scholarly journals Robust adaptive global nonlinear sliding mode controller for a quadrotor under external disturbances and uncertainties

2020 ◽  
Vol 12 (11) ◽  
pp. 168781402097523
Author(s):  
Moussa Labbadi ◽  
Yassine El Houm ◽  
Ahmed Abbou ◽  
Mohamed Cherkaoui
Keyword(s):  
Sliding Mode ◽  
Upper Bounds ◽  
Initial Time ◽  
Control Law ◽  
Sliding Mode Controller ◽  
External Disturbances ◽  
Control Approach ◽  
Adaptive Laws ◽  
Robust Adaptive ◽  
The Stability

The present paper proposes an adaptive global nonlinear sliding mode controller (AGNSMC) for the tracking problem of a quadrotor subjected to external disturbances. In order to eliminate the reaching phase and to guarantee the sliding mode of the quadrotor states in the initial time, a novel control law is developed. The upper bounds of disturbances affected the quadrotor dynamics are rejected based on adaptive laws for the both attitude and position subsystem. The tracking performance is enhanced by using the suggested controller. The stability of quadrotor is guaranteed and the global sliding mode surfaces converge to origin values in a finite time. To show the robustness of the proposed control approach against the external disturbances, simulation results are presented and compared with the results of the super-twisting-integral sliding mode controller.

Robust Adaptive Tracking Control of Uncertain Rehabilitation Exoskeleton Robot

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Brahim Brahmi ◽  
Abdelkrim Brahmi ◽  
Maarouf Saad ◽  
Guy Gauthier ◽  
Mohammad Habibur Rahman
Keyword(s):  
Sliding Mode ◽  
Robust Adaptive Control ◽  
Human Robot Interaction ◽  
Adaptive Sliding Mode Control ◽  
Control Law ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Control Approach ◽  
Exoskeleton Robot ◽  
Robust Adaptive

Abstract Rehabilitation robots have become an influential tool in physiotherapy treatment because they are able to provide intensive rehabilitation treatment over a long period of time. However, this technology still suffers from various problems such as dynamic uncertainties, external disturbances, and human–robot interaction. In this paper, we propose a robust adaptive control approach of an exoskeleton robot with an unknown dynamic model and external disturbances. First, the dynamics of the exoskeleton's arm is presented. Then, we design a robust adaptive sliding mode control in which the parameter uncertainties and the disturbances are estimated by the adaptive update methods. The proposed control ensures a good tracking of the system with a finite time convergence of sliding surface to zero. Throughout this paper, the designed control law and the global stability analysis are formulated and demonstrated based on the appropriate choice of the candidate Lyapunov function. The experimental and comparative results, performed for seven degrees-of-freedom (DOFs) exoskeleton arm with three healthy subjects to track a passive rehabilitation motion, confirm the effectiveness and robustness of the proposed control law compared with conventional adaptive approach.

scholarly journals Nonlinear PD plus sliding mode control with application to a parallel delta robot

2018 ◽  
Vol 69 (5) ◽  
pp. 329-336 ◽  
Author(s):  
Chems Eddine Boudjedir ◽  
Djamel Boukhetala ◽  
Mohamed Bouri
Keyword(s):  
Convergence Rate ◽  
Error Rate ◽  
Trajectory Tracking ◽  
Sliding Mode ◽  
Tracking Error ◽  
Sliding Mode Controller ◽  
External Disturbances ◽  
On Line ◽  
Delta Robot ◽  
The Stability

Abstract In this paper, a hybrid nonlinear proportional-derivative-sliding mode controller (NPD-SMC) is developed for the trajectory tracking of robot manipulators. The proposed controller combines the advantage of the easy implementation of NPD control and the robustness of SMC. The gains of PD control are tuned on-line in order to increase the convergence rate, whereas the SMC term is introduced to reject the external disturbances without requiring to know the system dynamics. The stability of the NPD-SMC is proved using Lyaponuv theorem, and it is demonstrated that the tracking error and the tracking error rate converge asymptotically to zero. Experiments are carried out on the parallel Delta robot to illustrate the effectiveness and robustness of the proposed approach. It is also shown the superiority of the NPD-SMC control over the NPD control and PD-SMC control.

scholarly journals Design of a robust tracking controller for a nonholonomic mobile robot based on sliding mode with adaptive gain

2021 ◽  
Vol 18 (1) ◽  
pp. 172988142098708
Author(s):  
Ameni Azzabi ◽  
Khaled Nouri
Keyword(s):  
Trajectory Tracking ◽  
Sliding Mode ◽  
External Disturbance ◽  
Salient Feature ◽  
Lyapunov Stability Theory ◽  
Stability And Convergence ◽  
Sliding Mode Controller ◽  
Tracking Errors ◽  
Adaptive Laws ◽  
The Stability

