Abstract: This paper proposes a new upper-limb exoskeleton to reduce worker physical strain. The proposed design is based on a novel PRRRP (P-Prismatic; R-Revolute) kinematic chain with 5 passive Degrees of Freedom (DoF). Utilizing a magnetic spring, the proposed mechanism includes a specially designed locking mechanism that maintains any desired task posture. The proposed exoskeleton incorporates a balancing mechanism to alleviate discomfort and spinal torsional effects also helping in limb weight relief. This paper reports specific models and simulations to demonstrate the feasibility and effectiveness of the proposed design. An experimental characterization is performed to validate the performance of the mechanism in terms of forces and physical strain during a specific application consisting of ceiling-surface drilling tasks. The obtained results preliminarily validate the engineering feasibility and effectiveness of the proposed exoskeleton in the intended operation task thereby requiring the user to exert significantly less force than when not wearing it.

Key words: Assistive mechanism , · Exoskeleton , · Locking mechanism, Bionic robot