Path planning of free-flying space manipulators: an exact solution for polar robots

Abstract
Motion planning for free-flying robots can be quite complex due to the fact that any movement of the
joints influences the position andthe orientation of the spacecraft which carries the manipulator. Several
studies have been carried out to plan joint trajectories which eliminate the effects of the dynamic disturbances.
Approximate solutions to this problem have been proposedusing the concept of the Disturbance
Map. The authors have already studied this problem for the case of 2 DOF and 3 DOF planar robots connected
with revolute joints developing an exact solution based on the concept of dynamic singularities.
Aim of this paper is to extendthe proposedmethod ology to the case of planar polar manipulators, analyzing
the peculiarities of these robot arm configurations. A numerical procedure for the evaluation of zero
disturbance trajectories is also presented and application examples are developed.
The adoption of the proposed strategy improves the performances of spacecrafts attitude control
system.