International Journal of Vehicular Technology
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Open Access journal
ISSN (Print) 1687-5702 - ISSN (Online) 1687-5710
Published by Hindawi [334 journals]
- Enhancing V2X Communication Based on a New Comb-Pilot Estimation Approach
Abstract: Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communication systems, known as V2X technologies, have increasingly attracted attention in current research on road safety and traffic ergonomics. The performance evaluation of these communication systems is an important step before their potential integration and use in real systems. V2X communications are based on the IEEE 802.11p standard also known as Wireless Access in Vehicular Environment (WAVE). V2X can affect human life; therefore a deep study related to V2X performance evaluation should be done in order to be sure about the system reliability. In this context, we have elaborated a deep study related to the effect of transmission range on V2X communications by considering the terminal mobility. First, we have evaluated the performance of the PHY layer on the IEEE 802.11p using simulation. Secondly, we have conducted real case measurements using the Arada LocoMate Transmission system. The obtained results shows the necessity to optimize the quality of transmission in V2X communications. Consequently, we propose in this paper a new comb-pilot technique to enhance the quality of Orthogonal Frequency Division Multiplexing (OFDM) transmission. Our proposal consists in two new uses of the pilot subcarrier estimation technique in order to decrease the elevated bit error rate (BER). The quality of transmission (QoT) is first evaluated relating to the pilot symbol rearranged positions. Second, we proposed to optimize the QoT by adding two supplementary pilot symbols as it can offer better channel estimation results. Based on the performance evaluation of our proposal, it is confirmed that both of rearrangement and the adding of the pilot patterns lead to performance enhancement compared to baseline model (standardized one).
PubDate: Sun, 18 Sep 2016 09:34:22 +000
- Numerical Simulation Analysis of an Oversteer In-Wheel Small Electric
Vehicle Integrated with Four-Wheel Drive and Independent Steering
Abstract: Similar to conventional vehicle, most in-wheel small EVs that exist today are designed with understeer (US) characteristic. They are safer on the road but possess poor cornering performance. With recent in-wheel motor and steer-by wire technology, high cornering performance vehicle does not limit to sport or racing cars. We believe that oversteer (OS) design approach for in-wheel small EV can increase the steering performance of the vehicle. However, one disadvantage is that OS vehicle has a stability limit velocity. In this paper, we proposed a Four-Wheel Drive and Independent Steering (4WDIS) for in-wheel small EV with OS characteristic. The aim of implementing 4WDIS is to develop a high steer controllability and stability of the EV at any velocity. This paper analyses the performance of OS in-wheel small EV with 4WDIS by using numerical simulation. Two cornering conditions were simulated which are (1) steady-state cornering at below critical velocity and (2) steady-state cornering over critical velocity. The objective of the simulation is to understand the behavior of OS in-wheel small EV and the advantages of implementing the 4WDIS. The results show that an in-wheel small EV can achieve high cornering performance at low speed while maintaining stability at high speed.
PubDate: Thu, 30 Jun 2016 13:05:49 +000
- Modeling, Validation, and Control of Electronically Actuated Pitman Arm
Steering for Armored Vehicle
Abstract: In this study, 2 DOF mathematical models of Pitman arm steering system are derived using Newton’s law of motion and modeled in MATLAB/SIMULINK software. The developed steering model is included with a DC motor model which is directly attached to the steering column. The Pitman arm steering model is then validated with actual Pitman arm steering test rig using various lateral inputs such as double lane change, step steer, and slalom test. Meanwhile, a position tracking control method has been used in order to evaluate the effectiveness of the validated model to be implemented in active safety system of a heavy vehicle. The similar method has been used to test the actual Pitman arm steering mechanism using hardware-in-the-loop simulation (HILS) technique. Additional friction compensation is added in the HILS technique in order to minimize the frictional effects that occur in the mechanical configuration of the DC motor and Pitman arm steering. The performance of the electronically actuated Pitman arm steering system can be used to develop a firing-on-the-move actuator (FOMA) for an armored vehicle. The FOMA can be used as an active safety system to reject unwanted yaw motion due to the firing force.
