High-performance Vehicle Research Articles

High-Performance Lithium Metal Negative Electrode with a Soft and Flowable Polymer Coating

The future development of low-cost, high-performance electric vehicles depends on the success of next-generation lithium-ion batteries with higher energy density. The lithium metal negative electrode is key to applying these new battery technologies. However, the problems of lithium dendrite growth and low Coulombic efficiency have proven to be difficult challenges to overcome. Fundamentally, these two issues stem from the instability of the solid electrolyte interphase (SEI) layer, which is easily damaged by the large volumetric changes during battery cycling. In this work, we show that when a highly viscoelastic polymer was applied to the lithium metal electrode, the morphology of the lithium deposition became significantly more uniform. At a high current density of 5 mA/cm2 we obtained a flat and dense lithium metal layer, and we observed stable cycling Coulombic efficiency of ∼97% maintained for more than 180 cycles at a current density of 1 mA/cm2.

Design and Fabrication of High Strength, High Modulus Polymer Reinforced Metal Matrix Composites for Light Weight Applications

Objectives: The present work reports the possible solution of using the high thermal stability polymer fibres with superior mechanical properties as that of, or, even better than metals for light weight applications like aerospace and automobile. Methods/Statistical Analysis: The PBO filament fibre was used as reinforcement. The PBO fibres were electroless copper coated to protect the polymer fibre from oxidation during processing and to improve the interfacial properties between the reinforcing polymer and the metal matrix. LM6 aluminium cast alloy was used as a matrix metal. The electroless copper coated PBO fibres preform were unidirectional placed inside a mould and infiltrated by molten liquid metal. Findings: After casting, it was found that the liquid melt could infiltrate only partially through the first layer of the fibre preform, and could not infiltrate further, which was evident from the infiltrated metal front. This was mainly because of the forced convective heat transfer made by the argon cover gas, which cools the molten metal front and thereby increases the surface tension of the advancing front. It was further noticed that some charring of the polymer fibres after two hours of casting, which reflects that, there was oxidation of polymer fibres after prolonged heating by the hot infiltrating metal front in absence of argon cover gas after first one hour of its use after casting. Application: The new material proposed for development could find applications in light weight high performance vehicles like aerospace and automobiles..

A new anti-skid control method for electric vehicles using the motor torque and the wheel acceleration with experimental verification

Driving electric vehicles by electric motors can result in many unique advantages for dynamic control of electric vehicles. With the superior fast and accurate torque control performance of electric motors, electric vehicles, in particular, can achieve higher levels of safety and handling performance. A simple, effective and efficient anti-skid control method specified for electric vehicles is proposed in this paper by considering the real-world resistance factors. This method is developed on the basis of sensing and regulating a newly defined parameter, namely the ratio of the drive motor torque to the angular acceleration of the wheels, both of which can be easily obtained for electric motors. The monotonic relationship between the slip ratio and the ratio of the drive motor torque to the angular acceleration of the wheels is proved under both acceleration conditions and deceleration conditions, by considering the real-world resistance factors. The simulations and the experimental results show that the ratio of the drive motor torque to the angular acceleration of the wheels can be efficiently used, instead of the slip ratio, in anti-skid control. The results indicate that electric vehicles can achieve high-performance vehicle motion control with more flexible and simplified configurations by using in-wheel electric motors.

Numerical Simulation Analysis of an Oversteer In-Wheel Small Electric Vehicle Integrated with Four-Wheel Drive and Independent Steering

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.

Efecto del rendimiento del combustible en la decisión de compra de vehículo

El artículo presenta los resultados de una investigación que se realizó con el propósito de estudiar el efecto del rendimiento del combustible en la adquisición de un vehículo nuevo. La metodología se basó en una encuesta de preferencias declaradas, en el contexto de un experimento de elección de dos alternativas no etiquetadas que se caracterizan por el costo del auto y el rendimiento del combustible. Con los datos acopiados se estimó un modelo Logit Multinomial, que permitió estudiar diferentes escenarios de elección. Se encontró que, en promedio, los individuos están dispuestos a pagar $1.020.000 por mejorar en 1 km/galón el rendimiento del combustible, este valor puede servir de referencia a la industria automotriz en el esfuerzo por producir vehículos de mayor rendimiento.

