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.

Optimization of Translational Flexure Joints Using Corrugated Units Under Stress Constraints

Abstract

When optimizing corrugated flexure (CF) joints, most approaches for calculating the maximum stress on the CF beam depend on finite element analysis (FEA). The current paper introduces the design optimization for joints using CF units under stress constraints. The stress state is solved; based on that, the maximum displacement under stress constraints is deduced. The natural frequency formula of the translational joint is further derived from the results of the stiffness matrix. The stage configurations corresponding to the maximum displacement are optimized by restricting the off-axis/axial stiffness ratio and natural frequency of the joint. The optimal results of different types are validated by FEA and experiments.
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