ROBUST COORDINATED CONTROL OF A SATELLITE-MOUNTED MANIPULATOR WITH CONSIDERATION OF PAYLOAD FLEXIBILITY

摘要

Tasks performed by a satellite-mounted manipulator include manipulation of large-scale and small-mass payloads such as spacecraft with large solar paddles and large pieces of the space station. The manipulated objects generally have high flexibility ,that is, their lowest natural frequencies are very low. Therefore, in controlling such rigid body payloads there is the possibility of coupling between the flexible payload motion and the attitude control system. Because of this coupling, the satellite or payload may be uncontrollable .To cope with this problem, this paper proposes a coordinated control method which considers payload flexibility .In this method , a nominal payload model is constructed considering the rigid mode and a few of low frequency modes .Other higher frequency modes and variations of coupling coefficients are regarded as modeling errors. If appropriate control parameters are chosen considering the modeling errors, stability of the system can be guaranteed. The proposed control method also has high robustness and small computation cost. The validity and usefulness of this scheme are verified through results of computer simulations.