货车连挂方式对万吨重载列车循环制动过程纵向冲动影响分析

基于纵向动力学理论,分析了货车连挂分别采用车钩、两连挂和三连挂的3种万吨重载列车编组在长大下坡道上循环制动过程中的纵向冲动特征,结果表明:3种列车编组循环制动周期内车钩力和加速度沿列车方向分布规律一致,其最大拉钩力和最大压钩力均出现在列车中部,最大加速度出现在列车端部;列车循环制动过程中的最大车钩力出现在制动缓解后,车钩力呈现出"先拉后压"的趋势;制动初速对循环制动过程中的纵向冲动影响较小,其纵向车钩力和加速度均随车钩间隙增大而增大。实际运用中应根据线路条件合理搭配使用牵引杆,兼顾其启动和曲线通过能力。     

典型线路下重载机车胶泥缓冲器泄漏故障分析

针对典型线路下重载机车使用的缓冲器QKX100出现的胶泥泄漏现象,使用铁科院纵向动力学计算软件进行典型线路下重载货运列车的纵向动力学计算;结合胶泥芯子的结构原理,分析钩缓系统故障产生的原因。分析结果表明:在持续的陡坡线路上,变坡度会引起车钩力的剧烈变化,而在进行循环制动时,列车的中后部出现较大纵向冲动;而在此种线路条件下,QKX100弹性胶泥缓冲器的作用也越频繁,因此缓冲器动密封圈的磨损就会加大,胶泥泄漏的也就越大。为了改善缓冲器工作状态,应采用适当的机车操作、合理的列车编组以及更严格的缓冲器生产管控。     

GMC16钢轨打磨车牵引杆装置改进设计

牵引杆装置是打磨A车和B车连接部位的关键部件,其强度和安装精度直接影响精准打磨的品质优劣。通过利用三维软件和有限元软件对牵引杆装置进行建模和强度分析,并依据车辆钩缓的强度设计规范,设计合理安装精度,达到改善牵引杆装置整体强度的目的。以此为依据进行牵引杆装置的实际生产制造和安装运行试验,实现了整车的打磨精度和打磨效率的提高;同时,对降低牵引杆装置的生产制造成本,提高整车安全运行有重要的意义。     

不同车钩组合方式对列车纵向冲动的影响

车钩缓冲装置传递车辆之间的纵向作用力并缓和车辆之间的冲击力,对于改善车辆受力状况和运行性能具有非常重要的意义.利用空气制动仿真系统与三维空间耦合动力学仿真系统联合仿真,将普通车钩与拉杆式车钩进行编组,分析了列车分别由以下三种情况下连接的纵向车钩力:普通车钩、普通车钩与拉杆式车钩组合、拉杆式车钩.对比三种编组,提出一种相...     

铁道车辆车钩缓冲系统常见故障与检修

铁道车辆车钩缓冲装置主要由车钩、缓冲器、钩尾销、钩尾框和前后从板等组成。车钩缓冲系统的作用是实现车辆与车辆之间的连接,同时担任着传递并且缓和列车行进中出现的各种纵向冲击力。分别从钩体、钩舌、钩尾框、缓冲器等四个方面阐述了车钩缓冲装置的常见故障,分析了各部位故障产生的原因,给出了对应故障的预防及处理措施。在故障的成因分析中,制造工艺技术方面的缺陷或误差占有很大比例。车辆在使用过程中的定期检修,可以避免绝大部分车钩系统故障的产生。     

朔黄铁路重载列车线路适应性仿真研究

为了明确重载列车对朔黄铁路的适应性,利用"斜楔-弹簧"简化方法建立了摩擦式缓冲器模型。模型仿真与实测数据的对比结果具有较高的一致性,表明该缓冲器模型可有效模拟缓冲器动态行为。基于实验数据拟合得到的经验公式,建立了列车空气制动模型并验证了模型的正确性。通过动力学仿真的方法,分析了重载列车在朔黄铁路上运行的全程车钩力,并研究了列车在坡道上的纵向动力学特性。结果表明:几次较大车钩力发生时,列车均位于下凹型变坡道上;列车在变坡道紧急制动的最大车钩力大于平直道。理论计算表明,变坡道也会引起车钩压力,是造成纵向冲动变大的原因,坡度差越大产生的车钩力越大,且和列车制动的位置有关。对不同坡度组合的变坡道进行列车制动仿真,验证了纵向冲动是列车制动不同步及坡道共同作用的结果,两部分产生的车钩压力叠加可得到列车在变坡道上制动产生的车钩力。     

