Robust Fractional Order PDD Control of Spacecraft Rendezvous

A robust Fractional Order PDD (FOPDD) controller is designed for a nonlinear spacecraft rendezvous subject to uncertain conditions considering actuator saturation. The controller is designed for the linear and decouples system. It is applied on nonlinear uncertain system in large maneuverings. In order to design the FOPDD controller, the specifications are calculated through the phase margins, sensibility function and robustness constraints. The controller parameters are obtained through Particle Swarm Optimization (PSO) due to high convergence speed, low computation, easy simulation and rapid response. The simulation results indicate the designed FOPDD controller can track the desired trajectory in the composite uncertain condition (considering constant, impulse and sinusoidal disturbance, parametric uncertainty and sensor noises). The FOPDD performance is compared with the classic PDD controller for nonlinear model. The simulation is based on the SPHERES project.