A differential interferometric heterodyne encoder with 30 picometer periodic nonlinearity and sub-nanometer stability

A differential interferometric heterodyne encoder with spatially separated input beams was developed to minimize periodic nonlinearities resulting from polarization mixing. The laser beams with different frequencies were delivered by two polarization-maintaining fibers to the encoder head. Under laboratory conditions this encoder demonstrated a system stability of 38 pm (standard deviation) and 100 pm over 30 s and 1 h respectively. In a comparison measurement with a differential heterodyne interferometer, this encoder showed periodic nonlinearities of less than 30pm without any additional correction.     

一种利用相序测定原理的编码器计数方法

介绍了一种已获取发明专利的相序测定计数方法,以Atmel89S52单片机为基础,通过编码器的输出脉冲A和其反向脉冲A-产生中断,在中断服务程序中读取脉冲A、A-及与A脉冲相位差为90°的脉冲B的电平并与已在E2PROM中储存的状态字进行比较,由此来确定旋转方向并对脉冲进行加减计数。同时,该文也介绍了相应的硬件电路和软件程序。该方法在实际应用中的测试表明,当编码器频繁改变旋转方向时仍具有很高的测量准确度并能有效地抑制脉冲干扰信号。     

单圈绝对式电子经纬仪测角信号处理

为实现快速、高精度角位移测量,提出了一种单圈绝对式电子经纬仪测角信号处理算法。只需刻画脉冲左右边沿在阈值附近各2个采样点就可以快速估计出脉冲宽度和脉冲中心坐标;对现有文献细分方法进行改进,给出了基于多组刻画脉冲中心求解高分辨力细分角的公式;并对算法时间复杂度和抗噪声性能分别进行了分析与仿真。实验结果表明,本方法在水平方向上测角误差标准差仅为2.5″,平均每秒钟可测角输出25次,具有实现简单、只需较少计算量就可以获得较高测量精度的优点。研究结果可以为单圈绝对式电子经纬仪、全站仪提供一种新的测角信号处理实用方法。     

脉冲编码器、测速发电机性能自动测试分析系统

脉冲编码器、测速发电机是传动系统中常用的速度传感器,其性能分坏直接影响控制系统的品质指标。本文设计实现了一种基于微机脉冲编码器,测速发电机性能自动测试系统,对该系统的硬件构成和软件分析功能进行了详细讨论。     

光电轴角编码器发展现状分析及展望

系统地介绍了光电轴角编码器的概况、原理和性能以及相应开发工作的新动向。重点对德国的Heidenhain公司、日本和中国的主要生产厂家的产品进行了统计和分析,并就一些新技术、新趋势及母板制造方面进行了展望和评述。     

A method for the evaluation and magnified representation of two-dimensional contouring error

The method of evaluating two-dimensional contouring error between the reference trajectory and the trajectory measured with a cross-grid encoder and magnifying the error is widely used. However, this method has a problem in that the inner cornering error is discontinuously magnified and represented and thus is not accurately detected. Several methods have been proposed to solve this problem, but they have limitations, such as the requirement that an offset value be set or the imposition of conditions on the reference trajectory. Therefore, by calculating errors in the inward direction from a longer trajectory to a shorter trajectory, this paper proposes a new method to continuously magnify and represent the inner cornering error including the corner vertex without the need to set an offset or the imposition of conditions on the reference trajectory. The proposed method was applied to the measurement results at an actual machining center. Consequently, the inner cornering error was continuously magnified and represented, and the error at a corner was accurately calculated using the proposed method.     

Comparison of angle standards with the aid of a high-resolution angle encoder

Germany's National Metrology Institute the Physikalisch-Technische Bundesanstalt (PTB) and the DR. JOHANNES HEIDENHAIN GmbH (HEIDENHAIN) have conducted and compared measurements using their primary angle standards, which are realized as angle comparators of similar design. A high-resolution digital angle encoder served as the transfer standard for this comparison. Calibrations of the transfer standard by the two angle comparators resulted in an agreement of ±0.002″. The result proved to be consistent with the measurement uncertainties that the participants attributed to their calibration. PTB succeeded, using an additional comparison with a self-calibration method, in improving the measurement uncertainty of its comparator by a factor of 2.5 to 0.002″ (k = 2). The results of both participants demonstrated the suitability of the digital angle encoder as transfer standard for angle measurement comparisons aimed at uncertainties of a few thousandths of an arcsecond.     

Design and construction of a two-degree-of-freedom linear encoder for nanometric measurement of stage position and straightness

This paper presents a two-degree-of-freedom (two-DOF) linear encoder which can measure the position along the moving axis (X-axis) and the straightness along the axis vertical to the moving axis (Z-axis) of a precision linear stage simultaneously. The two-DOF linear encoder is composed of a reflective-type scale grating and an optical sensor head. A reference grating, which is identical to the scale grating except the scale length, is employed in the optical sensor head. Positive and negative first-order diffracted beams from the two gratings are superposed with each other in the optical sensor head to generate interference signals. The optical configuration is arranged in such a way that the direction of displacement in each axis can also be detected. A prototype two-DOF linear encoder is designed and constructed. The size of the optical sensor head is about 50 mm (X) × 50 mm (Y) × 30 mm (Z) and the pitch of the grating is 1.6 μm. It has been confirmed that the prototype two-DOF linear encoder has sub-nanometer resolutions in both the X- and Z-axes.     

