四自由度并联工作台静动态特性分析
发布时间：2018-11-21 15:03
【摘要】：本文所研究的新型并联工作台在空间内有两个移动自由度及两个转动自由度，，可以与铣、镗、加工中心等机床组合使用，能够完成对零空间件任意角度平面及孔的加工要求。本文对该并联工作台的自由度分析、运动学、静力学及静动态特性等进行了研究和探讨。 本文首先介绍了并联机构的国内外研究现状，叙述了本文所要研究的并联工作台的设计目的。接着，采用螺旋理论分析四自由度并联工作台的自由度的数目及性质。然后，对并联工作台进行了位置分析，利用解析法给出该并联工作台的位置反解，采用数值方法中的牛顿下山法求取了该并联工作台的位置正解，并利用反解验证了正解的正确性。利用求导法和螺旋法分别求取了并联工作台的速度雅可比矩阵，得到了并联工作台各支链输入速度与动平台输出速度之间的关系，且进行了奇异性分析。研究了该并联工作台的静力学。利用雅可比矩阵，运用虚功原理求得了动平台所受外力和外力矩到驱动关节的运动关系。并通过雅可比矩阵方便的求得了并联工作台的刚度矩阵。对并联工作台有限元模型的建立过程进行了研究，选取了并联工作台的5种极限位姿，建立了精确有限元模型。在有限元模型的基础上，对并联工作台进行了静力特性分析，考察了在工作载荷下，并联工作台在五种极限位姿处的应力和变形特点。运用有限元软件动态特性分析功能，对并联工作台进行了模态分析，根据分析结果，找出工作台的薄弱环节，并总结并联工作台的动态特性。对一般钻孔空过程中由钻削力引起的谐响应进行研究，找出了在钻孔过程中应避开的频率范围。 对于机构自由度的分析，传统上采用CGK公式计算其自由度数目，而自由度性质只能靠研究者的经验判断。本文采用螺旋理论分析该并联工作台的自由度，不仅计算了其自由度的数目，而且准确给出了自由度的性质。由于并联工作台动平台可以运动，不同位姿其静动态特性不同，为了研究工作台的静动特性，故选取了工作台的5个极限位姿，分别分析并联工作台在5种极限位姿下的静动特性，找出了工作台的薄弱环节以及并联工作台在钻孔时应该避开的频率范围。
[Abstract]:The new parallel worktable studied in this paper has two degrees of freedom of movement and two degrees of freedom of rotation in space, which can be used in combination with milling, boring, machining center and other machine tools, and can fulfill the machining requirements of any angle plane and hole of zero space parts. In this paper, the degree of freedom analysis, kinematics, statics and static and dynamic characteristics of the parallel table are studied and discussed. This paper first introduces the research status of parallel mechanism at home and abroad, and describes the design purpose of the parallel table to be studied in this paper. Then, the helical theory is used to analyze the number and properties of the four-DOF parallel worktable. Then, the position of the parallel table is analyzed, the inverse solution of the parallel table is given by using the analytic method, and the positive solution of the position of the parallel table is obtained by Newton's downhill method in the numerical method. The correctness of the positive solution is verified by the inverse solution. The velocity Jacobian matrix of the parallel table is obtained by using the derivation method and the spiral method. The relationship between the input speed of each branch chain and the output velocity of the moving platform is obtained, and the singularity analysis is carried out. The statics of the parallel table is studied. By using Jacobian matrix and the principle of virtual work, the motion relationship between the driving joint and the external force and moment of the moving platform is obtained. The stiffness matrix of parallel table is obtained conveniently by Jacobian matrix. The process of establishing the finite element model of parallel worktable is studied. Five kinds of limit positions of parallel worktable are selected and the accurate finite element model is established. Based on the finite element model, the static characteristics of the parallel table are analyzed, and the stress and deformation characteristics of the parallel table at five kinds of extreme positions are investigated under the working load. The modal analysis of the parallel worktable is carried out by using the dynamic characteristic analysis function of the finite element software. According to the analysis results, the weak links of the worktable are found out, and the dynamic characteristics of the parallel worktable are summarized. The harmonic response caused by drilling force in the general borehole process is studied and the frequency range that should be avoided in the drilling process is found out. For the analysis of the degree of freedom of the mechanism, the number of degrees of freedom is traditionally calculated by the CGK formula, and the nature of the degree of freedom can only be judged by the experience of the researcher. In this paper, the degree of freedom of the parallel table is analyzed by spiral theory. Not only the number of degrees of freedom is calculated, but also the property of the degree of freedom is given accurately. In order to study the static and dynamic characteristics of the parallel worktable, five limit positions are selected for studying the static and dynamic characteristics of the parallel worktable, because the moving platform of the parallel worktable can move and the static and dynamic characteristics of the platform are different from each other. The static and dynamic characteristics of the parallel table under five kinds of extreme positions are analyzed respectively. The weak links of the parallel table and the frequency range of the parallel table should be avoided when drilling holes are found out.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH113
