双转台五轴数控加工空间孔的坐标偏置算法建模

根据空间几何理论建立了双转台五轴数控加工空间孔的中心坐标偏置算法模型,利用该模型可以计算出要加工的空间孔随着工作台旋转和摆动后孔口中心在参考坐标系下的坐标,然后利用数控系统的基准偏置功能将参考坐标系的原点偏置到该点,从而可以建立易于空间孔编程的、新的参考坐标系。     

直线插补在回转类零件周向槽铣削中的应用

利用旋转第四轴、宏程序指令编程和G01直线插补编程,提出了实现某些回转类零件外周曲面上的规则槽、螺旋槽、异形槽以及各种凸轮的加工方法。用凸轮加工实例对提出的加工方法进行仿真验证,获得了较好的加工精度,证明了此方法正确可行。     

坐标转换误差对差分GPS测量精度的影响

分析了差分GPS测量中采用简易坐标转换方法，其两坐标系点平移、坐标轴旋转和尺度不一致参数对定位结果的影响，指出了不同条件下应采用的坐标转换方法，对GPS在试验场的应用具有一定的指导意义。     

复合轧辊喷射铸造成形坐标跟踪法数值模拟分析

通过计算机模拟,采用跟踪复合轧辊表面轮廓线坐标的方法(坐标跟踪法),计算复合轧辊在不同时刻的形状和尺寸.并分析各种喷射铸造工艺参数对复合轧辊形状的影响规律,模拟结果表明,辊芯平移速度和辊芯半径的变化对复合轧辊的沉积层厚度影响较大,而辊芯旋转速度和喷射距离的单独变化对轧辊沉积厚度影响很小.     

数控车床长度补偿功能的使用研究

数控车床上坐标指令（G92、G54～G59）与刀具长度补偿功能（Txxyy,调用xx号刀具和yy号刀补）不能同时使用,当调用后者时,前者指定的工件原点自动失去作用,与数控铣床上两者的使用方法不同.数控车床的对刀方法有其特殊性.本文介绍数控车床上对刀操作,长度补偿值的设置方法,说明长度补偿与编程坐标系原点的关系,长度补偿功能的使用技巧.     

在内圆磨床上成批加工坐标孔

在精密机械产品中,表面硬度高、又有位置度要求的坐标孔,常规方法是热处理后在坐标磨床上进行加工。但坐标磨床价格昂贵,也不适合批生产要求,且许多工厂尚无此种设备。 我们在生产一种液压伺服阀时,就遇到如图1所示的一组孔。其表面渗碳淬火后硬度为HRC55～60。我厂无坐标磨床,只得在普通内圆磨床上加工。     

数控系统中空间任意平面圆弧插补算法

以往的数控系统只能插补平行坐标平面的圆弧,本文根据坐标系旋转的原理,提出了一种可以插补任意平面圆弧曲线、且可以满足控制实时性要求的插补算法,以简化编程,提高加工精度。     

潜射导弹发射原点测量方法

潜射导弹试验发射坐标系的原点一般应取在发射时刻(弹动时刻)导弹质心位置,这就需要高精度的水下定位测量系统。本文提出在不具备水下高精度测量能力的条件下,利用水上测量手段,对发射原点进行“靠近”测量并予以修正的方法。通过计算给出发射时刻导弹质心的大地坐标,应用于潜射导弹试验中。     

多光幕交汇测量弹丸立靶坐标方法研究

首先分析利用CCD测量立靶坐标的基本原理,指出其中存在的问题。在此基础上,提出了一种新的测量方法,利用6个光幕在空间交汇组成光幕阵列,根据飞行弹丸穿过光幕阵列的时刻和测量系统的结构参数,计算出立靶坐标。分析了该方法的测量原理,对测量精度进行仿真计算,依据该方法的技术特点和仿真结果讨论其工程应用前景。     

基于多传感器信息融合的物体位姿检测方法

 提出了利用摄像机和超声传感器信息融合对机器人操作对象进行位姿检测的方法。该方法通过单幅图像获取目标点在图像中的理想坐标,求得投影矢量的方向,然后通过机器人末端的运动,导引超声传感器坐标原点与未移动前摄像机坐标系的原点重合,而其Z轴方向与求得的投影矢量方向相同,再由超声传感器测出投影矢量的长度,从而确定目标点在摄像机坐标系中的坐标,并可进一步转换到机器人基坐标系中。通过测量操作物体上两点的空间坐标,就能够确定物体空间姿态。该方法简单易行,计算量小,精度较高。     

基于飞行仿真平台的相关坐标变换模型

飞行力学中相关的飞行器运动方程都是在地面坐标系中建立的,地面坐标系的前提假设"平面大地"与地球表面具有曲率不符,经纬度能真实反映飞行器的飞行情况,但不能直接运用于飞行器运动方程.针对以上情况,提出了能够运用于地面坐标与经纬度相互转换的模型.在飞行仿真平台上,由飞行器运动方程建立相关的飞行机动动作模型,再由提出的坐标变换模型将运动方程中的相关参数转换为经纬度.实验结果表明,坐标变换模型是合理的,具有实用性,能运用于相关的飞行仿真平台中.     

