Search Results

This paper presents an evaluation of two different Vehicle to Infrastructure (V2I) applications, namely Red Light Violation Warning (RLVW) and Green Light Optimized Speed Advisory (GLOSA). The evaluation method is to first develop and use Hardware-in-the-Loop (HIL) simulator testing, followed by extension of the HIL testing to road testing using an experimental connected vehicle. The HIL simulator used in the testing is a state-of-the-art simulator that consists of the same hardware like the road side unit and traffic cabinet as is used in real intersections and allows testing of numerous different traffic and intersection geometry and timing scenarios realistically. First, the RLVW V2I algorithm is tested in the HIL simulator and then implemented in an On-Board-Unit (OBU) in our experimental vehicle and tested at real world intersections.

As the development of autonomous vehicles rapidly advances, the use of convoying/platooning becomes a more widely explored technology option for saving fuel and increasing the efficiency of traffic. In cooperative adaptive cruise control (CACC), the vehicles in a convoy follow each other under adaptive cruise control (ACC) that is augmented by the sharing of preceding vehicle acceleration through the vehicle to vehicle communication in a feedforward control path. In general, the desired velocity optimization for vehicles in the convoy is based on fuel economy optimization, rather than driveability. This paper is a preliminary study on the impact of the desired velocity profile on the driveability characteristics of a convoy of vehicles and the controller gain impact on the driveability. A simple low-level longitudinal model of the vehicle has been used along with a PD type cruise controller and a generic spacing policy for ACC/CACC.

The conventional hood with single material and stiffener structural form conceals some limitations on pedestrian protection and lightweight, not satisfying the requirements of structural strength, pedestrian protection and lightweight contradictory with each other at the same time. In this paper, a novel type hood is proposed to develop sandwich structure using architected cellular material with negative Poisson's ratio (NPR) configuration based on the decoupling thought of structural strength and energy absorption. Core-layer aluminum alloy material with NPR is used to meet the requirement of impact energy absorption, inner and outer skin using carbon fiber is selected to achieve high structural stiffness needed. This paper starts from the relations between geometric parameters of core-layer architected cellular material and mechanical properties, on this basis, the optimal geometric parameters can be expected using the multiobjective optimization method.

Nowadays, SC is recognized as a key element of hybrid energy storage system in modern energy supply chain for electric vehicles (EVs). Co9S8 as a promising electrode material attracts much attention for supercapacitor owing to its superior electrochemical capacity. However, its poor stability and electronic conductivity, which result in inferior cycling performance and rate capability, have seriously limited the practical application of Co9O8 in supercapacitors. In this article, Co9S8 nanoparticles were embedded in reduced graphene oxide (rGO) via a simple anneal approach as high efficient and stable electrodes for SCs. The Co9S8/rGO composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The Co9S8 nanoparticles were inserted tightly between the rGO layers due to strong intermolecular forces, preventing the cluster in reduction process of rGO from graphene oxide (GO).

This paper focuses on finding and analyzing the relevant parameters affecting traffic flow when autonomous vehicles are introduced for ride hailing applications and autonomous shuttles are introduced for circulator applications in geo-fenced urban areas. For this purpose, different scenarios have been created in traffic simulation software that model the different levels of autonomy, traffic density, routes, and other traffic elements. Similarly, software that specializes in vehicle dynamics, physical limitations, and vehicle control has been used to closely simulate realistic autonomous vehicle behavior under such scenarios. Different simulation tools for realistic autonomous vehicle simulation and traffic simulation have been merged together in this paper, creating a realistic simulator with Hardware-in-the-Loop (HiL), Traffic-in-the-Loop (TiL), and Software in-the-Loop (SiL) simulation capabilities.

The platooning of connected automated vehicles (CAV) possesses the significant potential of reducing energy consumption in the Intelligent Transportation System (ITS). Moreover, with the rapid development of eco-driving technology, vehicle platooning can further enhance the fuel efficiency by optimizing the efficiency of the powertrain. Since road grade is a main factor that affects the energy consumption of a vehicle, the estimation of the road grade with high accuracy is the key factor for a connected vehicle platoon to optimize energy consumption using vehicle-to-vehicle (V2V) communication. Commonly, the road grade is quantified by single consumer grade global positioning system (GPS) with the geodetic height data which is rough and in the meter-level, increasing the difficulty of precisely estimating the road grade.

