Three DOF parallel link mechanism utilizing smooth impact drive mechanism

For a wide range of purposes, a compact and smart positioning stage is in strong demand. Our final goal is to fabricate a positioning mechanism that possesses multi-degrees of freedom, a wide movable area, dexterity, rigidity, and high speed. To meet most of requirements, i.e., except that of a wide movable area, a parallel mechanism is superior to a serial link mechanism. However, a lack of smart actuators has previously resulted in a large and complicated construction of a parallel mechanism.A purpose of this paper is to propose a new parallel link that utilizes a smart actuator called smooth impact drive mechanism (SIDM), and to verify its advantage for a smart and compact positioning stage. The SIDM actuator is an interesting mechanism that achieves a long stroke with fine positioning resolution. This paper treats a three DOF stage containing three SIDM actuators and a two-dimensional positioning sensor. The first operation test was carried out, and it was confirmed that a position control was successful. The average deviation was 18.6 μm and the standard deviation was 9.31 μm. As another trial, a circle 3.0 mm in diameter was successfully drawn. These values were insufficient for the SIDM actuator that has potentially nanometer-level resolution. The rough positioning resolution seems to be due to inferior driving method and mechanical ricketiness of the joints. In the near future, high speed and accurate positioning control could be realized with overcoming these problems.     

基于AVR单片机的双液体变焦透镜驱动系统

基于电湿效应的圆锥形双液体变焦透镜是一种新型的透镜,它通过外加电压改变液面曲率半径来实现变焦,从而达到无机械运动变焦的目的。现设计了一种基于AVR单片机的驱动系统,该系统通过调整输出PWM波的占空比可以对外输出一个频率固定为1kHz、幅值可调的电压,用于驱动双液体透镜改变焦距。电控系统可以方便快捷地调整输出电压的大小,从而驱动双液体变焦透镜快速、稳定地改变焦距。     

变焦系统中可调光焦度器件初值分析

为了实现变焦系统中可调光焦度器件初值分析,对可调光焦度器件的变焦系统进行了像差分析。根据变焦系统的光束孔径角和成像物高等特征参数确定系统初级像差,并以像差独立性的原理分析共轴可调光焦度器件变焦系统。采用薄透镜像差理论分析形状参数与变焦系统放大率的关系,应用球差和彗差最小值对可调光焦度变焦系统初值进行确定。结果表明,采用变焦系统放大率与形状参数的计算方法可满足变焦系统中可调光焦度器件初值的确定要求,并具有简单、快速、可靠等特点,为进一步计算机校正变焦系统像差提供了参考。     

齿形链传动啮合冲击机理

在齿形链传动中,链条承受周期性的交变载荷,其中链节啮入轮齿时产生的冲击栽荷影响较大。通过研究标准链条分别与直齿链轮和渐开线齿链轮啮合的啮合冲击,分析发现在链轮上采用渐开线齿能减小链条与链轮啮合瞬间的法向冲击速度,进而降低链条与链轮的啮入冲击。     

惯性冲击驱动管内移动机器人设计

设计了一种以压电双层膜为基本结构,通过惯性冲击原理达到运动驱动目的的管内移动机器人.该机器人主要由一个典型的压电双层膜结构和惯性质量串联构成.工作时,压电双层膜的变形由惯性冲击转化为整体结构的直线位移.从理论上分析了惯性冲击原理的核心问题:惯性冲击力与管壁和机器人之间摩擦力的关系,并通过MATLAB和AN-SYS等软件对整个系统的动态响应做了仿真.相关的验证表明,所设计的管内移动机器人运动步长可以达到0.15μm,具有精密运动和高效率的优点,可以在工业中广泛应用.     

A novel evaluation and compensation method for ultra-precision machining of hybrid lens

In this study, a diffractive-refractive hybrid objective lens (DHOL) compatible with multi-type optical discs (Blu-ray Disc (BD), China Blue High-Definition Disc (CBHD), DVD and CD) was designed and fabricated. The surface of the DHOL was an aspherical (refractive) substrate superimposed on a diffractive sub-structure, and by using ultra-precision single point diamond turning, the form error was reduced to be less than λ/4. However, because of the finite dimensions of the tool radius (R), the pitch of the diffractive structure must be larger than R. This limits the performance of the DHOL and has a bigger effect on the diffractive performance than on the refractive performance. To counteract the limitation, a novel refractive compensation method is proposed. Through superimposing a small refractive curvature, a significant improvement in the diffractive performance was achieved. By reconstructing the wavefront aberration using Zernike expansion and taking the horizontal rotation angle, tool radius and usable cutting edge into account, an optimal design was determined. The optimal design was fabricated and found to perform satisfactorily.     

当量轮系法分析含有差动轮系的传动系统传动比

复杂行星轮系是由简单的轮系按一定的方式组合而成,计算其传动比时,需要列出方程组进行求解,方法较为繁琐,而且对轮系传动的分析也较为复杂,不容易理解。当量轮系方法从分解传动的思路出发,将含有差动轮系的传动系统分解成两个当量分路传动,每个当量分路又可以看成是由若干个简单行星轮系或定轴轮系串联而成,便于传动比的计算和传动分析。最后通过一定的合成方法将两个当量分路传动比进行合成,从而得到整个系统的传动比。该方法分析复杂行星轮系传动,思路清晰,易于理解。     

A suspension integrated with a piezoelectric microactuator for dual stage actuation

This paper presents a shear-mode piezoelectric microactuator that can be easily integrated with a suspension for dual stage actuation used in hard disk drives. The finite element method was employed to investigate the static and dynamic performance of the assembly using a simple cantilever suspension integrated with the microactuator. Experiments were also conducted to verify the numerical analysis results. A modern suspension integrated with the microactuator was then simulated based on the optimised structure of the actuator/suspension assembly, and the results showed that 1.17-μm tip stroke could be obtained while the driving voltage was only 20 V.     

