Attitude control of a space robot using the nonholonomic structure

This paper treats the attitude control of a space robot using the fact that a free-flying space robot can reorient its attitude only by moving the manipulators. We solve an optimal control problem formulated in a more general way than those of the problems to have been solved so far. That is, our approach can afford to solve the case where the initial and final postures of the manipulators are different and where the solution could not be a smooth and continuous function of time. The optimal control problem is discretized by the rectangular rule into a mathematical programming problem to be solved by the periodically preconditioned conjugate gradient-restoration algorithm. A space-robot model with a multi-link manipulator is used to exemplify the present approach.