Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
DESIGN OF A LOW-COST SERIES ELASTIC ACTUATOR FOR APPLICATION IN ROBOTIC MANIPULATORS
Submission Author:
Felipe Rebelo Lopes , RJ
Co-Authors:
Felipe Rebelo Lopes, Marco Antonio Meggiolaro
Presenter: Felipe Rebelo Lopes
doi://10.26678/ABCM.COBEM2021.COB2021-1640
Abstract
The development of technologies in Human-Robot Interaction (HRI) field has increased with the concern to create robots that can perform dynamic tasks to collaborate with humans. One of these technologies is the Series Elastic Actuator (SEA), which offers advantages such as high quality of force/torque control, low impedance and shock tolerance. Flexibility is added to the robot by an elastic element (usually a spring) between each motor and its load. This paper presents the design of a modular and low cost eSEA (elastomer-based Series Elastic Actuator) for applications in robotic manipulators. The proposed eSEA is composed of three parts: the rigid internal and external parts are made of aluminum, while between them there is an elastic element made of an elastomer. Two encoders attached to each rigid element are then used to evaluate in real time the joint angles and the deformation of the elastic element. The eSEA is 3D modeled in software Solidworks and motion simulations are implemented in the ANSYS software. Experimental tests are performed with two different elastomers: the first with a very low hardness about 9-10 Shore A, while the second with about 55 Shore A. A test bench is created to obtain the torque x angular displacement profile of the developed eSEA, identifying elastic constants and sensor resolution. In the experiments, to generate known torques, test weights are positioned on a lever arm attached to the external part of the eSEA and to one of the encoders. These torques are compared to the torques measured by the controller board. The internal part of the SEA is attached to the motor axis, which is then connected to the second encoder. The calibrated eSEAs are mounted on especially developed planar robotic arms based on a 4-bar linkage, where their ability to estimate joint torques is used to improve the force and displacement control characteristics of the robot.
Keywords
Series Elastic Actuators, Human-Robot Interaction, Flexible joint
