Design and integration of a low-back exoskeleton: a 3d-printed cycloidal drive actuator for flexible human-robot interaction.

In the last decades, the adoption of assistive devices has been spreading among different application fields, starting from the rehabilitative medicine to the industrial field. In particular, exoskeletons aimed to ease the operations performed by workers have been developed in order to reduce the entity of work-related musculoskeletal disorders, limiting the inconvenience caused to the workers and reducing therapy-related costs faced by the employer or the healthcare system. However, commercial full-body exoskeletons equipped with efficient, low-weight actuation systems require a huge investment (both for purchase and maintenance), which only a few companies are willing to pay. In order to achieve high performance while limiting costs and complexity, a custom cycloidal reduction was designed: because of its back-drivability and scalability, it represents a low-cost solution capable of maximizing the overall performances of the assistive device. In this paper, the methodology to define a custom low-cost yet efficient cycloidal drive actuation is hence proposed, as well as its implementation in the design of a low-back exoskeleton based on backbone kinematics.