Kinematics analysis of a novel all-attitude flight simulator

To overcome the kinematic singularity limitation of simulator, which is unavoidable in a three-axis architecture, an all-attitude flight simulator in a four-axis architecture is proposed. The simulator can always provide 3DOF motion by applying redundant manipulator mechanism. For direct kinematics of the manipulator, a dual-Euler method is adopted to solve the expressions of attitude angles; thus computation singularity of all- attitude angles is overcome. For inverse kinematics of the manipulator, pseudo-...     

NUMERICAL ANALYSIS OF THE PERFORMANCE OF HORIZONTAL AND WAVY SUBSURFACE FLOW CONSTRUCTED WETLANDS

A three-dimensional numerical model is proposed for modeling the TP transport in the Horizontal Subsurface Flow(HSSF) and Wavy subsurface Flow(WSSF) constructed wetland in this article.Both numerical simulations and physical experiments indicate that the removal efficiency of WSSF is higher than that of HSSF.The difference of performance in removing pollutants,e.g.,Total Phosphorus(TP),between HSSF and WSSF is numerically analyzed from three interactive aspects,that is,the hydraulic behavior,the substrate a...     

电极设计虚拟干涉检查

介绍了电极设计系统功能模块的设计。根据电极加工的基本原理和特殊要求,利用几何干涉的基本关系,提出了一种新的电极干涉检查原理,使其对电极设计中工具电极和工件之间特殊的接触状态能作出精确判断。通过干涉检查,最终达到提高电极设计精度,缩短产品制造周期的目的。     

Plug-in混合动力汽车能量管理策略全局优化研究

应用动态规划全局优化算法,针对并联式Plug-in混合动力汽车在不同行驶里程下的能量管理策略进行了全局优化研究。结果表明:车辆的行驶里程小于55km时应使用电动机为主的能量管理策略,当车辆的行驶里程大于55km时应使用发动机为主的能量管理策略;在动态规划最优控制下,车辆行驶里程为55km时整车经济性能最佳,行驶里程小于110km时整车平均等价油耗为2.7L/100km,相对于原型车经济性提高了近58%。     

汽车双质量飞轮扭振减振器性能仿真分析与匹配

通过三维实体建模、试验和计算获取的所研究车型动力传动系动力学参数,分别建立了动力传动系在怠速和行驶工况下的扭转振动仿真分析模型,分析了双质量飞轮扭振减振器对动力传动系固有特性及强迫振动响应特性的影响,并对双质量飞轮扭振减振器的主要性能参数进行了设计匹配,该项研究为双质量飞轮扭振减振器的设计匹配提供了参考。     

捷联式制导系统中四元数的计算

推导了捷联式制导系统中四元数微分方程的数值求解方法,分析了误差的传递。为了使计算得到的四元数为单位四元数,构造了保持范数算法和误差自适应校正算法。     

注塑模新型冷却技术及其研究进展

介绍了脉冲冷却、随形冷却、CO2气体冷却等注塑模新型冷却技术的概念和研究现状。从原理的角度出发分析了它们各自的优点及存在的问题,阐述了它们的应用状况。展望了将来注塑模冷却技术的发展趋势。     

多工位级进模运动仿真技术研究

以级进模为例,简要阐述了复杂模具运动仿真系统的相关开发过程。该系统与模具设计系统(PDW)相结合,可以对模具运动过程自动地进行仿真,从而大大地简化了对复杂模具运动进行仿真的前置处理工作。     

外磁场下MIG焊梯度功能材料制备模拟及实验研究

建立了梯度功能材料MIG焊熔积成形制备时磁场环境、焊枪及金属焊样的三维有限元模型.采用Maxwell涡流场及瞬态场对永磁场、交变磁场以及无外加磁场3种MIG焊工艺进行了模拟,并进行了相关实验验证.模拟结果表明,永磁场条件下,熔池受恒定强磁力作用,对熔化金属的搅拌能力弱,无法充分使Al粉和合金钢焊丝融合,不能实现制备梯度功能材料的目的;交变磁场条件下,因熔池受到轴向振荡磁力和横向挤压磁力的共同作用,对熔池的搅拌作用强,有助于梯度功能材料的熔积成形.实验结果与模拟结果符合良好,无磁场条件下,制备出的材料Al含量梯度功能不佳;永磁场条件下,Al粉无法进入焊样中;交变磁场条件下熔积成形的焊样中Al含量呈梯度分布.     

Precise recognition of warhead and decoy based on components of micro-Doppler frequency curves

From the view of electromagnetic scattering,it is indicated that the micro-Doppler (m-D) character-istics of an extended target undergoing micro-motions are actually induced by the change of incident directions of radar pulses.Different micro-motions may lead to similar change of incident directions,consequently inducing similar m-D characteristics.To tackle this problem,rather than distinguish warhead and decoy directly from m-D characteristics,the frequency components of m-D frequency curves are used as a new characteristic for recognition in this paper.To get high precision of frequency components estimation,model-based parameter estimation (MBPE) is utilized to extract the m-D frequency curves from TFR.To obtain high accurate simu-lation results,the backscattered signal simulation is conducted by full-wave numerical method.The simulation results validate the theoretical analysis and the high performance of the proposed method.