Journal of Astronautics ›› 2015, Vol. 36 ›› Issue (2): 133-141.doi: 10.3873/j.issn.1000-1328.2015.02.002

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Monocular Visual Servo Control System Scheme for Tethered Space Robot

CAI Jia, HUANG Pan feng, WANG Dong ke, ZHANG Bin   

  1. 1.Research Center of Intelligent Robotics, School of Astronautics, Northwestern Polytechnical University,Xi’an 710072,China;
    2.National Key Laboratory of Aerospace Flight Dynamics, Northwestern Polytechnical University, Xi’an 710072, China
  • Received:2013-11-12 Revised:2014-02-10 Online:2015-02-15 Published:2015-02-25

Abstract:

In order to solve the problem of non-cooperative target recognition during short-distance rendezvous for the TSR, a prototype framework of servo control system using monocular-CMOS is proposed in this paper. Aiming at the problems resulted from small template matching with large scene, such as low robust and long time-consumption, a novel template matching algorithm is used in the system. First, the novel matching algorithm uses a hollow annulus structure according to FAST algorithm to make the method be rotation-invariant and help to decrease the accumulative error caused by the changes of background. The matching criteria is composed of gray and gradient differences between template and object image, which restrain the impact of noise and illumination. Then, a dynamic template update strategy is designed to avoid tracking failures brought about by wrong matching or occlusion. Finally, the algorithm combines the least square integrated predictor with the PD controller, thus realizing real-time tracking and approaching non-cooperative target under complex circumstances.

Key words: Tethered Space Robot, Template matching, Object recognition, Visual servo

CLC Number: