Research of cable deformation effects on synchronous accuracy of serial cable-driven sheaves

The serial cable-driven sheaves, wrapped by cables in a single-sided pattern, inevitably produce synchronous error for their cable deformation influences. The synchronous accuracy is a key technology for two spacecraft successful docking, which is mainly dependent on the adjustment of the preload on cable. This research on single-sided cable-driven sheaves is not well enough because of their complicated cable deformation behaviors under the preload. This makes them a low assembly efficiency and poor assembly quality in guaranteeing their synchronous accuracy. Thus, building a more precise model is essential between the preload and cable deformation in the assembly of the cable-driven sheaves. For this, considering both the way of the cable preload applied and their operating conditions, a predicting cable deformation (angle error) model is first proposed based on the stiffness of cable-driven sheaves. Then, some useful results are obtained through the analysis of the angle error influenced by three dominating parameters (wrap angle, preload, and friction coefficient) and of the parameter sensitivities to angle error. Finally, some experiments verified the model. This article provides a favorable attempt for better controlling the cable deformation and lays a foundation for further investigation on the synchronous accuracy and improving assembly efficiency of the serial cable-driven sheaves.