scholarly journals Composite Antidisturbance Control for a Class of Nonlinear Stochastic Systems via Disturbance Observer

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yunlong Liu ◽  
Yumin Zhang ◽  
Xiuming Yao
Keyword(s):  
Disturbance Observer ◽  
Stochastic Systems ◽  
Control Method ◽  
The Other ◽  
Stabilization Problem ◽  
Nonlinear Stochastic Systems ◽  
Stochastic Disturbance ◽  
Harmonic Signals ◽  
Unknown Phase ◽  
Dynamic Performances

The stabilization problem is investigated in this paper for a class of nonlinear systems with disturbances. The disturbances are supposed to be classified into two types. One type in the input channel is generated by an exogenous system, which can represent the constant or harmonic signals with unknown phase and magnitude. The other type is stochastic disturbance. Two kinds of nonlinear dynamics in the plants are considered, respectively, which correspond to the known and unknown functions. By integrating the disturbance observers with conventional control method, the first type of disturbances can be estimated and rejected. Simultaneously, the desired dynamic performances can be guaranteed. An example is given to show the effectiveness of the proposed scheme.

Composite hierarchical anti-disturbance control for stochastic systems with multiple disturbances

2017 ◽  
Vol 40 (6) ◽  
pp. 1950-1955 ◽  
Author(s):  
Shixiang Sun ◽  
Xinjiang Wei ◽  
Huifeng Zhang
Keyword(s):  
Disturbance Observer ◽  
Closed Loop ◽  
Stochastic Systems ◽  
Time Derivative ◽  
Closed Loop System ◽  
Stochastic Disturbance ◽  
Multiple Disturbances ◽  
Control Scheme ◽  
Bounded Disturbance ◽  
White Noises

A class of stochastic systems with multiple disturbances, which includes white noises and disturbances whose time derivative is bounded, is considered in this paper. To estimate the unknown bounded disturbance, a stochastic disturbance observer is proposed. Based on the observer, a disturbance observer-based disturbance control scheme is constructed such that the composite closed-loop system is asymptotically bounded. Finally, a simulation example is given to demonstrate the feasibility and effectiveness of the proposed scheme.

scholarly journals A Covariance Feedback Approach to Covariance Control of Nonlinear Stochastic Systems

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Salman Baroumand ◽  
Amir Reza Zaman ◽  
Mohammad Reza Mahmoudi
Keyword(s):  
Nonlinear Systems ◽  
Linear Approximation ◽  
Feedback Linearization ◽  
Control Algorithm ◽  
Stochastic Systems ◽  
Control Method ◽  
Nonlinear Case ◽  
Nonlinear Stochastic Systems ◽  
Covariance Control ◽  
Feedback Algorithm

In this paper, the covariance control algorithm for nonlinear stochastic systems using covariance feedback is studied. Covariance control of nonlinear systems scenario involves the theory of covariance control based on the idea of the covariance feedback. Therefore, the proposed covariance control algorithm is derived for our case, firstly by applying the covariance control method and linear approximation of nonlinear systems, and then it is achieved by adopting this method for a class of nonlinear stochastic systems by using feedback linearization idea and a covariance feedback controller. The effectiveness of the proposed covariance feedback algorithm is studied using numerous simulations concerning different nonlinear case studies.

Robust finite-time trajectory tracking control for a space manipulator with parametric uncertainties and external disturbances

2021 ◽  
pp. 095441002110147
Author(s):  
Qijia Yao
Keyword(s):  
Trajectory Tracking ◽  
Finite Time ◽  
Tracking Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Parametric Uncertainties ◽  
External Disturbances ◽  
Trajectory Tracking Control ◽  
Space Manipulator ◽  
Tracking Controller

Space manipulator is considered as one of the most promising technologies for future space activities owing to its important role in various on-orbit serving missions. In this study, a robust finite-time tracking control method is proposed for the rapid and accurate trajectory tracking control of an attitude-controlled free-flying space manipulator in the presence of parametric uncertainties and external disturbances. First, a baseline finite-time tracking controller is designed to track the desired position of the space manipulator based on the homogeneous method. Then, a finite-time disturbance observer is designed to accurately estimate the lumped uncertainties. Finally, a robust finite-time tracking controller is developed by integrating the baseline finite-time tracking controller with the finite-time disturbance observer. Rigorous theoretical analysis for the global finite-time stability of the whole closed-loop system is provided. The proposed robust finite-time tracking controller has a relatively simple structure and can guarantee the position and velocity tracking errors converge to zero in finite time even subject to lumped uncertainties. To the best of the authors’ knowledge, there are really limited existing controllers can achieve such excellent performance under the same conditions. Numerical simulations illustrate the effectiveness and superiority of the proposed control method.

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