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An integrated automatic driving system consists of perception, planning and control. As one of the key components of an autonomous driving system, the longitudinal planning module guides the vehicle to accelerate or decelerate automatically on the roads. A complete longitudinal planning module is supposed to consider the flexibility to various scenarios and multi-objective optimization including safety, comfort and efficiency. However, most of the current longitudinal planning methods can not meet all the requirements above. In order to satisfy the demands mentioned above, a new Potential Field (PF) based longitudinal planning method is presented in this paper. Firstly, a PF model is constructed to depict the potential risk of surrounding traffic entities, including obstacles and roads. The shape of each potential field is closely related to the property of the corresponding traffic entity.

The use of electric motors to independently control the torque of two or four wheels of a vehicle has the potential to significantly improve safety and handling. One virtue of electric motors is that their output torque can be accurately estimated. Using this known output torque, longitudinal tire force and coefficient of friction can be estimated via a controller output observer. This observer works by constructing a model of wheel dynamics, with longitudinal tire force as an unknown input quantity. A known wheel torque is input to the physical and modeled system and the resulting measured and predicted wheel speeds are compared. The error between the measured and predicted wheel speed is driven towards zero by a robust feedback controller. This controller modulates an estimate of longitudinal tire force used as an input by the wheel dynamics model. The resulting estimate of longitudinal tire force quickly converges towards the actual value with minimal computational expense.

Multi-body simulations are very powerful tools in the modeling of dynamic mechanical systems. This study uses the multi-body simulation program ADAMS to analyze a light vehicle suspension. The paper introduces ADAMS modeling concepts and then applies them in a case study examining the effects of additional longitudinal compliance on the ride and handling behavior of a 1/4 car suspension model. The results were a marginal increase in the lateral stiffness of the vehicle, approximately the same ride performance, and an increase in the compliance steering angle.

System identification is an important aspect in model-based control design which is proven to be a cost-effective and time saving approach to improve the performance of hybrid electric vehicles (HEVs). This study focuses on modeling and parameter estimation of the longitudinal vehicle dynamics for Toyota Prius Plug-in Hybrid (PHEV) with power-split architecture. This model is needed to develop and evaluate various controllers, such as energy management system, adaptive cruise control, traction and driveline oscillation control. Particular emphasis is given to the driveline oscillations caused due to low damping present in PHEVs by incorporating flexibility in the half shaft and time lag in the tire model.

All-wheel Drive (AWD) is a mature technology and most automobile manufacturers offer this feature on their vehicles. Improved traction, enhanced vehicle stability, and better handling are some of the key characteristics of AWD vehicles which are achieved by distributing the appropriate level of torque to the front and rear axles. Accurately capturing the torque split between the two axles is essential for sizing of driveline components like gears, bearings, and shafts. Traditionally, the torque split is considered to be either 50-50%, or solely proportional to the static weight distribution between the two axles. Design decisions are made based on historical test data. In this paper a longitudinal vehicle dynamics model for AWD systems is proposed to understand the influence of various key factors such as dynamic weight transfer, compliance of driveline components, and changing tire radius on the torque split.

Today, an increasing emphasis is being placed on vehicle transient operation improvement to accomplish better drivability and lower emission and fuel consumption. In this regard, dynamic simulatory model of powertrain-vehicle is a stepping-stone on the path to achieve this goal. In this study, a complete powertrain-vehicle model has been developed to predict vehicle performance and fuel consumption, with careful attention given to the engine dynamics (dynamic of air and fuel flows into the intake manifold, and crankshaft transient response). The model has been experimentally identified and validated for “Paykan 1600i”. Since there is a good agreement between vehicle test and simulation results, the model proposed in this study can be used in design and performance evaluation of vehicle powertrain system.

This paper describes a methodology to estimate longitudinal velocity of a 4-wheel-drive electric vehicle, in which wheel driven torque can be independently controlled by electric motor. Without non-driven wheels it would be difficult to estimate the vehicle longitudinal velocity precisely, especially when all of four wheels have large slip ratio. Therefore, an estimation methodology based on fuzzy logic is put forward, which uses four wheel speed and longitudinal acceleration as input signals. However, this method works not very well when two or more wheels have large slip ratio. In order to improve estimation effect, a state variable filter is designed to calculate wheel acceleration signals, which are used as additional signals to the fuzzy logic observer. Furthermore, the possibility of using four wheel driving torque signals to improve the estimation precision is also discussed.

