交通运输工程学报

Integrated optimal control model of freeway network based on particle swarm optimization

HAN Yin, GAN Hong-cheng, WU Jia-hao

Abstract: With nonlinear optimal control method, the integrated control problem of ramp and route guidance for freeway network was studied, and an integrated optimal control model was put forward. In the model, the control objective is to minimize the total time spent (TTS) of freeway network, METANET model was taken as the process model of traffic flow, the minimum updating cycles of control variables were considered, and the numerical solution of the model was achieved by using particle swarm optimization (PSO) method. Simulation result shows that TTS is 3 376 veh·h under uncontrol, TTS is 3 005 veh·h under only ramp control, TTS is 2 768 veh·h under only route guidance, and TTS is 2 464 veh·h under integrated control. Obviously, the control effect of integrated control is optimal. 3 figs, 14 refs.More>

2009, 9(1): 1-5. doi: 10.19818/j.cnki.1671-1637.2009.01.001

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Distribution properties of internal air voids in asphalt mixtures

WANG Hai-nian, HAO Pei-wen, LU: Guang-yin

Abstract: X-ray computed tomography(CT) technology was adopted to scan the internal structures of AC-16, SMA-16 and OGFC-16 mixture specimens compacted using Marshall and Superpave gyratory compactor(SGC) methods. Digital image processing technology was adopted to analyze the spatial distribution of their internal air voids. The result shows that the distributions of air voids are not uniform in mixture specimens, and they vary greatly with the compacting styles and gradations of asphalt mixtures. Throughout the specimen height, air void percents are bigger on the top and at the bottom, and are smaller in the middles of the specimens compacted by SGC method, whereas the distribution variances are not marked for the specimens compacted by Marshall method. Throughout the cross sections of the specimens, air voids distribute more in the outside parts than in the middle parts for AC-16 and SMA-16 mixtures. 3 tAbs, 11 figs, 10 refs.More>

2009, 9(1): 6-11. doi: 10.19818/j.cnki.1671-1637.2009.01.002

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Dynamic analysis of secondary suspension for low-speed maglev train

HE Zhuo-yu, LUO Shi-hui, LIANG Hai-qing

Abstract: Low-speed maglev train structures and kinematical relationships were analyzed, its dynamics model was developed by using multi-rigid-body dynamics modeling method, the movements of different components of secondary suspension in curve negotiation were analyzed, and the significance of parallelogram mechanism in curve negotiation was explained. Simulation result shows that parallelogram mechanism averagely distributes lateral forces among modules, so that modules are distributed reasonably along the curve. Parallelogram mechanism decreases the lateral and longitudinal forces of air spring, and the yawing angles of modules, which is helpful for curve negotiation and guidance. Speed influences lateral displacement to a certain extent, while the curve radius of the track is the major factor.More>

2009, 9(1): 12-16. doi: 10.19818/j.cnki.1671-1637.2009.01.003

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Torsional-longitudinal coupling vibration stability of drive system for locomotive

YAO Yuan, ZHANG Hong-jun, LUO Yun, JIN Ding-chang

Abstract: In order to investigate the stability of drive system under torsional-longitudinal coupling vibration for locomotive in slippage process, a dynamics model of drive system with single wheelset was set up, the torsional and longitudinal vibration freedoms of the wheelset were taken into account. The nonlinear differential equations of drive system vibration were linearized at the balance point, and its eigenvalues were calculated to judge the stability of the system, whose critical vibration curves were gained. Analysis result shows that the torsional vibration of drive system and the longitudinal vibration of wheelset are self-excited vibrations because of the negative slope of adhesion curve between wheel and rail, and their stabilities depend on wheelset's speed and axle load. The higher the velocity is and the lower the axle load is, the stabler the vibrations are. So the damps of torsional and longitudinal vibrations are able to suppress the unstable vibrations.More>

2009, 9(1): 17-20. doi: 10.19818/j.cnki.1671-1637.2009.01.004

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Effect of traction force on lateral stability of locomotive

