Preliminary Design of the Actuation System of a Wearable Upper Limb Exoskeleton

Wearable exoskeletons are a promising technological solution to prevent work-related musculoskeletal disorders caused by repetitive manual material handling and heavy loads lifting. Active exoskeletons that provide a well perceptible sense of effectiveness could overcome workers’ reluctance to wear a device that is often considered more as an impairment rather than real help. This paper deals with the preliminary design of the actuation framework of an upper limb exoskeleton designed to support the shoulder flexion/extension motion during repetitive lifting tasks in logistic applications. A low friction hybrid electrical/ hydraulic transmission is proposed. To obtain a reasonable range of flexion/ extension motion, a custom four-bar mechanism actuated by a hydrostatic transmission has been integrated in the exoskeleton kinematic chain. The synthesis of the actuated mechanism is presented.