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.

Rigid-Foldable Mechanism Inspired by Origami Twisted Tower

Abstract

Rigid origami mechanisms have great practical utility in different fields. This paper presents a rigid and foldable mechanism based on the origami artwork Twisted Tower. The mathematical model of the funnel-shaped tower cell was developed for the first time, which accurately describes its kinematic behavior. Based on this model, criteria for the appropriate geometry of the tower components are proposed to prevent internal interference in the tower mechanism during the twisting movement. In this paper, two geometric design cases of twisted tower mechanisms, including a normal-shaped tower and a heteromorphic tower, are presented. Several additional modifications were also imposed to adapt the proposed mechanism to generalized and standardized manufacturing and assembly. Experimental results illustrate that the kinematic characteristics of the fabricated mechanism meet its designed performance. Furthermore, the proposed mechanism is suitable for applications such as continuum manipulators, which exhibit much better resistance to external loads than their flexible-rigid hybrid counterparts.

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