Contribution of metal vapor mass at periphery part of pulsed arc to electromagnetic force in weld pool

The arc welding has been used in various welding methods because it is inexpensive and high in strength after welding. However, it is a problem that accidents such as collapse of the bridge occur because of the welding defects. The welding of low cost and high productivity is required without the welding defects. The pulsed TIG welding is inexpensive and capable of high‐quality welding. The electromagnetic force contributing to penetration changes because the transient response of arc temperature and iron vapor generated from anode occurs. However, the analysis of pulsed TIG welding with metal vapor has been elucidated only metal vapor concentration near anode with transient phenomenon and heat flux. Thus, the theoretical elucidation of penetration depth with control factor has not been researched. In this paper, the contribution of metal vapor mass at the periphery part of pulsed arc to the electromagnetic force in the weld pool is elucidated. As a result, the iron vapor mass at periphery part decreased with increasing the frequency. The iron vapor was stagnated at axial center within one cycle. The electromagnetic force to the penetration depth direction in weld pool increased at axial center. Therefore, the metal vapor mass at periphery part plays an important role for the electromagnetic force increment at axial center.     

直线感应电机的有限元仿真与分析

分析了用于城市轨道交通的直线感应电机的结构特征及其等效电路,阐述了相关参数的计算方法,包括电机励磁电抗、效率、功率因素等,并应用Ansoft有限元软件,对一台直线感应电机样机进行了电磁分析。通过有限元仿真与分析,得出了电机内部电磁场的分布特点和规律,研究结果为直线感应电机电磁设计提供了理论基础。同时,仿真结果对今后电机控制系统的设计有着重要意义。     

医用玻璃的熔融特性研究

医疗废物中有许多低熔点的医用玻璃。医疗废物在回转窑焚烧炉内燃烧时,炉内的高温会将医用玻璃熔化,熔融的玻璃会导致回转窑炉的结渣。用分析纯来代替玻璃组分,研究医用玻璃的熔融特性。实验结果显示,不同化学组分对熔融温度有不同的影响,SiO2能够提高医用玻璃的熔融温度,B2O3和碱金属氧化物(Na2O、K2O)会大幅降低医用玻璃的熔融温度,而碱土金属氧化物(CaO、BaO)和Al2O3会使医用玻璃的软化温度升高,却能使流动温度降低。简化Taylor公式,得出了医用玻璃熔融温度的预测函数。计算结果显示,熔融温度的预测值和实验值吻合较好。     

双槽单相电容直线异步电动机电磁推力分析

为了研究和开发一种新的、结构简单的直线执行装置,对双槽单相电容直线异步电机的电磁推力进行了分析研究。此电机初级采用变压器E型铁心、集中绕组、两个槽和一对极,最大的特点是结构简单,且非磁性次级的采用避免了纵向拉力所附加产生的横向摩擦力。通过搭建试验平台,得出了电机的各项基本参数和电磁推力,为进一步电机优化形成产品提供依据。     

Revolving magnet wheels with permanent magnets

A new type of actuator with both magnetic levitation and linear drive is proposed. The actuator, called magnet wheel, has a rotating magnetic field obtained by revolving permanent magnets with high coercivity mechanically. The induction repulsive-type magnetic lift force with self-stabilization can be obtained by linking the rotating flux to a conducting plate. The induced simultaneous drag torque, which causes power loss, is used to obtain thrust in two proposed ways. These are called “tilt type” and “partial overlap type,” respectively. In the tilt type, the magnet wheel is tilted against the surface of a conducting plate. In the partial overlap type, the magnet wheel operates near the edge of a conducting plate. In this paper, the fundamentals of the structure of proposed magnet wheels are described. The basic characteristics at parallel to the conductor are shown by using a numerical three-dimensional electromagnetic analysis and measured results. The generation of both lift force and thrust in tilt type and partial overlap type magnet wheel are proved by experiments, respectively.     

