A series-parallel machine tool and its error analysis Zhao Junwei Xu Zhengao Fanguang and other kinds of series-parallel machine tools and their error analysis Zhao Junwei Xu Zhengao Fan Illumination Li Zhuzheng Miscellaneous oil shot manufacturing mistakes and the sliding of the carriage to the tomb to the tool space movement Position ejaculation in order to adapt to speed accuracy requirements Several beds in the manufacturing industry are developing parallel machine tools as a new generation of processing equipment Parallel machine tools The main advantage is that all the connecting rods are force members, so there are many rigid and low inertia components Closed loop is beneficial to the offset of assembly error. 2 The current degree of freedom parallel machine port 01 is also difficult to develop. The volume ratio of the working space to the machine tool is too small. 3,4 The hinge head of the hinge and the ball joint are low in rigidity and high in cost. If the rod is too high in the vicinity of the singular point 85, such as 0, the desired structural rigidity and machining accuracy are often not available. Moreover, if the existing general structure and control unit are abandoned, the machine tool will undoubtedly be added. Developed into a combination of wood and Zhoumu, and the development of a series of parallel-type machine tools by the Taiwan Industry Research Institute, with its unique structural features, many at home and abroad. The literature discusses the motion and control of parallel actuators, most of which focus on the analysis of the kinematics of parallel mechanisms and the numerical solution and the dynamic accuracy analysis.7 There is little discussion about the spatial error modeling method involving parallel-structured machine tools. This paper describes the analysis of the motion error of the axis of the bamboo, and the main error sources. The space motion accuracy of the spindle platform. The structure of the parallel structure of the machine is mainly composed of a degree of freedom spindle platform and a traditional The two-degree-of-freedom 17 workbench is composed of the workpiece to be clamped on the workbench to obtain the dimensional plane motion main shaft installed in the center of the platform, and the main shaft platform is respectively connected with the three connecting rods through three circumferentially distributed hinge joints. The other ends of each of the links are respectively connected to the respective slides by cylindrical hinges. The slides can be moved vertically along the guide rails of the respective columns. The three columns are uniformly distributed in series and parallel structure compared with the 4-parallel structure. The wind has large working space control, which simplifies the ease of manufacturing parts and components. For the synthetic analysis of machine tool movement, three coordinate systems are established respectively. 2 fixed coordinate system 72 is established on the pedestal; motion coordinate system is inserted, and the heart of the 17 workbench is set up; 7 placed on the tip or the shaft end of the shaft. = The shaft coincides with the spindle axis and the ball joint 6 is located in the 107 plane. The standard system. 2 relative coordinates 糸 272 orientation 4 mountain column homogeneous transformation matrix 7 to describe the fund project cross-strait cooperation research project 0883517, respectively, the coordinate axis is less and 2 relative to the coordinate system; 2 direction single, 2, 31 and respectively The direction of the spindle platform relative to the coordinate axis is 7 and. The spatial position of each ball joint on the main shaft platform in the coordinate system 172 is determined by the cylindrical hinge, and each connecting rod is only outside, so the position error of the center of the ball joint must be the if the connecting rod is the rigid member unit. Then, the projection of 0 on the name is equal to the sum of the projection on the top, that is, the kidney error 2 of the ball hinge is caused by the position error and the link degree error of the round hinge in the same branch, so F3=1 It is a motion within 2, so the following equation can be derived from the distance from the center of the platform. And the factory is a function of the direction angle, that is, they depend on the motion posture of the stage, 3 error analysis and modeling due to manufacturing assembly error left control and actuation set elastic deformation 4 thermal deformation and other flashing deposits. Inevitably causing the inaccuracy of the tool space motion relative to the fixed coordinate system tool nose coordinate system 2 The position error vector of the origin and the direction error vector of the platform can be defined as the position error of the cylindrical hinge mainly caused by the carriage feed error vector; The boundary is the link length error. Substituting Equation 6 into Equation 7 or into a matrix form 3.2 constraint condition, the constraint equation can be derived. If the direction unit vector 2 of the cylinder hinge axis is based on the unit vector of the link and the orthogonal condition, the above formula is Matrix form serialization 8 and 9 can be used to obtain a series-parallel machine tool and its error analysis. Zhao Junwei Xu Zhengao Fan et al. The machine tool structure can be decomposed into three parallel structural rings. Each structural ring can form a closed vector chain 4. The space vector of each foot in the vector chain is the cylindrical hinge center to the ball hinge center. Space vector, the position vector of the workbench for the 7th; the space vector from the center of the workbench to the tip of the tool is the space vector from the tip of the tool to the center of the ball joint; A transformation matrix relative to coordinate system 0. The difference between the two sides of the discussion type 12 is based on the same constraint conditions. According to the same constraint conditions, the simultaneous equations 9 and 13 are sorted out or can be seen by the formula 14. When the error term is not considered, and the operation, ie, you =, The form is exactly the same as that of Equation 10, which also verifies the correctness of the error model. 4 The calculation parameter based on the calculation example is calculated. The length error of the rod is 1 net, 6, and the accuracy level is 6 In the calculation example, the spindle platform is called the mold of the three carriage feed errors with respect to the coordinate system. When 1=2,3 is the same, the influence of Qing on the space position of the tool tip and the attitude of the platform; 6 is the effect of 1 on the space movement position of the tool tip and the direction of the platform. The old theory can also be analyzed separately and the influence can be seen from 5. If the feed error of the three slides is the same as the length error of the rod length, the error of the length of the tool is 3, and the error of the pitch of the coffee platform is only considered when the error of the rod 1 is present, and the positioning accuracy of the tool tip in the vertical direction is 6 The influence of 5 is large, due to the symmetry of the machine tool structure, at this time, the other spatial error items are less affected and less affected; 6 it is clear that if there is an error in a certain component or structural branch, the spatial positioning accuracy of the tool and the platform The attitude has a significant influence on the length error of the pole 5, the error of the tool tip position error is the wrong direction of the platform of the MM platform, and the conclusion is that the structure of the structure 1 is a general-purpose series structure single 兀, which overcomes the existing processing space of the parallel machine tool. The shortcomings of control difficulties, through the error analysis of the series-parallel machine tool, the derived error model is conducive to the progress of the analysis of the impact of various error sources on the accuracy of machine tool motion, the source of the error source in the branch of the m structure Published paper 31 Xu Zhengao, male, born in 1955, Huazhong University of Science and Technology, School of Mechanical Science and Engineering, arrived in Fan Guang, male, born in 1950, Taiwan University of Mechanical Engineering, Department of Mechanical Engineering, Li Zhu, male, born in 1934. Professor of the Department of Mechanical Science and Engineering, Huazhong University of Science and Technology, Ph.D. (Finish) Oilfield Accessories,Drill Bit,Drill Pipe,Steel Casing Pipe PUYANG RENHE INDUSTRY CO.,LTD , https://www.rhsuckerrod.com