Modelling and control strategies in path tracking control for autonomous tracked vehicles: A review of state of the art and challenges

Kadir, Saiddi Ali Firdaus Mohamed Ishak, Syed Mohd Fairuz Syed Dardin

Journal of Terramechanics, Volume 105, 2023, Pages 67-79, ISSN 0022-4898

https://doi.org/10.1016/j.jterra.2022.10.003.(https://www.sciencedirect.com/science/article/pii/S0022489822000714)

Abstract: 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.

Keywords: Path tracking; Autonomous tracked vehicle; Steering control; Trajectory following

Water hazard detection: A 20-year review

Xiaodong Guo, Jizhou Han, Jingyu Li, Zhoubo Wang, Zhenhai Zhang, Xiao Kang, Wei Zhu, Hongbin Deng

Journal of Terramechanics, Volume 105, 2023, Pages 53-66, ISSN 0022-4898

https://doi.org/10.1016/j.jterra.2022.11.002.(https://www.sciencedirect.com/science/article/pii/S002248982200074X)

Abstract: 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.

Keywords: Water hazards; UGV; Obstacle detection; Multisensor fusion; Classification

Upper-bound solutions for the soil thrust of clay under a track system in 3D conditions

Sang Inn Woo, Sung-Ha Beak

Journal of Terramechanics, Volume 105, 2023, Pages 41-51, ISSN 0022-4898

https://doi.org/10.1016/j.jterra.2022.11.001.(https://www.sciencedirect.com/science/article/pii/S0022489822000738)

Abstract: 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).

Keywords: Remotely operated vehicle; Soil thrust; Clay; Upper bound; Plasticity

Review of modeling methods of compressed snow-tire interaction

Yogesh Surkutwar, Corina Sandu, Costin Untaroiu

Journal of Terramechanics, Volume 105, 2023, Pages 27-40, ISSN 0022-4898

https://doi.org/10.1016/j.jterra.2022.10.004.(https://www.sciencedirect.com/science/article/pii/S0022489822000726)

Abstract: 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.

Keywords: Compacted snow; Snow material models; Snow material properties; Finite Element Method (FEM); Arbitrary Lagrangian Eulerian (ALE) method; Smoothed Particle Hydrodynamics (SPH) method; Discrete Element Method (DEM)

Parametric analysis of traction energy of an autonomous wheeled robotic system for application in greenhouse environment

S.M. Shafaei, H. Mousazadeh

Journal of Terramechanics, Volume 105, 2023, Pages 11-25, ISSN 0022-4898

https://doi.org/10.1016/j.jterra.2022.10.002.(https://www.sciencedirect.com/science/article/pii/S0022489822000702)

Abstract: The novel purpose of this applied research is to gain insight into traction energy aspect of an autonomous wheeled robotic system for carrying, spraying, and harvesting tasks in the greenhouse environment. Traction energy indicators (traction energy consumption, traction energy dissipation, and drawbar pull energy) of a wheeled robot were ascertained as affected by operational variables of robot forward speed (0.17, 0.33 and 0.5 m/s), payload weight (1, 2, 3, 4 and 5 kN) and tire air pressure (20.68, 34.47 and 55.16 kPa). Analytical results clarified that meaningful contribution of robot forward speed to the traction energy indicators was marginal (<40 times) in comparison with that of payload weight. This indicated that adjustment of payload weight should be considered as first priority for performance optimization of the robotic system. Meanwhile, modeling results described that the combinatorial effect of payload weight and robot forward speed on traction energy indicators was synergetic. This disclosed linear increasing dependency of traction energy consumption (145–19-873.41 J/m2), traction energy dissipation (9.01–292.85 J/m2), and drawbar pull energy (140.17–864.85 J/m2) on concurrent increment of payload weight and robot forward speed. The aforementioned amplitudes divulge that 5.77–33.78 % of traction energy consumption was dissipated by wheels of the robotic system. Overall, these results are profitable for energy-efficient design and performance optimization of tractor-trailer wheeled robot which is not only working in the greenhouse environment, but also employing in any structured environment with concrete flat surface.

