Robust constrained fault-tolerant attitude control for flexible spacecraft

Author(s):  
Haihui Long ◽  
Jiankang Zhao

In this paper, robust constrained fault-tolerant attitude controllers are proposed for flexible spacecraft subjected to external disturbance, model uncertainty, input saturation, and actuator faults. Three types of actuator faults of spacecraft, i.e. partial loss of effectiveness, stuck fault, and outage fault, are modeled explicitly. To handle these actuator faults, a significant lemma is proposed and rigorous proof is conducted at length. By introducing two e-modification parameter update laws to online estimate the unknown parameters caused by actuator faults, constrained fault-tolerant attitude controllers of flexible spacecraft are designed to accommodate these faults without the need of any prior information about these faults. The proposed controllers can achieve the disturbance attenuation in the sense of [Formula: see text] gain. The effectiveness of the proposed algorithms is assessed through numerical simulations.

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Rui-Qi Dong ◽  
Yu-Yao Wu ◽  
Ying Zhang ◽  
Ai-Guo Wu

In this paper, an observer-based adaptive backstepping attitude maneuver controller (briefly, OBABC) for flexible spacecraft is presented. First, an observer is constructed to estimate the flexible modal variables. Based on the proposed observer, a backstepping control law is presented for the case where the inertia matrix is known. Further, an adaptive law is developed to estimate the unknown parameters of the inertia matrix of the flexible spacecraft. By utilizing Lyapunov theory, the proposed OBABC law can guarantee the asymptotical convergence of the closed-loop system in the presence of the external disturbance, incorporating with the L2-gain performance criterion constraint. Simulation results show that the attitude maneuver can be achieved by the proposed observer-based adaptive backstepping attitude control law.


2021 ◽  
Author(s):  
Kang Liu ◽  
Rujing Wang

Abstract This study considers the problem of finitetime attitude control for quadrotor unmanned aerial vehicles (UAVs) subject to parametric uncertainties, external disturbances, input saturation, and actuator faults. Under the strong approximation of radial basis function neural networks (RBFNN), an adaptive finitetime NN observer is first presented to obtain the accurate information of unavailable angular velocity. More importantly, an adaptive mechanism to adjust the output gain of the fuzzy logic system (FLS) is developed to avoid the selection of larger control gains, and can even work well without the prior information on the bound of the lumped disturbance. Based on the nonsingular fast terminal sliding mode manifold, a novel switching control law is designed by incorporating the adaptive FLS and fast continuous controller in order to remove the undesired chattering phenomenon and solve the negative effects induced from the parametric uncertainty, external disturbance, and actuator fault. To deal with the input saturation, an auxiliary system is constructed. The rigorous theoretical analysis is given to prove that all the signals in the closed-loop system are uniformly bounded, and tracking errors converge into bounded neighborhoods near the origin in finite time. Moreover, the issue of selecting control parameters is analyzed in detail. Last but not least, the comparative simulation results show the validity and feasibility of the proposed control framework.


Author(s):  
Zhong-Zhe Yue ◽  
Jing-Guang Sun

This study investigates the flight longitudinal tracking control problem of hypersonic vehicle in presence of the input saturation, external disturbances, model parametric uncertainties, and actuator faults. First, the velocity and altitude subsystem are established with disturbances based on the feedback linearization model. Second, two robust anti-saturation fault-tolerant controllers are designed for the velocity subsystem and altitude subsystem by the utilization of the tangent function, Nussbaum function, and adaptive nonlinear filter. Finally, Lyapunov stability theory is used to prove that the states of the closed-loop system are bounded. And, the effectiveness and robustness of the control strategy are proved by numerical simulations.


2019 ◽  
Vol 42 (6) ◽  
pp. 1083-1096 ◽  
Author(s):  
Mohammad Reza Soltanpour ◽  
Farshad Hasanvand ◽  
Reza Hooshmand

In this paper, a gain scheduled [Formula: see text] state-feedback controller has been designed to control the attitude of a linear parameter varying (LPV) model of a quadrotor unmanned aerial vehicle (UAV). The scheduling parameters vector, which consists of some states and the control inputs, must vary in a specified polyhedron so that the affine LPV model would be analyzable; therefore, some pre-assumed constraints on states and input saturation have been taken into account in design process. The stabilization and disturbance attenuation conditions are obtained via elementary manipulations on the notion of [Formula: see text] control design. The resulting parameter dependent linear matrix inequalities are solved through a Robust LMI Parser (Rolmip) – which works jointly with YALMIP (A toolbox for modeling and optimization in MATLAB)– by transforming polynomial parameter dependent matrices into multi-simplex domain, to best deal with nonconvex problems. In the end, simulation results have been presented and compared with existing literature to examine the capability of such method in the presence and absence of wind disturbances.


Author(s):  
Peng Li ◽  
Qi Liu ◽  
Chen-Yu He ◽  
Xiao-Qing Liu

This paper investigates the three-dimensional guidance with the impact angle constraint, actuator faults and input constraint. Firstly, an adaptive three-dimensional guidance law with impact angle constraint is designed by using the terminal sliding mode control and nonhomogeneous disturbance observer. Then, in order to solve the problem of the input saturation and actuator faults, an adaptive anti-saturation fault-tolerant three-dimensional law is proposed by using the hyperbolic tangent function based on the passive fault-tolerant control. Finally, the effectiveness of the designed guidance laws is verified by using the Lyapunov function and simulation.


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