Proposal of fast and high-precision control for ball-screw-driven stage by explicitly considering elastic deformation

Ball-screw-driven stages are extensively used in industry for long-range and high-precision fabrication thanks to their high efficiency and high ability to apply/withstand high thrust loads. However, spring-like nonlinear friction in zero-speed region significantly affects the control performance. In this paper, the mechanical deformation characteristics at zero-speed point after low deceleration and after high deceleration are analyzed. It is found that the mechanical deformation characteristic of fast motions differs from the case of slow motions in zero-speed region, and therefore performing friction compensation should take the motion conditions into account. Then, after introducing a variable to evaluate the elastic deformation of the total mechanical components, a novel friction compensation method for fast reverse motions using Sigmoid function is proposed to enhance the control performance by explicitly considering the elastic deformation. Finally, Experiments are performed to verify the effectiveness of the proposed method.