DJJ_2型动力车电制动力的运用分析

针对“中华之星”号DJJ_2型动力车在试运行过程中出现的车轮擦伤现象,借鉴国外运行经验,对其电制动特性、电制动力进行分析,并提出相应改进措施。

极不均匀载荷条件下列车的牵引力和电制动力分配方案

钢轮钢轨式轨道交通车辆的动力最终来源是车轮和轨道之间的相互作用力——黏着力,列车的黏着力与其质量直接相关。地铁的客流特点决定了地铁列车整车的质量分布是相对均匀的,但是上海浦东机场线因其特殊的运营需求,可能出现不同车厢之间载荷极不均匀的工况,针对此特殊工况在既有的牵引力和电制动力分配策略的基础上,优化了列车牵引力和电制动力的分配方案,避免了因车辆载荷不均衡所导致的车轮空转和打滑的问题,并最大限度地减小了牵引力和电制动力的损失。

重载机车电制动力对踏面剥离的影响研究

车轮踏面剥离是机车车辆运用中最常见的故障,对机车车辆运营安全性有较大影响。车轮踏面剥离是一个比较复杂的失效种类,导致其剥离的因素很多,无论是车轮材质本身,还是运用工况的变化或机车车辆的结构设计等方面的缺陷,均有可能导致剥离现象的产生。实测六轴、八轴电力机车车轮踏面的状态,提取主要特征,分析了轮轨受力特性。并从轮轨动力学的角度,通过仿真分析了机车电制动力对轮轨纵向蠕滑力和纵向蠕滑率的影响,从而证明有效降低电制动力可以减缓或消除车轮踏面剥离,为解决车轮踏面剥离问题提供了一定的参考。

增大高速区域电制动力的方法

在列车进一步提速的情况下,为减轻机械制动的负担,减少换闸瓦等维护工作量,必须增大电制动力。介绍运用接入电阻以增大高速区电制动力的方法及其试验结果。

增大高速区电制动力的方法

针对现有电力机车高速区电制动力下降,导致车辆维修费用增加问题,提出了2种解决办法,即在牵引逆变器和电机绕组间串接电阻或电容,来提高电制动力和改善功率因数,并从理论和实践的角度作了充分的论证。对电阻短路时引起的电流和转矩变动进行了试验分析,并提出了解决方法。

基于转鼓转速传感的中低速新能源汽车联合制动系统控制方法

中低速新能源汽车是常见的交通工具,但是其制动控制存在响应时间长、控制效果差的问题,设计一种基于转鼓转速传感的中低速新能源汽车联合制动系统控制方法。首先,构建基于转鼓转速传感的中低速新能源汽车动力学方程,采集传感信息,然后,考虑开环控制容易导致控制系统的稳定性和鲁棒性差的问题,基于转鼓转速传感的联合制动系统传递函数推导出开环、闭环双传递函数,最后,根据系统传递函数,设计PID控制器的参数,通过PID控制器输出电-液联合制动控制信号,实现汽车联合制动系统控制。实验结果表明:所提方法的速度-位移曲线与现实速度-位移曲线基本一致,加速误差在-0.5 m/s2~0.5 m/s2范围内,平均制动控制响应时间为0.075 s,具有良好的制动控制能力。

基于永磁牵引系统的地铁列车空气制动力分配研究

为了充分发挥地铁列车永磁牵引系统节能的优势,降低列车制动控制的复杂度、保证其可靠性,文章以长沙轨道交通5号线列车为例,设计了一种基于永磁牵引系统的地铁列车空气制动力分配方案:当列车单轴、双轴或不同车三根轴及以上电制动故障时,保留故障车其他轴的电制动力,不足的制动力由拖车上的空气制动力平均分配;当列车同车三根轴及以上电制动故障时,切除故障车的电制动力,不足的制动力由拖车和故障车上的空气制动力平均分配。

基于主从控机车异步控制的重载列车操纵优化

为研究两万吨列车在长大下坡道运行时缓解产生的较大车钩力问题,使用列车空气制动与纵向动力学联合仿真系统(TABLDSS),分析主、从控机车电制动力的异步控制对缓解时最大车钩力的影响,并提出一种利用主、从控机车的异步控制来减小最大车钩力的优化方案。选取某重载铁路的两段路,优化前后结果表明:第一段路列车的最大拉钩力降低8.2%;最大压钩力降低52.3%;第二段路列车的最大拉钩力降低12.1%,最大压钩力降低49.9%。说明缓解时增加主控机车的电制动力,减小从控机车的电制动力,可以减小列车所受到的最大拉钩力;出现最大拉钩力后10 s内降低主、从控机车电制动力可以减小列车所受到的最大压钩力。

