基于机器视觉与柔顺控制的在轨轴孔对接技术研究

Research on In⁃orbit Peg⁃in⁃hole Docking Technology Based on Machine Vision and Compliant Control

在轨卫星燃料加注作业涉及失重环境下航天器间多管道同时对接的问题,对此设计了一种可固连辅助牵引/排斥对接作业系统。通过基于边缘信息的模板匹配算法和基于相机小孔成像模型的位姿测量算法进行非合作目标的视觉引导,在机构间建立牵引/排斥作用后,使用引入比例微分控制器的导纳控制算法进行多管道的柔顺插入与分离;借助搭载单目相机以及末端六维力传感器的机械臂实物平台进行验证实验。结果表明:视觉测算的水平方向误差不超过4 mm,可满足后续作业的初始位姿需求;柔顺控制算法能够避免作业过程中的卡阻问题,并将对接机构间的相互作用力与力矩分别保持在20 N以及0.8 Nm以内。系统能够在减少航天器间姿轨扰动的前提下完成小间隙长进深的多管道对接任务。

The in-orbit satellite refuelling operation involves simultaneous docking of multiple pipe-lines between spacecrafts in the zero-gravity environment.To address this problem,an auxiliary traction/repulsion docking system capable of solid connection was designed.A visual guidance sys-tem for non-cooperative target was implemented using a template matching algorithm based on edge information and a pose measurement algorithm based on the camera pinhole model.After establis-hing traction/repulsion effects between the mechanisms,compliant insertion and separation of multi-ple pipelines were achieved using admittance control algorithm with a preposed proportional-deriva-tive controller.A robot platform equipped with a monocular camera and a six-dimensional force sen-sor was established for experiments.The results showed that the horizontal position error of visual al-gorithm did not exceed 4 mm,meeting the initial pose requirements for subsequent operations.The compliant control algorithm could avoid jamming issues during the docking operation,and the inter-action forces and torques between the mechanisms were maintained within 20 N and 0.8 Nm,re-spectively.The system was capable of completing multi-pipeline docking tasks with small clearance and long insertion depth while reducing pose and orbit disturbances suffered by the spacecrafts con-ducting the mission.