교통안전성을 고려한 고속도로 오르막차로 동적운영 알고리즘 개발

본 연구는 다양한 교통상황에서의 오르막차로의 안전성 측면을 고려하여 운영기준 수립 및 운영 알고리즘을 개발하고자 하였다. 교통량과 중차량 비율에 따른 시나리오를 설정하고, 미시적 교통류 시뮬레이션으로 구현하여 분석을 수행하였으며, 오르막차로 개폐여부에 따른 안전성을 평가하였다. 안전성을 평가하기 위하여 교통상충건수와 상충심각도를 평가지표(SSM:Surrogate Safety Measure)로 사용하였다. 분석결과, 서비스 수준이 낮고 중차량 비율이 증가할수록 교통상충건수가 증가하였으며, 서비스수준이 높고 중차량 비율이 증가할수록 상충 심각도가 높아짐을 보였다. 이를 바탕으로 교통 안전성 측면을 고려한 오르막차로 개 폐 기준 및 탄력적 운영을 위한 알고리즘을 제시하였다. 본 연구결과를 활용할 경우, 기존의 운영효율성 측면과 안전성측면 동시에 고려할 수 있는 효율적인 오르막차로 운영이 가능할 것이며, 교통사고 감소 효과도 기대할 수 있을 것이다. 또한 갓길차로, 공사구간관리 등 LCS 운영시 안전성 측면을 고려한 전략적 운영을 지원할 수 있을 것이다. Interest in freeway truck traffic has increased largely due to greater safety concerns regarding truck-related crashes. The negative interactions between slow-moving trucks and other vehicles are a primary cause of hazardous conditions, which lead to crashes with larger speed variations. To improve operational efficiency and safety, providing a climbing lane that separates slow-moving trucks from higher performance vehicles is frequently considered when upgrading geometrics. This study developed an operations strategy for freeway climbing lanes based on traffic conditions in real time. To consider traffic safety when designing a dynamic strategy to determine whether a climbing lane is closed or open, various factors, including the level of service (LOS) and the percentage of trucks, are investigated through microscopic simulations. A microscopic traffic simulator, VISSIM, was used to simulate freeway traffic streams and collect vehicle-maneuvering data. Additionally, an external application program interface, VISSIM's COM-interface, was used to implement the proposed climbing lane operations strategies. Surrogate safety measures (SSM), including the frequency of rear-end conflicts and, were used to quantitatively evaluate the traffic safety using an analysis of individual vehicle trajectories obtained from VISSIM simulations with various operations scenarios. It is expected that the proposed algorithm can be the backbone for operating the climbing lane in real time for safer traffic management.

Characterising the interaction of individual-wheel drives with traction by linear parameter-varying model: a method for analysing the role of traction in torsional vibrations in wheel drives and active damping

A model-based approach for characterising the interaction of individual-wheel drives with traction is contributed in this article. The primary aim is to investigate the influence of traction on torsional vibration behaviour in the drive train. The essence of this approach lies in reformulating the nonlinear traction behaviour into its differential form, which enables an analytical description of this interaction in its linear parameter-varying model equivalence. Analytical statements on the vibration behaviour for different driving scenarios are inferred from this model and validated with measurement samples from a high-performance electric road vehicle. Subsequent influences of traction on the performance of active damping of torsional vibrations are derived from this model.

포뮬러 형태의 자작자동차 설계 및 제작

Article history: A hand-made vehicle with a formula (VF-1) was designed and manufactured with the aim of realizing a lightweight and high-performance vehicle. The driver’s body weight and stiffness of the frame were considered. The vehicle was equipped with a one-cylinder Exiv 250 engine with intake manifold potting for realizing weight reduction, high performance, and low cost. The suspension system for the formula was designed through the analyses and tests of vehicle motion and equipment. In a steering system, anti-Ackerman geometry was introduced to increase the transverse force during cornering. A full electric paddle shift system was adopted to decrease the braking distance. For protection against the distortion and warping of the frame, tungsten inert gas (TIG) welding technology was used.

