Linear Stages for Next Generation Precision Motion Systems

This paper presents the design, fabrication, and testing of two linear stages for next generation precision mechatronic motion systems such as in semiconductor photolithography machines. We have designed a new linear iron-core permanent-magnet motor that can simultaneously achieve high force and low noise, providing a promising candidate for actuating systems for high-throughput and high-precision servo applications. The vibro-acoustic noise mechanism of linear iron-core synchronous motors and a new magnetic design approach to mitigate such noise issue are presented in this paper, along with the experimental validation of significant higher-force and lower-noise performance as compared to a conventional linear iron-core motor. In this paper, we also present another type of novel linear stage for in-vacuum transportation tasks in precision manufacturing systems. This new linear stage system is driven by a hysteresis motor and magnetically-levitated with two-degrees-of-freedom (DOF) active bearing controls and three-DOF passive magnetic bearings. This paper discusses the design, operating principles, and experimental results of this magnetically levitated linear motor system.