Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
H∞ AND MODEL REFERENCE REFERENCE ADAPTIVE CONTROL OF A SERIES ELASTIC ACTUATOR FOR ROBOTIC REHABILITATION: PRELIMINARY RESULTS
Submission Author:
jonathan campo , SP
Co-Authors:
jonathan campo, Juan Carlos Pérez Ibarra, Felix Mauricio Escalante Ortega, ANDRES LEONARDO JUTINICO ALARCON, Marco Terra, Adriano Siqueira
Presenter: jonathan campo
doi://10.26678/ABCM.COBEM2017.COB17-1210
Abstract
Impedance Control of Series Elastic Actuators (SEAs) has been an established solution to dose the amount of assistance during robotic therapy. However, this approach requires an internal force control loop whose performance is sensitive to variations of the human dynamics. In previous papers we conclude that for this configuration, only a variable gain scheme that modify the force control parameters according to the human activity can ensure high performance for all of those variations. In this paper, we propose an adaptive control strategy based on H∞-synthesis and Model Reference Adaptive Control (MRAC). We use an H∞ force controller previously synthesized for an SEA-based robotic platform for ankle rehabilitation. The control signal provided by the H∞ controller guarantee robust stability and high performance of the platform’s force controller during a reference condition. For the remaining conditions, a MRAC adjusts the control signal by estimating adequate control parameters for the actual plant, compensating the variations of the system dynamics from the reference model. Results from simulations for four different conditions of operation shown improvements of the force tracking performance using the proposed adaptive scheme. This research is a starting point for future implementation in the actual platform and others SEA-based robotic systems.
Keywords
Force Control, Series Elastic Actuators, H∞ Control, Model Reference Adaptive Control, Impedance Control
