325 research outputs found
Smart Procurement of Naturally Generated Energy (SPONGE) for Plug-in Hybrid Electric Buses
We discuss a recently introduced ECO-driving concept known as SPONGE in the
context of Plug-in Hybrid Electric Buses (PHEB)'s.Examples are given to
illustrate the benefits of this approach to ECO-driving. Finally, distributed
algorithms to realise SPONGE are discussed, paying attention to the privacy
implications of the underlying optimisation problems.Comment: This paper is recently submitted to the IEEE Transactions on
Automation Science and Engineerin
A New Terrain Classification Framework Using Proprioceptive Sensors for Mobile Robots
Mobile robots that operate in real-world environments interact with the surroundings to generate complex acoustics and vibration signals, which carry rich information about the terrain. This paper presents a new terrain classification framework that utilizes both acoustics and vibration signals resulting from the robot-terrain interaction. As an alternative to handcrafted domain-specific feature extraction, a two-stage feature selection method combining ReliefF and mRMR algorithms was developed to select optimal feature subsets that carry more discriminative information. As different data sources can provide complementary information, a multiclassifier combination method was proposed by considering a priori knowledge and fusing predictions from five data sources: one acoustic data source and four vibration data sources. In this study, four conceptually different classifiers were employed to perform the classification, each with a different number of optimal features. Signals were collected using a tracked robot moving at three different speeds on six different terrains. The new framework successfully improved classification performance of different classifiers using the newly developed optimal feature subsets. The greater improvement was observed for robot traversing at lower speeds
IMPLICATIONS OF SELF-PHASE MODULATION (SPM) FOR N2 FEMTOSECOND COHERENT ANTI-STOKES RAMAN SCATTERING (FS CARS) SPECTROSCOPY AT ELEVATED PRESSURE
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Femtosecond coherent anti-Stokes Raman scattering (fs-CARS) is a non-linear spectroscopic technique that has been widely used in various combustion related environments to measure the temperature and species concentration information. On the other hand, self-phase modulation (SPM) describes a Kerr-like effect in which an ultrashort pulse accumulates nonlinear phase as it propagates through the gas medium like N. As a result, the application of fs-CARS in the high pressure environment will inevitably need to deal with SPM influence especially when at high laser intensities. We evaluated the SPM effects by measuring the optical spectra of the ultrashort pulses as well as the fs-CARS spectrum transmitted through our custom-designed high-pressure vessel. Different SPM patterns and the extent of SPM were evaluated for gaseous species like N, CO and CH. With the suppression of SPM by reducing the laser intensity, fs-CARS spectrum in pure N was successfully fitted for pressure range from 1 to 10 bar. This study is meaningful not only for the study of fs-CARS measurement but also for all the other ultrafast spectroscopic studies at high pressure conditions, especially when the laser beams need to be focused or if the optical path inside the high pressure chamber is significant
A Distributed and Privacy-Aware Speed Advisory System for Optimising Conventional and Electric Vehicles Networks
One of the key ideas to make Intelligent Transportation Systems (ITS) work
effectively is to deploy advanced communication and cooperative control
technologies among the vehicles and road infrastructures. In this spirit, we
propose a consensus-based distributed speed advisory system that optimally
determines a recommended common speed for a given area in order that the group
emissions, or group battery consumptions, are minimised. Our algorithms achieve
this in a privacy-aware manner; namely, individual vehicles do not reveal
in-vehicle information to other vehicles or to infrastructure. A mobility
simulator is used to illustrate the efficacy of the algorithm, and
hardware-in-the-loop tests involving a real vehicle are given to illustrate
user acceptability and ease of the deployment.Comment: This is a journal paper based on the conference paper "Highway speed
limits, optimised consensus, and intelligent speed advisory systems"
presented at the 3rd International Conference on Connected Vehicles and Expo
(ICCVE 2014) in November 2014. This is the revised version of the paper
recently submitted to the IEEE Transactions on Intelligent Transportation
Systems for publicatio
Optimal Distributed Consensus Algorithm for Fair V2G Power Dispatch in a Microgrid
Among the many motivations to encourage the use of Electric Vehicles (EVs) there is the attractive possibility to implement Vehicle-to-Grid (V2G) functionalities. They are attractive both for EV owners, who can sell their own energy to the grid when they do not need to travel, and also for the power grid, as the stored energy can be used to back-up the fluctuating energy produced from renewable sources or to improve the grid stability at critical times. In this paper we illustrate a distributed algorithm that solves the V2G problem in a fair manner, trying to achieve an optimal trade-off between power generation costs and inconvenience to the vehicle owner. Results are shown and discussed for a case study simulated in the OpenDSS power system environmen
In-wheel motor vibration control for distributed-driven electric vehicles:A review
Efficient, safe, and comfortable electric vehicles (EVs) are essential for the creation of a sustainable transport system. Distributed-driven EVs, which often use in-wheel motors (IWMs), have many benefits with respect to size (compactness), controllability, and efficiency. However, the vibration of IWMs is a particularly important factor for both passengers and drivers, and it is therefore crucial for a successful commercialization of distributed-driven EVs. This paper provides a comprehensive literature review and state-of-the-art vibration-source-analysis and -mitigation methods in IWMs. First, selection criteria are given for IWMs, and a multidimensional comparison for several motor types is provided. The IWM vibration sources are then divided into internally-, and externally-induced vibration sources and discussed in detail. Next, vibration reduction methods, which include motor-structure optimization, motor controller, and additional control-components, are reviewed. Emerging research trends and an outlook for future improvement aims are summarized at the end of the paper. This paper can provide useful information for researchers, who are interested in the application and vibration mitigation of IWMs or similar topics
Emergence of central recirculation zone in a V-shaped premixed swirling flame
This paper presents an experimental study on the emergence of the central
recirculation zone (CRZ) in a V-shaped premixed swirling flame, using
simultaneous measurement of particle image velocimetry (PIV) and CH*
chemiluminescence. The results show that either increasing the Reynolds number
(Re) or decreasing the equivalence ratio ({\phi}) would facilitate the
emergence of CRZ, and the inner shear layer (ISL) plays an essential role in
governing the characteristics of CRZ. Further analysis demonstrates that the
CRZ emergence can be promoted by higher ISL intensity but suppressed by
enhanced viscous diffusion owing to higher flame temperature. As such, the CRZ
formation can be interpreted as the outcome of a competition between the ISL
intensity, i.e., circulation, and the vorticity consumption due to viscous
diffusion. This competition physically corresponds to a special Reynolds
number, Re_s, defined as the ratio between the ISL circulation ({\Gamma}) and
the ISL effective viscosity ({\nu}_s), with a simplified heat loss model
proposed for the temperature and viscosity estimations of the ISL. The
outputting {\Gamma}-{\nu}_s plot yields a single boundary line separating the
cases with and without CRZ, which points to a common critical Re_s of about
637, justifying the generality of the present criterion for lean-premixed
V-shaped swirling flames of various operating conditions. Unlike most previous
works which study the CRZ of a swirling flame from the point of vortex
breakdown, the present work reveals the importance of enhanced viscous
diffusion, caused by flame heating, in suppressing the CRZ emergence
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