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.

Kinematics and Performance Analysis of a Deployable 7R Overconstrained Single-Loop Mechanism for Aerospace Platform

Abstract

This paper studies a special deployable 7R single-loop mechanism (SLM), which is characterized by its overconstraints, 1-DOF, and single-loop structure. Based on these characteristics, a series of performance evaluation indices, including the overconstraint performance, input and output motion/force transmission performance, and deploying/folding ratio, are proposed to evaluate its performance. To analyze these performances, the kinematics of the 7R SLM is analyzed. Then, these performance indices are used to evaluate the 7R SLM. The performance analysis result shows that the mechanism exhibits excellent performance. A 3D-printed prototype of the 7R overconstrained SLM is presented and used to assemble a deployable module. Their deploying motion verifies the assembly capability and deployability of the mechanism and its potential as a basic unit to construct more complex, overconstrained deployable mechanisms for aerospace platforms. This study plays a significant role in the analysis, design, and optimization of overconstrained SLMs while also providing theoretical support for applications in aerospace platforms and other related fields.

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