Keywords: Wheeled mobile robot; Greenhouse robot; Motion energy; Longitudinal slip; Motion resistance force

Analysis of vehicle tire strength test

I.M. El Fahham, W.A. Crosby, A.I. Gaied

Journal of Terramechanics, Volume 105, 2023, Pages 1-9, ISSN 0022-4898

https://doi.org/10.1016/j.jterra.2022.10.001.(https://www.sciencedirect.com/science/article/pii/S0022489822000696)

Abstract: An experimental investigation is conducted to study the plunger test which represents the standard strength test for vehicle tires. Five different models of main brands are examined. The effect of applied load and internal pressure on the breaking energy of the tire are studied. Standard tensile tests are conducted on the same models to investigate the modes of failure of different specimens and the correlation between both tests. It was found that the increase of the internal pressure leads to a linear decrease in braking energy for all brands. The breaking energy was affected by the viscoelastic behavior of the rubbery components of the tire after the breakdown of the strengthening wires. Using statistical analysis, a correlation was found between the braking energy and the ratio between the elastic modulus and the tensile strength of the tire. This numerical correlation can be used by designers to simulate and predict the performance of the tire at different strength tests. On the other hand, the breaking energy was inversely related to the strain energy density.

Keywords: Tire; Plunger test; Tire strength test; Tensile test; Statistical analysis

Terrain mobility performance optimization: Fundamentals for autonomous vehicle applications Part II. Computational simulation, implementation for mobility design, and validation

Vladimir V. Vantsevich, David J. Gorsich, Jesse R. Paldan, Masood Ghasemi, Lee Moradi, Michael Letherwood

Journal of Terramechanics, Volume 104, 2022, Pages 59-85, ISSN 0022-4898

https://doi.org/10.1016/j.jterra.2022.06.001.(https://www.sciencedirect.com/science/article/pii/S0022489822000416)

Abstract: Based on an analysis of vehicle mobility performance indices in use, it is shown that an index for the optimization of autonomous vehicle mobility performance should be constituted as a set of technical parameters that should result directly from the interactive dynamics of tires and terrain and should be measurable and controllable in real-time. Besides, the combination of the parameters should characterize the vehicle’s technical productivity/efficiency (not energy efficiency), and thus, enable the estimation and control of vehicle mobility performance. If such requirements are satisfied, the index can be optimized and optimization results can facilitate autonomous control design. This article provides results of a study to address the above-formulated requirements in the proposed mobility performance index. Part II discusses the computational results of mobility performance optimization for a 4x4 vehicle simulated on three homogeneous terrains and split terrains on flat surface and on slopes, with and without drawbar pull. Additionally, the vehicle with three conventional driveline systems is simulated in the same terrain conditions, and a detailed analysis establishes dependences between the optimal tire slippages and optimal circumferential forces of the wheels and their correlation to those provided by the driveline systems. Advantages of the mobility optimization for control design are explained and discussed. It is also concluded that the use of energy efficiency indices in mobility performance assessment can be considered as a supplementary, but not the primary subject-heading of the vehicle mobility performance. The mobility performance optimization directly contributes to mobility design that is illustrated by conceptual implementation of the optimization results in two driveline systems of the 4x4 vehicle: a driveline with positive engagement of the power-dividing units and a virtual driveline that serves for fully electric vehicles with in-wheel motors. Finally, a verification of the mobility optimization results and validation of the proposed mobility performance index is conducted through statistics-based assessment against experimental wheel circumferential forces and tire slippages.

Keywords: Autonomous vehicle; Global optimization; Wheel mobility performance; Vehicle mobility performance

Terrain mobility performance optimization: Fundamentals for autonomous vehicle applications. Part I. New mobility indices: Optimization and analysis

Vladimir V. Vantsevich, David J. Gorsich, Jesse R. Paldan, Masood Ghasemi, Lee Moradi

Journal of Terramechanics, Volume 104, 2022, Pages 31-47, ISSN 0022-4898

https://doi.org/10.1016/j.jterra.2022.09.001.(https://www.sciencedirect.com/science/article/pii/S002248982200057X)

