Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Transient Thermal Analysis of a MR Clutch for Knee Prostheses and Exoskeletons
Submission Author:
Rafhael M Andrade , ES
Co-Authors:
Lucas de Amorim Paulo, Antonio Bento Filho, Claysson Vimieiro, Rafhael M Andrade
Presenter: Rafhael M Andrade
doi://10.26678/ABCM.COBEM2017.COB17-0311
Abstract
Magneto-rheological (MR) fluids are smart materials which can have their properties controlled by an induced magnetic field. MR fluids have been used in devices with multiple purposes. Despite the great characteristics and benefits, the MR fluid properties are strongly dependent on temperature. When the fluid temperature reaches certain limit, its additives begin to deteriorate and the viscosity of the carrier fluid starts to change, which can lead to irreversible changes on the MR fluid and uncontrollability of its rheology. This paper presents a transient thermal analysis of a high torque and low weight MR clutch used in a knee actuator for prosthesis in order to determine the conditions of safe operation without loss of fluid properties. Two thermal analyses are developed, the first one is in the no slip condition, which occurs during a ground walk, in this case the heat generation is caused by Joule effect in its coil. The second analysis is developed based on the full slip condition, when knee actuator is used to walking down steps, in this situation the heat generation is caused by friction and by Joule effect. Since the heat generation caused by friction is very higher, full slip condition is the most important operating condition and requires attention.
Keywords
Magneto-Rheological Actuator, prostheses, exoskeletons, biomechanics, Thermal Analysis