Due to coupling of in-wheel motor and wheel/tire, the electric wheel system of in-wheel motor driven vehicle is different from tire suspension system of internal combustion engine vehicle both in the excitation source and structural dynamics. Therefore emerging dynamic issues of electric wheel arouse attention. Longitudinal vibration problem of electric wheel system in starting condition is studied in this paper. Vector control system of permanent magnet synchronous hub motor considering dead-time effect of the inverter is primarily built. Then coupled longitudinal-torsional vibration model of electric wheel system is established based on rigid ring model and dynamic tire/road interface. Inherent characteristics of this model are further analyzed. The vibration responses of electric wheel system are simulated by combining electromagnetic torque and the vibration model. The results indicate that abrupt changes of driving torque will cause transient vibration of electric wheel system.

Real-time simulation of tracked vehicle dynamics demands very efficient modeling of the vehicle track. Multi-body dynamics models which model the response of each track pitch are complete, but require on the order of 100 degrees of freedom to capture lateral track dynamics and an additional 200 degrees of freedom to capture longitudinal (stretching) track dynamics. The sheer size of such models renders them difficult to use for rapid estimates of track response. This paper summarizes an efficient alternative for modeling vehicle tracks, as illustrated herein by a model for longitudinal track dynamics. The present model is a hybrid discrete/continuous model in which the track is modeled as a continuous uniform elastic rod which is kinematically coupled to discrete models for the sprocket, wheels, and rollers. Solution efficiency derives from transforming the dynamic track model to one employing modal coordinates.

Anti-lock braking systems are one of the most important safety systems for wheeled vehicles. They reduce the braking distance and, most importantly, help the user maintain controllability and steerability of the vehicle. This paper extends and adapts the concept of Anti-lock braking systems to tracked vehicles, specifically to snowmobiles. Snowmobiles are an interesting development platform for two main reasons: 1) track dynamics, despite being analogous to tire dynamics, present important differences that help understanding the features of the control algorithm and 2) snowmobiles are simple and rugged vehicles with a limited set of sensors, making the design of an effective control system challenging. The paper designs a track-deceleration based ABS algorithm and tests it both in straight riding and cornering.

The sugarcane industry holds the second largest share of production value in the Brazilian agricultural sector, with Brazil responsible for more than 20% of the world’s production. Therefore, the increase of efficiency in the production process of sugarcane is an object of interest for producers, with transportation playing an important role in the process, both economically and environmentally. Intending to improve the efficiency in the transportation of sugarcane between cultivation and processing facilities, this work uses simulations to analyze safety aspects of a vehicle combination with 11 axles and 91ton capacity, new to the Brazilian transportation system. Several procedures were performed in a virtual environment to evaluate the vehicle longitudinal and lateral dynamics, including weight distribution, overtaking performance, rollover threshold, rearward amplification, braking and gradeability.

Advanced Driver Assistance Systems (ADAS) is an essential aspect of the automotive technology in this era of technological revolution, where the goal is to make vehicles more convenient, safe, and energy efficient. Taking advantage of more degrees of freedom available within vehicle “energy management” allows more margin to maximize efficiency in the propulsion systems. It is envisioned by this research that future fuel economy regulations will consider the potential benefits of emerging connectivity and automation technologies of vehicle’s fuel consumption. The application focuses on reducing the energy consumption in vehicles by acquiring information about the road grade. Road elevation are obtained by use of Geographic Information System (GIS) maps in order to optimize the controller. The optimization is then reflected on the powertrain of the vehicle. The approach uses a Model Predictive Control (MPC) algorithm that allows the energy management strategy to leverage road grade.

With the advent of autonomous vehicles, the human driver’s attention will slowly be relinquished from the driving task. It will allow drivers to participate in more non-driving related activities, such as engaging with information and entertainment systems. However, the automated driving system would need to notify the driver of upcoming points-of-interest on the road when the driver’s attention is focused on their screen rather than on the road or driving display. In this paper, we investigated whether providing directional alerts for an upcoming point-of-interest (POI) in or around the user’s active screen can augment their ability in relocating their visual attention to the POI on the road when traveling in a vehicle with Conditional Driving Automation. A user study (N = 15) was conducted to compare solutions for alerts that presented themselves in the participants’ central and peripheral field of view.

