Weighted sum of vector norms based contouring control method for five-axis CNC machine tools

Abstract

Component-based contouring error control is a typical contouring control method for five-axis CNC machine tools. However, the existing studies based on this method still have two problems: (1) the contouring errors may increase in some regions rather than a reduction; (2) the reduction of contouring errors in other regions is limited. In this paper, first, the reasons for the above mentioned two problems are analyzed: (1) the inconsistency in the coordinate systems of tracking errors and contouring error components leads to an undesirable increase of the contouring errors; (2) the cancellation of tracking errors and contouring error components results in a limited reduction of the contouring errors. Then, by considering the weighted sum of two vector norms, which are composed of tracking errors and contouring error components in the same workpiece coordinate system, respectively, a novel control strategy is proposed. Experiments are conducted on a tilting-rotary-table (TRT) type five-axis CNC machine tool. Compared with the case without contouring error control action, the results demonstrate that the proposed control strategy can reduce the tool position and tool orientation contouring errors by 85.4% and 87.78%, respectively, in a global way.