Nonlinear tracking control of rigid spacecraft under disturbance using PD and PID type ℋ∞ state feedback

This study investigates six degrees-of-freedom nonlinear tracking control of rigid spacecraft under external disturbances. We propose two nonlinear tracking controllers having disturbance attenuation ability, namely, a proportional-derivative (PD)-type H_∞ state feedback controller and a proportional-integral-derivative (PID)-type H_∞ state feedback controller. Both these controllers have positive definite gain matrices whose conditions to be satisfied are given by linear matrix inequalities. The properties of these controller are compared and discussed through numerical studies.