Formation Configuration Design And Intergrated Dynamics And Control Of Fractionated Spacecraft

Fractionated Spacecraft is a virtual spacecraft system which is constituted by wireless connection, which has flexibility, scalability, maintainability and rapid response capability in orbit, so the research on it has an important significance in accelerating the speed of rapid response space system construction, enhancing the innovation capability of space technology and improving the level of development of a new spacecraft. Space circular formation configuration design of fractionated spacecraft is studied, to meets the need of energy transfer and data exchange accurately between the modules, and its application requirements. For the formation configuration keeping problem, the problems of fractionated spacecraft orbit and attitude integrated dynamics and control are studied, which avoids the disadvantages of designing the traditional attitude and orbit contoller respectively. The major contents of this paper consist of the following parts.For the problem of formation configuration keeping, unperturbed relative motion model is established through the difference of mean orbital elements. And the design steps of the space circular formation configuration is given. The J2 invariant perturbation conditions are no longer applied, so the revised formula is proposed through the quantitative analysis of J2 perturbation. The simulation results show that the revised formula can effectively inhibit the trace direction drift of formation configuration. It is necessary take control of the spacecraft, since the revised formula is just inhabit rather than suppress the divergent trend of the error of relative posstion between chief and deputy spacecraft.For the problem of fractionated spacecraft orbit and attitude integrated dynamics modeling, using the framework of dual quaternion, the dual quaternion description of traditional parameters are given. The single spacecraft orbit and attitude intergrated dynamics model is proposed, and then extended to the two spacecraft relative orbit and attitude intergrated dynamics model, which can describe relative attitude and orbit motion between spacecraft. The final form is simple, so the singularity and tedious operation of traditional method is avoided. This relative dynamics model can be used to design integrated controller.For the problem of fractionated spacecraft orbit and attitude integrated control, two tracking problems of formation configuration keeping are proposed, and the intergrated controllers are designed respectively. Chief spacecraft is working in predetermined orbit while tracking the desirable attitude motion in the task. The feedback linearization- generalized PD controller and approximation function-sliding mode controller are designed for chief spacecraft, and the simulation results are presented to validate the effectiveness of the control algorithm. The motion of deputy spacecraft relative to the virtual chief spacecraft satisfied the designing trajectory and tracking the desirable attitude motion in the task. The improved robust adaptive controller is designed for deputy spacecraft, and the simulation results show that the controller can effectively suppress the output saturation of the actuator.