锁定放大器在时栅位移传感器动态测量中的应用

时栅位移传感器在进行动态测量时,除激励磁场外,持续运动的圆栅转子/直线栅动子也影响动测头信号的变化,以致时栅的测量精度下降.研究了一种基于锁定放大器的信号处理方法,用于时栅动、定测头信号的处理,仿真实验和实际动态误差采集表明,该处理方法可以解决上述问题.     

一种高精度的曲轴凸轮轴非接触测量方法

为了提高曲轴及凸轮轴测量的精度与效率,提出了一种新型的高精度非接触的测量方法.采用旋转平晶的方法得到扫描红外LED光束对被测件测量,PIN管进行光电转换,精密计时电路则计算出光束经过被测件边缘的时刻,换算出被测尺寸.分析结果表明:入射光束倾斜角、计时电路满足一定的要求时可以达到极高的精度.     

频率量的动态智能测量系统

本文所提供的频率量动态测量系统不但能进行稳态测量,也可进行动态测量。由于配备了单片微型计算机,稳态测量时可以进行数字滤波,故精度较高;动态测量的跟踪能力可达被测频率的一个周期。该系统可用作计算机的一个智能终端,也可单独作为测试仪器或实时控制系统中的一个环节。     

动态振动位移的高速精密测量方法研究

为了克服常规位移测量计数器测量的动态范围窄的缺点，介绍了一种能够精密测量振动位移的方法。该方法采用莫尔条纹技术测量位移，通过高速数据采集和高速信号处理，能够测量机械结构的大幅度、宽动态范围的振动位移。由于振动位移的方向随时改变，测量时对鉴向的要求比较高。本文提出了一种莫尔条纹计数细分方法，可以完成高速鉴向及可逆计数。该方法具有量程大、分辨率高、响应速度快、抗干扰的特点。     

相位式磁栅转矩传感器

本文介绍了一种基于相位转矩测量原理,以磁栅为发讯器的转矩传感器。利用该传感器构成的转矩测量仪可大幅度减少被测传动系统的转速波动对转矩测量的影响,尤其适用于动态转矩的高精度测量。     

金属线材折弯虚拟仿真系统的设计与实现

针对金属线材产品种类多、结构复杂度高、加工过程动作多且易发生碰撞干涉等特点,研究金属线材产品建模和仿真加工技术,实现线材产品的加工仿真,以检查产品设计和机床加工动作的合理性,优化加工工艺。分析了折弯机械的运动控制和折弯工艺,推导出产品建模参数与样机运动参数的数学关系式。基于OpenGL API,使用分段建模的方法实现线材产品参数化三维建模;使用“嵌套矩阵法”和运动控制函数实现线材的加工仿真。虚拟仿真系统由产品建模模块和仿真加工模块组成,前者用于产品建模和三维模型显示,后者用于加工轨迹规划和加工动画演示。实验表明,仿真系统可以实现金属线材产品在线设计和加工工艺优化,能够加快产品设计和试加工过程。     

测量齿轮整体误差时的错齿方法

<正>在CZ450齿轮整体误差测量仪上测量齿轮整体误差,由于采用间齿测量,当遇到被测齿轮齿数能被标准蜗杆头数整除时,整体误差测量工作不能连续自动错齿,测量时被测齿轮转动一周自动停止测量后,必须进行人工错齿后再行启动继续测量,即借助于仪器拖板手轮将被测齿轮移开脱离与标准蜗杆啮合,人工顺着齿轮原转动方向使齿轮转动一个齿,再移动拖板使齿输进入正确啮合位置(由千分表或其他指示器控制中心距)启动仪器进行第二圈测量。当用二头蜗杆测量时,人工错齿一次就可以完成整个测量工作了;当用三头蜗杆测量时,须进行二次人工错齿才能完成整体误差的测量。     

脉冲激光测距中高精度时间间隔测量方法的研究

高精度时间间隔测量对脉冲激光测距系统具有重要意义,为此提出了一种新的高精度时间间隔测量方法。该方法在FPGA中实现了脉冲计数法、多相采样法和延迟链法的结合。采用脉冲计数法对被测时间间隔进行“粗值”测量,保证大的动态测量范围。利用FPGA内部锁相环产生N路同频率,相位均匀分布的时钟信号作为计数时钟,基于等精度测频原理,将被测时间间隔的测时分辨率提高到Tclk/N。利用FlipFlop锁存器形成延时链,对被测信号与相邻计数时钟的时间间隔进一步量化。该方法解决了传统多相采样技术中倍频次数高则相移分辨率降低的问题,在不增加计数时钟和有限延迟链数量的前提下,得到较高测时分辨率。测试结果表明,该时间间隔测量模块不但可以实现大的动态测量范围,而且测时过程相对较短,具有较高测时精度。     

