Predicting synchronous accuracy of the wire sheave drives

• The sheave drive under the study is wrapped by the rope in a single-sided pattern.
• A model used to predict the synchronous accuracy of sheave drives was developed.
• To improve the prediction accuracy, the model is modified by the experiment.
• The relationships between the synchronous accuracy and its dominating influencing factors were obtained.
• The study laid a foundation for further study of serial sheave drives, and for improving the efficiency of assembly similar to the docking mechanisms.

Wire sheave drives are used as transmission elements in docking mechanisms for their excellent flexibility, light weight and high intensity performance. The synchronous accuracy of sheave drives is vital to the docking of spacecraft and is achieved mainly by manual assembly. Due to the lack of further research in this aspect, assembly workers have to operate it for several cycles, which leads to lower assembly efficiency and quality. This paper takes two sheaves of serial drives as a typical example and establishes a prediction model for their synchronous accuracy based on the classic sheave equation. Then the prediction model is modified because of large error between the predicted values and the experiment results. The modified model captures the dominant trends under various operating conditions, and the predicted values also agree well with the experiment results. Thus, the modified model can be used to predict synchronous accuracy of wire sheave drives, to analyze the effect of dominating parameters and to test whether the preset parameters imposed on rope is appropriate or not. This lays a foundation for the study of serial drives and for further improving assembly efficiency and quality of docking mechanisms.