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Mathematical Problems in Engineering
Volume 2015, Article ID 736246, 8 pages
Research Article

Robust Control of the Knee Joint Angle of Paraplegic Patients considering Norm-Bounded Uncertainties

1Engenharia Elétrica, Área de Exatas, Faculdade Ingá, Rodovia PR 317, No. 6114, 87035-510 Maringá, PR, Brazil
2Department of Electrical Engineering, Urban Planning and Technology Center, State University of Londrina, Rodovia Celso Garcia Cid PR 445, Km 380, 86057-970 Londrina, PR, Brazil
3Department of Electrical Engineering, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, 15385-000 Ilha Solteira, SP, Brazil

Received 4 September 2014; Revised 17 December 2014; Accepted 18 December 2014

Academic Editor: John Gunnar Carlsson

Copyright © 2015 Nilson Moutinho dos Santos et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A proposal for the knee position control design of paraplegic patients with functional electrical stimulation (FES) using control systems and considering norm-bounded uncertainties is presented. A state-space representation of the knee joint model of the paraplegic patient with its nonlinearity is also demonstrated. The use of linear matrix inequalities (LMIs) in control systems with norm-bounded uncertainties for asymptotic stability is analyzed. The model was simulated in the Matlab environment. The matrix of state space feedback was obtained through LMIs.