Attitude and orbit coupled control and simulation of spacecraft formation by using intelligent adaptive control based on characteristic model
Regarding to the relative attitude and orbit of spacecraft formation flying, a nonlinear dynamic model of six degree of freedom coupled with attitude and orbits established, with the help of characteristic model, this paper mainly analyzes the factors of the spatial perturbation and multiple disturbance torques, a kind of intelligent adaptive controller is designed based on the combination of RBF neural network and the golden section adaptive control. Later, the simulation platform Jade is used to simulate and analyze the Multi-Agent system of spacecraft formation. The results show that the spacecraft formation can run along in the ideal orbit, the effect of the control system has good robustness, fault tolerance and intelligence.
On fractional order composite model reference adaptive control
This paper presents a novel composite model reference adaptive control approach for a class of fractional order linear systems with unknown constant parameters. The method is extended from the model reference adaptive control. The parameter estimation error of our method depends on both the tracking error and the prediction error, whereas the existing method only depends on the tracking error, which makes our method has better transient performance in the sense of generating smooth system output. By the aid of the continuous frequency distributed model, stability of the proposed approach is established in the Lyapunov sense. Furthermore, the convergence property of the model parameters estimation is presented, on the premise that the closed-loop control system is stable. Finally, numerical simulation examples are given to demonstrate the effectiveness of the proposed schemes.
Study of pointing maneuvers for a spacecraft virtual structure formation
This paper describes a complex virtual simulation of three spacecraft in tight formation. Using rotational kinematics and rigid body dynamics, the virtual spacecraft structure is designed to perform calculated and synchronized maneuvers to point the formation in a desired direction. Modern control theories are applied to maintain the integrity of the tight formation and minimize errors as the entire system reorients to tracks the target object with its virtual boresight. This process involves determining the required independent orientation (Eulerian) angles using the target vector coordinates with respect to the initial orientation of the formation