Abstract
“μ-LabSat”, a micro-piggyback satellite, was launched by an H-IIA rocket on 14 December 2002. One of its missions was to release truncated cone-shaped targets with representative dimensions of approximately 10 cm and evaluate the use of machine vision to estimate their position and attitude relative to the satellite. As a follow-on mission using the same camera, a three-axis attitude control moon-tracking maneuver was planned with the following steps: (1) recognize the moon in captured images and track it continuously, (2) calculate the median point of the moon, (3) control the satellite's attitude to move the moon's position in the image to the near the image center, (4) maintain the moon's position near the center of the image. μ-LabSat is a bias-momentum micro-satellite with two wheels, a configuration that is not normally capable of three-axis attitude maneuvers. This paper describes an algorithm “Sliding Mode Controller using Rodriguez parameter” that has been developed to enable such maneuvers, and presents the results of its evaluation by numerical simulation and the on-orbit moon tracking experiment.
