• Title/Summary/Keyword: Upper limb Exoskeleton

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Passivity Based Adaptive Control and Its Optimization for Upper Limb Assist Exoskeleton Robot (상지 근력 보조용 착용형 외골격 로봇의 수동성 기반 적응 제어와 최적화 기법)

  • Khan, Abdul Manan;Ji, Young Hoon;Ali, Mian Ashfaq;Han, Jung Soo;Han, Chang Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.10
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    • pp.857-863
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    • 2015
  • The need for human body posture robots has led researchers to develop dexterous design of exoskeleton robots. Quantitative techniques to assess human motor function and generate commands for robots were required to be developed. In this paper, we present a passivity based adaptive control algorithm for upper limb assist exoskeleton. The proposed algorithm can adapt to different subject parameters and provide efficient response against the biomechanical variations caused by subject variations. Furthermore, we have employed the Particle Swarm Optimization technique to tune the controller gains. Efficacy of the proposed algorithm method is experimentally demonstrated using a seven degree of freedom upper limb assist exoskeleton robot. The proposed algorithm was found to estimate the desired motion and assist accordingly. This algorithm in conjunction with an upper limb assist exoskeleton robot may be very useful for elderly people to perform daily tasks.

The control of an upper extremity exoskeleton for stroke rehabilitation: An active force control scheme approach

  • Majeed, Anwar P.P. Abdul;Taha, Zahari;Abdullah, Muhammad Amirul;Azmi, Kamil Zakwan Mohd;Zakaria, Muhammad Aizzat
    • Advances in robotics research
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    • v.2 no.3
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    • pp.237-245
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    • 2018
  • This study evaluates the efficacy of a class robust control scheme namely active force control in performing a joint based trajectory tracking of an upper limb exoskeleton in rehabilitating the elbow joint. The plant of the exoskeleton system is obtained via system identification method whilst the PD gains were tuned heuristically. The estimated inertial parameter that enables the AFC disturbance rejection effect is attained by means of a non-nature based metaheuristic optimisation technique known as simulated Kalman filter (SKF). It was demonstrated from the present investigation that the proposed PDAFC scheme outperformed the classical PD algorithm in tracking the prescribed trajectory both in the presence and without the presence of disturbance attributed by the mannequin limb weights (1 kg and 1.5 kg) that mimics the weight of actual human limb weight. Therefore, it is apparent from the results obtained from the present study that the proposed control scheme, i.e., PDAFC is suitable for the application of exoskeleton for stroke rehabilitation.

Improved Wearability of the Upper Limb Rehabilitation Robot NREX with respect to Shoulder Motion (어깨의 움직임을 중심으로 한 상지재활로봇 NREX의 착용감 개선)

  • Song, Jun-Yong;Lee, Seong-Hoon;Song, Won-Kyung
    • The Journal of Korea Robotics Society
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    • v.14 no.4
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    • pp.318-325
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    • 2019
  • NREX, an upper limb exoskeleton robot, was developed at the National Rehabilitation Center to assist in the upper limb movements of subjects with weak muscular strength and control ability of the upper limbs, such as those with hemiplegia. For the free movement of the shoulder of the existing NREX, three passive joints were added, which improved its wearability. For the flexion/extension movement and internal/external rotation movement of the shoulder of the robot, the ball lock pin is used to fix or rotate the passive joint. The force and torque between a human and a robot were measured and analyzed in a reaching movement for four targets using a six-axis force/torque sensor for 20 able-bodied subjects. The addition of two passive joints to allow the user to rotate the shoulder can confirm that the average force of the upper limb must be 31.6% less and the torque must be 48.9% less to perform the movement related to the axis of rotation.

Twisted String-based Upper Limb Exoskeleton (줄꼬임에 기반한 상지 외골격 로봇)

  • Lee, Seung-Jun;Ryu, Jee-Hwan
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.11
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    • pp.960-966
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    • 2016
  • This paper proposes a new concept of a soft and wearable upper-limb exoskeleton. A novel actuation principle, called the twisted string actuation principle, is implemented to make it lightweight, soft, and therefore easily wearable. Its power transmission mechanism and harness are designed to be soft and wearable, yet have enough control accuracy for rehabilitation. In addition to force transmission optimization, a speed enlargement mechanism is newly introduced in order to increase the contraction speed of the twisted string actuation mechanism by sacrificing the unnecessarily large gear reduction ratio of the twisted string mechanism. A prototype has been tested for mirroring therapy, and the feasibility of the proposed mechanism has been shown through a sufficiently accurate tracking performance.