Dynamic performance test under complicated motion states for five-axis machine tools based on double ballbar

During five-axis CNC machining, the dynamic tracking error caused by imperfect servo dynamic performance is becoming the major factor affecting the accuracy during high-speed and high-precision manufacturing. The double ballbar (DBB) test is one of the commonly used dynamic performance tests, but existing DBB test methods do not have satisfactory test capability for the requirement of complex freeform surface machining. In this paper, on the basis of summarized of dynamic tracking error's mechanism and characteristics, an improved dynamic performance test based on DBB, which is named the circle-8 test, is proposed. In this test, a provenly efficient RTCP test trajectory is used to rebuild the DBB test process, which includes complex movements of all the five motion axes. To exhibit the improvement of the circle-8 test, this test and the BK3 test of ISO standard, which is considered as a comparison, are conducted in a five-axis machine tool with a tilting rotary table. According to the simulation and experiment results, for common dynamic inaccuracy situations, the circle-8 test always has better sensitivity of dynamic performance test than BK3 test. The above-improved dynamic performance test can be applied to provide effective data for the research of modeling and error reduction of five-axis machine tools.