PubDate: Thu, 14 Apr 2016 08:33:27 +000
- Retracted: Managing DSRC and WAVE Standards Operations in a V2V Scenario
PubDate: Thu, 24 Mar 2016 07:19:44 +000
- Energy Management Strategy Implementation for Hybrid Electric Vehicles
Abstract: To reduce apace extraction of natural resources, to plummet the toxic emissions, and to increase the fuel economy for road transportation, hybrid vehicles are found to be promising. Hybrid vehicles use batteries and engine to propel the vehicle which minimizes dependence on liquid fuels. Battery is an important component of hybrid vehicles and is mainly characterized by its state of charge level. Here a modified state of charge estimation algorithm is applied, which includes not only coulomb counting but also open circuit voltage, weighting factor, and correction factor to track the run time state of charge efficiently. Further, presence of battery and engine together needs a prevailing power split scheme for their efficient utilization. In this paper, a fuel efficient energy management strategy for power-split hybrid electric vehicle using modified state of charge estimation method is developed. Here, the optimal values of various governing parameters are firstly computed with genetic algorithm and then fed to Pontryagin’s minimum principle to decide the threshold power at which engine is turned on. This process makes the proposed method robust and provides better chance to improve the fuel efficiency. Engine efficient operating region is identified to operate vehicle in efficient regions and reduce fuel consumption.
PubDate: Sun, 21 Feb 2016 16:47:59 +000
- Application of Genetic Algorithms for Driverless Subway Train Energy
Abstract: After an introduction on the basic aspects of electric railway transports, focusing mainly on driverless subways and their related automation systems (ATC, ATP, and ATO), a technique for energy optimization of the train movement through their control using genetic algorithms will be presented. Genetic algorithms are a heuristic search and iterative stochastic method used in computing to find exact or approximate solutions to optimization problems. This optimization process has been calculated and tested on a real subway line in Milan through the implementation of a dedicated Matlab code. The so-defined algorithm provides the optimization of the trains movement through a coast control table created by the use of a genetic algorithm that minimizes the energy consumption and the train scheduled time. The obtained results suggest that the method is promising in minimizing the energy consumption of the electric trains.
PubDate: Mon, 15 Feb 2016 14:35:28 +000
- Increasing the Cruise Range and Reducing the Capital Cost of Electric
Vehicles by Integrating Auxiliary Unit with the Traction Drive
Abstract: Poor cruise performance of Electric Vehicles (EVs) continues to be the primary reason that impends their market penetration. Adding more battery to extend the cruise range is not a viable solution as it increases the structural weight and capital cost of the EV. Simulations identified that a vehicle spends on average 15% of its total time in braking, signifying an immense potential of the utilization of regenerative braking mechanism. Based on the analysis, a 3 kW auxiliary electrical unit coupled with the traction drive during braking events increases the recoverable energy by 8.4%. In addition, the simulation revealed that, on average, the energy drawn from the battery is reduced by 3.2% when traction drive is integrated with the air-conditioning compressor (an auxiliary electrical load). A practical design solution of the integrated unit is also included in the paper. Based on the findings, it is evident that the integration of an auxiliary unit with the traction drive results in enhancing the energy capturing capacity of the regenerative braking mechanism and decreases the power consumed from the battery. Further, the integrated unit boosts other advantages such as reduced material cost, improved reliability, and a compact and lightweight design.
PubDate: Wed, 10 Feb 2016 14:08:46 +000
- Simple Simulated Propagation Modeling and Experimentation within and
around Buildings at 2700 MHz
Abstract: There is a growing interest in understanding wave behavior in urban and suburban environment for 5th generation broadband applications. With the advent of using broadband technologies in buildings, office space and vehicle have become a necessity on a large scale. Models, predictions, and calculations for in-building, within a vehicle or near a reflective object with microscale details, are becoming highly classified in a competitive telecom environment. This paper provides an improved understanding of signal strength behavior within suburban residences with predictions prequalified using a vehicular scanner. Supporting predictions are provided by a ray tracing algorithm developed for dissertation. Results indicate signal strength variation of more than 50 dB from “strong signal” locations such as room centers and far corners to “weak signal” locations where shadowing and tunneling effects are evident. Based on this unique classification a scheme is proposed which indicates that specular scattering provides the major signal energy at more than 70% of the locations within the residences. Finally, an observed rake stabilizing effect is attributed to the proximity of strong scatterers.
