scholarly journals Active Disturbance Rejection Station-Keeping Control of Unstable Orbits around Collinear Libration Points

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Min Zhu ◽  
Hamid Reza Karimi ◽  
Hui Zhang ◽  
Qing Gao ◽  
Yong Wang

An active disturbance rejection station-keeping control scheme is derived and analyzed for station-keeping missions of spacecraft along a class of unstable periodic orbits near collinear libration points of the Sun-Earth system. It is an error driven, rather than model-based control law, essentially accounting for the independence of model accuracy and linearization. An extended state observer is designed to estimate the states in real time by setting an extended state, that is, the sum of unmodeled dynamic and external disturbance. This total disturbance is compensated by a nonlinear state error feedback controller based on the extended state observer. A nonlinear tracking differentiator is designed to obtain the velocity of the spacecraft since only position signals are available. In addition, the system contradiction between rapid response and overshoot can be effectively solved via arranging the transient process in tracking differentiator. Simulation results illustrate that the proposed method is adequate for station-keeping of unstable Halo orbits in the presence of system uncertainties, initial injection errors, solar radiation pressure, and perturbations of the eccentric nature of the Earth's orbit. It is also shown that the closed-loop control system performance is improved significantly using our method comparing with the general LQR method.

Author(s):  
Wenjie Lou ◽  
Ming Zhu ◽  
Xiao Guo

In this paper, to address the spatial trajectory tracking problem of unmanned airships, a robust controller based on active disturbance rejection control is presented. By transforming the airship model to a standardized form, a straightforward design approach is adopted for the design of the controller. Active disturbance rejection control is composed of a tracking differentiator, an extended state observer, and a nonlinear state error feedback. The proposed controller replaces the conventional tracking differentiator with a third-order differentiator. The new tracking differentiator provides higher tracking precision and smoother transient process. The external disturbances and model uncertainties are observed by the extended state observer and compensated in the controller design, subsequently. Comparisons with technologies frequently used in the trajectory tracking are made through numerical simulation. The comparisons validate that the proposed controller provides satisfying performance and robustness in the presence of model uncertainty and external disturbance.


2017 ◽  
Vol 9 (2) ◽  
pp. 168781401668903 ◽  
Author(s):  
Bingyou Liu ◽  
Yi Jin ◽  
Changan Zhu ◽  
Changzheng Chen

The pitching axis of a satellite camera is controlled under the weightless environment. A novel active disturbance rejection controller is designed to eliminate the influences of the pitching axis. The novel active disturbance rejection controller is designed based on a new nonlinear function, and thus, this function is first established. The function exhibits better continuity and smoothness than previously available functions, hence, it can effectively improve the high-frequency flutter phenomenon. Therefore, the novel active disturbance rejection controller based on the new nonlinear function can eliminate disturbances of the pitching axis. The novel active disturbance rejection controller is composed of a tracking differentiator, a novel extended state observer, and a novel nonlinear state error feedback. The tracking differentiator is used to arrange the transient process. Nonlinear dynamics, model uncertainty, and external disturbances are extended to a new state. The novel extended state observer is utilized to observe this state. The overtime variation of the system can be predicted and compensated using the novel extended state observer. The novel nonlinear state error feedback is adopted to restrain the residual errors of the system. Finally, simulation experiments are performed, and results show that the novel active disturbance rejection controller exhibits better performance than the traditional active disturbance rejection controller.


Author(s):  
Jingxin Dou ◽  
Xiangxi Kong ◽  
Bangchun Wen

This paper presents a new active disturbance rejection controller to solve the altitude and attitude control problem for a quadrotor unmanned aerial vehicle. The proposed method requires only the output information of the system. Using the pitch subsystem as an example, the proposed controller is designed by using dynamic surface control strategy incorporated with tracking differentiator, and extended state observer, which is used to estimate the uncertain disturbance. The estimate states of extended state observer are used to design the dynamic surface control law for altitude and attitude tracking problem of the quadrotor unmanned aerial vehicle. The stability analysis proves that a sufficient condition of the asymptotic stability of the extended state observer is achieved, the asymptotic stability of the closed-loop system can be guaranteed, and the tracking feedback error can made arbitrarily small by adjusting the controller parameters. Several simulation results are presented to corroborate that the proposed control method has better effectiveness and robustness.


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