滚齿机分度链短周期误差的补偿

以控制理论和时序理论为基础,提出了一种适于生产应用的滚齿机短周期误差动态补偿方法,建立了补偿控制系统。通过实验研究和计算机仿真,认为该方法是可行的和有效的。     

浅析数控机床几何误差及其补偿方法

对数控机床的几何误差产生的原因作了比较详细的分析,将系统误差的补偿方法进行了归纳,并在此基础上阐述了各类误差补偿方法的应用场合,为进一步实现机床精度的软升级打下基础。     

用于油缸测距系统中的误差分析及补偿

给出了超声波测距的基本原理及其在液压油中传播速度的简化公式。分析了简化公式的误差及其在测距中引起的测距误差。并对度越时间进行了补偿。     

孔板式流量计的误差分析及补偿措施

分析了孔板式流量计在煤气流量检测啼生的主要来源，进而计算出补偿公式，提出补偿措施。’     

辊型在线检测中的误差分离与补偿方法研究

对影响辊型在线检测精度的各种因素进行了详细的分析 ,建立了误差分离模型 ,并提出相应的误差补偿方法。将该模型应用于简易模拟工况试验和 1 :1模拟工况试验 ,得到了真实的被测辊型。从试验和分析结果看 ,在制定正确的测量策略和进行精确的数据处理的前提下 ,选用电涡流测距传感器进行辊型在线检测是可行的。     

两种模型在滚齿机传动误差中预报精度的比较

通过计算机模拟误差补偿,从计算预报误差的时间和精度上对两种模型作了比较。指出滚齿机展成链传动误差预报模型应该是时变参数模型,并提出了提高时变参数模型的预报速度,以便实现误差补偿与控制的措施,得到的结论对传动误差的补偿与控制有实际意义。     

基于XK7132数控铣床几何误差补偿技术的研究与应用

三轴数控机床存在21项几何误差,导致机床进给运动时产生空间误差,影响机床的加工精度.通过坐标轴的齐次变换矩阵,建立了XYTZ型三轴数控机床的几何误差模型.通过对数控机床定位误差的测量,并基于数控系统的误差补偿功能,对机床实行反向间隙补偿和螺距误差补偿.补偿结果表明通过对机床定位误差补偿可以有效减小几何误差的不利影响.     

板形仪位置误差补偿模型的研究及应用

 针对冷轧带钢生产实践中板形仪不可避免的位置倾斜问题,根据位置几何关系和板形理论,结合轧机设备的布置特点和带钢轧制参数,分别建立了带钢下卷取和上卷取2种方式的板形仪位置误差的板形补偿模型。以某冷轧机为实例进行分析,分别研究了下卷取和上卷取2种方式下带卷取不同直径时,板形仪的水平位置误差和垂直位置误差对板形的影响,得到了板形仪容许安装的位置误差范围。将板形仪位置误差补偿模型应用于某六辊冷轧机的生产实践中,结果表明稳态时带钢的板形标准偏差控制在5 I以下,显著提高了带钢的板形质量。     

基于深度循环神经网络的协作机器人动力学误差补偿

由于协作机器人的结构比普通工业机器人更为轻巧,一般动力学模型所忽略的复杂特性占比较大,导致协作机器人的计算预测力矩误差较大。据此提出在考虑重力、科里奥利力、惯性力和摩擦力等的基础上,采用深度循环神经网络中的长短期记忆模型对自主研发的六自由度协作机器人动力学模型进行误差补偿。在实验中采用优化后的基于傅里叶级数的激励轨迹驱动机器人运动,以电机电流估算关节力矩,获取的原始数据用来训练长短期记忆模型(LSTM)补偿网络。网络的训练结果和评价指标为预测力矩相比实际力矩的均方根误差。计算与实验结果表明,补偿后的协作机器人动力学模型对实际力矩具有更好的预测效果,各轴预测力矩与实际力矩的均方根误差相比于未补偿的传统模型降低了61.8%至78.9%不等,表明了文中所提出补偿方法的有效性。      

数控加工零件误差原因分析及解决措施

数控加工零件误差包括形位误差和尺寸误差,为了减少误差,必须充分了解其原因,然后据此采用合适的措施,这样能够最大化地减少误差,提高加工精度.     

