Performance of Tense Thin-Film Torsion Bar for Large Rotation and Low-Voltage Driving of Micromirror

In this paper, a micromirror device is developed by realizing the large rotation with the low-voltage driving. The maximum rotation angles observed at 5 V are 8.6deg with hysteresis and 7deg with little hysteresis at the static condition. The thin-film torsion bars contribute to decrease in the torsional spring constant. The tension is included for maintaining the compliance in the rotation of the mirror and for increasing stiffness in other movements. The performance of the torsion bar is investigated. The observed hard-spring effect is significant and this can be explained by the combination of the tension and the vertical displacement of the torsion bar     

Theory and experiments of angular vertical comb-drive actuators for scanning micromirrors

We report on the theory and experiments of scanning micromirrors with angular vertical comb-drive (AVC) actuators. Parametric analyses of rotational vertical comb-drive actuators using a hybrid model that combines two-dimensional finite-element solutions with analytic formulations are described. The model is applied to both AVC and staggered vertical comb-drive (SVC) actuators. Detailed design tradeoffs and conditions for pull-in-free operations are discussed. Our simulation results show that the fringe fields play an important role in the estimation of maximum continuous rotation angles, particularly for combs with thin fingers, and that the maximum scan angle of the AVC is up to 60% larger than that of the SVC. Experimentally, a large dc continuous scan angle of 28.8/spl deg/ (optical) has been achieved with a moderate voltage (65 V) for a 1-mm-diameter scanning micromirror with AVC actuators. Excellent agreement between the experimental data and the theoretical simulations has been obtained.     

Gimbal-less monolithic silicon actuators for tip-tilt-piston micromirror applications

In this paper, fully monolithic silicon optical scanners are demonstrated with large static optical beam deflection. The main advantage of the scanners is their high speed of operation for both axes: namely, the actuators allow static two-axis rotation in addition to pistoning of a micromirror without the need for gimbals or specialized isolation technologies. The basic device is actuated by four orthogonally arranged vertical comb-drive rotators etched in the device layer of an silicon-on-insulator wafer, which are coupled by mechanical linkages and mechanical rotation transformers to a central micromirror. The transformers allow larger static rotations of the micromirror from the comb-drive stroke limited rotation of the actuators, with a magnification of up to 3/spl times/ angle demonstrated. A variety of one-axis and two-axis devices have been successfully fabricated and tested, in all cases with 600-/spl mu/m-diameter micromirrors. One-axis micromirrors achieve static optical beam deflections of >20/spl deg/ and peak-to-peak resonant scanning of >50/spl deg/ in one example at a resonant frequency of 4447 Hz. Many two-axis devices utilizing four rotators were tested, and exhibit >18/spl deg/ of static optical deflection at <150 V, while their lowest resonant frequencies are above 4.5 kHz for both axes. A device which utilizes only three bidirectional rotators for tip-tilt-piston actuation achieves -10/spl deg/ to 10/spl deg/ of optical deflection in all axes, and exhibits minimum resonant frequencies of 4096 and 1890 Hz for rotation and pistoning, respectively. Finally, we discuss the preliminary results in scaling tip-tilt-piston devices down to 0.4 /spl times/ 0.4 mm on a side for high fill-factor optical phased arrays. These array elements include bonded low-inertia micromirrors which fully cover the actuators to achieve high fill-factor.     

Two-Axis Gimbal-Less Electrothermal Micromirror for Large-Angle Circumferential Scanning

In this paper, we present the design, simulation, fabrication, and characterization of a two-axis gimbal-less micromirror optimized for large-angle circumferential scanning applications. The single-crystal silicon micromirror consists of novel folded bimorph electrothermal actuators, flexural springs, and a mirror plate coated with a high-reflective Cr/Au thin film. A modified silicon-on-insulator microelectromechanical system process has been applied on the micromirror fabrication. The single-wafer process is based on deep reactive ion etching in order to achieve high fill factor as well as small outline of the micromirror chip. A new mechanical design of bimorph actuators is developed to further increase the mechanical deflection. Both theoretical and experimental results demonstrate that the micromirror can provide a uniform mechanical deflection up to ~9deg with multichannel driving voltages of less than 2.3 V to any angle in full 360deg circumference.     

