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Showing 88 results for Vehicle

A. Fotouhi, M. Montazeri, M. Jannatipour,
Volume 1, Issue 1 (1-2011)
Abstract

This paper presents the prediction of vehicle's velocity time series using neural networks. For this purpose, driving data is firstly collected in real world traffic conditions in the city of Tehran using advance vehicle location devices installed on private cars. A multi-layer perceptron network is then designed for driving time series forecasting. In addition, the results of this study are compared with the auto regressive (AR) method. The least root mean square error (RMSE) and median absolute percentage error (MDAPE) are utilized as two criteria for evaluation of predictions accuracy. The results demonstrate the effectiveness of the proposed approach for prediction of driving data time series.
E. Esmailzadeh, A. Goodarzii, M. Behmadi,
Volume 1, Issue 1 (1-2011)
Abstract

Improvement in braking performance and vehicle stability can be achieved through the use of braking systems whose brake force distribution is variable. Electronic braking force distribution has an important and serious role in the vehicle stopping distance and stability. In this paper a new approach will be presented to achieve the braking force distribution strategy for articulated vehicles. For this purpose, the mathematical optimization process has been implemented. This strategy, defined as an innovative braking force distribution strategy, is based on the wheel slips. The simulation results illustrate proposed strategy can significantly improve the vehicle stability in curved braking for different levels of vehicle deceleration
M. M. Tehrani, M. R. Hairi-Yazdi, Ba. Haghpanah-Jahromi, V. Esfahanian, M. Amiri, A. R. Jafari,
Volume 1, Issue 2 (6-2011)
Abstract

In this paper, an adaptive rule based controller for an anti-lock regenerative braking system (ARBS) of a series hybrid electric bus (SHEB) has been proposed. The proposed controller integrates the regenerative braking and wheel anti-lock functions by controlling the electric motor of the hybrid vehicle, without using any conventional mechanical anti-lock braking system. The performance of the proposed system is evaluated by a comprehensive vehicle dynamics model in MATLAB/Simulink. Using the designed ARBS, the braking and regenerative performances of SHEB have significantly improved in slippery roads while the slip ratios are kept between 0.15 and 0.20.
S. Sanaye, M. Dehghandokht,
Volume 1, Issue 3 (5-2011)
Abstract

Thermal modeling of an automotive cabin was performed in this paper to predict the inside cabin air temperature. To implement this task, thermal and ventilation loads were estimated and the mass and energy balance conservation equations for dry air and water vapor with considering a new parameter (air circulation ratio) as well as the balance equations of internal components of a cabin were derived and solved simultaneously. The performance of the proposed thermal modeling of a cabin was compared with the data collected from hot room experimental tests. These tests were run for various design parameters such as evaporating cooling load and cabin size (air volume inside cabin). The comparison of experimental and numerical results showed a good agreement. Parametric analysis with three parameters namely, vehicle speed, number of passengers, and A/C air mass flow rate was performed to investigate the effects of these parameters on cabin air temperature.
M. Abbasi, R. Kazemi, A. Ghafari Nazari,
Volume 1, Issue 3 (5-2011)
Abstract

Parametric design optimization of an automotive body crashworthiness improvement is presented. The thicknesses of parts are employed as design variables for optimization whose objective is to increase the maximum deceleration value of the vehicle center of gravity during an impact. Using the Taguchi method, this study analyzes the optimum conditions for design objectives and the impact factors and their optimal levels are obtained by a range analysis of the experiment results. A full frontal impact is implemented for the crashworthiness simulation in the nonlinear dynamic code, LS-DYNA. The controllable factors used in this study consist of the six inside foreheads structural parts, while design parameters are relevant thicknesses. The most interestingly the maximum deceleration of the vehicle center of gravity is reduced by 20% during a full frontal impact while several parts experience mass reduction.
D. Younesian, A.a. Jafari, R. Serajian,
Volume 1, Issue 3 (5-2011)
Abstract

Nonlinear hunting speeds of railway vehicles running on a tangent track are analytically obtained using Hopf bifurcation theory in this paper. The railway vehicle model consists of nonlinear primary yaw dampers, nonlinear flange contact stiffness as well as the clearance between the wheel flange and rail tread. Linear and nonlinear critical speeds are obtained using Bogoliubov method. A comprehensive parametric study is then carried out and effects of different parameters like the magnitudes of lateral clearance, damping values, wheel radius, bogie mass, lateral stiffness and the track gauge on linear and nonlinear hunting speeds are investigated.
M. Bidarvatan, M. Shahbakhti, S.a. Jazayeri,
Volume 1, Issue 3 (5-2011)
Abstract

Homogenous Charge Compression Ignition (HCCI) engines hold promise of high fuel efficiency and low emission levels for future green vehicles. But in contrast to gasoline and diesel engines, HCCI engines suffer from lack of having direct means to initiate combustion. A combustion timing controller with robust tracking performance is the key requirement to leverage HCCI application in production vehicles. In this paper, a two-state control-oriented model is developed to predict HCCI combustion timing for a range of engine operation. The experimental validation of the model confirms the accuracy of the model for HCCI control applications. An optimal integral state feedback controller is designed to control the combustion timing by modulating the ratio of two fuels. Optimization methods are used in order to determine the controller’s parameters. The results demonstrate the designed controller can reach optimal combustion timing within about two engine cycles, while showing good robustness to physical disturbances.
M. Salehpour, A. Jamali, N. Nariman-Zadeh,
Volume 1, Issue 4 (10-2011)
Abstract

