| In recent years,the number of spacecraft sent into space reaches an outbreak due to the development of space technology.As the number of spacecraft increased,their function diversified.However,the increasingly complex functional requirements,for ex-ample,the aerodynamic moment interference of ultra-low orbit spacecraft,the structure interference of long time orbit maneuver,the attitude control system’s short lifetime of high orbit spacecraft,pose severe challenges to spacecraft platforms especially to tra-ditional attitude control systems.To solve these challenges,the attitude dynamics and control methods of spacecraft systems containing internal movable masses are studied in this paper.Three control methods are designed for the specific problems faced by three typical application scenarios.The main results of this paper are as follows:1、Dynamic modeling and analysis of a spacecraft containing movable masses are carried out.Firstly,the dynamic modeling of spacecraft system with movable masses is carried out,and the description method of rigid body dynamics without torque is studied.Then,three effects of particle motion are summarized: centroid change,angular momen-tum exchange and inertia tensor change,based on the dynamics of spacecraft containing movable masses.After that,the aerodynamic force of low orbit spacecraft is modeled and their influence to the attitude of the spacecraft is analyzed.Meanwhile,how to con-figure centroid position to get pitch and yaw stability is studied.Finally,the relationship between one-dimensional mass motion and the main body attitude motion is analyzed quantitatively.2、An adaptive structure compensation method is designed for structural inter-ference caused by unknown centroid deviation.Firstly,a three-moving-mass control system is chosen as the structure compensation actuator and the dynamic equation of the spacecraft system is refined.Then,three kinds of adaptive nonlinear state feedback con-trollers are designed for the problem of uncertain structure interference and related theo-retical analysis is carried out.An adaptive nonlinear angular velocity feedback controller is designed to realize estimation and compensation of unknown structure interference and meanwhile controlling the angular velocity of Y axis and Z axis.By applying a X-axis reaction wheel in cooperation with the moving mass control system,an adaptive nonlin-ear attitude feedback controller is designed to control the attitude of the spacecraft at the same time estimating and compensating the structural interference with no system error,which is the shortcoming of the adaptive nonlinear angular velocity feedback controller.At last,a variable sliding surface adaptive fast attitude feedback controller is designed to realize fast convergence of attitude angle compared with the adaptive attitude feedback controller.3、A novel three-axis attitude stabilization method for low-Earth orbit space-craft is designed aiming at the instantaneous underactuation problem of movable mass control system.In order to make full use of two effects of moving mass motion,a control system composed of four in-plane movable masses is designed.With the different combination of the two paired masses,the aerodynamic torque as well as the effect of angular momentum exchange in body coordinate system can be introduced to the system.Then,a novel three-axis attitude stabilization method of the low-Earth orbit is designed.The method is composed of three cascade control modes,namely,angular momentum control mode based on aerodynamic torque,detumbling control mode based on internal relative motion and stabilization mode based on aerodynamic torque.An optimal control method is adopted in angular momentum control mode to reduce the angular momentum in the orbit plane to zero,and the convergence of the method is proved theoretically.While in the detumbling control mode,a nonlinear controller is used to control the spacecraft to a simple rotation around the Y axis.Finally,the stabilization mode based on aero-dynamic torque is to further control the spacecraft attitude error to zero by using sliding mode control method,and the convergence is proved by Lyapunov indirect method.4、A novel reorientation control method for spacecraft in inertial space using movable masses is designed to solve the problem that limited moving range mass motion can not realize the global attitude reorientation.Firstly,the configuration of a three-mass control system for attitude reorientation control is defined and the dynamic equation is refined.Then,a small angle attitude reorientation control method based on the sliding mode control technique is designed for realization of small range attitude reorien-tation by controlling the motion of three masses in the limited moving range.After that,a global attitude reorientation control method is proposed by combining reciprocating mo-tion of movable masses.Principle of the method,the acquisition method of candidate matrices and the path planning method for the reorientation are described in detail.The feasibility of the reorientation method is expressed by introducing two lemmas.In the end,the combination of global reorientation method with the small-angle attitude reorientation method is proposed to realize high precision attitude control.In a word,the attitude control method of spacecraft using movable masses is deeply studied in this paper.The control systems are designed and the adaptive structure com-pensation method of spacecraft,the three-axis stabilization method of low-Earth orbit spacecraft and the attitude reorientation method of spacecraft in inertial space are pro-posed.Relevant research results of this paper can be applied to low-Earth orbit spacecraft,space observation platform and deep space explorer.The research of this dissertation can provide broad reference for engineering application. |
