter-century (the 1990 s to 2021). The review mainly focuses on the width of water hazards, features of water hazards, sensor types for the detection of water hazards, and environmental light. This paper analyses and summarizes the research overview and status of some research institutions in the field over the past 20 years, hoping to provide some reference for UGV water hazard detection. In addition, the existing water hazard detection problems are summarized, and future development trends are proposed.

This paper provides a review of path tracking strategies used in autonomous vehicle control design. Several elements of modelling process and path tracking control are examined, including the vehicle model implemented, the path tracking control algorithms used, and the criteria for evaluating the controller's performance. Path tracking control is classified into several forms based on its methodology and linearity. Vehicle models are grouped into numerous types based on the linearity and the intended behaviour to be observed. This study explores each of these strategy in terms of the applicability and disadvantages/advantages. The main challenges in the field of path tracking control are defined and future research directions are offered based on the critical reviews. Based on the entire review, a model-based controller based on a linear vehicle model and assessed with hardware-in-the-loop (HIL) is suggested. This review is aimed to serve as a starting point for determining which controllers to use in path tracking control development for an autonomous tracked vehicle.

Snow traction is a key performance characteristic for tire design. Designing snow tires requires extensive testing on snow-covered proving grounds. Thus, numerical simulation could be a more efficient and less costly method of improving tire designs. Various numerical approaches, such as analytical methods, grid-based methods, and particle-based methods were employed for compacted snow modeling in literature. Analytical models of compacted snow were developed based on various assumptions about snow mechanics and tire-snow interaction. With increasing the computational power, grid-based methods (especially Arbitrary Lagrangian Eulerian method) showed to provide effective modeling of complex tire-snow interaction behavior. However, these approaches showed some limitations in modelling large and discontinuous deformation problems associated with tire-snow interaction. Therefore, recently, the use of particle-based methods, which overcome these limitations, has recently sparked interest in tire-snow modeling. The numerical studies related to the modeling tire-snow interaction are briefly reviewed in this paper. Furthermore, various constitutive snow material models and different failure theories used in literature, which are essential for numerical tire-compacted snow simulations, are also reviewed. Overall, this review paper could be useful for researchers interested in modeling the tire – snow interactions and even tire-deformable soil interaction.