PubDate: Mon, 08 Feb 2016 09:23:03 +000
- A Modified Hybrid III 6-Year-Old Dummy Head Model for Lateral Impact
Abstract: Hybrid III six-year-old (6YO) child dummy head model was developed and validated for frontal impact assessment according to the specifications contained in Code of Federal Regulations, Title 49, Part 572.122, Subpart N by Livermore Software Technology Corporation (LSTC). This work is aimed at improving biofidelity of the head for frontal impact and also extending its application to lateral impact assessment by modifying the head skin viscoelastic properties and validating the head response using the scaled nine-year-old (9YO) child cadaver head response recently published in the literature. The modified head model was validated for two drop heights for frontal, right, and left parietal impact locations. Peak resultant acceleration of the modified head model appeared to have good correlation with scaled 9YO child cadaver head response for frontal impact on dropping from 302 mm height and fair correlation with 12.3% difference for 151 mm drop height. Right parietal peak resultant acceleration values correlate well with scaled 9YO head experimental data for 153 mm drop height, while fair correlation with 16.4% difference was noticed for 302 mm drop height. Left parietal, however, shows low biofidelity for the two drop heights as the difference in head acceleration response was within 30%. The modified head model could therefore be used to estimate injuries in vehicle crash for head parietal impact locations which cannot be measured by the current hybrid III dummy head model.
PubDate: Sun, 31 Jan 2016 14:17:08 +000
- Modelling and Simulation of ERTMS for Current and Future Mobile
Abstract: Nowadays, train control in-lab simulation tools play a crucial role in reducing extensive and expensive on-site railway testing activities. In this paper, we present our contribution in this arena by detailing the internals of our European Railway Train Management System in-lab demonstrator. This demonstrator is built over a general-purpose simulation framework, Riverbed Modeler, previously Opnet Modeler. Our framework models both ERTMS subsystems, the Automatic Train Protection application layer based on movement authority message exchange and the telecommunication subsystem based on GSM-R communication technology. We provide detailed information on our modelling strategy. We also validate our simulation framework with real trace data. To conclude, under current industry migration scenario from GSM-R legacy obsolescence to IP-based heterogeneous technologies, our simulation framework represents a singular tool to railway operators. As an example, we present the assessment of related performance indicators for a specific railway network using a candidate replacement technology, LTE, versus current legacy technology. To the best of our knowledge, there is no similar initiative able to measure the impact of the telecommunication subsystem in the railway network availability.
PubDate: Thu, 17 Dec 2015 12:22:26 +000
- Rate Request Sequenced Bit Loading Secondary User Reallocation Algorithm
for DMT Systems in Cognitive Radio
Abstract: A rate request sequenced bit loading reallocation algorithm is proposed. The spectral holes detected by spectrum sensing (SS) in cognitive radio (CR) are used by secondary users. This algorithm is applicable to Discrete Multitone (DMT) systems for secondary user reallocation. DMT systems support different modulation on different subchannels according to Signal-to-Noise Ratio (SNR). The maximum bits and power that can be allocated to each subband is determined depending on the channel state information (CSI) and secondary user modulation scheme. The spectral holes or free subbands are allocated to secondary users depending on the user rate request and subchannel capacity. A comparison is done between random rate request and sequenced rate request of secondary user for subchannel allocation. Through simulations it is observed that with sequenced rate request higher spectral efficiency is achieved with reduced complexity.
PubDate: Thu, 10 Dec 2015 07:36:31 +000
- Power Flows and Efficiency of Output Compound e-CVT
Abstract: Hybridization is the most promising vehicular technology to get significant improvements of the vehicle efficiency and performance in the short-term. Mechanical transmissions for hybrid vehicles are very often multiple modes transmission, which permit improving the performance in different working conditions. In this context, optimal design and control of these transmissions are a key point to improve the performance of the vehicles, and mathematical models which supports the design can play an important role in this field. In this work, an approach for evaluating the performance of Output Compound Split e-CVT (electric Continuously Variable Transmission) in steady-state is proposed. This approach, in addition to a kinematic analysis of the device, leads to the calculation of the internal power circulation modes and the efficiency of the device in different working conditions.
