Adaptive robust H∞, control for nonlinear systems with parametric uncertainties and external disturbances

2003 ◽  
Author(s):  
Min Wu ◽  
Lingbo Zhang ◽  
Guoping Liu
Keyword(s):  
Nonlinear Systems ◽  
Parametric Uncertainties ◽  
External Disturbances

scholarly journals Control of an IPMC Soft Actuator Using Adaptive Full-Order Recursive Terminal Sliding Mode

Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 33
Author(s):  
Romina Zarrabi Ekbatani ◽  
Ke Shao ◽  
Jasim Khawwaf ◽  
Hai Wang ◽  
Jinchuan Zheng ◽  
...  
Keyword(s):  
Sliding Mode ◽  
External Disturbance ◽  
Tracking Error ◽  
Working Environment ◽  
Parametric Uncertainties ◽  
Metal Composite ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Positioning Accuracy ◽  
Soft Actuator

The ionic polymer metal composite (IPMC) actuator is a kind of soft actuator that can work for underwater applications. However, IPMC actuator control suffers from high nonlinearity due to the existence of inherent creep and hysteresis phenomena. Furthermore, for underwater applications, they are highly exposed to parametric uncertainties and external disturbances due to the inherent characteristics and working environment. Those factors significantly affect the positioning accuracy and reliability of IPMC actuators. Hence, feedback control techniques are vital in the control of IPMC actuators for suppressing the system uncertainty and external disturbance. In this paper, for the first time an adaptive full-order recursive terminal sliding-mode (AFORTSM) controller is proposed for the IPMC actuator to enhance the positioning accuracy and robustness against parametric uncertainties and external disturbances. The proposed controller incorporates an adaptive algorithm with terminal sliding mode method to release the need for any prerequisite bound of the disturbance. In addition, stability analysis proves that it can guarantee the tracking error to converge to zero in finite time in the presence of uncertainty and disturbance. Experiments are carried out on the IPMC actuator to verify the practical effectiveness of the AFORTSM controller in comparison with a conventional nonsingular terminal sliding mode (NTSM) controller in terms of smaller tracking error and faster disturbance rejection.

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.

scholarly journals A Coefficient Diagram Method Controller with Backstepping Methodology for Robotic Manipulators

2015 ◽  
Vol 66 (5) ◽  
pp. 270-276 ◽  
Author(s):  
Fouad Haouari ◽  
Bali Nourdine ◽  
Mohamed Segir Boucherit ◽  
Mohamed Tadjine
Keyword(s):  
Robotic Manipulators ◽  
Control Law ◽  
Control Procedure ◽  
Parametric Uncertainties ◽  
The Novel ◽  
External Disturbances ◽  
Diagram Method ◽  
Coefficient Diagram Method ◽  
Backstepping Controller ◽  
Puma Robot

AbstractA new robust control procedure for robot manipulators is proposed in this paper. Coefficients diagram method controllers CDM and Backstepping methodology are combined to create the novel control law. Two steps of backstepping on the resulting system are used to design a nonlinear CDM-Backstepping controller. Simulations on a PUMA robot including external disturbances, parametric uncertainties and noises are performed to show the effectiveness and feasibility of the proposed method.

scholarly journals Nonlinear Adaptive Control for Wind Turbine Under Wind Speed Variation

2018 ◽  
Vol 7 (2) ◽  
pp. 87
Author(s):  
Abdelhaq.Amar Bensaber ◽  
Mustapha Benghanem ◽  
Mohammed.Amar Bensaber ◽  
Abdelmadjid. Guerouad
Keyword(s):  
Adaptive Control ◽  
Electrical Power ◽  
Adaptation Strategy ◽  
Parametric Uncertainties ◽  
System Operation ◽  
External Disturbances ◽  
Good Efficiency ◽  
Power System Operation ◽  
Nonlinear Adaptive Control ◽  
Interesting Solution

<span>Wind turbines components work as nonlinear systems where electromechanical parameters change frequently [1], which makes nonlinear control an interesting solution to prevail good efficiency. SMC has been largely used in electrical power applications because it offers interesting features like robustness to parametric uncertainties and external disturbances, to conquer the biggest drawback of the SMC, adaptation strategy consists on updating the sliding gain and the turbine torque to contribute with some important characteristics such as chatter-free performance, heftiness, robustness and secure power system operation. Matlab tests are introduced and compared.</span>

scholarly journals Finite-Time Path Following Control of an Underactuated Marine Surface Vessel with Input and Output Constraints

2020 ◽  
Vol 10 (18) ◽  
pp. 6447
Author(s):  
Mingyu Fu ◽  
Lulu Wang
Keyword(s):  
Finite Time ◽  
Input Saturation ◽  
Path Following ◽  
Parametric Uncertainties ◽  
External Disturbances ◽  
Time Path ◽  
Path Following Control ◽  
Control Scheme ◽  
Marine Surface ◽  
Surface Vessel

This paper develops a finite-time path following control scheme for an underactuated marine surface vessel (MSV) with external disturbances, model parametric uncertainties, position constraint and input saturation. Initially, based on the time-varying barrier Lyapunov function (BLF), the finite-time line-of-sight (FT-LOS) guidance law is proposed to obtain the desired yaw angle and simultaneously constrain the position error of the underactuated MSV. Furthermore, the finite-time path following constraint controllers are designed to achieve tracking control in finite time. Additionally, considering the model parametric uncertainties and external disturbances, the finite-time disturbance observers are proposed to estimate the compound disturbance. For the sake of avoiding the input saturation and satisfying the requirements of finite-time convergence, the finite-time input saturation compensators were designed. The stability analysis shows that the proposed finite-time path following control scheme can strictly guarantee the constraint requirements of the position, and all error signals of the whole control system can converge into a small neighborhood around zero in finite time. Finally, comparative simulation results show the effectiveness and superiority of the proposed finite-time path following control scheme.

Event-triggered tracking control for nonlinear systems subject to time-varying external disturbances

Automatica ◽  
2020 ◽  
Vol 119 ◽  
pp. 109070
Author(s):  
Ting Li ◽  
Changyun Wen ◽  
Jun Yang ◽  
Shihua Li ◽  
Lei Guo
Keyword(s):  
Nonlinear Systems ◽  
Tracking Control ◽  
Time Varying ◽  
External Disturbances ◽  
Event Triggered
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