Study On A Novel Type 5-DOF Series-Parallel Machine Tool And Its NC Architecture

The academia has always paid attention to the parallel kinematics machine tool (PKM) ever since it came out in 1990s, because the PKM has unique advantages compared to traditional machine tool, such as high rigidity in theory, high bearing capacity, light weight, high speed of response, symmetry structure, high compensation capacity, high degree of modularization, high restructuring capacity, high addtns of technology and so on. And the application field of machine tools is enlarged by the coming out of PKM. But the available workspace of PKM is always very small, which is a common problem existing in PKM. Meanwhile, the PKM with multi-DOF is always with high degree of couple and complex NC system, and it's hard to build up the move modeling. In order to make full use of the advantages of series machine tool and PKM and conquer the disadvantages of them, a novel type series-parallel machine tool with 5-DOF is proposed in this paper. The main structure of the series-parallel machine tool is a parallel mechanism with 3-HSS structure, and the series mechanism of the series-parallel machine tool, which is a turning mechanism with 2-DOF, is installed on the mobile platform of the parallel mechanism. The three ballscrews of the parallel mechanism were set horizontally and the move ability of the parallel mechanism is better in horizon. So the available workspace of the series-parallel machine tool is larger. A deep and system research is done in this paper aiming at the key technology of the structure and NC architecture of the series-parallel machine tool. The main works are as follows.The DOF analysis of the parallel mechanism of this series-parallel machine tool is done by using the structure theory of parallel mechanism. The kinematics analysis of the series-parallel machine tool is done aiming at the structure traits, the direct kinematics and inverse kinematics are solved and the mathematical modeling of NC architecture is built. The prototype of the series-parallel machine tool with 5-DOF proposed in this paper has been manufactured based on the kinematics analysis.Based on the open, modular and integrated architecture, the NC architecture of series-parallel machine tool is built up. The "IPC+PMAC" model is adopted in this paper to build up the hardware platform, In this model the system software and data processing ability of IPC can be completely applied in the NC architecture. Meanwhile, the real-time controlling function of PMAC can also be fully used.The software platform of the NC architecture is designed based on the open integrated NC architecture. The basis of the software of the integrated open NC architecture is the Windows platform and the programmable language is Visual C++. Based on the open and modularized design idea, the control software and system management software are designed. So, this software platform is with good open ability and good extendibility.According to the structure traits of the series-parallel machine tool with 5-DOF, the interpolation functions of spacial line and spacial circle, coordinate transformation function and kinematic transformation function are developed in this paper. According to the functions of PMAC, some other functions of the NC architecture are developed too, such as motor test function, speed setting function, file download function and so on.The correct control method and model have been achieved through the on-line manufacturing experiments, which verify the reasonableness of the structure and the correctness oftheNC platform.