SI Dao-lin, WANG Kai-yun, ZHAI Wan-ming, LIU Jian-xin

Abstract: In order to investigate the lateral stability of locomotive under traction condition, a dynamics model of a speed-raising locomotive was put forward by using MBS software SIMPACK. The nonlinear critical speed of locomotive was regarded as the judging index of the lateral stability. The numerical integration method was adopted to calculate the critical speed. The effect of the traction coefficient on the critical speeds was studied, including the speeds on tangent and curved tracks. The result indicates that the traction force influences the value and the direction of wheel/rail creep force greatly. The critical speed increases firstly with the increase of the traction coefficient, and then reduces. The critical speed on curved track is lower than that on tangent track under the same traction coefficient, and the smaller the curve radius is, the lower the critical speed is. It is pointed that the shift of wheelset should not be selected as the judging index of the lateral stability of locomotive, it is reasonable to judge the lateral stability using longitudinal creep force.More>

2009, 9(1): 21-24. doi: 10.19818/j.cnki.1671-1637.2009.01.005

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Finite element simulation on pantograph-catenary dynamic system for Beijing-Tianjin intercity high-speed railway

ZHOU Dong-peng, WU Jun-yong, WU Yan, ZHENG Ji-hao

Abstract: Based on the nonlinear finite element theory(FEM), a finite element model of the pantograph-catenary dynamic system of Beijing-Tianjin intercity high-speed railway was established, in which nonlinear flexible catenary was modelled by using Euler-Bernoulli flexible beam and the pantograph was modelled by using hinge and nonlinear springs. The dynamic current-collecting performance of the system was simulated by using MARC software, and using whose post-processing function, the three dimensional dynamic performance of pantograph-catenary was shown. Computation result shows that the average pantograph-catenary contact pressure is 160.68 N and the dynamic uplift of contact position is between 28.5 mm and 87.0 mm. Compared with the simulation result provided by Siemens and the measure result, the model is correct and credible, the dynamic current-collecting performance is perfect.More>

2009, 9(1): 25-28. doi: 10.19818/j.cnki.1671-1637.2009.01.006

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3-DOF vehicle steering model and state equations based on considering air forces

ZHOU Yu-cai, HE Ren, CHEN Shi-an, GU Bin-bin

Abstract: In oder to decrease the influence of air forces, predigest the multiple-DOF steering dynamics equations of vehicle, air forces were considered, a 3-DOF steering dynamics model was proposed. The state equations of the model was induced, sideslip angle in mass vehicle center, yaw angle, yaw velocity, roll angle and roll velocity were state variables, steering angle in front axle and crosswind force were input variables, sideslip angle in vehicle mass center, yaw angle, yaw velocity, roll angle were output variables. The simulation credibility of the equations was validated by using a test vehicle with an active steering angle pulse. The simulation result with the 3-DOF model and equations was compared with that from 2-DOF steering dynamics model. Comparison result shows that the Absolute values of sideslip angle and yaw velocity from the 3-DOF model and equations are less, which indicates that air forces strengthen the lacking steering property of vehicle. The sideslip values gained by the tow models are larger than the test value, but the value gained by the 3-DOF model is closer to the test value. Obviously, the credibility of the 3-DOF equations is higher.More>

2009, 9(1): 29-34. doi: 10.19818/j.cnki.1671-1637.2009.01.007

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Design of variable structure controller for active steering vehicle

DU Feng, WEI Lang, ZHAO Jian-you

Abstract: In order to improve the safety of vehicle during emergency obstacle avoidance and critical state, sliding mode variable structure control strategy was studied for active four-wheel steering vehicle based on steer-by-wire technology. A variable structure controller was designed for active steering vehicle, the cornering stiffnesses of the front and rear tires and the outer disturbance of an actual vehicle were treated as uncertain parameters, but their variances were in limited ranges, and a certain linearity vehicle model with certain parameters was taken as an ideal following goal. Based on driver-vehicle-road closed loop system, simulation result indicates that four-wheel steering vehicle with variable structure controller can maintain near zero sideslip angle and desired yaw rate, and its path errors are only 0 m and 0.05 m after changing line. Obviously, the controlled vehicle system behaves favorable performance for following path and robustness for uncertainty, its handleability and active safety are improved.More>

