Non-singular Terminal Sliding Mode Control (NTSMC) for Piezoelectric Fast Tool Servo (FTS)

抄録

Recently, due to rapid development of the photoelectric industry, the needs for non-axisymmetric aspheric optical components are increasingly presented, such as the lenses for short imagine distances head-up display and compensation lens for elliptical laser beam. The machining process for such die/mold requires an external feeding device mounted to a machine tool to achieve fast tool servo (FTS) function for fabricating a non-axisymmetric surface. In this speech, the non-singular terminal sliding mode controller (NTSMC) is introduced to precisely control the feeding device consisted of a piezoelectric (PZT) actuator. To examine the control performance based on the NTSMC, a machining example of non-axisymmetric aspheric surface is provided, details of controller design are described, and both the simulation work and control practice are presented. As the results of performance examinations, the peak-to-valley (PV) tracking errors of simulation and control practice are 0.01 nm and 0.96 μm, respectively. This large difference is found mainly due to a slow sampling rate of position commands. Finally, the effect of machining experiment based on the NTSMC is demonstrated. Future work to enhance machining performance through hardware improvement is discussed.