Vibration analysis of maglev three-span rigid frame bridge considering magnetic force

The dynamic interaction between the maglev vehicle and the three-span rigid frame bridge is discussed. With the consideration of magnetic force, the interaction model is developed. Numerical simulations are performed to study the dynamic characteristics of the bridge during vehicle movement along the bridge. The results show that a reasonable value of the linear stiffness ratio of columns to beams is between 2. 0 and 3.0. The dynamic responses of the bridge are aggravated with the decrease in bending rigidity and the increase in vehicle speed and the span ratio of the bridge. It is suggested that a definite way is to control impact coefficients and acceleration in the dynamic design of the bridge. It is unsuitable to adopt the moving load model and the moving mass model in the design. The proposed results can serve in the design of high-speed maglev three-span rigid frame bridges.

Wide speed range for traction motor in braking force of electric braking control system

A vehicle stopping method using an electric brake until a traction motor is stopped is studied. At the moment of vehicle stop, electric brake is changed to control mode where torque is reduced at a low speed. Gradient is controlled by estimating the load torque of motor, thereby traction motor is not rotated after stop. In addition, coasting operation and brake test are performed from normal-opposite operation and start using a small-scale model comprising the inertial load equipment and the power converter. Further, traction motor is made to be equipped with a suspension torque. Pure electric braking that makes traction motor stop by an air brake at the time of stop is also implemented. Constant torque range and constant power range are expanded during braking so that braking force is secured with the electric brakes even in high speed region. Therefore, vehicle reduction effect can be expected by reducing parts related with an air brake which is not used frequently by using a pure electric brake in the M car in wide speed region. Further, maintenance of brake system can be reduced. Besides, ride comfort of passenger in the electric rail car, energy efficiency improvement, and noise reduction effect can be additionally expected. Further, an improved brake method that uses only an electric brake till motor stop is proposed by comparing those in the blending brake that uses an air brake while reducing brake torque at vehicle stop.

A Tentative Analysis of the Use of Potential by Commercial Bank in Controlling Credit Scale

This article brings forward the conception of potential and filed potential in bank's competition under the inspiration of law of electric current in electrodynamics. It discusses the impact of potential shifting on commercial bank's credit scale and builds up a model for commercial bank to control the scale by credit pricing and risk policy in a dynamic way, and also gives some advice to domestic commercial bank for improving loan business, aiming to settle down the existing credit management problems.

Supervisory control of the hybrid off-highway vehicle for fuel economy improvement using predictive double Q-learning with backup models

This paper studied a supervisory control system for a hybrid off-highway electric vehicle under the chargesustaining(CS)condition.A new predictive double Q-learning with backup models(PDQL)scheme is proposed to optimize the engine fuel in real-world driving and improve energy efficiency with a faster and more robust learning process.Unlike the existing“model-free”methods,which solely follow on-policy and off-policy to update knowledge bases(Q-tables),the PDQL is developed with the capability to merge both on-policy and off-policy learning by introducing a backup model(Q-table).Experimental evaluations are conducted based on software-in-the-loop(SiL)and hardware-in-the-loop(HiL)test platforms based on real-time modelling of the studied vehicle.Compared to the standard double Q-learning(SDQL),the PDQL only needs half of the learning iterations to achieve better energy efficiency than the SDQL at the end learning process.In the SiL under 35 rounds of learning,the results show that the PDQL can improve the vehicle energy efficiency by 1.75%higher than SDQL.By implementing the PDQL in HiL under four predefined real-world conditions,the PDQL can robustly save more than 5.03%energy than the SDQL scheme.

Support vector machine based nonlinear model multi-step-ahead optimizing predictive control

A support vector machine with guadratic polynomial kernel function based nonlinear model multi-step-ahead optimizing predictive controller was presented. A support vector machine based predictive model was established by black-box identification. And a quadratic objective function with receding horizon was selected to obtain the controller output. By solving a nonlinear optimization problem with equality constraint of model output and boundary constraint of controller output using Nelder-Mead simplex direct search method, a sub-optimal control law was achieved in feature space. The effect of the controller was demonstrated on a recognized benchmark problem and a continuous-stirred tank reactor. The simulation results show that the multi-step-ahead predictive controller can be well applied to nonlinear system, with better performance in following reference trajectory and disturbance-rejection.