Fabrication and experimentation of vertical spring-type micromirrorusing shielding screen structure

A vertical spring-type micromirror was fabricated using a shielding screen structure. Unlike the micromirror that was fabricated using only shadow evaporation, the fabricated vertical springs in this case are well defined, using both shadow evaporation and a shielding screen structure. The static and dynamic characteristics of micromirror are measured by means of contact-free optical measurement system. The downward threshold voltage is 16 V and the step response time is 16.8 μs. Images are projected onto a screen using a simple projection system with the fabricated micromirror array     

Electromagnetic 2/spl times/2 MEMS optical switch

This paper presents the design, fabrication, and measurement results of a 2/spl times/2 microelectromechanical systems optical switch. The switch comprises an electromagnet and lensed fibers assembled with a micromachined movable vertical micromirror. The optical switch utilizes the out-of-plane motion of the vertical micromirror actuated by electromagnetic force compared to the comb-driven linear actuation achieved by the electrostatic force. At a wavelength of 1550 nm, the insertion loss of 0.2-0.8 dB and the polarization-dependent loss of 0.02-0.2 dB are measured. The switching time is 1 ms. A novel method of realizing a latchable optical switch using an electromagnetic actuator is also provided and verified. The latch mechanism is based on the latchability of the electropermanent magnet instead of the mechanical one using conventional arch-shaped leaf springs.     

A Varifocal Convex Micromirror Driven by a Bending Moment

A varifocal micromirror is designed and fabricated using silicon micromachining technology. A spherical convex surface of mirror is generated by applying a bending moment to the circumference of micromirror. This method is different from the conventional technique in which a distributed force is exerted on the central area of mirror. On the basis of the theory of materials strength, the deformation of a plate is purely spherical if only a bending moment is applied to the circumference. Spherical surface is well approximated to be a parabola if deflection is small. In order to generate only a bending moment, a force is applied to the plate in the region outside the fulcrum, by which the plate is supported freely in rotation. The proposed mirror was fabricated from a silicon on insulator wafer and a glass plate, which were connected by anodic bonding. The deviation in surface profile of mirror from a parabola was measured with an optical interferometer to be less than 4.7 nm rms in the mirror region inside the 400-mum-diameter fulcrum at the voltage lower than 215 V. The focal length of the fabricated mirror was varied from approximate infinity to 24 mm.     

线束端子角度姿态的视觉检测方法

端子作为线束生产的重要组件,利用视觉成像检测其姿态是汽车智能制造领域的研究课题之一。线束端子旋转角度自动检测设备通常利用机器视觉获取端子的姿态,提出一种线束端子角度姿态的视觉检测方法,利用电机将端子匀速旋转90°,并在旋转过程中连续采集图像,获得端子的旋转图像序列;根据端子旋转过程的成像特点,找到金属面正对的图像帧,并提取ROI图像;以该ROI图像为对象,利用端子模板库进行匹配,判断得到该金属面所属类别,从而计算出端子需要旋转的角度传输给电机。大量实验结果表明,所提出的方法可以有效地识别端子的角度姿态,并且快速准确地计算旋转角度,可以达到工业智能制造的要求。     

同步发电机绝对转子角测量方法研究

本文介绍了同步发电机绝对转子角的定义,提出了一种测量绝对转子角,进而获得高精度的相对转子角的方法;此方法不使用机端电压过零整形脉冲,而是将机组键相脉冲与GPS定时脉冲比相,并能够自动整定初始位置角,因此,测量结果不受发电机运行状态的影响,能够在各种运行方式和扰动情况下获取高精度的绝对转子角。本文提出的方法已在大量火电厂、水电厂工程中实际应用,效果良好。     

Vertical combdrive based 2-D gimbaled micromirrors with large static rotation by backside island isolation

We introduce a backside island isolation method for silicon-on-insulator (SOI)-based microelectromechanical systems technology and demonstrate vertical comb drive-based two-dimensional gimbaled micromirrors with large static rotation using the isolation method. The proposed isolation method provides electrical isolation and mechanical coupling of SOI structures without additional dielectric backfill and planarization by utilizing timed etched backside handle wafer structures. The backside island is a hidden layer beneath the gimbal and allows independent application of actuation potentials to the gimbal and inner mirror. We developed the fabrication process that accommodates the backside island isolation structures into an established vertical comb drive process, thereby allowing implementation of two-axis gimbaled structures. The maximum static optical deflections of the gimbal and mirror are 46/spl deg/ and 15/spl deg/, respectively.     