2009, 9(1): 35-39. doi: 10.19818/j.cnki.1671-1637.2009.01.008

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Influence of spray performance on combustion and emission characteristics of biodiesel

CHEN Hao, QI Dong-hui, BIAN Yao-zhang

Abstract: Spraying comparison experiments were conducted on a press pump test-bed, and combustion and emission performance comparison experiments between biodiesel and diesel were done on a single cylinder direct-injected diesel engine. The diameter size distribution of liquid drop and the characteristic parameters of fuels were analyzed, the combustion and emission difference between diesel and biodiesel and the reasons were studied. Study result indicates that, compared with diesel, the spray angle of biodiesel is smaller, the total amount of drop is less, the proportion of small diameter drop is lower, and the maximal diameter is larger. When rotation speed is 1 500 r·min-1 and average effective pressure is 0.531 MPa, the maximal combustion pressure, and the pressure increase ratio and heat release ratio of biodiesel decrease by 1.91%, 30.10% and 29.32% respectively, continual combustion period of biodiesel is longer. When rotation speed is 1 500 r·min-1, the emissions of HC, CO and smoke for burning biodiesel decease by 17.17%, 26.73% and 37.85% respectively, and the emission of NO_X increases by 21.93%.More>

2009, 9(1): 40-43. doi: 10.19818/j.cnki.1671-1637.2009.01.009

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Mix design method of porous concrete with non-vibration molding

SHENG Yan-ping, CHEN Shuan-fa, ZHENG Mu-lian, ZHANG Deng-liang

Abstract: In order to ensure the smoothness of porous permeable concrete base, volume method was used for the mix design of non-vibration porous permeable concrete base, mix proportion parameters, dilution coefficience, reasonable water cement ratio and water consumption were calculated, the evaluating method and index for the workability of non-vibration porous permeable concrete base were given, such as margin cement mortars method and margin cement mortars ratio. Through orthogonality design, the regression equation of margin cement mortars ratio and the relationship between 7 d compression strength and effective porosity were obtained, and the mix design method of porous concrete with non-vibration molding was indicated on the basis of empirical formulas. Analysis result shows that the mixture designed by the method can satisfy the design standard that 7 d compression strength is 3~5 MPa for heavy traffic and 5~8 MPa for special heavy traffic, effective porosity is 20%³0%, so the design method is feasible. 10 tAbs, 13 refs.More>

2009, 9(1): 44-49. doi: 10.19818/j.cnki.1671-1637.2009.01.010

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Roughness measurement of aggregate surface texture

ZHOU Chun-xiu, CHEN Guo-ming, TAN Yi-qiu

Abstract: In order to effectively evaluate the remarkably influence of the roughness of aggregate surface texture on the pavement performance of asphalt mixture, nine different aggregate surface textures were measured directly by using laser profilometer, then the textures were divided into micro-textures and macro-textures by using profile filter method. Geometry statistical method was adopted to evaluate the roughnesses of the textures quantitatively. The evaluation indexes were arithmetic mean deviation, arithmetic mean wavelength and outline skewness. Evaluation result indicates that arithmetic mean deviation is the most conformable index to describe the roughness of aggregate surface texture. Moreover, with the increase of arithmetic mean deviation, the roughness of aggregate surface texture change larger. Aggregate surface textures are divided into macro-textures and micro-textures according to 2 mm wavelength limit. The roughnesses of aggregate surface textures can be classified into four different grades according to arithmetic mean deviation.More>

2009, 9(1): 50-55. doi: 10.19818/j.cnki.1671-1637.2009.01.011

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Effects of gyration compaction number on design and performance of Superpave mixture