In this paper, multi-objective uniform-diversity genetic algorithm (MUGA) with a diversity preserving mechanism called the ε-elimination algorithm is used for Pareto optimization of 5-degree of freedom vehicle vibration model considering the five conflicting functions simultaneously. The important conflicting objective functions that have been considered in this work are, namely, vertical acceleration of seat, vertical velocity of forward tire, vertical velocity of rear tire, relative displacement between sprung mass and forward tire and relative displacement between sprung mass and rear tire. Further, different pairs of these objective functions have also been selected for 2-objective optimization processes. The comparison of the obtained results with those in literature demonstrates the superiority of the results of this work. It is shown that the results of 5-objective optimization include those of 2-objective optimization and, therefore, provide more choices for optimal design of vehicle vibration model.
F. Javid, E. Esmailzadeh, D. Younesian,
Volume 1, Issue 4 (10-2011)
Abstract


N. Tavassoli, A. Darvizeh, M. Darvizeh,
Volume 2, Issue 1 (1-2012)
Abstract

Car body lightening and crashworthiness are two important objectives of car design. Due to their excellent performance, composite materials are extensively used in the car industries. In addition, reducing the weight of vehicle is effective in decreasing the fuel consumption. Hat shape energy absorber is used in car’s doors for side impact protection. The aim of these numerical models and experimental tests is to unveil some important fact about using composite materials in hat shape energy absorber and also show the effect of orientation angles on the amount of energy absorption. The effects of different orientation angles on crushing behavior of hat shape structure are presented.
Sh. Azadi, Z. Taherkhani,
Volume 2, Issue 1 (1-2012)
Abstract

This paper develops an automatic parking algorithm based on a fuzzy logic controller with the vehicle pose for the input and the steering angle for the output. In this way some feasible reference trajectory path have been introduced according to geometric and kinematic constraints and nonholonomic constraints to simulate motion path of car. Also a novel method is used for parking space detection according to image processing. A fuzzy controller according to experiments of skilled driver and path planning is designed, and then fuzzy rules are tuned and finally fuzzy membership functions are optimized using genetic algorithm. Simulation results illustrate the effectiveness of the developed schemes
B. Mashadi, A. Aghaei,
Volume 2, Issue 1 (1-2012)
Abstract

the primary objective of this work is to introduce a gear ratio selection strategy for a CVT equipped vehicle and show its effectiveness on the fuel consumption reduction. AFuzzy control algorithm is designed for this purpose. Anonlinear model is developed for simulating the longitudinal vehicle dynamics with accelerator pedal applied by the driver as an input. In order that pedal input values can be used for evaluation of control strategy, a pedal cycle concept was introduced. With the help of these cycles different driving conditions were simulated and the fuel consumption results were obtained using Advisor software. Results showed that the control system was successful in reducing the fuel consumption, especially in low acceleration driving cycles
A. Khodayari, A. Ghaffari,
Volume 2, Issue 1 (1-2012)
Abstract

Car-following models, as the most popular microscopic traffic flow modeling, is increasingly being used by transportation experts to evaluate new Intelligent Transportation System (ITS) applications. A number of factors including individual differences of age, gender, and risk-taking behavior, have been found to influence car-following behavior. This paper presents a novel idea to calculate the Driver-Vehicle Unit (DVU) instantaneous reaction delay of DVU as the human effects. Unlike previous works, where the reaction delay is considered to be fixed, considering the proposed idea, three input-output models are developed to estimate FV acceleration based on soft computing approaches. The models are developed based on the reaction delay as an input. In these modeling, the inputs and outputs are chosen with respect to this feature to design the soft computing models. The performance of models is evaluated based on field data and compared to a number of existing car-following models. The results show that new soft computing models based on instantaneous reaction delay outperformed the other car-following models. The proposed models can be recruited in driver assistant devices, safe distance keeping observers, collision prevention systems and other ITS applications.
M. Shahab, M. Moavenian,
Volume 2, Issue 2 (4-2012)
Abstract

Vehicle driveline system and its working accuracy play an important role in the performance of car. The purpose of this study is to provide an appropriate mechanism for investigating, identifying and determining the position and size of defects in the vehicle power transmission system. This is based on the patterns of the residual signal, obtained from a simulated model of the system. Neuro-fuzzy networks have been used in diagnosis of defects because of its specific advantages and capabilities in pattern recognition. Simulation results demonstrate that the resulting fault detection system is able to properly locate the fault types under all test conditions, and is sensitive also to fault size. Test and simulation results using MATLAB software is given at the end.
J. Marzbanrad, M. Alahyari Beyg,
Volume 2, Issue 2 (4-2012)
Abstract