Relationship between magnetic poles and characteristics of revolving permanent‐magnet type magnet wheels

The authors earlier proposed a revolving permanent‐magnet type wheel called the “magnet wheel,” which has the functions of both induction repulsive magnetic levitation and thrust. In this paper, the relationship between magnetic poles and lift force or thrust characteristics is examined to investigate the performance. Five types of magnet wheels are discussed in an experimental study and four more types are used in a theoretical study with three‐dimensional numerical analysis. The following parameters are considered: magnetomotive force (mmf) of a permanent magnet; thickness of the magnet in the magnetizing direction; total volume of magnets; fundamental factor; distortion factor of the space mmf distribution of poles; pole pitch; diameter of magnet wheel; mechanical clearance; and thickness and resistivity of conducting plate. The results show the following: 1. The lift force per unit of magnet volume is approximately proportional to the fundamental factor of the space mmf distribution of the poles. A low degree space harmonic mmf is effective in increasing lift force. 2. The driving power per unit of lift force is almost entirely independent of the configuration of the primary member, including pole arrangement and position relative to the secondary conducting plate, respectively, and depends only on the resistance of the conducting plate. 3. In both the “partial‐overlap type” and “tilt type” magnet wheels, many poles with sufficiently large pole pitch are useful. In the tilt type the use of a small tilt angle is desirable. © 1999 Scripta Technica, Electr Eng Jpn, 128(4): 111–120, 1999     

基于单片机的水下滑翔机控制系统设计

针对水下滑翔机的运动要求和结构特点,提出了一种基于STC单片机的运动控制系统设计方案,该系统通过单片机对滑翔机的运动参数进行采集,根据采集的反馈信号控制重心调节机构,改变滑翔机的运动姿态;控制重浮力调节机构,实现滑翔机的上浮和下潜,最终实现水下滑翔机的运动控制。通过对该系统的仿真和实验分析,验证了控制算法的可行性,为水下滑翔机的后续开发奠定了基础。     

Nonlinear hierarchical control of a quad tilt‐wing UAV: An adaptive control approach

In this paper, a nonlinear hierarchical adaptive control framework is proposed for the control of a quad tilt‐wing unmanned aerial vehicle (UAV). An outer loop model reference adaptive controller with robustifying terms creates required forces to be able to move the UAV on a reference trajectory, and an inner loop nonlinear adaptive controller realizes the required attitude angles to achieve these forces. A rigorous stability analysis is provided showing the boundedness of all the signals in this cascaded controller structure. The development and the stability analysis of the controller do not use any linearizations and use the full nonlinear UAV dynamics. The controller is implemented on a high‐fidelity nonlinear tilt‐wing quadrotor model in the presence of uncertainties, wind disturbances, and measurement noise as well as actuator and structural failures. In this work, in addition to earlier modeling studies, the effect of wing‐angle variations, actuator failures, and structural failures and their effect on the center of gravity of the UAV are rigorously and systematically investigated and reflected in the model. Simulation results showing the performance of the proposed controller and a comparison with the fixed controller used in earlier studies are presented in the paper.     

用粘塑性材料作为传力介质的板料半模成形技术

在传统的板料半模成形工艺中,所使用的传力介质为橡胶、聚胺脂、橡皮囊、油或水等,但它们都有各自的缺点。油或水容易泄漏,容框内压力难于进一步提高,尤其在成形失败时,液体飞溅不仅污染环境,而且累及操作者;橡皮囊成形机价格昂贵,且难以实现深拉延和深弯曲;而采用聚氨酯或橡胶做为软模时,还受到自身变形条件限制,难以成形局部变形量较大零件。基于此,作者探索性地进行了用粘塑性材料作为传力介质来进行板料成形的研究。通过大量实验,探索出了理想的粘塑性传力介质应具备的条件,并寻找到了一种合适的粘塑性传力介质。用这种介质,在同一容框内,通过更换不同凸模生产了五种不同的特形零件。实验表明,用该方法可使筒形件的拉延比达到0.38,最大变薄率小于10%,零件形状误差,表面质量均不低于充液拉延,甚至可以很方便地成形法兰与拉延方向不垂直的零件。     

基于三维有限元的静态连接梅花触头短路暂态电动力分析

针对梅花触头电动稳定性设计与接触失效机理分析,采用三维有限元方法建立了梅花触头电动力计算模型,基于该模型分析计算了短路负荷条件下的梅花触头与导体的电动力暂态变化过程.通过与其它计算方法对比分析,结果表明该计算模型可以克服经验公式法无法准确考虑触指结构的缺点,能够较为准确计算不同触指结构的梅花触头短路电动力分布.基于该模型分析了梅花触头短路电动力的影响因素,分析结果表明短路电动力增大引起的梅花触指接触压力减小是造成梅花触头失效的一个重要原因,增大接触压力对提高梅花触头电动稳定性的作用有限,增加触指片数和减小触指半径是提高梅花触头电动稳定性的有效途径.     

