基于空间杆—锥式对接机构的柔性杆技术研究

发布时间：2018-03-24 03:17

本文选题：柔性杆　切入点：对接碰撞　出处：《国防科学技术大学》2011年硕士论文

【摘要】：柔性杆应用于杆-锥式对接碰撞过程属于柔性多体动力学问题,其中还涉及到比较复杂的碰撞瞬态动力学研究,因此具有较大的研究难度。迄今,柔性多体碰撞动力学问题研究仍停留在研究的初级阶段,深入研究工作具有较大的挑战性。本文以含斜碰撞的柔性多体动力学系统作为研究对象,采用理论建模、仿真计算和地面原理实验相结合的方法,通过对柔性杆对接碰撞动力学过程建立理论模型,对柔性杆碰撞过程中的频率特性及振动特性进行仿真分析,对空间杆-锥式对接机构对接过程进行地面实验模拟等研究,较全面地揭示了柔性杆应用于杆-锥式对接碰撞过程中所涉及的复杂非线性动力学行为。论文主要研究内容及学术贡献如下: (1)柔性杆对接碰撞动力学过程建模方面,采用Lagrange分析力学方法来解决其中涉及的多体动力学问题,利用模态叠加法来对碰撞过程中柔性杆的变形进行描述,利用Hertz点-面接触模型来解决碰撞力求解问题,最终得到了可以合理描述柔性杆对接过程首次碰撞的动力学模型。 (2)柔性杆对接碰撞过程有限元建模及动力学仿真分析方面,通过对仿真结果的时/频域分析,找出了柔性杆碰撞频率特性与柔性杆振动模态之间的关系;通过有限元方法与理论模型输出结果的比较分析,验证了理论模型在描述首次碰撞问题上的正确性;通过改变柔性杆弹性模量,得到了碰撞力峰值、碰撞持续时间与碰撞过程冲量随弹性模量的对数关系。 (3)基于杆-锥式对接机构的地面碰撞实验系统设计方面,给出了地面碰撞实验总体设计方案,其中包括实验系统的组成、实验流程、实验样机及相关器件设计;通过仿真建模分析,对加速度传感器的选择方法进行了较为详细的介绍;给出了利用加速度传感器测量对接碰撞力的测量方法及数据处理方法;通过对实验结果的分析,一方面验证了实验方法的合理性,另一方面也验证了理论模型在描述首次碰撞问题上的正确性。 (4)柔性杆结构设计方面,在柔性杆对接碰撞理论模型基础上开展相关结构优化工作,采用遗传算法得到一种对接杆的优化结构,通过有限元方法将普通直线对接杆与经过结构优化对接杆的缓冲性能进行了比较分析,验证了优化结果的有效性。通过大胆假设,探讨了两种大变形对接杆的缓冲性能,其中有效结合了Pro/E与MSC.Patran/Dytran两种软件相互之间的优点,实现了对两种复杂对接杆模型的建模与有限元瞬态动力学仿真,通过仿真结果比较了大变形杆与普通直杆缓冲性能之间的差异,得到了一些很有价值的结论。在这些结论的指导下,设计出弹簧-软质杆组合结构对接杆,并且通过地面碰撞实验的方法验证了组合对接杆与普通软质直杆之间的性能差异。
[Abstract]:The flexible rod applied in the rod-cone docking collision process belongs to the flexible multi-body dynamics problem, which also involves the relatively complex research of the collision transient dynamics, so it is difficult to study. The study of flexible multi-body collision dynamics is still in the primary stage, and the further research work is challenging. In this paper, the flexible multi-body dynamics system with oblique impact is taken as the research object. The theoretical model of the flexible rod docking collision dynamic process is established by using the method of theoretical modeling, simulation calculation and ground principle experiment. The frequency and vibration characteristics of flexible rod collision are simulated and analyzed, and the ground experiment simulation of the docking process of space rod-cone docking mechanism is carried out. The complex nonlinear dynamic behavior involved in the application of flexible rod in the rod-cone docking collision process is fully revealed. The main research contents and academic contributions in this paper are as follows:. 1) in the aspect of modeling the dynamic process of flexible rod docking and collision, Lagrange analytical mechanics method is used to solve the multi-body dynamics problem involved, and the modal superposition method is used to describe the deformation of flexible rod during the collision process. The Hertz point-surface contact model is used to solve the collision problem. Finally, a dynamic model which can reasonably describe the first collision of flexible rod docking process is obtained. 2) in the aspect of finite element modeling and dynamic simulation analysis of flexible rod docking collision process, the relationship between the frequency characteristic of flexible rod collision and the vibration mode of flexible rod is found out by analyzing the simulation results in time / frequency domain. The correctness of the theoretical model in describing the first impact problem is verified by comparing the output results of the finite element method and the theoretical model, and the peak value of the impact force is obtained by changing the elastic modulus of the flexible rod. The logarithmic relationship between impact duration and impulse of collision process with elastic modulus. 3) the overall design scheme of the ground impact experiment system based on the rod-cone docking mechanism is presented, which includes the composition of the experimental system, the experimental flow, the experimental prototype and the design of the related devices. Through simulation modeling and analysis, the selection method of acceleration sensor is introduced in detail, and the measuring method and data processing method of using acceleration sensor to measure docking collision force are given. On the one hand, the rationality of the experimental method is verified, on the other hand, the correctness of the theoretical model in describing the first collision problem is also verified. In the aspect of flexible rod structure design, the related structural optimization work is carried out on the basis of flexible rod docking collision theory model, and a kind of optimal structure of docking rod is obtained by genetic algorithm. Through finite element method, the buffering performance of ordinary straight docking rod and structural optimized butt rod is compared and analyzed, and the effectiveness of the optimization result is verified. The buffering performance of two kinds of large deformation docking rod is discussed through bold assumptions. Combining the advantages of Pro/E and MSC.Patran/Dytran software effectively, the modeling and finite element transient dynamics simulation of two kinds of complex docking rod models are realized. Through the simulation results, the difference between the buffering performance of large deformable rod and ordinary straight rod is compared, and some valuable conclusions are obtained. Under the guidance of these conclusions, the spring and soft bar combination structure docking rod is designed. The performance difference between the combined butt rod and the ordinary soft straight rod is verified by the ground impact test.
【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH113

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