Analysis and design of voice-coil actuator used in fast tool servo

Free-Form optics have complicated surfaces and the fast tool servo (FTS) is a highly effective method to fabricate such parts. With regard to the fact that the piezoelectric FTS actuator has limited fabricating capacity as of its low stroke, a long stroke FTS project driven with voice coil actuator (VCA) was presented. Compared with piezoelectric actuator, the VCA can fabricate broader range of parts owing to its longer stroke. Illustrated with a typical optical freeform part, the key performance parameters of FTS are analyzed. The structure of VCA was given, the theoretical model of VCA was built, the closed-loop controller was designed and the actual performance of VCA actuator was tested. The test results indicate that the designed VCA actuator has long stroke and high frequency response, and the frequency response can reach 300 Hz when at stroke of 200 μm, More important, at this level of stoke, the frequency response presented is better than similar products abroad.