双重差动机构在滚齿机分齿上的分析与研究

传统的由齿轮链传动的滚齿机难于加工大于 10 0的大质数齿数齿轮 ,而滚切斜齿大质数齿数、大模数齿轮就更困难 ,且生产率十分低 .本文提出的双重差动齿轮机构能有效地实施大质数齿数齿轮的分齿运动 ,大大提高生产率 ,并且只需配备相当于传统滚齿机 1/2的交换齿轮就能满足2 50以下所有齿数齿轮的分度 ,显然这是一种很有价值的分齿机构     

高炉喷煤系统串罐称量补偿的一种有效方法

针对目前造成高炉喷煤系统煤粉称量误差的主要原因———浮罐效应 ,在原理分析的基础上 ,提出了一种实现压力补偿的方法 ,并在实践中获得了较好的效果。     

数控铣床主轴故障分析和处理方法

通过一台国产XK5032数控铣床主轴系统结构原理的分析,指出噪声大、发热和不能装卸刀具等故障的原因,提出在检修中使用自制的简易拔销器和波形弹簧压缩等工具,总结了数控机床机械故障诊断和维修的一些经验.     

新型非对称齿轮滚刀设计理论与方法

从齿轮啮合和滚刀设计的基本原理出发,提出了非对称渐开线圆柱齿轮滚刀的设计方法,推导了相应的计算公式,给出了计算实例,实现了非对称齿轮滚刀的参数化实体模型.根据齿轮加工原理,分别用面向对象的Visual Basic和Autolisp语言对非对称齿轮范成加工进行参数化编程,模拟仿真了非对称齿轮加工的包络过程.     

Use of superhard nonmetallic materials for making machine parts and tools

Translated from Metallurg, Vol. 39, No. 12, pp. 30–31, December, 1995.     

A method for motion compensation of a moving nematode Caenorhabditis elegans and its application to frequency analysis of pharyngeal pulsation

A new sequential image processing method for motion compensation of a moving object with stringy shape has been developed for estimating the pharyngeal pulsation of the nematode Caenorhabditis elegans under several environmental conditions. The method is based on the pixel data transfer on a new image frame while changing the boundary shape and the position but preserving the conformation of the inner structure of an object. All digitized image frames of C. elegans were first converted to motion-compensated images to arrange the pulsation site in the same region of the every transformed frame. The pulsation site was then automatically detected by determining the pixels where the temporal brightness variation was much larger than that of the other pixels. Finally, the pulsation frequency was determined by the Fourier analysis. The validity of our method has been confirmed by analyzing various test data, and the method has been applied for detecting the pharyngeal pulsation frequencies of C. elegans on some environmental conditions, i.e. feed bacteria-free/rich, doping of nerve inactivating ethyl-alcohol and nerve stimulant neurochemical substance of serotonin. The motion compensation method automatically provided reasonable pulsation frequencies which were found to be comparable to those obtained by manual counting. Thus the method is useful for systematic investigations on the variation of pharyngeal pulsation associated with the activity change of the nervous system in environments.     

Image manipulation and error estimation for MRI analysis

This trial was designed to compare foscarnet with ganciclovir as pre-emptive therapy for CMV infection in patients undergoing allogeneic hemopoietic stem cell transplant (HSCT). Thirty-nine patients were randomized to receive foscarnet 90 mg/kg every 12 h (n = 20) or ganciclovir 5 mg/kg every 12 h (n = 19) for 15 days at the time of development of CMVAg-emia. Primary-end points of the study were (1) outcome of CMVAg-emia; (2) progression to CMV disease; and (3) side-effects of treatment. The secondary end-point was transplant-related mortality (TRM). The two groups were comparable for diagnosis, status of disease, donor type, acute graft-versus-host (aGVHD) prophylaxis, interval between HSCT and CMVAg-emia and number of CMVAg positive cells; the donor and recipient age were borderline older in the foscarnet group. Increments of serum creatinine in the foscarnet group, and cytopenia in the ganciclovir group were controlled by reducing the administered dose: in the first 15 days of therapy 9/20 foscarnet and 10/19 ganciclovir patients had a dose reduction greater than 20% (P = 0.43). Clearance of CMVAg-emia was faster in the foscarnet group although with borderline statistical significance. Failures of treatment occurred in 3/20 patients in foscarnet group vs 8/19 patients in ganciclovir group (P= 0.06): causes of failure were the need for combination therapy to control antigenemia (1/20 vs 5/19), and reactivation during treatment for 2 vs 3 patients, respectively. CMV disease was diagnosed in 1 vs 2 patients (P = 0.5) who subsequently died. The actuarial 1-year TRM was 25 vs 12%, respectively (P = 0.3). This study suggests that foscarnet and ganciclovir are both effective for pre-emptive therapy of CMVAg-emia, although the number of failures would seem to be slightly higher in the ganciclovir patients. Side-effects are seen in both groups and can be managed with appropriate dose reduction.