Proposal of reducing impact force control system for scan stage with decouplable structure of coarse and fine parts

The upsizing and obtaining higher control accuracy are required for many large industrial machines. However, the requirements are trade-off against each other from the viewpoint of the conventional machine structure. In this paper, a novel structure of high-precision prototype stage consists of coarse driving part and fine driving part, which can be uncoupled with each other, is developed. In this case, the fine part can be simplified so that it would be more rigid and has higher resonant frequencies. One problem of the structure is that the impact between the fine part and the coarse part would be easily occurred at the beginning of the acceleration/deceleration. Therefore, we also design an practical control approach for reducing the impact force to improve the control performance. A control approach is also proposed for reducing the impact force between the coarse part and the fine part. The effectiveness of the proposed approach is verified via simulations and experiments.