A Comprehensive Framework for Simulating Dynamics of an Off-Road Vehicle in Unconstructed Environments

2018 ◽  
Author(s):  
Shahab Karimi ◽  
Ardalan Vahidi ◽  
Paramsothy Jayakumar
Keyword(s):  
Iterative Algorithm ◽  
Vehicle Dynamics ◽  
Degrees Of Freedom ◽  
Commercial Vehicle ◽  
Contact Point ◽  
Dynamics Analysis ◽  
Tire Model ◽  
Road Vehicles ◽  
Rotation Matrices ◽  
Comprehensive Framework

Vehicle dynamics analysis becomes more demanding for off-road vehicles’ mobility in unconstructed environments. Significant vehicle orientation changes, extreme changes in ground elevation, and uneven ground profiles at tire-road contact regions, etc. must be taken into account. In addition, the simulation computations should strike a balance between the speed and the accuracy of the results. In this paper, a model with fourteen degrees of freedom is used for vehicle dynamics analysis. Integrated within the model, a comprehensive tire model and a system of instantaneous rotation matrices are programmed to address the effect of more extreme ground profiles on the vehicle dynamics. Additionally, an iterative algorithm is developed to explore and determine the tire-road contact point. The results of simulation for two random scenarios are validated versus a commercial vehicle dynamics software showing consistency of results.

The Impact of Tire Measurement Data on Tire Modeling and Vehicle Dynamics Analysis

2010 ◽  
Vol 38 (2) ◽  
pp. 155-180 ◽  
Author(s):  
Thomas Hüsemann ◽  
Mark Wöhrmann
Keyword(s):  
Vehicle Dynamics ◽  
Measurement Data ◽  
Simulation Models ◽  
Major Influence ◽  
Dynamics Analysis ◽  
Tire Model ◽  
Chassis Component ◽  
Measurement Results ◽  
Tire Modeling ◽  
The Impact

Abstract Computer aided engineering tools play an important role in today’s vehicle development process. Today, overall vehicle dynamics analysis and chassis component fatigue resistance investigations can be carried out without the need for existing prototype hardware versions of the corresponding vehicle. An accurate tire model is a key element in precise modeling of the vehicle and its components. All forces acting on the vehicle (except for aerodynamic forces) are transferred via the tires. Therefore, the tire and its modeled characteristics have a major influence on the results of vehicle dynamics analysis. At present, many tire simulation models are available for application in vehicle dynamics analysis. To obtain the best possible performance from these models, a number of different tire measurements are required to support the tire model parameter identification process. This paper presents a review of different tire simulation models and their required tire measurements. Depending on the test rigs used and the measurement procedures applied, the tire measurement results may be somewhat different. What is the impact of these differences on the tire modeling performance and the vehicle dynamics analysis output? This paper gives an answer.

A Modified Dugoff Tire Model for Combined-slip Forces

2010 ◽  
Vol 38 (3) ◽  
pp. 228-244 ◽  
Author(s):  
Nenggen Ding ◽  
Saied Taheri
Keyword(s):  
Vehicle Dynamics ◽  
Tire Model ◽  
Magic Formula ◽  
Model Based ◽  
Proposed Model ◽  
Road Friction ◽  
On Line ◽  
Double Lane Change ◽  
Tire Forces ◽  
Tire Models

Abstract Easy-to-use tire models for vehicle dynamics have been persistently studied for such applications as control design and model-based on-line estimation. This paper proposes a modified combined-slip tire model based on Dugoff tire. The proposed model takes emphasis on less time consumption for calculation and uses a minimum set of parameters to express tire forces. Modification of Dugoff tire model is made on two aspects: one is taking different tire/road friction coefficients for different magnitudes of slip and the other is employing the concept of friction ellipse. The proposed model is evaluated by comparison with the LuGre tire model. Although there are some discrepancies between the two models, the proposed combined-slip model is generally acceptable due to its simplicity and easiness to use. Extracting parameters from the coefficients of a Magic Formula tire model based on measured tire data, the proposed model is further evaluated by conducting a double lane change maneuver, and simulation results show that the trajectory using the proposed tire model is closer to that using the Magic Formula tire model than Dugoff tire model.

scholarly journals Reconstruction of Relative Phase of Self-Transmitting Devices by Using Multiprobe Solutions and Non-Convex Optimization

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2459
Author(s):  
Rubén Tena Sánchez ◽  
Fernando Rodríguez Varela ◽  
Lars J. Foged ◽  
Manuel Sierra Castañer
Keyword(s):  
Iterative Algorithm ◽  
Degrees Of Freedom ◽  
Relative Phase ◽  
Low Cost ◽  
Initial Guess ◽  
Noise Model ◽  
Medium Size ◽  
Phase Reconstruction ◽  
Linear Combinations ◽  
Iterative Optimization Algorithm

Phase reconstruction is in general a non-trivial problem when it comes to devices where the reference is not accessible. A non-convex iterative optimization algorithm is proposed in this paper in order to reconstruct the phase in reference-less spherical multiprobe measurement systems based on a rotating arch of probes. The algorithm is based on the reconstruction of the phases of self-transmitting devices in multiprobe systems by taking advantage of the on-axis top probe of the arch. One of the limitations of the top probe solution is that when rotating the measurement system arch, the relative phase between probes is lost. This paper proposes a solution to this problem by developing an optimization iterative algorithm that uses partial knowledge of relative phase between probes. The iterative algorithm is based on linear combinations of signals when the relative phase is known. Phase substitution and modal filtering are implemented in order to avoid local minima and make the algorithm converge. Several noise-free examples are presented and the results of the iterative algorithm analyzed. The number of linear combinations used is far below the square of the degrees of freedom of the non-linear problem, which is compensated by a proper initial guess. With respect to noisy measurements, the top probe method will introduce uncertainties for different azimuth and elevation positions of the arch. This is modelled by considering the real noise model of a low-cost receiver and the results demonstrate the good accuracy of the method. Numerical results on antenna measurements are also presented. Due to the numerical complexity of the algorithm, it is limited to electrically small- or medium-size problems.

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