This article propounds addressing the design of a sliding mode controller with adaptive gains for trajectory tracking of unicycle mobile robots. The dynamics of this class of robots are strong, nonlinear, and subject to external disturbance. To compensate the effect of the unknown upper bounded external disturbances, a robust sliding mode controller based on an integral adaptive law is proposed. The salient feature of the developed controller resides in taking into account that the system is MIMO and the upper bound of disturbances is not priori known. Therefore, we relied on an estimation of each perturbation separately for each subsystem. Hence, the proposed controller provides a minimum acceptable errors and bounded adaptive laws with minimum of chattering problem. To complete the goal of the trajectory tracking, we apply a kinematic controller that takes into account the nonholonomic constraint of the robot. The stability and convergence properties of the proposed tracking dynamic and kinematic controllers are analytically proved using Lyapunov stability theory. Simulation results based on a comparative study show that the proposed controllers ensure better performances in terms of good robustness against disturbances, accuracy, minimum tracking errors, boundness of the adaptive gains, and minimum chattering effects.

scholarly journals Trajectory tracking of a mobile robot using adaptive sliding mode control

2021 ◽  
Author(s):  
Seyyed Mohammad Hosseini Rostami ◽  
Fatemeh Jahangiri
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Parametric Uncertainty ◽  
Adaptive Sliding Mode Control ◽  
Control Law ◽  
External Disturbances ◽  
Adaptive Sliding Mode ◽  
Mode Control ◽  
Angular Velocities ◽  
Robust Adaptive

Abstract The purpose of this paper is to design a control system for a mobile four-wheeled robot, whose task is to achieve stability and proper operation in the execution of commands. As a result of the nonlinear dynamics, structural and parametric uncertainty of this robot, various control approaches are used in order to achieve stability, proper performance, minimize modeling errors and uncertainties, etc. By adjusting linear and angular velocities in the presence of external disturbances and parametric uncertainty, this algorithm is able to follow a predetermined trajectory based on the information contained in the signals received by the sensor from the trajectory.. In previous articles, the upper bound of uncertainty was assumed to be known. This paper makes the assumption that the upper band of uncertainty and disturbances in robotic systems is unknown, since, in many cases, we cannot know the extent of these uncertainties in practice. In our recent paper, we generalized the sliding mode control law and proved its effectiveness, so that by including an adaptive part to the control law, we transformed it into a robust-adaptive sliding mode control, and we could estimate the upper band uncertainties online based on these adaptive laws. This typology can be expressed as a distinct theorem with stable results. Simulations with MATLAB software demonstrate that the controller ensures optimal performance under external disturbances and parametric uncertainty with less fluctuations.

scholarly journals Inverse Optimal Attitude Stabilization of Flexible Spacecraft with Actuator Saturation

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Chutiphon Pukdeboon
Keyword(s):  
Actuator Saturation ◽  
Sliding Mode ◽  
Estimation Error ◽  
Flexible Spacecraft ◽  
Control Law ◽  
Optimal Control Strategy ◽  
External Disturbances ◽  
Control Lyapunov Function ◽  
Error Dynamics ◽  
The Stability

This paper presents a new robust inverse optimal control strategy for flexible spacecraft attitude maneuvers in the presence of external disturbances and actuator constraint. A new constrained attitude controller for flexible spacecraft is designed based on the Sontag-type formula and a control Lyapunov function. This control law optimizes a meaningful cost functional and the stability of the resulting closed-loop system is ensured by the Lyapunov framework. A sliding mode disturbance observer is used to compensate unknown bounded external disturbances. The ultimate boundedness of estimation error dynamics is guaranteed via a rigorous Lyapunov analysis. Simulation results are provided to demonstrate the performance of the proposed control law.

A new fractional sliding mode controller based on nonlinear fractional-order proportional integral derivative controller structure to synchronize fractional-order chaotic systems with uncertainty and disturbances

2021 ◽  
pp. 107754632098245
Author(s):  
Seyede Zeynab Mirrezapour ◽  
Assef Zare ◽  
Majid Hallaji
Keyword(s):  
Fractional Order ◽  
Chaotic Systems ◽  
Sliding Mode ◽  
Control Law ◽  
Sliding Mode Controller ◽  
Proportional Integral Derivative ◽  
Lyapunov Theorem ◽  
Control Approach ◽  
Proportional Integral ◽  
Bounded Disturbance

This study presents a new fractional sliding mode controller based on nonlinear fractional-order proportional integral derivative controllers to synchronize fractional-order chaotic systems with uncertainties and affected by disturbance. According to the proposed control approach, a new fractional order control law is presented which ensures robust and stable synchronization of chaotic systems in the presence of uncertainties of the master and slave systems and bounded disturbance according to Lyapunov theorem. The proposed sliding mode controller is used to synchronize two non-smooth chaotic jerk systems affected by disturbance and uncertainty. Simulation results verify effectiveness and robustness of the proposed control law.