Fast drive of displacement magnification mechanism with flexure hinge using loading type impact damper

A displacement magnification mechanism which uses flexure motion guide using elastic hinges can realize smooth frictionless motion but has poor vibration damping capability. An impact damper is a damping mechanism which uses collision energy to dissipate vibration energy. If the damper is used for vibration control of the flexure mechanism, it may be able to dissipate unexpected vibration without killing the merits of the flexure mechanism. In the paper, a loading type impact damper is applied to settle down transient vibration of a displacement magnification mechanism. We investigate differences of damping effect by setting conditions of the damper. It is shown that the impact damper can eliminate residual vibration at step response effectively without steady state error. The experimental displacement magnification mechanism with impact damper can settle down less than 1/5 of the response without the damper under appropriate setting conditions. Influence of natural frequency ratio between damper and displacement magnification mechanism is investigated. Influences of indentation at impact point are also examined.     

A friction drive system for accurate positioning

A transmission system for positioning a conventional moving table has been constructed. The gearbox which has been inserted between the lead screw and the driving stepping motor is of the friction type. The resolution of the system has been measured to be less than 0.01 μm     

一种新型的无菌砖包机双滑块并联横封机构的设计与分析

设计了一种基于伺服驱动的无菌砖包双滑块并联横封机构,这种横封机构把伺服驱动控制技术与并联五杆机构结合在一起,可以实现高精度的运动输出,满足包装工艺所要求的复杂运动规律,并且通过编程可以方便地实现设备的柔性化。使用ADAMS机构仿真程序进行了运动学和动力学模拟分析,得到横封机构的运动学及动力学特性曲线。分析表明:所设计横封机构实现了预定的工艺动作,满足要求;仿真得到了各主驱动驱动力的变化曲线,表明横封机构在张开和闭合动作过程中存在比较明显的柔性冲击;两个主驱动的瞬时功率曲线为伺服电机选取提供了依据。     

大面阵中波红外连续变焦光学系统设计

针对制冷式大面阵640×512凝视焦平面阵列探测器,设计了一套中波红外连续变焦光学系统。该系统由变焦系统和二次成像系统构成,包括7片透镜和2个反射镜组成的折叠光路。首先,根据变焦原理和专业光学设计软件给出了系统结构及其参数。然后,分析了系统的像质和冷反射效应。最后,验证了系统的性能指标。结果表明:该系统可以实现50～500mm的连续变焦,变焦过程中目标景物始终清晰可见;系统在耐奎斯特频率处的全视场光学传递函数大于0.35,全视场畸变小于2%,无冷反射现象;具有分辨率高、热灵敏度高、像质好、变焦轨迹平滑等特点,基本满足设计要求。     

控制棒驱动机构钩爪齿复合冲击磨损可靠性分析

文中基于改进后的Lewis复合冲击磨损模型,利用蒙特卡洛仿真方法获得在不同步跃运动步数下的控制棒驱动机构钩爪齿磨损量分布,进而应用广义应力-强度干涉理论和有限差分法分别进行了钩爪复合冲击磨损的可靠性分析与灵敏度分析.采用某型号控制棒驱动机构的相关数据进行案例分析后,发现现有的钩爪能够满足600万步的步跃运动的设计寿命要...     

电驱动换挡机构疲劳寿命试验系统设计

根据电驱动换挡机构疲劳寿命试验要求,设计开发了基于电驱动换挡机构疲劳寿命为评价指标的试验系统;并就系统的组成、工作原理和测控软件等进行了详细介绍。经试验验证,该系统稳定可靠,操作方便,很好地满足了电驱动换挡机构疲劳寿命试验的要求。目前,该系统已在多款电驱动换挡机构研发阶段取得了良好的应用效果。     

Control system for a machine-tool drive with compensation of spindle eccentricity

A method is developed for compensating spindle eccentricity and thereby improving machining precision, by feedback-based correction of the transverse supply.     

小型高灵敏度水下拉曼光谱系统

为了使水下拉曼光谱系统更加易于搭载和布放,并进一步提高其探测能力,研制了一套探头式的小型高灵敏度水下拉曼光谱系统并对其探测能力进行了评估。通过优化结构设计和严格的器件选型,系统的体积和重量得到了有效的控制,其主体舱尺寸为Φ260mm×L795mm,重量为548N,仅为国际上报道的首台深海拉曼光谱系统(DORISS)质量的三分之一。将激光器从主体舱移至探头舱,有效避免了传统光学探头中激发光耦合进入光纤时产生的耦合损失以及激光在传输过程中引起的杂散光干扰。系统采用了300mW能量可调激光器配合高衍射效率的体相位全息光栅和半导体制冷CCD,有效提高了探测灵敏度。实验结果表明,系统对于硫酸根的检测限在0.4mmol·L-1以下,是DORISS探测能力的4倍,同时能够实现对水下矿石种类的原位鉴定。该深海拉曼光谱系统在海洋原位探测方面展现出了良好的应用前景。