Research On Direct Parametric Approach To The Quarternion-based Spacecraft Attitude Control

Spacecraft attitude control problem has always been challenging and hot,and it can be widely applied on many space missions,for instance,spacecraft formation flying,tracking,and observing for targets.However its nonlinear features make the spacecraft attitude control problem complex and difficult.Since the Euler angles are not suitable to describe the large attitude angular maneuver,the paper chooses the quaternion to describe the problem of large attitude angular maneuver and tracking,and utilizes the direct parametric approach to deal with the problem.First of all,this paper introduces two methods to describe spacecraft attitude,which are Euler angle representation and quaternion representation,then compares the two methods.To use the direct parametric approach,this paper introduces a secondorder nonlinear quaternion-based control system which takes no approximation.Additionally,the control system is based on the dynamical and kinematical equations of spacecraft attitude.Furthermore,on the consideration of the quaternion-based spacecraft attitude control problem built by this paper,the paper uses a direct parametric approach to design state feedback controller to solve the spacecraft attitude control problem.Compared with controllers designed by other nonlinear control ways such as sliding model control,controllers designed by direct parametric approach have two advantages.The first advantage is that the direct parametric approach can turn a high nonlinear spacecraft attitude system into a constant linear system with arbitrary eigenstructure.Since the stability,kinematical features and many other systemic performances of a constant linear system mainly rely on the eigenstructure of the constant linear system,the advantage has general utilities.The second advantage is that the process of design of the controller by the direct parametric approach has degrees of freedom,which can be further utilized to optimize the system performance.Thus the direct parametric approach has high applicability and degrees of freedom.Moreover,this paper deals with the quaternion-based spacecraft attitude maneuver control problem.This paper firstly designs a parametric controller for the nonapproximate second-order nonlinear quaternion-based attitude system which is the controlled spacecraft.Then,with the practical numerical input parameters,the state response of the close-loop system and the output of controller are plotted in MATLAB.Due to the two advantages,which are high degrees of freedom and constant linear close-loop system with desired eigenstructure,the paper can successfully designs prospective robust controllers which are in the limitation of output and good closed-loop eigenvalue sensitivity.Finally,the extend problem of attitude maneuver control,which is attitude tracking control is discussed in the paper.This paper provides the expression of error equation of the second-order nonlinear quaternion-based attitude system.Then it utilizes the direct parametric approach to design the state feedback controller.Furthermore,the paper optimizes the controller by its robustness,limitation of controller output and closed-loop eigenvalue sensitivity.Finally,the controller are used in practical system and the paper offers the state response of the close-loop system and the output of controller.The controlled spacecraft can successfully track the mobile target in the MATLAB simulation.