一种空间三平移并联机构的运动学性能与仿真研究

发布时间：2018-06-28 22:30

本文选题：并联机构 + 3-PRC　；参考：《中北大学》2017年硕士论文

【摘要】：三自由度并联机构是并联机构学中的重要分支之一,与六自由度并联机构相比,该类并联机构有运动支链少、承载能力高以及较易控制等优点,在微电子、高精度加工中以及医疗器械等领域得到广泛应用。本文以空间3-PRC三平移并联机构为研究对象,主要对3-PRC并联机构进行运动学、动力学以及虚拟样机的仿真研究。首先,基于旋量理论,分析了3-PRC并联机构的自由度,验证了其动平台的输出运动为三维平移运动;根据3-PRC并联机构的几何约束关系建立了位置正解和位置反解方程,数值验证了位置正解、反解的正确性;在位置解的基础上,用运动影响系数法对速度和加速度的变化规律进行了分析;运用Jacobian代数法对奇异性进行了分析,得出了出现正向奇异和反向奇异时杆件间的位置关系。第二,基于位置反解及几何约束条件,用数值搜索法编程出3-PRC并联机构的工作空间,用MATLAB软件中SimMechanics模块进行了运动仿真,以验证了工作空间求解的正确性;最后分析了驱动滑移杆与静平台的夹角对工作空间的影响。第三,用凯恩方程法建立了质点系和刚体的凯恩方程,动力学建模求得了该机构各杆件的广义速度与偏速度,构建出了3-PRC并联机构的动力学凯恩方程。第四,用三维建模Pro/E软件和ADAMS软件创建了3-PRC并联机构的虚拟样机模型,对其进行了运动学仿真,在ADAMS后处理模块中测得了动平台末端参考点的位移、速度及加速度变化曲线图;对3-PRC并联机构进行了动力学仿真,得出了消耗功率和驱动力的变化规律,为电机的选型提供理论指导。最后,用Pro/E软件与ANSYS Workbench软件,对3-PRC并联机构进行了有限元分析,确定了动平台处于两种位姿时机构中变形和所受应力最大部位,找到了整体结构中的薄弱地方。
[Abstract]:Three-DOF parallel mechanism is one of the important branches of parallel mechanism. Compared with 6-DOF parallel mechanism, this kind of parallel mechanism has the advantages of less kinematic branching chain, higher load-carrying capacity and easier control. High-precision machining and medical devices and other fields have been widely used. In this paper, the 3-PRC three-translational parallel mechanism is taken as the research object, and the kinematics, dynamics and virtual prototype of the 3-PRC parallel mechanism are studied. Firstly, based on the spinor theory, the degree of freedom of 3-PRC parallel mechanism is analyzed, which verifies that the output motion of the moving platform is a three-dimensional translational motion, and the forward and inverse position equations are established according to the geometric constraints of the 3-PRC parallel mechanism. Numerical results show that the positive and inverse solutions are correct. On the basis of the position solutions, the law of velocity and acceleration is analyzed by the method of motion influence coefficient, and the singularity is analyzed by Jacobian algebraic method. The position relationship between the bars with positive singularity and reverse singularity is obtained. Secondly, based on the position inverse solution and geometric constraints, the workspace of 3-PRC parallel mechanism is programmed by numerical search method, and the kinematic simulation is carried out with SimMechanics module in MATLAB software to verify the correctness of the workspace solution. Finally, the influence of the angle between the driving slip rod and the static platform on the workspace is analyzed. Thirdly, the Kane equations of particle system and rigid body are established by using the Kane equation method. The generalized velocity and partial velocity of each member of the mechanism are obtained by dynamic modeling, and the dynamic Kane equation of 3-PRC parallel mechanism is constructed. Fourthly, the virtual prototype model of 3-PRC parallel mechanism is created by using the software Prop / E and Adams, and the kinematics simulation is carried out. The displacement, velocity and acceleration curves of the reference point at the end of the moving platform are measured in the Adams post-processing module. The dynamic simulation of 3-PRC parallel mechanism is carried out, and the variation law of power consumption and driving force is obtained, which provides theoretical guidance for motor selection. Finally, using Pro-E software and ANSYS Workbench software, the finite element analysis of 3-PRC parallel mechanism is carried out, the maximum deformation and stress of the mechanism are determined when the moving platform is in two positions, and the weak place in the whole structure is found.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH112

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