2007 Volume 50 Issue 167 Pages 63-69
When a satellite separates from the launch vehicle, an initial high angular rate or a tip-off rate is generated. B-dot logic is generally used for controlling the initial tip-off rate. However, it has the disadvantage of taking a relatively long time to control the initial tip-off rate. To solve this problem, this paper suggests a new detumbling control method that can be adapted to micro/nanosatellites using a pitch bias momentum system, and presents simulation results. The proposed detumbling method was able to control the angular rate within 20 min, which is a significant reduction compared to conventional methods. In addition, the momentum wheel initial start-up must be done under stable conditions, and a conventional pitch spin-stabilized initial wheel start-up method is commonly used. Since the conventional wheel start-up method cannot be used if the detumbling controller proposed by this paper is used, a method is also proposed for bringing up the momentum wheel speed to nominal rpm while maintaining stability. The performance of the method is compared and verified through simulation. The overall results show a much faster control time compared to the conventional methods, and achievement of nominal wheel speed and 3-axis stabilization while maintaining stability.