Continuously Variable Transmission and Stiffness Actuator Based on Actively Variable Four-Bar Linkage for Highly Dynamic Robot Systems

This letter presents a novel actuation mechanism that combines a continuously variable transmission (CVT) mechanism with a variable stiffness actuator (VSA) for highly dynamic robot systems such as legged robots. The CVT effectively changes the input-output transmission ratio of the system, thereby...

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Bibliographic Details
Published in:IEEE robotics and automation letters 2024-08, Vol.9 (8), p.7118-7125
Main Authors: Hur, Jungwoo, Song, Hangyeol, Jeong, Seokhwan
Format: Article
Language:English
Subjects:
Actuation
Actuators
actuators and sensors
applications (robotics)
Continuously variable
Couplings
design
Force
Knee
Legged locomotion
Linkage mechanisms
Mechanisms
mobility&locomotion
modeling&control
Robots
Springs
Stiffness
System effectiveness
Torque
Transmissions (automotive)
Citations: Items that this one cites
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Description
Summary:This letter presents a novel actuation mechanism that combines a continuously variable transmission (CVT) mechanism with a variable stiffness actuator (VSA) for highly dynamic robot systems such as legged robots. The CVT effectively changes the input-output transmission ratio of the system, thereby extending the operational torque-speed range. Concurrently, the VSA adjusts the system stiffness, altering its compliance characteristics. Both CVT and VSA are seamlessly integrated into a single four-bar linkage mechanism, with their active features enabled by an actively variable link within this linkage. This CVT-VSA mechanism offers a range of dynamic advantages by inversely varying transmission ratio and stiffness, which includes impact mitigation, torque or speed amplification, and expanded control bandwidth. The implementation and efficacy of the CVT-VSA mechanism in a legged robot were tested and validated through a series of experiments.
ISSN:2377-3766
2377-3766
DOI:10.1109/LRA.2024.3418268