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.

Multi-Furcation Variations of Two Novel Double-Centered Mechanisms Based on Higher Order Kinematic Analyses and Singular Value Decomposition

Abstract

This paper explores a class of extended double-centered linkages and presents two novel multi-bifurcated double-centered metamorphic and reconfigurable mechanisms. Higher order kinematic analyses and singular value decomposition are combined to demonstrate the characteristics of multi-furcation and to reveal motion branch transformation. These findings show that the presented double-centered linkages are able to evolve to distinct motion branches including two spherical 4R linkages, line-symmetric Bricard linkage or Bennett linkage. Furthermore, by exploring the local properties of singular configurations on geometric constraints and algebraic relationships, a systematic approach for the synthesis of the singular configurations can be designed to discover more novel multi-bifurcated metamorphic and reconfigurable mechanisms.

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