In this paper, the acoustic environment in a vehicle cabin under the influence of highfrequencies aerodynamic sources has been studied. Some panels on the windshield, the roof, the doors, the front pillars, and the floor of a vehicle simulated as input source of noise when the car is moving at high speed, i.e. 112 km/h. The status of vehicle cabin in each of these modes has been studied and compared to each other. There are some methods to simulate acoustic behavior of a vehicle cavity such as Finite Elements or Statistical Energy Analysis methods. A brief overview for Statistical Energy Analysis (SAE) is stated. In this study, the statistical energy method is used for determination of acoustic analysis. Auto SEA software is used to simulate and estimate the amount of sound pressure level. In addition, sound pressure formulation presented and used for comparison in vehicle cabin points and with experimental results for validation. Also, considering viscoelastic materials, a common form of material nonbinding panel has determined. The result shows that the roof is the most important panel in acoustic analysis under influence of aerodynamic sources. Accordingly, this panel has more effectiveness in optimization to control sound pressure level in a vehicle cabin. In addition, the amount of reduction in sound pressure level (SPL) in the cabin with viscoelastic material is presented as it could diminish the vibration of plates. In addition, the effect of using acoustic glasses is presented. Finally, the SPL effect of passenger position including front and rear is investigated and compared


S.m. Shariatmadar, M. Manteghi, M. Tajdari,
Volume 2, Issue 2 (4-2012)
Abstract

Non-linear characteristic of tire forces is the main cause of vehicle lateral dynamics instability, while direct yaw moment control is an effective method to recover the vehicle stability. In this paper, an optimal linear quadratic regulator (LQR) controller for roll-yaw dynamics to articulated heavy vehicles is developed. For this purpose, the equations of motion obtained by the MATLAB software are coded and then a control law is introduced by minimizing the local differences between the predicted and the desired responses. The influence of some parameters such as the anti roll bar, change the parameters of the suspension system and track wide in articulated heavy vehicles stability has been studied. The simulation results show that the vehicle stability can be remarkably improved when the optimal linear controller is applied
N. Gajarlawar, G. Amba Prasad Rao,
Volume 2, Issue 3 (7-2012)
Abstract

The current regulated particle metric in vehicle emissions is the total mass, while during last decade interest in number size distribution has increased. Various international studies on epidemiology and toxicology have reported the adverse effect of the particle matter on public health. The UNECE group of experts on pollution and energy (GRPE) under particle measurement program (PMP) are under the process of finalization long term certification standard concerning particle emissions. The current study was done in order to investigate the number concentration from a range of Indian multi utility vehicles. These were equipped with various sizes of diesel engine over the new European driving cycle (NEDC) cycle using same oil specification. The vehicles chosen were meeting emission norms ranging from Euro3 (E-3) to Euro5 (E-5) and using the corresponding fuel specification as specified for the norms. In order to meet the strict emission norms, penetration of common rail injection system in the Indian market is inevitable. The use of higher injection pressure, advanced after treatment systems such as diesel particle filters (DPF), is the motivation for the work to access the number concentration, an important metric of particle matter in view of future emission norms. It is clearly revealed that different vehicles equipped with different capacity engines exhibits similar diesel particle emission characteristics. Also, as the particle mass is decreasing with the stringent emission norms reduces the particle number concentration.
A. Khalkhali, S. Samareh Mousavi,
Volume 2, Issue 3 (7-2012)
Abstract

In order to reduce both the weight of vehicles and the damage of occupants in a crash event simultaneously, it is necessary to perform a multi-objective optimization of the automotive energy absorbing components. In this paper, axial impact crushing behavior of the aluminum foam-filled thin-walled tubes are studied by the finite element method using commercial software ABAQUS. Comparison of the present simulation results with the results of the experiments reported in the previous works indicated the validity of the numerical analyses. A meta-model based on the feed-forward artificial neural networks are then obtained for modeling of both the absorbed energy (E) and the peak crushing force (Fmax) with respect to design variables using those data obtained from the finite element modeling. Using such obtained neural network models, a modified multi-objective GA is used for the Pareto-based optimization of the aluminum foam-filled thinwalled tubes considering three conflicting objectives such as energy absorption, weight of structure, and peak crushing force.


M. Kazemi, M. Jooshani,
Volume 2, Issue 4 (10-2012)
Abstract

The suspension system of a vehicle is one of the most important parts which is involved in the process of vehicle designing. When a vehicle suspension system is designed, the evaluation of its performance against the road disturbances such as shocks and bumps are very important. The most commonly used systems consist of four hydraulic Jacks with mobility in vertical line with low speed and low exactitude. This paper offers a new mechanism for inspecting the suspension system of a vehicle using a parallel robot called Stewart. This robot is a special kind of parallel robots with capability of movements in different directions with high speed, accuracy and repeatability. In this paper the suspension system is evaluated on a quarter model of a simulated vehicle with control and guidance of Stewart robot using PID controller. The Stewart robot simulates the isolated and uneven bumps on a flat road in order to evaluate the given suspension system, and to investigate some criteria such as comforting of the passengers and remaining of the vehicle on the road. The results of the simulations show that the proposed method has a high accuracy, applicability and flexibility as well as simplicity, compared to currently used mechanisms.

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