Open AccessA Wiener Model Based Closed Loop FES for Positional Control During Wrist Flexion
Author(s) -
S. J. Mahendra,
Vishwanath Talasila,
Abhilash G. Dutt
Publication year - 2021
Publication title -
international journal of circuits, systems and signal processing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.156
H-Index - 13
ISSN - 1998-4464
DOI - 10.46300/9106.2021.15.91
Subject(s) - functional electrical stimulation , wrist , controller (irrigation) , control theory (sociology) , work (physics) , computer science , angular displacement , pid controller , nonlinear system , closed loop , physical medicine and rehabilitation , control (management) , stimulation , artificial intelligence , control engineering , engineering , mathematics , psychology , medicine , physics , anatomy , neuroscience , mechanical engineering , temperature control , geometry , quantum mechanics , biology , agronomy
Functional electrical stimulation is an assistive technique used to produce functional movements in patients suffering from neurological impairments. However, existing open-loop clinical FES systems are not adequately equipped to compensate for the nonlinear, time-varying behaviour of the muscles. On the other hand, closed-loop FES systems can compensate for the aforementioned effects by regulating the stimulation to induce desired contractions. Therefore, this work aims to present an approach to implement a closed-loop FES system to enable angular positional control during wrist flexion. First, a Wiener model describing the response of the wrist flexor to pulse width modulated stimulation was identified for two healthy volunteers. Second, a nonlinear PID controller (subject-specific) was designed based on the identified models to enable angular positional control during wrist flexion. Subsequently, the controller was implemented in real-time and was tested against two reference angles on healthy volunteers. This study shows promise that the presented closed-loop FES approach can beimplemented to control the angular position during wrist flexion or a novelty of the work when compared with the existing work.