Structural design, accuracy analysis, and mechanical calibration of a small two-component docking mechanism for large loads in space

Currently, the passive part of the space station platform's docking device has been finalized, emphasizing the need for a docking mechanism that enables the on-orbit assembly of large payloads using in-situ resources. This paper presents the design of a compact, high-precision dual-component docking mechanism for large space loads. First, we propose a parametric design for the active and passive sides, accompanied by the constraint equations for the capture mechanism. Next, a progressive positioning method, beginning with coarse correction and followed by fine correction, is proposed. The dual-component calibration and positioning performance are analyzed to initially capture large deviations and achieve high-accuracy docking of electrical and hydraulic connectors subsequently. Static analysis of both single and dual components reveals a positive correlation between load-carrying capacity and diameter. During the prototype testing, the maximum positional deviations were measured 0.12 mm in the X-direction, 0.5 mm in the Y-direction, and 0.07 mm in the Z-direction. The maximum angular deviation was 0.04° when the dual components operated together. Finally, the impact of axial and radial docking conditions in orbit was analyzed to verify that the loading requirements were satisfied. This work offers both theoretical and technical insights for the future development of docking mechanisms for large space loads.