Micro-motion devices technology: The state of arts review

In this paper we review the world-wide study on micro-motion systems both from an academic and an industrial perspective. The objective of the review is to answer the following questions: (1) What are the limitations of technologies to develop a micro-motion device in terms of function, motion range, accuracy, and speed it can achieve? (2) What is any economic implication of these technologies? (3) What are future research directions? The micro-motion systems considered in this paper are classified into four kinds in terms of their motion ranges: (a) < 1 mu m, (b) 1 similar to 100 mu m, (c) 100 similar to 1000 mu m, and (d) > 1000 mu m. This review concludes that the PZT actuation element integrated with the compliant mechanism is the most promising technology which can achieve high accuracy (sub-nanometer) of all four kinds of motion ranges. This promise is further based on the amplification technology using the compliant mechanism concept. The amplification mechanism is used to compensate the problem with a limited stroke of the PZT actuation element. The compliant amplification mechanism allows one to achieve a high resolution and high stiffness motion which does not compromise the loss of accuracy due to motion amplification. The PZT actuation element and the compliant mechanism are both economically viable. Future research direction should generally focus on the interface between the PZT actuation element and compliant mechanism and the reliability of the compliant mechanism under cyclic deformation of compliant materials.