H-type air-bearing motion stage driven by linear motors

An H-type air bearing precise positioning stage driven by dual linear motors is established. Some key techniques, including design method of air bearing slider and synchronic-motion control of dual linear motors, are studied. The air-bearing sliders are designed by finite element method, and the pressure field distribution of gas film in the bearing gap is analyzed. Preload technologies are adopted to improve air bearing's static performance. The static experimental results show that the preload sliders developed by finite element method have high load capability and stiffness. The static stiffness in the vertical direction of X-slider is 276.9 N/μm and the Y-slider is 333.3 N/μm. The improved parallel structure synchronous controller based on velocity synchro-error is designed, which adaptively tunes the PID parameters on-line by the fuzzy controllers. The motion experimental results show that the improved synchronous controller has high synchronous precision, the velocity synchronous precision is higher three times than the common parallel control, and will be suitable for multi-motor synchronization control with strong mechanical coupling. The H-type air bearing positioning stage driven by linear motors has high load capability and high precision, and can be used in precision engineering area such as photoetching machine and optical inspecting equipments.