Modelling and controlling of car-following behavior in real traffic flow using ARMAX identification and Model Predictive Control

Nowadays, car following models, as the most popular microscopic traffic flow modeling, are increasingly being used by transportation experts to evaluate new Intelligent Transportation System (ITS) and Advanced Driver Assistance Systems (ADAS) applications. The control of car following is essential due to its safety and its operational efficiency. For this purpose, this paper builds a model of car following behavior based on ARMAX structure from a real traffic data set and presents a Model Predictive Control (MPC) controller. An important advantage of this type of control is its ability to cope with constraints on controls. Since safety and operational efficiency are constraints for car following, therefore we have recruited this type of controller in this study to deal with these constraints. Based on the relative distance and relative acceleration of each instant, the MPC predicts the future behavior of the leader vehicle (LV) and according to this behavior, the acceleration of the follower vehicle (FV) is controlled. The MPC tries to control this acceleration in a way to keep the relative distance at a safe region. To investigate the performance of the designed controller, the result of the system is compared with the behavior of human drivers with similar initial conditions. Also, some other test performances were accomplished to investigate other features such as robustness and the stability of the designed MPC. The simulation results show that the MPC controller has a behavior much safer than that of real drivers and it can provide a pleasant trip for passengers.     

Crashworthiness of chromium plated plastic radiator grille

The use of plastic in vehicle development has increased. In particular, a design trend has resulted in chromiumplated plastics being used in exterior panels. Recently, as the appearance has become more important in design, the plastic radiator grille has become larger, to where it can become the primary member when a front collision happens. The radiator grille should be designed with considerations of the geometric structure, such as delamination, and material characteristics, when plastics are plated with chromium. The enlarged grille has to pass regulations like FMVSS Part 581. Although the material property of plastic has been studied before, what seems to be lacking is study on the crashworthiness of plastic radiator grilles that are plated using chromium. In this paper, in order to evaluate the crashworthiness, tensile test and front collision analysis using finite element method are performed. Tensile test is conducted with 4 types of materials, and then material properties of chromium-plated plastics are obtained. Meanwhile radiator grille’s crashworthiness is evaluated using finite element analysis method. Analysis result is evaluated according to failure criterion. Through this study, method of the assessment of plastic radiator grille’s crashworthiness considered material properties of chromium plated plastics is proposed, and it can be predicted the delamination and the failure point of radiator grille at the design step.     

Topological analysis of powertrains for refuse-collecting vehicles based on real routes–Part II: Hybrid electric powertrain

In this two-part paper, a topological analysis of powertrains for refuse-collecting vehicles (RCVs) based on simulation of different architectures (internal combustion engine, hybrid electric, and hybrid hydraulic) on real routes is proposed. In this second part, three different hybrid electric powertrain architectures are proposed and modeled. These architectures are based on the use of fuel cells, ultracapacitors, and batteries. A calculation engine, which is specifically designed to estimate energy consumption, respecting the original performance as the original internal combustion engine (ICE), is presented and used for simulations and component sizing. Finally, the overall performance of the different architectures (hybrid hydraulic, taken from the first paper part, and hybrid electric, estimated in this second part) and control strategies are summarized in a fuel and energy consumption table. Based on this table, an analysis of the different architecture performance results is carried out. From this analysis, a technological evolution of these vehicles in the medium- and long terms is proposed.     

Two-port network based bilateral control of a steer-bywire system

Steer-by-wire (SBW) system which is characterized by variable steering feel, better active safety, unmanned drive, has been widely studied to realize a distinctive driving experience. Control strategy acts as a key part of SBW system to achieve the goals. In this paper, a control strategy by bilateral control structure for steer-by-wire system is proposed. To make SBW system has the same function of conventional steering systems, the controller is designed to realize desired tracking control and realistic road feel feedback. The control of position and torque for each actuator is taken as two ports for the control network. Based on different control loop, two kinds of bilateral control is investigated respectively. The hardwarein- the-loop experiment platform of SBW is developed by the reconfiguration of electric power steering system. The test results are compared to show the performance of different control loops.     

Application of rack type motor driven power steering control system for heavy vehicles

The Electric Power Steering (EPS) or Motor Driven Power Steering (MDPS) mechanism proves to be a bright prospect among passenger vehicles ensuring better vehicle safety and fuel economy. The car manufacturers are focusing on the production of Rack type EPS system (REPS). This paper describes the development of concurrent simulation technique using TruckSim and control strategy for analysing RMDPS control system with a dynamic vehicle system. A full Truck vehicle model interacting with RMDPS control algorithm was concurrently simulated on a sinusoidal steering input. The dynamic responses of vehicle chassis and steering system resulting were evaluated and compared with proving ground experimental data. The comparisons show reasonable agreement on steering wheel torque, lateral acceleration and yaw rate. This concurrent simulation research leads the possibility of RMDPS performance evaluation of Truck and Semi-bonnet cars.     

