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...

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...