RTCP test axis motion planning for five-axis machine tool dynamic performance using observability optimization based on modified genetic algorithm

In the five-axis CNC machining process, the dynamic tracking error due to servo dynamic performance deficiency is a main cause of processing inaccuracy during precise high-speed machining. The rotation tool center point (RTCP) test is commonly used to measure the dynamic performance of five-axis machine tools. The key to the capability of the RTCP test is axis motion planning in the test process. However, the axis motion plans for RTCP tests are usually based on simple motion instruction or engineering experience; the mechanism of the discrepancy between different axis motion plans is unclear. In this study, the axis motion planning process for RTCP dynamic performance tests is analyzed, and a novel axis motion planning method is proposed. The axis motion planning process is directly connected to the mechanism of dynamic tracking error; error observability is used as the index to guide RTCP axis motion planning. A modified genetic algorithm is used to select the sensitive rotary axis position and velocity combos; cubic spline interpolation is used to plan the axis motions based on the sensitive position and velocity combos.