Kinetics and Modeling of Chemical Leaching of Sphalerite Concentrate Using Ferric Iron in a Redox-controlled Reactor

This work presents a study for chemical leaching of sphalerite concentrate under various constant Fe3+ concentrations and redox potential conditions. The effects of Fe3+ concentration and redox potential on chemical leaching of sphalerite were investigated. The shrinking core model was applied to analyze the experimental results. It was found that both the Fe3+ concentration and the redox potential controlled the chemical leaching rate of sphalerite. A new kinetic model was developed, in which the chemical leaching rate of sphalerite was proportional to Fe3+ concentration and Fe3+ /Fe2+ ratio. All the model parameters were evaluated from the experimental data. The model predictions fit well with the experimental observed values.

Dynamic Analysis of Micro-machined Diamagnetic Stable Permanent Magnet Levitation System

A novel micro-machined diamagnetic stable.levitation system （MDSLS） which is composed of a free permanent magnetic rotor, a ring lifting permanent magnet and two diamagnetic stabilizers was presented. The static and dynamic stable characters of MDSLS were analyzed. The coupled non-linear differential equations were used to describe six-degree-of-freedom motion of the levitated rotor, and the equivalent surface current and combined dia- magnetic image current method were utilized to model the interaction forces and torques between the lifting perma- nent magnet and rotor permanent magnet and also between the rotor permanent magnet and diamagnetic sub- strates. Because of difficulty to get analytical solution, the numerical calculation based on Runge-Kutta method was used to solve the dynamic model. The vibration frequencies were identified b~ fast Fourier transform （FFT） analysis. According to their resonance characteristics and parameters, the translational and angular dynamic stiff- ness were also calculated. The results show that the levitation of the rotor in MDSLS is stable, and the MDSLS is potential for the application in levitation inertial sensor.

Improved control of intelligent excavator using proportional-integral-plus gain scheduling

Consider the design and implementation of an electro-hydraulic control system for a robotic excavator, namely the Lancaster University computerized and intelligent excavator (LUCIE). The excavator was developed to autonomously dig trenches without human intervention. One stumbling block is the achievement of adequate, accurate, quick and smooth movement under automatic control, which is difficult for traditional control algorithm, e.g. PI/PID. A gain scheduling design, based on the true digital proportional-integral-plus (PIP) control methodology, was utilized to regulate the nonlinear joint dynamics. Simulation and initial field tests both demonstrated the feasibility and robustness of proposed technique to the uncertainties of parameters, time delay and load disturbances, with the excavator arm directed along specified trajectories in a smooth, fast and accurate manner. The tracking error magnitudes for oblique straight line and horizontal straight line are less than 20 mm and 50 mm, respectively, while the velocity reaches 9 m/min.

Development of Multi-Fingered Prosthetic Hand Using Shape Memory Alloy Type Artificial Muscle

A new prosthetic hand with a fixed thumb and four fingers actuated by Shape Memory Alloy （SMA） type artificial muscle has been developed in this paper. Different from typical geared motor, SMA actuator is lightweight and silent, however shows a little short stroke and small attracting force per each unit. In order to achieve enough output force and motion range of each finger, multiple SMA type artificial muscles with special device which facilitates enough length are equipped in the hand. The fundamental properties of the SMA type artificial muscle including output force and electrical response were determined experimentally and considered for the design of hand mechanism. Besides, the structure of each finger and whole system has been designed based on observation of human hand. The electrical hardware to control multiple shape memory alloy type artificial muscles has been also developed. Finally, the usefulness of the prosthetic hand has been investigated through experiments for grasping several types of objects.

Novel flexible hybrid electric system and adaptive online-optimal energy management controller for plug-in hybrid electric vehicles

In order to achieve the improvement of the driving comfort and energy efficiency,an new e-CVT flexible full hybrid electric system(E2FHS) is proposed,which uses an integrated main drive motor and generator to take the place of the original automatic or manual transmission to realize the functions of continuously variable transmission(e-CVT).The design and prototype realization of the E2FHS system for a plug-in hybrid vehicle(PHEV) is performed.In order to analyze and optimize the parameters and the power flux between different parts of the E2FHS,simulation software is developed.Especially,in order to optimize the performance of the energy economy improvement of the E2FHS,the effect of the different energy management controllers is investigated,and an adaptive online-optimal energy management controller for the E2FHS is built and validated by the prototype PHEV.

Dynamic balancing with rotating radial electromagnetic force

A method of producing rotating radial electromagnetic force with a separable structure is proposed, and an experimental model was designed on which open loop vibration control experiments were carried out. Experimental results prove that the electromagnetic force designed has a constant magnitude and an uniform speed, and the idea of using an electromagnetic force as an active control in automatic balancing is correct in principle, and practicable in engineering.