【作者】 莫建清；

【导师】 黄茂林；

【作者基本信息】 重庆大学 ， 机械设计及理论， 2004， 硕士

【摘要】 自调机构主要是基于平面闭链机构中广泛存在的过约束而提出的,它研究的对象是机构本身。由于过约束的存在,造成机构对制造、安装误差特别是运动副元素的形位误差十分敏感,同时由于不可避免的内部和外部不确定因素的影响,常会造成机构运动的“障碍”及系统中某些构件的变形和运动副中的附加动载荷,使其动力特性较差,如不通过设计加以解决,则难以满足高效率、高稳定性的要求。因此,研究运动副形位误差对平面闭链机构的动力学性能的影响程度,为机构的误差控制和精度设计提供了基础。自适应机构是一类特殊而又广泛应用的机构,目前主要指的是内力加压装置。这类机械装置允许其工作对象的尺寸、位置在一定的范围内变化,它适应的对象主要是指外部对象。对于自适应机构的本身,过约束的消极影响仍然存在。因此,研究这类自适应机构的创新设计方案及其自调结构的设计的有效方法和途径,对于提高机构的性能和工作稳定性,都具有积极的意义。本文对自适应机构的创新设计及其自调结构的设计、运动副误差对平面连杆机构的动力学性能的影响程度进行了深入、系统的研究。首次对“自适应机构”作出了定义,并且总结出了自适应机构分析综合的一般方法。以自由度为-1的8杆链为基础,首次提出了自适应机构的自调结构的设计及其优选方法。以结构力学中处理静不定结构的受力分析方法为基础,通过分析机构的变形协调条件,并根据拆副处的实际铰链轴线相对理论正确的铰链轴线的位移量以及方位角的变化量,提出了存在运动副误差的平面连杆机构的动力学单因素定量分析方法,建立了机构中不同运动副、不同运动副元素在不同平面内存在误差时机构的动力学方程,从而为机构的结构设计及其精度设计提供了理论依据。最后应用ADAMS软件,建立了运动副误差对机构性能影响的动态仿真模型,分别从定性和定量的角度说明了运动副误差对机构动力学性能的影响程度。本文的工作,丰富了机构结构设计理论,提出了自适应机构的创新综合方法,进一步推进了平面约束不确定性的影响分析及自调结构的分析、设计理论与方法的研究。更多还原

【Abstract】 Compared with self-adaptive mechanism, what self-adjusting mechanism studies is the mechanism with overconstraint itself. Because of overconstraint, it is very sensitive to the fabrication error,assembly error and angular error from the axis of kinematic pairs. And the unavoidable inner or outer uncertain factors lead to kinematic obstacle,deformation of components and additional dynamic load of kinematic pairs, which makes its dynamatics performance relatively bad. Therefore, if this problem does not to be solved, it is difficult to meet the request of high stability and high efficiency. Self-adaptive mechanism, which are mainly internal force exerting devices at present, is special and used extensively. This kind of mechanical device allows its workpiece’s size and position varied in certain range, and what they study are external object. So, to themselves, the negative influence of overconstraint still exist. Therefore, it is meaningful for improving the performance of mechanism and working stability to study the innovative design of adaptive mechanism and their effective design of self-adjusting structure.In this paper, the innovation design of self-adaptive mechanism, design of self-adjusting structure and the influence degree of the dynamics performance causing by angular error from the axis of kinematic pairs have been carried out systematically. " Self-adaptive mechanism " was definited for the first time, and the general analysis and synthesis method of self-adaptive mechanism was summarized. The design method and optimum synthesis method of self-adjusting structure about this mechanism were present for the first time.Dynamics equations with different angular error were set up based on the force analysis method of statically indeterminate structure, and based on the introduction of comaltibility condition of twisting and bending deformation of link. An analysis method for the dynamics of planar linkage with kinematic-pair-axis errors was presented, which offered the theoretical foundation for the structural design and precision design of mechanism.Finally, to demonstrate the degree of influence of dynamics performance causing by angular error from the axis of kinematic pairs, a dynamic emulation model was set up by using ADAMS software .更多还原