Rail brake system using a linear induction motor for dynamic braking

One type of braking system for railway vehicles is the eddy current brake. Because this type of brake has the problem of rail heating, it has not been used for practical applications in Japan. Therefore, we proposed the use of a linear induction motor (LIM) for dynamic braking in eddy current brake systems. The LIM reduces rail heating and uses an inverter for self excitation. We estimated the performance of an LIM from experimental results of a fundamental test machine and confirmed that the LIM generates an approximately constant braking force under constant current excitation. At relatively low frequencies, this braking force remains unaffected by frequency changes. The reduction ratio of rail heating is also approximately proportional to the frequency. We also confirmed that dynamic braking resulting in no electrical output can be used for drive control of the LIM. These characteristics are convenient for the realization of the LIM rail brake system. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(2): 29–38, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21209     

基于微机电系统加速度计的杆塔倾斜检测装置的开发

输电线路杆塔倾斜是处于不良地质区(采空区、滑坡区、高盐冻土区等)的输电线路随时会出现的严重故障,为了及时发现杆塔倾斜并修复,需要对杆塔的状态进行实时监测。依据重力加速度测量值计算倾斜角原理,设计开发了一种输电线路杆塔倾斜检测装置,采用基于微机电系统的三轴加速度计ADXL345作为传感元件进行数据采集,采用含有无线射频电路及Zigbee协议栈的STM32W108片上系统作为中央处理器进行加速度采样数据处理,并经Zigbee网络传送至上位机,实现了杆塔倾斜角的实时检测。     

Optimized Energy‐Saving Speed Profile in Linear‐Motor Railway System

The most striking characteristic of linear‐motor railway system is that the structure consists of a primary and secondary linear induction motor (LIM). The primary side of the LIM is installed in a rolling stock, and the secondary side of LIM is installed on the track. The magnetic attractive vertical force produced by the LIM increases the running resistance since this force is in the same direction as the gravitational force due to which rolling stocks gain weight virtually from the track side of view. In addition, the efficiency of the LIM has different characteristics of efficiency compared with the rotary motor. Previous studies have focused on the design method of LIM to improve motor efficiency and decrease energy consumption. However, it is a well‐known fact that this kind of approach requires hardware renewal which requests large amount of investments. The purpose of this study is to analyze these characteristics of LIM effects and design the optimal speed profile to minimize the energy consumption as a linear‐motor railway system. This smart and economic energy‐saving approach is based on the optimization of speed profiles of the linear‐motor railway system using dynamic programming.     

新型磁流体水平传感器的研究与设计

磁流体作为一种新型的功能材料,兼具流动性和磁性,并具有许多独特的性质。利用永磁体在磁流体中受到二阶浮力可悬浮的特性,设计了一种新型的一维磁流体水平传感器。该磁流体水平传感器由外壳、芯体、磁流体和永磁体构成,芯体采用永磁体和铁芯组合而成。将芯体置入外壳中,在芯体两端部永磁体与外壳内壁间注入磁流体,磁流体产生二阶浮力使芯体径向稳定悬浮于外壳中,外壳端部永磁体与芯体端部永磁体间的磁斥力提供芯体轴向的回复力使芯体处于轴向平衡位置。当传感器偏离水平位置时,芯体将产生轴向位移并反映出倾角的大小。芯体中的铁芯和外部的电感线圈,可实现芯体位移的亚微米级检测。理论分析了其原理,设计并制作了实验样机。实验结果表明,-10~10°倾角范围内,检测分辨率可达0.03°。     

典型汽车螺纹板成型的数值模拟与工艺改进

传统的螺纹板成型工艺通过焊接将螺母固定在板料上,其缺点是联结强度和定位精度不高,成型效率低,外表不美观.采用板料一体成型的新方法,通过板料拉深、整型、冲孔、镦挤出凸台,这种方法虽弥补了传统工艺的不足,但成型困难.为了在工艺设计阶段及时发现缺陷,采用有限元数值模拟对板料一体成型过程进行预测与评估,提出工艺改进方案以消除缺陷,并且给出了成型力以选择合适的压力设备.     