한국의 우주발사체 산업 발전을 위한 우주발사서비스 시장진입 전략 평가

국가위상 제고와 국내 발사체산업 발전에 따른 경제 발전을 위하여 우주발사서비스 시장진입은 필수적이다. 발사체 개발의 후발주자로써 시장에 효과적으로 진입하기 위해서는 시장의 트렌드를 정확하게 파악하고, 체계적인 시장진입전략을 수립하여야한다. 본 논문에서는 세계 우주발사서비스 시장의 3가지 핵심트렌드(고성능의 대형 우주발사체 수요 증가, 저가형 우주발사체 증가, Dual/Multi-Launch 증가)를 도출하고, 각 핵심트렌드에 대응하기 위한 전략의 우선순위를 쌍대비교분석법을 통해 평가하였다. 그 결과 모든 트렌드 하에서 발사체 신뢰성 확보 전략이 가장 중요하며, 고성능의 대형 우주발사체 수요 증가 트렌드 하에서는 정부 지원 전략이, 저가형 우주발사체 및 Dual/Multi-Launch 증가 트렌드 하에서는 가격 경쟁력 확보전략이 두 번째 우선순위를 보였다. This paper suggests the significant strategies and their priority to deal with space transportation market trends. First, market trends related with technical improvement and change in demand are analyzed by the literature research. The three key trends are obtained: 'Increasing Demand of High-Performance Launch Vehicles', 'Rising of Low-Price Launch Vehicles', and 'Rising of Dual/Multi-Launch'. And then, strategies for developing the launch vehicle industry in Korea are selected from several studies about commercialization of Korean launch vehicle. The strategies are evaluated by the experts through pairwise comparison matrix and the criteria for this process is how significantly does the strategy effect on the launch vehicle industry through market assessment. As a result, reliable order of priority among the strategies are obtained. Under the three key trends, strategy to enhance reliability is most important. And, strategy to have price competitiveness has secondary priority to deal with 'Rising of Low-Price Launch Vehicles' trend and 'Rising of Dual/Multi-Launch' trend. On the contrary, strategy of government's support is secondary under 'Increasing Demand of High-Performance Launch Vehicles' trend.

Extended Modeling of Vertical Axis Motion Dynamics of VTOL Vehicle

Development of a reliable high-performance multirotor unmanned aerial vehicle (UAV) requires an accurate and practical model of the vehicle dynamics. This paper describes the process and results of the dynamic modeling of an unmanned aerial platform known as quadrotor. To model a vehicle dynamics, elementary physical and aerodynamical principles has been employed. Parameter estimations, from a UAV design have been obtained through direct and indirect measurements. In addition to standard configuration of VTOL (Vertical Take-Off and Landing) platform, the amortized landing gear, modeled as spring-damper system, has been added. The resulting model has been implemented in a simulation environment under MATLABs toolbox, SIMULINK. Some numerical results are presented to illustrate response of the open loop system to specific commands.

Engineered Ionic Diffusion Layers to Increase Rate Capability of NCA Cathode with Larger Particle Sizes in Lithium-Ion Cells

Low cost, high energy and long cycle life Lithium-ion batteries are the technology of choice widespread implementation of high-performance electric vehicles (EVs). In spite of the strides technology has made, current high energy density solutions suffer from well understood and catastrophic degradation mechanisms that have prevented the full fruition of NCA cathode materials. There is growing evidence that the cathode surface is the initiation site of all the above mechanisms, motivating the use of larger particle sizes to minimize surface area and mitigate degradation. However, larger particle sizes decrease the overall rate of diffusion of lithium ions, causing a loss of activation of Li-rich phases and an increased loss of capacity at higher rates. Here we show that Al2O3 and TiO2 ALD coatings applied to NCA powder, completely covering active material particle surfaces, create a cathode artificial SEI layer which facilitates an improved Li-ion diffusion pathway, increasing the rate capability of NCA cathodes even with larger particle sizes. Electrochemical analyses showed increased rate capability in 95x64 mm pouch cells (~2.5Ah) with coated NCA compared to uncoated, and XRD and TEM were used to characterize the underlying favorable interactions of coatings with the cathode surface. XALT Energy’s integrated cell design and manufacturing makes 95x64 mm cell performance representative of large format (216x216 mm) production EV cells, demonstrating the validity and scalability of this approach.

