Active Disturbance Rejection Control Of The Reaction Sphere Actuator

The main content of this paper is the active disturbance rejection control of the reaction sphere actuator.The Euler angle is used to describe the rotor attitude.The singular problem exists when the reaction sphere actuator is maneuvering at large angle.In order to solve this problem,the quaternion is used as the attitude description and the law of rigid body rotation is combined to obtain the dynamic model of the reaction sphere actuator.In the existing literature,the force of a single permanent magnet and a single stator coil was obtained by finite element simulation,and the torque model of the reaction sphere actuator was obtained by accumulative method.The spherical harmonic function can be directly rotated.The spherical harmonic function is used to describe the torque model of the reaction sphere actuator.In this paper,the position current double closed-loop control are used.The active disturbance rejection control are used to overcome the disturbance caused by system model error and friction torque.The current loop is controlled by proportional integral control.When the current error is large,the proportional link plays a major role in tracking the given current.In the steady state of the system,the integral link plays a major role in eliminating the static error and reducing the system jitter.The current loop is set as a small inertia link to improve the dynamic performance of the reaction sphere actuator.Finally,aiming at the problem of satellite ground staring,the satellite's desired attitude is analyzed.The reaction sphere actuator is used as the attitude control device of the satellite.The relationship between the control torque of the reaction sphere actuator and its angular velocity is established.Then the dynamics model of the satellite based on the reaction sphere actuator is established.A second-order ADRC controller is designed for the reaction sphere actuator,and a proportional differential controller based on disturbance observer is designed to achieve satellite to ground staring task.