Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Yu. Kluchka
Аvtomob?lnyi Transport , 2011,
Abstract: The analytical dependence of density, volume andenthalpy of gaseous and liquid hydrogen in the tank on tank volume, mass and temperature of stored hydrogen (in the range 20–32 K).
Autonomous Cargo Transport System for an Unmanned Aerial Vehicle, using Visual Servoing
Noah Kuntz,Paul Oh
Journal of Systemics, Cybernetics and Informatics , 2009,
Abstract: This paper presents the design and testing of a system for autonomous tracking, pickup, and delivery of cargo via an unmanned helicopter. The tracking system uses a visual servoing algorithm and is tested using open loop velocity control of a six degree of freedom gantry system with a camera mounted via a pan-tilt unit on the end effecter. The pickup system uses vision to direct the camera pan tilt unit to track the target, and uses a hook attached to a second pan tilt unit to pick up the cargo. The ability of the pickup system to hook a target is tested by mounting it on the Systems Integrated Sensor Test Rig gantry system while recorded helicopter velocities are played back by the test rig.
The Vibration of Partially Filled Cylindrical Tank Subjected to Variable Acceleration  [PDF]
Omar Badran, Mohamed S. Gaith, Ali Al-Solihat
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.49069
Abstract: In this study, the vibration of a cylindrical tank partially filled with liquid under motion modeled as mass lumped is investigated. A three-dimensional quasi-static model of a partially-filled tank of circular cross-section is developed and integrated into a comprehensive three-dimensional vehicle model to study its dynamic performance as a function of acceleration, and the fill volume. The liquid load movement occurring in the roll and pitch planes of the tank is derived as a function of the longitudinal acceleration, and then the corresponding shifted load is expressed in terms of center of mass coordinates and mass moments of inertia of the liquid bulk, assuming negligible influence of fundamental slosh frequency and viscous effects. The vibration characteristics of the partially filled tank vehicle are evaluated in terms of load shift, forces and moments induced by the cargo movement, and dynamic load transfer in the longitudinal direction. The semi analytical response is obtained by means of SimuLink? Matlab Software. The effects of longitudinal acceleration of the tank system on the liquid surface inclination and consequently shifting of centroids and moment of inertia are illustrated.
Simulation Based Design of Retention Tank of Modular Controller Discharge System (MCDS) for Train Coaches  [PDF]
Rajesh Kumar Garg,Vikram Singh
International Journal on Computer Science and Engineering , 2010,
Abstract: As increasingly more complex embedded systems are being considered for design, their design and validation is proving a Herculean task. Innovative applications demand stringent requirements, necessitating improvements in technologies and system design methodologies. It is where simulation and modeling come in to picture. Modern embeddedsystem design philosophy is heavily dependent on simulation. Simulation provides a means to model an embedded system, perform experiments with the model, test, and evaluate the designs prior to committing to implementation, thus allowing design flaws to be detected and corrected early in the design process. In this paper, the design for retention tank of Modular Controller Discharge System (MCDS) is proposed which is a modernized toilet system for trains to avoid the spillage at undesired places or at railway platforms. Speed sensors help to dump the waste at a suitable distance from the railway station. Intermediate tank is used under the toilet seat and it is designed using simulation. A Programmable Logic Controller is used to control the action of storage tank.
