Invited Research Lecture: Cable-driven Exoskeletons for Functional Training of Arm Movements

Date: 20 Jul 2012 - 20 Jul 2012

Venue: SIMTech Auditorium, Tower block, Level 3


This event is co-sponsored by IEEE RAS Chapter (Singapore).


Rehabilitation robots are currently being explored for training of neural impaired subjects or for assistance of those with weak limbs. A current limitation of exoskeletons for rehabilitation is that they require accurate alignment between exoskeletal and human joints. Precise alignment of exoskeletal joint axes with arm joint axes is nearly impossible due to the geometry of bony segments that form the joints and variability among subjects. Conventional arm exoskeletons for rehabilitation are also bulky and heavy. In recent years, the authors have proposed to make lightweight exoskeletons for rehabilitation by replacing the rigid links of the exoskeleton with lightweight cuffs fixed to the moving limb segments of the human arm [1]. Cables are routed through these cuffs, which are driven by motors, to move the limb segments relative to each other. The merits of the cable-based exoskeleton design are: (1) A cable design is nearly an order of magnitude lighter than current arm exoskeletons. (2) It does not have traditional links and joints, hence, does not require adjustment of link lengths and alignment of joint axes within the exoskeleton. (3) It does not restrict the natural DOFs of the human arm. (4) The architecture of the design is novel as the cables are routed from proximal to distal segments of the arm. However, a scientific limitation of a cable-driven system is that each cable can only pull but not push [3]. We demonstrate via experiments with a cable driven arm exoskeleton (CAREX) that it is possible to achieve desired forces on the hand, i.e., both pull and push, in any direction as required in neural training. The exoskeleton CAREX is currently being tested on humans, both healthy and survivors of stroke, from the perspective of movement training [2].


[1] Mao, Y. and Agrawal, S. K., "A Cable Driven Arm Exoskeleton (CAREX) for Neural Rehabilitation", available on-line as early access IEEE Transactions on Robotics, 2012.

[2] Mao, Y. and Agrawal, S. K., "Cable Driven ARm EXoskeleton (CAREX): Transition from experiments on a Mechanical Arm to the Human Arm", to appear in IEEE Intl. Conference on Robotics and Automation, 2012.

[3] Mustafa, S. K. and Agrawal S. K., "On the Force-Closure Analysis of n-DOF Cable-Driven Open Chains Based on Reciprocal Screw Theory",  IEEE Transactions on Robotics, Vol. 28, No. 1, 2012, 22-31



2.45 pm Registration

3.00 pm Invited Research Lecture by Professor Sunil Kumar Agrawal
4.00pm  Q&A and Networking session

4.30 pm End 

About the Speaker
Professor Sunil K. Agrawal received his Ph.D. degree in Mechanical Engineering from Stanford University in 1990. He is currently the Director of Mechanical Systems Laboratory and Rehabilitation Robotics Laboratory at the University of Delaware. He has published close to 300 journal and conference papers. Dr. Agrawal is a Fellow of the ASME and his honors include a NSF Presidential Faculty Fellowship from the White House in 1994, a Bessel Prize from Germany in 2003, a Humboldt US Senior Scientist Award in 2007, Best Paper award at the 35th ASME Robotics and Mechanisms Conference in 2011, and Best Student Paper Award at the IEEE International Conference on Robotics and Automation in 2012. He currently also holds the position of a distinguished visiting professor at Hanyang University in Korea. He has served on editorial boards of several journals published by ASME and IEEE.  



This is a non-chargeable event. To reserve a seat, please register online. 

Contact Us

Technical enquiries : Dr Mustafa S. Kurbanhusen,
Tel : 6793 1040,  Email :

General enquiries : Ms Alice Koh, Tel : 6793 8249,  Email :