Grasp force optimization in the design of an underactuated robotic hand

Jasper Schuurmans*, Richard Q. van der Linde, Dick H. Plettenburg, Frans C.T. van der Helm

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

11 Citations (Scopus)


For people without the ability to use their hands, gripper-equipped robotic aids may provide partial rehabilitation. This article discusses the optimization of an underactuated mechanism for a new prototype gripper on robotic aid ARM. When the underactuated mechanism of the tentacle-like Soft Gripper is translated to a three-phalange equivalent for the prototype, increasing forces on the proximal phalanges tend to drive objects out of the grasp when the finger flexes. To obtain equal grasp forces on all phalanges, the pulley radii in the mechanism were optimized. This could however only decrease the ratio between highest and lowest force from 4.0 to 2.9. An extra bi-articular tendon was added to the mechanism, which further improved this ratio to 1.5. The prototype gripper that was fitted with the bi-articular mechanism stably grasps and holds objects. Preliminary test with disturbance forces and torques on the grasped objects show a performance increase with respect to a parallel gripper mounted on ARM. However, some improvements on the bi-articular mechanism are necessary to make the force in the bi-articular tendon linearly dependent from the actuation force of the gripper.
Original languageEnglish
Title of host publicationProceedings IEEE 10th International Conference on Rehabilitation Robotics (IEEE ICORR 2007)
EditorsJ.L Herder, G.J. Gelderblom, B. Driessen
Place of PublicationPiscataway, NJ
ISBN (Electronic)978-1-4244-1320-1
ISBN (Print)978-1-4244-1319-5
Publication statusPublished - 12 Jun 2007
Externally publishedYes
EventIEEE 10th International Conference on Rehabilitations Robotics, ICORR 2007: Robots care! - Noordwijk, Netherlands
Duration: 13 Jun 200715 Jun 2007
Conference number: 10


ConferenceIEEE 10th International Conference on Rehabilitations Robotics, ICORR 2007
Abbreviated titleICORR


  • n/a OA procedure


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