PubDate: Thu, 01 Oct 2015 12:06:08 +000
- New Method of Car Body Panel External Straightening: Tools of
Abstract: Recently repair and recovery vehicle body operations become more and more popular. A special place here is taken by equipment that provides performance of given repair operations. The most interesting things are methods for recovery of car body panels that allow the straightening without disassembling of car body panels and damaging of existing protective coating. Now, there are several technologies for repair and recovery of car body panels without their disassembly and dismantling. The most perspective is magnetic-pulse technology of external noncontact straightening. Basics of magnetic-pulse attraction, both ferromagnetic and nonferromagnetic thin-walled sheet metal, are explored. Inductor system calculation models of magnetic-pulse straightening tools are presented. Final analytical expressions for excited efforts calculation in the tools under consideration are introduced. According to the obtained analytical expressions, numerical evaluations of excited forces were executed. The volumetric epures of the attractive force radial distributions for different types of inductors were built. The practical testing of magnetic-pulse straightening with research tools is given. Using the results of the calculations we can create effective tools for an external magnetic-pulse straightening of car body panels.
PubDate: Sun, 26 Jul 2015 14:09:11 +000
- Development of Estimation Force Feedback Torque Control Algorithm for
Driver Steering Feel in Vehicle Steer by Wire System: Hardware in the Loop
Abstract: In conventional steering system, a feedback torque is produced from the contact between tire and road surface and its flows through mechanical column shaft directly to driver. This allows the driver to sense the steering feel during driving. However, in steer by wire (SBW) system, the elimination of the mechanical column shaft requires the system to generate the feedback torque which should produce similar performance with conventional steering system. Therefore, this paper proposes a control algorithm to create the force feedback torque for SBW system. The direct current measurement approach is used to estimate torque at the steering wheel and front axle motor as elements to the feedback torque, while, adding the compensation torque for a realistic feedback torque. The gain scheduling with a linear quadratic regulator controller is used to control the feedback torque and to vary a steering feel gain. To investigate the effectiveness of the proposed algorithm, a real-time hardware in the loop (HIL) methodology is developed using Matlab XPC target toolbox. The results show that the proposed algorithm is able to generate the feedback torque similar to EPS steering system. Furthermore, the compensation torque is able to improve the steering feel and stabilize the system.
PubDate: Sun, 31 May 2015 13:36:45 +000
- Channel Impulse Response Estimation in IEEE 802.11p via Data Fusion and
Abstract: Tracking the channel impulse response in systems based on the IEEE 802.11p standard, the most widely accepted standard for the physical layer in vehicular area networks (VANETs), is still an open research topic. In this paper we aim to improve previously proposed channel estimators by utilizing data aided algorithm that includes the channel decoding to enhance the quality of the estimated data. Moreover we propose a novel technique that exploits information provided by external sensors like GPS or speedometer, usually present in vehicles. The algorithm proposed so far has been analyzed in non-line-of-sight link conditions; in this paper we present an analysis of performances in the line-of-sight condition as well. Simulations show that both proposals give considerable improvements in terms of packet error rate and channel estimation error in the highway scenario which is surely the most stressing environment for the channel response tracker.
PubDate: Mon, 30 Mar 2015 13:34:47 +000
- Link Reliability Based Greedy Perimeter Stateless Routing for Vehicular Ad
Abstract: We propose an enhancement for the well-known greedy perimeter stateless routing (GPSR) protocol for vehicular ad hoc networks (VANETs), which exploits information about link reliability when one-hop vehicles are chosen for forwarding a data packet. In the proposed modified routing scheme, a tagged vehicle will select its one-hop forwarding vehicle based on reliability of the corresponding communication link. We define link reliability as the probability that a direct link among a pair of neighbour vehicles will remain alive for a finite time interval. We present a model for computing link reliability and use this model for the design of reliability based GPSR. The proposed protocol ensures that links with reliability factor greater than a given threshold alone are selected, when constructing a route from source to destination. The modified routing scheme shows significant improvement over the conventional GPSR protocol in terms of packet delivery ratio and throughput. We provide simulation results to justify the claim.