Lane-changing is a typical traffic scene effecting on road traffic with high request for reliability, robustness and driving comfort to improve the road safety and transportation efficiency. The development of connected autonomous vehicles with V2V communication provide more advanced control strategies to research of lane-changing. Meanwhile, four-wheel steering is an effective way to improve flexibility of vehicle. The front and rear wheels rotate in opposite direction to reduce the turning radius to improve the servo agility operation at the low speed while those rotate in same direction to reduce the probability of the slip accident to improve the stability at the high speed. Hence, this paper established Four-Wheel-Steering(4WS) vehicle dynamic model and quasi real lane-changing scenes to analyze the motion constraints of the vehicles.

With the current drive of automotive and technology companies towards producing vehicles with higher levels of autonomy, it is inevitable that there will be an increasing number of SAE level L4-L5 autonomous vehicles (AVs) on roadways in the near future. Microscopic traffic simulators that simulate realistic traffic flow are crucial in studying, understanding and evaluating the fuel usage and mobility effects of having a higher number of autonomous vehicles (AVs) in traffic under realistic mixed traffic conditions including both autonomous and non-autonomous vehicles. In this paper, L4-L5 AVs with varying penetration rates in total traffic flow were simulated using the microscopic traffic simulator Vissim on urban, mixed and freeway roadways. The roadways used in these simulations were replicas of real roadways in and around Columbus, Ohio, including an AV shuttle routes in operation.

In recent years, the trend in the automotive industry has been favoring the reduction of fuel consumption in vehicles with the help of new and emerging technologies, such as Vehicle to Infrastructure (V2I), Vehicle to Vehicle (V2V) and Vehicle to Everything (V2X) communication and automated driving capability. As the world of transportation gets more and more connected through these technologies, the need to implement algorithms with V2I capability is amplified. In this paper, an algorithm called Pass at Green, utilizing V2I and vehicle longitudinal automation to modify the speed profile of a mid-size generic vehicle to decrease fuel consumption has been studied. Pass at Green (PaG) uses Signal Phase and Timing (SPaT) information acquired from upcoming traffic lights, which are the current phase of the upcoming traffic light and remaining time that the phase stays active.

This paper is on the design of a steer-by-wire system for a light commercial vehicle. A hardware-in-the-loop simulation test rig with the actual rack and pinion mechanism of the light commercial vehicle under study was built for this purpose. The steer-by-wire actuator can be placed on either the second pinion, the first pinion or both in the double pinion steering test system used. The hardware and geometry of the steering test rig are identical to the implementation of the steering system in the test vehicle. Unnecessary and expensive road testing is avoided with this approach as most problems are identified and solved in the hardware-in-the-loop simulation phase conducted in the laboratory where the steering subsystem and its controller exist as hardware and the rest of the vehicle exist as a software model running in real time. Hardware-in-the-loop simulation results show the effectiveness of the proposed controller design in tracking desired steering dynamics.

This paper presents the development of a transient active control (TABC) system for the Ford Transit Connect light commercial vehicle using semi active suspensions. The control objective is to improve the ride comfort and road holding together with achieving roll and pitch stability using four semi active suspension dampers, hence called transient active body control. Semi-active control algorithms such as sky-hook, ground-hook and hybrid are applied to each suspension while the roll and pitch stabilizing controllers are designed separately and interfere with the local semi-active controllers through a supervisory control algorithm, if necessary. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed technique.

There is an increasing trend in the worldwide automotive area towards developing hybrid electric vehicles as an intermediate solution to fulfill the new, more stringent pollutant emission level requirements set by governments. Conversion of braking energy into electrical energy stored in the battery through regenerative braking is an important aspect of hybrid electric vehicles that increases their fuel efficiency. This paper presents an electric regenerative power assisted brake algorithm developed to enhance energy efficiency of a front and rear wheel drive parallel hybrid electric commercial vehicle. The commercial vehicle used in this study is a second generation research prototype Ford Transit Parallel Hybrid Electric Van. The existing hydraulic brake system of this van was not altered for reasons of safety and reliability in the case of a problem with regenerative barking.

In a Hybrid Electric Vehicle (HEV), the main aim is to decrease the fuel consumption and emissions without significant loss of driving performance. Maximizing Overall Efficiency Strategy (MOES) algorithm, presented here, distributes the power demand among the available paths to the wheels to improve fuel economy. In MOES, the vehicle is considered as a system whose input and output are power capability of consumed fuel and actual power transferred to the road, respectively. The aim of the strategy is to maximize the overall efficiency of the vehicle determined as the ratio of output power to input power. The control algorithm and driver model were prepared within Simulink and used to drive the Carmaker model of the vehicle which is a Ford Transit hybrid electric research prototype van. Simulations were carried out in 3 modes of the vehicle; conventional mode, regenerative braking only mode and full MOES mode to analyze the role of optimization better.

