Latest Papers

ASME Journal of Mechanisms and Robotics

  • Mechanical Characterization of Supernumerary Robotic Tails for Human Balance Augmentation
    on August 31, 2023 at 12:00 am

    AbstractHumans are intrinsically unstable in quiet stance from a rigid body system viewpoint; however, they maintain balance, thanks to neuro-muscular sensory control properties. With increasing levels of balance related incidents in industrial and ageing populations globally each year, the development of assistive mechanisms to augment human balance is paramount. This work investigates the mechanical characteristics of kinematically dissimilar one and two degrees-of-freedom (DoF) supernumerary robotic tails for balance augmentation. Through dynamic simulations and manipulability assessments, the importance of variable coupling inertia in creating a sufficient reaction torque is highlighted. It is shown that two-DoF tails with solely revolute joints are best suited to address the balance augmentation issue. Within the two-DoF options, the characteristics of open versus closed loop tails are investigated, with the ultimate design selection requiring trade-offs between environmental workspace, biomechanical factors, and manufacturing ease to be made.

Origami Claw Tessellation and Its Stacked Structure


Origami tessellations belong to a type of origami in which repetitive units are used. Stacking sheets of these origami tessellations is a fabrication technique to construct mechanical cellular meta-materials. Almost all crease-stackable origami tessellations investigated to date are based on the Miura-ori and its derivatives, which contain only four-crease vertices. Such origami tessellations typically have a single degree-of-freedom (DOF), and the stacked origami tessellations retain that DOF. In this paper, we explore the possibility of creating stackable origami using origami tessellations that are not based on the Miura-ori. A novel origami tessellation called the origami claw tessellation (OCT) is proposed. This tessellation contains both four and six-crease vertices and has multiple DOFs. It is purposely designed so that the tessellation is crease-stackable. Moreover, we demonstrate that the crease-stacked OCTs have only a single DOF due to the mechanical coupling between the layers, a feature that has never been previously explored in stackable origami. Our findings have been proven analytically and validated using physical models. This work could inspire more research into using other exotic origami tessellations to create multi-layered cellular meta-materials.

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