Robust adaptive fractional-order nonsingular terminal sliding mode stabilization of three-axis gimbal platforms

For the multi-degrees of freedom control problem of underwater hydraulic manipulators with non-ignorable valve deadband and strong lumped nonlinearities and uncertainties, a practical continuous fractional-order nonsingular terminal sliding mode control design together with a deadband compensator is presented and studied. The presented method contains three parts a time delay estimation utilized to nearly estimate and compensate the extremely complicated system dynamics, a continuous fractional-order nonsingular terminal sliding mode used to ensure high control performance against the strong lumped nonlinearities and uncertainties, and a valve deadband compensator used to compensate for the non-ignorable valve deadband. The proposed method is model-free thanks to the time delay estimation, and can ensure satisfactory control performance thanks to the continuous fractional-order nonsingular terminal sliding mode and deadband compensator. Stability of the closed-loop control system including the deadband compensator is proved rigorously. Finally, practical 2-degrees of freedom experiments are performed, and corresponding results effectively demonstrate the superiorities of the newly presented controller with deadband compensator.

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

Journal of Vibration and Control ◽

10.1177/1077546320925263 ◽

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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Practical adaptive fractional‐order nonsingular terminal sliding mode control for a cable‐driven manipulator

International Journal of Robust and Nonlinear Control ◽

10.1002/rnc.4441 ◽

2018 ◽

Vol 29 (5) ◽

pp. 1396-1417 ◽

Cited By ~ 39

Author(s):

Yaoyao Wang ◽

Binbin Li ◽

Fei Yan ◽

Bai Chen

Keyword(s):

Sliding Mode Control ◽

Fractional Order ◽

Sliding Mode ◽

Terminal Sliding Mode Control ◽

Terminal Sliding Mode ◽

Mode Control ◽

Nonsingular Terminal Sliding Mode

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Output Feedback Fractional-Order Nonsingular Terminal Sliding Mode Control of Underwater Remotely Operated Vehicles

The Scientific World JOURNAL ◽

10.1155/2014/838019 ◽

2014 ◽

Vol 2014 ◽

pp. 1-19 ◽

Cited By ~ 3

Author(s):

Yaoyao Wang ◽

Jiawang Chen ◽

Linyi Gu

Keyword(s):

Sliding Mode Control ◽

Fractional Order ◽

Output Feedback ◽

Finite Time ◽

Sliding Mode ◽

Terminal Sliding Mode Control ◽

Remotely Operated Vehicles ◽

Terminal Sliding Mode ◽

Mode Control ◽

Nonsingular Terminal Sliding Mode

For the 4-DOF (degrees of freedom) trajectory tracking control problem of underwater remotely operated vehicles (ROVs) in the presence of model uncertainties and external disturbances, a novel output feedback fractional-order nonsingular terminal sliding mode control (FO-NTSMC) technique is introduced in light of the equivalent output injection sliding mode observer (SMO) and TSMC principle and fractional calculus technology. The equivalent output injection SMO is applied to reconstruct the full states in finite time. Meanwhile, the FO-NTSMC algorithm, based on a new proposed fractional-order switching manifold, is designed to stabilize the tracking error to equilibrium points in finite time. The corresponding stability analysis of the closed-loop system is presented using the fractional-order version of the Lyapunov stability theory. Comparative numerical simulation results are presented and analyzed to demonstrate the effectiveness of the proposed method. Finally, it is noteworthy that the proposed output feedback FO-NTSMC technique can be used to control a broad range of nonlinear second-order dynamical systems in finite time.

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Maximum Power Extraction from Wind Turbines Using a Fault-Tolerant Fractional-Order Nonsingular Terminal Sliding Mode Controller

Energies ◽

10.3390/en14185887 ◽

2021 ◽

Vol 14 (18) ◽

pp. 5887

Author(s):

Yashar Mousavi ◽

Geraint Bevan ◽

Ibrahim Beklan Küçükdemiral ◽

Afef Fekih

Keyword(s):

Fractional Order ◽

Wind Turbines ◽

Fault Tolerant ◽

Sliding Mode ◽

Power Production ◽

Maximum Power ◽

Production Performance ◽

Terminal Sliding Mode ◽

Power Extraction ◽

Nonsingular Terminal Sliding Mode

This work presents a nonlinear control approach to maximise the power extraction of wind energy conversion systems (WECSs) operating below their rated wind speeds. Due to nonlinearities associated with the dynamics of WECSs, the stochastic nature of wind, and the inevitable presence of faults in practice, developing reliable fault-tolerant control strategies to guarantee maximum power production of WECSs has always been considered important. A fault-tolerant fractional-order nonsingular terminal sliding mode control (FNTSMC) strategy to maximize the captured power of wind turbines (WT) subjected to actuator faults is developed. A nonsingular terminal sliding surface is proposed to ensure fast finite-time convergence, whereas the incorporation of fractional calculus in the controller enhances the convergence speed of system states and simultaneously suppresses chattering, resulting in extracted power maximisation by precisely tracking the optimum rotor speed. Closed-loop stability is analysed and validated through the Lyapunov stability criterion. Comparative numerical simulation analysis is carried out on a two-mass WT, and superior power production performance of the proposed method over other methods is demonstrated, both in fault-free and faulty situations.

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