| Five-axis CNC machine tools are more widely used in the processing of complexworkpieces, but the complexity of writing NC program for workpieces has become animportant factor affecting the efficiency of CNC programmers. By studying theconversion relationship between the Cartesian coordinate system, we find it’s simple touse framework to describe the coordinate transformation between Cartesian coordinates.Under the concept of framework, the Special framework and the kinematictransformation become the focus of research. The Special framework refers to thecoordinate transformation between the special coordinate system and the workpiececoordinate system. In order to meet the diverse needs of users to define specialcoordinate system, we list five definition methods give the approximate realizationideas for each method. Kinematic transformation refers to the coordinate transformationbetween the Machine Coordinate System and the Basic coordinate system. Analysisingthe motion feature of three categories of five-axis CNC machine tool, combined withthe principles of kinematics, we establish three different kinematic models. We get ageneral rotational model for five-axis machine rotational kinematics models. For therotation matrix is an orthogonal matrix, we can solve the equation with GaussianElimination after a property transformation. There is also a strategy to find the bestsolution when the equation has multiple solutions. With the best solution, we can solvethe translational motion model equations through appropriate matrix transformation.Finally，the correctness of the algorithm are confirmed by the VERICUT simulation.With the experience of different data scale, we verify the efficiency of the kinematicmodel.Using the framework to deal with the tool path file directly, so that the coordinatescan be easily switched between the machine coordinate system and programmingcoordinate system, so five-axis motion control becomes more convenient. |
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