Modeling, Analysis, and Experimental Validation of an Electric Linear Series Elastic Actuator for an Exoskeleton

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2020-06-26
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Virginia Tech
Abstract

Exoskeletons and humanoid robots require high-power, low-weight, and back-driveable actuators. This paper describes the design and analysis of a high-force linear series elastic actuator for a lower body exoskeleton. The actuator is powered by two motors and utilize a liquid cooling system to increase its maximum continuous torque. The actuator is capable of outputting a maximum continuous force of 4800N and a maximum speed of 0.267 m/s with a maximum continuous motor current of 18A. The Titanium leaf spring was used in the actuator to provide compliance. The spring has a median stiffness of 587 N/mm with standard deviation of 38 N/mm, validated by experiments. Dynamic model was created to analyze the normal modes and can be used for developing model-based controllers.

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Keywords
Series Elastic Actuators, Liquid Cooling System, Dynamic Modeling, Transfer Function, Exoskeleton
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