Improving the performance of incremental encoders with conditioning circuits based on FPGA

This work presents a conditioning circuit to improve the performance of incremental encoders that allows multiplying the number of counts by four with a high speed response. This circuit is described in VHDL and is synthesized for an FPGA so it can be included in an embedded system. Practical results of the solution, both from simulation and actual data, are presented.     

高精度重力仪的测量原理与发展现状

重力仪拥有广阔的应用空间,是获取重力相关信息所使用的最直接和最重要的仪器之一,对涉及重力测量的行业起着无可替代的支撑作用。重力测量原理的完善与创新能够极大地提高相关重力测量仪器的测量能力。首先介绍了重力仪的基本概念与分类,然后根据重力测量原理的成熟程度和相关重力仪应用的广泛程度,选取了自由落体重力仪、原子干涉重力仪、弹簧重力仪和超导重力仪4种目前重力仪行业内最为典型的重力仪,分别介绍了它们的测量原理与发展现状,并重点总结了与重力仪测量精度有关的指标,最后对国内外重力仪的相关研究情况进行了总结和展望。     

Assessment of non-rigid body,direction- andvelocity-dependent error motions and their cross-talk by two-dimensional digital scale measurements at multiple positions

The conventional volumetric error compensation for a machine tool is based on the machine's kinematic model, which formulates the tool center point (TCP) position based on the assumption of rigid-body motion of each axis. Particularly in large-sized machine tools, error motions that do not satisfy this assumption may have a significant impact on the machine's overall volumetric accuracy. In addition to position-dependent quasi-static error motions included in the conventional kinematic model, this paper proposes a scheme to assess quasi-static cross-talk between axes and direction- and velocity-dependent error motions. This paper proposes test procedures to measure two dimensional (2D) contour error trajectories by using a 2D digital scale (cross grid encoder). Unlike many previous works, this paper proposes to perform the tests at multiple positions over the machine tool's entire workspace, and the error motions are assessed by comparing contour error profiles. An experimental case study on a large-sized bridge-type vertical machine tool shows that such influences can be significant error contributors. The proposed tests can assess error motions only at discrete points where a 2D digital scale is installed. It can be applied as accuracy inspection to ‘‘roughly’’ assess the machine's volumetric accuracy by using a 2D digital scale only, but it is generally not for the compensation.     

位标器框架平台用单磁极磁电编码器设计

角位移传感器对于伺服控制闭环是一个重要的反馈元件,在军工和航天领域,旋转变压器和光电编码器本身的缺陷限制了其应用.为了弥补传统角位移传感器的不足,选择磁电编码器作为位标器框架平台的角位置反馈器件.依据校准查表信号细分算法研制出了一种单磁极磁电编码器,并设计了温漂补偿算法,以扩大工作温度适用范围,并为之设计制作了配套使用的校准和检测系统.经过实验验证,所研制的磁电编码器满足了位标器的应用要求.     

异轴间接角度测量系统设计与研制

介绍了一种异轴间接角测量系统。系统中用一旋转编码器与被测轴按任意啮合比进行啮合,在被测轴上贴一零度光标,并用光电传感器把零度光标转变为电脉冲信号。系统先依据零度脉冲记录被测轴正转一周旋转编码器输出的脉冲数,再用单片机依据这一数据和旋转编码器输出的当前脉冲数,计算和显示被测轴当前角度。实验证明这一系统的测量误差小于0．5℃。此系统具有安装简单和调整方便的优点,被成功有于动平衡验机上。     

轿车后排路噪问题分析与改进

为了解决匀速后排路噪超标问题,对底盘悬架车身接附点振动进行了调查,测试结果表明后减振器与车身接附点z向对应后排路噪峰值频率处振动偏大.为了有针对性地优化减振器阻尼力降低减振器上安装点对车身的振动激励,自主设计了后减振器工作速度测试方法.利用测试数据提取得到的减振器速度特性曲线,优化该工作速率段减振器阻尼力并进行了实车验...     

