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.

Shape-Adaptive Electrostatic Soft Gripper With Transform Mechanism for Multifunctional Grips

Abstract

This paper proposes a shape-adaptive electroadhesion dielectric elastomer actuator (EA-DEA) pad gripper that can actively adapt to the shape of curved objects and quickly handle various objects by combining an EA pad and a multi-layered DEA driven by electrostatic force. This gripper has a rapid release function capable of detaching thin and light objects in less than 0.2 s with bending motion of multi-layered DEA and reverse polarity voltage. Moreover, combined with a transform mechanism that changes the posture of the EA-DEA pad gripper, a multifunctional gripper handling various objects from thin to irregularly shaped objects is implemented. The high voltage controller is configured to generate the variable and reversible voltages required for the control of the developed gripper. To verify the performance and practicality of the proposed multifunctional gripper system, we demonstrate the gripping task in three modes formed by controlling the EA-DEA pad gripper and the transform mechanism to adapt to the object shape. According to the experimental results, this gripper can reliably and rapidly pick and place various objects, such as thin film, hexahedron, cylinders, spheres, irregular shaped, deformable, and fragile objects corresponding to each mode.

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