scholarly journals Fast Fractional-Order Terminal Sliding Mode Control for Seven-Axis Robot Manipulator

2020 ◽  
Vol 10 (21) ◽  
pp. 7757
Author(s):  
Jie Wang ◽  
Min Cheol Lee ◽  
Jae Hyung Kim ◽  
Hyun Hee Kim
Keyword(s):  
Sliding Mode Control ◽  
Fractional Order ◽  
Sliding Mode ◽  
Robot Manipulator ◽  
Order Derivative ◽  
Terminal Sliding Mode Control ◽  
Sliding Surface ◽  
Terminal Sliding Mode ◽  
Surface Design ◽  
Fractional Order Derivative

This paper proposes a novel controller, fast fractional-order terminal sliding mode control (FFOTSMC), for a seven-degree-of-freedom (7-DOF) robot manipulator with tracking control. The new controller applies the fractional-order derivative on both the sliding surface design and the sliding control/reaching law. Compared to previous research, which only applies the fractional-order derivative on the sliding surface design, the proposed controller has a faster convergence for reaching the sliding surface and maintaining stay on it because of the new fractional-order control law, which helps the tracking accuracy. To implement the controller on the robot with less chattering, a sliding perturbation observer (SPO) is used to estimate the disturbance and uncertainties. Stability analysis is analyzed using Lyapunov functions for fractional-order systems. The controller performance is evaluated by a simulation of a single-input and single-output (SISO) system in MATLAB Simulink and experiments on the robot manipulator.

scholarly journals Influence of Control Strategy in Risk Mitigation of Building Damage Due to Earthquake

2021 ◽  
Author(s):  
Normaisharah Mamat ◽  
Mohd Fauzi Othman ◽  
Mohd Fitri Mohd Yakub
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
Structural Integrity ◽  
Sliding Mode ◽  
Terminal Sliding Mode Control ◽  
Building Structures ◽  
Sliding Surface ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Nonsingular Terminal Sliding Mode

Abstract Building structures are prone to damage due to natural disasters, and this challenges structural engineers to design safer and more robust building structures. This study is conducted to prevent these consequences by implementing a control strategy that can enhance a building's stability and reduce the risk of damage. Therefore, to realize the structural integrity of a building, a hybrid control device is equipped with control strategies to enhance robustness. The control strategy proposed in this study is adaptive nonsingular terminal sliding mode control (ANTSMC). ANTSMC is an integrated controller of radial basis function neural network (RBFNN) and nonsingular terminal sliding mode control (NTSMC), which has a fast dynamic response, finite-time convergence, and the ability to enhance the control performance against a considerable uncertainty. The proposed controller is designed based on the sliding surface and the control law. The building with a two-degree-of-freedom (DOF) system is designed in Matlab/Simulink and validated with the experimental work connected to the LMSTest.Lab software. The performance of this controller is compared with those of the terminal sliding mode control (TSMC) and NTSMC in terms of the displacement response, sliding surface, and the probability of damage. The result showed that the proposed controller, ANTSMC can suppress vibrations up to 46%, and its percentage probability of complete damage is 15% from the uncontrolled structure. Thus, these findings are imperative towards increasing the safety level in building structures and occupants, and reducing damage costs in the event of a disaster.

Fractional-order nonsingular terminal sliding mode control via a disturbance observer for a class of nonlinear systems with mismatched disturbances

2020 ◽  
pp. 107754632092526
Author(s):  
Amir Razzaghian ◽  
Reihaneh Kardehi Moghaddam ◽  
Naser Pariz
Keyword(s):  
Nonlinear Systems ◽  
Sliding Mode Control ◽  
Fractional Order ◽  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Sliding Mode Controller ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode

This study investigates a novel fractional-order nonsingular terminal sliding mode controller via a finite-time disturbance observer for a class of mismatched uncertain nonlinear systems. For this purpose, a finite-time disturbance observer–based fractional-order nonsingular terminal sliding surface is proposed, and the corresponding control law is designed using the Lyapunov stability theory to satisfy the sliding condition in finite time. The proposed fractional-order nonsingular terminal sliding mode control based on a finite-time disturbance observer exhibits better control performance; guarantees finite-time convergence, robust stability of the closed-loop system, and mismatched disturbance rejection; and alleviates the chattering problem. Finally, the effectiveness of the proposed fractional-order robust controller is illustrated via simulation results of both the numerical and application examples which are compared with the fractional-order nonsingular terminal sliding mode controller, sliding mode controller based on a disturbance observer, and integral sliding mode controller methods.

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