Design and Development of Composite Linkage Mechanism for Cable-Driven Segmented Manipulator to Increase Synchronous Accuracy and Transmission Distance

Cable-driven segmented manipulators (CDSMs) have high dexterity and large bending characteristics with less motors, which have great potential for long-range manipulation in structured environment. However, as joints' number and segments' length increase, the synchronous performance will largely decrease due to friction and deformation. This letter presents a composite linkage mechanism for CDSM to improve the synchronous accuracy and increase the transmission distance. The design concept is first introduced based on the analysis of the traditional design. Then, composite linkage mechanism is proposed to overcome the shortcomings of single linkage mechanism. It is composed of short linkage mechanisms and long linkage mechanisms, where the former and the latter are respectively used to constrain adjacent and non-adjacent joints. Subsequently, four types of linkage mechanisms are designed in details. Furthermore, the construction rules of linkage mechanisms are also established, and a typical design example is provided. Finally, a prototype is developed and typical experiments are conducted. The experiments results show that compared with traditional design, the developed composite linkage mechanism can significantly improve the synchronous accuracy and increase the effective transmission distance.