Design of mountain orchard detachable unidirectional traction double track cargo vehicle

- , 2015,
Abstract: 为克服现有山地果园轨道运输机无法搬移、户外施工难度大、批量生产困难和设备利用率低等问题,设计了一种山地果园拆装单向牵引式双轨运输机,分析该机的总体结构及绳径选择、轨道最小倾角、轨道最长长度、轨道最小转弯半径和断绳制动装置的工作原理,并进行样机运载试验。计算与分析结果显示: 运输机钢丝绳直径为7.7 mm, 轨道最小倾角为5.7°, 轨道最长长度为170 m, 轨道最小水平转弯半径为7 m, 最小垂直转弯半径为2 m。运载试验结果显示:运输机上行平均速度为0.51 m/s,下行平均速度为0.54 m/s,平均能耗为1.235 kW·h,使用有效度为100%。这表明该运输机可适用于山地果园运送肥料和果品等,亦可搭载喷雾机或果枝修剪机械等进行作业。
In order to overcome the transition,field operation, and standardized batch production difficulties of the existing track cargo vehicle in mountainous orchard, as well as to raise the utilization rate, the mountain orchard detachable unidirectional traction double track cargo vehicle was developed. This paper introduced the whole machine structure, the wire rope diameter selection,the minimum track inclination,the maximum track distance,the minimum track turning radius and the working principle of the rope brake device. Load experiments were carried out to test the cargo′s synthetic track function. It is indicated by calculation that the wire rope diameter should be 7.7 mm,the minimum track inclination was 5.7°, the maximum track distance was 170 m, the minimum track horizontal turning radius was 7 m, and the minimum track vertical turning radius was 2 m. Load experiment results indicated that the cargo vehicle′s uplink average speed was 0.51 m/s, the downlink average speed was 0.54 m/s, the average energy consumption was 1.235 kW·h and the effective use degree was 100%. This cargo vehicle was suitable for fruit, pesticide, chemical fertilizer and other cargo transportation in the mountain orchard. Meanwhile, it can be applied to carry the spraying machine, the shave machine and other agricultural machines.
Effects of openings and nozzles on the load-carrying capability of a horizontal tank

- , 2016, DOI: 10.16511/j.cnki.qhdxxb.2016.23.015
Abstract: 压力容器上都不可避免地有开孔接管, 从而可能影响容器的承载能力。该文采用有限元方法分析了一个带有接管卧式容器的外压临界载荷和内压极限载荷, 并通过改变接管大小和接管壁厚来考察开孔接管的影响。研究发现: 开孔接管并没有降低卧式容器的外压承载能力, 但会降低设备的内压极限承载能力; 壁厚相同时开孔接管的直径增大, 对外压失稳临界压力几乎没有影响, 但塑性极限载荷值会明显降低; 开孔接管直径相同, 壁厚增大, 设备的外压临界载荷稍有增加, 而塑性极限载荷明显提高。
Abstract:Openings and nozzles in a pressure vessel may affect the load-carrying capability of the vessel. Finite element method was used to analyze the critical load of a horizontal vessel with a nozzle under external pressure loading and the limit load under internal pressure loading, with the effects of openings and nozzles with different sizes and thicknesses on the load-carrying capability of the horizontal tank being specially investigated. The results show that the critical load showing the vessel instability almost keeps constant when a nozzle is present at an opening, but that the limit load reflecting the vessel strength obviously decreases. For the same nozzle thickness, with increasing nozzle diameter, the limit load of the vessel remarkably decreases, with the critical load under the external pressure keeping constant. For the same nozzle diameter, the limit load of the vessel significantly increases with increasing nozzle thickness, with the external pressure increase being very limited.
