A defect identification approach of operations for the driving element of multi-duty parallel manipulators

In order to improve the machining efficiency and the flexibility of manufacturing system, the study of multi-duty parallel manipulators has attracted the interest of some researchers. In this paper, according to the effects of different operations on the driving element, a demarcation diagram for distinguishing different duties, such as statics, low-speed but heavy-load, high-speed but low-load and high-speed but heavy-load, is proposed, and a defect identification approach to prevent the occurrence of defects for multi-duty parallel manipulators is presented. Taking the 1PU+3UPS parallel manipulator as an instance, an analysis method to the statics and dynamics is investigated by means of the screw theory and the proposed virtual screw. Based on the numerical example, the results show that the classification and practicability of operations can be accurately identified by the proposed demarcation diagram and defect identification approach, respectively.