Technical Brief

A Low-Profile Soft Robotic Sixth-Finger for Grasp Compensation in Hand-Impaired Patients1

[+] Author and Article Information
Hong Kai Yap

NUS Graduate School for Integrative
Sciences and Engineering,
National University of Singapore,
Singapore 117456, Singapore;
Department of Biomedical Engineering,
National University of Singapore,
Singapore 117583, Singapore

James Cho Hong Goh

Department of Biomedical Engineering,
National University of Singapore,
Singapore 117583, Singapore

Chen-Hua Yeow

Department of Biomedical Engineering,
National University of Singapore,
Singapore 117583, Singapore;
Singapore Institute for Neurotechnology (SINAPSE),
National University of Singapore,
Singapore 117456, Singapore;
Advanced Robotics Center (ARC),
National University of Singapore,
Singapore 117580, Singapore

DOI: 10.1115/1.4033741Manuscript received March 1, 2016; final manuscript received March 17, 2016; published online August 1, 2016. Editor: William Durfee.

J. Med. Devices 10(3), 030914 (Aug 01, 2016) (2 pages) Paper No: MED-16-1085; doi: 10.1115/1.4033741 History: Received March 01, 2016; Revised March 17, 2016

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Copyright © 2016 by ASME
Topics: Actuators , Robotics
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Muellbacher, W. , Richards, C. , Ziemann, U. , Wittenberg, G. , Weltz, D. , Boroojerdi, B. , Cohen, L. , and Hallett, M. , 2002, “ Improving Hand Function in Chronic Stroke,” Arch. Neurol., 59(8), pp. 1278–1282. [CrossRef] [PubMed]
Rosenstein, L. , Ridgel, A. L. , Thota, A. , Samame, B. , and Alberts, J. L. , 2008, “ Effects of Combined Robotic Therapy and Repetitive-Task Practice on Upper-Extremity Function in a Patient With Chronic Stroke,” Am. J. Occup. Ther., 62(1), pp. 28–35. [CrossRef] [PubMed]
Maciejasz, P. , Eschweiler, J. , Gerlach-Hahn, K. , Jansen-Troy, A. , and Leonhardt, S. , 2014, “ A Survey on Robotic Devices for Upper Limb Rehabilitation,” J. NeuroEng. Rehabil., 11, p. 3. [CrossRef] [PubMed]
Polygerinos, P. , Wang, Z. , Galloway, K. C. , Wood, R. J. , and Walsh, C. J. , 2015, “ Soft Robotic Glove for Combined Assistance and At-Home Rehabilitation,” Rob. Auton. Syst., 73, pp. 135–143. [CrossRef]
Hong Kai, Y. , Jeong Hoon, L. , Nasrallah, F. , Goh, J. C. H. , and Yeow, R. C. H. , 2015, “ A Soft Exoskeleton for Hand Assistive and Rehabilitation Application Using Pneumatic Actuators With Variable Stiffness,” IEEE International Conference on Robotics and Automation (ICRA), Seattle, WA, May 26–30, pp. 4967–4972.
Hussain, I. , Salvietti, G. , Meli, L. , Pacchierotti, C. , Cioncoloni, D. , Rossi, S. , and Prattichizzo, D. , 2015, “ Using the Robotic Sixth Finger and Vibrotactile Feedback for Grasp Compensation in Chronic Stroke Patients,” IEEE International Conference on Rehabilitation Robotics (ICORR), Singapore, Aug. 11–14, pp. 67–72.


Grahic Jump Location
Fig. 1

(a) Computer-aided design drawing of the device, (b) rest, and (c) working position of the device

Grahic Jump Location
Fig. 2

(a) A soft actuator with corrugated-fabric layer to prevent undesired radial budging. (b) Fabrication process of the actuator: (i) pour liquid elastomer (DragonSkin 10, Smooth-On, Inc., Macungie, PA) to the channel mold, (ii) place the outer layer mold on top to create corrugated outer layer, (iii) the ensemble is cured under 60 °C, and (iv) a fabric was attached to the corrugated outer layer and seal the bottom of the cured structure with an inextensible fabric.

Grahic Jump Location
Fig. 3

(a) Force measurement setup and (b) force–pressure relationship of the actuator

Grahic Jump Location
Fig. 4

(a) Bimanual task: Unscrew the cap of a bottle with the assistance of the device. (b)–(d) Soft actuator adapted to objects with different sizes and shapes.



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