Novel Demonstration of Six-Degree-of-Freedom Orbit Raising and Control using Two Electric Propulsion Thrusters

摘要

In this research work, we have developed an innovative geostationary satellite platform fully based on only two electric propulsion (EP) system thrusters. The novel demonstration of six-degree-of-freedom (6-DOF) control is carried out using only these two EPS thrusters. These thrusters are mounted on a manipulator arm. Any space object has six-degree of freedom, these are three translational and three rotational motion. The translational motion control leads to orbit control; likewise, rotational motion control provides attitude control. So, we need at least six thrusters to accomplish 3-axis attitude control, with tetrahedral wheel configuration for fine attitude control and station-keeping operations. Additionally, we require thrusters to be configured for orbit raising operations. But here as a proof of concept, we demonstrate through simulations, 6-DOF attitude control and orbit raising operations using only two EP thrusters with wheels for attitude control. This system when implemented will be advantageous in-terms of mass saving. These two thrusters are mounted on two three link robotic manipulator arms. Hence, we have carried out high fidelity modelling of these three link robotic arms with revolute joint. This is then used to study the possibility of getting 3-axes required force and torques, required to perform and demonstrate 6-DOF attitude and orbit control. The robotic arm has capability to generate many combinations of thrust and torques. From the high fidelity simulations, the orbit raising maneuver is carried in the GEO transfer orbit (GTO) for 9 Hrs., with the use of 300mN thrust. The East/West or North-South Station-keeping maneuver is performed at GEO to demonstrate orbit maintenance. The momentum dumping is performed to for wheel speed desaturation. Thus demonstrating QUAD (quadrilateral) control by using only two EP thrusters.