PubDate: Wed, 25 Mar 2015 06:57:28 +000
- Design of Commute Carpooling Based on Fixed Time and Routes
Abstract: Although the private carpooling market of China has grown rapidly, it has been embarrassed by problems such as obstructed information, disordered expense, and frequent crimes currently. In this paper, a commute carpooling program based on fixed time and routes is designed and corresponding carpooling information platform is built to realize information retrieval, information matching, and mutual selection and evaluation. We have practiced the program in Huaian, China, and then evaluated it using the improved time-expense impedance model and VISSIM simulation system. The result shows that the carpooling program can reduce 65%~86% of the time-expense impedance and optimize some network parameters up to 20%~40%. Since it will help in reducing the travel time and cost greatly, improving safety and economy during carpooling, and easing the traffic congestion, it is a worthy carpooling mode to be extended in China.
PubDate: Wed, 31 Dec 2014 11:19:09 +000
- Traction Control of Electric Vehicles Using Sliding-Mode Controller with
Tractive Force Observer
Abstract: Traction control is an important element in modern vehicles to enhance drive efficiency, safety, and stability. Traction is produced by friction between tire and road, which is a nonlinear function of wheel slip. In this paper, a sliding-mode control approach is used to design a robust traction controller. The control objective is to operate vehicles such that a desired wheel slip ratio is achieved. A nonlinearity observer is employed to estimate tire tractive forces, which are used in the control law. Simulation and experimental results have illustrated the success of the proposed observer-based controller.
PubDate: Sun, 21 Dec 2014 06:26:53 +000
- A Review of Optimal Energy Management Strategies for Hybrid Electric
Abstract: Presence of an alternative energy source along with the Internal Combustion Engine (ICE) in Hybrid Electric Vehicles (HEVs) appeals for optimal power split between them for minimum fuel consumption and maximum power utilization. Hence HEVs provide better fuel economy compared to ICE based vehicles/conventional vehicle. Energy management strategies are the algorithms that decide the power split between engine and motor in order to improve the fuel economy and optimize the performance of HEVs. This paper describes various energy management strategies available in the literature. A lot of research work has been conducted for energy optimization and the same is extended for Plug-in Hybrid Electric Vehicles (PHEVs). This paper concentrates on the battery powered hybrid vehicles. Numerous methods are introduced in the literature and based on these, several control strategies are proposed. These control strategies are summarized here in a coherent framework. This paper will serve as a ready reference for the researchers working in the area of energy optimization of hybrid vehicles.
PubDate: Tue, 18 Nov 2014 08:47:26 +000
- Neck Moment Characterization of Restrained Child Occupant at Realistic
Nontest Standard Higher Impact Speed of 32.2 km/h
Abstract: The effects of bullet vehicle crash impact angle, child restraint system design, and restraint harness slack at side impact speed of 32.2 km/h (20 mph) on moments sustained at the neck by a three-year-old child are investigated. Mathematical models are built using the response surface method based on simulation results whereby good fitness is achieved. The singular and cross interactive effect of each predictor on the neck moment are analyzed. The number of significant parameters affecting the neck moment is shown to be the largest for wide impact angles and the impact angle parameter is largely revealed to be the most sensitive. An ideal safe range for low neck moment has been established to be within angles 45° and 65°. It is further shown that the nature of all parameters effect on the neck moment is highly dependent on the impact angle range.
PubDate: Thu, 11 Sep 2014 08:10:17 +000
- Handover Performance over a Coordinated Contiguous Carrier Aggregation
Deployment Scenario in the LTE-Advanced System
Abstract: Although various carrier aggregation deployment scenarios (CADSs) have been introduced in the LTE-Advanced system, issues related to insufficient eNB coverage that leads to low throughput and high drop call have yet to be solved. This paper proposes a new deployment scenario called coordinated contiguous-CADS (CC-CADS), which utilizes two-component carriers (CCs) that operate on two frequencies located in a contiguous band. Each CC antenna is directed to a cell boundary of the other CC. The handover performance of users with various mobility speeds under CC-CADS has been investigated and compared with various deployment scenarios proposed by 3GPP. Simulation results show that the received signal reference power (RSRP) enhancement and performed handover, ping-pong, drop call, and outage probabilities reductions in CC-CADS outperformed the 3GPP’s CADSs, thus leading to reduced interruption time, improved spectral efficiency, and seamless handover.
