Characterization of an Antagonistic Actuation System with Nonlinear Compliance for an Upper-Arm Exoskeleton

The parallel connection of technical and biological systems with a comparable mechanical behavior offers the possibility reducing interaction forces between those systems. Especially in context human–robot (e.g., exoskeletons), it can improve user safety acceptance at same time. With this aim, we used antagonistic actuators nonlinear compliance for modular upper-extremity exoskeleton following paragons, mirroring “blueprint” its human user. In test-bed setup, compared compliant actuation stiff, unilateral stiff artificial “elbow joint” test bed. We show that type allows variation joint stiffness during motion, independent position. approach propose, leads to reduced force peaks angular jerk, without sacrifices terms time constants overshoot amplitudes. conclude presented principle has considerable benefits comparison other types actuation, even when using only commercially available 3D printed components. Based on our work, further investigations into control antagonistically actuated exoskeletons become realizable.