Research On Dynamics And Control Of Spatial Multibody Systems Based On Pseudospectral Method

In recent years,with the rapid development of aerospace science and technology,especially the development of the space rendezvous and docking technology and the deep space detection technique,etc,lead to the scale and the degree of freedom of spatial multibody system becoming more bigger and more increasingly than before,and lead to the factors needed to considered sharp increasingly.As for the attitude dynamics and control problem of spatial multibody system,the attitude maneuver planning and attitude motion tracking is studied in this paper.The main content is as following:Firstly,based on the principle of angular momentum conservation,the dynamics equation of the underactruated spacecraft adjusted by two momentum wheels and the dual rigid body spacecraft connected by frictionless joint(ball-in-socket joint and universal joint)is deduced,so the kinematics equation of the free-fall cat doing twisting in the air does.Besides,the the kinematics and dynamics equation of an underactruated spacecraft actuated by the jet thruster are described through Euler attitude parameter.Secondly,the fundamental and feature of three conmmon pseudospectral methods(Gauss Pseudospectral Method(GPM)?Legendre Pseudospectral Method(LPM)and Radau Pseudospectral Method(RPM))are fully described and contrastively analysised.Next,the Newton Interpolation and the Chebyshev-Gauss Pseudospectral Method(CGPM)is employed to improve the GPM,respectively.At last,the fundamental and the steps of algorithm for the hp Adaptive Radau Pseudospectral Method are went into details.Thirdly,the GPM is employed to study the attitude maneuver planning problem for the underactruated spacecraft adjusted by two momentum wheels,and analsizing the influence on the optimization results as for the last adopted number and diffirent numbers of the Legendre-Gauss(LG)collection points.As for the underactruated spacecraft model actuated by the jet thruster,the attitude motion planning problem is researched and analysised based on minimum time and energy optimum by adopting the GPM?LPM and RPM,respectively.Considering the attitude optimal control problem(OCP)of the free-fall cat and the initial value sensitivity of SQP algorithm,this paper presented a hybrid optimization strategy combining the GPM to solve the feasible solutions with Derect Shooting Method(DSM)to solve the optimal solutions.In this paper,the CGPM is combined with a layered optimization strategy to study the attitude motion planning problem for the double rigid body spacecraft system connected by ball-in-socket,and theoptimization results are contrastively analysised with the results from GPM.At last,the hp Adaptive Radau Pseudospectral Method is employed to discuss the attitude optimal control problem for the dual rigid body spacecraft connected by universal joint,the results from pure h method and p method are also presented.Lastly,based on indirect Legendre Pseudospectral Method,this paper discussed the attitude motion tracking problem on the condition of existing external small initial disturbance for the underactruated spacecraft actuated by the jet thruster.This method can avoid doing the intrgral operation for the Riccati differential equation,so it possesses a faster computational speed.