脉冲激光测距中高精度时间间隔的测量

考虑时间间隔测量对脉冲激光测距系统的意义,提出了一种新的高精度时间间隔测量方法.该方法在现场可编程门阵列(FPGA)中实现了脉冲计数法、多相采样法和延迟链法的结合.采用脉冲计数法对被测时间间隔进行"粗值"测量,保证大的动态测量范围.利用FPGA内部锁相环产生N路同频率,相位均匀分布的时钟信号作为计数时钟,基于等精度测频原理,将被测时间间隔的测时分辨率提高到Tclk/N.利用FlipFlop锁存器形成延时链,对被测信号与相邻计数时钟的时间间隔进一步量化.该方法解决了传统多相采样技术中由于倍频次数高导致相移分辨率降低的问题,在不增加计数时钟和有限延迟链数量的前提下,得到较高测时分辨率.测试结果表明,该时间间隔测量模块的动态测量范围为163.8 μs,测时过程相对较短,当进行多次重复测量时,测量的标准误差在71 ps以内,基本满足实际应用的精度要求.     

基于三坐标测量机双参数向自适应测量自由曲面

提出一种基于三坐标测量机的双参数向自适应测量自由曲面方法。CMM手动测量被测曲面边界点后,连接点生成可测区域,由可测区域自动拓扑生成几条均布初始扫描线以及每条扫描线的均匀初始点,对于U向的各条扫描线,CMM在自动测完初始点后,不断拟合已测点为B样条曲线,由曲线末端曲率自适应预测下一测点并指导CMM自动测量。测完初始扫描线后拟合已测点云为B样条曲面,由曲面V向边界最大曲率自适应确定下一扫描线位置,并进行该条扫描线U向自适应测量,重复这一过程直至曲面测量完毕。测点可随被测曲面自身曲率变化特性而疏密分布,曲率变化大的重要特征区域分布密集,曲率变化小的非重要区域分布稀疏,既保证了重要特征点不会遗漏又避免了数据冗余。理论曲线曲面自适应测量实验结果表明该方法测量精度可达微米级,实例零件应用验证了该方法的可行性。     

激光—CCD实时、无接触、动态线径测量的研究

非衍射式激光-CCD线径测量方法,由于没有克服光学镜头非线性畸变引起测量误差的可行办法,至今不能得到实际应用。本文提出的计算机测量误差自动修正方法可以有效地解决这个问题,在此基础上,一种小体积、造价低、直径测量范围宽和高精度的线径测量装置得以研制。它在电线厂漆包线生产线上实现了实时、无接触、动态线径测量。     

双光源投影法细丝直径测量

提出一种细丝直径在线测量方法,利用半导体激光作为点光源,发出球面波;通过细丝后在其后菲涅耳衍射区留下阴影,测量阴影宽度可得细丝直径;同时,利用两个相距一定距离的点光源对同一细丝投影,测量两个投影之间的距离可得细丝位置的晃动量,从而校正直径测量值。     

一种新的瞬时测速方法

提出一种基于８０３１单片机的高速冲击缸活塞运动瞬时测速方法,并对其运动参数的测试问题进行了研究,可以精确测量出高速气缸活塞杆的瞬时速度,并可应用于其它类似的测速问题中。     

激光棒干涉测量中单双通法的对比

由于激光棒具有细长的特殊形貌特征,传统的双通测试方法虽然灵敏度较高,但是往往存在明显的衍射效应和多重成像导致的边缘黑环,这会导致有效测量面积的缩减,对于小口径光学元件的测量尤为不利。为了克服这一缺陷,采用单通法测量激光棒的波前畸变,使用直角棱镜作为反射件,使得测试光仅通过激光棒一次,从而减少光路中的等效圆孔数和成像次数,抑制衍射和边缘重叠。利用展开的多小孔模型讨论了衍射效应的影响,并且从成像角度讨论边缘重叠的成因,从而得出单通法的优势。另外,为使参考光与测试光的匹配,需要将直角棱镜旋转至少5.40°偏摆角以提高干涉条纹的对比度。最终测得激光棒波前畸变的峰谷值为0.068λ,均方根值为0.012λ。     

The measurement of the axial internal stress in steel wire

Apparatus is described for the measurement of the approximate axial internal stress distribution in wires typically 0·3–0·4 mm diameter. A sensitive optical system measures the change of length of the wire as its diameter is reduced at a rate of about 0·3 μm per minute by dissolution in 0·012 M nitric acid maintained at a constant temperature. The change of area of cross section of the wire is deduced from measurement of its electrical resistance. The adoption of a continuous thinning process makes it possible to measure the internal stress at the original wire surface. The method is not able to take account of the effect on the axial strain of the relief of circumferential and radial stresses. This leads to the axial stress being underestimated by about 30%. Internal stress measurements are reported on patented and drawn steel wire which confirm the wide range of internal stress intensity that can be generated in this material by changing and drawing conditions.     

