Research And Development On 7-Axis Parallel Machine Tool NC System

At present, the complex and irregular surface parts such as leaves and impellers are mainly machined by imported 5-axis NC centers. With its multi-freedom unique advantage, a new machine tool -- parallel CNC machine tool joins the processing queue of complex, irregular surface parts, and provides new vitality to the development of manufacturing industry. Now that 5-axis machining centers are indispensable and the imported price is expensive, the development of homemade parallel CNC machine tools are of high practicability and wide market prospects.The dissertation focuses on the following aspects:Taking BXK-4027 7-axes parallel NC machine tools made in Harbin Measuring & Cutting Tool Group Co. Ltd. for reference, the parallel machine tool structure, functions requirements and control methods are analyzed and HuangZhong Century Star NC system is chosen as the development platform.After the static and dynamic platform space structure and posture are analyzed, the forward and inverse algorithms of parallel machine tool (PTM) are studied. Because the forward algorithm is more difficult in kinematics, so the iteration of Newton—Raphson method is especially developed to solve the problem, which is very practical.Based on the analysis of parts processing, the parallel machine Controller is developed, which includes two main parts, the interpreter and PLC. The interpreter is mainly for decoding process, the decomposition of rotate table, code conversion, virtual axis rough interpolation, speed control, real axis fine interpolation and handling of position control etc. PLC control mainly controls the real axes, MST auxiliary functions and each virtual axis motions under non-automated control status.The parallel NC simulation realization for the two-dimensional and three-dimensional simulation and the track simulation is also realized, which makes the processing more intuitive and embodied.Based on Huazhong Century Star NC system, the functions of parallel NC system are researched and realized, and the parallel machine NC system is developed.