【作者】 张大鹏；

【导师】 刘荣强；

【作者基本信息】 哈尔滨工业大学 ， 机械设计及理论， 2008， 硕士

【摘要】 升降式着陆梯的相关研究紧紧围绕探月二期工程的关键技术—月球软着陆和月球车释放技术,对月球表面无人探测任务的顺利实施有着重要意义。目前在探月二期工程的技术论证过程中,国内相关部门已经提出了月球车以及腿式着陆器的初步方案,月球车、着陆器的结构以及月球表面复杂的环境条件要求着陆梯的设计过程遵循轻质、可靠、节能的设计原则。在方案研究阶段,详细比较已有着陆梯结构形式的优缺点之后,建立了PRO/E三维模型并绘制了工程图,以验证新式着陆梯各部件空间布置和加工制造的可行性,从而发展了升降式着陆梯在运动导向性、驱动方式多样性等方面的特点,最后提出了满足发射、承载、着陆等工作阶段各种不同要求的设计方案。在确定设计方案后,运用由整体到局部的结构最优化思想,首先利用Hypermesh建立了承力结构在整个空间的总体有限元模型和结构简化模型,接着依次采用二维拓扑优化、参数优化、三维拓扑优化等方法,设计出重量轻、刚度大的承力结构,实现了“轻量化”的设计目标。为了节约使用航天器上有限的能源,提出了零能耗制动的方法,充分利用直流电机的四象限运行特性,使作为负载的月球车、电机和制动器组成的闭环回路实现稳态运行。然后在动力学仿真过程中,综合运用ADAMS和MATLAB中的仿真工具,模拟升降式着陆梯在钢丝绳作用下由折叠到展开,以及由着陆器顶端下降到底部并最终抵达月面的复杂动力学过程,改变电气参数进行重复实验,以获得期望的着陆速度。最后采用有限元分析方法,依次分析了主要承力结构的静应力、热应力和固有频率,得出了改善其力学性能的基本思路。同时本文建立的参数化3D模型具有一定的通用性,较好地结合了单个零件的应力分析以及整体的动态性能分析,可方便地拆分为独立的子系统或单个元件,以揭示单个部件的性能指标对整体功能的影响,为进一步的MDO优化打下了基础。更多还原

【Abstract】 Relative research of elevator-like landing ladder focus on the key technologies of Lunar Exploration Second Period Project - the moon soft landing technology and the release of lunar rover, is of great significance to make sure the project’s implementation. At present, in the technology demonstration process of Lunar Exploration Second Period Project, the related domestic sector has put forward the initial plan of legged lander. Lunar Rover Lander’s special structure and the complex environmental conditions of the moon asked that, the structure design of elevator-like lander ladder must satisfy the light, reliabe and energy-efficient design requirements.In the conceptual design stage, by comparing the advantages and disadvantages of the lander’s different loading mode and the structure topology of landing ladder, we established 3-D engineering model in PRO/E and CAD drawings to validate new elevator-like landing ladder’s space arrangement and manufacture’s feasibility. So that we synthetically applies structure topology optimization and parameter optimization method, in order to reduce the weight of major bearing structure as much as possible. Around the design objectives of“light weight”, this article focus on the development of elevator-like landing ladder’s efficiency on the direction of movement, its diversity of driven approach, and such the advantages, and has formed a preliminary design plan.After determining the design, as a whole by the use of the localized structural optimization of thought, first of all, establish load-bearing structure’s finite element model and primary model of the overall structure, followed by the use of two-dimensional topology optimization, parametrical optimization, three-dimensional topology Optimization and so on, come to the design of light weight, large stiffness of load-bearing structure to achieve a "lightweight" design goalTo conserve energy of the limited energy resources on spacecraft, a zero-energy braking method is proposed in the third chapter, in order to make full use of the DC characteristics of the four-quadrant operation, so that lunar rover, electrical and brake components can be included in the closed-loop circuit to achieve steady-state run. Then in the dynamic simulation, motion and driving components and connector library of ADAMS, control system library of MATLAB-Simulink are both used to simulate landing ladder’s movements pulling by a rope from folding statement to developed statement and from top of the ladder to the bottom, then change the electrical parameters to repeat the experiment in order to obtain the desired landing speed.Finally, using finite element method, analyze static stress, heat stress and natural frequency of load-bearing structure, then come to many improvements of their mechanical properties of the basic ideas. At the same time, make the parametrical 3D model universal and versatile, so that the stress analysis as well as the overall dynamic performance analysis of individual parts can be combined perfectly and the entire model above aimed for design and optimization can be easily split into various subsystems or components. These characteristics lay the foundation for further MDO.更多还原