Running characteristics of the superconducting magnetically levitated train in the case of superconducting coil quenching

A superconducting (SC) magnetically levitated (Maglev) transportation system has been developed in Japan and various experiments have been done on the new test line in Yamanashi prefecture. Although the superconducting electrodynamic suspension (EDS) system has the advantage of stable levitation without active control, various electromagnetic or mechanical disturbances can change the gap length and cause the displacement or oscillation of the bogie. In this system, the severest disturbance is SC coil quenching. Therefore, it is important to determine the running characteristics of the Maglev train and to increase the stability in this case. We developed a three‐dimensional numerical simulation program for the Maglev train. Using this program, a running simulation of the train for the Yamanashi new test track was undertaken in the case of SC coil quenching. Because of the damping characteristics of the EDS system, the influence of coil quenching is smaller at higher speeds. In the train model, the electromagnetic spring strength of the EDS system is larger than that of the mechanical spring of the secondary suspension system connecting the bogie and cabin. Therefore, influence of the quenching is only seen in the cabins connected to the quenched bogie. Demagnetization of the SC coil quenching is considered to increase the stability of the train. Although this method is useful to decrease large guidance force, lateral displacement, yaw and roll angle of the bogie, vertical displacement, and pitch angle become large. © 1999 Scripta Technica, Electr Eng Jpn, 130(1): 95–105, 2000     

CIE眩光指数（CGI）的应用研究

不舒适眩光是室内照明质量评价的重要指标，国际上有多种对不舒适眩光评价 的方法，其中ＣＩＥ推荐的眩光指数（ＣＧＩ）公式是目前较好的数学表达方法，但 ＣＩＥ推荐的数学模型仅针对灯具的光轴与铅垂电一致（垂直旋转角为零）的情况， 本文进一步提出了在灯具垂直偏转角不为零时的数学模型，并介绍了作者编制的计 算机软件，这对类似体育馆等有较高垂直照度要求场所的眩光评价，具有较大的实 用价值。     

V形复合绝缘子力学特性研究

绝缘子串的风偏闪络一直是影响输电线路安全运行的主要问题之一。针对哈密—郑州±800 kV特高压直流工程的V形复合绝缘子串风偏设计校核问题,在I形绝缘子串弦多边形方法的基础上,构建并推导了适用于V形复合绝缘子串（含金具等）的弦多边形计算方法,并利用有限元方法验证了该方法的准确性和有效性,给出了确定该方法适用范围的最小轴向拉力计算方法。进而基于该特高压线路的参数,应用此方法研究了V串夹角、导线平均高度及水平档距/垂直档距组合变化对风偏特性的影响。结果表明,在给定垂直档距和水平档距条件下,建议V串夹角随导线平均高度增大而增大;在给定导线平均高度和垂直档距条件下,建议V串夹角随水平档距增大而增大;在给定导线平均高度和水平档距条件下,建议V串夹角随垂直档距增大而减小。给出了不同导线平均高度、垂直档距和水平档距条件下所建议的V串夹角值。     

斜掏挖与直掏挖斜插角钢基础性能对比

为了对比斜掏挖基础和直掏挖斜插角钢基础,设计了4个单腿试验基础。从基础位移、地基土压力、钢筋应力分布及经济性方面对比了2种基础。试验表明,相同尺寸的斜掏挖和直掏挖斜插角钢基础,虽然其抗拔承载力大体相同,但基础受力分布不同。斜掏挖基础相比直掏挖斜插角钢基础具有优越性。     