Stability Criterion of Biped Robot on Rough Terrain

This paper presents a stability criterion for biped robots on rough terrain. On rough terrain, which is not perpendicular to gravity, a robot may not fall even though its center of mass is out of the area of the supported polygon defined by the conventional VHP (virtual horizontal plane) method. This is because there exists a certain force opposing the torque that causes the robot to fall down. We propose a new measure for strictly judging the limit of falling considering all the forces acting on the contact points. Numerical simulations and experimental results are also shown, which verify the proposed method.     

确定无心感应熔炼炉熔液表面形状的电磁场边界元分析法

本文用轴对称横向磁场(TM)模型的矢量磁位的外部区域边界积分方程,结合阻抗边界条件,得到了描述无心感应熔炼炉电磁场问题的边界元方程。根据熔炼金属液面的平衡条件,提出了确定熔炼金属表面形状的边界元迭代算法。运用这一算法进行了实例计算,计算结果与模拟实验所测量的结果十分吻合。对2t工频熔铝炉的计算,也得到了比文献更接近于实测数据的结果。     

A compensation method for the end effect of a linear induction motor

For the end effect of a linear induction motor (LIM), the authors propose a new concept that the end effect can be compensated for only by the supply of secondary current synchronized with the current of the LIM in front of the entry end of the LIM, without considering the flux density distribution in the LIM primary region. As a concrete method to supply the secondary current in front of the LIM, the authors propose the rotator with rare‐earth‐type permanent magnets which has a strong flux density without ohmic loss, and does not cause the power factor problem even for the influence of end effect. The results of analytical study on the numerical example of LIM designed for subways are as follows. This method can make the flux density and thrust density distribution in the LIM primary region almost entirely agree with those of the case without end effects. This method can compensate for the thrust, power factor, and efficiency of the LIM at the rated speed to coincide with the characteristics without end effect. There is no problem in the slip characteristic curves of the LIM with the compensator, although the compensator only rotates synchronizing with the frequency of the LIM. The effect of compensation becomes large in the lower slip. The force to rotate the compensator is very small in the suitable design. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(3): 58–67, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10132     

Edge effect and independently supplied slot currents in tubular linear induction motors

The linear induction motor (LIM) is divided structurally into the flat and the tubular-type. This paper examines one kind of tubular linear induction motor whose primary configuration consists of four pieces of a flat-type core. We call this type of motor “the square tubular LIM.” The square tubular LIM has various merits of the cylindrical tubular LIM in addition to those of the usual flat-type LIM. The two remarkable features of the square tubular LIM that the flat-type LIM does not have are as follows. The first feature is that it has no edge effect, and the second is that the normal force in secondary conductor is cancelled by that of the opposite side of the secondary conductor. In comparison with the cylindrical tubular LIM, moreover, the square tubular LIM is easy to manufacture and maintain. The tubular LIM also has a feature that its primary winding is a kind of ring winding. Thus we can supply independently the primary current in each slot and hence easily obtain various winding schemes. Finally, the features of the square tubular LIM are studied. After numerically analyzing an experimental model, the motor is driven by the independently controlled slot currents, resulting in the expected performance.     

电磁弹射装置中线圈受力与电流相位的关系

为提高发射效率和速度,分析了电磁弹射实验装置中电流相位的关系及决定电磁力性质的主要因素。通过改变放电电路参数及结构,获得了不同放电条件下的电流曲线,并计算出安培力的曲线,总结了影响电磁弹射实验装置中线圈相互作用力性质和作用时间、大小的主要因素,实验表明,在相同的放电条件下,振荡放电较非振荡放电磁场斥力小,作用时间短;振荡放电电路中匝数增加则电动力减少;非振荡放电电路中等效匝数变化对电动力影响不大。