Model Predictive Controller for 3-dof free floating platform with binary actuated thrusters and reaction wheel

Air-bearing-based platforms are used to simulate microgravity on earth. Therefore, these platforms can be used to test for example Active Space Debris Removal (ASDR) maneuvers. European Space Agency’s Orbital Robotics and GNC Lab (ORGL) features a 5m ⇥ 9m flat floor. A 130 kg heavy air-bearing platform combined with a cold gas propulsion system with eight thrusters and a reaction wheel stacks up to a satellite simulator.
The thrusters can only be on/o↵-actuated while having time constraints on opening and closing times of the valves. The existing control scheme based on an online trajectory optimization and a TVLQR does not respect these constraints and therefore shows a not satisfying performance on the real system. The goal of this thesis is the development of an MPC controller for the platform which directly controls the thrusters, considering the on/o↵ behavior and the timing constraints to enable (thrust-) optimal control. The underlying optimization problem can be solved as a mixed integer problem, although existing works also solve the problem as a quadratic problem, for example, by reformulations or restrictive assumptions. However, none of the existing works solve the problem with the constraints as described above. For providing an MPC controller, in my thesis I will compare di↵erent problem formulations and solvers to be able to control the platform in real time.