本文编号：2347325
[Abstract]:The new parallel worktable studied in this paper has two degrees of freedom of movement and two degrees of freedom of rotation in space, which can be used in combination with milling, boring, machining center and other machine tools, and can fulfill the machining requirements of any angle plane and hole of zero space parts. In this paper, the degree of freedom analysis, kinematics, statics and static and dynamic characteristics of the parallel table are studied and discussed. This paper first introduces the research status of parallel mechanism at home and abroad, and describes the design purpose of the parallel table to be studied in this paper. Then, the helical theory is used to analyze the number and properties of the four-DOF parallel worktable. Then, the position of the parallel table is analyzed, the inverse solution of the parallel table is given by using the analytic method, and the positive solution of the position of the parallel table is obtained by Newton's downhill method in the numerical method. The correctness of the positive solution is verified by the inverse solution. The velocity Jacobian matrix of the parallel table is obtained by using the derivation method and the spiral method. The relationship between the input speed of each branch chain and the output velocity of the moving platform is obtained, and the singularity analysis is carried out. The statics of the parallel table is studied. By using Jacobian matrix and the principle of virtual work, the motion relationship between the driving joint and the external force and moment of the moving platform is obtained. The stiffness matrix of parallel table is obtained conveniently by Jacobian matrix. The process of establishing the finite element model of parallel worktable is studied. Five kinds of limit positions of parallel worktable are selected and the accurate finite element model is established. Based on the finite element model, the static characteristics of the parallel table are analyzed, and the stress and deformation characteristics of the parallel table at five kinds of extreme positions are investigated under the working load. The modal analysis of the parallel worktable is carried out by using the dynamic characteristic analysis function of the finite element software. According to the analysis results, the weak links of the worktable are found out, and the dynamic characteristics of the parallel worktable are summarized. The harmonic response caused by drilling force in the general borehole process is studied and the frequency range that should be avoided in the drilling process is found out. For the analysis of the degree of freedom of the mechanism, the number of degrees of freedom is traditionally calculated by the CGK formula, and the nature of the degree of freedom can only be judged by the experience of the researcher. In this paper, the degree of freedom of the parallel table is analyzed by spiral theory. Not only the number of degrees of freedom is calculated, but also the property of the degree of freedom is given accurately. In order to study the static and dynamic characteristics of the parallel worktable, five limit positions are selected for studying the static and dynamic characteristics of the parallel worktable, because the moving platform of the parallel worktable can move and the static and dynamic characteristics of the platform are different from each other. The static and dynamic characteristics of the parallel table under five kinds of extreme positions are analyzed respectively. The weak links of the parallel table and the frequency range of the parallel table should be avoided when drilling holes are found out.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH113
【引证文献】
相关硕士学位论文 前1条
1 彭礼斌;2-PRS/2-UPS四自由度并联工作台工作精度研究[D];兰州理工大学;2013年
本文编号：2347325
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