A Novel Design Concept of Digital Hydraulic Drive for Knee Exoskeleton
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Proceedings of the ASME/BATH 2021 Symposium on Fluid Power and Motion Control. Virtual, Online. October 19?21, 2021.
Hydraulic actuation of exoskeletons has gained interest among researchers due the potentials of high power density and energy recuperation allowing the reduction of mass and space used by the device (when compared to the traditional electrically actuated exoskeletons). However, developing a light and cost-effective design of such exoskeleton remains a key challenge.
In this work, a novel design of digitally driven knee exoskeleton is presented. The design uses simple hydraulic cylinders instead of multi-chamber cylinders (which are typically used in digital actuations and are expensive). The design also includes a unique mechanism that is able to satisfy the peak torque requirements during a typical gait cycle with a smaller hydraulic force. This ensures small size of hydraulic components and a moderate power demand from the energy source.
To study this exoskeleton design, a numerical model of the exoskeleton and the lower limb is developed in this work. The simulation results show that the design is able to track the motion of the knee in a typical gait cycle as well as satisfy the necessary torque requirements.