基于图形法的仿生拓扑优化方法

针对图形系统自动生成图形拓扑形式的优势,提出了一种以隐式方式表征结构拓扑形式的分步拓扑优化设计方法。该分步优化方法首先以基结构法（ground structure method）的计算结果为基础,并通过均匀化方法得到设计区域内的离散拓扑信息,利用第一步所得的拓扑数据指导分形系统中每一级新增拓扑结构的生长方向,以类似细胞分裂生长的形式完成整体结构拓扑形式生成。最后以参数化建模方式完成模型的结构有限元的批量计算,并结合进化算法,完成对设计模型的优化。其中第一个案例通过本文仿生方法在多目标优化方法下得到了近似Michell结构的最优拓扑结构,第二个方案中机翼蒙皮的屈曲载荷系数提升了10.61%,并且质量降低了10.85%,验证了本文方法在类平面结构拓扑优化方面的可行性。      

扑翼飞行器驱动机构回顾与展望

扑翼飞行器的驱动机构是扑翼飞行器的动力装置,决定了扑翼飞行器的整机性能。随着人们对扑翼飞行器性能的要求越来越高,各国研究者们对其驱动机构工作原理的探索也越来越深入,从而使扑翼飞行器驱动机构设计理论与方法研究取得了显著进展。在最近几年里,更是涌现出了许多新型高效的驱动机构。本文对近些年出现的传统纯机械式的驱动机构和基于智能材料的驱动机构的应用现状做了详细的研究与总结,并分析了其特点与发展趋势。介绍了柔性结构在扑翼飞行器领域的应用情况,并分析了其在驱动机构中发挥的作用。     

微扑翼飞行器驱动装置设计与动力学性能研究

将压电陶瓷驱动器和柔性铰链四杆放大机构融为一体,设计了结构紧凑的微扑翼驱动装置,并采用粒子群算法完成了微扑翼驱动装置结构参数优化设计;采用拉格朗日方程来建立微扑翼驱动系统动力学模型,对动力学性能进行了仿真研究.研究结果表明:采用正弦驱动电压,微扑翼驱动装置可以实现稳定扑打运动,另外,采用标准正弦驱动电压,在某一频段微扑翼驱动装置能实现高效扑动,而且通过调整驱动电压幅度能够控制扑动幅度.该研究为微扑翼飞行器运动控制奠定了基础.      

微型飞机及其研制的关键技术

微型飞机作为一种新概念的航空器,有着广泛的功能和用途,它的研究面临诸多新技术开发的挑战,本文介绍了与微型飞机设计和其性能有关的一些问题,并进行了深入的探讨,反映了微型飞机研究的新动态。     

一种仿蜜蜂类昆虫扑翼悬停控制的仿真估算研究

基于准稳态气动力模型,推导了仿蜜蜂类昆虫扑翼气动力和力矩估算公式,建立了扑翼运动函数.将仿蜜蜂类昆虫扑翼视为空间运动刚体,在其动力学方程基础上,采用分层控制策略研究悬停控制问题.外层为位置控制,X和Y位置应用PD控制算法,Z位置应用切换控制方法;内层姿态控制采用切换控制方法,并选择了一套机翼运动参数用于切换控制.最后进行了仿蜜蜂类昆虫扑翼悬停控制仿真试验,试验结果表明所设计的控制策略是有效的,一旦昆虫扑翼受到干扰偏离平衡位置后,通过自动调节能够回到平衡位置附近.      

A review of bird-like flapping wing with high aspect ratio

Bird-like flapping-wing vehicles with a high aspect ratio have the potential to fulfill missions given to micro air vehicles, such as high-altitude reconnaissance, surveillance, rescue, and bird group guidance, due to their good loading and long endurance capacities. Biologists and aeronautical researchers have explored the mystery of avian flight and made efforts to reproduce flapping flight in bioinspired aircraft for decades. However, the cognitive depth from theory to practice is still very limited. The mechanism of generating sufficient lift and thrust during avian flight is still not fully understood. Moving wings with unique biological structures such as feathers make modeling, simulation, experimentation, and analysis much more difficult. This paper reviews the research progress on bird-like flapping wings from flight mechanisms to modeling. Commonly used numerical computing methods are briefly compared. The aeroelastic problems are also highlighted. The results of the investigation show that a leading-edge vortex can be found during avian flight. Its induction and maintenance may have a close relationship with wing configuration, kinematics and deformation. The present models of flapping wings are mainly two-dimensional airfoils or three-dimensional single root-jointed geometric plates, which still exhibit large differences from real bird wings. Aeroelasticity is encouraged to consider the nonignorable effect on aerodynamic performance due to large-scale nonlinear deformation. Introducing appropriate flexibility can improve the peak values and efficiencies of lift and thrust, but the detailed conclusions always have strong background dependence.