Design and Evaluation of a Novel 5 DoF Underactuated Thumb-Exoskeleton

• Post by: System
• 27 November 2019
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© 2016 IEEE. This letter presents the design of a new exoskeleton for thumb. The main feature of this device is a high degree of underactuation. In fact, the five degrees of freedom (dof) of the thumb are actuated by just one linear actuator. Other features of the thumb-exos are its capability of exert only forces normal to the phalanx axis in the contact point, and its adaptability to different finger sizes. In this letter, the spatial kinematic model is described and the link lengths are determined by means of a genetic algorithm (GA) over four basic grasping poses and the open hand pose. Finally, the thumb-exos mechanism was implemented and integrated in a full hand exoskeleton device. Performance of the thumb exoskeleton in terms of adaptation to different objects and hand sizes, and in terms of grasping forces have been evaluated through experiments and measuring muscular activity, grasping pressure and forces at different locations of the mechanism.