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Bibliographic Details
Main Authors: Girard, Alexandre, Asada, H. Harry
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2405.14441
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author Girard, Alexandre
Asada, H. Harry
author_facet Girard, Alexandre
Asada, H. Harry
contents This paper presents a robotic system where the gear-ratio of an actuator is dynamically changed to either leverage or attenuate the natural load dynamics. Based on this principle, lightweight robotic systems can be made fast and strong; exploiting the natural load dynamics for moving at higher speeds (small reduction ratio), while also able to bear a large load through the attenuation of the load dynamics (large reduction ratio). A model-based control algorithm to automatically select the optimal gear-ratios that minimize the total actuator torques for an arbitrary dynamic state and expected uncertainty level is proposed. Also, a novel 3-DoF robot arm using custom actuators with two discrete gear-ratios is presented. The advantages of gear-shifting dynamically are demonstrated through experiments and simulations. Results show that actively changing the gear-ratio using the proposed control algorithms can lead to an order-of-magnitude reduction of necessary actuator torque and power, and also increase robustness to disturbances.
format Preprint
id arxiv_https___arxiv_org_abs_2405_14441
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Leveraging Natural Load Dynamics with Variable Gear-ratio Actuators
Girard, Alexandre
Asada, H. Harry
Robotics
This paper presents a robotic system where the gear-ratio of an actuator is dynamically changed to either leverage or attenuate the natural load dynamics. Based on this principle, lightweight robotic systems can be made fast and strong; exploiting the natural load dynamics for moving at higher speeds (small reduction ratio), while also able to bear a large load through the attenuation of the load dynamics (large reduction ratio). A model-based control algorithm to automatically select the optimal gear-ratios that minimize the total actuator torques for an arbitrary dynamic state and expected uncertainty level is proposed. Also, a novel 3-DoF robot arm using custom actuators with two discrete gear-ratios is presented. The advantages of gear-shifting dynamically are demonstrated through experiments and simulations. Results show that actively changing the gear-ratio using the proposed control algorithms can lead to an order-of-magnitude reduction of necessary actuator torque and power, and also increase robustness to disturbances.
title Leveraging Natural Load Dynamics with Variable Gear-ratio Actuators
topic Robotics
url https://arxiv.org/abs/2405.14441