ZHAO Yan-qing, PAN You-qiang, TAN Yi-qiu

Abstract: In order to study the effects of gyration compaction number on the design and performance of Superpave mixture, Superpave 20 and Superpave 25 asphalt mixtures were designed by using different gyration compaction numbers (75, 100 and 125), and the various mixtures were evaluated by conducting wheel rutting, low-temperature bending beam, immersion Marshall stability and freeze-thaw split tests, asphalt film thicknesses were calculated, and corresponding field test sections were constructed. Test result shows that the increase of gyration compaction number for Superpave mixture does not necessarily decrease asphalt design content; the increase of gyration number by 25 can improve the dynamic stability of asphalt mixture by approximately 15%~30%. Gyration compaction number has negligible influences on the low-temperature performance and moisture damage susceptibility of asphalt mixtures, and asphalt film thickness increases with the increase of gyration compaction number. When aggregate properties and construction technologies meet the requirements, the field performance of asphalt mixture can be improved by increasing the design gyration compaction numbers.More>

2009, 9(1): 56-61. doi: 10.19818/j.cnki.1671-1637.2009.01.012

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Calculation method of transversal distribution factor for bridge load

LIU Hua, YE Jian-shu, YU Bo, LI Hai-sheng

Abstract: The load transversal distribution of bridge was confirmed according to the transversal distribution rule of main girder's vertical displacement. The modal parameters of bridge structure, such as natural frequency, modal shape and modal mass, were considered. A modal parameter method of calculating load transversal distribution factor was advanced for all kinds of bridge structure types. A test bridge model made of organic glass and a highway skew T bridge were selected to discuss the applying steps of the method. Computation result shows that the maximal difference between the computation value and the test value is only 2.6%, so the method for calculating the factor is more universal and exact than other traditional methods, and reduces the error resulted from the classification and assumption of bridge structures.More>

2009, 9(1): 62-66. doi: 10.19818/j.cnki.1671-1637.2009.01.013

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Numerical analysis of moisture, thermal and mechanical states for subway double-line tunnel constructed by artificial freezing method

LI Shuang-yang, ZHANG Ming-yi, HUANG Zhi-jun, DONG Yuan-hong

Abstract: In order to accurately analyze the thermal and mechanical states of subway tunnel constructed by artificial freezing method, the coupled effects of moisture transfer and phase change of ice and water, the generation of cement hydration heat and thermal creep constitutive relationship were taken into account, and a moisture, thermal and mechanical coupled model was established. The thermal and mechanical states of Guangzhou subway double-line tunnel constructed by artificial freezing method were simulated, and the safety of frozen wall was evaluated by using the long-term strength of frozen soil. Analysis result shows that the maximum principal stress distributes circularly along freezing pipes when the subway tunnel is constructed by artificial freezing method, and the stress around freezing pipes is obviously high. Excavation has little influence on circular stress field, the surface settlement caused by artificial freezing construction doesn't increase with excavation expansion, which is different from other construction methods. The maximum settlement is only 9.1 mm during the whole construction, so the surface settlement can be effectively controlled by artificial freezing method.More>

2009, 9(1): 67-72. doi: 10.19818/j.cnki.1671-1637.2009.01.014

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Ship target detection algorithm on sea surface based on block chaos feature of image sequence

HE Si-hua, YANG Shao-qing, SHI Ai-guo, LI Tian-wei

Abstract: In order to detect ship target on complex sea surface background, a new algorithm based on the block chaos feature of image sequence was proposed, the block largest Lyapunov exponent of image sequence was calculated by using small data sets, the change of background chaos feature was analyzed when moving target existed, ship target signal submerged by background signal was detected based on the change difference of chaos feature, and 100 frame images were used to detect ship target. Experiment result shows that the detection rate of the proposed algorithm is 100%, its false alarm rate is 5%, so the algorithm is superior to statistical analysis method.More>

2009, 9(1): 73-76. doi: 10.19818/j.cnki.1671-1637.2009.01.015

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Improved algorithm for inverse solution of Bessel's geodetic problem

