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Journal Article

Wheel Chock Key Design Elements and Geometrical Profile for Truck Vehicle Restraint

2018-06-06
Abstract Wheel chocks are rather simple compliant mechanisms for stabilizing vehicles at rest. However, chocks must be carefully designed given the complex interaction between the chock and the tire/suspension system. Despite their importance for safety, literature is surprisingly limited in terms of what makes a wheel chock efficient. Using simple but reliable quasi-static mechanical models, this study identifies mechanical requirements that help to avoid a number of failure modes associated with many existing wheel chocks. Given that chock grounding is not always possible, a chock’s maximum restraining capacity is only obtained when the wheel is completely supported by the chock. A generic chock profile is proposed to achieve this objective while mitigating undesirable failure modes. The profile is based on fundamental mechanical principles and no assumption is made on the load interaction between the chock and the wheel.
Journal Article

Tire Side Force Characteristics with the Coupling Effect of Vertical Load and Inflation Pressure

2018-11-09
Abstract The tire vertical load and inflation pressure have great influence on tire steady- and non-steady-state characteristics and, consequently, on the vehicle handling and stability. The objective of this article is to reveal the coupling effect of tire vertical load and inflation pressure on tire characteristics and then introduce an improved UniTire side force model including such coupling effect through experimental and theoretical analysis. First, the influence of the tire vertical load and inflation pressure on the tire characteristics is presented through experimental analysis. Second, the theoretical tire cornering stiffness and lateral relaxation length model are introduced to study the underlying mechanism of the coupling effect. Then, an improved UniTire side force model including the coupling effect of tire vertical load and inflation pressure is derived. Finally, the proposed improved UniTire side force model is validated through tire steady-state and transient data.
Journal Article

Performance Margin for Geometric Road Design

2018-08-08
Abstract Although several methods exist for measuring the performance capability of a vehicle, many require detailed knowledge of the forces acting at each tire contact patch or do not account for both the vehicle dynamics and the road geometry. A simple vehicle model is proposed to estimate the upper limit of performance capability for a given operating condition (the Performance Envelope) based on the Effective Friction and the road geometry (slope and cross-slope). The Effective Friction accounts for both the vehicle dynamics and road surface properties and is estimated, through simulation or experimentation, using two standard vehicle dynamics tests: constant radius cornering and straight-line braking. The Performance Margin is defined as the additional performance capability available before the vehicle reaches the Performance Envelope, both represented in the intuitive units of gravity.
Journal Article

PSO-Fuzzy Gain Scheduling of PID Controllers for a Nonlinear Half-Vehicle Suspension System

2018-11-19
Abstract The present article addresses the gain scheduling of proportional-integral-differential (PID) controllers using fuzzy set theory coupled with a metaheuristic optimization technique to control the vehicle nonlinear suspension system. The nonlinearities of the vehicle suspension system are due to the asymmetric piecewise dampers, quadratic tire stiffness, and the cubical spring stiffness. Conventional PID controller suffers from the low performance subject to modeling nonlinearities, while fuzzy logic controller (FLC), as a universal approximator, has the capacity to deal with the nonlinear, stochastic, and complex models. However, finding the optimal Mamdani FLC rules is still a challenging task in addition to a proper architecture of the membership functions (MFs). As a remedy to this drawback, particle swarm optimization (PSO) technique is employed in this article to improve the efficiency of the FLC-based PID controllers.
Journal Article

Multi-Chamber Tire Concept for Low Rolling-Resistance

2019-04-08
Abstract Rolling-resistance is leading the direction of numerous tire developments due to its significant effect on fuel consumption and CO2 emissions considering the vehicles in use globally. Many attempts were made to reduce rolling-resistance in vehicles, but with no or limited success due to tire complexity and trade-offs. This article investigates the concept of multiple chambers inside the tire as a potential alternative solution for reducing rolling-resistance. To accomplish that, novel multi-chamber designs were introduced and numerically simulated through finite-element (FE) modeling. The FE models were compared against a standard design as the baseline. The influences on rolling-resistance, grip, cornering, and mechanical comfort were studied. The multi-chambers tire model reduced rolling-resistance considerably with acceptable trade-offs. Independent air volumes isolating tread from sidewalls would maintain tire’s profile effectively.
Journal Article

