基于温度积分方法的大型数控机床光栅定位热误差建模及实时补偿

为了提高大型数控机床的光栅定位精度,提出了基于热特性分析的光栅定位热误差建模理论及补偿方法.阐述了光栅受热膨胀产生热伸长从而导致定位偏差的机理,并对光栅定位误差产生的影响及表现形式进行了说明.建立了光栅热伸长量和温升量的线性关系表达式.在光栅尺上均匀布置多个温度传感器,实时采集光栅尺多点温度,通过插值运算,拟合出光栅尺各点的温度值.由于在机床运动过程中,光栅尺各点的温升量不尽相同,采用对光栅尺各点温升量积分的方法,求出光栅各点热伸长量,建立了光栅定位热误差模型.利用自主研发的数控机床误差补偿系统,应用光栅定位热误差模型,对落地镗床TK6920进行光栅尺定位热误差补偿.结果显示:光栅定位热误差模型对运动过程中的光栅定位误差进行准确的预测,补偿后残差控制在15μm以内,定位精度提升90%以上,显著提高了光栅的定位精度.

高分辨率光栅精密定位系统研究

为了使光谱分析仪(Optical Spectrum Analyzer,OSA)能精确测量窄谱宽光信号,要求光栅转动一圈分辨200万个点。设计了一种基于衍射光栅、直流无刷电机(Brushless Direct Current Motor,BLDCM)和光电编码器的高分辨率光栅定位系统。实现了基于比例-积分-微分(Proportion Integration Differentiation,PID)的高精度闭环调速控制技术,以驱动BLDCM带动光栅的转动。同时,高精度光电编码器快速检测并反馈光栅的角位置,细分电路对编码器的输出信号作进一步细分。将输出信号的分辨率从16000点/圈提升至2048000点/圈,极大地提升了光栅定位系统的整体分辨率。通过实验测试了光栅扫描速度、波长重复性和波长准确度等性能指标,验证了光栅定位的精度和分辨率。

一种芯棒在润滑链上定位方法的分析

烟宝PQF轧机系统上使用的轧制芯棒，在参与一次钢管轧制后，被送回芯棒循环区域，对芯棒进行冷却、润滑然后送回，参与下一次轧制。本文重点介绍芯棒在润滑完成后如何通过传送链反转定位，保证芯棒准确传送入预穿区域，满足生产节奏对设备的要求。

精密工作台的设计与实验研究

微器件装配技术是实现组合结构的微机械电子学系统(MEMS)的关键技术之一,精密工作台系统则是微装配系统的一个重要组成部分。精密工作台系统包括粗动工作台和微动工作台:粗动工作台包括精密机械及其传动系统、光栅定位系统、直流力矩电机驱动系统及计算机控制系统;微动工作台包括微动台、压电陶瓷驱动电源和电感测微移。实验结果表明,粗动台系统的最高速度为5mm/s,最低速度为3.4μm/s,系统的重复定位精度为±1μm;微动台系统的定位精度可达到±1μm。

测斜仪校准装置控制系统的设计和研发

针对测斜仪的结构原理和工作精度要求,设计和开发了一套测斜仪校准装置的自动控制系统。本装置采用电机驱动、圆光栅定位的机构模式,软件设计采用面向对象的程序设计语言C实现了整个系统的多项功能。

FBG-based ultrasonic wave detection and acoustic emission linear location system

The ultrasonic (US) wave detection and an acoustic emission (AE) linear location system are proposed, which employ fiber Bragg gratings (FBGs) as US wave sensors. In the theoretical analysis, the FBG sensor response to longitudinal US wave is investigated. The result indicates that the FBG wavelength can be modulated as static case when the grating length is much shorter than US wavelength. The experimental results of standard sinusoidal and spindle wave test agree well with the generated signal. Further research using two FBGs for realizing linear location is also achieved. The maximum linear location error is obtained as less than 5 mm. FBG-based US wave sensor and AE linear location provide useful tools for specific requirements.

Aluminum Alloy Material Structure Impact Localization by Using FBG Sensors

The aluminum alloy structure impact localization system by using fiber Bragg grating （FBG） sensors and impact localization algorithm was investigated. A four-FBG sensing network was established. And the power intensity demodulation method was initialized employing the narrow-band tunable laser. The wavelet transform was used to weaken the impact signal noise. And the impact signal time difference was extracted to build the time difference localization algorithm. At last, a fiber Bragg grating impact localization system was established and experimentally verified. The experimental results showed that in the aluminum alloy plate with the 500mm＊500mm＊2mm test area, the maximum and average impact abscissa localization errors were 11 mm and 6.25mm, and the maximum and average impact ordinate localization errors were 9 mm and 4.25 mm, respectively. The fiber Bragg grating sensors and demodulation system are feasible to realize the aviation aluminum alloy material structure impact localization. The research results provide a reliable method for the aluminum alloy material structure impact localization.

An FBG acoustic emission source locating system based on PHAT and GA

Using the acoustic emission locating technology to monitor the health of the structure is important for ensuring the continuous and healthy operation of the complex engineering structures and large mechanical equipment. In this paper, four fiber Bragg grating(FBG) sensors are used to establish the sensor array to locate the acoustic emission source. Firstly, the nonlinear locating equations are established based on the principle of acoustic emission, and the solution of these equations is transformed into an optimization problem. Secondly, time difference extraction algorithm based on the phase transform(PHAT) weighted generalized cross correlation provides the necessary conditions for the accurate localization. Finally, the genetic algorithm(GA) is used to solve the optimization model. In this paper, twenty points are tested in the marble plate surface, and the results show that the absolute locating error is within the range of 10 mm, which proves the accuracy of this locating method.