Idle speed controller based on active disturbance rejection control in diesel engines

This study proposes a design for an idle speed controller to compensate for varying engine load and friction torque in passenger car diesel engines. An active disturbance rejection control (ADRC) framework, comprised of a disturbance compensator and a feedback controller, is applied to an idle speed controller to compensate for disturbances such as engine load and friction torque. In addition, a feedforward compensator is designed into the ADRC framework to improve disturbance rejection performance. The proposed controller is validated by engine and vehicle experiments and the experiment results are compared with a commercial controller.     

BFRP加固损伤混凝土梁挠度计算方法

为了准确计算玄武岩纤维增强复合材料(BFRP) 加固损伤混凝土梁的挠度, 为BFRP加固损伤混凝土梁的设计与施工提供理论依据, 按照配筋率不同设计了11片试验梁进行试验, 每组试验梁设置不同的BFRP布加固量与加载方法。计算了各试验梁的荷载-挠度曲线, 分析了未加固梁、1层BFRP布加固梁、2层BFRP布加固梁在不同初始荷载下的挠度变化规律。给出了BFRP加固损伤混凝土梁跨中挠度的计算公式, 对比了挠度计算值与实测值。分析结果表明: BFRP加固混凝土梁的挠度受初始荷载和加固量的影响, 有初始荷载的加固梁挠度较无初始荷载的加固梁挠度增大30%~4%, 2层BFRP布加固梁的挠度较1层加固梁的挠度增大19%~2%, 计算挠度时需考虑BFRP布滞后应变的影响; 挠度计算值与实测值的最大差值平均为7.26 mm, 初始荷载小与配筋率高的试验梁挠度计算值与实测值较为接近, 可以用于实际工程计算。     

Applications of intuitionistic fuzzy set aggregation operators in transport multi-factor project evaluation

Abstract

An intuitionistic fuzzy set (IFS) is a generalisation of a fuzzy set characterised by a truth membership function and a false membership function. The former is a lower bound on the grade of membership of the evidence in favour of a particular element belonging to the set and the latter is a lower bound on the negation of that element belonging to the set derived from evidence against that element belonging to the set. A similar concept is a vague set, though vague sets have been shown to be identical to IFSs. In the context of project evaluation, an IFS may be used to represent the degree to which a project satisfies a criterion and the degree to which it does not. Aggregation of such IFSs has been considered in recent years to identify a best project in terms of several criteria or factors. A particular desirable way to aggregate IFS is in terms of an ordered weighted average (OWA) which can be expressed in different forms such as arithmetic and geometric. In an OWA operator, weights are applied to the position of an element in the aggregation. In addition, hybrid OWA operators may be developed to not only weight the position of elements in the aggregation but the element itself. An example is given relating to the Kuranda Range Road upgrade (Queensland, Australia) which is limited by grade, poor overtaking opportunities, poor horizontal alignment and other constraints and the road is expected to become increasingly congested over the next few years. A more flexible multi-factor decision method is used to identify a ‘best’ project from a set of four alternative projects.     

Exploring the effects of cooperative adaptive cruise control on highway traffic flow using microscopic traffic simulation

This paper examines the impact of having cooperative adaptive cruise control (CACC) embedded vehicles on traffic flow characteristics of a multilane highway system. The study identifies how CACC vehicles affect the dynamics of traffic flow on a complex network and reduce traffic congestion resulting from the acceleration/deceleration of the operating vehicles. An agent-based microscopic traffic simulation model (Flexible Agent-based Simulator of Traffic) is designed specifically to examine the impact of these intelligent vehicles on traffic flow. The flow rate of cars, the travel time spent, and other metrics indicating the evolution of traffic congestion throughout the lifecycle of the model are analyzed. Different CACC penetration levels are studied. The results indicate a better traffic flow performance and higher capacity in the case of CACC penetration compared to the scenario without CACC-embedded vehicles.     

An Institutional Analysis of Coordination in Liberalized Port-related Railway Chains: An Application to the Port of Rotterdam

Abstract

The European railway market has gone through a period of liberalization over the last two decades. The liberalization of the railway market has also affected port-related railway transport. Efficient port-related transport chains are key in the competition among ports, however providing this efficiency is to a large extent a coordination challenge. Many forms of coordination are needed to ensure that the railway chain operates efficiently, including the bundling of cargo, and good organization between railway companies, terminal operators and the infrastructure managers to realize an efficient use of assets. From the literature, it appears that less attention has been paid to the economic organization of port-related railway transport in general, and specifically in the new liberalized institutional environment. The goal of this paper is to come up with a framework to better understand the issue of coordination in port-related railway chains in a liberalized institutional environment. This paper presents a conceptual framework rooted in Transaction Cost Economics (TCE). Based on an in-depth study into coordination in liberalized container railway market at the Port of Rotterdam, empirical illustrations are used to adjust the TCE approach toward a dynamic model influenced by Douglas North's theory on economic and institutional change. Empirics from the port of Rotterdam show that new players have entered the railway market and their role has changed. This paper shows that coordination of railway operations has become more complex after the regime change. From a port perspective, liberalization does not lead to an optimal allocation of resources in a process that is highly operationally interdependent. In the liberalized environment, coordination arrangements are necessary to enable efficient coordination of railway operations in Rotterdam.