Force Analysis and Curve Design for Laying Pipe in Loop Laying Head of Wire Rod Mills

Laying head is a high-precision engineering device in hot-rolled high speed wire rod production line. Previously research works are focused on the laying pipe wear-resisting. Laying pipe curve design method based on wire rod kinematics and dynamics analyses are not reported before. In order to design and manufacture the laying pipe, the motion and force process of the wire rod in the laying pipe should be studied. In this paper, a novel approach is proposed to investigate the force modeling for hot-rolled wire rod in laying pipe. An idea of limited element method is used to analysis and calculates the forces between laying pipe inner surface and wire rod. The design requirements of laying pipe curve for manufacturing are discussed. The kinematics and dynamics modeling for numerical calculation are built. A laying pipe curve equation is proposed by discussing design boundary conditions. Numerical results with di erent laying pipe curves design parameters are plotted and compared. The proposed approach performs good result which can be applied for laying pipe curve design and analysis for engineering application.     

大直径轴盘类工件直径测量的研究

大直径轴盘类工件直径的测量具有误差大、动力设备占用时间长、不宜用在生产现场测量等缺点。所以研制一种测量精度能够满足工艺要求,结构简单、价格低廉、适用于生产现场,能够实现在线测量的大直径轴盘类工件直径测量装置确属当务之急。常用的大直径轴盘类工件直径测量弓高弦长法虽测量精度高、重复性好,但必须在工件处于静止状态下才能进行测量,不能实现在线测量。如果把工件的直径通过步进电动机驱动齿条转换为光栅的长度,通过光栅长度的测量即可实现大直径轴盘类工件直径在线测量,并大幅提高测量精度。     

Wear mechanism of metal bond diamond wheels trued by wire electrical discharge machining

The stereographic scanning electron microscopy (SEM) imaging was used to investigate the wear mechanism in wire electrical discharge machining (EDM) truing of metal bond diamond wheels for ceramic grinding. A piece of the grinding wheel was removed after truing and grinding to enable the examination of wheel surface and measurement of diamond protrusion heights using a SEM and stereographic imaging software. The stereographic SEM imaging method was calibrated by comparing with the profilometer measurement results. On the wheel surface after wire EDM truing and before grinding, some diamond grain protruding heights were measured in the 32 μm level. Comparing to the 54 μm average size of the diamond grain, this indicated that over half of the diamond was exposed. During the wire EDM process, electrical sparks occur between the metal bond and EDM wire, which leaves the diamond protruded in the gap between the wire electrode and wheel. These protruding diamond grains with weak bond to the wheel were fractured under a light grinding condition. After heavy grinding, the diamond protrusion heights were estimated in the 5–15 μm range above the wear flat. A cavity created by grinding debris erosion wear of the wheel bond could be identified around the diamond grain.     

Wear of die after drawing of pickled or reverse bent wire rod

The object of this paper was to evaluate the difference of die wear by using wire rods descaled by two different treatments; pickling or reversed bending. The paper gives a background of wear mechanism and describe a method to estimate die wear in wire drawing. The conclusions of the experiments were that the wire rod preparation seems to be of minor importance for the wear of die. A die in the sixth draft had a magnitude lower wear, compared to the die in the first draft. Abrasive wear is present from the WC grains, torn out in the adhesive wear, on both dies used on pickled wire rod and reverse bent and steel wool cleaned wire rod.     

啮合线齿廓偏差测量方法

介绍了一种应用于齿轮测量中心上复杂齿廓测量的新方法——啮合线齿廓测量法。该方法减小了测头在X轴方向上运动距离,有效地保证了精度范围,同时减小测头重力中心的运动及测量时间,实现了高精度测量。该方法能够有效防止齿廓基圆测量法在进行内齿轮测量时的干涉现象,同时实现小直径内齿轮(外圆直径小于10mm)的一次装卡完成齿形、齿向和齿距误差测量。