Slew maneuver control under wheel constraints and precision attitude determination of observation satellites

Abstract

Satellite technology has influenced our ordinary life in the various aspects such as weather forecast, GPS navigation, satellite TV, overseas telephone and so forth. Increasing requirement on national defense has spurred the advancement of satellite technology as well. In a modern war, it is beyond imagination to exclude the help of satellites. According to diverse missions, satellites can be broadly classified into three parts: communication, remote sensing and space science exploration. No matter what missions given, the attitude control of satellite is primarily required in order to achieve the given objective successfully. Frequently the requirement of attitude control concerning payload mission drives whole system requirements. The common idea of conservative design for a satellite is changing with a success of high performance small satellites. The technical advance of VLSI and high performance CPU motivates the study of effective and compact satellites. Short term, low cost, small satellite projects have made it more versatile to design a control system of a spacecraft nowadays. From this standpoint, we have investigated control algorithms that can be used for small satellites mainly. The purpose of this dissertation is to study practical design methods about the attitude control system under the constraints attributed to small satellites. In the practical view point, the small satellite has many limitations of mass, volume, power, cost and so on. The primary interest of this thesis is to find out methods to overcome these constraints. We developed a near minimum time slew maneuvering control algorithm since a satellite needs to point a specific target in order to fulfill its mission. This algorithm is based on an idea utilizing the maximum capacity of a wheel under saturation constraints. A nonlinear observer is designed for estimating states optimally. The extended separation principle of nonlinear systems enables to design the controller and observ...