Abstract: An ultra-precision positioning stage based on laser-Moiré signals is developed, which takes a microcomputer as its core, adopts a laser moiré sensor to detect the position deviation, and can realize automatic ultra–precision nanopositioning by organic combination of optical, mechanical and electronic technologies. The stepping-motor drives the macro-stage by precise lead screw drive set, which can realize large–stroke micron positioning. The PZT drives the micro-stage, which can realize nanopositioning. In view of the existing nonlinearity and time-variation of the system, and the difficulty in achieving ideal control effect by conventional PID controller, the intelligent control of precision positioning based on BP neural network is proposed, which can effectively improve the dynamic and static performance and the repeatability of the positioning system. The experimental results show that the working stroke of the precision positioning stage can reach 50 mm, the positioning accuracy is ±10 nm and the positioning time is less than 30 s.

Key words: Intelligent control, Moiré signals, Nanopositioning, Neural networks