Abstract: Based on an analysis of vehicle mobility performance indices in use, it is shown that an index for the optimization of autonomous vehicle mobility performance should be constituted as a set of technical parameters that result directly from the interactive dynamics of tires and terrain and should be measurable and controllable in real-time. In addition, the combination of the parameters should characterize the vehicle’s technical productivity/efficiency (not energy efficiency), and thus, enable the estimation and control of vehicle mobility performance. If such requirements are satisfied, the index can be optimized and optimization results can facilitate autonomous control design. This article provides results of a study to address the above-formulated requirements in the proposed mobility performance index. In Part I of this article, wheel mobility performance is characterized first by the wheel circumferential force and the actual linear velocity. The proposed wheel mobility performance (WMP) index mathematically relates the wheel circumferential force and velocity to the theoretical maximum performance. Thus, the actual performance can be evaluated in terms of the theoretical maximum performance in a similar manner that the actual energy efficiency is compared to its theoretical maximum, i.e., to unity. The WMP-index is then extended to multi-wheel vehicles. The proposed vehicle mobility performance (VMP) index relates the traction and velocity characteristics of all wheels to a theoretical maximum performance. Founded on the circumferential force and velocity characteristics of the wheels, the VMP-index mathematically reflects the influence of the power distribution among the wheels on the vehicle mobility performance. Hence, the VMP-optimization is formulated as an examination for the optimal tire slippages. Essentially, their combination characterizes the optimal wheel power split, and consequently, the best set of the wheel circumferential forces and the vehicle actual velocity for the maximum mobility performance in a given terrain condition. The tire slippages are subject to lower and upper bound constraints. The lower bound ensures positive tire slippages, and thus, positive traction of the wheels. The upper bound is imposed in the form of characteristic slippages such that exceeding them drives the wheels into an extremely nonlinear zone of the traction characteristic. In this zone, the wheel mobility margins drop significantly and some or all wheels can easily be immobilized. Further, the optimization is subject to the vehicle longitudinal dynamics, which sets the summation of the wheel circumferential forces equal to the motion resistance forces. By applying Lagrange Multipliers (LMs) to the objective function, a system of equations is arranged to compute the optimal tire slippages that correspond to the necessary conditions of an extremum of the objective function. The strict monotonicity property of the LM-based equations is then examined and the uniqueness of the solution is exhibited. Finally, the Hessian theory for a constrained optimal problem is used to prove that the solution is globally minimum. Part II discusses the computational results of mobility performance optimization for a 4x4 vehicle simulated on three homogeneous terrains and split terrains on flat surface and on slopes, with and without drawbar pull. Additionally, the vehicle with three conventional driveline systems is simulated in the same terrain conditions, and a detailed analysis establishes dependences between the optimal tire slippages and optimal circumferential forces of the wheels and their correlation to those provided by the driveline systems. Advantages of the mobility optimization for control design are explained and discussed. It is also concluded that the use of energy efficiency indices in mobility performance assessment can be considered as a supplementary, but not the primary subject-heading of the vehicle mobility performance. The mobility performance optimization directly contributes to mobility design that is illustrated by conceptual implementation of the optimization results in two driveline systems of the 4x4 vehicle: a driveline with positive engagement of the power-dividing units and a virtual driveline that serves for fully electric vehicles with in-wheel motors. Finally, a verification of the mobility optimization results and validation of the proposed mobility performance index is conducted through statistics-based assessment against experimental wheel circumferential forces and tire slippages.

Keywords: Autonomous vehicle; Global optimization; Wheel mobility performance; Vehicle mobility performance

Experimental investigation of tire traction performance on granular terrain

Haiyang Zeng, Wei Xu, Mengyan Zang

Journal of Terramechanics, Volume 104, 2022, Pages 49-58, ISSN 0022-4898

https://doi.org/10.1016/j.jterra.2022.09.002.(https://www.sciencedirect.com/science/article/pii/S0022489822000581)

Abstract: In this work, an indoor soil bin traction measurement system is developed to systematically investigate the traction behavior of an off-road tire in interaction with granular terrain. The system is composed of a soil bin, a single wheel test device, a soil mixing/compaction device and its control and data acquisition system. Then the traction performance parameters such as the wheel traction force, sinkage, soil deformation and/or failure mechanism are obtained and investigated by using the system under different working conditions (tire slip, wheel load, tread pattern, granular medium). The experimental results show that the wheel traction force and sinkage present high linear correlation with the tire slip and wheel load. The wheel traction force and sinkage are also found to be directly influenced by the tire tread patterns and granular media. Moreover, with the increase of slip, the shear failure of the soil terrain behind and under the tire becomes more obvious, and the ruts become more blurred. The trend of shear failure mode of the granular terrain from local shear failure to overall failure is becoming ever more obvious. However, under the same tire slip, the wheel loads (7663 N, 10163 N and 12663 N) have little effect on the failure mode of soil terrain. Finally, the experiments indicate that the trafficability of the off-road tires on the gravel terrain is better than that on the sand terrain. The traction performance of the groove tires under the same soil conditions is better than that of the smooth tires.

Keywords: Soil bin measurement system; Traction performance; Tire-soil interaction; Off-road tires; Granular terrain