Session
Frank J. Redd Student Competition 2021
Location
Utah State University, Logan, UT
Abstract
This paper examines the usefulness of variable inertia reaction wheels (VIRWs) for spacecraft attitude control as compared to traditional fixed inertia reaction wheels (FIRWs). The equations of motion were derived for a spacecraft with FIRWs and VIRWs. Quaternions were used to represent the spacecraft’s orientation. A Lyapunov-based controller was derived and used to control the attitude quaternion and angular velocity of the spacecraft with the two control variables being the reaction wheels’ inertia and angular acceleration. A Simulink/MATLAB simulation was created to test the response of the FIRWs and the VIRWs to spacecraft reorientation maneuvers and detumble maneuvers. The results showed that VIRWs performed better than the FIRWs when the VIRWs’ inertia was allowed to increase beyond the inertia of the FIRWs. When the VIRWs’ max inertia was limited to the inertia of the FIRWs then the FIRWs performed slightly better by reaching the desired attitude slightly faster. For a detumble maneuver the VIRWs required less total angular acceleration as the inertia of the wheels were decreased to slow down near the desired attitude rather than deaccelerating the wheels. Overall, the systems performed quite similarly when the VIRWs’ max inertia was limited to the inertia of the FIRW.
Spacecraft Attitude Control Using Variable Inertia Reaction Wheels
Utah State University, Logan, UT
This paper examines the usefulness of variable inertia reaction wheels (VIRWs) for spacecraft attitude control as compared to traditional fixed inertia reaction wheels (FIRWs). The equations of motion were derived for a spacecraft with FIRWs and VIRWs. Quaternions were used to represent the spacecraft’s orientation. A Lyapunov-based controller was derived and used to control the attitude quaternion and angular velocity of the spacecraft with the two control variables being the reaction wheels’ inertia and angular acceleration. A Simulink/MATLAB simulation was created to test the response of the FIRWs and the VIRWs to spacecraft reorientation maneuvers and detumble maneuvers. The results showed that VIRWs performed better than the FIRWs when the VIRWs’ inertia was allowed to increase beyond the inertia of the FIRWs. When the VIRWs’ max inertia was limited to the inertia of the FIRWs then the FIRWs performed slightly better by reaching the desired attitude slightly faster. For a detumble maneuver the VIRWs required less total angular acceleration as the inertia of the wheels were decreased to slow down near the desired attitude rather than deaccelerating the wheels. Overall, the systems performed quite similarly when the VIRWs’ max inertia was limited to the inertia of the FIRW.
