Multibody simulation of 1U CubeSat passive attitude stabilisation using a robotic arm

Robotics plays a crucial role in contemporary space missions, particularly in the development and use of robotic manipulators for performing multiple space operations in environments inaccessible to humans. In line with the current trend of integrating multiple functionalities into a single system, this study evaluates the feasibility of using a robotic manipulator, termed a C-Arm, also for passive attitude control of a 1U CubeSat. Specifically, utilizing a carefully simplified multibody model of the entire CubeSat system, the numerical simulations, assessed the use of the robotic arm first as a gravity gradient boom and subsequently, following the addition of a permanent magnet at the arm’s extremity, as a passive magnetic control mechanism for the nanosatellite. Despite the promising design, simulations indicated that the effectiveness of the C-Arm as a gravitational boom is significantly constrained by size (with the retracted arm occupying 0.5U) and weight (limited to 200g). However, it was demonstrated that under various initial conditions, the pitch angle consistently oscillates around ±40°, while the roll and yaw angles exhibit more variability, with maximum values of 30° and 35°, respectively. Further evaluations attempted to enhance pointing accuracy through the incorporation of permanent magnets. As expected, the absence of dissipative forces led to pronounced attitude instabilities, resulting in a temporary reduction in pitch angle oscillations. In conclusion, the concept of using a robotic arm integrated into a 0.5U CubeSat system for passive attitude control shows significant potential, particularly in missions where pointing can tolerate a considerable range, typical of CubeSat-type nanosatellite missions.