Latest Papers

ASME Journal of Mechanisms and Robotics

  • Investigation on a Class of 2D Profile Amplified Stroke Dielectric Elastomer Actuators
    on September 24, 2024 at 12:00 am

    AbstractDielectric elastomer actuators (DEAs) have been widely studied in soft robotics due to their muscle-like movements. Linear DEAs are typically tensioned using compression springs with positive stiffness or weights directly attached to the flexible film of the DEA. In this paper, a novel class of 2D profile linear DEAs (butterfly- and X-shaped linear DEAs) with compact structure is introduced, which, employing negative-stiffness mechanisms, can largely increase the stroke of the actuators. Then, a dynamic model of the proposed amplified-stroke linear DEAs (ASL-DEAs) is developed and used to predict the actuator stroke. The fabrication process of linear DEAs is presented. This, using compliant joints, 3D-printed links, and dielectric elastomer, allows for rapid and affordable production. The experimental validation of the butterfly- and X-shaped linear DEAs proved capable of increasing the stroke up to 32.7% and 24.0%, respectively, compared with the conventional design employing springs and constant weights. Finally, the dynamic model is validated against the experimental data of stroke amplitude and output force; errors smaller than 10.5% for a large stroke amplitude (60% of maximum stroke) and 10.5% on the output force are observed.

Origami Claw Tessellation and Its Stacked Structure

Abstract

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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