基于单片机和编码器的风轮机测速装置设计

设计了一种用于风轮机测速和物料计数的测量装置。该测量装置采用增量式光电编码器对叶轮的角位移进行测量,运用M法进行转速计算,采用单片机实现测量数据的采集与处理,采用八位七段数码管实时显示叶轮转速和物料数量。实践证明,该装置具有简单易行,测量准确,使用方便和成本低廉的特点。     

一种新型高性能价格比数控系统

介绍了当前工业发达国家数控技术的研究方向和我国数控技术发展的现状,提出了一种新型高性能价格比的数控系统,并介绍了该系统的原理与结构,为国内研究数控技术提出了一条新途径。     

Research on the parallel load sharing principle of a novel self-decoupled piezoelectric six-dimensional force sensor

This paper presents a novel integrated piezoelectric six-dimensional force sensor which can realize dynamic measurement of multi-dimensional space load. Firstly, the composition of the sensor, the spatial layout of force-sensitive components, and measurement principle are analyzed and designed. There is no interference of piezoelectric six-dimensional force sensor in theoretical analysis. Based on the principle of actual work and deformation compatibility coherence, this paper deduces the parallel load sharing principle of the piezoelectric six-dimensional force sensor. The main effect factors which affect the load sharing ratio are obtained. The finite element model of the piezoelectric six-dimensional force sensor is established. In order to verify the load sharing principle of the sensor, a load sharing test device of piezoelectric force sensor is designed and fabricated. The load sharing experimental platform is set up. The experimental results are in accordance with the theoretical analysis and simulation results. The experiments show that the multi-dimensional and heavy force measurement can be realized by the parallel arrangement of the load sharing ring and the force sensitive element in the novel integrated piezoelectric six-dimensional force sensor. The ideal load sharing effect of the sensor can be achieved by appropriate size parameters. This paper has an important guide for the design of the force measuring device according to the load sharing mode.     

基于平面驻波磁场的二维位移传感器 测量原理与结构优化

在芯片制造、智能制造、航空航天等领域,精密平面定位迫切需要平面两维度位移的同步独立精密测量。本文提出一种基于电磁感应原理的平面位移传感器,由动阵面和定阵面组成。定阵面由m×n个平面螺旋线圈阵列串联而成,通入交变励磁电信号时在测量平面产生平面驻波磁场。动阵面由四个螺旋线圈以2×2矩阵形式排列,感应出振幅随x轴和y轴位移变化的四路调制信号,并利用Cordic算法求解两维度位移量。本文首先介绍了传感器的工作原理,对电磁模型进行有限元分析,并对位移解算算法进行数值模拟。根据仿真结果对测量误差进行分析溯源,优化传感器结构。制作传感器样机开展了实验验证,验证了传感器结构和位移解耦方法的可行性。实验表明,传感器在节距内最大误差为48.7μm,分辨率为0.317μm,在147 mm×147 mm量程范围内,传感器线性度达到0.15%,为高精度电磁感应式平面二维位移传感器的进一步发展提供了理论支撑和实验指导。     

一种新型高灵敏度三维成像系统电路设计

随着激光雷达成像探测技术的发展,人们对微弱信号的探测及目标三维成像需求越来越迫切。为满足在微弱光条件下目标三维成像的需求,本文提出了一种基于SPMArray4阵列光电探测器的新型高灵敏度三维成像探测系统,设计了目标微弱回波信号读出电路,并重点对系统接收电路测距模块作了设计,有效增加了测距精度,为后续信号处理和三维成像提供了条件。     

Development of a novel two-dimensional(2D) three-way(3W) fuel flow control servo valve with constant pressure difference

To solve the problems of large volume, and low integration of traditional electro-hydraulic servo valve with constant pressure differential fuel metering device, a new two-dimensional three-way constant pressure differential fuel flow control servo valve (2D3WFFCSV) is developed. It innovatively adopts the advantages of lightweight of “two-dimensional hydraulic technology”, The constant differential pressure function and flow regulation function are integrated into a two-dimensional (2D) main spool with two degrees of freedom (rotational and axial degrees of freedom). The flow control process of 2D3WFFCSV is as follows: firstly, the armature of the torque motor and the two-dimensional piston are coaxially installed at the end of the two-dimensional piston, so the torque motor can directly drive the two-dimensional piston to rotate; secondly the “hydraulic servo screw mechanism”, which can amplify the power, is used to drive the two-dimensional piston to move in line; Finally, a pair of conversion mechanisms (roller group and spiral track conversion mechanism) are converted into the angular displacement of 2D main spool to control the area of flow valve port. The axial degree of freedom of 2D main spool realizes the function of constant differential pressure. To improve the flow control accuracy of the servo valve, the axial position of the 2D piston is detected by the linear displacement sensor (LVDT), and the signal is transmitted to the controller to realize the closed-loop control. To explore its open-loop characteristics, the mathematical models of torque motor, two-dimensional piston and main spool are established to obtain its open-loop transfer function. Then the AMESIM simulation model is built. To optimize the design of the system, through the dynamic simulation of the system, the influence of key parameters on the dynamic response of the system can be studied. An experimental study is carried out to verify the design feasibility of the servo valve. The experimental results show that under the condition of no-load and full-scale input, the closed-loop delay of the servo valve is 1.84%, the linearity is 2.14%, the step response time is 43 ms, and the dynamic frequency response is 38 Hz. The newly developed 2D3WFFCSV has the advantages of high integration, small size, light weight (801.5 g) and high response and control accuracy. It can replace the constant differential pressure, metering valve and hydraulic servo valve in the aeroengine fuel regulator.