Disturbance Observer-based Attitude Control of The Air-Bearing Platform using a Reaction Wheel

A reaction wheel is a well-known actuator for controlling the attitude of a spacecraft. It is a momentum exchange device that typically consists of a brushless direct current motor with a flywheel attached to its shaft. As the reaction wheel works, a disturbance that is sourced from the motor and its impact can occur. This paper addresses a linear disturbance observer-based attitude control system employing a reaction wheel on a rotational platform called air-bearing. Simulations run show effectiveness of the proposed controller. Integral Squared Error, Integral Absolute Error, Integral Time-weighted Absolute Error as well as control efforts are calculated for evaluating the simulation results. Overall, the simulations carried out show that the proposed disturbance observer-based controller is promising since it implies lower performance indexes comparing without the disturbance observer. Besides, some certain high control efforts would imply a reduction of the disturbance effect. Another interesting fact is a continuous form of the estimated disturbance constructed from the proposed linear disturbance observer is able to attenuate effect of the disturbance with nonlinear-discontinuous property.