Adaptive nonlinear disturbance observer-based control for stochastic systems with multiple heterogeneous disturbances

2020 ◽  
Vol 42 (11) ◽  
pp. 2020-2030
Author(s):  
Xinqing Li ◽  
Xinjiang Wei ◽  
Huifeng Zhang ◽  
Jian Han ◽  
Xin Hu ◽  
...  
Keyword(s):  
Disturbance Observer ◽  
Composite System ◽  
Stochastic Systems ◽  
Nonlinear Function ◽  
Control Input ◽  
System State ◽  
Nonlinear Disturbance Observer ◽  
Nonlinear Disturbance ◽  
Nonlinear Signal ◽  
And Control

The problem of anti-disturbance control is studied for a class of stochastic systems with multiple heterogeneous disturbances, which include three kinds of disturbance. One is the non-harmonic disturbance coupled with system state and control input. The other one is an unexpected nonlinear signal described as a nonlinear function. The third one is white noise. An adaptive nonlinear disturbance observer (ANDO) is constructed to estimate non-harmonic disturbance. Based on which, a new adaptive nonlinear disturbance observer-based control (ANDOBC) strategy is developed such that the composite system is asymptotically bounded in mean square. Simulation results are given to show its effectiveness of the proposed method.

Nonlinear disturbance observer-based control for a class of discrete-time stochastic systems with multiple heterogenous disturbances

2019 ◽  
Vol 42 (2) ◽  
pp. 180-187
Author(s):  
Hanxu Zhao ◽  
Xinjiang Wei ◽  
Huifeng Zhang ◽  
Hamid Reza Karimi
Keyword(s):  
Discrete Time ◽  
Disturbance Observer ◽  
Composite System ◽  
Stochastic Systems ◽  
Mean Square ◽  
Random Vectors ◽  
Nonlinear Disturbance Observer ◽  
Nonlinear Disturbance ◽  
Simulation Results

In this paper, the nonlinear disturbance observer-based control (NDOBC) scheme is proposed for a class of discrete-time stochastic systems with multiple heterogenous disturbances, which include the non-harmonic disturbance and a sequence of random vectors. A nonlinear disturbance observer (NDO) is designed to estimate the non-harmonic disturbance, then the NDOBC scheme is proposed by combining DOBC with [Formula: see text] control, such that the composite system can achieves asymptotically mean-square bounded and asymptotically mean-square stable in different conditions. Finally, simulation results show the effectiveness of the proposed method.

Elegant anti-disturbance control for stochastic systems with multiple heterogeneous disturbances based on fuzzy logic systems

2020 ◽  
Vol 42 (14) ◽  
pp. 2611-2621
Author(s):  
Lihong You ◽  
Xinjiang Wei ◽  
Jian Han ◽  
Huifeng Zhang ◽  
Xiuhua Liu ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Disturbance Observer ◽  
Composite System ◽  
Stochastic Systems ◽  
Nonlinear Function ◽  
Fuzzy Logic Systems ◽  
Logic Systems ◽  
State Responses ◽  
Unknown Nonlinear Dynamics ◽  
Control Accuracy

There are a large number of non-harmonic disturbances generated by nonlinear exogenous systems in realistic engineering. The current disturbance observer is not applicable for estimating the non-harmonic disturbance with unknown nonlinear dynamics, thus greatly reducing the accuracy of the controller. This paper addresses a class of stochastic systems with multiple heterogeneous disturbances including white noise and non-harmonic disturbance with unknown smooth nonlinear function, which can be approximated by fuzzy logic systems. Based on the approximation of the unknown nonlinear function, an adaptive disturbance observer (ADO) is constructed to estimate non-harmonic disturbance. Combining disturbance observer-based control with fuzzy control, an elegant anti-disturbance control (EADC) scheme is proposed such that the composite system achieves asymptotically bounded in mean square. Simulation examples show that the state responses of the system gradually approache [Formula: see text] from divergence, indicating that the effectiveness of the controller is satisfactory. In addition, the anti-disturbance control accuracy of EADC approximately improves [Formula: see text] times compared with [Formula: see text] control. The simulation results demonstrate the feasibility and effectiveness of the proposed scheme.

Adaptive sliding mode control for asymptotic stabilization of underactuated mechanical systems via higher-order nonlinear disturbance observer

2019 ◽  
Vol 25 (17) ◽  
pp. 2340-2350 ◽  
Author(s):  
Kakoli Majumder ◽  
B. M. Patre
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Mechanical Systems ◽  
Higher Order ◽  
Adaptive Sliding Mode Control ◽  
Control Input ◽  
Underactuated Mechanical Systems ◽  
Nonlinear Disturbance Observer ◽  
Nonlinear Disturbance

The development of a nonlinear controller of stabilization of underactuated mechanical systems (UMSs) is a challenging endeavor due to a larger number of output variables to be controlled than the control input space. This paper proposes an adaptive sliding mode control based on a higher-order nonlinear disturbance observer (HONDO) for stabilizing the rotational pendulum (RP) system falling under the class of UMSs. Firstly, the HONDO is designed in such a way that it can improve accuracy in estimations with its incremental order. As a result, the proposed controller obtained from the sliding surface which is developed with system’s states and estimations, forces the states attaining the sliding mode and hence keeps them to their origin forever against disturbances. To achieve this, the sliding coefficients are obtained using inertia matrix of the system. The zero dynamics is stabilized by the proposed controller. This alleviates the chattering problem in the control input. Finally, numerical performance on the underactuated RP model is analyzed to show the efficiency of the proposed controller and it is compared with the established control technique found in the literature.

