Spacecraft Relative Position And Attitude Integrated Adaptive Control Based On Dual Quaternions

With the development of space technology, unmanned autonomous on-orbit servicing is becoming the development tendency of on-orbit servicing technology. And, relative position and attitude control is one of the key technical foundation to achieve the on-orbit servicing mission. Focused on the couped control problem of spacecraft which performs proximity operations, an integrated dynamic modeling method and several corresponding integrated control algorithms has been investigated in this dissertation. The main contents are as follows:Firstly, investigated on the method to describe the spacecraft general motion including translational and rotational motions based on dual quaternions, and explained the physical meaning of this description method. In addition, the integrated dynamic model is established based on dual quaternions.Secondly, by using the vector part of dual quaternions as system states, system equations in the form of matrix multiplication are derived. This form of system equations is propitious to many control theory deduced in the form of matrix. Using these system equations, an adaptive backstepping controller is designed using the backstepping method in the nonlinear system theory and model reference adaptive control theory. To compare with this adaptive backstepping controller, an integrated PD controller which contains the perturbation force, disturbance torque and nonlinear coupling terms feed-forward is designed based on dual quaternion system equations. The theoretical analysis shows that the adaptive backstepping controller has stronger robustness to the mass and the moment of inertia uncertainty than the PD controller, and the numerical simulation verified this conclusion.Finally, an integrated sliding mode variable structure controller is designed based on dual quaternions. Then, adding the idea of model reference adaptive control theory, an adaptive sliding mode variable structure controller is derived. The Lyapunov stability of these two controller analysed. In addition, explained the adaptive sliding mode controller can better compensate for the interference terms caused by the uncertainty of mass and the moment of inertia, and thus has stronger robustness. The mathematical simulation verified the validity of these two controllers, and illustrated the adaptive sliding mode controller is more robust.