Controle da flexão e extensão do cotovelo via FES em malha-fechada utilizando controladores RST

Abstract

New studies that implement the technique of Functional Electrical Stimulation (FES) in closed loop are emerging, in order to control and generate desired movements in the limbs of people with motor disabilities. However, it still lacks efficiency and robustness in its results. Most projects use transfer functions for biomechanical movements present in the literature to design the control parameters. Taking into account that many factors can lead real models to distance themselves from theoretical biomechanical models, the present work presents the study and use of a technique for identifying discrete models from experimental data, in order to design RST controllers for elbow flexion and extension movements. As an initial study, all experiments were performed using software Opensim, an open source platform for musculoskeletal systems. PRBS entries were designed to be inserted into a model that contains the muscles responsible for elbow flexion and extension. Input and output data were collected so that a discrete model of the system could be identified. Subsequently, the RST parameters of two controllers were obtained, one for the flexion movement and the other for the extension movement. The performance of the controllers was evaluated operating individually and, later, in parallel, verifying a satisfactory performance considering the desired parameters. At the end, new studies are proposed to adapt the controller obtained in the simulation to be used in tests with real limbs.