A decoupled five-axis local smoothing interpolation method to achieve continuous acceleration of tool axis

Five-axis machines are widely used in high-speed and high-precision machining of complex sculptured surfaces for the ability to adjust the tool orientation. But, most of the five-axis machining trajectories generated by computer-aided manufacturing (CAM) software are G01 blocks in the form of a large number of linear segments. The G01 blocks for surface machining show inadequacies as their high-order discontinuities. Although there are a lot of researches to deal with the discontinuities, there are still many problems such as smoothing error control, motion synchronization, kinematic constraints limitation. Besides, the kinematic constraints of the tool orientation motion are always neglected. In this paper, a two-step real-time decoupling local smoothing method is proposed for the problem of the five-axis tool path smoothing. The C2 continuity of the tool path is guaranteed within the error limited. Not only the kinematic constraints of tool tip motion but also the kinematic constraints of the tool orientation motion are considered. The continuous acceleration of each axis motion of the machine tool is realized through feed-rate scheduling by finite impulse response (FIR) filtering. Finally, through numerical simulations and experiments, compared with the existing method and G01 linear interpolation, it is verified that the proposed smoothing interpolation method has a higher computation efficiency and can improve the processing efficiency and surface quality of the tool path while satisfying the specified smoothing error constraints and kinematic constraints.