Mechanical and Control Design of an Industrial Exoskeleton for Advanced Human Empowering in Heavy Parts Manipulation Tasks

Exoskeleton robots are a rising technology in industrial contexts to assist humans in
onerous applications. Mechanical and control design solutions are intensively investigated to
achieve a high performance human-robot collaboration (e.g., transparency, ergonomics, safety,
etc.). However, the most of the investigated solutions involve high-cost hardware, complex design
solutions and standard actuation. Moreover, state-of-the-art empowering controllers do not allow
for online assistance regulation and do not embed advanced safety rules. In the presented work,
an industrial exoskeleton with high payload ratio for lifting and transportation of heavy parts is
proposed. A low-cost mechanical design solution is described, exploiting compliant actuation at the
shoulder joint to increase safety in human-robot cooperation. A hierarchic model-based controller
with embedded safety rules is then proposed (including the modeling of the compliant actuator)
to actively assist the human while executing the task. An inner optimal controller is proposed for
trajectory tracking, while an outer safety-based fuzzy logic controller is proposed to online deform
the task trajectory on the basis of the human’s intention of motion. A gain scheduler is also designed
to calculate the inner optimal control gains on the basis of the performed trajectory. Simulations have
been performed in order to validate the performance of the proposed device, showing promising
results. The prototype is under realization.