Parameter identification of free-floating robots with flexible appendages and fuel sloshing

In this paper we adressed the effects of flexibilities and liquid fuel sloshing on the on-orbit robotics-based dynamic parameter identification. For modelling the liquid fuel sloshing we combined the general free-floating robot dynamics with a mechanical pendulum equivalent model. For the dynamic parameter identification we extended our identification algorithm for rigid body systems to account for these two effects. The flexible and sloshing modes are excited only with the manipulator executing optimized trajectories. For the identification algorithm we make use of the robotic joint position and torque sensor data as well as of on board GNC sensor data. Numerical simulations showed that the two effects can have significant influence to the free-floating dynamics. Furthermore, we showed that the extended parameter identification algorithm improves the accuracy of the dynamic model.