Testing and investigations of reaction wheels

The first part of the paper presents the results of measurements on torque and force irregularities of running reaction wheels. Six different, current technology European wheels, both with ball- and magnet bearings, and with d.c. and a.c. drive motors are examined. Time-domain behaviour around zero wheel speed as well as noise at certain...

Accurate spacecraft attitude estimation with the ESA starmapper

The ESA starmapper is an optical-electronic instrument with an array of photo-sensitive slits, to "be strapped down to spinning spacecraft. Recorded times of passage of known stars over these slits, together with mathematical models for spacecraft dynamics and starmapper instrument, provide the basis for recursive estimation of the spacecraft...

In-orbit experiment with an attitude control algorithm for ANS based on modern control principles

The existing fine attitude system of the Astronomical Netherlands Satellite was designed on the basis of conventional digital control techniques. The possibility of a more advanced approach is presented in this report. As an example, an alternative control algorithm for the scan mode has been developed with the use of state estimation and state...

Survey of modern control and observation theory for disturbed, target following aerospace systems. Part one: Basic theory

The document contains a general theory towards the observation and optimal control of disturbed, target following aerospace systems. Disturbed, target following aerospace systems eire defined as aerospace systems that are designed to track a moving target system, while they are subjected to external, time-varying disturbances. The first five...