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.

WheTLHLoc: Small-Scale Hybrid Locomotion Robot With Stair Climbing Capability

Abstract

This paper discusses the theoretical analysis and the experimental validation of the step and stair climbing capability of wheel-track-leg hybrid locomotion (WheTLHLoc), a small-scale hybrid locomotion robot with overall size of 450 × 350 × 130 mm and maximum payload of 0.5 kg. The architecture of this robot combines two tracks, two rotating legs, two actuated wheels, and two passive omni wheels. The robot is capable of performing different locomotion modes: wheeled locomotion on flat and compact grounds with maximum speed of 0.9 m/s, tracked locomotion on soft and yielding terrains with maximum speed of 0.1 m/s, mixed use of tracks, legs, and wheels to overcome obstacles. In particular, the process of step and stair climbing is analyzed considering static stability and non-slipping conditions. The experimental campaign on the first prototype has confirmed the effectiveness of the proposed climbing maneuver for steps up to 165 mm and the operative flexibility of the WheTLHLoc robot.

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