In this paper,the authors address the attitude regulation problem of uncertain flexible spacecraft with unknown control directions and input disturbances.The major challenges of the problem include the concurrence of ...In this paper,the authors address the attitude regulation problem of uncertain flexible spacecraft with unknown control directions and input disturbances.The major challenges of the problem include the concurrence of the unknown actuation sign and the unknown parameters in both the plant and the external disturbances,along with the impact of vibrations from flexible appendages.To overcome these challenges,the authors transform the conventional mathematical model of a flexible spacecraft to a multivariable strict-feedback normal form and adopt a systematic approach within the framework of nonlinear output regulation.To solve the attitude regulation and disturbance rejection problem,the authors introduce a nonlinear internal model candidate to convert the problem into a stabilization problem for an augmented system.Then,a Nussbaum function-based stabilizer is designed to handle unknown control directions and complete the design.Simulation results are provided to show the effectiveness of the proposed controller.展开更多
This paper studies global robust tracking of uncertain Euler-Lagrange systems with input disturbances.The authors develop a robust regulation-based approach for the problem.Specifically,by introducing a novel nonlinea...This paper studies global robust tracking of uncertain Euler-Lagrange systems with input disturbances.The authors develop a robust regulation-based approach for the problem.Specifically,by introducing a novel nonlinear internal model,the authors solve global asymptotic trajectory tracking with disturbance rejection of multiple step/sinusoidal signals with unknown amplitudes,frequencies,and phases.Moreover,the authors show that a robustness property to actuator noises can be guaranteed in a sense of strong integral input-to-state stability(iISS).That is,the closed-loop system is not only i ISS but also input-to-state stable(ISS)to small magnitude actuator noises.Furthermore,the authors explore a by-product overparametrized linear regression estimation,coming up with robust estimation of the unknown parameters.Finally,the authors present several numerical examples to illustrate the theoretical results.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.62073168。
文摘In this paper,the authors address the attitude regulation problem of uncertain flexible spacecraft with unknown control directions and input disturbances.The major challenges of the problem include the concurrence of the unknown actuation sign and the unknown parameters in both the plant and the external disturbances,along with the impact of vibrations from flexible appendages.To overcome these challenges,the authors transform the conventional mathematical model of a flexible spacecraft to a multivariable strict-feedback normal form and adopt a systematic approach within the framework of nonlinear output regulation.To solve the attitude regulation and disturbance rejection problem,the authors introduce a nonlinear internal model candidate to convert the problem into a stabilization problem for an augmented system.Then,a Nussbaum function-based stabilizer is designed to handle unknown control directions and complete the design.Simulation results are provided to show the effectiveness of the proposed controller.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.61673216 and 62073168supported by the China Scholarship Council on his study at the University of Groningen,The Netherlandspartially done when he was with the School of Automation,Nanjing University of Science and Technology,Nanjing 210094,China。
文摘This paper studies global robust tracking of uncertain Euler-Lagrange systems with input disturbances.The authors develop a robust regulation-based approach for the problem.Specifically,by introducing a novel nonlinear internal model,the authors solve global asymptotic trajectory tracking with disturbance rejection of multiple step/sinusoidal signals with unknown amplitudes,frequencies,and phases.Moreover,the authors show that a robustness property to actuator noises can be guaranteed in a sense of strong integral input-to-state stability(iISS).That is,the closed-loop system is not only i ISS but also input-to-state stable(ISS)to small magnitude actuator noises.Furthermore,the authors explore a by-product overparametrized linear regression estimation,coming up with robust estimation of the unknown parameters.Finally,the authors present several numerical examples to illustrate the theoretical results.