The commercialization of methanol fuel cell vehicles will offer practical, affordable, long-range electric vehicles while retaining the convenience of a liquid fuel. Given the automotive industry's strong commitment to develop methanol fuel cell vehicles, we must address the need for fueling infrastructure to serve these vehicles. From past experience in building methanol fueling stations, we estimate the cost to add methanol fueling capability to an existing gasoline station is $50,000. Assuming retail stations are required to cover North America, Europe and Japan, it would cost $1.9 billion for 10% of the existing stations and $4.7 billion for 25% of the stations.

High-speed cine photography has been used to study the combustion process in a variety of diesel chambers. These chambers, used in engines of 12–1200 cu in. swept volume per cylinder, differ considerably in the level of air utilization achieved within the cylinder at acceptable exhaust color or temperature. These differences are attributed to the method of fuel/air mixing employed and the influence of fuel injection, air motion, and fuel quality are discussed. It is concluded that while there is an obvious correlation between air utilization and the level of air swirl or turbulence employed, from other points of view high gas velocities are undesirable. Further development will therefore depend largely on the evolution of the fuel injection equipment toward the achievement of good mixing and combustion control with reduced gas velocities.

To secure the reliability of bolted joints, high clamping force (axial tension) is required to prevent fatigue breakage or loosening failure, and so on. In this paper, at first, we observe the behavior of the initial clamping force decrease tendency (loosening phenomenon) obtained by tightening the bolt used in the actual machine (large forklift) during operation. Based on our previous research, there is a strong linear relationship on log-log paper of loosening phenomenon between decrease tendency of clamping force and distance travelled (or passage of time). By utilizing its properties, we show estimation method of residual clamping force such as "How much the clamping force is remaining after the tens of thousands of hours (kilometers)?" Also, a method for estimating loosening lifetime with respect to residual clamping force level is shown. Finally, we examine evaluation criteria such as "Is the residual clamping force sufficient for prevention of loosening failure?"

This paper presents air monitoring data and references which show the following: Los Angeles photochemical and auto-caused air pollution is by far the worst in the U.S. Due to the control programs, Los Angeles air is much cleaner. The improvements are dramatic in the last few years. Downwind stations, such as Riverside, never had such high air pollution levels as Pasadena, and Riverside now is showing decreased levels. Sulfur dioxide and sulfate levels are not likely to reach as high levels in the early 1980's as were reached in the early 1950's before sulfur was limited in fuel oil.

In the discussion on the reduction or complete avoidance of CO2-emissions and other pollutants in the transport sector, hydrogen as a carbon-free fuel, is an alternative to conventional fuels. The use of hydrogen in modern internal combustion engines offers a fast and cost-effective opportunity of decarbonisation of the transport sector. The utilisation of hydrogen as fuel in internal combustion engine systems is more challenging than using conventional fuels. Hydrogen is highly flammable, which affects the requirements of the ignition system and the design of the combustion chamber. In addition, due to the gaseous state of H2 the question, how the fuel should be delivered to the combustion chamber is of high importance by means of engine performance. There are two fundamentally different concepts for hydrogen injection. Hydrogen can be injected by a multi-point injection into intake manifold by external mixture-formation (MPI) or directly into the combustion chamber (DI).

Partially Premixed Combustion (PPC) has demonstrated substantially higher efficiency compared to conventional diesel combustion (CDC) and gasoline engines (SI). By combining experiments and modeling the presented work investigates the underlying reasons for the improved efficiency, and quantifies the loss terms. The results indicate that it is possible to operate a HD-PPC engine with a production two-stage boost system over the European Stationary Cycle while likely meeting Euro VI and US10 emissions with a peak brake efficiency above 48%. A majority of the ESC can be operated with brake efficiency above 44%. The loss analysis reveals that low in-cylinder heat transfer losses are the most important reason for the high efficiencies of PPC. In-cylinder heat losses are basically halved in PPC compared to CDC, as a consequence of substantially reduced combustion temperature gradients, especially close to the combustion chamber walls.

The wireless charging system of electric vehicles will be of high power. Due to environmental problems and the heat emission design of the machines, it is not easy to improve the efficiency of the power transmitting system. While improving the efficiency of the overall system is important, it is especially significant to improve the efficiency of the transmitting and receiving antennas. Improving the antennas is necessary as it accounts for a large part of the overall efficiency and it has strong relation to the transfer characteristics. In this paper, the importance of reducing the antenna loss for high power implementation is discussed. We showed that the antenna losses not only affecting the transfer efficiency but also the maximum power consumed by the load (the available power) by deriving an equation.