Research On Comprehensive Error Compensation System Of Five-Axis CNC Machine Tool’s Rotary Axes

With the continuous development of equipment manufacturing industry, five-axis CNC machine tool plays a more and more important role. However, because of the complexity of structure and control, the machining precision is seriously affected. Five-axis CNC machine tool includes linear and rotary axes, for the measurement and compensation of errors linked to liear axes, there are relatively mature theories and methods, so this dissertation focuses on modeling, measurement and compensation method of geometric errors related to rotary axes of five-axis CNC machine tool which are considerably affect the machining precision, and verifies the theories and methods by the actual experiments.In this dissertation, according to the kinematic chains of five-axis CNC machine tool, the error comprehensive model can be obtained by homogeneous coordinate transformation matrix. An improved measurement method of static errors is presented based on the existing one, and the installation error is introduced into the error model. Then the relationship between the length variation of DBB and the existing static errors can be obtained, accoding to this, the identification algorithm of static errors is deduced. This dissertation takes the influence of static errors on the measurement of motional errors into consideration and adopts the method in which the influence of static errors on the length variation of DBB is eliminated from the measured data while performing the measurement of motional errors and then use the processed data to identify the motional errors. Similar to the analysis of the measurement of static errors, the relationship between the length variation of DBB and the existing motional errors can be obtained, accoding to this, the identification algorithm of motional errors is deduced.A new compensation strategy based on the error model is presented, the ideal tool position and vector can be obtained by the ideal kinematic forward solution and introduced into the kinematics backward solution with error, and then the modified G code can be calculated and used to machine the work-piece.Based on the theoretical analysis and simulation experiments, the dissertation verify the effectiveness of the proposed modeling, measurement and compensation. A method of virtual machining the circular cross section of the cone-frustum is performed to confirm the validity or effectiveness of the proposed strategy.