Investigation of a Six-Phase Interior Permanent Magnet Synchronous Machine for Integrated Charging and Propulsion in EVs

2018-04-17
Abstract Merits such as reduced weight, overall and operational costs of the electric vehicle (EV) while providing level 3 charging capability, are propelling research on integrated charging (IC) technology for EVs. Since the same interior permanent magnet synchronous machine (IPMSM) is used during IC and traction conditions, it is important to understand the behavior of the machine during these conditions and optimally design the machine. Hence, firstly, this paper presents a case study on performance of a laboratory 3-phase IPMSM under IC and traction conditions. Thereafter, understanding the challenges such as low magnet operating point, losses and torque oscillation in 3-phase IPMSM during IC, a 6-phase IPMSM with an unconventional configuration is investigated to yield traction characteristics like that of the 3-phase IPMSM and mitigate challenges during IC. In the process, mathematical model of the 6-phase IPMSM is developed employing the dq-axis theory.
Journal Article

Introducing the Modified Tire Power Loss and Resistant Force Regarding Longitudinal Slip

2018-04-18
Abstract Investigation of vehicle resistant forces and power losses is of crucial importance owing to current state of energy consumption in transport sector. Meanwhile, considerable portion of resistant forces in a ground vehicle is traced back to tires. Pneumatic tires are known to be a source of energy dissipation as a consequence of their viscoelastic nature. The current study aims to provide a modification to tire resistance by considering the power loss in a tire due to longitudinal slip. The modified tire resistance is comprised of rolling resistance and a newly introduced resistance caused by tire slip, called slip resistance. The physical model is chosen for parameters sensitivity study since the tractive force is described in this model via tangible physical parameters, e.g. tire tangential stiffness, coefficient of friction, and contact patch length.
Journal Article

In-Plane Flexible Ring Tire Model Parameter Identification: Optimization Algorithms

2018-05-03
Abstract Parameter identification is an important part of tire model development. The prediction performance of a tire model highly depends on the identified parameter values of the tire model. Different optimization algorithms may yield different tire parameters with different computational accuracy. It is essential to find out which optimization algorithm is most likely to generate a set of parameters with the best prediction performance. In this study, four different MATLAB® optimization algorithms, including fminsearchcon, patternsearch, genetic algorithm (GA), and particleswarm, are used to identify the parameters of a newly proposed in-plane flexible ring tire model. The reference data used for parameter identification are obtained through a ADAMS FTire® virtual cleat test. After parameters are identified based on above four algorithms, their performances are compared in terms of effectiveness, efficiency, reliability, and robustness.
Journal Article

Improving Vehicle Rollover Resistance Using Fuzzy PID Controller of Active Anti-Roll Bar System

2018-12-20
Abstract The active anti-roll bar (AARB) system in vehicles has recently become one of the research hotspots in the field of vehicle technology to improve the vehicle’s active safety. In most off-road vehicles, high ground clearance is required while keeping all wheels in contact with the ground in order to improve traction and maintain load distribution among the wheels. A problem however arises in some types of the off-road vehicles when the vehicle is operated at high speeds on smooth roads. In such condition, the combination of the vehicle’s center of gravity position, large suspension stroke, and soft spring construction creates a stability problem, which could make the vehicle liable to rollover. This article analyzes a comparison of stability performance between passive and active anti-roll bar systems to improve rolling resistance. For active systems, two control strategies will be investigated. The conventional PID controller is firstly investigated and taken as a reference.
Journal Article

