Sliding mode control of an exoskeleton robot for use in upper-limb rehabilitation

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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Adaptive integral terminal sliding mode control for upper-limb rehabilitation exoskeleton

Control Engineering Practice ◽

10.1016/j.conengprac.2018.02.013 ◽

2018 ◽

Vol 75 ◽

pp. 108-117 ◽

Cited By ~ 32

Author(s):

A. Riani ◽

T. Madani ◽

A. Benallegue ◽

K. Djouani

Keyword(s):

Sliding Mode Control ◽

Upper Limb ◽

Sliding Mode ◽

Terminal Sliding Mode Control ◽

Terminal Sliding Mode ◽

Upper Limb Rehabilitation ◽

Mode Control ◽

Limb Rehabilitation

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A Novel Exoskeleton with Fractional Sliding Mode Control for Upper Limb Rehabilitation

Robotica ◽

10.1017/s0263574719001851 ◽

2020 ◽

Vol 38 (11) ◽

pp. 2099-2120 ◽

Cited By ~ 1

Author(s):

Md Rasedul Islam ◽

Mehran Rahmani ◽

Mohammad Habibur Rahman

Keyword(s):

Sliding Mode Control ◽

Upper Limb ◽

Control Algorithm ◽

Sliding Mode ◽

Lyapunov Theory ◽

Upper Limb Rehabilitation ◽

Mode Control ◽

Wide Range ◽

The Stability ◽

Limb Rehabilitation

SUMMARYThe robotic intervention has great potential in the rehabilitation of post-stroke patients to regain their lost mobility. In this paper, firstly, we present a design of a novel, 7 degree-of-freedom (DOF) upper limb robotic exoskeleton (u-Rob) that features shoulder scapulohumeral rhythm with a wide range of motions (ROM) compared to other existing exoskeletons. An ergonomic shoulder mechanism with two passive DOF was included in the proposed exoskeleton to provide scapulohumeral motion with corresponding full ROM. Also, the joints of u-Rob have more range of motions compared to its existing counterparts. Secondly, we propose a fractional sliding mode control (FSMC) to control u-Rob. Applying the Lyapunov theory to the proposed control algorithm, we showed the stability of it. To control u-Rob, FSMC has shown effectiveness to handle unmodeled dynamics (e.g. friction, disturbance, etc.) in terms of better tracking and chatter compared to traditional SMC.

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