Quaternion based fuzzy gain scheduled PD law for spacecraft attitude control

In this paper a linguistic approach for fine-tuning PD controllers via fuzzy gain scheduling is presented. Among various merits of fuzzy logic based controllers, online tuning is in the center of attention. Demonstrating the usage of fuzzy gain scheduling PD law, spacecraft attitude control is utilized and thanks to quaternion error terminology, quaternion based fuzzy gain scheduling PD controller is introduced. Also as an index for comparing this control law to conventional methods, EULERINT is employed. Simulation results for both small and large attitude commands, utilizing linear and nonlinear spacecraft dynamics, depict better control performance in terms of shorter settling time and eradicating overshoots and steady state errors for fuzzy based approach. Reduction of the overall angular path followed by spacecraft is also concluded, which illustrates the superiority of the fuzzy gain scheduled PD law.