Modelling of off-road wheeled vehicles for real-time dynamic simulation

Peiret, Albert; Karpman, Eric; Kovâcs, László; Kövecses, József; Holz, D. E.; Teichmann, Marek

doi:10.1016/j.jterra.2021.04.001

Cited by 15 publications

(5 citation statements)

References 16 publications

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“…UKFs are proposed to estimate the nonlinear system based on correlated measurement models that form a network of sensors with the size of the number of steerable wheels. The performance of the proposed estimator is evaluated in a high-fidelity Software-in-the-loop Simulation (SILS) of a sixwheel Lunar rover that is coded in MATLAB and CM Lab's Vortex Studio [39]. In comparison studies that consider four different fusion strategies and five different motion phases, the superior real-time performance of the proposed methodology is demonstrated.…”

Section: Statement Of Contributionsmentioning

confidence: 99%

“…The control torque command computed by ( 86) is then applied to the digital twin of the WMR under study modeled in Vortex Studio. Vortex Studio is a high-fidelity simulation platform developed by CM Labs Simulation Inc, containing a real-time multi-body-dynamics simulation engine and various sophisticated wheel-soil interaction models [39]. The digital twin of the WMR under study is modeled as six wheels assembled on the main body using the car wheel constraints.…”

Section: B Controller Designmentioning

confidence: 99%

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Sequential Track Fusion in UKF-based Multi-Sensor Networks: A Case of Slip Estimation in Wheeled Mobile Robots

Zarei¹,

Chhabra²,

Mottaghi³

2023

Preprint

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Accurate wheel slip estimation facilitates Wheeled Mobile Robots (WMRs) with improved localization and traversability monitoring which are crucial to their autonomy in challenging environments. Although distributed track-level fusion offers better computational efficiency, often sensor-level fusion is adopted in slip estimators. Extending upon our earlier work, we develop a novel explicit track-to-track fusion algorithm for UKF-based multi-sensor networks that has immediate application to slip ratio estimation in WMRs. The algorithm demonstrates better consistency compared to the existing fusion techniques, since it implements an optimal fusion rule to sequentially combine local tracks. It also saves computational power due to the recursive propagation of cross-covariance matrices based on the statistical linearization technique, instead of performing online optimizations. We prove that this recursion only requires the information of the first and last tracks in a sequence if all local tracks are unbiased. We rigorously study various key properties of the developed fusion algorithm and show its superior level of confidence when compared to the two prominent fusion methods of sequential and batch covariance intersection. The slip ratio estimation in a six-wheel WMR is considered as a case study, where the steerable wheel sets act as a network of sensors. The proposed slip estimator works based on the rigid body kinematics and readings of purely proprioceptive sensors, i.e., an inertial measurement unit and encoders. The slip estimator's performance is evaluated in a high-fidelity software-in-the-loop simulation environment connecting MATLAB and CM Lab's Vortex Studio software. In a comparison study that considers four rival strategies, we show the superiority of the proposed fusion method offering a balance between consistency, accuracy, and speed in real-time slip estimations.

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Section: Statement Of Contributionsmentioning

confidence: 99%

Section: B Controller Designmentioning

confidence: 99%

Sequential Track Fusion in UKF-based Multi-Sensor Networks: A Case of Slip Estimation in Wheeled Mobile Robots

Zarei¹,

Chhabra²,

Mottaghi³

2023

Preprint

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“…To alleviate wheel fighting, we orthogonally project the obtained vector of optimal control distribution τ * a from ( 35) or (37) onto the subspace of solutions of (41). Accordingly, the sub-optimal solution τ * ′ a is obtained by…”

Section: Wheel-fighting Considerationmentioning

confidence: 99%

“…6). Vortex Studio is a high-fidelity multi-body dynamics simulator equipped with various wheel-ground interaction models, developed by CM Labs Simulation Inc. [40], [41]. The I.…”

Section: Implementation On a Six-wheel Lunar Rovermentioning

confidence: 99%

Fast Traction Control of Rovers on Prescribed Dynamic Trajectories with Wheel-Fighting Consideration

Mottaghi¹,

Chhabra²,

Huang³

2022

Preprint

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To reliably localize and control wheeled autonomous rovers, their controllers must keep the wheels away from traction loss. In this paper, we develop a fast and practical traction control system for rovers that track dynamic trajectories on rough firm terrains, leveraging their normally existing redundant control directions. Trajectory-tracking performance is guaranteed by input-output linearizing a nonholonomic model of the system and employing an appropriate stabilizing control law. We propose a novel methodology to optimally lift the control signals at the rover’s output level to determine the control actions that enhance the system’s traction without affecting the tracking performance. The methodology uses the knowledge of wheels’ friction coefficients and estimation of normal and tractive forces based on a nonholonomic rover model to optimally distribute the tractive forces among the wheels. The novelty is in redefining the optimization problem in both lateral and longitudinal directions that require minimum information about wheel-ground interactions and leads to linear optimality conditions. We define the notion of total required force/moment at system’s center of mass to (i) introduce reference directions for tractive forces in the proposed cost functions, and (ii) identify the rover wheels fighting against the motion. To prevent wheel-fighting, we find sub-optimal solutions that suppress tractive forces at the fighting wheels. The proposed traction control system is implemented on a six-wheel autonomous Lunar rover and its efficacy is investigated by a developed software-in-the-loop simulation environment using Vortex Studio. This software simulates a 3-dimensional digital twin of the system, with different terrain and tire model options. When compared to the conventional pseudo-inverse solution, the developed traction controller demonstrates improved overall traction and it saves the rover from traction loss.

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“…In this section, the accuracy of the estimated tractive forces and ground normal reaction forces is evaluated by developing a software-in-the-loop simulation platform using Vortex Studio 2020b. Vortex Studio is a high-fidelity simulation platform developed by CM Labs Simulation Inc, providing a real-time multi-body-dynamics simulation engine along with different wheel-soil interaction tire models [99][100][101][102][103]. First the mechanism is developed as six wheels assembled on the main body using the defined car wheel constraint.…”

Section: Validation Of Estimated Valuesmentioning

confidence: 99%

Optimal Robust Output-Tracking of Autonomous Rovers with Dynamic Traction Control

Mottaghi¹

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I would like to acknowledge my amazing supervisor Dr.Chhabra for all his help during this journey. Your guidance has been so important in shaping my engineering vision and problem solving abilities. I would also like to show gratitude to my fantastic co-supervisor Dr.Huang. I will never forget all your assistance, support and kindness. Furthermore, I want to thank Eric Karpman for his help in working with Vortex Studio software. Finally, I wish to acknowledge the support and great love of my family.vi

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Modelling of off-road wheeled vehicles for real-time dynamic simulation

Cited by 15 publications

References 16 publications

Sequential Track Fusion in UKF-based Multi-Sensor Networks: A Case of Slip Estimation in Wheeled Mobile Robots

Sequential Track Fusion in UKF-based Multi-Sensor Networks: A Case of Slip Estimation in Wheeled Mobile Robots

Fast Traction Control of Rovers on Prescribed Dynamic Trajectories with Wheel-Fighting Consideration

Optimal Robust Output-Tracking of Autonomous Rovers with Dynamic Traction Control

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