Vehicle loading spectrum and fatigue truck models of heavy cargo highway

- , 2017,
Abstract: 为研究货运繁重公路的车辆荷载谱和疲劳车辆模型,基于佛山平胜大桥的动态称重系统采集的多时段车流数据,归类出了车辆 荷载谱的10类代表车型,分析了代表车型的轴距、质量、轴重和超载数据,以及沿不同车道的车辆和轴重分布特性,提出了可用于钢 桥疲劳评估的车辆荷载谱; 以疲劳加载率最大的六轴车辆为原型,基于疲劳损伤等效原则分别提出了桥梁单向重载车道的疲劳车辆 模型和简化疲劳车辆模型。计算结果表明:平胜大桥呈现货运繁重公路的典型特征,车辆日均通行总量达到了45 065 veh,约为 《AASHTO LRFD》定义的日均通行量20 000 veh的2.3倍; 疲劳车辆在全部交通流中的比例为51.6%,为《AASHTO LRFD》定义的20.0% 的2.6倍; 货车占疲劳车辆总数的45.2%,主要分布于重载车道,而且通行货车超载比例占到相应车型的30%~70%,最大超载货车达到 了132.5 t; 两轴货车超载率为29.0%,等效质量达到17.5 t,后轴等效轴重达到12.1 t,因而不能忽略两轴货车的疲劳加载贡献。对 比《AASHTO LRFD》五轴标准疲劳车辆模型(前轴轴重为2.6 t,中间双联轴和后面双联轴的单轴轴重均为5.4 t)和简化标准疲劳车辆 模型(前轴为2.6 t,中轴和后轴均为10.8 t),提出的六轴单向疲劳车辆模型总质量为33.1 t,前轴轴重为3.6 t,中间双联轴和后面三 联轴的单轴轴重均为5.9 t; 简化单向疲劳车辆模型的前轴轴重为3.6 t,中轴和后轴分别为11.8、17.7 t; 针对重载车道提出的六 轴疲劳车辆模型总质量达到了36.5 t,前轴轴重为4.0 t,联轴中的单轴轴重均为6.5 t; 对应的重载车道简化疲劳车模型的前轴轴重 为4.0 t,中轴和后轴轴重分别为13.0、19.5 t。
In order to research vehicle loading spectrum and fatigue truck models of heavy cargo highway, the multi-period traffic flow data based on a weight-in-motion system located on Pingsheng Bridge in Foshan were used to present 10 representative vehicle types. The wheelbases, masses, axle loads and overload data of representative vehicle types were analyzed, the distributions of vehicle types and axle loads on each lane were studied, and vehicle loading spectrum was proposed to evaluate the fatigue performance of steel bridge. The six-axle truck with the largest fatigue loading rate was taken as prototype, the fatigue truck model and simplified fatigue truck model of unidirectional heavy load lane of bridge were proposed based on the equivalent rule of fatigue damage. Calculation result shows that Pingsheng Bridge presents the typical features of heavy cargo highway, the average daily traffic is 45 065 veh and 2.3 times as large as 20 000 veh in AASHTO LRFD. The proportion of fatigue vehicles is 51.6% in all traffic flow and 2.6 times as large as 20.0% in AASHTO LRFD. The proportion of trucks is 45.2% in all fatigue vehicles, they mainly distribute on heavy lanes, overload trucks accounts for 30%-70% of corresponding vehicle types, and the maximum mass of overload truck reaches 132.5 t. The overload rate of two-axle trucks is 29.0%, the equivalent mass is 17.5 t, and the equivalent mass of rear axle is 12.1 t, therefore, the fatigue loading effect of two-axle trucks should not be ignored. Compared with AASHTO LRFD's five-axle standard fatigue vehicle model(the front axle load is 2.6 t, and the single axle loads of mid and rear two-axle group are 5.4 t)and the simplified fatigue vehicle model(the front axle load is 2.6 t, and the mid axle load and rear axle load are 10.8 t), the total mass of
Gennadiy Yun,Victoria Gyrych
Proceedings of National Aviation University , 2011,
Abstract: . Lack of system research done by domestic and foreign scientists in the field of optimal cargostraffic distribution problem in Air Cargo Terminal, proves necessity of investigation and optimization of thisprocess. Mathematical models and algorithms of optimal problem solving for air cargos distribution inwarehouses on the basis of established functional dependence between freight flow stowage in warehousesand transport vehicle loading (unloading) processes are presented in the article.Keywords:algorithms, dimensions of air cargo terminal, effectiveness of loading-unloading processes,freight flow, models.
