Fractional order PDD control of spacecraft rendezvous

In this study, a rendezvous mission between two spacecraft is programmed. The system is modelled as a 6-DOF formation flying. It is expected that this system be robust against various uncertainties and disturbances while minimizing the energy consumption, considering thrusters and control torques limitations. For this purpose, three robust fractional-order PDD (FOPDD) controllers are designed. The first one is designed based on robust constraint on transfer function. In the second method, the controller gains are tuned by using Particle Swarm Optimization (PSO) algorithm. The third designed controller is implemented according to Model Reference Adaptive Controller with Fractional Order Adjustment Rules (FOAR-MRAC) which is a combination of FOPDD controller tuned by PSO algorithm and an adaptive time variable gain. The performance of these controllers are compared in-various uncertain conditions (disturbances, mass and inertia uncertainty and sensor noises) considering actuators limitations.