基于调车工况的车辆纵向冲击数值模拟研究

根据由车钩缓冲器和心盘组成的铁路货车纵向受力特点,利用Matlab软件建立铁路货车调车冲击的动力学模型,分别研究不同轴重车型、不同刚度阻尼、不同制动阻力状态及不同冲击模式对车辆纵向冲击特性的影响。结果表明,随着我国铁路货车轴重的增大,车钩连挂处、车体与转向架连接处承受的纵向惯性力也随之增大。阻抗特性呈凸型的缓冲器能吸收更多的车辆冲击能量,可适应更大的调车冲击需求。较小的车体底架结构刚度及车体与转向架连接刚度有利于缓和车辆的纵向冲动。被撞车的制动阻力作用会使车辆速度衰减的更快,但也将引起更大的车钩和心盘冲击。冲击模式对车钩和心盘处的冲击影响差异很大,三重冲三重模式下的车钩力最大,三重冲一空模式下的心盘力最大。     

重载列车纵向冲动动力学分析及试验研究

构建基于货车冲击试验数据的缓冲器修正模型模拟缓冲器动力学特性,该模型包含附加阻尼和黏滞摩擦;建立列车空气制动系统多参数数学简化模型表征重载列车空气制动特性;建立以缓冲器动力学模型及空气制动系统模型为基础的列车纵向冲动动力学模型,分析重载组合列车在不同线路条件和制动作用下的纵向动力学行为。结果表明:缓冲器动力学修正模型能较为真实地反映出冲击试验中缓冲器的磁滞特性、尖峰现象及过渡曲线的平稳连接;列车空气制动系统模型能够仿真获得与试验结果相近的制动缸充气特性曲线;采用列车纵向冲动动力学模型仿真获得的大秦线重载组合列车纵向车钩力分布与列车试验值相符。     

列车纵向冲动仿真建模的研究

列车纵向动力学性能是影响列车运行质量和运行安全的重要因素。制动工况变换则是导致列车冲动的主要原因。针对列车在制动工况下的纵向动力学分析，详细论述了列车纵向冲动仿真建模的过程。在Matlab／Simulink仿真模块中，可以计算出每节车体的加速度及车钩力大小，为进一步分析并减轻列车纵向冲动提供了理论基础。     

考虑轮轨黏着变化的货运列车纵向动力学仿真

为研究黏着系数对纵向动力学的影响,建立“1+1”型2万吨重载组合列车计算模型,引入剩余黏着力评价机车牵引力的发挥,研究了黏着限制、曲线黏降及曲线润滑因素影响下的黏着系数变化及其可能引发的列车纵向动力学性能差异。结果表明：在直线牵引工况下列车牵引力提升由于黏着限制而变缓慢,所发挥最大牵引力下降,单机车最大牵引力由380 kN限制到272 kN,拉钩力最大值由800 kN减小到595 kN;在R400 m小曲线牵引工况下,牵引力应从第7档位降低到第6档位,确保机车安全通过;考虑曲线润滑时,牵引档位更低：摩擦因数为0.075和0.10时机车降低档位对应为第2,3档位;摩擦因数为0.125时头部和中部机车通过曲线需分别降低到第4,3档位。由于曲线牵引各工况下发挥的最大牵引力相同,拉钩力最大值差异较小。在纵向动力学计算中,列车牵引力利用和黏着系数变化密切相关,轮轨黏着不足将限制机车能发挥的最大牵引力,进而影响车钩力大小。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

OPTIMIZATION METHOD ON IMPELLER MERIDIONAL CONTOUR AND 3D BLADE

An optimization method for 3D blade and meridional contour of centrifugal or mixed-flow impeller based on the 3D viscous computational fluid dynamics (CFD) analysis is proposed. The blade is indirectly parameterized using the angular momentum and calculated by inverse design method. The design variables are separated into two categories: the meridional contour design variables and the blade design variables. Firstly, only the blade is optimized using genetic algorithm with the meridional contour remained constant. The artificial neural network (ANN) techniques with the training sample data schemed according to design of experiment theory are adopted to construct the response relation between the blade design variables and the impeller performance. Then, based on the ANN approximated relation between the meridional contour design variables and impeller performance, the meridional contour is optimized. Fewer design variables and less calculation effort is required in this method that may be widely used in the optimization of three-dimension impellers. An optimized impeller in a mixed-flow pump, where the head and the efficiency are enhanced by 12.9% and 4.5% respectively, confirms the validity of this newly proposed method.