Force Transmission Characteristics for a Loaded Structural-Acoustic Tire Model

2018-10-23
Abstract Concerns about tire noise radiation arise partly from city traffic planning, environmental protection, and pedestrian safety standpoints, while from the vehicle passengers’ perspective, noise transmitted to the vehicle interior is more important. It is the latter concern that is addressed in this article. Sound-absorbing materials generally offer good absorption at higher frequencies, but the reduction of relatively low frequency, structure-borne tire noise is a continuing focus of many auto manufacturers. A tire’s internal, acoustic cavity resonance is a very strong contributing factor to tire-related structure-borne noise, and it can easily be perceived by passengers. Some reduction of vehicle cabin noise can be achieved through the insertion of sound-absorbing material in the tires. However, apart from the additional cost for such tires, there is also an increased complexity when repairing them because of the need to avoid damaging the sound-absorptive lining.
Journal Article

Extending the Magic Formula Tire Model for Large Inflation Pressure Changes by Using Measurement Data from a Corner Module Test Rig

2018-03-05
Abstract Since the tire inflation pressure has a significant influence on safety, comfort and environmental behavior of a vehicle, the choice of the optimal inflation pressure is always a conflict of aims. The development of a highly dynamic Tire Pressure Control System (TPCS) can reduce the conflict of minimal rolling resistance and maximal traction. To study the influence of the tire inflation pressure on longitudinal tire characteristics under laboratory conditions, an experimental sensitivity analysis is performed using a multivalent usable Corner Module Test Rig (CMTR) developed by the Automotive Engineering Group at Technische Universität Ilmenau. The test rig is designed to analyze suspension system and tire characteristics on a roller of the recently installed 4 chassis roller dynamometer. Camber angle, toe angle and wheel load can be adjusted continuously. In addition, it is possible to control the temperature of the test environment between −20 °C and +45 °C.
Journal Article

A Review on Physical Mechanisms of Tire-Pavement Interaction Noise

2019-05-16
Abstract Tire-pavement interaction noise (TPIN) dominates for passenger cars above 40 km/h and trucks above 70 km/h. Numerous studies have attempted to uncover and distinguish the basic mechanisms of TPIN. However, intense debate is still ongoing about the validity of these mechanisms. In this work, the physical mechanisms proposed in the literature were reviewed and divided into three categories: generation mechanisms, amplification mechanisms, and attenuation mechanisms. The purpose of this article is to gather the published general opinions for further open discussions.
Journal Article

A Probabilistic Approach to Hydroplaning Potential and Risk

2019-01-30
Abstract A major contributor to fatal vehicle crashes is hydroplaning, which has traditionally been reported at a specific vehicle speed for a given operating condition. However, hydroplaning is a complex phenomenon requiring a holistic, probabilistic, and multidisciplinary approach. The objective of this article is to develop a probabilistic approach to predict Hydroplaning Potential and Risk that integrates fundamental understanding of the interdependent factors: hydrology, fluid-solid interactions, tire mechanics, and vehicle dynamics. A novel theoretical treatment of Hydroplaning Potential and Risk is developed, and simulation results for the prediction of water film thickness and Hydroplaning Potential are presented. The results show the advantages of the current approach which could enable the improvement of road, vehicle, and tire design, resulting in greater safety of the traveling public.
Journal Article

A Combination of Intelligent Tire and Vehicle Dynamic Based Algorithm to Estimate the Tire-Road Friction

2019-04-08
Abstract One of the most important factors affecting the performance of vehicle active chassis control systems is the tire-road friction coefficient. Accurate estimation of the friction coefficient can lead to better performance of these controllers. In this study, a new three-step friction estimation algorithm, based on intelligent tire concept, is proposed, which is a combination of experiment-based and vehicle dynamic based approaches. In the first step of the proposed algorithm, the normal load is estimated using a trained Artificial Neural Network (ANN). The network was trained using the experimental data collected using a portable tire testing trailer. In the second step of the algorithm, the tire forces and the wheel longitudinal velocity are estimated through a two-step Kalman filter. Then, in the last step, using the estimated tire normal load and longitudinal and lateral forces, the friction coefficient can be estimated.
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