Designing a backstepping sliding mode controller for an assistant human knee exoskeleton based on nonlinear disturbance observer

Mechatronics ◽  
2018 ◽  
Vol 54 ◽  
pp. 121-132 ◽  
Author(s):  
M. Khamar ◽  
M. Edrisi
Keyword(s):  
Disturbance Observer ◽  
Sliding Mode ◽  
Sliding Mode Controller ◽  
Nonlinear Disturbance Observer ◽  
Human Knee ◽  
Nonlinear Disturbance

scholarly journals Terminal Sliding Mode Control of Mobile Wheeled Inverted Pendulum System with Nonlinear Disturbance Observer

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
SongHyok Ri ◽  
Jian Huang ◽  
Yongji Wang ◽  
MyongHo Kim ◽  
Sonchol An
Keyword(s):  
Disturbance Observer ◽  
Inverted Pendulum ◽  
Sliding Mode ◽  
Sliding Mode Controller ◽  
Terminal Sliding Mode ◽  
Pendulum System ◽  
Nonlinear Disturbance Observer ◽  
Inverted Pendulum System ◽  
Wheeled Inverted Pendulum ◽  
Nonlinear Disturbance

A terminal sliding mode controller with nonlinear disturbance observer is investigated to control mobile wheeled inverted pendulum system. In order to eliminate the main drawback of the sliding mode control, “chattering” phenomenon, and for compensation of the model uncertainties and external disturbance, we designed a nonlinear disturbance observer of the mobile wheeled inverted pendulum system. Based on the nonlinear disturbance observer, a terminal sliding mode controller is also proposed. The stability of the closed-loop mobile wheeled inverted pendulum system is proved by Lyapunov theorem. Simulation results show that the terminal sliding mode controller with nonlinear disturbance observer can eliminate the “chattering” phenomenon, improve the control precision, and suppress the effects of external disturbance and model uncertainties effectively.

An Intelligence Sliding Mode Controller Based on Nonlinear Disturbance Observer for Rotary Steering Drilling Stabilized Platform

2013 ◽  
Vol 341-342 ◽  
pp. 913-919
Author(s):  
Yuan Tao Zhang ◽  
Jun Yi
Keyword(s):  
Disturbance Observer ◽  
Sliding Mode ◽  
Design Parameters ◽  
Sliding Mode Controller ◽  
Sigmoid Function ◽  
Nonlinear Disturbance Observer ◽  
Function Coefficient ◽  
Nonlinear Disturbance ◽  
Stabilized Platform ◽  
Uncertain Disturbance

An intelligence sliding mode controller for rotary steering drilling stabilized platform based on nonlinear disturbance observer is presented. Nonlinear disturbance observer which can converge exponentially with suitable design parameters is used to obs erve the uncertain disturbance of stabilized platform under work condition. Sliding mode controller is designed to guarantee the robustness of the closed-loop system. The adaptive rate of switching gain is designed and sign function is replaced by bipolar sigmoid function to weaken chattering. Finally, genetic algorithm is applied to search the optimal controller parameters, including switching function coefficient, switching gain adaptive coefficient, sigmoid function coefficient and observer coefficient. Simulation results show that nonlinear disturbance observer can observe the uncertain disturbance effectively, controller output is decreased and stabilized platform can get optimal control performance and robustness.

scholarly journals Position Tracking Control of Robotic System Subject to Matched and Mismatched Disturbances

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xia Liu ◽  
Dandan Liu ◽  
Hao Sheng
Keyword(s):  
Disturbance Observer ◽  
Sliding Mode ◽  
Robotic System ◽  
Position Tracking ◽  
Sliding Mode Controller ◽  
Nonlinear Disturbance Observer ◽  
Mismatched Disturbance ◽  
Position Tracking Control ◽  
Nonlinear Disturbance ◽  
Mismatched Disturbances

For nonlinear coupled robotic system subject to matched and mismatched disturbances, this paper designs an adaptive disturbance observer-based exponential sliding mode controller to achieve position tracking. Firstly, matched disturbance, mismatched disturbance, and the derivative of mismatched disturbance are defined as the lumped disturbance in robotic system. Secondly, a nonlinear disturbance observer is constructed to estimate the lumped disturbance, and an adaptive law is proposed to estimate the bound of the lumped disturbance. Finally, an exponential sliding mode controller is derived by combining the nonlinear disturbance observer and exponential convergence law. Stability and tracking performance of the robotic system is analyzed via Lyapunov function approach. Simulation results show that, with the proposed approach, both matched and mismatched disturbances in robotic system can be effectively depressed while achieving position tracking.

scholarly journals Sliding Mode Control for Diesel Engine Air Path Subject to Matched and Unmatched Disturbances Using Extended State Observer

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Sofiane Ahmed Ali ◽  
Nicolas Langlois
Keyword(s):  
Diesel Engine ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Sliding Mode Controller ◽  
Nonlinear Disturbance Observer ◽  
Engine Model ◽  
Disturbance Estimation ◽  
Path System ◽  
Nonlinear Disturbance ◽  
Nominal Performance

The paper develops a sliding mode controller via nonlinear disturbance observer for diesel engine air path system subject to matched and unmatched disturbances. The proposed controller is based upon a novel nonlinear disturbance observer (NDO) structure which uses the concept of total disturbance estimation in order to estimate simultaneously the matched and the unmatched disturbances in the system. This estimation is then incorporated in a composite controller which alleviates the chattering problem and maintains the nominal performance of the system in the absence of disturbances. Simulations results of the proposed controller on a recently validated experimental air path diesel engine model show that the proposed methods exhibit a better performances comparing to the baseline SMC in terms of reducing chattering and nominal performances recovery.

scholarly journals Adaptive Backstepping Sliding Mode Control of the Hybrid Conveying Mechanism with Mismatched Disturbances via Nonlinear Disturbance Observers

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Wei Yuan ◽  
Guoqin Gao ◽  
Jianzhen Li
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Sliding Mode Controller ◽  
Adaptive Backstepping ◽  
Nonlinear Disturbance Observer ◽  
Control Scheme ◽  
Backstepping Sliding Mode Control ◽  
Nonlinear Disturbance ◽  
Mismatched Disturbances

An adaptive backstepping sliding mode controller combined with a nonlinear disturbance observer is designed for trajectory tracking of the electrically driven hybrid conveying mechanism with mismatched disturbances. A nonlinear disturbance observer is constructed for estimation and compensation of the mismatched and matched disturbances. Then, a hybrid control scheme is designed by combining the adaptive backstepping sliding mode controller and the mentioned observer. The Lyapunov candidate functions are utilized to derive the control and adaptive law. According to the simulation and experimental results, superior tracking performance could be obtained through the presented control scheme compared with conventional backstepping sliding mode control. Meanwhile, the presented control scheme can effectively reduce the chattering problem and improve tracking precision.

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