A Six-degrees of Freedom Fine Motion Mechanism (3rd Report)

Multi-degrees of Freedom Motion and Reduction of Influence of an Extra Mass

Abstract

The purpose of the study is to establish the six-degrees of freedom (dof) fine motion mechanism which has the following characteristics : (1) each of the six one-dof motions has the same control characteristics as the theist (2) each one-dof motion does not interfere with the others. In the previous study, the mechanism was theoretically designed so that the open-loop characteristics of the six one-dof motions were the same, and so that there were no static and dynamic interferences between the motions. Then an experimental mechanism was made and the six one-dof motions were controlled. In the present study, it is shown that because the six one-dof motions have the same characteristics, the mechanism can make special dynamic motions which other fine motion mechanism cannot make easily. When an extra mass is loaded on the object, dynamic characteristics of the mechanism change from designed ones and the dynamic interference between the one-dof motions occurs. A method to transform the dynamic characteristics into the designed ones and to eliminate the interference is discussed.