Three-degree-of-freedom large-stroke fast tool servo device and curved surface machining method thereof

The invention discloses a three-degree-of-freedom large-stroke fast tool servo device which comprises a working rack, a voice coil motor, a Z-direction displacement transmission mechanism, a three-axis connecting mechanism, an X-direction driving platform, a Y-direction driving platform, a turning tool base and a turning tool. The three-axis connecting mechanism comprises a three-axis connecting plate and a three-axis connecting frame, and the periphery of the three-axis connecting plate is connected with the three-axis connecting frame through an X-axis flexible hinge and a Y-axis flexible hinge; each flexible hinge is provided with a Z-axis flexible hinge point; the biaxial flexible hinge is at least provided with an X-axial flexible hinge point and a Y-axial flexible hinge point; the Z-direction displacement transmission mechanism, the three-axis connecting mechanism and the driver connecting rod are integrally designed. And a piezoelectric ceramic driver is adopted. The three-degree-of-freedom turning too