Spider-Inspired Electrohydraulic Actuators for Fast, Soft-Actuated Joints

2021

Article

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The impressive locomotion and manipulation capabilities of spiders have led to a host of bioinspired robotic designs aiming to reproduce their functionalities; however, current actuation mechanisms are deficient in either speed, force output, displacement, or efficiency. Here—using inspiration from the hydraulic mechanism used in spider legs—soft-actuated joints are developed that use electrostatic forces to locally pressurize a hydraulic fluid, and cause flexion of a segmented structure. The result is a lightweight, low-profile articulating mechanism capable of fast operation, high forces, and large displacement; these devices are termed spider-inspired electrohydraulic soft-actuated (SES) joints. SES joints with rotation angles up to 70°, blocked torques up to 70 mN m, and specific torques up to 21 N m / kg are demonstrated. SES joints demonstrate high speed operation, with measured roll-off frequencies up to 24 Hz and specific power as high as 230 W/kg—similar to human muscle. The versatility of these devices is illustrated by combining SES joints to create a bidirectional joint, an artificial limb with independently addressable joints, and a compliant gripper. The lightweight, low-profile design, and high performance of these devices, makes them well-suited toward the development of articulating robotic systems that can rapidly maneuver.

@article{Kellaris21-AS-Spider,
  title = {Spider-Inspired Electrohydraulic Actuators for Fast, Soft-Actuated Joints},
  author = {Kellaris, Nicholas and Rothemund, Philipp and Zeng, Yi and Mitchell, Shane K. and Smith, Garret M. and Jayaram, Kaushik and Keplinger, Christoph},
  journal = {Advanced Science},
  volume = {8},
  number = {14},
  pages = {2100916},
  year = {2021},
  doi = {10.1002/advs.202100916}
}