计入铰链间隙和构件柔性的关联机构动力学分析

发布时间：2018-05-07 09:36

本文选题：并联机构 + 柔性　；参考：《郑州大学》2012年硕士论文

【摘要】：并联机构加工制造与安装过程的误差和长期运动过程中的磨损,会使机构本身的链接部位产生间隙；同时并联机构中的杆类零件是细长杆,会做大挠度运动,有必要将其视为柔性杆。铰链间隙和构件柔性都会对并联机构的动力学性能产生影响,这些影响会造成机器运行过程中的振动与噪声、使磨损加剧、降低工作效率与输出精确度,严重时会使机构无法正常运行。因此,在分析并联机构动力学性能时,要考虑铰链间隙以及杆类零件柔性的影响。本文首先对考虑间隙和柔性的三自由度并联机构多体系统动力学的研究背景和发展现状进行了系统的综述,通过分析现有研究中在的问题,提出本课题研究的主要内容；其次在系统介绍间隙机构动力学分析方法的基础上,根据并联机构的特点提出接触碰撞动力学模型,此模型包括等效弹簧阻尼模型,ADAMS中的接触力模型以及摩擦力模型。接着在充分分析并联机构结构特点的基础上,以等效弹簧阻尼模型和ADAMS中的接触力模型为基础,分析了不同材料运动副间隙机构的动力学性能；最后利用动力学理论和ADAMS仿真工具分析铰链间隙和构件柔性对3-RRRT三自由度并联机构动力学性能的影响,并得到不同驱动速度情况下,间隙和柔性对该机构动力学性能的影响。研究结果表明：①间隙越大,接触频率越快,振幅越大,机构运动受到的影响也越大。但是无论间隙有多大,接触情况都是由剧烈振动到平稳状态过渡,并且间隙的存在对动平台的速度影响很小。②机构中存在间隙的铰链越多,机构受到的接触力越大,冲击越大,机构的运动越容易受到影响。③柔性对并联机构的速度和加速度都有影响,并且随着间隙的增大柔性的影响也越大,但柔性对接触力的影响不是很大。④驱动速度越快,间隙和柔性对机构动力学性能的影响越大,并且运动越不平稳。
[Abstract]:The errors in the manufacturing and installation of the parallel mechanism and the wear and tear in the long-term motion process will cause the gap in the link part of the mechanism itself. At the same time, the rod part in the parallel mechanism is a slender rod, which will make a large deflection motion. It is necessary to regard it as a flexible rod. Hinge clearance and member flexibility will affect the dynamic performance of the parallel mechanism, which will cause vibration and noise during the operation of the machine, aggravate the wear, and reduce the working efficiency and output accuracy. In severe cases, the mechanism will not function properly. Therefore, the influence of hinge clearance and rod flexibility should be taken into account when analyzing the dynamic performance of parallel mechanism. In this paper, the research background and development status of multi-body system dynamics of three-degree-of-freedom parallel mechanism with clearance and flexibility are systematically reviewed, and the main contents of this research are put forward by analyzing the problems in the existing research. Secondly, on the basis of introducing the dynamic analysis method of the clearance mechanism systematically, according to the characteristics of the parallel mechanism, the contact impact dynamic model is proposed. The model includes the contact force model and the friction force model in the equivalent spring damping model Adams. Based on the analysis of the structural characteristics of the parallel mechanism and the equivalent spring damping model and the contact force model in ADAMS, the dynamic performance of the clearance mechanism with different materials is analyzed. Finally, the effects of hinge clearance and component flexibility on the dynamic performance of 3-RRRT three-degree-of-freedom parallel mechanism are analyzed by using dynamic theory and ADAMS simulation tool, and the effects of clearance and flexibility on the dynamic performance of 3-RRRT three-DOF parallel mechanism are obtained under different driving speeds. The results show that the larger the gap is, the faster the contact frequency is and the larger the amplitude is, and the greater the movement of the mechanism is. However, no matter how big the gap is, the contact condition is transition from violent vibration to steady state, and the existence of clearance has a small influence on the velocity of moving platform. 2. The more joints with clearance, the greater the contact force of the mechanism is. The greater the impact, the more vulnerable the motion of the mechanism is to the influence of flexibility on the speed and acceleration of the parallel mechanism, and the greater the effect of the flexibility with the increase of the clearance. However, the effect of flexibility on the contact force is not great. The faster the driving speed is, the greater the influence of clearance and flexibility on the dynamic performance of the mechanism is, and the more unsteady the motion is.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH112

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