Modeling Flexible-Body Dynamics in Real-Time Robotic Systems used in Satellite Servicing Simulations

Satellite failures on-orbit that once led to end-of-life may eventually be remedied using robotic servicing platforms. A key element of this scenario is the physical interaction between two free-floating spacecraft, including both relative translation and rotation of either vehicle. This paper aims to model a spacecraft with flexible appendages in order to ultimately assess whether or not any flexible modes will be excited during grappling by the robot servicer. If these flexible modes are excited, the resulting motion could make it difficult to establish contact or possibly damage the satellite. If the addition of flexible motion to the current satellite model significantly contributes to the overall resulting motion, it will motivate the need to avoid exciting flexible modes. This paper focuses on the derivation of a combined rigid and flexible body satellite model implemented in both MATLAB and C++. The flexible dynamics of the continuous beam model is validated against the ADAMS software package and is deployed on a robot to simulate the initial phases of a satellite servicing mission.