五轴数控加工中心数学模型的建立与实现

多轴加工时,数控软件生成的刀位文件中既包含刀具刀尖点的坐标值,也包含刀轴方位的方向矢量,因此后置处理程序需要将刀位文件中的刀位轨迹坐标转换为机床坐标及相应的回转角度.针对一种五轴数控加工中心,用数学描述的方法建立其坐标变换的数学模型,讨论BC两角可能出现的几种情况,从而解决了其数据转换的问题.在此基础上,利用C 语言开发本模型相应的后置处理程序.实验证明该模型是切实可行的.     

Investigation of anode shaping process during co-rotating electrochemical machining of convex structure on inner surface

A novel co-rotating electrochemical machining method is proposed for fabricating convex structures on the inner surface of a revolving part. The electrodes motion and material removal method of co-rotating electrochemical machining are different from traditional electrochemical machining. An equivalent kinematic model is established to analyze the novel electrodes motion,since the anode and cathode rotate in the same direction while the cathode simultaneously feeds along the line of centres. Acc...     

Convex shaping process simulation during counter-rotating electrochemical machining by using the finite element method

In counter-rotating electrochemical machining(CRECM), a revolving cathode tool with hollow windows of various shapes is used to fabricate convex structures on a revolving part. During this process, the anode workpiece and the cathode tool rotate relative to each other at the same rotation speed. In contrast to the conventional schemes of ECM machining with linear motion of a block tool electrode, this scheme of ECM is unique, and has not been adequately studied yet. In this paper, the finite element method(FEM) is used to simulate the anode shaping process during CRECM, and the simulation process which involves a meshing model, a moving boundary,and a simulation algorithm is described. The simulated anode profiles of the convex structure at different processing times show that the CRECM process can be used to fabricate convex structures of various shapes with different heights. Besides, the variation of the inter-electrode gap indicates that this process can also reach a relative equilibrium state like that in conventional ECM. A rectangular convex and a circular convex are successfully fabricated on revolving parts. The experimental results indicate relatively good agreement with the simulation results. The proposed simulation process is valid for convex shaping prediction and feasibility studies as well.     

Dynamics Model of Carrier-based Aircraft Landing Gears Landed on Dynamic Deck

In order to study the carrier-based aircraft landing laws landed on the carrier, the dynamics model of carrier-based aircraft landing gears landed on dynamic deck is built. In this model, the interactions of the carrier-based aircraft landing attitude and the damping force acting on landing gears are considered, and the influence of dynamic deck is introduced into the model through the deck normal vectors. The wheel-deck coordinate system is put forward to solve the complex simulation problem of force-on-wheel which comes from the dynamic deck. At last, by simulation, it is demonstrated that the model can be applied to landing attitude when the carrier-based aircraft is landing on the dynamic deck, it is also proved that the model is comprehensive and suitable for any abnormal landing situation.     

柱坐标系下叶片曲面造型方法的研究

由于叶片在沿叶高方向上截面内的截线不是单值函数,所以需要用参数样条的方式构造整个叶片曲面。在分析叶片沿叶高方向上截面数据的基础上,本文将笛卡儿坐标系下的截面数据转换到柱坐标系下,并以极角和叶高为参数构造了双三次插值B样条曲面。     

多坐标系下目标跟踪的联合滤波

针对雷达目标观测和处理在不同的坐标系下完成，本文提出了联合滤波算法来跟踪机动目标。该算法以卡尔曼滤波器为基础，直角坐标系下和极坐标系下的算法相联合，不仅克服了两种坐标系下滤波算法的不足，而且对机动目标有很好的跟踪效果。仿真实验结果表明了该算法的有效性。     

Dual Drive Curve Tool Path Planning Method for 5-axis NC Machining of Sculptured Surfaces

The problem of finished surface being not first-order continuous commonly exists in machining sculptured surfaces with a torus cutter and some other types of cutters. To solve this problem, a dual drive curve tool path planning method is proposed in this article. First, the maximum machining strip width of a whole tool path can be obtained through optimizing each tool position with multi-point machining (MPM) method. Second, two drive curves are then determined according to the obtained maximum machining strip width. Finally, the tool is positioned once more along the dual drive curve under the condition of tool path smoothness. A computer simulation and cutting experiments are carried out to testify the performance of the new method. The machined surface is measured with a coordinate measuring machine (CMM) to examine the machining quality. The results obtained show that this method can effectively eliminate sharp scallops between adjacent tool paths, keep tool paths smooth, and improve the surface machining quality as well as machining efficiency.     

基于双谱相位算法的无人机图像定位研究

由于传统的定位方法都有不同程度的缺陷,如GPS导航或者捷联惯导,所以借助图像匹配技术实现无人机导航定位具有重要研究意义。双谱中只提取相位信息,形成基于相位谱的算法,能很好地抑制不均匀的光照度变化等。首先以对数-极坐标方式进行相位谱的采样处理,然后由相位相关算法获取尺寸和旋转校正值。校正之后,再由相位相关算法进行2幅图像之间的平移配准。仿真结果验证了该算法不仅有很高的配准精度,而且有很强的稳健性。     

轴流压气机失速特征识别

为了能够准确识别压气机旋转失速过程中失速团的数目,将压气机旋转失速过程中脉动压力波动的相位和幅值特征绘制在极坐标中,然后根据其在极坐标图中表现出来的特征来确定失速团的数目.经过与传统方法对比说明该分析方法对于失速团数目的确定优于原有的方法,具有抗噪性和一定的精度.另外,使用该方法可以可视化周向失速分布区域,并能可视化压气机失速先兆的发生和发展.