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Heavy-duty Vehicles (heavy-duty + vehicle)

Distribution by Scientific Domains

Engineering	75%

Selected Abstracts

DYNAMIC ANALYSES AND ROBUST STEERING CONTROLLER DESIGN FOR AUTOMATED LANE GUIDANCE OF HEAVY-DUTY VEHICLES

ASIAN JOURNAL OF CONTROL, Issue 3 2000
Jeng-Yu Wang
ABSTRACT In this paper, we present various linear analyses of the linearized lateral dynamics of heavy-duty vehicles (HDVs) (tractor-semitrailer type), which include time domain, frequency domain and pole/zero analyses. These analyses are conducted to examine the vehicle response to the steering input subjected to variations of speed, road adhesion coefficient, cargo load in the trailer, and look-ahead distance for the lateral deviation sensor. These parameters (uncertainties) have significant influence on vehicle dynamics. It has been shown that redefining the look-ahead lateral error as the controlled output has a favorable impact on the lateral control problem. Based on these analyses, a robust steering controller using H, loop-shaping procedure is designed for a tractor semitrailer combination to follow the road center line on both curved and straight highway sections. The proposed controller ensures the robust performance under model uncertainties which include varying vehicle longitudinal speed, road adhesion coefficient, and cargo load in the trailer. The performance of the designed controller is evaluated by simulations and validated by experiments. [source]

Ecophysiological Response of Plants to Combined Pollution from Heavy-duty Vehicles and Industrial Emissions in Higher Humidity

JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 12 2006
Hong-Xia Cui
Abstract Pollution can be aggravated in industrial areas if traffic exhausts are mixed with industrial emissions under high humidity conditions. Plants growing in such environments may suffer from severe stress. The impact of vehicle emissions on urban vegetation in an industrial area in Qingdao, China, was investigated by studying seven plant species at visible, physiological and chemical levels. The traits of plant species in certain environmental conditions were compared between a clear area, Badaguan (BDG), and polluted area, Roadside (RS). We found that foliar sulfur uptake for all species was not significantly high at RS compared with BDG, although the sulfur content of atmosphere and surface soils at RS were much higher than those at BDG. For Ailanthus altissima Swingle, the content of foliar pigment and net photosynthesis rate (PN) decreased by 20%. Meanwhile, leaves became incrassate and no visible leaf damage was noted, suggesting this species could adapt well to pollution. A 50% decrease in PN occurred in Hibiscus syriacus L., but there was no statistical change in content of chlorophyll a and b and water uptake. Also, thickened leaves may prevent the pollutant from permeation. Foliar water content was still at a low level, although a water compensation mechanism was established for Fraxinus chinensis Rosb. reflected by low water potential and high water use efficiency. More adversely, a 65% decrease in PN happened inevitably with the significant decomposition of photosynthetic pigments, which exhibited visible damage. We also noted in one evergreen species (Magnolia grandiflora L.) that water absorption driven by low water potential should be helpful to supply water loss induced by strong stomatal transpiration and maintain normal growth. Furthermore, photosynthetic pigment content did not decline statistically, but supported a stable net assimilation. Two herbaceous species, Poa annua L. and Ophiopogon japonicus Ker-Gawl., were very tolerant to adverse stress compared to other woody species, especially in assimilation through a compensatory increase in leaf area. A more remarkable decline in PN (decrease 80%) was noted in the exotic but widespread species, Platanus orientalis L., with serious etiolation and withering being exhibited on the whole canopy. Our results suggested, special for woody species, that most native species are more tolerant to pollution and therefore should to be broadly used in a humid urban industrial environment with heavy-duty vehicle emissions. (Managing editor: Ya-Qin Han) [source]

On the attempts to optimize the performance and cost-effectiveness of TFPM drives: a crucial challenge for the automotive industry

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2005
Ahmed Masmoudi
Much attention is currently focused upon transverse flux permanent magnet machines (TFPMs), especially in automotive applications, in so far as, to date, they exhibit the highest power production capability. Different automotive manufacturers are currently involved in R&D programs dealing with TFPM concepts and the possibilities of their integration in electric and hybrid propulsion systems. This paper is devoted to the analysis of two R&D projects developed within the design of TFPMs intended for hybrid propulsion systems of heavy-duty vehicles. In spite of the increasing interest in TFPMs and the significant improvements brought to their earlier topologies, we can firmly state that further investigations remain to be carried out before the TFPM concepts could be regarded as a mature technology for the automotive industry. Copyright © 2005 John Wiley & Sons, Ltd. [source]