Nano-positioning is the key to any ultra-precision machines to achieve very fine movements with the resolution of a few nanometres while keeping a high stiffness. This paper presents a feeding module for a nano-positioning system in our newly developed multi-functional ultra-precision machine. The module includes the following key components: (a) a PZT actuator, which is used to provide a fine feeding movement, (b) a pair of capacitive sensor with a noise-limited resolution of 0.07nm, which is used to measure the movement and feed back to the PZT actuator controller, so that a positioning accuracy of a few nanometres becomes possible, (c) a pair of linear bearing guide for guiding the movement and guaranteeing the stiffness of the system, (d) a quartz force link for measuring the real time machining force, and (e) control systems for the above actions. The paper discusses the functions of all the parts and demonstrates the design considerations for achieving the high precision and stiffness at the same time. The system is an integrated module and can be used in machine tools for micro/nano-cutting, grinding, polishing, or measurement devices.
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