PubDate: Sun, 31 Aug 2014 12:11:34 +000
- Driver’s Fatigue Detection Based on Yawning Extraction
Abstract: The increasing number of traffic accidents is principally caused by fatigue. In fact, the fatigue presentsa real danger on road since it reduces driver capacity to react and analyze information. In this paper we propose an efficient and nonintrusive system for monitoring driver fatigue using yawning extraction. The proposed scheme uses face extraction based support vector machine (SVM) and a new approach for mouth detection, based on circular Hough transform (CHT), applied on mouth extracted regions. Our system does not require any training data at any step or special cameras. Some experimental results showing system performance are reported. These experiments are applied over real video sequences acquired by low cost web camera and recorded in various lighting conditions.
PubDate: Wed, 06 Aug 2014 00:00:00 +000
- Autonomous, Distributed Parking Lot Vacancy Management Using Intervehicle
Abstract: We have developed a method of managing vacancy information of a large parking lot in a distributed manner using only intervehicle communication. A group of parking spaces is defined as a cluster. Vacancy information of a cluster is managed by a vehicle in it. This vehicle is called a cluster head. The proposed method generates a communication path topology between cluster heads. The topology is a tree structure with the cluster head of the cluster nearest to the parking lot entrance as the root node. Cluster heads are ranked in order of the number of vacant spaces and the distance to the shop entrance. The vehicle entering the parking lot collects vacancy information of clusters. This information is transmitted along the tree structure from the lowest ranking cluster head. We have developed a simulation model for a parking lot that can accommodate nearly 1,000 vehicles and used it to evaluate the proposed method. We have confirmed that the proposed method generates less communication traffic and enables the vehicle entering a parking lot to collect vacancy information about the area near the shop entrance with a higher probability and in a shorter time.
PubDate: Mon, 21 Jul 2014 08:00:01 +000
- A Probabilistic Analysis of Path Duration Using Routing Protocol in VANETs
Abstract: In recent years, various routing metrics such as throughput, end-to-end delay, packet delivery ratio, path duration, and so forth have been used to evaluate the performance of routing protocols in VANETs. Among these routing metrics, path duration is one of the most influential metrics. Highly mobile vehicles cause frequent topology change in vehicular network environment that ultimately affects the path duration. In this paper, we have derived a mathematical model to estimate path duration using border node-based most forward progress within radius (B-MFR), a position based routing protocol. The mathematical model for estimation of path duration consists of probability of finding next-hop node in forwarding region, estimation of expected number of hops, probability distribution of velocity of nodes, and link duration between each intermediate pair of nodes. The analytical results for the path duration estimation model have been obtained using MATLAB. The model for path duration estimation has been simulated in NS2. Each of the analytical results has been verified through respective simulation results. The result analysis clearly reveals that path duration increases with the increase in transmission range and node density and decreases with the increase in the number of hops in the path and velocity of the nodes.
PubDate: Thu, 17 Jul 2014 11:45:51 +000
- A Review of Active Yaw Control System for Vehicle Handling and Stability
Abstract: Yaw stability control system plays a significant role in vehicle lateral dynamics in order to improve the vehicle handling and stability performances. However, not many researches have been focused on the transient performances improvement of vehicle yaw rate and sideslip tracking control. This paper reviews the vital elements for control system design of an active yaw stability control system; the vehicle dynamic models, control objectives, active chassis control, and control strategies with the focus on identifying suitable criteria for improved transient performances. Each element is discussed and compared in terms of their underlying theory, strengths, weaknesses, and applicability. Based on this, we conclude that the sliding mode control with nonlinear sliding surface based on composite nonlinear feedback is a potential control strategy for improving the transient performances of yaw rate and sideslip tracking control.
PubDate: Thu, 12 Jun 2014 09:25:19 +000
- Nonlinear Controllers for a Light-Weighted All-Electric Vehicle Using
Chebyshev Neural Network
Abstract: Two nonlinear controllers are proposed for a light-weighted all-electric vehicle: Chebyshev neural network based backstepping controller and Chebyshev neural network based optimal adaptive controller. The electric vehicle (EV) is driven by DC motor. Both the controllers use Chebyshev neural network (CNN) to estimate the unknown nonlinearities. The unknown nonlinearities arise as it is not possible to precisely model the dynamics of an EV. Mass of passengers, resistance in the armature winding of the DC motor, aerodynamic drag coefficient and rolling resistance coefficient are assumed to be varying with time. The learning algorithms are derived from Lyapunov stability analysis, so that system-tracking stability and error convergence can be assured in the closed-loop system. The control algorithms for the EV system are developed and a driving cycle test is performed to test the control performance. The effectiveness of the proposed controllers is shown through simulation results.
