Modeling and high-precision control of a ball-screw-driven stage

The demand for high-precision stages has received great attention due to the progress of nano-technology in recent years. Systems to provide long-range and high-precision performance for positioning, tracking and contouring actions have become stringent issues. Among these systems, the ball-screw-driven systems have been widely used in industrial applications and academic researches. In such systems, the friction behavior dominates the resulting performance and is usually known as the stick-slip phenomenon. The friction dynamics can be divided into the static and the dynamic regimes according to the conventional usage. In this paper, friction models are introduced to describe the dynamic behavior of a conventional ball-screw-driven x–y stage. The coherence between the theoretical and experimental data supports the validity of these models. Two sets of controllers corresponding to the static and the dynamic friction models are proposed based on the integral type sliding mode control (SMC) law. Experimental results demonstrate that the system achieves high-precision (10 nm) and long-range (10 cm) positioning performance with repeatability and robustness by the proposed control approaches.