Multi-mass trammel pendulum model of fluid lateral sloshing for tank vehicle

- , 2018,
Abstract: 为深入研究液罐车整车侧向动力学行为,探讨了椭圆形(圆形)截面罐体等效机械液体侧向晃动模型; 基于计算流体动力学(CFD)软件FLUENT,评价了椭圆规摆(TP)模型的预测精度,分析了充液比、罐体截面椭圆率和激励频率对模型预测精度的影响; 提出了广义多质量TP模型,通过合理分配液摆各部分质量及其间距来适应罐体截面椭圆率和充液比的变化; 基于Lagrange方法推导了广义多质量TP模型动力学方程,给出了双质量TP(DMTP)模型的质量比和质量间距参数的获取方法和拟合表达式,并采用CFD方法评价了DMTP模型的预测精度。分析结果表明:由TP模型得到的晃动力矩总体较CFD方法的小,随着充液比和激励频率的增加,预测误差变大,充液比由30%增加到80%时,峰值晃动力矩预测误差由15%增加到65%左右,这主要是由于TP模型是在液体小初始倾斜角自由晃动条件下拟合所得,当充液比和晃动频率较高时,液摆的摆臂长度和参与晃动的液体质量都小于实际情况; DMTP模型在大部分充液比、罐体截面椭圆率和激励频率条件下都有相对稳定且较高的预测精度,激励频率分别为0.2、0.3 Hz时,DMTP模型的最大晃动力矩预测均方根误差均值和标准差分别比TP模型小54.2%、43.9%和45.1%、31.2%,预测精度较TP模型有明显提高,特别是能够较好地弥补TP模型在高充液比时预测误差较大的不足。
To deeply investigate the lateral dynamics of tank vehicle, the equivalent mechanical model of fluid lateral sloshing for a tank with elliptical(circular)sectional shape was studied. The predicting precision of the trammel pendulum(TP)model was evaluated by the computational fluid dynamics(CFD)software FLUENT, and the effects of fill level, tank sectional ellipticity, and excitation frequency on the model's predicting precision were analyzed. A generalized multi-mass TP model was proposed, the mass and distance between each part of fluid pendulum were reasonably distributed to adapt to the variations in tank sectional ellipticity and fill level. The dynamics equation for the generalized multi-mass TP model was derived based on the Lagrange approach. The method to determine the parameters of mass ratio and distance between the two masses, and the fitting formulas of double mass TP(DMTP)model were presented. The predicting precision of the proposed DMTP model was evaluated by the CFD method. Analysis result shows that the sloshing moment gained from the TP model is generally less than that computed by the CFD method, and the predicting error generally increases as the fill level increases. The predicting error of the peak sloshing moment increases from 15% to 65% when the fill level increases from 30% to 80%. This is mainly because the TP model is fitted under the conditions of small initial fluid incline angle and free sloshing. When the fill level and sloshing frequency are relatively high, both the length of pendulum arm and the sloshing fluid mass are less than the actual cases. The proposed DMTP model presents a relatively stable and high predicting precision in most conditions of fill levels, tank sectional ellipticities and excitation frequencies. Comparing with the TP model, when excitation frequency is 0.2 and 0.3 Hz, respectively, the mean value of the root mean square error(RMSE)of the predicted maximum sloshing moment in the DMTP model decreases by 54.2% and
An ant colony optimization algorithm for vehicle routing problem with cargo coefficient

TANG Jia-fu,KONG Yuan,PAN Zhen-dong,DONG Ying,
,孔 媛,潘震东,董 颖

控制理论与应用 , 2008,
Abstract: A distribution network between one warehouse and multiple retailers is considered.A model named weighted vehicle routing problem(VRP)is built.Being contrary to many other VRP models,the weight loaded in a vehicle through a route between two customers is considered as an important factor of system cost when a routing decision is made.With this method,the retailers with larger demands will have priority to be visited earlier.Finally,an ant colony optimization algorithm named PMMAS(partition based max-min ant system)combined with a special partition method is proposed to solve this model.Some illustrative examples are introduced to test the efficiency of the PMMAS,and comparison analysis is conducted with commonly used heuristic algorithms for vehicle routing problem.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.