精密微小型制造理论、技术及其应用

以中间尺度的微小型构件为目标,以传统制造技术为基础,提出精密微小型制造技术概念和主要内涵.提出并实现了高转速数控精密微小型车铣复合加工技术,研究在微小型车铣复合加工中心上进行微小型零件完整性加工的工艺技术及特性.针对超薄、异型微小型金属构件的制造,提出大功率高频群脉冲电化学微小型制造方法和工艺.提出并初步研究基于制造特征仿真的相关理论和建模方法,介绍应用实例.提出基于工艺匹配原则的计算机显微检测技术,介绍关键技术研究进展.     

分形理论及小波分析在快速故障诊断中的应用研究

本文提出了一种小型故障诊断系统的数据处理模式,叙述了分形理论在系统中的应用,论述了小波分析在突变信号分析中的应用和本系统中的算法,在算法研究的基础上进行了实验信号分析,验证了上述数据处理方式的可行性。     

三种常见典型柔性铰链的非线性分析

以三种常见的柔性铰链作为研究对象,对柔性铰链进行非线性分析.因为铰链需要线性变形,因此利用有限元分析软件ANSYS对柔性铰链进行系统的研究,讨论铰链的各个参数对其线性性能的影响.同时因为柔性铰链采用金属材料,只能产生小变形,作用力过大时会发生屈服,因此分析了柔性铰链在所能承受的最大作用力下的结构非线性,计算了铰链的线性工作范围,为柔性铰链在机构中的应用提供了一定的基础.     

高频群脉冲电化学微小型加工中的反向电流与压力波

针对脉冲电化学加工，建立了反向电流和压力波的数学模型，提出了高频群脉冲电化学加工方法。结果表明，充分发挥反向电流作用的电源频率在10～24kHz之间，压力波频率在400～1333Hz之间。反向电流仅与电极本身有关，它决定了高频群脉冲电化学加工的主脉冲频率；压力波则除了电极外，还与电解质性质和流速、极间间隙和电压等有关，它决定了高频群脉冲电化学加工的调制脉冲频率。根据模拟结果设计的实验表明，良好的加工质量来源于高频群脉冲带来的较小极间间隙。     

考虑关键运动副特点的船用多功能数控机床模态分析

针对船用多功能数控机床在舰船环境下的结构动态性能研究,结合舰船波浪载荷作用下的摇荡特点,揭示了机床的运动坐标体系和布局方案,并进行了机床关键导轨滑块运动副5自由度载荷特点的受力分析;依据机床振动理论构建了导轨滑块运动副粘性阻尼振动模型及其有限元结构模型;采用机床锤击试验模态和机床有限元结构模态相结合的方法验证了包含导轨滑块运动副粘性阻尼系统的有限元机床模型的适用性,并分析确定了机床110Hz内的6阶模态振型及其频率。     

微动工作台线性化精度评价方法研究

并联徼动工作台广泛应用于高精度场合。目前,微动工作台还沿用传统并联机构的精度分析方法,这些方法在应用中无法全面定量地反映出微动工作台的精度,因此有必要对其精度分析和评价方法进行研究。具体以一种六自由度微动工作台为例,利用微分方法得到了输入输出位姿的显示雅克比矩阵,并对线性化方法的精度进行验证。提出了精度系数的概念,利用精度系数判断机器人在应用范围内各种条件下是否会影响其运动精度。误差仿真算例显示该方法是可行的。     

Online tool-wear measurement of small-diameter end mills based on machine vision

The objective of this study was to develop an online tool-wear-measurement scheme for small diameter end-mills based on machine vision to increase tool life and the production efficiency. The geometrical features of wear zone of each end mill were analyzed, and three tool wear criterions of small-diameter end mills were defined. With the uEye camera, macro lens and 3-axis micro milling machine, it was proved the feasibility of measuring flank wear with the milling tests on a 45# steel workpiece. The design of experiment (DOE) showed that Vc was the most remarkable effect factor for the flank wear of small-diameter end mill. The wear curve of the experiments of milling was very similar to the Taylor curve.     

Method with repeated extraction-insertion cycles to improve the needle insertion accuracy

In order to improve the effectiveness of percutaneous diagnosis and therapies,the needle insertion into the deforming soft and inhomogenous tissue should be accurate. In this study a needle with 6 degrees of freedom force / torque sensor is used to find the relationship between the pathway’s length and the force. Our experiments show that the method with repeated extraction-insertion cycles can make the needle approach the target as much as possible. M eanwhile ! a method to obtain the appropriaterepeated extraction-insertion cycles is given to drive the needle to execute the repeated cycles efficiently. Experiments and discussions were conducted to preliminarily validate the method.     

Roundness error evaluation by minimum zone circle via microscope inspection

Utilizing the convex hull theory, a novel minimum zone circle (MZC) method, named improved minimum zone circle (IMZC) was developed in this paper. There were three steps for IMZC to evaluate the roundness error. Firstly, with the convex hull algorithm, data points on the circle contour were categorized into two sets to determine two concentric circles which contained all points of the contour. Secondly, vertexes of the minimum circumscribed circle and the maximum inscribed circle were found out from the previously determined two sets, and then four tangent points for determining the two concentric circles were also found out. Lastly, according to the evaluation using the MZC method, the roundness error was figured out. In this paper, IMZC was used to evaluate roundness errors of some micro parts. The evaluation results showed that the measurement precision using the IMZC method was higher than the least squared circle (LSC) method for the same set of data points, and IMZC had the same accuracy as the traditional MZC but dramatically shortened computation time. The computation time of IMZC was 6.89% of the traditional MZC.     

Fuzzy control method to minimize the needle deflection during needle insertion therapy

A fuzzy control algorithm is adopted to help the needle hit the target more accurately. The experimental setup for the needle insertion is built up to validate the algorithm. How the forces dur- ing the insertion make the needle deflect away from the planned path is given, and the normal meth- od correcting the deflection is obtained accordingly. Because the normal method cannot perform well for correction, a fuzzy controller is established. The input module, output module, fuzzification module, defuzzification module and inference engine for the controller are given respectively accord- ing to the fuzzy theory. Our experimental results show that the fuzzy controlling system presenting in the paper can better eliminate the deflection.