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.

Design and Development of the Transmission for a Fully Actuated 5-Degrees-of-Freedom Compliant Robot Manipulator With a Single Motor

Abstract

This article presents a novel architecture for the actuation and transmission system of a 5-degrees-of-freedom (DOFs) compliant robot manipulator. The compliant behavior of the robot is achieved using inherently compliant magneto-rheological (MR) clutches introduced in antagonistic pairs in every joint of the manipulator. All five antagonistic MR clutch pairs are driven using a single brushless DC motor located in the base of the robot. The MR clutch pairs are coupled to the motor through a system of shafts, belts, and gears. Several possible architectures for realizing a suitable drive train are presented, and the advantages and disadvantages of each concept are analyzed. The most efficient architecture for the drive train is selected to complete the design of the manipulator. The kinematics of the manipulator using the adopted architecture is further analyzed, and the workspace of the system is presented. To the best of our knowledge, this is the first 5-DOF, fully actuated, compliant robotic manipulator that uses a single DC motor to achieve five independent axes of rotations.

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