Dynamic performance of a long-stroke fast tool servo system

Abstract

A fast tool servo (FTS) system can be used to efficiently manufacture optical freeform surfaces. This paper investigates the dynamic performance of an FTS system driven by a voice coil motor and guided by air bearings. A simulation model and testing platform are developed to evaluate the load capacity and stiffness of the air bearings. The mechanical dynamic performance of the designed FTS, including modal and harmonic analyses, is assessed using finite element analysis. A nonlinear relation between air-bearing stiffness and mechanical bandwidth is obtained. The working dynamic performance is tested through system runout, tracking performance, and closed-loop tests. Quantitative relations between air-bearing stiffness and the mechanical and working bandwidths are established and analyzed. Machining experiments verify the feasibility of the FTS system with 31.05 N/ μm stiffness air-bearings.