Analysis and Comparison of Current Dependent Models of MR (Magnetoreological) Dampers Used in Knee Prosthesis


Sozeri G., YILMAZ A., ŞAHİN İ.

27th Signal Processing and Communications Applications Conference (SIU), Sivas, Turkey, 24 - 26 April 2019 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume:
  • Doi Number: 10.1109/siu.2019.8806306
  • City: Sivas
  • Country: Turkey
  • Hacettepe University Affiliated: Yes

Abstract

MR (magnetoreological) dampers are cylinders that can be controlled by electric current and are used in many different sectors from automotive to health. In this study, current dependant models of MR dampers designed for use in knee prostheses and comparison of models are discussed. Since hysteresis embedded in the dynamic structure of the damper is found to be critical in terms of complexity, Bingham and Dahl models are chosen for the comparison. In the first phase, force, displacement and velocity data were collected from the specially designed MR damper by the force gauge device of ROEHRIG. In total, the MR damper was operated at 11 different current values so that the force, displacement and velocity data were recorded for each. According to modelling purose, collected data were divided into two sets, specifically learning and testing sets. Using the pattern search optimization and ODE45 methods, the best parameter set of each model is determined. The best parameter set for the current dependency of the damper models is also described as the function of the current. In the last phase of the study, model errors are calculated and compared. According to the Mean Absolute Error criterion, Bingham and Dahl models were performed under the error rates of 17.16% and 5.98% respectively.