Efficient use of oil resources has become the number one priority throughout the world. Vehicles, operating with alternative fuels like solar or hydrogen energy are still in the development phase. In this transition period, automotive companies are trying to produce more efficient road vehicles to reduce the negative impacts of the internal combustion engine. Advances in high-efficiency electrical machines (EM), high-specific energy/power units, lower-cost power electronics and embedded systems have promoted the use of EM solely and/or along with the internal combustion engine (ICE) to develop pollution-free vehicles. Due to the high cost of the energy storage units for a pure electric drive the current trend is towards the practice of hybrid electric vehicle (HEVs).

The paper presents the systematic approaches toward robust stability analysis of H2/H∞ controlled active suspension systems. The computational algorithms for the structured singular value μ are the main features of the work with an emphasis on quantifying the effects of uncertainty of the systems. The representation of vehicle parameter uncertainties is given in detail. The robustness test is subsequently done based on a quarter vehicle model. The results have showed that the H∞ controller is the best one on both robust stability and robust performance.

This research focuses on an integration of two optimal tracking controllers, the active suspension controller and the rear-wheel steering controller, with the objective of improving vehicle performances in terms of maneuverability and safety by enhancing road holding capability and lateral stability. The active suspension controller adjusts the vehicle roll angle and utilizes the vertical force at each active suspension to boost road holding capability. On the other hand, the rear-wheel steering controller adjusts rear steering angles to use lateral force at each ground-tire contact point and amplify the vehicle’s ability to follow the desired yaw rate and sideslip angle during cornering maneuvers. Though the active attitude motion and mass shifting of car body may seem to hold relationship with lateral stability, its ability to evenly distribute vertical tire forces benefits the rear-wheel steering controller by enhancing the road holding capability.

Gear transmission is widely used in mechanical transmission system and acts an important role in automotive industry. Manufacturing errors, assembly looseness, gear wear issues may result in gear backlash, noise and fatigue damage seriously affecting efficiency and service life of gear transmission. For gear transmission assembled, it is important to monitor the conditions of gear meshing and prevent the occurrence of dangerous situations. How to define the issues of gear tooth wear, misaligned bearing, gear eccentricity, backlash, and how to find faulty planetary gear sets and specific issues existing in gear transmission are meaningful and significant to ensure the quality of product. This paper starts from the analysis on gearing mechanism. Based on the behaviors represented by the issues, gear tooth wear, misaligned bearing, gear eccentricity and backlash are demonstrated and explained in detail.

It has been discussed in numerous prior studies that in-neutral coasting, or sailing, can accomplish considerable amount of fuel saving when properly used. The driving maneuver basically makes the vehicle sail in neutral gear when propulsion is unnecessary. By disengaging a clutch or shifting the gear to neutral, the vehicle may better utilize its kinetic energy by avoiding dragging from the engine side. This strategy has been carried over to series production recently in some of the vehicles on the market and has become one of the eco-mode features available in current vehicles. However, the duration of coasting must be long enough to attain more fuel economy benefit than Deceleration Fuel Cut-Off (DFCO) - which exists in all current vehicle powertrain controllers - can bring. Also, the transients during shifting back to drive gear can result in a drivability concern.

As one of the key technologies for EVs and HEVs, the design of their motors has been researched extensively, and some novel rotors of permanent magnet motor were proposed in order to improve torque capability, including average torque and torque ripple. Rotor structure selection of drive motor for various electric vehicles has been one of the key issues in matching of electric vehicle power system. Three motors are analyzed for providing visible insights to the contribution of different rotor structures to the torque characteristics, efficiency and extended speed range. First, an iterative comparative analysis of torque-speed characteristics with different flux linkage, d-axis inductance and rotor saliency ratio is performed for demonstrating the design principle. Then, the three motors are optimized by a genetic algorithm (GA) for further improving the torque characteristics.

This paper is on the application of electric power assisted steering and yaw stability control to a light commercial vehicle. An active steering system is developed and used for both purposes. Steering system and vehicle dynamics models are derived and built in Simulink and their response is compared to that of a validated Adams/Chassis model of the vehicle. A boost curve type electric power assisted steering controller and a yaw stability control system based on the model regulator steering controller are developed. Their performance is demonstrated through simulation results. A steering test rig built for safely developing steering controllers in a hardware-in-the-loop setting is introduced. Details of the experimental vehicle with active steering, built to test the concepts developed in the paper is also presented.