Adaptive Tracking Control of an Exoskeleton Robot With Uncertain Dynamics Based on Estimated Time-Delay Control

Brahmi, Brahim; Saad, Maarouf; Ochoa-Luna, Cristóbal; Rahman, Mohammad Habibur; Brahmi, Abdelkrim

doi:10.1109/tmech.2018.2808235

Cited by 94 publications

(62 citation statements)

References 38 publications

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“…Using lagrange-Euler methodology, the robotic dynamics [31] of the of the upper limb robot can be described as following nonlinear differential equation as shown in (2).…”

Section: Dynamic Modelmentioning

confidence: 99%

Sliding Mode Control for 2 Degrees of Freedom Upper Limb Rehabilitation Robotic System under Uncertainties

Ahmed,

Raza,

Hussian

et al. 2019

IJEAT

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Rehabilitation of patients suffering from post-stroke injuries via robots is now adapted word widely. The aim of this therapy is to restore and improve the dysfunction and the performance of the affected limbs doing repetitive tasks with the help of rehabilitation robots, as robots are best way to perform repetitive task without any monotony failure. Control of these rehabilitation robots is an important part to consider because of nonlinearity and uncertainty of the system. This paper presents nonlinear sliding mode controller (SMC) for controlling a 2 degrees of freedom (DOF) upper limb robotic manipulator. Sliding mode control is able to handle system uncertainties and parametric changes. One drawback of using SMC is high frequency oscillations called as chattering. This chattering can be reduced by using boundary layer technique. Experiments have been carried out under perturbed conditions and results have shown that SMC performs well and remain stable and thus proves to robust controller for upper limb robotic manipulator.

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“…Using lagrange-Euler methodology, the robotic dynamics [31] of the of the upper limb robot can be described as following nonlinear differential equation as shown in (2).…”

Section: Dynamic Modelmentioning

confidence: 99%

Sliding Mode Control for 2 Degrees of Freedom Upper Limb Rehabilitation Robotic System under Uncertainties

Ahmed,

Raza,

Hussian

et al. 2019

IJEAT

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show abstract

“…Different from the existing TDC schemes [14][15][16][17][18][19][20][21][22][23][24][25][26][27], our proposed TDC scheme uses a combined reaching law to enhance the control performance under time-varying uncertainties. Taking (9) and (10) for further analysis, we can see that the combined reaching law has two elements, i.e., a well-known fast-TSM-type reaching law and a constant speed reaching law with adaptive gain.…”

Section: Tdc Scheme Design With Antsm Dynamicsmentioning

confidence: 99%

“…The core element of TDC scheme is 2 Mathematical Problems in Engineering the so-called time delay estimation (TDE), which uses the time-delayed values of the system states to estimate the remaining system dynamics and ensures a model-free feature. Thanks to the above attractive feature, TDC control has been widely used in lots of systems [21][22][23][24][25][26][27]. By combining TDE with other robust control schemes, exciting results have been obtained.…”

Section: Introductionmentioning

confidence: 99%

A New Model-Free Trajectory Tracking Control for Robot Manipulators

Wang

Zhu

Chen

et al. 2018

Mathematical Problems in Engineering

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In this paper, we propose a novel model-free trajectory tracking control for robot manipulators under complex disturbances. The proposed method utilizes time delay control (TDC) as its control framework to ensure a model-free scheme and uses adaptive nonsingular terminal sliding mode (ANTSM) to obtain high control accuracy and fast dynamic response under lumped disturbance. Thanks to the application of adaptive law, the proposed method can ensure high tracking accuracy and effective suppression of noise effect simultaneously. Stability of the closed-loop control system is proved using Lyapunov method. Finally, the effectiveness and advantages of the newly proposed TDC scheme with ANTSM dynamics are verified through several comparative simulations.

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“…In the study of LLRE control strategies for the rehabilitation training of patients with residual muscle strength in their affected limbs, two main issues need attention. The first is how exoskeleton adaptively adjusts training tasks according to the condition of different patients' affected lower limbs [15][16][17]. The second is how to optimize the exoskeleton control strategy based on the active muscle force of the patients' lower limbs, so that they can participate in rehabilitation training as much as possible to achieve maximum exercise of the muscles.…”

Section: Introductionmentioning

confidence: 99%

An Adaptive Sliding Mode Variable Admittance Control Method for Lower Limb Rehabilitation Exoskeleton Robot

Zhu

Song

et al. 2020

Applied Sciences

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As passive rehabilitation training with fixed trajectory ignores the active participation of patients, in order to increase the active participation of patients and improve the effect of rehabilitation training, this paper proposes an innovative adaptive sliding mode variable admittance (ASMVA) controller for the Lower Limb Rehabilitation Exoskeleton Robot. The ASMVA controller consists of an outer loop with variable admittance controller and an inner loop with an adaptive sliding mode controller. It estimates the wearer's active muscle strength and movement intention by judging the deviation between the actual and standard interaction force of the wearer's leg and the exoskeleton, thereby adaptively changing admittance controller parameters to alter training intensity. Three healthy volunteers engaged in further experimental studies, including trajectory tracking experiments with no admittance, fixed admittance, and variable admittance adjustment. The experimental results show that the proposed ASMVA control scheme has high control accuracy. Besides, the ASMVA can not only increase training intensity according to the active muscle strength of the patient during positive movement intention (so as to increase active participation of the patient), but also increase the amount of trajectory adjustment during negative movement intention to ensure the safety of the patient.

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Adaptive Tracking Control of an Exoskeleton Robot With Uncertain Dynamics Based on Estimated Time-Delay Control

Cited by 94 publications

References 38 publications

Sliding Mode Control for 2 Degrees of Freedom Upper Limb Rehabilitation Robotic System under Uncertainties

Sliding Mode Control for 2 Degrees of Freedom Upper Limb Rehabilitation Robotic System under Uncertainties

A New Model-Free Trajectory Tracking Control for Robot Manipulators

An Adaptive Sliding Mode Variable Admittance Control Method for Lower Limb Rehabilitation Exoskeleton Robot

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