Reactionless capture of a satellite by a two degree-of-freedom manipulator

The specific topic considered in this paper, which plays a crucial role in on orbit servicing (OOS), is the autonomous capture of a target by a satellite-mounted manipulator. In this context, the trajectory generation techniques available to date have been designed for a servicing satellite, the attitude and position of which are actively controlled. The innovation in our work is the development of a reactionless trajectory generation strategy by means of which we attempt to find manipulator paths which will intercept the target without affecting the attitude of the base, thus avoiding the need for attitude control of the base during the operation of the arm. This strategy is based on the reaction null space (RNS) method, originally proposed by Yoshida, which allows on-line path generation and which appears to be the most manageable for implementation within a trajectory generation algorithm. Four novel algorithms, in increasing order of complexity, have been developed and implemented in Matlab. The simulations carried out show that it is possible to devise a reactionless capture trajectory satisfying all the constraints considered in the paper, despite the complication that the use of the RNS equations implies.