Towards an Effective Robotic Device for Gait Rehabilitation of Children With Cerebral Palsy

Derbel

2023

IJEECS

<p>In this article, a lower limb exoskeleton (LLE) under contacting constrained motion has been modelled using augmented Lagrange equations which include Lagrange multiplier and Jacobian vectors. A sliding mode Controller optimized by the grey Wolf optimization algorithm has been used for controlling (LLE) in the case of constrained motion with uncertainties and outside perturbation. The grey wolf optimization algorithm has been used as an optimization algorithm for finding the optimal controllers’ parameters in order to improve the performance of the system. The stability analysis of the closed-loop system has been performed using Lyapunov theory of stability. To validate the effectiveness of the proposed controller structure grey wolf optimization algorithm controller (GW-SMC), a series of comparative simulations have been carried out with other types of recently existing sliding mode control (SMC). The results of numerical simulations indicate the superiority of the sliding mode optimized by the GW-SMC over other types of recently existing controller in terms of tracking errors and robustness towards uncertainties and external disturbances.</p>

Section: Controllers Developmentsmentioning

confidence: 99%

Optimal sliding mode controller for lower limb rehabilitation exoskeleton in constrained environments

Faraj

Derbel

2023

IJEECS

“…In this section, first, a sliding mode controller is proposed [10]. Define the sliding function as follows:…”

Section: Fuzzy Sliding Mode Controlmentioning

confidence: 99%

“…Recently, studies focus on the most important part which is the control of the exoskeletons using the adequate controllers [9]. Hence, in the present paper, we propose to control a two degrees of freedom lower limb exoskeleton at the hip and knee joints with a good tracking [6], [7], [10], [11]. The choice of the suitable and the robust controller law is fundamental [12], [13], [14].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Fuzzy Sliding Mode Controller for Reducing Torques Applied to a Rehabilitation Robot

2020 17th International Multi-Conference on Systems, Signals &Amp; Devices (SSD)

Medhaffar

Chemori

et al. 2020

Self Cite

Exoskeletons are the most efficient devices used to help children, suffering from several diseases, to walk compared to the use of wheelchairs. In rehabilitation, relearning to walk is very important. In fact, repetitive tasks improve human locomotory performances. This paper aims to deal with the control problem of a two degrees of freedom lower limb exoskeleton. During the control process, high torques are considered as a major constraint. Thus, a fuzzy sliding mode controller is implemented. Moreover, stability analysis are presented using Lyapunov theory.

“…Te main disadvantage of using this manual therapy is making therapists stressed while helping patients to recover their normal motion [2,3]. Tanks to their usefulness and efectiveness, lower limb rehabilitation exoskeletons (LLE) have been undertaken as robot-assisted physical therapy in the last decades as an efcient and excellent electromechanical rehabilitation device for augmentation and for strengthening the function of motion of lower limbs extremities [4,5].…”

Section: Introductionmentioning

confidence: 99%

Adaptive Fractional‐Order Super‐Twisting Sliding Mode Controller for Lower Limb Rehabilitation Exoskeleton in Constraint Circumstances Based on the Grey Wolf Optimization Algorithm

Faraj

Mathematical Problems in Engineering

Derbel

et al. 2023

Self Cite

In this work, a lower limb exoskeleton with uncertainties and external disturbances under constrained motion has been controlled by developing a model-free adaptive optimal fractional-ordersuper-twisting sliding mode (AOFSTSM) controller. Contrary to popular existing modeling methods, the modeling of the lower limb exoskeleton has been accomplished in the case of contact with the ground. A fractional-order operator and super-twisting sliding mode control have been combined to achieve an excellent tracking performance, chatter-free control inputs, and robustness to external disturbances and uncertainties. The controller structure is model-independent which has been derived without needing to know the dynamics of the system. An adaptive control strategy has been adopted as an approximating method to evaluate the uncertain dynamics of the system without the necessity for knowing the prior knowledge of the upper bounds. A grey wolf optimization technique has been used to find the optimal values of controller parameters. The stability of the overall system has been investigated and derived from the Lyapunov stability criterion. To validate the effectiveness of our proposed controller structure, a series of comparative simulations have been conducted with optimal fractional-order super-twisting sliding mode (OFSTSM) controller and fractional-order super-twisting sliding mode (FSTSM) controller. The comparative simulations have been also carried out with other types of recently existing control methods and recently existing optimization algorithms. The results of numerical simulations indicate the superiority of the AOFSTSM controller over other types of recently existing optimization algorithms and controllers in terms of tracking error and robustness towards the uncertainties and external disturbances.