Design, Modeling And Experimental Validatio Of A Continuum Robot As A Shoulder Exoskeleton

Exoskeleton could enhance one’s physical capability or provide rehabilitation therapy to patients with neuromuscular defects after injury or stroke. However, most of the existing exoskeletons follow a similar design approach despite of the two distinct applications:articulated rigid links are actuated to mobilize a human wearer. Hence the resultant exoskeleton designs are usually bulky, costly and most importantly uncomfortable to wear because of the difficulty of assuring kinematic compatibility between the patient and the rigid mechanism.This master research proposes a novel flexible continuum exoskeleton design, aiming at improving comfort and ergonomics. Most importantly, this flexible continuum exoskeleton is capable of passively deforming itself to accommodate different anatomies of different patients while assisting therapeutic motions. Design, modeling, experimental characterization and vali-dation of such a continuum shoulder exoskeleton are presented to demonstrate the effectiveness of this new design approach.Kinematics and statics of a two-degree-of-freedom continuum mechanism which serves as the fundamental component are expanded from previously published results to the scenario where the to-be-assisted arm adds additional constraints to the continuum structure.Design overview and component descriptions of the exoskeleton are elaborated. Since all the secondary backbones are actuated in a push-pull mode according to a prescribed actuation pattern determined by the actuation kinematics, primary attentions are given to the designs of the actuation units. Two actuation schemes are studied in the thesis, one is to use a hydraulic transmission system, the other is to use a layered continuum transmission mechanism to achieve the push and pull motions. Mechatronic components are also described and control of the exoskeleton is implemented using Matlab xPC. Path planning in the exoskeleton’s configuration space is conducted to drive the exoskeleton from one configuration to another.Experimental validation of the exoskeleton is also carried out. Mockup upper arms with different anatomic parameters are successfully assisted by the exoskeleton. It is quantitatively shown that the flexible continuum exoskeleton passively deforms to different anatomies while assisting therapeutic motions. Errors in the assisted motions are also quantified and could be compensated accordingly.