SHI Guo-you, ZHAO Qing-tao, WANG Yu-mei, JIA Chuan-ying

Abstract: In order solve the nonuniform algorithms of Bessel's inverse problem and the application restrictions of the algorithms, sine and cosine theories based on sphere triangle and Lagrange series theory were analyzed, and an improved arithmetic of differential correction for the direct inverse solution of geodetic problem was put forward by using computer algebra system. Simulation result shows that the improved algorithm is suitable for the arbitrarily special situations without iterative calculations, and has high accuracy of 0.000 1 s when geodetic length is less than 20 000 km. The azimuth multiple-valued corresponding problem in the solution of trigonometric equation is solved. The improved algorithm is also suitable for the program implementation without generality loss, and can be applied in the area of ocean geodetic line sailing computation.More>

2009, 9(1): 77-82. doi: 10.19818/j.cnki.1671-1637.2009.01.016

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Microscopic simulation model of passenger mustering and evacuation in passenger dedicated railway station

LI De-wei, HAN Bao-ming

Abstract: In order to optimize the design of passenger dedicated railway station, the mechanism of passenger flow generation was studied, passenger mustering and evacuation process was described by using a standard Markov decision process, a method of facility control based on logical network and point matrix was presented, and a microscopic simulation model of passenger mustering and evacuation was proposed for passenger dedicated railway station. Simulation result shows that the maximum flow appears when passenger space is about 0.5 m², the speed distributes between 20 m·min^-1 and 80 m·min^-1 and increases exponentially with density. Passenger patterns are different according to facility types despite of the same passenger flow input. The simulation of passenger behavior reproduces the self-organization phenomenon successfully, and avoids the inapplicable data sample range of traffic flow fundamental diagram. So the model is reliable and practical.More>

2009, 9(1): 83-86. doi: 10.19818/j.cnki.1671-1637.2009.01.017

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Estimation model and algorithm of multi-mode path flow

LI Shu-guang, JU Yong-feng, JI Jian-gang

Abstract: In order to calculate multi-mode traffic demand from traffic counts under congested conditions, a multi-mode path flow estimation model with stochastic user equilibrium was presented, and an augmented Lagrange dual algorithm was given. Link capacity, flow equilibrium and priori demand constraints were transformed into penalty functions. The original constraint optimal flow estimation model was transformed into non-constraint optimal model, and a simple projection algorithm was adopted for non-constraint optimal model. Simulation result shows that the smaller the priori demand error is, the better OD estimation results are; the priori demand error has little influence on link flow estimation result, therefore, the estination model and algorithm are simple and applicable.More>

2009, 9(1): 87-91. doi: 10.19818/j.cnki.1671-1637.2009.01.018

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Scale parameter of discrete choice model based on extreme value distribution

ZHENG Ke, ZHENG Yong

Abstract: In order to understand the role of scale parameter in the process of modeling, analysis and application, multinomial logit model and nested logit model were discussed based on extreme value distribution. Starting with the distribution of error terms, the properties of scale parameter in two models were studied in aspects of model expressions and error term properties, and a comparison analysis was made. Analysis result shows that scale parameter not only restricts the scale of utility function, but also reflects the variance of error terms. However, it reveals different properties at two different models in terms of scale restriction, variance and independence degree of error terms, and numerical areas. For multinomial logit model, the scale parameter reflects the variance of entire error terms, while for nested logit model, it only reflects the variance of a part concerning the observed term for a specific alternative.More>

2009, 9(1): 92-95. doi: 10.19818/j.cnki.1671-1637.2009.01.019

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Modeling of commuters' day-to-day route choice behaviors based on reference-dependent approach