青藏联网工程冻土地基装配式基础载荷试验研究

为评价青藏交直流联网工程冻土地基杆塔基础稳定性,进行了粗粒冻土地基装配式真型基础在竖向上拔与水平荷载或下压与水平荷载共同作用下的载荷试验,试验基础施工采取与工程基础尺寸、施工工艺和时期一致的原则,根据试验结果,分析了基础极限及破坏状态,研究了荷载与位移关系曲线特征及承载特性,求得试验基础的承载能力及“土重法”上拔角等设计参数的取值。试验研究结果表明,试验荷载作用下粗粒冻土装配式基础因水平位移过大而失稳,荷载与位移关系曲线表现为非陡降型,活动层冻结状态时地基强度及基础承载性能优于融化状态,粗粒冻土地基上拔角大于13°,装配式基础承载力满足设计要求。     

一种可穿戴指间角度测量系统设计

针对人机交互的需求提出了一种可穿戴的指间角度测量系统。 首先,基于弹簧片和应变片设计了可穿戴的指间角度传 感器及其便携式测量电路,对指间角度的测量原理和传感器的测量电路进行了详细分析。 其次,基于 LabVIEW 开发了测量系 统的上位机软件,对指间角度传感器的数据进行滤波和角度解算,并采用图片分割旋转的方法实现了指间角度的可视化动态显 示。 最后,为验证系统的有效性进行了实验,结果表明,在 0 ~ 30° 测量范围内,设计的指间角度传感器的非线性误差为 2. 38%FS,迟滞误差为 1. 94%FS,重复性误差为 5. 29%FS,总精度为 6. 11%FS。     

Improved Radial Force Modeling and Rotor Suspension Dynamics Simulation Studies for Double-winding Bearingless Switched Reluctance Motor

The rotor radial force is changed by adjusting the windings current value to control rotor suspension for various kinds of bearingless switched reluctance motor (BSRM). To accomplish the BSRM's suspension control, the radial force analytical model is necessary. Currently the mathematic relationship among radial force, winding currents, and rotor rotation angle has been built for double-winding BSRM, but the rotor eccentricity displacement has not been considered. That is, the existing radial force analytical model only can be used to analyze rotor radial force when rotor shaft is located in the central position. Actually, the rotor radial force is significantly affected by the rotor shaft eccentricity displacement. It is difficult for the bearingless motor to keep the rotor shaft staying in the central position, and the rotor shaft always runs around the central position with an eccentricity displacement. The rotor eccentricity caused by the radial force is considered in the paper to obtain the air-gap permeance and the windings inductances. Furthermore, the radial forces analytical model considering the rotor eccentricity displacement is derived. Finally, the finite-element method (FEM)-based results are applied and the dynamics simulation using the proposed model is accomplished to verify the correctness of the model.     

Three-dimensional SOI-MEMS constructed by buckled bridges and vertical comb drive actuator

A new method for realizing three-dimensional structures based on the standard silicon-on-insulator microelectromechanical systems is developed using vertically buckled bridges as structural elements. The vertical displacement, profile of the bridge, and obtainable accuracy of the displacement are examined. Using the lateral dimension control of the bridge and the supporting beams, the vertical positioning is realized based on the planer photolithography. As a demonstration, a vertical comb drive actuator is prepared and its performance is examined.     

Surface micromachined segmented mirrors for adaptive optics

This paper presents recent results for aberration correction and beam steering experiments using polysilicon surface micromachined piston micromirror arrays. Microfabricated deformable mirrors offer a substantial cost reduction for adaptive optic systems. In addition to the reduced mirror cost, microfabricated mirrors typically require low control voltages (less than 30 V), thus eliminating high-voltage amplifiers. The greatly reduced cost per channel of adaptive optic systems employing microfabricated deformable mirrors promise high-order aberration correction at low cost. Arrays of piston micromirrors with 128 active elements were tested. Mirror elements are on a 203-μm 12×12 square grid (with 16 inactive elements, four in each corner of the array). The overall array size is 2.4 mm square. The arrays were fabricated in a commercially available surface micromachining process. The cost per mirror array in this prototyping process is less than $200. Experimental results are presented for a hybrid correcting element comprised of a lenslet array and piston micromirror array, and for a piston micromirror array only. Also presented is a novel digital deflection micromirror that requires no digital to analog converters, further reducing the cost of adaptive optics systems