Application of H∞ design on ATV control loop during the rendezvous phase

The Automated Transfer Vehicle (ATV) is a European cargo transfer vehicle designed to contribute to the logistic servicing of the International Space Station (ISS). During the final approach to the docking port, several disturbances can degrade the performances at mechanical contact. This paper shall focus on the design of the ATV position controller used for final approach and it is organised as follow. The general problem of ATV to ISS docking is first described, and especially the different Guidance, Navigation and Control (GNC) functions requirements as well as the environmental perturbations likely to disturb the control loop. In a second part, discrete H. control approach is applied to the position control loop. Methodology, design and tuning are then fully described and illustrated with ATV application. At last, GNC algorithms performances are presented to show their compliance with the requirements.