FAN Wen-bo, LI Zhi-chun, JIANG Ge-fu

Abstract: In order to investigate commuters' day-to-day route choice behaviors under travel time uncertainty, a novel model was presented based on reference-dependent approach, a reference-dependent route disutility function was introduced, and commuters' day-to-day route choice behaviors obeyed the decision process based on logit model, a day-to-day evolution model of route choice was proposed, in which the equilibrium for every day's route choice was kept. The stability of evolution model was analyzed and solved by a heuristic solution algorithm combining the method of successive averages with logit assignment technique. Analysis result shows that network flows and reference point come into steady state after several days' evolution, and traditional expected utility models underestimate total network user cost and overestimate the benefits from road capacity expansion or road pricing policies in amount of 1%.More>

2009, 9(1): 96-99. doi: 10.19818/j.cnki.1671-1637.2009.01.020

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Capacity control models and approaches in airline network

LI Jin-lin, XU Li-ping

Abstract: In order to improve the revenue management capability of transport network system, the problem of network capacity control in strategies, models and methods was studied systematically under the background of airline network, three kinds of network control strategies were discussed such as partition booking limits, virtual nesting control and bid price control. Traditional network models and new sophisticated models were analyzed, and the new models were classified as stochastic dynamic program model, hybrid model, stochastic dynamic program model with multiple stages, and Scenario tree model. The approaches based on resources decomposition were studied. It was pointed that for constructing the network strategy, both the principle of decomposition and the single-leg capacity control model should be jointly considered. Analysis result indicates that the models and approaches of network capacity control must be efficiently combined with correct control strategies to achieve the maximum expected total revenue. 31 refs.More>

2009, 9(1): 100-108. doi: 10.19818/j.cnki.1671-1637.2009.01.021

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Taxi route optimization algorithm of airport surface based on multi-agent

YOU Jie, HAN Song-chen

Abstract: In order to protect airport security and improve operational efficiency, a multi-agent model was developed based on the decision of the shortest taxi time for arrival and departure flights and multi-agent technology, the ideas of selection optimal route in Dijkstra algorithm and contract net protocol were considered, a route optimization algorithm was founded, and simulation analysis was made. Analysis result shows that the total running time can reduce by 15 s compared with the designated priority flights when mult-agent algorithm is used to deal with same prionity flights, and the algorithm can effectively adjust aircrafts and sources at airport, such as taxiways, runways and gate positions, discover and avoid the conflict intelligently, and achieve the shortest time of overall taxiway, so the algorithm is feasible.More>

2009, 9(1): 109-112. doi: 10.19818/j.cnki.1671-1637.2009.01.022

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Revenue allocation model for port cooperation with considering of risk and contribution

WANG Chuan-xu, ZHANG Su

Abstract: In order to effectively stimulate the port cooperation and achieve the improvement of all individual ports' benefit, the contribution to cooperation and the risk in cooperation were considered, a nonlinear programming model was developed to design revenue allocation scheme in port cooperation according to the principles of mutual benefits, contribution-income matching, risk-income matching, a numerical example was given to demonstrate the effectiveness of the model. Analysis result shows that the individual port revenue obtained by the proposed model is greater than that when individual port operates separately, and the sum of individual port revenue is equal to the total revenue of three port cooperations, so the model can bring high economic benefit and realize the reasonable distribution of economic benefit.More>

2009, 9(1): 113-119. doi: 10.19818/j.cnki.1671-1637.2009.01.023

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Evaluation of driver safety characteristic in desert environment based on fuzzy comprehensive evaluation model

SIMUTULA Ai-li, LI Xin

Abstract: In order to reveal the relationship between driving characteristics and traffic accidents on desert highway, the key factors of influencing driver safety characteristics were selected, the correlation analysis was made based on driver aptitude test data on desert highway, a fuzzy comprehensive evaluation model of driving behavior was set up, and the dynamic analysis of driving safety characteristics was made. Study result shows that, due to the influences of unique traffic conditions, nature environmental factors, physical and psychological characteristics, drivers have strong orientation of accident on desert highway; among the factors of influencing driving safety, the main factor is air temperature, while others are continuous driving time, driving experience and driver's age in sequence.More>

2009, 9(1): 120-126. doi: 10.19818/j.cnki.1671-1637.2009.01.024

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