Optimization Of Attitude Control Components For High Control Precision Pico-Satellite

To improve the capability of the Pico-satellite in carrying out space missions,the sensor,actuator,spaceborne interference and controller of the satellite are designed and improved respectively for the satellite attitude control system.Among them,the attitude determination accuracy of the static infrared earth sensor is the premise of the accurate control of the Pico-satellite;the torque range of the strong maneuverability reaction wheel group determines the attitude response speed of the Pico-satellite;the vibration of wheel group is the most critical factor affecting the optical observation and attitude stability of Pico-satellite;and the design of the controller can directly affect the attitude control results of Pinar satellite.The results of this paper are as follows:(1)According to the characteristics of panoramic fish-eye imaging of the static infrared earth sensor,the imaging model is established based on single-slice infrared imaging,and an algorithm combining the interval vector product with the mean of the confidence interval of t location-scale distribution is proposed.Compared with the original algorithm,the standard deviation of the target attitude angle within ±10 degrees is reduced from 0.06 degrees to 0.03 degrees.(2)The vibration characteristics of the reaction wheel assemblies are analyzed in detail,the vibration model is established,and the fully coupled vibration model of the rigid body is added to the attitude control loop of the Pico-satellite.Then an adaptive momentum distribution jitter control is proposed for vibration disturbance of the reaction wheel.The target control torque distribution is adjusted according to the current speed of each reaction flywheel in order to limit the wheel speed to a reasonable range so as to reduce the jitter interference.The new control logic combined with a PD controller or SMC controller can significantly improve the attitude control accuracy of Pico-satellite.(3)In order to meet the control torque requirement of Pico-satellite,improved reaction wheel assemblies are designed,which can provide strong maneuverability.It has been proved that the control torque of the reaction wheel assemblies is five times higher than before.In summary,the attitude control system of high control precision Pico-satellite is studied,the algorithm of the static infrared earth sensor is improved,the vibration of the spaceborne wheel group is analyzed,and the adaptive torque allocation control algorithm is adapted to eliminate its effect.Finally,the reaction wheel assemblies with large torque output are developed.These works provide a scheme for enhancing the maneuverability and improving the control accuracy of the Pico-satellite,which is of the practical reference value.