scholarly journals Adaptive High Order Sliding Mode Controller Design for Hypersonic Vehicle with Flexible Body Dynamics

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Bailing Tian ◽  
Wenru Fan ◽  
Qun Zong ◽  
Jie Wang ◽  
Fang Wang
Keyword(s):  
Controller Design ◽  
Sliding Mode ◽  
Adaptive Controller ◽  
Hypersonic Vehicle ◽  
High Order ◽  
Lyapunov Theory ◽  
Sliding Mode Controller ◽  
Flexible Body Dynamics ◽  
Robust Adaptive ◽  
The Stability

This paper describes the design of a nonlinear robust adaptive controller for a flexible hypersonic vehicle model which is nonlinear, multivariable, and unstable, and includes uncertain parameters. Firstly, a control-oriented model is derived for controller design. Then, the model analysis is conducted for this model via input-output (I/O) linearized technique. Secondly, the sliding mode manifold is designed based on the homogeneity theory. Then, the adaptive high order sliding mode controller is designed to achieve the tracking for hypersonic vehicle where the upper bounds of the uncertainties are not known in advance. Furthermore, the stability of the system is proved via the Lyapunov theory. Finally, the Monte-Carlo simulation results on the full-order nonlinear model with aerodynamic uncertainties are provided to demonstrate the effectiveness of the proposed control strategy.

scholarly journals Robust Full Tracking Control Design of Disturbed Quadrotor UAVs with Unknown Dynamics

Aerospace ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 115 ◽  
Author(s):  
Nabil Nafia ◽  
Abdeljalil El Kari ◽  
Hassan Ayad ◽  
Mostafa Mjahed
Keyword(s):  
Tracking Control ◽  
Adaptive Systems ◽  
Sliding Mode ◽  
Physical Parameters ◽  
Control Law ◽  
Control Approach ◽  
Adaptive Fuzzy ◽  
Unknown Disturbances ◽  
The Stability ◽  
Interval Type

In this study, we develop a rigorous tracking control approach for quadrotor unmanned aerial vehicles (UAVs) with unknown dynamics, unknown physical parameters, and subject to unknown and unpredictable disturbances. In order to better estimate the unknown functions, seven interval type-2-adaptive fuzzy systems (IT2-AFSs) and five adaptive systems are designed. Then, a new IT2 adaptive fuzzy reaching sliding mode system (IT2-AFRSMS) which generates an optimal smooth adaptive fuzzy reaching sliding mode control law (AFRSMCL) using IT2-AFSs is introduced. The AFRSMCL is designed a way that ensures that its gains are efficiently estimated. Thus, the global proposed control law can effectively achieve the predetermined performances of the tracking control while simultaneously avoiding the chattering phenomenon, despite the approximation errors and all disturbances acting on the quadrotor dynamics. The adaptation laws are designed by utilizing the stability analysis of Lyapunov. A simulation example is used to validate the robustness and effectiveness of the proposed method of control. The obtained results confirm the results of the mathematical analysis in guaranteeing the tracking convergence and stability of the closed loop dynamics despite the unknown dynamics, unknown disturbances, and unknown physical parameters of the controlled system.

Design of adaptive optimal robust control for two-flexible-link manipulators in the presence of matched uncertainties

2020 ◽  
pp. 107754632093202
Author(s):  
Hamid Reza Shafei ◽  
Mohsen Bahrami ◽  
Heidar Ali Talebi
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Flexible Link ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Control Approach ◽  
Mode Control ◽  
Nonsingular Terminal Sliding Mode ◽  
Control Scheme ◽  
The Stability

This study uses a comprehensive control approach to deal with the trajectory tracking problem of a two-flexible-link manipulator subjected to model uncertainties. Because the control inputs of two-flexible-link manipulators are less than their state variables, the proposed controller should be able to tackle the stated challenge. Practically speaking, there is only a single control signal for each joint, which can be used to suppress link deflections and control joint trajectories. To achieve this objective, a novel optimal robust control scheme, with an updated gain under the adaptive law, has been developed in this work for the first time. In this regard, a nonsingular terminal sliding mode control approach is used as the robust controller and a control Lyapunov function is used as the optimal control law, to benefit from the advantages of both methods. To systematically deal with system uncertainties, an adaptive law is used to update the gain of nonsingular terminal sliding mode control. The advantage of this approach over the existing methods is that it not only can robustly and stably control an uncertain nonlinear system against external disturbances but also can optimally solve a quadratic cost function (e.g. minimization of control effort). The Lyapunov stability theory has been applied to verify the stability of the proposed approach. Moreover, to show the superiority of this method, the computer simulation results of the proposed method have been compared with those of an adaptive sliding mode control scheme. This comparison shows that the presented approach is capable of optimizing the control inputs while achieving the stability of the examined two-flexible-link manipulator in the presence of model uncertainties and external disturbances.

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