PubDate: Tue, 22 Apr 2014 00:00:00 +000
- Dynamic Analysis and Design Optimization of Series Hydraulic Hybrid System
through Power Bond Graph Approach
Abstract: The availability of natural gas and crude oil resources has been declining over the years. In automobile sector, the consumption of crude oil is 63% of total crude oil production in the world. Hence, automobile industries are placing more emphasis on energy efficient hydraulic hybrid systems, which can replace their conventional transmission systems. Series hydraulic hybrid system (SHHS) is a multidomain mechatronics system with two distinct power sources that includes prime mover and hydropneumatic accumulator. It replaces the conventional transmission system to drive the vehicle. The sizing of the subsystems in SHHS plays a major role in improving the energy efficiency of the vehicle. In this paper, a power bond graph approach is used to model the dynamics of the SHHS. The obtained simulation results indicate the energy flow during various modes of operations. It also includes the dynamic response of hydropneumatic accumulator, prime mover, and system output speed. Further, design optimization of the system is carried out to optimize the process parameters for maximizing the system energy efficiency. This leads to increase in fuel economy and environmentally friendly vehicle.
PubDate: Tue, 01 Apr 2014 14:18:17 +000
- Stability Control of Vehicle Emergency Braking with Tire Blowout
Abstract: For the stability control and slowing down the vehicle to a safe speed after tire failure, an emergency automatic braking system with independent intellectual property is developed. After the system has received a signal of tire blowout, the automatic braking mode of the vehicle is determined according to the position of the failure tire and the motion state of vehicle, and a control strategy for resisting tire blowout additional yaw torque and deceleration is designed to slow down vehicle to a safe speed in an expected trajectory. The simulating test system is also designed, and the testing results show that the vehicle can be quickly stabilized and kept in the original track after tire blowout with the emergency braking system described in the paper.
PubDate: Tue, 11 Mar 2014 09:29:36 +000
- Broadcasting in Connected and Fragmented Vehicular Ad Hoc Networks
Abstract: This paper starts with an overview of vehicular ad hoc networks (VANETs) and their characteristics. Then this paper reviews diverse applications of VANETs and the requirements of these applications. In addition it reviews VANETs standards, different broadcasting presented in a variety of studies, and also associated issues with data dissemination in connected and fragmented vehicular networks to solve broadcast storm problem and temporary disconnected VANETs. The discussion will be about the encountered challenges and presented solutions with respect to the related issues, based on the literature and strength and weakness of each protocol.
PubDate: Sun, 09 Mar 2014 09:56:17 +000
- Distributed Algorithm for Constructing Efficient Tree Topology for Message
Dissemination in Vehicular Networks
Abstract: Vehicular ad hoc network is an ad hoc network constituted among moving vehicles that have wireless dedicated short range communication (DSRC) devices in order to provide ubiquitous connectivity even if the road-side infrastructure is unavailable. Message dissemination in vehicular ad hoc networks is necessary for exchanging information about prevailing traffic information, so that the vehicles can take alternate routes to avoid traffic jam. A major challenge in broadcast protocols is that they result in flooding of messages that reduce the speed of dissemination due to collision. Dissemination of messages using tree topology reduces the number of rebroadcasts. Dynamicity Aware Graph Relabeling System model provides a framework to construct spanning tree in mobile wireless network. In this paper, we propose a new distributed algorithm for constructing an arbitrary spanning tree based on Dynamicity Aware Graph Relabeling System model, which develops a maximum leaf spanning tree in order to reduce the number of rebroadcasts and dissemination time. Our simulation results prove that the number of vehicles rebroadcasting the message is curtailed to 15% and the dissemination time required to achieve 100% reachability is curtailed by 10% under average vehicle density.
PubDate: Thu, 20 Feb 2014 07:21:17 +000