Layered-to-Spinel Phase Transformations Inhibited By ALD Coatings on NMC Cathodes to Mitigate Voltage Fade in Lithium-Ion Cells

Low cost, high energy and long cycle life Lithium-ion batteries are the technology of choice widespread implementation of high-performance electric vehicles (EVs). In spite of the strides technology has made, current high energy density solutions suffer from well understood and catastrophic degradation mechanisms that have prevented to full fruition of lithium- and manganese-rich NMC cathode materials. Capacity, power, and voltage fade, excessive SEI growth, electrolyte oxidation, cathode dissolution, structural degradation, and phase transformations are only few of the mechanisms that have been identified. Layered-to-spinel phase transformations at high voltages (~4.8 V), are a main contributor to voltage fade in LMR-NMC-based batteries. Here we show that TiO2 and Al2O3 atomic layer deposition (ALD) coatings applied to NMC powder, conformally coating active material particle surfaces, create a cathode artificial SEI layer which alters and slows the chemical pathways for nucleation and propagation of layered-to-spinel phase transformations at high voltages. XRD, TEM, and magnetic susceptibility characterization of active materials before cycling and at end of cycle life in 95x64 mm pouch cells (~2.5Ah) showed decreased extent of phase transformation with coated NMC compared to uncoated. XALT Energy’s integrated cell design and manufacturing makes 95x64 mm cell performance representative of large format (216x216 mm) production EV cells, demonstrating the validity and scalability of this approach.

ELECTRO MECHANICAL SPLIT PAD DISC BRAKE USING SOLENOID VALVE

With the advent of new era came the high performance vehicles which runs at an average speed of 80 km/hr. Braking at higher speeds created problems like high brake shoe wear, false braking and loss of maneuverability. To cope up with the new situations, new braking systems needs to be developed, which are highly refined and automated. We have developed a system that is a solution to the current problem. The system is an amalgamation of electrical and mechanical aspects, hence giving the brakes dual functionality, thus increasing the service life and performance simultaneously.

HISTORY OF DEVELOPMENT OF SQUID-LIKE BIOMIMETIC UNDERWATER ROBOTS WITH UNDULATING SIDE FINS

The underwater robot is a basic tool to explore the unknown territories in the underwater region of the coastal areas and oceans, both from the scientific and industrial perspectives. With the aim of developing an efficient and environmentally friendly underwater robot, a Squid-like robot with two undulating side fins has been developing for many years by the authors' group in Osaka University, Japan. The high ambitious project started in 2002; from then different models have been developed to reach the goal of achieving a high-performance underwater vehicle. The body and propulsion system of the robot have been developed by following the swimming mechanism of flat-fishes that use undulating side fins, e.g. Squid, Stingray Cuttlefish and Manta. The Squid-robot is now in its fifth generation of development. In the present paper, the review of the development of models of the Squid-robot is presented. The development of the mechanical system and the control system of each model is described in brief. Some CFD computations and motion simulations of Model-4 are also discussed. The background of developing a new model and the updated features are stated for each model respectively. The future target of development of the robot is also pointed out. The objective of this paper is to provide relevant and useful information to the engineers involved in underwater vehicle design, and for those with an interest in the fast-growing area of biomimetic swimming robots.

High-performance on-road vehicle detection with non-biased cascade classifier by weight-balanced training

In this paper, we propose a cascade classifier for high-performance on-road vehicle detection. The proposed system deliberately selects constituent weak classifiers that are expected to show good performance in real detection environments. The weak classifiers selected at a cascade stage using AdaBoost are assessed for their effectiveness in vehicle detection. By applying the selected weak classifiers with their own confidence levels to another set of image samples, the system observes the resultant weights of those samples to assess the biasing of the selected weak classifiers. Once they are estimated as biased toward either positive or negative samples, the weak classifiers are discarded, and the selection process is restarted after adjusting the weights of the training samples. Experimental results show that a cascade classifier using weak classifiers selected by the proposed method has a higher detection performance.

Understanding the influence of traction on the Eigen behaviour of torsional vibrations in individual-wheel drives

Abstract This article presents a model-based analysis of the influence of traction on the Eigen behaviour of torsional vibrations in individual-wheel drives (IWDs) of a high-performance road vehicle. As a significant motivation, measurement samples from test drives are presented and representative vibration behaviours are highlighted. For the analysis, linearised models representing the interaction of an IWD with traction are utilised. The significance of the analysis results is demonstrated through comparisons with the measurement samples and corresponding interpretations.

