Towards a multi-DOF passive balancing mechanism for upper limbs

Zhuoqi Cheng, Shaohui Foong, Defeng Sun, U. Xuan Tan*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

Abstract

Gravity balancing has great significance in many rehabilitation applications and one example is in minimizing the resistance of lifting a patient's upper limb due to its own weight. As compared to commonly used active method in exoskeleton, passive weight compensation offers many other advantages such as elimination of motors which reduces the overall load acting on the patient. However, the torque about each joint due to the weight of the upper and fore arm is dependent on the orientation and location of each other, which makes it a challenge to compensate. Hence, this paper proposes and develop a passive method to compensate the torques on each joint. The proposed design includes a decoupling mechanism for isolating the torsional effect between various linkages and a realizable torsional compliant beam which can provide a specific torsional stiffness function to compensate the torque due to the arm's weight. In place of the usual expensive zero-length spring as the solution, an algorithm that generates the appropriate compliant beam design is also presented in this paper. The end result of the manipulator arm is a reduced required joint torque for gravity compensation using only passive means. A two-DOF prototype, with easy possible extension of additional DOF, has been built, and experiments are performed to illustrate, verify and quantify the effectiveness of the proposed method.

Original languageEnglish
Title of host publicationProceedings of the IEEE/RAS-EMBS International Conference on Rehabilitation Robotics : Enabling Technology Festival, ICORR 2015
EditorsDavid Braun, Haoyong Yu, Domenico Campolo
PublisherIEEE
Publication date28. Sept 2015
Pages508-513
Article number7281250
ISBN (Electronic)9781479918072
DOIs
Publication statusPublished - 28. Sept 2015
Externally publishedYes
Event14th IEEE/RAS-EMBS International Conference on Rehabilitation Robotics, ICORR 2015 - Singapore, Singapore
Duration: 11. Aug 201514. Aug 2015

Conference

Conference14th IEEE/RAS-EMBS International Conference on Rehabilitation Robotics, ICORR 2015
Country/TerritorySingapore
CitySingapore
Period11/08/201514/08/2015
SeriesProceedings - IEEE International Conference on Rehabilitation Robotics
Volume2015-September
ISSN1945-7898

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