Attitude Control of a Micro-Satellite Using Reaction Wheels and Quaternion-Based PD Control

Micro-satellites and CubeSats have become increasingly important platforms for Earth observation, communications, scientific experiments, and technology demonstration. Despite their compact size and limited resources, these spacecraft require accurate attitude determination and control to maintain proper orientation and achieve reliable pointing of payloads, antennas, and solar panels. This study investigates the modeling and attitude control of a three-axis micro-satellite equipped with reaction wheels and a quaternion-based proportional-derivative (PD) controller. The spacecraft is modeled as a rigid body with three principal moments of inertia, and its nonlinear rotational dynamics are formulated using Euler’s rotational equations. Spacecraft orientation is represented by unit quaternions to avoid the singularities associated with conventional Euler-angle representations. The proposed control strategy uses quaternion attitude error and angular velocity feedback to generate the required control torque, while reaction-wheel torque saturation and external disturbance torque are considered to provide a more realistic representation of the control system. The performance of the proposed approach is evaluated in terms of attitude tracking accuracy, angular velocity regulation, and control effort. The results demonstrate the effectiveness of quaternion-based PD control for stabilizing the spacecraft attitude and reducing orientation errors, providing a practical framework for preliminary analysis and development of micro-satellite attitude-control systems.

کلیدواژه ها:

Micro-satellite ، CubeSat ، attitude control ، reaction wheel ، quaternion ، PD controller ، spacecraft dynamics