Practical Flapping Mechanisms for 20 cm-span Micro Air Vehicles

In the body of research relevant to high-performance flapping micro air vehicles (MAV), development of light-weight, compact and energy-efficient flapping mechanisms occupies a position of primacy due to its direct impact on the flight performance and mission capability. Realization of such versatile flapping mechanism with additional ability of producing thrust levels that fulfill requirements of cruising forward flight and vertical take-off and landing (VTOL) conditions demand extensive design validation and performance evaluation. This paper presents a concerted approach for mechanism development of a 20 cm span flapping MAV through an iterative design process and synergistic fabrication options involving electrical-discharge-wire-cutting (EDWC) and injection molding. Dynamic characterization of each mechanism is done through high speed photography, power take-off measurement, wind tunnel testing and proof-of-concept test flights. The research outcome represents best-in-class mechanism for a 20 cm span flapping MAV with desirable performance features of extra-large flapping stroke up to 100°, minimal transverse vibrations and almost no phase lag between the wings.

Reliance on technical solutions to environmental problems: caution is needed.

The world is full of examples of unintended consequences. Many solutions to burgeoning problems, whether social or technological, are later found to have unintended side effects. Sometimes these are beneficial; more commonly, they are not, and can be serious enough to call into question the efficacy of the original solution. One key area for concern is with technological solutions to our many environmental challenges. Car travel exemplifies the mixed success of technological solutions to the environmental problems it generates. At least in the cities of the Organization for Economic Cooperation and Development (OECD) countries, urban air pollution from vehicles has been greatly reduced over the past half-century. Technical emission reduction innovations include unleaded petrol, progressively lower sulfur content fuels, and three-way catalytic converters. But other proposed innovations for solving both global oil depletion and climate change may fall short of their stated aims. Improving the fuel efficiency of all vehicles promises to cut both transport oil use and accompanying greenhouse gas emissions. However, although vehicle engine efficiency has made large gains, the on-road vehicle efficiency gains (in terms of vehicle-km per MJ) have been much more modest. Reasons include preferences for larger or higher-performance vehicles, and significant power requirements for auxiliaries such as air-conditioning, information and entertainment systems, and power steering. National transport oil use and CO2 emissions are also subject to the well-known rebound effect: vehicle efficiency improvements make travel cheaper per kilometer, encouraging more travel. Furthermore, most of the world’s population aspire to the car ownership levels of the OECD countries, so total transport oil use and CO2 emissions are still growing. This rebound effect is not the fault of the technology, but of our use of it. There is yet another reason for caution: technical advances are sometimes reversed as more information about unwanted effects accumulate. Such has been the case for leaded petrol. More recently, France is considering reversing its previous promotion of diesel-fueled cars. Although diesel cars are more efficient than petrol cars, concern is mounting over the health effects of diesel’s fine particulate releases. As another example, novel chemical compounds such as chlorofluorocarbons, once though as environmentally benign (having low reactivity, toxicity and boiling point), were later found to cause ozone layer depletion. We need to be especially cautious when dealing with global problems such as climate change. One important approach for climate change mitigation is reducing fossil fuel use through much greater use of renewable energy, particularly biomass. But a recent study

Electric vehicle side-slip control via electronic differential

An electronic differential for high-performance electric vehicles with independent driving motors is proposed in this paper. This electronic differential endows the electric vehicle with a close-to-zero vehicle side-slip angle. When vehicle side-slip vanishes, the heading direction of the vehicle coincides with the velocity direction of the mass centre. In addition to the side-slip angle, the yaw rate is driven towards an optimal value with the configuration of the simulated vehicle. The improvements in vehicle side-slip angle and yaw rate responses greatly enhance the stability and handling of the simulated electric vehicle. In this paper, the mathematical relationships between the vehicle dynamic states and the independent motor torques are revealed, based on which the proposed electronic differential controller is designed. Simulation results manifest that in various challenging steering scenarios, the proposed control method outperforms two common electronic differential control schemes in terms of vehicle side-slip angle and yaw rate responses.

High-Performance Vehicle Streams: Communication and Control Architecture

This paper presents the overall framework for high-performance vehicle streams that integrates the transportation and the communication layered architectures together. It shows the process in establishing an infrastructure for high-performance vehicles and the theoretical development and deployment of cooperative adaptive cruise control (CACC) for heterogeneous vehicles that is integrated with lateral control. The system is designed to be fault tolerant and uses the concept of subplatoons. Our framework is based on integrating a transportation layered architecture with the Wireless Access in Vehicular Environment (WAVE) communication protocol.