Anti-disturbance control based on nonlinear disturbance observer for a class of stochastic systems

2018 ◽  
Vol 41 (6) ◽  
pp. 1665-1675 ◽  
Author(s):  
Lewei Dong ◽  
Xinjiang Wei ◽  
Huifeng Zhang
Keyword(s):  
Disturbance Observer ◽  
Stochastic Systems ◽  
Disturbance Attenuation ◽  
Nonlinear Disturbance Observer ◽  
Disturbance Dynamics ◽  
Active Disturbance Rejection ◽  
Disturbance Rejection Control ◽  
Nonlinear Disturbance ◽  
Linear Disturbance ◽  
State Responses

In engineering, there exist lots of nonlinear disturbance dynamics, which can be described by nonlinear exogenous systems. The current stochastic linear disturbance observer is conservative and is not applicable for nonlinear disturbance dynamics. This paper studies a class of stochastic systems with multiple disturbances, including white noise and disturbances modelled by a nonlinear exogenous system. To estimate the disturbance with nonlinear dynamics, a stochastic nonlinear disturbance observer is proposed. Based on the observer, a nonlinear disturbance observer-based disturbance attenuation control (NDOBDAC) scheme is constructed such that the composite closed-loop system is asymptotically mean-square bounded. According to the simulation example, the state responses of the system diverge in the absence of control, but it tends to be [Formula: see text] under NDOBDAC, which demonstrates the effectiveness of the proposed scheme. In addition, the anti-disturbance control accuracy of NDOBDAC approximately improves [Formula: see text] times compared with [Formula: see text] control and active disturbance rejection control (ADRC). The simulation results demonstrate the feasibility and effectiveness of the proposed scheme.

Nonlinear Disturbance Observer Based Impedance Control for a Teleoperation System Under Time Delay

2009 ◽  
Author(s):  
A. Monemian Esfahani ◽  
S. M. Rezaei ◽  
M. Zareinejad
Keyword(s):  
Time Delay ◽  
Disturbance Observer ◽  
Impedance Control ◽  
Fixed Time ◽  
Design Parameters ◽  
Control Input ◽  
Nonlinear Disturbance Observer ◽  
Teleoperation System ◽  
Nonlinear Disturbance ◽  
The Stability

In this paper a nonlinear disturbance observer (NDO) based impedance control is proposed for a teleoperation system. The unknown friction and uncertainties will be estimated by the observer and added to the control input for compensation. Although friction will improve the stability, it worsens the transparency of the system which is another major point in teleoperation systems. The stability of the system is guaranteed by Lyapunov stability criterion and selecting the best design parameters. Tracking of force/position is achieved by these parameters. Also a fixed time delay is added to the system because of delays in the cables and other sources, it is then compensated with the designed controller. Performance of the proposed control is validated by experimental results.

scholarly journals Aerodynamic analysis and control for a novel coaxial ducted fan aerial robot in ground effect

2020 ◽  
Vol 17 (4) ◽  
pp. 172988142095302
Author(s):  
Tianfu Ai ◽  
Bin Xu ◽  
Changle Xiang ◽  
Wei Fan ◽  
Yibo Zhang
Keyword(s):  
Disturbance Observer ◽  
Ground Effect ◽  
System Stability ◽  
Bench Test ◽  
Nonlinear Disturbance Observer ◽  
Modeling And Control ◽  
Ducted Fan ◽  
Aerial Robot ◽  
Nonlinear Disturbance ◽  
And Control

Modeling and control for a novel coaxial ducted fan aerial robot in-ground-effect is presented in this article. Based on experiments using the ducted fan bench test, the fitting curve of the ground effect thrust of the ducted fan aerial robot at different heights is obtained. In addition, the flow field simulation results of the prototype with ground effect at different heights can be obtained using computational fluid dynamics software. A simplified model of the prototype for control can be designed based on several reasonable hypotheses that are established using blade element and momentum theory. To compensate for the disturbance associated with ground effect, a nonlinear disturbance observer is designed to estimate the disturbance, and control structure of the closed-loop system is composed of a nonlinear disturbance observer combined with a double-loop proportion–integration–differentiation controller. The results of several numerical simulations and experiments demonstrate the effectiveness of this controller structure. The performances of tracking trajectory and system stability are improved significantly, compared to the situation that the ground effect is not compensated for.

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

2019 ◽  
Vol 41 (15) ◽  
pp. 4398-4408
Author(s):  
Yongli Wei ◽  
Xinjiang Wei ◽  
Huifeng Zhang ◽  
Jian Han
Keyword(s):  
Neural Network ◽  
Lyapunov Function ◽  
Linear Matrix Inequality ◽  
Disturbance Observer ◽  
Composite System ◽  
Stochastic Systems ◽  
Dynamic Performance ◽  
Nonlinear Function ◽  
Linear Matrix ◽  
Matrix Inequality

This paper studies the problem of anti-disturbance control for a class of stochastic systems with multiple heterogeneous disturbances, which include the white noise and the non-harmonic disturbance with unknown nonlinear function. An adaptive disturbance observer is constructed to estimate the non-harmonic disturbances with unknown nonlinear function, which is approximated by neural network. A composite hierarchical anti-disturbance control (CHADC) scheme is designed by integrated Lyapunov function and linear matrix inequality (LMI), such that the expected dynamic performance of the composite system is achieved. Finally, simulations show that the approach is proper and effective.

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