AUTOMOBILE engines, VIRTUAL reality, COMPUTER simulation, EQUATIONS, MECHANICS (Physics), and STATICS

The virtual test track (VTT) is a real-time vehicle simulator used for powertrain and chassis system development in a virtual environment, The VTT is designed and built based on the rapid control prototyping (RCP) concept Therefore, different from the conventional vehicle simulator, the VTT can provide many additional benefits, such as ease of use, flexibility of interface with other devices, and ability to easily implement any hardware-in the-loop system. The VTT consists of a powerful simulation engine to solve the equations of a complicated vehicle dynamics model in real-time and a sophisticated animation engine to provide real-time visual representation of vehicle behavior. It also contains multiple virtual test environments with variable surfaces and weather conditions to provide different types of driving conditions. [ABSTRACT FROM AUTHOR]

COLLISION avoidance systems in automobiles, ELECTRIC vehicles, AUTOMOBILE brakes, AUTOMOBILE drivers, RAPID control prototyping, SAFETY, and ATTITUDE (Psychology)

This paper presents a new control scheme for longitudinal collision avoidance (CA) systems to improve the safety of four-in-wheel-motor-driven electric vehicles (FIWMD-EVs). There are two major contributions in the design of longitudinal CA systems. The first contribution is a new safety distance model to make vehicle adapt to different driving roads with an adhesive coefficient between tire and road and to conform to drivers' characteristics with a driving intention parameter. The second contribution is a new braking force distribution strategy based on constrained regenerative braking strength continuity (CRBSC). By optimizing the braking force distribution curve of hydraulic proportional-adjustable valve, the safety-brake range could be linearized to simplify the calculation of braking force distribution on the premise of ensuring braking safety. Furthermore, it is the constraint conditions that could solve the coexistence problem of positive and negative braking forces based on regenerative braking strength continuity (RBSC) to conform to actual requirements. The feasibility, effectiveness, and practicality of the proposed safety distance model and braking force distribution strategy are, respectively, verified by computer simulation experiments. Rapid control prototyping (RCP) and hardware-in-the-loop (HIL) simulation experiments using dSPACE are carried out to demonstrate the effectiveness in the control scheme, simplicity in structure, and flexibility in implementation for the proposed longitudinal CA system. [ABSTRACT FROM AUTHOR]

MARKOV processes, HYBRID electric vehicles, MOTOR vehicle driving, VELOCITY, and MOTOR vehicle design & construction

This paper describes a new method to synthesize driving cycles, where not only the velocity is considered but the road slope information of the real-world measured driving cycle as well. Driven by strict emission regulations and tight fuel targets, hybrid or electric vehicle manufacturers aim to develop new and more energy- and cost-efficient powertrains. To enable and facilitate this development, short, yet realistic, driving cycles need to be synthesized. The developed driving cycle should give a good representation of measured driving cycles in terms of velocity, slope, acceleration, and so on. Current methods use only velocity and acceleration and assume a zero road slope. The heavier the vehicle is, the more important the road slope becomes in powertrain prototyping (as with component sizing or control design); hence, neglecting it leads to unrealistic or limited designs. To include the slope, we extend existing methods and propose an approach based on multidimensional Markov chains. The validation of the synthesized driving cycle is based on a statistical analysis (as the average acceleration or maximum velocity) and a frequency analysis. This new method demonstrates the ability of capturing the measured road slope information in the synthesized driving cycle. Furthermore, results show that the proposed method outperforms current methods in terms of accuracy and speed. [ABSTRACT FROM AUTHOR]

ESTIMATION theory, CONTROL theory (Mathematics), FAULT-tolerant control systems, FLOW sensors, FLOW (Fluid dynamics), and KALMAN filtering

