Nonlinear disturbance observer based sliding mode control of a human-driven knee joint orthosis

Mohammed, Samer; Huo, Weiguang; Huang, Jian; Rifaï, Hala; Amirat, Yacine

doi:10.1016/j.robot.2014.10.013

Cited by 82 publications

(82 citation statements)

References 19 publications

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“…In literature, many studies have found that the traditional SMC is not able to achieve satisfactory tracking performance and can cause high chattering (29–31). Mohammed et al have designed SMCNDO for a pneumatic muscle system (28), Deshpande et al have designed SMCNDO for an active suspension systems (32), the results of these studies show that the tracking performance is obviously improved by SMCNDO as compared with the traditional SMC, which is consistent with the results of our study. By adding the nonlinear disturbance observer to estimate disturbances and feed them back in the control loop, tracking accuracy can be effectively improved.…”

Section: Discussionsupporting

confidence: 91%

“…A nonlinear disturbance observer has been introduced in many studies (26–28). In this study, a nonlinear disturbance observer is designed for the wire-driven robot to estimate and compensate disturbances and uncertainties that exist in the rehabilitation training, which can be defined as follows:

\overset{bold-italicd}{true} MathClass-rel= bold-italicq MathClass-bin+ bold-italic γ bold-italicM \overset{bold-italicp}{true}

\overset{q}{true} MathClass-rel= bold-italic γ (bold-italicG MathClass-bin- bold-italicu MathClass-bin- \overset{bold-italicd}{true})

where d is estimated as

\overset{bold-italicd}{true}

, q is an auxiliary vector, γ = diag(γ x γ y γ z ) is a symmetric diagonal positive matrix.…”

Section: Methodsmentioning

confidence: 99%

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Sliding Mode Tracking Control of a Wire-Driven Upper-Limb Rehabilitation Robot with Nonlinear Disturbance Observer

et al. 2017

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Robot-aided rehabilitation has become an important technology to restore and reinforce motor functions of patients with extremity impairment, whereas it can be extremely challenging to achieve satisfactory tracking performance due to uncertainties and disturbances during rehabilitation training. In this paper, a wire-driven rehabilitation robot that can work over a three-dimensional space is designed for upper-limb rehabilitation, and sliding mode control with nonlinear disturbance observer is designed for the robot to deal with the problem of unpredictable disturbances during robot-assisted training. Then, simulation and experiments of trajectory tracking are carried out to evaluate the performance of the system, the position errors, and the output forces of the designed control scheme are compared with those of the traditional sliding mode control (SMC) scheme. The results show that the designed control scheme can effectively reduce the tracking errors and chattering of the output forces as compared with the traditional SMC scheme, which indicates that the nonlinear disturbance observer can reduce the effect of unpredictable disturbances. The designed control scheme for the wire-driven rehabilitation robot has potential to assist patients with stroke in performing repetitive rehabilitation training.

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Section: Discussionsupporting

confidence: 91%

\overset{bold-italicd}{true} MathClass-rel= bold-italicq MathClass-bin+ bold-italic γ bold-italicM \overset{bold-italicp}{true}

\overset{q}{true} MathClass-rel= bold-italic γ (bold-italicG MathClass-bin- bold-italicu MathClass-bin- \overset{bold-italicd}{true})

where d is estimated as

\overset{bold-italicd}{true}

, q is an auxiliary vector, γ = diag(γ x γ y γ z ) is a symmetric diagonal positive matrix.…”

Section: Methodsmentioning

confidence: 99%

Sliding Mode Tracking Control of a Wire-Driven Upper-Limb Rehabilitation Robot with Nonlinear Disturbance Observer

et al. 2017

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“…In real time, to have further improvement in the tracking performance, the unknown disturbance needs to be estimated, and estimated disturbance need to be considered in the control algorithms. Nowadays, many research works are focused on this concern . In the work of Lu et al, a sliding mode disturbance observer (SMDO) is used to estimate unknown disturbance.…”

Section: Introductionmentioning

confidence: 99%

Disturbance observer–based adaptive boundary layer sliding mode controller for a type of nonlinear multiple‐input multiple‐output system

Gurumurthy

Das

2019

Intl J Robust & Nonlinear

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Summary In this paper, a disturbance observer–based adaptive boundary layer sliding mode controller (ABLSMC) is proposed to compensate external disturbance and system uncertainty for a class of output coupled multiple‐input multiple‐output (MIMO) nonlinear systems. To show the effectiveness of the proposed ABLMSC, a traditional adaptive sliding mode controller (ASMC) is also designed. The stability of the closed‐loop system is examined by using the Lyapunov stability approach. The proposed control approach is implemented for a class of nonlinear output coupled MIMO systems. For real‐time validation, a coupled tank system is considered for study. Finally, simulation and real‐time results show that the proposed ABLMSC gives better performance such as reduced chattering and energy efficiency than that of the ASMC and some reported works in the literature.

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“…In modeling, taking the human effects as disturbance [22], widely used in exoskeleton researches, is unreasonable. Human body is a part of the system obviously.…”

Section: Introductionmentioning

confidence: 99%

Command Filter Backstepping Sliding Model Control for Lower‐Limb Exoskeleton

Yang

Zhang

Wang

et al. 2017

Mathematical Problems in Engineering

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A command filter adaptive fuzzy backstepping control strategy is proposed for lower-limb assisting exoskeleton. Firstly, the humanrobot model is established by taking the human body as a passive part, and a coupling torque is introduced to describe the interaction between the exoskeleton and human leg. Then, Vicon motion capture system is employed to obtain the reference trajectory. For the purpose of obviating the "explosion of complexity" in conventional backstepping, a second-order command filter is introduced into the sliding mode control strategy. The fuzzy logic systems (FLSs) are also applied to handle with the chattering problem by estimating the uncertainties and disturbances. Furthermore, the stability of the closed-loop system is proved based on the Lyapunov theory. Finally, simulation results are presented to illustrate the effectiveness of the control strategy.

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Nonlinear disturbance observer based sliding mode control of a human-driven knee joint orthosis

Cited by 82 publications

References 19 publications

Sliding Mode Tracking Control of a Wire-Driven Upper-Limb Rehabilitation Robot with Nonlinear Disturbance Observer

Sliding Mode Tracking Control of a Wire-Driven Upper-Limb Rehabilitation Robot with Nonlinear Disturbance Observer

Disturbance observer–based adaptive boundary layer sliding mode controller for a type of nonlinear multiple‐input multiple‐output system

Command Filter Backstepping Sliding Model Control for Lower‐Limb Exoskeleton

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