基于并联机构的多自由度力加载系统研究

发布时间：2018-03-17 09:18

本文选题：并联机构　切入点：六维力加载　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：航天器在太空飞行过程中,空间对接机构起到了连接各舱体的至关重要的作用。为了维持航天器稳定的飞行状态,空间对接机构组合体将会长时间承受多个自由度方向的力和力矩。为了保证对接机构组合体在轨运行时的可靠性,在对空间对接机构的设计过程中,需要在地面进行对接机构组合体多自由度加载疲劳测试。本课题以对接机构组合体疲劳寿命试验台项目为依托,对并联多自由度力加载试验系统进行了研究。不同于以往大多数的多维力加载系统,本文的创新之处首先在于设计并验证了一个全新的并联加载结构,并设计了基于驱动力闭环的控制方法,通过反解对接机构组合体受到的力和力矩,求出各加载液压作动器所要输出的力,通过精确控制各加载液压作动器的输出力来实现对接机构组合体的疲劳加载;本文另外一个创新点为通过仿真软件分析了负载刚度变化对多自由度加载系统的加载性能的影响,并且模拟了加载系统加载力的耦合特性,对科研项目以及工程实践具有指导性的意义。本文首先介绍了基于正交六自由度并联平台的多轴加载系统的基本构造以及加载原理。根据性能指标要求所设计的这种正交并联机构可以同时向对接机构组合体精确施加给定的六个自由度的力和力矩。其次,针对所采用的加载机构的机械结构,建立了加载系统的运动学模型,然后进一步求解出了其动力学方程,并且利用Matlab Simulink软件建立了多自由度加载系统的六维力和力矩的反解模型。之后,本文对加载液压作动器力闭环系统进行了建模和分析,建立了阀控液压缸驱动力闭环系统的详细模型,并对力闭环系统进行了仿真分析。设计了单缸力闭环控制器以提高驱动力闭环控制系统的稳定性。为了建立本文所研究的并联加载系统的完整模型,本文利用动力学仿真软件ADAMS对加载系统的机械系统进行了建模,并且利用模拟负载代替对接机构进行仿真分析。最后利用Matlab软件和ADAMS软件对所研究的并联六维力加载系统进行了联合仿真分析。实现了该并联多轴加载系统的静态和动态加载仿真,并且分析了对接机构刚度的变化对整个系统的影响,分析了该并联多轴加载系统各自由度间力耦合特性,为今后的力解耦控制研究奠定了一定的基础。
[Abstract]:During the space flight, the space docking mechanism plays an important role in connecting the various cabin bodies. In order to maintain the stable flight state of the spacecraft, In order to ensure the reliability of the docking mechanism in orbit operation, the space docking mechanism is designed in the process of designing the space docking mechanism, in order to ensure the reliability of the docking mechanism in orbit, the space docking mechanism assembly will bear the force and torque of multiple degrees of freedom for a long time. It is necessary to carry out multi-degree of freedom loading fatigue test of docking mechanism assembly on the ground. This subject is based on the fatigue life test bench project of docking mechanism assembly. This paper studies the load test system of parallel multi-degree-of-freedom forces. Different from most of the previous multi-dimensional loading systems, the innovation of this paper lies in the design and verification of a new parallel loading structure. A closed-loop control method based on driving force is designed, and the output force of each loaded hydraulic actuator is obtained by solving the force and torque of the butt joint assembly. The fatigue loading of the docking mechanism assembly is realized by accurately controlling the output force of each loaded hydraulic actuator. Another innovation of this paper is to analyze the influence of the load stiffness change on the loading performance of the multi-degree-of-freedom loading system through the simulation software. And the coupling characteristics of the loading force of the loading system are simulated. This paper first introduces the basic structure and loading principle of multi-axis loading system based on orthogonal six-degree-of-freedom parallel platform. This kind of orthogonal parallel mechanism can precisely apply the force and torque of a given six degrees of freedom to the docking mechanism assembly at the same time. Secondly, According to the mechanical structure of the loading mechanism, the kinematics model of the loading system is established, and the dynamic equation is solved. The inverse solution model of the six dimensional force and torque of the loading system is established by using Matlab Simulink software. After that, the force closed loop system of the loaded hydraulic actuator is modeled and analyzed. A detailed model of the driving force closed-loop system of the valve controlled hydraulic cylinder is established. A single cylinder force closed-loop controller is designed to improve the stability of the driving force closed-loop control system. In order to establish the complete model of the parallel loading system studied in this paper, In this paper, the dynamic simulation software ADAMS is used to model the mechanical system of the loading system. Finally, Matlab and ADAMS software are used to simulate and analyze the parallel six-axis loading system. The static state of the parallel multi-axis loading system is realized by using the simulation load instead of the docking mechanism. State and dynamic loading simulation, The influence of the stiffness of the docking mechanism on the whole system is analyzed, and the coupling characteristics between the various degrees of freedom of the parallel multiaxial loading system are analyzed, which lays a foundation for the future study of the force decoupling control.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V416.8

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