一种基于模糊控制的推力变向机构控制仿真

为了适应越来越恶劣的飞机作战环境,在原有的轴对称矢量喷管的数学模型的基础上,提出一种基于模糊控制的推力变向机构的构想.建立AVEN的数学模型,并进行模糊控制设计,通过Matlab的仿真说明该控制器可以有效地追踪输入信号的变化,同时进一步分析比较量化因子Ke、Kde和比例因子Ku对控制结果的影响,在此基础上设计模糊PID控制器,与单纯的PID控制器和模糊控制器进行比较.分析结果表明:该模糊控制器能够较为理想地跟踪输入,较为准确地分析各量化因子对输出结果的影响,为推力变向机构的工程实践提供理论参考.     

激光二极管线列阵与多模光纤列阵的光纤耦合

利用一段数值孔径(NA)较小的多模光纤作为一个低成本的微透镜,对激光二极管线列阵的大数值孔径方向准直,将激光二极管线列阵的输出光束耦合到多模光纤列阵中.激光二极管线列阵每个发光单元的光分别耦合到光纤列阵的单根光纤中.总的耦合效率和输出光功率分别为75%和15W.     

超长、超宽建筑物施工测量整体控制技术

国家会议中心工程超长,超宽,施工周期较长,测量精度标准要求高,常规测量手段难以满足要求。在施工现场布设两级控制网的测量方案,使建筑物的整体精度得到保障。超长轴线的投测采用独特的两点间恢复直线的测量方法,既满足施测精度,又提高测量效率。建筑物轴线竖向传递采用首层布设内控点,使用激光铅直仪进行传递的方法,满足细部轴线的测设精度。     

非正交轴系“激光经纬仪”视准轴校正方法

非正交轴系“激光经纬仪”(简称非正交轴 系经纬仪)在长时间的使用过程中视准轴参数发生微小的变化将会严重影响 测量精度,因此有必要对视准轴的参数进行校正。本文提出了一种基于非正交 轴系经纬仪前 方交会原理的视准轴参数校正方法,首先利用交会约束建立关于视准轴参数的非线性方程 组,然后通过 解方程组得到校正后的参数。为了验证方法的正确性,使用SolidWorks建立模型并 结合OpenGL 进行了仿真计算,然后进行了相应的实验。结果表明,本文方法能有效校准视准轴参数, 且具有很高的 精度;用本文方法对视准轴进行校正后,非正交轴系经纬仪测量系统的测量精度没有受到 影响。由于本文 校正方法不需要借助其他辅助仪器且校正过程简单,故可以在测量现场对视准轴进行实时 校正,具有一定的实用性。     

五轴框架式机器人激光加工系统轨迹算法研究

在集成化智能激光加工系统工作原理的基础上提出了五轴机器人的激光加工轨迹算法。将三维离散数据点集拟合为空间参数曲面 ,在此参数曲面上规划五轴激光加工的等距轨迹。给出了冲压模具激光强化加工实例 ,取得了理想的加工效果。     

红外目标与干扰模拟器光学系统研究

介绍了带有两个干扰的红外目标与干扰模拟器的光学系统;它采用两个黑体分别作为红外目标和干扰模拟辐射源,通过两个摆镜产生两个不同方向、不同速度和不同时间的干扰。     

Optimum design of mounting components of a mass property measurement system

Measurement of inertia properties of aerospace vehicle and submarine are vital to meet the intended motion objectives. The Moment of Inertia (MOI) is calculated by measuring the frequency of free torsional oscillation of the object mounted on a nearly friction less air bearing. For getting accurate measurement and to nullify the effect of undesired vibrations, the stiffness of the different components of the mounting and fixture (torsion rod, flexure) should be maintained appropriately. The optimum design of torsion rod and flexure is based on ensuring desired natural frequencies in different modes. Initiating with an analytical approach, the actual dimensions of the components are determined based on natural frequencies obtained by finite element analysis of the components. Simulated results are verified with experimental results.     

Influence of blade deformation and yawed inflow on performance of a horizontal axis tidal stream turbine

For a better design of tidal stream turbines operated in off-design conditions, analyses considering the effects of blade deformation and yawed inflow conditions are necessary. The flow load causes deformation of the blade, and the deformation affects the turbine performance in return. Also, a yawed inflow influences the performance of the turbine. As a validation study, a computational fluid dynamics (CFD) simulation was carried out to predict the performance of a horizontal axis tidal stream turbine (HATST) with rigid blades. The numerical uncertainty for the turbine performance with blade deformation and a yawed inflow was evaluated using the concept of the grid convergence index (GCI). A fluid–structure interaction (FSI) analysis was carried out to estimate the performance of a turbine with flexible composite blades, with the results then compared to those of an analysis with rigid blades. The influence of yawed inflow conditions on the turbine performance was investigated and found to be important in relation to power predictions in the design stages.     

Experimental investigation,prediction and optimization of cylindricity and perpendicularity during drilling of WCB material using grey relational analysis

Manufacturing is always the heart of majority of industries. Drilling is an extremely important and an essential machining process which requires a lot of attention as in most of the cases it is required for assembly purposes. Majority of the holes produced during drilling are made with the help of Vertical Machining Centre (VMC) meant for pin- hole assembly. Though the tolerance is within limit, assembly problems arise due to the improper geometry of these holes. Various geometrical tolerances like cylindricity, circularity, perpendicularity and position errors are responsible for such assembly problems. This investigation is focussed on cylindricity and perpendicularity in the drilling of Wrought Cast Steel Grade B (WCB) material using SOMX 050204 DT insert. In this work, effect of machining variables like cutting speed, feed rate and depth of cut (canned cycle) are investigated and optimized using grey relational analysis (GRA). Reliable experiments are conducted based on a 3³ full factorial, replicated twice. Second order regression models are developed for predicting cylindricity and perpendicularity. The models’ adequacy has been checked by calculating correlation coefficient. It shows that the developed models are well fitted for the prediction of responses within the specific range of input variables.     

FANUC RAM轴在数控伺服冲床上的应用

在FANUC Oi PD数控系统的基础上,把RAM轴功能应用在数控伺服冲床上,通过模拟伺服适配器控制第三方驱动器和电机,选择M信号来指定冲压轴所处的动作模式,控制冲头上下移动的形式、速度,降低冲压噪声,提高效率。