This paper aims at developing integrated onboard diagnosis and fault-tolerant control methods with experimental validation for a urea selective catalyst reduction (SCR) aftertreatment system to reduce vehicle tailpipe emissions. Diagnostics are performed for an SCR urea injection system by estimating and monitoring the injected urea mass flow with no need for a costly physical flow sensor. The estimation is derived from a first-principle-based urea injection system model, and the model parameters are identified by using system identification. During vehicle transient maneuvers, a Kalman filter (KF) is formulated to further reduce the estimation noise and improve diagnostic robustness. Once an injection fault is detected, an adaptation control algorithm is applied to compensate the urea injection command, thus correcting certain types of urea under/overdosing faults and maintaining the SCR \mboxNOx conversion performance. These methods have been validated through vehicle tests by utilizing an onboard rapid prototyping control system. [ABSTRACT FROM AUTHOR]

MOBILE communication systems, WIRELESS communications, INTERNET, COMPUTER network protocols, INFORMATION networks, INFORMATION resources, TELEPHONE answering services, RAPID prototyping, and VEHICLES

As portable devices are gaining more popularity, maintaining Internet connectivity anytime and anywhere becomes critical, particularly for mobile and vehicular networks. Network mobility (NEMO) and Internet Protocol mobility are gaining more and more importance. In this paper, we develop a Session Initiation Protocol (SIP)-based mobile network architecture to support NEMO for vehicular applications. We propose to form a mobile ad hoc network (MANET) by the mobile hosts (MHs) inside a vehicle or a cluster of vehicles. The MANET is connected to the outside world via a SIP-based Mobile Network Gateway (SIP-MNG), which is equipped with one or multiple external wireless interfaces and some internal IEEE 802.11 interfaces. The external interfaces of the SIP-MNG support Internet connectivity by aggregating user traffic to and from the Internet. In addition, exploiting the session information carried by SIP signaling, the SIP-MNG supports resource management and call admission control for the MHs. However, wireless access incurs charges, power consumption, and overhead of mobility management. So, it is desirable to allow the SIP-MNG to disconnect its external interfaces when necessary. To guarantee that users inside the mobile network will not lose any incoming request, we propose a push mechanism through short message service to wake up these wireless interfaces in an on-demand manner. We show the detailed signaling to support such a mechanism. The proposed system is fully compatible with existing SIP standards. Our real prototyping experience and some experimental results are also reported. [ABSTRACT FROM AUTHOR]

PROTOTYPES, TRANSPORTATION, LABORATORIES, COMPUTER software, VEHICLES, and INTERFACES (Physical sciences)

Complex vehicle systems (CVSs) are prototyping systems that are used to demonstrate a new functionality Inside a prototype vehicle. This study focuses on an evolutionary validation process for CVSS based on a VMEbus architecture. Due to the prototype character of the system, its properties are subject to change throughout the development process. Therefore, a validation system that can be easily adapted to these changes is needed. The architecture of a feasible validation system will be described. For an exact validation of any kind of unit under test (UUT), the black-box principle should be used. To realize this kind of validation, the CVS has to be connected via its hardware interfaces to the mentioned validation system. Al alternative methodology, which looks directly inside the software of the CVS, will be presented. In this case, the connection of the UUT via Its hardware interfaces is avoidable. The mentioned methodology slightly affects the discovery of failures, but there is a large benefit in development time. This kind of validation Shifts the test process from the road to the laboratory. The operation of such a validation system will be shown by an example. [ABSTRACT FROM AUTHOR]

BROADBAND communication systems, MEAN square algorithms, ANTENNAS (Electronics), RADIO-on-fiber systems, and ORTHOGONAL frequency division multiplexing

We have been developing a minimum-mean-square-error macrodiversity (MMSE-MD) reception system using distributed remote antennas and radio-on-fiber (RoF) links for use in live broadcasts of road races. The system selects remote antennas with good signal quality and combines their signals based on the MMSE algorithm to combat both small-scale and large-scale fading. For the system to be feasible, we have to consider propagation delay differences among diversity branches due to the RoF links and radio propagation. This paper describes a practical delay difference correction (DDC) technique that can keep signal continuity in any situation, the hardware implementation of an MMSE-MD receiver embodying the technique, and indoor and outdoor performance evaluations. Our prototype receiver perfectly corrected the propagation delay differences among diversity branches without losing signal continuity and maintained MD reception without signal outage across a wide area on an actual road-race course. [ABSTRACT FROM PUBLISHER]