Model reference adaptive control of spacecraft attitude for a PNP satellite with unknown time varying input/output delays

In this paper, we develop a Direct Model Reference Adaptive Tracking Controller for mildly non-linear systems with unknown input/output delays. This controller can also reject bounded disturbances of known wave form but unknown amplitude, e.g. steps or sinusoids. This adaptive controller is then applied to the control of spacecraft attitude for a PNP satellite. The PNP satellite problem is a candidate for adaptive control due to errors in measurement and placement of sensors and actuators on the satellite. Further, all actuator commands and sensor outputs will be routed through a PNP data bus which will introduce unknown time varying delays into the system.