Modeling And Control Of Satellite With Large Rotating Components

With the development of space technology,a kind of satellite with large inertia rotating components has emerged.Such satellite is different from the traditional satellite because it has large inertia of rotating components.On the one hand,the mass distribution of large inertia rotating components is often uneven.On the other hand,the satellite will be influenced by installation error,vibration in the process of emission.Therefore,the large inertia rotating components often has imbalance problems,causing unbalance torque and affecting the precision of satellite attitude control and even leading to the failure of the task.Therefore,for satellites with large inertia rotating compoents,it is of great significance and research value to analyze the influence of unbalance of rotating parts and design control strategy to achieve its high-precision control.In this paper,the dynamic and kinematic models of the satellite with large inertia are established,and the dynamic model is analyzed.then the unbalanced disturbing torque is separated from the dynamic model,and the nominal model of the satellite with large inertia is established.According to the expression of unbalanced disturbing moment,the characteristics of unbalanced disturbing moment and the factors affecting its magnitude are analyzed.Aiming at the measurement noise and measurement error problems existing in practical application,a combined attitude estimator of gyro and star sensors is designed by using extended kalman filter method,and an attitude angular velocity filter is designed by using dynamic equation to effectively correct the measurement error and filter the influence of measurement noise.The simulation results show that the precision of attitude control is mainly limited by the precision of attitude determination,and the proposed control strategy and attitude determination strategy can realize the high-precision attitude control of the satellite with large inertia under the influence of imbalance.Aiming at high accuracy control problem with large rotating parts of satellite,respectively based on disturbance observer is designed PD control strategy and exponential reaching law of sliding mode control strategy,the former of the unbalanced interference by disturbance observer to estimate,and introduce the estimation of unbalanced torque compensation in the PD controller,and on the basis of disturbance observer is proposed an improved disturbance observer,join the estimate of the disturbing torque derivative,effectively improve the disturbance torque estimation precision.The latter uses the exponential approach law to design the sliding mode controller,uses the characteristic of bounded unbalance interference,selects the appropriate switch term gain to suppress,and performs the simulation verification,the proposed control method can effectively suppress the influence of unbalance interference.